40AO-9ZZ07 Loss of Condenser Vacuum

Question 1

At what condenser pressures does the D AR pump AUTO start?

Answer 1

A - ≥4.2” HgA
B - ≥4.8” HgA
C - ≥5.3” HgA

Question 2

At what condenser pressure does the SBCS Cond Interlock come in?

Answer 2

• ≥5.5” HgA

- 2/3 shell logic

Question 3

How is the SBCS condenser interlock reset?

Answer 3

• Condenser press <5” HgA

- Taking Emergency-Off-Reset to reset

Question 4

What condenser pressure causes a Turbine Trip?

Answer 4

• ≥7.5” HgA

- 2/3 logic

Question 5

What condenser pressure causes a MFP trip?

Answer 5

• ≥13.5” HgA

- 2/2 logic (turbine exhaust)

Question 6

During 40AO-9ZZ07 Loss of Condenser Vacuum, what is Rx Trip Criteria?

Answer 6

Generator Online

• > 7” HgA and ↑
• <410 MW and >5” HgA
• <410 MW and >4” HgA for >1 hr
• < 70 MW and load reduction needed

Generator Offline

• Prx >12% and SBCS interlock come in
• Prx 3-12% and >7” HgA ↑ AND, MFP tripped

Question 7

What is the control power for Cooling Tower Fans?

Answer 7

NKN-D19

Question 8

What is the required power reduction if BOTH CW pumps in a loop are lost?

Answer 8

Reduce power to ≤ 40%

Question 9

During 40AO-9ZZ07 Loss of Condenser Vacuum, does the D AR pump need to be running to open shell suctions?

Answer 9

• NO

- Opening all D Suctions x-ties suctions to allow other AR pumps to assist 1 shell

Question 10

What Hotwell Level do we maintain and why?

Answer 10

• ≥ 41”

- HDP trip lowers level ≈ 10”

Question 11

What is the concern with hotwell m/u during 40AO-9ZZ07 Loss of Condenser Vacuum

Answer 11

• M/U uses vacuum drag, as vacuum ↓ M/U is affected

Question 12

During 40AO-9ZZ07 Loss of Condenser Vacuum, what is the minimum power reduction?
How is it performed?

Answer 12

• 5% (Mentor Guidance 10% over 10 minutes)
• Allow CEA insert automatically
• Tavg/ref target +3-3.5°F
• Boration allowed if CEA’s in manual
• Do NOT exceed Lpzr 56%
• Maintain Tavg/ref ±5°F, CEDMCS out of Auto and use 1007/8 if cant maintain
• Tc ±3°F of program band