Nuclear Inspections Move U.S., Soviets Toward START Verification Procedures : Arms: Groundwork laid for coming treaty, but differences remain. Compromise is sought in Geneva.

Early this month, the submarine Tennessee moved alongside a pier at Kings Bay, Ga., where a crane lifted out one of its 24 Trident 2 missiles--the most modern and secret nuclear weapon in America’s arsenal--for inspection by Soviet military experts.

A 12-man Soviet team was permitted to board the submarine and peer from the deck into the empty missile tube, then to follow the missile as it was carried to a disassembly facility, where its payload was removed and transferred to a room with only one door.

The Soviets were asked to stand at the door while the nose cone was taken off. The warheads were hidden under an opaque, rubberized shroud that masked the details of the Trident’s design.

When the Soviets entered the room, they could count eight bulges under the shroud--the tips of eight warheads, the maximum that would be permitted for each missile.

Such access to U.S. weapons, which as recently as a few months ago was granted to only a few U.S. officials with top-secret clearance, is now being given routinely to Soviet specialists as part of an effort to develop verification procedures for the Strategic Arms Reduction Talks (START) treaty that is in the final stages of negotiation.

The Soviets have done the same for American inspectors.

U.S. officials hope that this “try-before-buy” approach will help the U.S. On-Site Inspection Agency (OSIA) and its Soviet counterpart to hit the ground running later this year when START, along with a companion treaty designed to reduce conventional forces in Europe, is expected to be signed.

The United States has devised similar procedures to enable the Soviets to verify payloads in two other instances--a land-based MX intercontinental missile in a Wyoming silo, in April, and B-1 bombers at Grand Forks, N.D., in May.

In similar proceedings, at Murmansk on June 12, the Soviets showed U.S. inspectors a modern SS-N-23 missile taken from a Delta IV submarine. Earlier, they had unveiled a giant SS-18 in Kazakhstan, and Bear-G and Bear-H bombers at an air base south of Kiev.

If the arms-reduction treaties are signed, such inspections will become routine. START is expected to limit the two great powers’ arsenals to 6,000 “accountable” nuclear weapons, about 4,900 of them missile warheads.

But U.S. officials say that neither side has accepted fully the other’s approach to verification, and representatives of the two nations are now back in Geneva seeking to work out a compromise on their differences.

Members of the On-Site Inspection Agency were present for both inspections in the Soviet Union. This is the Pentagon-run agency created two years ago to verify Soviet compliance with the Intermediate-range Nuclear Forces (INF) agreement to eliminate medium-range missiles in Europe.

OSIA staff members inspect Soviet facilities and are present to verify the destruction of weapons. They also escort their Soviet counterparts when they come to the United States on such missions.

Last week, OSIA was assigned verification duties for the new arms control agreements that are expected to be signed this year--START and the treaty on Conventional Forces in Europe--plus more technically demanding agreements to limit underground nuclear tests and to destroy chemical weapons stockpiles.

OSIA has overseen the INF agreement, largely without a hitch, for two of its three years. So far, OSIA officials have made 352 inspections, verifying both the presence and the destruction of more than 90% of Soviet INF missiles--and 85% of Soviet treaty-limited items including launchers, missiles and other equipment.

In the same period, Soviet inspectors have witnessed the elimination of 62% of U.S. missiles--and 63% of all treaty-limited equipment.

Brig. Gen. Ronald LaJoie, the OSIA chief, said the United States has been “generally happy with the inspection procedures we’ve worked out.” He said he believes that the two sides “can build on the INF record.”

Each side has complained only about a dozen times of “ambiguities” found in their inspections. These can range from relatively minor incidents--for example, a missile stage that was mistakenly made a bit smaller than specified in blueprints--to a major dispute over Soviet refusal to allow U.S. inspectors to use an X-ray machine to scan three missile stages emerging from a plant at Votkinsk in the Ural Mountains.

The Soviets insisted that the X-ray equipment was not within the agreed limits, fearing that it might scan more of the missile than necessary and enable the Americans to obtain technical secrets such as the grain size of its propellant.

But they did permit the Americans to examine the missiles as they had before the X-ray equipment arrived. And it took a diplomatic protest from Secretary of State James A. Baker III to Soviet Foreign Minister Eduard A. Shevardnadze to get the “ambiguity” resolved. Eventually, the X-ray device was installed.

Other, more sensational accounts, including a report that a Soviet missile train “barreled” through a crowd of U.S. inspectors and that Soviet guards drew weapons to force the Americans back, have been denied by OSIA officials.

A much more serious INF compliance issue, not involving OSIA, had to do with the sale of 48 Soviet SS-23 missiles, which are barred by the INF treaty, to the East Germans, Czechoslovaks and Bulgarians.

Moscow said it had not disclosed the existence of these missiles because they had been transferred to the other countries before the treaty went into effect.

OSIA says that all 239 of the SS-23s once held by the Soviets have now been destroyed. But suspicious U.S. officials, many of whom believe that the Soviets acted in bad faith in failing to disclose the transferred weapons, are continuing to press Moscow for a better explanation of the episode in order to prevent similar problems with future treaties.

U.S. officials say that on-site inspection of nuclear underground blasts and monitoring of the destruction of chemical weapons will be sufficiently different from INF procedures to require new regulations. But many of the basic logistics, counterintelligence, airlift and communication facilities and functions will be the same as for the present inspection mission.

To meet the new responsibilities, OSIA will probably add about 780 people to its present staff of 220. And its $40-million annual budget will soar to $200 million or more.

But that is only a small fraction of the price of verification. It does not include costs that could multiply the total several times over. Private experts say the overall cost of verification could be as high as $1 billion a year.

Included in this are the salaries of military personnel, who at present make up two-thirds of the OSIA force, and the cost of FBI surveillance of Soviet inspectors.