We describe the status of our effort to realize a first neutrino factory and the progress made in understanding the problems associated with the collection and cooling of muons towards that end. We summarize the physics that can be done with neutrino factories as well as with intense cold beams of muons. The physics potential of muon colliders is reviewed, both as Higgs factories and compact highenergy lepton colliders. The status and time scale of our research and development effort is reviewed as well as the latest designs in cooling channels including the promise of ring coolers in achieving longitudinal and transverse cooling simultaneously. We detail the efforts being made to mount an international cooling experiment to demonstrate the ionization cooling of muons.

In the aftermath of Fukushima, a focus of the DOE-NE Advanced Fuels Campaign has been the development of advanced nuclear fuel and cladding options with the potential for improved performance in an accident. Uranium dioxide (UO 2) fuels with various advanced cladding materials were analyzed to provide a reference for cladding performance impacts. For advanced cladding options with UO 2 fuel, most of the cladding materials have some reactivity and discharge burn-up penalty (in GWd/t). Silicon carbide is one exception in that the reactor physics performance is predicted to be very similar to zirconium alloy cladding. Most candidate claddings performed similar to UO 2-Zr fuel-cladding in terms of safety coefficients. The clear exception is that Mobased materials were identified as potentially challenging from a reactor physics perspective due to high resonance absorption. This paper also includes evaluation of UN-U 3 Si 5 fuels with Kanthal AF or APMT cladding. The objective of the U 3 Si 5 phase in the UN-U 3 Si 5 fuel concept is to shield the nitride phase from water. It was shown that UN-U 3 Si 5 fuels with Kanthal AF or APMT cladding have similar reactor physics and fuel management performance over a wide parameter space of phase fractions when compared to UO 2-Zr fuel-cladding. There will be a marginal penalty in discharge burnup (in GWd/t) and the sensitivity to 14 N content in UN ceramic composites is high. Analysis of the rim effect due to self-shielding in the fuel shows that the UN-based ceramic fuels are not expected to have significantly different relative burn-up distributions at discharge relative to the UO 2 reference fuel. However, the overall harder spectrum in the UN ceramic composite fuels increases transuranic build-up, which will increase long-term activity in a once-thru fuel cycle but is expected to be a significant advantage in a fuel cycle with continuous recycling of transuranic material. It is recognized that the fuel and cladding properties assumed in these assessments are preliminary, and that additional data are necessary for these materials, most significantly under irradiation. After the Fukushima accident, a major focus of the AFC has been on fuels with enhanced accident tolerance, a.k.a. "Accident Tolerant Fuels (ATF)". The key objectives that an attractive and viable ATF must satisfy include: • "First do no harm" → at least comparable performance under all conditions, and improved performance in accident scenarios

The Technology Readiness Level (TRL) process is used to quantitatively assess the maturity of a given technology. The TRL process has been developed and successfully used by the Department of Defense (DOD) for development and deployment of new technology and systems for defense applications. In addition, NASA has also successfully used the TRL process to develop and deploy new systems for space applications.Advanced nuclear fuels and materials development is a critical technology needed for closing the nuclear fuel cycle. Because the deployment of a new nuclear fuel forms requires a lengthy and expensive research, development, and demonstration program, applying the TRL concept to the advanced fuel development program is very useful as a management and tracking tool. This report provides definition of the technology readiness level assessment process as defined for use in assessing nuclear fuel technology development for the Advanced Fuel Campaign (AFC).

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The safe, reliable, and economic operation of the nation's nuclear power reactor fleet has always been a top priority for the nuclear industry. Continual improvement of technology, including advanced materials and nuclear fuels, remains central to the industry's success. Enhancing the accident tolerance of light water reactors (LWRs) became a topic of serious discussion following the 2011 Great East Japan Earthquake, resulting tsunami, and subsequent damage to the Fukushima Daiichi nuclear power plant complex. The overall goal for the development of accident-tolerant fuel (ATF) for LWRs is to identify alternative fuel system technologies to further enhance the safety, competitiveness, and economics of commercial nuclear power. Designed for use in the current fleet of commercial LWRs or in reactor concepts with design certifications (GEN-IIIϩ), fuels with enhanced accident tolerance would endure loss of active cooling in the reactor core for a considerably longer period of time than the current fuel system while maintaining or improving performance during normal operations. The complex multiphysics behavior of LWR nuclear fuel in the integrated reactor system makes defining specific material or design improvements difficult; as such, establishing desirable performance attributes is critical in guiding the design and development of fuels and cladding with enhanced accident tolerance. Research and development of ATF in the United States is conducted under the U.S. Department of Energy (DOE) Fuel Cycle Research and Development Advanced Fuels Campaign. The DOE is sponsoring multiple teams to develop ATF concepts within multiple national laboratories, universities, and the nuclear industry. Concepts under investigation offer both evolutionary and revolutionary changes to the current nuclear fuel system. This paper summarizes the technical evaluation methodology proposed in the United States to aid in the optimization and prioritization of candidate ATF designs.

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SUMMARYThe AFCI Options Study has examined the issues with the current use of nuclear power and collected and summarized the extensive results from previous studies for identifying the issues, the root causes, and the evaluation measures to be used for alternative fuel cycle and technology options. The importance of the fuel cycle strategy is discussed, as this directly affects the ability of an alternative fuel cycle to address the issues with nuclear power. The technology options are reviewed for the four major technology areas, fuel type (form and content), reactors and irradiation, processing, and disposal. The general capabilities of each option are summarized with respect to the potential effect that the option could have in addressing the nuclear power issues. The report concludes with a discussion of the decision framework for both nuclear fuel cycle strategies and the associated technology options, recognizing the overall advantages and limitations of various choices.A number of observations can be made at this stage of the AFCI Options Study. It is seen that the only fuel cycle strategy that can have a significant impact, i.e., an order of magnitude or more change, with respect to the nuclear power issues is continuous recycle of all transuranic (TRU) elements. There may be a special case for near-complete burnup of UNF that could also result in significant impact on the issues, making once-through and limited recycle strategies more attractive, since such an approach is essentially equivalent to a continuous recycle strategy where all TRU is recycled. However, after review of the technical issues, this possibility is considered impractical, maybe even impossible. Deciding the fuel cycle strategy is the important first step in considering alternative nuclear fuel cycle systems.Technology options exist for many areas of a nuclear fuel cycle. For fuel type, either uranium-based or thorium-based, it is only in the case of continuous recycle where these two fuel types exhibit different characteristics, and it is important to emphasize that this difference only exists for a fissile breeder strategy. The comparison between the thorium/U-233 and uranium/Pu-239 option shows that the thorium option would have lower, but probably not significantly lower, TRU inventory and disposal requirements, both having essentially equivalent proliferation risks. For these reasons, the choice between uraniumbased fuel and thorium-based fuels is seen basically as one of preference, with no fundamental difference in addressing the nuclear power issues. Since no infrastructure currently exists in the U.S. for thoriumbased fuels, and processing of thorium-based fuels is at a lower level of technical maturity when compared to processing of uranium-based fuels, costs and RD&D requirements for using thorium are anticipated to be higher. The availability and utilization of thorium-based fuels along with the uranium fuel technology in the U.S. would however make available more nuclear fuel resources for future nuclear expansion.

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