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The acronym refers to its deuterium oxide heavy water moderator and its use of originally, natural uranium fuel. There have been two major types of CANDU reactors, the original design of around MW e that was intended to be used in multi-reactor installations in large plants, and the rationalized CANDU 6 in the MW e class that is designed to be used in single stand-alone units or in small multi-unit plants.

By the early s, sales prospects for the original CANDU designs were dwindling due to the introduction of newer designs from other companies. ACR failed to find any buyers; its last potential sale was for an expansion at Darlington, but this was cancelled in Candu Energy offers support services for existing sites and is completing formerly stalled installations in Romania and Argentina through a partnership with China National Nuclear Corporation.

Sales effort for the ACR reactor has ended. In , a consultation with industry led Natural Resources Canada to establish a “SMR Roadmap” [1] targeting the development of small modular reactors. Fission reactions in the reactor core heat pressurized water in a primary cooling loop. A heat exchanger , also known as a steam generator , transfers the heat to a secondary cooling loop , which powers a steam turbine with an electric generator attached to it for a typical Rankine thermodynamic cycle.

The exhaust steam from the turbines is then cooled, condensed and returned as feedwater to the steam generator. The final cooling often uses cooling water from a nearby source, such as a lake, river, or ocean. Newer CANDU plants, such as the Darlington Nuclear Generating Station near Toronto , Ontario, use a diffuser to spread the warm outlet water over a larger volume and limit the effects on the environment. Where the CANDU design differs from most other designs is in the details of the fissile core and the primary cooling loop.

Natural uranium consists of a mix of mostly uranium with small amounts of uranium and trace amounts of other isotopes. Fission in these elements releases high-energy neutrons , which can cause other U atoms in the fuel to undergo fission as well. This process is much more effective when the neutron energies are much lower than what the reactions release naturally. Most reactors use some form of neutron moderator to lower the energy of the neutrons, or ” thermalize ” them, which makes the reaction more efficient.

The energy lost by the neutrons during this moderation process heats the moderator, and this heat is extracted for power. Most commercial reactor designs use normal water as the moderator. Water absorbs some of the neutrons, enough that it is not possible to keep the reaction going in natural uranium.

CANDU replaces this “light” water with heavy water. Heavy water’s extra neutron decreases its ability to absorb excess neutrons, resulting in a better neutron economy. This allows CANDU to run on unenriched natural uranium , or uranium mixed with a wide variety of other materials such as plutonium and thorium. This was a major goal of the CANDU design; by operating on natural uranium the cost of enrichment is removed.

This also presents an advantage in nuclear proliferation terms, as there is no need for enrichment facilities, which might also be used for weapons. In conventional light-water reactor LWR designs, the entire fissile core is placed in a large pressure vessel.

The amount of heat that can be removed by a unit of a coolant is a function of the temperature; by pressurizing the core, the water can be heated to much greater temperatures before boiling , thereby removing more heat and allowing the core to be smaller and more efficient.

Building a pressure vessel of the required size is a significant challenge, and at the time of the CANDU’s design, Canada’s heavy industry lacked the requisite experience and capability to cast and machine reactor pressure vessels of the required size. This problem is amplified by natural uranium fuel’s lower fissile density, which requires a larger reactor core.

This issue was so major that even the relatively small pressure vessel originally intended for use in the NPD prior to its mid-construction redesign could not be fabricated domestically and had to be manufactured in Scotland instead.

Domestic development of the technology required to produce pressure vessels of the size required for commercial-scale heavy water moderated power reactors was thought to be very unlikely. The bundles are contained in pressure tubes within a larger vessel containing additional heavy water acting purely as a moderator. This larger vessel, known as a calandria, is not pressurized and remains at much lower temperatures, making it much easier to fabricate. In order to prevent the heat from the pressure tubes from leaking into the surrounding moderator, each pressure tube is enclosed in a calandria tube.

Carbon dioxide gas in the gap between the two tubes acts as an insulator. The moderator tank also acts as a large heat sink that provides an additional safety feature. In a conventional pressurized water reactor , refuelling the system requires to shut down the core and to open the pressure vessel.

This allows the CANDU system to be continually refuelled without shutting down, another major design goal. In modern systems, two robotic machines attach to the reactor faces and open the end caps of a pressure tube. One machine pushes in the new fuel, whereby the depleted fuel is pushed out and collected at the other end. A significant operational advantage of online refuelling is that a failed or leaking fuel bundle can be removed from the core once it has been located, thus reducing the radiation levels in the primary cooling loop.

Each fuel bundle is a cylinder assembled from thin tubes filled with ceramic pellets of uranium oxide fuel fuel elements. In older designs, the bundle had 28 or 37 half-meter-long fuel elements with 12—13 such assemblies lying end-to-end in a pressure tube.

The newer CANFLEX bundle has 43 fuel elements, with two element sizes so the power rating can be increased without melting the hottest fuel elements. It is about 10 centimetres 3. Natural uranium is a mix of isotopes , mainly uranium , with 0. A reactor aims for a steady rate of fission over time, where the neutrons released by fission cause an equal number of fissions in other fissile atoms.

This balance is referred to as criticality. The neutrons released in these reactions are fairly energetic and don’t readily react with get “captured” by the surrounding fissile material. In order to improve this rate, they must have their energy moderated , ideally to the same energy as the fuel atoms themselves.

As these neutrons are in thermal equilibrium with the fuel, they are referred to as thermal neutrons. Since most of the fuel is usually U, most reactor designs are based on thin fuel rods separated by moderator, allowing the neutrons to travel in the moderator before entering the fuel again.

More neutrons are released than are needed to maintain the chain reaction; when uranium absorbs just the excess, plutonium is created, which helps to make up for the depletion of uranium Eventually the build-up of fission products that are even more neutron-absorbing than U slows the reaction and calls for refuelling. Light water makes an excellent moderator: the light hydrogen atoms are very close in mass to a neutron and can absorb a lot of energy in a single collision like a collision of two billiard balls.

Light hydrogen is also fairly effective at absorbing neutrons, and there will be too few left over to react with the small amount of U in natural uranium, preventing criticality. In order to allow criticality, the fuel must be enriched , increasing the amount of U to a usable level.

Enrichment facilities are expensive to build and operate. This can be remedied if the fuel is supplied and reprocessed by an internationally approved supplier.

The main advantage of heavy-water moderator over light water is the reduced absorption of the neutrons that sustain the chain reaction, allowing a lower concentration of active atoms to the point of using unenriched natural uranium fuel.

Deuterium “heavy hydrogen” already has the extra neutron that light hydrogen would absorb, reducing the tendency to capture neutrons. Deuterium has twice the mass of a single neutron vs light hydrogen, which has about the same mass ; the mismatch means that more collisions are needed to moderate the neutrons, requiring a larger thickness of moderator between the fuel rods. This increases the size of the reactor core and the leakage of neutrons. It is also the practical reason for the calandria design, otherwise, a very large pressure vessel would be needed.

In CANDU most of the moderator is at lower temperatures than in other designs, reducing the spread of speeds and the overall speed of the moderator particles. This means that most of the neutrons will end up at a lower energy and be more likely to cause fission, so CANDU not only “burns” natural uranium, but it does so more effectively as well. This is a major advantage of the heavy-water design; it not only requires less fuel, but as the fuel does not have to be enriched, it is much less expensive as well.

A further unique feature of heavy-water moderation is the greater stability of the chain reaction. This is due to the relatively low binding energy of the deuterium nucleus 2. Both gammas produced directly by fission and by the decay of fission fragments have enough energy, and the half-lives of the fission fragments range from seconds to hours or even years.

The slow response of these gamma-generated neutrons delays the response of the reactor and gives the operators extra time in case of an emergency. Since gamma rays travel for meters through water, an increased rate of chain reaction in one part of the reactor will produce a response from the rest of the reactor, allowing various negative feedbacks to stabilize the reaction. On the other hand, the fission neutrons are thoroughly slowed down before they reach another fuel rod, meaning that it takes neutrons a longer time to get from one part of the reactor to the other.

Thus if the chain reaction accelerates in one section of the reactor, the change will propagate itself only slowly to the rest of the core, giving time to respond in an emergency. The independence of the neutrons’ energies from the nuclear fuel used is what allows such fuel flexibility in a CANDU reactor, since every fuel bundle will experience the same environment and affect its neighbors in the same way, whether the fissile material is uranium, uranium or plutonium.

Canada developed the heavy-water-moderated design in the post— World War II era to explore nuclear energy while lacking access to enrichment facilities. War-era enrichment systems were extremely expensive to build and operate, whereas the heavy water solution allowed the use of natural uranium in the experimental ZEEP reactor.

A much less expensive enrichment system was developed, but the United States classified work on the cheaper gas centrifuge process. Some of these are a side effect of the physical layout of the system. CANDU designs have a positive void coefficient , as well as a small power coefficient, normally considered bad in reactor design.

This implies that steam generated in the coolant will increase the reaction rate, which in turn would generate more steam. This is one of the many reasons for the cooler mass of moderator in the calandria, as even a serious steam incident in the core would not have a major impact on the overall moderation cycle. Only if the moderator itself starts to boil, would there be any significant effect, and the large thermal mass ensures that this will occur slowly. The deliberately “sluggish” response of the fission process in CANDU allows controllers more time to diagnose and deal with problems.

The fuel channels can only maintain criticality if they are mechanically sound. If the temperature of the fuel bundles increases to the point where they are mechanically unstable, their horizontal layout means that they will bend under gravity, shifting the layout of the bundles and reducing the efficiency of the reactions.

Because the original fuel arrangement is optimal for a chain reaction, and the natural uranium fuel has little excess reactivity, any significant deformation will stop the inter-fuel pellet fission reaction. This will not stop heat production from fission product decay, which would continue to supply a considerable heat output.

If this process further weakens the fuel bundles, the pressure tube they are in will eventually bend far enough to touch the calandria tube, allowing heat to be efficiently transferred into the moderator tank. The moderator vessel has a considerable thermal capability on its own and is normally kept relatively cool.

The CANDU designs have several emergency cooling systems, as well as having limited self-pumping capability through thermal means the steam generator is well above the reactor. Even in the event of a catastrophic accident and core meltdown , the fuel is not critical in light water. Normally the rate of fission is controlled by light-water compartments called liquid zone controllers, which absorb excess neutrons, and by adjuster rods, which can be raised or lowered in the core to control the neutron flux.

These are used for normal operation, allowing the controllers to adjust reactivity across the fuel mass, as different portions would normally burn at different rates depending on their position. The adjuster rods can also be used to slow or stop criticality. Because these rods are inserted into the low-pressure calandria, not the high-pressure fuel tubes, they would not be “ejected” by steam, a design issue for many pressurized-water reactors.

There are two independent, fast-acting safety shutdown systems as well. Shutoff rods are held above the reactor by electromagnets and drop under gravity into the core to quickly end criticality.

This system works even in the event of a complete power failure, as the electromagnets only hold the rods out of the reactor when power is available.

The S6G reactor is a naval reactor used by the United States Navy to provide electricity generation and propulsion on Los Angeles-class attack replace.me S6G designation stands for: S = Submarine platform 6 = Sixth generation core designed by the contractor; G = General Electric was the contracted designer Design. This nuclear reactor was designed by General . Dec 23, · Waveform Free is a free digital audio workstation developed by Tracktion Corporation. The DAW is the core of every music production software setup, and Waveform Free is the best one you can get for free. This powerful music-making tool works on all major platforms (Windows, macOS, and Linux) and provides all the features necessary for recording . History. The first modular synthesizer was developed by German engineer Harald Bode in the late s. The s saw the introduction of the Moog synthesizer and the Buchla Modular Electronic Music System, created around the same period. The Moog was composed of separate modules which created and shaped sounds, such as envelopes, noise generators, filters, and . A fluidized bed reactor (FBR) is a type of reactor device that can be used to carry out a variety of multiphase chemical reactions. In this type of reactor, a fluid (gas or liquid) is passed through a solid granular material (usually a catalyst) at high enough speeds to suspend the solid and cause it to behave as though it were a replace.me process, known as fluidization, imparts many.

List of nuclear reactors Finland Hanhikivi Nuclear Power Plant Nuclear engineering Nuclear power in Finland Onkalo spent nuclear fuel repository Into Eternity , a documentary about the construction of a Finnish waste depository Journey to the Safest Place on Earth , a documentary about the urgent need for safe depositories. Energy Storage News. Archived from the original on 16 June Retrieved 28 August World Nuclear News.

Retrieved 17 June Retrieved 2 February Teollisuuden Voima. January Retrieved 16 April International Nuclear Safety Center.

Archived from the original on 3 December Retrieved 13 March Nuclear Engineering International. Archived from the original on 4 September Retrieved 12 January Retrieved 7 January Retrieved 20 September Retrieved 2 July Retrieved 24 July Retrieved 10 August Retrieved 15 April Worldwatch Institute. Archived from the original on 27 September Helsingin Sanomat.

Archived from the original on 20 October Power Reactor Information System. Archived from the original on 19 September Nuclear Street. Retrieved 9 December Retrieved 16 December Retrieved 29 January Archived from the original on 26 February Financial Times. Archived from the original on 1 February Retrieved 18 January Retrieved 27 February Archived from the original on 4 March Retrieved 28 February Retrieved 17 July Power Engineering. Retrieved 23 November Retrieved 29 November Retrieved 13 December The Wall Street Journal.

Retrieved 4 December Retrieved 12 March Retrieved 4 June Retrieved 7 March Physicians for Social Responsibility. Archived from the original on 28 July Archived from the original on 13 June Retrieved 21 February Archived from the original on 13 February Retrieved 14 December Radiation and Nuclear Safety Authority.

Retrieved 18 June Yle Uutiset. Archived from the original on 26 March Retrieved 26 March Retrieved 23 August Categories : Nuclear power stations in Finland Radioactive waste repositories Nuclear power stations using boiling water reactors Nuclear power stations using pressurized water reactors Nuclear power stations with reactors under construction Nuclear power stations with proposed reactors Nuclear power stations using EPR reactors Eurajoki Buildings and structures in Satakunta.

Namespaces Article Talk. Views Read Edit View history. Help Learn to edit Community portal Recent changes Upload file. Download as PDF Printable version. Wikimedia Commons. Olkiluoto Nuclear Power Plant in Eurajoki , Region of Satakunta.

Gulf of Bothnia. Olkiluoto nuclear power plant. Related media on Commons. TVO applies to the Finnish cabinet for a decision-in-principle on the new unit [65]. Siemens withdraws from the joint venture with Areva, leaving the latter as the main contractor [66].

TVO said that it is “preparing for the possibility” that the third unit at Olkiluoto may not start operating until [68]. Areva shutting down construction due to dispute over compensations and unfinished automation planning. In addition to the separative work units provided by an enrichment facility, the other important parameter to be considered is the mass of natural uranium NU that is needed to yield a desired mass of enriched uranium.

As with the number of SWUs, the amount of feed material required will also depend on the level of enrichment desired and upon the amount of U that ends up in the depleted uranium. However, unlike the number of SWUs required during enrichment, which increases with decreasing levels of U in the depleted stream, the amount of NU needed will decrease with decreasing levels of U that end up in the DU. For example, in the enrichment of LEU for use in a light water reactor it is typical for the enriched stream to contain 3.

On the other hand, if the depleted stream had only 0. Because the amount of NU required and the number of SWUs required during enrichment change in opposite directions, if NU is cheap and enrichment services are more expensive, then the operators will typically choose to allow more U to be left in the DU stream whereas if NU is more expensive and enrichment is less so, then they would choose the opposite.

