President Carter overturned a Nuclear Regulatory Commission decision yesterday and authorized the export of 17,000 pounds of uranium to India.

The NRC refused by a 2-to-2 vote April 20 to grant the export license, partly because India has declined to adopt full international safeguards against the use of spent nuclear fuel to make atomic bombs.

Carter, who has made a halt in the spread of nuclear weapons one of his leading foreign policy goals, outlined his decision yesterday in an executive order transmitted to Congress. Under law, the sale still could be blocked if the Senate and House pass resolutions of dispproval within the next 60 days.

A White House official said the administration is hopeful Congress will not block the sale. But considerable liberal oppostion is likely to develop against supplying additional uranium to India, which detonated an atomic bomb in 1974.

Carter strongly supported enactment last month of the Nuclear Proliferation Act, which beginning in March 1980, will prohibit nuclear exports to countries that do not agree to international safeguards for their nuclear facilities.

At the same time, however, the president promised Prime Minister Morarji Desai in January when Carter visited India that he would authorize this export sale, part of a longstanding contract between the United States and India.

In a message to Congress, Carter said he is confident that India will keep a promise to use the uranium only at its Tarapur nuclear power station and will not use it to make explosive devices.

Moreover, the president argued, rejection of the export license would "seriously undermine" U.S. efforts to get India to agree to safeguards before the March 1980 deadline on future exports.

"Rather than prejudice the prospect for success in such efforts by refusing to fulfil an existing committment that is important to India's power supply, we should be using this period to find, in light of the new legislation's requirements, matually acceptable ways of meeting both India's need for continued operation of the Tarapur atomic power station and our need for full-scope safeguards and the attainment of other non-proliferation objectives," he said.

During Carter's visit to India, the nonproliferation issue dominated his talks with Desai. There was little progress evident then. A White House official said yesterday that unless significant progress is made in moving India toward accepting safeguards, the shipment authorized yesterday would be the last from the United States to India.

The 200,000-kilowatt nuclear plant at Tarapur will have to be reloaded sometime in the next year or its electrical output will be gradually reduced. The 17,000-pound to six-month supply of finished nuclear fuel, officials said.

In another development yesterday, Carter enlarged the responsibilities of the White House office of consumer affairs by ordering his consumer affairs adviser, Esther Peterson, to assess for him the potential impact on consumers of administration programs and policies while they are being formulated.

The president also asked Peterson to review existing government consumer programs and to recommend improvements.

The presidential order came in the wake of Congress' refusal to approve administration-backed legislation to set up an independent advocate of consumer viewpoints before federal agencies.

Peterson said granting the consumer office a role in formulating administration policy was the most important aspect of the order. However, she ducked questions on her position on a number of controversaial issues, among them Carter's attempt to impose a tax on domestic oil production in order to drive up fuel prices and reduce consumption.