(A) study on flow accelerated corrosion behavior of nuclear power plant characterized by electrochemical method = 전기화학적 방법을 이용한 원자력발전소 배관재의 유체가속부식 (FAC) 현상 연구

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Study was focused on elucidating flow accelerated corrosion (FAC) process, which has been defined as one of the major issues in nuclear power plant, in a mechanistic point of view by rotating cylinder electrode from which it was revealed as an effective device to assess velocity sensitive testing. These include proposing electrochemical methodologies in analyzing FAC, analyzing synergistic effect on corrosion behavior of base and weld metal with turbulent flow, and evaluating FAC behavior simulating high temperature, high pressure system to give light on FAC prediction model. Activation and mass transfer process regarding the FAC of low alloy steel were studied in deaerated weak alkaline solution. Electrochemical corrosion potential (ECP) and electrochemical corrosion current density was measured with a temperature range from 25℃ to 270℃ and various rotating velocity through polarization test. At room temperature, alkaline corrosion appeared above pH 10.4, where passive film was formed from pH 9.8 by the step oxidation and subsequent precipitation of ferrous hydroxyl compound. At higher temperature, formation of magnetite on the steel surface occurred, caused ECP to drop at the rate of -1.51mV/℃. ECP shifted upward with rotating condition in all temperature range by the mechanisms of diffusion of oxidizing agent, which greatly depend on both temperature and dissolved oxygen. From the comparison between electrochemical corrosion current density and cathodic deposition current density on steel surface revealed that activation process firstly dominated at room temperature, soon mass transfer process control the entire corrosion kinetics with the increase of temperature. Chemical and geometric effects of weld on FAC of SA106 Gr.C low alloy steel pipe was investigated using rotating cylinder electrode in 3.5wt% sodium chloride solution and simulated feedwater of nuclear power plants. Polarization test and weight loss test were conducted at rotating speed of 2000rpm ...
Advisors
Kim, In-Sup김인섭
Description
한국과학기술원 : 원자력및양자공학과,
Publisher
한국과학기술원
Issue Date
2003
Identifier
181064/325007 / 000985094
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 원자력및양자공학과, 2003.2, [ ix, 133 p. ]

Keywords

Weldment corrosion; Nuclear piping; Rotating cylinder electrode; Flow accelerated corrosion; High temperature electrochemistry; 고온 전기화학; 용접재 부식; 원자력발전소 배관재; 회전 원통전극; 유체가속부식

URI
http://hdl.handle.net/10203/48945
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=181064&flag=dissertation
Appears in Collection
NE-Theses_Ph.D.(박사논문)
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