e-learning view The Manual here
DEFENCE IN DEPTH
Defence in depth: reactors

INITIATOR

 

Coming back to INES and events, the picture basically shows two types of events that can occur.

Some failures can occur in the front end, leading to an initiating event.

Some failures can occur in safety systems or accident management systems. These lead to no immediate effects, but leave the reactor unprotected against an initiating event.

Both of these types of events are usually reported and communicated to the public, so we need to rate them on INES.