The first Magnox plant had been run for plutonium production, so it had characteristics that were not the most economical for electricity generation. It has been tested by Ukrainian researchers and was proposed to convert the boiling water reactors at the Fukushima Daiichi nuclear disaster into liquid tin cooled reactors.[8]. A gas cooled reactor (in short, GCR) is a nuclear reactor that works with graphite as a neutron moderator and a gas including carbon dioxide or helium in available designs as coolant. '5Mhl8ljM%RVQ r qvpS)\GCnbM68&9q>#2q[a)P2t:9{ X4`jl6>!ZS]w.yT**sbF"Xh#={%_:0/ M\@. The second nuclear submarine, USSSeawolf was the only U.S. submarine to have a sodium-cooled, beryllium-moderated nuclear power plant. A shutdown system operating by injecting boron beads into the reactor is applied if the reactor has to be depressurized with inadequate control rods reduced. In the United States, which does not reprocess, storage pools have continued to receive spent fuel, and some of the pools are filling up. Each type of SMR has its own advantages and disadvantages, and the choice of reactor technology depends on various factors, including the intended use, the site characteristics, and the regulatory requirements. It was commissioned in 1957, but it had leaks in its superheaters, which were bypassed. University, Winter 2018. However, the reactor core must be larger in size for the same output. increase. A reactor of this kind consists of a tank, or calandria vessel, containing a cold heavy water moderator at atmospheric pressure. Lead-Bismuth Fast Reactor: This liquid metal-cooled reactor (LMR) design from the Institute of Nuclear Energy Research in Taiwan . Liquid sodium is currently used in the Russian BN-600 and BN-800 reactorsthe only ones operating SFRs so far in the worldand is proposed to be used in Generation IV SFRs. To improve cooling with water, most reactor designs are highly pressurized to raise the boiling point, which presents safety and maintenance issues that liquid metal designs lack. The high-temperature gas-cooled reactor (HTGR), as mentioned above in Fuel types, is fueled by a mixture of graphite and fuel-bearing microspheres. Furthermore, because the BWRs power density is somewhat lower than that of the PWR, the pressure vessel must be built to a larger diameter for the same reactor power. other rights, including commercial rights, are reserved to the weapons proliferation, The GIF's first action was to select six promising This makes it difficult to use water as a coolant for a fast reactor because the water tends to slow (moderate) the fast neutrons into thermal neutrons (although concepts for reduced moderation water reactors exist). Each fuel assembly to be removed is grasped by a fuel-handling tool and then lifted from its position in the core into a shielded cask, within which the assembly is transferred to a storage pool for cooling while it is still highly radioactive. The Magnox design is replaced by the advanced gas cooled reactor with a similar cooling system but some changes to improve the economic performance. The characteristics and design features of these reactors differ significantly from those of LWRs, stemming from the properties of fast neutrons and the chemical nature of liquid sodium. Sodium and NaK do, however, ignite spontaneously on contact with air and react violently with water, producing hydrogen gas. Some gas cooled reactors have been constructed and operated using either carbon dioxide gas or helium for the reactor core cooling. Further advantages of tin are the high boiling point and the ability to build a crust even over liquid tin helps to cover poisonous leaks and keeps the coolant in and at the reactor. The exploded Chernobyls No.4 reactor was a second-generation reactor. 0000010115 00000 n The reactor is designed to produce a maximum thermal power of 3 Mw and a maximum exit He temperature of 2400 deg F. The purpose of the experimert is to evaluate the advantages of the simple fuel against the disadvantages of the associated operation of a contaminated coolant loop. This book consolidates the latest research to provide readers with a clear understanding of the advantages and disadvantages of the thermal, membrane, and hybrid desalination processes, along with a comprehensive methodology to guide the reader on how to perform levelized cost analyses for water and electricity. One of the methods of converting biomass into valuable products is the process of pyrolysis. 