Integrating ion irradiation and finite element analysis to unravel swelling-induced risks in cr-coated cladding

• Ano de defesa: 2025
• Autor(a) principal: Paixao, Artur Santos
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Texas A&M University
• Palavras-chave em Português: Swelling; Accident-tolerant fuel; Irradiattion creep; Engenharia nuclear; Diretoria-Geral do Desenvolvimento Nuclear e Tecnologia da Marinha (DGDNTM)
• Link de acesso: https://repositorio.marinha.mil.br/handle/ripcmb/848018

Chromium-coated Zircaloy claddings have emerged as a promising accident-tolerant fuel (ATF) design to improve the high-temperature oxidation resistance of nuclear fuel rods, particularly under loss-of-coolant accident (LOCA) scenarios. Chromium’s ability to form a stable, protective oxide layer and its low neutron absorption cross-section make it an attractive candidate for short-term evolutionary ATF solutions. However, under extended operation and irradiation, chromium ex- hibits degradation mechanisms such as interdiffusion with Zircaloy, void swelling, and the forma- tion of brittle intermetallic layers, which can compromise mechanical integrity and nuclear safety margins. This thesis integrates ion irradiation experiments and finite element analysis (FEA) to evaluate the impact of irradiation-induced swelling and creep on the structural performance of Cr- coated claddings. Swelling data from ion-irradiated Cr samples at Accelerator Laboratory Texas A&M are used as input for simulations that assess stress evolution under typical reactor operat- ing and refueling conditions. Results show that swelling significantly increases interfacial stress, while irradiation creep partially offsets this buildup during steady-state operation. However, dur- ing reactor cooldown, when creep is ineffective, the accumulated misfit strains cause sharp tensile stress surges, raising the likelihood of coating delamination and cracking. These findings highlight critical irradiation effects often overlooked in current safety assessments and demonstrate that ig- noring swelling and creep may lead to underpredicted failure risks in ATF designs. The developed methodology can be extended to other coated systems to inform regulatory evaluations and guide safer reactor design.