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Front 1

State the purpose of the High Pressure Coolant Injection (HPCI) System. (3)

Back 1

The HPCI System has the following functions:

- Provide coolant to reactor vessel following a Small Break LOCA until reactor vessel pressure is below the pressure at which CS and LPCI can maintain core cooling.

- Provide sufficient coolant to prevent the actuation of the ADS and maintain reactor level above the top of the reactor core in the event of a small pipe break 1 squr in or smaller.

- Additionally, the HPCI system may be used to maintain reactor water level and aid in pressure control during a reactor isolation.

Front 2

ECCS Design Basis (5)

Back 2

Prevent the following:
• Peak cladding temperature < 2200F
• Maximum cladding oxidation < 0.17 time the total cladding thickness before oxidation
• Maximum hydrogen generation < 0.01 times the hypotheitical max
• Coolable geometry
• Long-term cooling

Front 3

purpose and operation
Turbine Exhaust Rupture Diaphragms

Back 3

Two diaphragms in series located on turbine exhaust line designed to prevent damage to exhaust piping due to over pressure.

- Diaphragms will break on high exhaust pressure (>175 psig) and turbine exhaust will discharge to the HPCI room

- Pressure switch between diaphragms. Initiates HPCI Isolation on high turbine diaphragm exhaust pressure (PIS-*N655B, D, F, H, set at 10 psig)

Front 4

purpose and operation
Booster pump

Back 4

Single stage, Centrifugal pump, rated for 5670 gpm at 450 psig
- 5600 gpm for NPSH for main pump
- 70 gpm cooling water flow to lube oil cooler and barometric condenser

Driven by turbine via reduction gears - (Reduction ratio of 2:1, pump runs at 1/2 turbine speed)

Takes suction from CST (preferred source) Suppression Pool (T.S. and backup source)

Discharges to Main Pump suction

Front 5

purpose and operation
Barometric Condenser

Back 5

Collects drains from condesnate, steam, and non-condensable gasses.
Spargers spray water from Booster Pump discharge into steam volume to cool and condense steam
Non-condensibles drawn off by Vacuum Pump
Liquid removed by Condensate Pump

Front 6

purpose and operation
Vacuum pump

Back 6

1) Automatically starts on a system initiation, and maintains negative pressure in Barometric Condenser
2) Discharges to Reactor Enclosure Equipment Compartment Exhaust (REECE)

Front 7

purpose and operation
Exhaust Line Vacuum Breakers (HV-55-*F093 & HV-55-*F095)

Back 7

1) Normally open to prevent drawing water (which will cause water hammer on next HPCI start) from suppression pool into exhaust line after HPCI run.

2) Automatically close upon
a) High Drywell pressure 1.68 psig
AND
b) Low HPCI steam supply pressure 100 psig

3) HV-55-*F093 is powered from safeguard MCC D*24-R-G1, HV-55-*F095 is powered from safeguard MCC D*44-R-E.
a) Loss of AC will prevent an isolation but will not prevent a system initiation

Front 8

purpose and operation
HPCI lube oil

Back 8

Provides Turbine and Main pump with Hydraulic operating oil, Control oil, and Lubricating oil.

Front 9

purpose and operation
HPCI lube oil
DC Motor-Driven pump (Aux Oil Pump)

Back 9

1) Automatically starts with HPCI initiation
2) Provides oil during turbine start-up and shutdown (Automatically starts with decreasing pressure (about 1500-1200 turbine RPM))
3) Supplies oil at 85-90 psig for - Control Valve operation and Turbine lubrication
4) Motor Driven Pump automatically stops when Shaft Driven pump develops pressure
5) Driven by 250 VDC motor (Power from *DB-1)

Front 10

purpose and operation
HPCI lube oil
d. Shaft Driven pump

Back 10

1) Driven by low speed shaft and is connected by a worm gear arrangement
2) Supplies oil for normal operation
a) 105-110 psig
b) Developed at 1450-1650 RPM

Front 11

purpose and operation
HPCI lube oil
e. Lube oil cooler

Back 11

1) Cools oil from lube oil sump
2) Cooling water supplied by booster pump discharge

Front 12

purpose and operation
HPCI turbine

Back 12

a. Steam from “C” Main Steam Line is supplied to the HPCI turbine. Turbine exhaust steam is directed to the Suppression Pool
b. Steam flow (75,000-184,500 lbm/hr)
c. Steam pressure (200-1182 psig)
d. Exhaust pressure (25-65 psia)
e. HPCI speed (2150-4190 RPM) (Speed administratively maintained greater than 2200 rpm to minimize exhaust line oscillations)
f. Time from rest to rated speed less than 60 seconds

Front 13

Condensate Storage and Transfer System (CST) supports the operation of the HPCI

Back 13

1) A loss of CST Level would have no effect on HPCI operation provided the suction swapped to the Suppression Pool and Suppression Pool level is within limits
- CST is the preferred suction source for the HPCI pump
- Primary source of water to keep HPCI discharge piping full to ensure instantaneous injection and prevent water hammer on system start

Front 14

Suppression Pool supports the operation of the HPCI

Back 14

1) Suppression Pool Level
a) A loss of Suppression Pool level would have no effect on HPCI operation provided suction is from the CST and CST level is adequate. HPCI would however be Inop per Tech Specs
b) Low SP level will result in insufficient NPSH to the ECCS and RCIC systems.
IF SP level cannot be maintained above the HPCI turbine discharge pipe (18’), operation of HPCI will directly pressurize containment.

2) Suppression Pool Temperature / Pressure
a) An increase in SP temperature affects the NPSH and vortex limits of pumps taking suction on the SP. (Vortex limits are the lowest SP level above which air entrainment is not expected to occur to the pumps)
c) Elevated SP pressure will cause the HPCI turbine to trip earlier than expected due to increased backpressure on the turbine (140psig).
Reduced SP pressure will tend to reduce NPSH available to the pumps.

Front 15

Core Spray System supports the operation of the HPCI

Back 15

- ~45% of HPCI flow is fed to vessel via the "B" core spray loop

Front 16

Feedwater System supports the operation of the HPCI

Back 16

- ~55% of HPCI flow is fed to vessel via the "A" Feedwater line
- FW/CS injection split minimizes impact of HPCI ops during ATWS event; minimizes thermal peaking in bundles adjacent to stuck rods.

