Effects of gaseous environments in gas-cooled reactors and solar thermal heat exchangers on the creep and creep-rupture properties of heat-resisting metals and alloys. Final report
- 1 February 1977
- report
- Published by Office of Scientific and Technical Information (OSTI)
Abstract
Energy conversion systems employing heat exchangers use closed cycle gas turbines with helium as the working fluid. An important design criterion for heat exchanger and turbine systems is the creep strength of the tubing, blading, and vane materials. The design data for these materials generally has been obtained in air. However, there have been reports of adverse environmental effects of helium on the creep strength and ductility of these materials. Much of the environmental data has been obtained using relatively impure helium from high temperature helium-cooled reactor systems (HTGR's). However, power conversion systems using coal or solar energy as the heat source would use commercially pure helium, not subject to the carbonaceous gases that are picked up when helium is used as the coolant for the HTGR's. Stanford University was asked to summarize the environmental effects of helium on the creep properties of heat exchanger alloys. Also, they were asked to conduct critical experiments under what ought to probably be the worst conditions, based on the literature, to determine the maximum extent of the environmental effect. It was found that the environmental effects reported in the literature are relatively small, not more than a factor of two in rupture timemore » or creep rate, which is within the usual experimental scatter and in heat-to-heat variations. The experimental work reported on a HA188 confirmed this conclusion.« lessKeywords
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