Seismic Analysis and Isolation Strategies for Spent Fuel Dry Storage Cask Systems

This dissertation presents a thorough and insightful investigation into the long-term seismic safety of spent nuclear fuel dry storage casks (DSCs) and their internal fuel components. It underscores the critical need for robust containment of radioactive materials over extended operational periods to prevent damage and mitigate any potential releases. Based on a comprehensive review of existing literature, the study reveals that the global seismic responses of DSCs-such as sliding, rocking, and accelerations-have been extensively examined, while the localized response of fuel assemblies remains insufficiently explored. Since fuel rods, guide tubes, and other internal components significantly influence overall DSC safety, a deeper understanding of these localized behaviors is essential. To address these knowledge gaps, and to complement recent experimental efforts led by the Department of Energy, the dissertation proposes a versatile numerical framework for seismic analysis and response evaluation of DSCs. This framework integrates high-fidelity and simplified models, and a two-step modeling approach, enabling a wide spectrum of analysis objectives while reducing computational costs. The methodology captures both the global response of DSCs and the localized behavior of fuel assemblies, offering a holistic perspective on their seismic performance. Moreover, it achieves a remarkable reduction-exceeding 70\%-in computational expenses without compromising key dynamic features such as peak accelerations and localized stress distributions. Through evaluations under extreme seismic conditions reflecting various site conditions, the structural integrity of fuel assembly components is further confirmed, with responses remaining below yield limits. The dissertation also explores a meta-material-based seismic isolation strategy. By employing a ``meta-foundation" composed of alternating rubber and concrete layers, the research demonstrates the efficiency of frequency band gaps in filtering and attenuating seismic waves. When applied to multi-story structures, this meta-foundation reduces story accelerations and inter-story drifts by up to 95.1\% and 97.9\%, respectively, compared to conventional concrete foundations. In a novel extension of this concept, the dissertation investigates the effectiveness of meta-foundations for DSCs, showing that system accelerations can be diminished by as much as 95.3\% with careful design. This significant decrease in inertial forces also suggests significant reduction in the dynamic response of the fuel assemblies stored within the cask considerably, which must be further investigated in future investigations.

Level thesis:degree_level

Doctorate Degree

Year dc:date.issued

2025

Author dc:creator

• Elshazly, Fady Ahmed Mohamed

Advisor dc:contributor.advisor

• Seylabi, Elnaz ES

Committee members dc:contributor.committeemember

• Ryan, Keri KR
• Pekcan, Gokhan GP
• Moustafa, Mohamed MM
• Hadj-Nacer, Mustafa MH

• Dry storage cask
• Finite element analysis and modeling
• Meta-materials
• Seismic analysis and isolation
• Spent nuclear fuel
• Structural integrity

Language dc:language.iso

en_US, English

Repository record dc:identifier.uri

https://scholarwolf.unr.edu/handle/11714/11462

OAI identifier oai:identifier

oai:scholarwolf.unr.edu:11714/11462