Front 17

Main Steam System supports the operation of the HPCI

Back 17

- Steam from “C” Main Steam Line is supplied to the HPCI turbine.

Front 18

DC Distribution System supports the operation of the HPCI

Back 18

- DC lube oil pump driven by 250 VDC motor

Front 19

AC Distribution System supports the operation of the HPCI

Back 19

1) A loss of AC Power will prevent an isolation but will not prevent a system initiation. If an isolation becomes necessary, the Outboard Isolation Valve can be manually closed locally with the manual handwheel. Both Steamline Isolation Valves are AC powered
2) Also prevents closing Vacuum Bkr Isolation Valves. Both valves are outside containment and accessible

Front 20

Liquid Rad Waste System supports the operation of the HPCI
- Condensate drains to Radwaste (HV-55-*F025 & HV-55-*F026)

Back 20

AOVs
- *F025
- Normally open.
- Automatically shuts if Turbine Steam Supply *F001 is not fully shut.
- If closed, valve will not open unless *F001 is fully shut.

- *F026
- Normally closed.
- Opens and closes on vacuum tank high and low level respectively
- Automatically closes if Turbine Steam Supply Valve *F001 is not fully shut

Front 21

HPCI Minimum Flow Valve (HV-55-*F012) Interlocks

Back 21

Normally Closed; opens to provides minimum flow protection to pump and prevents inadvertent draining of CST to the Suppression Pool

OPEN signal if
- System flow is low AND sufficient pump discharge pressure
- Opens at <550 gpm AND greater than 125 psig

CLOSED signal if either:
- Sufficient system flow (650 gpm), or
- Turbine Steam Supply (*F001) fully shuts, or
- Turbine stop valve (FV-*12) fully shuts

Front 22

Identify the conditions, including setpoints that will cause a HPCI automatic initiation.

Back 22

- RPV low water level (-38”) OR
- High drywell pressure, (1.68 psig) OR
- Manual (arm and depressed pushbutton for ~13 seconds to fully initiate HPCI)
(13 seconds allows time for injection valves (*F006 and *F105 to receive open signals))

Front 23

Identify the sequence of events that occur when a HPCI system automatic initiation signal is received.

Back 23

- HV-55-*F001, HPCI Turbine Steam Supply Valve opens (ONLY IF exhaust valve is open)
- Motor Driven Auxiliary Oil Pump starts
- Barometric Condenser Vacuum Pump starts
- Once the Auxiliary Oil Pump is delivering sufficient oil pressure:
- TSV and Governor Control Valve open (controlled by ramp generator)
- When TSV and 001 Valve not fully closed, HV-55-*F006, HPCI Pump Discharge to Core Spray, and the HV-55-*F105, HPCI Pump Discharge to Feedwater, valves open
- CST suction (004) gets an open signal; test return valves (008, 011 and 071) get closed signal.

Front 24

Identify the requirements for resetting a HPCI system automatic initiation.

Back 24

- The method HPCI system is shutdown is determined by if the initiation signal can be reset

- If the initiation signal is no longer present, (white seal-in light can be reset)
- Simultaneously depress turbine trip PB and close Steam Supply Valve *F001

- If initiation signal is present (white seal-in light cannot be reset)
- Ensure Barometric Condenser Vacuum Pump and Aux Oil Pump are running
- Depress the Manual Isolation Pushbutton
- OR -
- Place HPCI flow controller in manual and lower speed (above 2200 rpm) such that HPCI is no longer injecting

Front 25

a.          Identify the conditions, including setpoints, that will cause a HPCI system automatic isolation.

Back 25

1) The automatic HPCI system isolation logic is divided into two logic systems, and actuates upon receiving any of the following:

DIVISION II or DIV IV
a) Low steam supply pressure - 100 psig
b) High steam line flow - 974" wc with a 3 second time delay
c) High temperatures - Requires NORMAL/BYPASS switch to be in NORMAL
(1) Equipment area DT - 104°F
(2) Equipment area - 225°F
(3) Steam supply piping area - 175°F
d) Turbine diaphragm exhaust pressure high - 10 psig

DIVISION II ONLY
e) Manual - Pushbutton depressed (S32) with an initiation signal present

Front 26

b.          Identify the sequence of events that occur when a HPCI system automatic isolation signal is received.

Back 26

Div. 2 Isolation Signal:
1) The following HPCI system valves close:
a) HV-55-*F003, HPCI Steam Line Outboard Isolation
b) HV-55-*F041 and HV-55-*F042 HPCI Pump Suction Valves from the Suppression Pool
c) HV-55-*F100, HPCI Steam Line Warmup Bypass
2) The HPCI Turbine receives an automatic trip signal

Div. 4 Isolation Signal:
1) HV-55-*F002, HPCI Steam Line Inboard Isolation Valve, auto closes
2) The HPCI Turbine receives an automatic trip signal
T-LOT-0340-5 for the resetting of a system isolation using:

Front 27

c.          Identify the requirements for resetting a HPCI system automatic isolation.

Back 27

The isolation can be reset when:
1) Reactor pressure is greater than 100 psig,
AND
2) The cause of the system isolation has been determined and corrected.

3) The associated handswitch for the isolated valve is placed in the closed position prior to resetting (not an interlock).
4) Repressurize slowly using the HPCI steam line warmup bypass (HV-55-*F100) to minimize thermal shock.

Front 28

a.          Identify the conditions, including setpoints, that will initiate an automatic HPCI turbine trip.

Back 28

4. AUTOMATIC TRIPS

a. The HPCI turbine will automatically trip upon receiving any of the following signals:

1) High turbine exhaust pressure 140 psig
2) Low pump suction pressure 15" Hg vacuum
3) High reactor level +54" (wide range) (will seal in and reqiures operator to depress the reset switch)
a) +54" RPV water level will cause excessive moisture carry-over and turbine damage may result
b) OT-110, Reactor High Level, directs both isolation valves (*F002 and *F003) closed to protect down stream piping and turbine blading due to an overfilling event from low pressure systems (directed at +100" AND level rise cannot be controlled)
4) Low steam supply pressure - 100 psig
5) Div-2 isolation
6) Div-4 isolation
7) Manual trip
8) Manual shutdown from RSP (NOT A TURBINE TRIP) Control Valves closes due to removal of DIV II control power

b. In addition, to the above listed automatic trips, the HPCI Turbine will auto trip on an overspeed condition, as outlined below:
HPCI overspeed automatically resets as speed is reduced
1) At a predetermined RPM, a pin type mechanical emergency trip weight is displaced by centrifugal force (125% or 5238 rpm)
2) The pin strikes a ball tappet assembly, lifting the tappet and a connected hydraulic trip piston upwards, overcoming the reset spring force of the piston
3) With the piston raised, internal ports are uncovered, dumping control oil, causing the TSV to close
4) Once turbine speed is reduced for a predetermined time (3-6 sec), the trip will automatically reset (via realignment of ports) allowing a restart of the turbine

Front 29

b.          Identify the sequence of events that occur following a HPCI system automatic trip signal.

