Abstract The oldest commercial reactor in South Korea, Kori Unit 1 Nuclear Power Plant (NPP), will be permanently shut down starting in 2017. Since decommissioning of NPPs will generate a huge amount of radioactive metallic waste, proper treatment for decommissioning wastes is one of the key factors to decommission a plant successfully. Many studies have been conducted and experience accumulated for waste minimization and the reduction of disposal volume. Melting technology is one of the proven technologies for effectively managing the metallic waste and has been adopted by many countries. However, a licensed melting facility to dispose of metallic wastes from the NPP decommissioning has not been implemented in Korea. The purpose of this study is to establish a management plan for metallic waste and to evaluate the preliminary doses according to the acceptance criteria and operations at the facility. Based on the available research papers and empirical data from domestic and international experience, the operational concept and the melting technology principle were established and its dose and volume reduction effects were evaluated. The concept of operating a melting plant is to finally free release the ingots after melting or free release after a planned storage period. Based on this concept, the radioactive concentration of the scrap metal which can be treated was derived, demonstrating that melting can be applied to low level and very low level wastes above the clearance level. The RESRAD-RECYCLE computer code was used to assess worker doses and was rated within the regulatory limits in most scenarios, except for slag workers. Factors affecting the dose, such as methods of radiation protection, operating method and working time, will be important factors in establishing the melting facility and the radiological limits should also be determined accordingly.