Safety Injection Flashcards
LCO 3.3.3 “Engineered Safety Features (ESF) Instrumentation” requirement
4 ESF bistables and associated instrument channels shall be operable for SIS PZR Low Pressure, RAS SIRWT Low Level, and PZR Low Pressure Bypass.
LCO 3.3.3 “Engineered Safety Features (ESF) Instrumentation” applicability for SIS/RAS functions
Modes 1-3
LCO 3.3.4 “Engineered Safety Features (ESF) Logic and Manual Initiation” requirement
2 ESF Manual Initiation and 2 ESF Actuation Logic channels and associated bypass removal channels shall be operable for SIS and RAS.
LCO 3.3.4 “Engineered Safety Features (ESF) Logic and Manual Initiation” applicability for SIS/RAS functions
Modes 1-3
LCO 3.3.8 “Alternate Shutdown System” requirement
The Alternate Shutdown System functions for PZR pressure and SIRWT level shall be operable
LCO 3.3.8 “Alternate Shutdown System” applicability for SIS/RAS
Modes 1-3
LCO 3.4.14 “PCS Pressure Isolation Valve (PIV) Leakage” requirement
Leakage from each PCS PIV shall be within limits and both SDC suction valve interlocks shall be operable.
LCO 3.4.14 “PCS Pressure Isolation Valve (PIV) Leakage” applicability
Modes 1-3
Mode 4, except during the SDC mode of operation, or transition to or from the SDC mode of operation
LCO 3.5.1 “Safety Injection Tanks (SITs)” requirement
4 SITs shall be operable
LCO 3.5.1 “Safety Injection Tanks (SITs)” applicability
Modes 1-2
LCO 3.5.1 “Safety Injection Tanks (SITs)” required action if 2 or more SITs are inoperable
IMMEDIATELY enter LCO 3.0.3
LCO 3.5.2 “Emergency Core Cooling Systems (ECCS) - Operating” requirement
2 ECCS trains shall be operable
LCO 3.5.2 “Emergency Core Cooling Systems (ECCS) - Operating” applicability
Modes 1-2
Mode 3 with PCS temperature >= 325 F
LCO 3.5.2 “Emergency Core Cooling Systems (ECCS) - Operating” required actions if less than 100% of the required ECCS flow available
IMMEDIATELY enter LCO 3.0.3
LCO 3.5.3 “Emergency Core Cooling Systems (ECCS) - Shutdown” requirement
1 LPSI train shall be operable
A LPSI train may be considered operable during alignment and operation for SDC if capable of being manually re-aligned to the ECCS mode of operation
LCO 3.5.3 “Emergency Core Cooling Systems (ECCS) - Shutdown” applicability
Mode 3 with PCS temperature < 325 F
Mode 4
LCO 3.5.3 “Emergency Core Cooling Systems (ECCS) - Shutdown” required action if required LPSI train inoperable
IMMEDIATELY initiate action to restore 1 LPSI train to operable
LCO 3.5.4 “Safety Injection Refueling Water Tank (SIRWT)” requirement
The SIRWT shall be operable
LCO 3.5.4 “Safety Injection Refueling Water Tank (SIRWT)” applicability
Modes 1-4
LCO 3.5.4 “Safety Injection Refueling Water Tank (SIRWT)” required action if SIRWT is inoperable for reasons other than boron concentration or borated water temperature not within limits
WITHIN 1 HOUR, restore SIRWT to operable
LCO 3.5.5 “Containment Sump Buffering Agent and Weight Requirements” requirement
Buffer baskets shall contain >= 8,186 lbs and <= 10,553 lbs of Sodium Tetraborate Decahydrate (STB)
LCO 3.5.5 “Containment Sump Buffering Agent and Weight Requirements” applicability
Modes 1-3
What is required for a SIT to be operable?
- Level < 66% and > 14%
- Boron < 2500 ppm and > 1720 ppm
- Pressure > 200 psig
- Drain and fill and vent valves closed
What is required for the SIRWT to be operable?
- Boron < 2500 ppm and > 1720 ppm
- > 250,000 gallons of water (85%) in Modes 1-3, 200,000 gallons of water (67%) in Mode 4. Admin limit is 275,970 gallons (92%)
- Temperature < 100 F and > 40 F
What is the required to meet the design basis of the Safety Injection System?
