The nuclear energy industry supports research, development and demonstration of improved or advanced technologies to close the nuclear fuel cycle, thereby potentially reducing the volume, heat and toxicity of byproducts placed in the repository, recognizing that a geologic repository will be required for all fuel cycles.
• The growing need for low-carbon electricity generation has led to a continued interest in nuclear power and a reassessment of the nation’s long-term used fuel management program, including renewed interest in advanced reprocessing and recycling of used nuclear fuel, advanced fuel fabrication, and development of new reactor designs that could further minimize byproducts of the nuclear fuel cycle.
• The federal government and industry should pursue research into advanced recycling and reactor technologies as well as development of existing technologies. However, no advanced technology will preclude the need for a federal geologic repository for the ultimate byproducts of recycling used nuclear fuel.
• The expected growth of nuclear energy around the world is a key driver behind development of advanced fuel-cycle technologies. Any decision to pursue advanced fuel cycles must consider the economic and nonproliferation factors associated with recycling used nuclear fuel, and the United States should endeavor to lead the development of such technologies.
• Recognizing that licensing and constructing a new recycling facility, using available technology, is approximately a 20-year endeavor, the federal government must have a stable public policy supporting recycling that enables companies to make the long-term capital-intensive investments necessary to pursue recycling.
• The Department of Energy (DOE), in conjunction with industry, must develop a coherent technology research and development plan, with defensible milestones, that supports the commercialization and deployment of advanced fuel-cycle technologies.
Nuclear reprocessing is the extraction of various elements—currently plutonium and uranium—from used fuel assemblies. During reprocessing, the used fuel assembly is separated into useable and non-useable material. The non-useable material may be in multiple forms (e.g., high-level and low-level waste) and will have to be properly disposed of. In addition, industrial waste is created.
Nuclear recycling is the extraction of useable material from used fuel assemblies and the subsequent reuse of that material in reactors. Recycling describes an integrated life-cycle process that results in the production of new reactor fuel from used nuclear fuel. Reprocessing is a stage in this lifecycle.
Evaluating Used Nuclear Fuel Recycling in the United States
The United States, primarily for economic reasons, does not currently reprocess or recycle used nuclear fuel. Commercial reactor fuel remains in the reactor for three or four years. Under the current U.S. approach, that fuel then is to be removed for ultimate disposal in a specially designed repository, despite the fact that significant energy remains in the fuel.
Recognizing the nonproliferation ramifications of recycling used nuclear fuel, multiple administrations have either endorsed or discouraged recycling in the United States. Although administration positions have changed, no federal law exists that bans reprocessing or recycling from occurring in the United States.
Recycling of used fuel has the potential to reduce the need for new uranium supply and enrichment services and to enhance the energy and national security of the United States. It also has the potential to provide greater utilization of a geological repository for high-level radioactive waste by reducing the volume, heat and toxicity of byproducts in the repository.
In the United States, reprocessing and recycling should entail the following:
• establishing the policy and regulatory requirements for recycling facilities
• developing advanced used fuel recycling techniques
• deploying new fuel designs in existing reactors
• developing advanced reactors, including fast reactor technologies, to extract additional energy from recycled fuel and further reduce the volume, heat and radiotoxicity of byproducts
• disposal of byproducts in a federal repository.
Advanced fuel-cycle technologies cannot eliminate all of the byproducts in used nuclear fuel. Moreover, the systems eventually developed may not have the capacity to recycle all the commercial used fuel generated. The United States still will need a federal repository for disposal of these byproducts and for any used nuclear fuel that is not reprocessed.
Repository disposal also is needed for the high-level radioactive waste created by the federal government from its defense programs. Most of this material is stored temporarily in Idaho, South Carolina and Washington.
Looking to the Future
France, the United Kingdom, Japan, and Russia operate reprocessing facilities. In France, the United Kingdom and Japan, plutonium (Pu) and uranium (U) from used fuel are or will be recycled into UO2 and MOX (mixed oxides of Pu and U) fuel assemblies. Following use in a light water reactor, the used MOX fuel assemblies are stored with the intention of utilizing the useable material when fast reactors are available. France does not currently operate commercial fast reactors. The deployment of commercial fast reactors could enable France to significantly increase its recycling capability and extract more energy from the recycled material. France is currently developing prototype fast reactors.
Liquid metal cooled and fast reactor technologies also could support government-sponsored nonproliferation efforts by consuming stockpiles of plutonium and material from former nuclear weapons, thus eliminating them as a threat.
Today’s reprocessing technology—known as PUREX—makes it possible to recycle and reuse the uranium and plutonium from used nuclear fuel. The remaining waste products are mainly unusable fission products, which are mixed with glass for disposal as high-level radioactive waste in a process known as vitrification.
The uranium and plutonium separated from used reactor fuel by PUREX reprocessing can be recycled as mixed oxide fuel. The PUREX process produces plutonium that is stored under strict security and safeguards as provided in internationally agreed protocols.
Advanced reprocessing systems would not separate plutonium. Instead, they would keep uranium, plutonium and other usable elements together, while separating radioactive byproducts that have no energy value. One such process, called UREX+, extracts the fission products from used fuel, leaving the remaining plutonium mixed with uranium and other elements. These uranium isotopes are extracted with the plutonium and recycled as fuel for advanced reactors. Although proven in laboratories, UREX+ is not yet commercially proven. The French are developing a process called COEX, which extracts uranium and plutonium together. In the United States other processes, such as “pyroprocessing,” that use metallurgical technology also are being developed.