Evaluation of the moderator temperature coefficient of reactivity in a PWR by means of noise analysis

The neutron and temperature fluctuations of sensors belonging to one string in a 1300 Mw pressurized water reactor (PWR) were selected for evaluating the magnitude of the moderator temperature coefficient of reactivity (MTC). These fluctuations are less affected by subcooled boiling. A model describing the temperature fluctuations inside and outside the core was developed and the bias of the temperature fluctuations due to position corrected. The resulting MTC magnitude was compared with the design-predicted value