ML072970375
| ML072970375 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 07/18/2007 |
| From: | English C, Noggle J Entergy Nuclear Operations, NRC/RGN-I/DRS/PSB2 |
| To: | Noggle J NRC/RGN-I/DRS/PSB2 |
| References | |
| FOIA/PA-2007-0324 | |
| Download: ML072970375 (7) | |
Text
J~mes N6ggIe - FW: H-3 Balance for Unit 1 - minor revisions Page 1 I Wmes _Nýgg!q -_Fý; H-for Unit 1 - minor revisions Page 1 1 From:
To:
Date:
Subject:
"Eng'Ljh, Christopher C" <cengli2@entergy.com>
<jdn@nrc.gov>
07/18/2007 10:14:05 AM FW: H-3 Balance for Unit 1 - minor revisions
- Thanks, Chris English From: Dennis Quinn [1]
Sent: Friday, April 20, 2007 7:26 AM To: Adler, Joseph J.; mbarvenik@gza.com; Hinrichs, Gary H; Hollenbeck, Peter; Donahue, Patrick J; Gray, Dara F; Sandike, Steven Richard; Mayer, Donald M; English, Christopher C
Subject:
H-3 Balance for Unit 1 - minor revisions I made some minor revisions to the H-3 balance, mostly to add two months of data that I didn't have in there. The basic answer hasn't changed...
there is about 3 times as much, H-3 being collected from the drain systems than is being leaked from Ul West Pool. (Uncertainty - plus or minus about 60%). Also, I put in some possible reasons for the imbalance, namely:
1.
2.
Contributions from Unit 2 area More leakage than expected from Unit 1 It's important for those who know more than I do about the tracer tests and the latest groundwater results (i.e. - everyone on the addressee list) comment on the "Results" section, or follow up with a separate document that states the IPEC "best guess" as to what is happening.
Dennis Dennis Quinn, CHP DAQ, Inc.
845-223-1960 Office 845-223-1099 Fax
[b)(6)
Information in this record was deleted in accordance with the Freedon of Information Act.
Exemptions FOINPA 7
C-A-I4s5-
Tritium Mass Balance for Unit 1 Spent Fuel Pool - 2006 Draft Tritium Mass Balance for Unit 1 Spent Fuel Complex The purpose of the tritium mass balance is to determine if the amount of water estimated to be leaking from the Unit I Spent Fuel Complex (Ul SFP) can account for the amount of tritium being collected in groundwater and surface water drainoff nearby. Specifically, the tritium balance compares the nominal leakage rate from Ul SFP (65 gallons per day, gpd) at the measured tritium concentration in the West Pool to the total activity collected in the Sphere Foundation Drain Sump (SFDS) and the North Curtain Drain (NCD).
Parameters Calculations were performed using the best available data, including the following parameters:
- Unit I West Pool tritium activity: Samples have been collected and counted for tritium on a regular basis starting in 2003, and this evaluation uses the available monthly data from 2006.
- Unit I West Pool leakage rate is based on laser measurement readings of pool height and reviews of operational data including water additions and water removal.
North Curtain Drain tritium activity: These composite samples were collected and counted at least monthly during 2006.
- North Curtain Drain Volume: Volume was determined flow totalizer readings in 2006, and the monthly volumes were used in this evaluation.
- Sphere Foundation Drain Sump tritium activity: These composite samples were collected and counted at least monthly during 2006.
- Sphere Foundation Drain Sump Volume: Volume was determined flow totalizer readings in 2006, and the monthly volumes were used in this evaluation.
The methodology involved performing calculation of monthly data as follows:
- UI SFP H-3 x 65 gallons per day = total H-3 released Uncertainties There are uncertainties in each of the parameters used in this calculation, and the magnitude of these uncertainties is estimated.
Unit I West Pool o Unit 1 West Pool tritium activity: Tritium activity is well above the minimum detectable concentration and counting errors are low. There is some uncertainty related to the representative nature of the sample; however, this uncertainty is also expected to be low based on pool mixing due to water treatment. The estimated uncertainty (Icy value) is 15%.
o Unit 1 West Pool leakage: The value of 65 gallons per day leakage from the Ul SFP is based on a review performed in 2006, and is considered a long-term average given the existing pool conditions. Although the measurements are accurate, the changes in water level in other pools can Page 1
Tritium Mass Balance for Unit 1 Spent Fuel Pool - 2006 Draft affect the apparent leak rate from the West Pool; therefore the uncertainty in the leakage rate is estimated at 60%.
o Activity release rate from pool: The uncertainty in the activity release rate (uCi/month) is propagated from the uncertainties in the tritium activity and the pool leakage, and is estimated to be 62%.
North Curtain Drain o North Curtain Drain tritium activity: Activity is above the minimum detectable activity and the sample is a monthly composite of water from the NCD. Estimated uncertainty for the activity concentration is 30%.
o North Curtain Drain Volume: Estimated uncertainty is 20%.
o North Curtain Drain Activity Collected: The uncertainty in the activity release rate (uCi/month) is propagated from the uncertainties in the tritium activity and the volume collected and is estimated to be 36%.
