Provides the core coolant flow necessary to meet the thermal rating of the plant. Also functions as a method of controlling reactor power.

External pumps provide subcooled water from the downcomer (annulus) region to the jet pump inlet manifolds.

Swing bus: LC103/104:

MCC133B:

1. #11 Recirc pump suction valve (MO-2-43A);
2. #11 Recirc pump discharge valve (MO-2-53A);
3. RHR x-tie (MO-4085A);
4. RHR Loop A Discharge(s) to LPCI (MO-2012 and MO-2014);

MCC 143B:

1. #12 Recirc pump suction valve (MO-2-43B);
2. #12 Recirc pump discharge valve (MO-2-53B);
3. RHR x-tie (MO-4085B);
4.  RHR Loop B Discharge(s) to LPCI (MO-2013 and MO-2015)

"Affected loop flow will go to zero, and the operating loop may increase slightly. The operating loop's jet pump flow will increase and the idle loop will indicate some jet pump flow. The flow through the idle loop may be in the reverse direction (may not). Also, there is a high probability of entering the stability BUFFER region or EXCLUSION region of the power-to-flow map."

Entrance into a high power/low flow region of the power/flow map.

1. Maintain system pressure boundary and provide a discharge flowpath for LPCI injection into the vessel;
2. Vary the recirculation flow rate of reactor water through the core;
3. Provide drive flow for circulation of reactor water through the core;
4. Provide a flowpath for RHR shutdown cooling.

Under hot conditions, what is the limit of recirc pump head (in psid) for steady state operation?

Removed from the requirements 11/2008

143 psid

Removed from the requirements 11/2008

Limit: 30%

Interlock: 20% feedwater flow

1. For core power levels of 80% rated and above, the speed of the faster pump may not exceed 117% of the speed of the slower pump.
2. For core power levels below 80% rated, the speed of the faster pump may not exceed 130% of the speed of the slower pump."

"When in one pump operation, the idle pump SHALL NOT be started unless the active pump speed is reduced to less than 50% of rated speed."

Per B.01.04-05,

Loop Stratification: A temperature difference, in excess of 50 degrees F between a recirc loop and the RPV.

Vessel Stratification: 145 degrees F between the bottom head and the upper region of the vessel.

Do not exceed 55% (31.6 mega-lb/hr) core flow if power is less than 35%.

"Provided any reverse flow is subtracted from indicatd flow, there should be no change in recirc pump flow vs. speed, and core plate dP vs. core flow."

Above about 50-60% speed

"The direction of flow can be determined by varying the speed of the operating recirc pump. If speed is increased and indicated flow in the jet pumps on the idle side increases, flow is in the reverse direction.

NOTE: for reverse flow, the indicated flow should be multiplied by 0.95 to determine the actual reverse flow."

Recirc Pump motor current: 437 Amps

Recirc Pump motor winding temperature limit: 311 degrees F.

Pump must be shut down upon reaching 311 degrees.

MG Set drive motors and Recirc pump motors have the same starting limitations:

1. Two starts are allowed from ambient temperature.
2. One start is allowed from operating temperature.

NOTE: The motor can be assumed to have returned to operating temperature after 50 minutes idle time or 24 minutes running time, at which time another start is permisible.

NOTE: A "start" means the motor has come up to rated speed.

Recirc flow SHALL NOT be raised unless the coolant temperature difference between the bottom head region and upper region of the vessel is less than 145 degrees F.

An actual temperature difference greater than above requires reactor shutdown.

Scoop tube should be IMMEDIATELY reset by pressing the RESET button at C-04. However, there are instances when this action is not recommended (for instance, when scoop tube was locked by the operator)."

The volume between these two valves is required to be drained if both valves will be isolated for greater than 4 hours during normal operation.

The purpose for draining is to prevent the X-41 penetration/piping from being over-pressurized due to the expansion of water trapped in piping in the event of a LOCA while the penetration is isolated.

Section 3.4: RCS

Tech Spec 3.4.1: Recirculation Loops Operating

LCO 3.4.1: Two recirc loops with matched flows shall be in operation within the Normal Region of the power to flow map specified in the COLR;

OR

One recirc loop shall be in operation within the Normal Region of the power to flow map specified in the COLR and with the following limits applied when the associated LCO is applicable:

• LCO 3.2.1 ""APLHGR"", single loop operation limits specified in the COLR
• LCO 3.2.2, ""MCPR"", single loop operation limits specified in the COLR and
• LCO 3.3.1.1 ""RPS"" Function 2.a (APRM Flow Referenced Neutron Flux - High High),

Allowable Value of Table 3.3.1.1-1 is reset for single loop operation.

