NSSS control and indication instrumentation is not part of the safety system instrumentation; however, NSSS Instrumentation is required for day-to-day operation of the plant and is modeled in the safety analysis so that control systems can be counted on to perform in a safe operating envelope. These control systems are also designed to handle anticipated transients in such a way as to mitigate severe consequences and return the plant to normal operating conditions. If the NSSS control systems fail to keep the reactor within its normal operating envelope, the safety system takes over and either shuts the reactor down and/or actuates safety features to protect the reactor.