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93-435: The project is owned by Guangdong Taishan Nuclear Power Joint Venture Company Limited (TNPC), which is 70% owned by China Guangdong Nuclear Power Group (CGNPC) and 30% by Électricité de France (EDF). The plant's twin reactors each have a nameplate capacity of 1750 MWe. Its Arabelle generators are the largest single-piece electrical generators in the world, each weighing 495 tonnes and built by Dongfang Electric . Of

186-402: A black semiconducting solid. It can be made by heating uranyl nitrate to form UO 2 . This is then converted by heating with hydrogen to form UO 2 . It can be made from enriched uranium hexafluoride by reacting with ammonia to form a solid called ammonium diuranate , (NH 4 ) 2 U 2 O 7 . This is then heated ( calcined ) to form UO 3 and U 3 O 8 which

279-432: A fuel would be so expensive it is likely that the fuel would require pyroprocessing to enable recovery of the N. It is likely that if the fuel was processed and dissolved in nitric acid that the nitrogen enriched with N would be diluted with the common N. Fluoride volatility is a method of reprocessing that does not rely on nitric acid, but it has only been demonstrated in relatively small scale installations whereas

372-478: A fund run by China Guangdong Nuclear Power Group signed a deal raising US$ 1.03 billion for nuclear and related energy projects. Guangdong Nuclear's fund, the first industrial fund set up by a state-owned enterprise with approval from the State Council signed the fund-raising agreement with Bank of China , China Development Bank and other institutions, which will become shareholders in the fund. The financing

465-645: A further design evolution to a Generation III level, the ACPR-1000 , which would also replace intellectual property right-limited components from the CPR-1000. CGNPG aimed to be able to independently market the ACPR-1000 for export by 2013. CGNPG has been conducting the development work in cooperation with Dongfang Electric , Shanghai Electric , Harbin Electric , China First Heavy Industries and China Erzhong . The core of

558-511: A higher neutron cross section than U . As the Pu accumulates the chain reaction shifts from pure U at initiation of the fuel use to a ratio of about 70% U and 30% Pu at the end of the 18 to 24 month fuel exposure period. Mixed oxide , or MOX fuel , is a blend of plutonium and natural or depleted uranium which behaves similarly (though not identically) to the enriched uranium feed for which most nuclear reactors were designed. MOX fuel

651-453: A kernel of UO X fuel (sometimes UC or UCO), which has been coated with four layers of three isotropic materials deposited through fluidized chemical vapor deposition (FCVD). The four layers are a porous buffer layer made of carbon that absorbs fission product recoils, followed by a dense inner layer of protective pyrolytic carbon (PyC), followed by a ceramic layer of SiC to retain fission products at elevated temperatures and to give

744-613: A properly designed reactor. Two such reactor designs are the prismatic-block gas-cooled reactor (such as the GT-MHR ) and the pebble-bed reactor (PBR). Both of these reactor designs are high temperature gas reactors (HTGRs). These are also the basic reactor designs of very-high-temperature reactors (VHTRs), one of the six classes of reactor designs in the Generation IV initiative that is attempting to reach even higher HTGR outlet temperatures. TRISO fuel particles were originally developed in

837-859: A similar design to the CANDU but built by German KWU was originally designed for non-enriched fuel but since switched to slightly enriched fuel with a U content about 0.1 percentage points higher than in natural uranium. Various other nuclear fuel forms find use in specific applications, but lack the widespread use of those found in BWRs, PWRs, and CANDU power plants. Many of these fuel forms are only found in research reactors, or have military applications. Magnox (magnesium non-oxidising) reactors are pressurised, carbon dioxide –cooled, graphite - moderated reactors using natural uranium (i.e. unenriched) as fuel and Magnox alloy as fuel cladding. Working pressure varies from 6.9 to 19.35 bars (100.1 to 280.6 psi) for

930-476: A typical core loading is on the order of 4500–6500 bundles, depending on the design. Modern types typically have 37 identical fuel pins radially arranged about the long axis of the bundle, but in the past several different configurations and numbers of pins have been used. The CANFLEX bundle has 43 fuel elements, with two element sizes. It is also about 10 cm (4 inches) in diameter, 0.5 m (20 in) long and weighs about 20 kg (44 lb) and replaces

1023-399: A typical spent fuel assembly still exceeds 10,000 rem/hour, resulting in a fatal dose in just minutes. Two main modes of release exist, the fission products can be vaporised or small particles of the fuel can be dispersed. Post-Irradiation Examination (PIE) is the study of used nuclear materials such as nuclear fuel. It has several purposes. It is known that by examination of used fuel that

