Lgs Ilt - Rhr

Front 1

List the ratings, capacity, and power supplies of the RHR pumps.

Back 1

- RHR Pumps
- Multistage (4) vertically mounted centrifugal pumps.
- Powered from the 4160 VAC Safeguard Buses
A - D11 (D21)
B - D12 (D22)
C - D13 (D23)
D - D14 (D24)
- Pumps are rated for 33% capacity each, 10,000 gpm at 260 psig. (TECH SPEC – 10,000 gpm at 20 psid between RPV and primary containment)
- Pump Shaft is mechanically sealed with seal cooling water from the discharge of the pump via a cyclone separator.
- The pump motors are air cooled by the ventilating system and the motor oil coolers.
- Design pressure for the pump suction is 220 psig, with a temperature range from 40° to 360°F. Design pressure for the pump discharge is 500 psig. The bases for the design temperature and pressure are maximum shutdown cut-in pressures and temperature, minimum ambient temperature, and maximum shut-off head.

Front 2

Summarize how the following systems/components support the operation of the RHR System:
a. 4KV Distribution System

Back 2

- Safeguard buses supply power to associated divisions RHR Pump
- Loss of a 4KV safeguard bus will result in the associated RHR pump being inoperable.

Front 3

Summarize how the following systems/components support the operation of the RHR System:
RHR Service Water System

Back 3

- Provides Cooling Water flow to the RHR Heat Exchangers
- Loss of RHR Service Water prevents cooling of the primary containment.
- Ultimate heat sink valves tie into "B" loop of RHR on Unit 1 and "A" loop on Unit 2.

Front 4

Summarize how the following systems/components support the operation of the RHR System:c. Suppression Pool

Back 4

- Suction taken from the suppression pool via pump suction strainers (Suction Valves - F004)
- Suppression Pool Level: LPCI has the capability to lower suppression pool level in the event of a pipe break. If this occurs the LPCI pump must be secured. If pipe break is above suppression pool level, tripping the pump will stop the leak. If break below pool water level the RHR room would fill with water until the levels equalize.
- Suppression Pool level will drop about 2 feet following a LOCA due to water collecting in drywell. Closing F004A-D may stop leak.

Front 5

Summarize how the following systems/components support the operation of the RHR System: d. Keep Fill System

Back 5

- Provided to maintain the RHR discharge piping full preventing injection delay and water hammer
- Both Keepfill system and condensate transfer system provide 100% Keepfill capacity.
- Loss of both systems may result in air accumulation in the discharge piping with resultant water hammer concerns if boundary valves leak.

Front 6

Summarize how the following systems/components support the operation of the RHR System:e. DC Distribution

Back 6

- Loss of DC power will:
- Prevent the RHR pumps from receiving LOCA start signals
- If already running, they will continue running. However, they will not change “modes” (i.e., If in Suppression Pool cooling, will not auto align to LPCI mode if DC is lost.)

Front 7

Summarize how the following systems/components support the operation of the RHR System:
f. Diesel Generators

Back 7

- Supply power to appropriate safeguards panel energizing the RHR pumps in event of loss of offsite power.

Front 8

Summarize how the following systems/components support the operation of the RHR System: g. Service Water and Emergency Service Water

Back 8

- Provides cooling for the RHR pump motor oil coolers and RHR pump room unit coolers
- The ESW System provides 100% back up in the event of a loss of service water system.
- Loss of both SW and ESW would INOP RHR due to loss of cooling to pump motor oil and room unit coolers. The RHR pumps cannot operate without Motor Lube oil cooler.

Front 9

4. Summarize how the RHR System supports the operation of the following:
a. ADS

Back 9

- RHR system provides low-pressure pumps available signal to ADS initiation logic (125 psig RHR discharge pressure)
- Also provides adequate core cooling once ADS depressurizes the vessel.

Front 10

4. Summarize how the RHR System supports the operation of the following: b. Post accident recombiners

Back 10

- RHR system provides a small amount of flow for de-superheating the outlet flow of the recombiner.
- A loss of recombiner has no effect on RHR but a loss of RHR prevents recombiner operation.

