The safety assessment for facility industry is now being periodically performed in Korea. For the purpose of scientific safety management, QRA(Quantitative Risk Assessment) is also being performed, and reliability data of the facilities is essential to perform the assessment. The necessary reliability data for QRA have been generally announced the values in other process industries, which results in the drop of risk reliability. The most appropriate method is to perform a direct reliability analysis towards the facilities undergoing safety assessment. In this study, the distinction between homogeneous sample estimation and multi-sample estimation of reliability data clarify using 2-Bayes theory.