Diffusion of xenon in uranium monocarbide

Thesis/Dissertation · Wed Nov 07 04:00:00 EST 1962

DOI:https://doi.org/10.2172/4694056· OSTI ID:4694056

Shaked, Hagai ^[1]

---

1. Univ. of California, Berkeley, CA (United States)

The lattice diffusion coefficient of Xe¹³³ in cast uranium monocarbide was measured in postirradiation anneal experiments in the temperature range 100 to 2000 un. Concent 85% C. It was found that the diffusion coefficient of specimens consisting of large grains (700 to 1000 ) was best approximated by D = (1.17 450 °C in a 0.16)10^-6 exp [-54900 450 °C in a 1200)/ (RT)] in this range. (The units of D are cm²sec, and RT is in units of cal/mole.) Specimens with small grains (20 to 150 microns) exhibited the same diffusion coefficient above 1500 un. Concent 85% C. Below 1500 un. Concent 85% C results with small-grained specimens varied widely, indicating dependence on grain size and, hence, existence of appreciable grain-boundary diffusion. The specimens, which were 5 x 5-mm cylinders, were irradiated in evacuated pyrex capsules, at levels ranging between 6 x 10¹⁴ and 3 x 10¹⁵ n/cm². After irradiation each specimen, contained in a tungsten cup, was annealed isothermally in an induction chamber for about 12 hr. Xe¹³³ released from the annealed specimen was adsorbed on charcoal at liquid nitrogen temperature. The charcoal was monitored continuously with a scintillation detector during the anneal. Total Xe¹³³ content of the specimen was determined by melting the specimen and collecting the Xe on the same charcoal trap. In calculating D the conventional'' analysis, which was applied in previous experiments and in which a uniform concentration of Xe¹³³ at the start of the anneal was assumed, was replaced by a new analysis. In the new analysis, account was taken of the nonuniformity in the concertration of Xe¹³³ at the start of the anneal due to the recoil release during irradiation prior to the anneal. Diffusion coefficients obtained in this experiment were lower by one order of magnitude than those obtained by others for UC particles, and higher by two-and-a-half to three orders of magnitude than those obtained for UC powders. The values of D were of the same order of magnitude as obtained for the diffusion of Xe¹³³ in urania.

• Research Organization: Univ. of California, Berkeley, CA (United States)
• Sponsoring Organization: US Atomic Energy Commission (AEC)
• DOE Contract Number: W-7405-ENG-48
• NSA Number: NSA-17-021670
• OSTI ID: 4694056
• Report Number(s): UCRL--10462
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
ACTIVATED CARBON
ADSORPTION
ANNEALING
CASTING
CRYOGENICS
CYLINDERS
DIFFUSION
GLASS
GRAIN BOUNDARIES
GRAIN SIZE
HIGH TEMPERATURE
IRRADIATION
LATTICES
MEASURED VALUES
MELTING
NUMERICALS
POLYMERS
PYREX
SAMPLING
SCINTILLATION COUNTERS
SEALS
TEMPERATURE
TRAPS
TUNGSTEN
URANIUM CARBIDES
VACUUM
VESSELS
XENON
XENON 133