MODTURC-CLAS: An Efficient Code for Analyses of Moderator Crrculation in CANDU Reactors

Abstract

This paper presents a new finite-volume computer code, called MODTURC-CLAS, which has been developed for a special class of applications related to the modelling of the flow and heat transfer in the moderator fluid in a CANDU calandria. Important aspects of the mathematical and numerical formulation of this new code are discussed. Some results of validation studies aimed at assessing the code's performance in predicting experimental measurements conducted on a dedicated moderator circulation test facility are also presented. Comparisons between experimental data and prediction are presented far three test cases, one isothermal and two with heat addition. In all three cases, the MODTURC-CLAS simulations reproduced distinctive flow features and achieved high prediction accuracy. The sensitivity of the predictions to mesh size and convergence criteria is also examined. For the class of problem represented by the above simulations, the experience related to the computing speed of MODTURC-CLAS on workstation, midframe, and mainframe computers is summarized.