PROLIFERATION : U.S. Campaigns to Contain Nuclear Arms : Administration wants 25-year-old treaty to become permanent, but others balk.

The Clinton Administration, trying to bolster its campaign to prevent the spread of nuclear arms, hopes to persuade the four other nuclear powers to end production of a key weapons component.

A senior Administration official said that Russia, Britain and France have agreed to join the United States in announcing that they will no longer produce weapons-grade plutonium and uranium. The announcement is to come before the April 17 start of an international conference to renew the 25-year-old Nuclear Non-Proliferation Treaty.

But China has not yet agreed to go along.

With the United States and Russia dismantling much of their nuclear arsenals under recently ratified arms control treaties, such an agreement would have little practical effect because there is a substantial surplus of recyclable material that can provide weapons fuel. But U.S. officials believe that it could have a huge symbolic impact.

A small but determined group of non-nuclear countries is resisting U.S. efforts to make the treaty permanent, because they say it discriminates against countries that did not possess atomic weaponry when the pact took effect in 1970. The treaty bans all non-nuclear countries as of that date from joining the exclusive nuclear club.

U.S. officials hope that an agreement by the nuclear powers to stop producing bomb fuel will help persuade the holdouts to go along.

Administration strategists can count on fewer than 70 of the 86 votes needed to make the treaty permanent. But officials say 40 or 50 other nations are leaning toward approval, enough to assure passage. With Argentina’s ratification effective Friday, 171 nations and Taiwan are signatories to the treaty.

A hard-core group of 20 or so countries, including Nigeria, Indonesia, Mexico and Egypt, is against making the pact permanent, although U.S. officials say most of them appear willing to approve extension for a set period of years. When first approved, the pact had a 25-year term.

*

Most of the holdouts object to the exclusive rights granted to the United States, Russia, Britain, France and China. But Arab states, led by Egypt, also oppose indefinite extension of the pact unless Israel agrees to sign and place its nuclear program under international inspection.

Israel, which has steadfastly refused to join the pact, is widely believed to possess a substantial number of nuclear bombs.

Several potential nuclear states, including Israel, India and Pakistan, remain outside the treaty, refusing to submit to international inspection. Moreover, the inspection regime has failed to prevent signers North Korea, Iraq and probably Iran from launching weapons development programs.

Nevertheless, the pact is generally considered to be the most effective arms limitation treaty ever enacted.

(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)

Treaty on Trial

Issues involved in renewing the Nuclear Non-Proliferation Treaty:

* Treaty: The Nuclear Non-Proliferation Treaty, which took effect in 1970, prohibits non-nuclear countries from acquiring nuclear weapons. It is generally considered to be the most effective arms treaty ever.

* At Issue: An April 17 conference is aimed at renewing the treaty. The United States wants make the extension permanent.

* Obstacle: A small group of countries is resisting efforts to make the treaty permanent, saying it discriminates against countries that did not have nuclear weapons before 1970. Most nations, however, appear to favor a temporary extension for a set number of years.