1. Water in Oil – Feedwater Pump Point Beach Nuclear Plant
Kelly Oetting
BOP System Engineer
FSRUG 2013 Conference
January 21-24, 2013

2. PBNP Water In Oil FW Pump
2011 Power Uprate
Westinghouse 2 – Loop PWR, Unit , Unit
17%
545 MWe to 637 MWe (1540 MWth to 1800 MWth)
Unit 2 – 120 Days (3/1/11 - 6/19/11)
Unit 1 – 75 Days (10/3/11 – 12/17/11)
Approximately 35 Major Modifications for Each Unit
New Feedwater Pumps and Motors (entire skid)

3. PBNP Water In Oil FW Pump
New Pump Skid

4. Pump & Motor Design Change Details
PBNP Water In Oil FW Pump
Pump & Motor Design Change Details
Feed Pump
Sulzer – CD/BBS
# Stages 1
Rated Speed
3600 rpm
Design Flow
9300 gpm
Design Head
2200 ft
Mini Recirc
4000 gpm
Feed Pump Motor
TECO
Horsepower
6200
3582 rpm

5. PBNP Water In Oil FW Pump
Each pump & motor skid has its own oil system (shaft driven pmp, backup AC pmp, 60 gal reservoir, duplex filter, 2 plate style heat exchangers)
Water first evident in motor bearing oil return sightglass after initial system startup (Unit 2 B FW pump only)
Problem initially thought to be residual water in oil system left over from startup testing event on Unit 2 B FW pump
Normal quarterly oil reservoir sampling did not identify water initially (oil samples taken from mid level of oil reservoir)
11 months after initial Unit 2 startup, start failure of Unit 2 B FW pump back-up AC lube oil pump, AC pump seizure thought to be linked to startup testing event (May 2012)
Sampling started to identify water in oil, as high as 2569 ppm

6. PBNP Water In Oil FW Pump
Monitoring plan implemented with increased frequency sampling
Periodic bleed and feed performed to reduce water content (one gal at a time approx. 45 gal total)
13 months after initial Unit 2 startup, start failure of Unit 2 A FW pump back-up AC lube oil pump triggered further investigation, by this time water now visible in all 4 FW pump motor oil sightglasses (July 2012)
11 months after initial Unit 1 startup, normal quarterly oil sample for Unit 1 B pump had estimated >10000 PPM water content (Nov 2012)
Monitoring plans and periodic bleed and feeds established for both Units
Very slow water ingress into the oil system – all 4 FW pumps
Water collecting in oil system low spots, not initially mixing with oil

7. Water In Motor Bearing Drain Sightglass
PBNP Water In Oil FW Pump
Water In Motor Bearing Drain Sightglass

8. Motor Bearing Housing Sightglass
PBNP Water In Oil FW Pump
Motor Bearing Housing Sightglass

9. PBNP Water In Oil FW Pump
Potential Sources
Oil Coolers (oil cooled by condensate) Refuted – Plate style heat exchangers & heat in-service HX swapped
Seal Water Supply – seal water migrating past INPRO oil seals a. Water leaking past clamping rings b. Water migrating along the shaft c. Water leaking past INPRO oil seals d. Water possibly being drawn into oil system due to differential pressure across oil seal

10. PBNP Water In Oil FW Pump
Throttle Injection

11. PBNP Water In Oil FW Pump
OIL System

12. PBNP Water In Oil FW Pump
Changes implemented by Sulzer were a defense in depth approach
Replace original oil seals (INPRO) with different design (Isomag), both DE and NDE – Primary Solution
Improve oil drain chamber venting (replace current air release filter with improved vent/filter each end)
Improve seal water drain chamber venting (shorten piping & add vent/filter each end)
Improve secondary leak-off chamber venting (add additional vent/filter each end)
Add a groove and drain back notch to the seal labyrinth stator to help deflect water away from the oil seals
Remove insulation from the pump end cover faces
Plug jacking bolt holes of the labyrinth rotor

13. Original INPRO Oil Seal
PBNP Water In Oil FW Pump
Original INPRO Oil Seal

14. New John Crane Isomag Magnum-S Seal
PBNP Water In Oil FW Pump
New John Crane Isomag Magnum-S Seal

15. Original Bearing Housing Oil Rite Vent Plug
PBNP Water In Oil FW Pump
Original Bearing Housing Oil Rite Vent Plug

16. Original Bearing Housing Oil Rite Vent Plug
PBNP Water In Oil FW Pump
Original Bearing Housing Oil Rite Vent Plug

17. New Bearing Housing Vent ¾” Airmaze Breather – Metal Screen
PBNP Water In Oil FW Pump
New Bearing Housing Vent ¾” Airmaze Breather – Metal Screen

18. New Bearing Housing Vent (Airmaze)
PBNP Water In Oil FW Pump
New Bearing Housing Vent (Airmaze)

19. Original Seal Drain & Secondary Leak-Of Chamber Drain Venting
PBNP Water In Oil FW Pump
Original Seal Drain & Secondary Leak-Of Chamber Drain Venting

20. Secondary Leak-Off Chamber Leak-Off Drain – Before Modification
PBNP Water In Oil FW Pump
Secondary Leak-Off Chamber Leak-Off Drain – Before Modification

21. New Seal Drain & Secondary leak-Off Chamber Drain Venting
PBNP Water In Oil FW Pump
New Seal Drain & Secondary leak-Off Chamber Drain Venting

22. Secondary Leak-Off Chamber Leak-Off Drain – After Modification
PBNP Water In Oil FW Pump
Secondary Leak-Off Chamber Leak-Off Drain – After Modification

23. PBNP Water In Oil FW Pump
No Water In SIghtglass