Abstract
A range of pyrolytic carbon structures representative of those used as coatings for nuclear fuel particles was irradiated at temperatures between 540° and 1060°C to fast neutron exposures of 1.5 to 2.4 × 10 81 nvt ( E > 0.18 MeV). Changes in linear dimensions, density, and crystallite size were measured. The data show that irradiation-induced dimensional changes in pyrolytic carbons depend sensitively on their structure. At ~1000°C the dimensional changes depend primarily on the degree of preferred orientation with a secondary dependence on the density of the carbon. The changes calculated for the crystallites are independent of the crystallite height, L c , in the range 30 to 145 Å but the changes are less for larger L c values. At ~600°C the dimensional changes depend on the L c , the density, and the degree of preferred orientation. At this temperature the calculated crystallite changes are very sensitive to variations in L c in the range 30 to 200 Å. At all temperatures the irradiation causes the carbons to densify. The irradiation tends to increase the L c value of carbons with initially small L c values and decreases those of carbons with initially high L c values. The observed irradiation-induced changes are discussed in terms of current theories of irradiation damage in carbons and graphite.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call