A Tool for the Prediction of Feeder and Fuelling Machine Interferences Caused by the Elongation of Pressure Tubes in a CANDU Reactor

Abstract

Differences in pressure tube elongation between two adjacent fuel channels in a CANDU reactor could cause problems through feeder to feeder touching or interference with the fuelling machine latching onto a channel during on-power refuelling. The present paper describes an approach to estimate the probabilities of feeder and fuelling machine interferences in the CANDU design. A mathematical model of pressure tube elongation was built, based on the analysis of available pressure tube elongation data. The metallurgical properties of the pressure tubes and the engineering specifications for the installation of these pressure tubes were treated with proper statistical techniques. Finally, the model was implemented by a Monte Carlo computer simulation code called FINSTAN. The model and the computer code FINSTAN can readily be used as the basis for engineering-economic studies of feeder and fuel channel designs of a CANDU power reactor. Application of this technique to Darlington NGS-A design is illustrated.