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Title: The argument for low hydrogen and lithium operation in PWR primary circuits

Abstract

The use of high hydrogen levels in the primary circuit of a pressurized water reactor (PWR) is believed to be a possible cause of cracking of Alloy 600 steam generator tubes and other components fabricated from a variety of stainless steels and nickel-base alloys. Cracking occurs due to the electrochemical potential (ECP) being in the region for hydrogen-induced cracking, or in a region for stress corrosion cracking. In order to estimate the corrosion potential of these alloys in PWR primary environments, a series of algorithms has been developed. These algorithms have been used to determine the pH of aqueous LiOH + B(OH){sub 3} solutions, to calculate the concentration of radiolysis products produced in the core due to the neutron and {gamma}-photon fluxes, and to estimate the ECP under simulated operating conditions. From these calculations, the ECP for various hydrogen concentrations, lithium to boron ratios (as specified by a given pH), and dose rates were evaluated. The authors show that under the prescribed operating conditions for PWRs ([H{sub 2}] = 25--50 cc/kg), the corrosion potential is more negative than the critical potential ({minus}0.8 V{sub SHE}) for the onset of hydrogen induced intergranular cracking in Alloy 600. However, by lowering the hydrogenmore » concentration to less than 4 cc/kg at a pH of 7.5 and to less than 10 cc/kg at a pH of 7.0, the authors predict that it would be possible to protect Alloy 600 from fracture.« less

Authors:
; ;  [1]
  1. Pennsylvania State Univ., University Park, PA (United States). Center for Advanced Materials
Publication Date:
OSTI Identifier:
203747
Report Number(s):
CONF-950816-
ISBN 1-877914-95-9; TRN: 96:009713
Resource Type:
Book
Resource Relation:
Conference: 7. international symposium on environmental degradation of materials in nuclear power plants: water reactors, Breckenridge, CO (United States), 6-10 Aug 1995; Other Information: PBD: 1995; Related Information: Is Part Of Seventh international symposium on environmental degradation of materials in nuclear power systems -- Water reactors: Proceedings and symposium discussions. Volume 2; Airey, G.; Andresen, P.; Brown, J. [eds.] [and others]; PB: 620 p.
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 21 NUCLEAR POWER REACTORS AND ASSOCIATED PLANTS; PWR TYPE REACTORS; STEAM GENERATORS; PRIMARY COOLANT CIRCUITS; TUBES; STRESS CORROSION; CRACK PROPAGATION; INCONEL 600; WATER CHEMISTRY; STAINLESS STEEL-304; PH VALUE; LITHIUM HYDROXIDES; BORON HYDROXIDES; RADIOLYSIS; MATHEMATICAL MODELS; THEORETICAL DATA

Citation Formats

Bertuch, A, Pang, J, and Macdonald, D D. The argument for low hydrogen and lithium operation in PWR primary circuits. United States: N. p., 1995. Web.
Bertuch, A, Pang, J, & Macdonald, D D. The argument for low hydrogen and lithium operation in PWR primary circuits. United States.
Bertuch, A, Pang, J, and Macdonald, D D. Sun . "The argument for low hydrogen and lithium operation in PWR primary circuits". United States.
@article{osti_203747,
title = {The argument for low hydrogen and lithium operation in PWR primary circuits},
author = {Bertuch, A and Pang, J and Macdonald, D D},
abstractNote = {The use of high hydrogen levels in the primary circuit of a pressurized water reactor (PWR) is believed to be a possible cause of cracking of Alloy 600 steam generator tubes and other components fabricated from a variety of stainless steels and nickel-base alloys. Cracking occurs due to the electrochemical potential (ECP) being in the region for hydrogen-induced cracking, or in a region for stress corrosion cracking. In order to estimate the corrosion potential of these alloys in PWR primary environments, a series of algorithms has been developed. These algorithms have been used to determine the pH of aqueous LiOH + B(OH){sub 3} solutions, to calculate the concentration of radiolysis products produced in the core due to the neutron and {gamma}-photon fluxes, and to estimate the ECP under simulated operating conditions. From these calculations, the ECP for various hydrogen concentrations, lithium to boron ratios (as specified by a given pH), and dose rates were evaluated. The authors show that under the prescribed operating conditions for PWRs ([H{sub 2}] = 25--50 cc/kg), the corrosion potential is more negative than the critical potential ({minus}0.8 V{sub SHE}) for the onset of hydrogen induced intergranular cracking in Alloy 600. However, by lowering the hydrogen concentration to less than 4 cc/kg at a pH of 7.5 and to less than 10 cc/kg at a pH of 7.0, the authors predict that it would be possible to protect Alloy 600 from fracture.},
doi = {},
url = {https://www.osti.gov/biblio/203747}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1995},
month = {12}
}

Book:
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