For more than a decade, unmanned robots have been used to detect and dispose of bombs in war zones and to assist with recovery efforts in disaster areas. Since last March, they have been utilized to help clean up the reactors at the Fukushima Daiichi nuclear power plant in Japan. Here in the United States, nuclear energy facilities are also beginning to introduce this technology to help keep workers out of areas where there may be elevated radiation levels. Leading the effort is the radiation protection team at Duke Energy’s Robinson Nuclear Plant in Hartsville, S.C., where robots conduct inspections and perform maintenance activities inside the facility, limiting worker exposure to radiation.
“Early last year, we set the vision that we wanted our radiation protection group to be the best in the industry and we saw this as one of the critical tools for us,” said Daren Cato, a radiation protection technician at Robinson who spearheaded the effort to bring robots to the facility. “We were impressed by what we saw at Fukushima, but it was also important to conduct a thorough selection process to ensure that chose the right robots for our facility,” Cato said.
After testing several different robots, Cato and his team decided to order two 510 PackBot robots and one 710 Warrior from Massachusetts-based iRobot. The lightweight, versatile PackBot is used for tactical operations, such as inspecting objects, whereas the Warrior performs heavy-duty tasks, such as removing and replacing filters in the high integrity containers located in the facility’s four radioactive waste bunkers. Both the PackBot and Warrior have assisted with the recovery efforts at Fukushima and their success with these activities helped solidify the team’s decision.
“The PackBot and Warrior are designed for robust missions, primarily military missions,” said Tim Trainer, interim general manager of iRobot’s Defense & Security business unit. “That provides them the strength, reliability and maneuverability that make them useful in all industrial markets, including the nuclear energy industry.”
The robots, originally built for the battlefield, required only a few modifications before being dispatched to the Robinson nuclear energy facility. According to Trainer, the main adjustment involved equipping the robots so that they could be used in areas of the facility that block radio signals. In order to avoid communications issues, iRobot engineers outfitted the Warrior and PackBots with fiber spoolers that allow operators to control them via a fiber optic tether instead of radio frequency.
The radiation protection team at Robinson chose the iRobot products primarily because they are easy to use, Cato said. “They have a video-game style control system, so the learning curve isn’t steep,” he said. “They are so user-friendly that an intern learned to use the robot proficiently by himself in about five minutes.”
Two technicians are currently qualified to operate the robots, and the facility’s entire radiation protection department, which consists of about 20 employees, will be trained to use the technology over the next few months. The training process typically takes five days to complete. In order to become qualified, the employee must prove that he or she can use the robot for dexterous tasks, such as picking a 15-millimeter watch battery up from the floor, and must be able to recite from memory the areas of the plant where they can and cannot be used due to radio interference issues in certain buildings.
“The goal is to get as many people qualified to operate the robots as we can and to drive a paradigm shift within our department so that our entire team is constantly looking for new opportunities to use this technology,” said Cato.
Among other uses, the PackBots are often used to carry out visual inspections in areas of the facility with elevated radiation levels, significantly limiting worker exposure and allowing the task to be carried out thoroughly. While radiation is strictly controlled and monitored at all nuclear energy facilities, plants like Robinson have invested in robotic technology to further protect their employees.
“If we were to send a person into a high radiation area, we would want them to do the inspection as quickly as possible,” Cato explained, noting that all employees are strictly monitored to ensure minimal health risks. “With the robotics, however, we can control the machines from a safe distance and take all the time we need to carry out the task.”
Robinson is the first U.S. nuclear energy facility to use iRobot’s machines, but it will not be the last. Brunswick Nuclear Plant, also owned by Duke Energy, has also ordered a PackBot for use at their facility, and Cato and his team recently gave a presentation about the benefits of using robots to 30 radiation protection managers from nuclear plants across the country.
“We encouraged our colleagues at Brunswick to go through their own selection process to ensure that the iRobot machines could meet their facility’s specific set of needs, and they came to the same conclusion,” Cato said. “I look forward to sharing best practices and information related to the robots with my counterparts at Brunswick and across the industry as this technology becomes more widespread.”