By Ayesha Rascoe
WASHINGTON (Reuters) - A top Senate Democrat on Monday urged the U.S. nuclear regulator to require plants to speed up the shift of radioactive waste to dry cask storage from pools.
Senator Dianne Feinstein of California, head of a Senate Appropriations subcommittee that oversees energy agencies, said dry cask storage systems for nuclear waste are safer than spent fuel pools.
"The lesson from Japan's disaster is that we must be prepared to respond to unanticipated threats," Feinstein said in a letter to NRC head Gregory Jaczko. "Therefore, any policy changes that further reduce risks of an unsafe situation catching the industry off-guard should be implemented."
Spent fuel pools have exacerbated Japan's efforts to avert a total meltdown at its Fukushima Daiichi complex, which was hit by a 9.0 magnitude earthquake and tsunami last month.
The struggle to cool down nuclear waste in the damaged pools in Japan has raised concerns about use of similar pools in the United States. Used nuclear fuel is stored in pools for years, or even decades, as it cools down, but some lawmakers say companies should move the waste to dry storage faster.
Feinstein said a 2006 study by the National Research Council found that an accident or terrorist attack involving used fuel on a dry cask would be easier to contain and to recover from than if waste stored in pools was compromised.
Feinstein raised similar concerns about spent fuel pools with NRC's Jaczko at a hearing last month. Jaczko told Feinstein then that the NRC had determined that waste could be safely stored in pools for 100 years, although it would likely be moved to dry storage before then.
(Editing by David Gregorio)