Robot developed for Loviisa steam generator work

The inspection and cleaning of Loviisa's steam generators is currently carried out every four years manually by people. The work is performed in a challenging environment and involves occupational safety risks. The relatively high radiation levels inside the steam generators add to the challenge of the work.

"We started the project by mapping the possible alternatives for cleaning and inspecting steam generators," said Fortum Development Manager Ville Lestinen. "However, none of the existing alternatives were completely suitable for this purpose, so we decided to start collaborating with JAMK on the development of a robot that would be suitable for these tasks."

The design, development and factory tests related to the equipment were performed by JAMK in Jyväskylä. Fortum employees headed the project and brought the steam generator cleaning and inspection process expertise. The design work started in 2019, and the equipment was piloted in September 2020 in the annual outage of Loviisa unit 1.

"After many ideas, we ended up developing a robotic raft that carries the equipment needed in the maintenance," said Senior Lecturer Jaakko Oksanen, a project manager working at JAMK. "The complex structure of the inspection site and the very high safety requirements significantly increased the challenge level of the project."

During the project, modifications to the structures were made based on the tests performed at the Jyväskylä swimming pool. The goals and requirements set by Fortum were ultimately achieved through numerous material and equipment optimisations.

Following the tests performed in the swimming pool environment, the raft was piloted at the Loviisa power plant.

“Taking images of the upper parts of the steam generator was very successful, and inspecting the condition of the structures also went fine," said Lestinen. "The raft's control systems operated as expected, and it was easy to manoeuvre the raft to the desired locations. In the further development phase, the focus will be on optimising the equipment's shape and improving the ability to bypass the complex structures inside the steam generator."

Further development of the robot is already under way to get an improved raft ready for deployment in the next inspections of Loviisa's steam generators in 2022.