When converting uranium hexafluoride, hex for short to metal,. The opposite of enriching is downblending; surplus HEU can be downblended to LEU to make it suitable for use in commercial nuclear fuel. High concentrations of U are a byproduct from irradiation in a reactor and may be contained in the HEU, depending on its manufacturing history.

The production of U is thus unavoidable in any thermal neutron reactor with U fuel. HEU reprocessed from nuclear weapons material production reactors with an U assay of approx. While U also absorbs neutrons, it is a fertile material that is turned into fissile U upon neutron absorption.

If U absorbs a neutron, the resulting short-lived U beta decays to Np , which is not usable in thermal neutron reactors but can be chemically separated from spent fuel to be disposed of as waste or to be transmutated into Pu for use in nuclear batteries in special reactors. So, the HEU downblending generally cannot contribute to the waste management problem posed by the existing large stockpiles of depleted uranium.

At present, 95 percent of the world’s stocks of depleted uranium remain in secure storage. From through mid, tonnes of high-enriched uranium enough for 10, warheads was recycled into low-enriched-uranium. The goal is to recycle tonnes by The United States Enrichment Corporation has been involved in the disposition of a portion of the Through the U. Countries that had enrichment programs in the past include Libya and South Africa, although Libya’s facility was never operational.

During the Manhattan Project , weapons-grade highly enriched uranium was given the codename oralloy , a shortened version of Oak Ridge alloy, after the location of the plants where the uranium was enriched. From Wikipedia, the free encyclopedia. Uranium in which isotope separation has been used to increase its proportion of uranium Main article: Reprocessed uranium. Main article: Gaseous diffusion. Main article: Gas centrifuge.

Main article: Calutron. Further information: Separative work units. Retrieved 5 February Nuclear Energy Today. OECD Publishing. ISBN Proceedings of international forum on illegal nuclear traffic. Archived from the original PDF on 22 July June Retrieved 1 July Princeton University.

Retrieved 18 April March Oak Ridge National Laboratories. Archived from the original PDF on 2 November Retrieved 30 October Nuclear Weapons FAQ. Retrieved 2 October Retrieved 19 December The enrichment of the pin and of one of the hemispheres was Retrieved 26 January Von Hippel; Laura H.

Kahn December S2CID To produce the same amount of reactor-grade fuel requires a considerably larger number approximately 50, to , of centrifuge units than diffusion units. Silex Ltd. Atomic Insights. Archived from the original on 28 January The s facility is the last remaining gaseous diffusion uranium enrichment plant in the world.

Duarte and L. Hillman Eds. GE Energy. Archived from the original on 14 June Business Wire. Retrieved 30 September The New York Times. Retrieved 21 August September Bibcode : NW Retrieved 7 November Archived from the original on 6 April December Uranium enrichment PDF.

Institute for Energy and Environmental Research. Retrieved 21 November Standing Committee on Industry and Resources Report. The Parliament of the Commonwealth of Australia. November Retrieved 3 April BBC News. Retrieved 3 January The Sydney Morning Herald. Nuclear Weapon Archive. Retrieved 7 October Retrieved 27 November Oralloy [Oak Ridge alloy] was a term of art for highly-enriched uranium.

Look up enriched uranium in Wiktionary, the free dictionary. Nuclear technology. Fast-neutron Neutron capture therapy of cancer Targeted alpha-particle Proton-beam Tomotherapy Brachytherapy Radiation therapy Radiosurgery Radiopharmacology.

A nuclear meltdown core meltdowncore melt accidentmeltdown or partial core melt [2] is a severe nuclear reactor accident that results in core damage from overheating. A core meltdown accident occurs when the heat generated by a nuclear reactor exceeds the heat licrnse reaktor 6 license free нажмите чтобы увидеть больше cooling systems to the point where at least one nuclear fuel element exceeds its melting point.

This differs from a fuel element failurewhich is not caused by high temperatures. A meltdown may be caused by a loss of coolantloss of coolant pressure, or reaktor 6 license free coolant fres rate reaktor 6 license free be windows 10 hibernate vs sleep mode free download result of a criticality excursion in which the reactor is operated rexktor a power level that exceeds its design limits.

Alternatively, reaktor 6 license free external fire may endanger the core, leading to a meltdown. Once the fuel elements of a microsoft windows 10 download begin to melt, the fuel cladding has been breached, and the nuclear fuel such as uraniumplutoniumreaktor 6 license free thorium and fission products such as caesiumkryptonor iodine within the fuel elements can leach out into the coolant. Subsequent failures can permit these radioisotopes to breach further layers of containment.

Superheated steam and hot metal inside the core microsoft office 2007 professional edition product key free lead to fuel—coolant interactionshydrogen explosionsor steam hammer reaktor 6 license free, any of which could destroy parts of the containment.

A meltdown is considered very serious because of the potential reaktor 6 license free radioactive reaktor 6 license free to breach all containment and escape or be released into the environmentresulting in radioactive contamination and falloutand potentially leading to radiation poisoning of people and animals nearby.

Nuclear power plants generate electricity by heating fluid via a nuclear reaction to run a generator. If the heat from that reaction is not removed adequately, the fuel assemblies in a reactor core can melt. A core damage incident can occur even after a reactor is shut down because the fuel continues to produce decay heat. A core damage accident is caused by the loss of sufficient cooling for the nuclear fuel within the reactor reaktor 6 license free.

The reason may be one of several factors, including a loss-of-pressure-control accidenta loss-of-coolant accident LOCAan uncontrolled power excursion or, in reactors without a pressure vessela fire within the reactor core. Failures in control systems may cause a series of events resulting in loss of cooling.

Contemporary safety principles of defense in depth ensure that multiple layers of safety systems are always present to make such accidents unlikely. The containment building is reaktor 6 license free last of several safeguards that prevent the release reaktor 6 license free radioactivity to the environment.

Many commercial reactors are contained within a 1. Before the core of a light-water nuclear reactor can be damaged, two precursor events must have already occurred:.

The Three Mile Island accident was a compounded group of emergencies that led to core damage. What led to this was an erroneous decision by operators to shut down the ECCS during an emergency condition due to gauge readings that were either incorrect or misinterpreted; this caused another emergency condition that, several hours after the fact, led to core exposure and a reakttor damage incident.

If the ECCS had been allowed to function, it would have prevented both exposure and core damage. During the Fukushima incident the emergency cooling system had also been manually shut down several minutes after it started. If such a limiting fault were to occur, and a complete failure of all ECCS divisions were to occur, both Ссылка на страницу, et al and Haskin, et al describe six stages between the start of the limiting fault the loss of cooling and the potential escape of molten corium into the containment a so-called “full meltdown” : [8] [9].

At the point at which the corium relocates to the lower plenum, Haskin, et al relate that the possibility exists for an incident called a fuel—coolant interaction Reaktor 6 license free to substantially stress or breach the primary pressure boundary when the corium relocates to the lower plenum of the reactor pressure vessel “RPV”. The American Nuclear Society has commented on the TMI-2 accident, that despite melting of about rea,tor of the fuel, the reactor vessel itself maintained its integrity and contained the damaged fuel.

There are several possibilities as to how the primary pressure boundary could be breached by corium. As previously described, FCI could lead to an overpressure event leading to RPV fail, and thus, primary pressure boundary fail.

Haskin et al report that in the event rektor a steam explosion, failure of the lower plenum is far more likely than ejection of the upper plenum in the alpha mode. In the event of lower plenum failure, debris at varied temperatures can be expected to be projected licenee the cavity below the core.

The containment may be subject to overpressure, though this is not likely to fail the containment. The alpha-mode failure will lead to the consequences previously discussed. It is quite possible, especially in pressurized water reactors, that the primary loop will remain pressurized following corium relocation to the lower plenum.

As such, pressure stresses on the RPV will be present in addition to the weight stress that the molten corium places on the lower plenum of the RPV; when the metal of the RPV weakens sufficiently due to the heat reaktor 6 license free the molten corium, it is likely that the liquid corium will be discharged under pressure out of the bottom of the RPV in a pressurized stream, lidense with entrained gases. This mode of corium ejection may lead to direct containment heating Reaktro.

Haskin et al identify six modes by which the containment could be credibly challenged; some of these modes are not reaktorr to core melt accidents. If the melted core penetrates the pressure vessel, there are theories and speculations as to what may then occur. In modern Russian plants, there is a “core catching device” in the bottom of the containment building. The melted core is supposed to hit a thick layer of a “sacrificial metal” that would melt, dilute the core and increase the heat conductivity, and finally the diluted core can be cooled down by water circulating in the floor.

There has never been any full-scale testing reaktor 6 license free licenxe device, however. Rexktor Western plants there is an airtight containment building.

Though radiation would be at a high level within the containment, doses outside of it would be lower. Containment buildings are designed for the orderly release of pressure without releasing radionuclides, through a pressure release valve and filters. In a melting event, one spot or area on lixense RPV will become hotter than other areas, and will eventually melt.

When it melts, corium will pour into the cavity under the reactor. Though the cavity is designed to reaktor 6 license free dry, several NUREG-class documents advise licehse to flood the cavity in the event of a fuel melt incident. This water will become reaktor 6 license free and pressurize the containment. Automatic water sprays will pump large quantities of water into the steamy environment to keep the pressure down. Catalytic recombiners will rapidly convert the hydrogen and oxygen back into water.

One positive effect of the corium falling into water is that it is cooled and returns to a solid state. Extensive water spray systems within the containment along with the ECCS, when it is reactivated, will allow reaktor 6 license free to spray water within the containment to cool the core on the floor and reduce it to a low temperature.

These procedures are intended frre prevent release of radioactivity. In the Three Mile Island event ina theoretical person standing at the plant property line during the entire event would have received a dose of approximately 2 millisieverts millirembetween a chest X-ray’s and a CT scan’s worth of radiation. This was due to outgassing by an uncontrolled system that, today, would have been backfitted with activated carbon and HEPA filters to prevent radionuclide release.

In the Fukushima incident, however, this design failed. Despite the efforts of the operators at the Fukushima Daiichi nuclear power plant to maintain control, the reactor cores in units 1—3 overheated, the nuclear fuel melted and the three containment vessels were breached. Hydrogen was released from the reactor pressure vessels, leading to explosions inside the reactor buildings in units 1, 3 and 4 that damaged reaktor 6 license free and equipment and injured personnel.

Radionuclides were released from the plant to the atmosphere and were deposited on land and on the ocean. There were also direct releases into the sea. As the natural decay heat of the corium eventually reduces to an equilibrium with reaktpr and conduction to the containment walls, it becomes cool enough for water spray systems to be shut down and the reactor reaktor 6 license free be put fdee safe storage.

The containment can be sealed with release of extremely limited offsite radioactivity and release of pressure. After perhaps a decade for fission products to decay, the containment can be reopened for decontamination and demolition. Another scenario sees a buildup of potentially explosive reakktor, but passive autocatalytic recombiners inside the containment are designed to prevent this.

In Fukushima, the containments were filled with inert nitrogen, which prevented hydrogen from burning; the hydrogen leaked from the containment to the reactor building, however, where it mixed with air and exploded. There were initial concerns that the hydrogen might ignite and damage the pressure vessel or even the containment building; but it was soon realized that lack of oxygen prevented burning or explosion.

One scenario consists of the reactor pressure vessel failing all at once, with the entire mass of corium dropping into a pool of water for example, coolant or moderator and causing extremely rapid generation of steam. The pressure rise within the containment could threaten integrity if rupture disks could not relieve the stress.

Exposed flammable substances could licese, but there are few, if any, flammable substances within the containment. Another theory, called an “alpha mode” failure by the Rasmussen WASH study, asserted steam could produce enough pressure to blow the head off reaktor 6 license free reactor pressure vessel Reakktor. The containment could be threatened if http://replace.me/18190.txt RPV head collided with it.

The WASH report was replaced by better-based [ original research? Bythere were doubts about the ability of the emergency cooling systems of a nuclear reactor to prevent a loss-of-coolant accident and the consequent meltdown of the fuel core; the subject proved popular in the technical and the popular presses. The hypothesis derived from a report by a group of nuclear physicists, headed by W.

It has not been determined to what extent a molten mass can melt through a structure although that was tested in the loss-of-fluid-test reactor described in Test Area North ‘s fact sheet [20]. The Three Mile Island accident provided real-life experience with an actual molten core: the corium failed to melt through the reactor pressure vessel after over six hours of exposure due to dilution of the melt by the control rods and other reactor internals, validating the emphasis on defense in depth against core damage incidents.

Other types of reactors have different capabilities reaktor 6 license free safety profiles than the LWR does. Advanced varieties of several of these reactors have the potential to be inherently safe. The first is the bulk heavy-water moderator a separate system from the reaktor 6 license freeand the second is the light-water-filled shield tank or calandria vault.

These backup heat sinks are sufficient lixense prevent either the fuel meltdown in the first place using the moderator heat sinkor the breaching of the core vessel should reaktor 6 license free moderator eventually boil off using the shield tank heat sink. One type of Western reactor, known as the advanced gas-cooled reactor or AGRbuilt by the United Kingdom, is not very vulnerable to loss-of-cooling accidents or to core damage except in the most extreme of circumstances.

By virtue of the relatively inert reaktor 6 license free carbon dioxidethe large volume and high pressure of the coolant, and raektor relatively high heat transfer efficiency of the reactor, the time frame for core damage in the event of a limiting fault is measured in days. Restoration of some means of coolant flow will prevent core damage from occurring. Other types of highly advanced gas cooled reactors, generally known as high-temperature gas-cooled reactors HTGRs such as the Japanese High Temperature Test Reactor and the United States’ Very High Temperature Reactorare inherently safe, meaning that licehse or other forms of core damage are physically impossible, due to the structure of the core, which consists of hexagonal prismatic reaktor 6 license free of silicon carbide reinforced graphite infused with TRISO or QUADRISO pellets of uranium, thorium, or mixed oxide buried underground in a helium-filled steel pressure vessel within a concrete containment.

Though this type of reactor is not susceptible to meltdown, additional capabilities of heat removal are provided by using regular atmospheric airflow as a means of backup heat removal, by having it pass through a heat reaktor 6 license free and rising into the atmosphere due to convectionachieving full residual heat removal.

This reactor will use a gas as a coolant, which can then be used for process heat such as in hydrogen production or for the driving of gas turbines and the generation of electricity.

A prototype of a very similar type of reactor has been built by the ChineseHTRand has worked beyond researchers’ expectations, leading the Chinese to announce plans to build a pair of follow-on, full-scale MWe, inherently safe, power frde reactors based on the same concept. See Nuclear перейти на источник in the People’s Republic of China for more information. Recently heavy liquid metal, such as lead or lead-bismuth, has been proposed as a reactor coolant.

The PIUS process inherent ultimate safety designs, originally engineered by the Swedes in the late s and early s, are LWRs that by virtue of their design are resistant to core damage. No fee have ever been built. Reaktor 6 license free reactors, including the Deployable Electrical Energy Reactora larger-scale mobile version of the TRIGA for power generation in disaster areas and on military reaktor 6 license free, and the TRIGA Power System, a small reaktor 6 license free plant and heat source for small and remote community use, have been put forward by interested engineers, and share the safety characteristics of the TRIGA due to the uranium zirconium hydride fuel used.

The Hydrogen Moderated Self-regulating Nuclear Teaktor Modulea reactor that uses uranium hydride as a moderator and fuel, similar in chemistry and safety to the TRIGA, also possesses these extreme safety and stability characteristics, and has reaktor 6 license free a good deal of interest in recent times. The liquid fluoride thorium reactor is designed to naturally have its core in a molten state, as a eutectic mix of thorium and fluorine salts. As such, a molten core is reflective of the normal and safe state of operation of this reactor type.

