Heavy noble gas reactor core

Abstract

As one way of preparing for global cooling, we will provide a nuclear reactor that requires less investment capital, is based on the premise that population density will decrease due to population decline, and it is unknown when, where, and what scale an earthquake will occur, and of course does not require a final disposal site, and can convince the media and local residents by reducing the amount of spent nuclear fuel from light water reactors. [Solution] A nuclear reactor in which a large number of allowable alloy-containing nuclear fuel rod assemblies 1, each consisting of a large number of allowable alloy-containing nuclear fuel rods made of heavy noble gas coolant and allowable enrichment plutonium alloy, are arranged in a square lattice pattern in the core of an existing BWR.

Description

[Technical Field]

[0001] Fission-alloy nuclear fuel is an alloy of U-Pu-MA with Fission (a collective term for molybdenum, zirconium, palladium, platinum, etc.), which is difficult to remove but does not pose a major problem to reactor nuclear reactions, without completely removing fission products from spent nuclear fuel. Minor actinides MA include neptunium (Np), americium (Am), and curium (Cm). It also contains small amounts of Thorium (Th). In this invention, the spent oxide nuclear fuel from a light water reactor that contains fissium, U-Pu-MA, and Th is left intact, and the metallized nuclear fuel that has been devoid of volatiles and light-mass fissions is referred to as light water reactor fissium alloy nuclear fuel. The fuel rod assemblies of light water reactors consist of uranium oxide (UO2) and mixed oxides (MOX) made from uranium containing plutonium. [Background technology]

[0002] A local government mayor is demanding the decommissioning of a boiling water reactor. Refusing would cause a fuss, and they'd see through my weakness and make all sorts of demands. Decommissioning all boiling water reactors would take a century. Therefore, reusing at least some of the boiling water reactors is a viable option. Spent nuclear fuel from boiling water reactors is accumulating. This can be considered both accumulating waste and accumulating energy. As the future population decline has become clear, it seems that energy supplies can be met with renewable energy and imported fossil fuels. Since PWRs have been restarted, those involved in nuclear power have a good reputation. If subsidies are provided around PWRs, residents will continue to live there. Based on the premise that population density is low due to population decline, and that it is unknown when, where, and what magnitude of earthquake will occur, it goes without saying that a final disposal site will not be necessary, and a nuclear reactor will be built that can persuade the media and local residents to reduce the amount of spent nuclear fuel from light water reactors. Furthermore, just as we would not call it an apartment building without a toilet, there would be little opposition to reducing the radioactive waste (solid radioactive fission products containing almost no Th, U, Pu, or MA) discharged from the nuclear power plant. If the reactor is decommissioned as is, everything inside the containment vessel, including the nuclear fuel, will be considered garbage. The next issue to be addressed is the final disposal of this garbage. In particular, securing energy is a major concern. Renewable energy sources are too vulnerable to violence such as war and terrorism. Nuclear power plants are anchored in bedrock that is designed to remain stationary, making them resistant to human violence. Recently, plates have been moving slowly, causing earthquakes even in relatively inland areas, accompanied by the release of water. What is frightening now is not a nuclear attack from a nearby country, but the collapse of the country's system. It is unclear how people will act. Measures against illegal immigration and refugees are a major concern. Europe and the United States are plagued by immigrants and illegal immigrants. Even in the United States, it is not easy to prevent people from entering via the Bering Sea or the Caribbean Sea. Nuclear power plants may be robust, but the safety of their transmission and distribution lines is uncertain. Cities are located very far from nuclear power plants. DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0003] Today's electric power companies make profits whether they have nuclear power or not. If that were the case, the presidents, executives, employees, shareholders, and urban taxpayers would likely choose not to have nuclear power. They would be able to focus on selling electricity without any worries and still secure profits. In a few decades, there is a good chance that there will be no residents living near nuclear power plants. Once that happens, it would be fine to restart nuclear power plants. Ultimately, the natural course of action in a capitalist society would be to force the electric power company into bankruptcy (capitalism exists because of the bankruptcy system) and then rebuild it with new assets. On the Sea of ​​Japan side, considering the hot fingers, lava may erupt from places where there don't appear to be any mountains. Hot water may also erupt. In this situation, the challenge is how to convince groups that want the BWRs to be restarted. Technology depends on the social situation at the time. An era has arrived in which politicians, business people, and the public and private sectors all avoid responsibility. Politicians who are part of the populace become popular. Marriage and child-rearing are avoided, and the birth rate continues to decline. Energy demand continues to decline. Restarting nuclear power plants would technically be no problem. However, it would be difficult to gain the support of all local residents. It would also be difficult to gain the support of national newspapers. It would be impossible to gain the support of all Japanese citizens. In particular, it would be difficult to build new conventional nuclear reactors in a Diet dominated by mob politicians. The democratic dictator Pericles (of a noble family) was defeated by mob politicians. In Japan, too, despite calling for the transfer of politics from the central government to the local governments, he has now started threatening Tokyo to hand over goods, people, and money to the local governments. In local elections, people who promised to attract companies and people have been elected. Previously, nuclear power plants could be restarted with the power of absolute authority, but there is no absolute authority that can withstand the test of time for at least 20 years. The idea that the matter could be resolved by levying additional taxes and replacing the leaders of violating factions has been expanded to the destruction of factions (where there was no faction leader, several violators were punished. This was recognized as a party). This is the collapse of authority. It is a victory for mob politicians. If the head of a democratic country wants to get his or her opinion across, he or she has no choice but to bestow bribes, positions, and privileges, as was the case with Tanaka Kakuei. In a dictatorship, he or she would have to kill the leader, as was the case with Stalin and Mao Zedong. The citizens who support each party, guided by each party, work together with the media to support their favorite politicians. Most of us ordinary people spend our days lazily, not paying any attention to political parties or affiliations, and not even reading the newspapers. It is the role of politicians to ensure that we ordinary people can spend our days lazily. Threats from neighboring countries are dealt with by politicians. It is particularly unusual that the Rokkasho-mura Reprocessing Plant has continued to be delayed for so long due to problems. There appears to be some kind of external pressure. If this is the case, we must consider ways to use nuclear fuel produced by reprocessing that does not result in complete separation of uranium and plutonium, and that is not oxides. What kind of nuclear reactors would be allowed to operate under the above social conditions? [Means for solving the problem]

