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Conference Article: Estimation of graphite materials corrosion with water-vapor in coolant of the VHTR and oxidation effect on the materials properties

Eto, M.; Kurosawa, T.; Imai, H.; Nomura, S.; Oku, T. (Japan Atomic Energy Research Inst., Tokai, Ibaraki. Tokai Research Establishment)

Abstract

Corrosion experiments have been carried out mainly on a fine-grained isotropic graphite, IG-110, at temperatures 1173 and 1473 K in a water vapor/helium mixture. Water vapor concentration was 0.65 vol% and helium pressure, 1 atm. Reaction rate and burn-off profile were measured using cylindrical specimens. On the basis of the experimental data the corrosion behavior of fuel block and core support post under the condition of the VHTR operation was estimated using the first-order or Langmuir-Hinshelwood equation with regard to water vapor concentration. Strength and stress-strain characteristics of the components with burn-off profiles estimated above were analyzed on the basis of the model for stress-strain relationship and strength of the graphite with oxidation gradients. The estimation indicated that the integrity of the components would be maintained during their service lives.

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key words: chemical reaction kinetics; corrosion; graphite; helium; htgr type reactors; isotropy; oxidation; quantity ratio; stress analysis; very high temperature; water vapor; carbon; chemical reactions; gas cooled reactors; gases; graphite moderated reactors
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:189-194