Michele Kearney's Nuclear Wire

Major Energy and Environmental News and Commentary affecting the Nuclear Industry.

Saturday, August 4, 2012

Hamaoka No. 5 seriously contaminated with seawater

Hamaoka No. 5 seriously contaminated with seawater

New interviews given by representatives of Chubu Electric Power Company and Japanese regulatory bodies now indicate that the previously announced seawater leakage into Hamaoka No. 5 and the resulting damage may be far worse than had previously been released or assumed.

On May 6, 2011, the Prime Minister requested that Chubu Electric shut down Hamaoka No. 4 and No. 5 reactors, which were operating at the time, due to seismic and tsunami considerations. Chubu agreed (and also agreed not to restart No. 3; the other two older plants are shut down permanently and decommissioning.)

During the May 14th shutdown of No. 5 plant, which is an ABWR type boiling water reactor rated 3926 MWt / 1325 MWe, there was a rupture of tubes in the plant's main condenser, which uses seawater on the secondary side. Chubu detected the seawater's ingress when conductivity measurements began to rise in the condenser and in the reactor. Following achievement of cold shutdown, Chubu entered the main condenser and discovered damaged tubes. Of course, Chubu had notified NISA immediately upon detection of the problem, and NISA has been involved ever since.

Chubu's investigation indicates that something over 400 cubic meters of seawater were added to the reactor system water inventory. A recent Reuters report is quoted as indicating about 5000 liters of seawater may have entered the reactor.

Seawater contamination in Hamaoka No. 5
 
 

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