Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: Zeke Insepov Project Name: xenon Division: MCS, NE Project title: Multi-scale simulation of radiation damage in nuclear fuels Associated funding: RERTR, AFCI, NEAMS, Argonne LDRD 2013-2015 Other Systems: Blue Gene/aniki Science: Summary of the project: The formation of defects in bcc Mo lattice as a result of 300 keV Xe ion bombardment will be studied via classical atomistic simulation molecular dynamics and kinetic Monte Carlo simulations, with an interatomic potential developed using the force-matching Ab initio based approach. Radiation defect formation via electronic and nuclear stopping power and evolution of the defects in the cascade will be described. Diffusion and interaction of Frenkel pairs, such as self-interstitials, vacancies, and clusters of defects will be analyzed. Stable forms of clusters of defects will be studied that show one-dimensional diffusion with a very high diffusion coefficient and that escape quickly to an open surface. Single vacancies have lower diffusivities and will not aggregate into large clusters. Large prismatic vacancy loop formation near the impact surface will be studied that may be considered as a result of fast recrystallization. The mobility of the vacancy dislocation loop segments will be found, the motion of the entire loops will be studied that strongly hinders the neighbor point defects. A new multiscale concept for irradiated materials simulation will further be developed that will be based on coupling molecular dynamics simulations (MD) where the potential was obtained from Ab initio data of energies of the basic defect structures, with kinetic mesoscale models. The evolution of a system containing self-interstitial atoms (SIAs) and vacancies in crystalline molybdenum will be investigated by means of MD. The kinetics of formation of a dimer clusters (built of two self-interstitial atoms) (di-SIA) and SIA–vacancy recombination will be analyzed via approaches used in the kinetic theory of radiation ageing. The effects of 1D diffusion of SIAs, temperature, and defect concentrations on the reaction rates will also be studied. This approach can validate both the kinetic mechanisms and the appropriate kinetic coefficients, offering the potential to significantly reduce the uncertainty of the kinetic methodology and providing a powerful predictive tool for simulating irradiation behavior of nuclear materials. Project description: The following calculations will be performed for interatomic potentials Mo-Mo, Mo-Xe, U/Mo/Xe in the form of EAM potential: 1. Choosing a structure fitting the potential, calculations of energies and forces on atoms in this configurations from DFT by VASP and potfit codes. 2. Creating the potential by force-matching software PotFit. 3. Verification of the U-Mo-Xe EAM potential obtained by comparison with the DFT data: formation energies of vacancies, self-interstitial atoms (SIA) and their clusters, energies of the basic structures of SIAs, their hierarchy. 4. Verification of the potential with the experimental data on diffusion of defects (diffusion constants, threshold temperatures to induce long-range migration) and production of defects in radiation cascades (structure of the defects and sizes). 5.Improvement of the reference structures to reduce the discrepancies revealed in 3 and 4. computational methods: Density Functional Molecular Dynamics simulations using the siesta method programming model: parallel experiments planned: Argonne IVEM and Atlas experiments, Electron Microscopy software requirements: C++, fortran compiler (e.g. openmpi) sizes of calculations run on and/or planned for LCRC or other systems: hundreds of nano-seconds time scale for classical MD simulations on 1e7-1e8 atomic systems expected number of project members: 7 We expect a total of 7 project members (two from University of Illinois, and several members from the New University of Astana and Russian Academy of Sciences. Results of assessments are expected to lead to joint proposals to NSF, DOE (Office of Science, and NE), and DARPA. Project URL: Current FY Hours Used: undetermined amount New FY Requested allocation: 300000 Q1: 75000 Q2: 75000 Q3: 75000 Q4: 75000 Justification: Thank You, The LCRC Accounts System