3-Dimensional Multiphysics Modeling of Behaviors of Pressurized Water Reactor Fuel Rods With Missing Pellet Surface

Frontiers in Energy Research

Yongjun Deng¹  Zhao Wang²  Wenbo Liu²  Xinhu Zhang³  Yongbo XI³  Di Yun⁴ 

[1] Shenzhen, China;Xi’an, China;Xi’an, China;Chengdu, China;Xi’an, China;Xi’an, China;

关键词: pellet cladding interaction (PCI);    missing pellet surface (MPS);    Stress Corrosion Cracking (SCC);    thermal-mechanical behavior;    nuclear fuels;   

DOI  :  10.3389/fenrg.2021.738084

来源: Frontiers

【 摘 要 】

A 3-dimensional (3D) fuel performance analysis program, able to simulate normal operating conditions and accident conditions for PWR fuel behaviors, was developed based on the Multiphysics Object-Oriented Simulation Environment (MOOSE) finite-element framework. By taking fission products swelling, densification and expansion of pellet, thermal and irradiation creep, gap heat transfer, fission gas release, and cladding crack propagation into consideration, detailed fuel behaviors have been simulated in a multiphysics coupling way. Local defects in fuel pellet caused during manufacturing and filling processes known as the missing pellet surface (MPS) can cause abnormal stress distribution of the cladding and it could even lead to cladding failure. Taking Stress Corrosion Cracking (SCC) phenomenon into consideration, a simulation of PWR fuel rodlet that consists of a pellet with an MPS defect and an intact pellet was conducted. The fuel rod has experienced with sorts of events, including normal operating conditions and a high-power ramp event. The simulation results indicated that: 1) The MPS defect affects the temperature and displacement distribution in the vicinity of the MPS defect. When the pellets are in contact with the cladding, the inner surface of the cladding presents a large tensile hoop stress, which accelerates the crack propagation. 2) During the ramp event, the crack propagation rate was higher than that under normal condition and crack length expanded by about 0.1 µm.

【 授权许可】

CC BY