Lyle Borst, 89; Physicist Key to First Peacetime Nuclear Reactor, Teacher

Lyle B. Borst, 89, a University of Chicago physicist who helped build Brookhaven National Laboratory’s nuclear reactor and was a member of the Manhattan Project, died July 30 in Williamsville, N.Y. The cause of death was not reported.

He led the development of the Brookhaven Graphite Research Reactor, the first nuclear reactor built for peacetime use, in 1950. In its first year of operation, he announced it had produced a new type of radioactive iodine, used to treat thyroid cancer. Studies using the reactor also helped him explain the giant stars called supernovae.

He was a founding member of the Federation of Atomic Scientists, which was created to raise awareness of the destructive potential of nuclear energy.

Borst, a Chicago native, earned his bachelor’s and master’s degrees at the University of Illinois and his doctorate at the University of Chicago. He worked as a researcher at the metallurgical laboratory in Chicago, where the first self-sustaining nuclear reaction was conducted by Dr. Enrico Fermi.

He later taught physics at the University of Utah, New York University and the State University of New York at Buffalo.