Within Readiness
Why Palo Verde Was More Than a Drone Sighting
The Palo Verde case shows why seeing drones near a nuclear plant is not the same as finding the operator or understanding intent.
On this page
- What was reported near the plant
- Why operator attribution mattered
- What the case reveals about response limits
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Introduction
The 2019 drone incursions at the Palo Verde Nuclear Generating Station in Arizona are one of the clearest examples of a problem that often gets lost in discussions about unidentified objects near sensitive facilities: detection is not the same thing as attribution. Security personnel knew that drones were present. They observed their movements, reported the incidents, and involved multiple government agencies. Yet the operators were never publicly identified, their intentions remained unclear, and the event exposed limits in the ability of authorities to respond to unknown aerial activity around critical infrastructure. [The War Zone]twz.comthe night a drone swarm descended on palo verde nuclear power plantThe War ZoneThe Night A Mysterious Drone Swarm Descended On Palo…30 Jul 2020 — Rodriguez reported that a number of drones were flying…
Within the broader subject of UFOs and nuclear weapons, Palo Verde is significant precisely because it does not require extraordinary explanations. The case demonstrates how conventional drones can create uncertainty around a nuclear facility and how difficult it can be to determine who is responsible, what they are doing, and whether they pose a genuine threat. [CSG Midwest]csgmidwest.orgCSG MidwestDrones and Nuclear Power Plant SecurityOctober 27, 2020 — The NRC asks nuclear power plant licensees to voluntarily report any…
What Was Reported Near the Plant
The incident occurred on the nights of 29 and 30 September 2019 at the Palo Verde Nuclear Generating Station, the largest nuclear power plant in the United States. According to Nuclear Regulatory Commission (NRC) records released through Freedom of Information Act requests, security personnel observed multiple drones operating near Unit 3 and other protected areas of the site. Reports described groups of approximately five or six drones during at least one of the incursions. [The War Zone+2Forbes]twz.comthe night a drone swarm descended on palo verde nuclear power plantThe War ZoneThe Night A Mysterious Drone Swarm Descended On Palo…30 Jul 2020 — Rodriguez reported that a number of drones were flying…
The activity was not a brief overflight. Internal accounts indicated that some of the drones remained in the area for extended periods, moving around the facility in ways that attracted security attention. Officials regarded the behaviour as unusual enough to notify federal authorities and initiate broader reporting procedures. The FBI, Federal Aviation Administration (FAA), Department of Homeland Security, local law enforcement and the NRC all became involved in subsequent investigations. [The War Zone+2The Debrief]twz.comthe night a drone swarm descended on palo verde nuclear power plantThe War ZoneThe Night A Mysterious Drone Swarm Descended On Palo…30 Jul 2020 — Rodriguez reported that a number of drones were flying…
What makes Palo Verde notable is not merely that drones appeared near a nuclear plant. Drone sightings around critical infrastructure have occurred elsewhere. Rather, the Palo Verde case produced unusually detailed documentation showing that trained observers saw the aircraft, tracked them, and still struggled to determine who controlled them or why they were there. [Forbes]forbes.comdrone swarm invaded palo verde nuclear power plantForbes'Drone Swarm' Invaded Palo Verde Nuclear Power Plant…30 Jul 2020 — A number of small drones flew around a restricted area at Pal…
Why Operator Attribution Mattered
The central question was never simply, “Were there drones?” The available evidence strongly suggests there were. The harder question was who was flying them.
Several possibilities existed:
- Recreational operators acting irresponsibly.
- Commercial operators conducting unauthorised activity.
- Hobbyists unaware of restrictions.
- Individuals intentionally testing security responses.
- Actors gathering intelligence about the facility.
- A coordinated exercise or operation that had not been properly communicated to site personnel.
