The United States exploded an average of 15 nuclear weapons a year -- more than one a month -- in the last two decades of its Cold War with the Soviet Union. Now, despite the disappearance of any real Soviet threat, the Bush administration plans to keep testing new generations of nuclear weapons for years to come.

In 1990 the Pentagon has exploded at least eight warheads under the Nevada desert, plus one in New Mexico. Hundreds of feet below the surface, their shock waves and flames typically incinerate $30 million in tunnels and test equipment to develop new, more accurate and powerful weapons that can fill no security need. Even today, U.S. military contractors continue to work on an earth-burrowing warhead meant to threaten the Soviet leadership in its underground bunkers.

Ironically, our continued testing adds nothing to deterrence but simply sends a dangerous message to non-nuclear nations: the more destructive your nuclear weapons, the more important you are. Iraq has heard this siren song. Although Saddam Hussein knows he could never match America's 20,000 warheads, he is jockeying to be the next member of the nuclear club. And each new member automatically recruits others.

Meanwhile, the Bush administration blocks progress in the international forum designed to prevent the Iraqs of the world from proceeding down the nuclear path -- the Nuclear Nonproliferation Treaty Review Conference. The term of the 20-year-old Nuclear Non-Proliferation Treaty expires in 1995. Rather than working to extend this regime by depriving nuclear weapons of their special cachet, the Bush White House evidently prefers to refine a nuclear arsenal it can never use.

The U.S. delegation's performance at the latest review conference, concluding Sept. 15 in Geneva, was particularly disturbing. It came less than a week after President Bush's amicable Helsinki meeting with Soviet President Mikhail Gorbachev. During that week, Bush had assured Congress in a televised address that one reason we are confronting Iraq is "to curb the proliferation of chemical, biological, ballistic missile and above all, nuclear technologies" (a theme he has sounded even more strongly in recent days).

Yet while Americans were fretting about nuclear weapons in the hands of Saddam Hussein, the Bush team was simultaneously holding up a final communique' at the NPT review conference that included many international agreements to hamper such Third World nuclear programs.

After that final all-night session, the conferees failed to reach a consensus or report any of their agreements. The U.S. diplomats refused even to talk about stopping our own nuclear test explosions, while Mexico -- with strong support from nuclear have-nots such as Venezuela, the Philippines, Kenya and Iran -- insisted on "good faith" talks toward a ban.

Since then, Gorbachev has renewed his own support for a test ban. On Oct. 20 in a telegram relayed through the Soviet Embassy in Washington, he promised to raise the issue when he next meets with Bush. Meanwhile, however, the Soviets broke a yearlong moratorium with an underground test blast on Oct. 25 near the Arctic Circle. They blamed the continuing U.S. program for their action.

Why do other nations object to such tests? One reason is that they are hazardous to the environment and nearby residents. (The Soviet Union has held no tests at its main site in central Asia since October of 1989, largely because of ill health effects and popular indignation after radioactive gases were vented in surrounding Kazakhstan.)

More important, however, is that we are missing a historic opportunity to discourage nuclear proliferation. "There is no point in reducing certain types of weapons if, at the same time, others are developed and improved," Ambassador Miguel Marin-Bosch of Mexico said at the talks. "Moreover, what is the sense of removing nuclear warheads from one region of the globe if later they are going to appear in another?"

In fact, both the 1963 Partial Test Ban Treaty and the original Non-Proliferation Treaty obligate the superpowers to work toward a comprehensive test ban, ending "all test explosions of nuclear weapons for all time." These treaties are part of U.S. as well as international law. By failing to negotiate, we violate that law. Two treaties signed this year with the Soviets to limit but not eliminate nuclear tests -- leftovers from the 1970s -- are only small steps in that direction. The permitted yields are more than 10 times that of the bomb that leveled Hiroshima. Yet those who run the U.S. weapons program say further steps to limit testing can't be considered for 10 years or more. At that rate, a comprehensive ban could take another century.

This is wrong. An amendment to the 1991 defense bill recently passed by Congress asks the president to abandon this Cold War thinking and support talks in January toward a full test ban when the Partial Test Ban Treaty Amendment Conference will convene in New York.

We must delegitimize the development of nuclear arms by moving toward a ban on testing them, rather than continuing by our own example to promote the glory of nuclear power status. The writer, a former director of the U.S. Arms Control and Disarmament Agency, was chief negotiator for SALT II.