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Title: Neutralization of steam generator denting. Volume 2. Final report. [PWR]

Abstract

This report deals with experimental laboratory work, the purpose of which was to reproduce the denting phenomenon observed in some steam generator heat transfer tubing and then to determine the effectiveness of selected candidate additives with regard to their ability to inhibit the denting phenomenon. Denting was shown to be dependent on a synergism between materials, oxidants, chloride, crevice geometry, superheats and temperature. A reference denting environment was developed and candidate inhibitors to this environment were subsequently added in an attempt to prevent and/or stop the denting process. Boric acid applications in a soak/on-line mode were found to be completely effective with no indications of deleterious side effects. Boric acid has been recommended for field application on a plant-specific basis. Calcium hydroxide and sodium phosphate additions in an on-line mode were effective inhibitors.

Authors:
; ; ;
Publication Date:
Research Org.:
Westinghouse Electric Corp., Pittsburgh, PA (USA). Nuclear Technology Div.
OSTI Identifier:
5350251
Alternate Identifier(s):
OSTI ID: 5350251; Legacy ID: DE84920040
Report Number(s):
EPRI-NP-3023-Vol.2
ON: DE84920040
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; 36 MATERIALS SCIENCE; INCONEL 600; CORROSION DENTING; PWR TYPE REACTORS; STEAM GENERATORS; REACTOR MATERIALS; TUBES; BORIC ACID; CALCIUM HYDROXIDES; CORROSION INHIBITORS; PERFORMANCE TESTING; WATER CHEMISTRY; ALKALINE EARTH METAL COMPOUNDS; ALLOYS; BOILERS; CALCIUM COMPOUNDS; CHEMISTRY; CHROMIUM ALLOYS; DEFORMATION; HYDROGEN COMPOUNDS; HYDROXIDES; INCONEL ALLOYS; INORGANIC ACIDS; IRON ALLOYS; MATERIALS; NICKEL ALLOYS; NICKEL BASE ALLOYS; NIOBIUM ALLOYS; OXYGEN COMPOUNDS; REACTORS; TESTING; VAPOR GENERATORS; WATER COOLED REACTORS; WATER MODERATED REACTORS 210200* -- Power Reactors, Nonbreeding, Light-Water Moderated, Nonboiling Water Cooled; 360105 -- Metals & Alloys-- Corrosion & Erosion

Citation Formats

Wolfe, C.R., Esposito, J.N., Wozniak, S.M., and Whyte, D.D.. Neutralization of steam generator denting. Volume 2. Final report. [PWR]. United States: N. p., 1983. Web.
Wolfe, C.R., Esposito, J.N., Wozniak, S.M., & Whyte, D.D.. Neutralization of steam generator denting. Volume 2. Final report. [PWR]. United States.
Wolfe, C.R., Esposito, J.N., Wozniak, S.M., and Whyte, D.D.. Thu . "Neutralization of steam generator denting. Volume 2. Final report. [PWR]". United States. doi:.
@article{osti_5350251,
title = {Neutralization of steam generator denting. Volume 2. Final report. [PWR]},
author = {Wolfe, C.R. and Esposito, J.N. and Wozniak, S.M. and Whyte, D.D.},
abstractNote = {This report deals with experimental laboratory work, the purpose of which was to reproduce the denting phenomenon observed in some steam generator heat transfer tubing and then to determine the effectiveness of selected candidate additives with regard to their ability to inhibit the denting phenomenon. Denting was shown to be dependent on a synergism between materials, oxidants, chloride, crevice geometry, superheats and temperature. A reference denting environment was developed and candidate inhibitors to this environment were subsequently added in an attempt to prevent and/or stop the denting process. Boric acid applications in a soak/on-line mode were found to be completely effective with no indications of deleterious side effects. Boric acid has been recommended for field application on a plant-specific basis. Calcium hydroxide and sodium phosphate additions in an on-line mode were effective inhibitors.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Sep 01 00:00:00 EDT 1983},
month = {Thu Sep 01 00:00:00 EDT 1983}
}

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  • This report deals with experimental laboratory work, the purpose of which was to reproduce the denting phenomenon observed in some steam generator heat transfer tubing and then to determine the effectiveness of selected candidate additives with regard to their ability to inhibit the denting phenomenon. Denting was shown to be dependent on a synergism between materials, oxidants, chloride, crevice geometry, superheats and temperature. A reference denting environment was developed and candidate inhibitors to this environment were subsequently added in an attempt to prevent and/or stop the denting process. Boric acid applications in a soak/on-line mode were found to be completelymore » effective with no indications of deleterious side effects. Boric acid has been recommended for field application on a plant-specific basis. Calcium hydroxide and sodium phosphate additions in an on-line mode were effective inhibitors.« less
  • This report presents the results of a structural analysis of steam generator tubes, tube support plates and tubesheet when tube denting has caused tubes to lock into support plates. A section of a support plate with associated tubes was modeled by finite element techniques to determine the maximum axial load in the tubes imposed by differential thermal expansion. The tube structural integrity was addressed from the standpoint of flow induced vibrations and fatigue for the imposed axial loading. The maximum stress in the perforated plate due to locked tubes was determined by finite element methods. The axial loads in themore » tubes were applied to a tubesheet finite element model to determine the primary bending stresses. Axial loads in the tubes were applied as a concentrated load through the tubesheet thickness to determine maximum shear. The stresses from these analyses were compared to the ASME Code Section III allowables and were found to be acceptable.« less
  • This report summarizes ADA work done under EPRI contract TPS81-777, PWR Steam Generator Cost-Benefit Model Development. This project demonstrates how cost-benefit analysis can be applied to the various maintenance, repair, and design options for improving the reliability and economic life of pressurized water reactor (PWR) steam generators. A preliminary model applies this methodology to steam generator denting damage. Analysis of a realistic example using this model confirms that a cost-benefit methodology is valuable for comparing the effectiveness of alternative corrective action options. Future steps include EPRI use of the preliminary model, model refinement, model expansion and extension to other damagemore » mechanisms, and preparation of the model for use by utility decision makers.« less
  • Corrosion results obtained from the post-test non-destructive and destructive examinations of an alternative materials model steam generator are described in this final report. The model operated under representative thermal and hydraulic and accelerated (high seawater contaminant concentration) steam generator secondary water chemistry conditions. Total exposure consisted of 114 steaming days under all volatile treatment (AVT) chemistry conditions followed by 282 fault steaming days at a 30 ppM chloride concentration in the secondary bulk water. Various support plate and lattice strip support designs incorporated Types 347, 405, 409 and SCR-3 stainless steels; Alloys 600 and 690; and carbon steel. Heat transfermore » tube materials included Alloy 600 in various heat treated conditions, Alloy 690, and Alloy 800. All tubing materials in this test exhibited moderate pitting, primarily in the sludge pile region above the tubesheet.« less
  • A test program was conducted to determine for selected steam generator tube supports the thermal/hydraulic conditions at the inception of dryout as indicated by a tube wall temperature excursion, to determine the pressure drop across the supports, and to obtain photographic documentation of the flow upstream and downstream of the supports. A multi-tube steam generator model was used and testing performed over the range of typcal PWR steam generator operating conditions. These appendices contain information on instrumentation calibration, test model and loop calibration, error analysis, test model thermal-hydraulic analyses, index of lab materials and log sheets, index of two-phase flowmore » still photographs, index of high speed movies and video, test data printouts, test model and loop fabrication drawings, procedure for silver brazing tubewall thermocouples, and procedure for esablishing tube-tube support line contact.« less