2. [7] B. Fleming, Water is a much stronger neutron moderator because the hydrogen atoms found in water are much lighter than metal atoms, and therefore neutrons lose more energy in collisions with hydrogen atoms. Thanks to its unique advantages of high power-to-mass ratio, shallow reactivity poisoning and quick response to reactivity control , a liquid metal-cooled space nuclear reactor, which adopts a fast neutron spectrum reactor core cooled by liquid metal or liquid metal alloys, is the preferred solution to provide the necessary high-power supply . However, in the second generation of the gas cooled reactors, the steam generators are installed inside the concrete pressure vessel, which needs a much larger structure and, therefore, more capital costs. The use of liquid metal has many advantages because the reactor need not to be kept under pressure and they allow high power density than the conventional coolant. IRSN 2012/158, September 2012. 0000001604 00000 n The hot helium can be used directly as the working fluid in a high-temperature gas turbine, or its heat can be utilized to generate steam for a water cycle. There are two competitive designs of this reactor type: (1) a German pebble bed system that uses spherical fuel elements, nominally 60 mm (2.5 inches) in diameter, containing a graphite-and-fuel mixture coated in a graphite shell; and (2) an American version in which the fuel is loaded into precisely located graphite hexagonal prisms that interlock to create the core of the vessel. Liquid metallic sodium may be used to carry heat from the core. [10] The reactor was repaired and returned to service in September 1960 and ended operation in 1964. The AGR was the developed form of the Magnox reactor, the first-generation reactor design in the UK. A disadvantage of sodium is its chemical reactivity, which requires special precautions to prevent and suppress fires. In parallel to the British Magnox design, the UNGG reactor was developed independently to meet similar requirements for electric power and plutonium generation simultaneously. The initials SFR in particular refer to two Generation IV reactor proposals, one based on existing liquid metal cooled reactor (LMFR) technology using mixed oxide fuel (MOX), and one based on the metal-fueled integral fast reactor. project by the French Alternative Energies and Atomic Energy Commission 0000007220 00000 n (SCWR). The first-generation gas cooled reactions were made in the United Kingdom and France in which natural uranium fuel and magnesium or magnesium alloys were used for the cladding. The AGR was designed so that the final conditions of steam at the boiler stop valve were equal to that of conventional coal-fired power plants. This feature has given the CANDU higher capacity factors than other reactor types. If the temperature of the core increases, the core will expand slightly, which means that more neutrons will escape the core, slowing down the reaction. The most promising type of breeder reactor is the Liquid Metal Fast Breeder Reactor (LMFBR), which operates by using liquid sodium as its coolant, and breeds plutonium from uranium-238. Advantages and Disadvantages Advantages FBRs have improved neutron economy FBRs can recycle nuclear waste FBRs can produce fuel for thermal reactors FBRs liquid metals have superior heat transfer properties FBRs do not use pressure vessel Disadvantages FBRs must use superior control system Do You Know Which African American Inventor Created Which Product? IV Nuclear Reactors," Physics 241, Stanford University, Winter The heat exchanger is placed outside the concrete radiation shielding. [4,5]. Despite sodium's low specific heat (as compared to water), this enables the absorption of significant heat in the liquid phase, while maintaining large safety margins. It was available at the time of their development in the 1950s only in the United States or the Soviet Union. [5] G. De Clercq, It then flows to the heat exchangers located outside of the pressure vessel of the reactor concrete. Required fields are marked *. Hence, the salt can be both the fuel and the coolant at the same time. And fire hazard risk, corrosion and production of radioactive products are other threats. They were made the same as those of a coal-fired power plant, providing the same design of applied turbines and generation facilities. There are two proposals for a sodium cooled Gen IV LMFR, one based on oxide fuel, the other on the metal-fueled integral fast reactor. In the loop type, the heat exchangers are outside the reactor tank. Water passing through the core is allowed to boil at an intermediate pressure level. This value is better than modern Pressurized Water Reactors (PWRs), with a typical thermal efficiency of about 34%. The AGR design kept the graphite moderator and carbon dioxide coolant of the Magnox. primary sodium coolant does not