A Thin Alumina Film as a Tritium Adsorption Inhibitor for Stainless Steel 316

Abstract

The effect of a thin alumina coating on stainless steel 316 (SS316) samples on tritium adsorption and transport are reported. Compact films of alumina were produced on the surfaces of pristine SS316 samples using an atomic layer deposition (ALD) technique. Subsequently, these samples were exposed for 24 h to a deuterium-tritium gas mixture (P_T = 0.5 atm, 25°C). A combination of methods including selective etching and programmed thermal desorption were employed to assess both the depth profile of the tritium concentration in the sample and the total quantity of tritium absorbed, respectively. Tritium was quantitatively determined through the measurement of beta radioactivity using liquid-scintillation counting techniques. Data suggest that SS316 with a thin film of alumina reduces the total tritium uptake by ~25% relative to uncoated samples. Importantly, such films appear to reduce, by a factor of 200, tritium diffusion into SS316 and therefore constitute an effective barrier against tritium transport. This observation is of practical importance for tritium and, generally, reactive gas handling.

Keywords:

• Tritium materials
• atomic layer deposition
• thin alumina film

Acknowledgments

The authors acknowledge Mike Koch, Sal Scarantino, and Ben Ruth (University of Rochester’s Laboratory of Laser Energetics Cryogenic Tritium Facility) for their work exposing the test samples to tritium gas. The authors also acknowledge Chris Pratt and Professor Stephen Burns for the X-ray reflectivity analysis, and Brian McIntyre and Ralph Wiegandt of the University of Rochester’s Nanosystem Center for the TEM sample preparation. This material is based on work supported by the U.S. Department of Energy (DOE) National Nuclear Security Administration under award number DE-NA0003856 and the University of Rochester and the New York State Energy Research and Development Authority. The support of DOE does not constitute an endorsement by DOE of the views expressed in this paper.

This paper was prepared as an account of work sponsored by an agency of the U.S. government. Neither the U.S. government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the U.S. government or any agency thereof. The views and opinions of the authors expressed herein do not necessarily state or reflect those of the U.S. government or any agency thereof.