liquid metal cooled reactor advantages and disadvantages

Upon absorbing heat from the primary loop, however, it becomes saturated and ultimately slightly superheated. [4] "Overview of Generation IV (Gen IV) Reactor NaK was used as the coolant in the first breeder reactor prototype, the Experimental Breeder Reactor-1, in 1951. This 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]. 1, the SFR can achieve a core power density of around 300 MW/m3 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 2020 Natrium received an $80M grant from the US Department of Energy for development of its SFR. As the world's population continues to grow, the need Therefore, they are also called supercritical boilers. A reactor of this kind consists of a tank, or calandria vessel, containing a cold heavy water moderator at atmospheric pressure. The program plans to use High-Assay, Low Enriched Uranium fuel containing 5-20% uranium. IRSN 2012/158, September 2012. however, next generation nuclear reactors (i.e., Generation IV) have the The first generation of French nuclear power plants was UNGGs. The application of graphite neutron moderators in commercial gas cooled reactors leads to the absorption of fewer neutrons compared to water-moderated reactors. Accordingly, this variety is discussed in considerable detail here. 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 temperature operation of a bismuth-cooled reactor at relatively low pressures. While some LMRs are of the loop type, equipped with heat exchangers and pumps outside the primary reactor vessel, others are of the pool variety, featuring a large volume of primary sodium in a pool that also contains the primary pumps and the primary-to-secondary heat exchanger. work is the author's own and that Stanford University provided no input The UNGG, abbreviated form of Uranium Naturel Graphite Gaz, is an outdated design of nuclear power reactor developed in France. More Information on reusing IAEA copyright material. Since both claddings react with water, they may be stored in a spent fuel pool only shortly. other rights, including commercial rights, are reserved to the The result of this policy is the Canada Deuterium Uranium (CANDU) reactora line of natural uranium-fueled reactors moderated and cooled by heavy water. HWn0 *|SAh{ha\INTb"K /e26-9PxH*&ce$CYI1orq-R&j&`?2>E2GzkvQ}]l"pG+Nt]]WuY&$9V`9 OmtvesFq^UCGYAZk@.MrU2nfr>V]mkwmpsYR7r1}5 y`-.g9W`M cADLjLJ@ generator or cause a hydrogen explosion. Disadvantages: 1. 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. This makes them attractive for improving power output, cost effectiveness, and fuel efficiency in nuclear power plants. [8] The electrically-conductive molten sodium can be moved by electromagnetic pumps. The melting point can be lowered by alloying the lead with bismuth, but lead-bismuth eutectic is highly corrosive to most metals[4][5] used for structural materials. Much larger size and weight of reactor per unit power. 0000001256 00000 n Liquid metal cooled reactors were first adapted for breeder reactor power generation. In 2000 the High Temperature Reactor-10 (HTR-10), a Chinese reactor based on the German pebble-bed design, began operating at a nominal steady-state power level of 10 megawatts. '5Mhl8ljM%RVQ r qvpS)\GCnbM68&9q>#2q[a)P2t:9{ X4`jl6>!ZS]w.yT**sbF"Xh#={%_:0/ M\@. [4,5]. During the 1970s, light-water reactors represented the cheapest source of new electricity in most parts of the world, and it still is economical in many countries such as Japan, South Korea, Taiwan, France, and China (which, in the 1990s, embarked on an ambitious program of building nuclear power plants, almost all of them using light-water technology). endstream endobj 44 0 obj<> endobj 45 0 obj<>/Encoding<>>>>> endobj 46 0 obj<> endobj 47 0 obj<>/Font<>/ProcSet[/PDF/Text/ImageB]>> endobj 48 0 obj<>stream 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. Sodium and NaK do, however, ignite spontaneously on contact with air and react violently with water, producing hydrogen gas. [3] An If you would like to learn more about the IAEAs work, sign up for our weekly updates containing our most important news, multimedia and more. [7] B. Fleming, 3.12. trailer with attribution to the author, for noncommercial purposes only. The Sodium Reactor Experiment was an experimental sodium-cooled graphite-moderated nuclear reactor (A Sodium-Graphite Reactor, or SGR) sited in a section of the Santa Susana Field Laboratory then operated by the Atomics International division of North American Aviation. According to the numbers indicated in the figure, the names of the components of this reactor are as follows: The hot coolant means temperature exiting the reactor core was designed to be 648C. This allows for the coolant to operate at higher temperatures and lower pressures than current reactorsimproving the efficiency and safety of the system. primary sodium coolant does not directly exchange its heat with the The first Magnox plant had been run for plutonium production, so it had characteristics that were not the most economical for electricity generation. such as: [2,3], Deployable while minimizing risk of nuclear [6] C. Grandy, "US Department of Energy and Nuclear A Russian breeder reactor, the BN-600, reported 27 sodium leaks in a 17-year period, 14 of which led to sodium fires.