Wednesday, May 19, 2021

Can Drones Be Used to Eliminate Worker Radiation Exposure For Certain Tasks in Nuclear Plants?

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At Peach Bottom Nuclear Plant, EPRI and Exelon Demonstrate Drone that Surveys for Radiation and Inspects Components Autonomously

EPRI and Exelon successfully demonstrated the use of an autonomous drone to map radiation levels and inspect equipment in a nuclear plant—one of the first such demonstrations in the U.S. nuclear power industry. The tests took place at Peach Bottom Atomic Power Station’s Unit 1, which has been inoperable since 1974, as well as a Peach Bottom facility used to store low-level radioactive waste. Unit 1 has equipment and tight spaces similar to those in operating nuclear plants, making the demonstration an important first step to deploying autonomous drones in the nuclear power industry. RADeCO Inc. provided the radiation detection instruments for the demonstration, and Exyn Technologies provided the autonomous drone navigation system.

Radiation surveys, equipment inspections, and other tasks can expose nuclear plant workers to elevated radiation. Drones offer the potential to complete these tasks autonomously, reducing exposure to radiation and other industrial hazards. Prior use of drones in nuclear plants has relied on manual operation, which can be difficult in tight spaces and requires line of sight between the operator and drone—often resulting in radiation exposure. For safe navigation during this early-stage demonstration, the Exyn drone automatically maintained a 3-foot buffer around it. For future demonstrations and deployments, this buffer can be adjusted based on operating experience and location of sensitive equipment.

The team made software and hardware changes to connect the radiation detectors with the drone and navigation system. Using laser-based light imaging detection and radar (LIDAR) technology, the drone created high-resolution 3D maps of several areas inside Unit 1 and the low-level waste facility. Using a base station tablet, participants programmed the drone’s flight plans onto these maps. As it flew to various locations, the radiation detectors collected readings every three seconds, displaying the results on the 3D maps.

A video camera simulated the inspection of various components. Electric heated blankets were wrapped around pipes, and the drone’s infrared camera detected the elevated temperatures. To test the drone’s ability to avoid obstacles, a worker walked in its path. The drone immediately detected the worker, safely flew around him, and returned to its programmed route.

“I’m very impressed with this technology,” said Peach Bottom’s Senior Instrument Physicist Richard Bolding. “It’s so user-friendly. It took me three minutes to set a destination and return path for the drone. This can greatly reduce the learning curve compared to the manual drone technology we presently use.”

Researchers also deployed the 3D mapping system, radiation detectors, and cameras on a manually operated ground vehicle, which completed a similar set of tasks in Peach Bottom’s operating units (2 and 3).

“This project showed that drones can potentially replace people for certain tasks in nuclear plants, eliminating worker radiation exposure for those tasks,” said Phung Tran, an EPRI expert on radiation safety in nuclear plants.

The Peach Bottom demonstration is part of EPRI’s Next Generation Radiation Protection (NextGen RP) initiative, which is examining various ways to streamline radiation protection and reduce worker radiation exposure. This drone is one of a suite of technologies under investigation as part of broader plant modernization in the nuclear power industry.

While the drone successfully completed all tasks at Peach Bottom, the demonstration pointed to areas for improvement. For instance, the team used a large drone to accommodate a heavy payload, restricting access in tight spaces. The drone’s powerful propellers stirred up dust in some areas, raising the concern that it could potentially spread contaminated materials in certain applications. Future deployments may consider the use of smaller, less powerful drones.

Key EPRI Technical Experts:

Richard McGrath, Phung Tran
For more information, contact techexpert@eprijournal.com.

Photo of drone at top of article courtesy of RADeCo Inc.


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