21st Century Science for Nuclear Waste Disposal Act of 2004 - Amends the Nuclear Waste Policy Act of 1982 to repeal the authority of the Secretary of Energy (Secretary) to enter into contracts for the acceptance of title, transportation, and disposal of spent nuclear fuel or high-level radioactive waste.
Declares that the Nuclear Waste Fund shall be available to the Secretary only to pay the cost of research, development, and utilization in the United States of risk-decreasing technologies, with an emphasis on technologies that: (1) increase the length of time that nuclear waste can be safely stored at or near areas where currently located or where (in the future) generated; (2) require the least amount of transportation of nuclear waste practicable; and (3) reduce the level of radiation of the nuclear waste.
Prohibits the government from using funds for research, development, or implementation of a central high-level radioactive waste and spent nuclear fuel repository.
Repeals the Nuclear Waste Policy Act of 1982, but retains requirements governing: (1) financial arrangements for site closure for low-level radioactive waste; (2) the Nuclear Waste Fund; and (3) Nuclear Regulatory Commission training authorization.
Amends the Internal Revenue Code to repeal special rules governing nuclear decommissioning costs.