In-Service Ultrasonic Examination of BWR MC-Nozzles Using Qualified Techniques:Experience in Sweden

Tecnatom has participated in the qualification of some ultrasonic techniques for the Nuclear Power Plants in Sweden. These qualifications have been performed by means of Technical Justifications and practical trials on test specimens with real defects. Also, ultrasonic simulation software has been used as aid for technical justifications. This paper will describe some of these qualification processes and the experiences on-site. The methodology used in these qualifications has allowed an increase in the quality of the inspections, minimization of the operation errors, and knowledge of the reliability of the ultrasonic data and the results reported. This methodology has been extended to the development of inspection techniques for other components (pressure vessel head welds, bottom dome welds), but the process will be presented only for MC-nozzles examination. This paper will also describe the quality procedures and control tools developed, and the advantages obtained by using this methodology.