Lead induced stress corrosion cracking of Alloy 690 in high temperature water

Book · Sun Dec 31 04:00:00 EST 1995

OSTI ID:203808

Chung, K K ^[1]; Lim, J K ^[2]; Moriya, Shinichi; Watanabe, Yutaka; Shoji, Tetsuo ^[3]

---

1. Korea Inst. of Nuclear Safety, Taejon (Korea, Republic of)
2. Chonbuk Univ., Chonju (Korea, Republic of). Faculty of Technology
3. Tohoku Univ., Sendai (Japan)

Recent investigations of cracked steam generator tubes at nuclear power plants concluded that lead significantly contributed to cracking the Alloy 600 materials. In order to investigate the stress corrosion cracking (SCC) behavior of Alloy 690, slow strain rate tests (SSRT) and anodic polarization measurements were performed. The SSRTs were conducted in a lead-chloride solution (PbCl{sub 2}) and in a chloride but lead free solution (NaCl) at pH of 3 and 4.5 at 288 C. The anodic polarization measurements were carried out at 30 C using the same solutions as in SSRT. The SSRT results showed that Alloy 690 was susceptible to SCC in both solutions. In the lead chloride solution, cracking had slight dependence on lead concentration and pH. Cracking tend to increase with a higher lead concentration and a lower pH and was mainly intergranular and was to be a few tens to hundreds micrometers in length. In the chloride only solution, cracking was similar to the lead induced SCC. The results of anodic polarization measurement and electron probe micro analysis (EPMA) helped to understand lead induced SCC. Lead was a stronger active corrosive element but had a minor affect on cracking susceptibility of the alloy. While, chloride was quite different from lead effect to SCC. A possible mechanism of lead induced SCC of Alloy 690 was also discussed based on the test results.

• OSTI ID: 203808
• Report Number(s): CONF-950816--; ISBN 1-877914-95-9
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
36 MATERIALS SCIENCE
CHLORIDES
CORROSIVE EFFECTS
CRACK PROPAGATION
EXPERIMENTAL DATA
INCONEL 690
LEAD
LEAD CHLORIDES
PWR TYPE REACTORS
SODIUM CHLORIDES
STEAM GENERATORS
STRESS CORROSION
TUBES