Cathare2v1.5b and Relap5/mod3.3 post test analysis and accuracy quantification of PSB-VVER test PSH-1.4-04 (Test 4 – Primary to Secondary leak)

The document deals with the description of results obtained by the Cathare code in the post-test’ of experiment PSH-1.4-04 performed in the VVER-1000 (Water-cooled, Water-moderated Energy Reactor , 1000 Mwe type) experimental simulator PSB installed at the Elektrogorsk research center in Moscow region (Russia). The experiment is a steam generator tube rupture (also called PRISE = Primary to Secondary leakage) planned to test suitability of Accident Management procedures. The experiment is similar to other experiments performed in LOBI, SPES, BETHSY and LSTF facilities, all of those Pressurized Water Reactor (PWR) experimental simulators. The Cathare is the well-known computer code developed by CEA (Commissariat a l’Energie Atomique) in France in a cooperation with AREVA and EDF: the code is in use at UNIPI since about two decades. The PSB loop is an Integral Test Facility (ITF) simulating with full height, full pressure, full linear power a 4-loop, horizontal Steam Generator, Gidropress VVER-1000. The concerned test is part of a series of a dozen experiments performed in the framework of an European Commission funded research program lead by University of Pisa. The concerned experiment proved the adequacy of the accident management procedures foreseen in VVER-1000. The analysis included the application of the Fast Fourier Transform Based Method (FFTBM) to quantify the accuracy of the code calculation (related to the experimental database).