Transcript Spent Fuel Pool Evaporative Losses Richard Conatser Calvert Cliffs Constellation Energy Group June 2004 Objectives  Review Calvert Cliffs experiences  Discuss pool evaporative loss equation  Discuss parameters.

Spent Fuel Pool
Evaporative Losses
Richard Conatser
Calvert Cliffs
Constellation Energy Group
June 2004
1
Objectives
 Review
Calvert Cliffs experiences
 Discuss pool evaporative loss equation
 Discuss parameters and variables
 Plant system interrelationships
 Accountability methods
 Review uncertainties in methods
2
Overview of Topics
 Introduction
 Analysis
for H-3 in main vent
 Methods for estimating evap losses
 ASHRAE Equation for evap losses
 System interrelationships, ventilation
 H-3 Correlation: SFP to Main Vent
 Conclusions
3
Introduction
 Evaporative
losses from SFP are large
 The SFP [H-3] is relatively high
 Evaporative loss can be estimated
 Evaporative losses exhaust via M/V
 H-3 surveillance is done on M/V
 Compare M/V H-3 to SFP evap losses
4
Sampling: H-3 in M/V
 Sample
M/V continuously
 40 cc/minute sample flow
 Desiccant cartridge collects H-3
 Silica gel is distilled each month
 Graph shows results
5
1-Nov-93
31-Jan-94
2-May-94
1-Aug-94
1-Nov-94
31-Jan-95
2-May-95
2-Aug-95
1-Nov-95
31-Jan-96
2-May-96
1-Aug-96
31-Oct-96
31-Jan-97
2-May-97
1-Aug-97
31-Oct-97
31-Jan-98
2-May-98
1-Aug-98
1-Nov-98
31-Jan-99
2-May-99
2-Aug-99
1-Nov-99
31-Jan-00
2-May-00
1-Aug-00
31-Oct-00
30-Jan-01
2-May-01
1-Aug-01
31-Oct-01
31-Jan-02
2-May-02
1-Aug-02
1-Nov-02
31-Jan-03
2-May-03
2-Aug-03
1-Nov-03
31-Jan-04
uCi/cc
H-3, U-1 Main Vent
1.00E-07
1.00E-08
1.00E-09
1.00E-10
1.00E-11
H-3, U-1, uCi/cc
1.00E-12
SFP Evaporation: Method 1
 Evap
can’t be measured directly
 Water is added to pool with hose
 Volume added is not measured
 Pool level recorded 2/day
 Assume pool level increase = evapaL
 Then calc evapaL
7
Spent Fuel Pool Evaporative Loss
Gallons
Based on SFP Level Increases Only
45,000
40,000
35,000
30,000
25,000
20,000
15,000
10,000
5,000
0
468 gpd avg. based
on highest reading
420 gpd avg. based
on black trend line
01-Jan-01
31-Jan-01
02-Mar-01
01-Apr-01
Method 1 Uncertainties
 Any
losses (not evap), add error
 RFP flood-up/open transfer tube
 Fuel Assy removal (500 gal/can)
 Fuel pool temp changes
 SFP leakage (1 liter/day)
 Chemistry sampling (20 gal/wk)
9
SFP Evaporation: Method 2
Calculate from standard equations
 ASHRAE Handbook
 Rough estimate of evaporation
 Vapor pressure of SFP water (Pw)
 Vapor pressure at dew point (Pa)
 Heat of vaporization of water (Hv)
 Then calc evapaF

10
ASHRAE Evap Equation

W=(A+BV)(Pw-Pa)/Hv
W = evap rate, lbm/hr per ft2
 V = air velocity above pool, mph
 Pw = Vapor pressure of SFP water
 Pa = Saturation vapor pres at dew point
 Hv = Heat of vaporization of water
 A, B = Constants, (for wind speed)

11
Adaptation of the ASHRAE equation for
evaporative losses from an open pool.
Fuel pool Temp F
Fuel pool Temp C
Air Temp F
Air Temp C
86
86
86
30
30
30
63
73
83
17.22222 22.77778 28.33333
V as feet/sec
A
B
V (mph)
Pw (inches Hg), 86 F
Pa (inches Hg)
Hv (BTU/lb)
0.293333 0.293333 0.293333
95
95
95
37.4
37.4
37.4
0.2
0.2
0.2
1.251969 1.251969 1.251969
0.57874 0.818898 1.137795
1044.98 1044.98 1044.98
W (lbm/hr/ft2)
Pool Surface sq ft
hour/day
Pounds/Gal
Gal/Pound
0.066023 0.042471 0.011197
2301.5
2301.5
2301.5
24
24
24
8.30063 8.30063 8.30063
0.120473 0.120473 0.120473
Pounds/Day
Evaporation Rate, gpd
3646.832 2345.915 618.4686
439
283
75
SFP Evaporation: Method 3
 468
gpd is 0.33 inches SFP per day!
