High temperature fast-neutron irradiation of pyrolytic-carbon-coated ThO2 microspheres

✍ Scribed by D.M Hewette II

• Publisher: Elsevier Science
• Year: 1969
• Tongue: English
• Weight: 828 KB
• Volume: 7
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(69)90125-0

✦ Synopsis

We determined the effects of fast-neutron damage aione on four types of pyrolytic-carbon coatings with spherical geometry. The coatings, which ranged in density from 1.75 to 2.0'7 g/cm" and had Bacon anisotropy factors from 1-O to 1.4, were irradiated in the Dounreay Fast Reactor to 4.5 X 102" neutrons/cm2 (> 0.18 MeV) at about 1200°C. A porous buffer layer prevented interaction between the coating and the sol-gel ThO, kernels. Essentially no fissioning occurred in the ThOz in the fast-neutron spectrum. We found that only the coatings with the highest anisotropy factor failed. Coatings with an initial density of 1.8 g/cm3 or less densified while coatings with initial density of 1.9 g/cm3 or greater swelled. Metallographic examination revealed that the preferred orientation increased in the coatings that densified. These changes must be considered in mathematical models describing coated-particle behavior.