A UK analysis of light gas distribution experiment E11.2 in the HDR facility

The HDR facility is a large-scale containment building which is highly compartmentalised except for the upper dome region. The E11.2 experiment in HDR began with a simulated small-break LOCA, followed by a period of light gas injection. The CONTAIN 1.11 code was used in the UK to analyse this test. The predicted pressure history is shown to be in good agreement with the measurements, however, the degree of thermal and compositional stratification within thhe containment was underestimated. Uncertainties in instrument cooler power distribution and difficulty in precisely estimating flowpath resistance coefficients in such a complex geometry can contribute to such discrepancies. In addition, it is shown that much of the discrepancy may arise from the inability to accurately predict certain types of flows within a single physical volume with the kind of engineering flow equations used in the code. (orig.)