Fukushima to add 3 marine monitoring spots for nuclear wastewater

Photo: Chart shows the prefectural government's planned monitoring spots near the exit of a tunnel about 1 km offshore, through which treated wastewater is to be released into the sea.

The Fukushima prefectural government is set to strengthen in fiscal 2022, beginning on April 1, its system for monitoring the planned release into the ocean of wastewater treated but still containing radioactive tritium from the crippled Fukushima Daiichi nuclear power plant of Tokyo Electric Power Company Holdings Inc. The move to add three marine monitoring spots to the existing six is based on the national government's plan to start discharging wastewater into the sea off the plant in the spring of 2023. The local government will expand its own monitoring framework and announce the results broadly at home and abroad in efforts to help ensure the safety of prefectural people and restrain reputational damage. The proposed enhancement of monitoring was presented to a meeting of the prefecture's panel for assessing environmental monitoring programs, which was held online on Feb. 25. Given simulated marine diffusion of discharged wastewater, published by the utility known as TEPCO, the prefecture picked the three new spots assuming that tritium content may increase there through wastewater release. The prefecture will use the observation spots to monitor changes to the amounts of 14 radioactive substances, including tritium, strontium and plutonium. TEPCO plans to gauge the content of these substances in wastewater and dilute it with seawater before discharging it at a point about 1 kilometer off the plant through an undersea tunnel. The additional monitoring points include locations near the exit of the tunnel. Measurement at the additional spots will be conducted four times a year before the release begins in order to capture seasonal variations of seawater, while the frequency will be increased to a monthly basis after discharging starts to follow changes in the density of radioactive substances. Seawater samples will be analyzed at the Fukushima Prefectural Centre for Environmental Creation, with the outcome due to be published on the prefecture's website and elsewhere. In connection with the oceanic monitoring of released wastewater, the Nuclear Regulation Authority is to increase tritium-measuring points from 12 currently to 20. The Environment Ministry will add about 30 points to bring the total to around 50. TEPCO plans to boost the number of its own from 23 to 35. At the prefectural panel meeting, a member pointed out that measurement results from the three parties -- the central and prefectural governments and TEPCO -- should be evaluated and analyzed in an overall, integrated manner so as to ensure the objectivity and transparency of information and data. Concerns remain strong over a fresh emergence of harmful rumors regarding the oceanic release of treated wastewater among people in a wide range of industries, particularly those in the fisheries, as well as local municipal assemblies and other quarters.