AFCI Options Study

Abstract

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.

Scaling and energy transfer in rotating turbulence

“…The nonlinear spectral transfer of energy by the direct turbulent cascade and the associated energy spectrum are particularly interesting due to their direct connection to the dynamical processes governing rotating turbulence. Most of the available experimental data [1,2,3,4,5] yields no conclusive information on the expected self-similar scaling of the energy spectrum in the inertial range of scales and its dependence on the rotation frequency Ω. Although recent experiments [6,7,8] have shed some light on these issues, the scaling of two-point statistics in rotating turbulence remains a controversial topic.Direct numerical simulations [9,10,11,12,13,14,15,16] and large-eddy simulations, see e.g.…”

On a Long Term Strategy for the Success of Nuclear Power

“…One of the key points leading to the decision to investigate molten salt reactor technology is given in the Nuclear Fuel Cycle Evaluation and Screening of the United States [22]. Especially, in the Mass Flow Data Comparison details of the study indicating that Molten Salt Reactors (MSRs) have the potential for the highest (fissile material) utilization which result in the lowest material losses [23].…”

Comparison and Screening of Nuclear Fuel Cycle Options in View of Sustainable Performance and Waste Management

“…Such an approach is suitable to examine the impact of different perspectives on options' ranking order and it is widely applied in many studies. For instance a similar approach was followed within the US DOE supported study on evaluation and screening of NFCs [39]. …”