Accessibility and Access Keys 
Skip to Content 
The Chalk River Laboratories (CRL) is located along the west bank of the Ottawa River at Chalk River. The facilities are operated by Atomic Energy Canada Limited, a Crown Corporation. AECL’s major research and development efforts take place at CRL.
The National Research Universal (NRU) reactor has been operating at CRL since 1957. It is the centre for neutron beam research in Canada, is used for materials research, and produces the majority of the world’s supply of critical medical isotopes that are used for diagnosis and treatment of cancer and other illnesses.
The facility discharges various types of wastewaters to the river via eight identified discharge pipes. The outfalls for six of these discharges are located along the banks of the river, while the outfalls for the remaining two are located offshore.
The largest aquatic plume originates from the process sewer. The process sewer carries waste heat from the reactors, contains some residual chlorine from periodic shock chlorination of the reactor cooling water, and may contain small concentrations of radioactive materials. Effluent flow rates through the process sewer average about 83 million litres per day, primarily due to the large volume of NRU coolant. The plume is estimated to extend approximately 1,000 m downstream and 150 m offshore.
Between 1953 and 2000, some liquid wastes were dispersed into 4 pits that were dug into the sandy soil; 2 reactor pits, one chemical pit and one laundry pit. Groundwater monitoring wells near the chemical pit have detected polychlorinated biphenyls (PCBs) and tetrachlorodibenzofurans (TCDFs). Although these pits are no longer active, they remain potential sources of concern.
Contaminants of potential environmental concern from the CRL site include:
Copper, Aluminum, Iron, Ammonium, Phosphorus, Lead, Mercury, Cadmium, Zinc, Cobalt and Cesium.
Physical stressors include thermal releases to the aquatic environment from the cooling water discharge, and entrainment/impingement of aquatic biota from the cooling water intake.
You can download a detailed review of the “Ecological Effects Review”:http://www.aecl.ca/pdfs/EER-Report-Jan05.pdf of Chalk River Laboratories from the AECL website.
Ottawa Riverkeeper is part of the Environmental Stewardship Council working with AECL and other interested parties to ensure the safety of our water”. See the Terms of Reference [word file: 0.13mb] and peruse the AECL website for more information.
Chalk River in the NEWS