On the 19th, an unfamiliar flying object appeared on a screen in the integrated situation room at the Saeul Nuclear Power Headquarters in Ulju County, Ulsan. It signaled that an unauthorized drone had emerged near the nuclear plant. Situation room staff checked the drone's location and direction of movement displayed on the screen and immediately began response procedures.
The scene released that day showed the process of responding to an illegal drone during the full-scale physical protection drill at the Saeul nuclear plant that runs for four days starting on the 18th. The drill scenario assumed a situation in which a drone carrying explosives approached the plant site. Under current rules, the area around a nuclear plant is a no-fly zone where drones cannot be freely flown.
The drill was conducted as if real, with Korea Hydro & Nuclear Power Co. (KHNP), the plant operator, unaware in advance of the drone's infiltration route. In practice, when a drone came close to the plant, a radio frequency (RF) scanner first detected it. An RF scanner is a device that captures the wireless signals exchanged between a drone and its controller. Before visually confirming the drone, it analyzes signal traces to identify the drone's location, the operator's location, the model, and more within a radius of about 3 kilometers.
After detection, the situation was relayed. KHNP initiated the initial response, and communication lines with relevant agencies, including the military, police, and fire authorities, were activated. Depending on the distance between the drone and the plant, the response level is raised from attention to caution, alert, and critical.
As the drone approached the plant site boundary, on-site security personnel began procedures to deploy a handheld jammer. A jammer is a signal-jamming device that disrupts a drone's control signals or positioning signals, making normal flight difficult. The aim is to stop the drone, force it to return, or prevent it from approaching its target any further.
However, the jammer was not actually used that day. Because signal-jamming equipment can affect nearby communications and residents' daily lives, its use is restricted in drills under current rules.
Nuclear Safety and Security Commission Chairperson Choi Won-ho said, "There were restrictions on using jammers under the Radio Waves Act, but we worked with the Ministry of Science and ICT to revise the relevant law," adding, "When the revised law takes effect in the second half of this year, jammers will be available for use in drills as well."
The drill continued to a scenario in which a drone loaded with explosives entered the site and detonated. Smoke rose from the drone that had virtually crashed, followed by subsequent measures, including on-site access control, fire suppression, explosive analysis, securing the operator, and handing the operator over to police. The Nuclear Safety and Security Commission evaluated whether the entire process—from detection to neutralization preparations, interagency coordination, and post-incident response—functioned properly.
The Saeul nuclear plant currently operates multiple layers of protection: a grade III protected area inside the outer fence, a grade II protected area inside the power station, and a vital area that includes the reactor building and the nuclear fuel building.
In 2015, the Nuclear Safety and Security Commission incorporated drone threats into the Design Basis Threat (DBT), the standard for nuclear plant protection. DBT is the maximum threat that a plant operator is responsible for preventing. It then introduced handheld jammers in Dec. 2021 and RF scanners in Mar. 2023. It is also operating a pan-government task force (TF) on responding to illegal drones around nuclear facilities together with related ministries and nuclear operators, maintaining a cooperation system capable of countering aerial threats.
Choi added, "However, RF scanners have difficulty detecting drones that are unregistered or outside the detectable frequency range," noting, "We are strengthening our response capability by introducing a paired set of radar and cameras that can detect drones regardless of frequency. They are scheduled to be installed at the Wolseong plant within this year and will be expanded in stages thereafter."
Choi said, "At a time when energy security has become extremely important due to the recent Middle East war, responding to physical attacks such as drones is also highly significant for a stable power supply," adding, "Through effective drills, we will continue to ensure that nuclear plants establish protection systems that are effective against new threats."