Volume 17: Technology Innovation to Accelerate Energy Transitions

Radiation Damage Study of T91/Fe-Cr-Si Multimetallic Layered Composite for Generation IV Reactor Deployment Shiddartha Paul, Daniel Schwen, Micheal P. Short, Kasra Momeni

Abstract

Multimetallic layered composites (MMLC) have been explored for their suitability as nuclear fuel cladding in nuclear reactors. We studied the radiation resistance of a new MMLC, i.e., T91(Fe90Cr9Mo1)/Fe-Cr-Si (Fe86Cr12Si1), for nuclear fuel cladding in Generation IV reactors, such as Molten Salt Reactor (MSR). We used a multi-objective optimization (MOO) approach to parameterizing a Modified Embedded Atom Method (MEAM) forcefield with Ziegler-Biersack-Littmark (ZBL) modification that can reproduce the two alloy’s mechanical properties and perform the high energy collision cascade simulations. We performed simulations for a broad range of Primary Knock on Atom (PKA) energies, 10-100keV, at 1000K to investigate the effect of the PKA energy on the radiation damage. We found that the diffusion coefficient follows a linear trend with the radiation dose but inversely relates to PKA energies. The mean squared displacement (MSD) at the thermal spike (TS) phase is independent of the PKA energy and decreases during the ballistic phase of the cascade simulation at higher PKA energy. We revealed structural rearrangement for Fe-Cr, Si-Cr, Cr-Mo, and Mo- Mo neighboring atoms upon reaching a critical radiation dose. Our investigation also shows that the number of defects decreases as the PKA energy increases.

Keywords Multimetallic layered Composite (MMLC), Nuclear Material, Radiation Damage, T91, Cascade Simulation, Molecular dynamics