Heat pipes are structures that transport heat by the evaporation and condensation of a working fluid, giving them a high effective thermal conductivity. Many space-based uses for heat pipes have been suggested, and high temperature heat pipes using liquid metals as working fluids are especially attractive for these purposes. These heat pipes are modeled by the THROHPUT code (THROHPUT is an acronym for Thermal Hydraulic Response Of Heat Pipes Under Transients and is pronounced the same as the word ``throughput'').