Ukraine Votes to Close Chernobyl Plant : Soviet Union: New signs emerge of Kremlin attentiveness to local demands.

Lawmakers in the Ukraine voted overwhelmingly Wednesday to shut the Chernobyl power plant, site of the world’s worst nuclear accident, as ethnic groups in the Soviet Union from the Baltic Sea to the Black Sea pressed their demands on Moscow.

In a sign of the new Kremlin attentiveness to the desires of increasingly combative local authorities, Soviet President Mikhail S. Gorbachev agreed with Russian Federation President Boris N. Yeltsin to form a joint panel of experts to work out the principles of a future market economy.

That development, reported by the Interfax news agency, could mean Gorbachev is now willing to accept the more radical recipes for economic change advanced by Yeltsin. Or he may seek to win the support of the popular Russian Federation leader for his own economic and social policies.

Interfax, however, said the group would work on the basis of the 500-day transition plan formulated by the Russian Federation’s government, with Yeltsin’s approval, which places heavy emphasis on denationalization and extension of private property.

In the Ukraine, lawmakers by a vote of 363 to 5 gave their government until Dec. 1 to come up with a program for shutting the Chernobyl power station, where a reactor explosion in April, 1986, killed at least 31 people and sent a cloud of radioactivity around the globe.

The legislators also declared their republic an ecological disaster area more than four years after the accident, according to the report from Kiev distributed by the non-governmental information agency Rukh Press International.

The Ukrainian Supreme Soviet asked the government to report on the feasibility of shutting down all nuclear power stations in the republic, but Konstantyn Masyk, the deputy prime minister, said it will take 15 years to find an alternate power source for the 15 nuclear plants now on the line in the Ukraine.

In Georgia in the Transcaucasus, recent demands of nationalists have been purely political, and they called off a crippling railway blockade Wednesday after Communist leaders agreed to compromise on demands for multi-party elections later this year.

The compromise should allow newly organized parties to take part in the elections scheduled for October, and thus to challenge the Communists, protest leaders said.

Faced with such increasing restiveness on the Soviet periphery, the Gorbachev leadership has floated the idea of a new “union treaty,” to be written by December, that would create a voluntary union of “sovereign states” with enhanced local powers.

The concept became more concrete Wednesday when Estonia’s prime minister, Edgar Savisaar, signed a pioneering treaty in Moscow putting Estonia’s Ministry of Internal Affairs, which is responsible for law enforcement, directly under local control and financing.

By the terms of the treaty, Estonia “will take upon itself the entire responsibility of public order in the republic,” the independent Estonian News Service reported.

The Estonian News Service said the treaty was signed for the central government by Interior Minister Vadim V. Bakatin, a member of Gorbachev’s Presidential Council, an indication that its formulation had top-level support.

Savisaar, however, predicted that Bakatin will be criticized for the agreement, which ends unbroken nationwide control by Moscow of the militsia, or police force, a longtime given in Soviet life.

Yeltsin said an alternative draft for a “union treaty” will be presented on behalf of the Russian Parliament in the next day or two.

The Russian draft, Yeltsin told the Latvian legislature, would give few powers to central government authorities, whereas Gorbachev has called for wide spheres of the nation’s life to remain in the hands of Moscow-based officialdom.