Robotics and Manipulators for Reactor Pressure Vessel Head Inspection

摘要

The complex geometry of reactor pressure vessel (RPV) heads presents one of the greatest access challenges for inspection and repair within a typical pressurized water reactor system. Initially most of the Pressurized Water Reactor (PWR) fleet's heads were manufactured with Inconel 600 nozzles and with A-52 weld material that are now known to be susceptible to primary water stress corrosion cracking. Most of these heads have been replaced with less susceptible material but the RPV head component has a demonstrated history of cracks and in some cases significant leaks. This has prompted regulatory mandated periodic inspection and repair if necessary. Subtle differences in the global inspection requirements and in the head geometries also require different inspection tooling for different global regions and designs. AREVA NDE Solutions has been involved in head inspection and repair since the earliest crack indications and has developed an extensive array of robotics and manipulators to address these concerns. This paper describes the main manipulators and inspection tools specifically focusing on recent design evolutions including: 1 NUMAN for under-head inspection and repair tool positioning 2 Advances to ultrasonic blade tools and probes for nozzle and nozzle-weld interface inspection in nozzles with thermal sleeves. 3 Rotating UT and ET tools for nozzles without thermal sleeves 4 An eddy-current J-weld inspection manipulator (recently improved) 5 Clamp-on scanner for EPR nozzle but-welds 6 An eddy-current blade tool with integrated manipulator for AREVA's larger EPR nozzles 7 Head weld seam manipulators for automated head-seam inspection