Management of Waste following a Historical Accident

Abstract

In December of 1952, Canada’s National Research Experimental Reactor (NRX) located at Canadian Nuclear Laboratories (CNL) Chalk River site (formerly Atomic Energy of Canada Limited (AECL)) experienced a runaway reaction caused from a series of human error events resulting in a partial meltdown of the fuel in the reactor calandria. Clean up response to the event involved dispersion of nearly five million liters of radioactive wastewater to engineered dispersal pits located in Chalk River’s designated Waste Management Area. In addition, removal of the failed fuel rods, damaged calandria, as well as decontamination of several areas of the reactor building were required to repair the reactor and return the system to operation. These actions resulted in the generation of varying levels of solid radioactive wastes that were interred in sand trenches in the site’s designated waste management area.

Environmental Protection and Waste Management teams were originally engaged in managing the impact of this historical waste on the environment through controlled operation, the implementation of robust environmental monitoring systems, and engineered barrier systems to mitigate the migration of contaminants. Later, several initiatives were undertaken to characterize, retrieve and relocate spent and failed fuel rods to a secure location that are now safely stored according to current standards and regulations.

As CNL looks towards future remediation of the Waste Management Area, including modern storage and disposal options with the development of a Near Surface Disposal Facility; a collaborative, cross- functional team comprised of Environmental Remediation Specialists, Reactor Segmentation, Waste Characterization, Radiation Protection, and Waste Management Operations is undertaking environmental site assessments. These will be utilized to identify areas that require remediation, delineate low level waste from intermediate level waste and is capitalizing on the unique opportunity to access and characterize a reactor calandria using unique tooling.