U.S. Department of Energy R&D Program on Developing the Technical Basis for SPent Fuel Extended Storage and Subsequent Transportation.
Abstract not provided.
Sorenson, Ken B.↗
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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Development of the SharkFin Distribution for Fuel Lifetime Estimates in Severe Accident Codes.
Abstract not provided.
Denman, Matthew R↗
Development of the SharkFin Distribution for Fuel Lifetime Estimates in Severe Accident Codes.
Abstract not provided.
Denman, Matthew R↗
Laser Shock Fresh Fuel Bond Strength Studies
Laser-based characterization of base monolithic U-10Mo fuel is being conducted by the USHPRR Fuel Qualification project to support fabrication development and ensure the fuel maintains mechanical integrity and does not delaminate during normal operating conditions. Characterization involves laser shock experiments, combined with laser-based ultrasonic scanning, to evaluate the bonding integrity and relative strength of interfaces within fuel plates. This report documents fresh fuel studies that were carried out on a series of fuel plates manufactured at Los Alamos National Laboratory in which various, controlled levels of interfacial contamination were intentionally introduced into the fuel plates during fabrication in order to vary the bond strength. Additional scoping studies were conducted on several developmental fuel plates supplied by the USHPRR Fuel Fabrication Pillar in which the Zr diffusion barrier was applied to the U-Mo foils by electroplating and plasma spraying. The electroplating and plasma spraying processes are being evaluated as potential alternatives to the baseline co-rolling fabrication process.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
A computational and experimental study of a High Velocity Oxy-Fuel System for MHD Generation system development
Presented by NETL at ASME Heat Transfer, Fluids Engineering, & Nanochannels, Microchannels, and Minichannels Conferences, 07/16
Huckaby, Ernest David↗
Development of an internally cooled annular fuel bundle for pressurized heavy water reactors
A number of preliminary studies have been conducted at Atomic Energy of Canada Limited to explore the potential of using internally cooled annular fuel (ICAF) in CANDU reactors including finite element thermo-mechanical modelling, reactor physics, thermal hydraulics, fabrication and mechanical design. The most compelling argument for this design compared to the conventional solid-rod design is the significant reduction in maximum fuel temperature for equivalent LERs (linear element ratings). This feature presents the potential for power up-rating or higher burnup and a decreased defect probability due to in-core power increases. The thermal-mechanical evaluation confirmed the significant reduction in maximum fuel temperatures for ICAF fuel compared to solid-rod fuel for equivalent LER. The maximum fuel temperature increase as a function of LER increase is also significantly less for ICAF fuel. As a result, the sheath stress induced by an equivalent power increase is approximately six times less for ICAF fuel than solid-rod fuel. This suggests that the power-increase thresholds to failure (due to stress-corrosion cracking) for ICAF fuel should be well above those for solid-rod fuel, providing improvement in operation flexibility and safety.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Development of the SharkFin Distribution for Fuel Lifetime Estimates in Severe Accident Codes
Historically, MELCOR has employed models at various degrees of fidelity for evaluating fuel mechanical response to the effects of cladding oxidation, material interactions (i.e., intermetallic formation), Zircaloy melting, fuel swelling, and other processes that occur at very high temperatures. In lieu of detailed models, a simple temperature-based criterion is used to define the threshold beyond which normal ('intact') fuel rod geometry can no longer be maintained, and the core materials at a particular location collapse into particulate debris. The temperature-based criterion reflects physico-chemical processes that affect fuel rod integrity. Using a composite of information, such as from the PHEBUS studies, four data points were log-linearly interpolated to create the rod collapse criteria used in the SOARCA study. This time-at-temperature (TaT) criterion was introduced in an attempt to avoid non-physical cliff-edge effects that are observed during a calculation when fuel temperatures are predicted to hover just below a failure temperature for extended periods. However, the code still models local rod collapse due to high temperature as a discrete and near-instantaneous (over one time step) event at each core cell. This paper introduces the SharkFin statistical model for TaT fuel failure relationships whose median curve has recently been adopted as the default fuel failure criteria in MELCOR. (authors)
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Extension of the DIF3D Code for Molten Salt Reactor Analysis
