A federal judge was urged today to name a panel of independent scientists to test the government's claim that a proposed article for Progressive magazine on the design and manufacture of hydrogen bombs would cause "grave, direct, immediate and irreparable harm to the national security of the United States and its people."

The perils of publishing the article must be subjected to "an exacting standard of proof" to overcome the "heavy presumption" of the Supreme Court that prior restraint on the press is always unconstitutional, the American Civil Liberties Union said in a friend-of-the-court bried.

Lawyers for the ACLU, a 200,000-member organization, filed the brief with U.S. District Court Judge Robert W. Warren. He has set March 26 for a hearing on the government's application for a preliminary injunction to prevent the Progressive from publishing the article. The monthly's deadline for its May issue is also March 26.

The ACLU emphasized that government employes and experts have, in the words of a federal appeals court, a "natural inclination" to assert national security justifications for secrecy even though, the bried argued, disclosure in fact "would not jeopardize the national security."

Drawing from "what could be a very long catalog," the ACLU also listed examples of government "overreaction and overprotectiveness" toward national security data.

One example was the Pentagon Papers, the Defense Department's classified history of American involvement in Vietnam. In that case, the government claimed that publication of the papers would pose a "grave and immediate danger to the security of the United States."

But the Supreme Court ruled 6 to 3 that the government hadn't overcome the heavy presumption against prior restraints and allowed the New York Times and The Washington Post to publish the papers.

In the eight years since that ruling, "no one has asserted -- let alone demonstrated -- that publication" of the Pentagon Papers has had grave consequences for the United States, the ACLU said.

The ACLU also stressed that the Supreme Court, recognizing the prevention of prior restraints as the central purpose of the guarantee of freedom of the press in the First Amendment, never has departed from the rule against such restraints that it formulated 70 yars ago.

"At first blush," the ACLU said, the technical information in the proposed article may fit the court's narrow description of an occasion when the press would have to yield its right to decide what to publish.

But the public affidavits and other materials filed in support of the temporary restraining order that Judge Warren granted last Friday don't "allege, let alone prove," the type of injury or the cause-effect connection needed to uphold a prior restraint on the press, the ACLU contended. Instead of "concrete proof," the documents offer "conclusory predictions" and speculation, the brief argued.

The ACLU acknowledged, however, that it has had no chance to review more recent affidavits in which numerous government experts on thermonuclear warfare contend that the article, by free-lance writer Howard Morland, contains data that, if published, would disclose H-bomb secrets.

One government expert, Jack W. Rosengren, said the article "goes far beyond any other publication in identifying the nature of the particular design used in the thermonuclear weapons in the U.S. stockpile." He also said that the article contains information "properly classified as secret" that has "never been released anywhere before."

But the monthly's editor, Erwin Knoll, saying that Morland had "no access to any classified documents," has accused the government of seeking to protect not the national securith, "but its own ineptitude in classifying as secret information that is already available to any serious jouralist." The ACLU said it understands "that the government objects at most to 20 percent of the article."

In urging Judge Warren to appoint the panel of independent experts, the ACLU said it could aid him "in determining the technical factual issues which are central to this case" and could advise him whether the dangers of publication "are as great as the government asserts." The organization offered to provide a list of potential candidates.

In seeking the preliminary injunction, the government is invoking the Atomic Energy Act's definition of "restricted" information: "all" data concerning the design, manufacture or utilization of atomic weapons.

This definition, the ACLU said, "is grossly overbroad on its face," because it includes "encylopedia articles on nuclear weaponry, newspaper articles on Einstein's life and work" and even "debate over limitation on nuclear weapons."