A tiny armada of between four and six unmarked drones flew over the Palo Verde Generating Station nuclear power plant in Arizona on the nights of September 29 and 30, 2019, with plant security proving unable to stop them and authorities still uncertain who was operating them or why.
Details about the incident were uncovered in a trove of documents released by the Nuclear Regulatory Commission after Dean Johnson, a researcher with the Scientific Coalition for Unidentified Aerospace Phenomena Studies, put in a Freedom of Information Act request with authorities.
During each incident, the drones reportedly flew through the secure perimeter, over the gates and into the plant proper, after which they hovered over the facility for some time before leaving.
In the documents obtained by Johnson, it’s specified that on September 29 at about 8:50 pm, security reported spotting five-six drones measuring about two feet in diameter flying about 200-300 feet over the plant, with red and white indicator lights flashing and spotlights turned on during approach. The lights were then turned off, and the UAVs idled near Reactor 3 for over an hour before leaving the area.
On September 30, at 8:51, four drones returned, with spotlights turned off this time, and again remained in airspace over the plant for some time before vanishing.
Documents indicate that the local sheriff’s office was notified about the incident, and searched for the drones and their operators in the vicinity, but turned up empty-handed. The FBI, the Federal Aviation Administration and Department of Homeland Security were contacted.
Potential Security Risk
The Palo Verde NPP generates about 1/3 of all of Arizona’s electricity, and in addition to customers in that state, exports part of its juice to New Mexico, Nevada, California and Texas.
Speaking to the Arizona Republic newspaper about the incident, Palo Verde site services vice president Mike McLaughlin said that “there did not appear to be coordinated movements between the drones,” and noted that their nighttime flight made it difficult to determine their exact number, size or altitude.
Arizona’s laws prohibit the operation of unmanned aerial vehicles less than 500 feet above “critical infrastructure,” with FAA guidelines prohibiting operations below 400 feet at “designated national security sensitive facilities.”
The FBI reportedly coordinated with the Nuclear Regulatory Commission after the second incident, but the regulator concluded that “there are currently no risk-significant vulnerabilities to nuclear power plants that could be exploited by adversarial use of commercial drones to result in radiological sabotage, or theft or diversion of special nuclear material.”
These sentiments were echoed in the documents obtained by Johnson, with one official writing the incidents off as a “drone-a-palooza” in an email, and Laura Pearson, official in charge of the Nuclear Regulatory Commission’s intelligence and threat assessment branch, writing in another email that calls about the drone incidents would only be handled during regular office hours, and that her staff shouldn’t be bothered about them in the middle of the night.
Not all observers are so nonchalant, however. DroneDJ, a drone-industry related news site, suggested that the large size of the drones indicates that they “weren’t a common off-the-shelf type and were likely something custom made or manufactured for commercial or military use.”
“Let’s say the drones were equipped with explosives or were a kamikaze-style [design] – they could have been able to hit various pipelines and vital areas within the power plant, causing it to slow down energy production at the minimum. If the drones were powerful enough, they could likely knock out a power plant that provides Arizona with 35 percent of its power and supplies power to Phoenix and Tucson, San Diego and Los Angeles,” the outlet warned.
Last year, a massed drone attack on two major Saudi Aramco facilities by Yemen’s Houthi militia temporarily wiped out half of the Kingdom’s oil output. In his analysis of the Palo Verde incidents, Forbes contributor David Hambling suggested that the Saudi attack “should be a wakeup call that such unmanned precision strikes are not just the preserve of state actors anymore.”
The War Zone similarly warned that the events highlight concerns about the dangers of a potential “adversarial attack” involving small unmanned aircraft and the need ensure that there are adequate defences against them. The outlet blasted the helpless "and even cavalier attitude” of those tasked with ensuring security at the nuclear plant, suggesting the incident “serves as an alarming and glaring example of how neglected and misunderstood this issue is.”
What Were the Drones Doing?
Saying that the intruders may now “have highly detailed maps” of the Palo Verde plant “showing the exact location of every valve, pipe, switch and control,” the Forbes contributor suggested that the plans may have been sold on the dark web, or set aside for later use. “Either way, it is an alarming demonstration of how easily drone intruders can now go anywhere anytime they wish,” he warned.