Woodford McClellan, a professor at the University of Virginia, was delighted yesterday by the State Department's confirmation that he'd soon get his Christmas wish: a reunion with his Soviet-born wife.

"I don't know how they knew my Christmas wish," McClellan said, laughing. "But they're right."

McClellan and his wife, Irina, are among 10 couples expected to be reunited next month as a result of an agreement that preceded the Geneva summit between President Reagan and Soviet leader Mikhail Gorbachev and of the general warming of relations that has followed. A State Department spokesman said yesterday that the Soviets had granted exit visas to the 10 persons. However, the spokesman declined to name the individuals.

But McClellan was not reluctant to acknowledge in a telephone interview that his wife was among those granted a visa. At 11 1/2 years, McClellan said, theirs is the longest of any Soviet-enforced separation involving a Russian spouse and an American native. "Unfortunately," he said, "we hold the record."

The couple persevered, he said, because "on top of the bond of affection, we weren't going to let them defeat our marriage."

McClellan and his wife met when he was 38 and she was 34. "I'm now 51 and she's 47," he said, "but to me she'll always be 34."

McClellan, a professor of Russian history in Charlottesville, said he expects his wife and her 26-year-old daughter by a previous marriage to arrive sometime in late January at Baltimore-Washington International Airport. World Airways, he said, has offered free transportation from Europe.

His reaction, he said, is a Russian phrase that translates: "Glory to God!" But, he added, "I'm going to believe it when she lands at BWI."

McClellan said he was notified on Nov. 15 by Deputy Undersecretary of State for Political Affairs Michael Armacost that the Soviets -- in a move interpreted by many as a presummit gesture -- would allow his wife to emigrate. Eighteen days later, his wife got "direct, face-to-face confirmation" from Moscow officials that she could leave, he said.

The professor then hoped that the reunion might take place before Christmas. "That was an unrealistic wish," he said yesterday.

The couple met in August 1972 when McClellan accompanied a Canadian tour group to the Soviet Union, lecturing on Russian history in exchange for a free ride. In the Caucasus Mountains, a Soviet-assigned Intourist guide introduced her friend, Irina, to the group.

McClellan saw his future wife again on two week-long trips in 1973. In December of that year, he returned once more as part of an official U.S.-U.S.S.R. exchange of university professors, and the couple married in May 1974.

Three months later, when McClellan had to come home, Soviet officials refused to let Irina leave. Because she had worked at a Moscow think tank, he said: "They said she knew state secrets and would have to wait a year to 'clear her mind.' "

At the time, according to McClellan, divided spouses were kept waiting no longer than two years and the couple was optimistic. But with the ups and downs of U.S.-Soviet relations, the waiting period grew. Hopes rose as Presidents Ford and Carter met with Soviet leaders, then fell again.

Coinciding with their ordeal, said McClellan, Irina's daughter suffered a severe ulcer ailment. She has undergone two major operations, the latest last March, he said. "Irina told me, and I understood the decision, she could not come without her daughter," he said.

McClellan and his wife corresponded regularly and talked by telephone about six times a year. They do not talk more often, according to McClellan, because "it's too emotionally draining."

He expects to travel to the Soviet Union again in the future. "I'd like to go and I intend to go," he said. "It's my life's work." But for his wife, whose elderly mother is still living, he said, "I think it would be a long time. I'm sure she'll miss her native land, but I don't think that would be very wise."

"It was easy for me, living in a free country, to write letters and keep up the campaign," he said. "But for her to defy the Soviet authorities -- it took incredible guts."

American diplomats reportedly said Thursday in Moscow that some Russians who have received exit visas may leave as early as today.

McClellan is the only Washington area resident whose spouse is among the 10 given the visas.