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1116-404: A way as to ensure low contamination with non-radioactive carbon (not a common fission product and absent in nuclear reactors that don't use it as a moderator ) then fluoride volatility could be used to separate the C produced by producing carbon tetrafluoride . C is proposed for use in particularly long lived low power nuclear batteries called diamond batteries . Much of what

1209-474: Is AREVA's 17x17 AFA 3G M5, which can be fabricated in China. Other features include has a design life that could extend beyond 40 years and an 18-month fuel cycle. It has a digital instrumentation and control system, and is equipped with hydrogen recombiners and containment spray pumps. Some CPR-1000 intellectual property rights are retained by Areva , which limits overseas sales potential. In 2010, CGNPG announced

1302-475: Is able to release xenon gas, which normally acts as a neutron absorber ( Xe is the strongest known neutron poison and is produced both directly and as a decay product of I as a fission product ) and causes structural occlusions in solid fuel elements (leading to the early replacement of solid fuel rods with over 98% of the nuclear fuel unburned, including many long-lived actinides). In contrast, molten-salt reactors are capable of retaining

1395-487: Is an alternative to low enriched uranium (LEU) fuel used in the light water reactors which predominate nuclear power generation. Some concern has been expressed that used MOX cores will introduce new disposal challenges, though MOX is a means to dispose of surplus plutonium by transmutation . Reprocessing of commercial nuclear fuel to make MOX was done in the Sellafield MOX Plant (England). As of 2015, MOX fuel

1488-477: Is as high as 90%. CNNC has said its active and passive safety systems, double-layer containment and other technologies meet the highest international safety standards. CNNC plans to start building Hualong Two by 2024. It will be a more economical version using similar technology, taking a year less to build with about a quarter less in construction costs. In November 2007, CGN signed a contract with Areva to build Taishan nuclear station with Areva's EPR , making

1581-489: Is commonly composed of enriched uranium sandwiched between metal cladding. Plate-type fuel is used in several research reactors where a high neutron flux is desired, for uses such as material irradiation studies or isotope production, without the high temperatures seen in ceramic, cylindrical fuel. It is currently used in the Advanced Test Reactor (ATR) at Idaho National Laboratory , and the nuclear research reactor at

1674-410: Is compacted to cylindrical pellets and sintered at high temperatures to produce ceramic nuclear fuel pellets with a high density and well defined physical properties and chemical composition. A grinding process is used to achieve a uniform cylindrical geometry with narrow tolerances. Such fuel pellets are then stacked and filled into the metallic tubes. The metal used for the tubes depends on the design of

1767-590: Is done is the ITU which is the EU centre for the study of highly radioactive materials. Materials in a high-radiation environment (such as a reactor) can undergo unique behaviors such as swelling and non-thermal creep. If there are nuclear reactions within the material (such as what happens in the fuel), the stoichiometry will also change slowly over time. These behaviors can lead to new material properties, cracking, and fission gas release. The thermal conductivity of uranium dioxide

1860-566: Is formed into pellets and inserted into Zircaloy tubes that are bundled together. The Zircaloy tubes are about 1 centimetre (0.4 in) in diameter, and the fuel cladding gap is filled with helium gas to improve heat conduction from the fuel to the cladding. There are about 179–264 fuel rods per fuel bundle and about 121 to 193 fuel bundles are loaded into a reactor core. Generally, the fuel bundles consist of fuel rods bundled 14×14 to 17×17. PWR fuel bundles are about 4 m (13 ft) long. In PWR fuel bundles, control rods are inserted through

1953-450: Is known about uranium carbide is in the form of pin-type fuel elements for liquid metal fast reactors during their intense study in the 1960s and 1970s. Recently there has been a revived interest in uranium carbide in the form of plate fuel and most notably, micro fuel particles (such as tristructural-isotropic particles). The high thermal conductivity and high melting point makes uranium carbide an attractive fuel. In addition, because of

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2046-413: Is low; it is affected by porosity and burn-up. The burn-up results in fission products being dissolved in the lattice (such as lanthanides ), the precipitation of fission products such as palladium , the formation of fission gas bubbles due to fission products such as xenon and krypton and radiation damage of the lattice. The low thermal conductivity can lead to overheating of the center part of

2139-659: Is made in France at the Marcoule Nuclear Site , and to a lesser extent in Russia at the Mining and Chemical Combine , India and Japan. China plans to develop fast breeder reactors and reprocessing. The Global Nuclear Energy Partnership was a U.S. proposal in the George W. Bush administration to form an international partnership to see spent nuclear fuel reprocessed in a way that renders

