The burial of more than 50 million pounds of radioactive waste around the government's nuclear weapons and research facilities at Oak Ridge, Tenn., poses no health threat to nearby residents, the National Academy of Sciences said yesterday.

"Neither calculated nor measured cumulative radiation doses to residents of Oak Ridge appear to be different from natural background levels," a 10-member study panel of the National Research Council, the academy's research arm, said in a report to the Energy Department. "Impacts on the health of people living offsite are so small as to be trivial."

The report supports the conclusion of government officials that nearly 70 millions tons of uranium buried at Oak Ridge, and near related atomic facilities at Paducah, Ky., and Fernald, Ohio, are not a health threat.

However, the panel said safe disposal sites are becoming increasingly difficult to find. And, citing small leaks of radiation in the past from the burial sites, it warned that radionuclides will continue to escape into surface waters unless future practices are "radically different from past ones."

Since the Oak Ridge National Laboratory began handling the disposal of nuclear wastes, it said, scientists have concluded that the site 25 miles west of Knoxville is "a poor hydrogeologic choice" for the shallow burial of nuclear wastes. Thus it questioned the Energy Department's plans to locate two new radioactive burial grounds near Oak Ridge because of their vulnerability to groundwater intrusion and leaching.