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Updated: May 11, 2026
14:11
Quantification of Hydrogen Concentrations in Surface and Interface Layers and Bulk Materials through Depth Profiling with Nuclear Reaction Analysis
Published on: March 29, 2016
Hydrogen trapping in δ-Pu: insights from electronic structure calculations
Christopher D Taylor1, Sarah C Hernandez, Michael F Francis
1Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA. cdtaylor@lanl.gov
Summary
Hydrogen forms an anionic hydride in plutonium (Pu) with exothermic binding energies across all states. This explains the low activation energy observed in plutonium hydriding reactions.
Area of Science:
- Materials Science
- Computational Chemistry
- Solid-State Physics
Background:
- Plutonium (Pu) alloys are critical in nuclear applications.
- Understanding hydrogen's interaction with plutonium is vital for safety and material stability.
- The Flanagan model describes hydrogen-metal interactions through various states.
Purpose of the Study:
- To investigate the structural and charge-transfer properties of hydrogen in solid solution within delta-plutonium (δ-Pu).
- To model the hydrogen interaction pathway in δ-Pu using the Flanagan model.
- To elucidate the energetics and electronic states of hydrogen in δ-Pu.
Main Methods:
- Density functional theory (DFT) calculations were employed.
- The special quasirandom structure (SQS) approach was used to model magnetic moment dispersion in δ-Pu.
- Calculations followed the principles of the Flanagan model for hydrogen-metal interactions.
Main Results:
- Hydrogen exhibits exothermic binding energy in all modeled states (surface, interstitial, defect-bound, hydride).
- Hydrogen is found to be anionic in all these states, with maximum charge transfer in the hydride phase.
- The pathway from surface to hydride is sequentially exothermic, indicating no energy barriers.
Conclusions:
- The DFT calculations support experimental observations of facile plutonium hydriding.
- Hydrogen readily forms an anionic hydride in δ-Pu, driven by exothermic interactions.
- The findings provide a microscopic understanding of the low activation energy for plutonium hydriding.
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