International Journal of Environmental Science and Development

Abstract—Recycling of Zr-Nb-Sn-Fe scraps in casting enhances the price competitiveness of nuclear-grade Zr alloys and accordingly the energy from nuclear power plants. Increasing the fraction of scrap in casting of new alloy ingots increases the price competitiveness, but it aggravates the deformability and mechanical reliability of cast alloys. In this study, the effect of scrap ratio on the mechanical reliability of Zr-Nb-Sn-Fe alloys was studied. The increase of scrap fraction in casting increases the oxygen content in the ingot and nuclear claddings fabricated from cast ingots. The increase of oxygen content is caused by the surface oxide of scraps such as small pieces of turning, chips, etc. Iron content was not found to increase appreciably with the increasing fraction of scrap because scraps were well kept in the iron-free container. The microstructure of ss-cast Zr alloy with increasing fraction of scraps displayed plate/or needle α phase and the microstructural features were observed to be affected by increase of scrap fraction. The strength increases with increasing fraction of scrap, which can be attributed to the increase of oxygen content. The ductility decreased slightly with increase of scrap fraction. The strength increased at the expense of ductility with increase of scrap fraction. In some ingots, iron oxide flakes were intentionally added to explore the effects of iron oxide which may be added from the scarp storage container. The alloys with the addition of iron oxide flakes exhibited the drastic decrease of the formability and exhibited the brittle fracture behavior during rolling. The increase of oxide fraction increased the oxidation resistance because of high oxygen content the matrix may have prevented oxygen diffusion into matrix.

Index Terms—Zr-Nb-Sn-Fe, scrap, recycling, nuclear energy, oxygen, ductility.

Jae Sook Song is with Nano Engineering Research Cener, Chungnam National University, Daejon 34134, South Korea (e-mail: jsongdoctor@hanmail.net).
Sun Ig Hong is with Materials Science and Engineering Department, Chungnam National University, Daejon 34134, South Korea (e-mail: sihong@cnu.ac.kr).

[PDF]

Cite: Jae Sook Song and Sun Ig Hong, "Recycling Zr-Nb-Sn-Fe Scrap in Casting of Nuclear-Grade Alloy Ingots and Its Effects on Mechanical Performance and Integrity," International Journal of Environmental Science and Development vol. 11, no. 2, pp. 84-88, 2020.

Copyright © 2020 by the authors. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).