AB-CN-0001          Main Feedwater / Condensate System Abnormality

Entry Conditions:

Trip or abnormality of a SGFP, condensate or heater drain pump

Associated OHAs in alarm

Associated control console system parameters in alarm

Routine plant monitoring of system parameters indicate a transient in progress

Immediate Actions:

If >P-10 and a loss of both SGFPs occurs, Trip | Confirm | EOP-TRIP-1 (no heat sink is available and manual trip preserves inventory until AF is initiated)

Verify automatic runback to 60% (reduces steam flow to within the capacity of a single SGFP)  occurs or initiate runback to ≤ 66% at ≤ 15%/minute or suction pressure >320 psig is achieved.

Control T_AVG with Rods in AUTO, or manually insert to maintain T_AVG at T_REF.

Continuous Action Summary:

If >P-10 and a loss of both SGFPs occurs, Trip | Confirm | EOP-TRIP-1

If parameters indicate system degradation and cause is not apparent, then trip and go to EOP-TRIP-1

If RCS temperature is ≤543°F, initiate Attachment 3 (must verify temperature once every 30 minutes when T_AVE <551°F with T_AVE /T_REF Dev Alarm not reset.)

l  STOP boration

l  CLOSE malfunctioning Atmospheric Relief Valve(s)

l  CLOSE malfunctioning Steam Dump Valve(s)

l  REDUCE Turbine load as required

If SG levels are not controlling in auto, then place the affected controllers in manual and stabilize level

CN47 opens or heater strings trip - isolate blowdown (except SS94s)

If a Digital Feedwater System or valve malfunction is detected AND Reactor Power is ≤10% RTP THEN REDUCE Reactor Power to ≤4% and TRANSFER to the Auxiliary Feedwater System

Subsequent Actions:

SGFP Trip:

If ≤P-10 reduce power to ≤4% and initiate auxiliary feedwater, maintain levels ±5% of program

If >P-10:

Initiate boration as necessary to maintain control rods > RIL and AFD within target

Ensure remaining SGFP is adequate for plant conditions

Ensure open CN108s and CN47 (increase available pump suction pressure)

Depress turbine trip bezel PB for tripped pump (closes latching relays needed for AF auto start on a loss of the second SGFP)

Maintain SG levels and T_AVG on program

Energize Pressurizer heaters (equalize boron concentration)

Monitor and maintain AFD and RIL within limits

Contact Chemistry for RCS samples if power reduction exceeds 15% in any hour (RCS 2-6 hrs, plant vent within 48 hrs)

Condensate or Heater Drain Pump Trip:

If SGFP suction pressure is <320 psig then open the CN108s and CN47 (increase available pump suction pressure)

Evaluate plant conditions and reduce power at ≤5%/minute to required power level

Start Heater Drain Pumps and Condensate Pumps as needed

OHA G-7, ADFCS SWITCH TO MANUAL (Two failures equired to trip to manual)

Establish manual control of any controller that has transferred and stabilize affected SG level

Load Reduction Requirements

SGFP Trip - ≤15% per minute

Heater Drain or Condensate Pump Loss - ≤5% per minute 

Notes:

25 gallons Boron 1% power reduction, no rods / no Xenon

To raise power after runback, DEHC must be reset or it will run back to 60% again.