THE EFFECT OF NEUTRON IRRADIATION ON BERYLLIUM OXIDE

Technical Report · Mon Oct 01 04:00:00 EDT 1962

OSTI ID:4761876

Hickman, B S

Fast neutron irradiation affects the properties of beryllium oxide by causing displacements and by causing nuclear transmutations. The overall aims of a program to investigate this problem are outlined, information from overseas laboratories is reviewed, and results obtained to date at Lucas Heights are described. Results are given of measurements of properties of beryllium oxide fabricated by various methods and irradiated to doses of up to 7 x 10/sup 20/ nvt (fission neutrons) at temperatures of 75 to 700 deg C. The prcperties include macroexamination, dimensions, porosity, lattice parameter and line broadening, mechanical properties, thermal conductivity, metallography, and long wavelength neutron scattering. It is shown that an anisotropic lattice growth occurs which results in crumbling of the material at high doses. The damage rate is much smaller for irradiation at 500 to 700 deg C than for equivalent doses at 100 deg C. Fine-grained (< 3 mu ) material withstarids crumbling up to much higher doses than coarse-grained material. The relation between macroscopic growth, lattice growth, and the cracking and powdering is discussed in some detail and the results used to show the reasons for apparent discrepancies in data from overseas laboratories. Information relating to the defect structure is discussed, and it is suggested that interstitial clusters in the basal planes are probably the cause of the marked anlsotropy in the lattice growth. The effect of neutron energy spectrum on the damage rate is discussed and finally the potential of beryllium oxideas a reactor material is assessed. It is concluded that very fine grained material should withstand doses of at least 1 to 2 x 10/sup 21/ nvt at temperatures of 500 to 1000 deg C without serious deterioration of properties. More information, particularly on changes of mechanical properties and thermal conductivity, is required to confirm this conclusion and to ascertain whether the material will withstand higher doses. (auth)

• Research Organization: Australia. Atomic Energy Commission Research Establishment, Lucas Heights, New South Wales
• NSA Number: NSA-17-006734
• OSTI ID: 4761876
• Report Number(s): AAEC/E-99
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ANISOTROPY
BERYLLIUM OXIDES
CRACKS
DEFECTS
ELECTRIC CONDUCTIVITY
ENERGY
EXPANSION
FAST NEUTRONS
GRAIN SIZE
HIGH TEMPERATURE
LATTICES
MECHANICAL PROPERTIES
METALS, CERAMICS, AND OTHER MATERIALS
MICROSCOPY
NEUTRON BEAMS
NEUTRONS
POROSITY
RADIATION DOSES
RADIATION EFFECTS
SCATTERING
SPECTRA
TEMPERATURE
THERMAL CONDUCTIVITY