Back 29

c. The following events occur upon receiving a HPCI Turbine Trip signal
1) The Turbine Trip Auxiliary Relay, K37, is energized which energizes solenoid valve SV1. With SV1 energized, control oil is dumped, depressurizing the control oil lines, allowing spring pressure to close the TSV, isolating steam to the turbine (With the TSV full closed, HPCI Pump Discharge Valves F006 and F105 and Minimum Flow Valve F012 receive auto close signals)

Front 30

c.          Identify the requirements for resetting an automatic trip.

Back 30

d. S55.1.C, Recovery from HPCI Turbine Trip, the trip can be reset when:
1) The cause of the turbine trip has been determined and corrected,
AND

2) The isolation has been reset per S55.1.B, Recovery from System Isolation, if applicable.
3) If the HPCI System was initiated by an automatic initiation and was shutdown by a RPV high level signal (FV-56-112 closed and RPV high level light lit) then HPCI will only restart on subsequent low RPV level initiation.
4) The RPV high level signal (+54”) must be manually reset to allow HPCI to auto start on high drywell pressure or a manual initiation

Front 31

methods used to prevent water hammer in:
a. HPCI turbine exhaust line

Back 31

- Vacuum Breakers (HV-55-*F093 & HV-55-*F095) prevent drawing water from suppression pool into exhaust line after HPCI run. Minimizing water in the HPCI exhaust line will prevent water hammer on the next HPCI start

Front 32

methods used to prevent water hammer in:
b. HPCI pump discharge line.

Back 32

- The CONDENSATE STORAGE and TRANSFER SYSTEM, backed up by the KEEP FILL SYSTEM provides a source of water to keep HPCI discharge piping full to ensure instantaneous injection and prevent water hammer on system star

Front 33

Predict the operation of the HPCI turbine ramp generator during an automatic or manual HPCI system start.

Back 33

- The ramp generator overrides the flow controller during turbine startup to allow a controlled rate of acceleration. Once the ramp generator output exceeds the signal from the flow controller, the controller takes over and maintains control until the ramp generator is reset. The ramp generator is reset whenever the turbine stop valve is fully closed

Front 34

Predict the sequence of events that occur during a HPCI system manual initiation.

Back 34

a. In addition to the automatic HPCI system initiation signals, the HPCI system may be manually initiated (arm and depress PBs) under the following condition:
1) When directed by the TRIP procedures to maintain RPV level or pressure

b. The HPCI system may also be manually initiated by S55.1.D, HPCI System Full Flow Functional Test, by performing the following:
1) Start the Barometric Condenser Vacuum Pump
2) Opening the HV-55-*F011, HPCI/RCIC Test Return to the CST Header
3) Perform either a Manual Slow Start or a Manual Quick Start, as follows:
a) Per S55.1.D, severe exhaust line oscillations may develop
b) Manufacturer's concerns that at lower speeds, adequate water flow may not exist to provide required lube oil cooling or condensate spray for steam condensing in the Barometric Condenser

a) For a Manual Slow Start:
(1) Place the flow controller in manual and reducing the output signal to 0
(2) Open the HPCI Turbine Steam Supply Valve, HV-55-*F001
(3) Start the Auxiliary Oil Pump and observe the TSV open
(4) Verify cooling water valve opens
(5) Slowly raising the flow controller output to greater than 2200 RPM.
(6) Immediately throttle open the HV-55-*F008, HPCI Test Loop shutoff as soon as speed is observed.

b) For a Manual Quick Start:
(1) With the flow controller in auto and set at 5600 gpm, simultaneously opening the HPCI Turbine Steam Supply Valve, HV-55-*F001, and start the Auxiliary Oil Pump.
(2) Immediately throttle open the HV-55-*F008, HPCI Test Loop shutoff as soon as speed is observed

c. HPCI may be used for level control and/or pressure control. To transfer HPCI from pressure control mode to injection mode or from injection mode to full flow test then operations should be performed in accordance with S55.7.A, Transfer of HPCI from Pressure Control Mode to Injection Mode and Back

d. Once the HPCI system is no longer required to aid in maintaining RPV level and/or pressure control, or the full flow test is complete, the HPCI system may be shutdown by manually tripping the turbine, holding the "Turbine Trip" pushbutton depressed, while simultaneously closing the HPCI Turbine Steam Supply Valve, HV-55-*F001

Front 35

Identify the method of turbine speed control and pump flow control during HPCI operation.

Back 35

- Speed Control (MANUAL): In MANUAL, THE flow controller will operate THE governor In an isochronous mode, throttling THE Control valve to maintain Speed constant
- flow Control (AUTO): In AUTO, THE flow controller receives an input from pump flow and compares THE flow SIGNAL with A flow setpoint. If actual flow is less than THE setpoint, THE governor will send A SIGNAL to THE Control valve to throttle open until they agree

Front 36

c. HPCI system
- Suppression Pool Suction Valves (HV-55-*F041, HV-55-*F042)

Back 36

- Suppression Pool Suction Valves (HV-55-*F041, HV-55-*F042)
- HV-55-*F041 is normally closed (outboard).
- HV-55-*F042 is normally open (inboard).
- Receive open signals with:
- Low CST level (after 12 second time delay) (CST level at 2.25' indicated)
- OR -
- High Suppression Pool level (24'-1.5")
- Both valves receive close signal upon Div 2 isolation signal.
- Ensures supply of water to pump.