NOTE: Operation within the Stability Buffer Region of the power to flow map specified in the COLR is allowed provided the power distribution controls specified in the COLR are in effect.

APPLICABILITY: Modes 1 and 2.

CONDITION A: Operation within Stability Exclusion Region of the power to flow map specified in the COLR.

OR

Operation within the stability buffer region of the power to flow map specified in the COLR and the power distribution controls specified in the COLR not in effect.

REQUIRED ACTION A.1: Initiate action to restore operation to within the Normal Region of the power to flow map specified in the COLR.

COMPLETION TIME: Immediately.

Section 3.4: RCS

 Tech Spec 3.4.2: Jet Pumps

LCO 3.4.2: All jet pumps shall be OPERABLE;

APPLICABILITY: Modes 1 and 2.

Basis: An inoperable jet pump can increase the blowdown area and reduce the capability to reflood during a design basis LOCA.

1. Hi fluid oil temp (greater than 210 degrees F;
2. Lo lube oil pressure (27 psig with a 6 second time delay);
3. Pump suction valve (less than or equal to 90% open);
4. pump discharge valve less than 20-25% open (66 sec time delay on pump start);
5. low-low RPV water level;
6. LPCI loop selection logic;
7. MG generator lockout relay trip;
8. Auto transfer from 2R to 1R;
9. Drive motor bus undervoltage (w/ ~ 18 cycle time delay);
10. Local trip test switch in TRIP;
11. Control Switch taken to STOP

1. Generator field breaker open;
2. Lube oil pressure greater than or equal to 20 psig;
3. No generator lockouts;
4. No drive motor breaker trips actuated;
5. Recirc pump suction valve open;
6. Recirc discharge valve closed;
7. Drive motor breaker is racked in;
8. Control switch is taken to START.

1. Incomplete startup sequence
2. Drive motor feeder ground fault, negative sequence, or phase over-current
3. Generator neutral overvoltage
4. Generator pump differential current
5. Generator exciter field overcurrent
6. Generator overcurrent (a. 10 sec time delay if startup sequence is not complete, or no time delay if complete)
7. Generator field undervoltage only when: switch in normal after start AND field breaker closed AND start sequence complete.

Drive motor breaker trips, Generator field breaker trips.

NOTE: Recirc MG Generator lockout sends a trip signal to both the Drive motor breaker and the field breaker.

1. Drive motor bus undervoltage;
2. Low lube oil pressure (27 psig) with a 6 second time delay;
3. High-high lube oil temperature (> 210 degrees);
4. Speed control failure;
5. Speed control signal mismatch; 
6. Loss of power to scoop tube actuator
   • Y-20 is power supply
   • MCC-143 is normal supply to Y-20; if a transfer to MCC-133 occurs due to a loss of MCC-143, a (resettable) scoop tube lock will occur.
7. C-04 pushbutton

1. MG generator lockout trip;
2. Generator loss of field;
3. Low-low rx water level (-47") for 7.3 seconds;
4. High rx pressure (1135 psig);
5. Manual ATWS Initiation (C-05)

• MO-2-43 A/B;
• must be open to start;
• seal-in for both open and close signals;
• trip signal established when valve is less than 90% open.

For the RECIRC DISCHARGE valve:

1. State the valve number for RECIRC DISCHARGE
2. Its condition for pump start (open or closed),
3. When a seal-in signal is established (open and/or closed)
4. When a pump trip signal is established

1. MO-2-53 A/B;
2. closed to start;
3. seal-in on close signal only;
4. trip signal established if not >20-25% open 66 sec (and beyond) follwing pump start.

2.5% per second when lowering speed;

2.0% per second when raising speed.

• 11 Recirc MG Set Emergency LO pump
• 12 Recirc MG Set Emergency LO pump
• Main Steam Line Drain MO-2374
• RHR Shutdown Cooling Outboard (MO-2030)
• RWCU Inlet Outboard Isolation (MO-2398)
• RHR Discharge to Waste Surge Tank (MO-2407)

Each MG set has one AC Lube Oil pump from MCC-132 and one from MCC-122