ALPS Treated Water Q&A
Q1: What is “ALPS treated water”?
A: “Contaminated water” and “ALPS treated water” are different.
“Contaminated water” contains a large amount of radioactive materials, and has been generated in buildings every day since the accident.
“Treated water” is water in which most of radionuclides* are removed by purification systems such as ALPS (Advanced Liquid Processing System) to meet the regulatory standards for discharge, with the exception of tritium.
Q2: Why is “contaminated water” generated?
A: Contaminated water is mainly generated from the following sources.
First, cooling water is provided to the fuel debris in order to keep the reactor under stable conditions.
Second, in order to prevent contaminated water in the reactor from flowing out of the building, groundwater is constantly flowing into the building.
Third, rainwater penetrates the roof of the building.
*Though various measures have reduced the amount of contaminated water generated from 540 m3 per day to about 140 m3 per day, it is difficult to completely reduce the amount generated to zero because the groundwater level is always above the water level inside the building.
Q3: What is tritium?
A: Tritium is a relative of hydrogen that emits a low level of radiation.
Tritium exists naturally and is found in rain water, sea water, tap water and inside the human body as a form of tritiated water.
Tritium is taken into the human body via drinking water and is excreted from the body, and then circulates in nature as the water does. It has not been confirmed to be accumulated in humans or specific organisms.
* Tritium concentration for tap water: 1 Becquerel/L
* Amount of Tritium in human body: tens of Becquerels
* The half-life of tritium radiation is 12.3 years.
Q4: Can tritium be removed?
A: It is very difficult to remove tritiated water from water, as it has the same properties.
Experts have concluded that there is no tritium separation technology that is immediately applicable to treated water with low concentrations and large volumes.
IAEA (International Atomic Energy Agency) is “not aware of a solution currently available for the separation of tritium commensurate with the concentration and the volume of treated water”.
Q5: Does the treated water contain radioactive materials other than tritium?
A: About 70 % of the treated water stored in tanks contains radionuclides other than tritium at the concentration which exceeds regulatory standards.
Since FY2020, re-purification of the treated water has commenced to meet the regulatory standards for materials other than tritium. In the case of releasing it to the environment, the treated water will be sufficiently diluted also to meet the regulatory standard for tritium.
*In its early years of operation, ALPS treatment has been carried out by prioritizing the volume of water treatment so that it can reduce the radiation impact to outside the site as soon as possible. There were also problems with cross filter permeation and other troubles that degrade the performance of ALPS treatment.
Q6: Why is discharge of ALPS treated water needed?
A: At Fukushima Daiichi Nuclear Power Station (FDNPS), water used for cooling fuel debris gets contaminated, treated, and then stored in tanks on site.
The storage tanks are projected to reach full capacity after the summer of 2022.
Meanwhile, the decommissioning of FDNPS is essential for the reconstruction of Fukushima.
Because of the need to complete reconstruction work such as retrieving fuel debris and storing waste temporarily, space for installing additional tanks on site is limited. When the decommissioning is completed, all the tanks must be removed. Therefore, the issue of discharging the treated water cannot be postponed forever.
Q7: Why was Discharge into the sea selected as the method of disposal?
A: The ALPS subcommittee suggested two options: “1) Vapor release” and “2) discharge into the sea” in February 2020.
Both option 1) and 2) are recommended to be realistic, because of the precedents and track records for them. “2) Discharge into the sea” can be implemented more reliably, considering the ease of discharge facilities operation and proper monitoring methods.
The International Atomic Energy Agency (IAEA) acknowledged that the options suggested by expert committee is “based on a sound scientific and technical basis of analysis”.
The Government selected discharge into the sea, based on the capacity to achieve consistent compliance with the regulatory standards set forth in the recommendations of the International Commission for Radiological Protection (ICRP); the successful track record of this practice in Japan; and the ability to conduct secure and sound monitoring.
＜Reference＞
- Statements made by IAEA Director General Rafael Grossi in February 2020
- IAEA Reviews Management of Water Stored at Fukushima Daiichi Nuclear Power Station (2 April 2020)
- TEPCO’s Draft Study Responding to the Subcommittee Report on handling ALPS-Treated Water (24 March 2020)
Q8: Is it possible to store or discharge treated water outside of Fukushima Daiichi NPS (FDNPS) ?
A: The decommissioning of FDNPS is essential for the reconstruction of Fukushima. Every day, decommissioning measures are taken to reduce risks on site, while preventing increase in risks at the surrounding areas. Both transferring the treated water and storing it in tanks outside the site are the activities which increase risks. In addition, it is necessary to obtain understanding from related local governments and local residents, which takes a considerable amount of time. Regarding offshore release, to carry the treated water and discharge it from a marine vessel is prohibited by international treaty (London Convention).
Q9: Is it possible to store in intermediate storage facilities?
A: The land for the intermediate storage facilities was provided by the landowners for specific uses of the facilities only. Therefore, it is difficult to use the land for other purposes.
(Ref.) Intermediate storage facilities are the facilities located at areas adjacent to the FDNPS, in order to temporarily store soil and other materials which have been collected during decontamination work in Fukushima, and which contain radioactive materials released from the FDNPS at the time of accident.
Q10: What regulatory standards are applicable to the discharge from Fukushima Daiichi NPS (FDNPS)?
A: Japan’s regulatory standards for discharge are set in compliance with the international standards known as publications of International Commission for Radiological Protection (ICRP), limiting additional public radiation dose below 1mSv/year. The national regulatory standards for tritium discharge stipulated in the ordinance of the Reactor Regulation Act is:
*Less than 60,000 Bq/L-water for tritium discharge into the sea.
Q11: What level of radioactive impact will the release of the treated water have?
A: The impact on the public and the environment are minimal. If the 22 trillion Bq per year of tritium and other radionuclides in the ALPS treated water will be discharged after treatment, the human exposure dose is approx. 1/70,000 to approx. 1/5,000 of natural radiation exposure (average in Japan: 2.1 mSv/year), and the exposure dose to animals and plants (flatfish, brown seaweed) is approx.1/50,000 to approx. 1/20,000 of the derived consideration reference level (DCRL) defined by the ICRP. (In the case of crab, approx. 1/500,000 to approx. 1/200,000).
Q12: What kind of countermeasures will be taken for possible reputational damage?
A: The safety of foods produced in Fukushima is confirmed by monitoring mainly before market distribution. As the GOJ reaches out and as the fact is known by overseas government, import restrictions have been eased and lifted. When the GOJ decides its policy on treated water, countermeasures for reputational damage will be strengthened, such as explaining scientific safety and developing sales channels.
Q13: What are the steps toward handling of treated water?
A: Considering the government’s basic policy, TEPCO will (1) develop the specific implementation plan, (2) obtain an approval from the Nuclear Regulation Authority, (3) construct necessary facilities, and (4) start the discharge procedures.
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