LBLOCA in CANDU-NG cooled by light water

The purpose of this work is to develop methodologies for the evaluation of LBLOCA in CANDU-NG reactors with the codes DONJON and DRAGON. CANDU-NG reactor differ from traditional CANDU reactors in being cooled by light water, using enriched fuel and burnable poisons, having significantly lesser quantity of heavy water moderator. The evaluation shows that methodology developed for CANDU-NG LBLOCA properly detects positive reactivity introduced in the core by initial voiding in checkerboard pattern, peaking at 143 pcm. Such reactivity quickly becomes negative, however, bottoming at −804 pcm and the reactor shuts down by itself without the intervention of any engineered system.

► Methodology for evaluating LBLOCA with DRAGON and DONJON for publicly available CANDU-NG.
► Proper modelling of checkerboard voiding at beginning of LBLOCA.
► CANDU-NG eventually shuts down by itself, without intervention of any engineered system, in the advent of LBLOCA.