Portal field news

Portal field news


🌏 | Mr. Zelensky of Ukraine warns Russian soldiers attacking Zaporizhia nuclear power plant "Special target"


Ukraine's Zelensky warns Russian soldiers attacking Zaporizhia nuclear plant 'special targets'

If you write the contents roughly
Zaporizhia NPP has six pressurized water reactors and also stores radioactive waste.

On the night of the 13th, Ukrainian President Volodymyr Zelensky headed for the Zaporizhia nuclear power plant controlled by the Russian military... → Continue reading


From the news, readings, and feature articles of BBC journalists who interview in about 100 countries around the world, we select and deliver topics that are meaningful to Japanese users who are knowledgeable.

Wikipedia related words

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

6 pressurized water reactors

    Radioactive waste

    Radioactive waste(Hosha Sei is alive,British: radioactive waste) refers to used radioactive materials and materials contaminated with radioactive materials that are discarded without plans for future use.[1].

    It is generated with the use of nuclear energy represented by nuclear power generation.[2], also medical[3]and in agriculture and industryRadioisotope(RI) also occurs.In Japan, the laws and competent authorities that regulate the handling differ depending on the source.


    By definition, radioactive wasteRadioactive materialcontaining, i.e. harmful to humansradiationis released and its handling generally requires caution[4].Radioactive materials are classified according to their sources and properties, and disposal methods vary.[5].

    Under Japanese domestic law, there are different laws governing the handling of nuclear fuel materials and other radioactive isotopes (RI).In Japan, radioactive waste isLaw on waste disposal and cleaningIn principle, it does not correspond to "waste" defined in[6].However, if the level of radioactivity is below the clearance level or subject to exemption from regulations, the waste will not be legally regarded as radioactive waste and will be disposed of as industrial or general waste.

    In the case of radioactive waste from nuclear power plants,Reactortaken fromSpent nuclear fuel[7], clothing used by workers, and water used for decontamination.After temporarily storing spent nuclear fuel,Reprocessing plantWill be carried to.Reprocessing plantfrom the fuel rod parts, also fuel rodpelletincludeFission reactionProducts by (Fission products) or weturanium-plutoniumRadioactive waste such as waste liquid generated in the process of separating and extracting is generated.By type of generation, waste silver adsorbents for confining iodine, secondary waste (including those generated from MOX fuel facilities), etc., waste contaminated with uranium generated from facilities that process uranium fuel especially called uranium waste[8].

    Classification of radioactive waste in Japan

    Classification based on laws and regulations

    In Japan, by law, radioactive waste must be (a)Law Concerning Regulation of Nuclear Source Material, Nuclear Fuel Material and Reactorsay toRadioactive waste[9](Less than,nuclear fuel wasteand (b) other radioactive waste regulated by law (hereinafter referred to asRI waste) can be roughly divided intoFurthermore, RI waste

    (b-1)Law Concerning Prevention of Radiation Hazards Due to Radioisotopes, etc.RI waste from research fields inresearch RI waste) and
    (b-2)Medical law,Pharmaceutical Affairs Law,Veterinary lawas well as the Law on clinical laboratory engineers, etc.RI waste from the medical sector in Japan (hereinafter referred to asmedical RI wasteSay)

    Can be divided into[10].

    Due to special measures law

    Until 22, it was legally classified as above, but after the accident at the Tokyo Electric Power Company Fukushima Daiichi Nuclear Power Station on March 23, 3,Act on Special Measures Concerning Countermeasures for Environmental Pollution by Radioactive Materials Released by the Accident of a Nuclear Power Plant Associated with the Tohoku-Pacific Ocean Earthquake that Occurred on March XNUMX, XNUMX(Act on Special Measures Concerning the Handling of Radioactive Pollution) will be promulgated and enforced.Designated wasteas well as the Waste within the countermeasure areaA new classification of radioactive waste called “consisting of[11].

