information about Fukushima published in English in Japanese media info publiée en anglais dans la presse japonaise
20 Mars 2013
March 20, 2013
at-zap: A dead rat lies near a switchboard Wednesday at the Fukushima No. 1 nuclear plant. Tokyo Electric Power Co. suspects the rodent caused the Monday short-circuit that disabled the cooling systems for the fuel pools of the plant's stricken reactors. | TOKYO ELECTRIC POWER CO./KYODO
Kyodo
A rat apparently gnawed on a switchboard or its wiring, causing the 30-hour power cutoff for the spent-fuel pool cooling systems at the triple-meltdown-hit Fukushima No. 1 nuclear plant that led to renewed fallout fears, Tokyo Electric Power Co. indicated Wednesday.
Tepco said it found the burnt carcass of what appeared to be a rat near the makeshift switchboard as well as burn marks on the equipment, although it has yet to determine the exact cause of the power outage.
The switchboard runs the cooling systems of the spent-fuel pools of reactors 3 and 4 as well as a common pool located inside another building at the site that contains 6,377 nuclear fuel assemblies.
Tepco said it had not taken any steps to prevent wildlife, such as rodents, from getting at the switchboard and said it is continuing to investigate other factors that may have caused the power outrage, which was apparently resolved minutes after midnight Tuesday.
The makeshift switchboard was located on the back of a truck that had been parked outside since May 2011. Tepco was planning to stop using the equipment and switch to a new permanent switchboard by the end of this month.
The cooling system for reactor 1 has a separate electrical system from the makeshift power switchboard, but at the time of the power outrage it was connected to the makeshift switchboard due to ongoing multiple tasks and was affected, the utility said.
Tepco restarted all nine power outage-hit facilities, including an installation to remove radioactive substances from water used to cool the crippled reactors, by midnight Tuesday after electricity went out a day earlier.
On Wednesday, the water temperature stood at 31.8 degrees in the common pool that stores the 6,377 fuel assemblies, 31 degrees in the reactor 4 spent-fuel pool and 17 degrees in both the reactors 1 and 3 fuel pools.
Those temperatures are between 1 and 6.3 degrees higher than the levels before the power outage.
Tepco spokesman Masayuki Ono said, “It will take several days for the temperatures to get back to normal.”
The latest trouble occurred more than two years after the plant was ravaged by the tsunami from the March 11, 2011, Great East Japan Earthquake, as well as possibly by the temblor itself. Reactors 1-3 suffered core meltdowns after the disaster struck, as well as hydrogen explosions, which destroyed the building housing reactor 4 and left its spent-fuel pool exposed.
March 20, 2013
Switchboard found burnt at Fukushima plant
http://www3.nhk.or.jp/daily/english/20130320_28.html
Tokyo Electric Power Company says it has found burn marks on one of the power distribution boards that stopped working and brought to a halt cooling systems for spent-fuel pools at the damaged Fukushima Daiichi nuclear plant.
A small animal that appeared to be a rat was also found dead near the board. The company suspects the animal touched the terminal of the board and caused a short circuit.
The cooling systems were restored after midnight on Wednesday after a suspension of about 29 hours.
TEPCO started investigating the cause of the trouble on Wednesday morning and closely checked the 3 boards.
Shortly after noon, workers found burn marks on an electric terminal of one of the boards and a nearby wall. The board was installed on a truck after the nuclear accident.
The workers also found the body of a small animal about 15 centimeters long nearby.
The company suspects the animal touched the terminal and triggered a short circuit, leading to a major problem after other power-supply facilities detected abnormalities and came to a halt.
The latest interruption to the cooling system was the longest since the nuclear meltdown following the March 2011 quake and tsunami.
A brief power failure caused 9 systems to fail, including the cooling systems for the spent fuel pools of the No. 1, 3 and 4 reactors, and a shared pool in the plant's compound, on Monday evening.
Mar. 20, 2013 - Updated 14:57 UTC (23:57 JST)
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