E-3 Series EOP's Flashcards
What are the FOP criteria for E-3? (S/G Tube Rupture)
- SI Reinitiation: Following SI termination, if either condition occurs, then manually establish ECCS as necessary to restore conditions AND go to ECA-3.1 (SGTR w/ Loss of Rx Coolant)
- Subcooling < 40F
-OR- - PZR level cannot be maintained >16%
- Subcooling < 40F
- Secondary Integrity: If any S/G# is lowering in an uncontrolled manner OR has completely depressurized, and affected S/G was not previously isolated using E-2, then go to E-2 unless needed for cooldown.
- Cold Leg Recirc: If RWST goes < 30%, go to ES-1.3 (Transfer to Cold Leg Recirc)
- AFW Switchover: If CST level goes <15%, then switch to alternate AFW supply.
- Multiple Tube Rupture: If any intact S/G level rises uncontrollably OR has abnormal radiation, then stabilize the plant and return to E-3, step 1.
- RHR Pump Restart: If RCS# lowers uncontrollably to <300#, then manually restart RHR pumps.
- Control Room Pressurization: Maintain one and only one pressurization fan running during subsequent recovery actions.
How is the amount of leakage into a Ruptured S/G contolled?
- The ruptured S/G is isolated from the intact S/G’s. This will allow for the ruptured S/G and RCS pressures to equalize.
- The RCS is then cooled down using an intact S/G. Lowering RCS pressure < ruptured S/G will cause leakage into the RCS.
What is the Ruptured S/G PORV setpoint changed to and why?
- Adjusted to 1040#
- Still provides pressure relief during an overpressure condition, but raising to a higher setpoint than the other S/G’s will minimize the radiological release.
What is the time commitment to isolating steam flow from the Ruptured S/G?
18 minutes
If offsite power is lost AFTER resetting SI, how is EDG load overload prevented?
Manually placing the Load Con Initiation switch (101-LCTA(B) to “Load Con” for the applicable train.
How is feed flow to the ruptured S/G controlled?
- Maintain feed flow until the ruptured S/G NR level is >13% then STOP feed flow.
Can a ruptured S/G that is also faulted be fed?
- No, feeding a faulted and ruptured S/G may cause a large cooldown, increase the amount of RCS to secondary leakage, and cause the S/G to overfill.
- The exception is if the faulted and ruptured S/G is the only S/G available for cooldown.
While performing E-3 (SGTR), why is RCS pressure checked to be >450# prior to initiating a cooldown?
- If pressure is <450#, the cooldown (performed rapidly as possible) could cause a PTS to the RCS and develop an ORANGE path on Integrity.
- Operators are directed to ECA-3.1, which limits the cooldown rate to prevent PTS.
If cooling down using Natural Circulation during E-3, how could a FALSE Integrity CSFST indication occur on the ruptured loop?
- The cooldown will cause ECCS flow through the ruptured S/G RCS loop to reverse. This will cause cold leg temps to lower to the point of FR-P.1 being met.
- Disregard the ruptured S/G RCS cold leg temp until after the cooldown/depressurization and SI is terminated.
What is the minimum differential pressure between the Ruptured and Intact S/G’s before ECA-3.1 must be entered?
- 250#
- About 250# is required at no-load temperature to stop RCS to secondary leakage while maintaining subcooling.
While using the PZR PORV to lower RCS pressure during E-3 the PRT rupture disc blows, causing high radiation levels in containment. Should the operator transition to E-1? (Loss of Rx or Secondary Coolant)
- NO
- Bases recommend continuing with E-3 to stop RCS to secondary leakage until otherwise directed.
What is the difference between a S/G Tube Leak and a SGTR?
- S/G Tube Leak: Leakage is within the capability of the CVCS system (One charging pump with letdown isolated).
- SGTR: Leakage is greater than the capability of the CVCS. SI will be required to maintain RCS inventory.
What is the maximum capability of the CVCS system in terms of a S/G Tube Leak?
One charging pump with maximum flow and letdown isolated.
What are the time critical actions during E-3? (SGTR)
- Isolate AFW to ruptured S/G -> 6 min of Rx Trip
- Isolate S/G -> 18 min of Rx Trip
- Initiate cooldown -> 4 min of isolating steam flow
- Initiate depressurization -> 3 min after the end of cooldown
- Terminate SI -> 2 min after depressurization
- Max time to termination of break flow -> 51 min
What are the concerns with overfilling a S/G during E-3? (SGTR)
- Liquid entering the main steam piping may exceed design loading causing a break.
- Water hammer of the steam piping and equipment.
- Turbine blade erosion.
- S/G Safeties and PORV’s are not designed to pass water. They may stick open or break.
What are the advantages and disadvantages of ES-3.1? (Post SGTR Cooldown Using Backfill)
Advantages:
- Minimizes radiological release.
- Facilitates processing of contaminated coolant.
Disadvantages:
- Adverse S/G chemistry effects on the RCS.
- Boron dilution event.
- Much slower at cooldown and depressurization.
