Lessons Learned and Review of Progress in NDT Qualification Projects in Czech Republic
J. Shejbal; Dukovany NPP; L. Horácek, Nuclear Research Institute, Czech Republic
ABSTRACT
A review of international and national projects focused on NDT qualification of inspection procedures, applied equipment and additional personnel qualification in Czech Republic, is given in the paper to highlight the progress and current status of the ISI programme at Dukovany NPP. The following three Phare projects PH 4.1.2/93, PH 1.02/94, PH 1.02/95 completed in the period August 1997 - June 2001, are briefly described with emphasis on their extension and continuation within Czech national NDT qualification projects. The project PH 4.1.2/93 focused on the design and fabrication of the test assemblies representing VVER 440 RPV nozzle safe-end weld, VVER 440 RPV nozzle inner radius, VVER 1000 RPV nozzle inner radius and homogeneous VVER 1000 RPV nozzle to primary piping weld of 850 mm diameter is continued in several Czech national projects oriented on the qualification of mechanised UT inspections of VVER 440 RPV butt welds, cladding and base metal performed from RPV outer and inner surfaces. Within one of the projects an RPV butt weld test assembly, in 1:1 thickness scale, manufactured by original technology using only original materials with more than twenty intended defects was fabricated at the end of 2000. The assumed time schedule of the qualification practical trials for VVER 440 RPV butt welds, dissimilar RPV nozzle safe-end weld and nozzle inner radius inspections is presented. Expected VVER 440 RPV in-service inspection programme changes are described in relation to the NDT qualification projects. The project PH 1.02/94, predominantly devoted to the UT qualification of VVER 440 primary piping austenitic welds, nozzle to pipe welds and dissimilar welds is continued in the frame of a new NRI project where the UT system capability and efficiency should be verified for the VVER 440 SG collector dissimilar weld. The project, assumed to be completed in 2002, will include another test assembly fabrication with additional intended defects and the extension of inspection procedures by scanning from the ferritic side. The project PH 1.02/95 focused on the qualification of mechanised UT and ET inspections of VVER 440 SG collector thread holes is briefly described with the extension by the ET practical trials within the Czech national qualification in spring 2002. Lessons learned from the elaboration of the technical justifications and inspection procedures, optimisation of inspection procedures and laboratory and practical open trials are summarised in the paper. General objectives of the last Phare project PH 1.07/97A, started in January 2001, concentrated on the UT qualification of two inspection areas: longitudinal welds on the VVER 440 main circulation pump elbow and the dissimilar weld under the pressurizer, are briefly outlined.
Publication Source: 3nd International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurized Components, November 14-16, 2001, Seville Spain. Publisher: Tecnatom s.a. - [Homepage]
