Brochure (4-page PDF in B5 version))
The problem of “treated water” at the Fukushima Daiichi nuclear power plant continues to increase, with recent reports on TV and newspapers.
The site is full and a government committee has released a report highlighting the benefits of ocean releases, but what’s the truth? Below are answers to frequently asked questions.
Q: First of all, what is “treated water”?
A: At the Fukushima Daiichi nuclear power plant site, contaminated water from the mixing of fuel debris cooling water with groundwater flowing into the reactor building and turbine building is passed through the Multinuclear Species Removal Unit (ALPS) and placed in a tank. save (picture). This is called “treated water”. There are already 979 water tanks, storing 1.19 million cubic meters of treated water (as of March 12, 2020).
To be precise, it is “water treated with ALPS but containing radioactive substances”, but because of the length of the article, “treated water” is used here.
Q: What does “treated water” include?
A: TEPCO estimates it contains about 860 trillion becquerels of tritium. 2010 Fukushima Daiichi Nuclear Power Plant2.2 trillion becquerelsTritium is released into the sea (Note 1)About 390 times that amount.
ALPS should be able to remove radioactive materials other than tritium. To this end, Tepco and the Ministry of Economy, Trade and Industry call it “tritium water”. However, in August 2018, Kyodo News and other media exclusively reported (Note 2)Clearly, other nuclides such as iodine-129, ruthenium-106 and strontium-90 remain above the norm. With the subsequent announcement of Tepco,About 70% of the water currently stored in tanks contains concentrations of 62 radionuclides other than tritium that generally exceed discharge standards by as much as 20,000 times the standard (Note 3).(Fig.).When Tokyo Electric Power was released to the oceanSecondary processingAnd these radionuclides are also below standard values.
Q: What is tritium?
A: It is the isotope of hydrogen “tritium”, which consists of one proton and two neutrons. A radioactive material with a half-life of 12.32 years that undergoes beta decay into helium.
The energy emitted is very small, with a maximum of 18.6 keV, which is about 1/30 of the maximum of 512 keV for cesium 137. Tritium is also found in nature in the form of water, but it is increasing due to emissions from nuclear testing and nuclear facilities.
Q: Is tritium safe?
A: About the effect of tritiumEven experts disagree..government,“Because it has the same properties as water, it has not been confirmed whether it is concentrated in humans or living organisms.”It is said.
but tritiumSubstitute hydrogen in organic compoundsWhen replaced by the substances that make up the body through food, it stays in the body for a long time, affecting nearby cells, andWhen replaced by the hydrogen that makes up DNAIt has been pointed out that when tritium is converted to helium, the effects of radiation exposure become stronger and DNA is damaged. (Note 4)
Q: Is there no realistic means other than releasing it overseas?
Answer: GovernmentAround the summer of 2022, there will be no more open space at the nuclear power plant site where storage tanks can be installed.It is said.
However, marine release is not the only option. The technical subcommittee of the “Nuclear Citizens Committee”, a private think tank, in which many factory engineers also participate,“Large Tank Storage Plan”, “Mortar Solidification Disposal Plan”Proposing. (Note 5)
Q: What are the benefits of storing in large jars?
A: The large tank plan is to build a large tank of about 100,000 cubic meters with a dome-shaped top cover and water-sealed vents. We propose to select the construction site from the planned site, dump site, site hinterland, etc. of Units 7 and 8 with the consent of the local community (pictured). By constructing 20 tanks on a site of 800m x 800m and gradually replacing the existing tanks with larger tanks, the newly generated treated water (150 m3 per day) can be stored for about 48 years.Large storage tanks are used for oil storage, etc., with outstanding achievements, and are stronger than current storage tanks.Yes.
By storing it in a large tank, you can expect the damping effect of tritium.
Q: What is a “mortar curing disposal plan”?
A: The “Mortar Solidification Program” is a method used in wastewater treatment at the Savannah River nuclear facility in the United States.The treated water is cured with cement and sand in a huge concrete container and treated in a semi-subterranean state.(Photo). The advantage is that the risk of radioactive material leaking into the ocean can be stopped semi-permanently. In addition, the treated water after curing will also decay in the same way, so it is safe enough for future deterioration of concrete and mortar. However, since cement and sand are mixed together, the volumetric efficiency is about 1/4.despite thisIf you have an 800m x 800m site, you can store treated water in mortar for about 18 years... It was considered a “solidification/underground burial plan” among the options of the Ministry of Economy, Trade and Industry task force, but it was not considered and has been narrowed down to one of the cheapest marine release plans. ..
Q: Is the website really not enough?
One:On the north side of the site, there is an area that is currently a garbage dump.TEPCO explained that the radioactive material contained in the soil was “several becq/kg to several thousand becq/kg”.
The “Water Treatment Subcommittee for Multinuclide Removal Equipment, etc.” under the Ministry of Economy, Trade and Industry also discussed whether the site is really insufficient.from the committee“If the site is not enough, I think we should expand the site of the Fukushima Daiichi nuclear power plant.” “Can’t the soil be transported from the dump site to the temporary storage facility?”However, the government said it was “difficult to gain local understanding”. (Note 6)
On the other hand, on January 22 of this year, at the water treatment rally held in the House of Representatives, Mr. Masumi Kowata, a member of the Okuma Town Council, said, “Even for Okuma Town residents, “
Q: What do the fishermen say?
