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Recent studies have shown that for a variety of unirradiated and irradiated materials, a slope of ∼2 is obtained for a correlation between yield in a shear punch test and yield in a uniaxial tensile test. Application of the von Mises yield criterion would predict a slope of √3. A finite element model (FEM) of the shear punch test was developed to aid in understanding the experimentally obtained slope of ∼2. FEM simulations of the shear punch test were conducted using stress-strain data from uniaxial tensile tests on 316 stainless steel in four initial cold-work conditions. A correlation was developed between the FEM-evaluated effective shear yield strength and the experimentally-evaluated uniaxial yield strength. The slope from this correlation was found to be nearly the same as for the slope from the correlation between the experimentally-evaluated effective shear yield strength and the experimentally-evaluated uniaxial yield strength. The finite element model showed that stresses other than pure shear exist in a specimen during a shear punch test, and these other stresses may explain why the slope of the experimental yield strength correlation is different than √3.

The Office of Civilian Radioactive Waste Management (OCRWM) of the U.S. Department of Energy {DO£) has a mission to provide for the permanent disposal of radioactive wastes in deep geologic repositories. The OCRWM is currently developing a performance assessment strategy for demonstrating compliance with the safety and performance criteria developed by the U.S. Nuclear Regulatory Commission (NRC) and the U.S. Environmental Protection Agency (EPA). Because of the long time (more than 10,000 years) involved, the OCRWM performance assessment strategy necessarily relies upon computerized models of the geologic repository system and its components.

Spalling reduces the lifetime of hot-face refractory linings in slagging coal gasifiers, and has an important impact on the economics of coal gasification. Spalling is caused by ingress of the molten slag into the porous refractory, followed by reaction with the refractory to produce either volumetric expansion (compressive stresses) or volumetric shrinkage (tensile stresses). In this paper, ingress of the molten slag into the porous refractory is described by an effective diffusivity that treats simultaneous capillary and diffusive mechanisms in terms of the average pore radius and the slag viscosity. This effective diffusivity can be applied in spalling models to estimate spall thicknesses that are useful for determining whether the spall originated from tensile or compressive mechanisms.

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