[0004] Means 1 is a heavy noble gas cooled reactor. The reactor utilizes a boiling water reactor core, which is comprised of a pressure vessel (10) filled with coolant, and nuclear fuel rod assemblies arranged in a square lattice adjacent to a number of cross-shaped control rods (22) arranged in a square lattice. The coolant is a heavy noble gas coolant instead of water. The reactor core, which contains a large number of nuclear fuel rod assemblies, is divided into three regions: the center, middle, and outer periphery of the core. The outer periphery of the core is provided with an array of moderator-mixed UO2-based fissium alloy-embedded nuclear fuel rod assemblies (3), each of which is composed of a large number of moderator-mixed UO2-based fissium alloy-embedded nuclear fuel rods (301) arranged in a square lattice pattern. The moderator-mixed UO2-based fissium alloy-embedded nuclear fuel rods (301) are made by mixing solid moderator particles such as depleted boron compound powder or silicon carbide powder with a fissium alloy produced from uranium oxide spent nuclear fuel. In the middle of the core, a MOX-based fissium alloy-containing nuclear fuel rod assembly (2) is arranged, which is made up of a large number of MOX-based fissium alloy-containing nuclear fuel rods (201) arranged in a square lattice pattern. The MOX-based fissium alloy-containing nuclear fuel rod assembly (2) is made up of a fissium alloy produced from spent MOX nuclear fuel. In the center of the core, a number of allowable alloy-containing nuclear fuel rod assemblies (1) are arranged in a square lattice pattern, each of which is made of an allowable alloy-containing nuclear fuel rod (101) made of an allowable enrichment uranium metal or an allowable enrichment plutonium alloy. The core of a heavy noble gas coolant reactor is made up of a nuclear fuel rod assembly as described above and a heavy noble gas. Prior examples of the present invention include Patent Documents 1, 2 and 3. [Patent Document 1] Patent application 2023-131719 [Patent Document 2] Patent application 2023-189696 [Patent Document 3] Patent application 2023-148573

