Sensitivity analysis and fuel performance of a control rod withdrawal in the generic fluoride-salt-cooled high temperature reactor
Not Available
Barthle, Jonathan L.↗
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Integration of full divertor detachment with improved core confinement for tokamak fusion plasmas
Divertor detachment offers a promising solution to the challenge of plasma-wall interactions for steady-state operation of fusion reactors. Here, we demonstrate the excellent compatibility of actively controlled full divertor detachment with a high-performance (β N ~ 3, H 98 ~ 1.5) core plasma, using high-β p (poloidal beta, β p > 2) scenario characterized by a sustained core internal transport barrier (ITB) and a modest edge transport barrier (ETB) in DIII-D tokamak. The high-β p high-confinement scenario facilitates divertor detachment which, in turn, promotes the development of an even stronger ITB at large radius with a weaker ETB. This self-organized synergy between ITB and ETB, leads to a net gain in energy confinement, in contrast to the net confinement loss caused by divertor detachment in standard H-modes. These results show the potential of integrating excellent core plasma performance with an efficient divertor solution, an essential step towards steady-state operation of reactor-grade plasmas.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Fuel Performance Design Basis for the Versatile Test Reactor
Not Available
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Physics reach of a low threshold scintillating argon bubble chamber in coherent elastic neutrino-nucleus scattering reactor experiments
Not Available
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Improved mixed oxide fuel calculations with the evaluated nuclear data library JEFF-3.2
In this study, an overestimation of the keff values for mixed oxide (MOX) fuels was identified with Monte Carlo (TRIPOLI-4) and deterministic (APOLLO2) calculations based on the Joint Evaluated Fission and Fusion (JEFF) evaluated nuclear data library. The overestimation becomes sizeable with Pit aging, reaching a reactivity change of Delta(p)similar or equal to+700 pcm for integral measurements carried out with MOX fuel containing a large amount of americium. This bias was observed for various critical configurations performed in the zero power reactor EOLE of the Commissariat a l'energie atomique et aux energies alternatives (CEA), Cadarache, France. The present work focuses on the improvements achieved with the new 239 PU and 241 Am evaluated nuclear data files available in the latest version of the JEFF library (JEFF-3.2). The resolved resonance range of the plutonium evaluation was reevaluated at Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee, with the Ski/NH code in collaboration with CEA Cadarache. The resonance parameters of the americium evaluation were obtained with the REFIT code in collaboration with the research institutes Institute for Reference Materials and Measurements aRmm, Geel, Belgium, and Institut de recherche sur les lois fondamentales de l'Univers ofio, Saclay, France.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Licensing Modernization Project for Advanced Reactor Technologies: FY 2018 Project Status Report
The promise of new nuclear technology and the future of commercial power in the United States (U.S.) are linked to the existence of an efficient and safety-focused regulatory review and licensing process. With an appropriate regulatory framework, reactor suppliers and regulators can design, license, build, and export advanced reactor units more effectively and efficiently and thereby help meet the growing need for clean and reliable energy. To help address the challenge of maintaining compatibility between the regulatory environment and new commercial nuclear plant designs, the U.S. Department of Energy (DOE) is supporting an industry-led effort called the Licensing Modernization Project (LMP). This cost-shared initiative, started in 2016 and scheduled to continue through mid-2019, targets amendment to key elements of the U.S. nuclear power reactor regulatory framework to specifically address licensing barriers in advanced-reactor concepts. The project is focused on updating guidance for certain technical licensing requirements that are largely incompatible with non-light-water reactors (non-LWR) and establish a new pathway for design-safety evaluations and license-application development. Upon completion, the project will have created a new pathway, founded on modern probabilistic assessment techniques, that offers developers, suppliers, regulators, and owner/operatorowner-operators greater clarity and assurance in design and licensing decisions. The LMP employs a team of advanced reactor technology and licensing subject matter experts working closely with U.S. regulators, affected industries, and interested members of the public. The project is managed by Southern Company and supported through a cost share arrangement with DOE. Technical contributions are also provided to the project from the Idaho National Laboratory (INL) Regulatory Development area, the Nuclear Energy Institute (NEI), and the U.S. Nuclear Regulatory Commission (NRC). The LMP identified a suite of high priority issues that provided significant uncertainty within the regulated non-LWR community. It was determined that much of this uncertainty could be retired by issuing updated licensing guidance founded on safety performance demonstrations and modern probabilistic methodologies. The success criteria for the project were established as: • Generate sets of technology inclusive (TI), risk-informed, and performance-based (TI-RIPB) technical requirements, recommendations, and proposals that could be reviewed, amended, and adopted for use by both NRC staff and industry. The proposals would create an optional-use regulatory framework without imposing additional (i.e., mandatory) requirements. • Support LMP the recommended updates of LMP such that they can be finalized, endorsed by NRC, and used by applicants within 5 years. This also supports the DOE advanced- reactor development and deployment goal of completing licensing reviews for technically mature non-LWR concepts sufficient to allow construction to proceed by the early 2030’s. • Further overall programmatic objectives established by DOE’s Gateway for Accelerated Innovation in Nuclear (GAIN) initiative by resolving technology-inclusive policy issues that adversely impact regulatory reviews, siting, permitting, and/or licensing of non-LWRs. This would provide significantly more regulatory certainty for advanced reactor developers.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Key Regulatory Issues in Nuclear Micro-Reactor Transport and Siting
Inherent and passively safe nuclear micro reactors are being developed that feature mobility and autonomous operations much different than the current fleet. Numerous commercial, industrial, and military applications exist for this emerging technology. Challenges in licensing such flexible systems are foreseen, especially in areas related to siting and transport. New assessment approaches will be needed if micro reactors are to realize their full commercial potential while still preserving public safety. This report offers an initial examination of some key regulatory concerns related to micro reactor transport and siting in the continental U.S. Three deployment scenarios were developed to support a regulatory needs analysis concerning the appropriate regulatory structure for the technology, treatment of fueled and unfueled micro reactor modules during transport, and the means by which siting independence can be enhanced. With the exception of certain ultra mobile Department of Defense (DOD) applications, existing statutes suggest the Nuclear Regulatory Commission (NRC) is the appropriate regulatory agency to regulate a domestic commercial micro reactor fleet.
