February 11, 1984

As Soviet leader, Yuri V. Andropov encountered major problems with the West and with a stagnating economy at home. An obituary, page 9. MOSCOW, Feb. 10 - The Soviet leadership announced today that Yuri V. Andropov died Thursday, less than 15 months after he succeeded Leonid I. Brezhnev as General Secretary of the Communist Party. He was 69 years old. The two-paragraph announcement was read on radio and television at 2:30 P.M. (6:30 A.M. New York time) and was repeated throughout the day. It was followed by a series of bulletins on the causes of death and on arrangements for a funeral on Tuesday.

With only a few hours' notice, more than 400 American citizens, protected by United States marines and Druse militiamen, were evacuated from Beirut today. Britain also evacuated hundreds of its citizens, and Italy prepared to do so. The American Embassy had received many appeals from American citizens for transport out of Beirut, where they have been trapped by fighting. It announced this morning that ''because of the unsettled conditions in Lebanon'' it would evacuate any Americans or Lebanese in the process of taking up American citizenship.

NewsAnalysis MOSCOW, Feb. 10 - Yuri V. Andropov's death put an end to the shortest period of rule in Soviet history, if Georgi M. Malenkov's week as titular Communist Party chief after Stalin's death can be overlooked. But neither the worsening Soviet-American chill that marked Mr. Andropov's 15 months as leader nor the changes he set in motion through the Soviet Union's ponderous economic system and bureaucracy are considered likely to be altered anytime soon, no matter who succeeds him. The chief reason, most diplomats agree, is that Mr. Andropov's economic experiments, his crackdown on corruption, and even his hard line in foreign relations found the support of a populace yearning for a tough ''khozyain,'' or boss - and, more important, the support of powerful men and institutions. Ending the Stagnation Power brokers like Defense Minister Dmitri F. Ustinov, now arguably the most powerful man in the Politburo, or Foreign Minister Andrei A. Gromyko, and institutions like the military, the K.G.B. or elements that support change in the state planning bureaucracy, had apparently welcomed Mr. Andropov's drive to stir the dormant economy and end the stagnation that had settled over the bureaucracy during the Brezhnev years.

The Long Island Lighting Company defaulted yesterday on its partnership agreement with four other New York State utilities that are building the Nine Mile Point 2 nuclear power plant on the shore of Lake Ontario. The company said that it had missed a $1.1 million payment due Thursday and that it would spend no more on the plant, which is still at least two years from operation, at an estimated cost of $4.2 billion for completion. Lilco has invested about $500 million in the project since 1975, when it agreed to buy 18 percent of the reactor. This year its share would have been $180 million. The utility is struggling to raise cash because of its troubles with the Shoreham reactor, which it is building alone on Long Island.

The appointment of Konstantin U. Chernenko today to head Yuri V. Andropov's funeral commission marked at least a partial triumph for a veteran Communist who only 15 months earlier seemed to have reached the end of his political career. Whether the appointment suggested that Mr. Chernenko had been tapped to succeed Mr. Andropov, or whether it was given him on the strength of his position as the second-ranking secretary, was likely to become clear only when the Central Committee named a new General Secretary. A Feat of Survival But the fact that Mr. Chernenko would be the one to supervise the burial of his former rival was in itself a feat of political survival not without an element of irony. Mr. Chernenko, now 72 years old, had been the closest aide to Leonid I. Brezhnev and the clear choice of Mr. Brezhnev's entourage to succeed the late leader. But Mr. Andropov had outmaneuvered them all, and on Nov. 12, 1982, Tass, the official press agency, announced that Mr. Chernenko himself had nominated his rival to become the new Soviet chief.