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Feedwater Heater Drain Cooler Vent Valve Leakage
Eric Fulton
NPPD - Cooper Nuclear Station
January 2017
Started as small SJAE flow and temperature spikes
Then it got worse:
SJAE flow oscillations ~45 scfm
SJAE temperature oscillations up to 30°F
Condenser pressure oscillations ~0.15”Hg
Hotwell level oscillations 1-2”
Symptoms
\\cnspi \P.N085.V.CNS
51.881
CFM
\\cnspi \P.T106.V.CNS
105.88
DEGF
\\cnspi \P.T012.V.CNS
2.8231
HGAB
\\cnspi \P.F011.V.CNS
7.0446
FT
\\cnspi \P.F041.V.CNS
186.85
DEGF
SJAE B AIR FLOW SJ-EJTR B 1ST STAGE SUCT CONDENSER 1B ABS PRESS CONDENSR HOTWEL 1B LEVEL STM JETAIREJECT 1B DRAIN
23:00 22:00 21:00 20:00 19:00 18:00 17:00 16:00 15:00 14:00 10:00 9:00 8:00 7:00 6:00 5:00 4:00 3:00 2:00 1:00
7/3/2015 12:00:00 AMSJAE-B AR Temps
0
10
20
30
40
50
60
70
80
90
100
0
300
0
4
0
10
0
200
SJAE flow and temperature spiking began on July 3.
\\cnspi \P.N085.V.CNS
81.543
CFM
\\cnspi \P.T106.V.CNS
86.257
DEGF
\\cnspi \P.T012.V.CNS
2.4773
HGAB
\\cnspi \P.F011.V.CNS
7.0955
FT
\\cnspi \P.F041.V.CNS
188.87
DEGF
SJAE B AIR FLOW SJ-EJTR B 1ST STAGE SUCT CONDENSER 1B ABS PRESS CONDENSR HOTWEL 1B LEVEL STM JETAIREJECT 1B DRAIN
23:00 22:00 21:00 20:00 19:00 18:00 17:00 16:00 15:00 14:00 10:00 9:00 8:00 7:00 6:00 5:00 4:00 3:00 2:00 1:00
8/22/2015 12:00:00 AMSJAE-B AR Temps
0
10
20
30
40
50
60
70
80
90
100
0
300
0
4
0
10
0
200
By August 22, it had degraded to this!
Feedwater heater drain cooler vents return to main condenser through SJAE intercondenser loop seal drain
Vents are normally closed, only opened for a few minutes during startup
Not a problem unless the valves leak by!
Investigation
Feedwater HeaterDrain CoolerVents (open duringstartup only)
Feedwater HeaterDrain CoolerVents (open duringstartup only)
Main Condenser
From FWHDrain CoolerVentsSJAE Drain
Closed this normally open valve to isolate drain cooler vents from SJAE
\\cnspi \P.N085.V.CNS
51.011
CFM
\\cnspi \P.T106.V.CNS
106.63
DEGF
\\cnspi \P.T012.V.CNS
2.5113
HGAB
\\cnspi \P.F011.V.CNS
6.9943
FT
\\cnspi \P.F041.V.CNS
185.89
DEGF
SJAE B AIR FLOW SJ-EJTR B 1ST STAGE SUCT CONDENSER 1B ABS PRESS CONDENSR HOTWEL 1B LEVEL STM JETAIREJECT 1B DRAIN
23:00 22:00 21:00 20:00 19:00 18:00 17:00 16:00 15:00 14:00 10:00 9:00 8:00 7:00 6:00 5:00 4:00 3:00 2:00 1:00
8/23/2015 12:00:00 AMSJAE-B AR Temps
0
10
20
30
40
50
60
70
80
90
100
0
300
0
4
0
10
0
200
Examined all drain cooler vent valves during next refueling outage
Installed temperature elements on piping downstream of each valve for periodic temperature monitoring
Corrective Actions
We didn’t pay much attention to these valves until this issue occurred
Your vents probably don’t connect to SJAE’s
Leakage costs $$$
There are better valve designs
Conclusion
Recommended