The molten salt reactor (MSR) with the fuel dissolved into the liquid salt has been selected as one of the six Generation-IV reactors due to its excellent characteristics in the aspects of sustainability, economy, passive safety, and resource utilization. In a MSR, the fuel salt is circulated throughout the whole system and thus some of delayed neutron precursors generated in the core decay in position of low importance or even out of the core. As a result, the multiplication factor (k-eff) of MSR is smaller than that of a reactor of stationary fuel when all the other conditions are same. Therefore, the neutronics code developed for stationary fuel cannot be applied directly to MSR analysis. In this paper, we describe the extension and application of the DIF3D code to MSR neutronics analysis. The DIF3D code system is a multi-group steady-state neutron diffusion and transport theory solver. It provides three flux solution options: finite-difference diffusion theory, nodal diffusion theory, and variational nodal transport theory methods. Eigenvalue, adjoint, fixed source and criticality (concentration) search problems are permitted. The DIF3D code has recently been modified to model the flowing fuel. To verify the new capability of DIF3D, the MSFR [4] core was analyzed with a wide range of velocity field of fuel salt and time spent outside of the core.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
SiC-CMC-Zircaloy-4 Nuclear Fuel Cladding Performance during 4-Point Tubular Bend Testing
The U.S. Department of Energy Office of Nuclear Energy (DOE NE) established the Light Water Reactor Sustainability (LWRS) program to develop technologies and other solutions to improve the reliability, sustain the safety, and extend the life of current reactors. The Advanced LWR Nuclear Fuel Development Pathway in the LWRS program encompasses strategic research focused on improving reactor core economics and safety margins through the development of an advanced fuel cladding system. Recent investigations of potential options for “accident tolerant” nuclear fuel systems point to the potential benefits of silicon carbide (SiC) cladding. One of the proposed SiC-based fuel cladding designs being investigated incorporates a SiC ceramic matrix composite (CMC) as a structural material supplementing an internal Zircaloy-4 (Zr-4) liner tube, referred to as the hybrid clad design. Characterization of the advanced cladding designs will include a number of out-of-pile (nonnuclear) tests, followed by in-pile irradiation testing of the most promising designs. One of the out-of-pile characterization tests provides measurement of the mechanical properties of the cladding tube using four point bend testing. Although the material properties of the different subsystems (materials) will be determined separately, in this paper we present results of 4-point bending tests performed on fully assembled hybrid cladding tube mock-ups, an assembled Zr-4 cladding tube mock-up as a standard and initial testing results on bare SiC-CMC sleeves to assist in defining design parameters. The hybrid mock-up samples incorporated SiC-CMC sleeves fabricated with 7 polymer impregnation and pyrolysis (PIP) cycles. To provide comparative information; both 1- and 2-ply braided SiC-CMC sleeves were used in this development study. Preliminary stress simulations were performed using the BISON nuclear fuel performance code to show the stress distribution differences for varying lengths between loading points and clad configurations. The 2-ply sleeve samples show a higher bend momentum compared to those of the 1-ply sleeve samples. This is applicable to both the hybrid mock-up and bare SiC-CMC sleeve samples. Comparatively both the 1- and 2-ply hybrid mock-up samples showed a higher bend stiffness and strength compared with the standard Zr-4 mock-up sample. The characterization of the hybrid mock-up samples showed signs of distress and preliminary signs of fraying at the protective Zr-4 sleeve areas for the 1-ply SiC-CMC sleeve. In addition, the microstructure of the SiC matrix near the cracks at the region of highest compressive bending strain shows significant cracking and flaking. The 2-ply SiC-CMC sleeve samples showed a more bonded, cohesive SiC matrix structure. This cracking and fraying causes concern for increased fretting during the actual use of the design. Tomography was proven as a successful tool to identify open porosity during pre-test characterization. Although there is currently insufficient data to make conclusive statements regarding the overall merit of the hybrid cladding design, preliminary characterization of this novel design has been demonstrated.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Fuel Flexible Combustion Systems for High-Efficiency Utilization of Opportunity Fuels in Gas Turbines
