Engineering topics

Bond, Leonard J

Publications and source records attributed to Bond, Leonard J.

13 records

DOE OSTI2012

Materials Issues in High Temperature Ultrasonic Transducers for Under-Sodium Viewing

Liquid sodium is used as the coolant in some fast spectrum nuclear reactors. This material is optically opaque. To facilitate operations and maintenance activities, an ultrasonic under-sodium viewing system has been developed. In the USA, the technology was successfully demonstrated in the 1970's, and, over the intervening 30+ years the capability was lost. This paper reports materials challenges encountered in developing both single-element and linear phased array 2 MHz transducers that must operate at temperatures up to 260C. The critical issues are fundamentally material selection: the ability of a transducer to be immersed into liquid sodium and function at 260C, to achieve wetting and transmission of ultrasound into the sodium, and to be able to be removed and re-used.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

DOE OSTI2012

Online Condition Monitoring to Enable Extended Operation of Nuclear Power Plants

Safe, secure, and economic operation of nuclear power plants will remain of strategic significance. New and improved monitoring will likely have increased significance in the post-Fukushima world. Prior to Fukushima, many activities were already underway globally to facilitate operation of nuclear power plants beyond their initial licensing periods. Decisions to shut down a nuclear power plant are mostly driven by economic considerations. Online condition monitoring is a means to improve both the safety and economics of extending the operating lifetimes of nuclear power plants, enabling adoption of proactive aging management. With regard to active components (e.g., pumps, valves, motors, etc.), significant experience in other industries has been leveraged to build the science base to support adoption for online condition-based maintenance and proactive aging management in the nuclear industry. Many of the research needs are associated with enabling proactive management of aging in passive components (e.g., pipes, vessels, cables, containment structures, etc.). This paper provides an overview of online condition monitoring for the nuclear power industry with an emphasis on passive components. Following the overview, several technology/knowledge gaps are identified, which require addressing to facilitate widespread online condition monitoring of passive components.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2011

High Temperature Ultrasonic Transducers for In-Service Inspection of Liquid Metal Fast Reactors

In-service inspection of liquid metal (sodium) fast reactors requires the use of ultrasonic transducers capable of operating at high temperatures (>200°C), high gamma radiation fields, and the chemically reactive liquid sodium environment. In the early- to mid-1970s, the U.S. Atomic Energy Commission supported development of high-temperature, submersible single-element transducers, used for scanning and under-sodium imaging in the Fast Flux Test Facility and the Clinch River Breeder Reactor. Current work is building on this technology to develop the next generation of high-temperature linear ultrasonic transducer arrays for under-sodium viewing and in-service inspections.

Fast Reactors↗

DOE OSTI2011

Prognostics and Life Beyond 60 Years for Nuclear Power Plants

Safe, secure, reliable and sustainable energy supply is vital for advanced and industrialized life styles. To meet growing energy demand there is interest in longer term operation (LTO) for the existing nuclear power plant fleet and enhancing capabilities in new build. There is increasing use of condition based maintenance (CBM) for active components and growing interest in deploying on-line monitoring instead of periodic in service inspection (ISI) for passive systems. Opportunities exist to move beyond monitoring and diagnosis based on pattern recognition and anomaly detection to prognostics with the ability to provide an estimate of remaining useful life (RUL). The adoption of digital I&C systems provides a framework within which added functionality including on-line monitoring can be deployed, and used to maintain and even potentially enhance safety, while at the same time improving planning and reducing both operations and maintenance costs.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2011

Ultrasonics: Fundamentals, Technologies, and Applications

This is a new edition of a bestselling industry reference. Discusses the science, technology, and applications of low and high power ultrasonics, including industrial implementations and medical uses. Reviews the basic equations of acoustics, starting from basic wave equations and their applications. New material on property determination, inspection of metals (NDT) and non-metals, imaging, process monitoring and control. Expanded discussion of transducers, transducer wave-fields, scattering, attenuation and measurement systems and models. New material that discusses high power ultrasonics - in particular using mechanical effects and sonochemistry, including applications to nano-materials. Examines diagnosis, therapy, and surgery from a technology and medical physics perspective.