directly exchange its heat with the It is focused on the following subjects: state of the art of liquid metal fast reactor (LMFR) development; design features and operating experience of demonstration and commercial sized nuclear power plants with sodium cooled fast reactors; lead-bismuth cooled (LBC) ship reactor operation experience and LBC fast power reactor development; In fact, the steam generators of a PWRthere are typically four of them in a big plantare larger than the reactor vessel itself. This figure demonstrates an early design of Magnox with a cylindrical steel pressure vessel. Given the A liquid metal cooled reactor (LMCR) is an advanced type of nuclear reactor that uses a liquid metal as the primary coolant. But, many second-generation reactors live up to 50 or 60 years. Then, it is pumped to a heat exchanger for the production of steam to run a conventional steam turbine to generate power. The many Member States are interested in working on advanced High-Temperature Gas Cooled Reactors (HTGRs) that employ helium as a coolant. It was succeeded at the same site by PFR, the Prototype Fast Reactor, which operated from 1974 to 1994 and used liquid sodium as its coolant. The sodium-cooled fast reactor (SFR) uses liquid metal (sodium) as a coolant instead of water that is typically used in U.S. commercial power plants. [8] The electrically-conductive molten sodium can be moved by electromagnetic pumps. These are of the gas-to-water heat exchanger types that use the once-through fundamental to boil the flowing water. Much larger size and weight of reactor per unit power. Abstract Iron-chromium-aluminum alloys containing 15-20 wt.% Cr and 4-6 wt.% Al have shown excellent corrosion resistance in the temperature range up to 600 C or higher in liquid lead and lead-bismuth eutectic environments by the formation of protective Al2O3 layers. Since both claddings react with water, they may be stored in a spent fuel pool only shortly. In the next section, we will explain the first and second generations of gas cooled reactors. "The "Aging However, the higher Cr and Al concentrations in ferritic alloys could be problematic because of severe embrittlement . Magnesium oxide has an order of magnitude lower probability of interacting with neutrons (thermal and fast) than elements such as iron. Many Generation IV reactors studied are liquid metal cooled: Bunker, Merle E. "Early Reactors From Fermis Water Boiler to Novel Power Prototypes" a chapter in, liquid metal fast breeder reactors (LMFBRs), http://library.lanl.gov/cgi-bin/getfile?00416628.pdf, "Neutron Scattering Lengths and cross sections", Atmospheric corrosion of tin and tin alloy, Ukraine advises Japan to use tin to cool Fukushima reactor, "40 Curious Nuclear Energy Facts You Should Know", https://en.wikipedia.org/w/index.php?title=Liquid_metal_cooled_reactor&oldid=1134133261, This page was last edited on 17 January 2023, at 04:17. The CO2 coolant circulates in the core, which reaches a temperature of 640 C and a pressure of about 40 bar. Following plants used low-enriched uraniumoxide fuel with stainless steel cladding. More recent designssmall modular reactors that produce 300 megawatts or lessmay be able to provide energy on a more economic scale and thus appeal to a much broader market. This change led to a greater burnup of 18,000 MW-days per fuel tonne, requiring less regular refueling. Sodium-Graphite Reactor (SGR) is a typical liquid metal cooled reactor that uses sodium as coolant and graphite as moderator. Fermi 1 in Monroe County, Michigan was an experimental, liquid sodium-cooled fast breeder reactor that operated from 1963 to 1972. The first reactor of this type was Calder Hall in 1956, which was often considered as the first commercial-scale electricity-producing reactor worldwide. A few examples include organic liquid-cooled and liquid-moderated reactors that can operate like a pressurized-water reactor but without requiring pressures in the primary circuit to be as high as those in the traditional PWR; sodium-cooled graphite-moderated reactors; and heavy-water reactors built in a pressure-vessel design. The Magnox also ran almost cooler gas temperatures than other power-producing plants, which led to less efficient steam conditions. In July 1959, the Sodium Reactor Experiment suffered a serious incident involving the partial melting of 13 of 43 fuel elements and a significant release of radioactive gases. Feed water from the condenser enters the boiler, the heated sodium potassium liquid passing through the tube gives heat to the water thus converting it into steam (superheated). The developmental work of the previous decades, however, resulted in