Seismic Qualification of Rocking Objects in Canadian Nuclear Power Plants
Bibliographic record
Abstract
Canadian Nuclear Standards CSA N289.1 and CSA N289.3 govern the seismic qualification of structures, systems and components in Nuclear Power Plants (NPPs). These standards provide a generic response spectrum, similar to the NBK spectrum developed by Newmark, Blume and Kapoor, representing the peak response of a family of Single Degree of Freedom (SDOF) oscillators to be the design basis of new NPPs. These standards, however, do not provide any guidance on seismic qualification of unanchored rocking objects in a NPP. In order to simplify the design, the current practice is to convert a rocking object in to an equivalent SDOF oscillator to obtain the acceleration from the applicable response spectrum leading to the static force at the center of gravity of the rocking object. This method has been criticized in the literature and various approaches have been suggested by different authors based on the equations of motion of rocking objects. In a NPP, the objects requiring the rocking analysis vary from small tool cabinets to large components such as turbine rotors weighing more than 150 tons. Sometimes, qualification of rocking masonry as a single unit or as a frame is also required to be carried out. Small objects can be treated as single rocking objects whereas the large ones with two or more supports would be treated as rocking frames. The problem of rocking analysis is further enhanced when two NPPs, located on the same site, have drastic difference in the frequency content of their seismic events. This happens when one of the two plants is assessed for the east coast response spectrum (known as East North American (ENA) spectrum in Canada) based on the latest research whereas the other one is designed on the basis of the west coast response spectrum similar to the NBK spectrum. In such situations, universal qualification of rocking objects for both the plants becomes challenging. This paper categorizes rocking objects into various categories and provides a road map on finding solutions to rocking problems in Canadian NPPs.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".