WASHINGTON — The chairman of the United States Nuclear Regulatory Commission gave a significantly bleaker appraisal of the threat posed by Japan’s nuclear crisis than the Japanese government, saying on Wednesday that the damage at one crippled reactor was much more serious than Japanese officials had acknowledged and advising Americans to evacuate a wider area around the plant than the perimeter established by Japan.
The announcement marked a new and ominous chapter in the five-day long effort by Japanese engineers to bring four 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 Tokyo, after American officials concluded that the Japanese warnings were insufficient, and that, deliberately or not, they had understated the potential threat of what is taking place inside the nuclear facility.
Gregory Jaczko, the chairman of the commission, said in Congressional testimony that the commission believed that all the water in the spent fuel pool at the No. 4 reactor of the Fukushima Daiichi Nuclear Power Station had boiled dry, leaving fuel rods stored there exposed and bleeding radiation. As a result, he said, “We believe that radiation levels are extremely high, which could possibly impact the ability to take corrective measures.”
On Thursday morning a spokesman for Tokyo Electric Power, the Daiichi plant operator, and a spokesman for Japan’s nuclear regulatory agency, denied Mr. Jaczko’s account, saying the situation at reactor No. 4 had not changed and that water remained in the spent fuel storage pool. But both officials said the situation was changing and that the reactor had not been inspected in recent hours.
http://www.nytimes.com/2011/03/17/world/asia/17nuclear.html?_r=1&hp