Advanced LWR Fuels Research in the United States Shannon Bragg-Sitton Idaho National Laboratory

Transcription

1 Advanced LWR Fuels Research in the United States Shannon Bragg-Sitton Idaho National Laboratory IAEA TWG on Fuel Performance & Technology April 24-26, 2013

2 Outline Introduction Education Professional experience Overview of LWR fuels research Brief overview of US nuclear power plants US Department of Energy Office of Nuclear Energy programs related to LWR fuel development: Light Water Reactor Sustainability Program, Advanced LWR Fuels Pathway Fuel Cycle Research and Development, Advanced Fuels Campaign Advanced LWR Accident Tolerant Fuel (ATF) development 2

3 Personal Background Education B.S. Nuclear Engineering, Texas A&M University (1997) M.S. Medical Physics, University of Texas at Houston, Graduate School of Biomedical Sciences (1999) M.S. Nuclear Engineering, University of Michigan (2001) Ph.D. Nuclear Engineering, University of Michigan (2004) Dissertation: Analysis of Space Reactor System Components: Investigation Through Simulation and Non-Nuclear Testing 3

4 Personal Background Experience Los Alamos National Laboratory ( ) Space reactor design, analysis and non-nuclear testing NASA Marshall Space Flight Center ( ) Interagency assignment from LANL to NASA Non-nuclear testing of space power and propulsion systems Fast spectrum reactor autonomous control system design Texas A&M University ( ) Assistant Professor, Nuclear Engineering Courses taught: Intro to Nuclear Engineering; Space Nuclear Systems; Plasma Physics; Reactor Experiments Laboratory Idaho National Laboratory (2010-present) Manager, Space Nuclear Systems &Technology ( ) includes development of W-UO 2 cermet fuel for a nuclear thermal propulsion engine Nuclear Hybrid Energy Systems concept development DOE LWR Sustainability, Advanced LWR Fuels Pathway Lead (2012-present) DOE Fuel Cycle Research & Development, Advanced Fuels Campaign, Advanced LWR Fuels Technical Lead (~Fall 2012-present) DOE Used Fuel Disposition Campaign, Deputy National Technical Director (April 2013) 4

5 Areas of Experience Small nuclear reactor systems Applications: Terrestrial power, space power or space propulsion Fast spectrum reactor design Various cooling systems considered: liquid metal, heat pipe, direct gas cooled Non-nuclear (electrically heated) system testing Control system design and testing with simulated reactivity feedback Cermet fuel development (W-UO 2 ) for nuclear thermal rocket engines Light water reactor fuel development Fuel development activities associated with accident tolerant fuel Development of a test and qualification program for advanced fuel and cladding materials Advanced cladding development activities: initial focus on SiC-based designs 5

6 G i g a w a t t s - e l e c t r i c U.S. Commercial Reactor Fleet 104 Operating Reactors 69 PWRs 35 BWRs 5 units currently under construction (four AP1000 units and one Gen II PWR) Pressurized Water Reactors Westinghouse Combustion Engineering Babcock & Wilcox Average 3.0 GWth (max 3.99 GWth, min 1.5 GWth) Cladding: Zirc-4, ZIRLO, M5 Batch average enrichment: % Avg. discharge BU: GWd/MtU (avg. 48.6) Increasing trend Cycle length: EFPD (avg. 512 EFPD) Current reactors, 40 years Current reactors, 60 years New capacity being considered 4 Builds per year starting 2021 Generating capacity with 80-year life

7 U.S. Commercial Reactor Fleet Boiling Water Reactors All General Electric Average 3.0 GWth (max 3.95 GWth, min 1.8 GWth) Cladding: Zirc-2 Batch average enrichment: % Average discharge BU: GWd/MtU (avg. 44.8) Increasing trend Cycle length: EFPD (avg. 612 EFPD) Units under construction Southern Company, Vogtle 3, 4 (Georgia) AP1000 South Carolina Gas & Electric, Summer 2, 3 (South Carolina) AP1000 Tennessee Valley Authority, Watts Bar 2 (Tennessee) Gen II PWR (construction suspended in 1985, construction now resumed) 7

8 Nuclear Energy Share in U.S. Electricity Production 8

9 LWR Sustainability Program Goals Developing the fundamental scientific basis to understand, predict, and measure changes in materials and systems, structures, and components (SSCs) as they age in environments associated with continued longterm operations of the existing reactors Applying this fundamental knowledge to develop and demonstrate methods and technologies that support safe and economical long-term operation of existing reactors Researching new technologies to address enhanced plant performance, economics, and safety LWRS Program provides technical foundations for licensing and managing the long-term safe and economical operation of current nuclear power plants (NPPs), utilizing the unique capabilities of the national laboratory system 9

