RESULTS ON INCOLOY 800 AND ALLIED STEAM GENERATOR MATERIALS IN FLORIDA FIELD CORROSION TESTS*

The first CANDU (CANadian Deuterium Uranium) pressurized heavy water reactor (PHWR) went into operation in July 1971. Today, there are several units in operation at the Pickering, Bruce, and Darlington sites in Ontario, Canada. The steam generator tubing materials were manufactured from Monel 400, Inconel 600, and Incoloy 800 for the Pickering, Bruce, and Darlington respectively and are subjected to different operating conditions. This paper presents a review of some of the various types of degradation mechanisms that have been observed on these tubing materials over the operating period of the respective plants. The results presented are based on the metallurgical examination of removed tubes. The mechanisms that have been observed include pitting, stress corrosion cracking, intergranular attack, fretting, and erosion corrosion. The nature of the flaws and causative factors (if known) are discussed.

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Characterization of damage and triboparticles resulting from fretting of Incoloy 800 steam generator tubes against different materials

Wear ◽

10.1016/j.wear.2017.07.022 ◽

2017 ◽

Vol 390-391 ◽

pp. 198-208 ◽

Cited By ~ 13

Author(s):

S.R. Soria ◽

A. Tolley ◽

A. Yawny

Keyword(s):

Steam Generator ◽

Incoloy 800 ◽

Steam Generator Tubes

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Characterization and Structural Integrity Tests of Ex-Service Steam Generator Tubes

Volume 1: Plant Operations, Maintenance, Installations and Life Cycle; Component Reliability and Materials Issues; Advanced Applications of Nuclear Technology; Codes, Standards, Licensing and Regulatory Issues ◽

10.1115/icone16-48505 ◽

2008 ◽

Author(s):

Sandra Pagan ◽

Xinjian Duan ◽

Michael J. Kozluk ◽

Brian Mills ◽

Guylaine Goszczynski

Keyword(s):

Mechanical Properties ◽

Power Generation ◽

Steam Generator ◽

Structural Integrity ◽

Incoloy 800 ◽

Full Power ◽

Monel 400 ◽

Integrity Tests ◽

Steam Generator Tubes

Canadian nuclear standard CSA N285.4 requires the periodic metallurgical examination of removed ex-service steam generator tubes. This paper describes the practices used for the characterization and structural integrity tests of ex-service steam generator tubes at Ontario Power Generation (OPG). It shows that there is no degradation in mechanical properties of Monel 400 tubes after 7 to 18 Effective Full Power Years (EFPY) of operation and Incoloy 800 tubes after more than 10 EFPY of operation.

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Electro chemical studies on stress corrosion cracking of Incoloy-800 in caustic solution, part I: As received samples

Nuclear Technology and Radiation Protection ◽

10.2298/ntrp0501074d ◽

2005 ◽

Vol 20 (1) ◽

pp. 74-80 ◽

Cited By ~ 2

Author(s):

Alice Dinu ◽

Manuela Fulger ◽

Dragos Ionescu ◽

Lucian Velciu ◽

Maria Radulescu

Keyword(s):

Stress Corrosion ◽

Steam Generator ◽

Stress Corrosion Cracking ◽

Corrosion Current ◽

Corrosion Cracking ◽

Caustic Solution ◽

Potentiodynamic Curves ◽

Naoh Solution ◽

Incoloy 800 ◽

Chemical Studies

Many non-volatile impurities accidentally introduced into the steam generator tend to Concentrate on its surface in restricted flow areas. In this way these impurities can lead to stress corrosion cracking (SCC) on stressed tubes of the steam generator. Such impurities can be strong alkaline or acid solutions. To evaluate the effect of alkaline concentrated environments on SCC of steam generator tubes, the tests were con ducted on stressed samples of Incoloy-800 in 10% NaOH solution. To accelerate the SCC process, stressed specimens were anodically polarised in a caustic solution in an electro chemical cell. The method of stressing of Incoloy-800 tubes used in our experiments was the C-ring. Using the cathodic zone of the potentiodynamic curves it was possible to calculate the most important electrochemical parameters: the corrosion current, the corrosion rate, and the polarization resistance. We found that the value of the corrosion potential to initiate the SCC microcracks was -100 mV. The tested samples were examined using the metallographic method. The main experimental results showed that the in crease of the stress state promoted the in crease of the SCC susceptibility of Incoloy-800 samples tested under the same conditions, and that the length of the SCC-type microcracks in creased with the growth of the stress value.

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