IAEA "Trust in Japan's Monitoring System for Fukushima Discharge"

The International Atomic Energy Agency (IAEA) has evaluated that the monitoring system by Japanese authorities for the treatment process of contaminated water from the Fukushima nuclear power plant, scheduled for discharge this year, is reliable. However, it expressed the opinion that additional explanations are needed regarding the impact of the contaminated water discharge and the methodologies used to measure the concentration of radioactive materials.

On the 5th (local time), the IAEA announced this through its 4th report, which was prepared based on on-site investigations conducted by experts to verify the treatment process of contaminated water at the Fukushima Daiichi Nuclear Power Plant. This report is limited to the investigation of the contaminated water treatment and discharge process conducted by IAEA experts who visited Japan in November last year. The final report will be prepared after the 5th and 6th reports, which will include results from investigations of marine water samples collected on site.

This 4th report focused on verifying and evaluating the monitoring system for the marine water discharge process by Tokyo Electric Power Company (TEPCO) and other Japanese authorities. The report confirmed that the program established by TEPCO to monitor environmental impacts after the contaminated water discharge is reliable and has a sustainable radiation protection system, based on supplementary information provided by Japan in response to IAEA’s requests.

[Image source=Reuters Yonhap News]

The report also evaluated that there was significant progress in supplementing the monitoring plan after hearing the opinions of IAEA experts. The report included experts’ opinions that no further technical review of this plan is necessary. However, the report suggested that additional explanations from Japan are needed regarding some aspects related to the Radiation Environmental Impact Assessment (REIA).

Among the plans to assess the impact of radioactive materials after discharge, a more detailed explanation is required for the exclusion of fish consumption caught within 3 km off the coast, and a clear explanation is needed regarding the uncertainties in the formation process of organically bound tritium (OBT) within organisms.

Additionally, estimates of concentrations of residual radionuclides such as iodine (I-129) and carbon (C-14) in seawater at the boundary of the environmental impact simulation area were also requested.

The contaminated water from the nuclear accident is stored in hundreds of tanks within the nuclear power plant site, and TEPCO explains that this water is "treated water," from which most radioactive nuclides have been removed through the Advanced Liquid Processing System (ALPS) and other processes.

However, tritium, a radioactive material, remains even after purification. The Japanese government plans to dilute the tritium concentration in the contaminated water to less than 1,500 becquerels (Bq) per liter, which is 1/40th of the national regulatory standard, and begin discharging it starting this year.

The IAEA has been conducting work to verify whether this plan will have any adverse effects on the environment. This involves analyzing the characteristics of the contaminated water’s radioactivity and assessing the overall environmental impact of the discharge process. The IAEA plans to release the final report before Japan begins the discharge within this year.

Earlier, in April 2021, the Japanese government officially decided to discharge the contaminated water accumulated over 10 years since the Great East Japan Earthquake in 2011, after a single discharge immediately following the disaster, into the ocean over approximately 30 years starting this year.

This content was produced with the assistance of AI translation services.