Stress rupture of SiC/SiC composite tubes under high‐temperature steam. Issue 3 (3rd December 2022)

• Record Type: Journal Article
• Authors: Koyanagi, Takaaki; Karakoc, Omer; Hawkins, Charles; Lara‐Curzio, Edgar; Deck, Christian; Katoh, Yutai
• Is Part Of: International journal of applied ceramic technology. Volume 20:Issue 3(2023)
• Page Start: 1658
• Page End: 1666
• Publication Date: 2022-12-03
• Subjects: composites -- corrosion/corrosion resistance -- oxidation -- silicon carbide; Ceramics -- Periodicals; Ceramics -- Technological innovations -- Periodicals; 620.1405
• DOI: 10.1111/ijac.14283
• Languages: English
• ISSNs: 1546-542X

Abstract

Abstract: SiC‐fiber–reinforced SiC matrix composite cladding for light water reactor fuel elements must withstand high‐temperature steam oxidation in a loss‐of‐coolant accident scenario (LOCA). Current composite designs include an outer monolithic SiC layer, in part, to increase steam oxidation resistance. However, it is not clear how such a structure would behave under high‐temperature steam in the case when the monolithic layer cracks and carbon interphases and SiC fibers are exposed to the environment. To fill this knowledge gap, stress‐rupture tests of prototypic SiC composite cladding at 1000°C under steam and inert environments were conducted. The applied stress was ∼120 MPa, which was beyond the initial cracking stress. The failure lifetime under steam was 400–1300 s, while 75% of the composite specimens did not fail after 3 h of total exposure under inert gases. Microstructural observations suggest that steam oxidation activated slow crack growth in the fibers, which led to failure of the composite. The results from this study suggest that stress rupture in steam environments could be a limiting factor of the cladding under reactor LOCA conditions. Abstract : Stress rupture experiment of SiC/SiC composite tubes at 1000°C with 100% steam at atmospheric pressure, releveling the material degradation.