99 GENERAL AND MISCELLANEOUS↗

DOE OSTI2011

Online Monitoring To Enable Improved Diagnostics, Prognostics and Maintenance

Only time will tell what the implications of the Fukushima incident will be. Discussions are on-going with regard to continued operation and life extension of the existing fleet, new build, and the wider policy issues including technologies needed to address spent fuel storage and ensure energy security, and the related desires to provide sustainable energy systems while at the same time limiting greenhouse gas emissions. The science base for advanced diagnostics and prognostics to support its use in nuclear power plants (NPPs) for active components (pumps, valves etc) has been demonstrated. A challenge is enabling adaption of these technologies for NPP deployment and the validation of the data from these technologies. Advanced diagnostics, monitoring and prognostics applied to passive structures, which in the USA context of longer term operation is up to 80 years, are being researched. Early laboratory work is demonstrating the potential for these methods, although technical challenges remain. It can be expected that there will be an increased need for and use of on-line monitoring for a wide range of both active and passive systems in all types of nuclear power plants.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2011

Methods for the In-Situ Characterization of Cast Austenitic Stainless Steel Microstructures

Cast austenitic stainless steel (CASS) that was commonly used in U.S. nuclear power plants is a coarse-grained, elastically anisotropic material. Its engineering properties made it a material of choice for selected designs of nuclear power reactor systems. However, the fabrication processes result in a variety of coarse-grain microstructures that make current ultrasonic in-service inspection of components quite challenging. To address inspection needs, new ultrasonic inspection approaches are being sought. However, overcoming the deleterious and variable effects of the microstructure on the interrogating ultrasonic beam may require knowledge of the microstructure, for potential optimization of inspection parameters to enhance the probability of detection (POD). The ability to classify microstructure type (e.g. polycrystalline or columnar) has the potential to guide selection of optimal NDE approaches. This paper discusses the application of ultrasonic and electromagnetic methods for classifying CASS microstructures, when making measurements from the outside surface of the component. Results to date demonstrate the potential of these measurements to discriminate between two consistent microstructures - equiaxed-grain material versus columnar-grain material. The potential for fusion of ultrasonic and electromagnetic measurements for in-situ microstructure characterization in CASS materials will be explored.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2011

Prognostics and Life Beyond 60 for Nuclear Power Plants

Safe, secure, reliable and sustainable energy supply is vital for advanced and industrialized life styles. To meet growing energy demand there is interest in longer term operation (LTO) for the existing nuclear power plant fleet and enhancing capabilities in new build. There is increasing use of condition based maintenance (CBM) for active components and periodic in service inspection (ISI) for passive systems: there is growing interest in deploying on-line monitoring. Opportunities exist to move beyond monitoring and diagnosis based on pattern recognition and anomaly detection to and prognostics with the ability to provide an estimate of remaining useful life (RUL). The adoption of digital I&C systems provides a framework within which added functionality including on-line monitoring can be deployed, and used to maintain and even potentially enhance safety, while at the same time improving planning and reducing both operations and maintenance costs.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

DOE OSTI2011

Acoustic Emission and Guided Wave Monitoring of Fatigue Crack Growth on a Full Pipe Specimen

Continuous on-line monitoring of active and passive systems, structures and components in nuclear power plants will be critical to extending the lifetimes of nuclear power plants in the US beyond 60 years. Acoustic emission and guided ultrasonic waves are two tools for continuously monitoring passive systems, structures and components within nuclear power plants and are the focus of this study. These tools are used to monitor fatigue damage induced in a SA 312 TP304 stainless steel pipe specimen. The results of acoustic emission monitoring indicate that crack propagation signals were not directly detected. However, acoustic emission monitoring exposed crack formation prior to visual confirmation through the detection of signals caused by crack closure friction. The results of guided ultrasonic wave monitoring indicate that this technology is sensitive to the presence and size of cracks. The sensitivity and complexity of GUW signals is observed to vary with respect to signal frequency and path traveled by the guided ultrasonic wave relative to the crack orientation.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2011

Damage Assessment Technologies for Prognostics and Proactive Management of Materials Degradation

The Nuclear Regulatory Commission has undertaken a program to lay the groundwork for defining proactive actions to manage degradation of materials in light water reactors (LWRs). This paper discusses the U.S. Nuclear Regulatory Commission’s Proactive Management of Materials Degradation (PMMD) program and its application to nuclear power plant structures, systems and components. The PMMD program is examining LWR component materials and the degradation phenomena that affect them. Of particular interest is how such phenomena can be monitored to predict degradation and prevent component failure. Some forms of degradation, such as stress corrosion cracking, are characterized by a long initiation time followed by a rapid growth phase. Monitoring such long-term degradation will require new NDE methods and measurement procedures. A critical analysis of all reactor components is required to determine if new inspection strategies are required to effectively manage slow degradation mechanisms that may lead to component failure. As reactor lifetimes are extended, degradation mechanisms previously considered too long-term to be of consequence (such as concrete and wiring insulation degradation) may become more important. This paper includes a review of techniques with potential for sensing and monitoring degradation in its early stages and will concisely explain the basic principles of PMMD and its relationship to in-service inspection, condition based maintenance, and advanced diagnostics and prognostics.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2011

