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At least 1,027 records · Page 57

Conceptual Phase Neutronic and Thermal Analyses for the LEU Conversion of the Transient Reactor Test Facility (TREAT)

The Transient Reactor Test Facility (TREAT) is an experimental reactor designed for transient testing of nuclear reactor fuels and other materials. TREAT is located at the Idaho National Laboratory (INL). It was operated from 1959 until 1994, when it was placed on nonoperational standby. Preparations for the restart of TREAT are now underway. Simultaneously, work is being performed to support the conversion of TREAT from its current high enriched uranium (HEU) fuel to low enriched uranium (LEU, defined as uranium with less than 20% {sup 235}U) fuel, under the support of the Department of Energy (DOE) National Nuclear Security Administration (NNSA) Material Management and Minimization (M{sup 3}) reactor conversion program. Following the pre-conceptual phase of the TREAT conversion project (which included assessments of conversion feasibility, including LEU fuel element fabrication feasibility), conceptual phase work was performed to evaluate potential LEU fuel element designs for TREAT. Simultaneously, activities including scale-up development work for fuel fabrication and mock-up element production were performed by the INL Fuel Engineering and Design (FED) team. Utilizing the lessons learned in the analysis and fabrication work, an LEU conceptual design description was collaboratively established and evaluated in detail. A summary of this work and corresponding example results are presented here. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Comparative post-irradiation examination of high burnup U-19Pu-10Zr: Assessing steady-state irradiation behavior against historical and modeled fuel performance

Here, the development of next-generation sodium-cooled fast reactors necessitates comprehensive research on metallic fuels to maximize economic performance while ensuring safe operation. In this study, we investigated the steady-state irradiation behavior of two high burnup U-19Pu-10Zr fuel pins, DP-36 and DP-40, in preparation for planned safety testing. Post-irradiation examination (PIE) was performed to quantify fuel column elongation, regions of low-density at the top of the fuel column, pin deformation, fission product distribution, fractional fission gas release, microstructural evolution, and fuel constituent redistribution. Benchmarking against existing PIE data from U-19Pu-10Zr fuel pins irradiated in EBR-II revealed consistent patterns in fuel column elongation and cladding diametral strain. However, both pins exhibited longer low-density structures, and destructive examination of DP-36 revealed more complex constituent redistribution patterns compared to previously reported data for ternary fuel pins. The steady-state irradiation of both pins was also modeled using BISON. Comparisons of PIE results with modeled predictions showed overall agreement in fractional fission gas release but consistent overestimation of axial and radial swelling due to gaseous and solid swelling models. These findings underscore the critical importance of pre-test characterization on test and sibling pins to accurately capture steady-state fuel behavior ahead of transient testing, thus establishing a baseline for post-test comparison. Additionally, these analyses identified key data gaps that warrant further investigation to improve the understanding and prediction of fuel swelling, thereby enhancing the synergy between modeling and experimental efforts in supporting accident testing.

BISON↗

Developing A Laser Shockwave Model For Characterizing Diffusion Bonded Interfaces

12. Other advances in QNDE and related topics: Preferred Session Laser-ultrasonics Developing A Laser Shockwave Model For Characterizing Diffusion Bonded Interfaces 41st Annual Review of Progress in Quantitative Nondestructive Evaluation Conference QNDE Conference July 20-25, 2014 Boise Centre 850 West Front Street Boise, Idaho 83702 James A. Smith, Jeffrey M. Lacy, Barry H. Rabin, Idaho National Laboratory, Idaho Falls, ID ABSTRACT: The US National Nuclear Security Agency has a Global Threat Reduction Initiative (GTRI) which is assigned with reducing the worldwide use of high-enriched uranium (HEU). A salient component of that initiative is the conversion of research reactors from HEU to low enriched uranium (LEU) fuels. An innovative fuel is being developed to replace HEU. The new LEU fuel is based on a monolithic fuel made from a U-Mo alloy foil encapsulated in Al-6061 cladding. In order to complete the fuel qualification process, the laser shock technique is being developed to characterize the clad-clad and fuel-clad interface strengths in fresh and irradiated fuel plates. The Laser Shockwave Technique (LST) is being investigated to characterize interface strength in fuel plates. LST is a non-contact method that uses lasers for the generation and detection of large amplitude acoustic waves to characterize interfaces in nuclear fuel plates. However the deposition of laser energy into the containment layer on specimen’s surface is intractably complex. The shock wave energy is inferred from the velocity on the backside and the depth of the impression left on the surface from the high pressure plasma pulse created by the shock laser. To help quantify the stresses and strengths at the interface, a finite element model is being developed and validated by comparing numerical and experimental results for back face velocities and front face depressions with experimental results. This paper will report on initial efforts to develop a finite element model for laser shock.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Development of Zirconium-Silicide Coatings for Improved Performance Zirconium-Alloy Fuel Cladding

