Nuclear plants imperiled
Japanese nuclear reactors in peril, radiation surges after earthquake, tsunami
Saturday, March 12, 2011
Japanese authorities declared a state of emergency Saturday for five nuclear reactors at two quake-stricken power plants as military and utility officials scrambled to tame rising pressure and radioactivity levels inside the units and stabilize the systems used to cool the plants' hot reactor cores.
Radiation surged to around 1,000 times the normal level in the control room of one reactor, Japan's Nuclear and Industrial Safety Agency (NISA) said. Meanwhile, Tokyo Electric Power Co. said Saturday that the temperatures at two other reactors at a different power plant were rising and that it had lost control over pressure in three reactors there.
Though no significant release of radioactive material had taken place, the earthquake, which forced the automatic shutdown of 11 of the country's 55 nuclear power plants, is certain to rattle confidence in nuclear power in Japan, where people have long been sensitized to the dangers of radioactive releases, and in the United States, where foes of nuclear power were already pointing to the Japan crisis as a warning sign.
The closure of the plants, representing nearly 20 percent of the country's capacity, also deals an economic blow to Japan, which relies on nuclear power for one-third of its electricity generation.
"It's a very serious situation for the reactors and might ultimately render those reactors unusable," said Howard Shaffer, a former Navy sub engineer and a member of the American Nuclear Society's public information committee.
Japanese authorities initially evacuated about 3,000 residents living within a 1.9-mile radius of the Fukushima Daiichi plant on the east coast about 200 miles north of Tokyo and south of the heavily damaged town of Sendai. Later they widened that evacuation to a six-mile radius. People within a 16.2-mile radius were told to remain indoors, said the Web site of the International Atomic Energy Agency's (IAEA) Incident and Emergency Center.
Tokyo Electric, which owns the Fukushima Daiichi complex, said later that it was also having trouble controlling three of the four reactors it owns at its nearby Fukushima Daina plant.
NISA said no dangerous radioactive material had been released, but the government evacuated people nonetheless.
The problems at the nuclear plants came in waves, starting with two of the six Daiichi units.
The quake disrupted the electric power the reactors use to run their cooling facilities, which pump water into the reactor core to cool the fuel rods there. The reactors switched to backup diesel generators, but the tsunami then swept in and shut down the generators used for the No. 2 reactor at Fukushima Daiichi. The unit then tapped excess steam in the core to power a turbine and switched to battery power, which would last only a few hours.
"There's a basic cooling system that requires power, which they don't have," said Glenn McCullough, former chairman of the Tennessee Valley Authority, who was tracking the Japan situation.
Japanese utility and government officials raced to get another generator to the site to prevent a possible partial meltdown. By Saturday morning they said they had succeeded. The utility said it had restored power from the grid, but the IAEA said power was restored from "mobile electricity supplies."