The purpose of this program was to develop low-emissions, efficient fuel-flexible combustion technology which enables operation of a given gas turbine on a wider range of opportunity fuels that lie outside of current natural gas-centered fuel specifications. The program encompasses a selection of important, representative fuels of opportunity for gas turbines with widely varying fundamental properties of combustion. The research program covers conceptual and detailed combustor design, fabrication, and testing of retrofitable and/or novel fuel-flexible gas turbine combustor hardware, specifically advanced fuel nozzle technology, at full-scale gas turbine combustor conditions. This project was performed over the period of October 2008 through September 2011 under Cooperative Agreement DE-FC26-08NT05868 for the U.S. Department of Energy/National Energy Technology Laboratory (USDOE/NETL) entitled "Fuel Flexible Combustion Systems for High-Efficiency Utilization of Opportunity Fuels in Gas Turbines". The overall objective of this program was met with great success. GE was able to successfully demonstrate the operability of two fuel-flexible combustion nozzles over a wide range of opportunity fuels at heavy-duty gas turbine conditions while meeting emissions goals. The GE MS6000B ("6B") gas turbine engine was chosen as the target platform for new fuel-flexible premixer development. Comprehensive conceptual design and analysis of new fuel-flexible premixing nozzles were undertaken. Gas turbine cycle models and detailed flow network models of the combustor provide the premixer conditions (temperature, pressure, pressure drops, velocities, and air flow splits) and illustrate the impact of widely varying fuel flow rates on the combustor. Detailed chemical kinetic mechanisms were employed to compare some fundamental combustion characteristics of the target fuels, including flame speeds and lean blow-out behavior. Perfectly premixed combustion experiments were conducted to provide experimental combustion data of our target fuels at gas turbine conditions. Based on an initial assessment of premixer design requirements and challenges, the most promising sub-scale premixer concepts were evaluated both experimentally and computationally. After comprehensive screening tests, two best performing concepts were scaled up for further development. High pressure single nozzle tests were performed with the scaled premixer concepts at target gas turbine conditions with opportunity fuels. Single-digit NOx emissions were demonstrated for syngas fuels. Plasma-assisted pilot technology was demonstrated to enhance ignition capability and provide additional flame stability margin to a standard premixing fuel nozzle. However, the impact of plasma on NOx emissions was observed to be unacceptable given the goals of this program and difficult to avoid.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
Predicting Sooting Tendencies from Chemical Structure with Experimental and Theoretical Insight
Particulate matter (PM) emissions from internal combustion engines negatively impact public health and global climate. These problems are exacerbated by newer gasoline direct injection engines, which are more fuel-efficient, but also produce more soot than traditional spark ignited engines. Reducing soot formation is therefore of paramount importance in the development of new fuels. A fuel's sooting tendency is a quantitative parameter that describes the sooting behavior of a pure compound or fuel mixture. The yield sooting index (YSI), developed by McEnally and Pfefferle, accurately measures sooting tendencies using small sample quantities. Using an experimental sooting tendency database, we have developed a predictive model for sooting behavior from a quantitative structure-activity relationship (QSAR). It was developed so that input molecules are first decomposed into individual carbon-type fragments for which the sooting tendency contribution can be assigned based on a Bayesian linear regression against the experimental database. The model's predictive accuracy is comparable to its training performance using leave-one-out cross-validation. We have used this model to provide quantitative insights into the effects of chemical structure on soot formation, but excitingly, we have also been able to readily identify the presence of more complicated kinetic sooting mechanisms for structures which are extreme outliers. Oxygenated aromatics can be produced readily from biomass as renewable sources and oxygenated aromatics with very similar structures tend to have a much lower sooting tendency, for example methoxybenzene (anisole, 107), 2-methylphenol (m-cresol, 103), 2-ethylphenol (120), 3-ethylphenol (138) and 1-phenylethanol (142). Thus, the presence of just one oxygen atom in an aromatic compound can drastically alter the reaction pathways leading to soot precursors. We have applied density functional theory (DFT) calculations and flow reactor experiments to examine how oxygenation alters reaction pathways in a combustion environment. This study has allowed us to gain understanding on how the location of an oxygenated functional group influences soot formation. Our work provides a blueprint for the design of oxygenated fuels from biomass, which minimize the production of soot in low oxygen environments.
