Predicted thermophysical properties of UN, PuN and (U,Pu)N

Technical Report · Mon Apr 22 04:00:00 EDT 2024

DOI:https://doi.org/10.2172/2377300· OSTI ID:2377300

Galvin, Conor Oscar ^[1]; Navaratnarajah, Kuganathan ^[2]; Barron, Nicholas J. ^[3]; Grimes, Robin W. ^[4]

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1. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Imperial College, London (United Kingdom)
2. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
3. National Nuclear Laboratory Limited, Sellafield (United Kingdom)
4. Imperial College, London (United Kingdom)

Molecular dynamics and density functional theory simulations are used to predict the lattice and electronic contributions of thermophysical properties for UN, PuN, and mixed (U,Pu)N systems. The properties predicted include the lattice parameter, linear thermal expansion, enthalpy, and specific heat capacity, as a function of temperature. The simulation predictions for high temperature specific heat capacity are compared against experimental measurements to understand the behavior, and why differences in the experimental measurements are observed. The influence of adding U vacancies, N interstitials, and Pu to UN is also examined. For this, a new PuN potential parameter set is developed and used with the Kocevski UN potential, enabling the dynamics of mixed (U,Pu)N systems to be studied. How defects impact the thermophysical properties is important for understanding fuel behavior under different reactor conditions, and these mechanistic predictions can be used to support fuel performance codes where data is scarce.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• DOE Contract Number: 89233218CNA000001
• OSTI ID: 2377300
• Report Number(s): LA-UR--23-29300
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS