HTGR Knowledge Base

Conference Article: Nondestructive testing of HTGR graphites

Maruyama, T. (Tokyo Inst. of Tech. (Japan). Research Lab. of Nuclear Reactor); Uragaki, H.; Fujii, M.; Ooka, K.; Sakashita, T.; Suzuki, H.; Oku, T

Abstract

This paper describes the results of nondestructive testing of fine-grained, high density, isotropic graphites which are candidate materials to be used in the reactor core of an HTGR. Specimens which containes flaws with various shape and size were fabricated and tested using a pulsed ultrasonic method and an X-ray computed tomography technique. The ultrasonic testing was done using high resolution transducers of longitudinal wave at frequencies 1 and 2.25 MHz. The relationship between ultrasonic echo amplitude and dimension of flaws was obtained. The results was compared with calculated values. The X-ray computed tomography test was done using a commercially available apparatus. Flaws in the graphites were clearly shown and investigation was made to obtain limit of detection of both lamellar and bulk flaws in the nuclear graphites.

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key words: cat scanning; defects; dimensions; graphite; htgr type reactors; reactor cores; shape; size; ultrasonic testing; acoustic testing; carbon; computerized tomography; gas cooled reactors; graphite moderated reactors; materials testing; nondestructive testing; reactor components; tomography
Reference:
Specialists' meeting on graphite component structural design, JAERI Tokai (Japan), September 8-11, 1986
International Atomic Energy Agency, Vienna (Austria). International Working Group on Gas-Cooled Reactors
IWGGCR--11, pp:169-175