Determination of radiation shielding characteristics of some essential nickel-based alloys that can be used in nuclear energy applications

In this thesis, it was focused on discovering new alternative materials that provide optimal conditions to be integrated into nuclear energy applications due to the insufficient properties of conventional radiation shielding materials. In this context, radiation shielding performances and characteristics properties of five different Ni-based alloys named Evanohm, Alloy 825, Haynes 230, Monel K-500 and Monel 400 were investigated. To determine the radiation shielding performances of these alloys, firstly, photon-matter interaction parameters (MAC, LAC, HVL, MFP, ACS, ECS, Zeff, Neff, σeff ve RPE) were experimentally determined using the EDXRF technique in the energy range of 30-1333 keV. At the same time, these parameters were also calculated theoretically using the Phy-X/PSD software to determine the experimental errors. Secondly, Rinc/toplam, Zeq, EBF and EABF parameters giving information about the photon scattering characteristics of the materials were calculated in the wide energy range of 0.015-15 MeV. The radiation shielding capabilities of the studied alloys were compared with steel-magnetite (SM) concrete and Cupero-Nickel (CN) alloy. Finally, based on the results obtained, the physical, chemical, mechanical, thermal and radiation shielding properties of the alloys were evaluated together and the most suitable alloy that could be used in nuclear energy applications was selected. As a result of the research, the radiation shielding performance orders of the examined materials were determined as Haynes 230>CN>Monel 400>Monel K-500>Evanohm>Alloy 825>SM. Moreover, it was determined that Haynes 230 alloy showed approximately 40% more shielding performance than other alloys. In addition to this result, it was determined that Haynes 230 alloy has better elongation at break (%<50), better tensile strength (860 MPa), better elastic modulus (211 GPa), lower thermal conductivity (8.9 W.m-1.K-1 at 23 0C), lower specific heat (397 J.K-1.kg-1 at 23 0C), greater density (8.97 g/cm3), low thermal expansion coefficient (13x10-6 K-1 at 20-150 0C) and high melting point (~1350 0C) than other investigated Ni-based alloys. Thus, it was observed that the Haynes 230 alloy meets the optimal properties that can be used in nuclear applications with these superior characteristics. Consequently, it has been concluded that this alloy can be used as a building material in reactor design in nuclear applications and as a shielding material in nuclear power plants and other ionizing radiation applications.