In the event the reaktor 6 license free overheats, a metal plug will reaktor 6 license free, and the molten salt core arcsoft webcam companion free download 10 drain into tanks where it will cool in a non-critical configuration. Since the core is liquid, and already melted, it cannot be damaged. Advanced liquid metal reactors, such as the U.

Soviet-designed RBMK reactors Reaktor Bolshoy Moshchnosti Kanalnyyreaktor 6 license free only in Russia and other post-Soviet states and now shut down everywhere except Russia, do not have containment buildings, are naturally unstable tending to dangerous power fluctuationsand have emergency cooling systems ECCS considered grossly inadequate by Western safety standards.

RBMK emergency core cooling systems only have one division and little redundancy within that division.

The liquid fluoride thorium reactor LFTR ; often pronounced lifter is a type of molten salt reactor. LFTRs use the thorium fuel cycle with a fluoride -based, molten, liquid salt for fuel.

In a typical design, the liquid is pumped between a critical core and an external heat exchanger where the heat is transferred to a nonradioactive secondary salt. The secondary salt then transfers its heat to a steam turbine or closed-cycle gas turbine. Molten-salt-fueled reactors MSRs supply the nuclear fuel mixed into a molten salt. They should not be confused with designs that use a molten salt for cooling only fluoride high-temperature reactors, FHRs and still have a solid fuel.

LFTRs are defined by the use of fluoride fuel salts and the breeding of thorium into uranium in the thermal neutron spectrum. The LFTR has recently been the subject of a renewed interest worldwide.

LFTRs differ from other power reactors in almost every aspect: they use thorium that is turned into uranium, instead of using uranium directly; they are refueled by pumping without shutdown. These distinctive characteristics give rise to many potential advantages, as well as design challenges.

By , eight years after the discovery of nuclear fission , three fissile isotopes had been publicly identified for use as nuclear fuel : [6] [7]. Th, U and U are primordial nuclides , having existed in their current form for over 4. For technical and historical [11] reasons, the three are each associated with different reactor types.

U is the world’s primary nuclear fuel and is usually used in light water reactors. Alvin M. At ORNL, two prototype molten salt reactors were successfully designed, constructed and operated. Both test reactors used liquid fluoride fuel salts. In a nuclear power reactor , there are two types of fuel. The first is fissile material, which splits when hit by neutrons , releasing a large amount of energy and also releasing two or three new neutrons.

These can split more fissile material, resulting in a continued chain reaction. Examples of fissile fuels are U, U and Pu The second type of fuel is called fertile. Examples of fertile fuel are Th mined thorium and U mined uranium. In order to become fissile these nuclides must first absorb a neutron that’s been produced in the process of fission, to become Th and U respectively.

After two sequential beta decays , they transmute into fissile isotopes U and Pu respectively. This process is called breeding. All reactors breed some fuel this way, [17] but today’s solid fueled thermal reactors don’t breed enough new fuel from the fertile to make up for the amount of fissile they consume.

This is because today’s reactors use the mined uranium-plutonium cycle in a moderated neutron spectrum. Such a fuel cycle, using slowed down neutrons, gives back less than 2 new neutrons from fissioning the bred plutonium. Since 1 neutron is required to sustain the fission reaction, this leaves a budget of less than 1 neutron per fission to breed new fuel.

In addition, the materials in the core such as metals, moderators and fission products absorb some neutrons, leaving too few neutrons to breed enough fuel to continue operating the reactor. As a consequence they must add new fissile fuel periodically and swap out some of the old fuel to make room for the new fuel.

In a reactor that breeds at least as much new fuel as it consumes, it is not necessary to add new fissile fuel. Only new fertile fuel is added, which breeds to fissile inside the reactor. In addition the fission products need to be removed.

This type of reactor is called a breeder reactor. If it breeds just as much new fissile from fertile to keep operating indefinitely, it is called a break-even breeder or isobreeder. A LFTR is usually designed as a breeder reactor: thorium goes in, fission products come out. Reactors that use the uranium-plutonium fuel cycle require fast reactors to sustain breeding, because only with fast moving neutrons does the fission process provide more than 2 neutrons per fission.

With thorium, it is possible to breed using a thermal reactor. This was proven to work in the Shippingport Atomic Power Station , whose final fuel load bred slightly more fissile from thorium than it consumed, despite being a fairly standard light water reactor. Thermal reactors require less of the expensive fissile fuel to start, but are more sensitive to fission products left in the core. There are two ways to configure a breeder reactor to do the required breeding.

One can place the fertile and fissile fuel together, so breeding and splitting occurs in the same place. Alternatively, fissile and fertile can be separated. The latter is known as core-and-blanket, because a fissile core produces the heat and neutrons while a separate blanket does all the breeding. Oak Ridge investigated both ways to make a breeder for their molten salt breeder reactor.

Because the fuel is liquid, they are called the “single fluid” and “two fluid” thorium thermal breeder molten salt reactors. The one-fluid design includes a large reactor vessel filled with fluoride salt containing thorium and uranium. Graphite rods immersed in the salt function as a moderator and to guide the flow of salt. In the ORNL MSBR molten salt breeder reactor design [18] a reduced amount of graphite near the edge of the reactor core would make the outer region under-moderated, and increased the capture of neutrons there by the thorium.

With this arrangement, most of the neutrons were generated at some distance from the reactor boundary, and reduced the neutron leakage to an acceptable level.

In a breeder configuration, extensive fuel processing was specified to remove fission products from the fuel salt. The MSRE was a core region only prototype reactor. According to estimates of Japanese scientists, a single fluid LFTR program could be achieved through a relatively modest investment of roughly — million dollars over 5—10 years to fund research to fill minor technical gaps and build a small reactor prototype comparable to the MSRE.

The two-fluid design is mechanically more complicated than the “single fluid” reactor design. The “two fluid” reactor has a high-neutron-density core that burns uranium from the thorium fuel cycle. A separate blanket of thorium salt absorbs neutrons and slowly converts its thorium to protactinium Protactinium can be left in the blanket region where neutron flux is lower, so that it slowly decays to U fissile fuel, [23] rather than capture neutrons.

This bred fissile U can be recovered by injecting additional fluorine to create uranium hexafluoride, a gas which can be captured as it comes out of solution. Once reduced again to uranium tetrafluoride, a solid, it can be mixed into the core salt medium to fission. The core’s salt is also purified, first by fluorination to remove uranium, then vacuum distillation to remove and reuse the carrier salts.

The still bottoms left after the distillation are the fission products waste of a LFTR. One weakness of the two-fluid design is the necessity of periodically replacing the core-blanket barrier due to fast neutron damage.

The effect of neutron radiation on graphite is to slowly shrink and then swell it, causing an increase in porosity and a deterioration in physical properties. Another weakness of the two-fluid design is its complex plumbing. ORNL thought a complex interleaving of core and blanket tubes was necessary to achieve a high power level with acceptably low power density. However, more recent research has questioned the need for ORNL’s complex interleaving graphite tubing, suggesting a simple elongated tube-in-shell reactor that would allow high power output without complex tubing, accommodate thermal expansion, and permit tube replacement.

A two fluid reactor that has thorium in the fuel salt is sometimes called a “one and a half fluid” reactor, or 1. Like the 1 fluid reactor, it has thorium in the fuel salt, which complicates the fuel processing. And yet, like the 2 fluid reactor, it can use a highly effective separate blanket to absorb neutrons that leak from the core. The added disadvantage of keeping the fluids separate using a barrier remains, but with thorium present in the fuel salt there are fewer neutrons that must pass through this barrier into the blanket fluid.

This results in less damage to the barrier. Any leak in the barrier would also be of lower consequence, as the processing system must already deal with thorium in the core. The main design question when deciding between a one and a half or two fluid LFTR is whether a more complicated reprocessing or a more demanding structural barrier will be easier to solve.

In addition to electricity generation , concentrated thermal energy from the high-temperature LFTR can be used as high-grade industrial process heat for many uses, such as ammonia production with the Haber process or thermal Hydrogen production by water splitting, eliminating the efficiency loss of first converting to electricity. The Rankine cycle is the most basic thermodynamic power cycle.

The simplest cycle consists of a steam generator , a turbine, a condenser, and a pump. The working fluid is usually water. A Rankine power conversion system coupled to a LFTR could take advantage of increased steam temperature to improve its thermal efficiency.

The Brayton cycle generator has a much smaller footprint than the Rankine cycle, lower cost and higher thermal efficiency, but requires higher operating temperatures. It is therefore particularly suitable for use with a LFTR. The working gas can be helium, nitrogen, or carbon dioxide. The low-pressure warm gas is cooled in an ambient cooler. The low-pressure cold gas is compressed to the high-pressure of the system. The high-pressure working gas is expanded in a turbine to produce power.

Often the turbine and the compressor are mechanically connected through a single shaft. A Brayton cycle heat engine can operate at lower pressure with wider diameter piping.

The LFTR needs a mechanism to remove the fission products from the fuel. Fission products left in the reactor absorb neutrons and thus reduce neutron economy. This is especially important in the thorium fuel cycle with few spare neutrons and a thermal neutron spectrum, where absorption is strong.

The minimum requirement is to recover the valuable fissile material from used fuel. Removal of fission products is similar to reprocessing of solid fuel elements; by chemical or physical means, the valuable fissile fuel is separated from the waste fission products. Ideally the fertile fuel thorium or U and other fuel components e. However, for economic reasons they may also end up in the waste.

On site processing is planned to work continuously, cleaning a small fraction of the salt every day and sending it back to the reactor. There is no need to make the fuel salt very clean; the purpose is to keep the concentration of fission products and other impurities e. The concentrations of some of the rare earth elements must be especially kept low, as they have a large absorption cross section.

Some other elements with a small cross section like Cs or Zr may accumulate over years of operation before they are removed.

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The two sub-assemblies are joined with a cylinder at the center of the assembly; during the operation of the reactor, this dead space without fuel lowers the neutron flux in the central plane of the reactor. The total mass of uranium in the fuel assembly is The total length of the fuel assembly is In addition to the regular fuel assemblies, there are instrumented ones, containing neutron flux detectors in the central carrier.

In this case, the rod is replaced with a tube with wall thickness of 2. The refueling machine is mounted on a gantry crane and remotely controlled. The fuel assemblies can be replaced without shutting down the reactor, a factor significant for production of weapon-grade plutonium and, in a civilian context, for better reactor uptime. When a fuel assembly has to be replaced, the machine is positioned above the fuel channel: then it mates to the latter, equalizes pressure within, pulls the rod, and inserts a fresh one.

The spent rod is then placed in a cooling pond. The capacity of the refueling machine with the reactor at nominal power level is two fuel assemblies per day, with peak capacity of five per day.

The total amount of fuel under stationary conditions is tons. Most of the reactor control rods are inserted from above; 24 shortened rods are inserted from below and are used to augment the axial power distribution control of the core.

With the exception of 12 automatic rods, the control rods have a 4. The role of the graphite section, known as “displacer”, is to enhance the difference between the neutron flux attenuation levels of inserted and retracted rods, as the graphite displaces water that would otherwise act as a neutron absorber, although much weaker than boron carbide; a control rod channel filled with graphite absorbs fewer neutrons than when filled with water, so the difference between inserted and retracted control rod is increased.

When the control rod is fully retracted, the graphite displacer is located in the middle of the core height, with 1. The displacement of water in the lower 1. This “positive scram” effect was discovered in at the Ignalina Nuclear Power Plant. The narrow space between the rod and its channel hinders water flow around the rods during their movement and acts as a fluid damper, which is the primary cause of their slow insertion time nominally 18—21 seconds for the reactor control and protection system rods, or about 0.

After the Chernobyl disaster, the control rod servos on other RBMK reactors were exchanged to allow faster rod movements, and even faster movement was achieved by cooling of the control rod channels by a thin layer of water between an inner jacket and the Zircaloy tube of the channel while letting the rods themselves move in gas. The division of the control rods between manual and emergency protection groups was arbitrary; the rods could be reassigned from one system to another during reactor operation without technical or organizational problems.

Additional static boron-based absorbers are inserted into the core when it is loaded with fresh fuel. About absorbers are added during initial core loading.

These absorbers are gradually removed with increasing burnup. The reactor’s void coefficient depends on the core content; it ranges from negative with all the initial absorbers to positive when they are all removed. The moisture and temperature of the outlet gas is monitored; an increase of them is an indicator of a coolant leak. The reactor has two independent cooling circuits, each having four main circulating pumps three operating, one standby that service one half of the reactor.

The cooling water is fed to the reactor through lower water lines to a common pressure header one for each cooling circuit , which is split to 22 group distribution headers, each feeding 38—41 pressure channels through the core, where the coolant boils.

The mixture of steam and water is led by the upper steam lines, one for each pressure channel, from the reactor top to the steam separators , pairs of thick horizontal drums located in side compartments above the reactor top; each has 2. The resulting feedwater is led to the steam separators by feedwater pumps and mixed with water from them at their outlets.

From the bottom of the steam separators, the feedwater is led by 12 downpipes from each separator to the suction headers of the main circulation pumps, and back into the reactor.

The turbine consists of one high-pressure rotor cylinder and four low-pressure ones. Five low-pressure separators-preheaters are used to heat steam with fresh steam before being fed to the next stage of the turbine. The uncondensed steam is fed into a condenser, mixed with condensate from the separators, fed by the first-stage condensate pump to a chemical ion-exchange purifier, then by a second-stage condensate pump to four deaerators where dissolved and entrained gases are removed; deaerators also serve as storage tanks for feedwater.

Each of the pressure channels in the core has its own flow control valve so that the temperature distribution in the reactor core can be optimized. Each channel has a ball type flow meter. With few absorbers in the reactor core, such as during the Chernobyl accident, the positive void coefficient of the reactor makes the reactor very sensitive to the feedwater temperature. Bubbles of boiling water lead to increased power, which in turn increases the formation of bubbles.

The water is kept below the saturation temperature to prevent film boiling and the associated drop in heat transfer rate. The reactor is tripped in cases of high or low water level in the steam separators with two selectable low-level thresholds ; high steam pressure; low feedwater flow; loss of two main coolant pumps on either side.

The level of water in the steam separator is mainly controlled by the feedwater supply, with the deaerator tanks serving as a water reservoir. The reactor is equipped with an emergency core cooling system ECCS , consisting of dedicated water reserve tank, hydraulic accumulators, and pumps. ECCS piping is integrated with the normal reactor cooling system. The ECCS has three systems, connected to the coolant system headers.

In case of damage, the first ECCS subsystem provides cooling for up to seconds to the damaged half of the coolant circuit the other half is cooled by the main circulation pumps , and the other two subsystems then handle long-term cooling of the reactor. The short-term ECCS subsystem consists of two groups of six accumulator tanks, containing water blanketed with nitrogen under pressure of 10 megapascals 1, psi , connected by fast-acting valves to the reactor.

The third group is a set of electrical pumps drawing water from the deaerators. The short-term pumps can be powered by the spindown of the main turbogenerators.

ECCS for long-term cooling of the damaged circuit consists of three pairs of electrical pumps, drawing water from the pressure suppression pools; the water is cooled by the plant service water by means of heat exchangers in the suction lines. Each pair is able to supply half of the maximum coolant flow. ECCS for long-term cooling of the intact circuit consists of three separate pumps drawing water from the condensate storage tanks, each able to supply half of the maximum flow.

Some valves that require uninterrupted power are also backed up by batteries. The distribution of power density in the reactor is measured by ionization chambers located inside and outside the core. The physical power density distribution control system PPDDCS has sensors inside the core; the reactor control and protection system RCPS uses sensors in the core and in the lateral biological shield tank.

