Dr. S. David Sevougian is recently retired from Sandia National Laboratories, where he worked on nuclear engineering R Address: Sandia National Laboratories
Development of an enhanced performance assessment (PA) capability for geologic disposal of spent ... more Development of an enhanced performance assessment (PA) capability for geologic disposal of spent nuclear fuel and high-level waste has been ongoing for several years in the U.S. repository program. The new Generic Disposal System Analysis (GDSA) modeling and software framework is intended to be flexible enough to evolve through the various phases of repository activities, beginning with generic PA activities in the current Concept Evaluation phase to site-specific PA modeling in the Repository Development phase. The GDSA Framework utilizes modern software and hardware capabilities by being based on open-source software architecture and being configured to run in a massively parallel, high-performance computing (HPC) environment. It consists of two main components, the open-source Dakota uncertainty sampling and analysis software and the PFLOTRAN reactive multi-phase flow and transport simulator. Reference cases or “generic repositories” have been, and are being developed, based on t...
This paper describes advances in performance assessment modeling of deep geologic repositories fa... more This paper describes advances in performance assessment modeling of deep geologic repositories facilitated by a massively parallel, high-performance computing (HPC) environment. Our new Generic Disposal System Analysis (GDSA) Framework utilizes the massively parallel PFLOTRAN multi-physics code to simulate repository performance in the presence of coupled thermal-hydrologic-chemical processes, linked to DAKOTA, an HPC uncertainty sampling and propagation code that provides nested parallelism for multi-realization performance assessment and sensitivity analysis. This enhanced performance assessment (PA) modeling capability is demonstrated with deterministic and probabilistic simulations of a generic repository for SNF and HLW in bedded salt host rock, by comparing repository performance between a case with heat-generating waste (“thermal” case) and a case without heat generation (“isothermal” case). The simulation results provide preliminary insights into the effect of multi-physics ...
10th International Conference on Nuclear Engineering, Volume 4, 2002
The total-system performance assessment (TSPA) model for the final environmental impact statement... more The total-system performance assessment (TSPA) model for the final environmental impact statement (FEIS) for the potential high-level nuclear-waste repository at Yucca Mountain, Nevada was developed from a series of analyses and model studies of the Yucca Mountain site. The U.S. Department of Energy (DOE) has recommended the Yucca Mountain, Nevada site for the potential development of a geologic repository for the disposal of high-level radioactive waste and spent nuclear fuel. In May 2001, the DOE released the Yucca Mountain Science and Engineering Report (S&ER) for public review and comment. The S&ER summarizes more than 20 years of scientific and engineering studies supporting the site recommendation (SR). Following internal reviews of the S&ER and other documents, the DOE performed supplemental analyses of uncertainty in support of the SR as summarized in the Supplemental Science and Performance Analysis (SSPA) reports [2, 3]. The SSPA (1) provided insights into the impact of ne...
A methodology was developed to determine the effectiveness of different components/barriers in is... more A methodology was developed to determine the effectiveness of different components/barriers in isolating waste from the accessible environment for the potential nuclear waste repository at Yucca Mountain, Nevada [1]. Quantifying the performance offered by different barriers aids in prioritizing the testing and analysis activities aimed at resolving uncertainty in processes and parameters of greatest significance to long-term performance. If a substantial fraction of the overall performance of a repository system may be attributed to the performance of a particular barrier, then it is prudent to devote the necessary resources toward enhancing the confidence in our predictive ability regarding that barrier (through more in-depth characterization and testing).
Diffusive conductance for bifurcation of diffusive flux from a single continuum to a dual continu... more Diffusive conductance for bifurcation of diffusive flux from a single continuum to a dual continuum. ... Mehta, Sunil (Framatome ANP, Raleigh, NC) ; Sevougian, S. David ; Lord, Michael E. ... Conference: Proposed for presentation at the 3rd Annual GoldSim User conference ...
The Energy Citations Database (ECD) provides access to historical and current research (1948 to t... more The Energy Citations Database (ECD) provides access to historical and current research (1948 to the present) from the Department of Energy (DOE) and predecessor agencies.
