The United States, Soviet Union and the 13 other nations, East and West, that supply the world's nuclear equipment and materials yesterday made public a set of agreed rules designed to block the spread of atomic weapons.
The nuclear supplier nations, which negotiated the arrangements in a series of semi-secret meetings in London, simultaneously submitted their joint sales guidelines to the International Atomic Energy Agency in Vienna, according to State Department officials. The document is not a formal international agreement, but is the next thing to it, since each of the 15 countries undertakes to abide by this set of rules in selling atomic supplies, and unanimous consent is required for any changes.
The agreed guidelines are the first publicly acknowledged product of the "suppliers' club" meetings, which began in April, 1975, in the wake of international concern spurred by India's atomic explosion of a year before.
The meetings initially were highly confidential because France - a key supplier nation - threatened to walk out if the discussions became known.
The international rules for atomic sales published yesterday are less stringent in some respects than rules formulated individually by several of the important nations involved, including those for the United States now pending in late stages of consideration on Capitol Hill.
However, Joseph S. Nye, the State Department's nuclear proliferation expert, said that publication of the guidelines by the nations involved represents an important step, and that moves toward agreement on more stringent rules are anticipated later this year.
The ground rules cover the transfer of all nuclear technology, plant and material covered in a seven-page "trigger list," adopted unanimously, which includes reactors, enrichment and reprocessing plants, enriched uranium and other sensitive nuclear material. In order to purchase any of these items, an importing country must agree:
To provide "formal governmental assurances" that the material or facilities will not be used to produce "any nuclear explosive device," whether a weapon or a supposedly "peaceful" explosion.
To place the material or facilities under "effective physical protection" to prevent theft or sabotage. The levels of protection required, depending on the sensitivity of the item, have been agreed by the supplier nations.
To accept international inspection by the International Atomic Energy Agency of the material or facilities being imported and any similar items produced locally using the same type of design.
To not retransfer supplies without requiring the same ground rules which applied to the original sale and, in the case of major sensitive items, the permission of the original supplier.
In the case of a suspected or obvious violation of the guidelines, the document calls for prompt consultation among the supplier countries about possible spactions.
Each of the suppliers agreed not to undercut any supply cutoff or other potential sanction while these contacts are taking place - a provision which is close to being an automatic worldwide cutoff of nuclear materials, at least for a time, in case of a nuclear explosion or other violation.
Negotiation of this last provision, according to Nye, was the major accomplishment of the Sept. 21 suppliers' meeting in London, when agreement on the guidelines was obtained.
The Soviet Union and some other nations have been pushing for the adoption of "full-scope safeguards" under which a recipient nation would be required to permit international inspection of all its nuclear facilities - no matter how or when acquired.
The pending U.S. legislation would require "full-scope" safeguards as a condition of nuclear purchases from the United States 18 months after the bill becomes law, unless the President waives the requirement.
According to Nye, only five "non-nuclear weapons" nations now have facilities which are not subject to inspection. These are India, Israel, South Africa, Egypt and Argentina, with the latter two not considered to be serious problems.
Nye called publication of the guidelines by the supplier nations "a move forward toward full scope safeguards."
The seven major nuclear supplier nations which began discussions in London in 1975 are the United States, Soviet Union, France, Britain, Japan, West Germany and Canada.
They have been joined by eight countries which are less important suppliers or on the threshold of nuclear exporting - Poland, East Germany, Czechoslovakia, Belgium, the Netherlands, Italy, Sweden and Switzerland.