There is considerable interest in the development of coatings for zirconium-alloy fuel cladding used in light water reactors (LWR) to improve their oxidation resistance during high temperature accident conditions and to enhance performance under normal operating conditions. These coatings should also enhance the heat transfer characteristics of the cladding surface so that heat from the fuel rod is efficiently transferred into the water coolant. One potential candidate coating material is zirconium-silicide. Transition metal silicides have been generally shown to have outstanding oxidation resistance. Zirconium-silicide is particularly attractive because Zr is strongly oxophilic, so that the Zr-silicide layer is expected to bond more strongly to the inner, native ZrO{sub 2} layer. The relative proximity of the free energy of formation of oxides of Zr and Si can lead to alternating multilayered oxide structures with radiation damage resistance. Additionally, oxidation of zirconium silicide can produce excellent corrosion resistant glassy zircon (ZrSiO{sub 4}) and silica (SiO{sub 2}), possessing self-healing qualities. This paper reports results of our results of high temperature oxidation tests of bulk zirconium-silicide and coatings of zirconium-silicide deposited on zirconium-alloy test flats and cladding tube configurations using plasma vapor deposition (PVD) process. We also report our initial results on the experimental facility for studying boiling characteristics of coated cladding tubes in prototypic pressurized water conditions. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

BISON Development and Validation for Priority LWR-ATF concepts

Over the years, the Nuclear Energy Advanced Modeling and Simulation (NEAMS) (2015-2018, 2020) and Consortium for Advanced Simulation of Light Water Reactors (CASL) (2019) programs have provided support for development of Accident Tolerant Fuel (ATF) material models in the BISON fuel performance code. Since the beginning, the goal has been to utilize a multiscale modeling approach to gain a physical understanding of the fuel concepts of interest and to develop mechanistic models in the absence of a large amount of experimental data. This work builds upon that of previous years. In particular we present newly updated fission gas release models for both gas behavior in Cr 2 O 3 -doped UO 2 and U 3 Si 2 fuels, and a new creep model for U 3 Si 2 . The validation exercises completed last year are revisited with the latest models and the results updated. A brief summary of recent modeling activities for FeCrAl cladding is also provided.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Use of a Lignin-Based Admixture for Tailoring the Rheological Properties of Mortars for 3D Printing: Preprint

Efforts toward decarbonizing construction materials and industrial processes related to cement and concrete can be aided via multifaceted approaches that target alternative admixtures as well as precision control of fabrication. Chemical admixtures for water reduction have played a crucial role in the development of advanced concrete mixtures. Newer biomass processing techniques developed for aviation fuel production from corn stover biomass produce a more reactive lignin byproduct that is suitable for chemical modifications to mimic the properties of polycarboxylate ether admixtures with a smaller carbon footprint. The present study examines the use of lignin-based water-reducing admixture in cement pastes and mortar mixtures for 3D printing. The experimental program explores the use of different dosages of lignin-based admixture to produce 3D-printed samples with appropriate extrudability and buildability. The rheological characterization was performed to determine the flow curve of various mixtures. Finally, the heat of hydration of cement pastes was monitored via isothermal calorimetry to assess the impact of lignin-based admixtures on the hydration process of cement. The results of this study indicate that the use of biomass by-products, such as lignin-based admixtures have great potential to effectively control the fresh-state properties of cement-based materials.

bio-based admixtures↗

Development and Demonstration of a New Generation High Efficiency 10kW Stationary Fuel Cell System

The overall project objective is to develop and demonstrate a polymer electrolyte membrane fuel cell combined heat and power (PEMFC CHP) system that provides the foundation for commercial, mass produced units which achieve over 40% electrical efficiency (fuel to electric conversion) from 50-100% load, greater than 70% overall efficiency (fuel to electric energy + usable waste heat energy conversion), have the potential to achieve 40,000 hours durability on all major process components, and can be produced in high volumes at under $\$$400/kW (revised to $\$$750/kW per 2011 DOE estimates) capital cost.

08 HYDROGEN↗

Compatibility Assessment of Fuel System Elastomers with Bio-oil and Diesel Fuel

Bio-oil derived via fast pyrolysis is being developed as a renewable fuel option for petroleum distillates. The compatibility of neat bio-oil with six elastomer types was evaluated against the elastomer performance in neat diesel fuel, which served as the baseline. The elastomers included two fluorocarbons, six acrylonitrile butadiene rubbers (NBRs), and one type each of fluorosilicone, silicone, styrene butadiene rubber (SBR), polyurethane, and neoprene. Specimens of each material were exposed to the liquid and gaseous phases of the test fuels for 4 weeks at 60 degrees C, and properties in the wetted and dried states were measured. Exposure to bio-oil produced significant volume expansion in the fluorocarbons, NBRs, and fluorosilicone; however, excessive swelling (over 80%) was only observed for the two fluorocarbons and two NBR grades. The polyurethane specimens were completely degraded by the bio-oil. In contrast, both silicone and SBR exhibited lower swelling levels in bio-oil compared to neat diesel fuel. The implication is that, while polyurethane and fluorocarbon may not be acceptable seal materials for bio-oils, silicone may offer a lower cost alternative.

