Human Error Stopped Reactor 3 Cooling System

Cooling water briefly stopped at Fukushima plant

Injections of water to cool melted fuel in a reactor at the Fukushima Daiichi nuclear power plant stopped briefly due to human error on Monday.
The plant’s operator, Tokyo Electric Power Company, says an alarm system was activated at around 10 AM when a water pump at the No. 3 reactor shut down.
An internal investigation by the utility found that a worker had mistakenly hit the pump’s switch with his elbow while checking instruments. TEPCO resumed the water injections using a different pump about 1 hour later.
The utility notified local prefectural authorities and nearby areas of the problem just one minute before it resumed the water injections.
TEPCO officials say they detected no changes in the temperature at the bottom of the reactor or in radiation levels at monitoring posts around the plant.
Also on Sunday night, cooling operations temporarily stopped in the spent nuclear fuel pool at the plant’s numbers 1, 2 and 3 reactors when some valves inexplicably opened.
TEPCO says it takes these human errors seriously and will do it best to prevent recurrences.

http://www3.nhk.or.jp/nhkworld/en/news/20161205_27/

Fukushima reactor briefly loses cooling during inspection

One of the melted reactors at tsunami-hit Fukushima nuclear power plant had a temporary loss of cooling when a worker accidentally bumped a switch while passing through a narrow aisle of switch panels during an inspection and turned off the pumping system.

The plant operator, Tokyo Electric Power Co., said cooling for the No. 3 reactor, one of the three reactors that melted following the 2011 earthquake and tsunami, was out for nearly one hour Monday until a backup pump kicked in.

TEPCO said the reactor had enough water left inside and there was no temperature increase or radiation leak from the incident.

TEPCO acknowledged some other key switches are in similarly tight locations.

http://www.asahi.com/ajw/articles/AJ201612050069.html

December 6, 2016 - Posted by dunrenard | Fukushima 2016 | Cooling System, Fukushima Daiichi, Reactor 3