SBIR-STTR Award

Quantitative verification of the residual in-situ stress field which creates the containment cage is needed to assess the factor of safety against hydraulic fracturing from the cavity wall. Phase I will establish the feasibility of developing a passive stress gauge, absent of active instrumentation, and capable of recording the residual in-situ stress field immediately following the nuclear device detonation for a duration of a few minutes. The gauge components will be fabricated and extensively tested under simulated test conditions. The gauge will then be assembled and verified as a whole under simulated test conditions. This will lay the basis for a Phase II effort which would consist of building several gauges for deployment in a nuclear test at the Nevada Test Site.

The goal of this effort is to establish the use of computerized tomography as an accurate and reliable alternative method for measuring physical properties of zeolitized tuff. The feasibility of this approach was established in Phase I. The main emphasis of the Phase II effort will consist of establishing procedures for applying the CT scanning technique to routinely evaluate the physical properties of geologic materials encountered at NTS. This will include formulating detailed procedures to accurately account for the gas/water adsorption characteristics of zeolites, determining the effect of sample inhomogeneity on measurements, and the correlation of physical and mechanical test results.