China News Service, December 20. According to Kyodo News, Tokyo Electric Power Company disclosed that the monitoring of radioactive substances related to the discharge of nuclear sewage from the Fukushima Daiichi Nuclear Power Plant into the sea showed that the activity analysis of the radioactive substance tritium contained in fish was flawed.
Because the activity value detected by TEPCO using the existing method is higher than the actual value.
Data map: Fukushima Daiichi Nuclear Power Plant.
Tepco explained that since the analysis was carried out in a nuclear plant area, "the reason may be the mixing of tritium in the air" and it will be improved.
Since May, Tepco has analyzed the fish caught in the waters around the Fukushima No. 1 nuclear power plant, and a total of 10 Tepco and outsourcing units are responsible for the analysis.
The activity of tritium in fish is higher than that in seawater, and the numerical trend is different from the results of the Kyushu Environmental Management Association (Nine Rings Association for short) that has been analyzed in the past.
After comparing with the analysis method of the Nine Rings Association, it was found that TEPCO and the outsourcing unit used less reagents to remove impure substances.
After changing to the same method as the Nine Rings Association, the value obtained by the outsourcing unit is the same as that of the Nine Rings Association.
However, Tepco's analysis has not been improved even after adjusting the analysis method, and will continue to study methods such as changing to an area where tritium is considered to be less mixed.
Tepco plans to start discharging tritium-containing treated water into the sea around next spring. In order to know whether it will affect fish, it is collecting data for comparison before discharge.
On March 11, 2011, a magnitude 9.0 earthquake occurred off the coast of northeastern Japan and triggered a massive tsunami.
Affected by the earthquake and tsunami, a large amount of radioactive material leaked from the Fukushima Daiichi Nuclear Power Plant.
On April 13, 2021, the Japanese government formally decided to filter and dilute the Fukushima nuclear sewage and discharge it into the sea. However, this decision was widely questioned and opposed by the international community, and it also aroused strong concerns in Japan.