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Abstract• The design and analysis, as well as the operations and maintenance (O&M) of
nuclear power plants involves the accumulation and evaluation of large heterogeneous data sets which have implications to both plant safety and financial performance. This heterogeneity is manifested in the multiplicity of physics, time scales, and general data structure. Uncertainty pervades such data sets thus rendering nondeterministic engineering analysis methods (i.e., “analytics”) of paramount importance.
• This presentation highlights two specific successful projects within which Westinghouse has successfully made value-added use of large data sets combined with analytics methods and uncertainty quantification (UQ).
– The first project involves the evaluation of flow-induced vibration (FIV) associated with the startup of a new plant design, including the Comprehensive Vibration Assessment Program (CVAP) and companion Hot Functional Testing (HFT).
– The second project involves the development of a semi-empirical prognostic reliability model to simulate baffle-former bolt degradation attributed to Irradiation Assisted Stress Corrosion Cracking (IASCC).
• While those two projects represent a small sample of recently completed projects, Westinghouse is presently moving towards making analytics-based enhancements to engineering services offerings in the areas such as Condition Based Maintenance (CBM) and Structural Health Monitoring (SHM), and Probabilistic Risk Assessment (PRA), and that vision is briefly described.
Synopsis - The Comprehensive Vibration Assessment Program (CVAP) for AP1000® Plant Reactor Internals
AP1000 is a trademark or registered trademark in the United States of Westinghouse Electric Company LLC, its subsidiaries and/or its affiliates. This mark may also be used and/or registered in other countries throughout the world. All rights reserved.
AP1000 Plant Reactor Internals – Historical Precedent• Although Reg. Guide 1.20 classifies the AP1000 Plant
Reactor Internals as prototype due to various first-of-a-kind (FOAK) design features, the majority of the AP1000 Plant Reactor Internals design is similar to existing plants that have been safely operating for many years.
Legacy Westinghouse plant experience has provided insight to AP1000 Plant CVAP
Turbulence… is not easy to define, understand, and characterize… but it dominates the flow-induced response of primary equipment within a nuclear plant!
“When I meet God, I am going to ask him two questions: Why relativity? And why turbulence? I really believe he will have an answer to the first”
AP1000 Plant Reactor Internals – Signal Processing• A test results post-processing and plotting software has been
developed that has the following capabilities:– Multi-windowing options, filtering options (high, low, pass, notch)– Coherent noise reduction (Condition Spectral Density)– Autospectra / PSDs– Cross-Spectra / Coherence / Phase– Circumferential Wavenumber Decomposition– Mode shape phase plotter– Readily available integration of acceleration to displacement as well as
narrowband frequency range definition• Process/store complete covariance matrix (~ 130 sensors for CVAP
+ co-process with other plant sensors) • DAQ/software made measurement comparisons to acceptance
criteria during testing
Quick turnaround of complex analysis informed day-to-day activities during Hot Functional
Conclusions• The Westinghouse AP1000 Plant construction and Hot
Functional Testing (HFT) were successfully completed, and the pilot plant is now operational– Compliance with regulatory guidance has been demonstrated
• Extensive analyses have been performed to establish CVAP test predictions and acceptance criteria for which the structural response is driven by various FIV excitation mechanisms, including random turbulence and acoustic phenomena
• This involved the efficient processing, storage, transmittal, and analysis of large computational and experimental data sets
Flow-Induced Vibrations constitute very large data sets and played a critical role in
Summary• The Westinghouse BFB predictive methodology is based on a
mechanistic understanding of BFB degradation and thus employs a semi-empirical paradigm
• Evaluation incorporates parameters from several sources– Finite element analysis of the baffle-former assembly– Operating experience from PWRs– Laboratory test results of IASCC
• Good comparisons have been demonstrated between model predictions and operating
• Application of model can support:– Pre-outage expectations:
Conclusions• The design and analysis, as well as the operations and maintenance,
activities with which Westinghouse supports the nuclear industry involve the accumulation and intelligent use of vast and large data sets
• Successful analysis of such data sets has resulted in successful projects such as:– AP1000 Plant Comprehensive Vibration Assessment Program (CVAP)– Baffle-Former Bolt Predictive Modeling– Reactor Coolant Pump Turning Vane Bolt Reliability Modeling*– Fuel performance prediction using post-irradiation exams and
experimental testing*• … which is leading to further technological investments targeting:
– Condition Based Maintenance (CBM) and Structural Health Monitoring (SHM)*• Both active (i.e., pumps) and passive (i.e., pipes) components