 Reviewed typical SFP data
 Excluded RFO fuel transfers
 Excluded high temperature changes
 Excluded transcription errors
 The real evaporation rate appeared
13
02-Jun-03
03-May-03
02-Apr-03
03-Mar-03
31-Jan-03
01-Jan-03
01-Dec-02
01-Nov-02
01-Oct-02
01-Sep-02
02-Aug-02
02-Jul-02
02-Jun-02
02-May-02
02-Apr-02
02-Mar-02
31-Jan-02
31-Dec-01
01-Dec-01
31-Oct-01
01-Oct-01
01-Sep-01
01-Aug-01
02-Jul-01
01-Jun-01
02-May-01
01-Apr-01
02-Mar-01
30-Jan-01
31-Dec-00
01-Dec-00
gpd
SFP Level Change
Based on Selected Level Changes Over Short Periods of Time
600
500
400
300
200
100
0
SFP H-3
 Have
been trending (PC) since 1998
 Records prior to that are in vault
 SFP H-3 related to RCS H-3
 Next slide shows trend
15
1-Nov-93
31-Jan-94
2-May-94
1-Aug-94
1-Nov-94
31-Jan-95
2-May-95
2-Aug-95
1-Nov-95
31-Jan-96
2-May-96
1-Aug-96
31-Oct-96
31-Jan-97
2-May-97
1-Aug-97
31-Oct-97
31-Jan-98
2-May-98
1-Aug-98
1-Nov-98
31-Jan-99
2-May-99
2-Aug-99
1-Nov-99
31-Jan-00
2-May-00
1-Aug-00
31-Oct-00
30-Jan-01
2-May-01
1-Aug-01
31-Oct-01
31-Jan-02
2-May-02
1-Aug-02
1-Nov-02
31-Jan-03
2-May-03
2-Aug-03
1-Nov-03
31-Jan-04
uCi/cc
H-3, RCS and SFP, CCNPP
10
1.00E+01
1
1.00E+00
0.1
1.00E-01
0.01
1.00E-02
U1 RCS H-3
U2 RCS H-3
SFP H-3 uCi/cc
0.001
1.00E-03
1-Nov-93
31-Jan-94
2-May-94
1-Aug-94
1-Nov-94
31-Jan-95
2-May-95
2-Aug-95
1-Nov-95
31-Jan-96
2-May-96
1-Aug-96
31-Oct-96
31-Jan-97
2-May-97
1-Aug-97
31-Oct-97
31-Jan-98
2-May-98
1-Aug-98
1-Nov-98
31-Jan-99
2-May-99
2-Aug-99
1-Nov-99
31-Jan-00
2-May-00
1-Aug-00
31-Oct-00
30-Jan-01
2-May-01
1-Aug-01
31-Oct-01
31-Jan-02
2-May-02
1-Aug-02
1-Nov-02
31-Jan-03
2-May-03
2-Aug-03
1-Nov-03
31-Jan-04
uCi/cc
H-3, Main Vent
1.00E-07
1.00E-08
1.00E-09
1.00E-10
1.00E-11
H-3, U-2 M/V
H-3, U-1 M/V
1.00E-12
1-Nov-93
31-Jan-94
2-May-94
1-Aug-94
1-Nov-94
31-Jan-95
2-May-95
2-Aug-95
1-Nov-95
31-Jan-96
2-May-96
1-Aug-96
31-Oct-96
31-Jan-97
2-May-97
1-Aug-97
31-Oct-97
31-Jan-98
2-May-98
1-Aug-98
1-Nov-98
31-Jan-99
2-May-99
2-Aug-99
1-Nov-99
31-Jan-00
2-May-00
1-Aug-00
31-Oct-00
30-Jan-01
2-May-01
1-Aug-01
31-Oct-01
31-Jan-02
2-May-02
1-Aug-02
1-Nov-02
31-Jan-03
2-May-03
2-Aug-03
1-Nov-03
31-Jan-04
uCi/cc
H-3, U-1, RCS, Main Vent, and SFP
1.00E-07
1.00E+01
1.00E-08
1.00E+00
1.00E-09
1.00E-01
1.00E-10
1.00E-02
H-3, U-1 M/V
SFP H-3 uCi/cc
U1 RCS H-3
Poly. (SFP H-3 uCi/cc)
Poly. (U1 RCS H-3)
Poly. (H-3, U-1 M/V)
1.00E-11
1.00E-03
1-Nov-93
31-Jan-94
2-May-94
1-Aug-94
1-Nov-94
31-Jan-95
2-May-95
2-Aug-95
1-Nov-95
31-Jan-96
2-May-96
1-Aug-96
31-Oct-96
31-Jan-97
2-May-97
1-Aug-97
31-Oct-97
31-Jan-98
2-May-98
1-Aug-98
1-Nov-98
31-Jan-99
2-May-99
2-Aug-99
1-Nov-99
31-Jan-00
2-May-00
1-Aug-00
31-Oct-00
30-Jan-01
2-May-01
1-Aug-01
31-Oct-01
31-Jan-02
2-May-02
1-Aug-02
1-Nov-02
