抄録
The Japan Atomic Energy Research Institute has long been carrying out high-temperature gas-cooled nuclear reactor (HTGR) development, including constructing the High Temperature Engineering Test Reactor (HTTR) . Statistical properties of the uniaxial tensile, bending and compressive strengths of a fine-grained isotropic IG-110 graphite for the HTTR core components have been assessed. The assessment based on the data sources compiled from seven mechanical testing programs leads to the following conclusions. The mean tensile strengths for both axial and radial orientations change within ±7% among seven lots. The anisotropy of tensile strength is practically negligible. Combined data sets for tensile, bending and compressive strengths, each consisting of more than 350 measurements, can reasonably be represented on the whole by normal distributions. A Weibull distribution is not justifiable for any data set. Taking into account the statistical bases established, some requirements are presented for defining specified minimum ultimate tensile and compressive strengths (design minimum strengths) in conjunction with material acceptance tests.