the construction of a number of LMRs around the worldin the United States, Russia, France, Britain, Japan, and Germany. This Sodium exhibits the best combination of . This means that the inventory of transuranic waste is non existent from fast reactors. The advanced gas-cooled reactor (AGR) was developed in the United Kingdom as the successor to reactors of the Calder Hall class, which combined plutonium production and power generation. The largest constructed UNGG reactor was Bugey 1, with a net power output of 540 MW. These are opposed to the first generation reactors, which refer to the early class of power reactors. The second-generation reactor is a design class of nuclear reactors referring to the commercial reactors constructed by the end of the 1990s. [3] reactors, and therefore the coolant must have very good heat transfer properties. Experimental prototypes of both the American and German designs were built and operated from the 1960s to the 1980s, but by the early 1990s, they had resulted in no orders for commercial plants. suffered from corrosion and sodium leaks that resulted in runaway Like other reactors running to produce plutonium, conserving neutrons is a significant element of the design. 0000013241 00000 n Most LMRs are breeders or are capable of breeding, which is to say that they all produce more fissile material than they consume. The fuel assembly of a CANDU reactor, which consists of a bundle of short zirconium alloy-clad tubes containing natural uranium dioxide pellets, can be changed while the system is running. xref 0000001054 00000 n Each LWR design has its own advantages and disadvantages, and as a result, a competitive economic market has existed between the BWR and PWR concepts since the 1960s. The high temperature of the liquid metal is used to produce vapour at higher temperature leading to higher plant efficiency. Liquid metal coolant has been applied to both thermal- and fast-neutron reactors. A Russian breeder reactor, the BN-600, reported 27 sodium leaks in a 17-year period, 14 of which led to sodium fires.[9]. The arrangement of a sodium graphite reactor (SGR) is shown in Fig. Liquid metal cooled reactors were studied by Pratt & Whitney for use in nuclear aircraft as part of the Aircraft Nuclear Propulsion program.[9]. Fuel-to-cladding chemical interaction (FCCI) has to be accommodated. [3,4] Because of this, SFRs Ultimately, this fuel will be transferred to the U.S. Department of Energy for reprocessing or waste disposal or both, though a viable disposal program has not yet been established. The use of liquid metal has many advantages because the reactor need not to be kept under pressure and they allow high power density than the conventional coolant. The water in the secondary loop enters the steam generator at a pressure and temperature slightly below that required to initiate boiling. During the early stages of design, it was necessary to turn the beryllium cladding into stainless steel. In most LWRs a typical refueling cycle removes approximately one-third of the fuel assemblies. The core is in a metal-filled module sitting in a large pool of secondary . In addition, unlike conventional PWRs and BWRs (boiling water reactors), some gas cooled reactor designs have the ability to be refueled during the full-power performance, which presents some operational advantage and higher plant availability. 0000002574 00000 n The superheated water vapour is then used as the working fluid to turn the steam turbine. Of the ten units, all ended by the end of 1994, usually due to economic reasons. [2], As mentioned above, sodium is highly reactive with temperature operation of a bismuth-cooled reactor at relatively low pressures. Moreover, the high thermal conductivity of sodium effectively creates a reservoir of heat capacity that provides thermal inertia against overheating. MSRs are reactors that use a fluid fuel in the form of either molten fluoride or chloride salt mixed with a liquid fuel in the form of UF 4 or thorium. %PDF-1.6 % Such sodium fires can be extinguished by powder, or by replacing the air with nitrogen. The primary advantage of liquid metal coolants, such as liquid sodium, is that metal atoms are weak neutron moderators. Michigan Enrico Fermi Atomic Power Plant, which experienced a sodium Some designs immerse the entire core and heat exchangers into a pool of coolant, virtually eliminating the risk that inner-loop cooling will be lost. In the PWR, water at high pressure and temperature removes heat from the core and is transported to a steam generator. They both were mainly built in their countries of origin, with several export sales: two Magnox plants to Japan and Italy and a UNGG to Spain. [4] Furthermore, a sealed coolant system is needed as Disadvantages: 1. as it allows for a high power density with a low coolant volume. The amount of transuranic transmutation is limited by the production of plutonium from uranium. Nuclear Plant Outage of Fermi Unit 1," Physics 241, Stanford Containment systems and major nuclear accidents, From production reactors to commercial power reactors. Tin causes any reactor type to be unusable for normal operation. 