Drones at nuclear power plants: enemies or helpers?

By David Lochbaum | March 23, 2015

In the 1939 film “The Wizard of Oz,” Glinda, Witch of the North, asks Dorothy if she is a good witch or a bad witch. “Who, me?” asks Dorothy. “Why, I’m not a witch at all. I’m Dorothy Gale from Kansas.” Not long afterward, of course, viewers are introduced to the Wicked Witch of the West. It’s easy to tell good and bad witches apart because, as the beautiful Glinda explains, “Only bad witches are ugly.” If only it were that easy to tell good drones from wicked ones.

Reports of unmanned aerial vehicles flying over more than a dozen nuclear power plants in France within the past year raised concerns about drones doing bad things. At the same time, experts are examining how drones—in the hands of the right people—might be able to increase nuclear plant safety levels. The key is to distinguish good drones from bad ones.

Good deeds by good drones. Drones can be remotely controlled by a human pilot or programmed to follow pre-specified routes. Drones can travel into airborne radioactive plumes without exposing pilots and crew to radiation. Pre-programmed drones may be able to undertake some missions while humans are busy with other necessary tasks. These capabilities can all be extremely useful after a nuclear accident.

For example, nuclear power plant owners and regulators in the United States are assessing whether drones can perform key functions following accidents. Drones may be able to supplement notification systems (for example, emergency sirens and tone-alert radios) by emitting siren-like sounds that alert people to turn on televisions and radios to hear official declarations about any precautionary measures authorities are recommending. Drones may also be able to augment radiation monitoring by flying routes downwind of the stricken facility and relaying continuous radiation readings back to an emergency response center. This radiation level information would fill in gaps between the existing ground-based detectors.

Drones already demonstrated a post-accident capability by flying around the Fukushima Daiichi site and sending back video and other information to workers seeking to understand the extent of the damage inflicted by hydrogen explosions.

Bad deeds by bad drones. But drones have a potential dark side. Reports of drones buzzing around French nuclear plants prompted considerable discussion about whether drones carrying explosives could wreak damage. The short answer is yes. The longer answer is that the steps mandated by the Nuclear Regulatory Commission (NRC) after the 9/11 tragedy, to reduce nuclear plant vulnerabilities to damage inflicted by a piloted aircraft on a suicide mission, also protect against explosive-laden drones. The NRC’s post-9/11 upgrades did not eliminate the suicide aircraft threat entirely, however, and multiple explosive-laden drones might be able to overwhelm the upgrades. But substantial improvements have already been implemented, such that the drone hazard may only require re-evaluation and modest tweaking to narrow any gaps in existing measures.

Drones may pose a larger threat to nuclear plants by performing other roles. For example, workers and vehicles are searched for weapons and explosives before entering the security fences around a nuclear plant; the fences are equipped with intrusion detection systems that prevent anyone from entering the plant except via the security gates and checks. Drones could fly over the fences, though, to deliver guns and small explosives to individuals inside. If these deliveries went undetected, the security responders at the site could find themselves outgunned or outmaneuvered by armed attackers already inside the perimeter fences.

In addition, drones could distract the plant’s security responders. Similar to how military pilots use countermeasures to confuse incoming missiles, ground-based attackers could employ drones to lure security responders away from an attack route. In the force-on-force exercises conducted periodically to test nuclear plant security capabilities, mock attackers penetrate fences and proceed rapidly through the plant, simulating the destruction of equipment needed to cool the reactor core. Security personnel respond to intrusion-detection alarms and to indications that locked doors have been blown open by rushing to take defensive positions behind bullet-resistant enclosures—located between the intruders and the remaining equipment that could trigger a meltdown if sufficiently damaged. (The NRC and the nuclear industry refer to the list of this equipment as the Target Set, details of which are not publicly available for obvious reasons.)

The exercises have demonstrated that the responders need not be delayed long to tilt the advantage in favor of the attackers. Drones broadcasting loud sounds of explosions and gunfire, for example, could confuse and slow down the responders. Likewise, collisions with the perimeter fence—activating the intrusion-detection system—could send responders on time-consuming wild drone chases.

Needed deeds by the drone police. Clearly, drones are double-edged swords: They can perform critical functions to protect the public in event of a nuclear plant accident, but they can also perform tasks that could cause a nuclear plant disaster. How can authorities permit good drones while prohibiting bad ones?

The NRC should revise its design basis threat (DBT)—which provides “a general description of the attributes of potential adversaries who might attempt to commit radiological sabotage or theft or diversion against which [the power plant] licensee's physical protection systems must defend with high assurance”—and associated adversary characteristics guidance to define the potential hazards posed by bad drones. The DBT and associated guidance establish parameters such as the number of ground-based attackers, the kinds of weapons they might carry, and the tactics they could use—and plant owners must develop security measures to thwart these scenarios. Revised parameters would add drones to the bad guys’ arsenal, and the NRC’s security inspections—including force-on-force tests—would then determine whether the measures taken by plant owners provide sufficient protection.

In Dorothy’s imaginary world, eliminating the Wicked Witch of the West turned out to require nothing more than a bucket of water: “Look what you’ve done! I’m melting! Melting!” screamed the witch as she faded away. Unfortunately, vanquishing bad drones won’t be that easy. Real action is needed to ensure that bad drones do not someday cause a very bad thing to happen at a US nuclear power plant.

(David Lochbaum is director of the Nuclear Safety Project for the Union of Concerned Scientists. He prepared this article on his own time, and it may not represent the views of the organization.)

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