The Future of Nuclear Waste Management, Storage, and Disposal Thanassi Lefas 26 November 2008 ChE 359 Energy Technology and Policy Hi, my name is Thanassi Lefas. I’m a senior in Chemical Engineering at the University of Texas and today I’m going to talk to you about the future of nuclear waste management, storage, and disposal

Road Map Identify importance of nuclear waste management Define nuclear waste Identify health risks Discuss initial treatments of waste options Vitrification Ion Exchange Discuss permanent disposal of waste options Geological Repositories Deep Boreholes Separation and Transmutation Space Disposal Conclusions/Recommendations

Importance of Nuclear Waste Management Nuclear power carbon free energy source Currently limited by economics, safety, and technology Clear limiting factor, lack of permanent disposal Growth of nuclear capacity will require development of permanent disposal options Critical considerations Safety Security

Nuclear Waste Composed of radionuclides Low, Medium, and High-level waste High-level waste produced in nuclear reactors Consists of Fission products (short-half lives) Actinides (long-half lives) Of note: 99Tc, 129I, 239Pu, 240Pu, 235U, 238U

Health Risks Somatic Effects Genetic Effects Teratogenic Effects Cancer Genetic Effects Hereditary Genetic Damage Teratogenic Effects Birth defects Prenatal death

Vitrification/Ion Exchange Purpose Prevent reaction or degradation of waste for extended period of time Vitrification Combine waste with molten glass, harden to form new solid Ion Exchange Combine with chemical to concentrate waste and encase in cement

Geological Repositories Isolate High-level nuclear waste Waste Package Engineered Seals Natural Bedrock Sites w/ appropriate Hydrological and Geochemical environments Low solubility and mobility of radionuclides In United States, Yucca Mountain north of Las Vegas

Deep Boreholes Similar concept to basic geological repositories Kilometers deep rather than hundreds of meters Provide Further isolation from ground water More potential borehole locations around the globe Can be created in many cases close to power plants Not subject to tectonic, volcanic, and seismic interference

Separation & Transmutation Long-lived isotopes extracted from nuclear waste and destroyed Removal of long-lived isotopes opens up more repository options reduces thermal load on repositories, thereby increasing their capacity destroys plutonium, ensuring that it can’t be recovered and used for nuclear weapons

Space Disposal Removes the waste from the biosphere entirely High risk of space vehicle failure High energy cost of space launch Relatively limited volume per launch High cost

Conclusions/Recommendations Optimization of ion exchange Results in compact form of waste that will not interact with biosphere Research and Pursuit of Deep Boreholes Further development of deep boreholes that are more reliable are an ideal option Reasonable Cost Global availability Human Safety

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