scope:

This Safety Guide presents recommendations on applying a graded approach without compromising safety.

The application of a graded approach to all of the important activities4throughout the lifetime of a research reactor is discussed. These activities are identified in sections 3-8 of Ref. [1]. A major aspect of the design activity, as described in Section 6 of this Safety Guide, involves the grading of specific requirements for design of structures, systems and components (SSCs) for particular reactor types, so that the safety objectives set out in Para. 2.2 of Ref. [1] are achieved. Recommendations on the application of grading to reactor hardware and equipment (SSCs), as opposed to activities in general, are also provided in Section 6.

In this Safety Guide, it is considered that all relevant safety requirements have to be complied with in applications of a graded approach. The graded approach should be used to determine the appropriate manner to comply with a requirement; it is not used to provide relief from meeting the requirement. To eliminate a requirement for the purposes of identifying all relevant safety requirements, a waiving5 process, as suggested in Para 1.10 of Ref. [1], can be used.