Acceptance Test of Graphite Components in Nuclear Reactor

The HTTR is the first high temperature gas-cooled reactor in Japan. It is a test reactor with thermal power of 30 MW and coolant outlet temperature of 950°C at maximum. To achieve high temperature coolant core internals were made of graphite and carbon materials due to their excellent thermal resistivity. After fabrication of graphite and carbon components at works they were installed in the HTTR, and now it is in the power up testing stage. Concerning the inspection standard of the graphite and carbon components, no domestic standard exists as main components in the nuclear reactor. It is necessary, therefore, to prescribe the inspection standards for the HTTR graphite components. Many research and developments in relation to the inspection standard, e.g. in the research field of nondestructive examination of the graphite material, had been performed, and then the JAERI established the inspection standard. The acceptance test of the graphite and carbon components was carried out based on the inspection standard. This paper prescribes the outline of the established inspection standard.