Mositure Separator Reheater(MSR)

Question 1

What is the purpose of the Moisture Separator Reheaters?

Answer 1

The purpose of the Moisture Separator Reheaters is to remove moisture and increase the heat energy of the steam leaving the High Pressure Turbine to:

1. Reduce LP Turbine blade erosion
2. Increase turbine/cycle efficiency

Question 2

What is the change in pressure and temperature of the steam as it exits the Moisture Separator Reheaters?

Answer 2

The MSRs increase the pressure of the steam by approximately 150psig and the temperature by approximately 150F

Question 3

What is the flow path through the Moisture Separator section of the MSR?

Answer 3

1. Steam from the High Pressure Turbine flows up through the bottom of the shell into the chevron separators where entrained moisture is removed
2. The moisture is collected and sent to the Moisture Separator Drain Tank
3. Plates and baffles are used to ensure the steam does not bypass the separator section

Question 4

What is the design/purpose of the MSR’s First Stage Reheater?

Answer 4

1. Four pass design(tube side) using ‘A’ Bleed Steam
2. The wet vapor of the HP Turbine exhaust is superheated as it travels through the stage
3. The first stage inlet isolation valves are operated from the control room, and are opened prior to rolling the turbine with main steam

Question 5

What is the design/purpose of the MSR’s Second Stage Reheater?

Answer 5

1. Main steam travels through the tubes and further superheats the steam
2. Main steam flow is controlled from a local panel

Question 6

How is steam flow controlled using the Low Load Valves to the Second Stage Reheater of the MSR?

Answer 6

1. If left in automatic the Low Load Valves would throttle open from 15%-65% load
2. We throttle the Low Load Valves open manually from 20%-65%
   * We throttle the steam to the 2nd Stage Reheater to prevent sending steam that is too hot to the LP Turbine during low load conditions*

Question 7

How is steam flow controlled using the High Load Valves to the Second Stage Reheater of the MSR?

Answer 7

1. High Load valves will automatically open 65% load and are not used for throttling
2. We open the High Load Valves manually at 65% load

Question 8

Where do the drains from the Moisture Separator Reheater go?

Answer 8

1. Moisture Separator Section - Moisture Separator Drain Tank
2. First Stage Reheater - First Stage Reheater Drain Tank
3. Second Stage Reheater - Second Stage Reheater Drain Tank

Question 9

Where do the Moisture Separator Reheater Shell Drains go?

Answer 9

1. There are two drain lines equipped with an orifice that route drains constantly to the Main Condesner
2. Each drain line has an motor operated bypass valve aid in turbine warming

Question 10

When does the Motor Operated Bypass Valve around the orifice in the MSR shell drains operate automatically and when do we operate them manually?

Answer 10

1. The bypass valves are opened when load is less than 15%
2. The bypass valves are throttled during turbine warming to maintain 60-100psig pressure
3. The bypass valves will automatically close when at 15% load

Question 11

Where do the MSR Moisture Separator Drain Tank normal and alternate drains go?

Answer 11

1. Normal - ‘C’ Heater Drain Tank

2. Emergency - Condenser

Question 12

What will cause the MSR Moisture Separator Drain Tank Normal Drain Valve to open and close?

Answer 12

1. Open - Greater than 10% load to control level
2. Closed:
   A. When load is less than 10%
   OR
   B. Emergency high level in the ‘C’ Heater Drain Tank

Question 13

What will cause the MSR Moisture Separator Drain Tank Alternate Drain Valve to open and close?

Answer 13

1. Open:
  A. Less than 10% load
OR
  B. Moisture Separator Drain Tank high level
2. Normally closed

Question 14

What will cause the check valve in the MSR Moisture Separator Drain Tank Normal Drain Valve line to close?

Answer 14

1. Less than 10% load
   OR
2. ‘C’ Heater Drain Tank high level

Question 15

Where do the MSR First Stage Reheater Drain Tank normal and alternate drains go?

Answer 15

1. Normal - ‘B’ Heater

2. Alternate - Condenser

Question 16

Where do the MSR First Stage Reheater Drain Tank normal and alternate vents go?

