U.S. Nuclear Waste Technical Review Board A Report to the U.S. Congress and the Secretary of Energy Filling the Gaps: The Critical Role of Underground Research Laboratories in the U.S. Department of Energy Geologic Disposal Research and Development Program January 2020 U.S. Nuclear Waste Technical Review Board FILLING THE GAPS: THE CRITICAL ROLE OF UNDERGROUND RESEARCH LABORATORIES IN THE U.S. DEPARTMENT OF ENERGY GEOLOGIC DISPOSAL RESEARCH AND DEVELOPMENT PROGRAM Report to the United States Congress and the Secretary of Energy January 2020 U.S. NUCLEAR WASTE TECHNICAL REVIEW BOARD JEAN M. BAHR, PH.D., CHAIR University of Wisconsin, Madison, Wisconsin STEVEN M. BECKER, PH.D. Old Dominion University, Norfolk, Virginia SUSAN L. BRANTLEY, PH.D. Pennsylvania State University, University Park, Pennsylvania ALLEN G. CROFF, NUCLEAR ENGINEER, M.B.A. Vanderbilt University, Nashville, Tennessee EFI FOUFOULA-GEORGIOU, PH.D. University of California Irvine, Irvine, California TISSA ILLANGASEKARE, PH.D., P.E. Colorado School of Mines, Golden, Colorado KENNETH LEE PEDDICORD, PH.D., P.E. Texas A&M University, College Station, Texas PAUL J. TURINSKY, PH.D. North Carolina State University, Raleigh, North Carolina MARY LOU ZOBACK, PH.D. Stanford University, Stanford, California iii U.S. NUCLEAR WASTE TECHNICAL REVIEW BOARD STAFF Executive Staff Nigel Mote Executive Director Neysa Slater-Chandler Director of Administration Senior Professional Staff Bret W. Leslie Geoscience, External Affairs Daniel G. Ogg Nuclear Engineering, Operations Roberto T. Pabalan Geochemistry, Physical Chemistry Administrative & Support Staff Davonya S. Barnes Information Systems Specialist Jayson S. Bright Systems Administrator Sonya Townsend Administrative Assistant Casey Waithe Financial Manager v vii viii ix CONTENTS ABBREVIATIONS AND ACRONYMS ....................................................................... xv ACKNOWLEDGMENTS ....................................................................................... xvii EXECUTIVE SUMMARY ....................................................................................... xix 1. INTRODUCTION ................................................................................................. 1 1.1 Board Workshop Agenda ..............................................................................................1 2. ROLE OF UNDERGROUND RESEARCH LABORATORIES IN ENHANCING INTERNATIONAL KNOWLEDGE AND EXPERIENCE ............................................. 9 2.1 Why an Underground Laboratory? ...............................................................................9 2.2 Site Specific versus Generic Underground Research Laboratories ............................11 2.3 Lessons Learned from the International Experience ..................................................13 2.4 Steps Toward a Successful Repository Program ........................................................15 2.5 Observations and Recommendations Relevant to DOE’s International Collaboration Program ................................................................................................16 3. RESEARCH INTO COMPLEX COUPLED PROCESSES ........................................... 19 3.1 Modeling .....................................................................................................................22 3.2 Near-field Perturbation and Engineered Barrier Integrity ..........................................27 3.3 Flow and Radionuclide Transport ...............................................................................34 3.4 Microbial Processes ....................................................................................................36 4. USING INTEGRATED MODELING FOR THE SAFETY CASE AND GAP ANALYSIS ............................................................................................... 39 5. CRITICAL ROLE OF UNDERGROUND RESEARCH LABORATORIES IN TECHNOLOGY DEVELOPMENT AND DEMONSTRATION, TRAINING, AND PUBLIC CONFIDENCE BUILDING ..................................................................... 43 5.1 Developing and Demonstrating Technology and Construction and Operational Capabilities ..............................................................................................43 5.2 Training the Next Generation of Researchers .............................................................44 5.3 Public Outreach and Other Research Applications .....................................................45 6. NEW FRONTIERS AND MONITORING DURING OPERATION AND POST-CLOSURE .............................................................................................. 47 7. CONCLUSIONS, FINDINGS, AND RECOMMENDATIONS ..................................... 49 REFERENCES ...................................................................................................... 