Modeling of Sulfide Inclusion Distributions in Relation to the Environmentally Assisted Cracking of Low-Alloy Steels in a Pressurized Water Reactor Environment

This paper presents results on the effect of a surface treatment on the environmentally assisted corrosion cracking in a pressurized water reactor chemistry. Slow strain rate testing of 316 L austenitic steel with selected rates was performed at pressurized water reactor (PWR) simulated water at 350 °C and in air at 300 °C. Detailed prior and post-testing characterization of two types of surfaces including roughness, hardness, and microstructural analysis was made. Transgranular cleavage-like environmentally assisted cracking (EAC) initiation and growth were observed under PWR conditions. The effect of two surface finishes on the cracking initiation was observed: (i) first crack initiates from the polished surface in a vicinity of the necking area rather than from the ground surface and (ii) then the deeper crack develops in the minimal diameter from the polished surface side than from the ground one.

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A novel test technique for the mechanistic study of initiation of environmentally assisted cracking on a Ni–30Cr–10Fe alloy in simulated pressurized water reactor primary water

Scripta Materialia ◽

10.1016/j.scriptamat.2020.08.016 ◽

2020 ◽

Vol 189 ◽

pp. 122-128

Author(s):

Wenjun Kuang ◽

Han Yue ◽

Xingyu Feng ◽

Bo Yang ◽

Chaowei Guo

Keyword(s):

Mechanistic Study ◽

Pressurized Water Reactor ◽

Pressurized Water ◽

Test Technique ◽

Water Reactor ◽

Environmentally Assisted Cracking ◽

Primary Water

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Pump and Valve Fastener Serviceability in PWR Nuclear Facilities

Journal of Pressure Vessel Technology ◽

10.1115/1.2842160 ◽

1996 ◽

Vol 118 (1) ◽

pp. 38-41

Author(s):

N. T. Moisidis ◽

M. D. Ratiu

Keyword(s):

Boric Acid ◽

Power Plants ◽

Selection Criterion ◽

Low Alloy Steels ◽

Pressurized Water Reactor ◽

Nuclear Facilities ◽

Pressurized Water ◽

Alloy Steels ◽

Borated Water ◽

Maintenance Problem

The results of several studies conducted on corrosion of carbon and low-alloy steels in borated water have shown that impingement of borated steam on ferritic steels or contact with a moist paste of boric acid can lead to high corrosion rates due to high local concentrations of boric acid on the surface. The corrosion process of the flange fasteners of pumps and valves is considered a material compatibility and equipment maintenance problem. Therefore, the nuclear utilities of pressurized water reactor (PWR) power plants can prevent this damage by implementing appropriate fastener steel replacement and extended inspections to detect and correct the cause of leakage. A 3-phase corrosion protection program is presented for implementation based on system operability, outage-related accessibility, and cost of fastener replacement versus maintenance frequency increase. A selection criterion for fastener material is indicated based on service limitation: preloading and metal temperature.

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