The simple chemical rate theory of irradiation damage in graphite is modified to take account of two effects: (a) The mobility of vacancies parallel to the hexagonal axis of the crystal. (b) The thermal annealing of the non-saturable sinks for point defects and the presence of the thermal equilibr
The application of chemical rate theory to fast neutron irradiation damage in graphite
β Scribed by B.T. Kelly
- Publisher
- Elsevier Science
- Year
- 1976
- Tongue
- English
- Weight
- 712 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0008-6223
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β¦ Synopsis
A simple chemical rate theory of irradiation damage in graphite is developed. The equations relate the concentration of various types of lattice defect as a function of irradiation temperature, crystallite size and atomic displacement rate. Numerical values are proposed for the parameters and the predictions of the theory are compared with a range of experimental data on irradiated graphite. It is found that there is good qualitative and sometimes quantitative agreement between theory and experiment. The model is capable of further development applicable to very high temperature irradiation.
π SIMILAR VOLUMES
The changes in dimensions and lattice parameters produced by irradiation in two reactors with very different dose rate have been studied over the temperature range 400-700Β°C. In this range it is found that the activation energy associated with the equivalent temperature concept is not constant. It i
Measurements have been made on the concentrations of vacancies and interstitial clusters in singlecrystal graphite irradiated with neutrons in a reactor and with carbon ions in an accelerator. The irradiations were carried out over a range of temperatures from 30" to 1100Β°C and a range of total init
The characterization of property changes in various grades of near-isotropic, "binderless" grades of graphite as functions of fluence accumulated at 715Β°C from 0 to 42 x 10" neutrons/cm' (E > 50 keV) was made. Generally, the average coefficients of thermal expansion (CTE) from 20 to 600Β°C and the ro
observed etch-patterns seem to have no relation with the dislocation content of the crystals. The imphcations are discussed.
Influence parameters on the irradiation induced change in the Young's modulus investigated for the graphitic matrix for spherical fuel elements are discussed. The irradiation behaviour is compared with that of gilsocarbon graphite.