MOSCOW -- Ilya M. Frank, 81, a scientist who won the Nobel prize for physics in 1958 for his work in neutron physics, has died, Soviet television reported yesterday.

The evening newscast "Vremya" said Mr. Frank died Friday. It did not report the cause of death or list survivors.

Mr. Frank was praised as an "outstanding Soviet physicist" who made a "substantial contribution to nuclear physics."

"Soviet science suffered a great loss," the announcer said as a photograph of Mr. Frank appeared on the TV screen.

The obituary was signed by Communist Party and government officials, as well as fellow scientists.

Mr. Frank was born in 1908 in Leningrad and graduated from Moscow University in 1928. He worked at the Leningrad Optical Institute and the Lebedev Institute of Physics. In 1944, he became a professor at Moscow University and in 1957 was put in charge of the university lab.

He shared the Nobel prize in 1958 with two other Soviets, Pavel Cherenkov and Igor Y. Tamm. He also received the Soviet Union's Lenin Prize.

The scientist was a specialist in physical optics and nuclear physics who, along with Tamm, explained the nature of and developed a theory on neutron physics.