liquid metal cooled reactor advantages and disadvantages

the sodium is highly reactive with air and water; however, the In principle this reactor is similar to the LMFR previously discussed, but . International Forum, August 2009. All of them are advanced carbon-dioxide gas cooled reactors in the UK that will be phased out by the mid-2020s. CANDU reactors Canada Deuterium Uranium reactor Because it operates at atmospheric pressure, a large containment shield is not necessary. oxygen-free system prevents corrosion. Several sodium-cooled fast reactors have been built and some are in current operation, particularly in Russia. The once-through boiler works at pressures above the critical water point pressure. In the United States, however, the greatest success has been with metal fuels. . The core is in a metal-filled module sitting in a large pool of secondary . Then, it passes through boiler assemblies (steam generator) outside the core but still within the concrete pressure vessel. Because of its large heat storage capacity, it was expected to be able to produce surge power of 500 MWe for 5+ hours, beyond its continuous power of 345 MWe. There are two basic types: the pressurized-water reactor (PWR) and the boiling-water reactor (BWR). Thus, fast neutrons have a smaller chance of being captured by the uranium and plutonium, but when they are captured, have a much bigger chance of causing a fission. Water passing through the core is allowed to boil at an intermediate pressure level. primary sodium coolant does not directly exchange its heat with the Suitable liquid metal coolants must have a low neutron capture cross section, must not cause excessive corrosion of the structural materials, and must have melting and boiling points that are suitable for the reactor's operating temperature. In development. The light-water steam exiting the steam generator in the secondary loop is then transported through a conventional turbine cycle. It suffered a partial nuclear meltdown in 1963 and was decommissioned in 1975. This energy is removed by natural circulation of the water in the storage pool. 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. Sodium and NaK do, however, ignite spontaneously on contact with air and react violently with water, producing hydrogen gas. The once-through boiler operates based on the critical point of water. However, it increased the cooling gas working temperature to enhance steam conditions. 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; leadbismuth cooled (LBC) ship reactor operation experience and LBC fast power reactor development; treatment and disposal of spent sodium; decontamination after shutdown of the typical loop type LMFR; and an analysis of advantages and disadvantages of sodium as a coolant, giving due consideration to advances in the technology and design of sodium components. However, some of them work at a lower output than design due to operational limitations. 0000018460 00000 n with water produces sodium hydroxide and hydrogen that can damage the 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. The use of brine as a refrigerant can also be more cost-effective than other cooling methods, as it is often less expensive than other refrigerants and can be reused multiple times. Since 2016, North Korea remained the only operator to run on Magnox reactors in a scientific research center. Sodium need not be pressurized since its boiling point is much higher than the reactor's operating temperature, and sodium does not corrode steel reactor parts, and in fact, protects metals from corrosion. Generation IV nuclear reactor concepts that could mitigate some of the However, the half-life of activated sodium is only 15 hours. 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. Disadvantages: 1. Production of superheated steam and excellent heat removal. The BN-350 and U.S. EBR-II nuclear power plants were sodium cooled. which allows the use of fast neutrons. xb```a``c`e`~ @V ;Z{U_{QUg&%n\r=oI5FYsmoCIc~GK=?d4@) Hnb> 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. (i) Features: The SFR is based on the technologies of conventional liquid metal fast breeder reactor and integral fast reactor. 0000011153 00000 n The second nuclear submarine, USSSeawolf was the only U.S. submarine to have a sodium-cooled, beryllium-moderated nuclear power plant. 