Zach Stubby's Heavy Hitters - Secondary Systems Part 2 Flashcards

Question

When activated either generator lockout relay (86-1/1G or 86-2/1G) will initiate the following:

Answer 1

→Turbine trip →opens Generator output breakers 8000/8010 (U1) or 8020/8030 (U2) →Exciter Field Breaker opens →trips non-safeguards normal supply breakers to 6.9 kV from UTs →stops MT cooling →stops UT cooling →stops Isophase Bus Duct cooling →enables transformer fire protection deluge valves

Answer 2

The following events will initiate a generator lockout: **1. Total loss of field** 2. 345 KV system voltage less than 85% in conjunction with a total loss of field 3. Field ground 4. Pilot exciter short **5. Generator phase differential** 6. Stator ground **7. Distance protection/ Main transformer ground: the distance protection or a ground on either main transformer has a 1.4 second time delay; trips make up step 2 in the ground fault protection scheme** 8. Main transformer sudden pressure 9. Unit auxiliary transformer phase differential 10. Primary trip signal for generator output breaker 8000 or 8010 (8020 or 8030) 11. Volts per hertz **12. Generator-transformer phase differential** 13. Unit auxiliary transformer sudden pressure 14. Unit auxiliary transformer over current 15. Backup trip signal for generator output breaker 8000 or 8010 (8020 or 8030) **16. Generator negative sequence** 12% 17. Generator terminal box water level high or PW Head Tank Level <78%; coincident with a reverse power

Answer 3

→1 in service, 1 in standby →79 gpm PDP →Pump A powered from uB3-1 →Pump B powered from uB4-1 →normal seal oil pressure maintained at 12-15 psid →standby pump auto starts on low system pressure of 10 psid

Answer 4

→powered by uD2-2 →auto starts on low system pressure of 5 psid →if no seal oil pumps can be started within an hour, shut down the unit and reduce H2 pressure to 2 psig (per ABN-402) →recirc solenoid valves auto close on loss of seal oil pressure (<1.5 psid) to prevent H2 leakage

Answer 5

→provided to permit continued operation in the event of a cooler failure →louvers in the hot (lower compartment) and cold (exciter enclosure) air compartments are automatically opened by actuators admitting air from outside the exciter enclosure and discharging the hot air through openings below the coolers. →Setpoint: 122°F

Answer 6

→Pilot Exciter: permanent magnets send AC to TVR →TVR sends variable DC to Main Exciter stator →Main Exciter Stator sends AC to Main Exciter Rotor →Main Exciter Rotor sends AC to to Rectifier Wheels →Rectifier Wheels send DC to Main Generator Rotor (a.k.a. field winding) →Rotor rotation feeds AC to Main Generator Stator →Main Generator Stator feeds AC to electrical system grid

Answer 7

When Instrument Air is not in use, it is physically disconnected, so there is no flow path into the generator.

Answer 8

→ALB-6D Win 1.9 "ANY TURB RUNBACK EFFECTIVE" will be lit →will not be lit if already below runback power setpoint →for auto runbacks, the annunciator on Digital Control System (DCS) is illuminated for **9 minutes**

Answer 9

→HDP Trip: 35% per min to 800 MW (70%) →MFP or Condensate Pump Trip: 35% per min to 700 MW (60%) →C3 / C4: 200% per min for 1½ sec, then off for 28½ sec; repeat until condition clears

Answer 10

→preset buttons available to drive turbine to selected MW load →button provided for 50 MW @ 100 MW/Min; resets in 30 sec →load settings available: 900 and 700 MW at 35% per min →must be manually reset on DCS by turning OFF sub loop controller →for manual runback or load reduction, Runback Annunciator clears once actual load reaches load setpoint

Answer 11

Turning Gear is supplied from 2 valves: →requires both valves to be open to initially roll the turbine →speed varies between 80 and 190 rpm dependent upon whether vacuum established →auto close if thrust bearing LO pressure 25# →alarm actuated if EITHER valve is open AND <9 rpm on main turbine →neither valve will open if generator breakers are closed u-HV-6554A Turning Gear Valve #1: →auto opens at 230 rpm decreasing →auto closes at 260 rpm increasing →manually operated <50 rpm due to lack on fine control at low speed u-HV-6554B Turning Gear Valve #2: →used to initially roll the turbine →auto closes at 15 rpm increasing →can be manually opened <15 rpm

