Nuclear crisis alarms US

TOKYO—Amid widening alarm in the United States and elsewhere about Japan’s nuclear crisis, Japanese authorities reached for ever more desperate and unconventional methods on Thursday to cool stricken reactors, deploying helicopters and water cannons in a race to prevent perilous overheating in spent fuel rods.

The measures came a day after the chair of the US Nuclear Regulatory Commission gave a far bleaker appraisal of the threat posed by the nuclear crisis than the Japanese government had offered. He said radiation at the Fukushima Dai-ichi Nuclear Power Station had spiked to “extremely high” levels.

But Japanese officials on Thursday played down the concerns of Gregory Jaczko, the chair of the US commission, who asserted that the nuclear crisis had worsened to the point that emergency workers would find it difficult to fix the problem.

In his testimony before the US Congress on Wednesday, Jaczko (pronounced YAZZ-koe) said American officials believed that the damage to at least one crippled reactor was much more serious than Tokyo had acknowledged.

Agonizing choice

Jaczko’s testimony, the most extended comments by a senior US official on Japan’s nuclear disaster, described what amounts to an agonizing choice for Japanese authorities: keep sending workers into an increasingly contaminated area in a last-ditch effort to cover nuclear fuel with water, or do more to protect the workers but risk letting the pools boil away—and thus risk a broader meltdown.

Jaczko advised Americans to stay much farther away from the Dai-ichi plant than the perimeter established by Japanese authorities.

Jaczko’s announcement opened a new and ominous chapter in the six-day-long effort by Japanese engineers to bring six side-by-side nuclear reactors under control after their cooling systems were knocked out by an earthquake and a tsunami last Friday.

Ineffective

On the ground and in the air around the stricken Dai-ichi plant, 220 kilometers northeast of Tokyo, Japan’s Self-Defense Forces dumped water from a helicopter on the No. 3 reactor on Thursday morning, making several passes as a plume of white smoke billowed.

But the measure—more often used to tamp down forest fires—seemed to prove ineffective because the water was blown off target.

Military fire trucks also sprayed cooling water on spent fuel rods, the NHK broadcaster said.

Moments earlier, police in water cannon trucks, attempting to get within 50 meters of the No. 3 reactor, had been forced back by high levels of radiation in the same area.

Tokyo Electric Power Co., which operates the reactors, was also working to complete a high power line to the plant to restore the electricity needed to run the cooling systems.

Both the Self-Defense Forces and the Tokyo Metropolitan Police planned to deploy water cannons at the No. 3 reactor on Thursday, hoping to deliver some 42 tons of water—eight tons less than the government had said earlier that the unit needed on a typical day to keep spent fuel rods from overheating.

Most startling

Jaczko’s most startling assertion was that there was now little or no water in the pool storing spent nuclear fuel at the No. 4 reactor of the Dai-ichi nuclear plant, leaving fuel rods stored there exposed and bleeding radiation into the atmosphere.

As a result, he said, “We believe that radiation levels are extremely high, which could possibly impact the ability to take corrective measures.”

His statement was quickly but not definitively rebutted by officials of Tokyo Electric.

“We can’t get inside to check, but we’ve been carefully watching the building’s environs, and there has not been any particular problem,” Hajime Motojuku, a spokesperson for Tokyo Electric, said on Thursday morning in Japan.

Later Thursday, a spokesperson for Japan’s Nuclear and Industrial Safety Agency, Yoshitaka Nagayama, was more equivocal. “Because we have been unable to go to the scene, we cannot confirm whether there is water left or not in the spent fuel pool at Reactor No. 4,” he said.

Japanese officials, however, raised concerns about the No. 5 and No. 6 reactors where spent rods were stored, saying they had experienced a slight rise in temperature.

At least three reactors of the Dai-ichi plant were in active use before the quake, and three others were inactive but had storage pools for spent fuel.

Reactor pool empty

On Wednesday night, Jaczko reiterated his earlier statement and added that US commission representatives in Tokyo had confirmed that the pool at the No. 4 reactor was empty. This, he said, had been confirmed by Tokyo Electric and other Japanese officials.
Jaczko also stressed that high radiation fields were going to make it very difficult to continue having people work at the plant where the crippled reactor needed to remain covered with water at all times.

If the American analysis is accurate and emergency crews at the plant have been unable to keep the spent fuel at that inoperative reactor properly cooled, radiation levels would make it doubly hard in fixing the problem at the No. 4 reactor and servicing the other troubled reactors.

In the worst case, experts say, emergency workers would be forced to vacate the plant altogether, and the fuel rods in reactors and spent fuel pools would be left to melt down, leading to much larger releases of radioactive materials.

While radiation levels at the plant have varied tremendously, Jaczko said that the peak levels reported there “would be lethal within a fairly short period of time.”

He added that another spent fuel pool at the No. 3 reactor might also be losing water and could soon be in the same condition.

80-km radius, not just 20

On Wednesday, the US Embassy in Tokyo, on advice from the Nuclear Regulatory Commission, told Americans to evacuate a radius of “approximately 50 miles”—about 80 kilometers—from the Fukushima plant.

The advice to Americans in Japan represents a graver assessment of the risk in the immediate vicinity of the Dai-ichi plant than the warnings made by the Japanese themselves, who have told everyone within 20 kilometers to evacuate, and those within 20 to 30 kilometers to take shelter.

“We would recommend an evacuation to a much larger radius than has currently been provided by Japan,” Jaczko said.

That assessment seems bound to embarrass, if not anger, Japanese officials, suggesting they have miscalculated the danger or deliberately played down the risks.

Frozen leadership

It was not immediately clear how many people live within the zone around the plant that US officials believed should be evacuated. But the zone gets far closer to the city of Sendai, with its population of one million, which took the brunt of the earthquake last week.

US officials who have been dealing with their Japanese counterparts report that the country’s political and bureaucratic leadership has appeared frozen in place, unwilling to communicate clearly about the problem’s scope and, in some cases, unwilling to accept outside assistance.

Two US officials said they believed that the Japanese government itself was not getting a clear picture from Tokyo Electric.

“Everything in their system is built to build consensus slowly,” said one American official who would not be quoted by name because of the delicacy of discussions with Japan. “And everything in this crisis is about moving quickly. It’s not working.”

More dangerous

Though the Dai-ichi plant’s reactors shut down automatically when the quake struck on Friday, the subsequent tsunami wiped out the backup electronic pumping and cooling system necessary to keep the fuel rods in the reactors and the storage pools for spent nuclear fuel covered with cool water.

The spent fuel pools can be even more dangerous than the active fuel rods, as they are not contained in thick steel containers like the reactor core.

As they are exposed to air, the zirconium metal cladding on the rods can catch fire, and a deadly mix of radioactive elements can spew into the atmosphere. The most concern surrounds Cesium-137, which has a half-life of 30 years and can get into food supplies or be inhaled.

‘Backup backup’

Jaczko said radiation levels might make it impossible to continue what he called the “backup backup” cooling functions that have so far helped check the fuel melting inside the reactors.

Those efforts consist of using fire hoses to dump water on overheated fuel and then letting the radioactive steam vent into the atmosphere.

Those emergency measures, carried out by a small squad of workers and firefighters, represent Japan’s central effort to forestall a full-blown fuel meltdown that would lead to much higher releases of radioactive material into the air.

Experts say workers at the plant probably could not approach a fuel pool that was dry, because radiation levels would be too high.

In a normally operating pool, the water not only provides cooling but also shields workers from gamma radiation. New York Times News Service