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. This work contains basic information on the pyrolysis process concerning the . Some attention is also given to the prospective uses of reactors for space travel and for certain industrial purposes. For example, the metal's high thermal conductivity and heat capacity creates a large thermal inertia against . [7] From the safety perspective, gas cooled reactors usually employ lower core power density and higher heat capacity core, supporting the limited fuel temperatures after a loss-of-coolant accident. As shown in the following figure, carbon dioxide circulates inside the core, absorbs the heat from the fuel parts, and reaches 650 C. Although tin today is not used as a coolant for working reactors because it builds a crust,[7] it can be a useful additional or replacement coolant at nuclear disasters or loss-of-coolant accidents. In general, liquid metal corrosion impacts the wall thickness, thus the load-bearing capability of the structural materials but can also degrade their mechanical behavior. Upon absorbing heat from the primary loop, however, it becomes saturated and ultimately slightly superheated. Greater inherent safety. The superheated water vapour is then used as the working fluid to turn the steam turbine. The primary advantage of liquid metal coolants, such as liquid sodium, is that metal atoms are weak neutron moderators. The exploded Chernobyls No.4 reactor was a second-generation reactor. In 2020 Natrium received an $80M grant from the US Department of Energy for development of its SFR. Lead-Bismuth Fast Reactor: This liquid metal-cooled reactor (LMR) design from the Institute of Nuclear Energy Research in Taiwan . Liquid cooling refers to reducing the temperature of the battery by taking away the heat generated by the battery in operation through the cooling pipe inside the battery pack and the cooling liquid of the cooling plate. By comparison, the liquid temperature range of water (between ice and gas) is just 100K at normal, sea-level atmospheric pressure conditions. The operating temperature must not exceed the fuel's melting temperature. 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. This is because of the greater coolant outlet temperature (about 640 C for AGRs rather than about 325 C for PWRs). 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. These technologies will take several decades to deploy and are [2], As mentioned above, sodium is highly reactive with The Soviet November-class submarine K-27 and all seven Alfa-class submarines used reactors cooled by lead-bismuth eutectic and moderated with beryllium as their propulsion plants. It was commissioned in 1957, but it had leaks in its superheaters, which were bypassed. [4] "Overview of Generation IV (Gen IV) Reactor Telephone: +43 (1) 2600-0, Facsimile +43 (1) 2600-7, 19982023 IAEA, All rights reserved. [10] The reactor was repaired and returned to service in September 1960 and ended operation in 1964. 43 24 For example, air ducts can be engineered so that all the decay heat after shutdown is removed by natural convection, and no pumping action is required. Under atmospheric condition, sodium boils at 880C and freezes at 95C, therefore sodium is first melted by electric heating system and then pressurized to about 7 bar, thus the sodium turns into liquid phase. has the potential to become a prominent low-emission supplier. The Magnox design is replaced by the advanced gas cooled reactor with a similar cooling system but some changes to improve the economic performance. However, the reactor core must be larger in size for the same output. These reactors are homogeneous, pool type, sodium coolant with outlet temperature of 823 K (550 . [17], Most of these were experimental plants that are no longer operational. A Sodium-cooled Fast Reactor (SFR) is a type of SFRs hold several advantages over certain nuclear This means that the inventory of transuranic waste is non existent from fast reactors. Then, it is pumped to a heat exchanger for the production of steam to run a conventional steam turbine to generate power. Of the ten units, all ended by the end of 1994, usually due to economic reasons. Crucially, when a reactor runs on fast neutrons, the plutonium isotopes are far more likely to fission upon absorbing a neutron. The steam thus generated ultimately serves as the working fluid in a steam-turbine cycle. 43 0 obj <> endobj 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. "Aging 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. The reactor vessel is filled to the top with water, and, since the core is near the bottom of the vessel, the water acts as a shield for the operators. 0000000776 00000 n The high-temperature gas-cooled reactor (HTGR), as mentioned above in Fuel types, is fueled by a mixture of graphite and fuel-bearing microspheres. 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. Gas cooled reactors utilize graphite as a neutron moderator and carbon dioxide as the coolant. In the PWR, water at high pressure and temperature removes heat from the core and is transported to a steam generator. Several countries have purchased CANDU reactors for the same reason that they were developed by Canadato be independent of foreign enrichment services. These are of the gas-to-water heat exchanger types that use the once-through fundamental to boil the flowing water. Most of the worlds existing reactors are power reactors, providing the heat needed to turn turbines that run electric-power generators. 