HPCI - 1.0 Flashcards
Which main steam line supplies HPCI?
C
What is the design basis of the HPCI system?
The HPCI System shall be able to maintain reactor vessel inventory during a loss of coolant accident originating from a 1” or smaller break under the following conditions:
A. Reactor pressure – 200 psig to 1120 psig
B. Design flow rate - 5600 gpm within 35 seconds of initiation (3000 gpm to ‘A’ CS and 2600 gpm to ‘A’ FW)
C. Independent of AC power
What is the power supply of the HPCI main and booster pumps?
the rotation of the HPCI turbine rotor
What are the channel A containment isolation valves?
Outboard:
F003(outboard isolation valve)
F042(suppression pool suction)
Turbine Trip(HV-4880 Turbine Stop)
What are the channel C containment isolation valves?
Inboard:
F002(inboard isolation valve)
F100(Inboard Isolation Valve Bypass)
Turbine Trip(HV-4880 Turbine Stop)
Where does the HPCI booster pump draw suction? Are there auto suction swaps associated with it?
CST(normal) and Suppression Pool(alternate)
a) Low CST Level (68,000 gallons)
b) High Torus level (78.5”)
c) On a suction swap – Torus Suction fully opens before CST suction closes. – always needs a full suction path
What is the cooling water to the HPCI barometric condenser and lube oil cooler?
Portion of the booster pump discharge.
Where do the HPCI discharge paths go to?
- Make Up - reactor vessel is via the A core spray and A feedwater piping system
- Min Flow Line - discharges to the suppression pool
- Test Line - full flow test line that allows testing during normal plant ops. Also used for the pressure control mode of HPCI.
Upon initiation of the HPCI logic are there any time delays present?
Once the initiation relay is actuated the maintaining relay will keep the HPCI logic from being reset for a TD of 20sec. Once that TD is up you can reset the sealed in logic. This time delay allows for a full stroke of the HPCI valves.
What are the initiation signals for HPCI?
1.68 psig Drywell Pressure
-38 inches Reactor Water Level
MANUAL (Arm/Depress)
HPCI will NOT automatically initiate unless the turbine exhaust valve (HV-F071) is full open
What are all isolation signals for HPCI?
FART Man Ruptures on Hi D/P to Supply Pressure
1. FART (Four Area Room Temps)
a) HPCI Room Ventilation Hi dT ≥ 70 F (1 sec TD)
b) Equipment Area (HPCI Rm) Hi Temp ≥ 160 F (1 sec TD)
c) HPCI Steam Pipe Area Hi-Hi Temp ≥ 160 F (15 min TD)
d) Torus Room Hi temp ≥ 128 F (15 min TD)
2. MANual (Isolation can only be accomplished if a HPCI initiation signal is sealed in and the PB is depressed (A channel only).
3. Rupture diaphragm Hi pressure ≥ 10 psig.
4. Hi D/P HPCI Steam Supply
a) ≥ 1032” H2O (4 sec TD), (300% Rated Flow)
b) - 50” H2O (4 sec TD), (Instrument Line Break)
5. Supply Pressure Low: ≤ 100 psig
6. HPCI ISOLATION MISC
a) If an isolation signal comes in, HPCI isolates by closing inboard and outboard isolation valves
b) If the isolation signal originates from the ISLN LOGIC PB’s, HPCI needs to have an initiation signal already present or else it will not isolate. – man pb counts as a valid initiation signal
What is the HPCI normal pump flow rate?
5,600 GPM (3,000 GPM to A CSS and 2,600 GPM to A FW)
What is the HPCI overspeed trip?
> 125% (~5,200 RPM)
What is the HPCI overspeed reset?
2,500 – 3,000 RPM (auto re-opens the FV-4880)
When does the HPCI minimum flow valve open and close?
- Opens when <550 GPM flow (AND pump disch > 125 PSIG) [normally closed until initiation]
- Closes when >550 GPM flow (OR FV-4880 not open OR F001 full closed)
What is the CST reserve capactiy?
135,000 Gallons
What is the HPCI low supply pressure isolation?
≤ 100 PSIG
What are the HPCI exhaust pressures?
140 # Trip / 175 # Rupture / 10 # Isolation dwnstrm of disc)
What are the HPCI Turbine trips?
Overspeed - 125%(5200 rpm)
Isolation signal - Auto or Man for Channel A and/or C
Level 8 - +54”
Manual Trip PB
Exh Press Hi - 140 psig
Suction Press - 15” hg VAC Booster Pump Suction
OILMES
When a HPCI turbine trip occurs, what valves are affected and how?
For all trip conditions, HPCI turbine stop valve FV-4880 will close causing the closure of:
HV-F006, PMP DSCH TO CS ISLN
HV-8278, PMP DSCH TO FW ISLN MOV
HV-F012, MIN FLOW BYP MOV
Are all HPCI trips sealed in until manually reset?
No, only the High Rx Vessel water level resets itself at -38” after a high level trip and realigns to inject water automatically. Above this setpoint it remains locked in until manually reset.
What is the actuation sequence after a valid HPCI initiation?
