Fukushima Inspection Team "Secured Raw Data of Concentrations Before and After Purification... Additional Analysis" [Q&A]

Director Yukukhee Briefing... "Will Secure Additional Data for Comprehensive Announcement"

On the 31st, the expert inspection team for the Fukushima nuclear power plant contaminated water announced that during the inspection process, they requested and secured raw data of the multi-nuclide removal facility (ALPS) inlet and outlet concentrations from Tokyo Electric Power Company (TEPCO).

Yu Guk-hee, chairman of the Nuclear Safety and Security Commission and head of the inspection team, stated during a briefing on the inspection results held at the Government Complex Seoul that morning, "We focused on checking the radioactive nuclide removal performance of ALPS and its potential for long-term stable operation." The contaminated water storage facility ‘K4 Tank’ and the purification facility ‘Multi-Nuclide Removal Facility (ALPS)’ are key data points for verifying the safety of contaminated water discharge.

However, the possibility of maintaining performance and functional suitability require further confirmation. It seems that the results judging the safety of contaminated water discharge will need to wait longer.

Yoo Guk-hee, head of the Japanese Fukushima nuclear power plant government inspection team, bows his head on the 31st at the Government Seoul Office in Jongno-gu, Seoul, before announcing the results of the inspection activities at the Fukushima Daiichi Nuclear Power Plant. Photo by Yoon Dong-joo doso7@

The inspection team visited Japan for 5 nights and 6 days from the 21st to the 26th and conducted on-site inspection activities. The team received data from facilities operated over four years, from 2019 to last year, for 64 nuclides analyzed annually. Among these, for about 10 nuclides with frequent detection history, they secured weekly measured inlet and outlet concentrations.

Additionally, through inquiries with TEPCO regarding the timing of adsorbent replacement in the ALPS facility, Yu explained that they received a response stating that replacement occurs after processing 8,000 tons of contaminated water and when purification capability declines as observed in weekly concentration analyses. Yu evaluated, "Through this inspection, we confirmed that the main facilities are installed on-site as designed and verified the means to block contaminated water discharge in case of abnormal situations. We also secured specific data, which represents meaningful progress in the scientific and technical review process."

However, he added, "For more precise judgment, additional analysis and verification are necessary. The possibility of long-term stable operation will be confirmed by analyzing the failure cases secured so far and by additionally securing ALPS regular inspection items and maintenance plans."

Yoo Guk-hee, head of the Japanese Fukushima nuclear power plant government inspection team, is announcing the results of the inspection activities at the Fukushima Daiichi Nuclear Power Plant on the 31st at the Government Seoul Office in Jongno-gu, Seoul. Photo by Yoon Dong-joo doso7@

Below is a Q&A session with Head Yu and the inspection team experts.

- What advances have been made beyond the International Atomic Energy Agency (IAEA)'s confirmatory monitoring?

▲ The IAEA is currently conducting confirmatory monitoring. This involves sampling Fukushima nuclear power plant contaminated water from TEPCO and having it analyzed by various authoritative institutions for cross-analysis. As mentioned, Korea’s Nuclear Safety and Security Commission is directly participating in this process. We handle the practical work related to the samples ourselves. Therefore, the actual verification program is conducted by the IAEA, which is expected to announce results soon. We have the practical handling of samples and analysis by the Nuclear Safety and Security Commission. What we are currently reviewing is whether Japan’s discharge plan is appropriate from scientific and technical perspectives, as Korea is the closest neighboring country to Fukushima contaminated water discharge.

- The issue is how accurate and reliable the raw data is. Please explain the verification of sample collection.

▲ Data reliability is the most important aspect we focus on. While explaining the chemical analysis building, we confirmed the stages from sample information to sample measurement through on-site demonstrations. This relates to the reliability of the data. The most critical part is how data management is handled from sample collection to analysis and measurement. We have requested additional data.