[0005] If the decontamination factor is lowered, phisium alloy nuclear fuel can be extracted. It would be desirable to extract Pu from this phisium alloy nuclear fuel by reprocessing, but nuclear weapon states such as the United States, China, North Korea, and Russia oppose and obstruct this. UO2-based fissium alloy nuclear fuel manufactured from spent nuclear fuel from light water reactors has a U235 enrichment of 1 wt% or more, which is the allowable enrichment level of uranium metal nuclear fuel (the enrichment level of U235 at the time of shipping of the nuclear fuel rod assembly is 5 wt% for BWRs and 10 wt% for PWRs). The plutonium enrichment is 1 wt% or less. Some spent nuclear fuel is unused, unburned new nuclear fuel. MOX-based fissium alloy nuclear fuel manufactured from spent nuclear fuel from light water reactors has a U235 enrichment of approximately zero percent and a plutonium enrichment of approximately 100%. The plutonium content of the fuel rod assembly at the time of shipment is 3 wt% or more for BWRs and 7-10 wt% for PWRs. Some spent fuel is unused, unburned new fuel. It is difficult to achieve criticality with UO2-based fissium alloy nuclear fuel when cooled with heavy noble gases. Therefore, a solid moderator is mixed with the fuel to create a moderator-mixed UO2-based fissium alloy nuclear fuel, which allows it to approach criticality. MOX-based fissium alloy nuclear fuel is difficult to make critical with heavy noble gas cooling because it has a low plutonium enrichment. Plutonium alloy nuclear fuel with an allowable enrichment becomes critical when cooled by heavy noble gases. Plutonium contains trace amounts of uranium and MA, so it is called plutonium alloy. The faster the neutrons generated in the reactor core, the more likely they are to leak out of the core. Therefore, if a moderator-mixed UO2-based Fisium alloy-containing nuclear fuel rod assembly (3) consisting of a large number of moderator-mixed UO2-based Fisium alloy-containing nuclear fuel rods (301) arranged in a square lattice around the outer periphery of the core, the fast neutrons coming from the center of the core will be slowed down by the moderator and converted into thermal neutrons. Both U235 and plutonium undergo violent nuclear fission due to thermal neutrons. The fast neutrons generated in the nuclear fuel rod assembly (3) will be slowed down by the moderator. Therefore, the rate at which they leak outside the core is low. If an allowable alloy-containing nuclear fuel rod assembly (1) consisting of a large number of allowable alloy-containing nuclear fuel rods (101) containing allowable enrichment plutonium alloy nuclear fuel as cylindrical nuclear fuel pieces (40) arranged in a square lattice is laid in the center of the core, excess fast neutrons will leak into the middle of the core. The MOX-based fissium alloy-embedded nuclear fuel rod assembly (2) is laid in the middle of the reactor core and is composed of a large number of MOX-based fissium alloy-embedded nuclear fuel rods (201) arranged in a square lattice pattern, each rod containing MOX spent nuclear fuel as cylindrical nuclear fuel pieces (40). The assembly absorbs the excess fast neutrons and maintains nuclear fission. Accumulated LWR spent nuclear fuel can be effectively burned. The spent nuclear fuel generated in this reactor is metallic and therefore easy to reprocess. In addition, because it is fissium alloy nuclear fuel, it is also easy to produce reprocessed fuel for reloading. [Effects of the Invention]

[0006] Waste is a prerequisite for increasing GDP. Waste is necessary to keep the home environment clean. Electric washing machines and other home appliances are essential for keeping it clean. Electricity, which is a surface energy source, is said to be good for the global environment. Windmills and solar cells are produced using fossil fuels, which are cheap energy. Carbon dioxide is invisible, so it is discarded into the atmosphere. On the other hand, the nuclear reactor of this invention uses spent nuclear fuel, which is accumulated waste, as its energy source, resulting in less pollution. The dimensions of the core and fuel rod assembly are the same as those of existing boiling water reactors and fuel rod assemblies from BWR5 onwards. However, the length of the fuel rod portion of the fuel rods is approximately half. The density of metallic uranium is approximately twice that of uranium oxide. The length of the spring (45) is increased. If the crane can withstand twice the weight, the length of the fuel rod portion of the fuel rods can be made the same as the dimensions of existing fuel rod assemblies from BWR5 onwards. By reducing the thickness of the nuclear fuel rods, the dimensions can be made the same as those of existing nuclear fuel rod assemblies from WR5 onwards. BEST MODE FOR CARRYING OUT THE INVENTION

[0007] It has been possible to provide a nuclear reactor that can nuclearly burn up accumulated spent nuclear fuel and use the heat generated in the process of nuclear burnup to generate electricity. Example 1

