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Determination of factors influencing radionuclide transport in fractured crystalline rock

International High-Level Radioactive Waste Management 2019, IHLRWM 2019

Hadgu, Teklu H.; Kalinina, Elena A.; Wang, Yifeng

Numerical modeling of flow and transport through fractured crystalline rock was conducted to identify major factors that affect migration of radionuclides from a high-level nuclear waste repository. The study was based on data collected at the Mizunami Underground Research Laboratory (URL) in Japan. Distributions of fracture parameters were used to generate a selected number of DFN realizations. For each realization the DFN was upscaled to a continuum mesh to provide permeability and porosity fields. The upscaled permeability and porosity fields were then used to study flow and transport through the fractured rock in a site-scale domain. For the present study the focus is on the effect of domain size and on upscaling of DFN to a continuum system. Simulation results and analysis on various upscaling and boundary condition assumptions are presented.

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TYPE Conference Poster YEAR 2019
ScopusOSTI

FY 18 Status Report on the Computing Systems for the Yucca Mountain Project TSPA-LA Models and Inventory of Software used for Process Models

Hadgu, Teklu H.; Appel, Gordon J.; Garland, Jason P.

Sandia National Laboratories (SNL) continued evaluation of total system performance assessment (TSPA) computing systems for the previously considered Yucca Mountain Project (YMP). This was done to maintain the operational readiness of the computing infrastructure (computer hardware and software) and knowledge capability for total system performance assessment (TSPA) type analysis, as directed by the National Nuclear Security Administration (NNSA), DOE 2010. This work is a continuation of the ongoing readiness evaluation reported in Lee and Hadgu (2014), Hadgu et al. (2015) and Hadgu and Appel (2016), and Hadgu et al. (2017). The TSPA computing hardware (2014 server cluster -CL2014) and storage system described in Hadgu et al. (2015) were used for the current analysis. One floating license of Gold Sim with Versions 9.60.300, 10.5, 11.1 and 12.0 was installed on the cluster head node, and its distributed processing capability was mapped on the cluster processors. Other supporting software were tested and installed to support the TSPA-type analysis on the server cluster. The FY18 task included developing an inventory of software used for the Yucca Mountain Project process models and preliminary assessment of status of the software; enhancing security of the cluster and setting a backup system. The 2014 server cluster and supporting software systems are fully operational to support TSPA-LA type analysis. 3 ACKNOWLEDGEMENTS The authors would like to express their gratitude to Tito Bonano (8840) and Kevin McMahon (8842) for their technical interest and programmatic support. The authors would also like to thank David Sassani (8842) for technical review of the report. 4

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TYPE SAND Report YEAR 2018
OSTIDOI

Evaluation of Engineered Barrier Systems in the Disposition of Spent Nuclear Fuel

Matteo, Edward N.; Hadgu, Teklu H.; Zheng, Liange Z.; Xu, Hao X.; Fox, Patricia F.; Nico, Peter N.; Birkholzer, Jens T.; Caporuscio, Florie C.; Sauer, Kirsten B.; Rock, M.J.; Houser, L.M.

This document is a summary of the R&D activities associated with the Engineered Barrier Systems Work Package. Multiple facets of Engineered Barrier Systems (EBS) research were examined in the course of FY18 activities. This report is focused on delvering an update on the status and progress of modelling tools and experimental methods, both of which are essential to understanding and predicting long-term repository performance as part of the safety case. Specifically, the work described herein aims to improve understanding of EBS component evolution and interactions. Utlimately, the EBS Work Package is working towards producing process models for distinct processes that can either be incorporated into performance assessment (PA), or provide critical information for implementing better contraints on barrier performance The main objective of this work is that the models being developed and refined will either be implemented directly into the Genreric Disposal System Analysis platform (GDSA), or can otherwise be indirectly linked to the performance assessment by providing improved bounding conditions. In either the case, the expectation is that validated modelling tools will be developed that provide critical input to the safety case. This report covers a range of topics — modelling topics include: thermal-hydrologic-mechnicalchemical coupling (THMC) in buffer materials, comparisons of modelling approaches to optimize computational efficiency, thermal analysis for EBS/repository design, benchmarking of thermal analysis tools, and a preliminary study of buffer re-saturation processess. Experimental work reported, includes: chemical evolution and sorption behavior of clay-based buffer materials and high-pressure, high temperature studies of EBS material interactions. The work leverages international collaborations to ensure that the DOE program is active and abreast of the latest advances in nuclear waste disposal. This includes participation in the HotBENT Field Test, aimed at understanding near-field effects on EBS materials at temperatures above 100 °C, and the analysis of data and characterization of samples from the FEBEX Field Test. Both the FEBEX and HotBENT Field Tests utilize/utilized the Grimsel Test Site in Switzerland, which is situated in a granite host rock. These tests offer the opportunity to understand near field evolution of bentonite buffer at in situ conditions for either a relatively long timescale (18 years for FEBEX) or temperature above 100 °C (HotBENT). Overall, this report provides in depth descriptions of tools and capabilities to investigate nearfield performance of EBS materials (esp. bentonite buffer), as well as tools for drift-scale thermal and thermal-hydrologic analysis critical to EBS and repository design. For a more detailed description of work contained herein, please see Section 10 ("Conclusions") of this document.

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TYPE Other Report YEAR 2018
OSTIDOI

US Sections Prepared for Future NEA Crystalline Club (CRC) Report on Status of R&D in CRC Countries Investigating Deep Geologic Disposal in Crystalline Rock

Mariner, Paul M.; Stein, Emily S.; Kalinina, Elena A.; Hadgu, Teklu H.; Jove Colon, Carlos F.; Basurto, Eduardo B.

U.S. knowledge in deep geologic disposal in crystalline rock is advanced and growing. U.S. status and recent advances related to crystalline rock are discussed throughout this report. Brief discussions of the history of U.S. disposal R&D and the accumulating U.S. waste inventory are presented in Sections 3.x.2 and 3.x.3. The U.S. repository concept for crystalline rock is presented in Section 3.x.4. In Chapters 4 and 5, relevant U.S. research related to site characterization and repository safety functions are discussed. U.S. capabilities for modelling fractured crystalline rock and performing probabilistic total system performance assessments are presented in Chapter 6.

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TYPE Other Report YEAR 2018
OSTIDOI
Results 26–50 of 109
Results 26–50 of 109