Critical analysis of alloy 600 stress corrosion cracking mechanisms in primary water

1995 ◽  
Vol 26 (4) ◽  
pp. 925-939 ◽  
Author(s):  
R. Rios ◽  
T. Magnin ◽  
D. Noel ◽  
O. de Bouvier
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Critical Analysis ◽  
Corrosion Cracking ◽  
Alloy 600 ◽  
Primary Water ◽  
Cracking Mechanisms

Evaluation and Repair of Primary Water Stress Corrosion Cracking in Alloy 600/182 Control Rod Drive Mechanism Nozzles

2002 ◽  
Author(s):  
Charles R. Frye ◽  
Melvin L. Arey ◽  
Michael R. Robinson ◽  
David E. Whitaker
Keyword(s):  
Water Stress ◽  
Boric Acid ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Base Material ◽  
Corrosion Cracking ◽  
Alloy 600 ◽  
Control Rod ◽  
Drive Mechanism ◽  
Primary Water

In February 2001, a routine visual inspection of the reactor vessel head of Oconee Nuclear Station Unit 3 identified boric acid crystals at nine of sixty-nine locations where control rod drive mechanism housings (CRDM nozzles) penetrate the head. The boric acid deposits resulted from primary coolant leaking from cracks in the nozzle attachment weld and from through-thickness cracks in the nozzle wall. A general overview of the inspection and repair process is presented and results of the metallurgical analysis are discussed in more detail. The analysis confirmed that primary water stress corrosion cracking (PWSCC) is the mechanism of failure of both the Alloy 182 weld filler material and the alloy 600 wrought base material.

Stress Corrosion Cracking Incidents and Repair Technologies on PWR Dissimilar Weld Metal Joints in Japan

2010 ◽  
Author(s):  
Naoki Chigusa ◽  
Shinro Hirano ◽  
Takehiko Sera ◽  
Hitoshi Kaguchi ◽  
Masayuki Mukai ◽  
...  
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Power Plants ◽  
Reactor Vessel ◽  
Corrosion Cracking ◽  
Alloy 600 ◽  
Maintenance And Repair ◽  
Head Penetration ◽  
Dissimilar Weld ◽  
Primary Water

Several Japanese PWR power plants have experienced Primary Water Stress Corrosion Cracking (PWSCC) on dissimilar weld joints since 2004. J weld of 3 Reactor Vessel Head Penetration in Ohi unit 3 is one of the PWSCC incidents occurred in 2004 and has been studied by sampling and opening the fracture surface after its repair. Including Ohi unit 3 Reactor Vessel Head Penetration repair, Japanese PWR utilities and MHI have been developing the preventive maintenance and repair technologies applicable to alloy 600 welds and base metal, following PWSCC events on the Bugey-3 and V.C. Summer. This paper describes recent Japanese PWSCC incidents and repair technologies developed in Japan.

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