Section 3.7.5 Auxiliary Feedwater (AFW) System

Question 1

What is 3.7.5 Auxiliary Feedwater (AFW) System?

Answer 1

3.7.5 Auxiliary Feedwater (AFW) System

Two AFW trains shall be OPERABLE

MODES 1, 2, 3 AND
MODE 4 when steam generator is relied upon for heat removal.

Question 2

How many operable AFW trains are required in Mode 4?

Answer 2

Only one AFW train, which includes a motor driven pump, is required to be OPERABLE in MODE 4.

No/little steam for turbine driving pump.

Question 3

Note 2 requires the Steam Driven Auxiliary Feed Pump to be operable prior to making the reactor critical. What does this mean?

Answer 3

This allowance is needed to provide sufficient steam pressure to perform turbine and pump testing.

It is required to be OPERABLE during subsequent MODE 1, 2, and 3 operation.

When steam generator pressure is reduced, it is not required to have design inlet pressure available to the turbine driver in order to declare the turbine driven AFW pump OPERABLE.

Question 4

Note 3 states, two AFW pumps may be placed in manual for testing, for a period
of up to 4 hours. What does this mean?

Answer 4

In this situation, the third AFW pump would still be available in the event of a plant
transient. The two pumps that are in manual could be used at the discretion of the operator.

Question 5

A note says LCO 3.0.4.b is not applicable. What does this mean?

Answer 5

• There is an increased risk associated with entering a MODE or other specified condition in the Applicability with an AFW train inoperable.
• The provisions of LCO 3.0.4.b allow entry into a MODE or other specified condition in the Applicability with the LCO not met after performance of a risk assessment addressing inoperable systems and components.
• This is not be applied in this circumstance.

Question 6

What are the actions associated with T.S. 3.7.5

Answer 6

Alpha Actions

• One or more AFW trains inoperable in MODE 1, 2, or 3. Restore train(s) to OPERABLE status. In 72 Hours

Bravo Actions

• Required Action and associated Completion Time of Condition A not met.

OR

• Less than 100% of the required AFW flow available to either steam generator.

OR

• Less than two AFW pumps OPERABLE in MODE 1, 2, OR 3.
• Mode 3 in 6 and Mode 4 in 30

Question 7

How are Mode changes or 3.0.3 entry requirements handles within the T.S.

Answer 7

Modifying Note

MODE changes or power reductions are suspended until at least 100% of the required AFW flow is available.

Initiate action to restore one AFW train to OPERABLE status. IMMEDIATELY.

Then enter MODE change.

Question 8

What makes an AFW train operable?

Answer 8

• The components and flow paths required to provide AFW flow to the steam
  generators are OPERABLE
• This requires that the two motor driven AFW pumps be OPERABLE in two diverse paths, each supplying AFW to both steam generators.
• The piping, valves, instrumentation, and controls in the required flow paths shall also be OPERABLE.

Question 9

What is the A/B AFW train?

Answer 9

Train (A/B)

• Motor driven pump (P-8A) and turbine driven pump (P-8B) in parallel
• The discharges join together to form a common discharge.
• The A/B train common discharge separates to form two flow paths, which feed each steam generator via each steam generator’s AFW penetration.

Question 10

What is the ‘C’ trian of Auxiliary Feed Water?

Answer 10

Motor driven pump (P-8C) feeds both steam generators through separate flow paths via each steam generator AFW penetration.

Question 11

What is the design basis of the Auxiliary Feed Water System?

Answer 11

To supply water to the steam generator to remove decay heat and other residual heat, by delivering at least the minimum required flow rate to the steam generators at pressures corresponding to the lowest MSSV set pressure plus 3% with the exception of AFW pump P-8C.

Question 12

What actions may be needed with P-8C operations?

Answer 12

Operator action may be required to either trip the four PCPs, start an additional
AFW pump or reduce steam generator pressure. This will allow the required flowrate to the steam generators that are assumed in the safety analyses.

Question 13

What is the completion time of 72 hours for one inoperable AFW train based upon?

Answer 13

• It is based on the assumption that at least 100% of the required AFW flow is available to each steam generator.
• If available flow to either steam generator is less than 100% of the required AFW flow, or if less than two AFW pumps are OPERABLE,
  
  • Condition B must also be entered. In addition,
• If the combined flow available to both steam generators is less than 100% of the required AFW flow, Condition C must be entered as well.

Question 14

When is Conditon B Applicable?

Answer 14

Be in Mode 3 in 6 hours and Mode 4 in 30 hours.

Condition B is applicable:

1. when the Required Actions of Condition A cannot be completed within the required Completion Time,
2. when the flow available to either steam generator is less than 100% of the required AFW flow, or
3. when less than two AFW pumps are OPERABLE.

Condition A is applicable whenever one or more trains is inoperable.
Therefore, when Condition B is applicable, Condition A is also applicable.

Question 15

When is Condition C applicable?

Answer 15

Initiate action to restore one AFW train to OPERABLE status. Immediatley.

No Mode Change or LCO 3.0.3

If the combined flow available to both steam generators is less than
100% of the required AFW flow, Condition C must be entered. Condition A & B are applicable as well.

Question 16

What is 100% flow and its implications?

Answer 16

One hundred percent AFW flow (that assumed in the safety analyses) can be provided by any one OPERABLE AFW pump and an OPERABLE flow path to each steam generator.

With less than 100% of the required AFW flow available (ie. less than the
AFW flow assumed in the safety analyses, while in MODES 1, 2, and 3,
or less than the required AFW train OPERABLE while in MODE 4 with a
steam generator relied upon for heat removal), the plant is in a seriously
degraded Condition with no safety related means for conducting a
cooldown, and only limited means for conducting a cooldown with
nonsafety grade equipment.