Structures, systems and components for abnormal operating conditions

STRUCTURES, SYSTEMS AND COMPONENTS FOR ABNORMAL OPERATING CONDITIONS 

Structures, systems and components important to safety vhich are installed as redundant items, or are called upon when normal operating conditions are threatened or lost, are normally kept in standby or off-line states. Examples of such SSCs are reactor containment vessels, emergency electric power sources, isolation valves and safety valves. Some of these SSCs cannot be monitored in situ for their operating reliability. Testing and surveillance for the actual conditions under which they are expected to operate, and which are generally difficult or impossible to reproduce, are usually undertaken under simulated conditions. These simulated conditions should be carefully planned, and the results should be interpreted prudently. 

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