The external sensors in the tank are located around the reactor middle plane, therefore do not indicate axial power distribution nor information about the power in the central part of the core.

There are over radial and 12 axial power distribution monitors, employing self-powered detectors. Reactivity meters and removable startup chambers are used for monitoring of reactor startup. Total reactor power is recorded as the sum of the currents of the lateral ionization chambers. The moisture and temperature of the gas circulating in the channels is monitored by the pressure tube integrity monitoring system.

Without the automatic systems and relying only on the lateral ionization chambers, control of the reactor becomes very difficult; the operators do not have sufficient data to control the reactor reliably and have to rely on their intuition. During startup of a reactor with a poison-free core this lack of information can be manageable because the reactor behaves predictably, but a non-uniformly poisoned core can cause large nonhomogenities of power distribution, with potentially catastrophic results.

The reactor emergency protection system EPS was designed to shut down the reactor when its operational parameters are exceeded.

However, the slow insertion speed of the control rods, together with their design causing localized positive reactivity as the displacer moves through the lower part of the core, created a number of possible situations where initiation of the EPS could itself cause or aggravate a reactor runaway. Its purpose was to assist the operator with steady-state control of the reactor.

Ten to fifteen minutes were required to cycle through all the measurements and calculate the results. SKALA could not control the reactor, instead it only made recommendations to the operators, and it used s computer technology. The operators could disable some safety systems, reset or suppress some alarm signals, and bypass automatic scram , by attaching patch cables to accessible terminals.

This practice was allowed under some circumstances. The reactor is equipped with a fuel rod leak detector. A scintillation counter detector, sensitive to energies of short-lived fission products, is mounted on a special dolly and moved over the outlets of the fuel channels, issuing an alert if increased radioactivity is detected in the steam-water flow.

In RBMK control rooms there are two large panels or mimic displays representing a top view of the reactor. One display is made up mostly or completely in first generation RBMKs of colored dials or rod position indicators: these dials represent the position of the control rods inside the reactor and the color of the housing of the dials matches that of the control rods, whose colors correspond to their function, for example, red for automatic control rods.

Nuclear Engineering and Design. San Francisco, CA. Huffington Post. ZME Science. Retrieved 12 August Discover Magazine.

Retrieved 22 January Pittsburgh Press. Retrieved 18 October The Tuscaloosa News. American Scientist. Archived from the original PDF on 8 December Nature Geoscience. Bibcode : NatGe Argonne’s Nuclear Science and Technology Legacy. Argonne National Laboratory. Mountain View, CA. Archived from the original PDF on 12 December Oak Ridge National Laboratory.

Nuclear Science and Engineering. Archived from the original on 4 June Physics Today. Bibcode : PhT ISBN Archived from the original on 16 September Retrieved 12 November World Nuclear Association. March Retrieved 28 June The most common isotope formed in a typical nuclear reactor is the fissile Pu isotope, formed by neutron capture from U followed by beta decay , and which yields much the same energy as the fission of U Well over half of the plutonium created in the reactor core is consumed in situ and is responsible for about one third of the total heat output of a light water reactor LWR.

August Nuclear Applications and Technology. November Energy Conversion and Management. June Mechanical Engineering. Retrieved 24 October Idaho National Laboratory. Archived from the original PDF on 8 August Retrieved 4 May Enel Green Power. Archived from the original PDF on 29 October Retrieved 7 April S2CID Archived from the original PDF on 22 January Archived from the original PDF on 15 May Bibcode : EnST PMID Progress in Nuclear Energy.

Archived from the original PDF on 19 January Archived from the original PDF on 26 September Archived from the original PDF on 21 October Conceptual design characteristics of a denatured molten-salt reactor with once-through fueling PDF. Archived from the original PDF on 14 January Retrieved 22 November Retrieved 3 August Retrieved 26 January March—April Europhysics News.

Bibcode : ENews.. Archived from the original PDF on 5 April Retrieved on 24 April Archived from the original PDF on 26 April Archived from the original PDF on 11 August Flibe Energy. Archived from the original on 28 June Platinum Metals Review.

International Atomic Energy Agency. Retrieved 27 October University of Chicago. World Nuclear. The test production phase should complete in December , when regular electricity production should start. The first license application for the third unit was made in December [28] and the date of the unit’s entry into service was estimated to be In July TVO announced that the unit would not go into service before , [14] [29] five years after the original estimate.

In a statement, the operator said it was “not pleased with the situation” although solutions to various problems were being found and work was “progressing”, and that it was waiting for a new launch date from Areva and Siemens. According to Kauppalehti , the estimated opening was delayed until — The delay was caused by slower than expected modification works.

The delays have been due to various problems with planning, supervision, and workmanship, [14] and have been the subject of an inquiry by STUK , the Finnish nuclear safety regulator. Later, it was found that subcontractors had provided heavy forgings that were not up to project standards and which had to be re-cast. An apparent problem constructing the reactor’s unique double-containment structure also caused delays, as the welders had not been given proper instructions. In , Petteri Tiippana, the director of STUK’s nuclear power plant division, told the BBC that it was difficult to deliver nuclear power plant projects on schedule because builders were not used to working to the exacting standards required on nuclear construction sites, since so few new reactors had been built in recent years.

Construction of the turbine succeeded better under the responsibility of Siemens. Installations of the main turbine equipment were completed about one year behind the original schedule. However, as of , the construction of the EPR in France is ten years behind schedule. OL3 is expected to produce an additional 12,, GWh annually. In , professor Stephen Thomas wrote, “Olkiluoto has become an example of all that can go wrong in economic terms with new reactors,” and that Areva and the TVO “are in bitter dispute over who will bear the cost overruns and there is a real risk now that the utility will default.

The delays and cost overruns have had knock-on effects in other countries. The construction workforce includes about 3, employees from companies. In it was reported that one Bulgarian contracting firm is owned by the mafia, and that Bulgarian workers have been required to pay weekly protection fees to the mafia , wages have been unpaid, employees have been told not to join a union and that employers also reneged on social security payments. The decision was approved by the parliament on 1 July In September , with unit 3 still unfinished, the Finnish government rejected TVO’s request for time extension of the unit 4 decision-in-principle.

Economic Affairs Minister Jan Vapaavuori referred to the long delay of the 3rd reactor and to unsatisfactory assurances by TVO that the 4th unit would ever be built.

Nevertheless PM Stubb stated that the rejection didn’t spell the end for the OL4 project, and that TVO would have the opportunity to apply for a construction license before the decision-in-principle expires in June In June TVO decided not to apply for a construction permit for the Olkiluoto 4 unit because of delays with the unit 3, however saying they are prepared to file for a new decision-in-principle later.

The Onkalo spent nuclear fuel repository is a deep geological repository for the final disposal of spent nuclear fuel, the first such repository in the world. It is currently under construction at the Olkiluoto plant by the company Posiva , owned by the nuclear power plant operators Fortum and TVO.

The power plant hosts the northernmost vineyard in the world, a 0. An incident occurred at unit 2 on 10 December at Because of a valve repair work, excessively hot water flowed to the reactor water clean-up system filters. The hot water dissolved materials from the filters. When the clean-up system was restarted, the dissolved materials flowed to the reactor core, where they became radioactive.

This caused the radiation levels in the steam line to rise momentary 3—4 times higher than the normal level. The increase of the radiation level activated safety systems, which operated as planned and triggered reactor scram , closed containment isolation valves, and started the containment spray system.

The operators followed procedures and declared a site area emergency at There was no radioactive release to the environment, and the workers were not exposed to radiation. In April a turbine steam condenser of unit 1 had a small seawater leak, at a rate of two litres per hour. According to the operator, the leak forced to limit the plant output down to MW, but was not serious and was to be repaired in a day.

From Wikipedia, the free encyclopedia. Nuclear power plant in Eurajoki, Finland. Main article: Onkalo spent nuclear fuel repository. Finland portal Energy portal Nuclear technology portal. List of nuclear reactors Finland Hanhikivi Nuclear Power Plant Nuclear engineering Nuclear power in Finland Onkalo spent nuclear fuel repository Into Eternity , a documentary about the construction of a Finnish waste depository Journey to the Safest Place on Earth , a documentary about the urgent need for safe depositories.

Energy Storage News. Archived from the original on 16 June Retrieved 28 August The goal is to recycle tonnes by The United States Enrichment Corporation has been involved in the disposition of a portion of the Through the U. Countries that had enrichment programs in the past include Libya and South Africa, although Libya’s facility was never operational.

Retrieved 5 February Nuclear Energy Today. OECD Publishing. ISBN Proceedings of international forum on illegal nuclear traffic. Archived from the original PDF on 22 July June Retrieved 1 July Princeton University. Retrieved 18 April March Oak Ridge National Laboratories. Archived from the original PDF on 2 November Retrieved 30 October Nuclear Weapons FAQ. Retrieved 2 October Retrieved 19 December The enrichment of the pin and of one of the hemispheres was Retrieved 26 January Von Hippel; Laura H.

The basic design of pebble-bed reactors features spherical fuel elements called pebbles. These tennis ball-sized pebbles (approx. cm or in in diameter) are made of pyrolytic graphite (which acts as the moderator), and they contain thousands of micro-fuel particles called TRISO particles. These TRISO fuel particles consist of a fissile material (such as U) surrounded . A fluidized bed reactor (FBR) is a type of reactor device that can be used to carry out a variety of multiphase chemical reactions. In this type of reactor, a fluid (gas or liquid) is passed through a solid granular material (usually a catalyst) at high enough speeds to suspend the solid and cause it to behave as though it were a replace.me process, known as fluidization, imparts many. The Flamanville Nuclear Power Plant is located at Flamanville, Manche, France on the Cotentin replace.me power plant houses two pressurized water reactors (PWRs) that produce GW e each and came into service in and , respectively. It produced TWh in , which amounted to 4% of the electricity production in France. In this figure was about %. Moving bed biofilm reactor (MBBR) is a type of wastewater treatment process that was first invented by Prof. Hallvard Ødegaard at Norwegian University of Science and Technology in the late s. It was commercialized by Kaldnes Miljöteknologi (now called AnoxKaldnes and owned by Veolia Water Technologies).There are over wastewater treatment systems (both .

Enriched uranium is a type of uranium in which the percent composition of uranium written U has been increased through the process of isotope separation. Naturally occurring uranium is composed of three major isotopes: uranium U with Enriched uranium is a critical component for both civil nuclear power generation and military nuclear weapons. The International Atomic Energy Agency attempts to monitor and control enriched uranium supplies and processes in its efforts to ensure nuclear power generation safety and curb nuclear weapons proliferation.

There are about 2, tonnes of highly enriched uranium in the world, [3] produced mostly for nuclear power , nuclear weapons, naval propulsion , and smaller quantities for research reactors. The U remaining after enrichment is known as depleted uranium DU , and is considerably less radioactive than even natural uranium, though still very dense.

Depleted uranium is used as a radiation shielding material and for armor-penetrating weapons. Uranium as it is taken directly from the Earth is not suitable as fuel for most nuclear reactors and requires additional processes to make it usable CANDU design is a notable exception. Uranium is mined either underground or in an open pit depending on the depth at which it is found.

After the uranium ore is mined, it must go through a milling process to extract the uranium from the ore. After the milling process is complete, the uranium must next undergo a process of conversion, “to either uranium dioxide , which can be used as the fuel for those types of reactors that do not require enriched uranium, or into uranium hexafluoride , which can be enriched to produce fuel for the majority of types of reactors”.

Most nuclear reactors require enriched uranium, which is uranium with higher concentrations of U ranging between 3. There are two commercial enrichment processes: gaseous diffusion and gas centrifugation. Both enrichment processes involve the use of uranium hexafluoride and produce enriched uranium oxide. Reprocessed uranium RepU is a product of nuclear fuel cycles involving nuclear reprocessing of spent fuel.

RepU recovered from light water reactor LWR spent fuel typically contains slightly more U than natural uranium , and therefore could be used to fuel reactors that customarily use natural uranium as fuel, such as CANDU reactors. It also contains the undesirable isotope uranium , which undergoes neutron capture , wasting neutrons and requiring higher U enrichment and creating neptunium , which would be one of the more mobile and troublesome radionuclides in deep geological repository disposal of nuclear waste.

Neutron reflectors, compressing the fissile core via implosion, fusion boosting , and “tamping”, which slows the expansion of the fissioning core with inertia, allow nuclear weapon designs that use less than what would be one bare-sphere critical mass at normal density. The presence of too much of the U isotope inhibits the runaway nuclear chain reaction that is responsible for the weapon’s power.

For the secondary of a large nuclear weapon, the higher critical mass of less-enriched uranium can be an advantage as it allows the core at explosion time to contain a larger amount of fuel. The Fermi-1 commercial fast reactor prototype used HEU with Significant quantities of HEU are used in the production of medical isotopes , for example molybdenum for technetiumm generators.

Isotope separation is difficult because two isotopes of the same element have nearly identical chemical properties, and can only be separated gradually using small mass differences. This problem is compounded because uranium is rarely separated in its atomic form, but instead as a compound UF 6 is only 0.

A cascade of identical stages produces successively higher concentrations of U. Each stage passes a slightly more concentrated product to the next stage and returns a slightly less concentrated residue to the previous stage. Gaseous diffusion is a technology used to produce enriched uranium by forcing gaseous uranium hexafluoride hex through semi-permeable membranes. This produces a slight separation between the molecules containing U and U.

Thermal diffusion uses the transfer of heat across a thin liquid or gas to accomplish isotope separation. The process exploits the fact that the lighter U gas molecules will diffuse toward a hot surface, and the heavier U gas molecules will diffuse toward a cold surface. It was abandoned in favor of gaseous diffusion. The gas centrifuge process uses a large number of rotating cylinders in series and parallel formations.

Each cylinder’s rotation creates a strong centripetal force so that the heavier gas molecules containing U move tangentially toward the outside of the cylinder and the lighter gas molecules rich in U collect closer to the center.

It requires much less energy to achieve the same separation than the older gaseous diffusion process, which it has largely replaced and so is the current method of choice and is termed second generation. It has a separation factor per stage of 1. The Zippe-type centrifuge is an improvement on the standard gas centrifuge, the primary difference being the use of heat.

Laser processes promise lower energy inputs, lower capital costs and lower tails assays, hence significant economic advantages.

The technique uses lasers tuned to frequencies that ionize U atoms and no others. The positively charged U ions are then attracted to a negatively charged plate and collected. Molecular laser isotope separation uses an infrared laser directed at UF 6 , exciting molecules that contain a U atom.

A second laser frees a fluorine atom, leaving uranium pentafluoride , which then precipitates out of the gas. Separation of isotopes by laser excitation is an Australian development that also uses UF 6. After a protracted development process involving U. SILEX has been projected to be an order of magnitude more efficient than existing production techniques but again, the exact figure is classified.

Aerodynamic enrichment processes include the Becker jet nozzle techniques developed by E. Becker and associates using the LIGA process and the vortex tube separation process. These aerodynamic separation processes depend upon diffusion driven by pressure gradients, as does the gas centrifuge.

They in general have the disadvantage of requiring complex systems of cascading of individual separating elements to minimize energy consumption. In effect, aerodynamic processes can be considered as non-rotating centrifuges. Enhancement of the centrifugal forces is achieved by dilution of UF 6 with hydrogen or helium as a carrier gas achieving a much higher flow velocity for the gas than could be obtained using pure uranium hexafluoride.

The Uranium Enrichment Corporation of South Africa UCOR developed and deployed the continuous Helikon vortex separation cascade for high production rate low-enrichment and the substantially different semi-batch Pelsakon low production rate high enrichment cascade both using a particular vortex tube separator design, and both embodied in industrial plant.

