Re-zoning of Radiological Zones at a Nuclear Power Plant
Following the permanent shutdown of a nuclear power plant, ISR was contracted to develop the process to re-zone portions of the plant site to reduce the radiation protection requirements, operational costs, and the number of control zones. ISR created plans to identify the re-zoning locations and characterized each location based on its radiological risk. Detailed re-zoning plans were then prepared and an in-field radiation survey protocol was developed that was compliant with regulatory requirements and international best practices, such as the Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM).
ISR prepared a plan to identify all locations (rooms and buildings) that could be rezoned, along with the steps and actions needed to realize this rezoning process. ISR prepared a list of buildings and rooms and studied the radiological historical review to initially categorize the rooms based on their radiological risk. A preliminary site investigation was performed to confirm the actual state of the rooms and revise the initial categorization. A plan was prepared outlining the process by which rezoning could proceed.
Detailed rezoning plans, including step-by-step administrative actions and technical specifications, were prepared as part of a second project phase. A protocol was developed for the measurements to be taken in the field that were used to demonstrate compliance with both power plant requirements and Canadian Nuclear Safety Commission (CNSC) expectations. Moreover, this protocol was also aligned with such international best practices as those delineated by the Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM), the United States Environmental Protection Agency, Nuclear Regulatory Commission, Department of National Defence, and Department of Energy.