Russell NDE Completes a Boiler Tube Inspection Project in New Brunswick
Tuesday, August 2, 2016

Russell NDE Completes a Boiler Tube Inspection Project in New Brunswick

Russell NDE is proud to work all across Canada and use our technology to help clients maintain and detect damage and degradation of their infrastructure. In June, Russell NDE was at the Colson Cove Generating Station (near St. John, NB) on a project for New Brunswick Power.

What Is the Scope of the Project?

Colson Cove Power Generation Station uses bunker-C oil from Venezuela, burning this fuel causes a hard, shiny scale buildup which can be up to 1/4 " thick on the water wall tubes inside the boilers. Russell NDE was hired and sent two skilled technicians to conduct an inspection to detect the presence of any under-scale pitting on the inside of the rifled boiler tubes.

What Technology Did We Use during the Project?

Russell NDE technicians utilized our 16 channel Ferroscope with a contoured E-PIT probe to complete the inspection on this project. The E-PIT probe has 15 channels of detector coils positioned across the crown of the tube and it is adaptable and contoured to closely fit the size of the boiler tube being inspected. The probe examines the hot side of the tube across the crown (within 0.5" from the membrane on either side.) To calibrate, this tool is is scanned across three or four internal, machined flat-bottom holes which simulate the under-scale pitting. We inspected up to 20' of tubes on specific portions of all four water walls. The E-PIT probe is ideally suited to detect wall-loss through thick external scale. It does not need couplant (like ultrasonic probes) and does not need to contact the tube surface (like EMAT probes or MFL or Slofec techniques).

What Is Unique about This Project?

The cause of under-scale pitting is unclear, and it is quite a rare and unusual defect in boiler tubes. Usually the internal rifling inside the tube results in a turbulent flow of the rising hot water which prevents scale from forming. If scale does form, it compromises the tube. Local overheating occurs, and combined with the loss of wall thickness, the tube begins to bulge,and eventually leak. If the under-scale pitting is not detected and repaired, water and steam leakage can occur, leading to a full-scale boiler shutdown.

If a boiler shutdown will severely impact your business, you should ensure that the boiler tubes are monitored and inspected regularly. Russell NDE is an experienced and professional NDE inspection company that can provide this service. Contact us by phone 1 (800) 661-0127 or by e-mail to arrange an inspection.