Japan Starts Second Discharge of Fukushima Contaminated Water... 7,800 Tons Released into the Sea

Tokyo Electric Power Company (TEPCO) began the second phase of ocean discharge of contaminated water from the Fukushima Daiichi Nuclear Power Plant at around 10:20 a.m. on the 5th.

According to Kyodo News, TEPCO announced that during the second discharge period, from this day until the 23rd of this month, it will release approximately 7,800 tons of contaminated water, the same scale as the first discharge. The daily discharge volume is expected to be around 460 tons.

TEPCO dilutes the contaminated water stored in tanks on the Fukushima Daiichi Nuclear Power Plant site, which has passed through the Advanced Liquid Processing System (ALPS), with a large amount of seawater and releases it into the sea in front of the plant through an approximately 1 km long underwater tunnel.

Even after purification treatment with ALPS, trace amounts of radionuclides such as tritium and carbon-14 remain. Tritium, which cannot be filtered by ALPS, will be diluted with seawater to a concentration below 1,500 becquerels (Bq) per liter, which is 1/40th of Japan’s regulatory standard, before being discharged into the ocean.

TEPCO stated that during preparation work the previous day, the tritium concentration in the contaminated water diluted with seawater was measured at 63 to 87 Bq per liter, which is below the discharge standard.

Additionally, trace amounts of four radioactive nuclides?carbon-14, cesium-137, cobalt-60, and iodine-129?were detected in the contaminated water stored in the tanks for the second discharge, but all were well below the official concentration limits.

TEPCO also announced that since the first discharge began on August 24, regular sampling and analysis of seawater and fish around the nuclear power plant have found no abnormalities in tritium concentrations.

TEPCO plans to discharge a total of 31,200 tons of contaminated water over four phases by March next year. During the first discharge, which started on August 24 and ended on the 11th of last month, 7,788 tons were released into the sea.

TEPCO estimates that it will take at least 30 years to completely discharge the contaminated water, but since the decommissioning schedule is uncertain, it is unknown when the actual discharge will end. The amount to be discharged after April next year has not yet been determined.