Sea Area Monitoring in Relation to ALPS Treated Water

From the perspective of securing safety and thoroughly ensuring measures against reputational damage upon the discharge of ALPS treated water, the national government and other relevant organizations have been conducting sea area monitoring. The monitoring has been conducted while ensuring the reliability of the relevant organizations' analytical abilities with the assistance of the IAEA.

In FY2022 before commencing the discharge, monitoring was started, and at present, precise analyses and rapid analyses are being conducted.

When monitoring detects any incident, such as a radioactive concentration exceeding the discharge suspension level, TEPCO is committed to making responses appropriately, including the immediate suspension of the discharge based on the Implementation Plan it had formulated.

Results of monitoring concerning tritium, etc. conducted by relevant ministries and agencies are published on the webpage titled "ALPS Treated Water Marine Monitoring Information. The government of Japan will continue making efforts to provide information domestically and internationally in a transparent and easy-to-understand manner.

ALPS Treated Water Marine Monitoring Information
https://shorisui-monitoring.env.go.jp/en/

(Source)

Prepared based on

• “Comprehensive Radiation Monitoring Plan (revised on March 21, 2024)” (Monitoring Coordination Meeting)
  https://radioactivity.nra.go.jp/cont/en/plan/meetings/274_20240321.pdf,
• “Status of Monitoring by MOE” (MOE)
  https://www.env.go.jp/content/000250315.pdf(in Japanese),
• “Sea Area Monitoring regarding ALPS treated water” (NRA)
  https://www.nra.go.jp/data/000457798.pdf (in Japanese)

• Included in this reference material on March 31, 2024
• Updated on March 31, 2025