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U.S. Department of Energy
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Recommendation for the Lower Limit of the Waste Shear Strength (Parameter Borehole: TAUFAIL)

Conference ·
OSTI ID:21326045
; ; ;  [1]
  1. Sandia National Laboratories, Carlsbad, NM (United States)
The Waste Isolation Pilot Plant demonstrates compliance with federal containment requirements by means of performance assessment calculations carried out to estimate the probability and consequences of radionuclide releases from the repository to the accessible environment. These calculations are performed using a system of computer codes which assess twenty-four peer-reviewed conceptual models. One of those is the cuttings and cavings model, which determines the amount of waste material that would be eroded off a borehole wall due to drilling mud flowing up the borehole during an inadvertent drilling intrusion that intersects the repository. This paper describes the results of several investigations to better constrain the shear strength of the degraded waste material constituting the borehole wall. The lower limit of the range of waste shear strength values is specifically addressed. Based on experimental results on realistic surrogate waste materials, a detailed literature review, and additional analyses it is recommended that the lower value of waste shear strength be changed from 0.05 to 1.50 Pa. In addition to the increase from 0.05 to 1.50 in the lower bound to the range of waste shear strength, a change from log-uniform to a uniform distribution is also recommended for performance assessment calculations. These changes will result in a decrease in the estimated magnitude and frequency of radionuclide releases due to inadvertent human intrusion events. This paper is one of a series of papers describing proposed changes for Waste Isolation Pilot Plant performance assessment calculations as summarized in Nemer et al. (authors)
Research Organization:
WM Symposia, 1628 E. Southern Avenue, Suite 9 - 332, Tempe, AZ 85282 (United States)
OSTI ID:
21326045
Report Number(s):
INIS-US--10-WM-08097
Country of Publication:
United States
Language:
English