09 BIOMASS FUELS↗
Bond Strength of Plasma Sprayed Zr Diffusion Barrier on U-Mo Fuels
The United States government is continually committed to strengthening nuclear security and nonproliferation for reducing the threat of radioactive materials acquisition by terrorists. To meet this important mission, the US Department of Energy and National Nuclear Security Agency's (NNSA) Office of Material Management and Minimization (M{sup 3}) Reactor Conversion Program (CONVERT) seeks to minimize the use of highly enriched uranium (HEU) in civilian applications through work with governments and facilities around the world to convert research reactors to the use of non-weapons-usable low enriched uranium (LEU) fuels. Each reactor converted not only eliminates the need for HEU at civilian sites, but also reduces the amount of HEU being manufactured, stored, and transported, where the nuclear material is most vulnerable. In instances where suitable LEU fuels do not exist for the conversion of particular reactors, CONVERT contributes to development of new LEU fuels. Currently, the CONVERT Program is committed to development of a high-density U-Mo fuel that will be able to convert high performance research reactors, while establishing an efficient and economic fabrication capability to manufacture the fuel. To that end, Los Alamos National Laboratory (LANL) has been tasked with development of a method to affix zirconium (Zr) metal fuel diffusion barrier via plasma spraying, which will prevent a reaction between the U-Mo fuel and the 6061 aluminum cladding. A successful diffusion barrier requires adequate Zr layer thickness, uniform coverage, sufficient bonding at the Zr/fuel and Zr/aluminum cladding interface, and maintenance of the original nuclear fuel properties i.e. physical dimensions, alloy composition and dispersion, crystallographic phase concentration, neutronics, etc. This work outlines development of the Zr plasma spray processing techniques, parameters affecting the diffusion barrier/nuclear fuel bond strength, and characterization of the Zr diffusion barrier. (authors)
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Results from Fuel Matrix Degradation Model Parameterization Experiments and Model Development Activities
This work is being performed as part of the DOE NE Spent Fuel and Waste Science and Technology Campaign, Argillite and Crystalline Rock R&D work packages: SF-20AN01030101 and SF-20AN01030201 respectively. This document is submitted in fulfillment of milestone M4SF-20AN010301013 for Argillite R&D and the milestone M4SF-20AN010302013 for Crystalline R&D
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Advanced Fuels Campaign FY 2014 Accomplishments Report
The mission of the Advanced Fuels Campaign (AFC) is to perform Research, Development, and Demonstration (RD&D) activities for advanced fuel forms (including cladding) to enhance the performance and safety of the nation’s current and future reactors; enhance proliferation resistance of nuclear fuel; effectively utilize nuclear energy resources; and address the longer-term waste management challenges. This includes development of a state-of-the art Research and Development (R&D) infrastructure to support the use of a “goal-oriented science-based approach.” In support of the Fuel Cycle Research and Development (FCRD) program, AFC is responsible for developing advanced fuels technologies to support the various fuel cycle options defined in the Department of Energy (DOE) Nuclear Energy Research and Development Roadmap, Report to Congress, April 2010. AFC uses a “goal-oriented, science-based approach” aimed at a fundamental understanding of fuel and cladding fabrication methods and performance under irradiation, enabling the pursuit of multiple fuel forms for future fuel cycle options. This approach includes fundamental experiments, theory, and advanced modeling and simulation. The modeling and simulation activities for fuel performance are carried out under the Nuclear Energy Advanced Modeling and Simulation (NEAMS) program, which is closely coordinated with AFC. In this report, the word “fuel” is used generically to include fuels, targets, and their associated cladding materials. R&D of light water reactor (LWR) fuels with enhanced accident tolerance is also conducted by AFC. These fuel systems are designed to achieve significantly higher fuel and plant performance to allow operation to significantly higher burnup, and to provide enhanced safety during design basis and beyond design basis accident conditions. The overarching goal is to develop advanced nuclear fuels and materials that are robust, have high performance capability, and are more tolerant to accident conditions than traditional fuel systems. AFC management and integration activities included continued support for international collaborations, primarily with France, Japan, the European Union, Republic of Korea, and China, as well as various working group and expert group activities in the Organization for Economic Cooperation and Development Nuclear Energy Agency (OECD-NEA) and the International Atomic Energy Agency (IAEA). Three industry-led Funding Opportunity Announcements (FOAs) and two university-led Integrated Research Projects (IRPs), funded in 2013, made significant progress in fuels and materials development. All are closely integrated with AFC and Accident Tolerant Fuels (ATF) research. Accomplishments made during fiscal year (FY) 2014 are highlighted in this report, which focuses on completed work and results. The process details leading up to the results are not included; however, the lead technical contact is provided for each section.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Wetted foam liquid fuel ICF target experiments
