Prof. Emil J. Konopinski, who helped design the first atomic bomb and made testing of the first hydrogen bomb possible by showing that it would not destroy the world, died Saturday at Bloomington Hospital after a long illness. He was 78 years old. The cause of death was not disclosed.
Dr. Konopinski, a physics professor emeritus at Indiana University, worked with Enrico Fermi on the construction of the first nuclear reactor at the University of Chicago, then went to the Los Alamos National Laboratory in World War II with J. Robert Oppenheimer and Edward Teller to begin research on the first atomic bomb.
In tracing the history of the hydrogen bomb, Dr. Teller in 1955 paid tribute to Professor Konopinski. He said scientists were concerned that a thermonuclear explosion might spread, but Dr. Konopinski's calculations proved that the reaction would not ignite the atmosphere and oceans and destroy the earth.
From 1946 to 1968 he served as a consultant to the Atomic Energy Commission and was the author of ''The Theory of Beta Radioactivity.''
Survivors include a brother, Eugene W. Konrad, and a sister, Marian Hansen.