Degraded Power

Question 1

What are entry conditions?

Answer 1

1) Only EDG power available to 4160V buses following RX trip
2) DG becomes available during blackout

Question 2

What steps are taken if only one EDG or only AAC DG in service?

Answer 2

1) RT-21
2) B55/56 to running DG
3) Align SW (Close ACW isol, SW Xtie with opearting diesel, and associated ICW Supply)
4) Place AAC DG in service on dead bus
5) If AAC not available, select P36B and P4B to running EDG side and put ADV on hand jack if > 1040#.

Question 3

What actions are taken during blackout for EFW and SGs?

Answer 3

Actuate MSLI for both SGs and verify proper EFW actuation (RT-6).

Question 4

What actions are taken for the ADV?

Answer 4

If IA lost to ADV control valve and isolation is not energized then place ADV on handjack and control 1000 - 1040 psig

If IA lost to ADV and isolation energized, establish control using the isolation valve.

Question 5

What actions are taken for the RCP seals?

Answer 5

RCP seals bleedoff is isolated to prevent heatup (bleedoff to quench tank valves are closed and seal bleedoff normal flow path isolated using CV-1274 or individual valves).

Question 6

When is transition made to ESAS in degraded power?

Answer 6

LOSCM and RCS pressure < 150 psig

Question 7

What transition is made if RCS leak is un-isolable and RCS pressure > 150 psig?

Answer 7

Go to natural circulation cooldown

Question 8

When is rapid cooldown performed during degraded power?

Answer 8

All of the following

• LOSCM
• HPI Flow < full flow from one HPI pump
• RV head void indicated

Question 9

When is A-3/A-4 cross-tied during degraded power?

Answer 9

If A-3 de-energized and P-7A unavailable, then energize A-3 from A-4 and start P-7B (Overheating Section).

Question 10

What voltage is checked for offsite power on SU1 (Step 74)?

Answer 10

SU1 voltage greater than 22 KV

(SU1 considered degraded if voltage < 22 KV)

Question 11

What is required for SU2 to be considered available and not degraded for manual transfer of vital and non-vital buses?

Answer 11

1) SU 2 Volt regulator out of service with voltage > 162.5 KV or in service in auto with 3% reduction dsiabled and voltage > 155.4 KV.
2) Any U2 SU2 loads are vital only and < 4.4 MVA
3) One or both 161 KV lines in service

Question 12

What actions are taken if offsite power is unavailable or degraded?

Answer 12

Crosstie B-1 with B-2 supplying for A ICW pump, perform Att 1 (Deg power breaker alignment and UV relay defeat) and energize A-2 from SU1 or SU2 by removing HS from PTL.

Question 13

When is A-2 powered from A-4? What loads are desired to be restored?

Answer 13

If A-2 cannot be energized from off-site power and 2 EDGs operating properly then verify Att 1 complete and Close A-409.

Question 14

What steps are performed if only one DG is operating?

Answer 14

Go to step 108

Purge gernator, open vacuum breakers, perform cleanup items and wait for offsite power or DG to become available

Question 15

What is the max KW loading prescribed to be maintained when DG supplying A-2?

Answer 15

< 2750 KW

Question 16

What actions are performed in Att 1 (Degraded Power Breaker Alignment and UV Relay Defeat)?

Answer 16

Opening breakers on A-2, defeating A2 feeder breaker UV close permissive inerlocks and UV trips by pulling fuses, open breakers on B-4, B-2 and B-1, and opening MCC breakers on B12, 22 and 42 except for P-33A (B12)/ CRD, ICW and Cond Xfer pumps (B-22) / IA comp and Breathing Air compressor on B-42.

Question 17

What actions are taken if ESAS actuates in degraded power?

Answer 17

Perform RT-10 only