FISSION-PRODUCT RELEASE FROM "SINGLE-CRYSTAL" UC$sub 2$ PARTICLES

Technical Report · Sat Jun 01 04:00:00 EDT 1963

OSTI ID:4696189

Zumwalt, L R; Gethard, P E; Anderson, E E

The fission-product release of spherical single-crystal UC/sub 2/ particles was studied by means of postirradiation annealing of neutron-activated samples and by exposing samples to a steady rate of photofission, using 30-Mev x rays. The release of the several fission products studied appears to follow the kinetics and temperature-dependence of an activated diffusional process. The anomaious fast release of a portion of the Xe/sup 133/ in annealing experiments may be interpreted as being due to release of attached or trapped xenon atoms by a process not following Fick's law (i.e., by a nondiffusional process). Analysis of the data obtained gives the following diffusion coefficients for krypton, tellurium, iodine, xenon, and barium in UC/sub 2/ (in cm/sec): D/sub Kr/= (6.2 x 10/sup -5) exp (--44,000/RT), D/sub Te/ = (1.26 x 10/sup -5/) exp (-67,000/RT), D/ sub I/ = (4.1 x 10/sup -8/) exp (-53,300/RT), D/sub Xe/ = (4.6 x 10/sup -6/) exp (--68,000/RT), and D/sub Ba/ = (2.0 x 10/sup exp (-49,000/RT). The diffusion coefficient for xenon in UC/sub 2/, expressed by the equation D = D/sub 0/ exp (-- Q/RT), showed remarkable agreement, both as to D/sub 0/ and Q (the activation energy for diffusion), with the diffusion coefficient for xenon in UO/sub 2/ selected by Lustman. A negative activation entropy (--13 eu) for diffusion was found from D/sub 0/. (auth)

• Research Organization: General Atomic Div. General Dynamics Corp., San Diego, Calif.
• DOE Contract Number: AT(04-3)-167
• NSA Number: NSA-17-027784
• OSTI ID: 4696189
• Report Number(s): GA-4267
• Country of Publication: United States
• Language: English

Related Subjects

ACTIVATION ANALYSIS
ANNEALING
BARIUM
DIFFUSION
EQUATIONS
FISSION PRODUCTS
IODINE
IRRADIATION
KRYPTON
MEASURED VALUES
METALS, CERAMICS, AND OTHER MATERIALS
MONOCRYSTALS
NEUTRONS
PHOTOFISSION
REACTION KINETICS
SPHERES
TELLURIUM
TEMPERATURE
URANIUM CARBIDES
X RADIATION
XENON
XENON 133