October 7, 2016

Radioactive water leaks from storage tank at Fukushima plant

http://www.asahi.com/ajw/articles/AJ201610070036.html

THE ASAHI SHIMBUN

Up to 32 liters of radioactive water leaked from a storage tank at the crippled Fukushima No. 1 nuclear plant, but the contaminated liquid has been contained, Tokyo Electric Power Co. said Oct. 6.

The leaked water is currently within barriers surrounding the tank that are designed to block the flow of fluids, TEPCO, the plant’s operator, said.

The liquid contained water that had been treated to remove radioactive strontium and other substances, as well as highly contaminated water from the bottom of the tank that was stored shortly after the nuclear accident started in 2011.

A radioactivity level of 590,000 becquerels of beta ray-emitting materials was detected per liter of the leaked water.

The water seeped out of a tank with bolted seams on its sides, which are more prone to leaks than those with welded walls.

TEPCO continues to use the bolted containers despite the risk because production of welded tanks cannot keep pace with the buildup of contaminated water, mainly from groundwater entering the damaged reactor buildings, at the nuclear plant.

Storage tank leaks at Fukushima Daiichi plant

http://www3.nhk.or.jp/nhkworld/en/news/20161007_02/

Workers at the crippled Fukushima Daiichi nuclear plant have found a leak of highly radioactive water from a waste water tank.

Its operator, Tokyo Electric Power Company, says the water likely leaked from a seam of the tank.

The leaked water was spotted on Wednesday on the side of one of an array of steel tanks holding contaminated water that is continuously generated at the site.

TEPCO's analysis found 590,000 becquerel per liter of beta-emitting radioactive materials in the water.

Tokyo Electric estimates that 32 liters of such highly radioactive water had trickled out, mixed with rainwater, and remained within a barrier around the tank.

Workers moved water in the tank to another one to lower the water level enough to halt the leak.

The leaking cylindrical tank is made by splicing steel plates with bolts. But they have had waste water leaks in the past from seams.

The operator has been replacing these leak-prone tanks with new seamless ones. But the increasing volume of waste water makes it difficult for the utility to completely do away with the old ones.