TY - JOUR
T1 - On the effect of nuclear fission cladding stresses on Zirconium hydride orientation and dislocation strain energy fields via Discrete Dislocation Plasticity and Crystal Plasticity Finite Element modelling
AU - Skamniotis, Christos
AU - Long, Daniel
AU - Balint, Daniel
AU - Wenman, Mark
N1 - Publisher Copyright:
© 2024 The Authors
PY - 2025/2
Y1 - 2025/2
N2 - The diffusion of hydrogen in Zircalloy fuel cladding components and its associated delayed hydride cracking (DHC) mechanism remain a bottleneck in nuclear fission. Through Crystal Plasticity Finite Element (CPFE) analysis at the grain scale (μm) and Discrete Dislocation Plasticity (DDP) at the hydride scale (nm), we explore how cladding stress history influences the dislocation network in a system of hydrides, and in turn, how this can impact hydrogen accumulation and embrittlement. CPFE indicates that high tensile stresses at service temperature can cause severe plasticity at a notch of a cladding component, leading to significant residual compressive stresses on service shutdown. As a result, hydrides evolve in this service scenario under a cyclic tensile-compressive background stress, which is found to enhance the ratchetting of dislocations compared to a typical constant background stress history and to eliminate the concentration of tensile residual hydrostatic stresses at the locations of dissolved hydrides. Since these tensile residual stresses drive the local accumulation of hydrogen during progressive precipitation-dissolution cycles, a key question is posed as to whether and how the sequencing of cladding stress-temperature reversals influences the growth rate of macro-hydride colonies. Simultaneously, we find that a large fraction of the total strain energy of hydrides is associated with the strain energy of dislocations and their interactions, posing the question of whether dislocation networks influence the energetically favourable hydride orientation. Our study provides a foundation for future studies of the DHC mechanism and drives the development of thermodynamically consistent dislocation-based models coupled with irradiation effects.
AB - The diffusion of hydrogen in Zircalloy fuel cladding components and its associated delayed hydride cracking (DHC) mechanism remain a bottleneck in nuclear fission. Through Crystal Plasticity Finite Element (CPFE) analysis at the grain scale (μm) and Discrete Dislocation Plasticity (DDP) at the hydride scale (nm), we explore how cladding stress history influences the dislocation network in a system of hydrides, and in turn, how this can impact hydrogen accumulation and embrittlement. CPFE indicates that high tensile stresses at service temperature can cause severe plasticity at a notch of a cladding component, leading to significant residual compressive stresses on service shutdown. As a result, hydrides evolve in this service scenario under a cyclic tensile-compressive background stress, which is found to enhance the ratchetting of dislocations compared to a typical constant background stress history and to eliminate the concentration of tensile residual hydrostatic stresses at the locations of dissolved hydrides. Since these tensile residual stresses drive the local accumulation of hydrogen during progressive precipitation-dissolution cycles, a key question is posed as to whether and how the sequencing of cladding stress-temperature reversals influences the growth rate of macro-hydride colonies. Simultaneously, we find that a large fraction of the total strain energy of hydrides is associated with the strain energy of dislocations and their interactions, posing the question of whether dislocation networks influence the energetically favourable hydride orientation. Our study provides a foundation for future studies of the DHC mechanism and drives the development of thermodynamically consistent dislocation-based models coupled with irradiation effects.
UR - http://www.scopus.com/inward/record.url?scp=85209544417&partnerID=8YFLogxK
U2 - 10.1016/j.jmps.2024.105924
DO - 10.1016/j.jmps.2024.105924
M3 - Article
SN - 0022-5096
VL - 195
JO - JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
JF - JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
M1 - 105924
ER -