Link Miles Corp. of Columbia, Md., is counting on the belief that practice makes perfect -- particularly in running a billion-dollar plant.

Link Miles manufactures control-room simulators for nuclear power plants -- realistic reproductions that are used to train plant operators. Each one costs between $12 million and $15 million and takes 2 1/2 to 3 years to build.

In the last decade, the company reaped some benefits of increased interest in training and safety issues after the near disaster at Three Mile Island in 1979. Now that nuclear power plant construction has stagnated in the United States, however, Link Miles is looking for new ways to market its services -- and two contracts the company recently garnered may be the answer.

Last month Link Miles signed a landmark agreement with NPO Energia, a branch of the Soviet energy ministry, to help build control-room simulators for Soviet nuclear power plants for at least the next 12 years.

Since the Chernobyl disaster, the Soviet Union has been going through the same crisis that this country faced after Three Mile Island, said Gill Grady, Link Miles's director of contract administration. Soviet officials recognize that the Chernobyl incident might have been averted had plant operators been through more exact and effective training, he said.

Grady said the Soviet Union is "committed to nuclear power," with about 50 plants operational and another 30 planned or under construction. But until now, it has used solely its own resources to build and run its power plants and training facilities, he said.

"They have finally gone out to the West ... because, with so many export restrictions {in Western countries}, they just don't have access to the computing power" necessary to make adequate simulators for training, Grady said.

The software used in control-room simulators is so sophisticated that the usual specification "is written so that the operator can't tell the difference between the real control room and the simulator," he said. That means operators can go through emergency procedures that never could be tested at an actual plant.

Link Miles also sees its contract with the Soviets as a "springboard into new activities," Grady said. "We hope to expand beyond nuclear simulators and into {fossil fuel-based} power plants, and into ... Eastern Europe."

The company also plans to take advantage of these same software developments to tap the domestic market, Grady said.

Almost 10 years ago, Link Miles built a simulator for Pennsylvania Power & Light's Susquehanna nuclear power plant, and earlier this year it won a contract to modernize that simulator.

"It's going to be almost a whole new simulator to replace the one they have," Grady said. "Since we've been building these things since the '70s, there are quite a few simulators out there that could be upgraded."

At the time of the Three Mile Island incident, there were only about 10 nuclear power plant control room simulators nationwide, according to the Nuclear Regulatory Commission. Now there are more than 70.

As of May 1991, every nuclear plant seeking an NRC license must prove that its operators are trained on a simulator that exactly duplicates the plant's control room, Grady said.

But others in the industry say the U.S. market for simulator manufacturers will not be limited merely to updating software.

Edward M. Davis, president of the American Nuclear Energy Council of Washington, said the increase in electricity demand, along with growing concern about the environmental effects of burning fossil fuels, probably will spur construction of new nuclear plants in the mid-1990s.

"If the industry is able to resolve some of the institutional impediments, such as the government's process for licensing power plants, which has proved to be unworkable ... then it's very likely that utilities will once again order nuclear power plants to meet future demands," Davis said.

"Demand is catching up with supply and supply is tight," he said. "As the electricity supply tightens up, there will be more political resolve. It could be a real strong market."