42 ENGINEERING↗
Modernization of Technical Requirements for Licensing of Advanced Non-Light Water Reactors: Selection and Evaluation of Licensing Basis Events
This report, “Modernization of Technical Requirements for Licensing of Advanced Non-Light Water Reactors: Selection and Evaluation of Licensing Basis Events,” represents a key element in the development of a methodology for the efficient licensing of advanced non-light water reactors (non-LWRs). It is the result of a Licensing Modernization Project (LMP) led by Southern Company and cost-shared by the U.S. Department of Energy (DOE). The LMP will result in detailed proposals for establishing licensing technical requirements to facilitate risk-informed and performance-based design and licensing of advanced non-LWRs. Such a methodology acknowledges enhancements in safety achievable with advanced designs and reflects more recent states of knowledge regarding safety and design innovation, creating an opportunity for reduced regulatory complexity with increased levels of safety. The project builds on best practices as well as previous activities through DOE and industry-sponsored advanced reactor licensing initiatives.
42 ENGINEERING↗
Modernization of Technical Requirements for Licensing of Advanced Non-Light Water Reactors: Probabilistic Risk Assessment Approach
This report, “Modernization of Technical Requirements for Licensing of Advanced Non-Light Water Reactors: Probabilistic Risk Assessment Approach,” represents a key element in the development of a methodology for the efficient licensing of advanced non-light water reactors (non-LWRs). It is the result of a Licensing Modernization Project (LMP) led by Southern Company and cost-shared by the U.S. Department of Energy (DOE). The LMP has developed detailed proposals for establishing licensing technical requirements to facilitate risk-informed and performance-based design and licensing of advanced non-LWRs. Such a methodology acknowledges enhancements in safety achievable with advanced designs and reflects more recent states of knowledge regarding safety and design innovation, creating an opportunity for reduced regulatory complexity with increased levels of safety. The project builds on best practices, as well as previous activities through DOE and industry-sponsored advanced reactor licensing initiatives.
42 ENGINEERING↗
Review and Summary of Oxide Thickness Data for Aluminum-Clad Spent Nuclear Fuel
The U.S. Department of Energy (DOE) owns a large inventory of aluminum-clad spent nuclear fuel (ASNF) in interim storage pending ultimate disposition, with more being generated by currently operating research reactors. Dry storage in sealed DOE Standard Canisters is being investigated as an approach for long-term interim storage and/or disposition in a repository for ASNF. A primary challenge for ASNF storage is the presence of aluminum (oxy)hydroxide layers formed on the cladding surfaces during water exposure in the reactor and in wet storage, which forms a reservoir of chemisorbed water not readily removed at low (<100°C) drying temperatures. Free, physisorbed, and chemisorbed water are all susceptible to radiolytic breakdown under irradiation and can release hydrogen gas. Identifying the likely range of (oxy)hydroxide loadings on ASNF that may be placed in dry storage will help to ensure that the impact of the (oxy)hydroxide is adequately accounted for while avoiding over conservatism and enable mitigation strategies to be implemented where needed. The current report summarizes information on (oxy)hydroxide thicknesses and characteristics from the literature and from recent measurements taken in the present research campaign. In general, corrosion studies have indicated that the corrosion and oxide buildup on aluminum are affected by numerous conditions, including pH, temperature and heat flux, coolant flowrates, irradiation (in-reactor vs. unirradiated tests), duration of water exposure, and the amount of oxide already on the surface. Some of these factors are interrelated (e.g., the local temperature, heat flux, and coolant flowrate). Observations of the impact of irradiation (in-reactor versus ex-reactor measurements) on corrosion and oxide thickness are mixed, but multiple studies indicate that there is a significant difference between in-reactor and ex-reactor corrosion kinetics, even when other operating conditions such as pH, flowrate, heat flux, etc., simulate those in a reactor.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Induction plasma heating - System performance, hydrogen operation and gas core reactor simulator development
Induction plasma heating system for hydrogen-argon simulated gas cooled reactor studies
Thorpe, M. L.↗
Monte Carlo calculations of a hemispherical duct neutron streaming experiment
Monte Carlo calculations of hemispherical duct neutron streaming experiment for nuclear reactor shielding design
Clemons, L., Jr.↗
Developmental status of thermionic materials.