2232-432: Is now independent) was contracted to develop the nuclear island (including reactor) and supply fuel for 15 years, as well as providing technology transfer and engineering services. In December 2017, Hong Kong media reported that a "boiler" had cracked during testing, and that welding on the component was considered "problematic". Neither the nuclear plant's operators nor the manufacturer of the affected component responded to

2325-482: Is the first of two phases for the fund, which plans to raise a total of 10 billion yuan. In May 2013, the organization changed its name to China General Nuclear Power Group (CGN) to signify that its operations extend beyond Guangdong province. In December 2014, CGN raised $ 3 billion by an initial public offering (IPO) in Hong Kong . In December 2014, the firm announced it was acquiring three wind farms in

2418-418: Is then converted by heating with hydrogen or ammonia to form UO 2 . The UO 2 is mixed with an organic binder and pressed into pellets. The pellets are then fired at a much higher temperature (in hydrogen or argon) to sinter the solid. The aim is to form a dense solid which has few pores. The thermal conductivity of uranium dioxide is very low compared with that of zirconium metal, and it goes down as

2511-581: Is to try to thwart the country’s ' Made in China 2025 ' and was part of the US-China trade war". In November 2020, Donald Trump issued an executive order prohibiting any American company or individual from owning shares in companies that the United States Department of Defense has listed as having links to the People's Liberation Army , which included CGN. CGN's proposals to operate two nuclear plants in

2604-399: Is used by nuclear power stations or other nuclear devices to generate energy. For fission reactors, the fuel (typically based on uranium ) is usually based on the metal oxide ; the oxides are used rather than the metals themselves because the oxide melting point is much higher than that of the metal and because it cannot burn, being already in the oxidized state. Uranium dioxide is

2697-529: The C concentration will be too low for use in nuclear batteries without enrichment. Nuclear graphite discharged from reactors where it was used as a moderator presents the same issue. Liquid fuels contain dissolved nuclear fuel and have been shown to offer numerous operational advantages compared to traditional solid fuel approaches. Liquid-fuel reactors offer significant safety advantages due to their inherently stable "self-adjusting" reactor dynamics. This provides two major benefits: virtually eliminating

2790-452: The Pu is 'burned' in the reactor, providing about one third of the total energy. It behaves like U and its fission releases a similar amount of energy. The higher the burnup , the more plutonium is present in the spent fuel, but the available fissile plutonium is lower. Typically about one percent of the used fuel discharged from a reactor is plutonium, and some two thirds of this is fissile (c. 50% Pu , 15% Pu ). Metal fuels have

2883-649: The Government of Malaysia and the arrest of Malaysian Prime Minister Najib Razak for corruption and fraud. CGN is a state-owned enterprise supervised by the State Council via the State-Owned Assets Supervision and Administration Commission . CGN has been sanctioned by the United States for attempting to acquire advanced U.S. nuclear technology to divert to military uses in China. In 2016,

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2976-556: The M310 , CGN developed an improved Generation II pressurized water reactor called CPR-1000 . CPR-1000 takes a large proportion in all the reactors being built in China. The M310 uses as its base design units 5 & 6 of the Gravelines Nuclear Power Station in France. The CPR-1000 has a 1086 MWe capacity, a three-loop design and 157 fuel assemblies (active length 12ft), enriched to 4.5% U-235. The fuel assembly design

3069-469: The SASAC of the State Council . In China, CGN operates nuclear plants at Daya Bay Nuclear Power Plant , Ling Ao Nuclear Power Plant , Hongyanhe Nuclear Power Plant and Ningde Nuclear Power Plant , with five new nuclear power stations under construction and another two planned. CGN operates in wind energy and solar energy, as well as hydroelectricity. China Guangdong Nuclear Power Holding Co., Ltd. (CGNPC)

3162-474: The UK with a combined capacity of 73 megawatts from British energy company EDF Energy for a fee estimated to be in the region of £100 million. In November 2015, the company and its subsidiaries agreed to acquire 1Malaysia Development Berhad 's energy assets, worth around $ 2.3 billion. The transaction was part of the wider 1Malaysia Development Berhad scandal which resulted in billions of dollars being stolen from

3255-619: The United States Department of Justice charged CGN with stealing nuclear secrets from the United States. The Guardian reported: "According to the US Department of Justice, the FBI has discovered evidence that China General Nuclear Power (CGN) has been engaged in a conspiracy to steal US nuclear secrets stretching back almost two decades. Both CGN and one of the corporation’s senior advisers, Szuhsiung Ho, have been charged with conspiring to help

