Structural Design and Analysis of Plate-Type Fuel Assembly of Research Reactor

Abstract Plate-type fuel assembly is widely used in research reactor because of its long-term stable behavior of fuel performance and excellent thermal-mechanical behavior. KJRR (Ki-jang research reactor) fuel assembly adopted plate-type fuel which consists of U-Mo dispersed fuel meat and aluminum matrix. In structural design point of views, fuel structural integrity shall be maintained during the normal operation condition, AOOs (Anticipated operational occurrences) and non-operation conditions, and coolable geometry of fuel assembly shall be maintained during accident such as SSE (safe shutdown earthquake). Structural analyses of KJRR fuel assembly are performed considering the various structural loads expected in the reactor environment. To show that structural damage does not occur due to vibration, a flow-induced vibration test is performed in the simulated reactor loop condition. When the flow velocity is raised to sufficiently high value, fuel plates can be buckled due to unstabilizing hydrodynamic force. The measurement test of critical velocity where the buckling instability begin to occur is performed. This paper presents the structural design criteria of plate-type fuel assembly and summarizes the structural evaluation results.