WASHINGTON — The nation's top nuclear regulator is assuring residents of the Wasatch Front they will not suffer health or environmental risks should 4,000 casks of spent nuclear fuel be stored in Tooele County, even in the unlikely event that a terrorist attack breached some of the containers.

Nils A. Diaz, chairman of the Nuclear Regulatory Commission, told reporters at the National Press Club on Monday the canisters are designed to withstand attacks and "pose no radiological hazard with the present weaponry" available to terrorists.

"I think the casks there will be well protected," Diaz said.

The NRC chairman said the concentration of canisters in one location could make it so that an attack — by an aircraft flying into a cluster of casks, for example — could result in damage to a few casks being knocked into one another. But even if the casks were breached, the radiation leakage would be confined to the immediate impact area, and radiation would not extend beyond a two-mile zone around the site, he said.

The NRC will soon ratify or reject the recommendation of the Atomic Safety and Licensing Board that Private Fuel Storage be granted an NRC license to store spent fuel for up to 40 years in above-ground casks in Skull Valley about 70 miles southwest of Salt Lake City.

The NRC is expected to approve the PFS license, although Diaz insisted the NRC does not rubber-stamp decisions by the Atomic Safety and Licensing Board, an independent judicial arm of the NRC. In at least three or four recent cases, the NRC went against the board's recommendation, Diaz said.

Whether PFS gets an NRC license and becomes operational are "both big ifs," he said.

Diaz pledged the NRC would review the official findings without political interference, most of it expected to come from the Utah delegation. Utah Gov. Jon Huntsman Jr. was in Washington, D.C., Monday also lobbying against PFS.

Huntsman, who has been pushing an agenda of waste storage at nuclear power plant sites and reprocessing of nuclear waste, told the Deseret Morning News that he was encouraged by meetings with Energy Secretary Sam Bodman, with whom he shared Utah's concerns over homeland security issues surrounding the site.

"We need to buy 30 to 50 years so the (reprocessing) technology can catch up," Huntsman said. "We need to buy time to accommodate a policy to allow on-site storage and reprocessing."