September leak at Oarai research center explained

 December 26, 2014

Cause of radioactive water leak determined

http://www3.nhk.or.jp/nhkworld/english/news/20141226_18.html

Dec. 26, 2014 - Updated 05:26 UTC+1

A Japanese nuclear research organization says a spill of low-level radioactive water at its facility was caused by a mistakenly loosened pipe valve.

The incident took place at the Japan Atomic Energy Agency's Oarai research center, northeast of Tokyo, on September 11th.

Researchers at the facility found a pool of water in the basement of a building next to the structure housing a research reactor. The water contained a small amount of radioactive substances.

Agency officials told reporters on Thursday that the water had come from a pool that contains spent nuclear fuel.

They said a valve on a pipe connecting the pool with a tank of resin coolant in the basement of the building had become loose, allowing water to flow into the tank and spill out.

They said the valve may have been inadvertently loosened 2 years ago by workers during repairs to the building's floor, which was damaged in the massive earthquake in March of 2011.

The deputy head of the Oarai research center said that officials failed to make thorough safety checks because the reactor's operation has been halted.

He said the staff had learned a lesson from the incident and will try to prevent a recurrence.