Abstract
Typical Pressurized Water Reactors (PWR) fuel rods are manufactured using zirconium-based alloys as cladding and slightly enriched UO2 sintered pellets as fuel. However, in the last years efforts have been made to develop Accident Tolerant Fuels (ATF) focusing mainly in new materials to replace the cladding in order to avoid the exothermic reaction with steam experienced by zirconium-based alloys under accident conditions as observed during the Fukushima Daiichi accident. In this sense, iron-based alloys appear as a possibility to replace conventional zirconium-based alloys, and the effect of the pellet geometry in the performance of iron-based alloys fuel rods shall be investigated. The fuel pellet geometry experiences changes due to irradiation can promote early gap closure, mechanical loadings to the cladding and/or bamboo effects due to the combination of loads and irradiation creep, and all these effects depend also on the cladding properties. The objective of this paper was to address the influence of geometric parameters in the fuel pellet behavior of a stainless steel fuel rod by means of structural mechanical analysis using the well-known ANSYS software. The parameters evaluated in this paper considered fuel pellet with and without chamfer and dish. The data related to the fuel pellet performance under irradiation were obtained using a modified version of the FRAPCON code considering stainless steel as cladding. Results obtained from mechanical evaluation considering the effects through the responses of the axial, radial, plastic deformations, and resulting tensions were evaluated.
Highlights
Nowadays, efforts to improve the fuel system under accident condition became main stream of research and development in the fuel design area, especially the use of new alloys to overcome some of well-known existing problem with zirconium-based alloys cladding
This work address the fuel pellet geometric design using iron-based alloy as cladding material, stainless steel 348. This material presents better properties compared to zirconium-based alloys, such as high thermal conductivity, and high thermal expansion. Those material properties combined to adequate fuel pellet geometry can improve the fuel system performance under normal and accident condition
The geometry of the UO2 fuel pellet changes in relation to its original shape due to the following main effects: thermal expansion that includes distortions in the original form, formation of cracks, and relocation of pellets fragments; and swelling and densification that is a phenomenon associated with burnup and the effect of restructuring in the pellet
Summary
Efforts to improve the fuel system under accident condition became main stream of research and development in the fuel design area, especially the use of new alloys to overcome some of well-known existing problem with zirconium-based alloys cladding. Under this context, this work address the fuel pellet geometric design using iron-based alloy as cladding material, stainless steel 348. This work address the fuel pellet geometric design using iron-based alloy as cladding material, stainless steel 348 This material presents better properties compared to zirconium-based alloys, such as high thermal conductivity, and high thermal expansion. Relocation can contribute to reduce the gap between the fuel and the cladding
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