We are developing a new NIF experimental platform that employs wetted foam liquid fuel layer ICF capsules. We will use the liquid fuel layer capsules in a NIF sub-scale experimental campaign to explore the relationship between hot spot convergence ratio (CR) and the predictability of hot spot formation. DT liquid layer ICF capsules allow for flexibility in hot spot CR via the adjustment of the initial cryogenic capsule temperature and, hence, DT vapor density. Our hypothesis is that the predictive capability of hot spot formation is robust and 1D-like for a relatively low CR hot spot (CR~15), but will become less reliable as hot spot CR is increased to CR>20. Simulations indicate that backing off on hot spot CR is an excellent way to reduce capsule instability growth and to improve robustness to low-mode x-ray flux asymmetries. In the initial experiments, we will test our hypothesis by measuring hot spot size, neutron yield, ion temperature, and burn width to infer hot spot pressure and compare to predictions for implosions with hot spot CR's in the range of 12 to 25. Larger scale experiments are also being designed, and we will advance from sub-scale to full-scale NIF experiments to determine if 1D-like behavior at low CR is retained as the scale-size is increased. The long-term objective is to develop a liquid fuel layer ICF capsule platform with robust thermonuclear burn, modest CR, and significant α-heating with burn propagation.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Advanced surface plasma nitriding for development of corrosion resistant and accident tolerant fuel cladding: Final Report
Although various surface coating techniques have been proposed to increase oxidation and corrosion resistance of fuel cladding materials, the de-bonding of the coating layer with the original cladding matrix under exposure to coolants makes such approaches unsuitable for reactor applications. Furthermore, the feasibility of techniques for large scale processing on cladding tubes remains another technological bottleneck. This project aims to develop a hollow cathode plasma nitriding technique to solve the above issues. Starting with alloys of DOE interest, the team will apply an advanced surface plasma nitriding technique to convert alloy surface layers into nitride layers for better structural integrity and compatibility with both coolants and nuclear fuels. The technique can form uniform nitride layers on both inner and outer surfaces of cylindrical hollow tubes. Both treated and untreated samples will be irradiated by using Fe self ions or dual beams of Fe ions and He ions. Various microstructural characterizations and mechanical property measurements will be performed. For outside surfaces, samples will be tested in high temperature water and liquid molten salt to evaluate their corrosion resistance and compatibility with coolants for LWR and fast reactor applications. For inside surfaces, solid-to-solid diffusion couple experiments will be used to study interface reactions of nitrided samples with uranium, to test whether a nitrided layer can slow down fuel-cladding interactions. The project will impact both the development of advanced methods for manufacturing and the development of advanced reactor in-core structural materials. The proposed technique can form nitride layers on alloys of irregular shapes without an edging effect - an issue encountered in traditional plasma nitriding processes, and is suitable for surface processing of other in-core components.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Lattice cell and full core physics of internally cooled annular fuel in heavy water moderated reactors
A program is underway at Atomic Energy of Canada Limited (AECL) to develop a new fuel bundle concept to enable greater burnups for PT-HWR (pressure tube heavy water reactor) cores. One option that AECL is investigating is an internally cooled annular fuel (ICAF) element concept. ICAF contains annular cylindrical pellets with cladding on the inner and outer diameters. Coolant flows along the outside of the element and through the centre. With such a concept, the maximum fuel temperature as a function of linear element rating is significantly reduced compared to conventional, solid-rod type fuel. The preliminary ICAF bundle concept considered in this study contains 24 half-metre long internally cooled annular fuel elements and one non-fuelled centre pin. The introduction of the non-fuelled centre pin reduces the coolant void reactivity (CVR), which is the increase in reactivity that occurs on voiding the coolant in accident scenarios. Lattice cell and full core physics calculations of the preliminary ICAF fuel bundle concept have been performed for medium burnups of approximately 18 GWd/tU using WIMS-AECL and reactor fuel simulation program (RFSP). The results will be used to assist in concept configuration optimization. The effects of radial and axial core power distributions, linear element power ratings, refuelling rates and operational power ramps have been analyzed. The results suggest that burnups of greater than 18 GWd/tU can be achieved in current reactor designs. At approximately 18 GWd/tU, expected maximum linear element ratings in a PT-HWR with online-refuelling are approximately 90 kW/m. These conditions would be prohibitive for solid-rod fuel, but may be possible in ICAF fuel given the reduced maximum fuel temperature as a function of linear element rating. (authors)
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