3348-556: The University of Massachusetts Lowell Radiation Laboratory . Sodium-bonded fuel consists of fuel that has liquid sodium in the gap between the fuel slug (or pellet) and the cladding. This fuel type is often used for sodium-cooled liquid metal fast reactors. It has been used in EBR-I, EBR-II, and the FFTF. The fuel slug may be metallic or ceramic. The sodium bonding is used to reduce the temperature of

3441-404: The liquid fluoride thorium reactor (LFTR), this fuel salt is also the coolant; in other designs, such as the stable salt reactor , the fuel salt is contained in fuel pins and the coolant is a separate, non-radioactive salt. There is a further category of molten salt-cooled reactors in which the fuel is not in molten salt form, but a molten salt is used for cooling. Molten salt fuels were used in

3534-483: The 3500 MWe gross delivered, around 180 MWe will be used by plant systems. Most of this is used to power the pumps that feed water into the steam generators. The pair of reactors can deliver 3320 MWe net for supply to the grid, making these the most powerful reactors in the world. Excavation work began on August 26, 2008. The first concrete for the first unit was poured in October 2009. Construction of each unit

3627-499: The 37-pin standard bundle. It has been designed specifically to increase fuel performance by utilizing two different pin diameters. Current CANDU designs do not need enriched uranium to achieve criticality (due to the lower neutron absorption in their heavy water moderator compared to light water), however, some newer concepts call for low enrichment to help reduce the size of the reactors. The Atucha nuclear power plant in Argentina,

3720-537: The ACPR1000 comprises 157 fuel assemblies (active length 14ft) and has a design life of 60 years. Other features include a core catcher and double containment as additional safety measures and ten major technical improvements over its predecessor the CPR-1000. It was the first Chinese reactor to have a domestically developed digital control system. In 2012, central planners in Beijing directed China General Nuclear (CGN) and

3813-462: The ACPR1000) but the design is considered to be standardised. Some 85% of its components will be made domestically. The Hualong One power output will be 1170 MWe gross, 1090 MWe net, with a 60-year design life, and would use a combination of passive and active safety systems with a double containment. It has a 177 assembly core design with an 18-month refuelling cycle. The power plant's utilisation rate

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3906-525: The Chinese government develop nuclear material in a manner that is in clear breach of US law." In August 2019, the U.S. Department of Commerce added CGN to its Entity List , barring U.S. companies from selling products to CGN. In its reasoning, the United States Department of Commerce explained that CGN attempted to acquire advanced U.S. nuclear technology to divert to military uses in China". The Chinese state-owned China Daily claimed that, "[T]he real aim

3999-521: The LFTR known as the Molten Salt Reactor Experiment, as well as other liquid core reactor experiments. The liquid fuel for the molten salt reactor was a mixture of lithium, beryllium, thorium and uranium fluorides: LiF-BeF 2 -ThF 4 -UF 4 (72-16-12-0.4 mol%). It had a peak operating temperature of 705 °C in the experiment, but could have operated at much higher temperatures since

4092-475: The TRISO particle more structural integrity, followed by a dense outer layer of PyC. TRISO particles are then encapsulated into cylindrical or spherical graphite pellets. TRISO fuel particles are designed not to crack due to the stresses from processes (such as differential thermal expansion or fission gas pressure) at temperatures up to 1600 °C, and therefore can contain the fuel in the worst of accident scenarios in

4185-581: The UK have received criticism from MPs as a potential threat to national security . In September 2021, the Nuclear Regulatory Commission suspended shipments of nuclear materials to CGN on national security grounds. CGN's first nuclear station uses reactors designed and built by the French National Company, Framatome , specifically the M310 plants at Daya Bay Plant . On the basis of

4278-523: The US and an additional 35 in other countries. In a fast-neutron reactor , the minor actinides produced by neutron capture of uranium and plutonium can be used as fuel. Metal actinide fuel is typically an alloy of zirconium, uranium, plutonium, and minor actinides . It can be made inherently safe as thermal expansion of the metal alloy will increase neutron leakage. Molten plutonium, alloyed with other metals to lower its melting point and encapsulated in tantalum ,

4371-773: The United Kingdom as part of the Dragon reactor project. The inclusion of the SiC as diffusion barrier was first suggested by D. T. Livey. The first nuclear reactor to use TRISO fuels was the Dragon reactor and the first powerplant was the THTR-300 . Currently, TRISO fuel compacts are being used in some experimental reactors, such as the HTR-10 in China and the high-temperature engineering test reactor in Japan. In

