Space–time convergence analysis on BWR stability using TRACE/PARCS

Multi-physics and multi-scale benchmarking and uncertainty quantification within OECD/NEA framework

“…Axially, the core channels have been divided into 28 axial nodes, with node size proportional to the maximum vapor velocity among all channels (with larger nodes at top of the core) to stay as close as possible to the Courant limit in all cells. As shown in previous stability modeling with TRACE/PARCS (Xu et al, 2009;Gajev et al, 2013), this procedure helps cancel out the spatial and temporal discretization errors as closely as possible in order to minimize numerical diffusion, which has a strong dampening effect on any oscillations predicted by the codes. A finer meshing at the bottom of the core also has the benefit of a well-resolved boiling height, which is important for the prediction of BWR stability.…”

On butterfly effect in the dynamics of Oskarshamn-2 instability event of 1999

“…In recent years, an OECD/NEA Benchmark has been launched in order to analyze a real plant transient (stability event) undergone in the Swedish plant, Oskarshamn-2, on 25th February 1999, during Cycle 24 (Kozlowski, et al, 1999). Among other institutions and universities (Gajev et al, 2013;Kozlowski, 2014;Balestra et al, 2013), the Paul Scherrer Institute (PSI) was an active participant and in this context efforts have been dedicated to study this interesting and challenging stability event (Dokhane et al, 2016;Dokhane et al, 2017). In that context, a stability methodology has been developed and validated, at PSI, based on the three-dimensional reactor kinetics state-of-the-art code SIMULATE-3K (S3K) (Dokhane et al, 2016).…”