Cleaning up environmental contamination and correcting other problems at the nation's nuclear weapons plants could cost as much as $70 billion and extend beyond the year 2010, according to government estimates released Friday.

The report was prepared by the U.S. Department of Energy and released by Sen. John Glenn, D-Ohio, who had requested it.The department issued two sets of estimates, an "expected" projection representing the most likely requirements for each site and a "high" projection of what could be required to meet more stringent interpretations of existing laws, regulations and policies that could reasonably be imposed on the defense plants.

"Within those bounds, the cleanup of contaminated sites and corrective actions could require between $40 billion and $70 billion in addition to an ongoing base program of $700 million per year," the department concluded.

The evaluation included 17 defense plants. It said most of the remedial cleanup actions could be completed within 20 years.

Environmental corrective actions could include such things as improvements in stack exhaust, construction of radioactive waste treatment facilities, upgrading drinking water supplies and other activities.

By far the largest single price tag for cleanup and corrective actions is for the Hanford, Wash., site. The department estimates the cost at between $27 billion and $46 billion from fiscal 1995 on and projects it would take between 30 and 50 years beyond that to complete remedial environmental action there.

A sampling of possible major environmental projects at the defense production plants includes:

- an environmental restoration program at Los Alamos National Laboratory in New Mexico, $1.4 billion;

- environmental restoration at the Hanford site, $650 million;

- a buried waste program at Idaho National Engineering Laboratory, $500 million;

- environmental restoration at the Rocky Flats (olo.) plant, $345 million;

- a basin closure program at the Savannah River (.C.) plant, $70 million;

- groundwater and soil investigations at Lawrence Livermore National Laboratory in California, $59 million;

- waste pit and silo remediation at the Feed Materials Production Center near Fernald, Ohio, $40 million;

- cleanup of polychlorinated biphenyls at the Portsmouth Gaseous Diffusion Plant near Piketon, Ohio; $38 million;

- and environmental, health and safety actions at the Mound plant in Miamisburg, Ohio, $30 million.

The department also said major safety and health projects could include plantwide fire protection at the Savannah River plant, $200 million; an upgrade of the ventilation system at the Fernald plant, $55 million; and an asbestos management program at Los Alamos, $52 million.