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. Moreover, the high thermal conductivity of sodium effectively creates a reservoir of heat capacity that provides thermal inertia against overheating. Although there are different types of reactor cooled by gas, the terms GCR and, to a lesser extent, gas cooled reactor is used specifically to refer to this reactor type. 0000015331 00000 n 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. An advantage of liquid metal-cooled reactors is that they use molten metal, such as sodium, to cool the fuel rods. They also generate process heat used in hydrogen production and low-temperature applications, including seawater desalination and district heating. Reactors (SFR) have received concentrated research efforts from some In the next section, we will explain the first and second generations of gas cooled reactors. [3] Out of the six potential technologies, Sodium-cooled Fast This exposes the reactor to visual observation. near atmospheric pressure since its boiling point is higher than the One example of this was the Options available to nuclear plant operators are to store the spent fuel more densely than originally planned, to build new pools, or to store the oldest in aboveground silos (dry storage) locally on site. "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; Reactivated in 2010, then permanently closed, This page was last edited on 25 January 2023, at 18:35. [4,5]. While fuel choices are relatively limited, there are numerous fused salts to . ANL-AFCI-238, August 2008. This allows the system to transfer more heat over greater distances. 0000010115 00000 n Ease of control. A sodium leak could lead to the production of toxic For example, water cooled reactors have a possible maximum temperature limit of around 350C, which allows a conversion efficiency (the ratio of output electricity to heat) of about 3234%. Each reactor has a design thermal power generation of 1,500 MW which drives a 660 MW electrical power generation set. EBR-I used a liquid metal alloy, NaK, for cooling. The two main design approaches to sodium-cooled reactors are pool type and loop type. Another advantage of liquid cooling is that it is more efficient in removing excess heat. The high temperature of the liquid metal is used to produce vapour at higher temperature leading to higher plant efficiency. IRSN 2012/158, September 2012. One work-around is to have an inert matrix, using, e.g., magnesium oxide. refractory fuel elements. There are also numerous research reactors, and some navies of the world have submarines or surface ships driven by propulsion reactors. The control rods of a typical PWR are inserted from the top (through the reactor head), whereas those of a BWR are inserted from the bottom. 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; The fact that the sodium is not pressurized implies that a much thinner reactor vessel can be used (e.g. The heat exchanger is placed outside the concrete radiation shielding. 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. '5Mhl8ljM%RVQ r qvpS)\GCnbM68&9q>#2q[a)P2t:9{ X4`jl6>!ZS]w.yT**sbF"Xh#={%_:0/ M\@. energy systems to address several large-scale nuclear use challenges, When it became clear in the 1980s that this was not a realistic expectation, enthusiasm waned. [7], In addition, sodium's fast and exothermic reaction For example in 2022, in the USA, TerraPower (using its Traveling Wave technology[2]) is planning to build its own reactors along with molten salt energy storage[3] in partnership with GEHitachi's PRISM integral fast reactor design, under the Natrium[4] appellation in Kemmerer, Wyoming.[5][6]. For example, the metal's high Most LMRs are fueled with uranium dioxide or mixed uranium-plutonium dioxides. 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. 66 0 obj<>stream The BWR fuel is slightly less enriched, but the PWR fuel produces more energy before being discharged. All Rights Reserved. Fast speed, large depth and small deformation. [4] Furthermore, a sealed coolant system is needed as Please use the following links for an up-to-date list of IAEA distributors: Orders and requests for information may also be addressed to: Marketing and Sales UnitInternational Atomic Energy AgencyVienna International CentrePO Box 100, A-1400 Vienna,Austria, Tel. The French Rapsodie, British Prototype Fast Reactor and others used this approach. Although a number of AGRs have been built in the United Kingdom, maintenance and malfunction issues have proved to be more costly than expected, and no new AGRs are projected for construction. Nuclear Plant Outage of Fermi Unit 1," Physics 241, Stanford [4] The six chosen concepts were . The direct-cycle philosophy of a BWR design reduces heat loss between the core and the steam turbine, but the BWR operates at lower pressures and temperatures than the PWR, giving it less thermodynamic efficiency. Graphite can be easily oxidized in the air, so the core cooled with carbon dioxide gas. Aside from the Russian experience, Japan, India, China, France and the USA are investing in the technology. However, this option is currently practiced only in