4464-452: The United States, spherical fuel elements utilizing a TRISO particle with a UO 2 and UC solid solution kernel are being used in the Xe-100 , and Kairos Power is developing a 140 MWE nuclear reactor that uses TRISO. In QUADRISO particles a burnable neutron poison ( europium oxide or erbium oxide or carbide ) layer surrounds the fuel kernel of ordinary TRISO particles to better manage

4557-644: The Western nuclear industry, and stated that " Coal fired power plants can emit and discharge more radioactivity than nuclear power plants." On June 16, 2021, the Ministry of Ecology and Environment released a conversation dialog with representatives from the NNSA. Five out of 60,000 fuel rods (0.01%) in reactor core 1 were estimated to be suffering from cladding defects. The ratio was well within design maximum fault rate of 0.25%. CGN stated there had been no release of radiation from

4650-401: The absence of oxygen in this fuel (during the course of irradiation, excess gas pressure can build from the formation of O 2 or other gases) as well as the ability to complement a ceramic coating (a ceramic-ceramic interface has structural and chemical advantages), uranium carbide could be the ideal fuel candidate for certain Generation IV reactors such as the gas-cooled fast reactor . While

4743-651: The advantage of a much higher heat conductivity than oxide fuels but cannot survive equally high temperatures. Metal fuels have a long history of use, stretching from the Clementine reactor in 1946 to many test and research reactors. Metal fuels have the potential for the highest fissile atom density. Metal fuels are normally alloyed, but some metal fuels have been made with pure uranium metal. Uranium alloys that have been used include uranium aluminum, uranium zirconium , uranium silicon, uranium molybdenum, uranium zirconium hydride (UZrH), and uranium zirconium carbonitride. Any of

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4836-515: The aforementioned fuels can be made with plutonium and other actinides as part of a closed nuclear fuel cycle. Metal fuels have been used in light-water reactors and liquid metal fast breeder reactors , such as Experimental Breeder Reactor II . TRIGA fuel is used in TRIGA (Training, Research, Isotopes, General Atomics ) reactors. The TRIGA reactor uses UZrH fuel, which has a prompt negative fuel temperature coefficient of reactivity , meaning that as

4929-424: The application of the new fuel-cladding material systems for various types of ATF materials. The aim of the research is to develop nuclear fuels that can tolerate loss of active cooling for a considerably longer period than the existing fuel designs and prevent or delay the release of radionuclides during an accident. This research is focused on reconsidering the design of fuel pellets and cladding, as well as

5022-420: The boiling point of the molten salt was in excess of 1400 °C. The aqueous homogeneous reactors (AHRs) use a solution of uranyl sulfate or other uranium salt in water. Historically, AHRs have all been small research reactors, not large power reactors. The dual fluid reactor (DFR) has a variant DFR/m which works with eutectic liquid metal alloys, e.g. U-Cr or U-Fe. Uranium dioxide (UO 2 ) powder

5115-562: The cause of the SCRAM to be a technician accidentally shorting a circuit during an onsite investigation of a slight under-voltage of a 10kV power supply. To prevent this accident from occurring in the future, all nuclear power plants were ordered to revise operating procedures to improve reliability and maintainability of similar power supplies. On April 11, 2021, the Chinese NNSA reported that another level 0 incident occurred on April 5, resulting in

5208-420: The chain-reaction. This mechanism compensates for the accumulation of undesirable neutron poisons which are an unavoidable part of the fission products, as well as normal fissile fuel "burn up" or depletion. In the generalized QUADRISO fuel concept the poison can eventually be mixed with the fuel kernel or the outer pyrocarbon. The QUADRISO concept was conceived at Argonne National Laboratory . RBMK reactor fuel

5301-440: The closest of which is at Yonaguni Island, did not measure any "abnormalities in data". Li Ning, a nuclear scientist based in the United States, criticized CNN as "making a mountain out of a molehill" , stating that it was unrealistic to expect "zero failure" in the fuel claddings at any nuclear reactor. Li also criticized the media for being "often unwilling to put risks into proper perspective" , which according to Li, killed

5394-532: The company among the first to build a nuclear station with generation III reactors . Operating stations: Under construction: Hongyanhe Nuclear Power Plant phase II, Ningde Nuclear Power Plant phase II, Planned: Lufeng Nuclear Power Plant , Xianning Nuclear Power Plant (entering early construction), Wuhu Nuclear Power Plant and Jiangsu's Second Nuclear Power Project Nuclear fuel#Common physical forms of nuclear fuel Nuclear fuel refers to any substance, typically fissile material, which

