RHR

Question 1

What are the RHR pump trips?

Answer 1

• Overcurrent/Overload
• Loadshed
• Lo-Lo RWST (9%) w/ RWST suction not fully closed

Question 2

What are the interlocks associated with opening IMO-310/320 (RHR Suction from RWST)?

Answer 2

Train specific

• RHR Suction from Recirc (ICM-305/306) Closed
• RHR to Upper Spray (IMO-330/331) Closed
• RHR to CCP/SI Suction (IMO-340/350) Closed

Not on Recirc, RHR Spray or Piggy Backing

Question 3

What are the interlocks associated with opening IMO-305/306 (Recirc Sump suction valve)?

Answer 3

Train specific
- RHR Suction from RWST (IMO-310/320) Closed
- RWST to CTS (IMO-215/225) Closed

No longer taking suction from RWST for RHR or CTS

Question 4

What is the interlock associated with opening IMO-128 and ICM-129 (Loop 2 HL RHR suction valve)

Answer 4

RCS pressure < 411 on Loop 1 / Loop 2 WR Press
- (NPS-122 gives signal to IMO-128 from RCS WR Loop 1 Pressure)
- (NPS-121 gives signal to ICM-129 from RCS WR Loop 2 Pressure)

Question 5

What are the interlocks associated with opening IMO-340/350 (RHR HX to CCP suction)?

Answer 5

Train specific
- RHR Suction from Recirc Sump (ICM-305/306) Open
- SI Recirc to RWST (IMO-262/263) Closed (with Ctrl Pwr on)

Ensures that water cannot be transferred from Recirc Sump to RWST

Question 6

What are the interlocks associated with IMO-330/331 (RHR spray valves)?

Answer 6

Train Specific
RHR Suction from Recirc Sump (ICM-305/306) open

Must be on Recirc Sump to use RHR Spray & 50 mins after accident

Question 7

What are the key flows for the RHR pump recirc valve operation?

Answer 7

Unit 1 Opens at 820 gpm and Closes at 1335 gpm
Unit 2 Opens at 900 gpm and Closes at 1500 gpm

Question 8

What does Hot Leg recirc do for the RCS?

Answer 8

Prevents boron precipitation

Question 9

What are the pressures that the RHR safety valves lift?

Answer 9

• RHR Suction Safety 450 psig
• Discharge Safeties - 600 psig
• Cooldown Line Safety - 600 psig

Question 10

When is RHR Spray used?

Answer 10

When there has been a failure of the CTS system
(< 2 CTS pumps are running when required)

Question 11

What is the Normal Cooldown flowpath for RHR?

Answer 11

Suction fron Loop 2 HL through Hx (IRV-310/320) and Hx Bypass (IRV-311) valves, thru discharge cross ties (IMO-314/324) valves and the out thru ICM-111 to Loop 2 and 3 CLs (Thermal Sleeves)

Preferred flow path when RCS temp > 200°F

Question 12

What is the ECCS lineup for RHR (Cold Leg Injection)?

Answer 12

• RHR Pumps take suction from RWST through Hx with Discharge crossties IMO-314/324 Open to all 4 Cold Legs

No valves need to re-position

Question 13

What is the Hot Leg Recirc flow path for RHR?

Answer 13

Injection switched to HLs by opening IMO-315/325 and IMO-316/326 are closed (Must be closed first and SI pumps must be shut off due to recircs being closed)

Question 14

Where does IRV-300 discharge to and where does it tap off the RHR system??

Answer 14

• Discharges to Inlet of the LD Hx
• Taps off after the RHR Hx before IRV-310/320

Question 15

What will auto start the RHR Pumps?

Answer 15

Train specific SI

Question 16

When is RHR placed into service after a Rx Shutdown?

Answer 16

When pressure is ~400 psig and temperature is < 350°F

Question 17

Why is there a minimum time of 5.5 hours after the accident before doing Hot Leg Recirc?

Answer 17

Avoid core uncovery due to boil off

Question 18

Why must you close RHR Loop Injection Valves prior to aligning RHR Spray?

Answer 18

Prevents RHR Pumps from running out

Question 19

In reagards to IMO-128 and ICM-129, ____ valve goes to ____ instrument, which goes to ____ Loop. (insert “Even” and/or “Odd” as applicable)

Answer 19

Even valve goes to even instrument, which goes to odd loop

Or

Odd valve goes to off instrument, which goes to even loop

Question 20

Can we run BOTH RHR Pumps at reduced inventory?

Answer 20

NO!!
We can only run 1 becaues we could cause air entrainment at Loop 2 suction due to vortexing

Question 21

On a SI, what does the CCW outlet from the RHR Hx throttle to?

Answer 21

3000-3500 gpm

Question 22

What is the weak RHR pump is protected by?

Answer 22

RHR Hx discharge check valve (Still has recirc flow)

Question 23

The following plant conditions exist:

• IMO-320, West RHR Pump Suction - closed
• IMO-390, RHR Pumps Suct from RWST - closed
• IMO-128 and ICM-129, RHR Returns from Hot Leg 2 - open
• ICM-306, Recirc Sump to West RHR/CTS Pumps - closed
• IMO-331, West RHR Spray to Upper Containment - closed
• IMO-350, SI Pump Suction from West RHR Heat Exchanger - closed
• RWST level is 7% and stable

Assuming electrical power is available, IMO-320 _______ be opened because _______.

A. can, IMO-390 & ICM-306 are closed.

B. cannot, RWST level is too low.

C. can, ICM-306, IMO-331 & IMO-350 are closed.

D. cannot, IMO-128 & ICM-129 are open.

Answer 23

C. can, ICM-306, IMO-331 & IMO-350 are closed

Question 24

While shifting to cold leg recirc during a LOCA, IMO-350, SI Pump Suction from West RHR Hx, will NOT open.

Which ONE of the following conditions must be established to allow IMO-350 to be opened?

A. IMO-361 and IMO-362, SI Pump Suction Cross-Ties to CCP - OPEN

B. IMO-320, West RHR pump Suction - OPEN

C. IMO-262 or IMO-263, SI Pumps Recirc to RWST - CLOSED

D. IMO-261, SI pump Suction From RWST - CLOSED

Answer 24

C. IMO-262 or IMO-263, SI Pumps Recirc to RWST - CLOSED

Question 25

What does the RHR Suction Safety support?

Answer 25

LTOP

Question 26

What is the purpose of Hot Sleeve Vent Fans?

Answer 26

Cool concrete to prevent dryout

Question 27

What is the flowpath for RHR Cold Leg Recirc?

Answer 27

Suction swaps from RWST to Recirc Sump, Discharge cross tie valves IMO-314/324 closed. Going to CL Loops 1-4.