A Review of Prognostics and Health Management Applications in Nuclear Power Plants

The US operating fleet of light water reactors (LWRs) is currently undergoing life extensions from the original 40-year license to 60 years of operation. In the US, 74 reactors have been approved for the first round license extension, and 19 additional applications are currently under review. Safe and economic operation of these plants beyond 60 years is now being considered in anticipation of a second round of license extensions to 80 years of operation.Greater situational awareness of key systems, structures, and components (SSCs) can provide the technical basis for extending the life of SSCs beyond the original design life and supports improvements in both safety and economics by supporting optimized maintenance planning and power uprates. These issues are not specific to the aging LWRs; future reactors (including Generation III+ LWRs, advanced reactors, small modular reactors, and fast reactors) can benefit from the same situational awareness. In fact, many SMR and advanced reactor designs have increased operating cycles (typically four years up to forty years), which reduce the opportunities for inspection and maintenance at frequent, scheduled outages. Understanding of the current condition of key equipment and the expected evolution of degradation during the next operating cycle allows for targeted inspection and maintenance activities. This article reviews the state of the art and the state of practice of prognostics and health management (PHM) for nuclear power systems. Key research needs and technical gaps are highlighted that must be addressed in order to fully realize the benefits of PHM in nuclear facilities

NDE 4.0—NDE for the 21st Century—The Internet of Things and Cyber Physical Systems will Revolutionize NDE

Challenges and opportunities for NDE within the new ecosystem of cyber physical systems for production, the internet of things and management of Big Data will be discussed. New production techniques, for example 3D printing will allow efficient in-time production of low numbers of unique parts customized for the need of any purchaser. Aspects of NDE reliability and the effect of the human factor has to be reconsidered. New hand-held devices based on tablet computers will be applied to make NDE available and affordable for anybody. As a benefit, product inspection at home can become an additional component of monitoring the life cycle of a product. This might significantly increase the acceptance of NDE by solving new inspection problems for all day service. NDE will revolutionize to NDE 4.0 for Industry 4.

Semi-Annual Report on Work Supporting the International Forum for Reactor Aging Management (IFRAM)

During the first six months of this project, Pacific Northwest National Laboratory has provided planning and leadership support for the establishment of the International Forum for Reactor Aging Management (IFRAM). This entailed facilitating the efforts of the Global Steering Committee to prepare the charter, operating guidelines, and other documents for IFRAM. It also included making plans for the Inaugural meeting and facilitating its success. This meeting was held on August 4 5, 2011, in Colorado Springs, Colorado. Representatives from Asia, Europe, and the United States met to share information on reactor aging management and to 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. On August 4-5, 2011, IFRAM began to achieve its mission. The work completed successfully during this period was built upon important previous efforts. This included the development of a proposal for establishing IFRAM and engaging experts in Asia and Europe. The proposal was 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 report builds on the initial activities and documents the results of activities over the last six months

Physics-Based Prognostics for Optimizing Plant Operation

Scientists at the Pacific Northwest National Laboratory (PNNL) have examined the necessity for optimization of energy plant operation using 'DSOM{reg_sign}'--Decision Support Operation and Maintenance and this has been deployed at several sites. This approach has been expanded to include a prognostics components and tested on a pilot scale service water system, modeled on the design employed in a nuclear power plant. A key element in plant optimization is understanding and controlling the aging process of safety-specific nuclear plant components. This paper reports the development and demonstration of a physics-based approach to prognostic analysis that combines distributed computing, RF data links, the measurement of aging precursor metrics and their correlation with degradation rate and projected machine failure

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

Higher Order Acoustoelastic Lamb Wave Propagation in Stressed Plates

Residual stresses can be generated during fabrication processes, such as, welding, forging, rolling etc[1-3] . They have obvious influence on the performance of the material, like cracking and corrosion. To better control residual stresses, the initial distribution of them in materials must be clear. Ultrasonic methods can be used as a good tool for residual stress detection, and this approach is non-destructive and costs are modest. Methods which utilize longitudinal critically refracted (LCR) waves are receiving increased attention and it can be used on thick material. However, there have only been a limited number of studies which consider the acoustoelastic effect for thin plate materials which generate Lamb waves[4] . This paper reports a study in which a numerical model[5-6] is used to investigate the Lamb wave dispersion curves under loading that induce stresses. The effects of stress on various Lamb modes are discussed and those which appear to be most sensitive are identified. It is found that when the stress’s direction is the same with wave propagation direction in a 1 mm thick aluminum plate the A0 mode is the most sensitive to the applied stress

An Intermediate Luminosity Transient in NGC300: The Eruption of a Dust-Enshrouded Massive Star

[abridged] We present multi-epoch high-resolution optical spectroscopy, UV/radio/X-ray imaging, and archival Hubble and Spitzer observations of an intermediate luminosity optical transient recently discovered in the nearby galaxy NGC300. We find that the transient (NGC300 OT2008-1) has a peak absolute magnitude of M_bol~-11.8 mag, intermediate between novae and supernovae, and similar to the recent events M85 OT2006-1 and SN2008S. Our high-resolution spectra, the first for this event, are dominated by intermediate velocity (~200-1000 km/s) hydrogen Balmer lines and CaII emission and absorption lines that point to a complex circumstellar environment, reminiscent of the yellow hypergiant IRC+10420. In particular, we detect broad CaII H&K absorption with an asymmetric red wing extending to ~1000 km/s, indicative of gas infall onto a massive and relatively compact star (blue supergiant or Wolf-Rayet star); an extended red supergiant progenitor is unlikely. The origin of the inflowing gas may be a previous ejection from the progenitor or the wind of a massive binary companion. The low luminosity, intermediate velocities, and overall similarity to a known eruptive star indicate that the event did not result in a complete disruption of the progenitor. We identify the progenitor in archival Spitzer observations, with deep upper limits from Hubble data. The spectral energy distribution points to a dust-enshrouded star with a luminosity of about 6x10^4 L_sun, indicative of a ~10-20 M_sun progenitor (or binary system). This conclusion is in good agreement with our interpretation of the outburst and circumstellar properties. The lack of significant extinction in the transient spectrum indicates that the dust surrounding the progenitor was cleared by the outburst.Comment: Submitted to ApJ; emulateapj style; 39 pages; 26 figure

Proactive Management of Materials Degradation - A Review of Principles and Programs

The U.S. Nuclear Regulatory Commission (NRC) has undertaken a program to lay the technical foundation for defining proactive actions so that future degradation of materials in light water reactors (LWRs) is limited and, thereby, does not diminish either the integrity of important LWR components or the safety of operating plants. This technical letter report was prepared by staff at Pacific Northwest National Laboratory in support of the NRC Proactive Management of Materials Degradation (PMMD) program and relies heavily on work that was completed by Dr. Joseph Muscara and documented in NUREG/CR-6923. This report concisely explains the basic principles of PMMD and its relationship to prognostics, provides a review of programs related to PMMD being conducted worldwide, and provides an assessment of the technical gaps in PMMD and prognostics that need to be addressed. This technical letter report is timely because the majority of the U.S. reactor fleet is applying for license renewal, and many plants are also applying for increases in power rating. Both of these changes could increase the likelihood of materials degradation and underline, therefore, the interest in proactive management in the future