    Conventional classification with reference to the IAEA classification

    In Japan, radioactive waste is customarilySpent nuclear fuelThis refers only to the waste liquid mainly composed of nitric acid used for dissolution in the reprocessing of waste and its solidification.High level radioactive waste(High Level Waste,HLW[12]and anything elseLow level radioactive waste[13]classified into two[14].In addition, among low-level radioactive wastes, alpha emitters[15]that contain a large amount of alpha waste orTRU waste[16]called and further divided into[14].

    Systems and concepts related to "items that do not need to be treated as radioactive materials"

    Radioactive waste is usedRadioactive materialand items contaminated with radioactive substances that are discarded without plans for future use,radiationcan be detected most sensitively among physical phenomena, so in an extreme case, all waste can be treated as radioactive waste.However, in this case, the number of items to be regulated will be enormous, and the regulatory system itself will cease to function.

    In this way, even for radioactive substances within the framework of regulations related to radiation protection, in order for the regulations themselves to function well, the amount must be so small that the effects on human health can be ignored, or the regulations must be irrelevant. If there is almost no effect even if it is done, it is necessary to have a system and concept that it can be excluded from the regulatory framework as a substance that does not need to be treated as a radioactive substance.

    Even if it contains radioactive materials and is to be discarded, if these systems and concepts are applied, it will be out of regulation as radioactive waste depending on the conditions, such asWaste treatment methodBurial disposal as "waste" in[17]You will be able to

    clearance or exemption

    If the exposure dose caused by artificial radioactive materials is "sufficiently small compared to the radiation level in the natural world" and "the risk to human health is negligible," the idea is that it can be removed from the regulatory framework.clearancecalled (clearance)[18].In addition, the level to classify substances that do not need to be treated as radioactive substancesclearance level(clearance level)[19].

    It can be said that those containing radioactive materials to which the clearance system is applied pose a negligible risk to human health by definition.[20].

    in Japan since 1997Nuclear Safety CommissionIt is,IAEAtechnical documentation of[21]Based on the concept of clearance level calculation shown in the power reactor (Light water reactor, gas reactors, test and research reactors), etc.[22][23].

    regulatory exclusion

    natural radioactive material[24]If it is "impossible to regulate and there is no way to regulate" or "regulations have little effect" like exposure to radiation fromRegulation exemption(exclusion)[25].

    Exempted waste is not subject to regulation by definition, but it is not necessarily subject to the clearance system, so it is difficult to say that it is a waste that poses a negligible risk to human health.

    Treatment and disposal of nuclear fuel waste

    Nuclear fuel waste is conveniently further classified according to its source as follows:[26].

    power plant waste: Refers to waste generated from the operation, maintenance, and dismantling of nuclear power plants.[27].
    High level radioactive waste: Refers to the waste liquid mainly consisting of nitric acid used for dissolution in the reprocessing of spent nuclear fuel and its solidification.
    TRU waste : MOX fuelGenerated as a result of processing and operation/maintenance of spent nuclear fuel reprocessingTransuranium element(TRU) refers to waste contaminated with[28].
    Research laboratory waste: Refers to waste contaminated with nuclear fuel materials from research and development activities of universities and research institutes, not from power plants.

    Of these, TRU waste, which consists of high-level radioactive waste and extremely long-lived nuclides, which may have a serious impact on human health, is transported to deep geological strata.Geological disposal(Category XNUMX waste disposal) is planned.In addition, power plant waste is to be disposed of in three stages near the surface according to their physical properties.[29].

    Type XNUMX waste burial: Disposal method for low-level radioactive waste

    Disposal of low-level radioactive waste (Law Concerning Regulation of Nuclear Source Materials, Nuclear Fuel Materials and Nuclear Reactors (Law No. XNUMX of XNUMX) Type XNUMX Waste Burial)Margin depth disposal,Shallow underground pit disposal,Shallow trench disposalThere are three disposal methods for[30].Although all disposals except trench disposal are shielding type disposals, it is difficult to continue the complete shielding of radioactivity by man-made structures (engineered barriers) during the management period.In order to minimize the impact of radioactivity leakage, the location (geology, strata, water veins, etc.) and underground depth are taken into account in the disposal criteria.

