Nuclear crisis worsening, US says
Radiation called ‘extremely high’; all work at plant could be halted
WASHINGTON — The chairman of the US Nuclear Regulatory Commission gave a far bleaker appraisal yesterday of the threat posed by Japan’s nuclear crisis than the Japanese government has offered, saying that American officials believe the damage to at least one crippled reactor was much more serious and advising Americans to stay much farther away from the plant than the perimeter established by Japanese authorities.
The announcement marked a new and ominous chapter in the five-day-long effort by Japanese engineers to bring the six side-by-side reactors under control after their cooling systems were knocked out by an earthquake and tsunami last Friday. It also suggested a serious split between Washington and its closest Asian ally at an especially delicate moment.
The congressional testimony by Gregory Jaczko, the chairman of the commission, was the first time the Obama administration had given its own assessment of the condition of the plant, apparently mixing information it has received from Japan with data it has collected independently.
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 Fukushima Daiichi Nuclear Power Station, leaving fuel rods 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 definitely rebutted by officials of Tokyo Electric Power, the Daiichi’s plant’s operator, and Japan’s nuclear regulatory agency.
“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,’’ said Hajime Motojuku, a spokesman for Tokyo Electric. Takumi Koyamada, a spokesman for the regulatory agency, said that as of 12 hours ago water remained in the spent fuel pool at reactor No. 4. “We cannot confirm that there has been a loss in water,’’ he said.
Last night, Jaczko reiterated his statement and added that commission representatives in Tokyo have confirmed that the pool is empty. He said Tokyo Electric and other officials in Japan have confirmed that and also stressed that high radiation fields are going to make it very difficult to continue having people work at the plant.
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 — it needs to remain covered with water at all times — radiation levels could make it difficult not only to fix the problem at reactor No. 4, but to keep servicing any of the other problem reactors.
In the worst case, specialists say, workers could 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 Reactor No. 3, may also be losing water and could soon be in the same condition.
Workers were ordered out of the plant yesterday, when radiation levels spiked. Japanese officials, however, said they have been sent in again as the levels subsided.
Helicopters began to drop buckets of water on the reactor, after days of delays over fears the helicopter crews would receive too large a dose of radiation.
Japanese utility officials raised hopes of easing the crisis by reporting they may be close to bringing power back to the plant and restoring the cooling systems.
Following Jaczko’s testimony yesterday and advice from the Nuclear Regulatory Commission, the US Embassy in Tokyo told Americans to evacuate a radius of “approximately 50 miles’’ from the Fukushima plant.
That advice represents a graver assessment of the risk in the immediate vicinity of Daiichi than the warnings made by the Japanese themselves, who have told everyone within 20 kilometers, about 12 miles, to evacuate, and those between 20 and 30 kilometers to take shelter.
That assessment seems bound to embarrass, if not anger, Japanese officials, suggesting that they miscalculated the danger or deliberately downplayed risks.
While maps of the plume of radiation being given off by the plant show that an elongated cloud will stretch across the Pacific, American officials said it would be so dissipated by the time it reached the West Coast of the United States it would not pose a health threat.
American officials were careful to offer no public comparisons to past nuclear accidents when discussing the Fukushima disaster. But clearly the crisis in Japan already far outstrips what happened at Three Mile Island in Pennsylvania, a single reactor where very little radiation escaped a crippled reactor. The effort now is to keep the Japanese crisis, involving at least three reactors that had been in active use before the quake, and three others that were inactive but had storage pools for spent fuel, from escalating to the levels of the worst nuclear disaster in history: Chernobyl.
Though the plant’s reactors shut down automatically when the earthquake struck, 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.
Jaczko said radiation levels may 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, implemented by a small squad of workers and firemen, represent Japan’s central effort to forestall a full-blown fuel meltdown.
At a hearing in Washington held by two subcommittees of the House Energy and Commerce Committee, Energy Secretary Steven Chu said, “We hear conflicting reports about exactly what is happening in the several reactors now at risk. I would not want to speculate.’’
Material from the Associated Press was used in this report.