Unsteady two-dimensional multiphysical simulation of a pressure tube model expanded to contact with the outer concentric tube
Bibliographic record
Abstract
For the blind calculation of the International Collaborative Standard Problem (ICSP) experiment on heavy water reactor moderator subcooling requirements, the COMSOL Multiphysics code is used to simulate plastic deformation of a pressure tube (PT) as a result of the interaction of stress and temperature. It is shown that the thermal stress model of COMSOL is compatible to simulate the multiple heat transfers (including the radiation heat transfer and heat conduction) and stress strain in the simplified two-dimensional problem. The benchmark test result for radiation heat transfer is in good agreement with the analytical solution for the concentric configuration of PT and calandria tube (CT). Since the original strain model of COMSOL only considers an elastic deformation with thermal expansion coefficient, the PT/CT contact cannot be predicted in the ICSP. Therefore, the plastic deformation model by the Shewfelt and Godin, widely used in the fuel channel analysis of CANadian Deuterium Uranium (CANDU) reactor, is implemented to the strain equation of COMSOL. The heat-up of PT, the strain rate, and the contact time of the PT/CT are calculated with the boundary conditions (BCs) given for blind calculation of the ICSP experiment.The result shows a sudden expansion of the inner concentric PT within a few milliseconds. This unsteady simulation should be helpful for the conceptual design of experiment as well as for the understanding of multiphysics inside the fuel channels of the CANDU reactor.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 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 source (direct Gemma or distilled Codex), 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".