ICONE19-43257 TUBE SUPPORT PLATE BLOCKAGE IN STEAM GENERATORS : INVERSE METHOD FOR THE ESTIMATION OF UNOBSERVABLE PARAMETERS IN A DEPOSIT MODEL

Experimental results are presented on the influence of confinement (normal to heated surface) on nucleate boiling in forced flow. The forced flow conditions and confinement geometry studied are similar to those found for boiling between a primary-fluid tube and a tube-support plate in steam generators of pressurized-water-reactor nuclear power plants. Visual observations of the boiling process within the confined region (crevice) between the tube and its support plate, obtained by high-speed photography, are related to simultaneous two-dimensional temperature maps of the hot primary-fluid-tube surface. The results demonstrate the existence of three confinement-dependent boiling regimes in forced flow conditions that are similar to those found in pool boiling conditions. These regimes are shown to be associated with the Weber number.

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Review of tube support plate analysis for steam generators of Millstone Unit II Nuclear Power Plant

10.2172/6272943 ◽

1978 ◽

Author(s):

S.M. Ma ◽

S.C.H. Lu

Keyword(s):

Power Plant ◽

Nuclear Power Plant ◽

Nuclear Power ◽

Steam Generators ◽

Support Plate ◽

Plate Analysis

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Impact of preventive and curative remedies for steam generators fouling and tube support plate blockage on secondary circuit materials

Revue Générale Nucléaire ◽

10.1051/rgn/20111087 ◽

2011 ◽

pp. 87-97

Author(s):

M. Alves Vieira ◽

M. Dijoux ◽

O. de Bouvier ◽

M. Mayos ◽

N. Coquio

Keyword(s):

Secondary Circuit ◽

Steam Generators ◽

Support Plate

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A Theory for Fluidelastic Instability of Tube-Support-Plate-Inactive Modes

Journal of Pressure Vessel Technology ◽

10.1115/1.2929021 ◽

1992 ◽

Vol 114 (2) ◽

pp. 139-148 ◽

Cited By ~ 2

Author(s):

Y. Cai ◽

S. S. Chen ◽

S. Chandra

Keyword(s):

Heat Exchangers ◽

Linear Models ◽

Cross Flow ◽

Bilinear Model ◽

Steam Generators ◽

Unstable Region ◽

Fluid Forces ◽

Support Plate ◽

Fluidelastic Instability ◽

Inactive Mode

Fluidelastic instability of loosely supported tubes, vibrating in a tube support plate (TSP)-inactive mode, is suspected to be one of the main causes of tube failure in some operating steam generators and heat exchangers. This paper presents a mathematical model for fluidelastic instability of loosely supported tubes exposed to nonuniform cross flow. The model incorporates all motion-dependent fluid forces based on the unsteady-flow theory. In the unstable region associated with a TSP-inactive mode, tube motion can be described by two linear models: TSP-inactive mode when tubes do not strike the TSP, and TSP-active mode when tubes do strike the TSP. The bilinear model (consisting of these linear models) presented here simulates the characteristics of fluidelastic instability of loosely supported tubes in stable and unstable regions associated with TSP-inactive modes. Analytical results obtained with the model are compared with published experimental data; they agree reasonably well. The prediction procedure presented for the fluidelastic instability response of loosely supported tubes is applicable to the stable and unstable regions of the TSP-inactive mode.

