Effect of Ni Addition on the Density, Microstructure, Hardness, and Phase Stability of U–7Mo–xNi Alloys
DOI:
https://doi.org/10.55981/urania.2026.16013Keywords:
density, microstructure, hardness, phase, U-Mo-xNi alloyAbstract
The Reduced Enrichment Research and Test Reactor (RERTR) program required a transition from high enriched uranium (HEU) to low enriched uranium (LEU). The most promising nuclear fuel with LEU is uranium-molybdenum (U-Mo). U-Mo has high density and can act as g-U stabilizer, but under irradiation test, showed undesirable interaction with aluminum (Al) matrix. To stabilizing g and minimize interaction with Al, Ni was added to U-7Mo. The study began with fabrication of U-7Mo-xNi alloy using an electric arc melting furnace under an argon atmosphere. The resulting U-7Mo-xNi were characterize through microstructural observation using optical microscope, density measurement using automatic gas pycnometer, hardness testing using Vickers, and phase identification using x-ray diffraction (XRD) then compared to U-7Mo. The results show that U-7Mo-xNi has lower density than U-7Mo, with 17.42 for U-7Mo, 16.77 g/cm3 for U-7Mo-1Ni, 16.45 g/cm3 for U-7Mo-2Ni and 16.42 g/cm3 for U-7Mo-3Ni. The average grain size also shows a decrease from 20.97 µm to 14.41 µm, which leads to an increase in hardness based on Hall-Petch relations. The results of hardness test show the higher value than U-7Mo with value 240.4 HV, 313.87 HV, 340.51 HV and 357.47 HV for U-7Mo-xNi as Ni composition in order. For XRD analysis, peaks detected at 2θ angle of 37.0°, 53.6° and 66.5° same as U-7Mo peaks and identified as g-U phase, but in U-7Mo-xNi has a minor peak at 2θ angle of 40.8° identified as Mo. The addition of Ni to U-7Mo improve the hardness of the alloy and the g-U phase still be maintained. The dendritic structure and minor peaks in U-7Mo-xNi indicate the need for further homogenization and characterization.
References
[1] M. H. Alhasa, Masrukan, and J. Setiawan, “Effect of Mo Content on the -UMo Phase, Thermal Conductivity and Density Of UMo Alloy,” Tangerang Selatan, Mar. 2017. [Online]. Available: http://ganendra.batan.go.id
[2] S. Pinem and T. M. Sembiring, “Accuracy of Batan-3DIFF and MCNP6 codes for thermal neutron flux distribution at the irradiation position of RSG-GAS reactor,” International Journal of Nuclear Energy Science and Technology, vol. 13, no. 4, pp. 295–312, 2019.
[3] J. C. Sihotang et al., “Study of Fission Gas Bubbles and Interaction Layer on Irradiated U3Si2-Al Density off 4.8 gU/cm3,” Urania: Jurnal Ilmiah Daur Bahan Bakar Nuklir, vol. 28, no. 2, p. 69, Jun. 2022, doi: 10.17146/urania.2022.28.2.6670.
[4] S. Supardjo, A. Kadarjono, J. Setiawan, and G. K. Suryaman, “Komposisi, Struktur dan Densitas Paduan U-7Mo-XSi,” Urania: Jurnal Ilmiah Daur Bahan Bakar Nuklir, vol. 27, no. 2, p. 57, Jun. 2021, doi: 10.17146/urania.2021.27.2.6386.
[5] K. Sun, L. wen Hu, T. Newton, E. Wilson, and A. Olson, “Estimate of radiation release from MIT reactor with un-finned LEU core during Maximum Hypothetical Accident,” Progress in Nuclear Energy, vol. 97, pp. 231–244, May 2017, doi: 10.1016/j.pnucene.2017.01.013.
[6] Supardjo, “Karakterisasi Paduan UxSiy pada Daerah Komposisi antara 6,62 s/d 7,63 %Si,” 1993.
[7] S. Octadamailah et al., “Analysis of Density, Phase, And Microstructure In U–Mo Alloys” Urania: Jurnal Ilmiah Daur Bahan Bakar Nuklir, vol. 31, no. 1, pp. 49–56, May 2025, doi: 10.55981/urania.2025.10793.
[8] W. M. Haynes, D. R. Lide, and T. J. Bruno, CRC Handbook of Chemistry and Physics 97th Edition. CRC Press, 2017.
[9] IAEA, “Material Properties of Unirradiated Uranium-Molybdenum (U-Mo) Fuel for Research Reactors,” 2020.
