The General Services Administration is studying a plan for a new Southeast Federal Center that could place 30,000 government workers in more than a dozen buildings to be built over the next 20 years at the old Washington Navy Yard.

"This is not a proposal to build a dozen new federal buildings at a cost of hundreds of millions of dollars tomorrow," cautioned GSA's Public Buildings Commissioner Richard O. Haase. "This is a master plan to allow us to . . . develop a valuable piece of government-owned property that is now underutilized."

Haase received the draft plan, prepared by the architecture firm of Keyes Condon Florance, last Monday.

The proposed facility would cover 60.5 acres and stretch from 1st Street to Isaac Hull Ave. (approximately 6th Street) and from M Street to the Anacostia River.

The plan suggests four primary themes for the development:

In the southeastern portion, the industrial character of the old gun and munition manufacturing buildings would be reused. Those buildings, closed after World War II and now GSA warehouses, would be interspersed with new structures. The facility would extend the character of the adjacent historic Navy Yard district, which is still under the Navy's control.

In the northwestern segment, new office buildings would emphasize "a light, taut new office character and reestablish the city-street grid with appropriate landscape relating to the adjacent Metro stop and proposed Capitol Gateway development."

Along the Anacostia River, a "dense and tight urban waterfront" setting that blends the industrial character with the rivers edge would include a riverfront drive, a bikeway and a walkway.

New Jersey Avenue would be extended through the site to the river, as a major north-south corridor. Tingey Street would become the major internal east-west corridor. At their intersection, a "central urban square" would be surrounded by 200,000 square feet of ground-level retail shops, ranging from boutiques to restaurants.

Extending New Jersey Avenue, GSA points out, would maintain the "vista" originally envisioned in L'Enfant's grand design for the District while development of Tingey Street would draw people in the facility to the adjacent Capitol Gateway development on 1st Street.

Along these corridors, historical industrial buildings would be converted to "sidewalk-oriented retail use in a festive manner."

Haase said the plan will now undergo "an intensive review" by his staff with an eye to making such improvements as adjusting the "office-space utilization rate" from the current 268 square feet of space per federal worker proposed by the consultants to the new government standard of 135 square feet.

"A simple change like that can mean another 10,000 federal workers could eventually work at the Southeast Federal Center at an immense saving to the taxpayer," Haase said, pointing out that it is GSA's goal to put 75 to 80 percent of federal employes in government-owned space. Currently, they are about equally divided between government-owned and leased space.

The latest plan for the area is the fourth in the last 20 years. The first, proposed in 1963,involved a much smaller federal center and a park stretching along the waterfront.

"The last thing we want to do by announcing that a preliminary plan has been completed is to panic people into thinking this is something that will happen tomorrow," Haase said. "This is not in GSA's seven-year construction plan, but maybe some of the buildings should be."

Jerry Shiplett, GSA's regional facility planning chief, said that proposals for development of the site have varied widely over the years.

"For example, after the 1968 plan, we begin rethinking how to adaptively reuse older buildings in conjunction with the new facility" because of the National Historic Preservation Act of 1966, Shiplett said. Before that, he said, plans had taken "more of a monolithic look at federal construction."

Over the past dozen years the Navy has tried to convince Congress that it should develop a Navy "Pentagon" on its 60-acre portion of the Navy Yard. Navy officials have wanted to triple their current 5,000-person contingent there, primarily by relocating employes now in leased space in Crystal City. Sen. John W. Warner (R-Va.) and other political leaders have opposed that move, claiming it would have adverse effects on Arlington County's economy.

Shiplett, who says the Navy plan is still "on hold, and not scuttled at all," said the latest proposal includes some data from the Navy's environmental impact statement pertaining to the transportation capabilities in the area.

Originally, GSA planned the Federal Center to house 15,000 people, but the Green Line Metro station and other factors convinced GSA to double that figure.

That change, and efforts to coordinate research with Navy planners, delayed the study, which was begun in July 1981, and raised its cost from $239,000 to $301,114.

The Navy Yard facility has been in the news recently because GSA Administrator Gerald P. Carmen discovered that efforts to clean up the dilipated warehouses ended in 1980.

Just two weeks ago, Carmen had said that the clean-up would leave several of the old industrial buildings virtually vacant and that the agency would consider selling them. At that time, he was unaware that regional officials were preparing a study on how to use the facility as a federal center.

Carmen has said he will look at the development draft with an open mind.