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29 Cards in this Set
- Front
- Back
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ATWS Recirc Pump Trips
2 |
* Rx High Pressure of 1149
OR * RX Low Level, -38 inches with a 9 second time delay (seals in) |
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EOC - RPT Trips
that trip both A and B RPT Breakers (3) |
- Reactor Power > 30% (1st Stage Shell
Pressure greater then 188/167) AND either: - TSVs < 95% OPEN, OR - TCVs RETS Pressure < 500 psig |
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Recirc MG Set Scoop Tube Locks
10 |
- *1(2) Unit Auxiliary Bus Undervoltage
- Low lube oil pressure (auxiliary lube oil pump *A(B)1 or *A(B)2) - Speed Control Circuit Control Signal Failure - Loss of AC Auxiliary Circuit Control Power - Scoop Tube Positioner Power Switch in "OFF" position - Loss of Lockout Bus 125 VDC Control Power - Scoop Tube Brake control switch taken to "TRIP" position - Scoop Tube Positioner motor thermal overload - High Speed or Low Speed electrical stop - Loss of AC power to Scoop Tube Positioner |
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Recirc MG Set Drive Motor Breaker Trips
9 |
- Recirc MG Set control switch taken to "STOP" position
- Low lube oil pressure to Fluid Coupler bearings (< 30 psig for > 6.0 seconds) - Recirc MG Set Drive Motor bus undervoltage - Recirc Pump suction valve < 90% OPEN - Recirc Pump discharge valve not fully OPEN (3-minute time delay for startup) - Recirc MG Set Generator lockout - Recirc MG Set Drive Motor lockout - Main Unit lockout (if 13.2 Unit Auxiliary Bus *1(*2) being powered from unit) - Loss of Stator Cooling Water (if total FW flow is > 6.7 Mlb/hr) *A" Recirc Pump trips after 9-second time delay "*B" Recirc Pump trips after 18-second time delay |
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Recirc MG Set Generator Lockouts
7 |
- Incomplete Start Sequence (Recirc MG Set Generator Field Breaker not CLOSED within 22 seconds of Drive Motor Breaker closing)
- Recirc Pump Motor instantaneous differential overcurrent - Recirc MG Set Generator neutral overvoltage - Recirc MG Set Generator overcurrent - Recirc MG Set Exciter field overcurrent - Recirc MG Set Exciter field undervoltage - Recirc MG Set Drive Motor lockout |
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Recirc MG Set Drive Motor Lockouts
4 |
- Phase overcurrent
- Phase current unbalance - Ground fault - Differential overcurrent |
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Recirc MG Set Start Sequence
T = 0 |
Drive Motor Breaker CLOSES, Pump Start Sequence timer relay (K18A(B)) energizes, Generator Instantaneous Overcurrent trip replaced with Timed Overcurrent trip (10 second delay)
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Recirc MG Set Start Sequence
T = 12 |
Excitation Transfer Relay (K17A(B)) energizes and Recirc MG Set Exciter field flashed from 120 VAC Distribution Panel *0Y109 (*0Y110) through Voltage Regulator
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Recirc MG Set Start Sequence
T = 13 |
Field Application And Undervoltage Relay (K12A(B)) energizes and Generator Field Breaker CLOSES, input to Scoop Tube Positioner controller switches from Startup Signal Generator to Manual Control Station via Speed Limiter Network (speed demand) and Tachometer Generator (actual speed). In addition, "Loss Of Generator Field" trip of Drive Motor Breaker is inhibited
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Recirc MG Set Start Sequence
T = 15 |
Generator Timed Overcurrent trip replaced with Instantaneous Overcurrent trip, Pump Start Sequence timer relay (K18A(B)) de-energizes. In addition, Recirc MG Set Exciter field source is switched from 120 VAC Distribution Panel *0Y109 (*0Y110) to output of Generator through Voltage Regulator
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Recirc MG Set Start Sequence
T = 16 |
"Loss Of Generator Field" trip of Drive Motor Breaker is re- enabled
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Recirc MG Set Start Sequence
T = 22 |
if Generator Field Breaker is not CLOSED, Incomplete Startup Sequence relay (K27A(B)) will energize, resulting in energization of Generator Lockout Relay (K3A(B)), and trip of Drive Motor and Generator Field Breakers
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Recirc MG Set Starting Interlocks (11)
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- Recirc MG Set Drive Motor Breaker RACKED IN
- Two Turbine Enclosure Exhaust Fans running (can be defeated with SSV permission) - Recirc Pump suction valve fully OPEN - Recirc Pump discharge valve fully CLOSED - Both RPT Breakers RACKED IN and CLOSED - Unit Protection Lockout Relays reset (13.2 KV Unit Auxiliary Bus *1(2)) - Sufficient Recirc MG Set lube oil pressure ( > 20 psig) (Breaker at *D01 must be RACKED IN and CLOSED) - Recirc MG Set Generator Lockout Relay reset - Recirc MG Set Generator Field Breaker OPEN - Recirc MG Set Drive Motor Lockout Relay reset - Recirc MG Set Scoop Tube positioned at 35% to 45% (Startup Signal Generator setting) |
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Recic
28% Speed Runback |
- Total Feedwater (FW) flow < 2.8 mlb/hr for > 15 seconds, (to ensure NPSH for Recirc pumps and jet pumps by ensuring suffiicient subcooling of the downcomer water by the incoming FW
OR - RPV level < 12.5 inches, (anticipates RPS scram and aids in reactor power reduction) OR - Recirc Pump discharge valve not fully open (protect recirc pump from overheating) |
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Recirc
