43 condenser pipes damaged at Shizuoka nuke plant

Kyodo

Chubu Electric Power Co. said Friday that 43 pipes in a turbine steam condenser were found to be damaged at the Hamaoka nuclear plant in Shizuoka Prefecture, after the utility last month probed the leak of seawater into a reactor at the plant.

Two other pipes were found to be deformed, the utility added, without elaborating.

On May 14, some 5 tons of seawater entered the No. 5 reactor at the plant in the city of Omaezaki, following the discovery of around 400 tons of seawater in the condenser, which cools steam from the turbine and turns it into water.

The trouble occurred during work to put the reactor into a state of cold shutdown, according to Chubu Electric. At that time, about 530 tons of water were flowing per hour through the recirculation pipe for adjusting the water volume inside the reactor.

While there are some 21,000 pipes measuring 3 cm in diameter installed inside the condenser, the metal lid for the recirculation pipe was found to have fallen approximately 90 cm from the damaged pipes. The lid is about 20 cm across and weighs 3.5 kg.

As the recirculation pipe had a fracture on its welded part near the lid, water that gushed out of it possibly damaged the pipes, the utility said.