Safety Case Toolkit

Throughout the lifecycle of a facility, from conception through to decommissioning, there are various key stages which require special consideration. The safety case for each stage should demonstrate the safety of that stage before it commences, and should be forward looking to subsequent stages aligned to Office for Nuclear Regulation (ONR) guidance (ONR NS-TAST-GD-051). For facilities under design or construction, the safety case at each stage should contain sufficient detail to give confidence that the safety intent will be achieved in subsequent stages.

The Safety Case Dataset identifies the key information that is used to construct the safety case and is linked to the building blocks described in the Safety Case Process Diagram.

Step 1 is the initiation Step where matters such as the scope and timescales are agreed, and ONR's knowledge of the design and the RP's safety and security cases increases. Importantly, this Step includes the RP identifying any immediate gaps in meeting regulatory expectations and proposing how these will be subsequently resolved.

Step 2 is the fundamental assessment of the generic safety and security cases, to identify any potential 'showstoppers' that may preclude deployment of the design.

The Design Assurance (DA) process is a formal, systematic process that augments the design effort and increases the probability of product design conformance to requirements and project needs.