Executive SummaryThe U.S. Department of Energy Office of Nuclear Energy, Office of Fuel Cycle Technology established the Used Fuel Disposition Campaign (UFDC) in fiscal year 2010 (FY10) to conduct the research and development (R&D) activities related to storage, transportation and disposal of used nuclear fuel and high level nuclear waste. The Mission of the UFDC isTo identify alternatives and conduct scientific research and technology development to enable storage, transportation and disposal of used nuclear fuel and wastes generated by existing and future nuclear fuel cycles.The work package of Crystalline Disposal R&D directly supports the following UFDC objectives: Develop a fundamental understanding of disposal system performance in a range of environments for potential wastes that could arise from future nuclear fuel cycle alternatives through theory, simulation, testing, and experimentation. Develop a computational modeling capability for the performance of storage and disposal options for a range of fuel cycle alternatives, evolving from generic models to more robust models of performance assessment.The objective of the Crystalline Disposal R&D Work Package is to advance our understanding of long-term disposal of used fuel in crystalline rocks and to develop necessary experimental and computational capabilities to evaluate various disposal concepts in such media.Significant progress has been made in FY14 in both experimental and modeling arenas in evaluation of used fuel disposal in crystalline rocks. The work covers a wide range of research topics identified in the R&D plan. The major accomplishments are summarized below: A R&D plan was developed for used fuel disposal in crystalline rocks. A total of 31 research topics (9 for system level and 22 for processes level) have been identified. The technical approach to addressing each of these topics is formulated. A generic reference case for crystalline disposal media has been established. The reference case specifies the emplacement concept, waste inventory, waste form, waste package, backfill/buffer properties, EBS failure scenarios, host rock properties, and biosphere. This is an important step in developing a baseline for total system model development. Three emplacement concepts were specified: waste packages containing 4 PWR assemblies emplaced in boreholes in the floors of horizontal tunnels (for comparison with the KBS-3 concept), a 12-assembly waste package emplaced in tunnels, and a 32-assembly dual purpose canister emplaced in tunnels. We have developed and applied THMC models to the analysis of coupled EBS processes in bentonite-backfilled repositories. We based this development on the extension of the Used Fuel Disposal in Crystalline Rocks vi 9/26/2014Used Fuel Disposal in Crystalline Rocks 9/26/2014 vii column method for evaluating and parameterizing colloid-facilitated radionuclide transport, using bentonite colloids, Am, and Grimsel Test Site granodiorite FFM as a model system. The method is designed to better interrogate the slowe...