— Based on more than 6 years of comprehensive study by experts, reviews by the IAEA, and engagement with parties concerned, the Government of Japan published the Basic Policy on handling of the ALPS (Advanced Liquid Processing System) treated water at Fukushima Daiichi on 13 April 2021.
–Reference:
https://www.meti.go.jp/english/earthquake/nuclear/decommissioning/pdf/pr_bpalps.pdf
1.Latest progress of Fukushima Daiichi water treatment
— Amount of treated water[1]Amount of water between the bottom of a tank and the lower measuring limit of the water gauge. being stored is 1,255,771 m³. (as of April 15, 2021)
— At the Fukushima Daiichi, the radioactive substances in contaminated water are removed using a multi-nuclide removal equipment (ALPS) and the resulting treated water is stored in tanks on site along with Cesium/Strontium-treated water.
— There are 1,061 tanks on site. 1,020 storage tanks are being used for water treated with ALPS, 27 storage tanks are being used for Cesium/Strontium-treated water, 12 storage tanks are being used for fresh water treated with RO facility and 2 tanks are being used for concentrated seawater (as of April 15,2021).
— On December 11, 2020, the construction of tanks with a capacity of approximately 1,370,000 m³ was completed.
— Reference:
https://www.tepco.co.jp/en/decommission/progress/watertreatment/index-e.html
2.The Advanced Liquid Processing System (ALPS) for contaminated water treatment at the Fukushima Daiichi
— Contaminated water is purified using multiple pieces of equipment, and the key equipment among them is the Advanced Liquid Processing System (ALPS). As its name suggests, ALPS can remove as many as 62 kinds of radioactive materials except tritium.
3.Tritium contained in the ALPS treated water
— The total amount of tritium contained in treated water stored in the tanks at the Fukushima Daiichi premises is approx. 860 trillion Bq with an average concentration of approx. 730,000 Bq/L. (as of September 2020)
— References:
https://www.meti.go.jp/english/earthquake/nuclear/decommissioning/pdf/202009_alpsqa.pdf
https://www.tepco.co.jp/en/decommission/progress/watertreatment/images/200324.pdf
4.What is the nature of tritium?
— Tritium is a relative of hydrogen that emits weak radiation. It exists naturally and is found in the water such as water vapor in the atmosphere, rain, sea water, and tap-water.
5.How much could be the impact of tritium be on human health?
— We ingest tritium contained in tap water and it is also present in our bodies. Tritium, which we ingest in our daily lives, has a low concentration level. Even when we ingest (drink) it as water, it is excreted from our bodies more quickly than other radioactive substances. Therefore no impact on human health has been confirmed and it also does not accumulate in any specific organs in the human body.
— The amount of radiation emitted by tritium is so weak that it can be blocked with a sheet of paper in the air, so almost no external exposure can be detected. Health impact by intake of tritium to the human body is extremely low, around 1/700 of that of radioactive Cs-137.
6.Long-life radioactive elements such as carbon-14 contained in the ALPS treated water
— The concentration of carbon-14 in the treated water storage tank (80 tanks have been analyzed as of the end of June 2020) was 42.4 Bq/L on average [2]Minimum 2.53 Bq/L, maximum 215 Bq/L, compared to the government regulatory standard value (concentration limit) of 2,000 Bq/L.
— References:
- Treated Water Portal Site
https://www.tepco.co.jp/en/decommission/progress/watertreatment/index-e.html
- Concentration of radioactive materials by storage tank area
https://www.tepco.co.jp/en/decommission/progress/watertreatment/images/tankarea_en.pdf
- Distribution of the ratio of C-14 required by law in the ALPS treated water tanks
https://www.tepco.co.jp/decommission/progress/watertreatment/images/top/faq/c-14-e.pdf
7.Measures to meet the statutory standards for discharging treated water into the environment
— According to the TEPCO review draft published in March 2020 informed by the ALPS Subcommittee Report, if ALPS treated water were to be released into the environment, TEPCO will take measures to treat (and conduct secondary treatment of) the water appropriately using ALPS and other measures. As for nuclides other than tritium, if the sum of concentration limit ratios required by law exceeds, a secondary treatment and further diluting will be conducted to ensure the water meets all the regulatory standards including those for tritium.
— At nuclear facilities around the world, including Japan, it is common that liquid radioactive waste containing tritium is diluted and released into the ocean in a manner that complies with the regulatory standards of each country.
<The definition of “ALPS treated water”>
In light of the basic policy of the government and TEPCO Holding’s action in response to the government’s policy, the term “ALPS treated water” will be defined as, “water treated with multinuclide removal equipment (ALPS) so that the concentrations of radioactive materials other than tritium sufficiently satisfy regulatory standards for safety.” All other water will be defined as follows.(revised in April, 2021)
— Reference
https://www.tepco.co.jp/en/decommission/progress/watertreatment/images/20210427.pdf
8.Assessment regarding the effect of ocean discharge on neighboring area, such as China, Korea, and Taiwan
— According to a report TEPCO published in March 2020 that contains the results of the dispersion simulation of ocean discharge, even if 100 trillion Bq of tritium were to be released annually, only the area off the coast of Fukushima (approx. 10km to the north, 20 km to the south, 2km off the coast) would have tritium concentrations of 1Bq/L or more.
— Reference
https://www.tepco.co.jp/en/decommission/progress/watertreatment/images/200324.pdf
(Page 21)
9.JAIF’s communication activities with the neighboring Asian region about the Fukushima Daiichi Nuclear Power Station
— JAIF has implemented a wide range of activities to promote understanding of the actual status of the Fukushima Daiichi NPPsamong the international community by disseminating information about the status of the station in “Atoms In Japan,” the English website operated by JAIF, coordinating with relevant parties to secure opportunities for TEPCO to present the status of the Fukushima Daiichi in international conferences as part of bilateral or multilateral international cooperation initiatives, and having foreign parties involved in nuclear power participate in technical tours to the Fukushima Daiichi with TEPCO’s cooperation. In response to an increasing interest especially from nuclear power related personnel in the East Asia. JAIF has actively hosted these technical tours especially since around 2016.
References
