September-October 2018 NPJ

50 NuclearPlantJournal.com Nuclear Plant Journal, September-October 2018 Robotic Crawler... ( Continued from page 49) means to volumetrically inspect these two line segments. This coupled with EPRI reports discussing the EMAT technique led North Anna to select the EMAT technique to volumetrically inspect the ASW piping in lieu of an excavation. Safety Nuclear safety and Industrial safety were ensured throughout the effort to determine the overall health of the sleeved portions of the ASW line segments. Ensuring the integrity of the ASW lines supports nuclear safety by ensuring that there is an alternative final heat sink source for the station heat load in the event of a design basis accident or plant transient. Industrial safety was championed with the pursuit of 100% volumetric line inspection with a remote operated vehicle in lieu of spot visual inspection. The use of a remote operated vehicle removed the human aspect that has been a challenging part to internal and external inspections of pipes. No longer do station personnel need to be inside the piping for a thorough inspection. This eliminates the potential of injury for personnel while improving the overall quality of inspections by volumetrically examining the piping. Cost-Savings Cost saving impact arises from the comparison of the robotic volumetric inspection of the two ASW lines to a complete excavation of the two ASW lines. A complete excavation to obtain access to the two ASW lines in North Anna’s North yard would cost $2,000,000 – $3,000,000, and a complete excavation would offer only limited access to the two lines since the segments of interest are sleeved. The inspection would also be limited to a visual inspection coupled with random volumetric examination; whereas, the use of Diakont’s EMAT technology permits complete volumetric examination of the pipe wall without having to remove the internal protective coating. Therefore, outer diameter indications, inner diameter indications, and inner wall indications that would possibly be missed by a visual exam and random volumetric inspection would be captured for evaluation. Because of the minimal evasiveness of the EMAT technology, the inspection costs were less than $200,000 for all inspections. Productivity/Efficiency: The project team formation utilized members from all potentially affected organizations plus full engagement of Diakont for the activities. Because the activities had a specific sequence, they were implemented in series with appropriate schedule ties to ensure continuous motion. Dominion Energy and Diakont prepared a scaled down mock-up for testing, and the North Anna team attended the testing at the Diakont San Diego facility. Each ASW line inspection was completed in one day; this minimized impact to the station equipment and station personnel – specifically the station operations department. The inspection rate for these high resolution volumetric inspections averaged 40 feet per hour. Transferability: The key learnings from these inspections are easily transferable to all nuclear plants to ensure full compliance with the Underground Pipe Integrity and Tank initiative. The use of this technology removes the veil of uncertainty in pipe wall integrity by permitting full volumetric inspection of buried piping with the protective coating still remaining in place. The preparation and execution of these inspections provide operating experience for others who have piping arrangements difficult for excavation or wish to eliminate excavations to pursue complete volumetric examinations while minimizing impact on plant resources. Communications: Since completing these inspections, one plant within the United States has contacted NorthAnna to discuss its experiences with this project. Diakont and North Anna Engineering will be presenting our experience utilizing Diakont’s EMAT technology at the 2018 Buried Pipe Information Group (BPIG) meeting. For plants to fully ensure pipe integrity, the addition of this examination technique would minimize some of the uncertainty in pipeline integrity; in tandem, these volumetric inspections provide the much needed data to ensure that cathodic protection systems are effectively arresting the external corrosion on safety-related and safety- significant piping systems. Contact: Chris Allmond, Dominion Energy, telephone: (540) 894-2128, email: christopher.e.allmond@dominionenergy. com. Pipe Inspection Robot with EMAT NDE Sensor Module. Jonny Minder Jonny Minder is the Director of Energy Services for Diakont, and has over a decade of experience in Robotics and NDE within the energy industry. Aaron Huber Aaron Huber is Diakont's Marketing Supervisor and has been overseeing Diakont's global marketing brand since they first opened their doors in the U.S.