GENEVA (AP) _ The Soviet Union has named Yuri Nazarkin, a Foreign Ministry official, as its new chief delegate at the 40-nation Geneva Conference on Disarmament, the Soviet ambassador said Monday.

It was the second major change in Soviet arms negotiators since last weekend.

Although the Soviet Union has not confirmed it, U.S. officials in Washington said over the weekend that First Deputy Foreign Minister Yuli Vorontsov will succeed Viktor Karpov as the Kremlin's chief negotiator at the U.S.-Soviet arms talks in Geneva.

Soviet Ambassador Yevgeny Makeyev told reporters that Nazarkin will replace Viktor Issraelyan, who will return to Moscow.

He declined to give a reason for the change or to comment on the Washington report that Vorontsov will succeed Karpov.

There is very little, if any, connection between the 40-nation disarmament conference and the U.S.-Soviet negotiations that are to resume Thursday.

Makeyev said Nazarkin has been heading the Foreign Ministry's department on the peaceful use of atomic energy and outer space.

The 40-nation conference, currently in recess, is the world's main multilateral arms control forum. Major topics include a nuclear test ban and drafting of an international convention to ban chemical weapons.

The full conference reconvenes Feb. 3, but a chemical weapons panel began work Monday.

Delegates to that panel resumed negotiations on a pact that would ban the production, stockpiling and use of chemical weapons.

The closed session follows informal talks last November and December that Soviet and Western officials said brought progress, particularly on which chemicals the ban should cover.

Soviet chief delegate Viktor Issraelyan said then the Soviets had accepted as a basis for negotiations a British proposal providing for international checks of production sites suspected of violating a future ban.

The British text, presented in July, would give parties only limited rights to refuse such inspections, but Western sources said changes sought by the Kremlin would make the plan virtually meaningless.

A more stringent U.S. draft on verifying compliance was rejected by the Soviet Union in 1984.

Issraelyan also said that Moscow had proposed to the United States a bilateral moratorium on production and deployment pending agreement on an accord. He said U.S. plans to resume chemical arms production this year threatened to spur the arms race.

Negotiations on a global convention against chemical weapons have been under way since 1968.

The chemical weapons committee, with British Ambassador Ian Cromartie as chairman, will present its report to the full conference when it reconvenes. .

Both Soviet and Western officials have said an agreement in principle could be reached this year.