Anisotropy in the thermal expansion of uranium silicide measured by neutron diffraction

• In-situ neutron diffraction patterns were collected for a sample of as-cast U3Si2 during heating to 1600 degrees C. Anomalous changes were observed above 1000 degrees C, including the formation of a new diffraction peak not belonging to P4/mbm U3Si2, unequal changes in the peak intensities and onset of anisotropic lattice expansion. The large data-set enabled derivation of a function-fitted isotropic thermal expansion coefficient to high precision, in close agreement with previous dilatometry results but reducing linearly with temperature over the studied interval. Anisotropy in the instantaneous lattice thermal expansion corresponded to anomalies reported by White et al. (2015) at a similar temperature.

Ämnesord

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

Nyckelord

Accident tolerant fuel

In-situ neutron diffraction

Thermal expansion

Uranium silicide

Phase transformation

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