New Approach for Fatigue Damage Monitoring Based on Actual Operating History of Nuclear Power Plants

The Sodium Fast-cooled Reactor (SFR), are generation IV nuclear power plants, have a target operating temperature of 550°C which makes creep-fatigue behavior more critical than a generation III nuclear power plants. So it is important to understand the nature of creep-fatigue behavior of the piping material, Grade 91 steel. The creep-fatigue damage diagram of Grade 91 steel used in ASME-NH was derived using a conventional time-fraction testing method which was originally developed for type 300 stainless steels. Multiple studies indicate that the creep-fatigue damage diagram of Grade 91 steel developed using this testing method has excessive conservatism in it. Therefore, an alternative testing method was suggested by separating creep and fatigue using interrupted creep tests. The suggested method makes it possible to control creep life consumption freely which was difficult with the previous method. It also makes it easier to observe the interaction between creep and fatigue mechanisms and microstructural evolution. In conclusion, an alternative creep-fatigue damage diagram for Grade 91 steel at 550°C was developed using an interrupt creep fatigue testing method and FE model simulation.

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Efficiency and prospects for the implementation of measures for qualification of equipment important for safety in domestic nuclear energetics

Nuclear Physics and Atomic Energy ◽

10.15407/jnpae2020.04.369 ◽

2020 ◽

Vol 21 (4) ◽

pp. 369-377

Author(s):

I.A. Khomych ◽

◽

T.V. Kovalinska ◽

V.I. Sakhno ◽

Yu.V. Ivanov

Keyword(s):

Nuclear Power ◽

Power Plants ◽

Nuclear Power Plants ◽

Expected Time ◽

Operating Modes ◽

Reliability Indicators ◽

Before And After ◽

Operational Information ◽

History Of ◽

On Line

The results of implementing equipment qualification are analyzed. Such equipment is critical for the nuclear and technical safety of domestic nuclear power plants that are especially important for the implementation of the Program for extending the terms of out-of-project operation of power reactors that are capable of being used as powerful sources of electricity. Based on the comparison of published reliability indicators of domestic nuclear power plants before and after implementing the qualification, it is shown that still there are problems to be solved. The perspective of further enhancing the reliability of the operation of domestic nuclear energetics is considered, by implementing radiation functional testing methods that are been developed at the INR NAS of Ukraine for a long period. The basis of this method is detailed research and operational control of all processes that occur in critical equipment in any operating modes of nuclear reactors to form a resource history of the equipment and to provide operational information about the remaining resource and the expected time of its failure to an on-line object operator.

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Complex Low-Cycle Fatigue Damage Assessment of Components and Piping of Nuclear Power Plants Type WWER

Volume 1A: Codes and Standards ◽

10.1115/pvp2017-65257 ◽

2017 ◽

Author(s):

Libor Vlcek ◽

Lubomir Junek

Keyword(s):

Fatigue Damage ◽

Nuclear Power ◽

Power Plants ◽

Nuclear Power Plants ◽

Low Cycle Fatigue ◽

Life Assessment ◽

Design Stage ◽

Multiaxial Loading ◽

Cycle Fatigue ◽

Mathematical Formulas

An innovative principle of low-cycle fatigue (LCF) life assessment suggested for WWER nuclear power plants is presented. In the design stage the fatigue life assessment is based on fatigue design curves, which are introduced in graphical form for air environment. Alternatively and especially for operational stage the fatigue curves are constructed on the basis of mathematical formulas. Mathematical descriptions were validated by strain-controlled LCF laboratory tests. Due to such validated mathematical formulas the complex LCF damage analyses of nuclear power plant components and piping are enabled. In the frame of complex LCF assessment the influence of operating temperatures, stress asymmetry ratio, corrosion environment, neutron fluency and multiaxial loading can be taken into account not only for the base steel materials, but also for their welds. The aim of this paper is to summarise the whole methodology of complex LCF assessment and damage prediction including operational limits of fatigue damage defined in the Czech nuclear standard. The innovation process of original Russian LCF formulas has been running since 2010 based on three national R&D projects focused mainly on environmental aspects and multiaxial loading.

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Adequacy of normative documents for the actual operating conditions of sealed lead-ins for nuclear power plants

Atomic Energy ◽

10.1007/s10512-008-9048-3 ◽

2008 ◽

Vol 104 (5) ◽

pp. 410-412

Author(s):

N. S. Kostyukov ◽

V. A. Demchuk ◽

V. A. Okhotnikov

Keyword(s):

Nuclear Power ◽

Power Plants ◽

Nuclear Power Plants ◽

Operating Conditions ◽

Normative Documents ◽

Actual Operating

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Nuclear Power Plant Fires and Explosions: Part I — Plant Designs and Hydrogen Ignition

Volume 4: Fluid-Structure Interaction ◽

10.1115/pvp2017-66285 ◽

2017 ◽

Cited By ~ 1

Author(s):

Robert A. Leishear

Keyword(s):

