In October 2026, four papers co-authored by lecturers of Department No. 9 were published. Click on a paper title to open its description.
1. Helium swelling of 16Cr15Ni austenitic steel (Advances in Nuclear Science and Applications)
M. S. Staltsov, P. Z. Ngcobo, C. L. Ndlangamandla, S. C. Masikane, S. Ngongo, H. S. Nyembe, I. I. Chernov, M. K. Tirago. Study of austenitic steel 16Cr15Ni microstructure after helium ion irradiation along ion trajectory. Advances in Nuclear Science and Applications, 2026, 2(3), 224–235. https://doi.org/10.63907/ansa.v2i3.93
The microstructure of 16Cr15Ni austenitic steel irradiated with 40 keV helium ions to a fluence of 5·1020 m−2 was studied by transmission electron microscopy, comparing the effects of irradiation temperature and prior heat treatment on porosity and gas swelling. The highest swelling was found in the sample annealed after quenching and irradiated at 650 °C, the lowest in the quenched sample. Specimens prepared by focused ion beam (FIB) showed somewhat higher porosity and swelling than electropolished ones, so FIB preparation gives a more accurate picture of radiation damage.
2. Recrystallization degree from synchrotron Debye rings (Materials Characterization)
O. A. Krymskaya, M. G. Isaenkova, V. A. Fesenko, M. I. Petrov, R. D. Svetogorov. Determination of the recrystallization degree by fragmentation of Debye rings obtained with synchrotron radiation. Materials Characterization, 2026, 241, 117209. https://doi.org/10.1016/j.matchar.2026.117209
There is still no standard way to measure the recrystallization degree, the volume fraction of grains with a defect-free lattice. The authors extended their earlier approach for grain size estimation, based on statistical fluctuations of X-ray intensity, to Debye rings recorded at the KISI-Kurchatov synchrotron for annealed Zr-1%Nb-(Fe,O) and Zr-1%Nb-1.2%Sn-(Fe,O) tubes. A threshold for the statistical deviation of recrystallized grains was found, and both the recrystallization degree and the grain size were derived from a single diffraction pattern. The correlation with EBSD data exceeded 0.9 for every reflection (up to 0.966 and 0.950, respectively), so zirconium alloys can be analysed on this facility without reference or deformed samples. The work was supported by the Russian Science Foundation (project 24-79-10289).
3. Hydride reorientation in Zr-1Nb spacer grid cells (Journal of Nuclear Materials)
M. G. Isaenkova, A. V. Tenishev, V. V. Mikhalchik, A. I. Nyityo, M. A. Polous, R. A. Ilyasov, M. I. Petrov, A. A. Bazhenov, O. A. Krymskaya, V. A. Fesenko. Hydride Reorientation in Zr–1Nb Spacer Grid Cells under Hoop Loading. Journal of Nuclear Materials, 2026, 157197. https://doi.org/10.1016/j.jnucmat.2026.157197
The study examined how hydrides redistribute in Zr-1Nb spacer grid cells of VVER-1200 fuel assemblies, where the dimples in contact with the fuel rod carry a local stress gradient. Hydrogen content and hydride distribution were measured by inert gas fusion (LECO), scanning electron microscopy and synchrotron X-ray diffraction, and the stress state was calculated by the finite element method. Hydrides are distributed non-uniformly both around the cell perimeter and through the wall thickness, in stamped and recrystallized cells alike. After a 3 h hold at 500 °C with an inserted rod and subsequent cooling, the fraction of radial hydrides in the dimple rose by about 50% in the outer layer and by 65–93% in the middle layer, in qualitative agreement with the calculation. The results can be used to assess spacer grid performance in operation, transportation and storage of fuel assemblies. The work was supported by the Russian Science Foundation (project 24-79-10289).
4. Laser powder bed fusion of thin-walled Zr-based metallic glass gyroids (Int. J. Adv. Manuf. Technol.)
B. S. Voloskov, N. Fedyanin, A. N. Suchkov, D. G. Firsov, E. A. Bazdnikina, I. V. Kozlov, O. N. Sevryukov, S. A. Evlashin, I. Sergeichev. Transferability of laser powder bed fusion parameters optimized for dense specimens to thin-walled Zr-based bulk metallic glass gyroids. The International Journal of Advanced Manufacturing Technology, 2026, published online 21 October 2026. https://doi.org/10.1007/s00170-026-19359-w
The authors tested whether laser powder bed fusion parameters optimized for dense Zr35Ti30Be27.5Cu7.5 specimens transfer to sheet-based gyroids with 100, 200 and 300 μm walls. The 100 μm gyroid showed poor wall continuity (Dice coefficient 0.479–0.564), while the 200 and 300 μm gyroids had better continuity (up to 0.865) but thicker walls, 0.51% porosity against 0.06% and detectable crystalline phases. Microhardness stayed close to the dense reference (555–574 HV0.3), so geometry-specific optimization is needed to keep the structure X-ray amorphous and the walls continuous. The work was supported by the Russian Science Foundation (project 25-79-10314).