A process for establishing an Integrated Management System (IMS) for operation and maintenance of the ETRR-2 reactor is initiated. Development and application of the IMS consider the usage of a graded approach in order to commensurate the resources devoted to management system with the importance of an item/activity and the magnitude of the risks. Literatures have introduced different methods for the concept of graded approach which is very important in applying the management, safety and technical requirements. This paper provides an additional example for the methodology of applying such approach. It suggests a grading methodology and determines the considerations that need to be taken into account in grading the application of IMS requirements. The paper introduces a proposal for classification of items or activities in the ETRR-2 into four grades. Then gives a grading example of specific controls for maintenance of structures, systems and components (SSCs) in the plant and explains the management requirements appropriate for each grade. Finally, the approach is explained briefly using an application practice on the Standby Power Supply system of the plant as a case study.