The Bowser Room in its final stages of remediation
Canadian Nuclear Laboratories’ (CNL) Facilities Decommissioning team recently implemented a novel remote strategy to remove approximately 10,000 kilograms (kgs) worth of tanks and components from the historic Bowser Room at Chalk River Laboratories – alleviating high radiological hazards from the area. With this project, the team took a holistic approach and used advanced work methodology to significantly reduce the risk of radiation exposure to staff, prioritizing safety while upholding efficiency and efficacy.
Given its name because of its original unique colour – similar to that of the famed Super Mario character – the Bowser Room was built in the 1950s as part of Chalk River Laboratories’ reactor support facilities for the National Research eXperimental (NRX) reactor and the National Research Universal (NRU) reactor. The Bowser Room, located in the basement of an NRX support facility, was where rod bay water for NRX was filtered.
Legacy photos of the Bowser Room during its active use
The Bowser Room originally featured a single entrance that also functioned as the sole exit, further complicated by a stairwell within this entry/exit point. Due to the volume of the high radiological hazards in the room, the configuration of the stairwell presented a significant challenge. With only one route available for waste removal, the risk was that staff would face radiation exposure during the removal process. As one of the core principles in the nuclear industry is to keep all radiation exposure “as low as reasonably achievable”, the team needed to find a solution to reduce risk while conducting the Bowser Room’s remediation.
The Bowser Room before the waste removal process began
To mitigate the hazard, the integrated planning team collaborated with CNL’s onsite experts to develop a remote work approach. This approach prioritized personnel safety by minimizing radiation exposure. The key components of the remote work approach were:
The active drain line removal and the sea container lay-down area
Remote Processing and Removal: the waste was processed and removed remotely, eliminating the need for staff to enter the Bowser Room and thereby virtually eliminating any accumulated radiation dose.
Sea Container Room Addition: the integrated planning team proposed placing sea containers outside the Bowser Room to create an extension of the room. This allowed access directly into the basement from the exterior and provided a simple and contained waste loading, packaging, sealing, and removal pathway for the highly contaminated components of the Bowser Room’s structures, systems, and components.
Fully Equipped Sea Containers: each sea container was comprehensively equipped and seamlessly integrated into the building’s infrastructure. All sea containers adhered to CNL occupancy standards, including fire detection systems and building codes. Additionally, they were outfitted with High-Efficiency Particulate Air (HEPA) filtration units to ensure proper ventilation.
Remote-Controlled BROKK Robot: weighing over 900 kgs, the BROKK robot is a remotely operated device adept at navigating confined spaces and comes equipped with grapples, a concrete hammer, and nibblers for versatile operation.
The coring of the access door into the Bowser Room
The project began the waste removal process in early 2023, equipping the Bowser Room with a standalone ventilation unit to incorporate HEPA filtration, which effectively captured all airborne contamination generated during the fieldwork. Additionally, the room featured a legacy sump pit, which served as the designated collection point for residual liquid waste throughout the removal activities. To effectively manage the residual liquid waste, spill control and containment measures were strategically placed to channel the liquid waste into the sump pit. Once the team completed this work, the contents of the sump pit were sampled, characterized, and packaged per CNL’s waste management procedures.
Waste removal using the Brokk Robot in 2023
With all waste removed, the project ensured the room was thoroughly cleaned, and applied a fixative to all surfaces to immobilize and seal any residual radiological contamination in place. Subsequently, CNL was able to downgrade the radiological zoning levels.
An empty room in B204 being sprayed and the blue fixative being applied
