Primary Coolant Pumps Flashcards
LCO 3.4.1 “PCS pressure, temperature, and flow DNB limits” requirement
PCS DNB parameters for PZR pressure, cold leg temperature, and PCS total flow rate shall be within limits specified in the COLR
LCO 3.4.1 “PCS pressure, temperature, and flow DNB limits” applicability
Mode 1
LCO 3.4.4 “PCS Loops - Modes 1 and 2” requirement
2 PCS loops shall be operable and in operation
LCO 3.4.4 “PCS Loops - Modes 1 and 2” applicability
Modes 1-2
LCO 3.4.5 “PCS Loops - Mode 3” requirement
2 PCS loops shall be operable and one PCS loop shall be in operation
LCO 3.4.5 “PCS Loops - Mode 3” applicability
Mode 3
LCO 3.4.5 “PCS Loops - Mode 3” notes/exceptions
- All PCPs may not be in operation for <= 1 hr per 8 hr period, provided no operations arepermitted that would cause reduction f PCS boron concentration, and core outlet temperature is maintained at least 10 F below saturation temperature.
- Forced circulation (starting the first PCP) shall not be initiated unless PCS cold leg temperature > 430 F, S/G secondary temperature is <= reactor inlet temperature (Tcold), S/G secondary temperature is < 100 F above Tcold and SDC is isolated from the PCS and PCS heatup/cooldown rate is <= 10 F/hr, or S/G secondary temperature is < 100 F above Tcold and SDC is isolated from the PCS and PZR level is <= 57%
LCO 3.4.5 “PCS Loops - Mode 3” required actions if no PCS loop operable or no PCS loop in operation
IMMEDIATELY suspend all operations involving a reduction of PCS boron concentration and initiate action to restore 1 PCS loop to operable and in operation
LCO 3.4.6 “PCS Loops - Mode 4” requirement
2 loops or trains consisting of any combination of PCS loops and SDC trans shall be operable and either 1 PCS loop shall be inoperation, or 1 SDC train shall be in operation with >= 2810 gpm flow through the core
LCO 3.4.6 “PCS Loops - Mode 4” applicability
Mode 4
LCO 3.4.6 “PCS Loops - Mode 4” notes/exceptions
- All PCPs may not be in operation for <= 1 hr per 8 hr period, provided no operations arepermitted that would cause reduction f PCS boron concentration, and core outlet temperature is maintained at least 10 F below saturation temperature.
- Forced circulation (starting the first PCP) shall not be initiated unless PCS cold leg temperature > 430 F, S/G secondary temperature is <= reactor inlet temperature (Tcold), S/G secondary temperature is < 100 F above Tcold and SDC is isolated from the PCS and PCS heatup/cooldown rate is <= 10 F/hr, or S/G secondary temperature is < 100 F above Tcold and SDC is isolated from the PCS and PZR level is <= 57%
- P-50A and P-50B shall not be operated simultaneously due to core lift concerns
LCO 3.4.6 “PCS Loops - Mode 4” required actions if 1 PCS loop inoperable and 2 SDC trains inoperable
IMMEDIATELY initiate action to restore a second PCS loop or one SDC train to operable
LCO 3.4.6 “PCS Loops - Mode 4” required actions if no PCS loops or SDC trains operable or no PCS loop in operation with SDC flow through the core not within limits
IMMEDIATELY suspend all operations involving reduction of PCS boron concentration and initiate action to restore 1 PCS loop to operable and in operation or 1 SDC train to operable and in operation with >= 2810 gpm through the core
What are the differences between P-50A/B/C and P-50D?
- P-50A/B/C have backstop oil pumps, and P-50D has a ratchet and pawl anti reverse rotation device.
- P-50A/B/C have 2 flywheels (upper and lower), and P-50D only has 1 flywheel
What are the PCP starting interlocks?
- P-50A/B/C - 80 gpm CCW flow and 1700 psig lift oil pressure
- P-50D - 145 gpm CCW flow and 675 psig lift oil pressure
What are the PCP power supplies?