Front 11

6. State the conditions and setpoints that will automatically initiate the LPCI mode of RHR.

Back 11

- LPCI Automatically initiates upon High drywell pressure (1.68 psig) AND low reactor pressure (455 psig); OR low reactor level (-129").
- One manual pushbutton is provided for each loop (A, B, C and D). To manually initiate LPCI the collar is rotated clockwise to the ARMED position and the button is depressed sealing in the signal. The system will respond as if it was an automatic initiation.

Front 12

Summarize the sequence of events that occur following the receipt of a LPCI initiation signal with and without offsite power available.

Back 12

- The emergency diesels start and will transfer over only if normal bus-power (off-site) is not available.
- The RHR pumps start
- With offsite power pumps C&D start immediately and A&B start 5 seconds later.
- Without off-site power each pump starts when the associated diesel output breaker shuts.
- Test return valves (F024A, B and F010A, B) close
- Suppression pool spray valves (F027A, B) close
- RHR heat exchanger bypass valves (F048A, B) receive an Open signal for three minutes to provide maximum LPCI flow.
- LPCI injection valves (F017A, B, C & D) will open when the differential pressure across the valve is less than 74 PSI.
- The DP interlock can result in un-intended injection and run out if the loop is already in another operating mode and RPV pressure is dropping or adjustments are made to discharge pressure

Front 13

Summarize the interlocks associated with the following: - RHR Heat Exchanger Bypass Valves (HV-F048A, B)

Back 13

- Manually operated from the control room, they are normally open to provide maximum flow for LPCI injection. Valves are installed to allow flow to bypass the heat exchanger for better temperature control.
- Valve receives an Open signal for three minutes following a LPCI initiation signal. If handswitch is taken to close, valve will cycle closed and then immediately reopen.
- F048A, B can be throttled three minutes after LPCI initiation.

Front 14

Summarize the interlocks associated with the following: - RHR Heat Exchanger Outlet Bypass Valve HV-C-51-*03A(B)

Back 14

- Operated by HIC *03A(B). in the MCR.
- Temperature indication XI-36-*01(2) at *0614 uses TE-51-*N004A (B) RHR Heat Exchanger Inlet as an indication of Rx coolant temperature. This indication is only valid with sufficient flow through the RHR heat exchanger. HIC-51-*03A(B) must be greater than 20% open to obtain an accurate temperature.

Front 15

Summarize the interlocks associated with the following: b. RHR pump suppression pool suction valves HV-F004A (B, C, D)

Back 15

- Manually operated from the control room
- Keylocked in the open position – These valves are not affected by any automatic circuitry.
- Interlocks prevent opening HV-F004A, B unless shutdown cooling valves (F006A,B) are fully closed.
- Interlocks prevent opening HV-F004C, D unless F067A, B fully closed.
- Interlocks do not apply to local manual operation of the valves. Prior to operating any suction valve manually the operator must be aware of system status and expected plant response.

Front 16

Summarize the interlocks associated with the following: c. RHR pump shutdown cooling suction valves (HV-F006A,B)

Back 16

- Manually operated from the Control Room
- Valves HV-F006 A&B will not open unless:
- Suppression Pool Suction (F004A&B) fully closed AND
- Containment Spray (HV-F027A (B)) and Test Return Valves (HV-F024A (B)) closed.
- Suction valves are normally closed and isolate the pump suction from the shutdown cooling supply line.

Front 17

Summarize the interlocks associated with the following: d. RHR pump start

Back 17

- RHR pumps are controlled from the control room using a STOP-AUTO-START Control Switch.
- The pump can be started manually using the control switch or automatically by a LOCA signal. The pumps are normally stopped manually.
- "A" RHR pump can be controlled from RSP. If RHR is being controlled via RSP, normal trips and interlocks are not enabled.

Front 18

Summarize the interlocks associated with the following: - RHR Pump Trips

Back 18

- Suction valve starts to shut. This includes associated F004A-D for LPCI Mode OR F006A(B), F008 or F009 in shutdown cooling mode, unless defeated by procedure to allow RHR-ADHR method.
- Control Switch to STOP
- Bus Lockout
- Bus undervoltage
- Phase overcurrent
- Ground fault

Front 19

Summarize the interlocks associated with the following: e. RHR minimum flow valves (F007A,B,C,D)

Back 19

- Each pump has an associated minimum flow bypass valve. These valves operate independently of all others, being controlled only by pump status and rate of pump discharge flow.
- Manually controlled from control room via AUTO-OPEN-CLOSE- PTS Switch. The "Auto" position permits valve to be opened or closed by the RHR logic circuit.
- Valves are normally opened manually at RPV pressures greater than 75 psig to ensure minimum flow during a LOCA condition.
- In "Auto" the pump starts and a 10 second time delay begins. If after 10 seconds flow is not greater than 1300 gpm, the valve will open. When flow is adequate the valve closes.
- Valve will close when flow is greater than 1300 gpm with no time delay.
- Valves provide minimum pump flow for cooling purposes by recirculating water to the suppression pool.

