Safety Case Toolkit

A safety case is rarely a single document; it consists of the entirety of the body of evidence presented that demonstrates that the hazard presented by the Nuclear Power Plant (NPP) is adequately controlled and mitigated such that the risk to workers and the public is As Low As Reasonably Practicable (ALARP).

Model Based System Engineering (MBSE) is one of a number of applications that could be used to capture an Electronic Safety Case, or to map the key processes and information that are used to develop the safety case. Though the definition and purpose of MBSE is discussed in this document, the application of MBSE in the nuclear sector has been considered within a separate research task.

There is a requirement to explore ways of developing and presenting Nuclear Power Plant (NPP) safety cases more efficiently if targeted cost savings are to be met. The capabilities of current safety case tools and methods are being challenged by many factors, including the complexity of modern NPPs, regulatory requirements and advances in industry guidance, including fault and hazard studies. Many of these challenges relate to the ability to access, link, and update the information that forms the basis of the safety case.

In order to build and operate a Nuclear Power Plant (NPP) in the UK, the operator is required to obtain licences and permissions from a number of different bodies. These bodies include planning authorities, environmental regulators, and, importantly in the context of a nuclear safety case, the Office for Nuclear Regulation (ONR) which is responsible for granting a nuclear site licence. This is a legal document, issued for the full life cycle of the facility.