Description of the reference materials selected for the major components of the unit cell of a thermionic pile element (TFE), the out-of-pile and in-pile test results, and current efforts for improving the life and performance of thermionic fuel elements. The component materials are required to withstand the fuel burnup and fast neutron fluence dictated by the thermionic reactor system. Tungsten was selected as the cladding material because of its compatibility with both the carbide and the oxide fuel materials. Niobium was selected as the collector material because its thermal expansion coefficient matches closely with that of the thin aluminum oxide layer used to electrically insulate the collector from the TFE sheath. An unfueled converter has performed stably over 41,000 hr. Accelerated irradiation tests have attained burnups equivalent to that for 40,000 hr of the thermionic reactor under consideration.
Yang, L.↗
Nuclear characteristics of a fissioning uranium plasma test reactor with light-water cooling
An analytical study was performed to determine a design configuration for a cavity test reactor. Test section criteria were that an average flux of 10 to the 15th power neutrons/sq cm/sec (E less than or equal to 0.12 eV) be supplied to a 61-cm-diameter spherical cavity at 200-atm pressure. Design objectives were to minimize required driver power, to use existing fuel-element technology, and to obtain fuel-element life of 10 to 100 full-power hours. Parameter calculations were made on moderator region size and material, driver fuel arrangement, control system, and structure in order to determine a feasible configuration. Although not optimized, a configuration was selected which would meet design criteria. The driver fuel region was a cylindrical annular region, one element thick, of 33 MTR-type H2O-cooled elements (Al-U fuel plate configuration), each 101 cm long. The region between the spherical test cavity and the cylindrical driver fuel region was Be (10 vol. % H2O coolant) with a midplane dimension of 8 cm. Exterior to the driver fuel, the 25-cm-thick cylindrical and axial reflectors were also Be with 10 vol. % H2O coolant. The entire reactor was contained in a 10-cm-thick steel pressure vessel, and the 200-atm cavity pressure was equalized throughout the driver reactor. Fuel-element life was 50 hr at the required driver power of 200 MW. Reactor control would be achieved with rotating poison drums located in the cylindrical reflector region. A control range of about 18 percent delta k/k was required for reactor operation.
Whitmarsh, C. L., Jr.↗
Nuclear powerplants for mobile applications.
Mobile nuclear powerplants for applications other than large ships and submarines will require compact, lightweight reactors with especially stringent impact-safety design. This paper examines the technical and economic feasibility that the broadening role of civilian nuclear power, in general, (land-based nuclear electric generating plants and nuclear ships) can extend to lightweight, safe mobile nuclear powerplants. The paper discusses technical experience, identifies potential sources of technology for advanced concepts, cites the results of economic studies of mobile nuclear powerplants, and surveys future technical capabilities needed by examining the current use and projected needs for vehicles, machines, and habitats that could effectively use mobile nuclear reactor powerplants.
Anderson, J. L.↗
Nuclear power plants for mobile applications
Mobile nuclear powerplants for applications other than large ships and submarines will require compact, lightweight reactors with especially stringent impact-safety design. The technical and economic feasibility that the broadening role of civilian nuclear power, in general, (land-based nuclear electric generating plants and nuclear ships) can extend to lightweight, safe mobile nuclear powerplants are examined. The paper discusses technical experience, identifies potential sources of technology for advanced concepts, cites the results of economic studies of mobile nuclear powerplants, and surveys future technical capabilities needed by examining the current use and projected needs for vehicles, machines, and habitats that could effectively use mobile nuclear reactor powerplants.
Anderson, J. L.↗
Design and evaluation of experimental ceramic automobile thermal reactors
The results obtained in an exploratory evaluation of ceramics for automobile thermal reactors are summarized. Candidate ceramic materials were evaluated in several reactor designs by using both engine-dynamometer and vehicle road tests. Silicon carbide contained in a corrugated-metal support structure exhibited the best performance, lasting 1100 hr in engine-dynamometer tests and more than 38,600 km (24000 miles) in vehicle road tests. Although reactors containing glass-ceramic components did not perform as well as those containing silicon carbide, the glass-ceramics still offer good potential for reactor use with improved reactor designs.
Stone, P. L.↗