E-2 Series EOP's

Question 1

What is a Small Secondary Break?

Answer 1

• Normal plant control systems are capable of maintaining S/G levels at or near normal operating values.
• No Rx Trip occurs

Question 2

What is a Intermediate Secondary Break?

Answer 2

• Break size is beyond the capability of the MFW system and a Rx Trip occurs.
• Trip occurs some time >5 minutes after event initiates.

Question 3

What is a Large Secondary Break?

Answer 3

Causes an immediate lowering in steamline pressure to the low steamline pressure setpoint (0.5-10 seconds)

Question 4

How can a Secondary Break large enough to cause a Rx Trip NOT result in an SI?

Answer 4

• The break is downstream of the MSIV’s OR upstream of the feedwater check valves.
• Essentially the break causes the trip, but is isolated when MSIV’s or FWIV’s are closed.

Question 5

What are the Rx Protection signals generated by a Steam Line Break that would cause a Trip?

Answer 5

• Low PZR pressure (2/4 detectors <1950#)
• OPΔT
• Any signal that causes an SI.

Question 6

What are the SSPS signals generated by a Steam Line Break that would cause an SI?

Answer 6

• Low PZR pressure (2/3 detectors <1775#)
• Low S/G# (2 S/G’s <500#)
• Steamline ΔP (2/3 # detectors one one S/G >100# lower than two other S/G’s)
• Lower Containment Pressure High (2/3 detectors >1#)

Question 7

What is the time requirement for isolating AFW to a faulted S/G?

Answer 7

≤ 30 minutes

Question 8

List the Major Action Categories for E-2.

Answer 8

• Check Main Steamline Isolation
• Check for at least one non-faulted S/G
• Identify and isolate faulted S/G
• Check for SGTR

Question 9

What are the 4 reasons for controlling AFW flow during ECA-2.1 (Uncontrolled Depressurization of All S/G’s)?

Answer 9

• Minimize any additional cooldown resulting from the addition of feedwater.
• Prevent S/G dryout by maintaining minimum feed flow to the S/G’s.
• Minimize the water inventory in the S/G’s that eventually is the source of additional steam flow to containment or the environment.
• Once S/G# and flow rate lower and RCS hot leg temp rises, controlling feed flow will allow the operator to establish conditions for SI termination which in turn will minimize thermal stresses.

Question 10

What is the minimum AFW flow to S/G’s when all of them are faulted? (ECA-2.1 Uncontrolled Depressurization of All S/G’s)

Answer 10

• 25,000 pph to EACH S/G with NR level <13%.
• Prevents S/G(s) from drying out then being re-wetted. This would cause large thermal shocks.

Question 11

What is the importance of controlling RCS heatup following completion of S/G blowdown?

Answer 11

The heatup is controlled/minimized to aid in preventing PZR overfill while terminating SI.

Question 12

Failure to isolate a faulted S/G challenges what CSF’s?

Answer 12

• Integrity
• Subcriticality
• Containment

Question 13

What are the Major Actions for E-2? (Faulted S/G Isolation)

Answer 13

• Check MS isolation
• Check for at least one NON-faulted S/G
• Identify and isolate faulted S/G(s)
• Check for SGTR

Question 14

What are the Major Actions for ECA-2.1? (Uncontrolled Depressurization of All S/G’s)

Answer 14

• Reestablish any secondary pressure boundary
• Control feed flow
• Terminate SI flow
• Cool down and place RHR in service
• Cool down to cold shutdown conditions (MODE 5)

Question 15

What are the time critical actions for E-2?

Answer 15

• AFW isolated to the faulted S/G ≤30 minutes AND prior to exiting E-2.
• Faulted S/G is isolated prior to exiting E-2.
• MSIV’s are closed prior to all S/G#’s decreasing below 500# and < 5min have elapsed since a valid Steam Line Isolation signal is received.

Question 16

What are the time critical actions for ECA-2.1?

Answer 16

Control AFW flowrate to no less than 25k pph for EACH S/G in order to minimize RCS cooldown rate before the INTEGRITY CSF becomes ORANGE.

Question 17

What is the procedure flowpath for a steam break downstream of the MSIV’s? (Isolable)

Answer 17

• E-0 (Rx Trip or SI) then transition to ES-0.1 (Rx Trip Response) if SI did not occur.
• If SI did occur, continue with E-0 until kickout for ES-1.1 (SI Termination)

Question 18

What is the procedure flowpath for a steam break upstream of the MSIV’s? (Unisolable)

Answer 18

• E-0 (Rx Trip or SI) then transition to E-2 (Faulted S/G Isolation)
• From E-2 to E-1 (Loss of Reactor or Secondary Coolant) if SI termination criteria not met OR ES-1.1 (SI Termination) if criteria IS met.

Question 19

What are the FOP criteria for E-2? (Faulted S/G Isolation)

Answer 19

Trick question! There are none.

Question 20

What are the FOP criteria for ECA-2.1? (Uncontrolled Depressurization of All S/G’s)

Answer 20

• SI Reinitiation Criteria: Manually initiate ECCS flow if Subcooling < 40F OR PZR level cannot be maintained.
• E-2 Transition: Go to E-2 if any S/G pressure rises at any time except while performing SI termination in step 13-20.
• E-3 Transition: Manually initiate ECCS flow as necessary AND go to E-3 if any S/G level rises in an uncontrolled manner OR any S/G radiation monitor is abnormal.
• Cold Leg Recirc: Go to ES-1.3 if RWST level is < 30%
• AFW Switchover: Switch water supply if CST level < 15%
• RHR pump restart: Restart RHR pumps if RCS pressure lowers uncontrollably to < 300#.

Question 21

Can a faulted S/G be used for cooldown?

Answer 21

Any faulted S/G should remain isolated during subsequent recovery actions UNLESS needed for RCS cooldown to prevent reinitiation of the event.

Question 22

What conditions would require transition to ECA-2.1 (Uncontrolled Depressurization of All S/G’s) from E-2?

Answer 22

All S/G pressures lowering in an uncontrolled manner.

Question 23

While performing ECA-2.1, when are the accumulators isolated?

Answer 23

• Two RCS Hot Legs < 422.8F
• This is the lowest RCS Hot Leg Temp that ensures RCS # > Accumulator #