Reactor core design of UPR-s: A nuclear reactor for silence thermoelectric system NUSTER

Abstract The heat pipe reactor is featured with the passive heat discharge, anti-single point failure and silent operation. Therefore, it could be applied for the power system of underwater vehicles. In this paper, the concept of Unattended Uranium-fueled Portable Reactor (UPR) for the NUclear Silence ThermoElectric Reactor (NUSTER) power system is introduced and the reactor core with a thermal power of 1 MW is neutronics designed. In the core, highly enriched UO2 fuel, sodium heat pipe, molybdenum alloy matrix, beryllium oxide and beryllium reflector are adopted and the reactivity is controlled by four sliding reflectors and four safety rods. In design process, the NECP-MCX code is used to carry out the neutronics calculation. At the same time, the heating unit, core loading, control system and power distribution of the core are described. Furthermore, criticality safety, burnup characteristics, power distribution of the core are specifically analyzed. The results show that the proposed core design meets the requirements of criticality safety and operating life.