Moisture Separators Reheaters (MT) Flashcards
What is the purpose of the MSRs ?
-Used to improve quality of HP turbine exhaust before going into LP Turbine
-Improves plant efficiency & longer LP turbine life
How do the MSRs work ?
-Mechanically remove moisture & reheats dry steam passing across 1st & 2nd stage reheater tubes
-This minimizes erosion in LP turbine bucket & momentum losses
What steam is used for the MSR 2nd stage reheating ?
Main steam provides heating for second stage
What is aux steam used for on the MSRs ?
It’s used for steam blanketing of the MSRs
How does the Moisture Separator Section work of the MSR ?
Goes through chevron canes that puts wet steam through changes in direction, which causes heavy droplets from steam flow
What happens once dry steam flow exits moisture separator panels ?
Steam flow is reheated by tube bucndle s
Where does MSR Drain Tank drain to ?
Has level controller that directs tank discharge to either HTR Drain Tank or to Main Condenser on HI-HI Level
What happens if MSR vessel water backs up to within 3 inches ?
-Turbine trip initiates to prevent water induction in the turbine
-3level switches for 2/3logic
What does the Reheater Section do inside the MSR ?
-Supplied with heating steam that heats dried steam to superheater conditions
-Superheater steam is then directed to LP Turbine
Where is the 1st stage reheater receive its steam from ?
Receives steam from 3rd stage extraction line
What does the 2nd stage reheat require ?
Requires control system because it taps off upstream of turbine throttle valve & is therefore at main steam temp & pressure
Where does the 1st stage heater condensate drain to ?
Drains to 1st stage drain tank that drains to:
- #6 HPFWH
-Main Condenser on HI-HI lvl in tank
Where does the 2nd stage heater condensate drain to ?
It drains to the 2nd Stage Drain Tank which then drains to:
-#7HPFWH
-Main Condenser on HI-HI lvl in tank
What is the purpose for the MSR Drain Tank ?
-Collection point for moisture that was removed from HP Turbine exhaust
-Each MSR has one MSR Drain Tank
Where do the two MSR Drain Tank level control valves drain to ?
-Normal level control valve drains to to HTR Drain Tank
-High level control valve drains to Main condenser
What is the position of the MSR Drain Tank level control valves during start up ?
Startup will have Normal level control valve closed, & High level control valve will be opened
When less than 10% power what is the status of the MSR Drain Tank level control valves ? What happens when turbine power is greater than 10%?
-High level dump valve is failed open
-High level dump valve will go close & Normal level control valve will maintain level
What happens if MSR Drain Tank level has a continuous rise in level ?
-High level dump valve will modulate open to condenser
-If level continues to rise to MSR 3in setpoint, a main turbine trip initiates
What happens to the MSR Drain Tank level control valves on loss of instrument air ?
-Normal level control valve will fail closed
-High level dump valve will open
What happens to the MSR Drain Tank level control valves on a HI-HI lvl?
Normal level control valve will fail closed
Why does 3rd stage extraction used for 1st stage steam supply have acceptable rates of temperate changes ?
3rd stage extraction, temperature, and pressure of steam supplied 1st stage reheaters varies in turbine load
How is the steam supply to 1st stage bundle of the MSR isolated ?
Isolated by Motor Operated Reheat Stop Check Valve, operated from Control Room
What is the difference between the 1st & 2nd stage reheat steam supplied ?
-HP 3rd stage extraction is self regulating for the 1st stage reheat
-Main Steam needs a regulation when being supplied to 2nd stage of MSR
How is the steam supply to the 2nd stage bundle isolated ?
Isolated by Reheating Steam Source Valves(RSSV)
