Leak rate models and their thermal interaction with structures for Leak-before-Break applications

The calculation of leak rates through narrow cracks is of prime importance when carrying out a Leak-before-Break assessment. The prediction of leak rate is required to assure that a crack would produce a detectable leak well before it was large enough to cause a large break. There is currently some uncertainty in the prediction of leak rates due to the complexity in the flow path and the effect of phase change in the two phase case. Of prime importance when considering two phase flow through cracks is the evolution of the mixture as it moves through the channel. Due to the small amount of time that the fluid is present in the crack, the fluid is in a state of mechanical and thermal non-equilibrium. A more general model is presented here which makes no assumption about the temperature effects on the flow. The same formulation is used for single and two phase flow, and lamina, turbulent and critical flow can all be modeled.