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Flow-Induced Wear in Steam Generator Tubes—Prediction Versus Operational Experience

Journal of Pressure Vessel Technology ◽

10.1115/1.2842231 ◽

1998 ◽

Vol 120 (2) ◽

pp. 138-143 ◽

Cited By ~ 9

Author(s):

M. K. Au-Yang

Keyword(s):

Steam Generator ◽

Tube Wall ◽

Tube Bundle ◽

Cross Flow ◽

Operational Experience ◽

Steam Generators ◽

Support Plate ◽

Power Operations ◽

Full Power ◽

Steam Generator Tubes

Many nuclear steam generators have accumulated more than 10 effective-full-power-years of operation. Eddy-current inspections revealed that a number of these steam generator tubes, notably those located in high local cross-flow regions, have indications of wear at some support plate elevations after 5 to 10 yr of effective-full-power operations. In the last 5 yr, a number of technical papers on nonlinear tube bundle dynamics has been published to address the effect of tube and support plate interactions. At the same time, test data relating wear and tube wall thickness losses for different material combinations and different support plate geometries became available. Based on the available data in the literature, as well as data obtained in the author’s affiliation, this paper assesses the cumulative tube wall wear after 5, 10, and 15 effective-full-power years of operation of a typical commercial nuclear steam generator, using different wear models. It is hoped that this study will shed some light on the probable mechanism that caused the observed wear in today’s operating nuclear steam generators.

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Dynamic Characteristics of Heat Exchanger Tubes Vibrating in a Tube Support Plate Inactive Mode

Journal of Pressure Vessel Technology ◽

10.1115/1.3264784 ◽

1986 ◽

Vol 108 (3) ◽

pp. 256-266 ◽

Cited By ~ 6

Author(s):

J. A. Jendrzejczyk

Keyword(s):

Experimental Study ◽

Heat Exchanger ◽

Heat Exchangers ◽

Damping Ratio ◽

Steam Generators ◽

Support Plate ◽

Interaction Dynamics ◽

Fabrication Tolerances ◽

Shell And Tube ◽

Inactive Mode

Tubes in shell-and-tube heat exchangers, including nuclear plant steam generators, derive their support from longitudinally positioned tube support plates (TSPs). Typically, there is a clearance between the tube and TSP hole. Depending on design and fabrication tolerances, the tube may or may not contact all of the TSPs. Non-contact results in an inactive TSP which can lead to detrimental flow-induced tube vibrations under certain conditions dependent on the resulting tube-TSP interaction dynamics and the fluid excitation forces. The purpose of this study is to investigate the tube-TSP interaction dynamics. Results of an experimental study of damping and natural frequency as functions of tube-TSP diametral clearance and TSP thickness are reported. Calculated values of damping ratio and frequency of a tube vibrating within an inactive TSP are also presented together with a comparison of calculated and experimental quantities.

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Block Monitoring Method of SG Tube Support Plate With Intelligent ECT for Maintenance Work

Volume 1B: Codes and Standards ◽

10.1115/pvp2015-45924 ◽

2015 ◽

Author(s):

Masaki Noda ◽

Yuki Kobayashi

Keyword(s):

New Method ◽

Steam Generators ◽

Monitoring Method ◽

Support Plate ◽

Maintenance Work ◽

Analysis System ◽

Data Analysis System ◽

Secondary Side ◽

Water Level Oscillation ◽

Scale Deposits

Intelligent ECT (Eddy Current Testing) probe (I-Probe) has a capability to inspect tubes more productively and more accurately than conventional probes for Steam Generators (SG) as shown in Fig. 1. And I-Probe provides effective “One-Pass” solution by combination with MHI (Mitsubishi Heavy Industries, Ltd.) Intelligent Data Analysis System (MIDAS) [1]. It has been applied to full length tube inspection in Japan since 2003 and there is much field experience to date. On the other hand, a phenomenon in SG secondary side is known that scale deposits clog holes of quatrefoil type tube support plate (TSP). Water level oscillation of secondary side caused by excessive blockage of scale deposits may decrease operation efficiency and it can be a cause of unintended troubles. Therefore, periodical monitoring of blockage condition and applying countermeasures like secondary side cleaning are very important. A new method has been developed to evaluate blockage condition of every TSP around all tubes automatically using I-Probe data. Also, a new software has been developed to visualize the evaluation results as color maps. This new method may contribute to increase the reliability of SG maintenance like cleaning, because the new method makes it possible to monitor a whole SG condition more precisely.

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