The main objective of a standard or a code is to capitalize the technical feedback of constructions. It is the case of the RCC-MR code (now RCC-MRx) which has integrated the technical results of projects such as PHENIX, SUPERPHENIX, Jules Horowitz Reactor, ITER vacuum vessel. These rules are now planned to be used for new plants and it appears that they have to be updated to meet the needs of Gen IV projects like the ASTRID (Advanced Sodium Technological Reactor for Industrial Demonstration) project or MYRRHA (Multi-purpose hybrid research reactor for high-tech applications) project.
This paper presents the ASTRID project approach to initiate in the earlier stage of the design an evaluation of the rules in order to improve as soon as possible the code. The result of this approach in terms of code modifications and improvement objectives are also presented.