Improvement of the $\mathrm{BISON U_3Si_2}$ modeling capabilities based on multiscale developments to modeling fission gas behavior

• Published in: Journal of nuclear materials 2021-05, Vol.555 (-)
• Main Authors: Gamble, K. A., Pastore, G., Cooper, M. W. D., Andersson, D. A., Matthews, C., Beeler, B., Aagesen, L. K., Barani, T., Pizzocri, D.
• Format: Article
• Language: English
• Subjects: BISON; fission gas behavior; multiscale modeling; NUCLEAR FUEL CYCLE AND FUEL MATERIALS; U3Si2; validation
• ISSN: 0022-3115; 1873-4820

Uranium silicide (U3Si2) is a concept explored as a potential alternative to UO2 fuel used in light water reactors (LWRs) since it may improve accident tolerance and economics due to its higher thermal conductivity and increased uranium density. U3Si2 has been previously used in research reactors in the form of dispersion fuel, but operated at lower temperatures than commercial LWRs. The research reactor data illustrated that significant gaseous swelling occurs as the fuel burnup increases. Therefore, it is imperative to understand the fission gas behavior of U3Si2 under higher temperature LWR operating conditions. In this work, molecular dynamics and phase-field modeling techniques are used to reduce the uncertainty in select modeling assumptions made in developing the fission gas behavior model for U3Si2 in the BISON fuel performance code. These lower length scale informed models are then utilized in the validation of BISON U3Si2 modeling capabilities to simulate the ATF-1 experiments irradiated in the Advanced Test Reactor (ATR). Sensitivity analysis (SA) and uncertainty quantification (UQ) are included as part of the validation process to identify where further experiments and lower length scale modeling would be beneficial. Here, the multiscale modeling approach utilized in this work can be applied to new fuel concepts being explored for both LWRs and advanced reactors (e.g., uranium nitride, uranium carbide).