DS397 Saf Use Mod RRs with NUSSC comments 18-06-2010

Radiation protection 144.8. A utilization or modification should not significantly affect the overall radiationprotection programme for the research reactor facility, particularly where doses have alreadybeen reduced to levels that are as low as reasonably achievable (optimization principle). Theoriginal design will typically have been based on a combination of shielding, ventilationfiltration and decay to reduce radioactive releases, with associated monitoring instrumentationfor radiation and airborne radioactive materials, and for all operational states and accidentconditions. If the experiment or modification would otherwise affect the overall radiationprotection measures, then additional measures may be necessary to reduce the dose topersonnel during the installation of the project, operation, handling and dismantling of anexperiment, or the implementation of a modification project. These measures may include theremoval of sources of high radiation, the provision of additional shielding and/or theprovision of remote handling devices.4.9. If the failure of the experimental device or the modified system could lead todegradation of either the original system or the additional system of barriers to the release ofradioactive materials, the effects of such an accident should be considered in the design.4.10. The potential for an uncontrolled release of radioactive materials should be limitedand the amounts of such material released should be minimized by measures such as the useof delay tanks, filters or recirculation. This applies for all stages of the project, including theinstallation phase, normal operation, removal, storage and shipment of experimental devicesor modified systems.Safety devices4.11. Whenever possible, experiments and modifications should be designed to minimizethe need for active safety devices (e.g. by the use of inherent safety features, passive systemsand fail safe design).4.12. If safety devices are interconnected with the reactor protection system, they should bedesigned so as to maintain the quality and effectiveness of the reactor protection system. Thepossibility of deleterious interactions with the reactor protection system should be assessed.4.13. If an experiment might create a hazard to the reactor or to personnel, the protectionand control system of the experiment should be connected to the reactor systems in order to14 The basic safety standards for radiation protection can be found in Ref. [19]17