Post-Dryout Heat Transfer Assessment of Trace

Abstract

Post-dryout heat transfer experiments conducted on six different test facilities have been simulated with TRACE (V5.0P4). The focus of the experimental condition has been on a system pressure P = 70 bars (although not exclusively) and a broad range of mass fluxes down to boiloff conditions (G = 5235 kg/m²s to G = 2 kg/m²s), while utilizing primary data (as opposed to reduced variables). The test sections included single-tube as well as (5×5), (6×6), and (8×8) rodbundle geometries. Aside from a series of transient tests, all experiments were conducted under stabilized post-dryout conditions, thus providing an effective assessment of the wall-to-coolant heat transfer code performance. Also, comparisons with concomitantly measured axial void profiles were included in some cases of boiloff tests. The calculated results indicated significant disparity of the code predictive capability, which would render the development of a faithfully representative error density function challenging, as in the methodology of best-estimate calculations plus uncertainty analysis (BEPU).