President Reagan gave his permission Wednesday for Canada to buy tightly held U.S. nuclear submarine technology, but he and Canadian Prime Minister Brian Mulroney appeared to make little headway in settling a dispute over acid rain.

The leaders met at the White House for an hour to discuss their differences over the acid rain pollution problem, but "nobody tried to bridge" the disagreements, a senior U.S. official said.The official said that during a half-hour private session Mulroney presented some new ideas on the issue, but further discussions between experts will be required before it can be determined if the proposals are palatable to the United States.

The Canadian government is considering the purchase of 10 or 12 nuclear-powered attack submarines, either from Britain or France. Since the British "Trafalgar" class subs use American power plants, U.S. permission will be required if the Canadians pick the British design.

The official said Reagan informed Mulroney that he would approve the technology transfer making Canada the first nation outside Britain to be eligible to acquire the technology.

Congressional approval also is necessary.

Mulroney, with Reagan standing beside him at a welcoming ceremony on the South Lawn of the White House, reminded the president that they had pledged during a meeting in Canada to work together on the acid rain problem.

"This, as you said in Quebec City, Mr. President, is a problem that belongs to both of us. We must continue and we shall to work together for an equitable solution to this important challenge," Mulroney said.

Reagan said the agreement would lead to an "unshackling" of U.S.-Canadian trading relations.