The planned $8 billion Kansai International Airport outside Osaka has become a symbol of Japan's unwillingness to open its markets to foreign companies. American construction firms have complained that the Japanese have structured bidding on the project in such a way that only Japanese firms can win the contracts.

But TRW Inc.'s Fairfax-based federal systems group apparently beat the odds last week, winning a $340,000 contract that is one of the first to be given to an American company without Japanese partners. TRW is to perform a fact-finding survey of the airport's planned security system.

To date, contracts worth $2 billion have been awarded for work on Kansai, but less than $2.2 million of those have gone to American firms, and most of those winners have had Japanese partners.

"It is a very competitive environment. You have to take the time and energy to understand the culture. But once you can understand it, you can sell within that culture," said Daryl K. Solomonson, program manager for TRW's federal systems group. "I don't believe U.S. companies have an unfair disadvantage in the Japanese market."

TRW has had offices in Tokyo for 27 years and has been doing security work for the Japanese government for the past six years. Solomonson said he hopes the Kansai contract, which will be completed in February, will lead to others for the airport. "We hope to be involved until the system is put in place," he said.

Under the contract, TRW will help design a security system into the plans for the airport's facilities. Solomonson calls it a "front end system," as compared to most security systems, which are designed and installed after buildings have been completed.

"As a systems engineering company, we look at the whole system and the design we create will lead to the type of hardware we use, rather than the hardware leading to the type of design," Solomonson said.

Dominion Bankshares Corp. of Roanoke has announced plans to purchase its third bank in eastern Tennessee: Merchants and Planters Bank of Newport.

Last month, Dominion announced plans to purchase Greene County Bank and Citizens Union Bank. With the addition of Merchants and Planters Bank, Dominion has assets of about $750 million in the tri-city area of Johnson City, Kingsport and Bristol.

Under an agreement with Merchants and Planters Corp., the holding company for the bank, Dominion will issue 6.16 shares of common stock for each share of Merchants and Planters common stock. The transaction is valued at $19.5 million.

"We need the competitive advantages of a large company like Dominion while retaining our ability to respond to the specific needs of the region we serve," said James E. Robinson, president of Merchants and Planters.

The takeover is subject to approval by Merchants and Planters shareholders and regulatory authorities.

Contel Corp.'s federal systems sector said its applied systems division has been awarded a $24 million contract to help replace the telephone system at the Department of Energy's Idaho National Engineering Laboratory.

The laboratory is a center for nuclear safety, defense programs, nuclear waste technology and advanced energy concepts. It includes the largest concentration of nuclear reactors in the world.

Under the 10-year contract, Contel will install two of the three systems that make up the complex's communications network. The first system, called digital information exchange, can handle 8,000 lines of voice and data simultaneously. The other system transmits voice, data and video through fiber optics cables.

Contel is acting as a subcontractor to EG&G Idaho Inc., the prime contractor for DOE at the Idaho laboratories.

American Management Systems Inc. of Arlington has won a $5 million, three-year contract to help the Department of the Interior combine its 10 accounting systems into one.

"This is the first time a large federal department has turned to the private sector to purchase existing software and tailor it to serve government accounting needs," said Secretary of the Interior Donald Hodel.

Under the contract, AMS will develop financial-management software, update it during the next 10 years and train more than 1,000 accountants and managers.

The system first will be installed in the U.S. Geological Survey headquarters in Reston and at the Bureau of Reclamation in Denver. Other department bureaus should have the system in operation by October 1990.

Interferometrics Inc. of Vienna is using the ancient technique of celestial navigation to obtain sophisticated information on the motion of the earth's crust under a $3.2 million contract with the National Aeronautics and Space Administration's Goddard Space Flight Center.

The company is providing scientists for the center's Crustal Dynamics project, which is trying to determine the precise shape of the earth's surface and improve earthquake prediction by measuring the earth's angles to stars.

"Stars are known locations. We can measure motion in the earth's crust by using the stars as constants," said Brian Horais, vice president of Interferometrics.

Hagler, Bailly & Co. of Washington has bought Energy and Resource Consultants Inc. (ERC), a $2.5 million Denver company, for an undisclosed amount.

Both companies are economic consultants to government agencies and private institutions. "Our expertise in utilities and energy economics and their expertise in environmental planning and electric utilities were a good match," said John Franke, manager of marketing and business development at Hagler, Bailly.

Michael Yokell, now president of Energy and Resource Consultants, will become chief operating officer of the combined entity, and Henri-Claude Bailly will remain as chief executive officer of the company.

USTravel Systems Inc., based in Rockville, has added another link to its national network of travel agencies by buying Executive Travel in Anchorage, Alaska.

The acquisition is the fifth this year by USTravel, which operates travel agencies in the Washington, D.C., area and the Pacific Northwest.

The Alaskan company will merge operations with Doug Fox Travel, a large travel agency in Seattle that was purchased by USTravel in January. The merger will give Executive Travel access to Doug Fox Travel's services in Washington state, Oregon and Alaska, but Executive Travel will keep its name and management. Executive Travel has 24 employes in six offices across Alaska.