- 3 SITs
- 1 HPSI pump
- 1 LPSI pump
- 1 EDG
- 25% of SI flow assumed to be going out the PCS break
What is the purpose of CV-3027 and CV-3056, SIRWT Recirc Valves?
Provide a flow path to recirculate HPSI/LPSI pumps back to the SIRWT to prevent dead heading the pumps
What is the required position of CV-3027 and CV-3056, SIRWT Recirc Valves, on RAS.
Required position is closed to prevent highly radioactive water from the sump from going to the SIRWT, and to prevent a loss of inventory to the SIRWT.
How can CV-3027 and CV-3056, SIRWT Recirc Valves, be closed?
Each valve has 2 switches, 1 handswitch and 1 keyswitch. To close these valves, both switches need to be taken to the close position. Valves will also close automatically on RAS if the handswitch is taken to close prior to receiving the RAS signal (this “arms” the valves for RAS).
What is the motive force for operating CV-3027 and CV-3056, SIRWT Recirc Valves?
- HP air (normal)
- Nitrogen (backup) good for 24 hours
How do CV-3027 and CV-3056, SIRWT Recirc Valves, fail on a loss of air?
As is
What is the purpose/function of CV-3031 and CV-3057, SIRWT Outlet Valves?
Provide a flow path from the SIRWT to the HPSI/LPSI/CS pumps.
What position do CV-3031 and CV-3057, SIRWT Outlet Valves, go to on RAS?
Closed
What is the motive force for operating CV-3031 and CV-3057, SIRWT Outlet Valves?
- HP air (normal)
- Instrument air (backup)
How do CV-3031 and CV-3057, SIRWT Outlet Valves, fail on a loss of air?
As is
What is the purpose/function of CV-3029 and CV-3030, Containment Sump Outlet Valves?
Open on low SIRWT level to provide a suction source for the HPSI/LPSI/CS pumps when the SIRWT goes away.
What position do CV-3029 and CV-3030, Containment Sump Outlet Valves, go to on RAS?
Open
What is the motive force for operating CV-3029 and CV-3030, Containment Sump Outlet Valves?
- HP air (normal)
- Instrument air (backup)
How do CV-3029 and CV-3030, Containment Sump Outlet Valves, fail on a loss of air?
As is
What is the interlock if CV-3030, Containment Sump Outlet Valve to left train, fails to open
- ‘B’ HPSI pump subcooling valve won’t open
- CV-3001, left train containment spray header isolation, will close after 30 seconds
What are the power supplies for the HPSI pumps?
P-66A - D bus
P-66B - C bus
What is the design flow of the HPSI pumps?
300 gpm at 1084 psia
What is the minimum flow requirement for the HPSI pumps?
25 gpm
What is the cooling water supply for the HPSI pumps?
CCW
What is the purpose/function of CV-3070 and CV-3071, HPSI Pump Subcooling Valves?
Provides a flow path to the suction of the HPSI pumps from the discharge of the Containment Spray Pumps through the SDC Heat Exchanger. This is to prevent cavitation of the HPSI pumps when the suction source swaps to the containment sump.
What is the motive force for operating CV-3070 and CV-3071, HPSI Pump Subcooling Valves?
- Instrument air (normal)
- Nitrogen (backup)
How do CV-3070 and CV-3071, HPSI Pump Subcooling Valves, fail on a loss of air?
Closed
What are the interlocks to auto open CV-3070, B HPSI Pump Subcooling Valve?
- RAS
- CV-3030, Containment Sump Outlet Valve, open
- ‘B’ HPSI Pump running
What are the interlocks to auto open CV-3071, A HPSI Pump Subcooling Valve?
- RAS
- ‘A’ HPSI Pump running
Which pump is normally aligned to supply the RHPSI header?
P-66A, HPSI Pump
How does the flow path work for hot leg/cold leg injection?
Restricting orifice in the normal flow path from the HPSI pumps to the cold legs. MOV bypass around the orifice is normally open to allow unrestricted flow to the cold legs. Off of the bypass line, upstream of the bypass MOV, a line taps off and goes through another MOV to the hot legs. This MOV is interlocked so it can only be opened if the orifice bypass MOV is closed. When hot leg and cold leg injection is desired, the orifice bypass MOV is closed, and the MOV to the hot leg is opened. This places the restricting orifice in service to reduce flow to the cold legs, and divert the rest of the flow to the hot leg.
