Startup transient thermal-hydraulic analysis of a lithium heat pipe cooled reactor Core

Heat pipe cooled reactor has been proposed for applying in the space station and underwater exploration featured with high reliability, low noise level and compact structure. A typical design of a heat pipe cooled reactor system is HP-STMCs designed by the University of New Mexico. It is conceptually designed as a fast reactor, lithiumfilled heat pipes that transfer heat to potassium heat pipes radiator and thermoelectric generators. In this paper, a code is developed for studying the operating thermal-hydraulic characteristics of the reactor core, which consists of core thermal-hydraulic model, neutron kinetics model and heat pipe startup model. The highest temperatures of fuel and matrix in reactor core shows at the 2nd channel, which reach 1720K and 1545K from the results of steady-state. As for the startup transient, the code for heat pipe cooled reactor core successfully predicts key parameters during startup transient, such as each layer material temperature of reactor core, a single heat pipe's temperature response and heat rejection power. The code has initially predicted the transient response of the heat pipe cooled reactor under 800W/s and130W/s power increasing rates. It is discussed that the startup strategy of power increasing rates is based on heat pipe transition temperature (916K). This research provides valuable experience for designing and formulating control strategies of the heat pipe cooled reactor.