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Title: Reinvestigation into Closure Predictions of Room D at the Waste Isolation Pilot Plant

Abstract

Room D was an in-situ, isothermal, underground experiment conducted at theWaste Isolation Pilot Plant between 1984 and 1991. The room was carefully instrumented to measure the horizontal and vertical closure immediately upon excavation and for several years thereafter. Early finite element simulations of salt creep around Room D under predicted the vertical closure by 4.5×, causing investigators to explore a series of changes to the way Room D was modeled. Discrepancies between simulations and measurements were resolved through a series of adjustments to model parameters, which were openly acknowledged in published reports. Interest in Room D has been rekindled recently by the U.S./German Joint Project III and Project WEIMOS, which seek to improve the predictions of rock salt constitutive models. Joint Project participants calibrate their models solely against laboratory tests, and benchmark the models against underground experiments, such as room D. This report describes updating legacy Room D simulations to today’s computational standards by rectifying several numerical issues. Subsequently, the constitutive model used in previous modeling is recalibrated two different ways against a suite of new laboratory creep experiments on salt extracted from the repository horizon of the Waste Isolation Pilot Plant. Simulations with the new, laboratory-based, calibrations under predictmore » Room D vertical closure by 3.1×. A list of potential improvements is discussed.« less

Authors:
 [1]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1330187
Report Number(s):
SAND2016-9961
648142
DOE Contract Number:
AC04-94AL85000
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES

Citation Formats

Reedlunn, Benjamin. Reinvestigation into Closure Predictions of Room D at the Waste Isolation Pilot Plant. United States: N. p., 2016. Web. doi:10.2172/1330187.
Reedlunn, Benjamin. Reinvestigation into Closure Predictions of Room D at the Waste Isolation Pilot Plant. United States. doi:10.2172/1330187.
Reedlunn, Benjamin. 2016. "Reinvestigation into Closure Predictions of Room D at the Waste Isolation Pilot Plant". United States. doi:10.2172/1330187. https://www.osti.gov/servlets/purl/1330187.
@article{osti_1330187,
title = {Reinvestigation into Closure Predictions of Room D at the Waste Isolation Pilot Plant},
author = {Reedlunn, Benjamin},
abstractNote = {Room D was an in-situ, isothermal, underground experiment conducted at theWaste Isolation Pilot Plant between 1984 and 1991. The room was carefully instrumented to measure the horizontal and vertical closure immediately upon excavation and for several years thereafter. Early finite element simulations of salt creep around Room D under predicted the vertical closure by 4.5×, causing investigators to explore a series of changes to the way Room D was modeled. Discrepancies between simulations and measurements were resolved through a series of adjustments to model parameters, which were openly acknowledged in published reports. Interest in Room D has been rekindled recently by the U.S./German Joint Project III and Project WEIMOS, which seek to improve the predictions of rock salt constitutive models. Joint Project participants calibrate their models solely against laboratory tests, and benchmark the models against underground experiments, such as room D. This report describes updating legacy Room D simulations to today’s computational standards by rectifying several numerical issues. Subsequently, the constitutive model used in previous modeling is recalibrated two different ways against a suite of new laboratory creep experiments on salt extracted from the repository horizon of the Waste Isolation Pilot Plant. Simulations with the new, laboratory-based, calibrations under predict Room D vertical closure by 3.1×. A list of potential improvements is discussed.},
doi = {10.2172/1330187},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2016,
month =
}

Technical Report:

