U.S. Gives Soviets Proposals to Block Nuclear Exports : Arms control: Experts will brief republic leaders next week on ways to keep arsenals secure.

The United States, expressing concern that Soviet nuclear weapons could be sold to hostile forces overseas, has made “very, very concrete proposals” to four nuclear-armed Soviet republics on ways to block any unauthorized exports of weaponry or technology, a senior State Department official said Friday.

Reginald Bartholomew, undersecretary of state for international security, said in an interview that control of weapons exports is one of the most critical items on the agenda of Secretary of State James A. Baker III, who leaves today for a visit to Russia and four other Soviet republics.

Bartholomew said the United States has specific ideas on how an export-control system should be structured and what safeguards should be in place to prevent the transfer of weapons technology. These will be spelled out to leaders of the republics in meetings next week.

Baker, in a speech at Princeton University this week, said the Administration will send a team of experts to brief republic leaders on means of stemming proliferation and will promote programs to employ Soviet nuclear scientists in peaceful pursuits.

Despite repeated statements of concern about the safety of Soviet nuclear weapons, the Bush Administration does not yet have detailed plans behind its general offer to help the post-Soviet republics bring their inherited nuclear arsenals under control, officials said.

U.S. officials are waiting to hear how republic leaders plan to transport, store and dismantle the 27,000 nuclear weapons on their soil. It then will offer technical aid and money to help with the program.

“Basically we need to learn more from them what their plans are and where they’re going,” a top Administration official said. “But we are not going there with a detailed blueprint saying here’s what you should do and how and when you should do it.”

Congress earmarked $400 million in the current Pentagon budget to aid the crumbling Soviet Union in destroying its stockpile of nuclear, chemical and biological weapons. But lawmakers left it up to the Bush Administration to decide how the money should be spent.

Officials said Friday they had no idea yet how they would spend any of the money.

U.S. officials opened general discussions on nuclear safeguards with the republics--as well as the Soviet central government--in meetings in Washington in late November.

In those and other discussions, American experts have suggested that the weapons could be transferred to well-protected central locations, inventoried, then sealed to guard against tampering as the first steps of the dismantling process. The weapons could then be broken down and their explosive and radioactive materials stored in secure depots.

Officials said Friday that they hope to identify the “bottlenecks” in the Soviet system that could slow the destruction of nuclear weapons and provide expertise and cash to help unclog them.

That might entail, for example, using some of the $400 million to provide secure transport or storage containers or even to construct a dismantling facility along the lines of the Department of Energy’s Pantex plant, where U.S. nuclear weapons are retired, officials said.

Thomas B. Cochran, senior scientist at the Natural Resources Defense Council, said that the Administration is approaching the question of Soviet weapons destruction too passively. Cochran, who is leading a group of private and government nuclear weapons experts to Russia and Ukraine beginning Sunday, said the U.S. government is waiting for the other side to make proposals before offering any advice or expertise.

“The Administration is throwing out a good line, saying we’ll help them, but we’re waiting for them to come to us with a plan,” Cochran said. “But the real issue is, why don’t you propose some bilateral initiatives that would move this process along?”

His group, which includes nuclear scientists from American universities and technicians from Department of Energy nuclear weapons laboratories, will meet with their counterparts from the two most important Soviet republics to begin to discuss the “technical nitty-gritty of weapons dismantlement.”