Qualification process of Lobi/mod2 nodalization for Relap5/mod2 code (Steady State Level)

The results obtained in a more-than-a-decade application of thermal-hydraulic system codes to the analysis of experiments performed in Integral Test Facilities (ITF) and Separate Effect test Facilities (SETF) including the participation to several International Standard Problems (ISP) and Standard Problem Exercises (SPE), organized by OECD/NEA/CSNI (Organization for Economic Cooperation and Development / Nuclear Energy Agency / Committee on the Safety of Nuclear Installations) and by IAEA (international Atomic Energy Agency), respectively, suggested the need for new methods and procedures for code application. The words nodalization-qualification, qualitative-accuracy-evaluation, quantitative-accuracy-evaluation, and acceptability-thresholds were introduced. The present document deals with nodalization qualification at the steady state level for the LOBI/mod2 available at the EURATOM JRC of Ispra (Italy): criteria for nodalization development and acceptability thresholds at the ‘steady-state’ level, were fixed and the nodalization of the ITF was developed according to those criteria.