Service Water

Question 1

What are the service water pump auto starts?

Answer 1

Reactor Level 2 (-38”)
Drywell Pressure (1.68#)
Low Flow in Loop (13,475 gpm) (Strainer D/P <1.0#)*(starts in the associated loop) [normal flow ~20,000gpm each]
RB Hi Rad (1x10-3uci/cc)
RF Hi Rad (2x10-3uci/cc)
Manual PCIS Initiation
LOP/LOCA Lvl 1 Sequencer (55 Sec) (Auto or Man)

Question 2

What starts with a service water pump start and how is it timed?

Answer 2

0 Pump Starts
10 Associated HX Outlet & Strainer Bkwsh Vlv Open
40 Discharge Valve begins to open to 4% at 1%/sec
70* Discharge Valve begins to open to 8% at 1%/sec
100* Discharge Valve begins to open to 100% at 1%/sec
~200 When Discharge Valve is full open, Spray Wash booster pump discharge valve opens

~230 When booster pump discharge valve is full open,
-Spray wash pump starts
-Traveling screen starts after pump starts

Question 3

What are the SW cooling to RACS isolations and when do they isolate?

Answer 3

RACS Isolations (2203, 2204, 2207, 2346)
Reactor Level 1 (-129”)
Drywell Pressure (1.68#)
RACS Room Flooded (1”)
A Level Switch – Isolates HV-2203 ‘A’ SSWS loop to RACS isolation& Gives OHA
B Level Switch – Isolates HV-2204 ‘B’ SSWS loop to RACS isolation & Gives OHA
C Level Switch – Isolates RACS HX In/Out Vlvs & No OHA

Question 4

What is the timing sequence for the service water discharge valves

Answer 4

After open signal;
40 seconds later - valve starts to open to 4%( + “x” secs to get to 4%)
30 seconds later - valve starts to open to 8% (+ “X” secs ot get to 8%)
30 seconds later - valve starts to open to 100% (+ “x” secs to get to 100%)
Valve stroke (including timer pauses) is 155.5 – 210.3 secs

Question 5

When operating in Auto what are the automatic functions of the traveling water screen?

Answer 5

Start:
* SSW Pump Discharge Valve is 100% open
* Spray Water Booster Pump Discharge Valve is 100% open
* Spray Water Booster Pump running
* Level differential across the TWS is < 10 “

Level differential is > 10 “ - Shift to Fast
Level differential is < 6 “ for 15 min - Shift to Slow

Question 6

What is the normal speed for the TWS and what is the default speed on a loss of air?

Answer 6

Normally in slow speed.
Default to fast speed on a loss of air.

Question 7

What permissives must be met in order to inject Sodium Hypochlorite into SSW?

Answer 7

a) No low-low storage tank level.
b) One of the two tanks must be selected.
c) The discharge valve for the tank in service must be fully open.
d) The discharge valve for the tank that is not in service must be fully closed.
e) No high chlorine concentration.
f) No low-low dilution water flow.

Question 8

What are the automatic trips for the SSW pumps?

Answer 8

Overcurrent
Undervoltage

Question 9

When will the yard dumps open?

Answer 9

1. When in Auto at 8 psig SACS HX outlet pressure sensed at the pipe centerline
2. When in Auto manually opened by placing the keylock switch to on and then depressing the open PB.(should be done administratively at 85F river temp)
3. For a sudden flow blockage there are rupture disks in parallel with each yard dump - 60#

Question 10

What are the automatic functions of the Spray Water Booster pump?

Answer 10

1. Spray water booster pump discharge valve opens(initiated by the screen wash system being in auto and the ssw pump discharge valve being 100% open)
2. The Spray Water Booster Pump will stop and stop the TWS when its discharge valve is <100% open.(initiated by the ssw pump is taken out of service and its associated discharge valve are <100% open)

Question 11

Describe the operations of the service water dewatering pump.

Answer 11

The pump will trip automatically on a low level and, if in AUTO, will auto start on high level
NOTE: The pump control switch in AUTO bypasses the Drain Tank high level alarm. Switch is procedurally required to be left in the OFF position.

Question 12

If control is switched to the RSP, how will this affect the SSW system?

Answer 12

B and D SSW pumps will NOT auto start if control is transferred to the RSP.

Question 13

What occurs in the SSW system when a LOCA signal is received?

Answer 13

1. All four pumps run to provide flow through SACS HX
2. RACS HX isolates
3. Non-operating SSW pumps started by sequencer at T-55seconds

Question 14

What is the difference in operations of the of the SACS HX outlet valves between a LOP/LOCA and other auto pump start signals?

Answer 14

1. When in MAN the Hx outlet valve opens 10 seconds after its associated SSW pump starts from a LOCA or LOP signal.
2. When in MAN the Hx outlet valve will not open after an AUTO pump start from the following signals:
   1) –38” RPV Level(PCIS)
   2) Reactor Building HVAC Exhaust Radiation High (1x10-3 Ci/cc)(PCIS)
   3) Refuel Floor Exhaust Radiation High (2x10-3 Ci/cc)(PCIS)
   4) Low flow from pump in associated loop, (< 13,475 gpm corresponds to < 1.0 psid across strainer)

NOTE: HV-2371B and HV-2355B(B HX outlet valves) will not auto open/close if their control has been transferred to the RSP.

Question 15

What occurs in the SSW system when a LOP occurs?

Answer 15

1. All four pumps run to provide flow through SACS HX
2. SSW pumps started by sequencer at T-55 seconds

Question 16

Describe the backwash valve operations on a SSW strainer start.

Answer 16

The strainer is continually backwashed. The backwash valve opens 10 sec after start, and stays open until pump stops.

Question 17

What occurs on a RACS HX room flooding condition?

Answer 17

The cross tie valves and the RACS valves in the SSW system isolate