WHITE HOUSE DISCOUNTS THREAT OF TRADE WAR President Reagan has reaffirmed his opposition to protectionism and his chief spokesman said trade sanctions imposed on Japan were unlikely to start a trade war. "We don't want to go down that road," Reagan was quoted as telling Prime Minister Jacques Chirac after the visiting French official expressed concern about the rising tide of protectionist sentiment in the United States. Later, White House spokesman Marlin Fitzwater defended the new sanctions against Japan and said administration officials "do not believe this will result in a trade war." "It is the first time that the United States has taken an action of this type and it is significant but it is nothing to be alarmed about," the presidential spokesman added. "We do not want protectionism ... We do not want a trade war," he said. Fitzwater said the president was forced to act in the Japanese microchip case because Tokyo had failed to fulfill "an agreement to make some corrections." Noting that there are "enormous pressures in the Congress and the land" for the United States to take a tough stand, he said, "This was a case where we felt we simply had to act." Fitzwater said the decision to impose sanctions was "well considered by this administration and not taken lightly." While the White House official held open the possibility that Washington and Tokyo will settle their trade dispute, he indicated a settlement probably would not come in time to head off the sanctions. "We are always open to negotations ... Whether it (a settlement) could occur in time to prevent this (the sanctions) from going into effect is questionable at this point," the spokesman said. The sanctions take effect in mid-April.