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🌏 | Kansai Electric Power's three nuclear power plants for more than 40 years, Governor of Fukui agrees to restart


Governor of Fukui Prefecture agrees to restart three nuclear power plants of Kansai Electric Power Co., Inc. for more than 40 years

If you write the contents roughly
The new standard established after the accident stipulates that the operating period of the reactor is 40 years, but if approved by the Nuclear Regulation Authority, it is allowed to be extended up to 1 years only once.

[Tokyo XNUMXth Reuters] – Governor Tatsuji Sugimoto of Fukui Prefecture announced on the XNUMXth that a nuclear power plant has been in operation for more than XNUMX years ... → Continue reading


Wikipedia related words

If there is no explanation, there is no corresponding item on Wikipedia.


Nuclear engineeringInReactor(Genshiro,British: nuclear reactor) Means a device in which nuclear fuel etc. are arranged so that a controlled fission chain reaction can be maintained.[2].


235U and 239Pu etc.Fissile materialIs generated by absorbing neutronsFission reactionIs a new neutron, i.e.Prompt neutron(Prompt neutron) andDelayed neutrons(Delayed neutron) is released.

These neutrons have an average energy of about 2 MeV, but if fissile material is still present in the medium, the neutrons will also undergo a fission reaction with them and emit new neutrons.この過程は次々と繰り返され、いわゆる連鎖反応、すなわちThis process is repeated one after another, so-called chain reaction, that is,Fission chain reaction(Fission chain reaction) occurs.

What makes this fission chain reaction take place in an extremely short time and releases enormous energy instantlyAtomic bombA device for safely extracting fission energy, etc. by generating a controlled nuclear fission chain reaction.ReactorCalled (nuclear reactor)[3].

It should be noted that nuclear energy is extracted by maintaining a controlled fusion reaction.Nuclear fusion reactor[4] See below for more information.

In addition, natural fission reactors may be created under certain conditions similar to artificial reactors.知られている唯一の天然原子炉はThe only known natural nuclear reactorガボンOklo, Haut-Ogoou, Republic[5] There is an Oklo Mine reactor that was formed 20 billion years ago.

Reactor classification

Classification of neutrons by major energy region

Reactor types can be classified in terms of how much kinetic energy neutrons are used to maintain the critical state.

Thermal neutron reactor(Thermal neutron reactor)
Fast neutrons by using moderatorThermal neutronsReactor designed to slow down to and maintain the fission chain reaction with its thermal neutrons[6][7].
Medium-speed neutron reactor (intermediate reactor)
A nuclear reactor designed to maintain the fission chain reaction mainly by medium-speed neutrons.減速材はあまり使用しないModerator is not used much[8].
Fast neutron reactor(Fast neutron reactor)
Fast neutronReactor designed to maintain fission chain reaction[9]..Moderators are not used.

ModeratorSubdivision by

Light water moderated reactor,Light water reactor)
Ordinary water (Light water) As a moderator[10].Boiling water reactor (BWR),Pressurized water reactor Two methods (PWR) are mainly used.
Heavy water moderated reactor,Heavy water reactor)
heavy waterReactor used as moderator[11].
Graphite moderated reactor,Graphite furnace)
graphiteReactor used as moderator[12].

Classification by fuel type

Natural-uranium fuel reactor
A nuclear reactor that uses natural uranium as fuel.Heavy water or graphite can be used as the moderator.
Enriched uranium fuel reactor
235U-enriched uranium-fueled nuclear reactor[13].
Plutonium fuel reactor
A plutonium-fueled nuclear reactor.
Thorium series fuel reactor
Made from thorium with thorium as the parent substance 233A nuclear reactor that uses U as fuel.

Subclassification by fuel type

Metallic fuel reactor
A nuclear reactor that uses uranium as it is as a metal or an alloy of other metals.Examples include uranium-molybdenum alloys.
Ceramic fuel reactor
Uranium and the like are used as oxides and carbides.It is mainly used as fuel for power furnaces.

CoolantClassification by type

Light water cooled reactor
Ordinary water (Light water) As a coolant[14].
Heavy water cooled reactor
heavy waterA nuclear reactor that uses as a coolant.
Gas cooled reactor
AirheliumOr carbon dioxide (carbon dioxide) As a coolant[15].
Liquid metal cooled reactor(Liquid metal cooled reactor)
mercury,sodium,lead,lead·BismuthReactors that use liquid metals such as alloys as coolant[16][17].

