OBITUARIES : Valery A. Legasov, 51; Chernobyl Investigator

Valery A. Legasov, head of the commission that investigated the Chernobyl nuclear power accident two years ago, has died at the age of 51, the Soviet news media announced Friday.

Neither Tass nor the evening television news broadcast Vremya gave the cause or place of death.

The official Tass news agency said Legasov died Wednesday, a day after the second anniversary of the April 26, 1986, explosion and fire at the nuclear power facility in the Soviet Ukraine that killed at least 31 people.

It was not known if Legasov--head of the I. V. Kurchatov Institute of Atomic Energy in Moscow and a noted reactor designer--was exposed to dangerous levels of radiation while investigating the Chernobyl disaster, the world’s worst nuclear power accident.

Soviet leader Mikhail S. Gorbachev and other top Communist Party officials and scientists signed the obituary carried by Tass.

Legasov’s name had been absent from the dozens of Soviet media reports on Tuesday’s anniversary of the accident at the nuclear facility 80 miles north of Kiev. He did not appear at a Moscow news conference held by the Soviets’ top nuclear power specialists Wednesday to discuss the present situation in the Chernobyl area.

Legasov’s foreign colleagues in nuclear power research had praised his openness in discussing the causes and effects of the Chernobyl accident, in contrast to initial Soviet delay in releasing information about it.

The accident spread radioactivity worldwide.

A physical chemist, Legasov was the first deputy director of the I. V. Kurchatov Institute of Atomic Energy and was a member of the Presidium of the Soviet Academy of Sciences. The official obituary praised his work in the use of nuclear reactors to generate electricity and also his work with inert gases.

Legasov headed Soviet delegations to meetings on the Chernobyl disaster of the Vienna-based International Atomic Energy Agency.

In August, 1986, he made a five-hour presentation of the Soviet investigators’ report on Chernobyl to the agency. The report blamed human error rather than faulty equipment.

Tass said Legasov made a “significant contribution in the working out and realization of immediate measures aimed at liquidating the consequences of the accident.”