REUTERS
2011/04/09
ROCKVILLE, Md.--Nuclear engineers on Thursday aggressively questioned the data and decisions behind the call from the U.S. nuclear regulator for a 50-mile evacuation zone around a failed Japanese nuclear plant.
The recommendation for U.S. citizens to leave that zone -- far larger than the 12-mile evacuation area that Japanese authorities had in place -- sparked international concern about the extent of the crisis at the tsunami-stricken Fukushima plant earlier this month.
A committee of top engineers that advises the U.S. Nuclear Regulatory Commission and reviews all its studies and license applications said it wants access to all the modeling data for the evacuation call.
"This was a very, very important decision. I would have expected there would have been high-level conversations between our regulatory bodies and our government (with their Japanese counterparts)", said Sam Armijo, former head of GE's nuclear fuel business, who invented the fuel cladding used on boiling water reactors.
"I want to make sure we get the analysis and the numbers that were actually used," Armijo said.
Regulatory staff had few answers for the advisory committee, which will review the NRC's response to the Japan tragedy, but they promised to deliver the calculations.
NRC staff said that after the third explosion at the Fukushima complex, they spoke with a Japanese regulatory official.
"There was limited and uncertain data," said Randy Sullivan, a senior emergency preparedness specialist.
The NRC was worried about the condition of pools holding spent fuel, and assumed they would contain as much radioactive waste as similar pools at U.S. plants -- something that turned out not to be the case, Sullivan said.
Using a computer model and assuming 100 percent damage to the No. 2 reactor, the NRC staff produced an estimate of risks and recommended the larger evacuation area.
The recommendation was not based on actual data from the site, which was unavailable, Sullivan said.
"Maybe the Japanese had some of that, but we didn't, alright?" he told the committee during a heated, lengthy question period.
Some of the NRC's assumptions were based on press reports, said William Ruland, the NRC's acting deputy director of engineering and corporate support.
"In an emergency event, you go with the best available information you have at the time," Ruland said, noting Japanese counterparts were focused on containing the situation rather than providing U.S. officials with information.
Michael Corradini, head of the nuclear engineering department at the University of Wisconsin, said the NRC's evacuation recommendation left him "confused."
He questioned why the NRC did not correlate its modeling with data from radiation monitors in the country before publicizing its recommendation.
"Thirty-two years ago, if Japan would have done a what-if calculation on Three Mile Island and said all the Japanese within 50 miles of Harrisburg should get out, what would be our response, from a policy standpoint?" Corradini said, referring to the worst-ever U.S. nuclear disaster that happened at the Three Mile Island plant in Pennsylvania in 1979.
