40AO-9ZZ08 Load Rejection

Question 1

For 40AO-9ZZ08 Load Rejection, what are the exit conditions for Main Turbine trip?

Answer 1

Condition 1:
- Power ≈ 20% and decided to S/D

Condition 2 & 3:

• Either decide to Restore Turbine OR maintain conditions
• Power 7-12%
• CEA’s support restore turbine OR maintaining conditions
• ZZ04 Mode 2 to Mode 1 entered

Condition 4:
- Power stabile 7-12% decide to S/D

Question 2

For 40AO-9ZZ08 Load Rejection, what are the exit conditions for Partial Load Rejection?

Answer 2

Condition 1:

• Cannot overcome Xe OR decide to reduce power
• Time limits for power reduction determined
• ZZ05 entered for power reduction

Condition 2:

• Power stabile and decide to raise power
• CEA’s > TIL
• ZZ05 entered to raise power

Condition 3:

• Power stabile and decide to maintain
• CEA’s > TIL
• ZZ05 entered

Question 3

For 40AO-9ZZ08 Load Rejection, what is Rx Trip Criteria for Turbine Trip?

Answer 3

• Power was ≥ 74% and RPCB fails auto/man
• CEA deviates from subgroup > 6.6” and any CEA reg group < TIL
• SGWL trips challenged
• RG 3 < 60” withdrawn
• Power > 12% and SBCS interlock in and can’t reset
• CPC ASI (pt 187) > ±0.45 trending 0.5
• Unit S/D desired for repairs

Question 4

For 40AO-9ZZ08 Load Rejection, what is Rx Trip Criteria for Partial Load Rejection?

Answer 4

• Generator cannot be stabilized AND RPCB not in svc (trip turbine if RPCB in svc)
• CEA deviates from subgroup > 6.6” and any reg group < TIL
• RG 3 < 60” withdrawn
• SGWL trips challenged
• CPC ASI (pt 187) > ±0.45 trending to 0.5
• < 410 MW and vacuum > 5”HgA or > 4”HgA for 1 hour

Question 5

What are the consequences of manually actuating RPCB LOFP during a LLR?

Answer 5

• SBCS receives Quick Open Block

- Rx Trips on High PZR Press

Question 6

During 40AO-9ZZ08 Load Rejection following a Turbine Trip at what power do you stabilize and why?

Answer 6

12%

• CPC use canned ASI value
• ↓Condenser erosion
• DCCV swapover
• FWCS 1E control
• LCO for Tilt and ASI not applicable <20%

Question 7

During 40AO-9ZZ08 Load Rejection following a turbine trip, is the time goal for reducing power

Answer 7

Reduce power to ≈ 12% in

90 MINUTES

Question 8

Following 40AO-9ZZ08 Load Rejection, how is CEA overlap restored?

Answer 8

If RG 3 withdrawn > 95”

• Withdraw RG 4 to RG3-95”
• 10” pulls
• Waiting 1 minute between pulls

Question 9

When down powering following RPCB Load Rejection, at what power do you stop borating?

Answer 9

• 17%

- Stabilize 10-12% via CEA/dilution