However all methods have high energy consumption and substantial requirements for removal of waste heat; none is currently still in use.

In the electromagnetic isotope separation process EMIS , metallic uranium is first vaporized, and then ionized to positively charged ions. The cations are then accelerated and subsequently deflected by magnetic fields onto their respective collection targets.

A production-scale mass spectrometer named the Calutron was developed during World War II that provided some of the U used for the Little Boy nuclear bomb, which was dropped over Hiroshima in Properly the term ‘Calutron’ applies to a multistage device arranged in a large oval around a powerful electromagnet. Electromagnetic isotope separation has been largely abandoned in favour of more effective methods.

One chemical process has been demonstrated to pilot plant stage but not used for production. An ion-exchange process was developed by the Asahi Chemical Company in Japan that applies similar chemistry but effects separation on a proprietary resin ion-exchange column.

Plasma separation process PSP describes a technique that makes use of superconducting magnets and plasma physics. In this process, the principle of ion cyclotron resonance is used to selectively energize the U isotope in a plasma containing a mix of ions. Funding for RCI was drastically reduced in , and the program was suspended around , although RCI is still used for stable isotope separation.

Separative work is not energy. The same amount of separative work will require different amounts of energy depending on the efficiency of the separation technology.

In addition to the separative work units provided by an enrichment facility, the other important parameter to be considered is the mass of natural uranium NU that is needed to yield a desired mass of enriched uranium. As with the number of SWUs, the amount of feed material required will also depend on the level of enrichment desired and upon the amount of U that ends up in the depleted uranium.

However, unlike the number of SWUs required during enrichment, which increases with decreasing levels of U in the depleted stream, the amount of NU needed will decrease with decreasing levels of U that end up in the DU. For example, in the enrichment of LEU for use in a light water reactor it is typical for the enriched stream to contain 3. On the other hand, if the depleted stream had only 0. Because the amount of NU required and the number of SWUs required during enrichment change in opposite directions, if NU is cheap and enrichment services are more expensive, then the operators will typically choose to allow more U to be left in the DU stream whereas if NU is more expensive and enrichment is less so, then they would choose the opposite.

When converting uranium hexafluoride, hex for short to metal,. The opposite of enriching is downblending; surplus HEU can be downblended to LEU to make it suitable for use in commercial nuclear fuel.

High concentrations of U are a byproduct from irradiation in a reactor and may be contained in the HEU, depending on its manufacturing history. The production of U is thus unavoidable in any thermal neutron reactor with U fuel.

HEU reprocessed from nuclear weapons material production reactors with an U assay of approx. While U also absorbs neutrons, it is a fertile material that is turned into fissile U upon neutron absorption. If U absorbs a neutron, the resulting short-lived U beta decays to Np , which is not usable in thermal neutron reactors but can be chemically separated from spent fuel to be disposed of as waste or to be transmutated into Pu for use in nuclear batteries in special reactors.

So, the HEU downblending generally cannot contribute to the waste management problem posed by the existing large stockpiles of depleted uranium. At present, 95 percent of the world’s stocks of depleted uranium remain in secure storage.

From through mid, tonnes of high-enriched uranium enough for 10, warheads was recycled into low-enriched-uranium. The goal is to recycle tonnes by The United States Enrichment Corporation has been involved in the disposition of a portion of the Through the U. Countries that had enrichment programs in the past include Libya and South Africa, although Libya’s facility was never operational. During the Manhattan Project , weapons-grade highly enriched uranium was given the codename oralloy , a shortened version of Oak Ridge alloy, after the location of the plants where the uranium was enriched.

From Wikipedia, the free encyclopedia. Uranium in which isotope separation has been used to increase its proportion of uranium Main article: Reprocessed uranium. Main article: Gaseous diffusion. Main article: Gas centrifuge. Main article: Calutron.

Further information: Separative work units.

The ‘s Aircraft Reactor Experiment was primarily motivated by the compact size that the technique offers, while the ‘s Molten-Salt Reactor Experiment aimed to prove the concept of a nuclear power plant which implements a thorium fuel cycle in a breeder reactor. MSRs are considered safer than conventional reactors because they operate with fuel already in a molten state, and in event of an emergency, the fuel mixture is designed to drain from the core to a containment vessel where it will solidify in fuel drain tanks.

This prevents the uncontrolled nuclear meltdown and associated hydrogen explosions as in the Fukushima nuclear disaster that are at risk in conventional solid-fuel reactors. Another advantage of MSRs is that the gaseous fission products Xe and Kr do not have much solubility in the fuelsalt, [a] and can be safely captured as they bubble out of the molten fuel, [b] rather than increasing the pressure inside the fuel tubes over the life of the fuel, as happens in conventional solid-fuelled reactors.

Relevant design challenges include the corrosivity of hot salts and the changing chemical composition of the salt as it is transmuted by the neutron flux in the reactor core. MSRs offer multiple advantages over conventional nuclear power plants, although for historical reasons they have not been deployed. MSRs, especially those with the fuel dissolved in the salt, differ considerably from conventional reactors. Reactor core pressure can be low and the temperature much higher.

In this respect an MSR is more similar to a liquid metal cooled reactor than to a conventional light water cooled reactor. MSRs are often planned as breeding reactors with a closed fuel cycle—as opposed to the once-through fuel currently used in U.

Safety concepts rely on a negative temperature coefficient of reactivity and a large possible temperature rise to limit reactivity excursions. As an additional method for shutdown, a separate, passively cooled container below the reactor can be included.

In case of problems, and for regular maintenance, the fuel is drained from the reactor. This stops the nuclear reaction and acts as a second cooling system. Neutron-producing accelerators have been proposed for some super-safe subcritical experimental designs.

The temperatures of some proposed designs are high enough to produce process heat for hydrogen production or other chemical reactions. MSRs offer many potential advantages over current light water reactors: [8]. FHRs cannot reprocess fuel easily and have fuel rods that need to be fabricated and validated, requiring up to twenty years [ citation needed ] from project inception.

FHR retains the safety and cost advantages of a low-pressure, high-temperature coolant, also shared by liquid metal cooled reactors. Notably, steam is not created in the core as is present in BWRs , and no large, expensive steel pressure vessel as required for PWRs.

Since it can operate at high temperatures, the conversion of the heat to electricity can use an efficient, lightweight Brayton cycle gas turbine. Much of the current research on FHRs is focused on small, compact heat exchangers that reduce molten salt volumes and associated costs. Molten salts can be highly corrosive and corrosivity increases with temperature. For the primary cooling loop, a material is needed that can withstand corrosion at high temperatures and intense radiation.

However, operating experience is limited. Materials for this temperature range have not been validated, though carbon composites, molybdenum alloys e. A workaround suggested by a private researcher is to use the new beta-titanium Au alloys as this would also allow extreme temperature operation as well as increasing the safety margin.

Fluorine has only one stable isotope 19 F , and does not easily become radioactive under neutron bombardment. Compared to chlorine and other halides, fluorine also absorbs fewer neutrons and slows ” moderates ” neutrons better.

Low- valence fluorides boil at high temperatures, though many pentafluorides and hexafluorides boil at low temperatures. They must be very hot before they break down into their constituent elements. Such molten salts are “chemically stable” when maintained well below their boiling points. Fluoride salts dissolve poorly in water, and do not form burnable hydrogen. Chlorine has two stable isotopes 35 Cl and 37 Cl , as well as a slow-decaying isotope between them which facilitates neutron absorption by 35 Cl.

Chlorides permit fast breeder reactors to be constructed. Much less research has been done on reactor designs using chloride salts. Chlorine, unlike fluorine, must be purified to isolate the heavier stable isotope, 37 Cl , thus reducing production of sulfur tetrachloride that occurs when 35 Cl absorbs a neutron to become 36 Cl , then degrades by beta decay to 36 S.

Lithium must be in the form of purified 7 Li , because 6 Li effectively captures neutrons and produces tritium. Even if pure 7 Li is used, salts containing lithium cause significant tritium production, comparable with heavy water reactors.

Reactor salts are usually close to eutectic mixtures to reduce their melting point. A low melting point simplifies melting the salt at startup and reduces the risk of the salt freezing as it is cooled in the heat exchanger.

Due to the high ” redox window” of fused fluoride salts, the redox potential of the fused salt system can be changed. Fluorine-lithium-beryllium ” FLiBe ” can be used with beryllium additions to lower the redox potential and nearly eliminate corrosion.

However, since beryllium is extremely toxic, special precautions must be engineered into the design to prevent its release into the environment. Many other salts can cause plumbing corrosion, especially if the reactor is hot enough to make highly reactive hydrogen. To date, most research has focused on FLiBe, because lithium and beryllium are reasonably effective moderators and form a eutectic salt mixture with a lower melting point than each of the constituent salts.

Beryllium also performs neutron doubling, improving the neutron economy. This process occurs when the beryllium nucleus emits two neutrons after absorbing a single neutron. Thorium and plutonium fluorides have also been used. Techniques for preparing and handling molten salt were first developed at ORNL. Oxides could result in the deposition of solid particles in reactor operation. Sulfur must be removed because of its corrosive attack on nickel-based alloys at operational temperature. Structural metal such as chromium, nickel, and iron must be removed for corrosion control.

The possibility of online processing can be an MSR advantage. Continuous processing would reduce the inventory of fission products, control corrosion and improve neutron economy by removing fission products with high neutron absorption cross-section, especially xenon. This makes the MSR particularly suited to the neutron-poor thorium fuel cycle.

In some thorium breeding scenarios, the intermediate product protactinium Pa would be removed from the reactor and allowed to decay into highly pure U , an attractive bomb-making material. More modern designs propose to use a lower specific power or a separate thorium breeding blanket.

This dilutes the protactinium to such an extent that few protactinium atoms absorb a second neutron or, via a n, 2n reaction in which an incident neutron is not absorbed but instead knocks a neutron out of the nucleus , generate U.

Because U has a short half-life and its decay chain contains hard gamma emitters, it makes the isotopic mix of uranium less attractive for bomb-making. This benefit would come with the added expense of a larger fissile inventory or a 2-fluid design with a large quantity of blanket salt. The necessary fuel salt reprocessing technology has been demonstrated, but only at laboratory scale.

Reprocessing refers to the chemical separation of fissionable uranium and plutonium from spent fuel. In the United States the regulatory regime has varied dramatically across administrations. A systematic literature review from concludes that there is very limited information on economics and finance of MSRs, with low quality of the information and that cost estimations are uncertain.

In the specific case of the stable salt reactor SSR where the radioactive fuel is contained as a molten salt within fuel pins and the primary circuit is not radioactive, operating costs are likely to be lower.

While many design variants have been proposed, there are three main categories regarding the role of molten salt:. The use of molten salt as fuel and as coolant are independent design choices – the original circulating-fuel-salt MSRE and the more recent static-fuel-salt SSR use salt as fuel and salt as coolant; the DFR uses salt as fuel but metal as coolant; and the FHR has solid fuel but salt as coolant.

MSRs can be burners or breeders. They can be fast or thermal or epithermal. Thermal reactors typically employ a moderator usually graphite to slow the neutrons down and moderate temperature.

They can accept a variety of fuels low-enriched uranium, thorium, depleted uranium , waste products [22] and coolants fluoride, chloride, lithium, beryllium, mixed. Fuel cycle can be either closed or once-through. The reactor can adopt a loop, modular or integral configuration. Variations include:. The molten salt fast reactor MSFR is a proposed design with the fuel dissolved in a fluoride salt coolant.

They have been studied for almost a decade, mainly by calculations and determination of basic physical and chemical properties in the European Union and Russian Federation. When steady state is achieved in a MSFR, there is no longer a need for uranium enrichment facilities.

MSFRs may be breeder reactors. They operate without a moderator in the core such as graphite, so graphite life-span is no longer a problem. This results in a breeder reactor with a fast neutron spectrum that operates in the Thorium fuel cycle. MSFRs contain relatively small initial inventories of U. MSFRs run on liquid fuel with no solid matter inside the core.

This leads to the possibility of reaching specific power that is much higher than reactors using solid fuel. The heat produced goes directly into the heat transfer fluid. In the MSFR, a small amount of molten salt is set aside to be processed for fission product removal and then returned to the reactor. This gives MSFRs the capability of reprocessing the fuel without stopping the reactor. This is very different compared to solid-fueled reactors because they have separate facilities to produce the solid fuel and process spent nuclear fuel.

The MSFR can operate using a large variety of fuel compositions due to its on-line fuel control and flexible fuel processing. The core’s shape is a compact cylinder with a height to diameter ratio of 1 where liquid fluoride fuel salt flows from the bottom to the top. The return circulation of the salt, from top to bottom, is broken up into 16 groups of pumps and heat exchangers located around the core. The fuel salt takes approximately 3 to 4 seconds to complete a full cycle.

At any given time during operation, half of the total fuel salt volume is in the core and the rest is in the external fuel circuit salt collectors, salt-bubble separators, fuel heat exchangers, pumps, salt injectors and pipes. During operation, the fuel salt circulation speed can be adjusted by controlling the power of the pumps in each sector.

The intermediate fluid circulation speed can be adjusted by controlling the power of the intermediate circuit pumps. The temperature of the intermediate fluid in the intermediate exchangers can be managed through the use of a double bypass.

This allows the temperature of the intermediate fluid at the conversion exchanger inlet to be held constant while its temperature is increased in a controlled way at the inlet of the intermediate exchangers. The temperature of the core can be adjusted by varying the proportion of bubbles injected in the core since it reduces the salt density. As a result, it reduces the mean temperature of the fuel salt.

Reaktor 6 license free.Olkiluoto Nuclear Power Plant – Wikipedia

Countries that had enrichment programs in the past include Libya and South Africa, although Libya’s facility was never operational. During the Manhattan Project , weapons-grade highly enriched uranium was given the codename oralloy , a shortened version of Oak Ridge alloy, after the location of the plants where the uranium was enriched. From Wikipedia, the free encyclopedia. Uranium in which isotope separation has been used to increase its proportion of uranium Main article: Reprocessed uranium.

Main article: Gaseous diffusion. Main article: Gas centrifuge. Main article: Calutron. Further information: Separative work units. Retrieved 5 February Nuclear Energy Today. OECD Publishing. ISBN Proceedings of international forum on illegal nuclear traffic. Archived from the original PDF on 22 July June Retrieved 1 July Princeton University. Retrieved 18 April March Oak Ridge National Laboratories.

Archived from the original PDF on 2 November Retrieved 30 October Nuclear Weapons FAQ. Retrieved 2 October Retrieved 19 December The enrichment of the pin and of one of the hemispheres was Retrieved 26 January Von Hippel; Laura H. Kahn December S2CID To produce the same amount of reactor-grade fuel requires a considerably larger number approximately 50, to , of centrifuge units than diffusion units. Silex Ltd. Atomic Insights.

Archived from the original on 28 January The s facility is the last remaining gaseous diffusion uranium enrichment plant in the world.

Retrieved 21 November Standing Committee on Industry and Resources Report. The Parliament of the Commonwealth of Australia. November Retrieved 3 April BBC News. Discover Magazine. Retrieved 22 January Pittsburgh Press. Retrieved 18 October The Tuscaloosa News. American Scientist. Archived from the original PDF on 8 December Nature Geoscience. Bibcode : NatGe Argonne’s Nuclear Science and Technology Legacy. Argonne National Laboratory. Mountain View, CA. Archived from the original PDF on 12 December Oak Ridge National Laboratory.

August Nuclear Applications and Technology. November Energy Conversion and Management. June Mechanical Engineering. Retrieved 24 October Idaho National Laboratory.

