Mechanical response and microprocesses of reconsolidating crushed salt at elevated temperature

Broome, S. T.; Bauer, S. J.; Hansen, F. D.; Mills, M. M.

doi:10.1007/s00603-015-0840-9

Title: Mechanical response and microprocesses of reconsolidating crushed salt at elevated temperature

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Abstract

Design, analysis and performance assessment of potential salt repositories for heat-generating nuclear waste require knowledge of thermal, mechanical, and fluid transport properties of reconsolidating granular salt. So, to inform salt repository evaluations, we have undertaken an experimental program to determine Bulk and Young’s moduli and Poisson’s ratio of reconsolidated granular salt as a function of porosity and temperature and to establish the deformational processes by which the salt reconsolidates. Our tests were conducted at 100, 175, and 250 °C. In hydrostatic tests, confining pressure is increased to 20 MPa with periodic unload/reload loops to determine K. Volume strain increases with increasing temperature. In shear tests at 2.5 and 5 MPa confining pressure, after confining pressure is applied, the crushed salt is subjected to a differential stress, with periodic unload/reload loops to determine E and ν. At predetermined differential stress levels the stress is held constant and the salt consolidates. Displacement gages mounted on the samples show little lateral deformation until the samples reach a porosity of ~10 %. Interestingly, vapor is vented only for 250 °C tests and condenses at the vent port. It is hypothesized that the brine originates from fluid inclusions, which were made accessible by heating andmore »« less

Authors:

Broome, S. T. ^[1]; Bauer, S. J. ^[1]; Hansen, F. D. ^[1]; Mills, M. M. ^[1]

Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Publication Date:: Mon Sep 14 00:00:00 EDT 2015

Research Org.:: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Sponsoring Org.:: USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:: 1236213

Alternate Identifier(s):: OSTI ID: 1238586

Report Number(s):: SAND-20151569J; SAND-2015-7324J
Journal ID: ISSN 0723-2632; PII: 840

Grant/Contract Number:: AC04-94AL85000

Resource Type:: Accepted Manuscript

Journal Name:: Rock Mechanics and Rock Engineering

Additional Journal Information:: Journal Volume: 48; Journal Issue: 6; Journal ID: ISSN 0723-2632

Publisher:: Springer

Country of Publication:: United States

Language:: English

Subject:: 58 GEOSCIENCES; crushed salt reconsolidation; mechanical testing; high temperature; hydrostatic; triaxial; salt creep; elastic properties

Citation Formats


                    Broome, S. T., Bauer, S. J., Hansen, F. D., and Mills, M. M. Mechanical response and microprocesses of reconsolidating crushed salt at elevated temperature.  United States: N. p., 2015. 
Web.  doi:10.1007/s00603-015-0840-9.

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                    Broome, S. T., Bauer, S. J., Hansen, F. D., & Mills, M. M. Mechanical response and microprocesses of reconsolidating crushed salt at elevated temperature.  United States.  https://doi.org/10.1007/s00603-015-0840-9

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                    Broome, S. T., Bauer, S. J., Hansen, F. D., and Mills, M. M. Mon .  
"Mechanical response and microprocesses of reconsolidating crushed salt at elevated temperature".  United States.  https://doi.org/10.1007/s00603-015-0840-9.  https://www.osti.gov/servlets/purl/1236213.

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@article{osti_1236213,

  title        = {Mechanical response and microprocesses of reconsolidating crushed salt at elevated temperature},

  author       = {Broome, S. T. and Bauer, S. J. and Hansen, F. D. and Mills, M. M.},

  abstractNote = {Design, analysis and performance assessment of potential salt repositories for heat-generating nuclear waste require knowledge of thermal, mechanical, and fluid transport properties of reconsolidating granular salt. So, to inform salt repository evaluations, we have undertaken an experimental program to determine Bulk and Young’s moduli and Poisson’s ratio of reconsolidated granular salt as a function of porosity and temperature and to establish the deformational processes by which the salt reconsolidates. Our tests were conducted at 100, 175, and 250 °C. In hydrostatic tests, confining pressure is increased to 20 MPa with periodic unload/reload loops to determine K. Volume strain increases with increasing temperature. In shear tests at 2.5 and 5 MPa confining pressure, after confining pressure is applied, the crushed salt is subjected to a differential stress, with periodic unload/reload loops to determine E and ν. At predetermined differential stress levels the stress is held constant and the salt consolidates. Displacement gages mounted on the samples show little lateral deformation until the samples reach a porosity of ~10 %. Interestingly, vapor is vented only for 250 °C tests and condenses at the vent port. It is hypothesized that the brine originates from fluid inclusions, which were made accessible by heating and intragranular deformational processes including decrepitation. Furthermore, identification and documentation of consolidation processes are inferred from optical and scanning electron microstructural observations. As a result, densification at low porosity is enhanced by water film on grain boundaries that enables solution-precipitation phenomena.},

  doi          = {10.1007/s00603-015-0840-9},

  journal      = {Rock Mechanics and Rock Engineering},

  number       = 6,

  volume       = 48,

  place        = {United States},

  year         = {Mon Sep 14 00:00:00 EDT 2015},

  month        = {Mon Sep 14 00:00:00 EDT 2015}

}

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