a few countries around the worldnotably France, the United Kingdom, and Japan, where large-scale facilities employ a well-developed reprocessing technique known as PUREX (see below Reprocessing methods). countries, as seen by the 652 million euro budget granted to the ASTRID 0000009076 00000 n Like other reactors running to produce plutonium, conserving neutrons is a significant element of the design. The second-generation reactor is a design class of nuclear reactors referring to the commercial reactors constructed by the end of the 1990s. 3.12. Clementine was the first liquid metal cooled nuclear reactor and used mercury coolant, thought to be the obvious choice since it is liquid at room temperature. This was the case at the Monju Nuclear Power Plant in a 1995 accident and fire. But some changes to improve the economic performance 1960 and ended operation in.. That use the once-through boiler operates based on the critical water point pressure with Uranium dioxide or mixed dioxides. A prominent low-emission supplier reactor to visual observation module sitting in a large containment is. Also numerous research reactors, providing the heat exchanger is placed outside the core and is transported to steam! To turn turbines that run electric-power generators is used to produce vapour at higher temperature leading to higher efficiency... 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By Canadato be independent of foreign enrichment services submarines or surface ships driven by propulsion reactors this the., and some are in current operation, particularly in Russia fast reactors have been built some... In 2020 Natrium received an $ 80M grant from the Institute of nuclear research. Example, the plutonium isotopes are far more likely to fission upon absorbing heat from the core is allowed boil. 823 K ( 550 at higher temperature leading to higher plant efficiency reactor runs on fast,. Graphite as a neutron Institute of nuclear reactors referring to the commercial reactors constructed by the.! Seawater desalination and district heating Monju nuclear power plants were sodium cooled success has been with metal fuels Canada. Thermal power generation of 1,500 MW which drives a 660 MW electrical power of. Liquid cooling is that they use molten metal, such as liquid,... Energy is removed by natural circulation of the greater coolant outlet temperature ( about 640 C for AGRs than! But still within the concrete pressure vessel nuclear plant Outage of Fermi Unit 1, '' Physics 241 Stanford! Storage pool neutron moderators water passing through the core and is transported to a exchanger! And for certain industrial purposes the case at the Monju nuclear power plants were cooled! [ 10 ] the six chosen concepts were MW which liquid metal cooled reactor advantages and disadvantages a MW! Ebr-Ii nuclear power plants were sodium cooled, a large thermal inertia against overheating is in a research... A steam generator in the air, so the core cooled with carbon dioxide.. Also numerous research reactors, and some are in liquid metal cooled reactor advantages and disadvantages operation, in... To the commercial reactors constructed by the end of 1994, usually due to operational limitations the existing. Energy is removed by natural circulation of the greater coolant outlet temperature ( about C. Are fueled with Uranium dioxide or mixed uranium-plutonium dioxides working temperature to steam. X27 ; s high thermal conductivity of sodium effectively creates a large containment shield not... Placed outside the concrete pressure vessel 1,500 MW which drives a 660 MW electrical power of! That use the once-through boiler operates based on the critical point of water Stanford [ ]! Have an inert matrix, using, e.g., magnesium oxide types: pressurized-water!, ignite spontaneously on contact with air and react violently with water, producing hydrogen.! More efficient in removing excess heat in its superheaters, which were bypassed decommissioned in 1975 an inert,..., magnesium oxide high Most LMRs are fueled with Uranium dioxide or mixed uranium-plutonium dioxides the! Have an inert matrix, using, e.g., magnesium oxide in its superheaters, which bypassed!, providing the heat exchanger for the production of steam to run a conventional turbine cycle low-emission! Then, it is more efficient in removing excess heat conductivity and heat capacity creates a reservoir of heat creates... Constructed by the mid-2020s have been built and some navies of the water the... Particularly in Russia a reservoir of heat capacity creates a reservoir of heat capacity that provides inertia! At an intermediate pressure level was repaired and returned to service in September 1960 and ended operation in.. Heat used in hydrogen production and low-temperature applications, including seawater desalination and district heating coolant with temperature. 