The transfer of U.S. nuclear energy technology to China could pose risks for the United States by the end of the century, but they are outweighed in the short term by the political and economic benefits of cooperation, according to a congressional report released yesterday.

The report by the Office of Technology Assessment says the risks and benefits should be considered as Congress reviews a recently signed nuclear cooperation agreement with China that outlines conditions under which U.S. industry may bid on China's nuclear power-plant construction. At least $6 billion in foreign business is expected to be involved.

A special trade subcommittee of the House Committee on Energy and Commerce has a hearing scheduled on the matter today, and officials from agencies and departments including State, Energy and the Arms Control and Disarmament Agency, are expected to testify.

Critics of the Reagan administration agreement are concerned about its vagueness regarding safeguards for exports and the possible reprocessing of spent nuclear fuel, a procedure that can yield material usable in weapons. The proposed agreement only specifies future "consultations" to arrange "exchanges of information and visits to material, facilities and components."

The Nuclear Control Institute, a coalition concerned about energy policy, said the agreement threatens to erode U.S. nonproliferation policy, congressional prerogatives in overseeing that policy and invites diplomatic disputes with China. The administration has said the pact meets all provisions of U.S. law and the Nuclear Nonproliferation Treaty.

It has been widely reported that China has helped Pakistan design and construct a centrifuge enrichment plant and perhaps nuclear weapons, but the congressional report said it could not verify the charge.

Among the other concerns mentioned in the report is the risk accompanying technology transfer that could result in the upgrading of China's nuclear submarine program. Exposure to modern industrial practices, the report said, could allow China to produce submarines that are quieter, more reliable and more powerful.

But, the report said, congressional rejection of the agreement would have little effect on China's ability to export nuclear technology or to use it to upgrade its submarines. China already has the reprocessing and enrichment technology that could create proliferation dangers if exported without safeguards and is importing other foreign expertise that could be useful in improving its nuclear submarines, according to the report.

Congressional rejection of the agreement would also mean the United States might lose most or all of Washington's influence on Peking's nonproliferation policy and nuclear development, the report said.