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For several years, Pacific Northwest National Laboratory (PNNL) has been assessing the reliability of nuclear fuel supply in support of the U.S. Department of Energy/National Nuclear Security Administration. Three international low enriched uranium (LEU) reserves, which are intended back up the existing and well-functioning nuclear fuel market, are currently moving toward implementation. These backup reserves are intended to contribute to the provision of credible assurance of the uninterrupted supply of LEU to countries to operate their nuclear power reactors in the event that their primary fuel supply is disrupted, whether for political or other reasons. The efficacy of these backup reserves, however, may be constrained without redundant fabrication services. This report presents the findings of a recent PNNL study that simulated outages of varying durations at specific nuclear fuel fabrication plants. The modeling specifically enabled prediction and visualization of the reactors affected and the degree of fuel delivery delay. The results thus provide insight on the extent of vulnerability to nuclear fuel supply disruption at the level of individual fabrication plants, reactors, and countries. The simulation studies demonstrate that, when a reasonable set of qualification criteria are applied, existing fabrication plants are technically qualified to provide backup fabrication services to the great majority of the world's power reactors. Fewer than 10 percent of existing nuclear power reactors cannot be inferred to have technically qualified backup fabrication sources. The report concludes with an assessment of the redundancy of fuel supply in the nuclear fuel market, and a description of potential extra-market mechanisms to enhance the security of fuel supply in cases where it may be warranted. This report is an assessment of the ability of the existing market to respond to supply disruptions that occur for technical reasons. A forthcoming report will address political disruption scenarios.

Conventional probabilistic risk assessments (PRAs) are not well-suited to addressing long-term reactor operations. Since passive structures, systems and components are among those for which refurbishment or replacement can be least practical, they might be expected to contribute increasingly to risk in an aging plant. Yet, passives receive limited treatment in PRAs. Furthermore, PRAs produce only snapshots of risk based on the assumption of time-independent component failure rates. This assumption is unlikely to be valid in aging systems. The treatment of aging passive components in PRA does present challenges. First, service data required to quantify component reliability models are sparse, and this problem is exacerbated by the greater data demands of age-dependent reliability models. A compounding factor is that there can be numerous potential degradation mechanisms associated with the materials, design, and operating environment of a given component. This deepens the data problem since the risk-informed management of materials degradation and component aging will demand an understanding of the long-term risk significance of individual degradation mechanisms. In this paper we describe a Bayesian methodology that integrates the metrics of materials degradation susceptibility being developed under the Nuclear Regulatory Commission’s Proactive Materials Degradation Assessment Program with available plant service data to estimate age-dependent passive component reliabilities. Integration of these models into conventional PRA will provide a basis for materials degradation management informed by the predicted long-term operational risk.

Federal agencies are required by law to install energy meters and conduct energy and water evaluations at their facilities. Per Section 103 of the Energy Policy Act of 2005, agencies are required to collect at least hourly energy data, incorporate metered energy data into data management systems, and provide the data to energy managers. Comprehensive energy and water evaluations of federal facilities are required by Section 432 of the Energy Independence and Security Act of 2007, which states that "covered facilities" which constitute at least 75 percent of facility energy use at each agency must be evaluated every 4 years for cost-effective energy and water savings opportunities. Energy and water metered data can help energy managers make informed operations and investment decisions throughout the energy and water evaluation process. Metered data can be used to identify the facilities with the highest energy use, benchmark facility performance, track facility energy and water use, set energy and water use goals, and prioritize facility investments. Acronyms and Abbreviations BCS Building control system CBECS Commercial Building Energy Consumption Survey CDD Cooling degree-day EWCMs Energy and water conservation measures EISA Energy Independence and Security Act of 2007

Previous PNNL work has shown the existing nuclear fuel markets to provide a high degree of supply security, including the ability to respond to supply disruptions that occur for technical and non-technical reasons. 1 It is in the context of new reactor designsthat is, reactors likely to be licensed and market ready over the next several decadesthat fuel supply security is most relevant. Whereas the fuel design and fabrication technology for existing reactors are well known, the construction of a new set of reactors could stress the ability of the existing market to provide adequate supply redundancy. This study shows this is unlikely to occur for at least thirty years, as most reactors likely to be built in the next three decades will be evolutions of current designs, with similar fuel designs to existing reactors.