本帖最后由 yukok 于 2011-3-18 01:35 编辑
U.S. Calls Radiation ‘Extremely High;’ Sees Japan Nuclear Crisis Worsening
http://www.nytimes.com/2011/03/17/world/asia/17nuclear.html?scp=1&sq=Gregory%20Jaczko,%20the%20chairman%20of%20the%20US%20Nuclear%20Regulatory%20Commission&st=cse
WASHINGTON — The chairman of the United States Nuclear Regulatory Commission gave a far bleaker appraisal on Wednesday of the threat posed by Japan’s nuclear crisis than the Japanese government had offered. He said American officials believed that the damage to at least one crippled reactor was much more serious than Tokyo had acknowledged, and he advised Americans to stay much farther away from the plant than the perimeter established by Japanese authorities.
The announcement opened 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 a 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 had received from Japan with data it had collected independently. Mr. 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 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 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,” Hajime Motojuku, a spokesman for Tokyo Electric, said Thursday morning in Japan. Later Thursday, a spokesman for Japan’s Nuclear and Industrial Safety Agency, Yoshitaka Nagayama, was more equivocal, saying, “Because we have been unable to go the scene, we cannot confirm whether there is water left or not in the spent fuel pool at Reactor No. 4.” At the same time, officials did raise concern about two other reactors where spent fuel rods were stored, Nos. 5 and 6, saying they had experienced a slight rise in temperature. On Wednesday night, Mr. Jaczko reiterated his earlier statement and added that commission representatives in Tokyo had confirmed that the pool at No. 4 was empty. He said Tokyo Electric and other officials in Japan had confirmed that, and also stressed that high radiation fields were 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 at the plant. In the worst case, experts say, workers could be forced to vacate the plant altogether, and the fuel rods in reactors and spent fuel pools would be left to meltdown, leading to much larger releases of radioactive materials. While radiation levels at the plant have varied tremendously, Mr. 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, might also be losing water and could soon be in the same condition. On Thursday morning, Japan’s Self-Defense Forces started dumping water from a helicopter on reactor No. 3, making several passes. They planned to do the same for No. 4 sometime Thursday. Tokyo Electric was also working busily to complete a high power line to the plant to restore the electricity needed to run the cooling systems, according to a senior nuclear industry executive.
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发表于 2011-3-18 01:34:12
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