Research in Nondestructive Evaluation Techniques for Nuclear Reactor Concrete Structures
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Concrete↗
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Comparative Testing of Nondestructive Examination Techniques for Concrete Structures
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concrete↗
Recent Advances in Understanding Radiation Damage in Reactor Cavity Concrete
License renewal up to 60 years and the possibility of subsequent license renewal to 80 years has resulted in a renewed focus on long-term aging of materials at nuclear power plants (NPPs) including concrete. Large irreplaceable sections of most nuclear generating stations include concrete. The Expanded Materials Degradation Analysis, jointly performed by the Department of Energy, the Nuclear Regulatory Commission and Nuclear Industry, identified the urgent need to develop a consistent knowledge base on irradiation effects in concrete (Graves et al., (2014)). Much of the historical mechanical performance data of irradiated concrete (Hilsdorf et al., (1978)) does not accurately reflect typical radiation conditions in NPPs or conditions out to 60 or 80 years of radiation exposure (Kontani et al., (2011)). To address these potential gaps in the knowledge base, the Electric Power Research Institute and Oak Ridge National Laboratory, are working to better understand radiation damage as a degradation mechanism. This paper outlines recent progress toward: 1) assessing the radiation environment in concrete biological shields and defining the upper bound of the neutron and gamma dose levels expected in the biological shield for extended operation, and estimating adsorbed dose, 2) evaluating opportunities to harvest and test irradiated concrete from international NPPs, 3) evaluating opportunities to irradiate prototypical concrete and its components under accelerated neutron and gamma dose levels to establish conservative bounds and inform damage models, 4) developing improved models to enhance the understanding of the effects of radiation on concrete and 5) establishing an international collaborative research and information exchange effort to leverage capabilities and knowledge including developing cooperative test programs to improve confidence in data obtained from various concretes and from accelerated irradiation experiments.
Cocrete Bioshield↗
FY 2017 Stockpile Stewardship and Management Plan - Biennial Plan Summary
This year’s summary report updates the Fiscal Year 2016 Stockpile Stewardship and Management Plan (FY 2016 SSMP), the 25-year strategic program of record that captures the plans developed across numerous NNSA programs and organizations to maintain and modernize the scientific tools, capabilities, and infrastructure necessary to ensure the success of NNSA’s nuclear weapons mission. The SSMP is a companion to the Prevent, Counter, and Respond: A Strategic Plan to Reduce Global Nuclear Threats (FY 2017-2021) report, the planning document for NNSA’s nuclear threat reduction mission. New versions of both reports are published each year in response to new requirements and challenges. Much was accomplished in FY 2015 as part of the program of record described in this year’s SSMP. The science-based Stockpile Stewardship Program allowed the Secretaries of Energy and Defense to certify for the twentieth time that the stockpile remains safe, secure, and effective without the need for underground nuclear explosive testing. The talented scientists, engineers, and technicians at the three national security laboratories, the four nuclear weapons production plants, and the national security site are primarily responsible for this continued success. Research, development, test, and evaluation programs have advanced NNSA’s understanding of weapons physics, component aging, and material properties through first-of-a-kind shock physics experiments, along with numerous other critical experiments conducted throughout the nuclear security enterprise. The multiple life extension programs (LEPs) that are under way made progress toward their first production unit dates. The W76-1 LEP is past the halfway point in total production, and the B61-12 completed three development flight tests. Critical to this success is the budget. The Administration’s budget request for NNSA’s Weapons Activities has increased for all but one of the past seven years, resulting in a total increase of approximately 45 percent since 2010. If adopted by Congress, the FY 2017 budget request will increase funding by $396 million (about 4.5 percent) from the enacted FY 2016 level. A significant portion of the increase would fund the research for multiple life extension programs, support the programs in Directed Stockpile Work, and modernize the physical infrastructure of the nuclear security enterprise.
Source record↗
Characterization of Aging and Degradation of Reactor Materials in Extreme Environments.
Abstract not provided.
Herrmann, Christian↗
Thermoelectric materials and devices: characterization reliability aging.
Abstract not provided.
Sharma, Peter Anand↗
LWRS Year End Report - Cable Aging Research at SNL Organic Materials Science Department.
Abstract not provided.
