Thermal Power Calculation in a Research Reactor

Research reactors should incorporate the measurement system for the core power to control and regulate the reactor power. The research reactor modeled in this paper is also equipped with three separate and independent detectors to measure the core power; Neutron Measurement System (NMS), Reactor Gamma Monitoring System (RGMS) and Primary coolant Gamma Monitoring System (PGMS). To calibrate these detectors, the thermal power is used as calibration reference. Therefore, it should be ensured that the thermal power be defined to be fully representative of the core power. The thermal power is calculated based on the thermal balance in the reactor pool where the reactor core and heavy water vessel as the heat source are located. In this paper, the calculation logic for the thermal power is explained in detailed and the precautions for calibration are introduced as well. The equation for the core thermal power has been derived according to measuring parameters such as mass flow rate, and temperatures. In addition, the precautions for calibration such as calibration sequence and pool water effect are clarified as well.