HTGR Knowledge Base

Conference Article: Acceptance test for graphite components and construction status of HTTR

Iyoku, T.; Ishihara, M.; Maruyama, S.; Shiozawa, S. (Japan Atomic Energy Research Inst., Ibaraki (Japan)); Tsuji, N.; Miki, T. (Fuji Electric Co. Ltd., Kawasaki, Kanagawa (Japan))

Abstract

In March, 1991, the Japan Atomic Energy Research Institute (JAERI) started to constructed the High Temperature engineering Test Reactor (HTTR) which is a 30-MW(thermal) helium gas-cooled reactor with a core composed of prismatic graphite blocks piled on the core support graphite structures. Two types of graphite materials are used in the HTTR. One is the garde IG-110, isotropic fine grain graphite, another is the grade PGX, medium-to-fine grained molded graphite. These materials were selected on the basis of the appropriate properties required by the HTTR reactor design. Industry-wide standards for an acceptance test of graphite materials used as main components of a nuclear reactor had not been established. The acceptance standard for graphite components of the HTTR, therefore, was drafted by JAERI and reviewed by specialists outside JAERI. The acceptance standard consists of the material testing, non-destructive examination such as the ultrasonic and eddy current testings, dimensional and visual inspections and assembly test. Ultrasonic and eddy current testings are applied to graphite logs to detect an internal flaw and to graphite components to detect a surface flaw, respectively. The assembly test is performed at the works, prior to their installation in the reactor pressure vessel, to examine fabricating precision of each component and alignment of piled-up structures. The graphite components of the HTTR had been tested on the basis of the acceptance standard. It was confirmed that the graphite manufacturing process was well controlled and high quality graphite components were provided to the HTTR. All graphite components except for the fuel graphite blocks are to be installed in the reactor pressure vessel of the HTTR in September 1995. The paper describes the construction status of the HTTR focusing on the graphite components. The acceptance test results are also presented in this paper.

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key words: Gas Cooled Reactor, Nuclear Technology
Reference:
Specialists meeting on graphite moderator lifecycle behaviour. Bath (United Kingdom). 24-27 Sep 1995.
International Atomic Energy Agency, Vienna (Austria)
IAEA-TECDOC--901, pp:239-249