The Reagan administration is again trying to place limits on academic research. A White House senior interagency group is drafting a national policy to bar visiting scientists from Warsaw Pact nations and China from using supercomputers.

Supercomputers, with their tremendous capacity for processing information, can solve in one day mathematical problems that take conventional computers months or years. They are currently manufactured only in the United States and Japan.

The sudden concern of the White House was prompted by the decision to locate four of these goliaths at universities for use by the academic community. The administration's plans have already affected contract negotiations between the universities and the National Science Foundation, which is administering the multimillion-dollar project.

The University of California at San Diego has agreed to abide by the policy when it is promulgated. Princeton University has also agreed to adhere to the policy, but may withdraw if the policy infringes on academic freedom.

Cornell University and the University of Illinois negotiated with NSF contracts that have no restrictive language. Once the Reagan administration announces a new policy, however, they may be compelled to renegotiate.

Because of national security concerns, the administration understandably wants to keep knowledge about supercomputers from the Soviet Union. The Soviets lag behind the West in computer technology and it is in our interest that they remain so. Barring access to the machines by foreign scientists, however, is seriously misguided.

The Department of Defense is concerned that foreign scientists will gain insights about how to build supercomputers by running programs on them. Computer experts generally agree that learning how to build supercomputers by using them is roughly equivalent to understanding how a television works by watching "Dallas."

The Defense Department is also concerned that Soviet-bloc scientists may use the supercomputers to solve weapons design and code-breaking problems, thus saving the Soviets research and development costs. There is no evidence, however, that the universities are incapable of guarding against misuse of machine time on the supercomputers.

Certain foreign scientists will benefit from the enormous power of these machines, but American scientists will also benefit from collaboration with their foreign counterparts. There is no evidence that open scientific communication of unclassified ideas results in damage to the national security. Indeed, the openness of our scientific system is in large measure the source of our technological advances.

Moreover, the administration's plan is impracticable. It is unrealistic to expect the universities to check, on their campuses and elsewhere, the citizenship of scientists and their staffs who request time on the supercomputers. It is also an open question whether our allies, who have received the supercomputers from us, or Japan will follow our restrictive policy.

Most troubling about the administration's plan are the ramifications for academic freedom. An essential precondition of academic freedom is unhampered control by a university in determining who may use its research facilities. Once that autonomy is surrendered to an external body, the university becomes to that extent an adjunct of that body.

The administration wishes to predetermine on grounds of nationality which foreign scientists may pursue research projects at universities using machines that are intended for nonclassified work. Such a policy is erosive of a vital protection of academic freedom and in the long run will hamper open scientific inquiry to the detriment of keeping ahead of our adversaries.

The benefits of the administration's plan seem scant, the costs to freedom too high merely for the possibility of delaying the technological progress of other nations. Before the administration goes any further with this plan, a full public debate is in order on whether quarantining the supercomputers truly serves the national interest.