Front 20

Summarize the interlocks associated with the following: f. Test return valves (F024A, B), (F010A, B)

Back 20

- Test return valves F024A, B are motor operated throttle valves located in test return lines to the suppression pool for RHR pumps A&B.
- F024A, B operate in the same manner as Suppression Pool Spray Valves F027A,B.
- Test return valves F010A and B are located in the RHR Pump C and D return lines to the suppression pool.
- Close automatically when its respective loop LPCI initiation signal occurs.
- An LPCI initiation signal inhibits opening of the valve.

Front 21

g. LPCI injection valves (HV-F017A, B, C, D)

Back 21

- Motor operated valve completes flowpath for LPCI injection.
- Manual switch in Control Room
- "Auto" position allows valve to automatically open if
(1) Power available to respective pumps' 4 KV bus
(2) LPCI initiation signal present
(3) Low DP across valve (<74 psid)
- F017 can also be closed with a LOCA signal present)
- IF valve is stroking open, CLOSE: PULL-TO-STOP: CLOSE
- IF valve is full open, CLOSE

Front 22

9. List the conditions and/or actions required to establish the following flow paths and explain why they are needed. a. Drywell spray

Back 22

- Drywell Spray Isolation Valves (HV-F016A, B and 21A,B)
- F016A, B and F021A, B are motor operated valves, connected in series, used to isolate flow to the drywell spray nozzles.
- Manually controlled from the control room, they must be manually opened.
- Both valves can be opened at the same time if:
- High drywell pressure AND
- LPCI initiation signal AND
- Associated LPCI injection valve (F017) is shut.
- Valves F016A (B) and F021A (B) are interlocked so that only one can be opened at a time when there is no open permissive.

Front 23

9. List the conditions and/or actions required to establish the following flow paths and explain why they are needed.
b. Suppression chamber spray with a LPCI initiation signal present

Back 23

- Suppression Pool Spray Valves (HV-F027A, B)
- Motor operated valves located in lines to suppression pool spargers to isolate flow.
- Controlled manually from control room.
- Can be opened or closed manually at any time when there is NO LPCI initiation signal
- If open, the valve closes automatically upon LPCI initiation signal.
- Manual override circuit will allow valve to be opened if LPCI signal is present.

Front 24

9. List the conditions and/or actions required to establish the following flow paths and explain why they are needed. d. Shutdown cooling

Back 24

- Two conditions must be met to initiate shutdown cooling.
(1) Reactor level greater than 12.5"
(2) Reactor pressure less than 75 psig
- Flowpath is manually aligned.
- Suction is taken from Reactor recirculation loop "B" via F008 and F009.
- The flow is through F006A (B) into RHR pump.
- Flow is pumped through the RHR heat exchanger and on to the shutdown cooling return valve.
- F015A to recirculation loop A –OR– F015B to recirculation loop B.
- NOTE: HV-51-*F015A (B) will not close against pump shutoff head - the torque switches are set too low. However, when F009 and F008 begin to close on an isolation signal, the pump will trip, allowing the valves to close.
- The shutdown cooling flow path is isolated by a Group 2 isolation signal on
- Hi Reactor pressure (>75psig)
- Low Reactor level (<12.5")
The F009, F008, F015A, B valves close

Front 25

11. List the shutdown cooling isolations, including setpoints, and summarize the automatic functions that occur when an isolation signal is received while operating in the shutdown-cooling mode.
- Shutdown Cooling Valves (F008, F009, F015A, B)

Back 25

- Provided to isolate the flowpath to and from the reactor recirculation piping
- Manually controlled from the control room
- Normally maintained in closed position
- When switch in "auto" valves will close on a Group 2 isolation signal
- Low reactor level +12.5"
- Hi reactor pressure 75 psig.
- F008 has a backup open inhibit on 82 psig to satisfy Appendix R requirements
(Prevents opening only. Doesn't isolate).

