OAK RIDGE, TENN. -- The fee received by Martin Marietta Energy Systems for running U.S. Department of Energy facilities here increased to more than $7 million for the second half of fiscal year 1987, documents show.

According to information released last week, the Martin Marietta subsidiary received a performance rating of "excellent" and a payment of $7,184,375 for the six-month period ending Sept. 30.

Martin Marietta received $6.9 million in payments the previous period.

The company runs the Oak Ridge National Laboratories and the Y-12 nuclear munitions plant for the federal government.

The government pays the Martin Marietta unit a fixed annual fee of $4 million, plus an additional payment based on the firm's performance evaluations.

The highest possible fee for the most recent period was $9,712,500, officials said.

In a letter to company officials, Department of Energy Manager Joe LaGrone praised the Oak Ridge facilities, but noted some areas for improvement, officials said.

Several of LaGrone's comments referred to the 107-day strike by hourly workers, the longest in Oak Ridge history.

"I would like to commend the entire Energy Systems management and staff for the effective operation of Y-12 and ORNL in a safe, secure and environmentally acceptable manner during the strike," LaGrone stated in his letter to Martin Marietta.

LaGrone said Martin Marietta's efforts minimized the impact of the strike on the plant.

Among the areas cited as needing improvement were the security program at the laboratories and security concerns discovered at the K-25 plant.