Steam Generators

Question 1

Purpose of the Steam Generators

Answer 1

• Transfer RCS heat to dry saturated steam
• Heatsink for RCS during normal operation and shutdown

Question 2

Describe the primary and secondary coolant flow paths through the steam generators

Answer 2

• Primary
  
  • RCP, Reactor, Pressurizer, Steam Generator, RCP
• Secondary
  
  • Condensers, hotwell, hotwell pumps, iron Filtration Units, Steam jet air ejectors, Turbine Auxilary Cooling, Condensate Booster Pumps, drain coolers, 1-4 Heaters, Main feed pump strainers, Main feed pumps, Heaters 5,6, Steam Generators, High Pressure Turbine, MSR’s, Low Pressure Turbines, Condensers

Question 3

Purpose of the Main steam system

Answer 3

• Supplies steam to
  
  • control the plant cooldown rate during blackout using TDAFP
  • Make power with the main turbine
  • Main Feed Pumps
  • Aux steam header
  • Steam dumps

Question 4

How do the Main Steam Safety valves prevent secondary overpressure

Answer 4

• Safety Valves which account for 6% reactor power each
  
  • 2 at 1065
  • 2 at 1075
  • 1 at 1085

Question 5

Describe Porv setpoint and reactor power rating

Answer 5

1 for each steam generator at 1025 pisg and good for 2.5% reactor power

Question 6

Describe steam generator stop valves including normal and emergency methods of operation

Answer 6

• Closes to prevent steam line from blowing down
  
  • this minimizes positive reactivity effects
• can be closed from dump valve actuation from the control room
• Locally can be closed by isolating the control air source to a dump valve and opening the drain valve