Flashcards in SBCS: Steam Bypass Control System Deck (77)
What is SBCS designed to do?
Prevent unnecessary reactor trips and opening of Pressurizer and SG Safeties.
How much of a load rejection can SBCS handle without a RPCB?
What valves make up Group X in SBCS?
1001, 1004, 1003, 1006
When does Group X Quick Open?
On a Reactor Trip if Tc > 575F
A step change of 15%-20%
What valves make up Group Y in SBCS?
1002, 1005, 1007, 1008
When does Group Y Quick Open?
A step change of 45%-50%
How many SBCS valves does each condenser shell have?
A - 3
B - 2
C - 1
Atmosphere - 2
Why the uneven number of SBCS valves to the condenser shells?
To ensure equal shell loading
What is the only position the System Mode Selector Switch can be in where SBCS will work?
What must be done prior to changing the TLI Selection in the SBCS?
You have to be in EMERGENCY OFF or you have to be in MANUAL on the Master Controller.
When changing the position of the System Mode Selector Switch on the SBCS, what must be done?
You have to be in EMERGENCY OFF or a QO may be generated.
What is the black needle on the SBCS Master Controller?
The local setpoint generated with the thumbwheel
What is the black and white needle on the SBCS Master Controller?
The remote setpoint
What is the Modulation signal based on when in AUTO on the SBCS Master Controller?
error between steam header pressure and the pressure setpoint
When in MANUAL on the SBCS Master Controller, how is the output controlled?
Via the slide switch
What must be done before going to LOCAL on the SBCS Master Controller?
You have to go to Manual or you'll get a QO.
If power is lost to the SBCS Master Controller for < 2 seconds, in what mode will it return?
If power is lost to the SBCS Master Controller for > 2 seconds, in what mode will it return?
SBCS shifts to EMERGENCY OFF
What SBCS function is not available while in REMOTE/AUTO on the Master Controller?
To what does the output on the SBCS Master Controller go when a Quick Open occurs? Why?
So that transfer to modulation occurs smoothly
What do you want to do before going to LOCAL/AUTO on the SBCS Master Controller?
Input manual permissives to prevent popping SBC valves.
When in AUTO, from where do the Individual Controllers get their demand signal?
From the SBCS Master Controller
What are the implications of going to MANUAL on an Individual Controller in the SBCS?
It reduces your availability
What indicates actual valve position on an Individual Controller in the SBCS?
The red needle
When an Individual Valve in the SBCS is placed in OFF on the switch, what happens?
The valve will not open under any circumstances
When an Individual Valve in the SBCS is placed in AUTO on the switch, what happens?
The valve will get its permissive signal from the permissive circuit
When an Individual Valve in the SBCS is placed in MANUAL on the switch, what happens?
The permissive signal is manually input and energizes the permissive solenoid. White light comes in.
How many Individual Valves in SBCS can be given a manual permissive at a time?
What provides the inputs to the Modulation Circuit for SBCS?
Steam Pressure (PT-1024)
Steam Flow (FT-1011/1012)
Pzr Pressure (PT-100X)