A: Local fishermen, including Satoshi Nozaki, president of the Fukushima Prefecture Fisheries Federation, have expressed their opposition on many occasions. “Even though we have come so far to rebuild, if anything happens, the fishery will be devastating.will. “Ohama Mechanical Bottom Trawling Fishery Cooperative President Yanai Takayuki said: “The release of the ocean will be in a deadlock for a long time. We cannot see the future and make capital investments. “
In February 2020, the Ibaraki Coastal Area Fisheries Cooperation Association also asked the prefectural governor not to discharge the treated water into the sea. In this regard, Ibaraki Prefecture Governor Kazuhiko Kazuhiko said, “I hope everyone will reconsider at the blank stage” in response to the council’s conclusion that marine releases are realistic.
Q: Can it no longer be used as cooling water?
A: For part of the polluted water generated in the building, the water from which salt, cesium and strontium have been removed is used as cooling water again. Taking into account the balance of water balance, groundwater flows into the building, so the water intake is stored in the tank as treated water.
Q: What is the public opinion in Fukushima Prefecture?
A: According to a February 2020 poll of voters in Fukushima Prefecture jointly conducted by Asahi Shimbun and Radio Fukushima, 57% of people “oppose” diluting “treated water” and flushing it into the sea. (“Agree” is 31%)). (Note 7)
Q: Are there any restrictions on tritium?
A: Tritium is used as a standard for emission concentrations.60,000 becquerels/litersupply.
set annual emissions targets for each nuclear facility,Take the Fukushima Daiichi nuclear power plant before the nuclear accident as an example, 22 trillion becquerels per yearYes. This target has not been used since the nuclear accident, but if it were to be achieved, it would take decades to release 860 trillion becquerels of tritium.
When discharging water from secondary drains and groundwater bypasses, TEPCO will set tritium release limits based on the legal limit (1 mA) for exposure doses around the site.1500 becquerel/literIt is said.
The standard range of tritium concentrations in drinking water is wide,WHO is 10,000 becquerels/LCanada 7,000 becquerels/liter(Recommendation of the Ontario Drinking Water Advisory Committee20 becquerel/liter), America740 becquerel/literEU100 becquerel/literIt becomes. This may be due to disagreement over the health risks of tritium. The WHO standard frequently cited by Tokyo Electric Power and the Ministry of Economy, Trade and Industry is higher than that of Canada, the United States and the European Union.
> Related information: Study group: Everything you need to know about ALPS-treated contaminated water
Note 1) Ministry of Economy, Trade and Industry “Multiple Nuclide Removal Equipment Treatment Water Treatment Subcommittee (No. 16)” Document 4
Note 2) Kyodo News “Detection of Radioactive Substances Exceeding the Standard Value/Long Life Except Tritium” published on August 19, 2018
Note 3) Ministry of Economy, Trade and Industry “Multi-nuclide Removal Equipment Treatment Water Treatment Subcommittee (No. 10)” Document 3
Note 4) Masaichi Nishio, honorary director of the Hokkaido Cancer Center, frequently points out the danger of tritium being incorporated into DNA. For example, see below.
> Briefing Hearing on “Water Treatment Subcommittee on Treatment of Multinuclide Removal Equipment and Others”
> “On the Health Hazards of Tritium” (Citizens Cancer Treatment Association)
Other materials are, for example, as follows.
> Toshiyuki Mada “Assessment of Tritium’s Biological Effects” (“Hospital University of Occupational and Environmental Health” Vol.31 No.1 (2017) p.25)
>Ian Fairlie, Explaining Hypotheses for Childhood Cancer Near Nuclear Power Plants, Journal of Environmental Radioactivity, Vol. 133, July 2014, pp. 10-17
> Chihiro Uesawa, “Three Stones Contaminated Water at Fukushima Daiichi Nuclear Power Plant” (“Science” May 2013)
>Tim Deere-Jones (Marine Radioactivity Research & Consultancy: Wales: UK), Proposed discharge of tritiated water and stored tritiated water at the Fukushima accident site
Note 5) Nuclear Citizens Committee “Opinions on Treatment of ALPS Treated Water”
Note 6) The 13th and 14th multi-nuclide removal equipment water treatment sub-committee, etc.
Note 7) Asahi Shimbun “Fukushima Daiichi Nuclear Power Plant Processes Water, Seawater Release” against “57% of the prefectural public opinion”
Ministry of Economy, Trade and Industry “Multi-nuclide removal equipment and other treatment water treatment subcommittee” report/document
Nuclear Citizens Committee “Opinions on Treating ALPS Treated Water” October 3, 2019
January 22, 2020 “Study Group: The Future of ALPS Treating Contaminated Water – Abandoned Land Storage Scheme” material
Tokyo Electric Power Company Holdings, Inc. “Draft Study on Our Subcommittee Report on Treatment of Water Based on Multinuclide Removal Equipment” (March 24, 2020)
*We would like to thank the following people for their cooperation in writing this Q&A. Thank you.
Junichi Onuma (Nuclear Citizens Committee, former senior researcher at Aichi Environmental Research Center)
Mr. Yasuro Kawai (Nuclear Citizenship Committee, former plant engineer)
Hideyuki Ban (Citizen Nuclear Information Center)
Shuzo Mizuto (Shinzaburo Takagi Citizen Science Foundation)
International Environmental NGO FoE Japan