Comparison of Strains Measured on Spacer Grid and Fuel Rod Caused by External Load

The Korea Atomic Energy Research Institute have been evaluated the integrity and retrievability of fuel for transportation and long-term dry storage of spent nuclear fuel. Spacer grid (SG) is one of the structural parts of the fuel assembly. The SG must be enough strong to protect the fuel rod from external loads issued by earthquake and transportation. To evaluate the integrity of the SG, pendulum type impact tests have been performed. Conventionally, the studies were focused on the behavior of a SG, not the fuel rods. However, the behavior of the fuel rods are also as important as the plates. Therefore, in this study, the pendulum type impact test of the SG was performed. The strain data at the plate of the SG and the fuel rod were obtained and compared. A pendulum impact test was carried out to evaluate integrity of the SG and fuel rod during impact. It seems that rod received only an impact force about average 6% of plate. After buckling it lessens average 2%. It seems that SG absorbed more energy after buckling.