<p dir="ltr">In the last few decades, the US Department of Energy established the Generation-IV Initiative to advance the design of nuclear energy systems with a focus on fast nuclear reactors. Special interest has been placed on Sodium-cooled Fast Reactors (SFRs) along with metallic fuels. SFRs are attractive because of their ability to utilize fast neutrons effectively, allowing for efficient transmutation of long-lived radioactive isotopes and a more complete use of fissile material. This capability significantly reduces nuclear waste and improves fuel sustainability compared to other Generation IV reactors. The metallic fuels, such as U-Zr and U-Pu-Zr, are attractive because of their higher thermal conductivity and higher density of fissile material, leading to improved breeding ratios and higher burnup rates. Through years of testing, SFRs, such as the EBR-II, could achieve a very high burnup (up to 750 GWD/tU) while traditional generation I to III+ reactors achieve around 30 GWD/tU. Since fast reactors, particularly SFRs, operate on a hard neutron spectrum, they utilize different geometries and cooling materials. This requires the use of different mechanistic models in nuclear codes to accurately capture the underlying physics. The NRC has recently shown interest in upgrading its diffusion codes to support the integration of SFRs. They have shown additional interest in improving the simulation capability of SFR metallic fuel, specifically U-10wt%Zr, even for high fuel burnups in excess of 10 at.%. </p><p dir="ltr">The purpose of this thesis is multifaceted. It serves to develop new mechanistic modelsto support the modeling and analysis of SFRs in existing nodal codes; it also serves to advance the current understanding of the principal effects of U-Zr fuel behavior during steady-state conditions. From the neutronics perspective, a new nodal method will be developed within the PARCS nodal code, along with generalized concepts such as reactivity feedback coefficients and thermal expansion, which will then be validated against the EBRII steady-state benchmark. From the fuel behavior perspective, mechanistic models that describe fuel redistribution, temperature distribution, fission gas, mechanical stresses, and point defect generation will be developed into the Purdue Fuel Performance (PFP) code for U-Zr fuel. The code will then be validated against the radial fuel concentration profile of two EBR-II U-Zr fuel pins.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/26364511 |
| Date | 27 July 2024 |
| Creators | Oscar Lastres (17139529) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/Advanced_Multi-Physics_Simulations_for_Neutronics_and_Fuel_Behavior_in_Sodium-cooled_Fast_Reactors/26364511 |
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