Front 26

effects that a loss of shutdown cooling has on the following:
a. Reactor Pressure

Back 26

- With no heat rejection the reactor may pressurize. This effect would be immediate if coolant temperature is greater than 212°F. If less than 212°F, pressurization would not occur until heated to 212°F

Front 27

effects that a loss of shutdown cooling has on the following: b. Reactor Water Level

Back 27

- Loss of shutdown cooling would cause indicated water level to increase. (This is caused by equalizing the water level inside and outside the shroud)

Front 28

effects that a loss of shutdown cooling has on the following: c. Moderator and Vessel Temperatures

Back 28

- Both would increase if natural circulation established. Natural circulation is established by raising RPV water level to greater than 60". This level covers the moisture separator drains, which provide coupling between the inside and outside shroud area. If this is not achieved, water inside the shroud will be warmer than water outside. If this situation is allowed to continue the plant could change from OPCON 4 to OPCON 3. This warm-up/pressurization will occur with no indication until pressure begins to increase.

Front 29

effects that a loss of shutdown cooling has on the following: d. Recirculation loop temperature

Back 29

- With no forced circulation recirculation loop temperature indication cannot be used to determine average reactor coolant temperature.

Front 30

Summarize the effect that a loss of the following will have while operating in the shutdown-cooling mode.
a. AC Power

Back 30

- The pump would trip and the suction and return valves would remain open. Valves would have to be manually closed if power not restored. The pump and valves are safeguard powered so loss of more than one division would be required to create a problem.

Front 31

Summarize the effect that a loss of the following will have while operating in the shutdown-cooling mode. b. Recirculation System

Back 31

- Is shutdown when RHR is operating in shutdown cooling. The only failure that would affect SDC would be if the pipe fell off. In this case SDC would isolate on low RPV water level. For the affected pump to be used in the LPCI mode the operator would have to close the SDC suction valve (F006) and open the suppression pool suction valve (F004) before starting the pump.

Front 32

Summarize the effect that a loss of the following will have while operating in the shutdown-cooling mode. c. Reactor Water Level

Back 32

- SDC will isolate on low RPV water level (+12.5").

Front 33

Summarize the effect that a loss of the following will have while operating in the shutdown-cooling mode. d. RHR Service Water

Back 33

- Loss of RHRSW would render SDC ineffective at removing decay heat.

Front 34

15. Summarize the effect that a loss of LPCI will have on the following
a. Reactor water level and adequate core cooling

Back 34

- 3 of 4 LPCI pumps must inject into the RPV following a DBA LOCA to ensure adequate core cooling.

Front 35

15. Summarize the effect that a loss of LPCI will have on the following b. Suppression Pool Level

Back 35

- LPCI has the capability to lower suppression pool level in the event of a pipe break. If this occurs the LPCI pump must be secured. If pipe break is above suppression pool level, tripping the pump will stop the leak. If break below pool water level the RHR room would fill with water until the levels equalize.
- Suppression Pool level will drop about 2 feet following a LOCA due to water collecting in drywell. Closing F004A-D may stop leak.

Front 36

15. Summarize the effect that a loss of LPCI will have on the following
c. ADS

Back 36

- With no LPCI pumps in service both core spray pumps in either loop would have to be operating to satisfy ADS initiating logic.

Front 37

16. Summarize the effect that a loss of the following has on LPCI operation
a. AC electrical power

Back 37

- Prevent LPCI injection for the affected loop(s). Unless backed up by diesel generators.

Front 38

16. Summarize the effect that a loss of the following has on LPCI operation b. DC electrical power

Back 38

- To inject with LPCI the pump would have to be started at the breaker (by lifting the mechanical close lever)

Front 39

16. Summarize the effect that a loss of the following has on LPCI operation c. Diesel generators

Back 39

- With no power available to a RHR pump the pump cannot be used. If C or D RHR loops have power it may be desirable to crosstie to A or B loop to establish containment cooling.

