Precision Welding for Critical Infrastructure
Nuclear-grade pipe welding is among the most demanding disciplines in industrial fabrication. It joins piping in primary and secondary systems—reactor coolant, steam, feedwater, and safety-related lines—where precision, integrity, and full regulatory compliance are non-negotiable. In Arizona and across the Southwest, Bunney’s Inc. delivers code-compliant welding that stands up to pressure, temperature, radiation exposure, and decades of service.
New to Bunney’s? Learn who we are and explore our capabilities.
What Sets Nuclear-Grade Welding Apart?
Nuclear work is governed by stringent codes and owner requirements, including:
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ASME Boiler & Pressure Vessel Code, Section III (nuclear components)
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ASME Section IX (welder and procedure qualification)
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NQA-1 quality assurance programs
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ASME B31.1/B31.3 where applicable to power/process piping
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Plant procedures under NRC oversight
Tight tolerances, validated procedures, and complete traceability define every weld.
Common welding processes
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GTAW (TIG): high control and purity for root and alloy work
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SMAW (stick): field versatility with qualified parameters
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Orbital GTAW: repeatable, high-integrity welds in constrained access
Materials Used in Nuclear Piping
Material choice balances radiation tolerance, corrosion resistance, and mechanical strength:
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Austenitic stainless steels: 304/304L, 316/316L, 347
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Nickel alloys: e.g., Inconel® for high-temperature/corrosive services
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Low-alloy steels: for specified pressure/temperature envelopes
Strict handling, storage, and cleanliness prevent contamination that can lead to porosity or inclusions. Heat numbers, MTRs, filler traceability, and purge control are documented in the QA package.
Field Realities & Welding Challenges
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Zero-defect expectations and narrow acceptance criteria
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Restricted access inside containment and radiologically controlled areas
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Preheat/interpass control and, where applicable, PWHT
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Continuous documentation: WPS/PQR/WPQ, weld maps, heat/lot control
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NDE & inspections: VT, PT/MT, UT/RT, and helium leak tests as specified
The Role of Supports, Valves & Alignment
Weld quality depends on the whole system. We install nuclear-grade valves, supports, snubbers, guides, and anchors per engineered details so thermal growth, vibration, and loads do not overstress welded joints. Controlled bolting/torquing and baseplate/anchor qualifications are verified and recorded.
Where Nuclear-Grade Welding Is Applied
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Commercial nuclear power plants (primary/secondary systems)
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Research reactors and medical isotope facilities
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Naval and specialized radioactive-materials operations
Each facility has distinct classifications and documentation needs—our QA program adapts accordingly.
Nuclear Pipe Welding in Arizona & the Southwest
Arizona’s fleet—anchored by Palo Verde Generating Station—relies on certified contractors who can mobilize quickly, work safely in controlled areas, and deliver audit-ready documentation. Bunney’s Inc. supports outage scopes and targeted repairs with disciplined planning and schedule control.
Why Work With Bunney’s Inc.
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Code-qualified welders & procedures: ASME Section IX, nuclear experience
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End-to-end delivery: shop/field fabrication, fit-up, welding, NDE, pressure tests
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Traceable QA/QC: weld maps, MTRs, filler control, purge logs, inspector sign-offs
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Safety-first culture: site-specific training and radiological work controls
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Outage-ready mobilization: plans built around hold points and owner oversight
From precision orbital welds to complex alloy procedures, we execute to spec and on schedule.
Project Lifecycle With Bunney’s
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Scope & Engineering Coordination – Joint design, materials, access planning
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Procedure Qualification – PQR/WPS/WPQ and mockups as required
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Controlled Fabrication & Fit-Up – Heat/lot tracking, purge control, interpass monitoring
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Inspection & Testing – VT/PT/MT/UT/RT, hydro/pneumatic per spec
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Turnover – As-builts, NDE reports, weld maps, and complete QA package
Related Services:
FAQs
Which code governs nuclear pipe welding?
ASME Section III for nuclear components, Section IX for qualifications, and NQA-1 for QA programs; B31.1/B31.3 may apply to scope boundaries.
How are welders and procedures qualified?
Through WPS/PQR/WPQ testing with documented variables, acceptance criteria, and renewal intervals—retained in the QA records.
What NDE is typical for nuclear welds?
Visual plus PT/MT for surface, and UT/RT for volumetric examination; additional pressure or leak tests per spec.
Can welding occur during operations?
Many scopes proceed under controlled conditions; safety-related work commonly aligns with planned outages and defined hold points.
Do you provide full traceability?
Yes—heat numbers, filler lots, purge logs, welder IDs, weld maps, and NDE reports are compiled in a turnover package suitable for audits.