Front 37

Predict the HPCI system response to a loss of the following:
a. 125 VDC Bus B (Div 2 DC)

Back 37

a loss of Div 2 125/250 VDC power, the HPCI system is totally unavailable (without local manipulations and/or TPA's),

a. A loss of Div 2 125/250 VDC power, HPCI system response is as follows:
Point out relay K53B that provides:

HPCI Logic Power failure Bus B alarm light, and HPCI Out of Service annunciator
1) The armed and depressed manual initiation pushbutton is inoperative
2) Automatic HPCI initiation (low RPV level, high D/W pressure) is inoperative
3) High RPV water level trip and seal-in are inoperative
4) F041 and F042 valve position monitoring is inoperative, thus allowing the F004, F008, F011, and the F041/ F042 to be opened simultaneously
5) The auxiliary oil pump automatic control is inoperative. (The auxiliary oil pump may still be started using control switch S20)
6) Turbine trip control, both remote and automatic, are inoperative
a) The turbine may be tripped using the local hydraulic/ mechanical overspeed trip device. This action requires the trip device to be held in the tripped condition to prevent an automatic reset
Position monitoring prevents pump discharge valves (F006, F105) from opening.
7) F001 and STOP valve position monitoring are inoperative
8) F093, Vacuum Breaker Isolation Valve control is inoperative
9) Turbine supervisory alarms are inoperative
10) Flow controller control power is lost (Would result in a zero (0) demand signal to the control valve, thus closing the valve.)
11) Division 2 isolation logic, for both automatic and manual isolation, is inoperative.Individual valve controls may be used to isolate, as required.
12) Division 2 MO Valve Overload or Power Loss annunciation is inoperative.

Front 38

Predict the HPCI system response to a loss of the following:
b. 125 VDC Bus D (Div 4 DC)

Back 38

b. A loss of Div 4 125 VDC power, the HPCI system response is as follows:
1) HPCI Logic Power Failure Bus D alarm light, and HPCI Out of Service annunciator
Individual valve controls may be used to isolate, as required.
2) Division 4 automatic isolation is inoperative.
3) Vacuum breaker isolation valve (F095) control is inoperative.
4) Division 4 MO Valve Overload or Power Loss annunciation is inoperative.

a loss of Div 4125 VDC power allows both manual and automatic initiation with the major limitation being a lack of Division 4 isolation capability

Front 39

Predict the HPCI system response to a loss of the following:
c. AC power

Back 39

1) A loss of AC Power will prevent an isolation but will not prevent a system initiation. If an isolation becomes necessary, the Outboard Isolation Valve can be manually closed locally with the manual handwheel. Both Steamline Isolation Valves are AC powered
2) Also prevents closing Vacuum Bkr Isolation Valves. Both valves are outside containment and accessible

Front 40

Predict the HPCI system response to a loss of the following:
d. Keep full system

Back 40

1) With a total loss of the "Keep Full System", there is no assurance that the discharge piping is filled. An initiation could result in water hammer which has the potential for severe damage to the discharge piping

Front 41

Predict the HPCI system response to a loss of the following:
e. CST level

Back 41

1) A loss of CST Level would have no effect on HPCI operation provided the suction swapped to the Suppression Pool and Suppression Pool level is within limits

Front 42

Predict the HPCI system response to a loss of the following:
f. Suppression Pool level

Back 42

1) Suppression Pool Level
a) A loss of Suppression Pool level would have no effect on HPCI operation provided suction is from the CST and CST level is adequate. HPCI would however be Inop per Tech Specs
b) If, however, the HPCI system is aligned to the Suppression Pool (SP), a low SP level will result in insufficient NPSH to the ECCS and RCIC systems. IF SP level cannot be maintained above the level of the holes in the HPCI turbine discharge pipe (18’), operation of HPCI will directly pressurize containment. Therefore, HPCI, per T-102 is removed from service, regardless of adequate core cooling, if the consequences of its operation will jeopardize primary containment

Front 43

Predict the HPCI system response to a loss of the following:
g. Reactor pressure instruments

Back 43

1) Low reactor pressure is sensed by four (4) pressure transmitters
Objective #14g
2) Isolation logic and trip logic is actuated by a low pressure condition. Two (2) switches (trip units) must actuate to cause an inboard isolation, outboard isolation or a turbine trip
3) Failure of only one (1) pressure switch will neither cause nor prevent an isolation or turbine trip

Front 44

Predict the HPCI system response to a loss of the following:
h. Reactor level instruments

Back 44

f. Reactor Level Instruments
1) Reactor Water level is sensed by four (4) level transmitters
2) Four (4) level 8 trip units, arranged in a one-out-of-two-twice configuration, are required to initiate a turbine shutdown
3) Four (4) level 2 trip units, arranged in a one-out-of-two-twice configuration, are required to initiate HPCI
4) Failure of a single trip unit will neither cause nor prevent a HPCI initiation or turbine trip; however, failure of a single level leg (variable) low could cause a HPCI initiation. Failure of a single level leg high (or reference leg low) will not cause a turbine trip nor prevent a HPCI initiation

Front 45

HPCI highlights

Back 45

- Normally aligned to the CST. When CST tank level reaches low limit, suction source transfers to suppression pool (through *F041 and *F042 valves)
- Suction source swap occurs when CST level reaches 2'-3" –OR- when SP level is 24'-1.5"
- When will CST suction (*F004) open? HPCI initiation signal present and with *F041 not fully open.
(If *F041 is full open, then *F004 will not open automatically and cannot be opened manually)
- No Div II DC power = No HPCI
- HPCI power/oil pressure to run
- No single instrument failure will keep it from starting
- Operating steam pressure range: 200 – 1182 psig
- HPCI controls flow in AUTO and controls speed in MANUAL (controls turbine throttle valves)
- Two things seal in on HPCI
- White light (initiation signal)
- Aux oil pump seals in
- HPCI isolation button only works when there is a HPCI initiation signal present (white light lit)
- Upon a loss of Div II DC
- HPCI will not start if it is not running (DC oil pump will not start to supply oil pressure)
- HPCI will coast down if it is running (controller loses power)
- Concern with fire-induced spurious operation:
- Fire damage to a cable causes un-intended operation of a component (valve opens/closes,
equipment starts/stops, alarms, etc…)
- What power level will HPCI support during an ATWS: ~ 18.6%
- 5600 gpm ≈ 2.8 Mlb/hr. 2.8 Mlb/hr / 15 Mlb/hr = 18.67
- In the event of a spurious HPCI initiation and failure to trip, HPCI must be shut down at RSP within
4 minutes to prevent vessel overfill and flooding of the main steam lines.

