Week 3: Reactor Protection System Flashcards
What is the overall purpose of the Reactor Protection System?
To supply reactor and component trip signals
To initiate ESFAS signals
What are the components of the RPS?
Process Control Instrumentation, including setpoint bistables
Solid State Protection System
Describe the function of the Process Control Instrumentation.
An parameter transmitter (Pressure, Temperature, etc) feeds a set of electronics, which then feeds a bistable related to the relevant trip function. The bistable then compares the incoming signal to the reactor trip setpoint to determine if a trip signal should be generated. These signals (trip/no trip) are fed to 2 trains of RPS in parallel.
What is the normal status of the Process Control Instrumentation? After the trip criteria has been met? Why?
Normally, the bistables are energized, indicating that a trip signal does not exist to the SSPS. When the trip criteria has been met for that channel, the bistable deenergizes. The system is set up this way to ensure that if the system loses power it will fail safe, i.e. trip the reactor.
Describe how the SSPS processes incoming signals from the upstream instrumentation.
The SSPS makes the logic decision to trip, i.e. it examines the number of incoming trip signals from the process control channels and compares them against the coincidence logic of the specific trip in question.
How does the SSPS trip the rods once the coincidence logic has been met?
There are 2 trains of SSPS, each in control of a reactor trip breaker that are in series with each other. When either train reaches the decision to trip, its respective breaker will open, deenergizing the CRDMs and dropping the rods into the core.
What is the purpose and configuration of the reactor trip bypass breakers?
There are 2 bypass breakers in series with each other and parallel to the Rx trip breakers. This allows for one train of RPS to be taken out of service for testing while at power without forcing a reactor trip.
What are the system requirements mandated by the Single Failure Criteria?
Redundancy
Independence
Diversification
Fail Safe
Testability
What is the purpose of the AMSAC system?
The AMSAC system consists of a completely separate set of equipment from the RPS, from the sensor output to final actuation device, that will trip the turbine and start AFW in the event of a failure of the RPS to trip the reactor.
