747 tons water leak

March 11, 2015

Another contaminated water leak found at Fukushima nuke plant

http://mainichi.jp/english/english/newsselect/news/20150311p2a00m0na003000c.html

Some 747 metric tons of contaminated rainwater has leaked from a water storage tank area at the Fukushima No. 1 nuclear plant, Tokyo Electric Power Co. announced on March 10.

According to the plant operator, there are two layers of barriers around the groups of storage tanks built to hold radioactively contaminated water generated at the shattered nuclear station. The problem was first detected on the morning of March 10 by a TEPCO worker on a regular patrol around the storage tank group, who noticed the depth of rainwater collected between the outer and inner barriers had dropped by about 5 centimeters. The water valves in the outer barrier were closed, and the worker found two puddles forming outside the perimeter.

TEPCO stated that analysis of water samples from five points between the inner and outer barriers found contamination of up to 8,300 becquerels of beta radiation-emitting material per liter. The utility said that the water that had leaked through the barriers -- likely through the tie holes in tarps that have been lashed together -- was being absorbed into the ground and was not flowing to the ocean. TEPCO also suggested that the base of the barriers could be damaged. The barriers range from 30 to 50 centimeters tall.

"There is no change in the water levels in the tanks, so this contaminated water leak is not from the tanks themselves," the TEPCO announcement stated.