Answer 12

→solenoid valve opens at 194°F with >1340 rpm →sprays condensate into the area to lower temps →happens mostly at low power with low steam flow available to cool area →condensate line taps off header before drain coolers →solenoid valve must be manually closed once temp restored, but will auto close when high temp clears if LP turbine inlet steam pressure ≥7 psia →separate MOV provided if solenoid valve insufficient to maintain temps →if exhaust temp can't be maintained <212°F, turbine is manually tripped

Answer 13

→3 pumps, A, B, & C →powered from uB1, uB2, uB3 →A and B auto start at 110 psig →C auto starts at 103 psig →during normal startup, Aux Lube Oil Pumps can be shut off around 1700 rpm because Main Oil Pump will have developed enough pressure

Answer 14

→powered from uD2 →auto starts at 32 psig bearing header pressure →only supplies bearings

Answer 15

→auto starts at 510 rpm decreasing →auto stops at 540 rpm increasing

Answer 16

→located in HP turbine front pedestal →driven by gear attached to HP turbine shaft →provides all the lubrication needs of the Main Turbine / Main Generator once turbine reaches 1800 rpm →during normal startup, Aux Lube Oil Pumps can be shut off around 1700 rpm because Main Oil Pump will have developed enough pressure

Answer 17

→initially supplied from Aux Steam; as turbine power increases, turbine becomes self-sealing at ≈40% turbine power →Gland Steam supply header maintained at 4” WC via AOVs (supply and leakoff); valves fail as is on loss of air or power →leakoff directed to FW Heaters 5 and 6 →leakoff header from Gland Seals and leakoff from stop and control valves is directed to Gland Steam Condenser →Gland Steam exhaust uGS-0141, 0142 vented to PPV to ensure monitoring if SG tube leak →opening the emergency bypass to atmosphere on either the Main or Auxiliary Gland Steam Condenser will result in an unmonitored release to atmosphere

Answer 18

→3 dual stage pumps; stage 1 (LP) 114 psig, stage 2 & 3 (HP) 455 psig →normally 2 pumps in service; standby pump auto starts at 398 discharge pressure →powered from uB1, uB2, uB4 →red handswitches on CB-09 →114 psig control fluid supplies: →Main Turbine Control →tripping (protection) →HP Stop Valve actuators →455 psig control fluid supplies: →LP Stop Valve actuators →HP/LP Control Valves

Answer 19

→EHC fluid maintained at 131°F ± 9°F to maintain constant viscosity for proper operation of turbine valves →minimum 70°F for starting EHC pumps →Fyrquel is used because of its high flashpoint (475°F)

Answer 20

→114 psig fluid directed to Startup Fluid Solenoids, Trip Block Valve and EHC Converter →used to control the overall hydraulic system.

Answer 21

→114 psig fluid supplied from the Startup Fluid Solenoids and directed to Test Valves, which are used to stroke test stop and control valves →essentially used to reset the system for power operation.

Answer 22

→114 psig fluid supplied from the Trip Block Valve and directed to the EHC Converter, Test Valves, Reset Valve, Trip Test Valves and HP/LP Stop Valves →used to open the HP stop valves and is the source for Secondary Fluid. →Trip Fluid also ports 445 psig fluid to open the LP Stop valves

Answer 23

→114 psig fluid coming from the EHC Converter and supplied to HP and LP Control Valves →used to control the HP and LP Control Valves by porting 455 psig fluid to actually operate the valves

Answer 24

→designed to prevent overspeed of turbine in event of load rejection →initiated by: →any power level, load rejection >290MWe per second →lower loads, IF actual load drops below 160MWe, AND actual load is 160 Mwe lower than load target →when circuit initiated, EHC will transfer from load control to speed control →speed control setpoint automatically set to value ≈ current actual load →reset C-7 as required once desired load is reached to prevent instrument failure from causing spurious steam dump actuation

Answer 25

Valves close to prevent overspeeding of the turbine. LP Control Valves only throttle down on large loss of electrical load to help overspeeding of the Main Turbine. Note: during normal operation at power, HP & LP Stop Valves are normally open with LP Control Valves fully open and HP Control Valves 50% open.

