HTGR Knowledge Base

Conference Article: Strength and fatigue properties of near-isotropic graphites

Abstract

Recent research activities at JAERI on the mechanical behavior of graphite for HTR will be reviewed. Several kinds of near-isotropic graphites were used for investigation of their strength and fatigue properties. The research items described here are as follows: (1) the effect of nonlinear stress-strain curve on the bending strength of the petroleum coke graphites. (2) the method for evaluating the ring compressive strength. (3) tensile-tensile and compressive-compressive fatigue strengths of petroleum coke graphites. (4) irradiation effects on the strength of isotropic graphites. Main results obtained here are the following: (1) the effect of non-linear stress-strain curves of the graphite on the bending strength should be taken into account when the bending strength is applied to the safety evaluation of core graphite structures of HTR. (2) an improved equation obtained from the curved beam theory is proposed for evaluating the ring compressive strength. The equation gives more reasonable values of the strength than those proposed by other investigators. (3) the statistical analysis based on the normal distribution was successfully applied to evaluate the fatigue strengths, and (4) the maximum elastic strain energy for the graphite materials under irradiation appeared to be dependent on the irradiation temperature and neutron fluence.

view the full text of this article (7 pages, format: PDF, size= 473kB)

Reference:

Specialists meeting on mechanical behaviour of graphite for HTRs, Gif-sur-Yvette, France, 11-13 June 1979.

International Atomic Energy Agency, Vienna (Austria). International Working Group on High-Temperature Reactors.

IWGHTR--3, pp:96-102