NHK...

The operator of the damaged nuclear plant in Fukushima has revised its plan to bring it under control.

Tokyo Electric Power Company announced the changes on Tuesday, one month after it released its original plan.

The original plan called for filling up Number 1, 2 and 3 reactors with water, but TEPCO says injected water may leak out under present conditions.

This is due to the recent discovery that fuel rods for the Number 1 reactor had melted, apparently damaging the vessel containing the reactor, and a large amount of water has been found to have leaked out of the vessel. The utility suspects that the Number 2 and 3 reactors are in a similar situation due to apparent meltdowns.

The company now says it will reduce the amount of radioactive materials in the water accumulated in the reactor and turbine buildings. Then it will circulate that water as coolant between the reactors and the turbine buildings. It also plans to install heat exchangers to cool spent-fuel storage pools at Number 1, 3 and 4 reactors by about July.

TEPCO also plans to set up a facility in the plant's compound probably, next month, to deal with contaminated water accumulated in the course of water injection into the reactors. Such water is estimated to total 200,000 tons within the year. TEPCO says the facility is designed to lower the radioactive density of contaminated water so it can be reused to cool the reactors, or be stored as relatively low-level radioactive water.

The utility also plans to build makeshift seawalls in the compound. It plans to consider engineering work to block radioactive materials from contaminating ground water.

The revised plan also calls for better conditions for workers at the plant, including more relaxation and sleeping rooms and improved meals.

Despite the revised plan, TEPCO is sticking to its schedule of achieving stable cooling by July and bringing about a cold shutdown of the reactors sometime between October and January.

Tuesday, May 17, 2011 22:05 +0900 (JST)