Tokyo Electric Power Company (Tepco) has begun a gradual process to bring the first reactor unit at the Kashiwazaki Kariwa nuclear power plant back into operation.
Along with the seven other reactors at the plant, unit 1 was subject to the powerful Niigata-Chuetsu offshore earthquake of July 2007 and suffered widespread minor damage. Unit 1, a 1067 MWe boiling water reactor, was offline for scheduled maintenance when the earthquake hit.
After lengthy inspection and repair Tepco began test operations on 21 May but stopped when a technical issue came to light concerning a pump on a water feed line to the reactor. Having put this right, the process to start up again began on 31 May.
First in a series of tests will be a trial at a pressure of 3.5 MPa before another at 7 MPa. Later will be a start up to 20% power and shutdown followed by a gradual increase to power generation. Around that point the reactor could be described as back in commercial operation.
Unit 1 is the third of the power plant's reactors to be brought back into service. Unit 7 resumed commercial operation in May 2009, followed by its identical twin unit 6 in January this year.
Researched and written
by World Nuclear News