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Conference Article: Non-destructive testing and acceptance test for HTTR graphite components

Takikawa, N.; Iyoku, T.; Shiozawa, S.; Ooka, N. (Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment); Kambe, M.; Ide, A. (Fuji Electric Co. Ltd., Kawasaki, Kanagawa (Japan))

Abstract

The HTTR core is an array of hexagonal graphite blocks. It is supported by graphite core support structures and permanent side reflector blocks. The structural integrity of these graphite components is assured by the detail mechanical design and the acceptance test to guarantee the design. The acceptance test is planned for the graphite components as follows.

1) Material identification tests: To identify the graphite grade of received materials.
2) Impurity tests: To limit impurities to the level specified by the nuclear and shielding designs.
3) Strength tests: To guarantee the strength of received materials.
4) Non-destructive tests: To eliminate components with harmful flaws in them.
To achieve the 4 objectives, ultrasonic and eddy current tests were selected for internal and surface flaw detection, respectively. Preliminary tests were carried out to obtain flaw detectability for the graphite grade used as a material of the HTTR components.

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key words: defects; eddy current testing; graphite; httr reactor; impurities; materials testing; mechanical properties; neutron reflectors; reactor components; supports; testing; ultrasonic testing; acoustic testing; carbon; electromagnetic testing; gas cooled reactors; graphite moderated reactors; helium cooled reactors; htgr type reactors; mechanical structures; nondestructive testing
Reference:
Specialists' meeting on the status of graphite development for gas cooled reactors. Tokai, Ibaraki (Japan). 9-12 Sep 1991
International Atomic Energy Agency, Vienna (Austria)
IAEA-TECDOC--690, pp:281-288