Why Japan Is Dumping Water From Fukushima Into the Sea

The Japanese utility giant Tepco is planning to release more than 1 million cubic meters of treated radioactive water -- enough to fill 500 Olympic-size swimming pools -- from the wrecked Fukushima Dai-Ichi nuclear power plant into the Pacific Ocean, part of its nearly $200 billion effort to clean up the worst atomic accident since Chernobyl. Storage tanks at the site are forecast to be full as early as mid-2022, and space for building more is scarce. Scary as it sounds, discharges are common practice in the industry and would likely meet global guidelines. That hasn’t assuaged angry locals or neighboring China and South Korea.

A 2011 earthquake, the strongest ever recorded in Japan, and ensuing tsunami caused structural damage to Fukushima’s reactor buildings, about 220 kilometers (137 miles) north of Tokyo. While Tepco cycles in water to keep fuel and debris cool, roughly 140 cubic meters of water becomes contaminated daily, including groundwater and rain. The tainted water is pumped out and run through something called the Advanced Liquid Processing System, or ALPS, then stored in one of roughly 1,000 tanks at the site. The processing removes most of the radioactive elements except for tritium.