By Roberta Rampton and Emily Stephenson
WASHINGTON (Reuters) - The U.S. nuclear regulator is refining a plan to change its rules for power plants following Japan's Fukushima disaster, selecting half a dozen high-priority items to tackle first, senior staff said.
The Nuclear Regulatory Commission is sorting through how to update its requirements for plants to withstand earthquakes, floods and other natural disasters -- a detailed and involved process expected to take years.
The first changes likely will include requiring operators of the country's 104 reactors to take a new look at the risks posed by earthquakes and floods.
"The full re-analysis that's proposed ... will take some time," said Amy Cubbage, who was part of an NRC taskforce that compiled a list of changes for U.S. reactors after a quake and tsunami in March overwhelmed the Fukushima Daiichi plant, causing the world's worst nuclear disaster in 25 years.
By October 3, NRC staff will advise the five-member commission on logistics for the changes and how to weave in input from the industry, the public and an advisory committee.
Senior staff discussed the changes with industry and nuclear critics at a public meeting on Wednesday.
Seismic risks in the United States were highlighted last week by an earthquake in Virginia that may have shaken Dominion Resources' North Anna plant more severely than the facility was designed to withstand.
"We need to look and see if we can learn lessons from anything that's happened, whether it was the earthquake in Japan, or whether it was even the earthquake under Lake Anna," Timothy Greten, a policy specialist at the Federal Emergency Management Agency, said at the NRC meeting.
WITHOUT UNNECESSARY DELAY
NRC staff proposed the agency move forward on ordering upgrades to reactors with designs similar to the Fukushima plant and improvements for pools that store radioactive spent fuel.
The agency thinks the changes can move forward "without unnecessary delay" but gave no more specific timeline.
Other items identified by the NRC's Fukushima taskforce will need further study in a longer-term review, including its top recommendation to overhaul the "patchwork" of rules and guidelines into a more streamlined regulatory structure.
It will take years for the agency to adjust its regulations and for the industry to implement the changes. NRC Chairman Gregory Jaczko has urged that the work be complete within five years, which would be an accelerated timetable for the agency.
SEISMIC RISK REVIEW PROPOSED
Separately, the NRC on Wednesday said it would require that plants evaluate their seismic risk, part of a process that started years before the Fukushima disaster.
"In view of the potential safety significance of this issue, it is necessary to reexamine the level of conservatism in the determination of original seismic design estimates," the NRC said in a Federal Register notice.
While there is no "imminent risk" from the design of aging plants, there is higher earthquake hazard in parts of the central and eastern United States than was assumed when they were first designed, the NRC said.
(Editing by Dale Hudson)