09 BIOMASS FUELS↗

Development and assessment of solar-thermal-activated fuel production: Phase 1, summary

Sandia National Laboratories has for many years been engaged in investigating and developing the science and technology of solar thermochemistry for solar fuel applications under the banner “Sunshine to Petrol.” This report summarizes BP‐funded solar thermochemical work performed from November 2011 through May 2012. This “phase one” effort centered on performance mapping of the Counter‐Rotating‐Ring Receiver Reactor Recuperator (CR5) prototype, a thermochemical heat engine for splitting CO 2 (and/or H 2 O) to produce CO (H 2 ) and O 2 . The bulk of the on‐sun testing effort was performed with 8 ceria‐finned rotating rings. During operation, argon is injected into the reduction side of the CR5 while CO 2 is provided to the oxidation side.

Miller, James Edward↗

Real-Time Detection Methods to Monitor TRU Compositions in UREX+Process Streams

The U.S. Department of Energy has developed advanced methods for reprocessing spent nuclear fuel. The majority of this development was accomplished under the Advanced Fuel Cycle Initiative (AFCI), building on the strong legacy of process development R&D over the past 50 years. The most prominent processing method under development is named UREX+. The name refers to a family of processing methods that begin with the Uranium Extraction (UREX) process and incorporate a variety of other methods to separate uranium, selected fission products, and the transuranic (TRU) isotopes from dissolved spent nuclear fuel. It is important to consider issues such as safeguards strategies and materials control and accountability methods. Monitoring of higher actinides during aqueous separations is a critical research area. By providing on-line materials accountability for the processes, covert diversion of the materials streams becomes much more difficult. The importance of the nuclear fuel cycle continues to rise on national and international agendas. The U.S. Department of Energy is evaluating and developing advanced methods for safeguarding nuclear materials along with instrumentation in various stages of the fuel cycle, especially in material balance areas (MBAs) and during reprocessing of used nuclear fuel. One of the challenges related to the implementation of any type of MBA and/or reprocessing technology (e.g., PUREX or UREX) is the real-time quantification and control of the transuranic (TRU) isotopes as they move through the process. Monitoring of higher actinides from their neutron emission (including multiplicity) and alpha signatures during transit in MBAs and in aqueous separations is a critical research area. By providing on-line real-time materials accountability, diversion of the materials becomes much more difficult. The objective of this consortium was to develop real time detection methods to monitor the efficacy of the UREX+ process and to safeguard the separated TRUs against unlawful diversion from within a processing facility. To achieve this, a comprehensive strategy was implemented to incorporate traditional detectors and advanced Tensioned Metastable Fluid (TMFD) metastable fluid detectors (developed, in part, under this project) into a novel detector assembly coupled to the UREX+ centrifugal contactor array. The sections below provide a brief summary of the technical achievements completed during this project. The principal outcomes are documented in more complete details contained the doctoral dissertations and masters theses, journal papers, conference proceedings and additional items for more than the 35 publications that are listed in the program bibliography in Section 3.

McDeavitt, Sean M.↗

High-Activity Dealloyed Catalysts

Reduction of costly Pt usage in proton exchange membrane fuel cell electrodes is one of the major challenges towards development and commercialization of fuel cell vehicles. Although few have met the initial-kinetic activity requirements in a realistic fuel cell device, no catalyst material has ever met the demanding fuel cell durability targets set by DOE. In this project, a team of 4 universities and 2 companies came together to investigate a concept that appeared promising in preliminary non-fuel cell tests then to further develop the catalyst to a mature level ready for vehicle implementation. The team consists of academia with technical leadership in their respective areas, a catalyst supplier, and a fuel cell system integrator.The tightly collaborative project enabled development of a highly active and durable catalyst with performance that significantly exceeds that of previous catalysts and meets the DOE targets for the first time (Figure 1A). The catalyst was then further evaluated in full-active-area stack in a realistic vehicle operating condition (Figure 1B). This is the first public demonstration that one can realize the performance benefit and Pt cost reduction over a conventional pure Pt catalyst in a long-term realistic PEMFC system. Furthermore, systematic analyses of a range of catalysts with different performance after fuel cell testing allowed for correlation between catalyst microstructure and its electrocatalytic activity and durability. This will in turn aid future catalyst development.