    Margin depth disposal

    Sufficient leeway for common land uses (construction of houses, etc.) and underground uses (installation of foundations to support above-ground structures, subways, water supply and sewerage, use as utility tunnels and basements, etc.) At a certain depth (about 50 to 100 meters below ground), a concrete tunnel-type or silo-type artificial structure is created to bury waste.Margin depth disposalCall.Shroud[31], channel box[32], Spent control rods and other items with relatively high levels of radioactivity that are mainly generated during the decommissioning of nuclear reactors.[33].Management period is hundreds of years.Disposal and management methods, etc. are under investigation.

    Japan Nuclear Fuel OfSix low-level radioactive waste burial centersis under investigation as the next No. XNUMX facility.

    Shallow underground pit disposal

    A method of installing an artificial structure such as a concrete pit in shallow ground (approximately 10 meters underground) and burying the entire structure after bringing in the waste.Shallow underground pit disposalcall.Concentrated liquid waste, used ion exchange resin, incinerated ash from incineration of combustible materials, etc., solidified in drums with cement, etc., are mainly targeted for relatively low-level radioactivity discharged from nuclear power plants.[34].One guideline for the management period after burial is 300 to 400 years.

    Japan Nuclear Fuel OfSix low-level radioactive waste burial centersNo. 1992 and No. XNUMX facilities have been in operation since XNUMX.

    Shallow trench disposal

    A method of burying waste (so-called simple landfill) by digging a trench in the shallow ground and placing the waste as it is (no man-made structures).Shallow trench disposalcall.Of chemically and physically stable waste such as concrete and metal[35]Targets ultra-low-level radioactive waste with extremely low levels of radioactivity[36]. General land use becomes possible after a management period of about 50 years[37].

    power test furnace (JPDRMore) in order to dispose of the waste generated from the dismantling ofJapan Atomic Energy Agency・It has been implemented on a trial basis since 1995.

    Type XNUMX waste burial: Disposal method for high-level radioactive waste, etc.

    Of the nuclear fuel waste,High level radioactive wasteas well as the TRU wasteis geological disposal (Act on Regulation of Nuclear Source Materials, Nuclear Fuel Materials and Nuclear Reactors, Act No. XNUMX of XNUMX).Law on final disposal of specified radioactive wasteBased onNuclear Waste Management Organization (NUMO)will be the implementing body and dispose of it.

    Various methods have been considered for the disposal of high-level radioactive waste.[38]Ocean dumping(previously implemented in various countries, but completely banned in 1993), long-term storage at ground facilities (not implemented, except for temporary interim storage facilities), ice sheet disposal (prohibited), space disposal (outside the atmosphere by rocket) Release outside the gravitational sphere of the launch solar system, or pull it into the gravitational force of the sun (the US considered this method, but it was not adopted due to cost and uncertainty), and direct underground injection (implemented by the US and USSR)[39]etc., among which ocean dumping and direct injection into the ground were implemented.[40]. At the beginning of the 21st century, underground disposal has been adopted in many countries.

    Processing and disposal of RI waste (processing and disposal of waste from research facilities, etc.)

    In addition to nuclear facilities and nuclear weapon-related facilities, nuclear research facilities, universities,Medicalsector and private industrial sector,Agriculture:Radioactive waste is generated because there are cases where radioactive materials are used in other fields.

    Typical radionuclides contained in RI waste are 3H,14C,32P,35S etc., and as medical RI waste,99mTc,125I,201such as Tl. The majority of RI waste (research RI waste and medical RI waste) is collected and stored by the RI Association[41]. Regarding the disposal of RI waste, etc., in 2008Japan Atomic Energy AgencyIt was decided that the law would be amended[42].

