Experimental and calculated swelling behavior of U-10 wt.% Mo under low irradiation temperatures.
SEM micrographs of U-10 wt.% Mo irradiated at low temperature in the ATR to about 40 at. % burnup show the presence of cavities. We have used a rate-theory-based model to investigate the nucleation and growth of cavities during low-temperature irradiation of uranium-molybdenum alloys in the presence of irradiation-induced interstitial-loop formation and growth. In addition, the evolution of forest dislocations was calculated based on dislocation loop growth and simultaneous climb and glide of unfaded loops. Consolidation of the dislocation structure takes into account capture of interstitial dislocation loops and annihilation of adjacent dislocations, as well as loss to grain boundaries. A di-interstitial is assumed to be the nucleus of a dislocation loop. Cavities are nucleated when two gas atoms come together in the presence of at least one vacancy. Cavity growth occurs by the influx of gas atoms and/or vacancies. In turn, the free interstitial concentration, and thus (due to recombination) the free-vacancy concentration, depends on the dislocation density. Bias-driven growth of cavities can lead to substantial swelling of the alloy (void swelling). However, our calculations indicate that the swelling mechanism in the U-10 wt.% Mo alloy at low irradiation temperatures is fission gas driven. The calculations also indicate that the observed bubbles must be associated with a sub-grain structure. Calculated swelling and bubble-size-distribution are compared with irradiation data.
- Research Organization:
- Argonne National Lab., IL (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 10983
- Report Number(s):
- ANL/ET/CP-97352; TRN: US0103962
- Resource Relation:
- Conference: 21st International Meeting on Reduced Enrichment for Research & Test Reactors, Sao Paulo (BR), 10/18/1998--10/23/1998; Other Information: PBD: 29 Sep 1998
- Country of Publication:
- United States
- Language:
- English
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