[9]. This liquid takes heat from the heat exchanger and then passes through a boiler. The reference liquid coolants for Generation IV reactors are sodium (Na), lead (Pb) and the lead-bismuth eutectic (Pb-Bi). Was used to power a water de-salination plant. Most of them were constructed from the 1950s to the 1970s in the UK, and few were exported to other countries. The steam thus generated ultimately serves as the working fluid in a steam-turbine cycle. These are of the gas-to-water heat exchanger types that use the once-through fundamental to boil the flowing water. Your email address will not be published. The Calder Hall reactor design was fueled with slugs of natural uranium metal canned in aluminum, was cooled with carbon dioxide, and employed a moderator consisting of a block of graphite pierced by fuel channels. explosion that delayed the reactor's repairs after a partial core reactors including other types of fast reactors. A BWR operates on the principle of a direct power cycle. CANDU reactors Canada Deuterium Uranium reactor Since the 1980s, they have been the backbone of the nuclear power generation fleet of the UK. the sodium is highly reactive with air and water; however, the Calder Hall, the first nuclear station to feed an appreciable amount of power into a civilian network opened in 1956. On November 30, 2019, CTV reported that the Canadian provinces of New Brunswick, Ontario and Saskatchewan planned an announcement about a joint plan to cooperate on small sodium fast modular nuclear reactors from New Brunswick-based ARC Nuclear Canada. The pebble bed reactor contains fuel in the form of pebbles that are placed in a cylindrical pressure vessel. %PDF-1.6 % The main requirement among these was to operate with natural uranium and the need for a coolant with a low neutron cross-section, here carbon dioxide, and an effective neutron moderator, graphite. The second-generation reactor is a design class of nuclear reactors referring to the commercial reactors constructed by the end of the 1990s. 0000014282 00000 n And fire hazard risk, corrosion and production of radioactive products are other threats. completely thermalized, to convert U-238 into plutonium. On the other hand, even though the internals of the PWR are simpler, a BWR power plant is smaller, because it has no steam generators. 0000016376 00000 n A principal operational motivation for working on this technology is enhanced energy conversion efficiency provided by a higher reactor operating temperature. Several sodium-cooled fast reactors have been built and some are in current operation, particularly in Russia. Both are capable of operating at very high temperature, since graphite has an extremely high sublimation temperature and helium is completely inert chemically. Both reactors may put the fuel in an annulus section with a graphite center spire, according to the design and desired power of the reactor. Most LMRs are breeders or are capable of breeding, which is to say that they all produce more fissile material than they consume. Given the This process is repeated for each element that requires removal. Leak proof heat exchanger must be used, which increases extra cost. This was the case at the Monju Nuclear Power Plant in a 1995 accident. The arrangement of a sodium graphite reactor (SGR) is shown in Fig. <<47A499A70D1B7541B2195AAD6E7A23F4>]>> Two reactors being constructed on Changbiao Island in, Suspended for 15 years. In the United States, which does not reprocess, storage pools have continued to receive spent fuel, and some of the pools are filling up. 2. The Magnox also ran almost cooler gas temperatures than other power-producing plants, which led to less efficient steam conditions. In the next section, we will explain the first and second generations of gas cooled reactors. 0000012196 00000 n Indeed, the systems use of liquid metal provides a multitude of advantages due to the physical properties of the molten metal coolant. Light-water reactors are refueled by removing the reactor headafter lowering and unlatching the safety rods in the case of a PWR. Lead-Bismuth Fast Reactor: This liquid metal-cooled reactor (LMR) design from the Institute of Nuclear Energy Research in Taiwan . fuel system with another involves relative advantages and disadvantages. 0000001054 00000 n which allows the use of fast neutrons. This significantly resulted in an increase in the cost of the power production by an AGR. A Sodium-cooled Fast Reactor (SFR) is a type of Capacity factor refers to the ratio of time that a reactor is operating at full power during a given period versus the total available time during that same period. Crucially, when a reactor runs on fast neutrons, the plutonium isotopes are far more likely to fission upon absorbing a neutron. 66 0 obj<>stream FCCI causes the cladding to reduce in strength and even rupture. Most of the worlds existing reactors are power reactors, providing the heat needed to turn turbines that run electric-power generators. 0000004408 00000 n In fact, the steam generators of a PWRthere are typically four of them in a big plantare larger than the reactor vessel itself. Therefore, short-term reprocessing of the fuel is essential and requires highly shielded facilities for this. There are two principal types of HTGRs, including Pebble Bed Reactors (PBRs) and Prismatic Block Reactors (PMRs). Totally, only a few dozen Magnox reactors have been built. The high-temperature gas-cooled reactor (HTGR), as mentioned above in Fuel types, is fueled by a mixture of graphite and fuel-bearing microspheres. Production of superheated steam and excellent heat removal. secondary molten sodium stream can exchange its heat with water to Water passing through the core is allowed to boil at an intermediate pressure level. Aside from the Russian experience, Japan, India, China, France and the USA are investing in the technology. Over time, light-water reactors have tended to increase in size, reaching electric capacity ratings of 1,000 megawatts or more. 0000013241 00000 n "The sodium-based systems do not serve as neutron moderators, unlike water, Most LMRs are fueled with uranium dioxide or mixed uranium-plutonium dioxides. 