New Nuclear Bomb Factories Planned by Energy Dept. : Defense: Officials say a modern complex would serve the military’s needs through at least the year 2050.

An Energy Department master plan for future production of nuclear weapons calls for revitalizing the existing network of factories and reactors so the military can make new bombs through at least the middle of the next century, according to department officials and government documents.

Despite improving U.S.-Soviet relations and the prospect of deep, negotiated cuts in superpower arsenals, the Department of Energy has based its research and spending plans on “a requirement for nuclear weapons as far as we can see,” a senior department official said Saturday.

While the size of the U.S. nuclear arsenal is expected to decline from its current level of about 21,000 weapons over the next 60 years, department officials say they are anticipating a continued need to manufacture many new weapons with safer designs.

“Complex 21, my vision of a fully modernized (nuclear weapons) complex, is planned to be in operation about 2015 and to support the nation’s strategic deterrent until the middle of the century,” Energy Secretary James D. Watkins said in a letter to the Senate Armed Services Committee.

Watkins told the committee that under one option being considered, “Complex 21”--for the 21st Century--may consist of one or two super bomb-building sites that would consolidate activities now spread across 12 states. This action would create what activists are calling “a nuclear weapons theme park,” which some officials say could be operated in a state such as South Carolina, where public support for the bomb-building enterprise and its attendant infusion of federal dollars remains high.

But after having officially scrapped a modernization plan prepared at the end of the Ronald Reagan Administration, Watkins said he expects that the final shape of “Complex 21” will not become clear until late 1993 or early 1994.

His timetable partly reflects a January decision--under threat of a lawsuit--to conduct a full-scale assessment of the environmental impact of modernizing the vast, troubled nuclear weapons manufacturing complex. That decision requires the department to conduct extensive public hearings.

It also reflects what one official described as Watkins’ desire to get a clearer picture of future U.S. defense spending, which likely will not stabilize for several years.

The timetable has the added benefit of postponing until after the 1990 elections the start of public hearings on an issue that has aroused substantial fury in localities where residents have been exposed to radioactive emissions or environmental contamination, such as the plutonium production complex at Hanford, Wash.

Officials said the Energy Department has been using six different scenarios for future nuclear weapons requirements in its preliminary planning, beginning conservatively at the current level of 21,000 weapons and heading downward toward a “minimum” nuclear force of close to 3,000 weapons.

“We’re not going to require (a nuclear weapons enterprise) as large, as complex and far-flung as the one we have today,” an official said. While emphasizing that no decisions have been made, he said that consolidation of the existing 17 facilities at one or two sites would sharply cut the cost of transporting weapons materials, increase security and allow less-fettered operation in a “more hospitable” climate.