Today's Coming Crisis Movie

Friday, June 17, 2011

Nuclear commission: U.S. reactors are safe (but please ignore the level 4 distress at Nebraska!)

The Nuclear Regulatory Commission told Congress on Thursday that the likelihood of a Fukushimi Daiichi-type event in the United States is "very, very small." However, it said an ongoing study of the Japanese disaster will probably lead to changes to increase safety at the nation's 104 commercial power plants.

The commission said, in a nutshell, it expects to require nuclear plants to be prepared for bigger natural disasters, to survive longer power outages and to consider the possibility of simultaneous disasters affecting multiple reactors, as happened in Japan.

Commissioner George Apostolakis said one of the lessons of Fukushima is "humility."

"I believe that, as a community of safety analysts, we were pretty confident that there would be no new surprises," Apostolakis said. "Fukushima has challenged that belief."

Commissioners said the commission's core safety concept, a belts-and-suspenders policy called "Defense in Depth," is sound. The policy requires power plant designers and operators to have multiple, redundant layers of defense to respond to failures so that no single layer of response is relied on. They also endorsed support for regulations that require plants to be designed to withstand the strongest natural disasters on record for that location, with an added margin of safety.

But while voicing support for both concepts, some commissioners said "Defense in Depth" needs to be deeper and margins of safety wider.

Currently, emergency plans for most U.S. nuclear reactors envision one nuclear reactor being in danger. At Fukushima, all four operating reactors were affected by the tsunami that followed an earthquake in March. The Nuclear Regulatory Commission also requires plans to evacuate a 10-mile zone around power plants, but U.S. authorities recommended that U.S. citizens within 50 miles of Fukushima evacuate. (read more)