Coupling interests in small modular reactors (SMR) as efficient and effective method to meet increasing energy demands with a growing aversion to cost and schedule overruns traditionally associated with the current fleet of commercial nuclear power plants (NPP), SMRs are attractive because they offer a significant relative cost reduction to current-generation nuclear reactors—increasing their appeal around the globe. Sandia's Global Nuclear Assurance and Security (GNAS) research perspective reframes the discussion around the "complex risk" of SMRs to address interdependencies between safety, safeguards, and security. This systems study provides technically rigorous analysis of the safety, safeguards, and security risks of SMR technologies. The aim of this research is three-fold. The first aim is to provide analytical evidence to support safety, safeguards, and security claims related to SMRs (Study Report Volume I). Second, this study aims to introduce a systems-theoretic approach for exploring interdependencies between the technical evaluations (Study Report Volume II). The third aim is to demonstrate Sandia's capability for timely, rigorous, and technical analysis to support emerging complex GNAS mission objectives.
This study examines methods that can help maximize confidence in maintaining Continuity of Knowledge (CoK) on plutonium-bearing wastes, from a final safeguards-verification measurement through emplacement underground. The study identifies Containment and Surveillance (C/S) measures that can be applied during packaging of plutonium wastes at the Savannah River Site (SRS) in South Carolina, USA, through shipment to, and receipt and disposal at the Waste Isolation Pilot Plant (WIPP) near Carlsbad, New Mexico, USA. Results of this study could apply to countries with a Comprehensive Safeguards Agreement (CSA) that plan to dispose in a geological repository plutonium or other non-fuel nuclear materials that are under international safeguards.
Current designs for spent fuel transportation casks cannot ensure a cask's integrity during shipment, nor is there any verifiable means of maintaining continuity of knowledge (CoK) on a cask's contents. Spent fuel destined for encapsulation plants or geological repositories requires additional containment and surveillance (C/S) measures during shipment. Following final safeguards accountancy measurements on spent fuel assemblies, the shipment of verified assemblies will require unprecedented reliance on maintaining CoK on the fuel inside transport casks. Such increased reliance is due to the lack of reverification of spent fuel following encapsulation into disposal canisters and by meeting the requirement of dual C/S measures during such fuel shipments according to recommendations made by the Application of Safeguards to Geological Repositories (ASTOR) International Atomic Energy Agency (IAEA) expert group. By designing spent fuel transportation casks with effective seals integrated into their design, CoK can be more effectively maintained than by ad hoc C/S measures because seal integration ensures that a cask has not been tampered with. Externally applied seals might not be able to provide such assurance for currently designed spent fuel transportation casks, although some combination of seals, detectors, and/or a technology that can verify canister integrity might provide this assurance. This paper examines the design criteria for integrating safeguards seals into transportation casks and provides recommendations for near-term applications.
Once a geological repository has begun operations, the encapsulation and disposal of spent fuel will be performed as a continuous, industrial-scale series of processes, during which time safeguards seals will be applied to transportation casks before shipment from an encapsulation plant, and then verified and removed following receipt at the repository. These operations will occur approximately daily during several decades of Sweden's repository operation; however, requiring safeguards inspectors to perform the application, verification, and removal of every seal would be an onerous burden on International Atomic Energy Agency's (IAEA's) resources. Current IAEA practice includes allowing operators to either apply seals or remove them, but not both, so the daily task of either applying or verifying and removing would still require continuous presence of IAEA inspectors at one site at least. Of special importance is the inability to re-verify cask or canisters from which seals have been removed and the canisters emplaced underground. Successfully designing seals that can be applied, verified and removed by an operator with IAEA approval could impact more than repository shipments, but other applications as well, potentially reducing inspector burdens for a wide range of such duties.
Deep borehole disposal (DBD) has been suggested as an option for disposing spent nuclear fuel in a number of countries, including several countries that are subject to international safeguards. DBD presents some distinct challenges for safeguards compared to a conventional mined geological repository (MGR), including the ability to verify declared design information about the borehole. The ability to verify a borehole's design is crucial for assuring that spent fuel or other accountable nuclear materials are disposed as declared in a borehole of known and verifiable design. This study reviews existing commercial off-the-shelf (COTS) borehole inspection tools currently used by the drilling industry, and evaluates the capabilities of those COTS inspection tools against how well they can meet potential needs and requirements of Design Information Verification (DIV) inspections for international safeguards. The study provides recommendations for several promising COTS borehole inspection tools that might be used for DIV safeguards inspections and recommends possible modifications and future testing
In 2017, four U.S. National Laboratories collaborated on behalf of DOE/NNSA to explore the safeguards knowledge retention problem, identify possible approaches, and develop a strategy to address it. The one-year effort consisted of four primary tasks. First, the project sought to identify critical safeguards information at risk of loss. Second, a survey and workshop were conducted to assess nine U.S. National Laboratories' efforts to determine current safeguards knowledge retention practices and challenges, and identify best practices. Third, specific tools were developed to identify and predict critical safeguards knowledge gaps and how best to recruit in order to fill those gaps. Finally, based on findings from the first three tasks and research on other organizational approaches to address similar issues, a strategy was developed on potential knowledge retention methods, customized HR policies, and best practices that could be implemented across the National Laboratory Complex.