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| Main Authors: | , , , , |
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| Format: | Preprint |
| Published: |
2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2510.13597 |
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| _version_ | 1866915556099096576 |
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| author | Aguzzi, Fabrizio Armoa, Martín Rabazzi, Santiago M. Pairetti, César Albanesi, Alejandro |
| author_facet | Aguzzi, Fabrizio Armoa, Martín Rabazzi, Santiago M. Pairetti, César Albanesi, Alejandro |
| contents | This work presents a modeling framework to represent the thermomechanical behavior of complex materials based on micromechanical dynamics. The framework is applied to nuclear fuel rod elements composed of Zircaloy-2 cladding tubes and spacer grids under typical Pressurized Water Reactor (PWR) conditions. Thermal expansion and thermal creep are incorporated through a VPSC-FEM coupling with the finite element solver Code_Aster, enabling analysis of in-reactor behavior under combined thermal, mechanical, and irradiation loading. The model captures anisotropic deformation driven by crystallographic texture and prismatic slip activity under radial loading. Thermal creep, being stress-sensitive, contributes to early-stage stress relaxation and strain accumulation, leading to higher strain compared to the irradiation-only case. The interaction of thermal creep with irradiation mechanisms modifies the stress distribution and clearance evolution, with relaxation governed by prismatic slip. For fuel rod components, irradiation-induced mechanisms dominate the long-term clearance behavior, whereas thermal effects remain relevant in contact dynamics during thermal preloading. The stress-strain response is found to be more sensitive to micromechanical processes than to elastic constants. This high-resolution formulation enables predictive modeling of spacer-cladding interaction and provides a foundation for developing reduced-order models. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2510_13597 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Multiphysics Finite Element Modeling of Irradiation and Thermal Behavior Demonstrated on a Fuel-Assembly Problem Aguzzi, Fabrizio Armoa, Martín Rabazzi, Santiago M. Pairetti, César Albanesi, Alejandro Computational Physics This work presents a modeling framework to represent the thermomechanical behavior of complex materials based on micromechanical dynamics. The framework is applied to nuclear fuel rod elements composed of Zircaloy-2 cladding tubes and spacer grids under typical Pressurized Water Reactor (PWR) conditions. Thermal expansion and thermal creep are incorporated through a VPSC-FEM coupling with the finite element solver Code_Aster, enabling analysis of in-reactor behavior under combined thermal, mechanical, and irradiation loading. The model captures anisotropic deformation driven by crystallographic texture and prismatic slip activity under radial loading. Thermal creep, being stress-sensitive, contributes to early-stage stress relaxation and strain accumulation, leading to higher strain compared to the irradiation-only case. The interaction of thermal creep with irradiation mechanisms modifies the stress distribution and clearance evolution, with relaxation governed by prismatic slip. For fuel rod components, irradiation-induced mechanisms dominate the long-term clearance behavior, whereas thermal effects remain relevant in contact dynamics during thermal preloading. The stress-strain response is found to be more sensitive to micromechanical processes than to elastic constants. This high-resolution formulation enables predictive modeling of spacer-cladding interaction and provides a foundation for developing reduced-order models. |
| title | Multiphysics Finite Element Modeling of Irradiation and Thermal Behavior Demonstrated on a Fuel-Assembly Problem |
| topic | Computational Physics |
| url | https://arxiv.org/abs/2510.13597 |