During a recent refueling outage, replacement was required of a critical 6" stainless-steel Reactor Coolant System primary check valve. The valve was approximately 24 inches long and 600 lbs. and was located in a tight, congested area. Special considerations were required as the valve and associated piping were very contaminated.
Because of successful prior project experiences, the utility called on Tri Tool Services. Working closely with the site Projects and Modifications Contractor, Tri Tool responded with a crew of pipe fitters, machinists and welders within 24 hrs.
Alongside radiological control personnel, Tri Tool had to remove the old valve with a minimum of debris to remain within the plant requirements for Foreign Material Exclusion. Personnel safety considerations associated with the task were integrated into the Job Safety Analysis while developing the action plan for mitigation of the project's operational and radiological hazards.
Utilizing Tri Tool's Model 212B BevelMASTER® ID beveler and Model 608 SB Clamshell lathe the existing valve cut-out and removal was precisely executed to exacting customer specifications.
Tri Tool's welders were tested and pre-qualified to TVA's Quality Program and the replacement check valve was installed through a teaming effort of Tri Tool and utility personnel. The fit-up was extremely critical and was closely monitored by the site's QC and QA personnel.
The project was completed with no safety or human error issues due to the diligent and thorough (albeit emergent and rapid) planning efforts of Tri Tool and the entire site team.
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| Tri Tool's welders at Sequoyah Nuclear were tested and qualified to TVA's Quality Program and welds performed by them exceeded all acceptable, prescribed standards. |
Post welding of all large bore welds required an In-Service Inspection of the final weld profile. Additionally, the welds were subjected to 100% radio graphic testing acceptance criteria as called out in ASME Section IX, and all initial welds done under these requirements by Tri Tool's welders exceeded all acceptable, prescribed standards.
"The professionalism of their project manager, machinists and welders was exemplary and the quality of their work was beyond compare... I will continue to work with Tri Tool and would highly recommend this company."
David Charles Haney, Modifications Manager, TVA - Sequoyah Nuclear
Contact Tri Tool for rapid response, unequaled support, excellent equipment and our total commitment to safe, error-free performance.