Hydrogen and deuterium permeation in Hastelloy N

Journal Article · 01 December 2023 · Journal of Nuclear Materials

DOI: https://doi.org/10.1016/j.jnucmat.2023.154851 · OSTI ID:2341250

Fuerst, Thomas F.  ^[1]; Shimada, Masashi  ^[1]; Gietl, Hanns Anton  ^[1]; Humrickhouse, Paul W. ^[2]

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1. Idaho National Laboratory (INL), Idaho Falls, ID (United States)
2. Idaho National Laboratory (INL), Idaho Falls, ID (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Hastelloy N was chosen as the fluoride salt-contacting structural material for the Molten Salt Reactor Experiment due to its excellent compatibility with the fuel salt FLiBe. FLiBe is currently investigated for several advanced fusion and fission reactor concepts where tritium generation in the FLiBe is anticipated. Knowledge of hydrogen transport properties through Hastelloy N is important to understand how tritium would permeate through this material and result in an unintentional release. In this study, the hydrogen and deuterium permeability, diffusivity, and solubility were measured from 500 to 700 °C at a primary-side pressure of 10 kPa in a well-characterized sample of Hastelloy N. The prepared polycrystalline Hastelloy N had C and O impurities present on the surface. These impurities were investigated using Auger Emission Spectroscopy and Ar depth profiling. Here, the adventitious C was removed upon the first Ar sputter cycle whereas O persisted deeper into the sample. For permeation experiments, applied deuterium pressures ranged from 13 Pa to 100 kPa and deuterium transport remained in the diffusion-limited regime (J ∝ P^0.5) throughout the pressure range examined. Two methods are employed to measure the effective hydrogen and deuterium diffusivity: rise and decline. The decline method produced improved statistical model fits for calculating the effective diffusion coefficient compared to the rise method. The resultant transport properties compared well to published values for other nickel alloys.

• Research Organization: Idaho National Laboratory (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE), Reactor Fleet and Advanced Reactor Development
• Grant/Contract Number: AC07-05ID14517
• OSTI ID: 2341250
• Alternate ID(s): OSTI ID: 2369199
• Report Number(s): INL/JOU-22-65691-Revision-0; TRN: US2410569
• Journal Information: Journal of Nuclear Materials, Vol. 589; ISSN 0022-3115
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English