ASSESSMENT OF DELAYED HYDRIDE CRACKING IN CANDU PRESSURE TUBE USING THE PROCESS ZONE WITH CREEP EQUATION FROM ARTIFICIAL NEURAL NETWORK MODELLING
Bibliographic record
Abstract
The pressure tubes of the CANDU 600 nuclear power plant at CNE Cernavoda Romania are made of Zr-2.5%Nb alloy, which is susceptible to hydrogen accumulation during normal operation. As part of the work, structural integrity analyses will be performed regarding the initiation of the Delayed Hydride Cracking (DHC) phenomenon at the complex flaws in the pressure tubes, which can be detected by the periodic inspections performed on the fuel channels. These flaws are described by the Canadian standard CAN/CSA N285.8 as a combination of a Bearing Pad Fretting Flaw (BPFF) with a Debris Fretting Flaw (DFF). The analysis of the mechanical stresses and strains field is obtained by finite element analysis (FEA) in the process zone of the flaws, that are located on the inner surface of the CANDU pressure tube. The work develops a method based on FEA, regarding the evaluation of the phenomenon of mechanical stress relaxation by creep in the process zone of flaws for the time interval between two periodic inspections of the CANDU fuel channels. This method allows obtaining the relaxation of mechanical stresses, by inserting the explicit function of the radial strain rate of the CANDU pressure tube (Zr-2.5%Nb alloy) into the algorithm for obtaining iterative numerical solutions in creep. The explicit function was obtained by the Multilayer Feedforward Neural Network (MFNN) method under the conditions of irradiation in-service specific to the CANDU fuel channels. The results of the work are used in the assessment of structural integrity by analysing the prevention of DHC initiation in the pressure tubes of a CANDU plant.
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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 | 0.002 | 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".