Front 46

State the purpose of the High Pressure Coolant Injection (HPCI) System. (3)

Back 46

The HPCI System has the following functions:

- Provide coolant to reactor vessel following a Small Break LOCA until reactor vessel pressure is below the pressure at which CS and LPCI can maintain core cooling.

- Provide sufficient coolant to prevent the actuation of the ADS and maintain reactor level above the top of the reactor core in the event of a small pipe break 1 squr in or smaller.

- Additionally, the HPCI system may be used to maintain reactor water level and aid in pressure control during a reactor isolation.

Front 47

ECCS Design Basis (5)

Back 47

Prevent the following:
• Peak cladding temperature < 2200F
• Maximum cladding oxidation < 0.17 time the total cladding thickness before oxidation
• Maximum hydrogen generation < 0.01 times the hypotheitical max
• Coolable geometry
• Long-term cooling

Front 48

purpose and operation
Turbine Exhaust Rupture Diaphragms

Back 48

Two diaphragms in series located on turbine exhaust line designed to prevent damage to exhaust piping due to over pressure.

- Diaphragms will break on high exhaust pressure (>175 psig) and turbine exhaust will discharge to the HPCI room

- Pressure switch between diaphragms. Initiates HPCI Isolation on high turbine diaphragm exhaust pressure (PIS-*N655B, D, F, H, set at 10 psig)

Front 49

purpose and operation
Booster pump

Back 49

Single stage, Centrifugal pump, rated for 5670 gpm at 450 psig
- 5600 gpm for NPSH for main pump
- 70 gpm cooling water flow to lube oil cooler and barometric condenser

Driven by turbine via reduction gears - (Reduction ratio of 2:1, pump runs at 1/2 turbine speed)

Takes suction from CST (preferred source) Suppression Pool (T.S. and backup source)

Discharges to Main Pump suction

Front 50

purpose and operation
Barometric Condenser

Back 50

Collects drains from condesnate, steam, and non-condensable gasses.
Spargers spray water from Booster Pump discharge into steam volume to cool and condense steam
Non-condensibles drawn off by Vacuum Pump
Liquid removed by Condensate Pump

Front 51

purpose and operation
Vacuum pump

Back 51

1) Automatically starts on a system initiation, and maintains negative pressure in Barometric Condenser
2) Discharges to Reactor Enclosure Equipment Compartment Exhaust (REECE)

Front 52

purpose and operation
Exhaust Line Vacuum Breakers (HV-55-*F093 & HV-55-*F095)

Back 52

1) Normally open to prevent drawing water (which will cause water hammer on next HPCI start) from suppression pool into exhaust line after HPCI run.

2) Automatically close upon
a) High Drywell pressure 1.68 psig
AND
b) Low HPCI steam supply pressure 100 psig

3) HV-55-*F093 is powered from safeguard MCC D*24-R-G1, HV-55-*F095 is powered from safeguard MCC D*44-R-E.
a) Loss of AC will prevent an isolation but will not prevent a system initiation

Front 53

purpose and operation
HPCI lube oil

Back 53

Provides Turbine and Main pump with Hydraulic operating oil, Control oil, and Lubricating oil.

Front 54

purpose and operation
HPCI lube oil
DC Motor-Driven pump (Aux Oil Pump)

Back 54

1) Automatically starts with HPCI initiation
2) Provides oil during turbine start-up and shutdown (Automatically starts with decreasing pressure (about 1500-1200 turbine RPM))
3) Supplies oil at 85-90 psig for - Control Valve operation and Turbine lubrication
4) Motor Driven Pump automatically stops when Shaft Driven pump develops pressure
5) Driven by 250 VDC motor (Power from *DB-1)

Front 55

purpose and operation
HPCI lube oil
d. Shaft Driven pump

Back 55

1) Driven by low speed shaft and is connected by a worm gear arrangement
2) Supplies oil for normal operation
a) 105-110 psig
b) Developed at 1450-1650 RPM

Front 56

purpose and operation
HPCI lube oil
e. Lube oil cooler

Back 56

1) Cools oil from lube oil sump
2) Cooling water supplied by booster pump discharge

Front 57

purpose and operation
HPCI turbine

Back 57

a. Steam from “C” Main Steam Line is supplied to the HPCI turbine. Turbine exhaust steam is directed to the Suppression Pool
b. Steam flow (75,000-184,500 lbm/hr)
c. Steam pressure (200-1182 psig)
d. Exhaust pressure (25-65 psia)
e. HPCI speed (2150-4190 RPM) (Speed administratively maintained greater than 2200 rpm to minimize exhaust line oscillations)
f. Time from rest to rated speed less than 60 seconds

Front 58

Condensate Storage and Transfer System (CST) supports the operation of the HPCI

Back 58

1) A loss of CST Level would have no effect on HPCI operation provided the suction swapped to the Suppression Pool and Suppression Pool level is within limits
- CST is the preferred suction source for the HPCI pump
- Primary source of water to keep HPCI discharge piping full to ensure instantaneous injection and prevent water hammer on system start

Front 59

Suppression Pool supports the operation of the HPCI

Back 59

1) Suppression Pool Level
a) A loss of Suppression Pool level would have no effect on HPCI operation provided suction is from the CST and CST level is adequate. HPCI would however be Inop per Tech Specs
b) Low SP level will result in insufficient NPSH to the ECCS and RCIC systems.
IF SP level cannot be maintained above the HPCI turbine discharge pipe (18’), operation of HPCI will directly pressurize containment.

2) Suppression Pool Temperature / Pressure
a) An increase in SP temperature affects the NPSH and vortex limits of pumps taking suction on the SP. (Vortex limits are the lowest SP level above which air entrainment is not expected to occur to the pumps)
c) Elevated SP pressure will cause the HPCI turbine to trip earlier than expected due to increased backpressure on the turbine (140psig).
Reduced SP pressure will tend to reduce NPSH available to the pumps.

Front 60

Core Spray System supports the operation of the HPCI

Back 60

- ~45% of HPCI flow is fed to vessel via the "B" core spray loop

Front 61

Feedwater System supports the operation of the HPCI

Back 61

- ~55% of HPCI flow is fed to vessel via the "A" Feedwater line
- FW/CS injection split minimizes impact of HPCI ops during ATWS event; minimizes thermal peaking in bundles adjacent to stuck rods.

