The increase in the birthrates of non-Russian ethnic groups in the Soviet Union may by the '80s rearrange the fabric of Soviet social institutions, such as industry and the military, Edward L. Keenan '57, dean of the Graduate School of Arts and Sciences and professor of History, said yesterday in a lecture at the Science Center.

Demographics indicate that the population of non-Russian ethnic groups is increasing three times faster than the Russian population, Keenan told a group of 95 people attending the Summer School Thursday Lecture Series event.

Keenan said the total Soviet working force "is becoming younger and non-Russian." The working force in industrialized areas of the western Soviet Union, however, "is declining, threatening the industrial combines," he added.

The military is a not her social institution sensitive to demographic fluctuations, Keenan said. Russians usually hold the high-ranking positions while the non-Russians generally hold the middle and lower ranks, he added.

"Ukrainians usually hold the middle-ranking positions. And the old joke goes that a Ukrainian goes to boot camp and the first question he asks is, 'Where do the sergeants go?'" Keenan said.

After military duty, the rural soldiers generally go to the urban reas, and the urbanization of the Soviet Union is compounded further by rural Russians migrating to Moscow and the ruling cities, Keenan said.

The Russian population makes up slightly less than half of the Soviet Union, according to 1970 census statistics. Keenan said the "Roots phenomenon" may gain a greater hold in the 1980s.

"Although culture is a game people play, cultural politics is hard ball. The Georgians, for example, feel that they don't receive their fair share of the economic returns or power in politics. They contend this is because they are non-Russians," he said.

The non-Russians' roots were broken when the writers, scholars and poets were left out of the Soviet culture, Keenan said. "They were replaced with a bland, Russo-centered standard form of education," he added.

Keenan said he sees the Soviet system remaining constant. Although tension-ridden, it will be stable because of the use of repression, he said.

While limitations of culture on non-Russians will not let up either, feelings of ethnic identity are on the rise as the Soviet language takes on more word variations and different accents.

"Non-Russian nationalities play an important role in the dynamics of Soviet society," Keenan stressed.