Review and Preliminary Investigation into Fuel Loss from Cermets Composed of Uranium Nitride and a Molybdenum-Tungsten Alloy for Nuclear Thermal Propulsion Using Mesoscale Simulations

A ceramic–metal composite (cermet) of uranium nitride (UN) particles embedded in a tungsten-molybdenum (W/Mo) alloy matrix is being considered as reactor fuel for nuclear thermal propulsion (NTP). One possible issue is the loss of fissile uranium atoms during reactor operation. We begin by reviewing...

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Bibliographic Details
Published in:JOM (1989) 2021-11, Vol.73 (11), p.3528-3543
Main Authors: Hirschhorn, Jacob, Hilty, Floyd, Tonks, Michael R., Rosales, Jhonathan
Format: Article
Language:English
Subjects:
Alloys
Atoms & subatomic particles
Cermets
Chemistry/Food Science
Cracks
Earth Sciences
Engineering
Environment
Experiments
Free surfaces
Fuels
Grain boundaries
High temperature
including Space Reactors
Materials for Small Nuclear Reactors and Micro Reactors
Mesoscale phenomena
Molybdenum
Moon
Nitrides
Nuclear fuels
Nuclear reactors
Nuclear thermal propulsion
Particulate composites
Physics
Radiation
Simulation
Space exploration
Tungsten base alloys
Uranium
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Summary:A ceramic–metal composite (cermet) of uranium nitride (UN) particles embedded in a tungsten-molybdenum (W/Mo) alloy matrix is being considered as reactor fuel for nuclear thermal propulsion (NTP). One possible issue is the loss of fissile uranium atoms during reactor operation. We begin by reviewing historical data that suggest that a likely mechanism for fuel loss is transport of free uranium along metal grain boundaries and through cracks to free surfaces. We then employ simple two-dimensional (2D) mesoscale simulations to provide insights into crack formation and free uranium transport in a W/Mo–UN cermet. Phase-field fracture simulations show that cracks form during cooling at the fuel–matrix interface and then within the fuel particles. Transport simulations show that cracks at the fuel–matrix interface and within the fuel accelerate fuel loss. Mechanical and diffusion data are needed for UN and W/Mo alloys to make these preliminary predictions more accurate.
ISSN:1047-4838
1543-1851
DOI:10.1007/s11837-021-04873-x