Classification by output

(English edition)

Reactor that is modularized for each containment vessel and has an output of 30 kW or less[18][19].

Classification by purpose of use

Power reactor (power reactor)
A nuclear reactor for obtaining power for power generation or propulsion of ships.
Nuclear plane,Nuclear carrier,Nuclear submarine,Nuclear ship,Nuclear locomotiveUsed for etc.
Material test reactor
A nuclear reactor that conducts irradiation experiments of materials and fuels.Plutonium production furnace, etc.
Multi-purpose reactor
A nuclear reactor used for multiple purposes such as power generation, seawater desalination, and process heat.
Bio-medical reactor
Biology, medicine, or medicalisotopeUsed in the production of.

Classification according to the development stage of the reactor under development

Research reactor (research reactor) or experimental reactor (experimental reactor)
Reactors used for research on nuclear characteristics of nuclear reactors, educational purposes, radiation and neutron irradiation experiments, etc.[20].
Prototype reactor (prototype reactor)
A near-practical prototype reactor built prior to the development of a particular type of power reactor[21].
Demonstration reactor (proven reactor)
Reactors recognized as being in the stage where economic efficiency and safety have been actually confirmed through the experimental stage[22].
Practical furnace
Practical stage nuclear reactor.At this stage the design is considered complete and a number of plants are built.

Classification by development generation

US Department of Energy (DOE) defined the development generation of nuclear reactors as follows in order to show the general concept of next-generation nuclear reactors advocated for practical use around 2030.[23].

1th generation (GEN-I)
Early reactors that went into operation in the 1950s and early 1960s
2th generation (GEN-II)
Commercial nuclear reactors built in the late 1960s and early 1990s
3th generation (GEN-III)
A nuclear reactor that started operation in the late 1990s and 2010s and was developed as an improved version of the second generation.[24]
4th generation (GEN-IV)
In a nuclear reactor that is currently under research in 2007,Natural gas thermal power generationHigh thermal efficiency, high safety, which can compete withRadioactive wasteInnovative reactor group with features such as minimization of burden and high proliferation resistance.高温ガス炉は、中国で商用炉が建設中であるHTGR is under construction in China[25].