[10] N. T. H. Kim-Ngan, I. Tkach, S. Mašsková, L. Havela, A. Warren, and T. Scott, “Cubic γ-phase U-Mo alloys synthesized by splat-cooling,” Advances in Natural Sciences: Nanoscience and Nanotechnology, vol. 4, no. 3, 2013, doi: 10.1088/2043-6262/4/3/035006.
[11] M. J. Alarcón, M. Barrera, J. Hernández, J. Lisboa, L. Olivares, and A. Navarrete, “Methodology for ultrasonic inspection of dispersion type U–Mo fuel plates,” Progress in Nuclear Energy, vol. 130, Dec. 2020, doi: 10.1016/j.pnucene.2020.103572.
[12] A. Ewh, E. Perez, D. D. Keiser, and Y. H. Sohn, “Microstructural characterization of U-Nb-Zr, U-Mo-Nb, and U-Mo-Ti alloys via electron microscopy,” J. Phase Equilibria Diffus., vol. 31, no. 3, pp. 216–222, Jun. 2010, doi: 10.1007/s11669-009-9645-4.
[13] F. A. Furqan et al., “Neutronic analysis of U-7Mo-xTi/Al fuel elements as replacement candidates for Indonesia’s RSG-GAS research reactor fuel: Enrichment optimisation, burnup behaviour, and temperature coefficients,” Ann. Nucl. Energy, vol. 229, p. 112091, May 2026, doi: 10.1016/j.anucene.2025.112091.
[14] J. M. Park et al., “Effect of Si and Zr on the interdiffusion of U-Mo alloy and Al,” Journal of Nuclear Materials, vol. 374, no. 3, pp. 422–430, Mar. 2008, doi: 10.1016/j.jnucmat.2007.09.059.
[15] S. Jana, L. Sweet, D. Neal, A. Schemer-Kohrn, C. Lavender, and V. Joshi, “The role of ternary alloying elements in eutectoid transformation of U10Mo alloy part I. Microstructure evolution during arc melting and subsequent homogenization annealing in U9.8Mo0.2X alloy (X = Cr, Ni, Co),” Journal of Nuclear Materials, vol. 509, pp. 318–329, Oct. 2018, doi: 10.1016/j.jnucmat.2018.06.024.
[16] Y. Wang et al., “Effect of minor Ni addition on the microstructure, mechanical properties and corrosion behavior of Mg-2Gd alloy,” Journal of Materials Research and Technology, vol. 20, pp. 3735–3749, Sep. 2022, doi: 10.1016/j.jmrt.2022.08.051.
[17] G. K. Suryaman, M. Waziz Wildan, and Y. Dwi Agus Susanto, “Production Of Uranium−Molybdenum Alloy as a Candidate for Nuclear Research Reactor Fuel,” Naskah disetujui, pp. 12–12, 2018.
[18] X. Li, W. Gao, and Q. Jiang, “Understanding the intrinsic framework of the Hall-Petch relationship of metals from the view of the electronic-structure level,” Acta Mater., vol. 292, Jun. 2025, doi: 10.1016/j.actamat.2025.121071.
[19] E. Febriyanti, D. Priadi, and R. Riastuti, “Pengaruh Thermomechanical Controlled Processed (TMCP) Terhadap Penghalusan Butir Dan Sifat Mekanik Paduan Cu-Zn 70/30,” Dec. 2015. [Online]. Available: www.ejurnalmaterialmetalurgi.com
[20] H. Wang, B. Li, X. Xin, W. Wang, and K. Wang, “Preparation of fine-grained/ultrafine-grained Nb521 alloy with superior mechanical property by friction stir processing,” Journal of Materials Research and Technology, vol. 33, pp. 1048–1063, 2024, doi: https://doi.org/10.1016/j.jmrt.2024.09.120.
[21] D. H. Iftikhoor, “Pengaruh Penambahan Nikel Pada Paduan U-7Mo Sebagai Kandidat Bahan Bakar Nuklir Tipe Pelat Untuk Reaktor Serba Guna – G.A Siwabessy,” Skripsi, Universitas Padjadjaran, Bandung, Indonesia 2026.
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2026 Diinar Hasnaa' Iftikhoor, Ratih Langenati, Ganisa Kurniati Suryaman, Saga Octadamailah, Muhammad Alfarisie, Juan Carlos Sihotang, Slamet Pribadi, Mujinem, Brigitta Verren Kasih Pramesti, Nowo Riveli
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
