When the 8.9 earthquake struck Japan earlier, its main effects were felt in an area northeast of Tokyo. The region is home to four major nuclear power plants, Onagawa, Fukushima I, Fukushima II, and Tokai. A total of eleven reactors at the three facilities shut down automatically when the quake struck. Three more units at Fukushima I were closed for maintenance at the time the ground started moving.
The first reported problem was a major fire in the diesel generator building at Onagawa. It took firefighters eight hours to extinguish the blaze. Japanese officials say that no radiation was released, and no evacuation was ordered.
Although all ten reactors at Fukushima I and II shut down, an operator at Fukushima I reported an “abnormality” during the procedure. We eventually learned that this was a loss of offsite power to the facility’s reactor cooling system. Operators were forced to rely on battery power to keep the pumps running.
The problem is that the batteries that provide emergency power to the cooling system only have a life of about eight hours. Fukushima scrambled to find replacement batteries, which were delivered by helicopter.
Compounding the battery problem was the discovery that a second facility, Onagawa, was also without offsite power and in need of backup batteries. Both facilities are also attempting to re-establish offsite power.
As a result of the cooling problem at Fukushima I, the Japanese Prime Minister declared a nuclear emergency, and ordered the evacuation of 5,800 people who live near the plant. There is no word yet whether there will be evacuations at Onagawa.
Later in the day, it was reported that there was a second fire, this one at Fukushima II. That one took two hours to put out.
The situation in Japan is understandably chaotic, and it may be a day or more before we know the full impact on the nuclear reactors that Japan relies on for 30 per cent of its electricity. What we do know is that the earthquake closed eleven plants that were responsible for 18 per cent of total electricity. Japan’s energy system was already saddled with the effects of a 2007 earthquake that knocked out the Kashiwazaki Kariwa complex for two years.
I’ll post more when the extent of the problem is better understood.