Intergranular fracture in irradiated Inconel X-750 containing very high concentrations of helium and hydrogen

Journal Article · Sun Feb 01 00:00:00 EST 2015 · Journal of Nuclear Materials

DOI:https://doi.org/10.1016/j.jnucmat.2014.10.008· OSTI ID:1177655

Judge, Colin D. ^[1]; Gauquelin, Nicolas ^[2]; Walters, Lori ^[1]; Wright, Mike ^[1]; Cole, James I. ^[3]; Madden, James ^[3]; Botton, Gianluigi A. ^[2]; Griffiths, Malcolm ^[1]

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1. Atomic Energy of Canada, Limited, Chalk River, ON (Canada)
2. McMaster Univ., Hamilton, ON (Canada)
3. Idaho National Lab. (INL), Idaho Falls, ID (United States)

In recent years, it has been determined that Inconel X-750 CANDU spacers have lost strength and material ductility following irradiation in reactor. The irradiated fracture behaviour of ex-service material was also found to be entirely intergranular. The heavily thermalized flux spectrum in a CANDU reactor results in transmutation of ⁵⁸Ni to ⁵⁹Ni. The ⁵⁹Ni itself has unusually high thermal neutron reaction cross-sections of the type: (n, γ), (n, p), and (n,α). The latter two reactions, in particular, contribute to a significant enhancement of the atomic displacements in addition to creating high concentrations of hydrogen and helium within the material. Metallographic examinations by transmission electron microscopy (TEM) have confirmed the presence of helium bubbles in the matrix and aligned along grain boundaries and matrix-precipitate interfaces. He bubble size and density are found to be highly dependent on the irradiation temperature and material microstructure; the bubbles are larger within grain boundary precipitates. TEM specimens extracted from fracture surfaces and crack tips give direct evidence linking crack propagation with grain boundary He bubbles.

• Research Organization: Idaho National Lab. (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC07-05ID14517
• OSTI ID: 1177655
• Journal Information: Journal of Nuclear Materials, Vol. 457, Issue C; ISSN 0022-3115
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 Materials Science
Inconel Alloys
SPACERS
CANDU TYPE REACTORS
IRRADIATION
THERMAL NEUTRONS
Neutron Flux
Fracture Properties
DUCTILITY
GRAIN BOUNDARIES
Neutron Reactions
CROSS SECTIONS
TRANSMUTATION
NICKEL 58
NICKEL 59
Gamma Decay
Alpha Decay
HELIUM
Helium Embrittlement
HYDROGEN
Hydrogen Embrittlement
CONCENTRATION RATIO
TRANSMISSION ELECTRON MICROSCOPY
METALLOGRAPHY
Energy-Loss Spectroscopy
BUBBLES
PRECIPITATION
Interfaces
FRACTURES
CRACK PROPAGATION
CRACKS
CANDU
EELS
EMBRITTLEMENT
INCOMEL X-750