Specialty Machining and Code Repairs
BWX Technologies, Inc. (BWXT) has full capabilities for performing repairs to ASME Code pressure vessels. We have all ASME and National Board certifications (N, NPT, NA, NS, and NR) required for the performance of design, modification and repair activities. In addition, we have the engineering analysis expertise, tooling, procedures and field personnel to deliver these services.
Machining Services
BWXT has designed, built and qualified portable tooling for manway/hand hole cover and gasket surface machining, the addition of hand holes and instrument ports to steam generators (SG) and other pressure vessels, the removal of stuck studs and other specialty machining applications. BWXT utilizes both commercially available and custom-designed tooling to perform machining processes.
For flange facing, our robust tooling design includes hardened slides and ball screws to eliminate backlash while ensuring a continuous depth-of-cut and removal of as little as 0.0005 inches of material; this, in turn, allows for the creation of a phonographic finish that’s ideal for ideal surface sealing. Additionally, our tooling is designed for quick setup to increase efficiency and reduce dose. Custom shielding further reduces dose and serves as a foreign material exclusion barrier. Our machining specialists validate the process on realistic mock-ups prior to the job so they can provide a quality repair.
For SG manway stuck stud removal, BWXT has designed a versatile system that works on steam generators for various manufacturers and for different stud types and lengths. Our machining system has a modular design that includes a base fixture, a feed rack and a power unit. The variable output electric motor driver provides the wide range of speed and power necessary for drilling and tapping holes of various sizes. The components are designed for ease of assembly at the manway and incorporate a shield plug to reduce operator dose. Precision adjustments to tolerances of +/- 0.005 inch allow for the clean removal of a stud without damage to the stud hole threads, which permits a return to service without helicoil or insert installation.
Welding Services
BWXT has an extensive library of registered weld procedure specifications available should welding repairs be required. Our engineered weld solutions include both portable manual equipment and customized automatic welding equipment. Our extensive knowledge of repair techniques for stainless steels, NiCr, modified Cr-Mo, and numerous other steel alloys is vast. Our expertise in temper-bead welding allows us to perform repairs on material that typically requires post-weld heat treatment when post-weld heat treatment is not possible. Specialty welding applications performed by BWXT include SG tube-to-tubesheet seal weld repairs, small nozzle repairs and storage tank repairs. We have developed and deployed custom solutions for feeder tube repairs with as little as one-inch working clearance around piping in high-dose regions.
Key Features and Benefits:
- Experienced OEM and engineering service provider with extensive code repair capability and expertise
- Routinely perform complex machining tasks such as flange face machining, installation of vessel inspection ports and other specialty machining tasks
- Proven equipment and processes with a history of successful deployment in challenging environments
- Digital controls with simple, intuitive operator interfaces
- Extensive mock-up facilities for custom tooling development and in-house training