TEPCO conducted a simulation to investigate the effects of exposure to treated water containing tritium, which continues to accumulate at the Fukushima Daiichi Nuclear Power Station, and announced the results on the 17th.
The impact is extremely minor.
TEPCO plans to release treated water containing radioactive substances such as tritium, which remains after treating the contaminated water from the Fukushima Daiichi Nuclear Power Plant, into the sea through a submarine tunnel about 1 km offshore from the nuclear power plant.
To that end, TEPCO conducted a simulation to investigate the effects of radiation exposure when released into the sea.
In the simulation, based on the data of radioactive materials contained in the actual tank, the concentration of tritium is diluted to less than 1500 becquerels per liter, which is 1/40 of the national standard, and then annually. The total amount released is set at 22 trillion becquerels, which is the same as the target before the accident.
As a result, the range where the concentration of tritium in seawater is more than 1 becquerel per liter, which is higher than the current concentration in seawater, is only in the range of 2 to 3 km around the nuclear power plant.
In addition, there was a place of about 30 becquerels per liter near the exit of the undersea tunnel, but the concentration decreased rapidly as it spread to the surrounding area.
Based on this result, we calculated the annual exposure dose of fishermen living along the coast, and found that the average intake of marine products is 60,000 minutes of 1 millisievert, which is considered to be acceptable for one year. It means that it has decreased from 1 to 1 / 10,000.
In addition, even if it is assumed that the radioactive substances other than tritium contained in the treated water, which do not actually exist, are only those of a type that has a relatively large effect of exposure, the exposure dose is 2000 minutes of 1 millisievert. The impact is extremely minor, according to TEPCO.