Factual background
April 14, 2021 Factual background, provided to complement Beyond Nuclear's press release re: the Japanese government's decision to dump 330 million gallons of highly radioactive wastewater into the Pacific Ocean at the Fukushima Daiichi Nuclear Power Plant site:
On April 13, 2021, the Japanese government announced its decision to intentionally discharge, directly into the Pacific Ocean, 1.25 million metric tons of radioactively contaminated wastewater accumulated over the past decade at the triple-reactor meltdown Fukushima Daiichi Nuclear Power Plant site. The dumping will begin in a couple of years, and continue for decades.
The 330 million U.S. gallons of radioactively contaminated wastewater is enough volume to fill 500 Olympic-sized swimming pools. It is currently contained in more than a thousand giant storage tanks across the site.
Tokyo Electric Power Company’s (TEPCO) latest publicly available data, from December 24, 2020, shows that even though the wastewater is run through the filters of the Advanced Liquid Processing System (ALPS) twice, radioactive tritium concentrations in the wastewater only decreased from 851,000 Becquerels*/liter (Bq/l) to 822,000 Bq/l. — still 13.7 times higher than Japan’s permissible or allowable standard for ocean dumping of tritium-contaminated water, which is 60,000 Bq/l.
Tritium has a 12.3 year half-life, which means 123 to 246 years of hazardous persistence.
The Fukushima wastewater is nearly one million times, or more, the concentration of natural tritium — caused by cosmic radiation’s interaction with the Earth’s atmosphere — in natural surface waters.
The first treatment by ALPS, TEPCO has admitted, also left 7 times the permissible concentration of hazardous Cesium-137 (a muscle-seeker), and around 2,155 times the permissible concentration of hazardous Strontium-90 (a bone-seeker), in the wastewater. Cs-137 and Sr-90 have around 30-year half-lives, meaning 300 to 600 years of hazardous persistence.
A single ALPS filtration, TEPCO’s data shows, also leaves 3 times the permissible level of hazardous Iodine-129 in the wastewater. I-129 has a half-life of 15.7 million years, so a hazardous persistence of 157 to 314 million years.
A single ALPS filtration, TEPCO’s data also shows, leaves 241 times the permissible level of another 55 radio-nuclides.
For these reasons, TEPCO plans to perform two ALPS filtration processes, to render non-tritium contaminants below permissible concentration levels for oceanic release. It also plans to water down the wastewater, to lower the concentration of tritium and non-tritium contaminants.
*A Becquerel is a unit of measure denoting one radioactive disintegration per second.