[0008] Example 1 is a heavy noble gas cooled reactor. Figure 1 shows an overview of a heavy noble gas cooled reactor. Most of the equipment, such as the pressure vessel (10), will be used as is from existing nuclear power plants. FIG. 1 shows a schematic view of a nuclear fuel rod assembly of the present invention loaded into a pressure vessel (10) of a conventional boiling water reactor (Non-Patent Document 1). After the turbine has completed its work, the low-temperature, low-pressure heavy noble gas passes through the coolant supply pipe (17) and enters the lower core plenum (8) through the coolant inlet pipe (25) laid in the outer shroud coolant space (16) between the pressure vessel (10) wall and the shroud (18). In addition to the coolant supply pipe (17), the low-temperature, low-pressure heavy noble gas can also enter the lower core plenum (8) through the coolant inlet pipe (25) from the emergency core cooling system (ECCS) pipe. The lower core plenum (8) is surrounded by the bottom of the pressure vessel (10) and the core support plate (9) and is filled with high-pressure heavy noble gas. The core support plate (9) supports the nuclear fuel rod assembly (1) containing the allowable alloy of the present invention, the nuclear fuel rod assembly (2) containing the MOX-based Fisium alloy, and the nuclear fuel rod assembly (3) containing the UO2-based Fisium alloy mixed with moderator. The low-temperature heavy noble gas that enters the lower core plenum (8) enters the lower ends of the nuclear fuel rod assemblies (nuclear fuel rod assemblies (1) containing allowable alloys, nuclear fuel rod assemblies (2) containing MOX-based fissium alloys, and nuclear fuel rod assemblies (3) containing moderator-mixed UO2-based fissium alloys), absorbs heat from the nuclear fuel rods of the nuclear fuel rod assemblies (nuclear fuel rod assemblies (1) containing allowable alloys, nuclear fuel rod assemblies (2) containing MOX-based fissium alloys, and nuclear fuel rod assemblies (3) containing moderator-mixed UO2-based fissium alloys), and flows upward. The low-temperature heavy noble gas that flows through the gaps between the nuclear fuel rod assemblies flows upward through the leaking coolant passage (20). The high-temperature heavy rare gas flowing out from the top of the nuclear fuel rod assembly (nuclear fuel rod assembly containing an allowable alloy (1), nuclear fuel rod assembly containing a MOX-based Fisium alloy (2), nuclear fuel rod assembly containing a moderator-mixed UO2-based Fisium alloy (3)) and the medium-temperature heavy rare gas flowing out from the top of the leaked coolant passage (20) are mixed in the mixing area (19), enter the coolant dome (11), and exit to the gas turbine through the high-temperature heavy rare gas pipe (14). Control of reactor power is achieved by means of cross-shaped control rods (22) which are moved up and down by control rod drives (23). Figure 2 is a perspective view of an allowable alloy-embedded nuclear fuel rod assembly (1) containing nuclear fuel material and a cross-shaped control rod (22) (Non-Patent Document 2). The allowable alloy-embedded nuclear fuel rod assembly (1) consists of a large number of cylindrical allowable alloy-embedded nuclear fuel rods (101) containing nuclear fuel material arranged in a square lattice (rarely a triangular lattice), with their lower ends inserted into a lower fuel tie plate (40), and the bundle of embedded nuclear fuel rods (101) is covered on all four sides by a channel box (35) made of zirconium alloy or stainless steel plates molded into a square frame. The nuclear fuel rod assembly (1) containing the allowable alloy is supported by the fuel rod assembly support bracket (50). The space between the contained nuclear fuel rods (101) is the main coolant passage (36), through which heavy noble gas, which is used to extract heat from the reactor, flows upward, absorbing heat from the nuclear fuel rods. Heavy rare gas flows through the leak coolant passage (20) between adjacent fuel rod assemblies (1) containing allowable alloys. The cross-shaped control rods (22) can move up and down between the channel boxes (35). The cross-shaped control rods (22) are made of hafnium thin plates, a material with strong neutron absorption properties that controls the reactor