[How to use footnotes]
  1. ^ Ministry of Land, Infrastructure, Transport and Tourism Geospatial Information Authority of Japan Map / Aerial Photo Viewing Service Aerial PhotoCreated based on
  2. ^ A reactor that maintains a controlled fusion chain reaction.Nuclear fusion reactorEspecially to distinguish fromFission reactorSometimes called.
  3. ^ Ahn (1980) p.26
  4. ^ There is no fusion reactor that can generate practical energy, but it is currently planned.ITER(International Thermonuclear Experimental Reactor) is expected to have a maximum output (heat output) of 50 kW.What is ITER design? (Japan Atomic Energy Agency)[Broken link]
  5. ^ It is said that it is still operating as a uranium deposit.
  6. ^ Thermal neutrons can successfully fission uranium-235.Although the name is thermal neutron reactor, the contribution of fast neutrons is also reasonable.
  7. ^ Besides,Thermal neutronsnot onlyFast neutronThere is also a reduced moderation reactor that is actively used.It is said that research has come to be carried out by improving the performance of computers and enabling precise simulation of the core.ATOMICA Progress and Challenges in Technology Development for Low Speed ​​Reactors
  8. ^ Since moderators are rarely used, neutron loss can be minimized.Glossary (1974) p.212 "Medium-speed neutron reactor"
  9. ^ Fast neutrons are easily absorbed by uranium-238, and uranium-238 that has absorbed neutrons becomes plutonium-239, so fuel growth is easy.On the other hand, fast neutrons are difficult to react with uranium-235, and the number of neutrons that can be used for nuclear fission is reduced by the amount absorbed by uranium-238, so it is necessary to make a reactor that can efficiently use neutrons.なお、高速中性子は核燃料から発生する超ウラン物質を核分裂させる能力にも優れ、このため、高速炉を高レベル放射性廃棄物のIn addition, fast neutrons also have an excellent ability to fission transuranium materials generated from nuclear fuel, which makes fast reactors high-level radioactive waste.Disappearance processingIt is said that it is being considered for use in.
  10. ^ 通常 のWedLight water has a large neutron deceleration ability, but also a large neutron absorption ability.Normally, the moderator also serves as the coolant.Light water is cheap and available in large quantities,Thermal power generationThe properties are well known because it is used in.On the other hand, since it has a large absorption capacity, it is necessary to increase the number of neutrons generated by using concentrated uranium fuel in a light water reactor.
  11. ^ Heavy water has a deceleration ability next to light water, but its absorption capacity is small.従って重水炉ではTherefore, in a heavy water reactorNatural uraniumVarious substances includingNuclear fuelCan be used as.However, heavy water is expensive.
  12. ^ carbonGraphite composed of graphite has a deceleration ability next to water and is solid at room temperature.Graphite is used in nuclear reactors designed to use a substance that does not have deceleration ability as a coolant, and because of its relatively simple structure, it is also used in countries with low nuclear power development capabilities.However, although the power generation efficiency is poor, it is often used for the production of plutonium for nuclear weapons because of the high production efficiency of plutonium-239.Currently, it is mainly used as a moderator for gas furnaces.
  13. ^ Enriched uranium must be used when light water is used as a moderator.
  14. ^ Light water may serve as both moderator and coolant, and moderator may be graphite or heavy water, and coolant may be separated from light water.
  15. ^ Unlike water vapor, gas can be heated to high temperatures without increasing pressure, so carbon dioxide was used as a coolant in early nuclear reactors.On the other hand, due to its low density and poor heat transfer capacity, commercial power generation using gas furnaces was inferior in economic efficiency, and the mainstream of commercial power generation furnaces was replaced by light water reactors.Helium is currently under research and development 1,000Every timeIt is being studied to use it as a coolant for a high temperature gas-cooled reactor that obtains a high temperature exceeding the above.Helium gas cooling is also being considered as a coolant for fast breeder reactors.なお、日本に初めて導入された原子炉は英国製のThe first nuclear reactor introduced in Japan was made in the United Kingdom.Gas cooled reactor.