▲ Regarding sample collection, since the samples are from the stage after ALPS treatment of contaminated water, it seems you are referring to samples from the previous stage. While this has technical significance, what we must confirm clearly is the samples prepared for discharge. Therefore, focusing on verifying the concentration analysis of those samples is what we believe is important.

Yoo Guk-hee, head of the Japanese Fukushima nuclear power plant government inspection team, and the investigation team members are entering the press conference room at the Government Seoul Office in Jongno-gu, Seoul, on the 31st to announce the results of their inspection activities at the Fukushima Daiichi Nuclear Power Plant in Japan. Photo by Dongju Yoon doso7@

- About 60-70% of the contaminated water stored inside the tanks built around Fukushima nuclear power plant exceeds Japan’s own radiation standards. TEPCO’s basic policy is to keep running ALPS to re-purify the water until it meets the standard before discharge. Did you verify how this re-purification system operates?

▲ Currently, 70% of the contaminated water in tanks does not meet Japan’s discharge standards. The system itself does not have a separate nuclide removal facility; the piping lines are connected. So, if the water passing through ALPS does not meet discharge standards, it is recirculated through ALPS again. Regarding capacity, there are three types of ALPS facilities, and we confirmed each capacity. This can be checked by daily or annual processing capacity. Regarding your question about ‘if re-purification fails,’ obviously, if the discharge standards are not met, the water cannot be discharged at all.

- There are doubts and suspicions about TEPCO’s reliability.

▲ Regarding reliability, I mentioned data reliability. As you said, our evaluation activities are not based solely on what we see on-site or explanations we receive. We have had a review process, and we targeted areas where we thought on-site inspection was necessary. We went on-site, visually inspected the facilities, requested additional data, and conducted Q&A. Data reliability is very important to us as well. We conducted demonstrations at the chemical analysis building, verifying the process from sample arrival to measurement step by step. The purpose of the on-site inspection is to objectively verify and prove various Japanese plans and measures and to conduct additional precise analysis.

- Is there a possibility that additional analysis will not be completed before discharge?

▲ We are trying to speed up the analysis process.

Yoo Guk-hee, head of the Japanese Fukushima nuclear power plant government inspection team, is announcing the results of the inspection activities at the Fukushima Daiichi Nuclear Power Plant on the 31st at the Government Seoul Office in Jongno-gu, Seoul. Photo by Yoon Dong-joo doso7@

- You mentioned focusing on the capability to shut off in case of abnormalities such as emergency shut-off valves or flow meters. The report says ‘confirmed,’ but was there a demonstration?

▲ (Jung Gu-young, Head of Nuclear Safety Division, Korea Institute of Nuclear Safety) Regarding the emergency shut-off valve test, I will explain what we actually observed. This shut-off function is typically activated when contaminated water is discharged from the transfer pump; if the radiation detector senses radiation above a set threshold, it should automatically shut off. TEPCO conducted tests using simulated signals. Although the facility is still under construction, the shut-off valves are already installed. We reviewed the control function to see if it actually shuts off with simulated signals. Also, the emergency shut-off valve can be manually shut off by an operator’s judgment. TEPCO had video evidence of tests for this function, which we reviewed.

▲ (Kim Sung-il, Senior Researcher, Radiation and Waste Evaluation Division, Korea Institute of Nuclear Safety) Regarding ALPS malfunctions, I will respond to your inquiry. As you mentioned, TEPCO operates three types of ALPS. The initially installed one, called the existing ALPS, has been operating since 2013. Then, an additional ALPS was added in 2014, and a high-performance ALPS was also installed and operated. We received data on major failure histories and responses from the existing ALPS since 2013, including causes.

- You said you will verify now and continue monitoring in the future. Is there a possibility to directly collect samples during the monitoring process?

▲ As mentioned earlier, the IAEA plans long-term monitoring since the contaminated water discharge is planned over a long period. This will be conducted as part of international verification.