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The IAEA Published a Report on Its Second Review Mission of Safety Aspects of Handling of ALPS Treated Water at Fukushima Daiichi Nuclear Power Station in November 2022

The IAEA Published a Report on Its Second Review Mission of Safety Aspects of Handling of ALPS Treated Water at Fukushima Daiichi Nuclear Power Station in November 2022

April 6, 2023

On April 5, the IAEA (International Atomic Energy Agency) published the report on its second review mission of Safety Aspects of Handling of ALPS treated water at Fukushima Daiichi Nuclear Power Station (FDNPS). The report is based on the review conducted when the IAEA officials and international experts visited Japan from November 14 to 18, 2022.

1. Summary

The review mission of Safety Aspects of Handling of ALPS treated water at FDNPS in November 2022 was conducted based on the Terms of Reference (TOR) on a comprehensive framework for cooperation on the handling of ALPS treated water, which was signed with the IAEA July 2021. This is the second review mission. The IAEA’s review has been conducted by the IAEA Task Force, which consists of IAEA officials and international experts.
This report mainly describes the findings of IAEA’s review in November 2022 in accordance with international safety standards.

(Reference) The IAEA Task Force includes international experts, serving in a personal capacity, from Argentina, Australia, Canada, China, France, Republic of Korea, the Marshall Islands, Russia, the United States, the United Kingdom, and Vietnam.

2. Key Points of the Report
*There are quotes from the IAEA report (Including some summaries)

As in the previous report, the following each eight technical items were reviewed.

i. Crosscutting Requirements and Recommendations

ii. Characterization of discharge and source term

iii. Safety Related Aspects of Systems and Processes for Controlling Discharges

iv. Radiological Environmental Impact Assessment

v. Regulatory Control and Authorization of Discharges

vi. Source and Environmental Monitoring Programmes

vii. Involvement of Interested Parties

viii. Occupational Radiation Protection

The report includes the key points of discussion between the IAEA Task Force and METI and TEPCO and summary of the Task Force’s findings on each technical item.

In addition, the report highlights that TEPCO has taken account of the issues raised during the previous technical mission in February 2022 and has made significant progress to update its plans in accordance with feedback from the Task Force and IAEA has gained a better understanding, and no further missions to TEPCO and METI are necessary.

Main review item

(1) Crosscutting Requirements and Recommendations

In the first mission to TEPCO and METI, the Task Force noted that they received the full cooperation from counterparts in Japan and received many presentations and references materials that helped to set the basis for the IAEA review.
The Task Force did not request any additional information from METI and TEPCO relevant to the requirements and recommendations included in the IAEA’s international safety standards applicable to the review.

(2) Characterization of discharge and source term

The Task Force had an overall view that the revised methodology for characterizing the source term is sufficiently conservative yet realistic.
The Task Force reiterated that TEPCO must repeat the calculation of doses to the public and the environment in the radiological environmental impact assessment (REIA) using the more realistic representative source term now that this was available.

(3) Safety Related Aspects of Systems and Processes for Controlling Discharges

The Task Force understands that an appropriate analysis of possible accident scenarios and the consequences thereof was conducted and included as part of the revised implementation plan submitted to the NRA for approval.
The Task Force had no remaining questions for TEPCO regarding this technical topic, and TEPCO did not request clarification on any statements or follow up by the Task Force.
Based on the Task Force’s review of the updated implementation plan, including key portions of the REIA, the Task Force has noted that the issues identified in the first ALPS report have been addressed in an appropriate manner.

(4) Radiological Environmental Impact Assessment

In general, the remaining technical issues do not prevent the IAEA from drawing conclusions regarding whether TEPCO is adhering to the relevant IAEA international safety standards.
Following this mission, TEPCO further updated the REIA in February 2023 and addressed the remaining comments from the Task Force on the REIA except for outstanding comments from the Task Force on the source term.
The Task Force suggested that TEPCO include the following in REIA. The Task Force strongly believes the following points listed should be clearly documented so that interested parties can more easily understand the assumptions and calculations made as part of the REIA.

i. a clearer explanation of the dose calculation to the representative person over the proposed period of discharge, such as explaining that for dose pathways relating to sediments, the dose predicted for the first year (assuming equilibrium
between seawater and sediments) is equivalent to the highest dose in the 30-year period;

ii. a clearer explanation of the uncertainty in OBT formation and the associated doses, and consider performing the calculation assuming 100% OBT to definitively show that this assumption does not have a meaningful impact on the final
estimated dose to the representative person;

iii. estimates of C-14 and I-129 concentrations in sea water at the boundary of the simulation area and other radionuclides
that contribute significantly to the dose.

(5) Monitoring

1. Source Monitoring

The Task Force was content that homogeneity was demonstrated by this test (circulation and agitation test) and that the extent of sampling undertaken was adequate.
TEPCO agreed that the maintenance plan for the measurement and confirmation facilities could be shared with the Task Force prior to the start of discharges.

2. Environmental Monitoring

From the presentations made by TEPCO during the mission and the REIA, the Task Force understands TEPCO’s environmental monitoring programmes and agrees, based on this information, that it is comprehensive.
The Task Force requested TEPCO to describe how the results of environmental monitoring after the discharges start will be compared against the baseline and how this comparison will be used to assess any measurable impacts from the discharges of ALPS treated water.
The Task Force requested TEPCO to explain what actions would be taken if the measurements indicate the dose to the representative person is different to the dose predicted in the REIA.

(6) Involvement of Interested Parties

The Task Force acknowledged the significant outreach activities and efforts by TEPCO and METI to ensure transparency.

(7) Occupational Radiation Protection

The Task Force confirms that TEPCO has a reliable and sustainable radiation protection programme with the necessary commitment and ownership.
Assuming long-term operation, the Task Force encourages TEPCO to consider establishing an internal mechanism for the reassessment of ALPS facilities and equipment on a periodic basis while taking into account the evolution of the radiological conditions in the relevant areas and during operation in the future.

3. Response to the IAEA report

The points raised by the IAEA Task Force have been reflected in the revised REIA attached in the Implementation Plan, which TEPCO submitted to the NRA in February 2023, and the contents of the revised REIA report are thus further enhanced.

Through the IAEA review, the Government of Japan will continue to take measures in accordance with international safety standards and take all possible measures to ensure safety.