Nuclear NDE

IHI Southwest Technologies has a long history in NDE services for the nuclear industry. IHI is equipped to perform an array of automated and manual NDE services for a variety of nuclear power plant components.

Steam Generator

Due to recent issues concerning primary water stress corrosion cracking (PWSCC) in dissimilar metal welds (DMW) in pressurized water reactors, the American Society of Mechanical Engineers issued Code Case N-770-1, “Alternative Requirements and Acceptance Standards for Class 1 PWR Piping and Vessel Nozzle Butt Welds Fabricated with UNS N06082 or UNS W86182 Weld Filler Material With or Without Application of Listed Mitigation Activities”.

At the time of the issuance, the only approved method for performing Steam Generator (SG) Nozzle DMW was ultrasonic examinations (UT) from the outside surface (OD). Additionally examinations had not been established for the corresponding (S/G) inlet/outlet nozzle-to-reactor coolant piping welds.

As a result, we developed the SG Nozzle Examination Tool (SG-NExT), the first of a kind SG Examination Delivery System that allows the application of a PDI qualified phased array ultrasonic (PAUT) and Eddy Current (ECT) examination that was previously qualified for examination of RPV nozzle DMWs to meet the requirements of examination of DMWs at the SG nozzle from the nozzle interior (ID). The SG-NExT is a remotely operated automated delivery system capable of performing automated PAUT and ECT ID examinations on Alloy 82/182 SG DMWs.

As a result, we developed the SG Nozzle Examination Tool (SG-NExT), the first of a kind SG Examination Delivery System that allows the application of a PDI qualified phased array ultrasonic (PAUT) and Eddy Current (ECT) examination that was previously qualified for examination of RPV nozzle DMWs to meet the requirements of examination of DMWs at the SG nozzle from the nozzle interior (ID). The SG-NExT is a remotely operated automated delivery system capable of performing automated PAUT and ECT ID examinations on Alloy 82/182 SG DMWs.

The performance of conventional OD UT examinations of these welds encounters many challenges, such as high radiation exposure, significant grinding of tapered areas, less effective coverage, and in most cases, inability to obtain encoded data. The SG-NExT not only overcomes these problems, but also provides many additional benefits. The compact SG-NExT is remotely deployed from the outside of the SG manway to minimize human exposure to high radiation doses. Applying this technology also allows utilities to drastically reduce the inspection frequency of Hot and Cold leg DMWs. The reduction in ISI scope will result in significant dose and dollar savings.

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