A panel of the National Academy of Sciences urged President Bush on Monday to abandon an ambitious plan to resume nuclear waste reprocessing that is the heart of the administration's push to expand the civilian use of nuclear power.

A 17-member panel of the Academy's National Research Council said the proposed Global Nuclear Energy Partnership, or GNEP, has not been adequately peer reviewed and is banking on reprocessing technology that hasn't been proven, or isn't expected to be ready in the time the administration envisions.

The report, released Monday, said GNEP research is taking money and focus away from other nuclear research programs and efforts to speed the construction of new nuclear power plants.

"All committee members agree that the GNEP program should not go forward and that it should be replaced by a less aggressive research program," said the panel. It said if the administration proceeds as planned there will be "significant technical and financial risks."