IAEA: Tepco Should Consider Controlled Discharge

Dec. 4, 2013 6:20 a.m. ETTOKYO—The International Atomic Energy Agency has advised the operator of the damaged Fukushima Daiichi nuclear-power plant to consider discharging lightly contaminated water into the ocean, as storing radioactive water at the plant has become increasingly unsustainable.

Juan Carlos Lentijo, head of an IAEA mission in Japan to monitor decommissioning work at the Fukushima Daiichi nuclear plant, accompanied by deputy leader Pil-Soo Hahn, right, speaks to the media in Tokyo. Agence France-Presse/Getty Images

The IAEA’s advice reflects the dilemma facing the plant’s operator, Tokyo Electric Power Co., which must weigh risks from the storage of increasing amounts of contaminated water against those of releasing some partially cleaned water into the ocean, a move vehemently opposed by local fishing communities and residents.

Groundwater flowing into the site and its reactors is continuously adding to about 400,000 tons of highly contaminated water stored in roughly 1,000 tanks at the site. Tepco said earlier this year that it had found contaminated water leaking from underground storage tanks. In addition to the leaks, concerns have also grown that the tanks will obstruct other work necessary to decommission the plant, which suffered multiple meltdowns after the March 2011 earthquake and tsunami.
Juan Carlos Lentijo, head of an IAEA mission in Japan to monitor the decommissioning work, said at a Tokyo news conference Wednesday that Tepco should weigh the possible discharge against the total risks involved in the work, adding, “Controlled discharge is practiced in nuclear facilities across the world.”
Every day, 400 metric tons of highly contaminated water is produced at the site. Radioactive materials can be removed from the water by a system known as ALPS, but relatively less harmful tritium remains.
On Tuesday, a government-appointed expert panel said in a draft of Japan’s new Fukushima water-containment plan that most of the highly contaminated water will be cleansed by ALPS in about seven years, but the amount of water containing tritium will keep rising, exceeding 700,000 tons in two years.
Shunichi Tanaka, chairman of Japan’s Nuclear Regulation Authority, said on Wednesday in a separate news conference that keeping all low-level contaminated water at the site would create a huge obstacle for other decommissioning work, including the use of remote-controlled machines to remove melted fuel at some of the reactors where radiation levels are very high.
“You cannot keep storing the water forever. We have to make choice comparing all risks involved,” Mr. Tanaka told reporters.
Tritium is a radioactive form of hydrogen with a half-life of about 12 years. It occurs naturally and is produced in the process of nuclear fission. Since it is a form of hydrogen, one of the elements in water, it is considered virtually impossible to separate out.
At the same time, tritium is seen as less harmful than other radioactive elements associated with nuclear plants. The U.S. Environmental Protection Agency calls it “one of the least dangerous of radionuclides.”
However, the presence of tritium has raised concerns among local fishermen that dumping the water into the ocean would put a stigma over their catch for years to come.
The IAEA mission said in a statement that any discharge should comply with safety guidelines, and Tepco should submit assessments of the safety and environmental impact for regulatory review before any discharge.
Write to Mari Iwata at mari.iwata@wsj.com

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