Samuel William Glass

Development of a Trans-World Reactor Vessel Examination System

All three regions of Framatome ANP (Intercontrole in France, intelligeNDT in Germany, and Framatome ANP Inc. in the US) perform pressurized water reactor (PWR) vessel examinations however; each region has historically used different technologies to perform this work. A study was performed in 2001 to assess the feasibility of a common reactor vessel examination tool to service world markets. Although the study concluded there would be some necessary differences regarding regional code considerations, a common set of building blocks could be developed as a foundation for a next-generation tool. A plan was formulated to jointly produce a Trans-World reactor vessel examination System (TWS) to support all three markets. Generally the building blocks included a new robot, a phased array ultrasonic test (PAUT) system, and an advanced analysis system. The advanced robot design was substantially completed in 2002 and was developed to support conventional ultrasonic test (UT) methods with the flexibility to change over to PAUT technology after PAUT qualifications are complete. The robot is designed for higher accuracy and faster scan speeds than previous delivery mechanisms and to facilitate in-containment logistics resulting in shorter vessel occupation times (VOT). This paper discusses the collaborative TWS development project.

Inspection of Bottom Mounted Instrumentation (BMI) J-Weld

Reactor Pressure Vessel (RPV) Bottom Mounted Instrumentation (BMI) primary nozzle ultrasonic (UT) inspections have been performed by AREVA for more than 15 years. EPRI demonstrations were performed in 2004 and an RSEM qualification was obtained in 2005, This UT inspection detects and characterizes cracks in the base metal of the penetration and its interface with the weld. A complementary Visual Examination of the weld or an Eddy Current examination may also be performed but these tests are understood to be marginal with a possibility to miss indications or to mistake inclusions or weld voids for in-service cracks and therefore could force an unnecessary repair. Difficulties associated with examination of this area include: • Unpredictable ultrasonic behaviour in the weld material; • Wavy and complex OD weld surface profile; • Restricted accessibility around the weld surface. AREVA’s Non Destructive Examination Technical Center (NETEC), has developed and/or evaluated several techniques to improve surface and volumetric inspection of this weld including: • A TOFD ultrasonic (UT) probe to detect and characterize cracks within the weld metal from the ID surface of the nozzle. • A flexible UT Phased Array probe to accommodate the wavy and complex weld surface, in partnership with CEA, • Reduced surface ET probes and flexible ET multi-coils (in partnership with CEA), for improved surface inspection, • Infrared Photo-Thermal Camera examination of the weld surface. This paper discusses the designs and performances of these specific probes and NDT techniques as applied to the BMI nozzles, J-welds, and other similar components.Copyright

Photothermal NDE of CRD Penetration J-Groove Welds

A programmatic inspection of both old and replacement Reactor Pressure Vessel (RPV) heads is required by US nuclear utilities in response to the observed cracks and in some cases, leaks. Flaws can initiate either in the nozzle pipe, or in the J-Groove weld between the nozzle and the head. Inspection of the J-groove weld surface has historically been performed by eddy current (ET) or die-penetrant (PT) methods (Reference 1). Both approaches require complex robotic delivery mechanisms, are time consuming to perform, and are subject to false positive indications, or missed calls due to the very complex geometry. A new field-deployable photothermal non-destructive examination (NDE) system has been developed that offers distinct advantages over the ET or PT approach. A laser is scanned to heat a short line (∼20mm) on the material surface. Heat propagation perpendicular to the line is tracked with an IR imaging device. By appropriate signal processing, the image can enhance temperature change gradients indicative of cracks or material flaws. The method can be applied from up to 2 meters away from the surface and the detailed surface scans can be an optical scan rather than a complex-motion contacting tool scan of the surface. This paper outlines laboratory performance of the photothermal NDE system, discusses potential advantages over existing technology for RPV head J-groove inspection, and outlines additional developments for full field implementation.Copyright