    Treatment and disposal of specified waste, etc. stipulated in the Act on Special Measures Concerning the Handling of Radioactive Pollution

    TEPCOFukushima Daiichi nuclear power plantThe accident resulted in environmental contamination by radioactive materials released into the atmosphere.On August 23, 8, the so-called Act on Special Measures Concerning the Handling of Radioactive Pollution was promulgated in order to promptly reduce the impact of this on human health and the living environment (fully enforced on January 30, 24).[43].

    Based on this Act on Special Measures, the Minister of the Environment designates waste contaminated by accident-derived radioactive materials exceeding 8,000 Bq/kg.Designated wastecalled.Regarding the environmental impact of waste disposal, after collecting and analyzing data on waste incineration facilities in Tokyo and 1 prefectures,National Institute for Environmental Studies[44]has been confirmed by[45].


    [How to use footnotes]
    1. ^ Nagasaki and Nakayama (2011) p.4
    2. ^ Nuclear power plantandNuclear fuelmanufacturing facility,nuclear weaponsEmitted from related facilities
    3. ^ hospitalleave the inspection department ofGamma rayEmitted by disposal of sources.
    4. ^ Radioactive substances, including radioactive waste, have the property that after a certain amount of time (half-life) has passed, their radioactivity becomes weaker, and eventually most of them change into stable substances.Half-life and per unit timeRadiation doseis inversely proportional, and a substance with a long half-life has a small radiation dose per unit time.Half-lives vary by radionuclide.
      Among radioactive substances,Half-lifeare extremely long.After the half-life, the amount of radioactive material is reduced to half of the original amount, but it takes the same amount of time for the remaining radioactive material to become half (that is, 1/4 of the original amount).For example, it has a half-life of about 12 yearsTritiumIn the case of , the collapse does not end and disappear after 24 years. 12% of the original amount after 50 years, 24% after 25 years, 36% ​​after 12.5 years, and so on.Helium-3is generated.uraniumEtc.Atomic numberSubstances with a large λ also become radioactive substances (daughter nuclides) after decay, so it may take a very long time for all the radioactive elements contained in them to finish decaying and settle into stable isotopes such as lead. be.
    5. ^
      Classification and disposal method of radioactive waste
      Types of wasteExample of wasteGeneration sourceDisposal method
      High level radioactive wasteVitrified bodyReprocessing facilityGeological disposal
      Low level
      High level thingControl rods, furnace structures,
      Activated metal
      Nuclear power plantMargin depth disposal
      Low level thingWaste liquid, filter, waste equipment,
      Solidify consumables, etc.
      Shallow underground pit disposal
      Extremely low levelConcrete, metal, etc.Shallow trench disposal
      Waste containing transuranium nuclides
      (TRU waste)
      Fuel rod parts,
      Process waste such as waste liquid,
      Reprocessing facility
      MOX fuel processing facility
      3 stages other than trench disposal according to characteristics
      Uranium wasteConsumables, sludge, waste equipmentUranium enrichment
      Fuel processing facility
      All 4 stages of processing according to the characteristics
      Laboratory wasteUniversities, companies, etc.
      research Institute
      Radioisotope (RI)
      Medical institutions, etc.
      How to dispose of radioactive waste
      Disposal methodExample of wasteEnclosed containerArtificial structuredepthManagement period
      Geological disposalHigh level radioactive waste
      And TRU waste
      Vitrified canisterMultiple artificial barrier
      Reinforced concrete structure
      Deeper than 300mOver tens of thousands of years
      Margin depth disposalControl rods, furnace structures
      In activated metals and processing / reprocessing
