National Research Nuclear University “MEPhI” (Moscow Engineering Physics Institute), Moscow, Russia:

Yu. A. Perlovich, Professor, e-mail: yuperl@mail.ru
M. G. Isaenkova, Professor
V. A. Fesenko, Researcher
P. N. Medvedev, Engineer

X-ray diffractometric methods investigated the cladding pipes, made of Zr – 1%Nb alloy, manufactured from spongy and electrolytic zirconium and oxidized at high temperature (1100 ^оC). The layer-by-layer study of oxide phase composition was investigated together with structural and textural peculiarities of pipe layers, adjacent to oxidation zone. According to the enterprise-adopted criteria, preliminary recrystallization of both pipes is complete. The whole deformed matrix is replaced by newly formed recrystallized grains. However, the size of these grains can be significantly varied, depending on the density of recrystallization nucleus distribution and their growth rate, certainly differing in alloys, based on spongy and electrolytic zirconium. A number of X-ray data testifies, that recrystallization of investigated pipes proceeds in different manners, with formation of new different size grains. The defined difference in recrystallized grain sizes is critical for the pipe completeness with high-temperature oxidation. Electrolytic zirconium pipe destruction is connected with prevalence of tetragonal phase in its oxide layer. This is explained by intense diffusion of oxygen into pipe wall, subjected to recrystallization with final thermal treatment with formation of more fine-grain structure, than spongy zirconium pipe.

1. Goryachev A. V., Kosvintsev Yu. Yu., Leshchenko A. Yu. Fizika i khimiya obrabotki materialov = Physics and Chemistry of Materials Treatment. 2009. No. 2. pp. 14–23.
2. Yegorova L., Lioutov K., Jouravkova N., Konobeev A., Smirnov V., Chesanov V., Goryachev A. Experimental Study of Embrittlement of Zr – 1 % Nb VVER Cladding under LOCA-Relevant Conditions. US Nuclear Regulatory Commission. Available at: http://pbadupws.nrc.gov/docs/ML0511/ML051100343.pdf.
3. Borodkina M. M., Spektor E. N. Rentgenograficheskiy analiz tekstury metallov i splavov (X-ray analysis of metal and alloy texture). Moscow : Metallurgiya, 1981. 271 p.
4. Zavodchikov S. Yu., Zuev L. B., Kotrekhov V. A. Materialovedcheskie voprosy proizvodstva izdeliy iz splavov tsirkoniya (Material science tasks of manufacturing of zirconium alloy products). Novosibirsk : Nauka, 2012. pp. 197–233.
5. Isaenkova M. G., Perlovich Yu. A., Fesenko V. A. Sovremennye metody eksperimentalnogo postroeniya teksturnykh pryamykh polnykh polyusnykh figur po rentgenovskim dannym (Modern methods of experimental construction of texture straight complete polar figures according to the X-ray data). Zavodskaya laboratoriya. Diagnostika materialov = Industrial laboratory. Diagnostics of materials. 2013. Vol. 79, No. 7, Part 1. pp. 25–32.
6. Voytovich R. F. Okislenie tsirkoniya i ego splavov (Oxidation of zirconium and its alloys). Kiev : Naukova Dumka, 1989. 288 p.
7. Krymskaya O., Isaenkova M., Perlovich Yu. Determination of Grain Size for Different Texture Components by Statistical Fluctuations of Intensity Registered in the Course of Texture Measurement. Solid State Phenomena. 2010. Vol. 160. pp. 135–140.
8. Perlovich Yu., Isaenkova M. Development of Texture and Substructure Inhomogeneity by Recrystallization of Rolled Zr-Based Alloys. In book: Recrystallization. Edited by K. Sztwiertnia. Rijeka : InTech, 2012. pp. 3–22.
9. Perlovich Y., Isaenkova M. Distribution of c- and a-Dislocation in pipe of Zr alloys. Metallurgical and materials transactions. 2002. Vol. 33A. pp. 867–874.