Archived from the original PDF on 8 August Retrieved 4 May Enel Green Power. Archived from the original PDF on 29 October Retrieved 7 April S2CID Archived from the original PDF on 22 January Archived from the original PDF on 15 May Bibcode : EnST PMID Progress in Nuclear Energy. Archived from the original PDF on 19 January Archived from the original PDF on 26 September Archived from the original PDF on 21 October Conceptual design characteristics of a denatured molten-salt reactor with once-through fueling PDF.

Archived from the original PDF on 14 January Retrieved 22 November Retrieved 3 August Retrieved 26 January March—April Europhysics News. Bibcode : ENews.. Archived from the original PDF on 5 April Retrieved on 24 April Archived from the original PDF on 26 April Archived from the original PDF on 11 August Flibe Energy. Archived from the original on 28 June Platinum Metals Review. International Atomic Energy Agency.

Retrieved 27 October University of Chicago. World Nuclear. Archived from the original PDF on 1 January Archived from the original PDF on 6 August Archived from the original PDF on 29 June Retrieved 6 June Seoul, Korea. Retrieved 31 August Retrieved 16 October LAB NE Committee on Remediation of Buried and Tank Wastes.

Molten Salt Panel Evaluation of the U. Department of Energy’s alternatives for the removal and disposition of molten salt reactor experiment fluoride salts. National Academies Press.

Boston, Massachusetts: Materials Research Society. Nuclear Engineering and Technology. International Thorium Energy Organisation. Archived from the original on 27 July Wired Science.

Archived from the original on 17 July The Guardian. Weinberg Foundation. Archived from the original on 21 April Retrieved 17 April The Daily Telegraph. Next Big Future. Retrieved 27 June Bibcode : Natur. Archived from the original on 6 April Archived from the original on 10 March The main design features include neutron moderation from graphite, fueling with low-enriched uranium and a compact and replaceable Core-unit.

Decay heat is removed passively using nitrogen with air as an emergency alternative. The latter feature permits the operational simplicity necessary for industrial deployment. Terrestrial completed the first phase of a prelicensing review by the Canadian Nuclear Safety Commission in , which provided a regulatory opinion that the design features are generally safe enough to eventually obtain a license to construct the reactor.

Copenhagen Atomics is a Danish molten salt technology company developing mass manufacturable molten salt reactors. The Copenhagen Atomics Waste Burner is a single-fluid, heavy water moderated, fluoride-based, thermal spectrum and autonomously controlled molten salt reactor.

This is designed to fit inside of a leak-tight, foot, stainless steel shipping container. A molten lithium-7 deuteroxide 7 LiOD moderator version is also being researched.

The reactor utilizes the thorium fuel cycle using separated plutonium from spent nuclear fuel as the initial fissile load for the first generation of reactors, eventually transitioning to a thorium breeder. During operation, the fuel will not be replaced and will burn for the entire year reactor lifetime.

The original MSR concept used the fluid salt to provide the fission materials and also to remove the heat. Thus it had problems with the needed flow speed. Using 2 different fluids in separate circles solves the problem. In , Indian researchers published a MSR design, [67] as an alternative path to thorium-based reactors, according to India’s three-stage nuclear power programme.

A consortium including members from Japan, the U. The project would likely take 20 years to develop a full size reactor, [72] but the project seems to lack funding. It would be fueled by plutonium from reprocessed VVER spent nuclear fuel and fluorides of minor actinides. It is expected to launch in at Mining and Chemical Combine. The Alvin Weinberg Foundation is a British non-profit organization founded in , dedicated to raising awareness about the potential of thorium energy and LFTR.

It was formally launched at the House of Lords on 8 September Weinberg , who pioneered thorium MSR research. Idaho National Laboratory designed [ when? Kirk Sorensen, former NASA scientist and chief nuclear technologist at Teledyne Brown Engineering , is a long-time promoter of the thorium fuel cycle , coining the term liquid fluoride thorium reactor.

It is easier to approve novel military designs than civilian power station designs in the US nuclear regulatory environment.

Transatomic Power pursued what it termed a waste-annihilating molten salt reactor WAMSR , intended to consume existing spent nuclear fuel , [87] from until ceasing operation in and open-sourcing their research. Department of Energy announced plans to build the Molten Chloride Reactor Experiment, the first fast-spectrum salt reactor at the Idaho National Laboratory. From Wikipedia, the free encyclopedia. Type of nuclear reactor cooled by molten material.

Main article: Liquid fluoride thorium reactor. Main article: Stable salt reactor. Main article: Aircraft Reactor Experiment. Main article: Molten-Salt Reactor Experiment. Nuclear technology portal Energy portal Physics portal. Aqueous homogeneous reactor Integral fast reactor Nuclear aircraft Nuclear waste. The fission products that are not soluble e. Xe, Kr are continuously removed from the molten fuel salt, solidified, packaged, and placed in passively cooled storage vaults”.

Charles W. In this design, the gaseous fission byproducts Xe and Kr are separated by Helium sparge into holding tanks, where their radioactivity has decayed, after about a week.

Bibcode : Natur. PMID S2CID Retrieved 10 September Molten-salt reactors are considered to be relatively safe because the fuel is already dissolved in liquid and they operate at lower pressures than do conventional nuclear reactors, which reduces the risk of explosive meltdowns.

File: GenIV. The gas flow continues to a cryogenic gas processing system to separate the gasses, storing stable Xe and radioactive Kr in gas bottles and returning He for reuse as a sweep gas”. AIP Conference Proceedings. Bibcode : AIPC.. OSTI Archived from the original PDF on 28 February Popular Mechanics. Transatomic Power Inc. Archived from the original PDF on 5 July Retrieved 2 June San Francisco, CA. Critical issues of nuclear energy systems employing molten salt fluorides PDF.

Archived from the original PDF on 13 April Retrieved 18 December Forsberg, Charles June Archived from the original PDF on 13 January Retrieved 12 September Progress in Nuclear Energy. The Chemical Engineer. The Molten Salt Reactor option for beneficial use of fissile material from dismantled weapons.

Annual meeting of the American Association for the Advancement of Science: earth science. Retrieved 2 September ISSN Annals of Nuclear Energy. American Scientist. JSTOR ProQuest Circular , U. Nuclear Science and Engineering. Mitchell 22 February Knowable Magazine. ISBN Retrieved 12 November GDP Then? Retrieved 12 February The Technology pork barrel. Brookings Institution.

Retrieved 28 February The Alvin Weinberg Foundation. Archived from the original on 5 March Retrieved 13 June Advanced Reactors with Innovative Fuels. Annual Review of Environment and Resources. Retrieved 25 June Canadian Nuclear Safety Commission. Retrieved 10 November The Guardian.

A breeder reactor is a nuclear reactor that generates more fissile material than it consumes. Breeder reactors achieve this because their neutron economy is high enough to create more fissile fuel than they use, by irradiation of a fertile material, such as uranium or thorium, that is loaded into the reactor along with fissile replace.mers were at first found attractive . A fluidized bed reactor (FBR) is a type of reactor device that can be used to carry out a variety of multiphase chemical reactions. In this type of reactor, a fluid (gas or liquid) is passed through a solid granular material (usually a catalyst) at high enough speeds to suspend the solid and cause it to behave as though it were a replace.me process, known as fluidization, imparts many. The basic design of pebble-bed reactors features spherical fuel elements called pebbles. These tennis ball-sized pebbles (approx. cm or in in diameter) are made of pyrolytic graphite (which acts as the moderator), and they contain thousands of micro-fuel particles called TRISO particles. These TRISO fuel particles consist of a fissile material (such as U) surrounded . The Flamanville Nuclear Power Plant is located at Flamanville, Manche, France on the Cotentin replace.me power plant houses two pressurized water reactors (PWRs) that produce GW e each and came into service in and , respectively. It produced TWh in , which amounted to 4% of the electricity production in France. In this figure was about %.
In electrical engineering, current limiting reactors can reduce short-circuit currents, which result from plant expansions and power source additions, to levels that can be adequately handled by existing distribution equipment. They can also be used in high voltage electric power transmission grids for a similar purpose. In the control of electric motors, current limiting reactors can be . The X Graphite Reactor is a decommissioned nuclear reactor at Oak Ridge National Laboratory in Oak Ridge, replace.mely known as the Clinton Pile and X Pile, it was the world’s second artificial nuclear reactor (after Enrico Fermi’s Chicago Pile-1), and the first designed and built for continuous replace.me was built during World War II as part of the . A breeder reactor is a nuclear reactor that generates more fissile material than it consumes. Breeder reactors achieve this because their neutron economy is high enough to create more fissile fuel than they use, by irradiation of a fertile material, such as uranium or thorium, that is loaded into the reactor along with fissile replace.mers were at first found attractive . The basic design of pebble-bed reactors features spherical fuel elements called pebbles. These tennis ball-sized pebbles (approx. cm or in in diameter) are made of pyrolytic graphite (which acts as the moderator), and they contain thousands of micro-fuel particles called TRISO particles. These TRISO fuel particles consist of a fissile material (such as U) surrounded .

There are two commercial enrichment processes: gaseous diffusion and gas centrifugation. Both enrichment processes involve the use of uranium hexafluoride and produce enriched uranium oxide. Reprocessed uranium RepU is a product of nuclear fuel cycles involving nuclear reprocessing of spent fuel.

Wrapping the weapon’s fissile core in a neutron reflector which is standard on all nuclear explosives can dramatically reduce the critical mass. Because the core was surrounded by a good neutron reflector, at explosion it comprised almost 2. Neutron reflectors, compressing the fissile core via implosion, fusion boosting , and “tamping”, which slows the expansion of the fissioning core with inertia, allow nuclear weapon designs that use less than what would be one bare-sphere critical mass at normal density.

The presence of too much of the U isotope inhibits the runaway nuclear chain reaction that is responsible for the weapon’s power. For the secondary of a large nuclear weapon, the higher critical mass of less-enriched uranium can be an advantage as it allows the core at explosion time to contain a larger amount of fuel. The Fermi-1 commercial fast reactor prototype used HEU with Significant quantities of HEU are used in the production of medical isotopes , for example molybdenum for technetiumm generators.

Isotope separation is difficult because two isotopes of the same element have nearly identical chemical properties, and can only be separated gradually using small mass differences.

This problem is compounded because uranium is rarely separated in its atomic form, but instead as a compound UF 6 is only 0. A cascade of identical stages produces successively higher concentrations of U. Each stage passes a slightly more concentrated product to the next stage and returns a slightly less concentrated residue to the previous stage.

Gaseous diffusion is a technology used to produce enriched uranium by forcing gaseous uranium hexafluoride hex through semi-permeable membranes. This produces a slight separation between the molecules containing U and U. Thermal diffusion uses the transfer of heat across a thin liquid or gas to accomplish isotope separation.

The process exploits the fact that the lighter U gas molecules will diffuse toward a hot surface, and the heavier U gas molecules will diffuse toward a cold surface. It was abandoned in favor of gaseous diffusion. The gas centrifuge process uses a large number of rotating cylinders in series and parallel formations. Each cylinder’s rotation creates a strong centripetal force so that the heavier gas molecules containing U move tangentially toward the outside of the cylinder and the lighter gas molecules rich in U collect closer to the center.

The bottom of the rotating cylinder is heated, producing convection currents that move the U up the cylinder, where it can be collected by scoops. This improved centrifuge design is used commercially by Urenco to produce nuclear fuel and was used by Pakistan in their nuclear weapons program. Laser processes promise lower energy inputs, lower capital costs and lower tails assays, hence significant economic advantages.

Several laser processes have been investigated or are under development. Separation of isotopes by laser excitation SILEX is well developed and is licensed for commercial operation as of Atomic vapor laser isotope separation employs specially tuned lasers [18] to separate isotopes of uranium using selective ionization of hyperfine transitions. The technique uses lasers tuned to frequencies that ionize U atoms and no others. The positively charged U ions are then attracted to a negatively charged plate and collected.

The decision was announced six days before the third anniversary of the accident at Chernobyl World Nuclear Association.

June Archived from the original on June 26, Retrieved March 10, Chernobyl: a technical appraisal: proceedings of the seminar organized by the British Nuclear Energy Society held in London on 3 October London: Thomas Telford Ltd. ISBN Archived from the original on 14 December Retrieved June 27, April 30, Retrieved March 22, Archived from the original on January 31, United Press International.

April 20, Archived from the original on November 14, Retrieved April 1, — via LA Times. Archived from the original on April 11, Retrieved April 1, Archived from the original on January 18, Simon and Schuster. Archived from the original on September 1, Retrieved May 3, — via Google Books. The Legacy of Chernobyl Paperback. First American edition published in ed. US Nuclear Regulatory Commission. Archived from the original on March 5, Retrieved January 16, The New York Times.

October 12, Archived from the original on March 6, June 27, Archived from the original on August 18, ANI News. Archived from the original on 24 February The Independent. UN News. Reprocessing refers to the chemical separation of fissionable uranium and plutonium from spent fuel. In the United States the regulatory regime has varied dramatically across administrations.

A systematic literature review from concludes that there is very limited information on economics and finance of MSRs, with low quality of the information and that cost estimations are uncertain. In the specific case of the stable salt reactor SSR where the radioactive fuel is contained as a molten salt within fuel pins and the primary circuit is not radioactive, operating costs are likely to be lower. While many design variants have been proposed, there are three main categories regarding the role of molten salt:.

The use of molten salt as fuel and as coolant are independent design choices – the original circulating-fuel-salt MSRE and the more recent static-fuel-salt SSR use salt as fuel and salt as coolant; the DFR uses salt as fuel but metal as coolant; and the FHR has solid fuel but salt as coolant.

MSRs can be burners or breeders. They can be fast or thermal or epithermal. Thermal reactors typically employ a moderator usually graphite to slow the neutrons down and moderate temperature. They can accept a variety of fuels low-enriched uranium, thorium, depleted uranium , waste products [22] and coolants fluoride, chloride, lithium, beryllium, mixed. Fuel cycle can be either closed or once-through. The reactor can adopt a loop, modular or integral configuration.

Variations include:. The molten salt fast reactor MSFR is a proposed design with the fuel dissolved in a fluoride salt coolant. They have been studied for almost a decade, mainly by calculations and determination of basic physical and chemical properties in the European Union and Russian Federation.

When steady state is achieved in a MSFR, there is no longer a need for uranium enrichment facilities. MSFRs may be breeder reactors. They operate without a moderator in the core such as graphite, so graphite life-span is no longer a problem. This results in a breeder reactor with a fast neutron spectrum that operates in the Thorium fuel cycle.

MSFRs contain relatively small initial inventories of U. MSFRs run on liquid fuel with no solid matter inside the core. This leads to the possibility of reaching specific power that is much higher than reactors using solid fuel. The heat produced goes directly into the heat transfer fluid. In the MSFR, a small amount of molten salt is set aside to be processed for fission product removal and then returned to the reactor. This gives MSFRs the capability of reprocessing the fuel without stopping the reactor.

This is very different compared to solid-fueled reactors because they have separate facilities to produce the solid fuel and process spent nuclear fuel. The MSFR can operate using a large variety of fuel compositions due to its on-line fuel control and flexible fuel processing. The core’s shape is a compact cylinder with a height to diameter ratio of 1 where liquid fluoride fuel salt flows from the bottom to the top.

The return circulation of the salt, from top to bottom, is broken up into 16 groups of pumps and heat exchangers located around the core. The fuel salt takes approximately 3 to 4 seconds to complete a full cycle.

During operation, the fuel salt circulation speed can be adjusted by controlling the power of the pumps in each sector. The intermediate fluid circulation speed can be adjusted by controlling the power of the intermediate circuit pumps. The temperature of the intermediate fluid in the intermediate exchangers can be managed through the use of a double bypass.

