EPR™ reactor neutron instrumentation

The core safety during operation is linked, in particular, to the respect of criteria related to the heat generated in fuel rods and to the heat exchange between the rods and the coolant. This local power information is linked to the power distribution in the core. In order to evaluate the core power distribution, the EPRTM reactor relies on several types of neutron detectors: - ionization chambers and proportional counters located outside the vessel and used for protection and monitoring - a fixed incore instrumentation based on Cobalt Self Powered Neutron Detectors used for protection and monitoring - a mobile reference incore instrumentation based on Vanadium aeroballs. This document provides a description of this instrumentation and its use in core protection, limitation, monitoring and control functions. In particular, a description of the detectors and the principles of their signal generation is supplied as well as the description of the treatments related to these detectors in the EPRTM reactor I&C systems (including periodical calibration).