A comparative application of the Repository Integration Program (RIP) to Total System Performance Assessment, 1991

During Fiscal Year (FY) 1991 and FY 1992, Sandia National Laboratory and Battelle Pacific Northwest Laboratory were assigned the responsibility to generate initial Total System Performance Assessments (TSPAs) of the Yucca Mountain site. The analyses performed by these organizations (called TSPA-1991) are reported in Barnard et al(1992) and Eslinger et al. (1993). During this same time period, Golder Associates Inc. was assigned the task of generating a model capable of analyzing the total system performance of a high-level radioactive waste repository. The developed model, called Repository Integration Program (RIP), is documented in Kossik and Hachey (1993), Miller et al. (1993), and Golder Associates Inc. (1993). In FY 1993, the Civilian Radioactive Waste Management System Contractor was assigned the responsibility to plan, coordinate, and contribute to the second iteration of TSPA-2. Prior to initiating the next TSPA iteration, it was decided that it would be valuable to evaluate the applicability of RIP for use in this iteration. Therefore, analyses were conducted to compare the results generated by RIP to those reported in TSPA-1991. In particular, the aim was to generate a RIP input data set as equivalent as possible to that documented in Barnard et al. (1992) and to analyze the total system performance (as well as the performance of the individual subsystem components of the waste package/Engineered Barrier System (EBS), unsaturated gaseous flow and transport, unsaturated aqueous flow and transport, saturated flow and transport, and disruptive processes/events). The performance measure for comparison with the results of TSPA-1991 is the cumulative release of radionuclides to the accessible environment over a 10,000-year period following closure normalized to the US Environmental Protection Agency (EPA) release limits specified in 40 CFR 191