Design and deployment of weld inspection manipulators for RPV of TAPS-1 and 2

As per regulatory requirements, inspection of welds in RPV is necessary for further continuing operation of TAPS-1 and 2. Upper shell longitudinal welds of RPV which were seen as inaccessible up till now have been inspected first time since operation of the reactors by deploying Weld Inspection Manipulator (WIM) in Unit-1 in August 2012. Subsequently Unit-2 and again Unit-1 upper shell welds were inspected with upgraded versions of WIM in Feb 2013 and March 2015 respectively. Inspection of upper shell welds paves the way for more challenging inspection of beltline region welds. These welds are accessible only from ID surface through a narrow annular gap of 25 mm between RPV wall and thermal shield by managing obstructions due to core internals. A manipulator named as BARC Vessel Inspection System (BARVIS) for inspection of beltline region welds from inner side of the RPV was designed, manufactured, tested and qualified. During Refuelling Outage in January 2016 of Unit -2, BARVIS has been successfully deployed for beltline region welds inspection. Design and deployment of both type of manipulators for upper shell and beltline region welds inspection are discussed in this paper. Data acquisition system and data analysis are not covered in this paper. (author)