The high iron content in stainless steel makes iron a suitable surrogate material. Given the sensitivity of RBS and channeling analysis, the possibility of bubble cluster formation cannot be eliminated, even when SEM and TEM analyses do not provide clear evidence of bubble formation. This fluence level corresponds to a storage period of 107 years, suggesting that there was no significant propagation of possible micro-cracks formed between bubble sites which would allow diffusion of helium within the metal. Therefore, it can be assumed that a storage period of approximately 100 years may not compromise the integrity of stainless steel. However, the impact of increasing lattice disorder resulting from alpha particle irradiation, even in the early years of encapsulation and on areas which may already be stressed, remains unclear.
Conventional calorimeters are large and require longer periods of time to generate accurate results.
The new single gradient heat source calorimeter model is being used to perform a parametric study. In the study, researchers are investigating what effects, if any, the geometry and material properties of insulating endcaps have on the sensitivity and accuracy of heat source measurement. The new model being used in the parametric study assumes an axisymmetric design, with the sample canister positioned in the middle of the calorimeter. The location of the heat source within the sample canister may be varied. The top and bottom layers of insulation are of equal thickness and identical materials.