Front 62

Main Steam System supports the operation of the HPCI

Back 62

- Steam from “C” Main Steam Line is supplied to the HPCI turbine.

Front 63

DC Distribution System supports the operation of the HPCI

Back 63

- DC lube oil pump driven by 250 VDC motor

Front 64

AC Distribution System supports the operation of the HPCI

Back 64

1) A loss of AC Power will prevent an isolation but will not prevent a system initiation. If an isolation becomes necessary, the Outboard Isolation Valve can be manually closed locally with the manual handwheel. Both Steamline Isolation Valves are AC powered
2) Also prevents closing Vacuum Bkr Isolation Valves. Both valves are outside containment and accessible

Front 65

Liquid Rad Waste System supports the operation of the HPCI
- Condensate drains to Radwaste (HV-55-*F025 & HV-55-*F026)

Back 65

AOVs
- *F025
- Normally open.
- Automatically shuts if Turbine Steam Supply *F001 is not fully shut.
- If closed, valve will not open unless *F001 is fully shut.

- *F026
- Normally closed.
- Opens and closes on vacuum tank high and low level respectively
- Automatically closes if Turbine Steam Supply Valve *F001 is not fully shut

Front 66

HPCI Minimum Flow Valve (HV-55-*F012) Interlocks

Back 66

Normally Closed; opens to provides minimum flow protection to pump and prevents inadvertent draining of CST to the Suppression Pool

OPEN signal if
- System flow is low AND sufficient pump discharge pressure
- Opens at <550 gpm AND greater than 125 psig

CLOSED signal if either:
- Sufficient system flow (650 gpm), or
- Turbine Steam Supply (*F001) fully shuts, or
- Turbine stop valve (FV-*12) fully shuts

Front 67

Identify the conditions, including setpoints that will cause a HPCI automatic initiation.

Back 67

- RPV low water level (-38”) OR
- High drywell pressure, (1.68 psig) OR
- Manual (arm and depressed pushbutton for ~13 seconds to fully initiate HPCI)
(13 seconds allows time for injection valves (*F006 and *F105 to receive open signals))

Front 68

Identify the sequence of events that occur when a HPCI system automatic initiation signal is received.

Back 68

- HV-55-*F001, HPCI Turbine Steam Supply Valve opens (ONLY IF exhaust valve is open)
- Motor Driven Auxiliary Oil Pump starts
- Barometric Condenser Vacuum Pump starts
- Once the Auxiliary Oil Pump is delivering sufficient oil pressure:
- TSV and Governor Control Valve open (controlled by ramp generator)
- When TSV and 001 Valve not fully closed, HV-55-*F006, HPCI Pump Discharge to Core Spray, and the HV-55-*F105, HPCI Pump Discharge to Feedwater, valves open
- CST suction (004) gets an open signal; test return valves (008, 011 and 071) get closed signal.

Front 69

Identify the requirements for resetting a HPCI system automatic initiation.

Back 69

- The method HPCI system is shutdown is determined by if the initiation signal can be reset

- If the initiation signal is no longer present, (white seal-in light can be reset)
- Simultaneously depress turbine trip PB and close Steam Supply Valve *F001

- If initiation signal is present (white seal-in light cannot be reset)
- Ensure Barometric Condenser Vacuum Pump and Aux Oil Pump are running
- Depress the Manual Isolation Pushbutton
- OR -
- Place HPCI flow controller in manual and lower speed (above 2200 rpm) such that HPCI is no longer injecting

Front 70

a.          Identify the conditions, including setpoints, that will cause a HPCI system automatic isolation.

Back 70

1) The automatic HPCI system isolation logic is divided into two logic systems, and actuates upon receiving any of the following:

DIVISION II or DIV IV
a) Low steam supply pressure - 100 psig
b) High steam line flow - 974" wc with a 3 second time delay
c) High temperatures - Requires NORMAL/BYPASS switch to be in NORMAL
(1) Equipment area DT - 104°F
(2) Equipment area - 225°F
(3) Steam supply piping area - 175°F
d) Turbine diaphragm exhaust pressure high - 10 psig

DIVISION II ONLY
e) Manual - Pushbutton depressed (S32) with an initiation signal present

Front 71

b.          Identify the sequence of events that occur when a HPCI system automatic isolation signal is received.

Back 71

Div. 2 Isolation Signal:
1) The following HPCI system valves close:
a) HV-55-*F003, HPCI Steam Line Outboard Isolation
b) HV-55-*F041 and HV-55-*F042 HPCI Pump Suction Valves from the Suppression Pool
c) HV-55-*F100, HPCI Steam Line Warmup Bypass
2) The HPCI Turbine receives an automatic trip signal

Div. 4 Isolation Signal:
1) HV-55-*F002, HPCI Steam Line Inboard Isolation Valve, auto closes
2) The HPCI Turbine receives an automatic trip signal
T-LOT-0340-5 for the resetting of a system isolation using:

Front 72

c.          Identify the requirements for resetting a HPCI system automatic isolation.

Back 72

The isolation can be reset when:
1) Reactor pressure is greater than 100 psig,
AND
2) The cause of the system isolation has been determined and corrected.

3) The associated handswitch for the isolated valve is placed in the closed position prior to resetting (not an interlock).
4) Repressurize slowly using the HPCI steam line warmup bypass (HV-55-*F100) to minimize thermal shock.

Front 73

a.          Identify the conditions, including setpoints, that will initiate an automatic HPCI turbine trip.

Back 73

4. AUTOMATIC TRIPS

a. The HPCI turbine will automatically trip upon receiving any of the following signals:

1) High turbine exhaust pressure 140 psig
2) Low pump suction pressure 15" Hg vacuum
3) High reactor level +54" (wide range) (will seal in and reqiures operator to depress the reset switch)
a) +54" RPV water level will cause excessive moisture carry-over and turbine damage may result
b) OT-110, Reactor High Level, directs both isolation valves (*F002 and *F003) closed to protect down stream piping and turbine blading due to an overfilling event from low pressure systems (directed at +100" AND level rise cannot be controlled)
4) Low steam supply pressure - 100 psig
5) Div-2 isolation
6) Div-4 isolation
7) Manual trip
8) Manual shutdown from RSP (NOT A TURBINE TRIP) Control Valves closes due to removal of DIV II control power

b. In addition, to the above listed automatic trips, the HPCI Turbine will auto trip on an overspeed condition, as outlined below:
HPCI overspeed automatically resets as speed is reduced
1) At a predetermined RPM, a pin type mechanical emergency trip weight is displaced by centrifugal force (125% or 5238 rpm)
2) The pin strikes a ball tappet assembly, lifting the tappet and a connected hydraulic trip piston upwards, overcoming the reset spring force of the piston
3) With the piston raised, internal ports are uncovered, dumping control oil, causing the TSV to close
4) Once turbine speed is reduced for a predetermined time (3-6 sec), the trip will automatically reset (via realignment of ports) allowing a restart of the turbine

Front 74

b.          Identify the sequence of events that occur following a HPCI system automatic trip signal.

