A Washington antinuclear group yesterday disclosed previously secret routes the Nuclear Regulatory Commission has established for shipments of atomic wastes through and around the Washington region.

Official documents obtained by the group show the NRC has, at least since the beginning of the year, rerouted interstate shipments of highly radioactive products away from heavily traveled roads near Washington to less populated areas in the western part of Virginia.

In an effort clearly aimed at arousing public objections to the shipments in towns along the new routes, a spokesman for the group, Potomac Alliance, said yesterday the shift exposes ill-equipped and untrained local safety agencies to the dangers of a nuclear accident.

"We think the public has a right to know what risks they're being exposed to," said Fred Millar. "We expect many communities will look at the lack of safety precautions and pass ordinances to stop [shipments]."

An NRC spokesman yesterday discounted the group's claim that the shipments endanger people living near the routes. "The spent fuel is shipped in very sturdy containers," he said.

Potomac Alliance, which aims to block all such shipments in Virginia, obtained the documents last week through a Freedom of Information request filed with state officials.

The documents reveal for the first time the federal agency's choice of Interstate 81 between Winchester and Pulaski as an alternative to the I-95 corridor between Washington and Richmond for transporting dangerous radioactive wastes to and from burial and reprocessing sites in South Carolina.

(Other routes take nuclear materials from the Calvert Cliffs power plant in Maryland through Fredericksburg and Warrenton on Rt. 17, headed for Ohio. Materials arriving from Europe leave Portsmouth for South Carolina on U.S. 58.)

They also show that as late as February the federal agency and state officials disagreed about whether the rerouting should be made public.

With one of the country's few nuclear waste disposal sites located in Barnwell, S.C., and the Department of Energy's Savannah River reprocessing and storage plant in nearby Aiken, Virginia has become a major crossroads for nuclear materials traveling up and down the East Coast.

The NRC, citing risks of sabotage, has guarded the scheduling and routing of waste shipments as highly secret. And until recently, atomic garbage traveled through the state in a manner sometimes known only to the shippers themselves.

Last year the NRC adopted new regulations requiring approval of shipment routing and diverting high level radioactive material, such as spent fuel and weaponry, away from populous areas. Virginia recently responded in kind, requiring that shippers show proof of NRC approval before it allowed trucks to cross state lines.

In February, the NRC's safety director, William J. Dircks, wrote Virginia Gov. John N. Dalton complaining that the state's new regulations might lead to disclosure of shipment routing.

Information regarding specific routes and proposed scheduling of spent fuel shipment is treated by NRC as 'confidential' information and not released outside of government and industry channels," Dircks said in a letter obtained by the group last week through its freedom of information request. "There is no concern with releasing this information to your designated coordinator; however, we are concerned that persons outside of official channels may also have access to the information and thus possibly compromise a shipment."

In a draft letter dated Feb. 29, suggested as a response from Dalton, State Health Commissioner James B. Kenley replied that, "given our need to provide radiation emergency response training to emergency service organizations along the routes . . . we believe that simply the number of people involved makes it unrealistic to consider this information as 'confidential.'"

The NRC spokesman said yesterday that, directed to do so by Congress, the agency planned to make its new routes "available publicly" within the next two weeks.

Alliance members, thwarted in previous court attempts to stop nuclear shipments in the state, said they hope residents will follow the lead of dozens of jurisdictions around the country and simply ban the materials from their turf.