Prediction of Reactor Thermal Heat Balance for Improved Mw Output

Abstract

Bulk reactor power is calculated by the Reactor Regulating System (RRS) using thermal measurements from the Fully Instrumented Channels (FINCHs). These measurements are validated against a heat balance calculation which determines reactor power output using secondary side measurements. The difference between them is called the thermal power error. Factors such as fuelling, zone levels, and moderator poison can impact the thermal power error over time. When the thermal power error is positive, RRS is underestimating reactor power and when negative, RRS is overestimating reactor power. These variations are maintained within established operational and safety margins through fuelling and calibration but the optimal balance of safety and economic performance is to have a thermal power error as close as possible to zero in the long term. In this paper, factors influencing the thermal power error are quantified and a method for predicting the behaviour of the thermal power error is presented.