Computational Analysis Of Heat Flow Calorimeters

Heat flow calorimeters are used to determine the mass of nuclear materials within a sealed container by measuring the heat generated by the decay of radioactive isotopes within the sample. This non-destructive assay (NDA) technique can be used with a wide ranger of sample sizes, measuring accurately thermal thermal powers from 0.5 mW to 1000W. Several standard calorimeter designs, such as the twin heat flow calorimeter, are widely used throughout the DOE complex These designs are based on years of experience and laboratory experimentation and have performed well, providing accurate and reliable measurements of thermal power. Computational analyses of the heat and fluid flow within a calorimeter can not be performed to assist in the calorimeter design process, using commercially available CFD (Computational Fluid Dynamics) codes. In particular, parametric studies can be performed to determine efficiently ways to reduce calorimeter size, expense, and operation times. In the present study, a twin heat flow calorimeter is modeled. Computational results are presented showing the effects of varying the calorimeter geometry, component materials, and sample size and positioning within the calorimeter on the accuracy of the thermal power measurements.