10 LWRS Pathways Materials Aging and Degradation Develop scientific basis for understanding and predicting long-term environmental degradation behavior of materials in nuclear power plants Provide data and methods to assess performance of systems, structures, and components essential to safe and sustained nuclear power plant operation, providing key input to both regulators and industry Instrumentation, Information, and Control System Technologies Develop, demonstrate, and deploy new digital technologies for instrumentation and control architectures and provide monitoring capabilities to ensure the continued safe, reliable, and economic operation of the nation s operating nuclear power plants Risk Informed Safety Margin Characterization Develop and demonstrate a risk-assessment method that is tied to quantification of safety margins Develop advanced safety assessment tools that can enable a more accurate representation of a particular plant safety margin Advanced Light Water Reactor Nuclear Fuels (collaborative w/fcrd) Improve scientific knowledge basis for understanding and predicting fundamental nuclear fuel and cladding performance in nuclear power plants Demonstrate advanced nuclear fuel that will improve the safety margin, reliability and economics at existing nuclear power plants 10

11 DOE FCRD Advanced Fuels Campaign has 3 Focus Areas 11

12 US DOE Advanced Fuels Research U.S. DOE Office of Nuclear Energy (DOE-NE), in collaboration with the nuclear industry, has been conducting R&D activities on advanced LWR fuels for the last few years Emphasis for these activities was initially on improving the fuel performance: Increased burnup for waste minimization Increased power density for power upgrades Collaborating with industry on fuel reliability Events at Fukushima in March 2011 resulted in redirection of program efforts 12

13 US DOE Advanced Fuels Research, cont. Consolidated Appropriations Act, 2012, Conference Report , the U.S. Congress directed DOE-NE to: Give priority to developing enhanced fuels and cladding for light water reactors to improve safety in the event of accidents in the reactor or spent fuel pools. VISION: To have an LWR fleet with enhanced accident tolerance providing a substantial fraction of the national clean energy needs. Evaluate concepts with respect to accident scenarios and specific plan designs for LWRs New advanced fuels must be evaluated within the context of the other potential improvements to enhance overall safety (e.g., access to emergency cooling water, additional battery power, etc.) MISSION: Develop advanced fuels/cladding and non-design intrusive reactor system technologies (e.g. instruments, auxiliary power sources) with improved performance, reliability and safety characteristics during normal operations and accident conditions, while minimizing waste generation. Initial effort focuses on applications in operating reactors or reactors with design certifications GOAL: Insert an accident tolerant fuel lead test assembly (LTA) or lead test rod (LTR) into a commercial reactor within ten years (i.e. by 2022). 13

14 LWR Accident Tolerant Fuels Fuels with enhanced accident tolerance are those that, in comparison with the standard UO 2 Zircaloy system, can tolerate loss of active cooling in the core for a considerably longer time period (depending on the LWR system and accident scenario) while maintaining or improving the fuel performance during normal operations. Improved Reaction Kinetics with Steam - Heat of oxidation - Oxidation rate Improved Fuel Properties - Lower operating temperatures - Clad internal oxidation - Fuel relocation / dispersion - Fuel melting High temperature during loss of active cooling Slower Hydrogen Generation Rate - Hydrogen bubble - Hydrogen explosion - Hydrogen embrittlement of the clad Improved Cladding Properties - Clad fracture - Geometric stability - Thermal shock resistance - Melting of the cladding Enhanced Retention of Fission Products -Gaseous fission products -Solid/liquid fission products 14

15 ATF must meet the LWR operations, safety and fuel cycle constraints BACKWARD COMPATIBILITY (qualified in an existing reactor) ECONOMICS Advanced Fuel Design, Operations and Safety Envelope FUEL CYCLE IMPACT IMPACT ON SAFETY (for the entire spectrum of DBAs +BDBA??) IMPACT ON OPERATIONS 15

16 Integration of Laboratory, Industry, and University ATF Efforts A series of three attribute and metrics meetings, National, International, and cladding-coating specific, has been completed DOE-Laboratory technical efforts in both fuel and cladding Fully ceramic microencapsulated fuel (ORNL), Enhanced UO 2 (LANL) FeCrAl cladding (ORNL), Mo-based cladding (LANL) Industry engagement via three Funding Opportunity Announcement projects initiated in 2012; development teams are led by: Westinghouse GE Global Research AREVA University engagement via three Independent Research Projects (IRPs) University of Illinois University of Tennessee Georgia Institute of Technology Engagement with NRC and Industry representative organizations 16

17 Performance ATF research and development working with industry partners towards technology selection GEN 2 GEN 3 and 3+ Near Term Technologies Molybdenum Claddings High Density Fuels (U 2 Si 3, UN, etc.) High Fission Product Retention Ceramic Claddings High Performance UO 2 Thin walled high strength steel alloy cladding Cladding Coatings Mid-Term Technologies Time to Deployment (years) 17

