ELECTROSLEEVING APPLICATIONS


11th International Conference on CANDU® Maintenance and Nuclear Components - 2017 Oct. 01-04

Presented at:
11th International Conference on CANDU® Maintenance and Nuclear Components
2017 Oct. 01-04
Location:
Toronto, ON Canada
Session Title:
Component Corrosion and Corrosion Control

Authors:
L. Djordjic (Kinectrics)
G. Palumbo (Integran)
  

Abstract

Different mechanisms of localized corrosion are present in power and process piping at nuclear plants. The inspection, monitoring, and repair of the corrosion affected areas are done during outages, regular or forced, and can be very costly; in certain cases, the unit might be de-rated, or the permanent shutdown of a reactor is required. The conventional repair methods such as mechanically expanded or welded sleeving might be unsuitable as they leave residual stresses, deformation, or alteration of the original material microstructure.
Electrosleeve™ utilizes electrodeposition of a nanocrystalline nickel micro alloy on the internal surface of the piping. It is a non-intrusive and low-temperature process that applies a continuously bonded high strength inner tubular electroform having an average grain size of 100 nm. The electrosleeve provides superior thermal, mechanical, and creep performance with corrosion resistance being comparable to that of high purity nickel. The yield and tensile strength of the nanocrystalline structure is significantly higher than that of conventional wrought alloys, while maintaining good ductility and fracture toughness. The thickness of the plating layer depends on the overall thickness of the piping and regulatory requirements for a repair. Electrosleeve™ is capable of fully restoring the structural integrity of the affected area and rehabilitation of a pressure boundary.
Ontario Hydro's Technologies (OHT) originally developed this technology and it was first applied in 1994, at Ontario Hydro’s Pickering Nuclear Generating Station (PNGS) Unit 5 for a repair of steam generator (SG) tubing. Integran Technologies and Kinectrics are developing this technology to be more universal by applying the same principles on larger diameter piping. The process steps, current density, solution compositions, flow rates, and temperature are optimized for a particular problem. The repair is in-situ, and the NDE inspection is necessary to confirm adhesion and the structural integrity of the layer.

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