Management and Up Keep of AECL's Prototype Reactors Being Held for Deferred Decomissioning

Abstract

AECL is responsible for three prototype power reactor sites located at Douglas Point on the Bruce Nuclear site, Ontario; Gentilly-1 (G-1) near Bécancour, Québec located on the Gentilly-2 Hydro Quebec site and Nuclear Power Demonstrator (NPD) located at Rolphton, Ontario. Each site has its own unique challenges in maintaining it in a static state. All three sites operate under separate Waste Management Facility Licenses approved by the Atomic Energy Board of Canada (now the Canadian Nuclear Safety Commission).

Decommissioning of a Nuclear Power Reactor Generating Station in Canada is carried out in various stages due to the safety and economic considerations associated with it. An immediate dismantling of plant and equipment following shutdown has not been desirable from the point of view of keeping worker radiation exposure as low as reasonably achievable (ALARA) and is scheduled taking this into consideration. The objectives of safe shutdown activities is to shutdown the reactors, systems and components along with the support buildings and place them in a safe and static state where only systems required for continued monitoring and surveillance activities over a predetermined period would remain operational. NPD, Douglas Point and G-1 sites were safely shutdown following this strategy. Maintaining the safe shutdown state of the active and non active facilities of each site varies as the only common approach used to bring each site to safe shutdown state was the removal of the secondary systems and equipment. From the time a facility is safely shutdown through to decommissioning and remediation of the site, maintenance and monitoring of the site must continue. Configuration management of the site must be maintained for estimating and maintenance purposes. Appropriate budget planning for upgrades, modifications and capital replacements even though the facility is shut down must be completed. Management and upkeep of AECL’s prototype reactors being held for decommissioning presents various challenges. Knowledge transfer, aging facilities that have spent their projected life cycle and records management are underestimated tasks. Maintenance of the facilities, equipment, systems and site must be kept at an appropriate level to meet regulations and keep the facilities in a safe state until decommissioning is completed.

This paper details the ongoing activities required to identify and mitigate risks associated with extended periods of storage with surveillance (SWS). It will also outline how the ongoing longterm program for the sites is being developed to allow key decision points to be made on maintaining the period of SWS and the potential strategies reflecting on the transition into decommissioning, while being cognizant of international decommissioning initiatives.