Imaging Radioactive Components Inside a CANDU® Reactor Using Gamma Radiation Scanning

Abstract

A gamma radiation scanning system based on a silicon diode sensor has been developed and used to profile the gamma radiation field along the depth of an in-core start-up instrumentation guide tube inside a CANDU reactor undergoing mid-life refurbishment. These measurements image the radioactive components close to the scanning path, and provide confirmatory information on radiation field strength for material selection and reliability analysis of in-core start-up instrumentation. The positions of two irradiated adjuster rods adjacent to the guide tube and parked above the core were identified from features in the radiation profile. The successful gamma radiation profile measurement provides assurance that this technology could be used to image radioactive components inside the reactor core.