President Tito indirectly but unmistakably expressed public concern today to Vice Presiden Mondale over the Carter administration's campaign on human rights and testly defended Yugoslavia's record in that field.

Tito's assertion to reporters that "no reproach can be addressed to Yugoslavia in this connection" puzzled American officials, who said that Mondale had not questioned Yugoslavia's human rights record in his private talks earlier in the day with Tito.

Belgrade was the next-to-the-last stop in a five-nation, 10-day trip Mondale is making in Western Europe. He flies to London Sunday and returns to Washington Monday to report to President Carter on his talks this week with South African Prime Minister John Vorster in Vien.

Mondale was able to defuse a potential confrontation over the Carter administration's tougher policies on nuclear exports by announcing that Washington decided yesterday to license the export of key components for an electricity-generating nuclear power plant that Yugoslavia is building.

Disagreement over American demands for new controls over what happens to fuel that passes through the reactor had stalled the license, bringing complaints from Belgrade that delays in the April 1 delivery date were costing it $20 million a month.

For the second time this week, the Carter administration softened its stand by agreeing to license export of a reactor before agreement on the fuel cycle had been reached. Mondale announced in Spain that a reactor delayed on those grounds had been approved for Madrid.

At issue in both cases was Washington's attempt to establish some control over the reprocessing or storage of uranium supplied by other countries but used in American reactors.

While emphsizing that it had no objections to stronger international controls, Yugostavia reportedly argued that it was being discriminated against by being the first country to be asked to accept the new controls as a condition of purchase.

Negotiations will be resumed shortly for deliveries of American fuel when the reactor is complete in 1979.

Tito and Mondale met with reporters for a joint statement after their talks.Immediately after saying that Belgrade would play host next month to a conference to review the 1975 Helsinki accords, Tito desclosed that he had expressed to Mondale "concern about a campaign that has been led in some countries about democracy and human rights."

American officials speculated later that Tito may be worried that the Belgrade conference could degenerate into a name-calling session if tha human-rights issue is pushed too hard. He also appeared to be trying to establish clearly that Yugoslavia's more open society should not be compared to its East European neighbors.

Mondale appeared fully recovered today from the attack of gastroenteritis that had forced him to cancel his first round of meetings with Yugoslav officials yesterday.