Sphere Foundation Drain Sump o Sphere Foundation Drain Sump tritium activity: Activity is below or slightly above the minimum detectable activity and the sample is a monthly composite of water from the SFDS. Estimated uncertainty for the activity concentration is 40%.
o Sphere Foundation Drain Sump Volume: Estimated uncertainty is 20%.
o Sphere Foundation Drain Sump Activity Collected: The uncertainty in the activity release rate (uCi/month) is propagated from the uncertainties in the tritium activity and the volume collected and is estimated to be 45%.
Activity Collected from NCD and SFDS The uncertainties in the NCD activity collected (36%) and the SFDS activity collected (45%), are estimated to produce an uncertainty of 57% in the total activity collected in the drain systems.
Results The amount of tritium released (West Pool) was compared to the amount of tritium collected (NCD + SFDS). The NCD and the SFDS systems are expected to collect the vast majority of the water from the U I SFP, based on the depression in the groundwater created by the SFDS. Continuing hydrogeological studies in 2006 support this assumption. This comparison was performed on the monthly data and the annual aggregate data. For 10 out of 12 months in 2006, there was more H-3 activity collected by the drain systems than was released from the West Fuel Pool. On an average annual basis, the West Fuel Pool releases accounted for about 30% of the amount collected by the drain systems.
Figure 1 and Table I show the results in a graphical and tabular format, respectively.
Figure 1 indicates that the error bars overlap in most months; however, on an average basis, the amount collected in the drain systems is higher than the amount calculated to be released from the Unit 1 West Pool. Figure 1A shows the same data as Figure 1, but without the month of January, which accounted for almost half of the activity collected in the drain systems over the year.
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Tritium Mass Balance for Unit I Spent Fuel Pool - 2006 Draft Evaluation of Results Based on the results of the tritium balance for 2006, there is not a matching balance of activity released from the UI SFP and the activity collected in the NCD and SFDS Systems. About 30% of the total activity collected in the drain systems is accounted for by the activity calculated to be released from the Unit I West Pool. However, based on the uncertainties in the calculation, this percentage could range from about 7% to over 100%. Of course, a value near 100% would indicate that the West Pool leakage is fully accounted for by the drain system tritium. While not definitive, the data does suggest that there is more tritium being collected in the drain systems than is being released from Unit 1 West Pool.
The reasons for this imbalance could be one or more of the following:
- 1. There is an additional source of tritium adding to the amount being discharged from the Unit 1 West Pool. Based on data from the dye tracer testing that became available in early 2007, there is evidence of communication of between Unit 2 spent fuel pool area and Unit 1. It is possible that contaminated soils from previous spills in the Unit 2 area, including Unit 2 spent fuel pool leakage is contributing to the activity in the North Curtain Drain and Sphere Foundation Drain Sump.
- 2. The actual leakage from the Unit 1 pool may be larger than the currently calculated value of 65 gallons per day.
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Tritium Mass Balance for Unit 1 Spent Fuel Pool - 2006 Draft Unit 1 H-3 Balance Results 80.0 70.0 60.0
.*50.0 0
Mot E 40.0-E 30.0-20.0 10.0 0.0 Month A]...*.... mCi NCD + SFDS Collected......
-7mCi West Pool released]
Figure 1 - Unit 1 Tritium Balance Results - 2006 Page 4
Tritium Mass Balance for Unit 1 Spent Fuel Pool - 2006 Draft Unit I H-3 Balance Results 14.0-77r 12.0-10.0 8.0 E
E 4.0 2.0 0.0 4.
=E 0
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0 0
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Month A... mCi NCD + SFDS Collected mCi West Pool released Figure IA-Unit 1 Tritium Balance Results - 2006 (January Omitted)
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Tritium Mass Balance for Unit I Spent Fuel Pool - 2006 Draft Table 1 - Unit 1 Tritium Balance Results Table - 2006 NCD H3 mCi Collected SFDS H3 mCI Collected Total Urain Systems H3 mCi Collected Total Drain Systems H3 mCi - Range West Pool H3 mCi Released west Pool H3 mCI Released -
Range Percent accounted for by 65 gpd Month Jan-06 11.9 34.2 46.1 20-73 2.0 0.7-3 4%
Feb-06 3.8 3.9 7.7 3-12 3.7 2-7 49%
Mar-06 0.8 5.0 5.8 3 - 9 2.3 0.9 - 4 39%
Apr-06 3.3 4.3 7.6 3-12 4.6 2-8 61%
May-06 3.6 3.4 6.9 3 - 11 2.0 0.8 - 3 29%
Jun-06 7.5 0.0 7.5 3 - 12 2.0 0.8 - 3 26%
Jul-06 3.3 1.1 4.4 2-7 2.3 0.9-4 53%
Aug-06 2.1 0.0 2.1 1-3 2.4 0.9-4 113%
Sep-06 2.4 0.0 2.4 1 - 3 2.1 0.8 - 4 90%
Oct-06 2.8 0.0 2.8 1 - 4 2.1 0.8-3 74%
Nov-06 4.6 0.0 4.6 2 - 7 2.0 0.8 - 3 45%
Dec-06 1.1 0.0 1.1 0.5-2 2.1 0.8-3 186%
Total 47.1 51.9 99.1 42-156 29.7 9 -40 30%
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