Benchmark on Beam Interruptions in an Accelerator-driven System Final Report on Phase I Calculations

This specification is proposed for a computational problem that aims to investigate the outlet core coolant temperature behaviours induced by beam interruptions of varying duration in an XADS-type system. In order to define the common application for the proposed computational benchmark, fuel channel geometry, power data, material properties, heat transfer correlations and the point kinetics are provided. Introduction Transients induced by recovered beam interruptions in a MOX-fuelled and lead-bismuth-cooled, 80 MWth XADS-type system, are proposed as a computational benchmark problem for the comparative assessment of computation methods. The present proposal is made in the frame of a NEA benchmark series for simulation of coupled thermal, fluid dynamics and reactor kinetics transients in accelerator-driven subcritical nuclear reactors. Also this benchmark proposal is designed to have, at least at the present stage, the minimum phenomenological and computational complexity. For this reason, the benchmark specification does not define the detailed geometry, material properties and correlations to investigate fuel or neutronics of an XADS-type system. Nevertheless, the simplifications have been designed to have minimum impact on the main benchmark results, the outlet core coolant temperature trends induced by accelerator beam interruptions having very different durations (1 s, 3 s, 6 s, 12 s and a definitive beam trip). Besides the outlet core coolant temperature, in order to facilitate the result analysis, some few additional results are requested from the benchmark participants.