53 GLOSSARY .......................................................................................................... 59 APPENDIX A: SPRING 2019 WORKSHOP AGENDA ............................................. A-1 Contents xi FIGURES, TABLES, AND BOXES FIGURES Figure 1-1. Photo of a mold SKB used for making ring-shaped bentonite blocks ...............4 Figure 1-2. Schematic showing the DOE URL-based R&D activities addressing priority R&D topics by rock type and repository position ................................6 Figure 2-1. Repeated testing at the Äspö URL enabled Sweden’s waste disposal program to advance from technology readiness level (TRL) 4 to 7 ................15 Figure 3-1. The eleven directly coupled THMC processes associated with a nuclear waste repository in fractured rock as conceptualized in current models .........20 Figure 3-2. Holtec Hi-Star 100 dry storage systems each containing a dual-purpose canister .............................................................................................................21 Figure 3-3. Process of iterative learning from laboratory experiments, modeling, and field observations .............................................................................................22 Figure 3-4. Spatial upscaling and temporal extrapolation ..................................................25 Figure 3-5. Integration of URL results as a part of safety case methodology ....................26 Figure 3-6. (a) Short term (0 to 10,000 years) thermally driven coupled THM processes and (b) long term (10,000 to 100,000 years) impact of coupled THM processes ...................................................................................28 Figure 3-7. Temporal evolution of thermal, hydrologic, mechanical, and chemical changes in a bentonite engineered barrier system ............................................28 Figure 3-8. Conceptualization of gas transport mechanisms in clay ..................................32 Figure 4-1. Components of DOE’s Geologic Disposal Safety Assessment Framework .......................................................................................................39 TABLES Table 1-1. DOE disposal R&D program priority topics .....................................................5 Table 2-1. List of some generic and site-specific URLs ...................................................10 BOXES Box 1-1. Bentonite and its use as an engineered barrier material .....................................4 Box 1-2. Coupled thermal-hydrological-mechanical-chemical processes and microbial effects.................................................................................................7 Box 3-1. Direct geologic disposal of large spent nuclear fuel canisters .........................21 Box 3-2. Constitutive models of bentonite behavior ......................................................29 Figures, Tables, and Boxes xiii ABBREVIATIONS AND ACRONYMS ALC high-level waste disposal cell experiment, Bure URL, France Andra National Radioactive Waste Management Agency, France BATS Brine Availability Test in Salt experiment, WIPP, New Mexico, USA BRIE Bentonite Rock Interaction Experiment, Äspö Hard Rock Laboratory, Sweden CFM Colloid Formation and Migration project, Grimsel Test Site, Switzerland CHM chemical-hydrological-mechanical CI Cement clay Interaction experiment, Mont Terri URL, Switzerland DECOVALEX DEvelopment of COupled Models and their VALidation Against Experiments DOE Department of Energy, USA DOE-NE DOE Office of Nuclear Energy EBS Engineered Barrier System experiment, Honorobe URL, Japan FE Full-scale Emplacement experiment, Mont Terri URL, Switzerland FEBEX Full-scale Engineered Barrier Experiment, Grimsel Test Site, Switzerland FORGE Fate Of Repository GasEs project FS Fault Slip experiment, Mont Terri URL, Switzerland GDSA Geologic Disposal Safety Assessment GREET Groundwater REcovery Experiment in a Tunnel, Mizunami URL, Japan HADES High Activity Disposal Experimental Site, Mol URL, Belgium HE-E in situ heater test experiment, Mont Terri URL, Switzerland HG-A gas path through host rock and along seals experiment, Mont Terri URL, Switzerland HLW high-level radioactive waste HotBENT full-scale high-temperature heater test, Grimsel Test Site, Switzerland LANL Los Alamos National Laboratory, USA LASGIT LArge Scale Gas Injection Test, Äspö Hard Rock Laboratory, Sweden LBNL Lawrence Berkeley National Laboratory, USA LTDE Long-Term Diffusion sorption Experiment, Äspö Hard Rock Laboratory, Sweden MaCoTe Material Corrosion Test, Grimsel Test Site, Switzerland Nagra National Cooperative for the Disposal of Radioactive Waste, Switzerland PFLOTRAN an open-source multi-physics simulator R&D research and development