In the core of Nuclear Power Plant (NPP) reactors, Zirconium alloys have been widely used as the fuel-rod cladding material. However, during nuclear power plant operation they suffer some important weaknesses which lately leads to minimize the ageing and the nuclear safety of the NPP. One the other hand, some alloys are required to achieve good mechanical and thermal properties of the Zirconium. These alloys are all alloying with a certain amount of Fe. Zr-Fe system has received much attention in the past decades, it has been examined the existing phase diagrams of Zr-Fe [1-2]. Lumley et al [3] has confirmed that Fe atoms occupy octahedral interstitial (O) sites and proven also that the formation energy for intermetallic phase of Zr₂Fe is metastable. The effect of Fe impurity on mechanical properties of the cladding material is remarkable, which can improve and achieve good mechanical properties in term of hardness and compressibility; the volume expansion and thermal expansion are obviously changed at height temperature. These variations are related to the iron impurity where it was put in the octahedral interstitial site of Zr Supercell (2x2x2).

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References

[1] K. Linga Murty and I. Charit, Texture Development and Anisotropic Deformation of Zircaloys, Prog. Nucl. Energy, 2006, 48(4), p 325–359.

[2] A.T. Motta et al., Zirconium Alloys for Supercritical Water Reactor Applications: Challenges and Possibilities. Nucl. Mater., 2007, 371(1–3), p 61–75.

[3] S.C. Lumley, S.T. Murphy, P.A. Burr, R.W. Grimes, P.R. Chard-Tuckey, M.R. Wenman, J. Nucl. Mater. 437 (2013) 122–129.