Calculation and Experimental Studies for the Spent Nuclear Fuel Shipping Cask Sealing Assembly
6/22/2023 2023 - #02 Global safety, reliability and diagnostics of nuclear power installations
Gaiazov A.Z. Gaiazov O.Z. Kozlov V.Yu. Pavlov S.V. Samsonov A.A.
https://doi.org/10.26583/npe.2023.2.07
UDC: 621.039.546
One of the safety requirements with respect to the shipping cask for spent nuclear fuel is that its leak-tightness should be maintained by preserving the cask body structural integrity and the sealing system tightness under normal and emergency transportation conditions.
The cask under design has a cylindrical process penetration (port) in its bottom which is sealed using a plug with a radial seal composed of two rubber O-rings. The cask sealing assembly design was justified by the ANSYS LS-DYNA code calculation results. In particular, strains of the cask components were calculated that are caused by the cask drop from a height of 1 m with the cask sealing assembly hitting a vertical bar. The cask was concluded to be leak-tight or leaky based on the strain nature and amount. To verify the adequacy of the results, computer-aided and realistic simulations were undertaken with a 1:2.5-scale mockup cask dropped onto a bar from a height of 1 m. The computational and experimental results show a good agreement in terms of the impact response accelerations (overloads) for the mockup cask and bar collision and in terms of the plastic strains for the key components of the mockup bottom port sealing assembly. This proves the adequacy of the numerical cask model that has been developed and the efficiency of the LS-DYNA simulations. The calculations show that the plastic strains in the cask bottom port region lead to a smaller force of the inner rubber O-ring compression by the port walls, this causing the inner radial seal to lose its tightness. At the same time, the outer seal remains leak-tight ensuring so the mockup cask tightness. The physical test results have also confirmed that the mockup cask remains leak-tight.
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cask leak-tightness tests numerical simulation sealing assembly strain seal
Link for citing the article: Gaiazov A.Z., Gaiazov O.Z., Kozlov V.Yu., Pavlov S.V., Samsonov A.A. Calculation and Experimental Studies for the Spent Nuclear Fuel Shipping Cask Sealing Assembly. Izvestiya vuzov. Yadernaya Energetika. 2023, no. 2, pp. 81-92; DOI: https://doi.org/10.26583/npe.2023.2.07 (in Russian).