Answer 16

1. Normal - ‘B’ Heater

2. Alternate - Condenser

Question 17

When is the normal vent from the MSR First Stage Drain Tank Open?

Answer 17

1. Greater than 10% Turbine load
   AND
2. ‘B’ Heater level is less than emergency high level
   AND
3. The extraction steam line to the ‘B’ Heater is open

Question 18

When is the alternate vent from the MSR First Stage Drain Tank Open?

Answer 18

The alternate vent will be open to the condenser when:
1. First Stage Reheater steam isolation is open
AND
2. The vent to the ‘B’ Heater is closed

Question 19

What will cause the MSR First Stage Reheater Drain Tank Normal Drain Valve to open and close?

Answer 19

1. Open - Greater than 10% load to control level
2. Closed:
   A. When load is less than 10%
   OR
   B. Emergency high level in the ‘B’ Heater

Question 20

What will cause the MSR First Stage Reheater Drain Tank Alternate Drain Valve to open and close?

Answer 20

1. Open:
   A. Less than 10% load
   OR
   B. MSR First Stage Drain Tank high level
   OR
   C. Emergency high level in the ‘B’ Heater
2. Normally closed

Question 21

What will cause the check valve in the MSR First Stage Reheater Drain Tank Normal Drain Valve line to close?

Answer 21

1. Less than 10% load
   OR
2. ‘B’ Heater emergency high level

Question 22

Where do the MSR Second Stage Reheater Drain Tank normal and alternate drains go?

Answer 22

1. Normal - ‘A’ Heater

2. Alternate - Condenser

Question 23

Where do the MSR Second Stage Reheater Drain Tank normal and alternate vents go?

Answer 23

1. Normal - ‘A’ Heater

2. Alternate - Condenser

Question 24

When is the normal vent from the MSR Second Stage Drain Tank Open?

Answer 24

1. Greater than 20% Turbine load
   AND
2. ‘A’ Heater level is less than emergency high level
   AND
3. The extraction steam line to the ‘A’ Heater is open

Question 25

When is the alternate vent from the MSR Second Stage Drain Tank Open?

Answer 25

1. The extraction steam isolation valve is open
   AND
2. The vent to the ‘A’ Heater is closed

Question 26

What will cause the MSR Second Stage Reheater Drain Tank Normal Drain Valve to open and close?

Answer 26

1. Open - Greater than 20% load to control level
2. Closed:
   A. When load is less than 20%
   OR
   B. Emergency high level in the ‘A’ Heater

Question 27

What will cause the MSR Second Stage Reheater Drain Tank Alternate Drain Valve to open and close?

Answer 27

1. Open:
   A. Less than 20% load
   OR
   B. MSR First Stage Drain Tank high level
   OR
   C. Emergency high level in the ‘A’ Heater
2. Normally closed

Question 28

What is Scavenging Steam, and how does it help efficiency?

Answer 28

Scavenging Steam is the excess steam in the First and Second Stage Reheater tubes that is removed so that it doesn’t sit in the tubes and condense as heat is given up to the HP Turbine exhaust. If allowed to condense the efficiency of the MSR would be reduced.

Question 29

Where is First Stage Reheater Scavenging Steam aligned and when?

Answer 29

1. First stage is aligned to the ‘B’ bleed at greater than 10% load
2. First stage is aligned to the Condenser at less than 10% load

Question 30

Where is Second Stage Reheater Scavenging Steam aligned and when?

Answer 30

1. Second stage is aligned to ‘A’ Bleed at greater than 20% load
2. Second stage is aligned to the condenser at less than 20% load

Question 31

What parameter associated with the Moisture Separator Reheaters will cause a Main Turbine trip?

Answer 31

If the level in the MSR Drain line, on 2/3 channels, reaches 2.5 inches below the vessel bottom a turbine trip will be generated

Question 32

What parameters can be changed when Second Stage Reheater Low Load Valve Controller is in AUTO?

Answer 32

In AUTO the setpoint ‘S’ is changed by using the knob on the controller.

Question 33

What parameters can be changed when Second Stage Reheater Low Load Valve Controller is in MANUAL?

Answer 33

With the controller in MANUAL:

1. Valve position can be adjusted(V)
2. Process flow can be adjusted(P)