To prevent the spread of nuclear weapons, the Reagan administration is expected to announce its willingness to provide conventional weapons and the protection of the American nuclear umbrella to selected nations, according to State Department officials.

The eight points in the new policy are very broadly worded -- so much so that one administration official called the document "pap" -- but they appear to take a stand stronger than President Reagan's previous comments against the spread of nuclear weapons.

The new policy was prepared by the State Department as one of several policy reviews, including the Strategic Arms Limitation Talks and the transfer of conventional weapons. The White House now must pass on it and is expected to make its announcement of the policy next week, just before the July 19-21 meeting in Canada of the leaders of seven industrial nations.

The new policy stresses one point that the Reagan administration has pressed all along -- to make the United States a "reliable and credible" supplier of nuclear equipment and technology by not placing heavy restrictions on sales to most nations. Rather, the policy will attempt to identify nations that might use peaceful technology to make bombs and limit transfers to them, a State Department official said.

Nations seeking nuclear weapons might be dissuaded if the United States could cover their security needs by providing conventional weapons and a nuclear-deterrent umbrella.

There were misgivings about the administration plan on Capitol Hill. "I don't think you can look at these eight points and come to any conclusion about what the Reagan administration is doing. They are too general," said Leonard Weiss, minority staff director of the Senate subcommittee on energy and nuclear proliferation. s"I'm very concerned about the direction they are going in, however."

He said they seem headed toward loose policy which helped create situations like those in Iraq and Pakistan and other countries.

The nuclear industry believes the policy is a "step forward" from uncertainty in the Carter administration, said Dixon Hoyle, a non-proliferation specialist with Westinghouse. He especially cited the administration's willingness to separate countries such as Pakistan, Iraq and Libya from those like Japan and Germany that are unlikely to develop a bomb but genuinely need nuclear power.

In a press conference in Florida during his election campaign, Reagan said that the United States should not stand in the way of countries wanting to develop nuclear weapons. "I just don't think it's any of our business," he said. Elsewhere in the same session he did affirm his support of non-proliferation efforts, but said that as a practical matter it would be difficult.

The eight points in the new policy, according to a State Department official:

Reaffirm that preventing the spread of nuclear weapons is a principal goal of the Reagan administration.

Recognize that the security of a nation is often a factor in considering whether to get nuclear weapons, and be prepared to use coventional arms sales and possible extension of the U.S. nuclear umbrella.

Reaffirm support for the 1970 Non-Proliferation Treaty, as well as the pact establishing Latin America as a nuclear-free zone.

Reaffirm support for the International Atomic Energy Agency and its safeguards against possible use of nuclear fuel and technology to make weapons.

Establish better cooperation among nuclear-supplier countries to prevent the transfer of sensitive technology and material where a risk of weapons production is involved.

Strengthen intelligence for detection of weapons-related activity, including upgrading satellite detection systems.

Pledge the United States to remain a reliable and credible nuclear supplier to nations observing international nuclear safeguards.

Form a policy on the transfer of spent U.S.-supplied fuels to third countries for reprocessing where no weapons threat is involved.