V. Papadimitriou, I. Roditis, P. Chatzakos, D. Liaptsis
{"title":"An adaptable and self-calibrating service robotic scanner for ultrasonic inspection of nuclear nozzle-vessel welds","authors":"V. Papadimitriou, I. Roditis, P. Chatzakos, D. Liaptsis","doi":"10.1109/CARPI.2012.6473363","DOIUrl":null,"url":null,"abstract":"In this paper the development of a robotic scanner for non destructive inspection of the nozzle to vessel weld of Boiling Water Reactors (BWR) nuclear power plant reactors is presented. The scanner carries and deploys a specially designed ultrasonic (UT) 2D matrix phased array probe. The 3 degrees of freedom (d.o.f.) robotic scanner is mounted on the nozzle and drives the UT probe over selected areas above the weld on the vessel at predefined paths, via a 2-link manipulator mounted on a carriage, sliding on a precision 360 degrees circular ring. The system is controlled using hybrid position-force control for 3D trajectory tracking. The scanner's novelty lies in the very low setup time needed by operators, but mainly in its self-calibration capability by utilizing a variety of sensors, drastically minimizing the operators' exposure to nuclear radiation. Moreover, it is able to fit on nozzles of various diameters, as well as to operate on non-vertically nozzles welded on the vessel. The UT probe was designed to electronically steer its beam between 35 to 80 degrees and achieve electronic skewing between ±10 degrees for improved detection capabilities of the inspection technique. The developed 2D matrix phased array probe is positioned in a local immersion bath and combined with a flexible membrane front, complying on any curvature variations along the nozzle circumference. The performance of the prototype was successfully validated on a replica of a nuclear power plant nozzle.","PeriodicalId":393732,"journal":{"name":"2012 2nd International Conference on Applied Robotics for the Power Industry (CARPI)","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2012-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"2012 2nd International Conference on Applied Robotics for the Power Industry (CARPI)","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1109/CARPI.2012.6473363","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
In this paper the development of a robotic scanner for non destructive inspection of the nozzle to vessel weld of Boiling Water Reactors (BWR) nuclear power plant reactors is presented. The scanner carries and deploys a specially designed ultrasonic (UT) 2D matrix phased array probe. The 3 degrees of freedom (d.o.f.) robotic scanner is mounted on the nozzle and drives the UT probe over selected areas above the weld on the vessel at predefined paths, via a 2-link manipulator mounted on a carriage, sliding on a precision 360 degrees circular ring. The system is controlled using hybrid position-force control for 3D trajectory tracking. The scanner's novelty lies in the very low setup time needed by operators, but mainly in its self-calibration capability by utilizing a variety of sensors, drastically minimizing the operators' exposure to nuclear radiation. Moreover, it is able to fit on nozzles of various diameters, as well as to operate on non-vertically nozzles welded on the vessel. The UT probe was designed to electronically steer its beam between 35 to 80 degrees and achieve electronic skewing between ±10 degrees for improved detection capabilities of the inspection technique. The developed 2D matrix phased array probe is positioned in a local immersion bath and combined with a flexible membrane front, complying on any curvature variations along the nozzle circumference. The performance of the prototype was successfully validated on a replica of a nuclear power plant nozzle.