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Conference Article: The Relationship Between Strength and Modulus In Nuclear Graphite

S.L. Fok, Barry Marsden, The Manchester School of Engineering, University of Manchester, Manchester, UNITED KINGDOM; T.James Marrow, Paul M. Mummery, Manchester Materials Science Centre, University of Manchester, Manchester, UNITED KINGDOM

Abstract

During operation the strength and modulus of HTR graphite components are modified by fast neutron irradiation and oxidation. These two properties are important to the reactor designer as they may govern the life of the graphite components and hence the life of the reactor. It has been traditional to assume that strength changes are the square root of modulus changes. This reasoning is based on the observation of the change in strength of graphite irradiated at low dose and temperature along with the assumption that fracture in graphite can be explained by simple Griffith theory, assuming that the work to fracture and inherent critical flaw size are not modified by irradiation. This paper questions this assumption through the analysis of strength and modulus data for graphite with and without irradiation and/or oxidation, some of which appears to show a linear relationship. An analytical theory which points to an explanation of these experimental observations is given.

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key words: Gas Cooled Reactor, Nuclear Technology
Reference:
Proceedings of the Conference on High Temperature Reactors, Beijing, China, September, 22-24, 2004
International Atomic Energy Agency, Vienna (Austria)
HTR-2004, pp:1-9