Challenges in updating a generic safety analysis report after 22 years of technological and regulatory progress

Full text: The original Safety Analysis Report (SAR) for the 20 kW (nominal) Ecole Polytechnique SLOWPOKE research reactor comprised a generic report produced in 1977. This SAR was applicable to all SLOWPOKE reactors constructed in the period from 1971 to 1985. Since that period IAEA international standards for SARs have changed and been developed into Safety Series 35-G1, Safety Assessment of Research Reactors and Preparation of the Safety Analysis Report. 35- G1 is one of the IAEA (green cover) Safety Guides, intended to be recommendations based on international experience. In addition national licensing standards for research reactors have become more rigorous since the original generic SAR was produced. The original SLOWPOKE reactor was designed to operate for 20 years and was not intended to be refueled. After 21 years of operation with the original HEU fuel core, it was planned to convert the Ecole Polytechnique reactor core to LEU fuel in order to extend the life of the reactor for another 30 years. Since this was the first SLOWPOKE reactor to be converted to LEU fuel, preparation of an updated and site-specific SAR was necessary to obtain authorization for refueling. The reactor was successfully refueled and relicensed with LEU fuel, based on the updated reactor specific SAR, which closely followed the SS-35-G1 recommendations. The original Ecole Polytechnique SLOWPOKE reactor generic SAR was used to license this reactor for first criticality in May 1976, as well as to license seven other SLOWPOKE reactors in Canada and one in Jamaica. When the original SAR was issued, no site-specific information was incorporated into the SAR. Site-specific safety and licensing issues were historically addressed to the regulator in other documentation, outside the generic SAR. By contrast, the updated SAR discusses or directly references other documentation, where appropriate, for all site-specific issues. In addition to following the recommendations of 35-G1, the following major tasks also provided important information for the SAR production: review of historical experience of SLOWPOKE reactors (124 reactor-years); from annual safety reviews; development of LEU core transient analysis for comparison with required commissioning transients; operational safety review (OSR) of the reactor installation; independent review of LEU core commissioning procedures; and verification of analysis predictions with commissioning results and incorporation into the SAR. (author)