  16. ^ Since liquid metal is a fluid with excellent heat carrying capacity that can obtain high temperature at normal pressure, it is not necessary to make the piping pressure resistant, and the entire reactor can be made smaller and lighter.For this reason, it was used as a power source for ships, but it was difficult to maintain a high temperature to keep the metal in a fluid state, and its use was limited to a small number.Sodium was used as a coolant for the nuclear reactors of early nuclear submarines.しかし、ナトリウムは水と激しく反応するため、旧ソ連のHowever, sodium reacts violently with water, so the former Soviet UnionAlpha classFor example, a nuclear reactor using a low melting point lead-bismuth alloy (used for etc.) as a coolant was adopted.Since sodium does not have neutron deceleration ability, it is used as a coolant for fast breeder reactors, and lead and bismuth are also being studied as coolants for fast breeder reactors.
  17. ^ In addition, although it is not a metal, molten salt is used as a coolant.Molten salt reactorThere are also nuclear reactors such as.
  18. ^ International Trends and Impact of Small Module Reactors (SMR)
  19. ^ Japan Broadcasting Corporation. “Is "Small Reactor" for Power Generation in a Decarbonized Society an Option?". NHK News. 2021th of February 5Browse.
  20. ^ Japan has the following research reactors.Nuclear White Paper 1961 "Research reactor'
    • JAERIJRR-1 Japan Atomic Energy Agency,Enriched uraniumLight water reactor(Water boiler type) 50kW,IbarakiTokai village, October 1957critical --September 1968 Shutdown --Decommissioning.
    • JAERIJRR-2 Japan Atomic Energy Agency, 90% (20%) Enriched UraniumHeavy water reactor(CP-5型)10MW、茨城県東海村、1962å¹´4月17日臨界(90%燃料) - 1970å¹´10月1日臨界(20%燃料) - 運用停止
    • JAERIJRR-3 Japan Atomic Energy Agency,Natural uraniumHeavy water reactor (domestic No. 1 reactor) 10 MW, Tokai Village, Ibaraki Prefecture, September 1962, 9 Critical.
    • JAERIJRR-4 Japan Atomic Energy Agency, Enriched Uranium Light Water Reactor (Pool Type) 1MW (Maximum 3MW), Tokai Village, Ibaraki Prefecture, January 1965, 1 Critical.
    • JAERIJPDR Japan Atomic Energy Agency, Enriched Uranium Light Water Reactor (BWR型)46.7MW(電力12.5MW)、茨城県東海村、1963å¹´10月26日初臨界、日本初の電力発電。1976å¹´3月18日運転終了 - 1996å¹´3月31日解体終了。
    • JAERIJMTR Japan Atomic Energy Agency, Enriched uranium light water reactor (tank type) 50 MW, Oarai Town, Ibaraki Prefecture, March 1968, 3 Critical.
    • JAERIHTTR Japan Atomic Energy Agency,Uranium dioxideGraphite furnace(GCRType) 30 MW, Oarai Town, Ibaraki Prefecture, November 1998, 11 Critical.
    • Kinki UniversityResearch Reactor (UTR-KINKI) Enriched Uranium Light Water Reactor (UTR-KINKI)UTRType) 0.1W (later changed to 1W),OsakaHigashi Osaka City(OldFuse City), November 1961, 11 Critical.Japan's first university-owned research reactor.
    • Rikkyo UniversityResearch Reactor (RUR) 20% Enriched Uranium (TRIGA-Type II) 100kW,KanagawaYokosukaSajima character Matsukoshi, December 1961, 12 Critical --Decommissioning.
    • Gotoh Educational SocietyResearch Reactor (MITRR) Tokyo City University(OldMusashi Institute of Technology), 20% enriched uranium hydrogenated zirconium furnace (TRIGA-II type) 100kW, Kanagawa PrefectureKawasaki CityOzenji, December 1961 Critical-Decommissioning.
    • Kyoto UniversityResearch reactor (KUR) 90% enriched uranium light water reactor (pool type) 1MW-5MW, OsakaKumatori Town, June 1964, 6 Critical.
    • 日立Research reactor (HTR) 10% enriched uranium light water reactor (tank type with pool) 100kW, Ozenji, Kawasaki City, Kanagawa Prefecture (inside TAIC Lab.), Construction cost is about 1.4 million yen. December 1961, 12 Critical. 25å¹´1962月にIn August 8Hitachi, Ltd.Was handed over to.Pause-Core dismantling.
    • ToshibaResearch reactor (TTR-1) 20% enriched uranium light water reactor (pool type) 30kW (maximum 100kW), Suehiro-cho, Kawasaki-shi, Kanagawa (in (NAIG Lab)), total construction cost is about 1.5 million yen. March 1962, 3 Critical--Pause.
    • MitsubishiResearch reactor 13% enriched uranium light water reactor (tank type) 30kW research reactor,Mitsubishi ElectricIn cooperation with, preparations were made to install it in Funaishikawa, Tokai-mura, Ibaraki Prefecture, and the installation was approved in August 1962, but the construction plan was canceled after that.
    • Tokyo UniversityResearch reactor (Yayoi) Enriched uranium air cooling 2kW, Tokai Village, Ibaraki Prefecture, April 1971 Critical. Scheduled to be suspended in March 4.
    • Power ReactorFast experimental reactor (Joyo)MOX fuelNa cooling fast neutron type (FBRType) 50MW, Naritacho, Oarai Town, Ibaraki Prefecture
  21. ^ Glossary (1974) p.97 "Prototype furnace"
  22. ^ Glossary (1974) p.152 "Demonstration Reactor"
  23. ^ Nuclear Encyclopedia "Generation IV Reactor (4-07-02-01)'
  24. ^ AP1000な ど
  25. ^ Nuclear Encyclopedia "Concept of Generation IV Reactor (4-07-02-01)'

Related item


  • "Latest Nuclear Energetics" Nuclear Fission "and" Nuclear Fusion "as Energy Technology" (Published by Gakken, April 1990, 4)
  • Hiroshi Ansei, Theory and Design of Reactors, University of Tokyo Press <Nuclear Engineering Series>, 1980.
  • "Illustrated Nuclear Term Dictionary" Nuclear Term Study Group (ed.), Nikkan Kogyo Shimbun, 1974, new edition.

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