Self-initialization of the RELAP4 code momentum equation

One difficulty in using the RELAP4 code is that, owing to the overspecification of the volume and junction input data for the initial conditions, a residual friction term must be defined to establish steady-state conditions. If the corresponding residual friction coefficient is out of allowable range, the calculation is terminated at the initial data checking phase. An allowable residual friction coefficient is added to the form loss coefficient and is used throughout the transient calculation. This might affect the results if the residual friction coefficient is large. However, to model a system represented by a large number of volumes and junctions, manual adjustment of the input data, such as the pressure distribution, to reduce the effect of residual terms can take a significant amount of engineering time. A procedure that allows the code to do the adjustment internally is described