In order to obtain license renewal for RSG-GAS operation expired in 2020, an evaluation on periodic safety review (PSR) should be performed as required by BAPETEN regulation. This PSR had been done from 2005 to 2015. The objectives of the qualification review is to ensure that the critical structure, system, and component (SSC) for safety fulfils the requirements. SSC, which is important to safety, is reviewed in term of its environment, service frequency, aging mechanism, aging mitigation, and aging degradation detection. The results of this detection are evaluated to achieve sustainable and safe operation and to identify SSC replacement and repair before a failure occurs. From the evaluation results, it can be concluded that SSC qualification during the period of 2005 – 2015 still fulfils the requirements so that safe and sustainable operation of RSG-GAS is assured.