The challenge was that observation alone could not distinguish among these explanations. A drone carrying a camera can look identical whether its purpose is photography, curiosity, criminal reconnaissance or intelligence collection. The same flight pattern can support multiple interpretations. [CSG Midwest]csgmidwest.orgCSG MidwestDrones and Nuclear Power Plant SecurityOctober 27, 2020 — The NRC asks nuclear power plant licensees to voluntarily report any…
This distinction is critical for nuclear security. A security team can react differently if it knows a drone belongs to a nearby contractor than if it suspects a hostile reconnaissance effort. Without attribution, decision-makers are forced to operate under uncertainty. The event becomes not just an airspace issue but an intelligence problem. [CSG Midwest]csgmidwest.orgCSG MidwestDrones and Nuclear Power Plant SecurityOctober 27, 2020 — The NRC asks nuclear power plant licensees to voluntarily report any…
Internal discussions reported after the incident reflected concern that the drones appeared capable of conducting a deliberate survey of the site. However, concern is not proof. The operators were not publicly identified, and no publicly available evidence established a hostile motive. The inability to move from observation to attribution was therefore the most important unresolved aspect of the case. [Forbes]forbes.comDozens More Mystery Drone Incursions Over U.S7, 2020 — In the September incidents, a swarm of five or six large drones flew over the Unit 3 nuclear reactor at Palo Ver…
Why Seeing a Drone Did Not Mean Controlling the Situation
One of the most revealing lessons from Palo Verde was that detecting an aircraft does not automatically provide the means to stop it.
At the time, nuclear plant security personnel had significant responsibilities for protecting facilities but limited authority to interdict aircraft. NRC guidance noted that plant security forces generally could not simply shoot down drones or employ aggressive countermeasures on their own authority. Reports were instead passed to federal and local agencies responsible for aviation and law enforcement. [CSG Midwest]csgmidwest.orgCSG MidwestDrones and Nuclear Power Plant SecurityOctober 27, 2020 — The NRC asks nuclear power plant licensees to voluntarily report any…
That creates a timing problem. Small drones can appear, conduct surveillance, and leave before investigators locate the operator. Even if authorities know a drone is present, finding the pilot may require tracking radio signals, identifying launch locations, coordinating multiple agencies and overcoming legal constraints. By the time those processes occur, the aircraft may be gone. [CSG Midwest]csgmidwest.orgCSG MidwestDrones and Nuclear Power Plant SecurityOctober 27, 2020 — The NRC asks nuclear power plant licensees to voluntarily report any…
The Palo Verde incident therefore highlighted a gap between awareness and action. Security personnel could report the intrusion, but converting that awareness into rapid attribution and intervention proved far more difficult. [Forbes]forbes.comdrone swarm invaded palo verde nuclear power plantForbes'Drone Swarm' Invaded Palo Verde Nuclear Power Plant…30 Jul 2020 — A number of small drones flew around a restricted area at Pal…
What the Case Reveals About Response Limits
The broader lesson from Palo Verde is not that an attack occurred. No public evidence shows that the drones damaged equipment, interfered with reactor operations, or represented an imminent threat. The significance lies elsewhere. [dedrone.com]dedrone.comthe importance of anti drone systems in power plantsThe Importance of Anti-Drone Systems in Power Plants25 Apr 2023 — Although no damage was reported at Palo Verde, open questions remain ab…
The incident demonstrated three practical limits that are relevant whenever unidentified aerial activity is reported near nuclear facilities:
Detection does not equal identification. Security personnel may know something is present without knowing exactly what it is or who controls it. Palo Verde illustrates this distinction clearly. [The War Zone]twz.comthe night a drone swarm descended on palo verde nuclear power plantThe War ZoneThe Night A Mysterious Drone Swarm Descended On Palo…30 Jul 2020 — Rodriguez reported that a number of drones were flying…
Identification does not equal attribution. Even when observers conclude that an object is a drone rather than a mysterious unknown, the operator and purpose may remain uncertain. The most important questions can remain unanswered after the object itself has been classified. [Forbes]forbes.comDozens More Mystery Drone Incursions Over U.S7, 2020 — In the September incidents, a swarm of five or six large drones flew over the Unit 3 nuclear reactor at Palo Ver…
