Dynamic analysis of dry storage canister and the spent fuels inside under vertical drop in HTR-PM

Abstract

High-temperature gas cooled reactor pebble-bed modular (HTR-PM) uses a dry storage system based on steel storage canisters to store and transport spent fuels on-site. For the canister, one of the key equipment, it is necessary to verify the reliability of the structural design in extreme events, especially under the accidental drop. Since there are 40,000 fuel elements in a canister, interfacial coupling effect between thin-walled storage canister and pebble bed cannot be ignored under the impact. Here, pebble bed and storage canister are modelled by discrete element model and finite element model, respectively. Using this interfacial coupling model, dynamic interactions between the inner surface of canister and spent fuel elements and inside the pebble bed self were analysed numerically. Interactive forces calculated during impact is well applied to diagnose the failure behaviour of fuel elements. The computation results are validated by the full-scale drop test of HTR-PM spent fuel canister.