Main steam

Question 1

System purpose?

Answer 1

• Contains and transports dry, saturated steam from the S/Gs to the main turbine.
• Heat removal from core.

Question 2

Flow path from S/Gs to 72inch header

Answer 2

• S/Gs
• Containment wall
• R-19
• PORV (1035psig)
• Safety/Relief valves (1085,1110,1125,1140psig)
• Line to SDAFW
• MSIV
• Check valve
• 72 header

Question 3

Flow path from 72” header to condenser

Answer 3

• Exits to N and S header
• Stop Valves
• Governor valves
• HP Turbine
• MSR
• Reheat Valves
• Intercept Valves
• LP turbine
• Condenser

Question 4

Steam Flow Limiting Device

location and purpose

Answer 4

• Exit of S/G
• 7 Venturis
• prevents a rapid steam depressurization and loss of heat sink by “choking” the steam flow with a steam line break.

Question 5

Steam Flow Venturi

puprose

Answer 5

• Downstream of S/G inside containment.
• Provides signals to the Steam Generator Water Level Control system
• ALSO RESTRICTS THE STEAM FLOW IN THE EVENT OF A STEAM LINE BREAK DOWNSTREAM OF THEM

Question 6

Steam line pressure

Answer 6

• 3 Pressure transmitters on each line which are compared to the 72” header pressure transmitters.
• Used for safeguards signals

Question 7

MSIV must close in?

How? must have what to open?

Answer 7

• Within 5 seconds
• Accumulators ensure this
• <50psig to open on each side of valve

Question 8

PORV lift setpoint?

Other relief set points?

Answer 8

• 1035psig

- 1085, 1110, 1125, 1140psig