Back 74

c. The following events occur upon receiving a HPCI Turbine Trip signal
1) The Turbine Trip Auxiliary Relay, K37, is energized which energizes solenoid valve SV1. With SV1 energized, control oil is dumped, depressurizing the control oil lines, allowing spring pressure to close the TSV, isolating steam to the turbine (With the TSV full closed, HPCI Pump Discharge Valves F006 and F105 and Minimum Flow Valve F012 receive auto close signals)

Front 75

c.          Identify the requirements for resetting an automatic trip.

Back 75

d. S55.1.C, Recovery from HPCI Turbine Trip, the trip can be reset when:
1) The cause of the turbine trip has been determined and corrected,
AND

2) The isolation has been reset per S55.1.B, Recovery from System Isolation, if applicable.
3) If the HPCI System was initiated by an automatic initiation and was shutdown by a RPV high level signal (FV-56-112 closed and RPV high level light lit) then HPCI will only restart on subsequent low RPV level initiation.
4) The RPV high level signal (+54”) must be manually reset to allow HPCI to auto start on high drywell pressure or a manual initiation

Front 76

methods used to prevent water hammer in:
a. HPCI turbine exhaust line

Back 76

- Vacuum Breakers (HV-55-*F093 & HV-55-*F095) prevent drawing water from suppression pool into exhaust line after HPCI run. Minimizing water in the HPCI exhaust line will prevent water hammer on the next HPCI start

Front 77

methods used to prevent water hammer in:
b. HPCI pump discharge line.

Back 77

- The CONDENSATE STORAGE and TRANSFER SYSTEM, backed up by the KEEP FILL SYSTEM provides a source of water to keep HPCI discharge piping full to ensure instantaneous injection and prevent water hammer on system star

Front 78

Predict the operation of the HPCI turbine ramp generator during an automatic or manual HPCI system start.

Back 78

- The ramp generator overrides the flow controller during turbine startup to allow a controlled rate of acceleration. Once the ramp generator output exceeds the signal from the flow controller, the controller takes over and maintains control until the ramp generator is reset. The ramp generator is reset whenever the turbine stop valve is fully closed

Front 79

Predict the sequence of events that occur during a HPCI system manual initiation.

Back 79

a. In addition to the automatic HPCI system initiation signals, the HPCI system may be manually initiated (arm and depress PBs) under the following condition:
1) When directed by the TRIP procedures to maintain RPV level or pressure

b. The HPCI system may also be manually initiated by S55.1.D, HPCI System Full Flow Functional Test, by performing the following:
1) Start the Barometric Condenser Vacuum Pump
2) Opening the HV-55-*F011, HPCI/RCIC Test Return to the CST Header
3) Perform either a Manual Slow Start or a Manual Quick Start, as follows:
a) Per S55.1.D, severe exhaust line oscillations may develop
b) Manufacturer's concerns that at lower speeds, adequate water flow may not exist to provide required lube oil cooling or condensate spray for steam condensing in the Barometric Condenser

a) For a Manual Slow Start:
(1) Place the flow controller in manual and reducing the output signal to 0
(2) Open the HPCI Turbine Steam Supply Valve, HV-55-*F001
(3) Start the Auxiliary Oil Pump and observe the TSV open
(4) Verify cooling water valve opens
(5) Slowly raising the flow controller output to greater than 2200 RPM.
(6) Immediately throttle open the HV-55-*F008, HPCI Test Loop shutoff as soon as speed is observed.

b) For a Manual Quick Start:
(1) With the flow controller in auto and set at 5600 gpm, simultaneously opening the HPCI Turbine Steam Supply Valve, HV-55-*F001, and start the Auxiliary Oil Pump.
(2) Immediately throttle open the HV-55-*F008, HPCI Test Loop shutoff as soon as speed is observed

c. HPCI may be used for level control and/or pressure control. To transfer HPCI from pressure control mode to injection mode or from injection mode to full flow test then operations should be performed in accordance with S55.7.A, Transfer of HPCI from Pressure Control Mode to Injection Mode and Back

d. Once the HPCI system is no longer required to aid in maintaining RPV level and/or pressure control, or the full flow test is complete, the HPCI system may be shutdown by manually tripping the turbine, holding the "Turbine Trip" pushbutton depressed, while simultaneously closing the HPCI Turbine Steam Supply Valve, HV-55-*F001

Front 80

Identify the method of turbine speed control and pump flow control during HPCI operation.

Back 80

- Speed Control (MANUAL): In MANUAL, THE flow controller will operate THE governor In an isochronous mode, throttling THE Control valve to maintain Speed constant
- flow Control (AUTO): In AUTO, THE flow controller receives an input from pump flow and compares THE flow SIGNAL with A flow setpoint. If actual flow is less than THE setpoint, THE governor will send A SIGNAL to THE Control valve to throttle open until they agree

Front 81

c. HPCI system
- Suppression Pool Suction Valves (HV-55-*F041, HV-55-*F042)

Back 81

- Suppression Pool Suction Valves (HV-55-*F041, HV-55-*F042)
- HV-55-*F041 is normally closed (outboard).
- HV-55-*F042 is normally open (inboard).
- Receive open signals with:
- Low CST level (after 12 second time delay) (CST level at 2.25' indicated)
- OR -
- High Suppression Pool level (24'-1.5")
- Both valves receive close signal upon Div 2 isolation signal.
- Ensures supply of water to pump.

