Fitness-for-Service Assessment of Calandria Tube to Liquid Injection Shutdown System Nozzle Contact in a CANDU Reactor
Bibliographic record
Abstract
In CANDU1 reactors, calandria tubes are used to separate the fuel channels from the moderator. The Liquid Injection Shutdown System (LISS) nozzles, which contain holes for discharging neutron-absorbing liquid into the moderator, are arranged perpendicularly in the gap between adjacent rows of calandria tubes. Both calandria tubes and LISS nozzles sag during service due to creep, with the more heavily loaded calandria tubes sagging relatively more. When contact between a calandria tube and a LISS nozzle has been detected by in-service inspection, or is predicted to occur, a fitness-for-service assessment is permitted by CSA Standard N285.4 to demonstrate acceptability of continued operation until the end of the next periodic inspection interval, provided that the fitness-for-service assessment is acceptable to the Regulatory Authority. A fitness-for-service assessment has been recently performed for a calandria tube and a LISS nozzle that were predicted to contact at a future time. The assessment has demonstrated that for an evaluation period of three years after the predicted contact time, the structural integrity of the calandria tube and the LISS nozzle is maintained, both components will continue to function in accordance with their design requirements, and their contact will not result in contact between the calandria tube and a pressure tube.
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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 | 0.000 | 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) | 0.000 | 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".