Proactive Degradation Management

Robust growth in the nuclear power industry is anticipated as surging global demand for electricity converges with the desire to minimize carbon emissions. There are currently 439 nuclear power plants (NPP) in the commercial global fleet and by some estimates another 222 projects are in various stages of development. For both existing and new plant designs there are increasing needs for the application of advanced online surveillance, diagnostic and prognostic techniques to continuously monitor and assess the health of NPP systems and components. The added effectiveness of such programs has the potential to enable holistic plant management, and minimize exposure to future and unknown risks. This article makes the case for the use of a prognostic approach.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2011

Online Monitoring to Enable Improved Diagnostics, Prognostics and Maintenance

For both existing and new plant designs there are increasing opportunities and needs for the application of advanced online surveillance, diagnostic and prognostic techniques. These methods can continuously monitor and assess the health of nuclear power plant systems and components. The added effectiveness of such programs has the potential to enable holistic plant management, and minimize exposure to future and unknown risks. The 'NDE & On-line Monitoring' activities within the Advanced Instrumentation, Information and Control Systems (II&CS) Pathway are developing R&D to establish advanced condition monitoring and prognostics technologies to understand and predict future phenomena, derived from plant aging in systems, structures, and components (SSC). This research includes utilization of the enhanced functionality and system condition awareness that becomes available through the application of digital technologies at existing nuclear power plants for online monitoring and prognostics. The current state-of-the-art for on-line monitoring applied to active components (eg pumps, valves, motors) and passive structure (eg core internals, primary piping, pressure vessel, concrete, cables, buried pipes) is being reviewed. This includes looking at the current deployment of systems that monitor reactor noise, acoustic signals and vibration in various forms, leak monitoring, and now increasingly condition-based maintenance (CBM) for active components. The NDE and on-line monitoring projects are designed to look beyond locally monitored CBM. Current trends include centralized plant monitoring of SSC, potential fleet-based CBM and technology that will enable operation and maintenance to be performed with limited on-site staff. Attention is also moving to systems that use online monitoring to permit longer term operation (LTO), including a prognostic or predictive element that estimates a remaining useful life (RUL). Many, if not all, active components (pumps, valves, motors etc.) can be well managed, routinely diagnosed, analyzed and upgraded as needed using a combination of periodic and online CBM. The ability to successfully manage passive systems and structures is seen as the key to LTO, particularly in the USA. New approaches will be demonstrated, including prognostics for passive structures, which is critical to maintaining safety and availability and to reducing operations and maintenance costs for NPP's. To provide proactive on-line monitoring that includes estimates for RUL new projects will include advanced sensors, better understanding of stressors and challenges faced in quantification of uncertainty associated with RUL. This program area will leverage insights from past experience in other industries and seek to demonstrate the feasibility of on-line monitoring and prognostics to support NPP LTO.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2010

In-situ Characterization of Cast Stainless Steel Microstructures

Cast austenitic stainless steel (CASS) that was commonly used in U.S. nuclear power plants is a coarse-grained, elastically anisotropic material. The engineering properties of CASS made it a material of choice for selected designs of nuclear power reactor systems. However, the fabrication processes result in a variety of coarse-grain microstructures that are difficult to inspect ultrasonically, largely due to detrimental effects of wave interactions with the microstructure. To address the inspection needs, new approaches that are robust to these phenomena are being sought. However, overcoming the deleterious effects of the coarse-grained microstructure on the interrogating ultrasonic beam will require knowledge of the microstructure and the corresponding acoustic properties of the material, for potential optimization of inspection parameters to enhance the probability of detecting flaws. The goal of improving the reliability and effectiveness of ultrasonic inspection of CASS specimens can therefore potentially be achieved by first characterizing the microstructure of the component. The characterization of CASS microstructure must be done in-situ, to enable dynamic selection and optimization of the ultrasonic inspection technique. This paper discusses the application of ultrasonic measurement methods for classifying the microstructure of CASS components, when making measurements from the outside surface of the pipe or component. Results to date demonstrate the potential of ultrasonic and electromagnetic measurements to classify the material type of CASS for two consistent microstructures-equiaxed-grain material and columnar-grain material.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