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  1. Article ; Online: Heat-Generating Nuclear Waste in Salt

    Peter J. Johnson / Shawn Otto / Douglas J. Weaver / Brian Dozier / Terry A. Miller / Amy B. Jordan / Nathan G. Hayes-Rich / Philip H. Stauffer

    Vadose Zone Journal, Vol 18, Iss

    Field Testing and Simulation

    2019  Volume 1

    Abstract: Investigations relating to in-drift disposal of heat-generating nuclear waste in salt have raised questions about heat–brine interactions in the unsaturated run-of-mine (RoM) salt pile used as backfill. These interactions have the potential to change the ...

    Abstract Investigations relating to in-drift disposal of heat-generating nuclear waste in salt have raised questions about heat–brine interactions in the unsaturated run-of-mine (RoM) salt pile used as backfill. These interactions have the potential to change the structure of the RoM salt surrounding the canister, possibly altering long-term containment of the source. An experiment is in progress at the Waste Isolation Pilot Plant (WIPP), New Mexico, in which a heated canister was placed on the floor of an open drift, covered in a pile of RoM salt, and energized with 1000 W. Temperature in the RoM salt pile had stabilized after about 15 d, allowing evaluation of the heat-up period of the ongoing experiment. Using a multiphase porous flow simulator that has been modified to handle salt-specific coupled processes, we examined coupled thermal–hydrological–chemical behavior in the RoM salt pile. Our simulations suggest that for the relatively dry cases examined, porosity changes within RoM salt in a generic salt repository are likely to be minor in the period between waste emplacement and plastic closure of the drift. The primary sensitivity for porosity change is to the early moisture content of the RoM salt used to cover the canister. Secondary influences include moisture availability from the disturbed rock zone (DRZ) surrounding the drift and the capillary pressure ratio between the DRZ and the RoM salt. Early changes in porosity and permeability may be affected by moisture content, but this was not observed in the test. Such changes would be most likely to occur when using damp RoM salt or if waste is emplaced in a drift immediately following opening of the drift before evaporative dewatering of the drift walls occurs.
    Keywords Environmental sciences ; GE1-350 ; Geology ; QE1-996.5
    Language English
    Publishing date 2019-01-01T00:00:00Z
    Publisher Wiley
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: An Investigation of Plume Response to Soil Vapor Extraction and Hypothetical Drum Failure

    Hannah R. Behar / Emily E. Snyder / Stanislaw Marczak / Larry J. Salazar / Bobbie Rappe / Gerald F. Fordham / Shaoping P. Chu / Daniel M. Strobridge / Kay H. Birdsell / Terry A. Miller / Kent C. Rich / Philip H. Stauffer

    Vadose Zone Journal, Vol 18, Iss

    2019  Volume 1

    Abstract: Soil vapor extraction (SVE) has been used at sites across the Department of Energy complex, including sites where legacy subsurface wastes represent a potential source of groundwater contamination. At Los Alamos National Laboratory (LANL), leakage from ... ...

    Abstract Soil vapor extraction (SVE) has been used at sites across the Department of Energy complex, including sites where legacy subsurface wastes represent a potential source of groundwater contamination. At Los Alamos National Laboratory (LANL), leakage from waste drums buried at an inactive chemical waste site has created a subsurface vapor plume of volatile organic compounds (VOCs). Soil vapor extraction operation in 2015 and rebound testing through 2017 were successful in reducing the plume’s mass and mitigating VOC migration toward the water table. However, the possibility that waste drums could fail and release VOCs could pose a challenge in the future. To explore the impacts of drum failure, as well as the capabilities of SVE remediation, we simulated hypothetical contaminant release scenarios and subsequent SVE remediation. Three-dimensional subsurface VOC behavior, including advection, diffusion, and plume interactions with topography, were simulated using the porous flow simulator Finite Element Heat and Mass Transfer. Simulations of future site conditions have allowed identification of “sentry” boreholes that can be monitored for early detection in case of drum failure. Sentry boreholes can also be used to set concentration thresholds above which SVE should be initiated. For the LANL site, simulations show that SVE can be started 3 yr following drum failure and remain a viable remediation tool. More broadly, the principles outlined in this work can be used to support remediation planning at other subsurface waste sites. Predictive models of future releases can be analyzed to set concentration threshold values, guide selection of sentry boreholes, and increase operational efficiency.
    Keywords Environmental sciences ; GE1-350 ; Geology ; QE1-996.5
    Language English
    Publishing date 2019-02-01T00:00:00Z
    Publisher Wiley
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

    More links

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

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