The Washington Summit : Soviets Offer Strategic Missile Plan : Inspectors Would Put Tamper-Proof Seals on Warheads

After years of pronouncing the task too difficult, the Soviets appear to have come to Washington with a proposed solution to one of the toughest obstacles to agreement on drastic reductions in strategic arms: how to distinguish between sea-launched cruise missiles tipped with nuclear warheads and those armed with conventional explosives.

Yevgeny P. Velikhov, vice chairman of the Soviet Academy of Sciences and an influential arms control adviser to Soviet leader Mikhail S. Gorbachev, has suggested that, as part of the verification system, each superpower should permit inspectors from the other country to witness the final assembly of all sea-launched cruise missiles (SLCMs) and place tamper-proof seals on the warhead compartment of those armed with conventional explosives.

Then later, in challenge inspections at U.S. and Soviet ports, the seals could be checked to be sure that none of the conventionally armed SLCMs had been refitted with nuclear tips.

U.S. negotiators may have serious problems with the specifics of Velikhov’s proposal, but it was greeted as a hopeful sign: For the first time, Moscow appears to be addressing seriously one of the most difficult problems to be solved before the superpowers can complete the sweeping strategic arms reduction talks (START) pact that Gorbachev and President Reagan see as the next step in arms control.

The Soviets have been particularly concerned about the American SLCMs because they feel they can be used to launch a bolt-from-the-blue nuclear first strike on the Soviet homeland. Fired from ships and submarines lurking near the Soviet coast, the low-flying, highly accurate missiles would be so hard to detect that the Soviets would have only minutes of warning before they reached their targets.

Velikhov’s proposal is also significant, according to U.S. arms control specialists, because it appears to signal Soviet willingness to continue and extend the kind of intrusive verification procedures contained in the treaty covering ground-launched medium-range missiles signed Tuesday.

The proposal is the most detailed such formulation that has been offered to date by any high-ranking Soviet official. It was presented by Velikhov at a meeting with a group of scientists at Stanford University on Monday; details emerged Tuesday.

Shift in Soviet Position

U.S. officials had expected that a new Soviet proposal would be presented during the summit. Speaking to reporters Dec. 3, Arms Control and Disarmament Agency Director Kenneth L. Adelman predicted that the Soviet armed forces’ chief of staff, Sergei F. Akhromeyev, would carry a new SLCMs proposal to Washington this week.

Velikhov’s verification proposal also marks a shift away from Moscow’s basic position on the weapons: Citing the difficulties of distinguishing between the two versions of the weapons, the Soviets in the Geneva strategic negotiations have been calling for a ban on all cruise missiles able to strike targets more than 370 miles away.

In July of this year, they proposed that the superpowers cap their arsenals of nuclear-armed SLCMs at 400 apiece and ban their deployment on surface ships.

Washington has argued in those negotiations that there should be no limits on the SLCMs because it is too difficult to verify limits on nuclear SLCMs as distinct from those with conventional TNT warheads.

The Navy has told Congress that it plans to put about 3,400 long-range cruise missiles aboard its ships and submarines by the mid-1990s and about 600 shorter-range cruise missiles designed to attack ships. Just over 750 of the U.S. SLCMs would be armed with nuclear weapons.

Enhance Stability

While Moscow has expressed concern about SLCMs, many American experts counter that the missile’s slow flight time compared to that of larger intercontinental ballistic missiles--and the fact that the other side’s SLCMs would be relatively invulnerable aboard submarines--makes it a weapon whose survivability would enhance stability and would not pose a realistic first-strike risk.

The Soviets are developing two long-range cruise missiles of their own, the 1,900-mile range SS-NX-21, assumed to be armed with nuclear weapons, which the Soviets are believed ready to deploy, and a larger cruise missile some years from deployment called the SS-NX-24.

Moscow already has deployed 942 short-range cruise missiles on its ships and submarines, according to the Natural Resources Defense Council.