Japanese nuclear reactors in peril, radiation surges after earthquake, tsunami

By Steven Mufson
Washington Post Staff Writer
Saturday, March 12, 2011; A01

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."

Meanwhile, Tokyo Electric said it had decided to vent slightly radioactive steam and gas to relieve pressure that had increased sharply in the containment building at unit No. 1. The company said on its Web site that the increase was "assumed to be due to leakage of reactor coolant." It remained unclear where the leak was. The company said it did not think there was leakage of reactor coolant in the containment vessel "at this moment."

The purpose of a containment building, which surrounds the reactor core, is to contain unplanned releases of steam or gases from the core. If there is not enough water in the reactor core, water turns to steam and is released through special valves into the containment building, nuclear experts said. That could cause an increase in pressure inside the sealed containment building and ultimately force a release of gas and steam through filters meant to keep most, though not all, of the radiation inside the building.

There were also reports of elevated radiation levels inside the control room of that reactor unit, which was built 40 years ago by General Electric. NISA said levels were 1,000 times the norm . The Associated Press later quoted an official from NISA as saying that a measurement of radiation levels outside the plant was eight times as high as normal. Even that level of radiation still posed little danger to residents, nuclear experts said. They also said the release of steam and gas from containment buildings posed little danger.

The status of Tokyo Electric's Daina plants remained unclear. Earlier, they had been said to have completed automatic shutdowns. But Saturday, Tokyo Electric suggested that they were having problems similar to the ones at the other nuclear complex because of disruptions in the power supply needed to run cooling facilities.

"The danger is the very thermally hot reactor cores at the plant must be continuously cooled for 24 to 48 hours," said Kevin Kamps, a specialist in nuclear waste at Beyond Nuclear, a group devoted to highlighting the perils of nuclear power. "Without any electricity, the pumps won't be able to pump water through the hot reactor cores to cool them."

In addition to the efforts to get Tokyo Electric's nuclear reactors under control, Japan's NISA said Friday that a fire had broken out at the Onagawa nuclear power plant but was later extinguished. The three reactors at the Onagawa site remained closed.

Staff writer Mary Beth Sheridan contributed to this report.

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