Post-irradiation Examination of the Lower Part of the Phébus FPT2 Degraded Bundle
Bibliographic record
Abstract
The Phébus PF project is an international programme examining the release behaviour of fission products from irradiated fuel. It is led and being carried out by the French Institut de Radioprotection et de Sûreté Nucléaire (IRSN) at Cadarache in collaboration with the European Commission, EU national research institutes as well as USA, Canada, Korea, Japan and Switzerland. The FPT1 test examined bundle degradation and release under steam atmosphere while FPT2 was carried out under steam-limited conditions. After an initial campaign of macrophotography and examination of the major features of the degraded bundle at ITU, the PIE (Post Irradiation Examinations) continued with the extraction of six selected sites from different levels to perform microscopic examination and analysis of the structures found there. This paper reports on the initial findings in the lower part of the bundle. The macroscopy confirmed the state of the bundle determined by the immediate post-test X-ray and ¿ tomographies carried out at Cadarache. The bundle, as in previous tests, had a characteristic central cavity and a corium pool at one-third height of the bundle, while the upper part showed substantial oxidation, damage and distortion. The corium pool extended the full width of the bundle and appeared to be deeper than that of FPT1. The corium appears to be fully oxidic and has similar amounts of uranium and zirconium with traces of fission products, structural materials and shroud material. Beneath the pool, the cladding was still substantially oxidized and distorted with some fuel-cladding interaction. There was considerable debris beneath the bundle including zones of corium as well as melted metallic structures that probably originated from cladding and reactor structural materials. The extent of damage indicated that the most extreme temperatures were not achieved at this level.
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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.003 | 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".