Two days of intense talks between President Reagan and Soviet leader Mikhail Gorbachev led to several surprises, but on the central issue of reducing arms, the summit "has not produced anything" concrete, as Secretary of State George P. Shultz put it yesterday.

As a result, the superpowers remain essentially where they were before Geneva, in the midst of ambitious programs to modernize their nuclear weapons and delivery systems and -- despite professed willingness to cut their arsenals deeply -- far apart on all proposals for negotiated reductions.

At the summit, Gorbachev stuck firmly to his insistence that Reagan compromise on his Strategic Defense Initiative (SDI) as a prelude to other arms control agreements, and Reagan stuck just as strongly to his dream of a strategic defense, supported by publicized encouragement from his defense secretary, Caspar W. Weinberger, to resist the temptation to make concessions. The result was an impasse on arms control.

In their communique -- something White House officials had said just a few days ago would not be issued after the summit -- the two leaders announced that they had "agreed to accelerate the work" at the Geneva arms negotiations, but there was no hint that they had agreed on any concrete basis for such acceleration.

The communique -- labeled a joint statement -- did note that on two subjects, the possibility of reducing offensive nuclear arsenals by 50 percent and a suggested "interim agreement" on shorter-range weapons based in Europe, there was "common ground," and the document called for "early progress" on both.

But as a reminder of the difficulties impeding such progress, the communique repeated, in slightly changed terms, the goals set out last January, when the current Geneva talks were set up: "to prevent an arms race in space and to terminate it on earth, to limit and reduce nuclear arms and enhance strategic stability."

The Soviets have said repeatedly that these three are interrelated, and that an arms race in space can only be prevented if the United States agrees not to develop a "Star Wars" defense. Reagan apparently tried but failed to persuade Gorbachev that his SDI is really a good idea. Star Wars, it appears, will have to be the closing card played in any arms deal -- if it is ever played at all.

So the results of the summit were far from the "statement of principles" or even the "guidelines" or "roadmap" for the Geneva talks once considered to be the summit's arms control goal.

Indeed, none of the arms control steps rumored in recent weeks as possible achievements at the summit actually came to pass. There had been discussions about extending both superpowers' willingness to continue to respect the limits on nuclear arms imposed by the unratified SALT II treaty, but this was not mentioned in yesterday's statements in Geneva. Nor was there any expression of continued support for the 1972 Antiballistic Missile (ABM) Treaty.

Only on one issue was there a hint of new flexibility -- the reduction of intermediate-range nuclear forces (INF), the controversial American Pershing II and ground-launched cruise missiles and the Soviet SS20s.

Before the summit, some U.S. officials had welcomed as promising a Soviet offer last month to freeze intermediate-range nuclear forces. But the initial Soviet proposal tied a freeze to a plan for future reductions of those missiles that was not appealing to U.S. officials.

Yesterday's joint statement called for "early progress" on "the idea of an interim INF agreement," a formulation that could indicate the Soviets are no longer tying future reductions of the European-based forces to an "interim" freeze.

One new item turned up in the joint statement: the call for a study of "centers to reduce nuclear risk" that two U.S. senators, John W. Warner (R-Va.) and Sam Nunn (D-Ga.), have pushed both in Washington and Moscow. Reagan and Gorbachev also "took satisfaction" in the recent upgrading of the U.S.-Soviet hotline, an idea originally pressed within the Reagan administration by Weinberger.

Perhaps the clearest source of pressure to make more progress on arms control was the two leaders' agreement to hold another summit meeting as early as next year. Before then, both Reagan and Gorbachev could come under great pressure to make more progress.

A second summit without concrete achievements in arms control might not go down so well in either country, or among allies in Europe, particularly America's.

Unless early progress is made, both countries will soon be deploying new weapons that could complicate efforts to reduce offensive arms.

The Soviets are deploying one new intercontinental missile and are building a second (a violation, if it is deployed, of SALT II).

The United States is proceeding with production of the MX, and development of the Midgetman land-based, mobile missile, and a new, highly accurate submarine missile, the D5.