This standard applies to the design of instrumentation to monitor and display required post accident conditions within the nuclear power generating station. Instrumentation addressed by this document includes that which enables the operator to: (1) identify the accident to the degree necessary for him to perform his role; (2) assess whether or not safety systems are accomplishing the required safety functions (for example, cooling the core, controlling containment pressure, etc); (3) determine when conditions exist that require specified manual actions and monitor the results of those actions; and (4) follow the course of the accident to determine whether or not conditions are evolving within prescribed limits. This document does not include criteria for instrumentation used only to monitor status, maintenance, or degradation of individual items of safety system equipment during the post accident period