Safeguarding People, Assets & Uptime
Seismic retrofit strengthens existing power-plant structures and systems so they can withstand earthquake demands and return to service quickly. For nuclear facilities—and critical power assets across Arizona and the Southwest—seismic upgrades protect safety systems, reduce risk, and support license extensions.
New to Bunney’s? Learn who we are and explore our capabilities.
Why Seismic Retrofit Matters
Aging plants face new seismic maps, higher performance expectations, and evolving standards. Targeted upgrades help you:
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Protect safety-related systems and meet current design-basis/ beyond-design-basis goals
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Reduce unplanned outages and equipment loss during seismic events
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Improve operability and restart readiness after an earthquake
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Support regulatory compliance and long-term asset life
Most scopes are delivered during planned outages with defined hold points and QA/QC.
What We Retrofit (Typical Scopes)
Concrete & Steel Structures
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Containment, intake, cooling structures, auxiliary buildings
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Column/joint confinement, shear walls, collector elements, anchorage upgrades
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Fiber-reinforced polymer (FRP), steel jacketing, and section enlargement
Piping, Valves & Equipment
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Seismic bracing, snubbers/struts, guided supports, and restraint redesign
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Anchor-bolt upgrades and baseplates for pumps, heat exchangers, diesel gensets
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Controlled bolting/torque and post-install anchor qualification
Electrical & I&C
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Cable tray and conduit bracing, relay chatter mitigation
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Switchgear anchorage and equipment certification (shake-table/IEEE 344)
Cooling Towers & Balance of Plant (BOP)
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FRP/casing reinforcement, basin and fan-deck stiffening, drift-eliminator support
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Circulating/service-water pipe supports, expansion joints, and thrust blocks
Nonstructural Components
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Tanks, ducts, racks, platforms, access systems, and fall-protection tie-offs
Standards & Guidance We Follow
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ASCE 43 (Seismic Design for Safety-Related Nuclear Structures)
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ACI 349 (Nuclear safety-related concrete) and applicable ACI/ASTM test methods
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ASCE 7 (Seismic loads), AISC steel provisions
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IEEE 344 (Seismic qualification of equipment)
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NRC oversight, plant procedures, and owner specs (including PRA-informed decisions)
Our Retrofit Delivery Model
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Assessment & Walkdowns – Seismic evaluation, SQUG/EPRI-style screening, as-found anchorage review
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Engineering & Detailing – Nonlinear checks where needed; connection, anchor, and brace design
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Materials & Qualification – Procedure qualifications, mockups, and traceability
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Execution – Access planning, phased work in operating units or during outages
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Verification & Turnover – VT/UT/MT/RT as required, functional checks, as-builts, and complete QA packages
Arizona-Specific Considerations
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Soil-structure interaction for desert sites and reclaimed fills
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Thermal and UV exposure for exterior FRP, coatings, and anchors
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Monsoon wind/rain combined-hazard detailing for towers and auxiliaries
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Local permitting & utility coordination to keep outage windows on track
Why Bunney’s Inc.
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Proven nuclear & heavy-industrial experience in Arizona and the Southwest
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End-to-end delivery: evaluation, engineering coordination, retrofit construction, and documentation
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Outage-ready mobilization and schedule discipline
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Safety-first culture and site-specific training
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Traceable QA/QC with records ready for audits and license-basis documentation
Related Services:
FAQs
What’s typically the fastest-ROI seismic upgrade?
Anchorage and bracing of nonstructural systems (piping, trays, equipment) often reduce the largest risk at lower cost.
Can seismic retrofits be done while online?
Some non-safety scopes can proceed under controlled conditions; safety-related work is usually scheduled during planned outages with hold points.
Which codes apply to my plant?
For nuclear: ASCE 43, ACI 349, IEEE 344, and owner/NRC requirements. For BOP/industrial: ASCE 7, AISC, ACI, and site specs. We apply the correct standard per system classification.
How do you qualify post-installed anchors and braces?
By engineering design, manufacturer data, field proof tests (as specified), and documented inspections in the QA package.
Do you support multi-year seismic roadmaps?
Yes—prioritized lists, outage sequencing, and budget phasing aligned to risk reduction and license goals.