5487-510: The coolant and contaminating it. Besides the prevention of radioactive leaks this also serves to keep the coolant as non-corrosive as feasible and to prevent reactions between chemically aggressive fission products and the coolant. For example, the highly reactive alkali metal caesium which reacts strongly with water, producing hydrogen, and which is among the more common fission products. Pressurized water reactor (PWR) fuel consists of cylindrical rods put into bundles. A uranium oxide ceramic

5580-434: The established PUREX process is used commercially for about a third of all spent nuclear fuel (the rest being largely subject to a "once through fuel cycle"). All nitrogen-fluoride compounds are volatile or gaseous at room temperature and could be fractionally distilled from the other gaseous products (including recovered uranium hexafluoride ) to recover the initially used nitrogen. If the fuel could be processed in such

5673-491: The excess of reactivity. If the core is equipped both with TRISO and QUADRISO fuels, at beginning of life neutrons do not reach the fuel of the QUADRISO particles because they are stopped by the burnable poison. During reactor operation, neutron irradiation of the poison causes it to "burn up" or progressively transmute to non-poison isotopes, depleting this poison effect and leaving progressively more neutrons available for sustaining

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5766-407: The fact that the used fuel can be cracked, it is very insoluble in water, and is able to retain the vast majority of the actinides and fission products within the uranium dioxide crystal lattice . The radiation hazard from spent nuclear fuel declines as its radioactive components decay, but remains high for many years. For example 10 years after removal from a reactor, the surface dose rate for

5859-412: The failure modes which occur during normal use (and the manner in which the fuel will behave during an accident) can be studied. In addition information is gained which enables the users of fuel to assure themselves of its quality and it also assists in the development of new fuels. After major accidents the core (or what is left of it) is normally subject to PIE to find out what happened. One site where PIE

5952-478: The first reactor using the third-generation nuclear power technology EPR. First criticality was achieved at Taishan Unit 1 on June 6, 2018. On June 29, 2018, Taishan 1 was connected to the grid. It became the first EPR to enter commercial operation on December 13, 2018. On March 2, 2021, the Chinese NNSA reported that a "level 0" incident occurred on February 21, which triggered an automatic emergency shutdown (a SCRAM ) of Unit 1. Post-incident investigation revealed

6045-403: The fuel is similar to PWR fuel except that the bundles are "canned". That is, there is a thin tube surrounding each bundle. This is primarily done to prevent local density variations from affecting neutronics and thermal hydraulics of the reactor core. In modern BWR fuel bundles, there are either 91, 92, or 96 fuel rods per assembly depending on the manufacturer. A range between 368 assemblies for

6138-850: The fuel mixture for significantly extended periods, which increases fuel efficiency dramatically and incinerates the vast majority of its own waste as part of the normal operational characteristics. A downside to letting the Xe escape instead of allowing it to capture neutrons converting it to the basically stable and chemically inert Xe , is that it will quickly decay to the highly chemically reactive, long lived radioactive Cs , which behaves similar to other alkali metals and can be taken up by organisms in their metabolism. Molten salt fuels are mixtures of actinide salts (e.g. thorium/uranium fluoride/chloride) with other salts, used in liquid form above their typical melting points of several hundred degrees C. In some molten salt-fueled reactor designs, such as

6231-408: The fuel of choice for reactor designs that NASA produces. One advantage is that uranium nitride has a better thermal conductivity than UO 2 . Uranium nitride has a very high melting point. This fuel has the disadvantage that unless N was used (in place of the more common N ), a large amount of C would be generated from the nitrogen by the (n,p) reaction . As the nitrogen needed for such

6324-406: The fuel rods, standing between the coolant and the nuclear fuel. It is made of a corrosion -resistant material with low absorption cross section for thermal neutrons , usually Zircaloy or steel in modern constructions, or magnesium with small amount of aluminium and other metals for the now-obsolete Magnox reactors . Cladding prevents radioactive fission fragments from escaping the fuel into

6417-532: The fuel. Accident tolerant fuels (ATF) are a series of new nuclear fuel concepts, researched in order to improve fuel performance under accident conditions, such as loss-of-coolant accident (LOCA) or reaction-initiated accidents (RIA). These concerns became more prominent after the Fukushima Daiichi nuclear disaster in Japan, in particular regarding light-water reactor (LWR) fuels performance under accident conditions. Neutronics analyses were performed for

6510-468: The interactions between the two. Used nuclear fuel is a complex mixture of the fission products , uranium , plutonium , and the transplutonium metals . In fuel which has been used at high temperature in power reactors it is common for the fuel to be heterogeneous ; often the fuel will contain nanoparticles of platinum group metals such as palladium . Also the fuel may well have cracked, swollen, and been heated close to its melting point. Despite

