Washington — Sen. Charles H. Percy, chairman of the Senate Foreign Relations Committee, is calling for a superpower summit in 1982. The Illinois Republican, who held several hours of talks in Moscow with top Soviet leaders a year ago, says that Secretary of State Alexander M. Haig Jr. agrees that under the right conditions a US-Soviet summit meeting would be a ''practical goal to shoot for'' next year.
In a breakfast meeting with reporters Nov. 24, Senator Percy argued that to allow 1982 to pass without a summit would be ''dangerous.'' As the senator sees it, a summit meeting would serve the purpose of helping to prevent the kind of miscalculation on the part of the two superpowers which could lead to war. In answer to questions, he added, however, the US should not go to any such meeting unless it was carefully prepared and stood a reasonable chance of success.
Asked what he thought the chances were for a summit meeting taking place next year, Percy replied ''50-50 or better.''
Percy said that his experience in dealing with Soviet leaders on several occasions had led him to believe that the US must be represented at summit talks with the Soviets by ''someone who's really tough.'' The senator described President Reagan as a leader well qualified to fill that role; he said that Reagan, a man who ''doesn't blink,'' was also a man with whom one can reason on matters such as arms control. Soviet President Leonid Brezhnev, in Percy's view, is a leader committed to obtaining arms-control treaties with the United States.
Percy indicated that the Soviets would rather deal with a leader who is tough but consistent than with a leader who seems accommodating but vacillates. He said that the Soviet leaders preferred dealing, for example, with Presidents Ford and Nixon to dealing with President Carter.
The senator thought that Reagan's ''sense of toughness'' would appeal to President Brezhnev. He added that in meetings with the Soviet leaders, Reagan would be ''as brilliant . . . as he's been in every other meeting he's had'' with foreign leaders.
Percy did not appear to be discouraged by President Brezhnev's seemingly negative response to Reagan's call for deep mutual cuts in medium-range nuclear missiles.
State Department officials, however, were cautious in their evaluation of remarks which President Brezhnev made on Nov. 23 during his visit to West Germany. Brezhnev appeared to reiterate an offer which he had in Berlin in 1979 to freeze the deployment of new medium-range nuclear weapons in Europe.
The reaction of one State Department official to the freeze, or moratorium, proposal was this: ''The Soviets have had a one-way arms race and then they say, 'OK, everybody freeze.' That just won't do.''
In reaction to Percy's call for a US-Soviet summit, another State Department official said: ''That would require some movement on the issues . . . and improvement in the atmosphere.''
In his remarks in West Germany, Brezhnev did offer as a gesture of goodwill to reduce ''a certain portion'' of the Soviets' medium-range nuclear weapons based in the European part of the Soviet Union. At first glance, State Department officials seemed to feel that the Brezhnev proposals were either not new or so vague as to be almost meaningless. But White House Counselor Edwin Meese III said in an interview with a cable news network that he thought the Brezhnev proposals were a ''step in the right direction . . . a hopeful sign that they, too, will negotiate in good faith.''
Negotiations between the US and the Soviet Union on medium-range nuclear weapons are scheduled to begin in Geneva on Nov. 30. Talks concerning long-range nuclear weapons could begin early next year following a meeting scheduled for late January between Secretary Haig and Soviet Foreign Minister Andrei Gromyko.
Some Reagan administration officials have been concerned that such talks - and an eventual summit meeting - might undermine support for the US defense buildup and create expectations among the American people that would be dashed by subsequent Soviet actions. In their view, the whole process of US-Soviet detente in the early 1970s lead to unrealistic expectations on the part of many Americans. At the same time, the officials realize that arms-control talks and summitry could help defuse West European opposition to a defense buildup by the US and its NATO allies.
In his talk with reporters, Percy said he thought that the Nov. 18 Reagan speech on arms control had provided West German Chancellor Helmut Schmidt with a ''tremendous edge'' in his talks with President Brezhnev and had helped to undercut the antinuclear movement in West Europe.