http://www.nytimes.com/2011/04/13/world/asia/13safety.html?partner=rss&emc=rss The condition of the damaged Fukushima Daiichi reactors in Japan is “static,” but with improvised cooling efforts they are “not stable,” the chairman of the Nuclear Regulatory Commission told a Senate committee on Tuesday.
Enlarge This Image
“We don’t see significant changes from day to day,” the chairman, Gregory B. Jaczko, said, while adding that the risk of big additional releases gets smaller as each day passes.
Long-term regular cooling of the reactors has not been re-established, nor has a regular way of delivering water to the spent-fuel pools, he told the Senate Environment and Public Works Committee. And when an aftershock hit the site and cut some offshore power supplies, he said, some pumps failed and cooling stopped for 50 minutes.
The situation is “not stable” and will remain so until “that kind of situation would be handled in a predictable manner,” he said. Mr. Jaczko also offered a new theory about the cause of the explosions that destroyed the secondary containment structures of several of the reactors. The prevailing theory has been that hydrogen gas was created when the reactor cores overheated and filled with steam instead of water; the steam reacts with the metal, which turns into a powder and then gives off hydrogen.
<more>