Bernstein, Robert↗
Dimensional-stability studies of candidate space-telescope mirror-substrate materials
The effects of aging, vacuum exposure, and thermal cycling on the dimensional stability of mirror-substrate materials, fused silica, Cer-Vit, Kanigen-coated beryllium, polycrystalline silicon, and U.L.E. fused silica were investigated. A multiple-beam interferometer was used to determine nonrecoverable surface-shape changes of the 12.7-cm-diameter mirrors with substrates of these materials. Thermal cycling and aging in vacuum produced the largest changes, but only a few were as large as 1/30 wavelength, where the wavelength was 632.8 nm.
Jerke, J. M.↗
Experimental Characterization of Hygrothermal Aging: Competition Between Thermo-Oxidation and Hydrolysis Phenomena
Abstract In this work, we have presented a comparison between effects of accelerated thermo-oxidative, hydrolytic and hygrothermal aging on the mechanical and chemical properties of a polyurethane based (PUB) adhesive. The adhesive is a flexible adhesive which is extensively used in automobile industry as a glass sealant. During service life it gets exposed to the hygrothermal environment and the integrity of matrix interface is most vulnerable. This study focuses on weighing and comparing effects of different aging environments on material behavior; and it shows that hygrothermal aging environment results as a competition between two sub-aging phenomena i.e., thermo-oxidation and hydrolytic aging. Samples were exposed to 0%RH, 80%RH and submerged condition in distilled water. Uni-axial tensile tests, and cross-link density analysis by swelling test were carried out on as-received and aged samples. The aging process was conducted at three different temperatures (60°C, 80°C and 95°C) and for four different exposure durations of 1, 10, 30, and 90 days. This work confirms that the effect of hygrothermal aging is a result of competition between thermo-oxidation and hydrolytic aging environments. The total mechanical and environmental damage incurred by specimens is a collaborative effect of all exposure environments involved i.e., aging time, temperature, oxygen, water and humidity. The results are in agreement with the chemical test outcomes as well.
Shaafaey, Mamoon↗
Effect of directed aging on nonlinear elasticity and memory formation in a material
Disordered solids often change their elastic response as they slowly age. Using experiments and simulations, we study how aging disordered planar networks under an applied stress affects their nonlinear elastic response. We are able to modify dramatically the elastic properties of our systems in the nonlinear regime. Using simulations, we study two models for the microscopic evolution of properties of such a material; the first considers changes in the material strength, while the second considers distortions in the microscopic geometry. Both models capture different aspects of the experiments including the encoding of memories of the aging history of the system and the dramatic effects on the material’s nonlinear elastic properties. Our results demonstrate how aging can be used to create complex elastic behavior in the nonlinear regime.
36 MATERIALS SCIENCE↗
Physical aging and solvent effects on the fracture of LaRC-TPI adhesives
When amorphous materials are quenched below their glass transition temperature, excess enthalpy is trapped in the glassy material because the viscosity is too great to allow the material to remain in volumetric equilibrium. Over time, this excess free volume is reduced as the material slowly approaches its equilibrium configuration. This process, known as physical aging, leads to substantial changes in the constitutive behavior of polymers, as has been widely discussed in the literature. Less is known about the effects of this physical aging process on fracture and fatigue properties of aged materials. The original goal of the summer was to investigate the effects of physical aging on the fracture and fatigue behavior of LaRC-TPI, a thermoplastic polyimide developed at NASA-Langley. Preliminary results are reported, although a lack of equipment availability prevented completion of this task. In the process of making specimens, the current LaRC-TPI was observed to be extremely susceptible to environmental stress cracking. A study of the unique failure patterns resulting from this degradation process in bonded joints was conducted and is also reported herein.
