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Abstract

The article deals with some fundamental aspects of the fission energy dispersion in nuclear reactor fuel. The analysis starts from the transmission electron microscope observation of tracks produced by energetic fission fragments in thin foils of UO2 single crystals. On the one hand, these tracks appear on the free surface as explosive material displacements. On the other, the passage of fission fragments in the bulk does not leave visible, continuous traces. Furthermore, irradiated U4O9, which consists of a UO2 lattice hosting a temperature sensitive superstructure of interstitial oxygen, persists after experiencing the near-field action of fission fragment thermal spikes. These seemingly inconsistent phenomena have been explained by showing that a large fraction of the fission fragment electronic losses is converted in strong shock waves whose passage in the solid is too fast for producing atomic displacements, but which can release high energies by unloading on free surfaces. The consequent matter displacements have been shown to have important effects on the structural properties of the nuclear fuel.

Additional information

Authors: RONCHI C, European Commission, Joint Research Centre, Institute for Transuranium Elements, Karlsruhe (DE);WISS T, European Commission, Joint Research Centre, Institute for Transuranium Elements, Karlsruhe (DE)
Bibliographic Reference: An article published in:Journal of Applied Physics, Volume 92, Issue 10, (November 15, 2002) pp. 5837-5848
Availability: This article can be accessed online by subscribers, and can be ordered online by non-subscribers, at: http://dx.doi.org/10.1063/1.1513192
Record Number: 200316040 / Last updated on: 2003-03-13
Category: PUBLICATION
Original language: en
Available languages: en