Intermediate BLOCA scenarios. Sensitivity analysis with TRACE5

Abstract

Many test facilities have produced experimental data on Small Break LOCA (SBLOCA) for code assessment; however, experimental data for Intermediate Break LOCA (IBLOCA) is quite limited. Some experimental examples of research on this range break size can be found in literature [1, 2, 3]. In this work a study of thermalhydraulic code TRACE5 [4, 5], in the frame of OECD/NEA ROSA-2 Project Test 2 (IB-CL-03 in JAEA) [6] has been performed. Test 2 was carried out in the Large Scale Test Facility (LSTF) [7] of the Japan Atomic Energy Agency (JAEA), which simulates a 17% cold leg (diameter 207 mm) IBLOCA in a Pressurized Water Reactor (PWR), Westinghouse type, scaled to 1/48 in volume and two loops. The single-failure of High Pressure Injection (HPI) and Low Pressure Injection (LPI) systems and total failure of Auxiliary Feedwater (AFW) were assumed. It means that HPI and LPI systems only actuate in the intact loop, while the AFW fails in both loops. A detailed TRACE5 model has been developed following these assumptions. Different sensitivity analyses have been performed varying the friction coefficient in the Accumulator Injection System (AIS) and the break size. Furthermore, different TRACE5 versions have been used to simulate this transient.