Analyses of disposal canister falling accidents

    Research output: Book/ReportReport

    Abstract

    This work concerns the evaluation of spent nuclear fuel disposal canister behaviour and integrity in different falling scenarios. The behaviour of the materials that absorb the kinetic energy of the falling disposal canister is also studied. Two different impact scenarios are studied; a canister falling in the canister shaft while it is being lowered towards the spent fuel repository and a canister falling into the deposition hole during installation. If the canister falls while it is being lowered in the shaft it will impact with the shaft shock absorber that is designed to consist of granular lightweight expanded clay aggregate (LECA). If the canister falls while it is being inserted into a deposition hole it will impact with bentonite blocks installed in the hole. Scaled experimental static and dynamic tests have been carried out to determine the behaviour of the LECA shock absorber material under static and dynamic loads. The experimental tests are discussed in this work followed by the numerical modelling of the experiments. The aim of the simulations was to calibrate the models in such a way that they could be applied in simulating full scale canister impact to provide information on the dimensioning of the canister shaft shock absorber and to evaluate the loading subjected to the disposal canister during impact. For evaluating the bentonite behaviour under canister impact, static compression tests and dynamic drop tests were carried out to determine the fracture behaviour of bentonite under dynamic compressive loads. The results of these tests are presented in this work followed by the numerical modelling of the experiments. The aim of simulating these experiments was again to calibrate the models in such a way that they could be applied in simulating a full scale canister impact to bentonite. Based on the studies with both LECA and bentonite as shock absorbing material the most severe load case was identified as an impact with the bentonite blocks. Canister integrity in this load case was evaluated using a detailed finite element model of the canister structure. It was found that the canister is well able to withstand these impact loads.
    Original languageEnglish
    PublisherPosiva
    Number of pages98
    ISBN (Electronic)978-951-652-217-6
    Publication statusPublished - 2012
    MoE publication typeD4 Published development or research report or study

    Publication series

    SeriesPosiva Report
    Number2012-36

    Keywords

    • spent fuel disposal canister
    • falling accident
    • impact
    • experimental studies
    • numerical simulations

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