Effects of sulfur chemistry and flow rate on fatigue crack growth rates in LWR environments

Technical Report · Fri Feb 01 00:00:00 EST 1985

OSTI ID:6080529

Cullen, W H; Kemppainen, M; Hanninen, H; Torronen, K

Fatigue crack growth rate tests, at a load ratio of 0.2, have been conducted on steels of low, medium and high sulfur contents (0.004%, 0.013% and 0.025%) in PWR water at both low and high flow rates. Crack growth rates show no dependence on flow rate, but are strongly dependent on sulfur content, with a large proportion of environmental assistance for the highest sulfur contents. Tests of low and high sulfur content steels at a load ratio of 0.7 show relatively little environmental assistance in either case. The fractography of these specimens shows the usual brittle appearance for environmentally-assisted fatigue crack growth. In addition, the opposing fracture surfaces match perfectly, indicating that little or no dissolution of the metal matrix has occurred, and there is very little plastic flow associated with the fatigue cracking process. The x-ray photoelectron emission examination of the fracture surface oxides shows that FeS and FeS/sub 2/ coexist in the oxide layer, suggesting that the conditions within the crack enclave involved near-neutral pH and cathodic potentials.

• Research Organization: Materials Engineering Associates, Inc., Lanham, MD (USA); Valtion Teknillinen Tutkimuskeskus, Espoo (Finland)
• OSTI ID: 6080529
• Report Number(s): NUREG/CR-4121; MEA-2053; ON: TI85901108
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
36 MATERIALS SCIENCE
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CRACK PROPAGATION
FATIGUE
PRESSURE VESSELS
PWR TYPE REACTORS
REACTOR MATERIALS
FRACTURE PROPERTIES
STEEL-ASTM-A533-B
CHEMICAL COMPOSITION
FLOW RATE
SULFUR CONTENT
WATER CHEMISTRY
ALLOYS
CARBON STEELS
CHEMISTRY
CONTAINERS
IRON ALLOYS
IRON BASE ALLOYS
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STEELS
WATER COOLED REACTORS
WATER MODERATED REACTORS
210200* - Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled
360105 - Metals & Alloys- Corrosion & Erosion