In complex process systems, the importance of human performance related problems has been well recognized through many significant events. As a result, HRA has been emphasized as one of the main streams for unraveling human performance related problems. A lack of prerequisite information, however, has frequently degraded the quality of HRA results. For this reason, OPERA database that can provide operators' performance data obtained under simulated emergencies has been developed by KAERI. In this study, typical operators' performance data that are available from OPERA database are briefly explained. After that, in order to ensure the appropriateness of OPERA database, operators' performance data obtained from OPERA database are compared with those from another simulation and real events. As a result, it is believed that operators' performance data of OPERA database are fairly comparable to those of simulations and real events. Therefore it is expected that OPERA database can be used as a serviceable data source for scrutinizing human performance related problems including HRA.