Implementation of in-service inspection program for HANARO

HANARO, a 30 MW multi-purpose research reactor in Korea has been successfully in operation for 6 years since its initial criticality in February 1995. It is mainly used for the research areas including nuclear fuel and material irradiation tests, radioisotope production, neutron beam application, neutron activation analysis and neutron transmutation doping. HANARO was designed to perform for at least 20 years under full power operating condition. It is expected that the actual reactor lifetime will be much more than the design lifetime, due to a safety reassessment based on realistic data, preventive maintenance and appropriate in-service inspections (ISI). Since ageing may affect the overall safety of the reactor facility, it is needed to detect and evaluate the effects on aged components and systems related to safety. During the lifetime of the reactor, structures, systems and components are subjected to environmental conditions of stress, temperature and irradiation that may lead to changes in the material properties and could result in unexpected failures. Evidence of ageing problems appears progressively. A rigorous inspection and visual examination based on a periodic ISI program should be established. It is desirable that the ageing surveillance activities is scheduled as early as possible and continued throughout the operating life of the reactor. An inspection plan for safety related structures, systems and components subjected to the ageing conditions is requested by the regulatory body to assess the safety status of reactor facility. A long-term ISI program for HANARO has been established for safety-related systems and components in the context of the overall reactor ageing management. The objective of this paper is to describe the ISI program and the result of the visual inspection as the first ISI. (orig.)