Answer 26

→total of 8 speed probes (6 used, 2 installed spares) →3 probes provide input to software overspeed →3 probes provide input to hardware overspeed →each of the six speed channels (3 for hardware overspeed, 3 for the software overspeed) is automatically tested once every 24 hours when turbine >40 rpm →tests verify that speed channels trip when speed is simulated >1980 rpm

Answer 27

if bearing temp ≥245°F, turbine must be tripped immediately

Answer 28

Hardware Overspeed Sub-system utilizes a set of three dedicated speed channels, each of which provides a trip signal to the Relay Protection System. Upon receipt of trip signals from any two of these speed channels, the relay logic de-energizes all three output relays which subsequently de-energize all three Turbine Trip Block solenoid valves, causing the turbine to trip.

Answer 29

→Hardware / Software Overspeed >1980 rpm →Low lubricating oil pressure (2/3) 25 psig (2 sec time delay) →Condenser A (or B) (2/3) 21" Hg AND 900 rpm →Excessive shaft displacement (2/3 probes) > ± 39 mils →Trip Fluid Pressure <29 psig → **P-14 Hi-Hi SG Level** 84% U1, 81.5% U2 (2/3); controlling level channel not used → **P-4** → **PW Head Tank Lo Level** (2/2) <78% (if turbine >1710 rpm) → **PW Lo Flow to Stator** (2/2) <610 gpm (if turbine >1710 rpm) → **PW Lo Flow to Rotor** (2/2) <580 gpm (if turbine >1710 rpm) → **PW Low Flow to Bushings (A, B or C)** (2/3) <23.3 gpm (if turbine >1710 rpm) → **PW Hi Temp** (2/2) >140°F (if turbine >1710 rpm) → **MSR A or B Shell Level Hi-Hi** (2/3) → **Main Condenser Vacuum** <21" Hg (if turbine >900 rpm) →Generator terminal box high water level (2/3 level switches) →MSR A or B Separator Level Hi (2/3) →Generator Lockout 86-1 →Loss of Field →TG Protection →SSPS / AMSAC →Manual from MCB →Manual Local PB →SI (indirectly; not a direct trip)

Answer 30

rupture disc at 1 psig

Answer 31

The Heater Drains System functions to aid in regeneratively heating feedwater by cascading the higher energy drains through successively lower energy stages of feedwater heaters.

Answer 32

→normal - fail closed →alternate - fail open

Answer 33

→not enough stored energy →located inside main condenser, so have limited accessibility for operation/maintenance →feedwater heaters have anti-flash baffles →condensate side of feedwater heaters provided with auto isolation on Hi-Hi Level

Answer 34

Heater Drain Tank 01: →MSR Separator Drains →MSR Shell Drains →SGBD Drain →HDT-01 drains to HDT-02 Heater Drain Tank 02: →Feedwater Heaters 1, 2, & 3 →FWH 1A/B drains to FWH 2A/B →FWH 3A/B have no alternate drains (dry heater) →U2 only: FWH 3A/B have vent isolations →HDT-02 provides suction to Heater Drain Pumps

Answer 35

→Seal Water and Cold Water Injection both supplied from Condensate →Cold Water Injection provided to prevent cavitation through HDPs & TV-2598

Answer 36

→powered from uA1 and uA2 →oil coolers supplied by TPCW →minimum flow 1400 gpm →if one HDP trips, turbine will runback to <812 MWe (≈70%) at 35% per min Pumps Trip On: →Lo-Lo Level HDT-02 5%, ≤806'6" (2/2) →overcurrent, phase-to-ground →locked rotor →thermal overload (26 relay) →motor DOES NOT trip on motor overload; 74 relay is alarm only

Answer 37

→fail open AOVs →minimum HDP flow is 1400 gpm. →auto open when HDP flow <1470 gpm (both valves open on low flow from either pump) →auto close when HDP flows >1520 gpm (both valves close when both HDP flows above setpoint) →auto close 10 sec after associated pump trip

Answer 38

→close slower than check valves →protect turbine from water induction and high level Auto Close On: 1. Hi-Hi FWH Level 2. Turbine Trip Interlocked With: →associated power assisted check valve →upstream drip pot drain isolation valve →normal drain valve from its associated drains source

Answer 39

→close fast →protect turbine from overspeed due to reverse flow Auto Close On: 1. Hi-Hi FWH Level 2. Turbine Trip

Answer 40

...trip the Main Turbine.

