Reactor protection system

A reactor protection system is a set of nuclear safety and security components in a nuclear power plant designed to safely shut down the reactor and prevent the release of radioactive materials. The system can "trip" automatically, or it can be tripped by the operators. Trips occur when the parameters meet or exceed the limit setpoint. A trip of the RPS results in full insertion of all control rods and shutdown of the reactor.

Pressurized water reactors

Some of the measured parameters for US pressurized water plants would include:

"High power", auctioneered between high nuclear power and high differential temperature between the inlet and outlet of the reactor vessel.
"High startup rate" at low power levels.
"High pressurizer pressure"
"Low reactor coolant flow"
"Thermal margin / low pressure"
"High containment pressure"
"Low steam generator level"
"Low steam generator pressure"
"Loss of load"

Each parameter is measured by independent channels such that actuation of any two channels would result in an automatic SCRAM or reactor shutdown. The system also allows manual actuation by the operator.