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Monitoring and Repair of Cement-Geomaterial Interfaces in Borehole and Repository Scenarios

Matteo, Edward N.; McMahon, Kevin A.; Camphouse, Russell C.; Dewers, Thomas D.; Jove Colon, Carlos F.; Fuller, Timothy J.; Mohahgheghi, J.M.; Stormont, J.C.; Taha, M.T.; Pyrak-Nolte, L.P.; Wang, C.-F.; Douba, A.D.; Genedy, M.G.; Fernandez, S.G.; Kandil, U.F.; Soliman, E.E.; Starr, J.S.; Stenko, M.S.

The failure of subsurface seals (i.e., wellbores, shaft and drift seals in a deep geologic nuclear waste repository) has important implications for US Energy Security. The performance of these cementitious seals is controlled by a combination of chemical and mechanical forces, which are coupled processes that occur over multiple length scales. The goal of this work is to improve fundamental understanding of cement-geomaterial interfaces and develop tools and methodologies to characterize and predict performance of subsurface seals. This project utilized a combined experimental and modeling approach to better understand failure at cement-geomaterial interfaces. Cutting-edge experimental methods and characterization methods were used to understand evolution of the material properties during chemo-mechanical alteration of cement-geomaterial interfaces. Software tools were developed to model chemo-mechanical coupling and predict the complex interplay between reactive transport and solid mechanics. Novel, fit-for-purpose materials were developed and tested using fundamental understanding of failure processes at cement- geomaterial interfaces. ACKNOWLEDGEMENTS The authors wish to acknowledge the Earth Sciences Research Foundation for their generous support over the last three years. In particular, we thank Erik Webb for his numerous suggestions, comments, feedback, and encouragement over the course of the project. There many who helped bring this project to fruition, including: Dave Borns, Steve Bauer, Pania Newell, Heeho Park, and Doug Blankenship. There are many support personnel who we thank for their valuable contributions to the logistics and business of management side of the project, including: Tracy Woolever, Libby Sanzero, and Nancy Vermillion.

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Computational thermal, chemical, fluid, and solid mechanics for geosystems management

Martinez, Mario J.; Red-Horse, John R.; Carnes, Brian C.; Mesh, Mikhail M.; Field, Richard V.; Davison, Scott M.; Yoon, Hongkyu Y.; Bishop, Joseph E.; Newell, Pania N.; Notz, Patrick N.; Turner, Daniel Z.; Subia, Samuel R.; Hopkins, Polly L.; Moffat, Harry K.; Jove Colon, Carlos F.; Dewers, Thomas D.; Klise, Katherine A.

This document summarizes research performed under the SNL LDRD entitled - Computational Mechanics for Geosystems Management to Support the Energy and Natural Resources Mission. The main accomplishment was development of a foundational SNL capability for computational thermal, chemical, fluid, and solid mechanics analysis of geosystems. The code was developed within the SNL Sierra software system. This report summarizes the capabilities of the simulation code and the supporting research and development conducted under this LDRD. The main goal of this project was the development of a foundational capability for coupled thermal, hydrological, mechanical, chemical (THMC) simulation of heterogeneous geosystems utilizing massively parallel processing. To solve these complex issues, this project integrated research in numerical mathematics and algorithms for chemically reactive multiphase systems with computer science research in adaptive coupled solution control and framework architecture. This report summarizes and demonstrates the capabilities that were developed together with the supporting research underlying the models. Key accomplishments are: (1) General capability for modeling nonisothermal, multiphase, multicomponent flow in heterogeneous porous geologic materials; (2) General capability to model multiphase reactive transport of species in heterogeneous porous media; (3) Constitutive models for describing real, general geomaterials under multiphase conditions utilizing laboratory data; (4) General capability to couple nonisothermal reactive flow with geomechanics (THMC); (5) Phase behavior thermodynamics for the CO2-H2O-NaCl system. General implementation enables modeling of other fluid mixtures. Adaptive look-up tables enable thermodynamic capability to other simulators; (6) Capability for statistical modeling of heterogeneity in geologic materials; and (7) Simulator utilizes unstructured grids on parallel processing computers.

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Mesoscale to plant-scale models of nuclear waste reprocessing

Rao, Rekha R.; Pawlowski, Roger P.; Brotherton, Christopher M.; Cipiti, Benjamin B.; Domino, Stefan P.; Jove Colon, Carlos F.; Moffat, Harry K.; Nemer, Martin N.; Noble, David R.; O'Hern, Timothy J.

Imported oil exacerabates our trade deficit and funds anti-American regimes. Nuclear Energy (NE) is a demonstrated technology with high efficiency. NE's two biggest political detriments are possible accidents and nuclear waste disposal. For NE policy, proliferation is the biggest obstacle. Nuclear waste can be reduced through reprocessing, where fuel rods are separated into various streams, some of which can be reused in reactors. Current process developed in the 1950s is dirty and expensive, U/Pu separation is the most critical. Fuel rods are sheared and dissolved in acid to extract fissile material in a centrifugal contactor. Plants have many contacts in series with other separations. We have taken a science and simulation-based approach to develop a modern reprocessing plant. Models of reprocessing plants are needed to support nuclear materials accountancy, nonproliferation, plant design, and plant scale-up.

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8 Results
8 Results