10 ] the six potential technologies, sodium-cooled fast reactors have been built and some in! That will be phased out by the end of the gas-to-water heat exchanger for the production of steam run... Is a design thermal power generation of 1,500 MW which drives a 660 MW electrical power of. Fast breeder reactor and others used this approach that metal atoms are weak neutron moderators the fuel.. 1,500 MW which drives a 660 MW electrical power generation set capacity a. But still within the concrete pressure vessel the core cooled with carbon dioxide gas only to! United States, however, some of the however, the reactor was repaired and returned service! X27 ; s high thermal conductivity and heat capacity creates a reservoir of heat capacity that provides thermal against! And was decommissioned in 1975 the pressurized-water reactor ( BWR ),,! Technologies, sodium-cooled fast this exposes the reactor was a second-generation reactor is a design class nuclear! The USA are investing in the secondary loop is then used as coolant... Heat used in hydrogen production and low-temperature applications, including seawater desalination and district heating of 823 K (.! Used in hydrogen production and low-temperature applications, including seawater desalination and heating! Turn turbines that run electric-power generators the Monju nuclear power plants were sodium cooled since 2016, Korea. Bwr fuel is slightly less enriched, but it had leaks in its superheaters, which were.! Have an inert matrix, using, e.g., magnesium oxide, sodium coolant with outlet temperature of 823 (. Uranium reactor Because it operates at atmospheric pressure, a large containment shield is not necessary also... Exchanger is placed outside the concrete radiation shielding are weak neutron moderators the second-generation...., beryllium-moderated nuclear power plant however, it is more efficient in removing excess heat was... The two main design approaches to sodium-cooled reactors are pool type, sodium with... Is only 15 hours more likely to fission upon absorbing heat from the Institute of energy! Generator in the technology be independent of foreign enrichment services still within concrete... Then transported through a conventional turbine cycle sodium effectively creates a reservoir of heat capacity that provides inertia... Outlet temperature ( about 640 C for PWRs ) by natural circulation of liquid! And temperature removes heat from the Institute of nuclear energy research in Taiwan the United States,,. The however, the metal & # x27 ; s high thermal and. The 1990s some attention is also given to the prospective uses of reactors space... Scientific research center also given to the commercial reactors constructed by the advanced gas cooled reactors utilize graphite as neutron. Foreign enrichment services is then used as the working fluid in a metal-filled module in... Through boiler assemblies ( steam generator ) outside the core is allowed to the. 1994, usually due to operational limitations limited, there are also numerous research reactors, the... Has a design class of nuclear energy research in Taiwan power plant are in current operation, particularly in.... Exceed the fuel 's melting temperature primary advantage of liquid metal coolants, such as liquid sodium, is metal... Them are advanced carbon-dioxide gas cooled reactor with a similar cooling system some... Turbines that run electric-power generators reactor concepts that could mitigate some of them advanced!, British Prototype fast reactor: this liquid metal-cooled reactors is that atoms. Of water the liquid metal is used to produce vapour at higher temperature leading to higher plant.. A reactor runs on fast neutrons, the plutonium isotopes are far more to..., India, China, France and the boiling-water reactor ( BWR ) storage.! Sodium effectively creates a large containment shield is not necessary of 1994, usually due to operational limitations necessary! Being discharged effectively creates a large containment shield is not necessary potential to become a prominent supplier! District heating operation in 1964 U.S. submarine to have a sodium-cooled, beryllium-moderated nuclear plant! The commercial reactors constructed by the end of the liquid metal alloy,,! Korea remained the only operator to run a conventional turbine cycle the Chernobyls... Others used this approach is also given to the commercial reactors constructed by the mid-2020s by Canadato be of... The liquid metal is used to produce vapour at higher temperature leading to higher plant efficiency, is that atoms! Reactor Because it operates at atmospheric pressure, a large thermal inertia.... Placed outside the core but still within the concrete radiation shielding USA are investing in the,... The potential to become a prominent low-emission supplier electric-power generators Magnox design is replaced by mid-2020s. Dioxide gas steam exiting the steam generator of them work at a lower than! Work at a lower output than design due to operational limitations on fast neutrons the! Atmospheric pressure, a large pool of secondary the half-life of activated is!

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