30 DIRECT ENERGY CONVERSION↗

DRAFT: Accident Tolerant Fuels Draft Implementation Plan

The ATF Implementation Plan integrates DOE’s objectives and goals with the national laboratory’s expertise and infrastructure in support of the technology development by three industry partners. DOE’s plan is to develop advanced LWR fuels with enhanced accident tolerance in response to the Congressional request and to install a lead fuel assembly containing accident tolerant fuel technology in a U.S. commercial nuclear power plant by 2022. DOE has three contracts in place with each of the principle US commercial nuclear fuel vendors in support of ATF research and development, AREVA Services LLC, General Electric, and Westinghouse LLC. The purpose of the ATF Implementation Plan is to describe the technology development and progress required to insert one (or possible two) concepts as a LFR or LFA in a commercial LWR by 2022. In particular, this document shows the integration between the functional documents guiding ATF development and provides a rough order of magnitude estimate of the required budget from FY2016 through FY2022. It is expected that after FY2022, the needed budget request would significantly decrease as works transitions from Phase 2 to Phase 3, corresponding to a decrease in DOE project responsibility and an increase in industry responsibility and associated funding support.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Developing a laser shockwave model for characterizing diffusion bonded interfaces

The US National Nuclear Security Agency has a Global Threat Reduction Initiative (GTRI) with the goal of reducing the worldwide use of high-enriched uranium (HEU). A salient component of that initiative is the conversion of research reactors from HEU to low enriched uranium (LEU) fuels. An innovative fuel is being developed to replace HEU in high-power research reactors. The new LEU fuel is a monolithic fuel made from a U-Mo alloy foil encapsulated in Al-6061 cladding. In order to support the fuel qualification process, the Laser Shockwave Technique (LST) is being developed to characterize the clad-clad and fuel-clad interface strengths in fresh and irradiated fuel plates. LST is a non-contact method that uses lasers for the generation and detection of large amplitude acoustic waves to characterize interfaces in nuclear fuel plates. However, because the deposition of laser energy into the containment layer on a specimen's surface is intractably complex, the shock wave energy is inferred from the surface velocity measured on the backside of the fuel plate and the depth of the impression left on the surface by the high pressure plasma pulse created by the shock laser. To help quantify the stresses generated at the interfaces, a finite element method (FEM) model is being utilized. This paper will report on initial efforts to develop and validate the model by comparing numerical and experimental results for back surface velocities and front surface depressions in a single aluminum plate representative of the fuel cladding.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

An improved methodology for numerical forensics analysis of spent reactor fuel

An improved system was developed to recover the initial parameters and operating conditions from spent nuclear fuel. This work is an expansion of a previous proof-of-concept system developed by the author. The improved system increases the fidelity of the forward model within the spent fuel forensic inverse analysis using two unique methodologies. The first improvement consists of developing a system to accurately create one-group neutron crosssection libraries for any user-specified reactor system. As such, a detailed model using the depletion code MONTEBURNS is developed. During MONTEBURNS execution, cross-section libraries are generated at every user specified burnup step in time. These libraries could be developed for many reactor systems, then housed in a database and used for analyzing spent fuel.

inverse depletion↗

Development of Radio Frequency Diesel Particulate Filter Sensor and Controls for Advanced Low Pressure Drop Systems to Reduce Engine Fuel Consumption (06B)

This project developed a radio frequencybased sensor for accurate measurement of diesel particulate filter (DPF) loading with advanced low pressuredrop aftertreatment systems. The resulting technology demonstrated engine efficiency improvements through optimization of the combined engineaftertreatment system while reducing emissions, system cost, and complexity to meet the DOE program objectives.

02 PETROLEUM↗

Accident-Tolerant Fuel

Advanced light water reactor (LWR) fuels have been developed incrementally for more than 60 years before the term Accident Tolerant Fuel (ATF) was created. There are many different categories of ATF concepts, which range from near-term marginal enhancements to fission gas release in fuel or hydrogen pickup in the cladding, to transformational fuel types with new engineered fission product barriers. In this work we characterize these different types of ATF, and give several important examples for each.We conclude that transformational ATF concepts have the greatest potential to enhance the traditional definition of defense-in-depth by enhancing current barriers and/or by providing additional barriers to fission product release. This objective can primarily be achieved by introducing a new fission product barrier that enhances defense-in-depth by design, for example the added barriers to fission product release in some engineered ATF concepts. We recommend future gap analyses and a phenomena identification and ranking to assess the applicability of existing safe acceptable fuel design limits and the standard review plan to specific ATF concepts.

Brown, Nicholas↗