power. The cross-shaped control rods (22) move up and down by the control rod drive mechanisms (23) housed in the control rod guide tubes (26). The heavy noble gas in the lower core plenum (8) enters the fuel rod assembly support bracket (50) through the coolant inlet (99) opened in the control rod guide tube (26), and then flows into the lower end of the nuclear fuel rod assembly (1) containing the allowable alloy. The fuel rod assembly support bracket (50) is supported by the control rod guide tubes (26) and the core support plate (9). The arrows in the figure indicate the main flow direction of the coolant. Figure 3 is an overview of a nuclear fuel rod (101) containing an allowable alloy. It consists of a zirconium alloy or stainless steel cladding tube (41) that is a cylindrical sheath with a diameter of approximately 12 mm and a length of 2 to 4 m, upper end plugs (42) and lower end plugs (43) that hermetically close the upper and lower open ends of the cladding tube (41), a number of cylindrical nuclear fuel pieces (40) that are loaded into the cladding tube (41), and a spring (45). The cylindrical nuclear fuel pieces (40), each with a diameter of approximately 8 mm and a length of approximately 40 mm, are made of uranium metal or plutonium alloy with an allowable enrichment level. The allowable enrichment level of uranium metal is enriched uranium metal with a U235 enrichment level of approximately 5 wt% from the viewpoint of criticality safety. The allowable enrichment plutonium alloy is an alloy of depleted uranium or natural uranium containing plutonium (Pu) enrichment of about 10 wt% from the viewpoint of criticality safety. In the case of the MOX-based fissium alloy-embedded nuclear fuel rod (201), the cylindrical nuclear fuel piece (40) is made of a fissium alloy produced from MOX spent nuclear fuel. In the case of the nuclear fuel rod (301) containing a moderator-mixed UO2-based fissium alloy, the cylindrical nuclear fuel piece (40) is made by mixing depleted boron compound powder or silicon carbide powder solid moderator particles with a fissium alloy produced from uranium oxide spent nuclear fuel. Figure 4 is a plan view of a core using a boiling water reactor, consisting of a nuclear fuel rod assembly containing an allowable alloy (1), a nuclear fuel rod assembly containing a MOX-based fissium alloy (2), a nuclear fuel rod assembly containing a moderator-mixed UO2-based fissium alloy (3), and a cross-shaped control rod (22). Heavy rare gas flows from the bottom into the leakage coolant passage (20) between the adjacent fuel rod assembly (1) containing an allowable alloy, the fuel rod assembly (2) containing a MOX-based Fisium alloy, and the fuel rod assembly (3) containing a moderator-mixed UO2-based Fisium alloy. The cross-shaped control rod (22) can move up and down in the leakage coolant passage (20). The reactor core, surrounded by a cylindrical stainless steel shroud (18), is filled with heavy noble gas and consists of nuclear fuel rod assemblies (1) containing allowable alloys, nuclear fuel rod assemblies (2) containing MOX-based fissium alloys, nuclear fuel rod assemblies (3) containing UO2-based fissium alloys as a moderator, and cross-shaped control rods (22) containing neutron absorbers. The leaking coolant passages (20) are formed between adjacent nuclear fuel rod assemblies (1) containing allowable alloys, nuclear fuel rod assemblies (2) containing MOX-based fissium alloys, and nuclear fuel rod assemblies (3) containing UO2-based fissium alloys as a moderator, through which heavy noble gas flows. The outside of the shroud 18 is covered with the pressure vessel 10. An extra-shroud coolant space 16 between the pressure vessel 10 and the shroud 18 is filled with heavy noble gas. When the reactor is shut down, all of the cross-shaped control rods (22) are inserted into the core. When the reactor is operating, most of the cross-shaped control rods (22) are withdrawn from the core below, and only a few central cross-shaped control rods (22) are inserted into the core. [Non-Patent Document 1] : Corona Publishing, author Toko, "Atomic Power", pages 117 and 120. [Non-patent document 2] : Denryoku Shinposha, 1969, Agency for Natural Resources and Energy "Nuclear Power Generation Handbook" [Industrial Applicability]

