Helium effects on void formation in 9Cr-1MoVNb and 12Cr-1MoVW irradiated in HFIR

Conference · Wed Jan 01 04:00:00 EST 1986

OSTI ID:5602049

Maziasz, P J; Klueh, R L; Vitek, J M

Up to 2 wt % Ni was added to 9Cr-1MoVNb and 12Cr-1MoVW ferritic steels to increase helium production by transmutation during HFIR irradiation. The various steels were irradiated to approx.39 dpa. Voids were found in all the undoped and nickel-doped steels irradiated at 400/sup 0/C, most of them at 500/sup 0/C, but not in any of them at 300 or 600/sup 0/C. Bubble formation, however, was increased at all temperatures in the nickel-doped steels. Maximum void formation was found at 400/sup 0/C, but swelling remained less than 0.5% even with up to 440 appM He. Irradiation at 300 to 500/sup 0/C caused dissolution of as-tempered M/sub 23/C/sub 6/ precipitates and coarsening of the lath/subgrain structure in the 9-Cr steels, whereas the microstructure generally remained stable in the 12-Cr steels. Irradiation in this temperature range also causd compositional changes in the as-tempered MC phase in all the steels, and produced combinations of fine M/sub 6/C, G, and M/sub 2/X precipitates in various steels. The subgrain boundaries appear to be strong sinks that enhance resistance to void formation. Higher helium production during irradiation appears to shorten the incubation period for void formation. The effects of helium on steady state void swelling behavior, however, remain unknown.

• Research Organization: Oak Ridge National Lab., TN (USA)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5602049
• Report Number(s): CONF-860421-50; ON: DE86011766
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360106* -- Metals & Alloys-- Radiation Effects
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700209 -- Fusion Power Plant Technology-- Component Development & Materials Testing
ALLOYS
BARYON REACTIONS
CHROMIUM ALLOYS
ELEMENTS
ENRICHED URANIUM REACTORS
FLUIDS
GASES
HADRON REACTIONS
HELIUM
HFIR REACTOR
IRRADIATION
IRRADIATION REACTORS
ISOTOPE PRODUCTION REACTORS
MOLYBDENUM ALLOYS
NEUTRON REACTIONS
NIOBIUM ALLOYS
NONMETALS
NUCLEAR REACTIONS
NUCLEON REACTIONS
PHYSICAL RADIATION EFFECTS
RADIATION EFFECTS
RARE GASES
REACTORS
RESEARCH AND TEST REACTORS
RESEARCH REACTORS
TANK TYPE REACTORS
TEST REACTORS
THERMAL REACTORS
VANADIUM ALLOYS
VOIDS
WATER COOLED REACTORS
WATER MODERATED REACTORS