Temperatures rose unexpectedly in one of the reactors at the embattled Fukushima nuclear power plant this week. The Japanese utility Tepco injected the reactor with boric acid in an effort to prevent a nasty chain reaction.
Starting last Thursday, the temperature at a Fukushima facility reactor began rising steadily even though the whole nuclear power plant has been in a state of cold shutdown since December. A magnitude 9.0 earthquake and tsunami last March caused three of the plant's reactors to melt down, triggering large evacuations in the area.
On Monday, the temperature in Reactor Number 2 reached 158 degrees Fahrenheit, well up from where it was only a few days ago. The temperature should have been stable in the reactor, and the utility says it doesn't know why there's been a spike.
Operators at the plant responded by injecting boric acid into the reactor, according to Bloomberg's Tsuyoshi Inajima. Boric acid is used to capture radiation and help to prevent the radiation from leaking, a spokesman for Japan's nuclear safety agency told the Associated Press after the disaster in March.