NDTsi 2001 Session: Major Component Inspection I-IV
Development and Deployment of a Large-Area Visual Inspection Device for Nuclear Containment Building Inspection
B. Pellegrino, B. Jolley, Everest VIT; P. Lewis, Rochester Gas & Electric, USA
ABSTRACT
The Code of Federal Regulations 10CFR 50.55a requires all commercial nuclear power plants to inspect the entire surface area of the containment building - internally and externally in accordance with ASME Section XI Subsections IWE and IWL. A novel remote visual inspection system has been developed and deployed to allow the viewing and cataloging of thousands of square feet of the steel and concrete surfaces from distances ranging from 55' to over 200' with variable magnification to meet the general, VT-3 and VT-1 ASME Code requirements of subsections IWE and IWL. A general visual examination as required in the ASME code Subsection IWE is an examination that will detect areas of degradation as determined by the utility's RPE (Registered Professional Engineer). At Rochester Gas & Electric's Ginna Station, for example, it was determined that a lower case character size of .174" was the required size needed to detect unacceptable degradation. The lower case character size requirements per ASME Section XI are .105" for a VT-3 and .044 " for a VT-1 examination. For concrete (exterior) inspections ASME Code Subsection IWL is less flexible in that it sets the standard for detection as being the same as that required in IWA-2210 for visual, VT-3 examination. This requires the examiner be able to resolve .105" and .044" character sizes for VT-3 and VT-1 respectively. A semi-automated PC-based system with a mega-pixel digital imaging front-end and 132:1 ratio power zoom lens was developed to allow high-magnification, high-resolution, 4-megabyte image files to be databased for future random access, mapping and comparison.
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]