Dillard, David A.↗
Developing rapid electrochemical relithiation protocols for scalable relithiation of lithium-ion battery cathode materials
The recent and ongoing boom in electric vehicle sales has caused the circularity of the supply chain for electric vehicle battery materials to come under a great deal of scrutiny. Innovative recycling processes, or direct recycling, that offer the possibility of reducing the cost of recycling are one possible solution to regaining resources from end-of-life (EoL) electric vehicle batteries. Electrochemically shuttling lithium back into the cathode, or electrochemical relithiation, is a possible technique for restoring lithium content to NMC materials (EoL) in a direct recycling process. This study provides essential understanding towards developing an electrochemical relithiation protocol that will restore lithium loss in intercalation cathode materials that reach EoL by loss of lithium inventory (LLI) as opposed to other degradation mechanisms like loss of active material (LAM), cation mixing or phase transition. Electrochemically aged NMC cathode materials have been prepared and characterized to establish the extent of EoL material structural degradation and lithium loss. A model-informed experimental process is used to identify the optimal electrochemical relithiation protocol to minimize the time taken to relithiate EoL materials and maximize the amount of lithium restored. Protocols were evaluated based on their ability to enable rapid lithium intercalation, maintain structural uniformity in the EoL material and fully restore lithium content. An optimal protocol was identified at elevated temperatures utilizing a novel scanning voltage step.
25 ENERGY STORAGE↗
Material Testing Device
Small Business Innovation Research (SBIR) contracts led to two commercial instruments and a new subsidiary for Physical Sciences, Inc. (PSI). The FAST system, originally developed for testing the effect of space environment on materials, is now sold commercially for use in aging certification of materials intended for orbital operation. The Optical Temperature Monitor was designed for precise measurement of high temperatures on certain materials to be manufactured in space. The original research was extended to the development of a commercial instrument that measures and controls fuel gas temperatures in industrial boilers. PSI created PSI Environmental Instruments to market the system. The company also offers an Aerospace Measurement Service that has evolved from other SBIR contracts.
Source record↗
Proceedings of the Inaugural Meeting of the International Forum for Reactor Aging Management (IFRAM)
In almost all countries with nuclear power plants (NPPs), regulatory authorities and the nuclear industry are looking at some form of extended operating periods. To support life extension activities it is necessary to ensure the continued safety and reliability of system, structures, and components, and the component materials. Internationally, a variety of individual national and international activities have been initiated including Plant Life Management through the International Atomic Energy Agency, Electric Power Research Institute’s Long Term Operation program, and various national programs in managing materials degradation and related topics. The U.S. Nuclear Regulatory Commission (NRC) engaged the international community in workshops in 2005-2006 to identify research needs and to collect information in an expert panel report on Proactive Management of Materials Degradation (PMMD), which was reported in NUREG/CR-6923. These results are also available via an Information Tool on the internet at http://pmmd.pnl.gov. This information builds on the extensive compilations known as the GALL Report (Generic Aging Lessons Learned, NUREG-1801, Vols. 1 and 2). Pacific Northwest National Laboratory (PNNL) recently issued a report on the review of various international activities in PMMD (PNNL-17779). There have also been initiatives by Electricite de France, Tokyo Electric Power Company, EPRI, and others to establish a "Materials Aging Institute." Within the materials degradation research community there are also networks and technical meetings focused on some elements of PMMD. In spite of all these efforts, there is currently no forum to bring together these diverse activities and provide coordinated information exchange and prioritization of materials aging management/PMMD topics. It is believed that the International Forum for Reactor Aging Management (IFRAM) would be a good way to achieve this goal and help develop new approaches for ensuring continued safe operation in existing and future nuclear power plants. To begin addressing this need, NRC has established a Proactive Management of Materials Degradation Program for managing in-service degradation of metallic components in aging NPPs. The NRC is seeking to facilitate the establishment of IFRAM as a network of international experts who would exchange information on operating experience, best practices, and emerging knowledge. These experts would be willing to work jointly and leverage the separate efforts of existing national programs into a unified approach to enable the potential for the safe and economic life extension of NPPs. A proposal for establishing IFRAM was developed and presented at Engagement workshops in Seoul, Korea (October 2009) and Petten, The Netherlands (May 2010). Participants in both groups demonstrated strong interest in the establishment of IFRAM. Therefore the Global Steering Committee was formed to plan and carry out the start-up of IFRAM in 2011. This group finalized the documents for IFRAM and organized the kick-off meeting. This document records the contents of the inaugural meeting of IFRAM, which was held August 4-5, 2011, at the Cheyenne Mountain Resort in Colorado Springs, Colorado. Representatives from Asia, Europe, and the United States met to share information on reactor aging management and make plans for the future. Professor Tetsuo Shoji was elected chairperson of the Leadership Council. This kick-off event transformed the dream of an international forum into a reality. IFRAM has begun to achieve its mission.
