Document Type : Research Paper

Authors

• Mahdi Abbasi ¹
• mohammadhadi porhemmat ²

¹ Company

² reactor research school, nuclear science and technology research institute

Abstract

From an economic point of view, the increase in nuclear fuel burnup (up to 50 GWd/t ) and the subsequent increase in the length of the reactor cycle is a strong driving force in developing models that include High Burnup Structure (HBS) models in the fuel performance codes. In this research, in order to investigate the behavior of the fission gases for HBS, two semi-empirical models are implemented in the MSFGR-02 code to describe the formation of HBS, which includes the process of polygonization (recrystallization) and release of intra-granular fission gas. For this purpose, by using the grain size measurements (by image processing) provided data in the references in the radial positions where the reconstruction was incomplete, a semi-empirical relationship for the grain radius size and the restructured volumetric fraction as a function of fuel burnup is presented. Finally, the comparison of the changes in the concentration of the fission gas during the irradiation period until reaching HBS with the experimental data presented in the references indicates that the results are in acceptable agreement.

Keywords

• High Fuel Burnup
• Recrystallization
• Fission Gas Release
• Nuclear Fuel Performance