Cooling of No.4 reactor pool stopped

February 25, 2014

Reactor pool cooling system stopped

http://www3.nhk.or.jp/nhkworld/english/news/20140225_31.html

The operator of Fukushima Daiichi nuclear plant says the cooling system for the spent fuel pool at the No.4 reactor stopped temporarily due to an accident.

Tokyo Electric Power Company, or TEPCO, says a short-circuit alarm went off at around 9:40 AM on Tuesday, and a part of the reactor pool cooling system lost power.

TEPCO says drilling work on a road south of the reactor damaged a power cable. Cooling resumed around 4 and half hours later after personnel switched the system to another power source.

The spent fuel pool was 13 degrees Celsius when the cooling system stopped. The utility says the temperature rose only slightly, and did not surpass the company's safety limit of 65 degrees.

Workers suspended removing spent nuclear fuel from the No.4 reactor pool due the power outage, but resumed shortly after 2:30 PM.

Feb. 25, 2014 - Updated 06:46 UTC

Fukushima No.4 reactor pool's cooling fan halts

http://www3.nhk.or.jp/nhkworld/english/news/20140225_19.html

The operator of the Fukushima Daiichi nuclear power plant says a cooling fan for the spent fuel pool at the No. 4 reactor has stopped working.

Tokyo Electric Power Company announced on Tuesday that a warning alarm for an electrical problem went off at 9:40 AM.

The firm says work to remove spent fuel from the pool has been suspended. But it says there are 2 cooling systems, so it will switch to the second one and cooling should resume by around 1 PM.

The pool temperature is now 13 degrees Celsius. TEPCO estimates that it will rise by about 0.3 degrees per hour.

The operator says a nearby electrical cable may have been damaged in excavation work. The company is looking into the cause of the fan failure.

Feb. 25, 2014 - Updated 02:39 UTC