Kola NPP Engineers Upgrade Inspection Robot for Reactor Maintenance
Engineers at Kola NPP (Kolskaya AES) have completed a major upgrade of a robotic crawler used to inspect equipment in high-radiation areas. The enhanced system prevents power cable entanglement and significantly reduces diagnostic time ahead of scheduled maintenance.
Kola NPP is located in the town of Polyarnye Zori in Russia’s Murmansk Region and remains the only nuclear power plant operating above the Arctic Circle. Its power units function in extreme climatic conditions, which demand a tailored approach to technical servicing. Before every maintenance campaign, engineers conduct a detailed inspection of equipment in the reactor building.
To operate in elevated radiation zones, the plant deploys a crawler – a tracked robotic inspection system. The unit moves across hard-to-access areas and is equipped with high-resolution cameras and sensors. It records the condition of metal structures, welded joints and insulation. As a result, personnel do not need to enter hazardous areas, reducing radiation exposure while improving diagnostic quality.
Modernization of the Control System
In February 2026, the plant completed an upgrade of the crawler’s control system. Previously, when the robot followed complex trajectories, its power cable could become entangled. Operators had to manually correct the cable position, extending inspection time and creating a risk of damaging communications. Eliminating this vulnerability became the engineers’ primary objective.
The team developed an original cable winding system with automatic slack compensation. The mechanism responds to trajectory changes and adjusts cable tension in real time. The cable no longer twists or becomes lodged in narrow passages within the reactor building.
Measured Performance Gains
The upgraded crawler now features an improved control console with tactile feedback. The operator feels resistance when the robot encounters an obstacle or when the surface profile changes. This capability enables more precise maneuvering under conditions of limited visibility.
The system also incorporates emergency braking if cable tension exceeds permissible limits. Sensors register critical values within milliseconds and halt movement until the cause is addressed. This approach minimizes the risk of equipment damage or complete loss of the robot inside a high-radiation environment.
The modernization reduced the time required for technical inspection of the reactor building by approximately one third. Previously, the procedure required up to eight hours of continuous operation. It now takes about five hours. This reduction is particularly important given the tight schedule of the maintenance campaign set to begin on March 1, 2026.
Implications for the Nuclear Fleet
Kola NPP became the first nuclear plant in Russia to independently implement the upgraded crawler control system. Station engineers completed the development without external contractors, demonstrating in-house technical expertise and the capacity to solve complex engineering challenges.
The experience can be replicated at other Russian nuclear power plants, particularly those operating older RBMK and VVER reactor series, where regular inspection of hard-to-access areas is mandatory. The crawler upgrade illustrates how targeted technical improvements can enhance nuclear safety.
Engineering for Arctic Conditions
Operating above the Arctic Circle imposes strict technical requirements. The crawler is adapted to temperature fluctuations ranging from minus 40 to plus 40 degrees Celsius, elevated humidity and vibration loads. The modernization accounted for the specific characteristics of the northern site, including reinforced connector seals to protect against condensation.
Kola NPP operates four power units with a total capacity of 1,400 MW. The plant supplies up to 30 percent of Murmansk Region’s electricity demand and remains a critical element of the Northwestern Russian power system.
Robotic systems are becoming an integral component of the nuclear sector’s digital transformation. The crawler upgrade at Kola NPP represents a focused but meaningful step toward fully autonomous diagnostic systems designed to support the long-term safety and reliability of nuclear generation.
