Prompt gamma radiation as a new tool to measure reactor power

•In this paper introduces and validates a new application of neutron capture prompt gamma radiation.•This application of prompt gamma radiation represents a reactor power measurement.•The power measurement has been validated by prompt gamma rays from a HWZPR reactor.•This technique for power measurement can complement and increase redundancy for existing reactor power measurement.•This technique is on-line, prompt.

A new method, based on reactor prompt gamma radiation detection, for reactor power measurement is introduced and validated. To verify, the ex-core gamma radiation spectrum from the Iranian Heavy Water Zero Power Reactor (HWZPR) were measured by HPGe and NaI detectors each suitably positioned. The collective prompt gamma count rates for all or for a portion of each of 2″×2″ NaI detector spectra were obtained for seven power level readings from calibrated reactor power monitors. A good linear behavior was found between gamma count rate and reactor power. The method of calibrated prompt gamma reactor power determination is a stable and reliable tool, on-line, sensitive to sudden variation of power, working in pulse mode, increasing redundancy and diversity and so improving the reactor safety. The prompt gamma counting system can be adopted and installed in other nuclear reactors to measure power.