URL Closure: What It Takes To Decommission An Underground Research Facility

Abstract

Atomic Energy of Canada Limited's (AECL) Underground Research Laboratory (URL) was built to provide a facility where concepts for long-term management of Canada's nuclear fuel waste in a deep geological repository could be studied. Construction of the URL began in 1982 with completion of the construction phase in 1990 followed by the experimental phase.

In 2003 a decision was made to discontinue operation of AECL's URL and ultimately decommission and permanently close the underground portion of this facility. Following the completion of a number of underground experiments, closure activities commenced in 2005. Decommissioning was managed and planned by AECL with support from J.S. Redpath Ltd., a mining contractor who had provided long term construction and operations support to the URL. From 2006, the URL decommissioning was funded under the Nuclear Legacy Liability Program (NLLP), through Natural Resources Canada (NRCan). All underground-related closure activities were completed in late 2010.

As part of a carefully planned decommissioning process, a comprehensive closure plan was developed and submitted to the Manitoba Provincial government for approval in 2006. The closure plan included the decommissioning of all surface and underground boreholes and the safe removal of all underground infrastructure and equipment where technically and economically feasible to do so. Surface and underground boreholes were decommissioned and grouted to limit the upwards migration of deep, saline groundwater at the site. The final stage of closure was sealing the access and ventilation shafts with concrete caps.

Decommissioning an underground facility to the extent and completeness the URL was decommissioned has never been undertaken in Canada before now. Extensive planning and the development of unique methodology and equipment were keys to the success of the project.