Post-test analysis and accuracy quantification of PKL Test E2.2 by Relap5/Mod3.2 gamma and Relap5-3D

The document deals with the description of results obtained by the Relap5 codes in the post-test’ Of experiment E2.2 performed in the Pressurized Water Reactor (PWR) experimental simulator PKL installed at the Erlangen AREVA Research Center in Germany. The Relap5 (both the current USNRC and INL versions) are the well-known computer code developed by United States Nuclear Regulatory Commission and by Idaho National Laboratory in US: the code is in use at UNIPI since about three decades. The PKL loop is an Integral Test Facility (ITF) simulating with full height, reduced pressure, full linear power a German 4-loop KWU-Siemens PWR. The PKL has four loops. The concerned test is part of a series of a dozen experiments performed in the framework of an Organization for Economic Cooperation and Development / Nuclear Energy Agency / Committee on the Safety of Nuclear Installations (OECD/NEA/CSNI) project where University of Pisa is special member. The performed experiment deal with boron dilution (diluted boron plugs can be formed in the loop seal of primary system, later on reaching the core and causing the potential of neutron flux excursions and large power peaks - challenging core integrity) and complex Accident Management (AM) situations relevant to improve the AMP (Accident Management Procedures) of existing NPP (Nuclear Power Plants)