Comparison of different versions of TRACE5 code in the simulation of LSTF (ROSA V)

The aim of the present work is to describe the main results produced using the thermal-hydraulic code TRACE5, in the frame of OECD/NEA ROSA Project Test 6.1 (SB-PV-9 in JAEA) with the purpose of testing the behavior of the code for this transient. The experiment 6.1 of the OECD/NEA ROSA (SB-PV-9 in JAEA) project was performed in the Large Scale Test Facility (LSTF) of the Japanese Atomic Energy Agency (JAEA). The LSTF simulates a PWR reactor, Westinghouse type, of four loops and 3423 MW of thermal power, scaled to 1/48 in volume and two loops. The experiment simulates an SBLOCA in the upper head of the vessel of a Pressurize Water Reactor (PWR) of four loops. The size of the break is equivalent to 1.9% of the diameter of the cold leg. Three different versions of TRACE5 have been used in the simulation of this transient: TRACE V5.0 RC3 (Release Candidate 3), TRACE V5.0 and TRACE V5.0 patch 01. The same input has been run in each case, obtaining slight differences. The goal of this work is provide a general description of the differences implemented in every version of the code and their effects in the simulation, comparing the results with the experimental ones.