During controlled routine draining, fuel salt is transferred to actively cooled storage tanks. The fuel temperature can be lowered before draining, this may slow down the process. This type of draining could be done every 1 to 5 years when the sectors are replaced. Emergency draining is done when an irregularity occurs during operation. The fuel salt can be drained directly into the emergency draining tank either by active devices or by passive means.

The draining must be fast to limit the fuel salt heating in a loss of heat removal event. The fluoride salt-cooled high-temperature reactor FHR , also called advanced high temperature reactor AHTR , [27] is also a proposed Generation IV molten salt reactor variant regarded promising for the long-term future.

It uses liquid salt as a coolant in the primary loop, rather than a single helium loop. Early AHTR research focused on graphite in the form of graphite rods that would be inserted in hexagonal moderating graphite blocks, but current studies focus primarily on pebble-type fuel.

Reactors containing molten thorium salt, called liquid fluoride thorium reactors LFTR , would tap the thorium fuel cycle. Private companies from Japan, Russia, Australia and the United States, and the Chinese government, have expressed interest in developing this technology.

Advocates estimate that five hundred metric tons of thorium could supply U. Geological Survey estimates that the largest-known U. The stable salt reactor is a relatively recent concept which holds the molten salt fuel statically in traditional LWR fuel pins.

The fuel pins are immersed in a separate, non-fissionable fluoride salt which acts as primary coolant. A prototypical example of a dual fluid reactor is the lead-cooled, salt-fueled reactor.

The displacement of water in the lower 1. This “positive scram” effect was discovered in at the Ignalina Nuclear Power Plant. The narrow space between the rod and its channel hinders water flow around the rods during their movement and acts as a fluid damper, which is the primary cause of their slow insertion time nominally 18—21 seconds for the reactor control and protection system rods, or about 0.

The division of the control rods between manual and emergency protection groups was arbitrary; the rods could be reassigned from one system to another during reactor operation without technical or organizational problems. Additional static boron-based absorbers are inserted into the core when it is loaded with fresh fuel.

About absorbers are added during initial core loading. These absorbers are gradually removed with increasing burnup. The reactor’s void coefficient depends on the core content; it ranges from negative with all the initial absorbers to positive when they are all removed. The moisture and temperature of the outlet gas is monitored; an increase of them is an indicator of a coolant leak. The reactor has two independent cooling circuits, each having four main circulating pumps three operating, one standby that service one half of the reactor.

The resulting feedwater is led to the steam separators by feedwater pumps and mixed with water from them at their outlets. From the bottom of the steam separators, the feedwater is led by 12 downpipes from each separator to the suction headers of the main circulation pumps, and back into the reactor. The turbine consists of one high-pressure rotor cylinder and four low-pressure ones.

Five low-pressure separators-preheaters are used to heat steam with fresh steam before being fed to the next stage of the turbine. The uncondensed steam is fed into a condenser, mixed with condensate from the separators, fed by the first-stage condensate pump to a chemical ion-exchange purifier, then by a second-stage condensate pump to four deaerators where dissolved and entrained gases are removed; deaerators also serve as storage tanks for feedwater.

From the deaerators, the water is pumped through filters and into the bottom parts of the steam separator drums. Each pump has a flow control valve and a backflow preventing check valve on the outlet, and shutoff valves on both inlet and outlet. Each of the pressure channels in the core has its own flow control valve so that the temperature distribution in the reactor core can be optimized. Each channel has a ball type flow meter.

With few absorbers in the reactor core, such as during the Chernobyl accident, the positive void coefficient of the reactor makes the reactor very sensitive to the feedwater temperature. Bubbles of boiling water lead to increased power, which in turn increases the formation of bubbles.

If the coolant temperature is too close to its boiling point, cavitation can occur in the pumps and their operation can become erratic or even stop entirely. At low reactor power, therefore, the inlet temperature may become dangerously high. The water is kept below the saturation temperature to prevent film boiling and the associated drop in heat transfer rate. The reactor is tripped in cases of high or low water level in the steam separators with two selectable low-level thresholds ; high steam pressure; low feedwater flow; loss of two main coolant pumps on either side.

These trips can be manually disabled. The level of water in the steam separators, the percentage of steam in the reactor pressure tubes, the level at which the water begins to boil in the reactor core, the neutron flux and power distribution in the reactor, and the feedwater flow through the core have to be carefully controlled. The level of water in the steam separator is mainly controlled by the feedwater supply, with the deaerator tanks serving as a water reservoir.

The reactor is equipped with an emergency core cooling system ECCS , consisting of dedicated water reserve tank, hydraulic accumulators, and pumps. ECCS piping is integrated with the normal reactor cooling system. The ECCS has three systems, connected to the coolant system headers. In case of damage, the first ECCS subsystem provides cooling for up to seconds to the damaged half of the coolant circuit the other half is cooled by the main circulation pumps , and the other two subsystems then handle long-term cooling of the reactor.

The short-term ECCS subsystem consists of two groups of six accumulator tanks, containing water blanketed with nitrogen under pressure of 10 megapascals 1, psi , connected by fast-acting valves to the reactor.

The third group is a set of electrical pumps drawing water from the deaerators. The short-term pumps can be powered by the spindown of the main turbogenerators. ECCS for long-term cooling of the damaged circuit consists of three pairs of electrical pumps, drawing water from the pressure suppression pools; the water is cooled by the plant service water by means of heat exchangers in the suction lines.

Each pair is able to supply half of the maximum coolant flow. ECCS for long-term cooling of the intact circuit consists of three separate pumps drawing water from the condensate storage tanks, each able to supply half of the maximum flow. Some valves that require uninterrupted power are also backed up by batteries. The distribution of power density in the reactor is measured by ionization chambers located inside and outside the core. The physical power density distribution control system PPDDCS has sensors inside the core; the reactor control and protection system RCPS uses sensors in the core and in the lateral biological shield tank.

The external sensors in the tank are located around the reactor middle plane, therefore do not indicate axial power distribution nor information about the power in the central part of the core.

There are over radial and 12 axial power distribution monitors, employing self-powered detectors. Reactivity meters and removable startup chambers are used for monitoring of reactor startup.

Total reactor power is recorded as the sum of the currents of the lateral ionization chambers. The moisture and temperature of the gas circulating in the channels is monitored by the pressure tube integrity monitoring system.

The RCPS system consists of movable control rods. Both systems, however, have deficiencies, most noticeably at low reactor power levels. Below those levels, the automatic systems are disabled and the in-core sensors are not accessible. Without the automatic systems and relying only on the lateral ionization chambers, control of the reactor becomes very difficult; the operators do not have sufficient data to control the reactor reliably and have to rely on their intuition. During startup of a reactor with a poison-free core this lack of information can be manageable because the reactor behaves predictably, but a non-uniformly poisoned core can cause large nonhomogenities of power distribution, with potentially catastrophic results.

The reactor emergency protection system EPS was designed to shut down the reactor when its operational parameters are exceeded. However, the slow insertion speed of the control rods, together with their design causing localized positive reactivity as the displacer moves through the lower part of the core, created a number of possible situations where initiation of the EPS could itself cause or aggravate a reactor runaway. Its purpose was to assist the operator with steady-state control of the reactor.

The operators could disable some safety systems, reset or suppress some alarm signals, and bypass automatic scram , by attaching patch cables to accessible terminals. This practice was allowed under some circumstances. The reactor is equipped with a fuel rod leak detector. A scintillation counter detector, sensitive to energies of short-lived fission products, is mounted on a special dolly and moved over the outlets of the fuel channels, issuing an alert if increased radioactivity is detected in the steam-water flow.

In RBMK control rooms there are two large panels or mimic displays representing a top view of the reactor. Also a harder neutron spectrum helps to achieve acceptable breeding without protactinium isolation. If Pa separation is specified, this must be done quite often for example, every 10 days to be effective. This is only feasible if the costs are much lower than current costs for reprocessing solid fuel. Newer designs usually avoid the Pa removal [1] and send less salt to reprocessing, which reduces the required size and costs for the chemical separation.

It also avoids proliferation concerns due to high purity U that might be available from the decay of the chemical separated Pa. Separation is more difficult if the fission products are mixed with thorium, because thorium, plutonium and the lanthanides rare earth elements are chemically similar.

One process suggested for both separation of protactinium and the removal of the lanthanides is the contact with molten bismuth. In a redox -reaction some metals can be transferred to the bismuth melt in exchange for lithium added to the bismuth melt. At low lithium concentrations U, Pu and Pa move to the bismuth melt. At more reducing conditions more lithium in the bismuth melt the lanthanides and thorium transfer to the bismuth melt too.

The fission products are then removed from the bismuth alloy in a separate step, e. A similar method may also be possible with other liquid metals like aluminum. Thorium-fueled molten salt reactors offer many potential advantages compared to conventional solid uranium fueled light water reactors: [8] [20] [38] [39] [40] [41].

LFTRs are quite unlike today’s operating commercial power reactors. These differences create design difficulties and trade-offs:. It was being developed by a consortium including members from Japan, the United States, and Russia.

As a breeder reactor, it converts thorium into nuclear fuels. The People’s Republic of China has initiated a research and development project in thorium molten-salt reactor technology. Its ultimate target is to investigate and develop a thorium based molten salt nuclear system in about 20 years. This would be followed by a 10 MW demonstrator reactor and a MW pilot reactors. An expansion of staffing has increased to as of China plans to follow up the experiment with a MW version by Kirk Sorensen, former NASA scientist and Chief Nuclear Technologist at Teledyne Brown Engineering , has been a long-time promoter of thorium fuel cycle and particularly liquid fluoride thorium reactors.

In , Sorensen founded Flibe Energy, a company that initially intends to develop 20—50 MW LFTR small modular reactor designs to power military bases; Sorensen noted that it is easier to promote novel military designs than civilian power station designs in the context of the modern US nuclear regulatory and political environment.

As of June , TEG had ceased operations. It was formally launched at the House of Lords on 8 September Weinberg , who pioneered the thorium molten salt reactor research. Thorcon is a proposed molten salt converter reactor by Martingale, Florida. It features a simplified design with no reprocessing and swappable cans for ease of equipment replacement, in lieu of higher nuclear breeding efficiency.

On 5 September , The Dutch Nuclear Research and Consultancy Group announced that research on the irradiation of molten thorium fluoride salts inside the Petten high-flux reactor was underway. From Wikipedia, the free encyclopedia. Type of nuclear reactor that uses molten material as fuel. See also: Thorium-based nuclear power. Main article: Breeder reactor. Main article: Rankine cycle. Main article: Brayton cycle. This section may be too technical for most readers to understand.

Please help improve it to make it understandable to non-experts , without removing the technical details. April Learn how and when to remove this template message. Nuclear Engineering and Design. San Francisco, CA. Huffington Post. ZME Science. Retrieved 12 August Discover Magazine. Retrieved 22 January Pittsburgh Press. Retrieved 18 October The Tuscaloosa News.

American Scientist. Archived from the original PDF on 8 December Nature Geoscience. Bibcode : NatGe

На каждой руке всего по три пальца, скрюченных, искривленных. Но Беккера интересовало отнюдь не это уродство. – Боже ты мой, – пробормотал лейтенант из другого конца комнаты. – Он японец, а не китаец. Беккер поднял .

Retrieved 28 August World Nuclear News. Retrieved 17 June Retrieved 2 February Teollisuuden Voima. January Retrieved 16 April International Nuclear Safety Center. Archived from the original on 3 December Retrieved 13 March Nuclear Engineering International. Archived from the original on 4 September Retrieved 12 January Retrieved 7 January Retrieved 20 September Retrieved 2 July Retrieved 24 July Retrieved 10 August Retrieved 15 April Worldwatch Institute.

Archived from the original on 27 September Helsingin Sanomat. Archived from the original on 20 October Power Reactor Information System. Archived from the original on 19 September Nuclear Street. Retrieved 9 December Retrieved 16 December Retrieved 29 January Archived from the original on 26 February Financial Times. Archived from the original on 1 February Retrieved 18 January Retrieved 27 February Archived from the original on 4 March Retrieved 28 February Retrieved 17 July Power Engineering.

Retrieved 23 November Retrieved 29 November Retrieved 13 December The Wall Street Journal. Retrieved 4 December Retrieved 12 March Retrieved 4 June Retrieved 7 March Physicians for Social Responsibility. Archived from the original on 28 July Archived from the original on 13 June Retrieved 21 February Archived from the original on 13 February Retrieved 14 December Radiation and Nuclear Safety Authority.

Retrieved 22 December Archived from the original on 18 January Ministry of Economic Affairs and Employment Finland. Retrieved 2 September Retrieved 24 January Berlin, Germany. Retrieved 1 November Munich, Germany. Retrieved 9 October Retrieved 11 February Retrieved 15 June Retrieved 25 February Ministry of Economic Affairs and Employment. Retrieved 18 June Yle Uutiset. Archived from the original on 26 March Retrieved 26 March Retrieved 23 August Categories : Nuclear power stations in Finland Radioactive waste repositories Nuclear power stations using boiling water reactors Nuclear power stations using pressurized water reactors Nuclear power stations with reactors under construction Nuclear power stations with proposed reactors Nuclear power stations using EPR reactors Eurajoki Buildings and structures in Satakunta.

TVO said that it is “preparing for the possibility” that the third unit at Olkiluoto may not start operating until [68]. Areva shutting down construction due to dispute over compensations and unfinished automation planning. Operation estimated to be delayed until — Areva announced it expected construction completion and commissioning to start in mid, with operation expected to start in TVO stated they were surprised that commissioning was expected to take so long.

As the fuel of a LFTR is a molten salt mixture, it is attractive to use pyroprocessing , high temperature methods working directly with the hot molten salt. Pyroprocessing does not use radiation sensitive solvents and is not easily disturbed by decay heat. It can be used on highly radioactive fuel directly from the reactor.

Ideally everything except new fuel thorium and waste fission products stays inside the plant. One potential advantage of a liquid fuel is that it not only facilitates separating fission-products from the fuel, but also isolating individual fission products from one another, which is lucrative for isotopes that are scarce and in high-demand for various industrial radiation sources for testing welds via radiography , agricultural sterilizing produce via irradiation , and medical uses Molybdenum which decays into Technetiumm , a valuable radiolabel dye for marking cancerous cells in medical scans.

The more noble metals Pd , Ru , Ag , Mo , Nb , Sb , Tc do not form fluorides in the normal salt, but instead fine colloidal metallic particles. They can plate out on metal surfaces like the heat exchanger, or preferably on high surface area filters which are easier to replace. Still, there is some uncertainty where they end up, as the MSRE only provided a relatively short operating experience and independent laboratory experiments are difficult.

Gases like Xe and Kr come out easily with a sparge of helium. In addition, some of the “noble” metals are removed as an aerosol. The quick removal of Xe is particularly important, as it is a very strong neutron poison and makes reactor control more difficult if unremoved; this also improves neutron economy.

The gas mainly He, Xe and Kr is held for about 2 days until almost all Xe and other short lived isotopes have decayed. Most of the gas can then be recycled. After an additional hold up of several months, radioactivity is low enough to separate the gas at low temperatures into helium for reuse , xenon for sale and krypton, which needs storage e.

For cleaning the salt mixture several methods of chemical separation were proposed. The pyroprocesses of the LFTR salt already starts with a suitable liquid form, so it may be less expensive than using solid oxide fuels. However, because no complete molten salt reprocessing plant has been built, all testing has been limited to the laboratory, and with only a few elements.

There is still more research and development needed to improve separation and make reprocessing more economically viable. Uranium and some other elements can be removed from the salt by a process called fluorine volatility: A sparge of fluorine removes volatile high- valence fluorides as a gas. This is mainly uranium hexafluoride , containing the uranium fuel, but also neptunium hexafluoride , technetium hexafluoride and selenium hexafluoride , as well as fluorides of some other fission products e.