Attribution does not guarantee response. Legal authorities, technical capabilities and coordination requirements may prevent immediate action even when a potential threat is recognised. Subsequent discussions within the NRC and wider security community reflected concern that existing counter-drone measures were inadequate for this type of scenario. [The War Zone+2WIRED]twz.commassive uptick in official drone sightings by nuclear power plantsThe War ZoneNuclear Power Plants Report Massive Uptick In Drone…Dec 21, 2024 — In a trove of documents and internal correspondences re…
These lessons help explain why incidents around nuclear sites can generate public speculation. Observers may see unexplained activity and conclude that the mystery lies in the object itself. In cases such as Palo Verde, the deeper mystery is often attribution: who was responsible, what they intended, and whether authorities could have stopped them if necessary. [Forbes]forbes.comdrone swarm invaded palo verde nuclear power plantForbes'Drone Swarm' Invaded Palo Verde Nuclear Power Plant…30 Jul 2020 — A number of small drones flew around a restricted area at Pal…
Why Palo Verde Remains Relevant
Palo Verde remains a useful case study because it strips away the need for exotic explanations. The aircraft were widely regarded as drones, not unknown craft exhibiting impossible capabilities. Yet the event still exposed a significant security challenge. Multiple drones operated around a highly sensitive facility, attracted the attention of numerous agencies, and nevertheless left behind unresolved questions about their operators and objectives. [The War Zone+2Forbes]twz.comthe night a drone swarm descended on palo verde nuclear power plantThe War ZoneThe Night A Mysterious Drone Swarm Descended On Palo…30 Jul 2020 — Rodriguez reported that a number of drones were flying…
For discussions of nuclear readiness risks without alien assumptions, that is the key takeaway. The most consequential uncertainty was not what flew over the plant. It was whether authorities could rapidly identify who was behind it, understand the purpose of the operation, and respond effectively before the opportunity had passed. [CSG Midwest+2WIRED]csgmidwest.orgCSG MidwestDrones and Nuclear Power Plant SecurityOctober 27, 2020 — The NRC asks nuclear power plant licensees to voluntarily report any…
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Endnotes
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Source: forbes.com
Title: drone swarm invaded palo verde nuclear power plant
Link: https://www.forbes.com/sites/davidhambling/2020/07/30/drone-swarm-invaded-palo-verde-nuclear-power-plant/Source snippet
Forbes'Drone Swarm' Invaded Palo Verde Nuclear Power Plant...30 Jul 2020 — A number of small drones flew around a restricted area at Pal...
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Source: nrc.gov
Title: fs drone pwr plant security
Link: https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/fs-drone-pwr-plant-securitySource snippet
Nuclear Regulatory CommissionDrones and Nuclear Power Plant SecurityThe Nuclear Regulatory Commission updated its regulations in 2024 to...
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Source: forbes.com
Title: Dozens More Mystery Drone Incursions Over U.S
Link: https://www.forbes.com/sites/davidhambling/2020/09/07/dozens-more-drone-incursions-over-us-nuclear-power-plants-revealed/Source snippet
7, 2020 — In the September incidents, a swarm of five or six large drones flew over the Unit 3 nuclear reactor at Palo Ver...
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Source: dedrone.com
Title: the importance of anti drone systems in power plants
Link: https://www.dedrone.com/blog/the-importance-of-anti-drone-systems-in-power-plantsSource snippet
The Importance of Anti-Drone Systems in Power Plants25 Apr 2023 — Although no damage was reported at Palo Verde, open questions remain ab...
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Source: wired.com
Title: Now the threat looms over the US homeland.Read more
Link: https://www.wired.com/story/us-military-mystery-drones-response/Source snippet
Why the US Military Can't Just Shoot Down the Mystery...13 Dec 2024 — Small, easily weaponizable drones have become a feature of ba...
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Source: nrc.gov
Link: https://www.nrc.gov/docs/ML2033/ML20332A109.pdfSource snippet
Nuclear Generating Station] early in the week getting a lot of attention in the.Read more...
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Source: nrc.gov
Title: foia march
Link: https://www.nrc.gov/reading-rm/foia/recent-requests/2020/foia-marchSource snippet
Recent FOIA Requests – March 2020... 2019, inclusive, pertaining to an incursion of drones within the base parameter surrounding the Palo...
Published: March 2020
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Source: twz.com
Title: the night a drone swarm descended on palo verde nuclear power plant
Link: https://www.twz.com/34800/the-night-a-drone-swarm-descended-on-palo-verde-nuclear-power-plantSource snippet
The War ZoneThe Night A Mysterious Drone Swarm Descended On Palo...30 Jul 2020 — Rodriguez reported that a number of drones were flying...
