Seismic analysis of PWR-RCC fuel assemblies

The present paper investigates the dynamic behaviour of PWR-RCC fuel assemblies under seismic excitation. A simple vibrational model of the fuel assembly is proposed, which leads to natural frequencies whose spacing agree with experimental data. Available experimental results are reviewed. Impact characteristics of Zircaloy spacer grids are also discussed. It is proposed that their soundness criteria be expressed in terms of impact energy rather than in terms of impact force. The computer code CLASH is briefly described; it is utilized to perform a sensitivity analysis. An example of application is also given.