Manufacturing Variability, Microstructure, and Deformation of Zr-2.5Nb Pressure Tubes
Bibliographic record
Abstract
Abstract The time-dependent deformation behavior of pressure tubes in CANDU™ (CANada Deuterium Uranium) reactors is an important property that has to be predicted for reactor life management. Measurements accumulated over many years have shown that there is considerable variability in deformation rates between different tubes. The deformation behavior not only varies from tube to tube but also varies along the length of each tube; this axial variation in itself is unique to each tube. The deformation behavior is determined by the microstructure and this is a function of the manufacturing history. An exhaustive study has been conducted to collect and compile deformation and manufacturing data for tubes in many different reactors. The manufacturing data have been analyzed with respect to the measured in-reactor performance of the pressure tubes. Data from pressure tubes fabricated over a 30-year period have been analyzed. During this time the manufacturing parameters have evolved to improve the workability and mechanical properties and also reduce tube-to-tube variability. The effect of manufacturing variables on in-reactor performance has been assessed for tubes that have been in service for many years and approaching the end of their design life. The analysis shows that the two most important factors that affect the deformation behavior of pressure tubes are the material source (ingot) and the extrusion conditions. These are related by the microstructure (texture, grain size, and dislocation density) to the deformation. The results of the statistical analyses will be presented and discussed in terms of the manufacturing conditions that bring about specific microstructures.
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 | 0.001 | 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 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".