Mechanisms of the Cladding Tubes Axial Cracking in Power Ramp Tests

• Published in: Physics of atomic nuclei Vol. 85; no. 12; pp. 1972 - 1980
• Main Authors: Novikov, V. V., Plyasov, A. A.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.12.2022; Springer; Springer Nature B.V
• Subjects: Alloys; Claddings; Cracking (fracturing); Hydrogen embrittlement; Inspection; Nuclear facilities; Nuclear fuel elements; Nuclear Reactor Safety; Nuclear reactors; Particle and Nuclear Physics; Physics; Physics and Astronomy; Radiation hardening; Tubes; Zirconium; Zirconium alloys; Zirconium base alloys; fuel cladding; power ramp; longitudinal crack; mechanisms of embrittlement; delayed hydride cracking; hydrogen embrittlement; E110; zirconium alloy
• ISSN: 1063-7788; 1562-692X
• DOI: 10.1134/S1063778822110059

In the early 1990th the research program to investigate experimental fuel rods with different fuel compositions and claddings in the research reactor MIR was carried out by JSC “SSC Research Institute of Atomic Reactors” and JSC “VNIINM”. Reexamination of the program reports containing results of post-irradiation tests allows ascertaining that some rods with the zirconium alloy E110 cladding tubes were subjected to the power ramp conditions. As a result some rods failed, but one of them demonstrated axial cracking from one end to the other. Unpublished results of the damaged fuel rods inspection are presented here. Different mechanisms of the cladding tubes axial cracking have been analyzed. It is shown that the key factors for axial cracking of claddings after power ramps are hydrogen embrittlement and radiation hardening of a material. However, to the moment it is not enough information to exactly select which mechanism of cladding failure was realized.