42% Speed Runback |
- RPV level < 27.5 inches AND any individual RFP flow < 0.94 Mlb/hr (reduces power to restore RPV level by reducing steam flow)
OR - Total FW flow > 12.0 Mlb/hr AND < 3 Condensate Pump breakers closed (attemps to prevent RPT trip on low suction pressure) |
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Thermal Stratification Restrictions
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coolant temperature difference between RPV steam dome and RPV bottom head drains exceed 145F:
The Recirc pumps shall not be started, power shall not be raised Recirc flow shall not be raised Basis: prevent rapid temperature increases for RPV below core components |
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If the running AC Lube Oil Pump fails, the standby AC Lube Oil Pump will automatically start if
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The other AC Lube Oil Pump is de-energized
AND Control switch is in "AUTO" AND Lube oil pressure drops to 30 psig (lowering) AND The associated Recirc MG Set Drive Motor breaker is racked into the "CONNECTED" position and is closed. |
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If both AC Lube Oil Pumps fail, the DC Lube Oil Pump will automatically start if:
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Control switch is in "AUTO"
AND lube oil pressure has dropped below 20 psig AND lube oil pressure has been 30 psig for 6.0 seconds OR Control switch is in "AUTO" AND lube oil pressure drops to 10 psig (lowering) instantaneously. |
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Failure of RRP seal #1
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Indications of a failure of seal #1
Seal Cavity #1 pressure: 1000 psig Seal Cavity #2 pressure: rises to: 1000 psig Seal staging line flow rises RECIRC PUMP SEAL STAGE HI/LO FLOW alarm ( 0.9 gpm) |
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Failure of RRP seal #2
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Indications of a failure of Seal #2
Seal Cavity #1 pressure: 1000 psig Seal Cavity #2 pressure: drops below 500 psig, to a lower pressure dependent on the severity of the seal failure. RECIRC PUMP SEAL STAGE HI/LO FLOW alarm ( 0.5 gpm) RECIRC PUMP SEAL LEAKAGE HI FLOW alarm ( 0.1 gpm) |
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Failure of both RRP seals
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Indications of a failure of both seals
Seal Cavity #1 and Seal Cavity #2 pressures are approximately equal, and lower than normal. RECIRC PUMP SEAL STAGE HI/LO FLOW alarm RECIRC PUMP SEAL LEAKAGE HI FLOW alarm |
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To OPEN the Seal Purge Valves:
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Its control switch must be in "AUTO"
AND Recirc Pump Suction Valve must be off it's closed seat AND One Recirc Pump Drive Motor breaker must be closed |
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The Seal Purge Valves will CLOSE if:
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Its control switch is placed in "CLOSE"
OR Its associated Recirc Pump Suction Valve is fully closed OR Both Recirc Pump Drive Motor breakers OPEN (3-min time delay) |
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The Seal Purge Valves fail CLOSED on:
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Loss of instrument air
OR Loss of power to the solenoid powered air supply valve |
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During operation with only one Recirc loop
Flow through the idle Jet Pumps is subtracted from the operating Recirc loop if: |
- If one discharge valve is 90% open affected Recirc loop’s Jet Pump flow from the unaffected Recirc loop’s Jet Pump flow.
- If a Recirc Pump trips (MG Set Field Breaker opens), flow from that Recirc Pump is subtracted. |
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During normal operation with two Recirc loops
All flow through the Jet Pumps flows through the reactor core. |
- Recirc Loop flows are added if both Recirc Pumps are running with discharge valves fully open, or if both Recirc Pump discharge valves are fully closed (both Recirc Pumps secured).
- Summing circuit add both Recirc loop flows if both Recirc loops are removed from service. |
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Suction Isolation Valve Interlocks
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Suction Isolation Valve Interlocks
Must be full OPEN for MG Set start (close Drive Motor breaker). 90% open - trips Drive Motor breaker. Full CLOSED will send CLOSE signal to Seal Purge Valves when control switch is in "AUTO." |
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Discharge Isolation Valve Interlocks
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Discharge Isolation Valve Interlocks
Must be full CLOSED for MG Set start (close the Drive Motor breaker). Not full OPEN initiates a 28% speed runback & Drive Motor Breaker (3-minute time delay for startup). One valve 90% OPEN - subtract recirc loop flow from other loop flow. |
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Normal Seal Pressure and Seal purge Flow
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Normal seal pressures:
Seal 1 cavity – at reactor pressure (~1000psig) Seal 2 cavity – 1/2 reactor pressure (~500psig) Normal seal purge flow CRD to Seal Cavity 1 – 1.5 gpm Seal Cavity 1 to pump flow – 0.75 gpm Seal Cavity 1 to Seal Cavity 2 – 0.75 gpm Seal Cavity 2 to DEDT ("seal staging" flow) – 0.75 gpm |
