22 Mar (NucNet): Japan's Nuclear Regulation Authority (NRA) has told the International Atomic Energy Agency (IAEA) that cooling systems at all spent fuel pools at the Fukushima-Daiichi nuclear power plant have resumed operation.
This follows a power outage that began at 18:57 local time on 18 March 2013, disabling spent fuel cooling systems at units 1, 3, and 4 and the common spent fuel pool.
In a separate statement, plant operator Tokyo Electric Power Company (Tepco) said all of the systems affected by the loss of power had been restarted.
Tepco said the problem had been caused by a loss of electric power at the plant’s main emergency centre.
According to the IAEA, the NRA said the cooling system at Unit 3 was restored at 22:43 local time on 19 March, and at the common spent-fuel pool at 00:12 on 20 March. The systems at Unit 1 and Unit 4 were restarted earlier on 19 March.
Tepco said it was continuing to investigate the cause of the power outage.
The company also confirmed there had been no significant impact on the temperature of water in the fuel pools and temperatures had not approached the “operational limit” of 65 degrees Celsius.
This limit is a threshold for taking additional cooling measures and not the temperature at which damage to the fuel occurs. The risk of damage would begin to rise only when the temperature of the pool water approached boiling point.
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