Codes and methods improvements for safety assessment and LTO: varied approaches

Nuclear safety has always been at the heart of concerns nuclear power plant operators and developers, as well various research organizations regulatory authorities. Over last decades, all these actors have developed integrated a large number calculation codes other tools into their work. From system approach to local understanding phenomenon on given component, from neutronics operation optimization for long-term operation, methods constantly evolving since appearance, in order be able integrate new designs components, improve results modeling physical phenomena or quantify thus reduce uncertainties results. Currently, several H2020 Euratom projects are working improvement methods. This article will focus three projects: CAMIVVER (Codes And Methods Improvements VVER comprehensive assessment), APAL (Advanced PTS Analysis LTO), sCO2-4-NPP (innovative SCO2-based heat removal technology an increased level Power Plants) illustrate our thinking frameworks. First, we present work adopted with regard different used each projects. We then conclude overall analysis approaches, highlighting difficulties successes projects, identifying areas general codes.