Reactor Water Cleanup - 1.0

Question 1

What is HV-F033 in the RWCU system and what is its purpose?

Answer 1

The blow down control valve is used to control the blow down flow rate from the RWCU System to either the main condenser or liquid radwaste equipment drain processing system

Question 2

What is the concern with the loss of a single RWCU pump when in two pump operations?

Answer 2

Loss of a RWCU pump, when in two pump operation, can cause pump run out. Flow must be reduced immediately by throttling HV-F042 Regen HX Return Isolation OR closing HV-F044 Filter Demin Bypass (if open) until Chemistry can remove a filter/demin from service.

Question 3

What are the conditions that will cause the RWCU pumps to trip?

Answer 3

• F001 or F004 not 100% open (11 sec TD).
• Low Flow <70 gpm w/ a 9 sec TD. This is bypassed for the first 15 mins on pump start.
• Hi motor temp 158°F w/ 10 sec TD.

Question 4

List Conditions that will isolate F033.

Answer 4

• Hi pressure (≥140 psig) downstream of valve to protect RW piping.
• Low pressure (≤5 psig) to prevent draining piping to RW.

Question 5

What are the RWCU common isolations(ie F001 and F004)?

Answer 5

1) -38” Reactor Water Level (NS4)
2) A RWCU pump room high ambient temperature (140F) (LDS via NS4)
3) B RWCU pump room high ambient temperature (140F) (LDS via NS4)
4) RWCU heat exchanger room high ambient temperature (140F) (LDS via NS4)- two points monitored.
5) RWCU pipe chase areas high ambient temperature(Room 4402(4505) 160F(135F))(LDS via NS4)
6) A ventilation high differential temperature (60F DeltaT) in any of the RWCU areas (LDS via NS4)
7) RWCU high differential flow 56.3 gpm after 45 second time delay (LDS via NS4)
8) Redundant Reactivity Control System actuation. [either “A” or “B” RRCS channel]

Question 6

What are the RWCU isolations specific to F001?

Answer 6

1) “A” NS4 manual isolation pushbutton armed and depressed
2) “A” SLC pump start
3) Loss of “A” RPS because it powers leak detection

Question 7

What are the RWCU isolations specific to F004?

Answer 7

1) “D” NS4 manual isolation pushbutton armed and depressed
2) “B” SLC pump start
3) Non-regenerative heat exchanger high outlet (F/D inlet) temperature (140F) (NS4)
4) Loss of “B” RPS because it powers leak detection

Question 8

What are the RWCU pump auto trips?

Answer 8

1) Inboard or Outboard primary containment isolation valve (HV-F001/F004) not 100% open
Both valves open is a start permissive
11 seconds TD to allow the filter hold pump
to start.
2) Low pump suction flow less than 70 gpm
9 second TD after the pump has been
running 15 minutes
3)High pump motor temperature 158oF
10 second TD

Question 9

Are there any RWCU pump start interlocks?

Answer 9

Both F001 and F004 must be open to start

Question 10

List precautions associated with blowdown operations.

Answer 10

• Raising blowdown flow will raise NRHX temp.
• Never open F034 & F035 at the same time. This connects the MC with RW piping and will degrade vacuum.
• Only send filtered water to the MC.

Question 11

What must be maintained in HSBY/SHUTDOWN?

Answer 11

RWCU system flow and temp (<434°F) must be maintained to prevent thermal shock to the feed nozzles. Bypass valves can be opened if necessary.

Question 12

What are the common F001 & F004 isolation signals?

Answer 12

• RPV -38”.
• RWCU pump room 140°F.
• HX room 140°F.
• Room 4505 135°F.
• 4402 160°F.
• Vent differential temp between RWCU rooms 60°F.
• RWCU differential flow of 56.3 gpm w/ a 45 sec TD.
• RRCS, either channel will shut both valves.

Question 13

What are the isolation signals for F001?

Answer 13

• ‘A’ NS4 manual isolation PB armed and depressed.
• ‘A’ SLC pump start.
• Loss of leak detection (RPS A)
• Pressing power mon relay test

Question 14

What are the isolation signals for F004?

Answer 14

• ‘D’ NS4 manual isolation PB armed and depressed.
• ‘B’ SLC pump start.
• NRHX outlet 140°F.
• Loss of leak detection (RPS B)
• Pressing power mon relay test

Question 15

What does RACS cool in RWCU?

Answer 15

• The pumps
• NRHX.