Condenser Air Removal

Question 1

Describe normal L/U for air ejectors?

Answer 1

4 primary ejectors (out of 8) taking suction on main condenser (one per quadrant ) lined up to discharge “inter condenser”, both secondary air ejectors take suction off inter condenser, disch to after condenser. After condenser -> FIT-81, RM-15/15R-> plant vent

Question 2

What is the “boot seal”? How is boot seal protected from steam? How do we ensure any small leaks in boot seal don’t make us lose vacuum?

Answer 2

The expansion joint between mn cond and main turbine The impingement shield on inside of cond There is a water seal tray that is kept full and flow that overflows tray is monitored=> indication of large leakage

Question 3

Where does air ejectors take suction from main condenser?

Answer 3

Center of tube bundle, tubes gradually get closer together, directing steam flow to pass by suction

Question 4

Functions of condenser & air removal? Safety functions?

Answer 4

• collect exhaust from LP turbine, few turbine - collect steam from stm dumps (grps 1 & 2) - condense steam for re-use in cond & fw - maintain vacuum for plant efficiency - maintain hotwell level for NPSH for cond pumps - remove non-condensible gases for vacuum & chem Means for saltwater leak detection ( protect S/G) Means for primary-> leak detection ( protect public)

Question 5

Where is steam coming from that goes to SJAE?

Answer 5

Aux steam, vital (100#)

Question 6

Describe construction of MN condenser?

Answer 6

Two separate condensers connected at hotwell and steam space. One condenser makes up South (east & west) quadrant, the other makes up North ( east & west) quadrant. Circ water flows in between north and south quadrants and flows outward. One circ water pump will supply both a north and south quadrant (east or west). All three LP turbines feed both north and south quadrants=> one CWP can supply cooling to all three LP turbines ( just no enough capacity)

Question 7

What is function of hogger?(Nash vacuum pump)

Answer 7

Remove the initial non condensible gases, good at removing non-condensibles, not drawing/maintaining vacuum=>only on line at beginning of S/u

Question 8

Purpose of N2 injection? Purpose of O2 injection?

Answer 8

Sweeps stagnant O2 to SJAE to lower [O2] Reduce FAC by maintaining proper conditions to preserve layer of magnetite(protective corrosion layer)

Question 9

How is seal maintained on vacuum breaker? What is vacuum breaker used for? (CND-506)

Answer 9

Seal water on external piping Used to allow air into condenser to break vacuum and slow the turbine down much faster than with vacuum (Do not break vacuum >200 rpm)

Question 10

What system(s) must be in service to operate SJAE or hogger?

What is minimum press in ASS for SJAE to work?

What RPM should you be below to break vacuum?

Answer 10

• GSS (seal condensors) and U-1 SCW (vacuum pump)
• > 85#
• 200 rpm