Tepco Faces Decision to Dump Radioactive Water in Pacific

By Tsuyoshi Inajima - Apr 12, 2013 3:17 AM GMT+0100

Tepco Faces Decision to Dump Radioactive Water in Pacific Ocean (bloomberg.com)

Tokyo Electric Power Co. (9501)’s discovery of leaks in water storage pits at the wrecked Fukushima atomic station raises the risk the utility will be forced to dump radioactive water in the Pacific Ocean.

Leaks were found in three of seven pits in the past week, reducing the options for moving contaminated water from basements of reactor buildings. Water in the basements is from the months after the earthquake and tsunami disabled the plant two years ago, when disaster teams used hose pipes and pumps to try and cool the reactors.
While the company has since built a makeshift sealed cooling system, underground water is breaching basement walls at a rate of about 400 tons a day and becoming contaminated, according to Tepco’s estimate. With Japan’s rainy season approaching, contaminated water levels are likely to increase at the plant 220 kilometers (137 miles) northeast of Tokyo.
Reducing radiation levels in the water and pouring it into the sea is one of two options the utility has, said Kazuhiko Kudo, a research professor of nuclear engineering at Kyushu University. The other option is “to keep building above-ground storage tanks,” said Kudo. That’s a fight Tepco can’t win without stopping the underground water pouring into the basements, Kudo said.
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On March 30, Tepco started test runs of equipment that the operator says can remove 62 kinds of radioactive substances. Still, the purification system called ALPS can’t remove tritium, a hydrogen isotope. The water processing system has also had problems and was temporarily halted last week because of incorrect operation.

Leaking Pits

Currently, about 280,000 tons of highly radioactive water is stored at the Fukushima plant, according to Tepco’s latest data. That’s enough to fill about 112 Olympic-sized swimming pools, according to Bloomberg News calculations.
To store the water, Tepco dug underground pits lined with three layers of waterproof sheet to prevent seepage into the surrounding soil, according to the utility.
The same method is used in industrial waste disposal, said Koji Kumagai, a geotechnical engineering professor at the Hachinohe Institute of Technology.
A design flaw is unlikely to have caused the leaks as the method is used around the world, Kumagai said in an phone interview. “The question is whether Tepco properly inspected equipment and carried out tests before pouring radioactive water into the pits.”
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