- Aux Oil Pump Starts (allows opening control valves)
- Vacuum pump Starts
- F001 (Steam Line Stop Valve) OPENS (IF F071 open)
- Once F001 Opens
a) Steam line drain pot to Main Condenser and Cond Pump return to CRW close. - FV4880 is normally shut and needs oil to (Turbine Stop Valve) OPEN
- FV-4879 (Control valve) OPENS
- F004 (CST Suction) OPENS (IF F042 not full open)
- F007 (Pump Disch Valve), F006 (Disch to ‘A’ Core Spray), HV8278 (Disch to FW ‘A’) OPEN
- F059 (Booster Supply to Barometric Condenser) OPENS
- F012 (Min Flow Valve) CYCLES as needed
- F008 (Full flow test return to CST) CLOSES
- F011 (HPCI/RCIC common full flow test return to CST for reactor pressure control) CLOSES – RCIC runs on minflow if it was in full flow test CST to CST
- HV-4922 (vacuum pump disch to main condenser) CLOSES with initiation signal
What happens if RCIC is using the common HPCI/RCIC test line and HPCI acuates?
F011 (HPCI/RCIC common full flow test return to CST for reactor pressure control) CLOSES – RCIC runs on minflow if it was in full flow test CST to CST
When does the pump suction swap it’s make up source?
CST ≤ 68,000 Gal
OR
Torus ≥ 78.5”
What are the DIV 1 (‘A’ Channel) Containment Isolation valves?
DIV 1 (‘A’ Channe) (Outboard)
a) F003 (Outboard Isolation Valve)
b) F042 (Suppression Pool Suction)
c) Turbine Trip (HV-4880, Turbine Stop)
What are the DIV 3 (‘C’ Channel) Containment Isolation valves?
DIV 3 (‘C’ Channel) (Inboard)
a) F002 (Inboard Isolation Valve)
b) F100 (Inboard Isolation Valve Bypass)
c) Turbine Trip (HV-4880, Turbine Stop)
What is the HPCI Jockey pump low suction trip?
15” HgVac
When does the HPCI Booster pump swap suction path?
a) Low CST Level (<68,000 gallons)
b) High Torus level (>78.5”)
c) On a suction swap – Torus Suction fully opens before CST suction closes. – always needs a full suction path
Describe the operation and interlocks for the Aux Oil Pump.
a) Starts whenever HPCI Initiation Signal is present and discharge pressure is <30-40psig. Pump stops once pressure increases above 90-95psig.
b) Interlocked with F001. Pump will not start if F001 is full closed (this is bypassed after a 12 second TD) to prevent overpressurizing the downstream piping. Once open and spun up to provide oil, interlock is bypassed.
c) HPCI cools its own oil – cooler supplied by torus water
d) HPCI turbine supplies its own hydraulic oil after reaching speed. If HPCI trips, aux oil pump is needed to start HPCI again.
A closure of F001 will cause which valves to close?
- 8278 - Pump discharge to FW
- F012 - Pump min flow to Torus
- F006 - Pump Discharge to CS
A closure of F001 will cause which valves to open?
- F028 / F029 - Inboard and outboard steam drain isolations
- F026 / F025 - Barometric condenser inboard and outboard discharge to CRW – closes when F001 opens w.o initiation signal – switches paths to recycle into pump suction when HPIC is in service
What are precautions associated with HPCI pump speed operating below a certain speed?
Operations below 2150RPM causes excessive check valve chatter and bearing damage.
When can controllers have instabilities?
Below 4275gpm the flow controller has flow instabilities.
What is the first thing that should be put in service for HPCI operation?
Ensure HPCI VAC TK vacuum pump running and aux oil pump
Where does HPCI read flow?
HPCI reads flow downstream of the min flow valve – ONLY SEES WHAT GOES TO THE VESSEL / CST (this is true of all systems)
What is the sequence for the suction swap?
a) F004 opens on HPCI initation (if F042 not full open)
b) On high torus water level or low CST level, F042 opens
c) Once F042 is full open, F004 closes – HPCI always needs a suction path
d) F042 has an auto open override to use when it is necessary to swap back to the CST (i.e. when using HPCI in pressure control)
What is important about F071?
HPCI will not start unless the exhaust to torus valve F071 is open (F071 has no auto functions) – F001 will not open if F071 not open
What happens when HPCI INIT is sealed and and you press the close PB for F006 or F8278?
If HPCI INIT and sealed in and working properly, if you press close on F006 or F8278, they will stroke closed then immediately reopen.
What happens if the turbine EXH valve is closed?
If the exhaust valve is closed, the HPCI turbine will trip on hi exh pres, then the first diaphragm will blow, then a HPCI isolation will occur, then the downstream diaphragm will blow.
When does the VAC BKR isolate?
F075 and F079 close on Hi DW pressure and Low supply pressure (100#).
When does F011 close?
- RCIC F031 open.
- HPCi F042 open.
- HPCI initiaton.
Describe the normal operation of the Barometric Condenser Vacuum Pump.
Maintains vacuum and removes non condensable gasses from system and normally discharges to RBE/FRVS, but can go to MC.
Where does the barometric condensate pump discharge to?
- Discharged to CRW when HPCI is S/D.
- Discharged to HPCI booster pump suction when HPCI is I/S.