6603-465: The introduction of additional absorbers. CerMet fuel consists of ceramic fuel particles (usually uranium oxide) embedded in a metal matrix. It is hypothesized that this type of fuel is what is used in United States Navy reactors. This fuel has high heat transport characteristics and can withstand a large amount of expansion. Plate-type fuel has fallen out of favor over the years. Plate-type fuel

6696-450: The level 0 incident previously reported on April 11, 2021. Further details provided by Framatome revealed that the issue was build-up of xenon and krypton inert fission gases in the primary circuit of Taishan 1, potentially from a leak in a fuel rod housing. The build-up was described as "known phenomenon" which is well covered in the plant's operating and safety procedures. On June 15, Japan reported that its radiation monitoring posts,

6789-420: The neutron cross section of carbon is low, during years of burnup, the predominantly C will undergo neutron capture to produce stable C as well as radioactive C . Unlike the C produced by using uranium nitrate, the C will make up only a small isotopic impurity in the overall carbon content and thus make the entirety of the carbon content unsuitable for non-nuclear uses but

6882-401: The news agency's request for comment. Later clarification revealed that the "boiler" was a deaerator vessel, which removes dissolved oxygen from water by heating it. In January 2018 commissioning was rescheduled, with commercial operation expected in late 2018 and 2019. This was the third delay in two years, involving a further deferral of 5 billion yuan (US$ 770 million). It was estimated that

6975-637: The other large nuclear builder and operator, CNNC to 'rationalise' their Generation III reactor design programs. This meant CGN's ACPR1000 and CNNC's ACP1000, both of which were based on the French Generation II M310 , were 'merged' into one standardised design - the Hualong One . After the merger, both companies retain their own supply chain and their versions of the Hualong One will differ slightly (units built by CGN will retain some features from

7068-465: The plant, and the small increase in the level of radioactivity was confined to the primary coolant circuit. After analysing the available data, EDF stated "This is not an emergency or an incident. It is a situation, that is covered by operating procedures, that is known and understood." However EDF said they were concerned about the French supplied fuel rods deteriorating further, and under regulations in France

7161-676: The plant’s investment cost would rise to between 22 and 23 yuan per watt from an originally budgeted 14 yuan. On April 9, 2018, the Official Letter of Approving the Initial Fuel Loading of the first unit of the Taishan Nuclear Power Plant was issued by the National Nuclear Safety Administration (NNSA). Taishan Unit 1 began fuel loading at 18:18 on April 10, marking the beginning of fuel loading of

7254-416: The plutonium in it usable for nuclear fuel but not for nuclear weapons. Reprocessing of spent commercial-reactor nuclear fuel has not been permitted in the United States due to nonproliferation considerations . All other reprocessing nations have long had nuclear weapons from military-focused research reactor fuels except for Japan. Normally, with the fuel being changed every three years or so, about half of

7347-486: The possibility of a runaway reactor meltdown, and providing an automatic load-following capability which is well suited to electricity generation and high-temperature industrial heat applications. In some liquid core designs, the fuel can be drained rapidly into a passively safe dump-tank. This advantage was conclusively demonstrated repeatedly as part of a weekly shutdown procedure during the highly successful Molten-Salt Reactor Experiment from 1965 to 1969. A liquid core

7440-422: The reactor would be shut down to investigate why the fuel rods had lost their sealings, and perform necessary maintenance. On 30 July 2021, the plant operator (CGNPC) reported that they have shutdown Taishan Unit 1 for maintenance after lengthy talks with relevant technicians. Engineers would find the cause of the damage and replace the affected fuel rods. On 16 August 2022, Taishan Unit 1 completed maintenance and

7533-410: The reactor. Stainless steel was used in the past, but most reactors now use a zirconium alloy which, in addition to being highly corrosion-resistant, has low neutron absorption. The tubes containing the fuel pellets are sealed: these tubes are called fuel rods . The finished fuel rods are grouped into fuel assemblies that are used to build up the core of a power reactor. Cladding is the outer layer of

7626-496: The smallest and 800 assemblies for the largest BWR in the U.S. form the reactor core. Each BWR fuel rod is backfilled with helium to a pressure of about 3 standard atmospheres (300 kPa). Canada deuterium uranium fuel (CANDU) fuel bundles are about 0.5 metres (20 in) long and 10 centimetres (4 in) in diameter. They consist of sintered (UO 2 ) pellets in zirconium alloy tubes, welded to zirconium alloy end plates. Each bundle weighs roughly 20 kilograms (44 lb), and

