Coupled Three-dimensional Neutronic/Thermal-mechanical Analysis of Heat Pipe Cooled Reactor Solid-state Core

The heat pipe cooled reactor solid-state core, which expands at high temperatures, distinguishes the heat pipe cooled reactor from the traditional reactor. This feature introduces the coupling effect of neutronic/thermal-mechanic (N/T-M). The coupled neutronic, thermal-mechanical, and heat pipe heat transfer (N/T-M/HP) strategy was developed. The coupled N/T-M/HP method was applied to the KRUSTY heat pipe cooled reactor. A steady-state normal operating case was simulated to show the redundancy and reliability of the solid-state core. For the normal case, the thermal-mechanical feedback is about -850 pcm from the cold state to the hot state. Analyses show that thermal expansion dominates the inherent safety and self-regulation, and yet threatens the core mechanical safety. Therefore, the mechanical performance of the solid-state core should be carefully analyzed during design and operation.