PART I. IRRADIATION EFFECTS ON BERYLLIUM OXIDE MATERIALS. PART II. IRRADIATION EFFECTS ON DISPERSION TYPE BeO-UO$sub 2$ FUELS FOR EBOR

Technical Report · Tue Oct 01 04:00:00 EDT 1963

OSTI ID:4129569

Simnad, M T

I. The results of irradiation experiments on beryllium oxide materials are presented. The variables studied include the effects of density, grain size, composition, shape, and temperature of irradiation of the specimens. The peak exposure in the irradiation capsule was 1.0 x 10/sup 21/ nvt (>1 Mev) fast neutron flux. The temperature of the specimens ranged from about 260 to 940 deg C. The most striking result was the excellent resistance to cracking exhibited by the high density, fine grain size specimens. The highest strength and strength retention after irradiation was exhibited by the high density, small grain size, 1% MgOcontaining specimens irradiated in the high neutron fluxhigh temperature section of the capsule. Thermal expansion measurements provided a unique means of establishing the annealing behavior of the defects that were produced by irradiation. In beryllium oxide, a contraction set in at 850 deg C. Preliminary results of thermal diffusivity determinations are given. II. Fuel pellets composed of 70 vol% BeO-30 vol% UO/sub 2/ were irradiated. The experiment was designed to study the effect of UO/sub 2/-fuel particle size on the performance of the fuel pellets at temperatures, heat-flux conditions, and burnups that are of interest in the EBOR program. The capsule accumulated 11,700 hours of irradiation in the MTR, corresponding to a peak burnup of about 55% of the U/sup 235/ (approximately 3.7 x 10 fissions per cc, 43,000 Mwd/ton) at a peak fuel temperature of about 2000 deg F. The coarse particle pellets showed little change in dimensions and remained intact. The fine particle pellets fractured into several pieces. The release of fission gases from the fine particle pellets was less than 0.1%. No fission gas release data were obtained for the coarse particle pellets. (auth)

• Research Organization: General Atomic Div., General Dynamics Corp., San Diego, Calif.
• NSA Number: NSA-18-004300
• OSTI ID: 4129569
• Report Number(s): GA-4643; CONF-281-4
• Country of Publication: United States
• Language: English

Related Subjects

ANNEALING
BERYLLIUM OXIDES
BURNUP
CAPSULES
CONFIGURATION
CRACKS
DEFECTS
DENSITY
DIFFUSION
EBOR
EXPANSION
FAST NEUTRONS
FISSION PRODUCTS
FUEL CANS
FUELS
GASES
GRAIN SIZE
HEAT TRANSFER
HIGH TEMPERATURE
MATERIALS TESTING
MEASURED VALUES
METALS, CERAMICS, AND OTHER MATERIALS
NEUTRON FLUX
PELLETS
PERFORMANCE
RADIATION DOSES
RADIATION EFFECTS
REACTORS
STABILITY
TEMPERATURE
TENSILE PROPERTIES
URANIUM 235
URANIUM DIOXIDE
VESSELS