The effect of crystal structure stability on the mobility of gas bubbles in intermetallic uranium compounds

Conference · Fri Jan 01 00:00:00 EST 1988

OSTI ID:6529743

Rest, J; Hofman, G L; Birtcher, R C

Irradiation experiments with certain low-enrichment, high-density, uranium-base intermetallic alloys that are candidate reactor fuel materials, such as U/sub 3/Si and U/sub 6/Fe, have revealed extraordinarily large voids at low and medium fuel burnup. This phenomenon of breakaway swelling does not occur in other fuel types, such as U/sub 3/Si/sub 2/ and UAl/sub 3/, where a distribution of relatively small and stable fission gas bubbles forms. In situ transmission electron microscope observations of ion radiation-induced rapid swelling of intermetallic materials are consistent with growth by plastic flow. Large radiation enhancement of plastic flow in amorphous materials has been observed in several independent experiments and is thought to be a general materials phenomenon. The basis for a microscopic theory of fission gas bubble behavior in irradiated amorphous compounds has been formulated. The assumption underlying the overall theory is that the evolution of the porosity from that observed in the crystalline material to that observed in irradiated amorphous U/sub 3/Si as a function of fluence is due to a softening of the irradiated amorphous material. Bubble growth in the low-viscosity material has been approximated by an effective enhanced diffusivity. Mechanisms are included for the radiation-induced softening of the amorphous material, and for a relation between gas atom mobilities and radiation-induced (defect-generated) changes in the material. Results of the analysis indicate that the observed rapid swelling in U/sub 3/Si arises directly from enhanced bubble migration and coalescence due to plastic flow. 34 refs., 11 figs.

• Research Organization: Argonne National Lab., IL (USA)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6529743
• Report Number(s): CONF-880613-28; ON: DE89007417; TRN: 89-006943
• Resource Relation: Conference: 14. international symposium on effects of radiation on materials, Andover, MA, USA, 27 Jun 1988; Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
CRYSTAL STRUCTURE
BUBBLES
THERMAL DIFFUSION
IRON ALLOYS
SILICON ALLOYS
URANIUM BASE ALLOYS
AMORPHOUS STATE
CASCADE THEORY
DISLOCATIONS
FISSION PRODUCTS
G CODES
GRAIN BOUNDARIES
INTERMETALLIC COMPOUNDS
IRRADIATION
MATHEMATICAL MODELS
SWELLING
ACTINIDE ALLOYS
ALLOYS
COMPUTER CODES
CRYSTAL DEFECTS
DIFFUSION
ISOTOPES
LINE DEFECTS
MATERIALS
MICROSTRUCTURE
RADIOACTIVE MATERIALS
URANIUM ALLOYS
050700* - Nuclear Fuels- Fuels Production & Properties
360104 - Metals & Alloys- Physical Properties
360102 - Metals & Alloys- Structure & Phase Studies