TOKYO, August 28. /TASS/. Water being released into the Pacific Ocean from Japan’s Fukushima Nuclear Power Plant (NPP) is undergoing three-stage tests for radioactive substances, the Sankei Shimbun newspaper writes.

First, tests are carried out at a purification facility for water used to cool the three nuclear reactors damaged by a tsunami in the spring of 2011. The tests must show that the liquid does not contain any radioactive substances other than tritium, a radioactive isotope of hydrogen. After that, the purified water is pumped into one of roughly 1,000 steel tanks accumulated at the nuclear facility.

Before being released into the ocean, the water is once again tested for the absence of 69 types of radioactive substances, including cesium-137 and uranium-234. The water is then diluted at a ratio of 1,200 metric tons of clean sea water to one ton of purified water, which is expected to reduce the concentration of tritium to a level 952 times below the acceptable limits established by the International Commission on Radiological Protection and the Japanese government. Experts from the International Atomic Energy Agency (IAEA) and the South Korean government are participating in collecting water samples.

Once the third test for tritium is completed, authorization is given to release the water into the ocean. Nine-member teams monitor and lead the process around the clock. They are also capable of monitoring tritium levels.

Water samples are collected in ten locations three kilometers from the place of discharge. No traces of tritium have been found there so far, nor have any been found in the samples of fish examined by experts from the Japanese Fisheries Agency.

As much as 31.2 metric tons of wastewater are expected to be released into the ocean in the 2023 fiscal year (ending on March 31, 2024). About 1.34 mln tons of water is stored in tanks at the NPP. Altogether, the water purification and discharge process is expected to take about 30 years.