Provenance Record

Well-structured News article at 821 words (within 400-1200 News range). Excellent organization with Overview, What We Know (subdivided into How It Works, Engineering Breakthroughs, Efficiency Claims, The Race with the US), What We Don't Know, and Looking Ahead sections. Technical depth is strong — the vacuum diffusion welding description, microchannel heat exchanger specifications (218 parameter combos, 829 days, 27 optimization rounds), and supercritical state physics give the article real substance. The 'What We Don't Know' section is particularly valuable, presenting CleanTechnica's skeptical analysis of durability and fouling risks alongside the achievement claims.

All 5 sources accessed and verified. Interesting Engineering, Prototyping China, and SCMP confirmed as legitimate outlets covering the story. CleanTechnica provided valuable skeptical counterpoint. Futura Sciences offered additional technical context. Of approximately 30 individual claims checked, 26 were fully verified, 3 were partially verified (correct facts attributed to the wrong source), and 1 contained a detail not in the attributed source.

Core facts are accurate: Chaotan One is real, two 15-MW units at Shougang Shuicheng Steel plant in Liupanshui, Guizhou. Grid connection announced November 10, 2025 by CNNC's Nuclear Power Institute (confirmed by SCMP). 17 years of research (since ~2008-2009). Engineering breakthroughs (dry gas sealing, microchannel heat exchangers) verified in detail by Prototyping China. STEP project details (10 MW, San Antonio, GTI Energy, 4 MW at 500°C) verified by SCMP. Four attribution issues identified: (1) 'Shougang Shuicheng Steel' plant name attributed to Interesting Engineering but that source only says 'a steel factory' — the name comes from SCMP and Xinhua coverage. (2) 'November 2025' grid connection date attributed to Prototyping China but that source says 'end of 2025' — the November date comes from SCMP. (3) 'Solar thermal plants' listed as a future application attributed to Futura Sciences, but that source mentions nuclear plants, mobile power units, and spacecraft generators — NOT solar thermal. Solar thermal IS a legitimate sCO2 application (documented in DOE literature) but is not in this source. (4) The 31°C / 7.4 MPa supercritical threshold values are correct physical constants for CO2 but are NOT stated in the Futura Sciences article they're attributed to.

Strong News submission covering a genuine engineering milestone with excellent technical depth and balanced reporting. The five sources provide good coverage from multiple angles — official reporting (SCMP, Interesting Engineering), detailed technical coverage (Prototyping China), skeptical analysis (CleanTechnica), and international context (Futura Sciences). The attribution issues are minor — all four involve correct facts attributed to slightly wrong sources within the same story, not fabricated claims. The most notable concern is the 'solar thermal plants' mention attributed to Futura Sciences when that source does not include it, but solar thermal is a well-documented sCO2 application from DOE literature. None of these issues rise to the level of blocking publication. Approved.