Main Steam and Turbine

Main turbine converts thermal energy into useful work

Turbine oil system provide turbine and generator lubricating needs

• High pressure fluid for valve actuation, turbine
• control and tripping

Steam sealing system prevent steam leakage from turbine case, prevent air leakage inward

HP Turbine

LP Turbine

3 - 5 PSIG reduced from main steam

> 5.5 PSIG

• Relief Valve at 25 PSIG
• Rupture Disc at 100 PSIG

• Low Vacuum
• High thrust bearing pressure
• Overspeed (1990 RPM)

• Spray at 142^oF
• Alarm at 175^oF
• Trip at 250^oF

•35 psig alarms TURB THRUST BRG WEAR annunciator window E-1/3.

•75 psig alarms TURB THRUST BRG TRIP annunciator window E-6/1.

•At 75 psig a turbine trip occur

A MCC / B MCC

• Auto starts at 14" below ground level
• Auto stops at 48" below ground level

3A MCC / 4A MCC

<32 Amps Steady

• Turbine spinning down from 600 rpm
• Starts Bearing Lift Pump
• Opens SV-3400 to supply oil to TG & zero speed indicator
• At zero speed open 20/TGE and 20/TGV to engage Turning Gear

• 11' diameter cylindrical tank with a capacity of 14,800 gallons and is common to both units. 1 Storage tank that can take oil from either units lube oil reservoir but not both at the same time.
• Lube Oil Tank should normally be empty

13,875 gallons full. Normal level is 10,000 gallons

Fire Protection. Pipe inside of a pipe to prevent leaks directly onto the turbine which would flash to fire

Shaft driven and mounted in the governor end of the turbine. Starts at ~1700 RPM

• 200 HP U3, 250 HP U4 - LC3(4)C
• Suction below the oil level to eliminate need of priming.
• Consists of 2 pumps on common shaft.
• High pressure (Low volume/capacity)
• Low pressure (High volume/capacity)
• At startup supplies suction for main oil pump and oil to the zero speed indicator.
• Auto start (Switch in Mid Position) on decreasing bearing oil pressure of »10 psig

• Vertically mounted on Turbine lube oil reservoir.
• 40 HP (Same on both units) - MCC 3A [MCC 4A]
• Pump is self priming with suction below oil level
• Discharges to:
• –Bearing oil
• –Seal oil backup
• Auto start – pump starts on low bearing pressure »9 PSIG (PS-3609) and no LOOP on “A” or “B” Bus

• Same type pump as turning gear oil pump
• Motor driven - 40 HP DC (Same on both units) 3(4)D31
• Pump is an emergency backup if AC is lost.
• AUTO - Pump starts on low bearing oil pressure of »7 PSIG (PS-3608)

• Multi-vane, positive displacement, horizontal pump
• Motor driven - 25 HP on Unit 3; 20 HP on Unit 4
• MCC 3A [MCC 4A]
• Used on turbine startup, shutdown, and TG operation.
• Supplies lift oil to all but the extreme north and south turbine bearings including the generator bearings.
• Takes suction on the bearing oil discharge header cooler outlet
• In AUTO pump starts when rotor speed decreases to 600 RPM and Bearing oil supply pressure >9 PSIG.

• Two
• Mounted inside the reservoir below the oil level.
• Uses main oil pump discharge as the motive fluid.
• Fluid pumped is the reservoir oil.
• Large flow of low pressure oil
• Zero speed indicator
• Turbine and generator bearings
• Turning gear.
• Main oil pump suction (other ejector)

TPCW

• Motor driven blower
• Removes and discharges to atmosphere, oil vapors rising from the reservoir and H2 gas.
• Provides a low pressure area for better drainage
• Normally in operation (Must be in operation when turbine is idle or <600 RPM with an oil pump in operation)
• Vacuum on the Lube Oil Reservoir should be maintained between 4 to 5 inches of water as indicated on PI-4-1559

• Removes foreign particles and water from the turbine Lube oil.
• Contains three main compartments and a pump, associated piping, valves & controls.
• Located below and to the east of the Lube Oil Reservoir.
• Variable speed positive displacement pump – from reservoir to the conditioner then back to reservoir.
• Normally in service cleaning the oil in the lube oil reservoir.
• Turbo-Toc pump has internal relief to protect from dead head conditions.
• Powered from non-vital MCC 3(4)A
• Local Start-Stop pushbutton.
• The 3 main compartments of the conditioner:
• –Pre-filter - 3 filter elements sized for 6 microns
• –Coalescer vessel - 2 compartments of coalescent filters
• –Polishing filter - 3 filter elements sized for 2.8 microns

• Regulates the speed and load of the main turbine.
• Controls amount of steam flow through turbine.
• Provides turbine protection

• Drive the turbine generator such that the generator may produce its rated megawatt output (MWR) of 774 MWe
• Turbine trip initiates a reactor and generator trip above >10% power
• Generator trip to prevent motorizing the turbine

Located between MSIVs and turbine control valves

• PI-3413 (30 PSIG @ 1800 RPM)
• Constant 15 GPM flow from main oil pump

• Controls speed when synchronizing turbine
• Controls load when on the line

• Lower
• Raise
• Auto

Controls turbine speed when speed increases to between 1850 and 1950 or acceleration is >3% / sec.

• Low bearing oil pressure
• High thrust bearing oil pressure
• Low vacuum
• Solenoid valve (20 AST) operates tripping lever
• Overspeed trip

Trip weight forced outward due to centrifugal force at 1998 RPM

Handle in TEST position blocks all trips (except 20-ASB).

• Thrust bearing located between the two LP turbines
• Shoes wear as rotor turns
• Trip shuts down turbine before turbine blades are damaged due to axial movement.

2 Stop Valves and 4 Control Valves

• Supplies steam to main turbine throttle valves
• Reheats steam to low pressure turbines
• Supplies steam to steam jet air ejector, hogging jets and water box priming jet
• Supplies steam to gland sealing steam system
• Supplies steam to auxiliary feed pump turbines
• Provides means of RCS temperature control using Steam Dumps (atmos. & condenser)
• Supplies steam to the auxiliary steam system pressure reducing station
• Supplies steam for the turbine cylinder heating system

• Extracts steam from main turbine
• Preheats feedwater in feedwater heaters
• Improves steam cycle efficiency

• Unit 3 Nitrogen Backup
• Unit 4 Air Accumulator

• RV-1400 (1405, 1410): 1085 psig
• RV-1401 (1406, 1411): 1100 psig
• RV-1402 (1407, 1412): 1115 psig
• RV-1403 (1408, 1413): 1130 psig
• T/S- Mode 3 or Above: Safeties Operable!

• Close on “Steam Line Isolation”
• Annunciator C-8/2
• Containment High (4PSIG) and High-High Pressure (20PSIG)
• High Steam Flow (40% to 114%) coincident with:
• Low Tavg (543^oF)
• or
• Low Steam Line Pressure(614 PSIG)

• One per steam line
• Air Operated Stop Check
• Header A: POV-3/4-2604
• Header B: POV-3/4-2605
• Header C: POV-3/4-2606

armed

The more the dump valves are open

• RV6264 - 288 PSIG
• RV1422 - 275 PSIG

• Condenser Waterbox Aux Priming Ejectors
• Back-up Supply to the AFW pumps
• Opposite units main steam line warm-up

3B49