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. The nuclear fuel cycle employs a full actinide recycle with two major options: One is an intermediate-size (150600MWe) sodium-cooled reactor with uranium-plutonium-minor-actinide-zirconium metal alloy fuel, supported by a fuel cycle based on pyrometallurgical reprocessing in facilities integrated with the reactor. Due to their high thermal conductivity, metal coolants remove heat effectively, enabling high power density. nuclear reactor. [6] In addition, However, it increased the cooling gas working temperature to enhance steam conditions. Reloading is a time-consuming operation. [7], In addition, sodium's fast and exothermic reaction Indeed, the systems use To reach these high temperatures, while ensuring useful graphite core life (due to readily oxidation of graphite in CO2 at high temperatures), a re-entrant coolant flow at the lower temperature of boiler outlet of 278 C is used to cool the graphite. Containment systems and major nuclear accidents, From production reactors to commercial power reactors. Thus, although the higher thermal efficiency is an advantage, the fuel is used less efficiently. Light-water reactors (LWRs) are power reactors that are cooled and moderated with ordinary water. 0000006272 00000 n 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]. Fast speed, large depth and small deformation. But, many second-generation reactors live up to 50 or 60 years. Regulatory Commission - Advanced Fuel Cycle Research and Development 0000002574 00000 n Sodium-Graphite Reactor (SGR) is a typical liquid metal cooled reactor that uses sodium as coolant and graphite as moderator. 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. This exposes the reactor to visual observation. If sodium comes into contact with water it reacts to produce sodium hydroxide and hydrogen, and the hydrogen burns in contact with air. This design utilizes fast neutron energies and is therefore referred to as a fast reactor. With the three percent market share, all are installed in the United Kingdom. 14. Sodium has high thermal conductivity, meaning that it can effectively remove heat from the fuel rods. Graphite is used as the moderator in this reactor. 0000005339 00000 n The magnesium-zirconium alloy was used as the fuel cladding material in the UNGG instead of the magnesium-aluminum alloy in Magnox. Lead-bismuth eutectic allows operation at lower temperatures while preventing the freezing of the metal coolant in a lower temperature range (eutectic point: 123.5 C / 255.3 F).[4][6]. [17], Most of these were experimental plants that are no longer operational. [1] Others are in planning or under construction. Most LMRs are breeders or are capable of breeding, which is to say that they all produce more fissile material than they consume. Multi-metal composite; Thermal management material; Battery box / tray; About Us; R&D; Events. A sodium-cooled fast reactor is a fast neutron reactor cooled by liquid sodium. compared with Pressurized Water Reactors (PWR) that achieve 100 There are several types of power reactors, but only one, the light-water reactor, is widely used. (GIF), an international collective representing 14 countries, has led [1] E. Xue, In comparison, a GCR can run at temperatures up to 800850C and yield a heat-to-electricity conversion efficiency of more than 40% using conventional steam turbine facilities or as high as 50% using a more advanced gas turbine apparatus. 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. 0000001435 00000 n 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. These types of reactors can obtain very high fuel utilization rates and work at high temperatures. [1] Disadvantages include difficulties associated with inspection and repair of a reactor immersed in opaque molten metal, and depending on the choice of metal, fire hazard risk (for alkali metals), corrosion and/or production of radioactive activation products may be an issue. Key to Nuclear's Future or an Element of Doubt, The The secondary loop contains an alloy of sodium and potassium in liquid form. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Linquipis a Professional Network for Equipment manufacturers, industrial customers, and service providers, Copyright 2022 Linquip Company. Gas cooled reactors utilize graphite as a neutron moderator and carbon dioxide as the coolant. The Encapsulated Nuclear Heat Source (ENHS) concept is a liquid metal-cooled reactor of 50 MWe being developed by the University of California. 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. water. NaK is liquid at room temperature. 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. 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. Moreover, the high thermal conductivity of sodium effectively creates a reservoir of heat capacity that provides thermal inertia against overheating. Electric-power generation is obtained through the transfer of the heat of fission into the heavy-water coolant, which is circulated to a steam generator. Each reactor has a design thermal power generation of 1,500 MW which drives a 660 MW electrical power generation set. The saturated steam that exits the core region is transported through a series of separators and dryers located within the reactor vessel that promote a superheated state. [5] G. De Clercq, Additionally, the high temperature of the liquid metal can be used to drive power conversion cycles with high thermodynamic efficiency. 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. Key to Nuclear's Future or an Element of Doubt," Reuters, 13 Oct reactors, and therefore the coolant must have very good heat transfer properties. Hence, the salt can be both the fuel and the coolant at the same time. Some attention is also given to the prospective uses of reactors for space travel and for certain industrial purposes. Amongst different emerging energy technologies, nuclear energy The second is a medium to large (5001,500MWe) sodium-cooled reactor with mixed uranium-plutonium oxide fuel, supported by a fuel cycle based upon advanced aqueous processing at a central location serving multiple reactors. Pyroprocessing has several advantages for fast reactors which greatly simplify waste management and closing the fuel cycle. In all of these industries, brine chillers offer several advantages over other cooling methods, including high efficiency, reliability, and low cost.

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