Crl Site Transition: Safe Shutdown and Readiness for Decommissioning of National Research Universal and Mo-99 Production Facility

Abstract

On 2015 February 06, the Government of Canada announced that Canadian Nuclear Laboratories (CNL) will operate the National Research Universal (NRU) Reactor until 2018 March 31. At the conclusion of this period, the Reactor will be placed in a state of storage with surveillance until decommissioning. Since 2016 October, the Mo-99 Production Facility (MPF) is in a stand-by mode with the ability to produce Mo-99, if needed, until the NRU Reactor is permanently shut down. As part of CNL’s vision, the Chalk River site is being revitalized. This work involves the decommissioning of older facilities in order to make room for modern research facilities. The turnover of nuclear facilities from an operating state to active decommissioning needs to be documented and managed to ensure Health, Safety, Security and Environmental (HSSE) risks are identified, and eliminated or effectively controlled. Regulatory requirements are driven by G-219, Decommissioning Planning for Licensed Activities, and N294-09, Decommissioning of Facilities Containing Nuclear Substances. Additional site-specific clarifications are contained in a Licence Condition Handbook. This paper will outline CNL’s process to attain readiness for the safe shutdown of NRU and MPF, and to enable the transfer of these facilities from Operations to Decommissioning. The safe shutdown activities include the revision of Operating procedures for new facility states, as well as the preparation of supplementary safety case documentation for transition and post-shutdown states. Major milestones in the NRU Shutdown Plan include preparing the safety case for the fuel rod bays, the defueling of the reactor, and the drainage of the reactor vessel. Major milestones for safe shutdown of MPF include the removal of processing equipment, decontamination of the hot cells, and shutdown of active ventilation. The Canadian Government’s commitment for the repatriation of Highly Enriched Material back to the United States also relates to the shutdown of NRU and MPF. Documentation required for the turnover of permanently shut down facilities to the Decommissioning authority includes well-defined facility boundaries, plant configuration, and remaining radiation and environmental hazards. It must identify which components continue to perform a safety function, for the planning and execution of decommissioning activities. The transfer certificate confirms the shut-down state, identifies remaining hazards, and formally transfers the responsibility for the maintenance, care, control and security of a facility from Operations to Facilities Decommissioning.