31-Jan-03
2-May-03
2-Aug-03
1-Nov-03
31-Jan-04
uCi/cc
H-3, U-2, RCS, Main Vent, and SFP, CCNPP
1E-08
1E+1
1E-09
1E+0
1E-10
1E-1
1E-11
1E-2
H-3, U-2 M/V
SFP H-3 uCi/cc
U2 RCS H-3
Poly. (H-3, U-2 M/V)
Poly. (SFP H-3 uCi/cc)
Poly. (U2 RCS H-3)
1E-12
1E-3
1-Nov-93
31-Jan-94
2-May-94
1-Aug-94
1-Nov-94
31-Jan-95
2-May-95
2-Aug-95
1-Nov-95
31-Jan-96
2-May-96
1-Aug-96
31-Oct-96
31-Jan-97
2-May-97
1-Aug-97
31-Oct-97
31-Jan-98
2-May-98
1-Aug-98
1-Nov-98
31-Jan-99
2-May-99
2-Aug-99
1-Nov-99
31-Jan-00
2-May-00
1-Aug-00
31-Oct-00
30-Jan-01
2-May-01
1-Aug-01
31-Oct-01
31-Jan-02
2-May-02
1-Aug-02
1-Nov-02
31-Jan-03
2-May-03
2-Aug-03
1-Nov-03
31-Jan-04
uCi/cc
H-3, U-2 Main Vent and SFP
1.00E-08
1.00E-01
1.00E-09
1.00E-02
1.00E-10
1.00E-03
1.00E-11
1.00E-04
H-3, U-2 M/V
SFP H-3 uCi/cc
Poly. (H-3, U-2 M/V)
Poly. (SFP H-3 uCi/cc)
1.00E-12
1.00E-05
Comparison: Preliminary
Results
SFP Evaporative Losses vs Reg Guide 1.21 Unit-1 Tritium Values
Month
Jan
Feb
Mar
Quarter
Evaporation estimate, gpd
Evaporation estimate, gal/month
Evaporation estimate, liters/month
Tritium in SFP uCi/cc
Curies Evaporated from SFP, estimate
H-3, Ci, from Reg Guide 1.21 Report
Difference, Ci
Percent Difference
419
438
522
460
12977
12263
16191
41432
49119
46416
61284
156819
1.94E-02 1.94E-02 1.94E-02 1.94E-02
0.953
0.900
1.189 3.04E+00
0.503
0.642
0.422 1.57E+00
-0.450
-0.258
-0.767 -1.47E+00
-47%
-29%
-65%
-48%
21
Final Results
SFP Evaporative Losses vs Reg Guide 1.21 Unit-1 Tritium Values
Month
Jan
Feb
Mar
Quarter
Evaporation estimate, gpd
Evaporation estimate, gal/month
Evaporation estimate, liters/month
Tritium in SFP uCi/cc
Curies Evaporated from SFP, estimate
H-3, Ci, from Reg Guide 1.21 Report
Difference, Ci
Percent Difference
283
283
283
283
8773
7924
8773
25470
33206
29992
33206
96404
1.94E-02 1.94E-02 1.94E-02 1.94E-02
0.644
0.582
0.644 1.87E+00
0.503
0.642
0.422 1.57E+00
-0.141
0.060
-0.222 -3.00E-01
-22%
10%
-34%
-16%
22
Comparison of Main Vent H-3 and SFP Evaporation
1.8
Curies Evaporated From SFP
1.6
H-3, Ci/month, U1 only
1.4
Curies From Reg Guide 1.21 Both Units
SFP evaporation
rate = 283 gpd
1.0
0.8
0.6
0.4
0.2
January 2001 - April 2002
Apr
Mar
Feb
Jan
Dec
Nov
Oct
Sep
Aug
Jul
Jun
May
Apr
Mar
Feb
0.0
Jan
Curies of Tritium
1.2
Update with 2003 Data
 12
Ci H-3 from site (2 units) in 2003
 9.54 Ci discharged from U-1 M/V
 U-1 M/V average = 0.795 Ci/month
 Expected SFP = From 0.6 to 0.7 Ci/month
 Excellent agreement
24
Conclusions
 Selection
of evaporation rate is critical
 Validate the evaporation calculations!
 Use the ASHRAE equation (it’s easier…)
 Tweak evap rate for seasonal variations
 Compare M/V H-3 to SFP evap yearly
 Comparison on monthly basis not difficult
25
Questions?
26