7719-587: The steel pressure vessels, and the two reinforced concrete designs operated at 24.8 and 27 bars (24.5 and 26.6 atm). Magnox alloy consists mainly of magnesium with small amounts of aluminium and other metals—used in cladding unenriched uranium metal fuel with a non-oxidising covering to contain fission products. This material has the advantage of a low neutron capture cross-section, but has two major disadvantages: Magnox fuel incorporated cooling fins to provide maximum heat transfer despite low operating temperatures, making it expensive to produce. While

7812-458: The temperature goes up. Corrosion of uranium dioxide in water is controlled by similar electrochemical processes to the galvanic corrosion of a metal surface. While exposed to the neutron flux during normal operation in the core environment, a small percentage of the U in the fuel absorbs excess neutrons and is transmuted into U . U rapidly decays into Np which in turn rapidly decays into Pu . The small percentage of Pu has

7905-560: The temperature of the core increases, the reactivity decreases—so it is highly unlikely for a meltdown to occur. Most cores that use this fuel are "high leakage" cores where the excess leaked neutrons can be utilized for research. That is, they can be used as a neutron source . TRIGA fuel was originally designed to use highly enriched uranium, however in 1978 the U.S. Department of Energy launched its Reduced Enrichment for Research Test Reactors program, which promoted reactor conversion to low-enriched uranium fuel. There are 35 TRIGA reactors in

7998-449: The top directly into the fuel bundle. The fuel bundles usually are enriched several percent in U. The uranium oxide is dried before inserting into the tubes to try to eliminate moisture in the ceramic fuel that can lead to corrosion and hydrogen embrittlement . The Zircaloy tubes are pressurized with helium to try to minimize pellet-cladding interaction which can lead to fuel rod failure over long periods. In boiling water reactors (BWR),

8091-399: The unexpected release of radioactive gas into the atmosphere. Post-accident investigation calculated the amount of radioactive release to contribute to 0.00044% of annual limit, well within safety parameters. On June 14, 2021, CNN reported that the Taishan Nuclear Power Plant had a suspected leak, based on a report by Framatome communicated to the United States on June 8. Said incident was

8184-407: The use of uranium metal rather than oxide made nuclear reprocessing more straightforward and therefore cheaper, the need to reprocess fuel a short time after removal from the reactor meant that the fission product hazard was severe. Expensive remote handling facilities were required to address this issue. Tristructural-isotropic (TRISO) fuel is a type of micro-particle fuel. A particle consists of

8277-442: Was connected to the grid on 15 August 2022. The Taishan Nuclear Power Plant Phase I consists of two reactors: both reactors are in commercial operation. Its Phase II consists of adding two additional reactors. China Guangdong Nuclear Power Group China General Nuclear Power Group (CGN) ( Chinese : 中国广核集团 ), formerly China Guangdong Nuclear Power Group ( 中国广东核电集团 ), is a Chinese state-owned energy corporation under

8370-498: Was established in September 1994 with a registered capital of RMB 10.2 billion with nuclear power as its core business. With CGNPC as its core enterprise, China Guangdong Nuclear Power Group (CGNPG) comprises more than twenty wholly owned or controlling subsidiaries. It is one of the two most significant companies in China's nuclear power industry and uranium mining (the other is China National Nuclear Corporation ). In April 2009,

8463-465: Was planned to take 46 months, significantly faster and cheaper than the first two EPRs in Finland and France. These plans proved elusive as start up was repeatedly delayed. In February 2017, after 88 months of construction, CGNPC announced that completion of the reactors would be delayed until the second half of 2017 and the first half of 2018. Areva (more specifically its subsidiary Framatome , which

8556-400: Was tested in two experimental reactors, LAMPRE I and LAMPRE II, at Los Alamos National Laboratory in the 1960s. LAMPRE experienced three separate fuel failures during operation. Ceramic fuels other than oxides have the advantage of high heat conductivities and melting points, but they are more prone to swelling than oxide fuels and are not understood as well. Uranium nitride is often

8649-548: Was used in Soviet -designed and built RBMK -type reactors. This is a low-enriched uranium oxide fuel. The fuel elements in an RBMK are 3 m long each, and two of these sit back-to-back on each fuel channel, pressure tube. Reprocessed uranium from Russian VVER reactor spent fuel is used to fabricate RBMK fuel. Following the Chernobyl accident, the enrichment of fuel was changed from 2.0% to 2.4%, to compensate for control rod modifications and

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