Summary and Assessment of Metal Fuel Capabilities in Bison

Abstract

The work described in this report was performed under funding from the Nuclear Energy Advanced Modeling and Simulation (NEAMS) program. This report is issued in satisfaction of the level 2 milestone M2MS-18IN0201012 on Release Bison with Initial Metallic Fuel Performance Capability. Metallic fuel development began in Bison a few years after light water reactor development began (∼ 2009). The initial development was funded by the Advanced Fuels Campaign. With recent interest from industry, the Nuclear Regulatory Commission, and the Versatile Test Reactor program, the Nuclear Energy Modeling Simulation Program has increased funding for metallic fuel development and validation in FY18. The material models with the most mature development are binary uranium-zirconium and ternary uranium-plutonium-zirconium alloys for fuel and HT9 for cladding. The first material models were incorporated from open literature sources, which include mechanical and thermal material properties that are functions of temperature, porosity, and zirconium concentration, swelling, fission gas release, zirconium diffusion, creep, and sodium coolant channel boundary conditions. These material models have been utilized to simulate ERB-II fuel pins and the results compared to measurements. The EBR-II experiment measurements mostly consist of cladding strain and zirconium redistribution. As such, comparisons to EBR-II measurements are currently limited to these two figures of merit. Simulations and comparisons to experiment measurements have also been done for transient testing of EBR-II fuel pins in TREAT, which included temperature measurements. Preliminary comparisons between Bison calculations and experiment measurements are favorable. These comparisons have also highlighted the importance of the fuel swelling and fission gas release models on cladding strain. Also, Bison metallic fuel simulations are currently being run in support of ATR experiments and VTR exploratory design calculations. Further development and evaluation of individual material models and fuel system models are planned for FY19.

BISON: A Flexible Code for Advanced Simulation of the Performance of Multiple Nuclear Fuel Forms

“…120 In recent years, BISON has been updated to account for these phenomena and to provide accurate simulations of zirconium-based metallic fuel in fast reactors. 121 BISON has recently been used to evaluate the fuel performance of annular metallic fuels for an advanced fast reactor concept 122 and is currently being used for fuel design studies for the Versatile Test Reactor. 123 The requisite material models to accurately represent complex metallic fuel behavior are thermal conductivity, heat capacity, thermal expansion, mechanical elasticity, thermal and irradiation creep, solid and gaseous fission product swelling with corresponding porosity generation and interconnection, and zirconium redistribution.…”

BISON: A Flexible Code for Advanced Simulation of the Performance of Multiple Nuclear Fuel Forms [Slides]

“…120 In recent years, BISON has been updated to account for these phenomena and to provide accurate simulations of zirconium-based metallic fuel in fast reactors. 121 BISON has recently been used to evaluate the fuel performance of annular metallic fuels for an advanced fast reactor concept 122 and is currently being used for fuel design studies for the Versatile Test Reactor. 123 The requisite material models to accurately represent complex metallic fuel behavior are thermal conductivity, heat capacity, thermal expansion, mechanical elasticity, thermal and irradiation creep, solid and gaseous fission product swelling with corresponding porosity generation and interconnection, and zirconium redistribution.…”

Fuel Performance Analysis of Fast Flux Test Facility MFF-3 and -5 Fuel Pins Using BISON with Post Irradiation Examination Data

“…Geometric dimensions, initial conditions, boundary conditions, and power and flux histories from each pin from MFF-3 and MFF-5 were supplied from the PNNL reports to be used in conjunction with material models and contact actions within BISON [2,12]. Information within BISON allows for different phenomena-e.g., burnup, porosity, FGR, void swelling, FCCI, and recently U-Pu-Zr hot-pressing-within the simulations to be incorporated into material properties [14,17,18]. This work builds on fully coupled EBR-II simulations previously carried out to incorporate full-length MFF pins similar to the proposed VTR design.…”