Measurement and Simulation of Gamma Radiation Profile inside a CANDU Reactor

Abstract

A gamma radiation profiling system, based on a small, silicon diode, was developed and used to measure the gamma radiation exposure rate within a start-up instrumentation guide tube in a CANDU reactor undergoing refurbishment. The shape of the measured profile agreed with simulations performed using MCNP5; two adjuster rods, located above the core and adjacent to the guide tube, could be clearly identified from the features of the radiation profile measurement and simulation. This technology can be used to accurately measure the positions of irradiated reactor components, such as adjuster rods, and other sources of gamma radiation inside a reactor.