Preferential intergranular oxidation as a potential degradation mechanism for Alloy X-750 CANDU spacers

A.e. Yaedu; L. Volpe; J.d. Henderson; S. Ramamurthy; K. Daub; F. Scenini; S.y. Persaud

doi:10.1016/j.jnucmat.2024.155007

Preferential intergranular oxidation as a potential degradation mechanism for Alloy X-750 CANDU spacers

A.e. Yaedu, L. Volpe, J.d. Henderson, S. Ramamurthy, K. Daub, F. Scenini, S.y. Persaud

Materials Engineering

Research output: Contribution to journal › Article › peer-review

Abstract

Oxidation experiments on Alloy X-750 were performed in reducing CO-CO₂ mixtures to assess the possibility of preferential intergranular oxidation (PIO) in relation to CANDU garter-spring spacers. The testing environments simulate hypothetical off-chemistry scenarios, promoting the oxidation of the alloying elements, but not Ni. Surface and cross-section microscopy corroborated by Auger electron spectroscopy confirmed the occurrence of internal and intergranular oxidation in Alloy X-750, accompanied by Ni nodule expulsion to the surface. Results are qualitatively similar to observations in Alloy 600 exposed to 480°C hydrogenated steam, used as an accelerated environment for primary water stress corrosion cracking (PWSCC) testing.

Original language	English
Article number	155007
Journal	Journal of Nuclear Materials
Early online date	8 Mar 2024
DOIs	https://doi.org/10.1016/j.jnucmat.2024.155007
Publication status	E-pub ahead of print - 8 Mar 2024

Keywords

CANDU spacer
Alloy X-750
preferential intergranular oxidation

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10.1016/j.jnucmat.2024.155007Licence: CC BY

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title = "Preferential intergranular oxidation as a potential degradation mechanism for Alloy X-750 CANDU spacers",

abstract = "Oxidation experiments on Alloy X-750 were performed in reducing CO-CO2 mixtures to assess the possibility of preferential intergranular oxidation (PIO) in relation to CANDU garter-spring spacers. The testing environments simulate hypothetical off-chemistry scenarios, promoting the oxidation of the alloying elements, but not Ni. Surface and cross-section microscopy corroborated by Auger electron spectroscopy confirmed the occurrence of internal and intergranular oxidation in Alloy X-750, accompanied by Ni nodule expulsion to the surface. Results are qualitatively similar to observations in Alloy 600 exposed to 480°C hydrogenated steam, used as an accelerated environment for primary water stress corrosion cracking (PWSCC) testing.",

keywords = "CANDU spacer, Alloy X-750, preferential intergranular oxidation",

author = "A.e. Yaedu and L. Volpe and J.d. Henderson and S. Ramamurthy and K. Daub and F. Scenini and S.y. Persaud",

year = "2024",

month = mar,

day = "8",

doi = "10.1016/j.jnucmat.2024.155007",

language = "English",

journal = "Journal of Nuclear Materials",

issn = "0022-3115",

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TY - JOUR

T1 - Preferential intergranular oxidation as a potential degradation mechanism for Alloy X-750 CANDU spacers

AU - Yaedu, A.e.

AU - Volpe, L.

AU - Henderson, J.d.

AU - Ramamurthy, S.

AU - Daub, K.

AU - Scenini, F.

AU - Persaud, S.y.

PY - 2024/3/8

Y1 - 2024/3/8

N2 - Oxidation experiments on Alloy X-750 were performed in reducing CO-CO2 mixtures to assess the possibility of preferential intergranular oxidation (PIO) in relation to CANDU garter-spring spacers. The testing environments simulate hypothetical off-chemistry scenarios, promoting the oxidation of the alloying elements, but not Ni. Surface and cross-section microscopy corroborated by Auger electron spectroscopy confirmed the occurrence of internal and intergranular oxidation in Alloy X-750, accompanied by Ni nodule expulsion to the surface. Results are qualitatively similar to observations in Alloy 600 exposed to 480°C hydrogenated steam, used as an accelerated environment for primary water stress corrosion cracking (PWSCC) testing.

AB - Oxidation experiments on Alloy X-750 were performed in reducing CO-CO2 mixtures to assess the possibility of preferential intergranular oxidation (PIO) in relation to CANDU garter-spring spacers. The testing environments simulate hypothetical off-chemistry scenarios, promoting the oxidation of the alloying elements, but not Ni. Surface and cross-section microscopy corroborated by Auger electron spectroscopy confirmed the occurrence of internal and intergranular oxidation in Alloy X-750, accompanied by Ni nodule expulsion to the surface. Results are qualitatively similar to observations in Alloy 600 exposed to 480°C hydrogenated steam, used as an accelerated environment for primary water stress corrosion cracking (PWSCC) testing.

KW - CANDU spacer

KW - Alloy X-750

KW - preferential intergranular oxidation

U2 - 10.1016/j.jnucmat.2024.155007

DO - 10.1016/j.jnucmat.2024.155007

M3 - Article

SN - 0022-3115

JO - Journal of Nuclear Materials

JF - Journal of Nuclear Materials

M1 - 155007

ER -

Preferential intergranular oxidation as a potential degradation mechanism for Alloy X-750 CANDU spacers

Abstract

Keywords

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