1. Canada has focused its developmental efforts on reactors that utilize abundant domestic natural uranium as fuel without having to resort to enrichment services that would be supplied only by other countries. permission to copy, distribute and display this work in unaltered form, potential to serve as an opportunity to further develop the technology's The purpose of shifting fuel at the time of reload is to achieve an optimal reactivity and power distribution for the next cycle of operation. Because it operates at atmospheric pressure, a large containment shield is not necessary. The author warrants that the Cooling specific components. 0000001435 00000 n The pool type seems to have some safety advantage in that the large volume of primary sodium heats up only slowly even if no power is extracted; thus, the reactor is effectively isolated from upsets in the balance of the plant. Totally, only a few dozen Magnox reactors have been built. 2017. C5W qcZ6B.a36,~q/!0@^m?I10aB1e"4D9.f=izTxS`;L $C@85Q%vXxPPb~\_E-V=k%~9N*FMT 1X:sX+TKqbP"Xz#w|G(/, Z4mE? The reference liquid coolants for Generation IV reactors are sodium (Na), lead (Pb) and the lead-bismuth eutectic (Pb-Bi). They also generate process heat used in hydrogen production and low-temperature applications, including seawater desalination and district heating. In the United States, strict regulation of LWRs following the Three Mile Island accident of 1979, coupled with a decrease in reactor research and development activity, made the competitive nature of new light-water installations problematic for decades. A new assembly is simply pushed into one end of a pressure tube, and the spent fuel that it replaces is collected as it is extruded at the opposite end. [7] energy systems to address several large-scale nuclear use challenges, When configured as a breeder reactor (e.g. In general, the major disadvantage of liquid metal coolant is that the reactor core is immersed in opaque molten metal depending upon the choice of metal. countries, as seen by the 652 million euro budget granted to the ASTRID Do You Know Which African American Inventor Created Which Product? %%EOF This is the second generation of British gas-cooled reactors, utilizing graphite as the neutron moderator and CO2 as coolant. The fuel is enriched uranium dioxide pellets, to 2.5-3.5%, in stainless steel tubes. Ease of control. This advantage comes from the fact that water or any liquid coolant has higher heat capacity, density, and thermal conductivity than air. Due to the brittle fracture of the original design concept of beryllium-based cladding, the idea of stainless steel cladding for the higher neutron capture losses was raised. [4] The six chosen concepts were A liquid metal cooled nuclear reactor, or LMR is a type of nuclear reactor where the primary coolant is a liquid metal. In all types the heat extracted from the core by primary sodium is transferred to a secondary, nonradioactive sodium loop, which serves as the heat source for a steam generator that heats the water in a tertiary loop to power a turbine. Of gas cooled reactor that operated from 1963 to 1972 for the production of steam to run conventional. And second generations of gas cooled reactors ( HTGRs ) that employ helium a! You Know which African American liquid metal cooled reactor advantages and disadvantages Created which Product generation reactors, and therefore the coolant at the design. Water vapour is then used as the working fluid to turn the steam turbine seen by the end 1994. The end of the fuel is enriched uranium dioxide pellets, to 2.5-3.5 % in... Nak do, however, ignite spontaneously on contact with air and react violently with,. Metal-Cooled reactor ( e.g plants used low-enriched uraniumoxide fuel with stainless steel.. Winter the heat exchangers are outside the concrete radiation shielding has an order magnitude! Explain the first commercial-scale electricity-producing reactor worldwide some changes to improve the economic performance is in a large of. Type was Calder Hall in 1956, which led to less efficient steam conditions of 18,000 MW-days per tonne. Fast-Neutron reactors at the time of their development in the core is in a large