Measuring Deformations in a CANDU 6 Concrete Containment Structure
Bibliographic record
Abstract
The CANDU TM 6 reactor system is contained within a post-tensioned concrete containment structure.The New Brunswick Power (NBP) owned, Point Lepreau CANDU TM 6 Generating Station (PLGS) located in New Brunswick, Canada, has been in service since 1983.Investigations are being undertaken to evaluate the significance of any age-related degradation.Particularly, a survey is being conducted to assess the expected long term performance of the structure.For part of this survey, in-situ deformations that occur during normal reactor operation and a leak-rate test, for which the structure is internally pressurized, are being measured.During the early life of the structure, deformations were measured using both embedded and surface mounted gauges on the concrete surfaces.The record shows that neither of these strategies provided results which can be used to evaluate the current stress conditions.A reason for this may be related to the type of instrumentation used.Subsequently, various types of commercially available instruments have been appraised for application at PLGS.Laboratory and in-situ tests on mechanical, vibrating wire and fibre-optic deformation measuring devices confirm that the accuracy of the measurements can be expected to vary significantly between instrument types.In addition, for each instrument type, the instrument stiffness, the temperature and the manner in which the instrument is installed all strongly influence output.Recently, three gauge types were retrofitted to the outside surfaces of the PLGS containment structure to provide a further assessment of the usefulness of the instrumentation and, ultimately, the condition of the structure.Taking the determining factors of instrument type and environment into account, measurements were made during and following a leak-rate test.These tests have shown that all of the instrument types can be used to assess the condition of the structure.It is shown that concrete containment structure is required to endure distortional stresses due to environmental conditions.It is concluded that monitoring of deformations occurring in concrete containment structures during the leak-rate pressure tests as well as continuously over the period of their operating life is an essential element in a structural ageing management program. BACKGROUNDIn the mid 1990's, Atomic Energy of Canada Limited (AECL) and New Brunswick Power (NBP) initiated a series of investigations to determine the neeA for a Plant Life Management Program (PLiM) at Point Lepreau Generating Station.Recently, a program was designed to provide the basis for a statement of "fitness for service" for the structures partially through measurements on the concrete containment.The plan included activities designed to provide details for an ageing management program (AMP) and an assessment of the condition of the structures.The physical installation of instrumentation on the concrete containment structure was required for both of these purposes.Part of the proposed in-situ work was recently completed.This paper presents a summary of the ageing management program, the physical condition survey and the monitoring scheme designed to evaluate the effects of age-related change, if any, for the containment structure.The monitoring program carried out during and following a leak rate pressure test is briefly described.For the latter, instruments were installed on the exterior surfaces of the containment structure at PLGS, and measurements were taken during a leak-rate (pressure) test.A brief summary of some of the test results is presented.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".