REAGAN TO ANNOUNCE DECISION ON JAPAN SANCTIONS President Reagan today is to announce a decision on tough new tariffs on Japanese exports to retaliate for what he calls Japan's failure to end its unfair practices in semiconductor trade. The 100 pct tariffs are to be imposed on 300 mln dlrs of Japanese goods recommended for curbs by a special panel of experts headed by the U.S. Trade Representative's Office. Reagan announced last March 27 he would impose the tariffs on certain goods taken from a list that ranged from computors and television sets to power tools and photographic film. The panel this week winnowed through the list of the some 20 products and sent their recommendations yesterday to Santa Barbara, where Reagan is vacationing. In his March annoucement, Reagan said "I am committed to full enforcement of our trade agreements designed to provide American industry with free and fair trade opportunities." He added the tariffs would be lifted once Japan honored the pact it signed last year to end dumping semiconductors in world markets and opened its home market to U.S. products. U.S. officials said Japan had done nothing since the March announcement to alter Reagan's plan to invoke the sanctions. White House spokesman Marlin Fitzwater said yesterday: "we do not want a trade war, but we feel that this is the kind of action that requires meaningful action." Reagan's move follows steadily rising U.S. trade deicits, with last year's hitting a record $169.8 billion. About one-third of the deficit is in trade with Japan. Congress is weighing a trade bill to force the president to retaliate in certain cases of unfair trade practices. He has opposed the legislation, saying it would prevent negotiated solutions to trade disputes and, in any case, that existing law was adqeuate to end unfair trade practices. Trade experts say his tough action against the Japanese was as much to penalize the Japanese as to show Congress he did not need any new trade legislation. The Japanese have complained that they have been honoring the semiconductor pact, but that it would take time before the results showed up. U.S. officials, however, have said their monitoring of Japanese semiconductor shipments to East Asian countries and Western Europe showed no letup in the dumping and that the Japanese home markets remained shut to American exports. Japan has said that if Reagan imposed the tariffs, it would file a complaint with the General Agreement on Tariff and Trade (GATT). It said hoped GATT would find the U.S. retaliation had violated the regulations of the global trading group and would approve compensation or Japanese retaliation. U.S. officials have said they did not think Japan would retaliate because it had too much to lose in any trade war with the United States.