Tepco tackles rodent problems

05 April 2013

Tepco has now suffered two power supply problems at Fukushima Daiichi, both thanks - directly and indirectly - to small animals.  

Fukushima Daiichi animal screen (Tepco) 250x150  
Dead rat (Tepco) 250x105  
A newly installed mesh to prevent animal interference with switchgear; and the rodent guilty of causing the first outage (Images: Tepco)  

First was an outage that affected a large part of the site on 19 March. An investigation has concluded this was caused by a rodent which was able to get into a switchgear box after technical work left a small hole in plastic sheeting. The rat then walked across a circuit breaker, shorting the power supply. The power was restored after about five hours with the body of the animal quickly identified as the likely cause.

The latest event came at 2.00pm today, when power was cut to the used fuel pool for unit 3. Tepco said a fault probably occurred during work to install mesh barriers specifically to prevent any further animal access to electrical boxes.

At the time of today's power cut the pool temperature was 15.1ºC, said Tepco. The company checked the operational status of the secondary cooling system before starting it at 4.00pm, going on to return to the main system at 10.05pm. By then the pool temperature was 15.2ºC.

Three Tepco senior managers have been punished for a perceived slow response during the first power outage. Suffering a 5% pay cut this month are company president Naomi Hirose, executive vice president Zengo Aizawa and managing executive officer Akio Komori.

Researched and written
by World Nuclear News

Filed under: Japan, Fukushima accident