Spark plasma sintering of urania-thoria duplex fuel pellets
Bibliographic record
Abstract
• Difference in phase shrinkage rates causes excessive stress and cracking in pellets. • High interfacial bonding and macro cracking was seen in SPS duplex pellets. • Conventionally sintered pellets cracked in the urania only, due to no interfacial bonding. • Clearances of 0.33 mm reduced the cracking in conventionally sintered duplex pellets. Thoria (ThO 2 ) is an alternative fuel to the commonly used urania (UO 2 ) nuclear fuel, showing promising accident tolerance as well as sustainability through its higher abundance in the earth’s crust and reduced spent fuel waste burden. Unlike urania, thoria is a fertile fuel material, so fuel researchers had to develop innovative ways to utilize thoria. One such concept is a thoria-cored urania duplex fuel, composed of a thoria core slotted into a urania annulus, that could replace solid urania fuel in currently operational commercial reactors. The fabrication of this fuel is challenging due to the mismatch in thermal expansion and densification shrinkage rates of the thoria and urania parts. In this study, a novel Spark Plasma Sintering (SPS) technique was used to test the fabrication of duplex fuel pellets. Although the spark–plasma–sintered duplex pellets were seen to fracture similarly to pellets produced using Conventional Sintering (CS), the interfacial bonding between thoria and urania improved during SPS in comparison to CS. The results indicate that SPS was not a viable alternative for preparation of duplex pellets, although there was improvement in the bonding between urania and thoria compared to CS.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.000 |
| 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) | 0.000 | 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 teacher head, 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".