      Process waste, etc.
      200 liter drums, etc.Reinforced concrete structure50-100mHundreds of years
      Management details undecided
      Shallow underground pit disposalWaste liquid, filter
      Waste equipment, consumables, etc.
      Put waste solidified with cement etc.
      200 liter drums, etc.
      Reinforced concrete structureDozens of metersAbout 300 year
      Shallow trench disposalCoCleat, metal, etc.Remains wasteNo artificial structureAbout 50 year
    6. ^ "Waste Disposal and Public Cleansing Law (Law No. XNUMX of XNUMX) Article XNUMX, Paragraph XNUMX". e-Gov Law Search.Administrative Management Bureau, Ministry of Internal Affairs and Communications (June 2017, 6). April 2020, 1Browse. “For enforcement on June 2018, 4”: (definition)
      Article XNUMX The term "waste" as used in this law means garbage, oversized garbage, cinders, sludge, excreta, waste oil, waste acid, waste alkali, animal carcasses and other filth or unnecessary matter in solid or liquid form. thing(Excludes radioactive substances and objects contaminated by them.).
    7. ^ In Japan, spent nuclear fuel is not classified as waste due to its reprocessing policy, but in countries that do not have a reprocessing policy, it is classified as high-level radioactive waste.
    8. ^ MilitaryIn the field, as similar waste, waste generated in the process of manufacturing nuclear weapons, nuclear weapons that have been scrapped after their useful life, and scrapped after their useful life have been disposed of.Nuclear submarine,Nuclear carrierand so on.
    9. ^ The law itself does not use the term "radioactive waste," but instead refers to "nuclear fuel material or material contaminated by nuclear fuel material" and "things to be disposed of."
    10. ^ Handling (1994) p.3,1. Situation surrounding RI/laboratory waste (Ministry of Education, Culture, Sports, Science and Technology),Nagasaki and Nakayama (2011) p.29
    11. ^ What is radioactive contaminated waste?
      In addition, each definition clause is as follows
    12. ^ Unlike the IAEA classification, it does not include radioactive waste that has strong radioactivity equivalent to reprocessing liquid waste and its solidified waste.In other words, all high-level radioactive waste is nuclear fuel waste.
    13. ^ Radioactive waste other than high-level radioactive waste is low-level radioactive waste.That is, almost all radioactive waste is low-level radioactive waste, regardless of its radioactivity intensity.
    14. ^ a b Doi (1993) p.42
    15. ^ nuclide that emits alpha rays
    16. ^ Transuranium elementradioactive waste containing a large amount of (TRans-Uranium)TRU wasteCall.
    17. ^ Of course, if it can be recycled as a resource, it will be reused.
    18. ^ Nagasaki and Nakayama (2011) p.66
    19. ^ Items that are recycled through clearance will be distributed to the general public, so there is a need for international consistency so that clearance levels do not vary greatly from country to country.International Atomic Energy Agency(IAEA) andEuropean Commission(EC), the clearance level is being studied. Nagasaki and Nakayama (2011) p.66
    20. ^ For example, radioactive cesium (cesium OfRadioisotope), the clearance level is 1 Bq per kg (100 Bq/g).
    21. ^ TECDOC855(1996)
    22. ^ Reactor Clearance (1999)
    23. ^ By the end of FY 62 (the end of March 2051), the amount of waste below the clearance level at uranium handling facilities is expected to be approximately 3 tons, of which 10 tons are metal. (The waste from the Fukushima nuclear power plant accident is not included.) The sources of these metals are centrifuges in the uranium enrichment process, roasting and reduction equipment in fuel processing facilities, molding equipment, sintering equipment, grinding machines, etc. be.It has been reported that 7.9-99.4% of transuranic radionuclides are concentrated in slag during melting of metals for reuse.Exceptions are Mn99.8, Fe54, Co55, Ni60, Zn63 (half gas and half ingot), Nb65, etc. Most of these isotopes remain in the ingot.
