AECL has operated research reactors at the Chalk River Laboratories (CRL) site since 1947, for the purpose of nuclear energy and scientific research and for the production of radioisotopes. Over the past 50 years there has been a gradual accumulation of legacy liquid wastes that contain intermediate and high levels of radioactivity. While currently stored in stainless steel tanks and monitored, the wastes cannot be processed in the existing treatment facilities at CRL. The liquid wastes contain radioactive substances (principally cobalt-60, cesium-137, strontium-90 and uranium) and non-radioactive substances (principally mercury, cadmium, acids and bases). The total volume of liquid wastes is about 300 m³.

The Liquid Waste Transfer and Storage (LWTS) Project has been launched at CRL to consolidate the liquid wastes that are stored in 21 tanks, some of which have been in operation for more than 40 years, into a new tank system that meets current standards for design and construction with improved systems for waste sampling and retrieval. The LWTS project will also condition high-level liquid medical isotope production wastes presently stored in a stainless steel double-walled tank. The wastes in this tank will be transferred and conditioned to reduce nuclear criticality constraints and monitoring requirements during storage. The new storage system will consist of storage tanks and equipment in a new stand-alone building. Included in the project are all infrastructure, equipment and systems to retrieve, transfer and condition the liquid wastes and to manage any secondary wastes created from the recovery operations.

The project has entered the detailed design stage for the two key elements, waste storage and waste retrieval and transfer. Technical specifications have been prepared and procurement of these systems is in progress. AECL has completed extensive tank investigation activities including physical inspections, sampling and analyses, leading to preparation of a safety assessment report. An Environmental Assessment with supporting public consultation has been conducted, resulting in a decision of “no significant environmental effects”, granted by the CNSC in 2006 April. The target is to reach operational turnover in 2009. The LWTS Project will be a significant step towards a long-term management solution for CRL liquid high-level radioactive wastes, providing engineered solutions to deal with wastes that were assessed as the highest remediation priority for the CRL site. This project demonstrates AECL’s corporate commitment to minimize legacy liabilities for future generations.