Reactor Aging Management↗
Age and provenance of the target materials for tektites and possible impactites as inferred from Sm-Nd and Rb-Sr systematics
Chemical, trace element, and isotopic compositions of tektites are consistent with production by melting of sediments derived from the old terrestrial continental crust. Each tektite group is characterized by a uniform Nd model age, interpreted as the time of formation of the crustal segment which weathered to form the parent sediment for the tektites. Sr model ages are variable within each group, reflecting Rb-Sr fractionation, and, in the favorable limit of very high Rb/Sr ratios, approach the time of sedimentation of the parent material which melted to form the tektites. Unlike tektites, which are dense homogeneous objects, sanidine spherules are porous, fine grained inhomogeneous objects. The leaching experiment employed by the present study shows that the sanidine spherules could have been formed by an oceanic impact involving basaltic crust and overlying sediments or seawater.
Shaw, H. F.↗
Radiation-induced aging of PDMS Elastomer TR-55: a summary of constitutive, mesoscale, and population-based models
Filled and cross-linked elastomeric rubbers are versatile network materials with a multitude of applications ranging from artificial organs and biomedical devices to cushions, coatings, adhesives, interconnects, and seismic-isolation-, thermal-, and electrical barriers. External factors like mechanical stress, temperature fluctuations, or radiation are known to create chemical changes in such materials that can directly affect the molecular weight distribution (MWD) of the polymer between cross-links and alter the structural and mechanical properties. From a Materials Science point of view it is highly desirable to understand, effect, and manipulate such property changes in a controlled manner. In this report we summarize our modeling efforts on a polysiloxane elastomer TR-55, which is an important component in several of our systems, and representative of a wide class of filled rubber materials. The primary aging driver in this work has been γ-radiation, and a variety of modeling approaches have been employed, including constitutive, mesoscale, and population-based models. The work utilizes diverse experimental data, including mechanical stress-strain and compression set measurements, as well as MWD measurements using multiquantum NMR.
36 MATERIALS SCIENCE↗
An interlaboratory collaboration to determine consensus 231 Pa/ 235 U model ages of a uranium certified reference material for nuclear forensics
Application of the 231 Pa/ 235 U radiochronometer for nuclear forensic investigations is challenged by a lack of certified reference materials with 231 Pa/ 235 U model purification dates. The Japan Atomic Energy Agency, Los Alamos National Laboratory, and Lawrence Livermore National Laboratory completed an interlaboratory study measuring 231 Pa/ 235 U model ages of New Brunswick Laboratory CRM U100. Results from independent laboratories were combined to calculate a consensus 231 Pa/ 235 U model purification date for CRM U100 of March 26, 1959 ± 237 days. This 231 Pa/ 235 U consensus date for CRM U100 may be used by the nuclear forensic community for quality control of 231 Pa/ 235 U radiochronometry measurements of unknown materials.
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
The Evolving Chronology of Moon Formation
Defining the age of the Moon has proven to be an elusive task because it requires reliably dating lunar samples using radiometric isotopic systems that record fractionation of parent and daughter elements during events that are petrologically associated with planet formation. Crystallization of the magma ocean is the only event that unambiguously meets this criterion because it probably occurred within tens of millions of years of Moon formation. There are three dateable crystallization products of the magma ocean: mafic mantle cumulates, felsic crustal cumulates, and late-stage crystallization products known as urKREEP (uniform residuum K, rare earth elements, and P). Although ages for these materials in the literature span 200 million years, there is a preponderance of reliable ages around 4.35 billion years recorded in all three lunar rock types. This age is also observed in many secondary crustal rocks, indicating that they were produced contemporaneously (within uncertainty of the ages), possibly during crystallization and overturn of the magma ocean. •The duration of planet formation is key information in understanding the mechanisms by which the terrestrial planets formed. •Ages of the oldest lunar rocks range widely, reflecting either the duration of Moon formation or disturbed ages caused by impact metamorphism. •Ages determined for compositionally distinct crust and mantle materials produced by lunar magma ocean differentiation cluster near 4.35 Gyr. •The repeated occurrence of 4.35 Gyr ages implies that Moon formation occurred late in Solar System history, likely by giant impact into Earth.
79 ASTRONOMY AND ASTROPHYSICS↗