SAFEGUARDS MOTIVATIONS AND LIMITATIONS ON PYROPROCESSING ACTIVITIES

Electrorefining used nuclear fuel is of key importance for enabling a potential future partitioning and transmutation fuel cycle including fast reactors. Because uranium and plutonium are not completely separated by the refining process and criticality concerns are reduced when using molten salts as the process fluid, some consider pyroprocessing attractive from nonproliferation and safety perspectives. The substantial removal of the very long lived isotopes from the nuclear waste provided by pyroprocessing has motivated the ROK to move forward with research focused on alleviating the strains placed on their saturated storage locations. But even with the experience gained to date on pilot scale operations, there is a lack of a consensus strategy for safeguards. Placement of safeguards technologies into the harsh environment of pyroprocessing will depend on if the technologies can be engineered to withstand the sampling conditions and maintain the necessary uncertainty to meet regulations. Limitations to the expected safeguards coverage under proposed plans are discussed herein. Some researchers proposed safeguards strategies for pyroprocessing plants rely on the Pu/Cm inseparability argument to indirectly verify the plutonium in the process. This approach may lead to significantly underestimating the amount of plutonium present in the transuranic product. Current expectations to administer safeguards are based on gross neutron counting, accounting only for inputs and outputs from the electrorefiner. But neutron counting cannot distinguish between different neutron-emitting elements making it possible to deceive, thus there is inefficiency in plutonium monitoring depending on neutron counting. In order for proposed safeguards plans to minimize reliance on lengthy off-site destructive analysis, other possibilities that preferentially directly verify fissile material need to be researched and developed.