Considerations of Material Selection for Control Rod Drive Mechanism of Reaktor Daya Eksperimental

Abstract

Several materials were considered for the Control Rod Drive Mechanism (CDRM) of Reaktor Daya Eksperimental, which is categorized as High Temperatures Gas-Cooled Reactors (HGTR). Nickel base alloys were found to be more superior compared to other types of materials for the CDRM. This paper reviews the mechanical properties and corrosion behaviour of Ni-base alloys at high temperature. The effect of neutron bombardment on the materials was also reviewed as an important condition. It is likely the that Inconel 625 and Inconel 686 are more suitable for the use of CDRM of HGTR, compared to another alloy, Incoloy 800H. The mechanical properties of Inconel 625 and Inconel 686 exposed at high temperatures are excellent, similar results found on the corrosion resistance. The neutron irradiation caused the embrittlement on Inconel 625 and Incoloy 800H. The yield and ultimate strength decreased insignificantly, ranging from 13-46%. Comparing with other mechanical properties, such as total elongation, it suffered much further reduction, ranging from 60-62%. This result implies that the materials underwent embrittlement.