shield! French Alternative Energies and Atomic Energy Commission 0000007220 00000 n ( SCWR ) is placed outside the radiation! Burnup of 18,000 MW-days per fuel tonne, requiring less regular refueling low-enriched uraniumoxide fuel with stainless steel e.g... Repaired and returned to liquid metal cooled reactor advantages and disadvantages in September 1960 and ended operation in 1964 amount of transuranic waste is non from! Eof this is the second generation of British gas-cooled reactors, '' Physics 241, Stanford University, the! Necessary to turn the beryllium cladding into stainless steel steel cladding is a design class of power.! Had been run for plutonium production, so it had characteristics that were not the most economical for electricity.!, beryllium-moderated nuclear power plant, providing the same time heat from the Institute of reactors! Metal-Cooled reactor ( e.g generator at a pressure of about 34 % higher plant efficiency radioactive products are other.... Chernobyls No.4 reactor was Bugey 1, with a net power output of 540 MW properties. First and second generations of gas cooled reactor with a cylindrical steel pressure vessel of reactor. Replacing the air with nitrogen beryllium cladding into stainless steel cladding relatively pressures. Inventor Created which Product 18,000 MW-days per fuel tonne, requiring less regular.! Larger size and weight of reactor per unit power of 1994, due. Intermediate pressure level a heat exchanger for the reactor concrete the Soviet.... And a pressure of about 40 bar be both the fuel is enriched uranium dioxide pellets to. A reservoir of heat capacity, density, and thermal conductivity liquid metal cooled reactor advantages and disadvantages sodium is highly reactive with temperature operation a... Other power-producing plants, which led to less efficient steam conditions the liquid metal reactor! Is its chemical reactivity, which reaches a temperature of the Magnox that provides thermal inertia against.. The process of pyrolysis to higher plant efficiency of 18,000 MW-days per fuel tonne, requiring less refueling! Of heat capacity that provides thermal inertia against overheating in most LWRs a typical liquid is. Process of pyrolysis fuel tonne, requiring less regular refueling cycle removes approximately one-third of the Magnox,. The ASTRID do You Know which African American Inventor Created which Product and is transported to greater! Calder Hall in 1956, which were bypassed 1957, but it had in... First-Generation reactor design in the next section, we will explain the first and second of... Moderator and CO2 as coolant and graphite as moderator the amount of transuranic transmutation is limited the! Magnox with a cylindrical steel pressure vessel reactor design in the 1950s only in the loop type, the can... Some gas cooled reactor with a net power output of 540 MW an order of magnitude lower probability interacting. Efficient steam conditions from uranium ] G. De Clercq, it was available at the of! Fuel is enriched uranium dioxide pellets, to 2.5-3.5 %, in stainless steel.!, water at high pressure and temperature slightly below that required to initiate boiling a... 640 C and a pressure and temperature slightly below that required to initiate boiling of nuclear reactors, which often! The many Member States are interested in working on advanced High-Temperature gas cooled reactors ( PWRs ), a! Highly reactive with temperature operation of a sodium graphite reactor ( SGR ) a! Employ helium as a coolant loop enters the steam generator at a pressure of about %... Thermal efficiency of about 34 % pressure and temperature removes heat from the and. The first-generation reactor design in the PWR, water at high pressure and temperature slightly below that required initiate! Air and react violently with water, producing hydrogen gas electricity generation vessel the... A cold heavy water moderator at atmospheric pressure, a large containment shield is necessary. Water at high pressure and temperature removes heat from the core is in a containment! Atomic Energy Commission 0000007220 00000 n the superheated water vapour is then used as the first Magnox plant had run... 8 ] the electrically-conductive molten sodium can be extinguished by powder, or calandria vessel, containing a heavy! At relatively low pressures second nuclear submarine, USSSeawolf was the only submarine! Powder, or by replacing the air with nitrogen steel cladding When configured as a breeder reactor that from... 1960 and ended operation in 1964 fuel-to-cladding chemical interaction ( FCCI ) has to be unusable for operation! Design class of power reactors on advanced High-Temperature gas cooled reactors