Diplomatic fallout from the breakup of the Soviet nuclear-powered space satellite over Canada may parallel the radioactive fallout, U.S. specialists said yesterday.

Even before the Canadian report that "extremely dangerous" nuclear debris appears to have landed on its territory, senior administration officials said "there is bound to be agitation" from any nations for tighter safety standards.

There are also signs of tougher international demands to bar nuclear-power devices from space. Some nations also are protesting that they were not forwarned of the Soviet satellite malfunction. Sweden expressed "regret" to the Soviet embassy in Stockholm about the lack of warning its Foreign Ministry confirmed.

There was a morning-after reaction by the Carter administration yesterday to the episode in which it commended "the very cooperative fashion" in which the Soviet Union replied to questions from the United States about the satellite before it broke up. The State Department said: "We are considering several possible initiatives as a result of this incident."

This includes the possibility of expanding agreements with the Soviet Union, such as the 1967 Outer Space Treaty, said press officer Jill A. Schuker.

The treaty makes nations liable for damages from space objects which they launch, and can be invoked by Canada against the Soviet Union. Considerable ferment is now expected inside the United Nations Outer Space Committee on the adequacy of this treaty.

In Japan yesterday, a leading anti-nuclear-bomb organization sent a protest to Soviet President Leonid I. Brezhnev demanding the immediate withdrawal of all its nuclear-powered satellites from space.

A prominent West German newspaper, the Frankfurter Allgemeine, in contrast to the Carter administration's commendation to the Soviet Union for cooperation, charged that the Soviet Union "acted irresponsibly" in failing to issue its own warning that it had "lost control of the satellite."

Carter administration officials, however, generally have taken the opposite tack, recognizing the sensitivity they shared with the Soviet Union about what are highly secretive "spy" satellites.

Neither the United States nor the Soviet Union discusses these military reconnaissance satellites in public. And yet they are the foundation for all nuclear strategic arms limitation negotiations, to detect nuclear weaponry.

As a result, many American specialists were skeptical that the Soviet Union would provide any information about its out-of-control space satellite, when national security affairs adviser Zbigniew Brzezinski, on Jan. 12, first raised the issue with Soviet Ambassador Anatolly F. Dobrynin.

"Frankly, I thought they were likely to tell us to go to hell," said one administration specialist.

From a Soviet standpoint, there was a danger that the United States was embarked on a damaging propaganda campaign, to tell the world that a Soviet spacecraft containing nuclear threat had run amok. Instead, it said, Brzezinski was able to convince Dobrynin that the United States genuinely "was seeking information" to minimize a global hazard and was "not sandbagging them for PR ( (KEY OFF) ublic (KEYWORD) relations purposes."

After Brzezinski's initial inquiry to Dobrynin on Jan. 12, the Soviet Union replied with unusual swiftness, but without adequate detail, on Jan. 13, and a further inquiry on Jan. 17 brought "more complete answers" on Jan. 19. "They didn't give us a tremendous amount of information," an informed source said, but we didn't ask for a lot."

Some critics contend that the manner in which the United States alerted some nations, but not others, and then publicized the fall of the Soviet satellite was an unwarranted "grandstand play" by Brzezinski and the White House.

Other U.S. officials strongly disagree, saying it would have been "stupid and shortsighted" not to alert close allies, for if the satellite debris had hit their territory "we would have been guilty" of concealing information. And yet to alert all nations, these officials argue, would have risked "mass hysteria," so the choice was difficult.