Correlating nanoporosity, Nb oxidation states and deuterium transport in the oxide layer formed on a Zr-2.5 Nb alloy
Bibliographic record
Abstract
In Canada Deuterium Uranium reactors, Zr-2.5 Nb alloys are used as a pressure boundary material and understanding corrosion and deuterium transport is critical. The objective of this study is to characterize the oxide layer formed on Zr-2.5 Nb alloy at the nanoscale and understand the diffusion of deuterium from the water-oxide interface to the base metal. Results indicate that defects, nanoporosity and microcracks in the oxide govern the oxidation tendency of Nb, which has +5, +4, +2, or partially oxidized states. Deuterium transport through the oxide layer is also directly correlated with defect density. The concentration of deuterium is highest at the water-oxide interface and lowest at the metal-oxide interface. This correlates with a change in defect density and Nb oxidation state, which also decreases between these two interfaces. The present findings provide a mechanistic understanding of oxidation and deuterium ingress in Zr-2.5 Nb alloys, helping to ensure the long-term performance of the material for reactor applications. • Nanopore density increases with exposure duration from 600 to 1799 days. • Deuterium concentration varies in the oxide layer and is influenced by nanoporosity. • β-phase impedes deuterium diffusion, impacting hydrogen pickup in Zr-2.5 Nb alloy.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".