Revealing abnormal micro- and macro-structure evolution mechanism of porous pyrolytic carbon in TRISO coated fuel particles under high-temperature treatment

Revealing abnormal micro- and macro-structure evolution mechanism of porous pyrolytic carbon in TRISO coated fuel particles under high-temperature treatment | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 11 February 2026 V1 Latest version Share on Revealing abnormal micro- and macro-structure evolution mechanism of porous pyrolytic carbon in TRISO coated fuel particles under high-temperature treatment Authors : Jinhong Lei , Xu Yang , Hongsheng Zhao 0000-0002-6829-3204 [email protected] , Xing Cheng , Hui Yang , Kaihong Zhang , Hao Yu , Xiaoxue Liu , and Bing Liu Authors Info & Affiliations https://doi.org/10.22541/au.177077171.13186432/v1 76 views 33 downloads Contents Abstract Supplementary Material Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Porous pyrolytic carbon (PPyC) serves as a buffer layer in tri-structural isotropic (TRISO) coated particles for nuclear fuel. However, its unique low-density and porous structure leads to unclear high-temperature structure evolution behaviors, which are significantly distinct from those of dense pyrolytic carbon. Herein, PPyC was subjected to heat treatments at temperatures ranging from 1200°C to 1600°C, respectively. Results clearly identify 1400°C as the key structure-performance evolution threshold. Below this temperature, oxygen defect migration dominates structural evolution, while above it, transition zones between amorphous and crystalline domains generate abundant vacancies, and grain boundary pinning restricts atomic motion and raises structural disorder. These changes are accompanied by the reduction of PPyC particle size, reversible open-closed pore conversion mediated by particle swelling and sintering-induced coalescence, and significant layer shrinkage at the macroscale. This work systematically clarifies the high-temperature structural evolution mechanism of PPyC, effectively fills the existing gap in low-density pyrolytic carbon evolution theory, and provides valuable theoretical support for the optimal design of TRISO particles and other high-performance novel functional carbon material. Supplementary Material File (maindocument.pdf) Download 6.79 MB Information & Authors Information Version history V1 Version 1 11 February 2026 Copyright This work is licensed under a Non Exclusive No Reuse License. Keywords high temperature treatment microstructure evolution pore evolution porous pyrolytic carbon triso coated fuel particles Authors Affiliations Jinhong Lei Tsinghua University View all articles by this author Xu Yang Tsinghua University View all articles by this author Hongsheng Zhao 0000-0002-6829-3204 [email protected] Tsinghua University View all articles by this author Xing Cheng Tsinghua University View all articles by this author Hui Yang Tsinghua University View all articles by this author Kaihong Zhang Tsinghua University View all articles by this author Hao Yu Tsinghua University View all articles by this author Xiaoxue Liu Tsinghua University View all articles by this author Bing Liu Tsinghua University View all articles by this author Metrics & Citations Metrics Article Usage 76 views 33 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Jinhong Lei, Xu Yang, Hongsheng Zhao, et al. Revealing abnormal micro- and macro-structure evolution mechanism of porous pyrolytic carbon in TRISO coated fuel particles under high-temperature treatment. Authorea . 11 February 2026. DOI: https://doi.org/10.22541/au.177077171.13186432/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu . 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