Simulation of Fuel-Coolant Interaction SERENA2 Test based on JASMINE Version 3

Abstract

Among twelve FCI cases examined in the OECD / NEA / CSNI / SERENA2 test series using two facilities, six steam explosion cases, five from TROI and one from KROTOS, were analyzed by JASMINE V.3. The major model parameters were categorized into the “focused zone”, i,e., the core part of interest, and the “peripheral zone”, corresponding to the initial and boundary conditions given intentionally for each test case. For the former, base values established through past validation studies of JASMINE V.3 were applied. The code was modified to implement the measured distribution of the entrained droplet size acquired in TROI – VISU. For the latter, melt release histories were given as a combination of time tables of jet diameter and release velocity that were estimated from image data and transit timing data of the melt leading edge. The base values were shown to predict impulse re-sponses of SERENA2 systematically with a reasonable error band. A statistical analysis based on the LHS method was performed. Uncertainty ranges were given on the basis of measurement errors and past validation studies in the development of JASMINE. Underlying mechanisms causing apparent differences in the mechanical energy conversion ratio between two facilities were studied from the viewpoint of breakup length and trigger timing.