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Effect of a helium environment on the mechanical properties of HTGR primary system metals

Conference ·
OSTI ID:6349347

Creep and high cycle fatigue tests have been carried out on Incoloy 800H and Hastelloy X in a helium environment containing 40 ..mu.. atm of H/sub 2/O, 200 ..mu.. atm H/sub 2/, 40 ..mu.. atm CO, 20 ..mu.. atm CH/sub 4/ and 10 ..mu.. atm CO/sub 2/. The creep behavior of Incoloy 800H does not appear to show significant differences from that measured in air. However, the Hastelloy X at the maximum test temperature studied (871/sup 0/C, 1600/sup 0/F) shows behavior which is inferior. With respect to high cycle fatigue, the Incoloy 800H is weaker in the helium environment at a test temperature of 649/sup 0/C (1200/sup 0/F). At 760/sup 0/C (1400/sup 0/F) the strength in helium is higher but there is a tendency to lose strength more rapidly than for the air tests as the test time increases. Hastelloy X tested at 871/sup 0/C (1600/sup 0/F) also shows higher strength in helium for short test times but for extended tests the strengths in air and helium become similar. Scanning electron microprobe analyses have been carried out to correlate the strength measurements with surface oxidation characteristics and internal structural changes.

Research Organization:
Brookhaven National Lab., Upton, NY (USA)
DOE Contract Number:
EY-76-C-02-0016
OSTI ID:
6349347
Report Number(s):
BNL-NUREG-25326; CONF-781144-15
Country of Publication:
United States
Language:
English