Earthquake reactor returns

26 August 2009

Another reactor is repaired and returning to service after the earthquake that shut down all seven at Kashiwazaki Kariwa two years ago.


Kashiwazaki - IAEA mission
Experts from the International Atomic
Energy Agency are present while Tepco
inspects a steam turbine at
Kashiwazaki Kariwa (Image: IAEA)
After gaining approvals from the governor of Niigata prefecture, the mayor of Kashiwazaki and the village chief of Kariwa - as well as the Nuclear Industrial Safety Authority - Tokyo Electric Power Co restarted Kashiwazaki Kariwa 6 at 2.31pm local time today.


The reactor is being operated at low power in order to make functional tests of every single one of its systems. The test program will include a practice emergency shutdown, but given successful results the reactor is expected to soon be increasing power and returning to commercial operation.


The 1315 MWe Advanced Boiling Water Reactor will join its identical neighbour unit 7 in operation while Tepco continue to work on the other five reactors at the huge power plant. Unit 7 returned in early May this year, but Tepco has never announced a draft schedule for all the returns. In the meantime, the utility has suffered enormous bills for replacement power and fuel as well as geologic surveys, engineering and construction..


At the time the Niigata-Chuetsu-Oki earthquake struck, three of the reactors were already shut down for maintenance while the three in operation shut down automatically as did one that was in the process of starting up. All of them remained in a safe state throughout the 6.8 magnitude earthquake, but there was widespread minor damage which necessitated absolutely exhaustive checks and many repairs. Some mildly radioactive cooling water was shaken from pools, many barrels of low-level waste were knocked over and an external transformer failed and caught fire. The site grounds also suffered, with widespread soil liquefaction and structural damage to office buildings.