Finite Element Analysis of Crush Test for Helical Spring Coils Used in CANDU Fuel Channel Spacers
Bibliographic record
Abstract
Abstract CANDU fuel channel annulus spacers made of a coiled spring are designed to maintain an annular gap between the pressure tube and calandria tube throughout the operating life of the reactor. The integrity of spacers is essential for avoiding pressure tube contact with the calandria tube that could lead to hydride blister formation and possible pressure tube failure. Spacers made of Inconel X-750 material are degrading over time due to irradiation damage. The yield strength, ultimate tensile strength, and ductility for irradiated Inconel X-750 spacers are important parameters for fitness-for-service demonstration of spacers operating under later life conditions. In the absence of the standard tensile test specimens for measuring tensile properties of in-service spacer coil material, quantitative load and displacement data captured from crush tests can be used to approximately estimate the tensile properties of degraded Inconel X-750 annulus spacers. The yield strength is estimated from the crush test by the maximum circumferential stress on the inner surface determined by the analytical solutions at the point of applied load when the linear portion of a test record of load versus displacement curve deviate from the linear trend. However, serval uncertain effects in the crush test may affect this estimation. Three-dimensional finite element analyses have been performed to simulate the crush tests of ex-service annulus spacer made of Inconel X-750 material to investigate the effects of end coils and frictions on extracting the initial material yield strength from the crush tests by the simplified analytical solutions. The finite element analysis observations have been compared with these simplified solutions to validate the current yield strength estimates obtained from crush tests.
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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".