SLC - 1.0

Question 1

What indications can an operator use to verify SLC system operation?

Answer 1

1. Start PBs backlit red
2. Squib Valve continuity extinguished and annunciator alarms
3. SLC pump discharge pressure slightly > Reactor pressure
4. SLC tank level decreasing
5. APRM level decreasing
6. Ensure RWCU isolation
7. CS Line Break Alarm

Question 2

What is the purpose of SLC?

Answer 2

To S/D the Rx from highest power without CRDs.

Question 3

List the power supplies for the SLC pumps.

Answer 3

A - 10B212
B - 10B222

Question 4

SQUIB Valve power supply.

Answer 4

SQUIB valves are powered from the motor buckets.

Question 5

What is T/S requirement for SLC pump flow rate?

Answer 5

41.2 GPM per pump.

Question 6

When do the pumps trip?

Answer 6

They trip when both level transmitters sense 325 gal remaining in the tank. (Bypassed when in test or loss of DC to RRCS Panel.)

Question 7

SLC Flowpath.

Answer 7

SLC Tank > 2 50% capacity pumps > 2 150% capacity SQUIB valves > Into ‘A’ CS Loop.

Question 8

What is the function of the heat trace?

Answer 8

To keep the pump heads and suction lines warm.

Question 9

What are the heater ratings and Power supplies?

Answer 9

40KW mixing, 282 MCC
10KW operating 252 MCC

Question 10

What indications do you have if a SLC pump fails to start?

Answer 10

RRCS Initiation Failure alarm illuminates 30 seconds after pump fails to start

Question 11

What operational difference is possible when operating SLC at the local control panels that is not possible remotely?

Answer 11

Operation of either local switch will START only the associated pump and will not FIRE either of the squib valves, or cause a RWCU system isolation.

Question 12

What is the TS Temperature limit associated with the SLC tank?

Answer 12

Temperature of the solution in the storage tank must be > 70oF as per Technical Specifications (prevents precipitation of sodium pentaborate)

Question 13

What automatic actuations are associated with the SLC pumps?

Answer 13

1. RRCS - Auto start
2. SLC low level(approximately 325 gallons gross or instrument zero) - Auto stop

Question 14

What is the SLC tank low level alarm?

Answer 14

4640 gallons net

Question 15

What is the TS flow limit associated with the SLC pumps?

Answer 15

41.2 gpm minimum

Question 16

What are the pump start conditions?

Answer 16

• RPV level -38”,
  OR
• RPV pressure 1071#,
  OR
• Manual,
  AND
• APRM power >4%
  OR
• APRM INOP ≥ 230 secs

Question 17

SLC pumps and RWCU isolation valves relationship.

Answer 17

• ‘A’ pump shuts F001
• ‘B’ pump shuts F004

Question 18

Why is moderator temp important to the SLCS?

Answer 18

Higher moderator temp requires less Boron concentration.

Question 19

Why is a proper valve lineup important?

Answer 19

Proper valve L/U prevents SLC dilution and air binding.

Question 20

Differences of pump operation from control room or local panel.

Answer 20

Running from local panel does not initiate SQUIB valves.

Question 21

What happens if SLC stops with RACS init. present?

Answer 21

SLC MAN OHA comes in.

Question 22

What happens when RRCS fails to initiate?

Answer 22

If it fails to initiate, OHA will come in 30 secs after it should have started.

Question 23

What is Cold Shutdown Boron Weight?

Answer 23

The weight of soluble boron required for injection to place the reactor in a cold (70°F) shutdown condition, at the most reactive time in core life. This is assumed to have been injected when there is 1100 gallons, (net), of solution left in the SLC tank.