July 22, 2022
International Environmental NGO FoE Japan
Today, the Nuclear Regulation Authority (NRA) approved an application for modification of the implementation plan for the installation of an offshore discharge facility for treated contaminated water from the TEPCO-Fukushima Daiichi Nuclear Power Plant. We believe that the following points should be taken into consideration: 1) radioactive materials should be centrally controlled and should not be released into the environment, 2) effective alternatives such as mortar solidification have been proposed, 3) there are strong objections from fishermen and citizens, and 4) there are many problems in the consensus building process as no public hearing or explanation meetings have been held since the decision on the ocean discharge policy. The company has long opposed the discharge of treated contaminated water into the ocean for a number of reasons.
The approval is problematic mainly in the following respects. The Nuclear Regulatory Commission is not fulfilling its role as a regulatory agency.
1. It is unclear what and how much will be released
Currently, approximately 1.26 million m3 (as of March 2022) of treated contaminated water is stored in tanks. In addition to tritium, strontium-90 and iodine-129 remain in this water, and nearly 70% of this water exceeds the sum of the notified concentration ratio of 1 (exceeding the standard). The total amount of these radioactive materials is not indicated. TEPCO has measured 64 radioactive materials (62 nuclides targeted for ALPS removal, tritium, and carbon-14) only for three tank groups, but not for many other tank groups at this stage. TEPCO has stated that the water exceeding the standards will be treated sequentially and measured before being discharged. However, the total amount will not be known until the discharge is completed, which is expected to take more than 30 years.
Also, tritium has been shown to be present in the tanks at 780 trillion becquerels (as of May 2021), but there is still a large amount of tritium in the debris and in the buildings. The total amount of tritium released is unknown because the amount of contaminated water will continue to increase as long as the inflow of groundwater is not stopped.
The review was conducted without providing crucial data on what and how much will be discharged.
2. Verification of radioactive materials other than the 64 nuclides and selection of nuclides to be measured before release were postponed.
TEPCO had identified 64 nuclides (62 nuclides to be removed from the ALPS, tritium, and carbon-14) as those to be monitored, but the Nuclear Regulation Authority had requested an explanation of the basis for the absence of residuals of other nuclides. In the end, however, TEPCO’s explanation remained the same and no new verification was conducted. TEPCO has explained that it will verify this point in the future and, based on this verification, will also indicate the radioactive materials to be measured prior to the release. In other words, the Regulatory Commission has approved the plan before TEPCO has even begun to specify the “verification” that it will conduct and the radioactive materials that will be measured prior to the release of radioactive materials.
The measurements of radionuclides and their concentrations in the three tank groups that TEPCO now indicates as source terms in its radiation impact assessment were not measured after the tanks were agitated. In other words, it should be noted that there is a possibility that they may have failed to capture materials that have settled at the bottom of the tanks.
3. No indication that ocean discharge is “for risk reduction and optimization”
As a result of the review, the Regulatory Commission stated that “future risk reduction and optimization of the specific nuclear facilities as a whole are being pursued.
However, risk reduction and optimization should not be achieved only within the Fukushima Daiichi Nuclear Power Plant site, but should be evaluated including the marine environment.
In addition, other alternatives must be considered in order to demonstrate that “ocean discharge is the way to reduce and optimize the overall risk.
TEPCO has not adequately considered the storage in large, robust tanks and the mortar solidification disposal proposal proposed by the Citizens Commission on Atomic Energy and other groups.
Although TEPCO cites the risk of leakage in the large tank proposal, large tanks have a long track record in oil storage, and sufficient countermeasures have already been established technically, including the installation of dikes to prevent leakage. Rather, the current storage in tanks is vulnerable, and the risk of leakage is high considering the planned offshore release period of more than 30 years. Regarding the mortar solidification disposal proposal, the proposer points out that water evaporates due to the heat of hydration, which can also be addressed.
It is inappropriate to conduct a review based solely on TEPCO’s views without obtaining the opinions of the proponents of these alternative proposals.
4. Priority should be given to drastic water sealing measures
The major source of contaminated water is the inflow of groundwater into the buildings. The frozen soil wall, which was constructed at great expense, has not been able to sufficiently stop the inflow of groundwater and is only a temporary facility. It has also been pointed out that it has not reached the bottom of the geological stratum, which allows water to pass through easily. Geological experts have proposed the construction of a wide-area impervious wall using existing technology, and TEPCO and the government should seriously consider these proposals and give priority to drastic measures to stop the inflow of water.