[0009] They want to attract businesses, so they use the bait of inviting or accepting nuclear power plants. Even if you go along with that, they suddenly put their opposition to nuclear power at the forefront. This should not be included in the ad hoc appeals of politicians and residents of marginalized villages. Houses will be built in tsunami evacuation zones, but residents will never return to inconvenient land. Attracting businesses is for the benefit of local construction companies. City dwellers dislike the taxes required for this. City dwellers have abandoned the ruling party. They don't do anything good like hometown tax donations. Nuclear reactor accidents are a problem for the government and power companies, and have nothing to do with city dwellers. They don't need to oppose the location and refuse to supply electricity. This can be met with city gas power generation and perovskite solar cells. There are few city residents, and they commute from neighboring prefectures. City dwellers have their own stubbornness and desires. Immediately after the war, farmers anticipated food shortages and took advantage of their neighbors. Even if you nod along to them as a courtesy, they don't notice, or they pretend not to notice, wanting to think they're clever and taking advantage of them. Don't be so soft-spoken that it might lead to misunderstandings. Entrusting the future to Japan poses a risk to businesses. It would be safer to generate electricity overseas and export rechargeable batteries, ammonia, and hydrogen to Japan. However, from the end of the Edo period through the Meiji era, hidden geniuses and talented individuals began to emerge. Selfless politicians and philanthropists supported them. It is also true that some 20-somethings became elder retainers. Neither the Liberal Democratic Party nor the Constitutional Democratic Party of Japan has absolute authority now, so the only way they can help local areas is by hiring local government employees to combat unemployment. Building new nuclear reactors is probably out of the question. Since the reactor of the present invention generates electricity while reducing the accumulated spent nuclear fuel from conventional light water reactors, it would be fine if the reactor of the present invention could be put into full operation once the current light water reactors reach their limit. We will continue to conduct detailed research to give people hope that spent nuclear fuel can be reduced. If a nuclear power plant accident occurs, compensation of 1 trillion yen will be required, so it is an honor for a company president to be recognized as being worth 1 trillion yen. Presidents need to take out separate insurance. Alternatively, they need to have personal plans that assume bankruptcy. If a corporation is recognized as having to pay 1 trillion yen in compensation, it will immediately go bankrupt. Companies that own nuclear power plants at the request of various parties should establish independent corporations for each nuclear power plant in preparation for compensation of more than 1 trillion yen. Bankruptcies are what make a capitalist society possible. The nuclear power plant of this invention will be an independent corporation for each unit. Construction will begin if we receive a plea bargain with the Ministry of the Environment's Nuclear Regulation Authority and are granted permission to go bankrupt for 500 billion yen. Major electric power companies have changed significantly since the old days. They now have the ability to import fossil fuels and other resources. They can purchase abandoned land they have taken over for a fee, perovskite solar cells, and solar power generation, which has become low-cost thanks to various subsidies. Electricity supplies from Tokyo Gas, Osaka Gas, and other sources are expected. Iodine, one of the materials used in perovskite solar cells, is a room-temperature solid that sublimes at 118°C. It is a by-product of natural gas production in Chiba Prefecture. Because it is related to the plate boundary, strategic storage in onshore tanks outside of Chiba Prefecture is necessary. For example, once the Fukushima contaminated water tanks, which the media made such a fuss about but are now disinterested in, are emptied, iodine can be stored in these tanks. They can feign indifference toward self-proclaimed powerful figures and saints. They are also prepared to accept that it is unavoidable if the government allows foreign capital to flow in. Even if a nuclear power plant is hit by a natural disaster, the money that flows into the local area from decommissioning and repair work will be important for the weakened local economy. It is unclear why the government, which controls TEPCO and has provided over 100 billion yen in support for Tsuruga No. 2, is so determined to restart the plant. The decision to restart Tsuruga No. 2 will likely be decided by a tug-of-war between urban residents nationwide, residents living near the reactor, and shareholders of the reactor. The tug-of-war between other interest groups is a matter for them alone. We can no longer rely on authority. Shareholders and local residents are silent. Local residents would likely agree to decommissioning for less than 100 billion yen. Even if an earthquake, tsunami, or volcanic disaster leaves debris on the site, it won't be a problem. It can simply be covered with concrete. Nuclear power is no longer a national policy. It's merely one of many energy sources. In Japan, natural disasters lead to the creation of real demand. Tsuruga No. 2 Nuclear Power Plant has been deemed to have "failed," but the plant is likely to appeal. The future is uncertain. The Ministry of the Environment's Nuclear Regulation Authority is too involved with the private sector. They should honestly declare that they "cannot take responsibility for issuing the certificate of approval and lack confidence," and leave the decision of whether or not to operate the plant to the Tsuruga Unit 2 power plant. The only option is to change the review committee members and the chairman with each appeal. Bureaucrats should not do anything that would lead to them being held accountable, and politicians and private companies should not hold bureaucrats accountable. Bureaucrats are engineers when it comes to legal procedures. Neutrality is important for bureaucrats. Bureaucrats have a strong influence over the vulnerable. If bureaucratic work is delayed, the payment of pensions and welfare benefits will be delayed. However, recently, the process has been simplified with the introduction of My Number, which allows for automatic delivery. With government guidance, major banks could probably take over the work. At that time, once the ideal reactor (PWR or BWR) was created, general contractors and other organizations took the lead and the reactors became larger. This did not change even if the surrounding environment changed. Therefore, the traditional LWR would depend on the wishes of general contractors, heavy industries, and politicians. Now that the situation has changed, it is exciting to see bureaucrats using funds to conduct detailed research on various nuclear reactors from a new perspective. Since a new nuclear reactor is to be located and constructed, a disposal site, means, and method for radioactive waste, which is a nuisance to residents and the general public, must also be presented. Currently, no better proposal has been made than this one. Progress on Yucca Mountain does not seem to be going well. If a private company is investing in the new sodium-cooled fast breeder reactor in the United States, that is up to that company. However, it is possible to reassure the United States and prevent them from becoming suspicious by stating that the nuclear fuel for Japan's fast breeder reactors is imported from the United States. If it is certain that the population will continue to decline, there will be no need for a final disposal site. However, this depends on the period and time frame under consideration. [Brief explanation of the drawings]

