Underwater Nuclear Welding

UCC is recognized as the most experienced and qualified underwater welding company in the nuclear industry. We have completed more than three decades of safety related nuclear underwater welding projects on various reactor components. In addition, we have qualified procedures and have performed welding on carbon and stainless-steel components in suppression pools, condensate storage tanks, and other safety-related water storage basins.

Our comprehensive welding capabilities include:

  • In-vessel welding cladding repair

  • Core spray tee Box modifications and repairs

  • Feedwater sparger replacement

  • Steam dryer modification and repairs

  • Spent fuel pool leak detection and weld repairs

  • Seismic support modifications

  • Fuel pool liner installation

  • Feedwater sparger modification and repairs

  • Steam separator modification and repairs

  • Transfer cart modification and repairs

  • Safety-related pipe hangers and supports

  • Traveling water screen repair

  • Trash rack and gate repair

  • Pipe hangers and supports

Industry Leading Underwater Welders and Processes

New essex building tankUCC qualifies nuclear underwater welders and welding procedures in our pressurized wet pot chamber in order to simulate exact production welding depths. UCC’s underwater hyperbaric welding facility in Essex, Connecticut, is one of the largest of its kind. The hyperbaric tank was designed exclusively for the nuclear underwater welding industry and can achieve a simulated depth of 95 feet. The tank is 12 feet in diameter and 18 feet high and is equipped with an access hatch large enough for mock-up sections to pass through for assembly inside the tank. It is also equipped with a 24-inch view port to allow customer and quality control personnel to monitor diver’s activities.

With the top nuclear industry welders, UCC’s specialized maintenance support includes underwater nuclear welding procedures qualified in accordance with ASME Section IX, ASME Section XI, IWA 4660 (formerly Code Case N-516) and AWS D3.6. The ASME procedures are qualified for all position groove welds on stainless steel plate and pipe. UCC has qualified carbon steel welding procedures to ASME Section XI IWA 4660, P1 to P1 base metal using an E309L-16 filler. The procedures were qualified for metals with a carbon equivalent of up to 0.525.

Additional certifications, qualifications and procedures include:

  • ASME Section IX, ASME Section XI, IWA 4660 (formerly Code Case N-516).

  • AWS D3.6. The ASME procedures are qualified for all position groove welds on stainless steel plate and pipe.
  • Carbon steel welding procedures to ASME Section XI IWA 4660, P1 to P1 base metal using an E309L-16 filler. The procedures were qualified for metals with a carbon equivalent of up to 0.525.
  • Welding procedures for mild carbon steel using an E7014 filler for carbon equivalents up to 0.495 have also been qualified in accordance with AWS D 3.6.
  • Quality assurance manual – This governs the overall application of our quality assurance program in accordance with 10CFR50, Appendix B, NQA-1 and ANSI N45.2.
  • GWP-SMAW-1A (general welding procedure) – This procedure governs shielded metal arc welding qualification requirements (dry and wet).
  • GWPQ-SMAW-1A (general welding performance qualification) – This procedure governs the qualification process of all welders’ qualifications (dry and wet).
  • WPS (welding procedure specification) – The WPS is written in accordance with ASME Section XI, IX and/or AWS D3.6.M.
  • PQR (procedure qualification record) – In accordance with applicable welding codes, a welder produces a test coupon and the coupon is tested in accordance with ASME or AWS acceptance criteria. If the test is successful, then the PQR document serves to prove that the WPS is valid.

  • WPQ (welder performance qualification) – Once the WPS has been certified, welders may test and become certified to weld within the parameters indicated on the WPS. They weld a test coupon, which is then tested in accordance with ASME or AWS criteria. If the test passes, the WPQ document serves as the documentation and that welder’s successful completion and certification.

Underwater Nuclear Services You Can Rely On

With a pioneering legacy as the first commercial diving company to specialize in nuclear services for power plants, UCC has established an unparalleled benchmark for safety, reliability and cost-effectiveness, meeting the expectations of industry leaders. Our team of experts possesses in-depth knowledge of the intricate challenges inherent to nuclear facilities, allowing us to deliver customized solutions that address the unique requirements of this rigorously regulated and safety-driven industry.

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Experience the UCC Advantage

The expertise of our nuclear divers, combined with state-of-the-art equipment, deliver the highest standards of quality, integrity and safety in every welding project. Reach out to our experts to discuss your underwater nuclear welding needs and together, we will optimize the performance of your nuclear facility.

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