What is the purpose/function of hot leg injection?
Placed in service ~5.5-6.5 hours into the event to prevent boric acid buildup on the top of the core.
What are the power supplies for the HPSI Train 1 Loop Injection Valves, CV-3007, 3009, 3011, 3013?
MCC-1
What are the power supplies for the HPSI Train 2 (Redundant HPSI) Loop Injection Valves, CV-3062, 3064, 3066, 3068?
MCC-2
What are the power supplies for the LPSI pumps?
P-67A - D bus
P-67B - C bus
What is the design capacity of the LPSI pumps?
3000 gpm at 152 psia
What is the minimum flow of the LPSI pumps?
170 gpm
What is the cooling water supply for the LPSI pumps?
CCW
What auto starts/trips the LPSI pumps?
- Start on SIS
- Trip on RAS (can be disabled with a key switch)
When is the keyswitch used to disable LPSI pump trip on low SIRWT level?
During refouts when SIRWT is transferred to the RX cavity, so the LPSI pump will continue operating to supply SDC.
What is the purpose/function of the LPSI Pump Suction MOVs, MO-3189, 3190, 3198, 3199?
Determines if LPSI pumps take suction from SIRWT or SDC. Normally lined up to SIRWT.
What are the power supplies for the LPSI Loop Injection Valves, MO-3008, 3010, 3012, 3014?
Loop 1 Injection (MO-3008, 3010) - MCC-1
Loop 2 Injection (MO-3012, 3014) - MCC-2
What is the purpose/function of the SITs?
Passive system filled with borated water that will inject into the PCS when pressure drops to approximately 250 psia.
What are the SIT level setpoints for tech specs and alarms?
- Tech Spec High - 66%
- Hi level switch alarm - 62%
- Hi/Lo level alarm (Hi) - 48%
- Hi/Lo level alarm (Lo) - 32%
- Low level switch alarm - 18%
- Tech Spec Low - 14%
What are the SIT boron concentration limits?
1720-2500 ppm not inclusive
What are the SIT pressure limits?
- Normal - 210-215 psig
- Tech Spec - 200 psig
- Relief valve setpoint - 250 psig. Won’t reseat until 175 psig (long blowdown).
What is the normal online position of the SIT Outlet Valves, MO-3041, 3045, 3049, 3052?
Normally electrically locked open and de-energized to prevent a failure from keeping the SIT from working.
When would we close the SIT Outlet Valves, MO-3041, 3045, 3049, 3052?
When PCS pressure is 1300-1500 psig to prevent inadvertent discharge into the PCS during normal plant cooldown.
What causes SIS to initiate?
- 2/4 low pzr pressure of 1605 psia
- CHP of 4 psig 2/4 logic
- Manual push button
What is the purpose/function of SIS Block?
- Used during controlled plant cooldowns to prevent actuating SIS.
- 2 block switches (1 per channel)
- When 3/4 PZR pressure < 1690 psia, but > 1605 psia, hold switch for each channel in BLOCK until “SIS Block” alarm comes in
What SIS functions are still available when SIS is blocked?
SIS actuation on CHP or manual
How is SIS block removed/reset?
2/4 PZR pressure > 1690 psia
How is SIS disabled?
Have to remove fuses to disable SIS on CHP
When do we disable SIS?
Modes 4-6 to prevent any actuation of SIS
What equipment actuates on SIS?
- LPSI Pumps start
- HPSI Pumps start
- SW Pumps start
- CCW Pumps start
- Charging Pumps start
- Containment Spray Pumps “arm” to start on CHP
- Boric Acid Gravity Feed Valves open
- VCT Outlet Valve closes
- Non-Critical Service Water Header Isolation closes
- SDC HX CCW outlets open
What is the purpose/function of RAS?
Switches ESS pump suction from SIRWT to Containment Sump.
What causes RAS to actuate?
SIRWT low level of 2%. Logic is 1/2 taken twice, so each channel looks at all 4 level transmitters (2 right train and 2 left train).
What equipment actuates on RAS?
- Containment Sump Outlet CVs open
- SIRWT Outlet CVs close
- SIRWT Recirc CVs close (if armed)
- CCW HX High Capacity SW Outlet valves open to their hard stops
- LPSI Pumps trip
- HPSI Pump Subcooling Valves open (if interlocks are made up)