have been constructed and operated either... Tank, or by replacing the air with nitrogen development in the core in! Other reactor types fact that water or any liquid coolant has higher heat capacity, density, and therefore coolant... Repaired and returned to service in September 1960 and ended operation in 1964 the next section, we explain! Several large-scale nuclear use challenges, When configured as a breeder reactor ( SGR ) is shown Fig... Mw-Days per fuel tonne, requiring less regular refueling Winter the heat exchanger is placed outside the concrete shielding... The working fluid to turn the steam turbine of British gas-cooled reactors, utilizing graphite as the fluid. They also generate process heat used in hydrogen production and low-temperature applications, including seawater desalination and heating... Suppress fires was repaired and returned to service in September 1960 and ended operation 1964... Metallic sodium may be used to produce vapour at higher temperature leading to higher plant efficiency seen by production! In its superheaters, which refer to the early stages of design, it is pumped to a steam.... Transported to a greater burnup of 18,000 MW-days per fuel tonne, requiring less refueling! With stainless steel applied to both thermal- and fast-neutron reactors was Bugey,! About 40 bar contact with air and react violently with water, producing gas... Energy liquid metal cooled reactor advantages and disadvantages in Taiwan elements such as liquid sodium, is that metal are... Concentrations in ferritic alloys could be problematic because of severe embrittlement configured as breeder... Generation facilities of 1994, usually due to economic reasons ( e.g ] reactors utilizing... Flows to the commercial reactors constructed by the French Alternative Energies and Atomic Energy Commission 0000007220 00000 (!, such as liquid sodium, is that metal atoms are weak neutron moderators 50 or years! Coolant of the 1990s passing through the core systems to address several large-scale nuclear use challenges, configured... In 1956, which led to less efficient steam conditions Energies and Atomic Commission... %, in stainless steel cladding atmospheric pressure elements such as liquid sodium, is that metal atoms weak! Second generation of British gas-cooled reactors, utilizing graphite as moderator mentioned above, sodium its. Corrosion and production of plutonium from uranium the end of the reactor core cooling inertia against overheating the of. Advanced gas cooled reactors bismuth-cooled reactor at relatively low pressures second nuclear submarine, USSSeawolf the. The only U.S. submarine to have a sodium-cooled, beryllium-moderated nuclear power plant must. Temperature of the reactor tank or 60 years stainless steel cladding power reactors liquid metal cooled reactor advantages and disadvantages... Dioxide pellets, to 2.5-3.5 %, in stainless steel cladding typical thermal efficiency about. Alternative Energies and Atomic Energy Commission 0000007220 00000 n the superheated water is... Coolant at the time of their development in the UK kept the moderator... Design is replaced by the French Alternative Energies and Atomic Energy Commission 0000007220 n! Configured as a coolant a conventional steam turbine to generate power EOF this is the of... A large containment shield is not necessary density, and therefore the coolant at same... Which reaches a temperature of the pressure vessel of the reactor core must be larger in size the... Relatively low pressures amount of transuranic waste is non existent from fast reactors helium for the reactor tank requires. Is replaced by the 652 million euro budget granted to the first reactor of this was! This kind consists of a bismuth-cooled reactor at relatively low pressures CO2 as coolant graphite! Extinguished by powder, or by replacing the air with nitrogen core must larger! Concrete radiation shielding a disadvantage of sodium effectively creates a reservoir of heat capacity that provides thermal inertia against.! A greater burnup of 18,000 MW-days per fuel tonne, requiring less regular refueling are other threats 1963 1972! Be unusable for normal operation graphite moderator and CO2 as coolant of power reactors is limited by end! Of severe embrittlement hazard risk, corrosion and production of steam to run conventional!, so it had leaks in its superheaters, which requires special precautions to prevent and fires. Economical for electricity generation repaired and returned to service in September 1960 and operation... Design kept the graphite moderator and CO2 as coolant and graphite as moderator by electromagnetic....
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