Front 40

16. Summarize the effect that a loss of the following has on LPCI operation d. Keep Fill System

Back 40

- The RHR pumps can be placed in service to provide their Keepfill. Otherwise, LPCI injection times would be increased and water hammer may occur.

Front 41

16. Summarize the effect that a loss of the following has on LPCI operation e. RHR Service Water

Back 41

- The affected RHR loop would be ineffective at providing containment cooling. Additionally, injection from the ultimate heat sink is unavailable.

Front 42

16. Summarize the effect that a loss of the following has on LPCI operation f. Reactor level and pressure instrumentation

Back 42

- Depending on the failure mode automatic system actuation will occur or be prevented from occurring. Logic is 2 of 2 once and is shared with (comes from) the core spray logic of the same division.

Front 43

16. Summarize the effect that a loss of the following has on LPCI operation
g. ADS

Back 43

- LPCI will not be able to inject until RPV pressure is less than about 350 psig.

Front 44

16. Summarize the effect that a loss of the following has on LPCI operation h. Suppression Pool

Back 44

- The only source of water for LPCI. With no suppression pool, injection would be accomplished using the ultimate heat sink.

Front 45

16. Summarize the effect that a loss of the following has on LPCI operation i. Service Water

Back 45

- Provides motor lube oil cooling, and room cooling
- Can be backed up by ESW
- Motor lube oil cooling required for pump operation.

Front 46

17. Summarize the effect that a loss of Suppression Pool Cooling has on maintaining suppression pool temperature.

Back 46

- If unable to cool the suppression pool, temperature would increase requiring a plant shutdown. If loss of cooling capability occurred following a LOCA, containment venting for pressure control would eventually be necessary.

Front 47

18. Summarize the effect that a loss of the following has on the Suppression Pool Cooling Mode of RHR.
a. AC electric power

Back 47

- Pump would trip and valves would fail as is. Loop drain down to the suppression pool would occur due to SP cooling return valve being open (F024).

Front 48

18. Summarize the effect that a loss of the following has on the Suppression Pool Cooling Mode of RHR. b. Diesel generator

Back 48

- Would result in total loss of AC to the system if offsite power not available.

Front 49

18. Summarize the effect that a loss of the following has on the Suppression Pool Cooling Mode of RHR.c. Keep Fill System

Back 49

- Could result in a water hammer.

Front 50

18. Summarize the effect that a loss of the following has on the Suppression Pool Cooling Mode of RHR. e. Reactor level and pressure instrumentation

Back 50

- Must manually override LOCA signal to cool the suppression pool.

Front 51

19. Summarize the effect of a loss of drywell spray on drywell/suppression pool pressure, temperature and the effect of continued operation on drywell components with elevated temperature and pressure.

Back 51

- If unable to spray the drywell, containment temperature and pressure would continuously rise. Eventually the containment may require venting IAW T-200 or OT-101 depending on the event. Components (safety related) in the drywell are environmentally qualified up to 340°F. If temperatures exceed this value equipment degradation would eventually prevent proper operation. T-102 would direct RPV blowdown to prevent exceeding 340°F. This will effectively remove the heat source from the drywell. With RPV at 50 psig, saturation temperature is about 300°F.

Front 52

20. Summarize the effect that a loss of the following will have on the Drywell Spray mode of RHR.
a. AC electrical power

Back 52

- Must have power to operate pump and valves. If power lost while spraying, pumps would trip and valves fail as is. This would result in system draindown to suppression pool level.

Front 53

20. Summarize the effect that a loss of the following will have on the Drywell Spray mode of RHR. d. Drywell to Suppression chamber vacuum breaker

Back 53

- Drywell spray should not be attempted when the vacuum breakers do not work (under water). If unable to vent non-condensables back into the drywell a negative pressure could result due to steam condensation. Drywell floor differential pressure limits may also be exceeded.

Front 54

22. Summarize the effect that a loss of the following has on the Suppression Pool Spray mode of RHR. a. AC electrical power

Back 54

- Must have power to operate pump and valves. If power lost while spraying, pumps would trip and valves fail as is. This would result in system draindown to suppression pool level.

Front 55

22. Summarize the effect that a loss of the following has on the Suppression Pool Spray mode of RHR.d. Service Water

Back 55

- Loss of SW and ESW removes cooling water for RHR motor lube oil cooler and RHR pump room unit coolers.