Christian Beck, 78, a retired engineer for the old Atomic Energy Commission and a former resident of Rockville, died Tuesday at a nursing home in Rosemont, Pa., of complications following a stroke.

A native of Norway, Mr. Beck earned a degree in civil engineering from the Technical University in Darmstadt, Germany, and moved to the United States in 1924. He was a civil engineer in New York City and Cleveland until 1940, when he moved to the Washington area to work for the old War Department and the Corps of Engineers.

In 1951, Mr. Beck joined the AEC and became chief of the design section in its construction division. In 1961, he was named staff structural engineer in the regulatory group. He retired in 1967 and then served as a consultant to the commission until retiring a second time in 1972. He moved to Bryn Mawr, Pa., in 1976.

His published writings included studies on nuclear reactor shielding and underground construction of nuclear power reactors. He was a life member of the American Society of Civil Engineers and a member of the American Nuclear Society.

Survivors include his wife of 49 years, Borghild A., of Bryn Mawr; a son, Leif C., of Villanova, Pa., and three grandsons.