On the Modelling of Leak Rates Through Cracks in Pipes and Tubes

Abstract

A leak rate code, LEAK-RATE Version 1.0, has been developed to predict two-phase critical mass fluxes, exit pressures and pressure profiles for cracks, which forms an integral part of leak-before-break (LBB) analysis of pressurized reactor components such as pipes and headers. The code can also be used to calculate steam generator tube leakages. LEAK-RATE Version 1.0 code uses the homogeneous frozen model (HFM) for determining critical mass flux, with effects of friction accounted for within the crack. The code predictions have been compared with an extensive experimental database, and also benchmarked against other similar international codes. The code predicted the leak rates and exit pressures to within 225% of experimental data, which represents a reasonably good agreement for leak rate predictions. The predicted pressure profiles within the crack agreed well with experimental data and yielded the same trend as the experimental observations.