Mission time

Each plant system has a mission time. As a result the systems are evaluated and designed to their mission time. {Mission time may vary by function for a particular system.}

If mission time was a Car then it would be the time it takes to drive you to work and back.

Unfortunatly there is no single mission time for any system. It depends on who is asking the question and under which scenerio. Probabalistic Risk Assesment deals with many disaster scenerios. Each requires various plant components to function for different amounts of times.

One accident model is the Design Basis Accident scenerio. Enviromental Qualifications deals with this set disaster scenerios and defined mission times