NID “NUCLEAR INNOVATIVE DESIGN” PROJECT – PROMOTING INNOVATION ON RUPTURE FOR NPP’S FUTURE

Abstract

EDF has been developing and improving reactor technology for decades and is part of the successful EPR project in Taishan which has resulted in a grid connection of a 3rd generation nuclear reactor. Feedback of EPR life stages from design to procurement, building and operating is at the core of the project to increase safety and performance with reduced capital expenditure. EPR is also incorporating recent advances in environmental protection, and technical and economic performance, offering safe, competitively-priced, greenhouse-gas-free production of electricity. Some of those innovations are being developed and promoted in the NID project, Nuclear Innovative Design, a collaborative program between EDF, Framatome and CEA, aiming to investigate the potential of promising advanced options that could be implemented in further versions of the Reactors on EDF portfolio, with a dedicated budget for research activities. This article is a presentation of the main results of the R&D topics. Among other points, five of the most innovative results are summarized even if they were not yet chosen. For instance, we work on systems which require no active controls or operational intervention, as well as for some of them, passive safety systems relying on gravity and natural convection to ensure residual heat extraction during events or accidents. To speed up construction, modular construction could be an option. It’s based on component assembly in a factory environment into structural modules like skids, to be then hoisted into place. Structural modules also include SCS (Steel Concrete Structure) panels, welded together once on site and infilled with lightweight cement composite material. The cost of reinforced concrete is directly linked to the required reinforcement ratio which has been extended to an extreme value for the concrete superstructure, increasing the risk of non-uniformity of the concrete filling. EDF R&D is working on finite element modeling and methods for a more competitive civil nuclear structure design that is still as safe as usual, reducing the amount of steel in reinforced concrete in some configurations while ensuring higher safety performances. Tube bundle densification in steam generators is a way to improve their performance, but unfortunately incurs a wellknown risk of vibration. Experimental studies were performed on the influence of the pitch-to-diameter ratio on two-phase flow-induced forces across a tube bundle. Finally, geopolymers were formulated as alternative paints and tested under accident condition scenarios after being applied on concrete or steel surfaces. Efficient drying and fire resistance are among the expected features. These are some examples of the flourishing innovations conducted in the framework of the NID project by EDF R&D.