Nuclear Power ◽

Power Plants ◽

Nuclear Power Plants ◽

Nuclear Reactor ◽

Hydrogen Generation ◽

Reactor Power ◽

Pressurized Water ◽

Hydrogen Ignition ◽

History Of ◽

Water Reactors

Requiring further investigation, hydrogen explosions and fires have occurred in several operating nuclear reactor power plants. Major accidents that were affected by hydrogen fires and explosions included Chernobyl, Three Mile Island, and Fukushima Daiichi. Smaller piping explosions have occurred at Hamaoka and Brunsbüttel Nuclear Power Plants. This paper is the first paper in a series of publications to discuss this issue. In particular, the different types of reactors that have a history of fires and explosions are discussed here, along with a discussion of hydrogen generation in commercial reactors, which provides the fuel for fires and explosions in nuclear power plants. Overall, this paper is a review of pertinent information on reactor designs that is of particular importance to this multi-part discussion of hydrogen fires and explosions. Without a review of reactor designs and hydrogen generation, the ensuing technical discussions are inadequately backgrounded. Consequently, the basic designs of pressurized water reactors (PWR’s), boiling water reactors (BWR’s), and pressure-tube graphite reactors (RBMK) are discussed in adequate detail. Of particular interest, the Three Mile Island design for a PWR is presented in some detail.

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A new approach to analysis of water chemistry indicators in the first loop of reactor installations in nuclear power plants with VVÉR reactors

Atomic Energy ◽

10.1007/bf02673577 ◽

1999 ◽

Vol 87 (3) ◽

pp. 646-652

Author(s):

V. K. Bel’nov ◽

S. I. Serdyukov ◽

S. A. Kabakchi ◽

O. P. Arkhipov ◽

V. L. Bugaenko

Keyword(s):

Water Chemistry ◽

Nuclear Power ◽

Power Plants ◽

Nuclear Power Plants ◽

New Approach

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Methodology for Establishing Segmentation Strategy for Large Metal Components from Nuclear Power Plants with Consideration of Packaging into Containers

Science and Technology of Nuclear Installations ◽

10.1155/2021/8814536 ◽

2021 ◽

Vol 2021 ◽

pp. 1-19

Author(s):

Jae Min Lee ◽

Jae Hak Cheong ◽

Jooho Whang

Keyword(s):

Case Studies ◽

3D Modeling ◽

Nuclear Power ◽

Power Plants ◽

Nuclear Power Plants ◽

Sensitivity Analyses ◽

Optimal Dimension ◽

New Approach ◽

Segmentation Strategy ◽

Ellipsoidal Shape

A methodology for segmenting large metal components from nuclear power plants has been developed with a view to minimizing the number of containers to emplace segmented pieces. Spherocylinder-type and rectangular prism-type objects are modeled in shapes, and equations to calculate heights, widths, lengths, or angles for segmentation and the number of pieces are derived using geometric theorems, with a hypothetical ‘virtual rectangle’ being introduced for simplification. Applicability of the new methodology is verified through case studies assuming that each segmented piece is packaged into a 200 L container, and a procedure for adjusting potential overestimation of the segmented pieces due to the virtual rectangle is proposed. The new approach results in fewer segmented pieces but more containers than an existing segmentation study using 3D modeling. It is demonstrated that the number of containers can be further reduced, however, if the generalized methodology is followed by 3D modeling. In addition, it is confirmed that the generalized approach is also applicable to a nonstandard shapes such as ellipsoidal shape but only under limited conditions. Sensitivity analyses are conducted by changing dimensions of the objects and container, which brings about an optimal dimension of container as well. The generalized approach would be utilized either alone in decommissioning planning to estimate waste from segmentation of large metal components or combined with 3D modeling to optimize segmentation operation.

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Paradigm shift in technical hydrobiology: from local impact, to a new techno-ecosystem concept for thermal and nuclear plant water

Ecosystem Transformation ◽

10.23859/estr-201022 ◽

2021 ◽

Vol 4 (1) ◽

pp. 3-9

Author(s):

Aleksandr A. Protasov

Keyword(s):

Climate Change ◽

Paradigm Shift ◽

Aquatic Ecosystems ◽

Nuclear Power ◽

Power Plants ◽

Nuclear Power Plants ◽

Thermal Power ◽

History Of ◽

Local Impact ◽

The Impact

Based on analysis of F.D. Mordukhai-Boltovskoy’s publications, this paper examines the history of studies of the impact of thermal and nuclear power plants, which were originally performed under the classical “Haeckelian” ecological paradigm: the external effect of technogenic factors on aquatic ecosystems and biota. The decline in interest in the problem was not associated with a decrease in the technogenic impact or changes in the energy industry. However, the paradigm itself is changing in association with the emergence of the concept of a technoecosystem. The cooling ponds of thermal power plants (TPPs) and nuclear power plants (NPPs) can be used as models of climate change, particularly climate warming. The materials obtained in studies of the effects of technogenic temperature rise are still underused by hydrobiologists studying climate change and its potential consequences.

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