Passive safety refers to safety system components, whereas inherent safety refers to control system process regardless of the presence or absence of safety specific subsystems.ДЄs an example of a safety system with 'passively safe' components, let us consider the containment of a nuclear reactor. Sometimes a system combines both features. Safety systems are used to maintain control of the plant if it goes outside normal conditions in case of anticipated operational occurrences or accidents, while the control systems are used to operate the plant under normal conditions.

It is very important to understand that there are no 'passively safe' reactors or 'passively safe' systems, only 'passively safe' components of safety systems exist. Reactor vendors like to call their new generation reactors 'passively safe' but this term is sometimes confused with 'inherently safe' in the public perception. They can be said to be 'relatively safe' compared to previous designs. This said, modern reactor designs have focused on increasing the amount of passive safety, and thus most passively-safe designs incorporate both active and passive safety systems, making them substantially safer than older installations. Whether a reactor employing passive safety systems is to be considered safe or dangerous will depend on the criteria used to evaluate the safety level. Terming a reactor 'passively safe' is more a description of the strategy used in maintaining a degree of safety, than it is a description of the level of safety. 3 Examples of reactors using passive safety features.2 Examples of passive safety in operation.

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