[0010] [Figure 1] Schematic diagram of a heavy noble gas-cooled reactor. [Figure 2] 1 is a perspective view of a nuclear fuel rod assembly (1) containing an allowable alloy containing nuclear fuel material and a cruciform control rod (22). [Figure 3] Schematic diagram of a nuclear fuel rod (101) containing an acceptable alloy. [Figure 4]A plan view of a core consisting of a nuclear fuel rod assembly containing an allowable alloy (1), a nuclear fuel rod assembly containing a MOX-based Fisium alloy (2), a nuclear fuel rod assembly containing a UO2-based Fisium alloy mixed with a moderator (3), and a cruciform control rod (22) using a boiling water reactor. [Explanation of symbols]

[0011] 1 is a nuclear fuel rod assembly containing an allowable alloy 2 is a nuclear fuel rod assembly containing MOX-based phisium alloy 3 is a nuclear fuel rod assembly containing a moderator mixed UO2-based phisium alloy 8 is the lower core plenum 9 is the core support plate 10 is a conventional pressure vessel 11 is the coolant dome 14 is a high-temperature heavy rare gas pipe 16 is the outer shroud coolant space 17 is the coolant supply pipe 18 is Shroud 19 is the mixed region 20 is the leaking coolant passage 22 is a cross-shaped control rod 23 is the control rod drive mechanism 25 is the cooling inlet pipe 26 is the control rod guide tube 35 is a channel box 36 is the main coolant passage 37 is the lower fuel tie plate 40 is a cylindrical nuclear fuel fragment 41 is cladding tube 42 is the upper end plug 43 is the bottom end plug 45 is spring 50 is a nuclear fuel rod assembly support bracket 99 is the coolant inlet 101 is a nuclear fuel rod containing an allowable alloy 201 is a MOX-based phisium alloy-embedded nuclear fuel rod 301 is a nuclear fuel rod containing a moderator mixed UO2-based phisium alloy

Claims

[Claim 1] In the present invention, a boiling water reactor core is used, which is made up of a pressure vessel (10) filled with a coolant, and nuclear fuel rod assemblies arranged in a square lattice adjacent to a number of cross-shaped control rods (22) arranged in a square lattice, The water coolant is replaced with a heavy rare gas coolant, The reactor core, which contains a large number of nuclear fuel rod assemblies, is divided into three regions: the center, middle, and outer periphery of the core. The reactor core is provided with a plurality of UO2-based fissium alloy-embedded nuclear fuel rod assemblies (3) arranged in a square lattice pattern on the outer periphery of the core, each of which is a nuclear fuel rod (301) containing a moderator-embedded UO2-based fissium alloy, the nuclear fuel rod being made by mixing solid moderator particles and a fissium alloy produced from uranium oxide spent nuclear fuel. In the middle of the core, a MOX-based fissium alloy-containing nuclear fuel rod assembly (2) is arranged, which is composed of a large number of MOX-based fissium alloy-containing nuclear fuel rods (201) made of a fissium alloy produced from MOX spent nuclear fuel, arranged in a square lattice pattern; In the center of the reactor core, a large number of allowable alloy-containing nuclear fuel rod assemblies (1) are arranged in a square lattice pattern, each of which is made of an allowable enrichment uranium metal or an allowable enrichment plutonium alloy. A core of a heavy noble gas coolant nuclear reactor, comprising the above-mentioned nuclear fuel rod assembly and a heavy noble gas.

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