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  • Room D was an in-situ, isothermal, underground experiment conducted at the Waste Isolation Pilot Plant between 1984 and 1991. The room was carefully instrumented to measure the horizontal and vertical closure immediately upon excavation and for several years thereafter. Early finite element simulations of salt creep around Room D under-predicted the vertical closure by 4.5×, causing investigators to explore a series of changes to the way Room D was modeled. Discrepancies between simulations and measurements were resolved through a series of adjustments to model parameters, which were openly acknowledged in published reports. Interest in Room D has been rekindled recentlymore » by the U.S./German Joint Project III and Project WEIMOS, which seek to improve the predictions of rock salt constitutive models. Joint Project participants calibrate their models solely against laboratory tests, and benchmark the models against underground experiments, such as room D. This report describes updating legacy Room D simulations to today’s computational standards by rectifying several numerical issues. Subsequently, the constitutive model used in previous modeling is recalibrated two different ways against a suite of new laboratory creep experiments on salt extracted from the repository horizon of the Waste Isolation Pilot Plant. Simulations with the new, laboratory-based, calibrations under-predict Room D vertical closure by 3.1×. A list of potential improvements is discussed.« less
  • Pretest 3-D finite element calculations have been performed on the wedge pillar portion of the WIPP Geomechanical Evaluation Experiment. The wedge pillar separates two drifts that intersect at an angle of 7.5/sup 0/. Purpose of the experiment is to provide data on the creep behavior of the wedge and progressive failure at the tip. The first set of calculations utilized a symmetry plane on the center-line of the wedge which allowed treatment of the entire configuration by modeling half of the geometry. Two 3-D calculations in this first set were performed with different drift widths to study the influence ofmore » drift size on closure and maximum stress. A cross-section perpendicular to the wedge was also analyzed with 2-D finite element models and the results compared to the 3-D results. In another set of 3-D calculations both drifts were modeled but with less distance between the drifts and the outer boundaries. Results of these calculations are compared with results from the other calculations to better understand the influence of boundary conditions.« less
  • As part of the Waste Isolation Pilot Plant (WIPP) research and development program, a gas testing program has been developed to investigate the naturally occurring gases in the WIPP horizon rocks, and to evaluate their effect on the safe operations and performance of WIPP. This report presents a comparison of the structural response (closure and closure rates) of a drift drilled with pressure relief holes to the structural response of a drift drilled without pressure relief holes. The drifts under consideration are the E300 drift (mined with pressure relief holes) and the W170 drift (mined without pressure relief holes) locatedmore » south of the waste handling shaft. For the short-term (less than two years), differences between measured closures for the two drifts are negligible. The closure rate comparisons also indicate that the two drifts, thus far, are responding similarly.« less
  • The current model for brine inflow to Waste Isolation Pilot Plant (WIPP) excavations is consistent with the body of existing data for brine accumulations in WIPP underground test boreholes. Values for the model parameters are also consistent with independent measurements of brine and host rock salt properties. Experiments to provide additional tests of the assumptions and parameters in the model have been proposed, and the NAS WIPP Panel has strongly encouraged these tests. The Panel particularly urged a test of brine inflow into a relatively large room with a curved vertical cross-section, arguing that the curvature may minimize loss ofmore » inflowing brine to separations or cracks that are known to develop below the flat floors of existing rectangular rooms. The brine inflow room in this test plan responds to the urging of theWIPP panel. This test plan is intended as a working document. It is a plan for measurements of brine inflow, pore pressure, humidity, gas inflow, closure, disturbed rock zone (DRZ) characteristics, and other pre- and post-test analyses in Room Q of the Waste Isolation Pilot Plant (WIPP) experimental area.« less
  • The purpose of this report is to summarize for the record the objectives, planning, progress, and documentation of excavating Brine Inflow Room Q and implementing an initial set of Room Q tests. The Room Q tests were designed primarily to test the scale-up accuracy of the current brine inflow model by providing data on brine flow from the host rock salt to a large-scale excavation in the Waste Isolation Pilot Plant (WIPP). Data from these tests will also be used to reduce uncertainties in flow parameters and evaluate proposed mechanistic models. Room Q was excavated with a tunnel boring machine.more » The initial tests were implemented to measure brine flow parameters and room closure. Pore pressure, permeability, and brine inflow were measured with 15 tools emplaced in boreholes above, below, and on the north side of the room at a station 75 feet into the host rock from the entrance to the room. These measurements were made before, during, and after Room Q was bored to obtain data on the responses in the host rock to the boring process. Closure measurements were started almost immediately after excavation progressed past each measurement station. The designs, timing, sequence, procedures, and as-built records for these tests were documented in Sandia National Laboratories WIPP Quality Assurance files and Westinghouse WIPP Engineering records. 21 refs., 5 figs., 5 tabs.« less