Observations from Several Condition Assessments of Prestressed Concrete Cylinder Pipe Used at Energy Generation Facilities
Bibliographic record
Abstract
Golder Associates Inc. has conducted several condition assessments of prestressed concrete cylinder pipe (PCCP) used in the cooling water systems of energy generation facilities. This paper presents observations from these condition assessment projects. A vital component to the operation of energy generation facilities is the cooling water system. The cooling water system conveys cool water from a river or basin through the plant's condensers to condense steam produced in the process of power generation. The heated water is then returned to the river or basin, or sent through cooling towers to dissipate the gained heat. To work effectively, these systems typically operate with high flows (greater than 200,000 gpm) and low pressures (less than 60 psi) in large diameter pipelines (typically 54 to 120 in). These systems may provide cooling water to one or more units, and redundancy is not typical. Thus, the isolation of these systems for evaluation or repair may require the temporary shutdown of one or several units, resulting in significant costs associated with purchasing replacement power. Many utilities operating energy generation facilities constructed in the 1970s and 1980s have not included these cooling water systems in their general plant evaluation and maintenance schedule, and these systems have often operated continuously for over 30 years. Due to the increased awareness of plant personnel, and the age of their buried infrastructure, these systems are now being evaluated. Condition assessment of these systems is similar to other pipelines with tasks such as document review, physical evaluation and condition summary, but also requires detailed planning to coincide with planned unit outages, and in some cases requires significant coordination with other facilities to allow for several unit outages at the same time. Pipeline condition assessments conducted have identified a wide range of conditions for the 30- to 40-year-old PCCP used in cooling water systems, ranging from pristine pipe, to pipe that has technically failed. Factors contributing to the distress observed in the pipelines include the manufacturing practices (particularly the use of class IV prestressing wire), installation practices, nearby stray electric currents, groundwater quality and interaction, and operational stresses. Recommendations from these condition assessments have also varied greatly, from continued evaluation, instituting operational controls, or even complete replacement of distressed portions of the line.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".