Easy Approach to Requirements Syntax in Nuclear Power Plant Safety Design

We describe our experience of Easy Approach to Requirements Syntax (EARS) requirements templates in the safety design of a new build nuclear power plant (NPP) project from the perspective of the customer stakeholder, which is external to the design organization but however bears ultimate responsibility for the safety of the design. The plant supplier chose EARS as the guideline for writing requirements in the safety engineering of the NPP. We found that the templates promoted uniformity and understandability of requirements, and as external stakeholder, resulting requirements were understandable without any specific EARS training. We observed that EARS was adopted in a very limited format. For high level requirements, EARS conformity was not strictly observed due to limitations of the template in the requirements of the domain. Still the resulting requirements expression is perceived to be better than the use of no template. We introduce a concept to provide a more abstract interpretation of the elements of the EARS templates so requirements targeted at higher level design entities can be expressed in a consistent way.