Plant operating conditions
Pressurized water reactors

Power plants are normally operated in automatic power control mode. Apart from a permanent monitoring role, particularly in the event of an alarm, operators intervene mainly during start-up and shutdown operations, and on a number of large-amplitude load variations (to adjust boron concentration in the primary circuit).

In the event of an incident, the control and protection systems automatically return the reactor to a safe state, and operators are given a period of time, which varies according to the stage, before they have to perform the manual actions ultimately required to safeguard the plant. This time has increased from 10 to 30 minutes between the first stage (900 MW) and the current stage (EPR), thanks to advances in the design...