An empty container used to transport used nuclear fuel lies on its side after a rail car carrying it derailed Sept. 22 in a collision involving two trains at the CXS Frontier Railyard in Buffalo, N.Y. The empty container was not damaged and there was no release of radiation, the Department of Energy said. Photo by The Associated Press

WASHINGTON -- Thousands of shipments of highly radioactive nuclear waste can be conducted safely, a panel of scientists concluded Thursday, although it said the Department of Energy has challenges to meet in shipping the waste to Yucca Mountain.

The report by a panel of the National Academy of Sciences is expected to carry considerable weight as the government moves toward developing a central repository in Nevada for used commercial reactor fuel and defense waste now kept in 39 states.

The study appeared to contain no potential showstoppers and few sharp edges, according to transportation analysts who reacted to the report. Officials from the state of Nevada found things to like, as did the Department of Energy and the Nuclear Regulatory Commission.

"In general, it reflected a lot of the recommendations the state has had for a number of years," said Bob Loux, executive director of Nevada Agency for Nuclear Projects.

Loux noted the academy called for full-scale safety testing for waste casks and a recognition that DOE faces "a huge impediment" because people perceive that nuclear waste will be dangerous as it passes through their communities.

On the other hand, Loux said, the scientists appeared to be supportive of a rural Nevada railroad line being considered for Yucca Mountain over the objections of the state and a number of ranchers along the corridor.

In one key recommendation, the panel said the Department of Energy should not commence shipments until it finishes building a 319-mile railroad through rural Nevada to the Yucca site. Uncertain whether it can get such a line built in time, DOE has been looking at plans to ship radioactive material by truck through the state as a stopgap.

DOE had no comment on that recommendation, spokesman Craig Stevens said. Otherwise, he said the study "validated many of our current practices," including plans to use dedicated trains and to move a majority of nuclear waste by rail and not by truck.

The group examined the risk from possible accidents as nuclear shipments crisscross the country, but said it did not assess security risks to such shipments because it could not gain access to classified information.

It called for a further examination of security issues, including a shipment's potential vulnerability to terrorist attacks. It also said that the group doing the investigation should be independent of any governmental or industry conflicts.

The Energy Department is preparing a transportation plan to ship some 77,000 tons of nuclear waste from around the country to Yucca Mountain, if the facility gets a license from the Nuclear Regulatory Commission.

The department said that would require 4,300 shipments -- about three-fourths by rail and the rest over highways -- over 24 years. Nevada officials, who strongly oppose the Yucca project, have said there could be as many as 50,000 shipments with waste going through at least 43 states.

The study by a special panel of the academy's National Research Council concludes there are "no fundamental technical barriers to the safe transport of spent nuclear fuel and high-level radioactive waste in the United States."

"The radiological risks ... are well-understood and are generally low," the report continued, noting that during 40 years of making such shipments there has never been a significant release of radioactive material.

But the scientists warned of "social and institutional challenges" -- from possible property value decline and loss of tourist business along transport routes to public anxiety over such shipments -- that would have to be overcome as the number of shipments increase.

That recommendation was a reflection of the unease expressed by residents of Nevada and other states, said Hank Jenkins-Smith, a public policy professor at Texas A&M University.

The Energy Department should "give serious attention to the community and economic impacts of the program," Jenkins-Smith said.

"The distrust that has mounted over years between (Nevada) and the government creates a really tough context for building the type of cooperation that really needs to be in place for ensuring safety as far as getting emergency responders up to speed," he said.

Associated Press Writer H. Josef Herbert contributed to this report.