Development of the JSFR fuel handling system and mockup experiments of fuel handling machine in abnormal conditions

To enhance plant economy, the Japan Sodium cooled Fast Reactor (JSFR) aims to simplify a plant system and reduce commodities by adopting innovative technologies. In the JSFR design, a single rotating plug and an upper inner structure (VIS) -with a vertically penetrating slit are proposed, so that the fuel handling machine (FHM) can access any subassembly by horizontal movement of the FHM arm in the slit space. The in-vessel fuel handling system can achieve a compact reactor vessel (RV) to enhance the economic competitiveness. As a result of a full-scale mockup test, excellent performance in normal operation has been shown. Required positioning accuracy and operation speed have been achieved and the position can be controlled under ±1 mm by taken into account elastic deformation of an FHM. In this study, from the viewpoint of achieving reliability of the pantograph type FHM, behavior of the FHM mockup have been investigated under abnormal conditions. Furthermore, malfunction events of the FHM have been identified and measures against them have been shown. (authors)