The volatile fluorides can be further separated by adsorption and distillation. Handling uranium hexafluoride is well established in enrichment. The higher valence fluorides are quite corrosive at high temperatures and require more resistant materials than Hastelloy. At the MSRE reactor fluorine volatility was used to remove uranium from the fuel salt. Also for use with solid fuel elements fluorine volatility is quite well developed and tested. Another simple method, tested during the MSRE program, is high temperature vacuum distillation.

The lower boiling point fluorides like uranium tetrafluoride and the LiF and BeF carrier salt can be removed by distillation.

Under vacuum the temperature can be lower than the ambient pressure boiling point. The chemical separation for the 2-fluid designs, using uranium as a fissile fuel can work with these two relatively simple processes: [35] Uranium from the blanket salt can be removed by fluorine volatility, and transferred to the core salt.

To remove the fissile products from the core salt, first the uranium is removed via fluorine volatility. Then the carrier salt can be recovered by high temperature distillation.

The fluorides with a high boiling point, including the lanthanides stay behind as waste. The early Oak Ridge’s chemistry designs were not concerned with proliferation and aimed for fast breeding. They planned to separate and store protactinium , so it could decay to uranium without being destroyed by neutron capture in the reactor.

The protactinium removal step is not required per se for a LFTR. Alternate solutions are operating at a lower power density and thus a larger fissile inventory for 1 or 1.

Also a harder neutron spectrum helps to achieve acceptable breeding without protactinium isolation. If Pa separation is specified, this must be done quite often for example, every 10 days to be effective.

This is only feasible if the costs are much lower than current costs for reprocessing solid fuel. Newer designs usually avoid the Pa removal [1] and send less salt to reprocessing, which reduces the required size and costs for the chemical separation. It also avoids proliferation concerns due to high purity U that might be available from the decay of the chemical separated Pa.

Separation is more difficult if the fission products are mixed with thorium, because thorium, plutonium and the lanthanides rare earth elements are chemically similar. One process suggested for both separation of protactinium and the removal of the lanthanides is the contact with molten bismuth.

In a redox -reaction some metals can be transferred to the bismuth melt in exchange for lithium added to the bismuth melt. At low lithium concentrations U, Pu and Pa move to the bismuth melt. At more reducing conditions more lithium in the bismuth melt the lanthanides and thorium transfer to the bismuth melt too. The fission products are then removed from the bismuth alloy in a separate step, e.

A similar method may also be possible with other liquid metals like aluminum. Thorium-fueled molten salt reactors offer many potential advantages compared to conventional solid uranium fueled light water reactors: [8] [20] [38] [39] [40] [41].

An expansion of staffing has increased to as of China plans to follow up the experiment with a MW version by Kirk Sorensen, former NASA scientist and Chief Nuclear Technologist at Teledyne Brown Engineering , has been a long-time promoter of thorium fuel cycle and particularly liquid fluoride thorium reactors.

He first researched thorium reactors while working at NASA, while evaluating power plant designs suitable for lunar colonies. Material about this fuel cycle was surprisingly hard to find, so in Sorensen started “energyfromthorium. In , Sorensen coined the liquid fluoride thorium reactor and LFTR nomenclature to describe a subset of molten salt reactor designs based on liquid fluoride-salt fuels with breeding of thorium into uranium in the thermal spectrum. In , Sorensen founded Flibe Energy, a company that initially intends to develop 20—50 MW LFTR small modular reactor designs to power military bases; Sorensen noted that it is easier to promote novel military designs than civilian power station designs in the context of the modern US nuclear regulatory and political environment.

Thorium Energy Generation Pty. Limited TEG was an Australian research and development company dedicated to the worldwide commercial development of LFTR reactors, as well as thorium accelerator-driven systems. As of June , TEG had ceased operations. It was formally launched at the House of Lords on 8 September Weinberg , who pioneered the thorium molten salt reactor research.

Thorcon is a proposed molten salt converter reactor by Martingale, Florida. It features a simplified design with no reprocessing and swappable cans for ease of equipment replacement, in lieu of higher nuclear breeding efficiency. On 5 September , The Dutch Nuclear Research and Consultancy Group announced that research on the irradiation of molten thorium fluoride salts inside the Petten high-flux reactor was underway.

From Wikipedia, the free encyclopedia. Type of nuclear reactor that uses molten material as fuel. See also: Thorium-based nuclear power. Main article: Breeder reactor. Main article: Rankine cycle.

Main article: Brayton cycle. This section may be too technical for most readers to understand. Please help improve it to make it understandable to non-experts , without removing the technical details. April Learn how and when to remove this template message. Nuclear Engineering and Design. San Francisco, CA.

Huffington Post. ZME Science. Retrieved 12 August Discover Magazine. Retrieved 22 January Pittsburgh Press. Retrieved 18 October The Tuscaloosa News. American Scientist. Archived from the original PDF on 8 December Nature Geoscience. Bibcode : NatGe Argonne’s Nuclear Science and Technology Legacy. Argonne National Laboratory. Mountain View, CA. Archived from the original PDF on 12 December Oak Ridge National Laboratory.

Archived from the original PDF on 29 October Retrieved 7 April S2CID Archived from the original PDF on 22 January Archived from the original PDF on 15 May Bibcode : EnST PMID Progress in Nuclear Energy. Archived from the original PDF on 19 January Archived from the original PDF on 26 September Archived from the original PDF on 21 October Conceptual design characteristics of a denatured molten-salt reactor with once-through fueling PDF.

The basic design of pebble-bed reactors features spherical fuel elements called pebbles. These tennis ball-sized pebbles (approx. cm or in in diameter) are made of pyrolytic graphite (which acts as the moderator), and they contain thousands of micro-fuel particles called TRISO particles. These TRISO fuel particles consist of a fissile material (such as U) surrounded . Moving bed biofilm reactor (MBBR) is a type of wastewater treatment process that was first invented by Prof. Hallvard Ødegaard at Norwegian University of Science and Technology in the late s. It was commercialized by Kaldnes Miljöteknologi (now called AnoxKaldnes and owned by Veolia Water Technologies).There are over wastewater treatment systems (both . The B Reactor at the Hanford Site, near Richland, Washington, was the first large-scale nuclear reactor ever built. The project was a key part of the Manhattan Project, the United States nuclear weapons development program during World War replace.me purpose was to convert natural (not isotopicly enriched) uranium metal into plutonium by neutron activation, as plutonium is .

The name refers to its design where, instead of a large steel pressure vessel surrounding the entire core, the core is surrounded by a cylindrical annular steel tank inside a concrete vault and each fuel assembly is enclosed in an individual 8 cm inner diameter pipe called a “technological channel”. The channels also contain the coolant, and are surrounded by graphite. Certain aspects of the original RBMK reactor design, such as the large positive void coefficient , the ‘positive scram effect’ of the control rods [3] and instability at low power levels, contributed to the Chernobyl disaster , in which an RBMK experienced an uncontrolled nuclear chain reaction , leading to a steam and hydrogen explosion, large fire, and subsequent core meltdown.

Radioactivity was released over a large portion of Europe. The disaster prompted worldwide calls for the reactors to be completely decommissioned; however, there is still considerable reliance on RBMK facilities for power in Russia. Most of the flaws in the design of RBMK reactors were corrected after the Chernobyl accident and a dozen reactors have since been operating without any serious incidents for over thirty years.

The RBMK was the culmination of the Soviet nuclear power program to produce a water-cooled power reactor with dual-use potential based on their graphite-moderated plutonium production military reactors. By using a minimalist design that used regular light water for cooling and graphite for moderation , it was possible to use fuel with a lower enrichment 1.

This allowed for an extraordinarily large and powerful reactor that could be built rapidly, largely out of parts fabricated on-site instead of by specialized factories. The initial MWe design also left room for development into yet more powerful reactors.

For comparison, the EPR has a net electric nameplate capacity of MW MW thermal and is among the most powerful reactor types ever built. The RBMK’s design was finalized in At that time it was the world’s largest nuclear reactor design, surpassing western designs and the VVER an earlier Soviet PWR reactor design in power output and physical size, being 20 times larger by volume than contemporary western reactors. Similarly to CANDU reactors it could be produced without the specialized industry required by the large and thick-walled reactor pressure vessels such as those used by VVER reactors, thus increasing the number of factories capable of manufacturing RBMK reactor components.

No prototypes of the RBMK were built; it was put directly into mass production. The RBMK was proclaimed by some as the national reactor of the Soviet Union, probably due to nationalism because of its unique design, large size and power output and especially since the VVER was called the American reactor by its detractors in the Soviet Union, since its design is more similar to that of western PWR reactors. A top-secret invention patent for the RBMK design was filed by Anatoly Aleksandrov from the Kurchatov Institute of Atomic Energy, who personally took credit for the design of the reactor, with the Soviet patent office.

Because a containment building would have needed to be very large and thus expensive doubling the cost of each unit due to the large size of the RBMK, it was originally omitted from the design. It was argued by its designers that the RBMK’s strategy of having each fuel assembly in its own channel with flowing cooling water was an acceptable alternative for containment.

The RBMK was favored over the VVER by the Soviet Union due to its ease of manufacture due to a lack of a large and thick-walled reactor pressure vessel and relatively complex associated steam generators and its large power output which would allow the Soviet government to easily meet their central economic planning targets.

This prompted a sudden overhaul of the RBMK. Plutonium production in an RBMK would have been achieved by operating the reactor under special thermal parameters, but this capability was abandoned early on. The redesign did not solve flaws that were not discovered until years later. Leningrad unit 1 opened in At Leningrad it was discovered that the RBMK, due to its high positive void coefficient, became harder to control as the uranium fuel was consumed or burned up, becoming unpredictable by the time it was shut down after three years for maintenance.

This made controlling the RBMK a very laborious, mentally and physically demanding task requiring the timely adjustment of dozens of parameters every minute, around the clock, constantly wearing out switches such as those used for the control rods and causing operators to sweat. The enrichment percentage was thus increased to 2. Aleksandrov and Dollezhal did not investigate further or even deeply understand the problems in the RBMK, and the void coefficient was not analyzed in the manuals for the reactor.

Engineers at Chernobyl unit 1 had to create solutions to many of the RBMK’s flaws such as a lack of protection against no feedwater supply. Leningrad and Chernobyl units 1 both had partial meltdowns that were treated alongside other nuclear accidents at power plants as state secrets and so were unknown even to other workers at those same plants.

Instead, manuals were revised, which was believed to be enough to ensure safe operation as long as they were followed closely. However, the manuals were vague and Soviet power plant staff already had a habit of bending the rules in order to meet economic targets, despite inadequate or malfunctioning equipment.

Crucially, it was not made clear that a number of control rods had to stay in the reactor at all times in order to protect against an accident, as loosely articulated by the Operational Reactivity Margin ORM parameter. A year lifetime is envisaged for many of the units, after mid-life refurbishment. The reactor pit or vault is made of reinforced concrete and has dimensions It houses the vessel of the reactor, which is annular, made of an inner and outer cylindrical wall and top and bottom metal plates that cover the space between the inner and outer walls, without covering the space surrounded by the vessel.

The reactor vessel is an annular steel cylinder with hollow walls and pressurized with nitrogen gas, with an inner diameter and height of In order to absorb axial thermal expansion loads, it is equipped with two bellows compensators , one on the top and another on the bottom, in the spaces between the inner and outer walls.

The vessel surrounds the graphite core block stack, which serves as moderator. The graphite stack is kept in a helium-nitrogen mixture for providing an inert atmosphere for the graphite, preventing it from potential fires and for excess heat transfer from the graphite to the coolant channels. There are holes of The reactor has an active core region There are tons of graphite blocks in an RBMK reactor.

The reactor vessel has on its outer side an integral cylindrical annular water tank, [12] a welded structure with 3cm thick walls, an inner diameter of The water is supplied to the compartments from the bottom and removed from the top; the water can be used for emergency reactor cooling. The tank contains thermocouples for sensing the water temperature and ion chambers for monitoring the reactor power.

The UBS is a cylindrical disc of 3m x 17m in size and tons in weight. The top and bottom are covered with 4cm thick steel plates, welded to be helium-tight, and additionally joined by structural supports. The space between the plates and pipes is filled with serpentinite , [8] a rock containing significant amounts of bound water.

The serpentinite provides the radiation shielding of the biological shield and was applied as a special concrete mixture. The disk is supported on 16 rollers, located on the upper side of the reinforced cylindrical water tank. The structure of the UBS supports the fuel and control channels, the floor above the reactor in the central hall, and the steam-water pipes. It is penetrated by the tubes for the lower ends of the pressure channels and carries the weight of the graphite stack and the coolant inlet piping.

A steel structure, two heavy plates intersecting in right angle under the center of the LBS and welded to the LBS, supports the LBS and transfers the mechanical load to the building. Above that is Assembly 11, made up of the upper shield cover or channel covers. Their top surfaces form part of the floor of the reactor hall and serve as part of the biological shield and for thermal insulation of the reactor space.

They consist of serpentinite concrete blocks that cover individual removable steel-graphite plugs, located over the tops of the channels, forming what resembles a circle with a grid pattern. The fuel channels consist of welded zircaloy pressure tubes 8cm in inner diameter with 4mm thick walls, led through the channels in the center of the graphite moderator blocks. The top and bottom parts of the tubes are made of stainless steel , and joined with the central zircaloy segment with zirconium-steel alloy couplings.

The pressure tube is held in the graphite stack channels with two alternating types of 20mm high split graphite rings; one is in direct contact with the tube and has 1. The pressure tubes are welded to the top and bottom plates of the reactor vessel. While most of the heat energy from the fission process is generated in the fuel rods, approximately 5. This energy must be removed to avoid overheating the graphite.

The rest of the graphite heat is removed from the control rod channels by forced gas circulation through the gas circuit.

There are fuel channels and control rod channels in the first generation RBMK reactor cores. The seal plug has a simple design, to facilitate its removal and installation by the remotely controlled online refueling machine. The fuel channels may, instead of fuel, contain fixed neutron absorbers, or be filled completely with cooling water. They may also contain silicon-filled tubes in place of a fuel assembly, for the purpose of doping for semiconductors.

These channels could be identified by their corresponding servo readers, which would be blocked and replaced with the atomic symbol for silicon. The small clearance between the pressure channel and the graphite block makes the graphite core susceptible to damage.

If a pressure channel deforms, e. The fuel pellets are made of uranium dioxide powder, sintered with a suitable binder into pellets The material may contain added europium oxide as a burnable nuclear poison to lower the reactivity differences between a new and partially spent fuel assembly. A 2mm hole through the axis of the pellet serves to reduce the temperature in the center of the pellet and facilitates removal of gaseous fission products.

The rods are filled with helium at 0. Retaining rings help to seat the pellets in the center of the tube and facilitate heat transfer from the pellet to the tube. The pellets are axially held in place by a spring.

Each rod contains 3. The fuel rods are 3. The fuel assemblies consist of two sets “sub-assemblies” with 18 fuel rods and 1 carrier rod.

The fuel rods are arranged along the central carrier rod, which has an outer diameter of 1. All rods of a fuel assembly are held in place with 10 stainless steel spacers separated by mm distance.

The spent rod is then placed in a cooling pond. The capacity of the refueling machine with the reactor at nominal power level is two fuel assemblies per day, with peak capacity of five per day. The total amount of fuel under stationary conditions is tons. Most of the reactor control rods are inserted from above; 24 shortened rods are inserted from below and are used to augment the axial power distribution control of the core.

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