Contribution to the understanding of brittle fracture conditions of zirconium alloy fuel cladding tubes during LOCA transient

JOURNAL OF NUCLEAR MATERIALS

卷:527

Article

Thieurmel, Ronan^1,2  Besson, Jacques¹  Pouillier, Edouard²  Parrot, Aurore²  Ambard, Antoine²  Gourgues-Lorenzon, Anne-Francoise¹ 

[1] PSL Univ, MAT Ctr Mat, UMR CNRS 7633, MINES ParisTech, BP 87, F-91003 Evry, France

[2] MMC Dept, EDF R&D, Ave Renardieres, F-77818 Ecuelles, Moret Sur Loing, France

关键词: Fuel cladding;    Zirconium alloys;    LOCA;    Reflooding;    Microstructure;    Oxidation;    Fracture;    Secondary hydriding;    Semi-integral test;   

DOI  :  10.1016/j.jnucmat.2019.151815

来源: Elsevier

【 摘 要 】

This work addressed fracture mechanisms of nuclear fuel claddings in hypothetical Loss-Of-Coolant-Accident (LOCA) conditions. To this aim, laboratory-scale semi-integral thermal-mechanical tests were carried out, using an oxidation temperature of 1200 degrees C, slow cooling down to 700 degrees C and a final quench by reflooding under an axial load. Two fracture mechanisms were observed. Fracture in the burst zone was due to oxide formation and subsequent transformation of ductile beta into brittle oxygen-enriched alpha(O). The second fracture mechanism affected a region both enriched in oxygen and in hydrogen due to secondary hydriding. In the investigated conditions, fracture location was independent of burst morphology, oxidation time and axial loading. A fracture scenario as a function of the reflooding transient was proposed. Physical fracture mechanisms were elucidated with respect to microstructural evolution in these two regions. Based on the local distribution of chemical elements and phases, a fracture threshold function of the local, layered microstructure was suggested for each fracture location. (C) 2019 Elsevier B.V. All rights reserved.

【 授权许可】

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