Development of an enhanced performance assessment (PA) capability for geologic disposal of spent ... more Development of an enhanced performance assessment (PA) capability for geologic disposal of spent nuclear fuel and high-level waste has been ongoing for several years in the U.S. repository program. The new Generic Disposal System Analysis (GDSA) modeling and software framework is intended to be flexible enough to evolve through the various phases of repository activities, beginning with generic PA activities in the current Concept Evaluation phase to site-specific PA modeling in the Repository Development phase. The GDSA Framework utilizes modern software and hardware capabilities by being based on open-source software architecture and being configured to run in a massively parallel, high-performance computing (HPC) environment. It consists of two main components, the open-source Dakota uncertainty sampling and analysis software and the PFLOTRAN reactive multi-phase flow and transport simulator. Reference cases or “generic repositories” have been, and are being developed, based on t...
This paper describes advances in performance assessment modeling of deep geologic repositories fa... more This paper describes advances in performance assessment modeling of deep geologic repositories facilitated by a massively parallel, high-performance computing (HPC) environment. Our new Generic Disposal System Analysis (GDSA) Framework utilizes the massively parallel PFLOTRAN multi-physics code to simulate repository performance in the presence of coupled thermal-hydrologic-chemical processes, linked to DAKOTA, an HPC uncertainty sampling and propagation code that provides nested parallelism for multi-realization performance assessment and sensitivity analysis. This enhanced performance assessment (PA) modeling capability is demonstrated with deterministic and probabilistic simulations of a generic repository for SNF and HLW in bedded salt host rock, by comparing repository performance between a case with heat-generating waste (“thermal” case) and a case without heat generation (“isothermal” case). The simulation results provide preliminary insights into the effect of multi-physics ...
10th International Conference on Nuclear Engineering, Volume 4, 2002
The total-system performance assessment (TSPA) model for the final environmental impact statement... more The total-system performance assessment (TSPA) model for the final environmental impact statement (FEIS) for the potential high-level nuclear-waste repository at Yucca Mountain, Nevada was developed from a series of analyses and model studies of the Yucca Mountain site. The U.S. Department of Energy (DOE) has recommended the Yucca Mountain, Nevada site for the potential development of a geologic repository for the disposal of high-level radioactive waste and spent nuclear fuel. In May 2001, the DOE released the Yucca Mountain Science and Engineering Report (S&ER) for public review and comment. The S&ER summarizes more than 20 years of scientific and engineering studies supporting the site recommendation (SR). Following internal reviews of the S&ER and other documents, the DOE performed supplemental analyses of uncertainty in support of the SR as summarized in the Supplemental Science and Performance Analysis (SSPA) reports [2, 3]. The SSPA (1) provided insights into the impact of ne...
A methodology was developed to determine the effectiveness of different components/barriers in is... more A methodology was developed to determine the effectiveness of different components/barriers in isolating waste from the accessible environment for the potential nuclear waste repository at Yucca Mountain, Nevada [1]. Quantifying the performance offered by different barriers aids in prioritizing the testing and analysis activities aimed at resolving uncertainty in processes and parameters of greatest significance to long-term performance. If a substantial fraction of the overall performance of a repository system may be attributed to the performance of a particular barrier, then it is prudent to devote the necessary resources toward enhancing the confidence in our predictive ability regarding that barrier (through more in-depth characterization and testing).
Diffusive conductance for bifurcation of diffusive flux from a single continuum to a dual continu... more Diffusive conductance for bifurcation of diffusive flux from a single continuum to a dual continuum. ... Mehta, Sunil (Framatome ANP, Raleigh, NC) ; Sevougian, S. David ; Lord, Michael E. ... Conference: Proposed for presentation at the 3rd Annual GoldSim User conference ...
The Energy Citations Database (ECD) provides access to historical and current research (1948 to t... more The Energy Citations Database (ECD) provides access to historical and current research (1948 to the present) from the Department of Energy (DOE) and predecessor agencies.
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