HTGR Knowledge Base

Conference Article: Status of design code work for metallic high temperature components

Bieniussa, K. (Gesellschaft fuer Reaktorsicherheit mbH, Koeln (Germany)); Seehafer, H.J. (INTERATOM, Bergisch Gladbach (Germany)); Over, H.H. (Kernforschungsanlage Juelich, IRW, Juelich (Germany)); Hughes, P. (General Electric Co., CA (United States))

Abstract

The mechanical components of high temperature gas-cooled reactors, HTGR, are exposed to temperatures up to about 1000 deg. C and this in a more or less corrosive gas environment. Under these conditions metallic structural materials show a time-dependent structural behavior. Furthermore changes in the structure of the material and loss of material in the surface can result. The structural material of the components will be stressed originating from load-controlled quantities, for example pressure or dead weight, and/or deformation-controlled quantities, for example thermal expansion or temperature distribution, and thus it can suffer rowing permanent strains and deformations and an exhaustion of the material (damage) both followed by failure. To avoid a failure of the components the design requires the consideration of the following structural failure modes: ductile rupture due to short-term loadings. Creep rupture due to long-term loadings. Reep-fatigue failure due to cyclic loadings excessive strains due to incremental deformation or creep ratcheting. Loss of function due to excessive deformations. Loss of stability due to short-term loadings. Loss of stability due to long-term loadings. Environmentally caused material failure (excessive corrosion). Fast fracture due to instable crack growth.

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key words: Gas Cooled Reactor, Nuclear Technology
Reference:
Specialists' meeting on heat exchanging components of gas-cooled reactors Duesseldorf (Germany) 16-19 Apr 1984
International Atomic Energy Agency, International Working Group on Gas-Cooled Reactors, Vienna (Austria)
IWGGCR--9, pp:345-362