Nunn Asks U.S.-Soviet ‘Fail-Safe Review’ to Avert an Unwarranted Missile Launch : Military: Georgia senator says the danger of accidental firings ‘has not gone down.’

The chairman of the Senate Armed Services Committee proposed Saturday that the United States and Soviet Union undertake an unprecedented overhaul of the safeguards they have in place to protect against an accidental or unauthorized launch of nuclear weapons.

Sen. Sam Nunn (D-Ga.) said he will make a formal proposal soon to Defense Secretary Dick Cheney to begin a sweeping review of existing mechanisms adopted by the armed forces to ensure the security of the nation’s nuclear weapons.

“What I’d like to do is see President Bush challenge the Soviets to do the same thing,” Nunn said in an interview with The Times. “If they did that, it could be one of the most important arms control agreements on one sheet of paper we ever had.”

He called such an evaluation a “fail-safe review,” a reference to a best-selling 1962 novel, “Fail-safe,” about a U.S. nuclear bomber that initiates a superpower nuclear exchange because it could not be called back once it had begun its mission.

As a first step, Nunn said, the Pentagon should overrule longstanding objections on the part of the military services to developing new mechanisms that would allow U.S. missiles to be destroyed or called back after they have been launched.

Now that political changes in the Soviet Union and Eastern Europe appear to have decreased the threat of an intentional nuclear conflict between the superpowers, Nunn said Washington and Moscow should work together to reduce the possibility of unintended nuclear exchanges.

“Although the whole danger of war has gone down . . . the danger of unauthorized or accidental (launches), in my opinion, has not gone down,” Nunn said.

The proposal comes at a time when U.S. experts are expressing increasing concern about the safety and security of the Soviets’ far-flung nuclear weapons, some of which are located in areas that are the scene of nationalist and ethnic uprisings.

Nunn echoed the views of many experts who maintain that the Soviets have not placed sufficient safety mechanisms on their nuclear arsenal.

“It might be we can decide there’s certain technology we have that we’d like the Soviets to have,” Nunn said. “I’m not comforted by the fact that they don’t have good enough technology to put sophisticated fail-safes on their systems.”

Nunn said he already has discussed the idea with Gen. Colin L. Powell, chairman of the Joint Chiefs of Staff, and other senior military officials, some of whom have resisted calls for further safeguards.

“If they don’t do it then, I will go to the (Senate) Rules Committee and try to get enough people over there to do it myself,” warned Nunn, a leading congressional expert on national security issues.

But the senator said that he would prefer that the Pentagon direct the investigation with congressional oversight, using experts who are not now responsible for the safety of nuclear weapons.

Since becoming chairman of the Senate Armed Services Committee, Nunn has been active in promoting superpower efforts to defuse crises that could lead to nuclear war. For example, he successfully pressed the Reagan Administration to establish “nuclear risk reduction centers” that allow Moscow and Washington to exchange key military data.

In 1988, Nunn proposed that the Pentagon consider scaling back plans for the Strategic Defense Initiative program, the space-based missile defense system known as “Star Wars,” so that it would be capable only of shooting down a small number of missiles fired accidentally.

Pentagon officials in recent months have placed new emphasis on nuclear safeguards, touting the B-2 bomber program, for instance, as a slow-flying nuclear weapons system that could be recalled if a nuclear strike order were rescinded.

At the same time, however, American and Soviet experts have complained that the U.S. military is facing increasing risks that its nuclear weapons could be fired without authority.

Of the U.S. military services, only the Navy has not introduced “permissive action links,” or PALs, on its nuclear weapons. The PALs are special mechanisms designed to ensure that nuclear weapons cannot be launched except by presidential order.

As the Navy deploys a new generation of sea-launched cruise missiles on many of its smaller ships, some independent experts fear that more sailors will have access to the weapons and could launch one without presidential approval.

The Navy has consistently resisted proposals to add additional safety latches to prevent unauthorized launches, arguing that such restrictions are unnecessary and would reduce the deterrent effect such weapons have against an offensive strike by another nation.

“It’s a good idea, and it should concentrate on naval weapons,” Barry Blechman, director of the Washington-based Henry L. Stimson Center, said of Nunn’s proposal. “There’s absolutely no excuse for them not to have PALs. It’s an outrage.”

At the same time, both the Air Force and the Navy have said that the development of destruct mechanisms on missiles in flight would make them vulnerable to an adversary’s attempt to neutralize a U.S. nuclear strike.

“In this kind of age of technology, to have no fail-safe destructive mechanisms on missiles does not make sense to me,” said Nunn. “I think we ought to be seriously pursuing that.

“The argument’s always been (that) if you can do that, the adversary might find out how to do it and you lose,” he said. “But if we’re trying to put up a dome over the world with ‘Star Wars,’ the least we can do is figure out a way” to develop a secure link to missiles that would interrupt their flight.

Peter D. Zimmerman, a Washington-based physicist and consultant on arms control issues, called Nunn’s fail-safe review “overdue.”

Speaking of the missile-destruct mechanism, however, Zimmerman said, “That’s been an idea whose time may not have come--or at least the time to explore whether it’s technically do-able without compromising the security of the system.”