P-50A/C - Bus 1A
P-50B/D - Bus 1B
How many seals do the PCPs have?
3 pressure reducing seals and 1 vapor seal
What is the purpose of the PCP vapor seal?
Designed to seal against full system pressure in the event that all 3 seals fail.
What is the purpose/function of the PCP seal heat exchanger?
Cooled by CCW to cool seal water down to 130 F
How is PCP seal water flow controlled?
Throttling controlled bleedoff manual valve between the seals and the VCT
Where is PCP seal water normally routed?
VCT
Where is PCP seal water routed if all 3 seals and the vapor seal fail?
PSDT
What is normal PCP seal flow?
1-1.25 gpm per pump
What are the power supplies for the PCP lift oil pumps?
AC - P-80A/B from MCC-3, P-80C/D from MCC-4
DC - P-81A/C from D-10L, P-81B/D from D-20L
What causes the PCP AC lift oil pumps to auto start?
PCP trip
What causes the PCP DC lift oil pumps to auto start?
- Lift oil pressure < 1700 psig (675 psig for ‘D’ pump) for 5 seconds
- AC lift oil pump trip
- Auto stops after 5 minutes
Why does the DC lift oil pump stop after 5 minutes?
Prevents battery drain
What are the power supplies for the backstop oil pumps for P-50A/B/C?
- P-83A/B/C - MCC-2
- P-84A/B/C - MCC-7
What causes the PCP backstop oil pumps to auto start?
- lift pump start
- PCP start
- if opposite backstop pump flow < 0.24 gpm
How do we determine if a PCP backstop oil pump is running?
- no control room indication
- low flow alarm comes in at 0.24 gpm
- need electricians to use a clamp on ammeter at the breaker cubicle
What is indicated by the white indicating light above the PCP handswitches?
Pump start interlock from lift oil pressure has been met
What is the reason for an abnormal or emergency shutdown of a PCP?
Used to prevent motor damage, and to prevent seal damage that could lead to a LOCA
What is not required when performing an emergency shutdown of a PCP that is required when performing a normal shutdown?
Lift pumps are not required, but it is preferred if the situation allows
What are criteria for PCP emergency shutdown?
- any pump bearing high temperature alarm
- controlled bleedoff high temp 185 F
- high lower seal temperature 185 F
- PCP vibration alarm with supporting indications such as abnormal current, rising bearing temperature, or sudden change in PCS flow
- no PCP backstop oil pump running
- no CCW flow to containment for > 10 minutes
What will happen if you stop a PCP with the reactor reset?
Reactor will trip
What is the minimum pressure for operating a PCP?
- 250 psia
- can be lowered to 235 psia if using narrow range pressure instrument
What is a potential abnormal indication when operating a PCP at low temperature?
Vibrations may be higher than normal
What is the consequence of starting a PCP with S/G temperature higher than PCS temperature?
Larger pressure transient due to sudden heating of the PCS as it flows across the hot secondary water in the S/G
What is indicated if a PCP has vibrations indicated while it isn’t running?
PCP may be reverse rotating. If the pump is started in this condition, the breaker may open on overcurrent
What is the normal pressure breakdown across the PCP seals?
2060 psia PCS pressure, down to 1300-1400 psia after the lower seal, down to approximately 700 psia after the middle seal, down to approximately 30-100 psia after the upper seal
What are the motor starting duty limitations for P-50A/B/C?
- 3 starts with the pump initially at room temperature
- 2 starts if the pump has been operating continuously for >= 20 minutes, or if it has been idle for >= 40 minutes
What are the motor starting duty limitations for P-50D?
- 2 starts if the pump is allowed to coast down to a stop between starts.
- a third start may be made when winding and core have been cooled by running for >= 20 minutes, or if the pump has been idle for >= 45 minutes
What is the concern with starting a PCP with controlled bleedoff pressure less than VCT pressure?
Reverse seal flow can occur and damage the seals
