The Development and Use of a Travelling Flux Detector System for Candu Reactors

A portable Travelling Flux Detector (TFD) system has been developed for use on the NRU research reactor at Chalk River, as a first step in developing a TFD system for use on CANDU reactors. The NRU system uses a miniature fission chamber moved by a Babcock and Wilcox drive frame. Results obtained from NRU and from the Bruce Nuclear Generating Station A (NGS A), using a TFD, are presented and discussed. Potential applications of such a system on CANDU power reactors include (i) in-situ calibration of fixed incore detectors, (ii) measurement of creep-sag of fuel channels, (iii) measurement of flux profiles during commissioning, for comparison with physics codes, and (iv) investigation of apparent detector failures and/ or flux anomalies.