Front 82

Predict the HPCI system response to a loss of the following:
a. 125 VDC Bus B (Div 2 DC)

Back 82

a loss of Div 2 125/250 VDC power, the HPCI system is totally unavailable (without local manipulations and/or TPA's),

a. A loss of Div 2 125/250 VDC power, HPCI system response is as follows:
Point out relay K53B that provides:

HPCI Logic Power failure Bus B alarm light, and HPCI Out of Service annunciator
1) The armed and depressed manual initiation pushbutton is inoperative
2) Automatic HPCI initiation (low RPV level, high D/W pressure) is inoperative
3) High RPV water level trip and seal-in are inoperative
4) F041 and F042 valve position monitoring is inoperative, thus allowing the F004, F008, F011, and the F041/ F042 to be opened simultaneously
5) The auxiliary oil pump automatic control is inoperative. (The auxiliary oil pump may still be started using control switch S20)
6) Turbine trip control, both remote and automatic, are inoperative
a) The turbine may be tripped using the local hydraulic/ mechanical overspeed trip device. This action requires the trip device to be held in the tripped condition to prevent an automatic reset
Position monitoring prevents pump discharge valves (F006, F105) from opening.
7) F001 and STOP valve position monitoring are inoperative
8) F093, Vacuum Breaker Isolation Valve control is inoperative
9) Turbine supervisory alarms are inoperative
10) Flow controller control power is lost (Would result in a zero (0) demand signal to the control valve, thus closing the valve.)
11) Division 2 isolation logic, for both automatic and manual isolation, is inoperative.Individual valve controls may be used to isolate, as required.
12) Division 2 MO Valve Overload or Power Loss annunciation is inoperative.

Front 83

Predict the HPCI system response to a loss of the following:
b. 125 VDC Bus D (Div 4 DC)

Back 83

b. A loss of Div 4 125 VDC power, the HPCI system response is as follows:
1) HPCI Logic Power Failure Bus D alarm light, and HPCI Out of Service annunciator
Individual valve controls may be used to isolate, as required.
2) Division 4 automatic isolation is inoperative.
3) Vacuum breaker isolation valve (F095) control is inoperative.
4) Division 4 MO Valve Overload or Power Loss annunciation is inoperative.

a loss of Div 4125 VDC power allows both manual and automatic initiation with the major limitation being a lack of Division 4 isolation capability

Front 84

Predict the HPCI system response to a loss of the following:
c. AC power

Back 84

1) A loss of AC Power will prevent an isolation but will not prevent a system initiation. If an isolation becomes necessary, the Outboard Isolation Valve can be manually closed locally with the manual handwheel. Both Steamline Isolation Valves are AC powered
2) Also prevents closing Vacuum Bkr Isolation Valves. Both valves are outside containment and accessible

Front 85

Predict the HPCI system response to a loss of the following:
d. Keep full system

Back 85

1) With a total loss of the "Keep Full System", there is no assurance that the discharge piping is filled. An initiation could result in water hammer which has the potential for severe damage to the discharge piping

Front 86

Predict the HPCI system response to a loss of the following:
e. CST level

Back 86

1) A loss of CST Level would have no effect on HPCI operation provided the suction swapped to the Suppression Pool and Suppression Pool level is within limits

Front 87

Predict the HPCI system response to a loss of the following:
f. Suppression Pool level

Back 87

1) Suppression Pool Level
a) A loss of Suppression Pool level would have no effect on HPCI operation provided suction is from the CST and CST level is adequate. HPCI would however be Inop per Tech Specs
b) If, however, the HPCI system is aligned to the Suppression Pool (SP), a low SP level will result in insufficient NPSH to the ECCS and RCIC systems. IF SP level cannot be maintained above the level of the holes in the HPCI turbine discharge pipe (18’), operation of HPCI will directly pressurize containment. Therefore, HPCI, per T-102 is removed from service, regardless of adequate core cooling, if the consequences of its operation will jeopardize primary containment

Front 88

Predict the HPCI system response to a loss of the following:
g. Reactor pressure instruments

Back 88

1) Low reactor pressure is sensed by four (4) pressure transmitters
Objective #14g
2) Isolation logic and trip logic is actuated by a low pressure condition. Two (2) switches (trip units) must actuate to cause an inboard isolation, outboard isolation or a turbine trip
3) Failure of only one (1) pressure switch will neither cause nor prevent an isolation or turbine trip

Front 89

Predict the HPCI system response to a loss of the following:
h. Reactor level instruments

Back 89

f. Reactor Level Instruments
1) Reactor Water level is sensed by four (4) level transmitters
2) Four (4) level 8 trip units, arranged in a one-out-of-two-twice configuration, are required to initiate a turbine shutdown
3) Four (4) level 2 trip units, arranged in a one-out-of-two-twice configuration, are required to initiate HPCI
4) Failure of a single trip unit will neither cause nor prevent a HPCI initiation or turbine trip; however, failure of a single level leg (variable) low could cause a HPCI initiation. Failure of a single level leg high (or reference leg low) will not cause a turbine trip nor prevent a HPCI initiation

Front 90

HPCI highlights

Back 90

- Normally aligned to the CST. When CST tank level reaches low limit, suction source transfers to suppression pool (through *F041 and *F042 valves)
- Suction source swap occurs when CST level reaches 2'-3" –OR- when SP level is 24'-1.5"
- When will CST suction (*F004) open? HPCI initiation signal present and with *F041 not fully open.
(If *F041 is full open, then *F004 will not open automatically and cannot be opened manually)
- No Div II DC power = No HPCI
- HPCI power/oil pressure to run
- No single instrument failure will keep it from starting
- Operating steam pressure range: 200 – 1182 psig
- HPCI controls flow in AUTO and controls speed in MANUAL (controls turbine throttle valves)
- Two things seal in on HPCI
- White light (initiation signal)
- Aux oil pump seals in
- HPCI isolation button only works when there is a HPCI initiation signal present (white light lit)
- Upon a loss of Div II DC
- HPCI will not start if it is not running (DC oil pump will not start to supply oil pressure)
- HPCI will coast down if it is running (controller loses power)
- Concern with fire-induced spurious operation:
- Fire damage to a cable causes un-intended operation of a component (valve opens/closes,
equipment starts/stops, alarms, etc…)
- What power level will HPCI support during an ATWS: ~ 18.6%
- 5600 gpm ≈ 2.8 Mlb/hr. 2.8 Mlb/hr / 15 Mlb/hr = 18.67
- In the event of a spurious HPCI initiation and failure to trip, HPCI must be shut down at RSP within
4 minutes to prevent vessel overfill and flooding of the main steam lines.