When a partial power outage caused the cooling system at the Fukushima Daiichi Nuclear Power Station to fail earlier this week, concerns were renewed as to the vulnerability of the now infamous power plant. The site of a triple meltdown following Japan’s earthquake and tsunami in 2011, the plant lost cooling facilities for as long as 30 hours beginning on Monday. As Tokyo Electric Power Company (Tepco) successfully brought the cooling systems back online they found what they believe to have been the source of the panic-raising outage: the charred remains of a rat.

Fukushima, Fukushima Daiichi, Nuclear Power, Tepco, Cooling Systems, Spent Fuel, Radioactive

The rodent appears to have brought down Fukushima Daiichi’s vital cooling system in much the same way as small critters tend to wreak havoc on pretty much anything important; with its teeth. According to the New York Times, when Tepco’s engineers “looked inside a faulty switchboard, they found burn marks and the rodent’s scorched body. The company said it appeared that the rat had somehow short-circuited the switchboard, possibly by gnawing on cables.”

Perhaps more troubling, it appears that Tepco had not taken steps to prevent such an incident from occurring. The Japan Times reports “Tepco said it had not taken any steps to prevent wildlife, such as rodents, from getting at the switchboard” which “was located on the back of a truck that had been parked outside since May 2011.” The utility company has been dependent on makeshift cooling systems since 2011, when the devastation from the earthquake and tsunami caused, among other things, the pools to overheat. Tepco is reportedly been planning to transition to a permanent switchboard by the end of the month.

Tepco was quick to emphasize that at no point was the nuclear power station at immediate risk of a second catastrophe, explaining in a press release “[s]ince it takes a certain amount of time for the spent fuel pool/common pool water temperatures to increase, the temperatures will not immediately reach the maximum allowed temperature.” The impacted pools is stored—would have taken between four and 26 days to reach 65 degrees—the temperature at which the spent fuel rods stored in the pools could potentially overheat and catch fire, releasing radioactive materials.

While there has been no lasting harm from this outage, it does continue to raise significant questions as to the vulnerability of the Fukushima Daiichi plant, and is likely to do little to imbue confidence in plans to restart many of Japan’s nuclear reactors that were shut down in the months following the earthquake.

Via The New York Times