Turbine Flashcards
What is needed to create electric voltage?
Conductor, Magnetic Field, Relative Motion
What is the purpose of the Main Turbine?
Converts thermodynamic energy of reactor steam into mechanical energy to drive the generator
How many Turbine Bypass valves are there and what is the total steam flow (% of Total Rated) through them?
9, 33.5% total flow
What is the purpose of the Turbine Bypass Valves?
Establish flow before starting the turbine,
Steam path to condenser when turbine tripped
Reactor Cooldown.
Which Turbine Valves are throttleable? Non-throttleable?
Throttle: BPV, Control, Intercept 1, 3, &5
Non-Throttle: Stop Valves, Intermediate Stop, Intercept 2, 4, 6
#2 is throttleable for first 1” of travel
How do the Main Stop Valves logic function?
1,3, & 4 slaved to No. 2 -No 2 opens to 95% firts, then others open.
What auxiliary function does Stop Valve 1 have?
Internal bypass for chest and shell warming
What is the function of the Control vavles?
Used to regulate steam to turbine, roll and load turbine, and for overspeed regulation
How does the TB Hood Atmospheric Relief function?
Diaphram to protect hood and condenser from overpressure - knife cuts diaphram at 5psia and relief to TB atmosphere
How many Cross around Relief Valves are there and what do thye do?
Setpoint?
Failure?
7 CARs - used to protect LP piping and Moist Sep on overpressure if CIV failed closed
Setpoint at 300#
Failure:
Leakby - power drop;
Stuck Open - pressure increase in condenser section
What is the function of the Extraction Non-Return Check Valve?
Protect turbine from overspeed following Turbine Speed due to flashing in heaters - Only on B, C, & D heaters
Where do the SV/CV Above Seat drains drain to?
Main Condenser
How many BPVs are there and what is their total capacity?
9 - 33.5%
What is the interlock logic for the CIVs?
1,3,5 open first - when near ~95%, 2, 4, & 6 open
How to CIV’s function on turbine Overspeed?
1,3, 5 remain open until 105%
start to close - at 50% closed, 2, 4,& 6 start closing. ALL FULLY CLOSED AT 107%;
Evens slaved to odds
What is the purpose and speed of the turning gear?
Turns the Turb rotor at low speed (4rpm) to prevent bowing
What is initation of turning gear, and what happens?
Turbine reaches 0rpm - turning gear engages (PS 28-3)
IA needed, bearing oil header >20psig, and gen. breaker open to engage!
On auto engage - 2 bearing lift pumps trip to reduce lift and ensure engagement
What Happens to Turb Auxiliaries on a Turb Trip?
All valves except BPV close
IA shut off to Extract Non-Return Check Valves
Extract Bypass Vavles Open
A Heater Drain Bypass Opens
Where is the Turb. Thrust Bearing and what does it do?
Between A LP Turb and HP Trb - It absorbs axial rotor motion
What is the Generator affect on a turbine Trip?
Turbine Trip does not trip generator - it will reduce VARs and eventually trip on reverse power
Generator trip will trip turbine
What are the Turbine Trip signals?
Speed:
Primary Speed 110% (1980rpm) or 100% acc/dec/sec
Emergency speed - 110.3% (1985rpm) or 100%acc/dec/sec
Speed Missmatch - Senses whether turbine controllers and speed agree
Trb Shaft Distortion
Axial Thrust +/-35mils
High Vibes: - normally disabled
Overcurrent
Stator Runback failed - Stator >27935amps 2 min or >9121A 3.5min
Low Press
Bearing Header - 8psig
MSOP discharge - 105psig when RPM >1300
Mn Cndsr Low Vacuum - 20inHg
EHC - 1100psig >3sec
High Level
Moist Sep High High - 24 in for 15 sec
RPV Level High - +48in
Downstream
Generator Lockout (Main Gen 86 device)
Manual Trip - Pushbuttons on Frontstandard and MCR
What pumps are part of the Turb. Lube Oil System and their power supply?
Turning Gear Oil Pump, MCC 28-3 Bearing Lift Pumps, MCC 28-3 Motor Suction Pump, MCC 25-1 Main Shaft Oil Pump - Driven off movement of Turbine Shaft Emergency Bearing Oil Pump - BOP 250vdc
What is the Turning Gear Oil Pump purpose, setpoint and Trips?
Provides all lube oil to Bearing Oil Header when Trb not at speed;
Auto Start at 25psig - reset at 30# iol header pressure
Trip on Overload and Overcurrent
What are the bearing Lift Pumps purpose? What is their autostart and trips?
10 pumps - provides oil to bottom of journal bearign when on turning gear to reduce rotor blade chatter
Auto start A&C 5 secon after TG starts when bearing oil press >5psig
Trip on Overload, low suct press, A&C trip when TG start
What is the Motor Suction Pump? Autostarts? Trips?
Provides NPSH to MSOP when Turb <90% rated speed;
Autostart at 20psig MSOP suction Pressure
Trips on OL or overcurrent
What is the Oil driven booster pump?
Provides all lube oil in conjuction with MSOP w/out reliance on elect. power
NPSH to MSOP when >90% speed
What is the Main Shaft oil Pump? Power source?
Provides all lube oil in conjunction with booster pump without reliance on elect. power when powe >90% speed. driven by Trb shaft
What is the EBOP? Autostart? Trip?
Lube oil to trb and generator upon loss of AC power.
Auto start - MSOP discharge <140psig; TGOP <26psig
Trip: Overload or Overcurrent
What happens on a loss of lube oil at power?
Detected as MSOP malfunction
MSP auto start at 20psig MSOP suction press;
if it starts, Trb operation continues
If not, TGOP autstarts at 25psig bearing oil pressure
if starts Trb operation continues;
If no, EBOP auto starts at <140MSOP discharge & <26# TGOP Disch
If starts, Trb continues operate
If not, Turb Trips
What is the Turb Exhaust Hood Spray?
Cools the exhaust hood at low load conditins (>900rpm, less 10% load)
Auto initiaties from DEHC - Hi Temp 175F, Hi Hi Temp 225F
Sensors only on A&C hoolds - 12 nozzle - 4 on each LP Tb
What is the Gland Seal System?
Used to prevent rad levels from steam/noncondensibles to TB
How does Gland Seal function at Low Power?
Steam supply from feed valves and throttle header (4psig)
supplied until HP turbine leak by takes over at high power operation
Gland Exhauster fan provides vacuum of 10-20 inH2O to prevent steam leak to TB
Exhausted to Glad Seal Condenser, condensate to Condenser, non-condensibles go to Chminey 1.75min holdup volume
What happens with Gland Seal Feed Valve Fail closed?
Main Condenser Vacuum decreases and OG flow goes up because of inleakage from TB atmosphere
How does Gland Seal FUnction at High Power?
Steam seal feed valve closes to compensate for leakage and steam seal unloading valve opens to maintain 4# on header.
HP Turb supplies its LP Turb seal steam
Steam continues to go to Gland Seal Condenser
What does Turb Supervisory monitor for?
Mechanical stresses: Vibration and phase angle
Straightness - eccentricity
Loss of blade clearances - Rotor, shell and differential expansion
Rotor Expansion - LP Rotor
Shell Expansion (HP Rotor to Shell Differential)
Bearing Deterioration
