40AO-9ZZ06 Loss of IA

Question 1

What is the entry criteria for Loss of IA

Answer 1

• No IA compressors running
• All IA compressors with lowering/no pressure
• “IA Header Press Lo Press” alarm (95psig)
• “IA system trouble” alarm (filter dp, dryer trouble, compressor trouble)
• “IA N2 backup vlv Open” alarm (85psig)
• Loss of IA press in 1 or more headers

Question 2

During a loss of IA what is Rx trip criteria

Answer 2

• Unstable plant conditions (CRS says so)
• Unable to restore IA to CNTMT
• RCP B/O is being directed to RDT
• Prior to isolating air to CNTMT or Aux Bldg

Question 3

During a loss of IA:
What pressure will affect plant power production stability?
What pressure is the most unstable

Answer 3

• 70 psig

- 40 psig (CVCS, spray, RDT affected)

Question 4

On a loss of IA what action do you take if LD, Seal B/O, or SGBD isolation vlv fails closed

Answer 4

• Take HS to close

- Prevent uncontrolled operation when IA restored

Question 5

What is the Power supply to IAU-UV-2

Answer 5

PKA

Question 6

How is the RDT affected by a loss of IA

Answer 6

• Seal B/O directed to RDT

- RDT CANNOT be pumped

Question 7

During a Loss of IA when would you run air dryers in parallel

Answer 7

• Large DP between air receiver and downstream of dryer
• 1 dryer in svc and stby is available
• IA press is 80psig or greater

Question 8

When does N2 backup automatically align to IA hdr?

When does it reclose?

Answer 8

• 85 psig

- 105 psig

Question 9

What is the concern if N2 is supplying the IA header?

What actions are required

Answer 9

• O2 deficient atmosphere in Aux Bldg below 100’

- Start at least 1 FBEV AFU aligned to Aux Bldg

Question 10

During a loss of IA when would you isolate IA to fuel pool gates

Answer 10

• 28 psig or lower, Isolate IA

Question 11

During a loss of IA at what pressure do CD pump mini-flow vlv fail and to what position?

Answer 11

• 80psig

- Fail OPEN

Question 12

During a loss of IA at what pressure do HD pump disch vlv fail and to what position

Answer 12

• 80 psig

- Fails CLOSED

Question 13

During a loss of IA at what pressure do HDT High lvl dump fail and to what position

Answer 13

• 80 psig

- Fail OPEN

Question 14

During a loss of IA at what pressure does SBCV’s fail and to what position

Answer 14

• 80 psig

- Fails CLOSED

Question 15

During a loss of IA at what pressure do MFP mini-flows fail and to what position?

Answer 15

• 75-65 psig

- Fail OPEN

Question 16

During a loss of IA at what pressure do ECCV’s, MISV’s, and Economizer Iso. vlvs fail and to what position?

Answer 16

• 50-60psig

- Fail AS-IS

Question 17

What are the 2 methods for restoring IA to CNTMT during a loss of IA?
What method is preferred?
why?

Answer 17

• Align N2 to CNTMT IA hdr, & cross tie SVC air to CNTMT IA hdr
• Cross tie SVC to IA
• Does NOT required T-mod or CNTMT entry

Question 18

When aligning N2 to the CNTMT IA hdr what precaution must be taken and why

Answer 18

• Isolate N2 to RDT

- Prevents over pressurization of RDT when raising N2 pressure