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Source: csgmidwest.org
Link: https://csgmidwest.org/wp-content/uploads/2021/01/NRC-Drones-Memo.pdfSource snippet
CSG MidwestDrones and Nuclear Power Plant SecurityOctober 27, 2020 — The NRC asks nuclear power plant licensees to voluntarily report any...
Published: October 27, 2020
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Source: thedebrief.org
Title: The Debrief U.S
Link: https://thedebrief.org/u-s-department-of-energy-uap-documents-reveal-puzzling-aerial-incursions-near-american-nuclear-sites/Source snippet
Department of Energy UAP Documents Reveal...Sep 29, 2023 — Johnson revealed sightings of swarms of large drones that were observed on Se...
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Source: Wikipedia
Title: Palo Verde Nuclear Generating Station
Link: https://en.wikipedia.org/wiki/Palo_Verde_Nuclear_Generating_StationSource snippet
Palo Verde Nuclear Generating StationThe Palo Verde Generating Station is a nuclear power plant located near Tonopah, Arizona about 45...
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Source: twz.com
Title: massive uptick in official drone sightings by nuclear power plants
Link: https://www.twz.com/news-features/massive-uptick-in-official-drone-sightings-by-nuclear-power-plantsSource snippet
The War ZoneNuclear Power Plants Report Massive Uptick In Drone...Dec 21, 2024 — In a trove of documents and internal correspondences re...
Additional References
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Source: reddit.com
Link: https://www.reddit.com/r/nuclear/comments/iqtf6y/drones_invade_airspace_above_palo_verde/Source snippet
Drones invade airspace above Palo Verde: r/nuclearHalf a dozen drones flew over the Unit 3 reactor for 80 minutes, long enough to map an...
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Source: facebook.com
Link: https://www.facebook.com/aniruddhabapudevotee.page/posts/nuclearsafety-several-small-drones-flew-over-palo-verde-nuclear-power-plant-in-t/3148015278653303/ -
Source: 6abc.com
Link: https://6abc.com/post/fact-check-drones-were-not-tracking-missing-radioactive-material-new-jersey-department-energy-related-officials-say/15670972/Source snippet
Drones were not tracking missing radioactive material in...Dec 18, 2024 — A theory that missing radioactive material could be linked to...
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Source: mavicpilots.com
Link: https://mavicpilots.com/threads/%E2%80%98drone-swarm%E2%80%99-invaded-palo-verde-nuclear-power-plant-last-september-%E2%80%94-twice.94941/Source snippet
"'Drone Swarm' Invaded Palo Verde Nuclear Power Plant Last...31 Jul 2020 — Documents gained under the FoIA show how small drones flew ar...
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1, 2, and 3, Consideration of Approval of Transfer of License.Read more...
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Source: rocketryforum.com
Link: https://www.rocketryforum.com/threads/the-night-a-mysterious-drone-swarm-descended-on-palo-verde-nuclear-power-plant.160965/Source snippet
29, 2019. Shortly before 11:00 PM local time at the Palo Verde Nuclear Generating Station, Daphne...
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Source: toddheberlein.com
Title: Mysterious Overflights: Drone Swarms over Critical U.S
Link: https://www.toddheberlein.com/blog/2025/1/4/mysterious-overflights-drone-swarms-over-critical-us-locationsSource snippet
Jan 4, 2025 — Swarm 2: Palo Verde Nuclear Generating Station, September 2019 · Between five and six drones were involved · The swarm inci...
Published: September 2019
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Source: dronexl.co
Title: mysterious drone swarm palo verde nuclear power plant
Link: https://dronexl.co/2020/07/30/mysterious-drone-swarm-palo-verde-nuclear-power-plant/Source snippet
Mysterious Drone Swarm Flew Over Palo Verde Nuclear...Jul 30, 2020 — On two evenings in September last year, a mysterious drone swarms w...
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Title: quad cities violations lead to nrc confirmatory order
Link: https://www.ans.org/news/2025-08-06/article-7261/quad-cities-violations-lead-to-nrc-confirmatory-order/Source snippet
6 Aug 2025 — The Nuclear Regulatory Commission has sent a confirmatory order to Constellation Energy Generation outlining the agreed-on a...
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Source: facebook.com
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eased, the NRC initiated a technical analysis with Sandia...Read more...
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