Answer 41

Shut down immediately if: →bearing temp >200°F →lube oil temp >160°F or it doesn't build lube oil pressure

Answer 42

→Hi Level produces Control Room alarm →Hi-Hi Level FWH 1: →closes normal drains from RHDT to FWH 1 →closes Extraction Steam valve to FWH 1 →opens alternate drain valves to Main Condenser →Hi-Hi Level FWH 2: →closes normal drains from FWH 1 to FWH 2 →closes Extraction Steam valve to FWH 2 →opens alternate drain valves to Main Condenser

Answer 43

The goal is to maintain HDT-02 Level at 50%. u-LV-2592: →comes off HDP discharge header; supplies MFP suction →PI Controller, uses auctioneered high level →HDT-02 Level >50% - valve opens further →HDT-02 Level <50% - valve closes further →if level goes too low, valve could close enough that forward flow is lost u-LV-2594: →comes off HDP-02; discharges to Main Condenser Shell B →Proportional Controller; uses auctioneered low level →HDT-02 Level >65% (approx.), valve modulates open →HDT-02 Level >70% (approx.), valve fully open

Answer 44

HDP Common Discharge LV-2592 controlled by auctioneered HI signal from LT-2592A/B: →failing low has minimal impact →failing high will cause 2592 will go full open →could result in HDT level lowering to 2/2 level HDP trip (5%) HDT-02 Alt. Drain Valve LV-2594 controlled by auctioneered LOW signal from LT-2594B/C: →failing high will have minimal effect →failing low will cause 2594 to close if open Note: the Lo-Lo Level HDT-02 5% trip of the HDPs comes off of different level transmitters than the ones that control LV-2592 & 2594.

Answer 45

→AFW Auto Start, Train B →HELB, Train B (120,000 lbm/hr, 240 gpm) →valves fail closed on loss of power or air →powered from uED2-1 HELB & SGBD Isolation - "AH, PHART."

Answer 46

→Train A uED1-1 →Train B uED2-1 →fail closed on loss of power or air →failure of either train solenoid will result in closure of valves Valves Close On: →P - Phase A (train related solenoid) →H - HELB, Train A (120,000 lbm/hr, 240 gpm) →A - AFW auto start (train related solenoid) →R - Rad Hi SGBD Sample Rad Monitor (RE-4200), Train A →T - Temperature Hi >150°F downstream of SGBD HX, Train A HELB & SGBD Isolation - "AH, PHART."

Answer 47

→360 gpm per filter before resin beds →both filters normally in service

Answer 48

20 gpd primary to secondary leak with RCS activity equivalent to 1% fuel defect

Answer 49

→150 gpm →600 gpm

Answer 50

→Unit 1 - 104 gpm →Unit 2 - 35 gpm Difference is due to difference in SG material wear properties.

Answer 51

→flow after HX throttled to ~200 psig through PV-5180 →manually controlled at CB-08 →this is what starts/stops flow when aligning

Answer 52

Each line has three valves: →SGBD Isolation Valves (CIVs) u-HV-2397-2400 ("PHART" Valves) →HELB Isolation Valves u-HV-2397A-2400A ("HA" valves) →flow balancing valves HV-5175-5178

Answer 53

→not always required to be open for U1 since bottom blowdown rate is much higher →fail open AOVs →position indication from ZL lights on MCB →no auto functions

Answer 54

→SG pressure/temp rises (provides more steam to main turbine) →turbine control valves would close due to control circuit sensing that load has increased with no change in steam demand →amount of energy removed by Main Turbine remains the same; RCS temp would increase →Rx power would go down due to negative reactivity from temp increase →600 gpm flow ≈2.5% Rx power

Answer 55

→when flow is directed back to HX (to Heater Drains via HDT-01), Condensate = SGBD flow (preferred) →when flow is not directed back to HX (going to Main Condenser, CST, or Turbine Bldg Sump), Condensate = 2x SGBD flow →maintain condensate temp 35°F below Heater Drain Tank temp →prevents flashing to steam

Answer 56

→outlet temp from SGBD HX should be maintained <130°F to protect demin resin from damage

Zach Stubby's Heavy Hitters - Secondary Systems Part 2 Flashcards

(83 cards)