Underground detonations are essential for perfecting new warheads. Thus, their cessation is often seen as a way to halt the nuclear arms race.

The Non-Proliferation Treaty, ratified in 1970, has no apparent prohibitions against commercial sales, as long as the blasts are for peaceful purposes. Its only conditions are that transfers from a nuclear power to a non-nuclear one occur "under appropriate international observation and through appropriate international procedures," and that the price be fair.

For decades the Soviets have led the world in applying nuclear detonations to civilian efforts, conducting more than 120 blasts. The United States also investigated such peaceful applications of the atom, but dropped the effort in the 1970's as fears arose about the contamination of the environment with radioactive residue from the work.

The Soviet Union used the blasts to create underground cavities for storing fuels and disposing of chemical wastes such as the brine produced by oil fields. Another use was to stimulate the production of gas and oil fields by shattering rock and releasing trapped pockets. They also used blasts to extinguish stubborn fires in gas wells, and to generate powerful shock waves that helped geologists learn more about the earth's crust and mantle.

Chetek, an acronym formed from the Russian words for man, technology and capital, was formed late last year to try to sell these and other nuclear technologies to the world. In particular, it has promoted the novel idea of using nuclear blasts to vaporize all kinds of extremely dangerous wastes. The destruction would occur a little more than a half mile beneath the earth's surface, where a nuclear bomb was surrounded by waste and then exploded. Marketing Campaign

The company's president, Vladimir B. Dmitriev, began a quiet marketing blitz in early April, hailing the process at an international scientific conference in Moscow on the elimination of chemical arms. "It will be possible to export services," Mr. Dmitriev told the conference. "The problem of chemical weapons and highly toxic waste products destruction is urgent for many countries of the world."

Later in April, Mr. Dmitriev traveled to Ottawa for a scientific meeting on the environmental consequences of underground nuclear testing, sponsored by the Canadian Center for Arms Control and Disarmament, a private group. There he startled the audience by detailing his company's plans and suggesting that a trial waste-elimination blast be conducted in the Soviet Union under international supervision.