Critical and Source Driven Subcritical Systems for: - Waste Transmutation - Fuel Breeding

1. Critical and Source Driven Subcritical Systems for: - Waste Transmutation - Fuel Breeding Phillip Finck Associate Laboratory Director for Nuclear Science and Technology September 30, 2009

2. Moving Forward with the Nuclear Renaissance • Current goals are to significantly reduce greenhouse gas emissions and increase energy security • Nuclear energy can be a major contributor with a five-pronged approach Imperative 1 – Extend life, improve performance, and sustain health and safety of the current fleet. Imperative 2 – Enable new plant builds and improve the affordability of nuclear energy Imperative 3 – Enable the transition away from fossil fuels in the transportation and industrial sectors Imperative 4 – Enable sustainable fuel cycles Imperative 5 – Assure that proliferation risk is not an obstacle to nuclear power deployment

3. Historical Background on Waste Transmutation and Breeding • Early in the nuclear age, Fermi and others became concerned with fissile (U5) supplies and launched fast breeder programs • Large RD&D programs until the 1980’s (post TMI), when supply issues disappeared • Most individual technologies had been demonstrated • Existing facilities were then converted to MOX recycle in LWRs • In the late 1980’s, Japan started investigating Waste Transmutation using Dual Tier Approaches with ADS Transmutation of Minor Actinides • These activities peaked around 2000 and now most large national programs are focused on reactor based waste transmutation • Fissile resources are not an issue today • Probably will not be an issue until late in the century unless a massive nuclear renaissance occurs

4. In the late 1980’s, Japan started investigating Waste Transmutation using Dual Tier Approaches with ADS Transmutation of Minor Actinides • These activities peaked around 2000 and now most large national programs are focused on reactor based waste transmutation • Fissile resources are not an issue today • Probably will not be an issue until late in the century unless a massive nuclear renaissance occurs

5. Used Fuel Pu, U, & MA Removed ~300 Years ~10,000 Years ~300,000 Years Natural Uranium Ore U & Pu Removed Time (years) LWR Fuel 50 GWd/MT, 5 Years Cooling Waste Issues • Issues: • Repository Utilization and Dose • Radiotoxicity • Materials Proliferation

6. Fast Reactor Fast Reactor Separate Separate Fuel Fuel LWR Fuel Disposal Disposal Single and Dual Tier Approaches for Waste Transmutation • Dual Tier (FR, ADS, or FFH) – • U and Pu from LWR used fuel is fabricated into “conventional” MOX fuel and undergoes one or two passes through an LWR prior to multiple recycles in fast spectrum reactors • Uses existing technologies to burn some of the Pu • Total destruction of Pu is possible in theory, but very complex (practical limit is ~ 50%) • Need fewer fast systems (5% - 15%) with small advantage to subcritical systems (CR=0) compared to critical systems (CR > 0.25) • Single Tier – • All TRU elements from LWR used fuel are separated together, and continuously recycled in fast spectrum reactors (US approach) • Requires ~ 30% fast systems in equilibrium • Fast system capital cost dominates cost penalty compared to once through

7. Fast Reactor Fast Reactor Separate Separate Fuel Fuel LWR Fuel Disposal Disposal

8. LWR Used Nuclear Fuel Used Nuclear Fuel Separations Challenges for Closed Fuel Cycles Yucca Mountain repository characteristics were the main driver for system architecture and specific technologies Yucca Mountain Repository Interactions Repository Interactions Integrated Waste Strategy Process Scale-up Safeguards Process Scale-up Process Losses Transuranic Fuel Performance Economics

9. Comparative Challenges for Subcritical Systems • Fuel Cycle Challenges • Cost of transmuter • Advanced fuels • Advanced separations • Fuel cycle integration • Interface Challenges • Coupled operations • Safety • Wall technology • Cost increase • Source Challenges • ? Can the source driven approach reduce or eliminate any of the fuel cycle challenges?