The emergency cooling system of a reactor at the Kashiwazaki-Kariwa nuclear power plant in Niigata Prefecture that has just been restarted experienced a temporary glitch Monday morning, but there was no hazard to the environment, Tokyo Electric Power Co. said.
The glitch was reported as Tepco activated the No. 7 reactor's core isolation cooling system as part of trial operations that started Saturday.
Tepco found the level of coolant in the pool had risen. After it was lowered, Tepco then found it was unable to shut down the cooling system, which pours coolant into the reactor in the event of an emergency, and eventually stopped it with another method.
The 1.356-million-kilowatt advanced boiling-water reactor, at the world's largest nuclear complex in terms of output, was restarted after the entire complex was halted by an earthquake in July 2007.