Unit 2 Main Turbine Flashcards
Describe the flow paths in the
Turbine Control fluid system.
– Main EHC pumps take a suction from the EHC tank and discharge through the distribution block – In the distribution block the flow path is past the individual relief valves, then through the pump individual isolation valves and discharge check valves. Next in the block is the filter selector valve. – The fluid exits the block and passes through the discharge filters. (3 micron) ►Fluid continues past the Four Accumulators and out to the system loads – Main Feed Pumps – Main Stop Valves – Front Standard – Main Control Valves – Right Intermediate Valves – Left Intermediate Valves
Explain how the Unit 2 Main
Turbine Control system
functions to provide turbine
control and protection.
regulate steam flow to the turbines by operating the main turbine stop and control valves, and the reheat stop and intercept valves.
Explain how to operate any of the following Unit 2 Main Turbine and Control System local controls: A. Main turbine trip B. Cleanup and Cooling Filter C. Main EHC Filter
A. Push or pull the handle. B. 5 Micron Cleanup Filters Swap Cleanup/ Cooling Filters as follows: 1. Open 2-TCF-96, HPU Cleanup/Cooling Fluid Filter Equalization Valve 2.Swap Cleanup/ Cooling Filters using 2-TCF-95 Cleanup/ Cooling Filters Manual Selection Inlet Valve 3. Close 2-TCF-96, HPU Cleanup/Cooling Fluid Filter Equalization Valve C. 3 micron Full flow Discharge Filters Switching filters 1. Open control fluid filter pressure equalization valve 2. Vent the filter to be placed in service 3.Verify outlet valve for the filter being placed in service is open 4. Swap control fluid filters using 2-TCF-68, HPU Skid Filter Selection manual Inlet. 5. Close the control fluid filter pressure equalization valve.
What are the trips of the main turbine?
Manual (control room and front standard).
IOPS.
SI, Reactor trip, SG HI HI trip.
Stator water low flow/pressure trip, high temp.
Generator unit overall differential trip.
Over speed.
AMSAC.
Thrust bar ware high.
Lube oil/Control fluid pressure low.
Loss of power to both DCS power supplies.
Vacuum loss
Explain when the test solenoid manual override for the Unit 2 Main Turbine Stop and Control Valves would need to be used by an AEO.
► If after 30 seconds the valve being tested does not move the AEO
at the valve will be directed to manually override the solenoid using
ATT. 4 or 6 with 6 being the preferred.
► Verify yellow LED on the plug for the corresponding test solenoid is
LIT.
► This lets you know there is voltage to the Test solenoid.
► I/E the test circuitry is activated.
The 30 second time is to give a time
limit to begin action only. There is no
timeout circuitry so this action needs
not to be rushed in any manner.
IF testing a High Pressure Turbine Stop Valve THEN
perform the following:
► a. WHEN the ‘Continue Test’ button has been
depressed (on
the HMI ), THEN perform the following:
► 1. Verify yellow LED on the plug for the corresponding
test solenoid is NOT lit.
► 2. Push in AND turn clockwise to lock the manual
override
operated in Step 4.1.2 of this Attachment back in the
normal IN position.
IF testing an IV or RSV, THEN perform the following:
► WHEN applicable turbine valve Dump & Test Solenoids
are De-Energized (visible on the HMI), THEN
perform the following:
► 1. Verify yellow LED on the plug for the corresponding
test solenoid is NOT lit.
► 2. Push in AND turn clockwise to lock the manual
override operated in Step 4.1.2 of this Attachment back
in the normal IN position.
What position must the control valve be in to open the stop valve
Control valve has to be closed to open the stop valve
What is the function of the high pressure turbine control valves?
To regulate the amount of steam flow to the high pressure turbine.
Hydraulic open spring close.
What is the function of the main steam stop valves?
Quickly shutoff the steam flow to the high pressure turbine in emergency situations.
Hydraulic open spring close.
What is the purpose of the reheat stop valves?
Protect the turbine from over speed following a trip.
Hydraulic open spring close.
What is the function of the intercept valves?
Limit speed on a load rejection.
Normal open, throttles on startup
and load rejection.
Hydraulic open spring close.
What is the function of the hood spray system?
To cool the final stages during low power operations we have exhaust hood spray. ►2-CMO-40 Opens in Auto when – Permissive from DCS says generator load is less than 20% based on average generator amps AND – Either Steam Seal Supply Header Isolation Valve (SRV-26 or SRV-27) OPEN
What do journal bearings do?
Support the shaft and and maintain radial alignment of the shaft.
What do thrust bearings do?
Prevents axial movement of the shaft.
What will auto start an EHC pump?
When in “Auto1” a control fluid pump will
start under any of the following conditions.
► Selected control fluid header pressure is
Describe the flow path of steam
through the Main Turbine from
the Main Steam header to the
Main Condensers.
From the steam generators, Pass the PORV’s and safeties, through the main steam stop valve through the control and stop valves, to the high pressure turbine, through the cross under to the MSR, through the reheat stop and intercept valves, to the low pressure turbines and exhausted to condensers.
