BRATTLEBORO -- The possibility that a spent fuel pool could be damaged by an earthquake allowing radioactive materials to escape into the environment is one in 10 million years, according to a draft study released Monday by the Nuclear Regulatory Commission.
The draft study was in response to the nuclear disaster in Fukushima, Japan, in which an earthquake and resultant tsunami damaged reactors similar to the one operating at Vermont Yankee nuclear power plant in Vernon.
The study was based on previous research showing earthquakes present the dominant risk for spent fuel pools.
The NRC is now asking for public comments on the draft study, which is meant to examine if faster removal of spent reactor fuel from pools to dry cask storage significantly reduces risks to public health and safety.
In Fukushima, though the reactors were damaged, releasing radioactive materials into the environment, the spent fuel pools survived the earthquake.
In its draft study, the NRC considered an earthquake several times stronger than what the pool's design is built for.
The study examined both a full spent fuel pool and one with less fuel and more spacing between individual fuel assemblies, as well as emergency procedures for adding water to the pool in the unlikely event that the earthquake causes the pool to lose water.
"Our detailed analysis showed that even a very strong earthquake has a low probability of damaging the pool studied to the point of losing water," said Brian Sheron, Director of the NRC's Office of Nuclear Regulatory Research. "The draft study also shows that even if this particular pool was damaged, the fuel could be kept safely cool in all but a few exceptional circumstances. We'll use the final study to inform further analysis of U.S. spent fuel pools."
The study also examined the potential benefits of moving all spent fuel older than five years into storage casks within five years. The study concluded faster fuel transfer to casks would not provide a significant safety benefit for the plant studied.
In cases where the analysis led to fuel damage, the draft study concluded existing emergency procedures would keep the population around the plant safe. Those emergency measures could mean relocating people from a large area of potentially contaminated land.
The study will be available on the Regulations.gov website, as well as in the agency's electronic document database, ADAMS, under accession number ML 13133A132. The NRC will incorporate public comments and use the final study in a broader regulatory analysis of the spent fuel pools at U.S. operating nuclear reactors as part of its Japan Lessons -- Learned activities.
The public and interested groups can comment on the study, using Docket ID NRC -- 2013-0136 on the Regulations.gov website, for 30 days following publication of a notice in the Federal Register, expected shortly.
Comments can also be submitted, using the Docket ID, via mail to: Cindy Bladey, Chief, Rules, Announcements, and Directives Branch (RADB) Office of Administration, Mail Stop: TWB-05-B01M U.S. Nuclear Regulatory Commission Washington, D.C., 20555.