      Nuclear Safety Commission:"Metal waste below clearance level" View 2011-11-21
    24. ^ NORM: Called Naturally Occurring Radioactive Materials.Among NORMs, naturally occurring radioactive substances whose concentration is artificially increased are called TENORM (Technologically Enhanced NORM). Nagasaki and Nakayama (2011) p.67
    25. ^ Nagasaki and Nakayama (2011) p.67
    26. ^ Nagasaki and Nakayama (2011) pp.6-7, pp.28-29
    27. ^ Example: Absorbing neutrons in a radiation controlled areaRadiationmaterials near the core, waste from dismantling of decommissioned power plants, etc.
    28. ^ Examples: Nuclear fuel cladding tubes (hulls) generated from reprocessing plants, terminal parts (end pieces) of spent fuel structural members, etc.
    29. ^ Japan Nuclear Fuel"Disposal method of low-level radioactive waste"
    30. ^ "Regulations Concerning the Business of Type XNUMX Waste Disposal of Nuclear Fuel Materials or Materials Contaminated by Nuclear Fuel Materials (Prime Minister's Office Ordinance No. XNUMX of XNUMX)". e-Gov Law Search.Administrative Management Bureau, Ministry of Internal Affairs and Communications (June 2019, 7). April 2020, 1Browse. “For enforcement on June 2019, 7”are defined respectively in Article XNUMX-XNUMX of
    31. ^ What is a shroud?Boiling water reactorA cylindrical structure that houses the fuel assemblies and control rods that make up the core.
    32. ^ Fuel assemblyThe metal rectangular tube that covers the is called a channel box.
    33. ^ Nagasaki and Nakayama (2011) pp.128-130
    34. ^ Nagasaki and Nakayama (2011) p.127
    35. ^ In other words, even among wastes with extremely low levels of radioactivity, those containing harmful chemical substances are excluded.
    36. ^ Nagasaki and Nakayama (2011) p.126
    37. ^ trench disposal - Atomic EncyclopediaATOMIC
    38. ^ "Radioactive Waste WG Interim ReportʽMinistry of Economy, Trade and Industryʼ. April 2022, 7Browse.
    39. ^ Direct injection is a disposal method that involves injecting liquid or fluid mixed radioactive waste under high pressure into suitable soil for disposal. In 1957, the Soviet Union began a survey, injecting and disposing of tens of millions of cubic meters of low-level to high-level radioactive waste over 400 years into 1400m and 40m deep sandstone and limestone layers.In the United States, Tennessee for ten years in the 1970sOak Ridge National Laboratory300 cubic meters of low-level radioactive waste was injected 7500 meters underground, but was canceled due to concerns about environmental pollution.Disposal of high-level radioactive waste was also considered, but the plan was also abandoned due to concerns about contamination.
      World Nuclear Association “Storage and Disposal Options”
    40. ^ World Nuclear Association “Storage and Disposal Options”
    41. ^ Nagasaki and Nakayama (2011) p.28
    42. ^ Act to partially revise the Japan Atomic Energy Agency Act
    43. ^ What is radioactive contaminated waste? (Ministry of the Environment)
    44. ^ The National Institute for Environmental Studies has traditionally focused on research and support for the support of areas affected by the Great East Japan Earthquake.Efforts for environmental disaster research
    45. ^ summary version p.3


    全 般
    • Shinya Nagasaki, Shinichi Nakayama (co-edited), "Engineering of Radioactive Waste", Ohmsha, Nuclear Textbook, 2011. 
    • Kenkichi Hirose, "Guidance on Laws and Regulations Related to Nuclear Regulation," Taisei Publishing, 2011. 
    nuclear fuel waste
    RI waste (waste from research facilities, etc.)
    Specified waste (designated waste, waste within the countermeasure area)
    Systems and concepts related to "items that do not need to be treated as radioactive materials"

    Related item

    Related Organizations/Associations

    外部 リンク

    全 般
    RI waste (waste from research facilities, etc.)
    Specified waste specified in the Act on Special Measures Concerning the Handling of Radioactive Pollution


    Back to Top