Rod Control Flashcards
State functions of the Rod Control System
Moves control rods in responds to signals from the Reactor Control Unit (RCU)
Maintians RCS Tave within +- 1.5F of programmed value when >15% turbine power (C-5) for the following:
+- 10% step load change
+- 5%/ minute ramp load changes
+- 50% step decrease with steam dumps
What happens when both bypass breakers are racked in and closed
Both breakers open tripping the reactor.
This is independent of RPS
State the inputs for the Rod Control Unit
Tref - Tave NI power vs actual turbine power - PMM Total error = Tref - Tave + PMM Tave varies with RX power (557 - 589.1) Polarity of error determines direction magnitude of error determines speed
State the speed of rods in manual
Shutdown: 64
Control: 48
State speed of rods in Auto
1.5F - 3F: 8 steps/min
>3F - 5F: 32 steps/min/F change
>5F: 72 Steps/min
State C-1
20% IR equiv. current (1 of 2)
Blocks manual and auto rod withdrawal
resets at 10% (2 of 2)
State C-2
103% power range (1 of 4)
Blocks manual and auto rod withdrawal
A channel can be bypasses (coincidence becomes 1 of 3) using Rod Stop Bypass Switches
resets at 101% (4 of 4)
State C-5
15% Turbine power (1 of 1)
Fed from PT-505
enables auto rod withdrawal above 15% turbine power
resets at 13%
State C-11
Stops AUTO rod withdrawal for Control Bank D at 223 Steps
State Rod Control response when PR channel Fails High
PR>Turbine power
PMM error inserts rods
Actual Tave decreases
Tref>Tave calls for rod withdrawal
C-2 high flux (103% power) stops rod withdrawal
Need to place rods in MAN to stop insertion
State Rod Control response when PR channel Fails Low
No effect NI input to PMM s auctioneered high
State Rod Control response when Loop Tave fails low
AveTave < Tref
Rods will withdraw if: Control bank D is below C-11 block of 223 or C-2 of 103%
State Rod Control response when PT-505 fails high
Turbine power > auctioneered high PR
PMM error withdrawals rods if: Bank D is below 233 (C-11) and Power remains below C-2 (103%)
State Rod Control response when PT-505 fails low
Auctioneered high PR > Turbine power PMM error inserts rods Tref drops to no load value of 557 Rods inserts at 72 steps/min need to place rods in manual to stop insertion
State Rod Insertion Limit (RIL) basis
Ensures adequate SDM
Ensures core power distribution limits are maintained
Ensures rod ejection accident remains within design analysis
State P/A converter relationship with regards to the RIL
Provides VAS alarm RIL low when within 10 steps
Provides VAS alarm RIL low-low when at or below RIL
Calculates the RIL based on Delta-T 0-60F (auctioneered high Delta-T) and 0-100% power
State T.S. 3.1.1.1 (Boration Control) LCO and Action
The Shutdown margin for 4 loop operation shall be >= the limit specified in the COLR
MODE: 1-4
Immediately initiate and continue boration at >=30GPM until the SDM is restored
State T.S. 3.1.1.2 (Boration Control - Shutdown) LCO and Action
The SDM shall be >= the limit specified in the COLR. Additionally, the RCS Boron concentration shall be >= the concentration of the COLR when the RCS loops are in a drained condition
MODE: 5
Immediately initiate and continue Boration at >= 30GPM until the SDM is restored
State T.S. 3.1.3.1 (Group Height) LCO and Action
All control Rods shall be operable and positioned within +/- 12 steps (DRPI) of their groups step counter demand positions
MODE: 1 and 2
Verify SHUTDOWN MARGIN within 1hr and be in HOT STANDBY within 6 hours
State T.S. 3.1.3.5 (Moveable Control assemblies) LCO and Action
All shut down rods shall be fully withdrawn as specified in the COLR
MODE: 1 and 2
With a maximum of 1 shutdown rod not fully withdrawn, within 1HR either:
- Fully withdraw the Rod or
- Declare the Rod inoperable and apply 3.1.3.1
State the function of the slave cycler and where it sends signals to
Provides the control signals, current orders, to gate its respective power cabinets SCR's Provides demand signals to: - MPCS - MCB step Counters - P/A converter
Discuss Logic cabinet Urgent failure
Stops all rod motion
Protects against dropping a rod
Alarm must be manually reset
Discuss Power Cabinet Urgent failure
Stops rod motion for that cabinet only
Protects against dropping a rod
Rods in the unaffected banks may be moved in individual bank mode
Discuss components affected by Rod Control Start up switch
Resets: Master cycler counter slave cycler counters Bank overlap counter P/A Counter All internal memory and alarm circuits
State the problem with pushing Rod Control Start up switch at power
Group step counters goto zero causing demand/DRPI rod deviattion alarms
Bank overlap units selects Bank A for Motion
RIL alarm on all banks
