System codes along with necessary nodalizations are valuable tools for thermal hydraulic safety analysis. Qualifying both codes and nodalizations is an essential step prior to their use in any significant engineering study involving code calculations. ENSO offers independent quality assurance assessment for support to plant operation, DBA analysis and licensing calculations based on two different methodologies: the Advanced Qualification Process (AQP) and SCUP. Both methodologies have been developed and tested by our university staff under the auspicious and recognition of the Spanish Regulatory Council (CSN).