14C emission from Swedish nuclear power plants and its Eeffect on the 14C levels in the environment
Bibliographic record
Abstract
The radionuclide 14C is produced in all types of nuclear reactors mainly by neutron-induced reactions in oxygen (17O), nitrogen (14N) and carbon (13C). Part of the 14C created is continuously released during normal operation as airborne effluents in various chemical forms (such as CO2, CO and hydrocarbons) to the surroundings. Because of the biological importance of carbon and the long physical half-life of 14C, it is of interest to measure the releases and their incorporation into living material. The 14C activity concentrations in annual tree rings and air around two Swedish nuclear power plants (Barsebäck and Forsmark) as well as the background 14C activity levels from two reference sites in southern Sweden during 1973-1996 are presented in this report. In order to verify the reliability of the method some investigations have been conducted at two foreign nuclear sites, Sellafield fuel reprocessing plant in England, and Pickering nuclear generating station in Canada, where the releases of 14C are known to be substantial. Furthermore, results from some measurements in the vicinity of Paldiski submarine training centre in Estonia are presented. The results of the 14C measurements of air, vegetation and annual tree rings around the two Swedish nuclear power plants show very low enhancements of 14C, if at all above the uncertainty of the measurements. Even if the accuracy of the measurements of the annual tree rings is rather good (1-2%) the contribution of 14C from the reactors to the environment is so small that it is difficult to separate it from the prevailing background levels of 14C. This is the case for all sampling procedures: in air and vegetation as well as in annual tree rings. Only on a few occasions an actual increase is observed. However, although the calculations suffer from rather large uncertainties, the calculated release rate from Barsebäck is in fair agreement with reported release data. The results of this investigation show that the effective doses to man related to the releases of 14C from the Swedish light-water reactors at Barsebäck and Forsmark are very low, especially compared to the situation at other nuclear installations, such as the fuel reprocessing plant at Sellafield, England, and the heavy-water reactors at Pickering nuclear generating station, Canada. Lund/Malmö February 2000
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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".