Nuclear power plant is a huge system with multidisciplinary technology. So, R & D prioritization is a not a simple task and the relative importance of each prioritization criterion is not well established. This study built a technology classification chart for nuclear power plant operation and maintenace, established the relative importance of prioritization criteria and assigned the relative importance of each technology at each level. Analytical Hierarchy Process was used for the prioritization and the result was validated with Consistency Index and outcomes of fields interview.