18 FCRD Advanced Fuels Campaign Accident Tolerant Fuel DOE-funded Industry Research Westinghouse General Atomics, Edison Welding Institute, LANL, INL, Texas A&M Univ, MIT, Southern Nuclear Operating Company Develop and test cladding concepts, such as SiC and SiC ceramic matrix composites or coated Zr alloys, and high density / high thermal conductivity fuel pellets, such as Uranium nitride-uranium silicides AREVA Univ of Wisconsin, Univ of Florida, Savannah River Nat Lab, TVA, Duke Concepts include UO 2 fuel with chromium dopant, the addition of SiC fibers to the doped pellets, and several coatings on Zirconium-alloy fuel claddings GE Global Research Global Nuclear Fuels, Univ of Michigan, LANL Develop ferritic / martensitic alloy cladding (no fuel development) 18

19 FCRD Advanced Fuels Campaign Accident Tolerant Fuel DOE-funded University Research University of Tennessee Penn State, Univ of Colorado, Univ of Michigan, LANL, Westinghouse, Oxford, Univ of Manchester, Univ of Sheffield, Univ of Huddersfield, ANSTO Ceramic coatings for cladding (no fuel development), including (i) MAX phase ceramic coatings and (ii) graded interface architecture (multilayer) ceramic coatings, using yttria-stabilized zirconia (YSZ) as the outer protective layer University of Illinois Univ of Michigan, Univ of Florida, INL, Univ of Manchester, ATI Wah Chang Engineered Zr alloy cladding (no fuel development); (i) application of a coating layer or (ii) modification of the bulk cladding composition to promote precipitation of minor phase(s) during fabrication Georgia Institute of Technology Univ of Michigan, Virginia Tech, Univ of Tennessee, Univ of Idaho, Morehouse College, INL, Westinghouse Electric, Southern Nuclear, Polytechnic Univ of Milan, Univ of Cambridge Integral Inherently Safe LWR (design concept) High power density technologies/components Compact core design achieved by using a non-oxide fuel form with improved heat removal capability, combined with fuel/clad design of enhanced accident tolerance 19

20 Fuels-relevant LWRS Work Scoping analyses for ATF concepts Normal operation (MOOSE-based BISON fuel performance code) Severe accident modeling (MELCOR) Probabilistic Risk Assessment (RISMC) Characterization and testing of selected advanced cladding concepts Characterization Initial focus on hybrid cladding design (Zirc-4 + SiC CMC overbraid) Development of test techniques (SiC CMC tubes; bend, corrosion and thermal stress tests) Use of laser-based techniques for thermal property measurement Support for ASTM standards development for CMCs Failure mode analysis for SiC CMCs Irradiation of UO 2 in SiC Triplex cladding 20 GWd irradiation, PIE preparations Diffusion couple study (SiC UO 2 at elevated temperature) SiC joining technology development for LWR service 20

21 ATF Modeling Activities: Scoping Analyses Scoping analyses to estimate potential performance improvements for ATF concepts under normal operating conditions, off-normal conditions and severe accidents. Normal operation (BISON) Severe Accidents (MELCOR) Scoping PRA Within LWRS Risk Informed Safety Margin Characterization scope Incorporation of MELCOR and BISON results to perform PRA 21

22 Oxidation Kinetics System (located at INL; out-of-pile) Designed to evaluate advanced cladding materials under simulated LOCA conditions Simulates nuclear fuel heating from inside-out via inductive coupling to susceptor rod inside cladding tubes Detects onset and measures evolution of oxidation in steam, steam/water, air, etc. via emissivity changes and mass spectrometry Evaluates deformation behavior (swelling/ballooning/rupture) of pressurized tubes Evaluates cladding heat transfer characteristics Characterizes thermal stress behavior during partial immersion and refill quenching System Design Partial immersion/ refill quenching Multiple Rodlets

23 Spatially Resolved Thermal Transport in SiC Composites Laser flash results for monolithic SiC (blue curve) and SiC CMC (red curve). The room temperature diffusivity of the matrix material, measured using MTR, is also reported. An optical micrograph of the surface of the sample used in the MTR study is shown in the inset. Spatially resolved thermal property data is crucial for meso-scale thermo-mechanical models Use Laser-based method (MTR) to isolate thermal properties of matrix Percolation of voids during CVI process determines density of matrix Percolation is strongly dependent on process parameters INL data shows that the thermal diffusivity of the matrix in the CMC material is considerably smaller than a monolithic material made using the same process 23

24 Development of LWR Accident Tolerant Fuel Metrics National and international workshops among experts in materials and reactor operations to develop consistent performance metrics for advanced LWR accident tolerant fuels National Workshop on Metrics Development for LWR ATF (Oct 2012) International Workshop on Metrics Development for LWR ATF (Dec 2012) Analyses will be performed to assess safety margin sensitivity to each design / performance parameter and to determine the potential impact of conceptual designs on the associated safety margin under accident conditions. Additional meeting held to discuss issues specific to coated cladding concepts (Feb 2013) Preparing report on overall metrics established for LWR ATF (Aug 2013) Comprehensive report compiled based on national and international workshops, cladding & coatings meeting, and other meetings held as necessary Will incorporate associated analysis results

25 Thank you! Questions? 25