November 26, 1997    

NKK's Ultrasonic Inspection Pig Makes Record Run on Alaska Pipeline


NKK's ultrasonic pipeline inspection pig on-site in Alaska

NKK's ultrasonic pipeline inspection tool, known as a pig, set a new world record in April 1997 when it successfully completed a continuous inspection of the Trans Alaska crude oil pipeline, covering a distance of 1,055km in one run to check for corrosion in the pipeline.

Running from Prudhoe Bay to the crude oil loading terminal in Valdez,Alaska, the 1,280km-long, 1.2m-diameter Trans Alaska is one of the longest pipelines in the world. Under a contract awarded by Alyeska Pipeline Service Co. in Anchorage, NKK carried out the inspection by dividing the entire length into two sections of 1,055km and 225km, because of the pipeline's structural design. It took a week to inspect the 1,055km section in one run.

NKK's 3.65 meter, 3.2 ton pig can withstand pressures of up to 100 bar.It is equipped with sophisticated sensors, a computer, ultrasonic measuring equipment, a data recorder and other devices. During the Alaska inspection,NKK's pig was propelled through the high-temperature, high-pressure pipeline by liquid flowing at a speed of 7km per hour and collected high-resolution corrosion data along the way. The data collected during the one-week run amounted to 168.8 billion items. The recorded data was then retrieved for processing and analysis to produce a detailed inspection report.

Since commercializing its pipeline inspection service using an ultrasonic pig in the late 1980s, NKK has been widely involved in such operations in Japan and seven overseas countries, gaining an excellent reputation among pipeline operators for its reliable corrosion detection and analysis techniques.To meet the increasing need for cost-effective pipeline maintenance and in view of intensifying global environmental regulations, NKK intends to enhance its marketing efforts for such inspection services.


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