Week 1: Main Steam/Main Turbine Flashcards
What loads are supplied by Main Steam?
Aux steam reboiler
HP FW Heaters
MFP Turbines (Low Power)
Steam Dumps
Condenser Sparging
Gland Seal Steam Supply
Which Steam Generators feed the AFW turbine driven pumps?
B and C
What is the function of the SG MSIVs?
To isolate the associated SG from the rest of the main steam system in an emergency.
What is the function of the MSIV bypass valve?
To permit warming of downstream steamlines and to equalize steam pressure across an MSIV to permit it to open.
What is the function of the SG PORVs?
To relieve pressure prior to the actuation of the MSSVs; opens at 1125 psig.
Can also remove heat from the RCS when the plant is starting up/shutting down, or when the main condenser is OOS.
What is the function of the SG safeties?
The 5 MSSVs prevent steam system overpressure and prevent Tavg from rising beyond the Tech Spec Safety limits at low powers.
The first valve opens at 1185 psig, with subsequent valves opening every +12 psig.
What is the function of the Steam Dumps?
To provide an artificial steam load to moderate the reactor power transient following a sudden reduction in turbine steam demand; can accommodate up to 40% RTP.
What is the function of the HP turbine?
To accept the high pressure steam from the SG common header; consists of 1 turbine.
Source of extraction steam for the 1st stage MSR heaters, as well as the HP FW heaters.
What is the function of the Moisture Separator Reheaters?
To reduce the water content in the steam exhausted from the HP turbine in order to avoid damage to the LP turbines.
1st stage - Heated by HP turbine extraction steam
2nd stage - Heated by Main Steam extraction steam
Provides extraction steam for the MFW pumps at high powers.
What is the function of the LP turbines?
To accept dried and reheated steam from the MSRs.
A source of extraction steam for the LP FW heaters.
