Changes in crystal lattice parameter, c-axis lattice strain and apparent crystallite height induced by neutron irradiation at 72G135O"C were investigated by means of X-ray diffraction for fourteen specimens which included five bands of nuclear graphite and two kinds of pyrolytic graphite. All irrad
171. Effects of changes in irradiation temperature on the irradiation behaviour of graphites and matrix materials
โ Scribed by W.W Delle; M.R Everett; R Blackstone; R Krefeld
- Publisher
- Elsevier Science
- Year
- 1973
- Tongue
- English
- Weight
- 133 KB
- Volume
- 11
- Category
- Article
- ISSN
- 0008-6223
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โฆ Synopsis
part of a joint (Dragon/KFA/Euratom/RCN) irradiation programme in the HFR Petten, The Netherlands, extensive data were obtained on the irradiation behaviour at 8 temperature levels between 400 and 1400ยฐC of 10 different Gilsocarbon graphites. A computer technique was used to systematize and compare the data. It was tried to establish correlations of dimensional changes with initial properties to facilitate extrapolation and prediction. 168. The relation of the dimensional changes of polycrystalline graphites irradiated at 1050ยฐC to their crystal size and structure J. W. Harrison (United Kingdom Atomic Energy Authority, Harwell, England). An attempt has been made to analyze initial crystallite dimensional change rates of a variety of polycrystailine graphites using a combination of macroscopic dimensional change measurements and thermal expansion coefficients at the irradiation temperature. The results obtained are consistent with dimensional change rates reported for pyrolytic graphites of various crystallite sizes. 169. Atomic displacement cross-sections and damage production in graphite* W. C. Morgant (Butte& Pac$ic Northwest Laboratories, Richland, Washington). Recent measurements of the energy required to displace a carbon atom from the graphite lattice, the energy lost from carbon ions by electron excitation and the latest neutron cross-sections, derived from the ENDF/B-III data file for carbon, are combined to derive a new atomic displacement function, which is used for correlating or predicting damage rates in different neutron spectra.
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The characterization of property changes in various grades of near-isotropic, "binderless" grades of graphite as functions of fluence accumulated at 715ยฐC from 0 to 42 x 10" neutrons/cm' (E > 50 keV) was made. Generally, the average coefficients of thermal expansion (CTE) from 20 to 600ยฐC and the ro
observed etch-patterns seem to have no relation with the dislocation content of the crystals. The imphcations are discussed.