ML052690310
| ML052690310 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 09/15/2005 |
| From: | Connecticut Yankee Atomic Power Co |
| To: | NRC/FSME |
| sam10 | |
| Shared Package | |
| ML052690098 | List: |
| References | |
| Download: ML052690310 (35) | |
Text
Groundwater Monitoring and Relevance to LTP Compliance Meeting with USNRC September 15, 2005 1
Discussion Topics c LTP Compliance Criteria c Soil Characterization Results
- Tank Farm Bedrock Contamination Status
- Groundwater Monitoring Results c Groundwater Modeling Results O Going Forward Monitoring Plan
- Groundwater Recharge and Recovery from Dewatering c Actions Prior to Start of 18 Month Groundwater /
Monitoring Period 2
LTP Compliance Criteria Dose Modeling and Final Status Surveys Of
- Land Areas
- Three dose pathways included
>> Soil
>> Existing Groundwater
- Areas impacted by aquifer plume
>> Future Groundwater
- From concrete using the "Basement Fill Model" Al 25mr / yr > DTotal =DSoil Existing GW +
FutureGW 3
LTP Compliance Criteria Site Release Criteria ONRC 25 mrem/yr TEDE from all pathways plus ALARA
> Administrative targets o 8 mrem/yr allotted to soil (Industrial Area)
- 2 mrem/yr allotted to future groundwater (Basement Fill Model)
- 9 mrem/yr existing groundwater
- Total of 19 mrem/yr corresponding to State of Connecticut criteria v State of Connecticut 19 mrem/yr TEDE from all pathways plus ALARA Additional criteria to meet EPA Maximum Contaminant Levels (MCLs) demonstrated by monitoring well sampling v Soil/Bedrock Remediation Target Remediate media that could affect the ability to meet MCL concentrations in groundwater at time of property transfer 4
LTP Compliance Criteria Determination of Existing Groundwater Dose o Requirements at time of notification of the NRC of the intent to release an area from the license:
- Use highest concentration measured at any point, in the survey area or within the capture zone radius (100 meters) of any point in the survey area
- Monitoring well to be used in the dose calculation will have been sampled quarterly for at least 18 months including two spring high water periods
- Sample results trend has shown groundwater concentrations in the highest concentration monitoring well to be steady or decreasing
- Existing groundwater dose calculated by dividing groundwater concentration(s) by groundwater DCGLs and comparing the result to the GW target dose 5
LTP Compliance Criteria Start of 18 Month Groundwater Monitoring Period oC Fate and Transport simulations have determined the projected area of highest groundwater concentration K Existing and new groundwater wells are in place to adequately monitor the area(s) of anticipated highest groundwater concentrations o In areas where remediation has been conducted below the average water table using groundwater suppression:
- Remediation has been completed
- Excavation has been backfilled
- Groundwater depression has been ended
- Groundwater elevation returned to normal levels 6
Rad Remediation Below Groundwater Table RCA Sttus as of 9/1406 PRIMARY WATER BOUNDARY
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Soil Characterization Results Summary of Soil Sample Results
,0 Extensive subsurface soil sampling program conducted since 1997
- All suspect areas sampled to bedrock or 24+ feet below grade o Few low potential areas remain to be sampled and results evaluated
- Only remediation below normal water table remaining is bedrock in Tank Farm area
- Bedrock remediation in Tank Farm area to be completed by end of September
,AOS 8
Tank Farm Bedrock Contamination Status
- Radiological contamination observed in bedrock fractures in area of former tank farm and ion exchange building.
e Contaminated fractures were characterized using down-hole gamma spectroscopy and off-site laboratory analyses.
c Deepest contamination observed at 1.5 feet below top of rock (about -2 ft MSL). A 9
Tank Farm Bedrock Contamination Status c Contamination exceeding groundwater protection screening concentration has been bounded by additional sampling and analysis.
e~ Fractured bedrock exceeding screening concentration will be removed.
10
1_z_ T-0 Rock Boing. -Cotmiae Below screening concentrationAhi 3
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Groundwater Monitoring Results e Plant-related nuclides detected in June 05 sampling event:
- Sr-90,
- Tritium e Historic nuclide detections have included Cs-137, Co-60 12
0 125 250 CH2MHILL PA=
Feet 13 t/ovrieo/meds3NCT-Yankee/MXD/GWQ~05/Sr-90-UNCONFINED_06_05.rmxd JAely 9/1/2005 FIGURE 6-17 INFERRED DISTRIBUTION OF STRONTIUM-90 (pCVL) IN THE UNCONFINED AQUIFER AT THE INDUSTRIAL AREA AND UPPER PENINSULA AREA OF THE HADDAM NECK PLANT JUNE 2005 HADDAM NECK, CT
FIGURE 6-18 N
INFERRED DISTRIBUTION OF STRONTIUM-90 (pCiL) IN THE CONFINED AQUIFER 0
250 500 AT THE INDUSTRIAL AREA AND UPPER PENINSULA AREA OF THE HADDAM NECK PLANT JUNE 2005 1 4 CH2MHILL.L.1 Feet HADDAM NECK, CT 14
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N FIGURE 6-15 INFERRED DISTRIBUTION OF TRITIUM (pCiL) IN THE UNCONFINED AQUIFER 0
100 200 AT THE INDUSTRIAL AREA AND UPPER PENINSULA AREA OF THE HADDAM NECK PLANT JUNE 2005 Feet HADDAM NECK CT 15 boornr erojects3\\CTYankee\\MXD\\GW0Q2_S\\TrefiumUNCONFINED_0 05.noxd B0odinso9
N FIGURE 6-16 INFERRED DISTRIBUTION OF TRITIUM (pCiOL) IN THE CONFINED AQUIFER LLA 0 100 200 AT THE INDUSTRIAL AREA AND UPPER PENINSULA AREA OF THE HADDAM NECK PLANT JUNE 2005 16MHIooLL FeejectstTAYanke\\MXD\\GW (2 05\\Tdium 3 F.Ft HADDALm NECK CT 16
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Groundwater Modeling Results c Model Domain Map c Model Domain Bedrock Surface Map 0 Particle Track from Operational Period e Particle Track from Post-Closure Period 17
CY Regional Groundwater Model Geologic Data Points rN W-E
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USGS WatrRe so reports Survey of Private Wells by Connecticut Yankee staff S TRKAT E X Wells and borings drilled on Connecticut Yankee property 1hhh Red line indicates outer boundary of active area of groundwater model Figure 1 (1Cf7
L - -
CY Regional Groundwater Model Top of Rock Elevation Data sources:
Well and boring data Surficial Geology Maps (subtract thickness from ground topo)
Soils Maps (subtract thickness from ground topo)
Red line indicates outer boundary of active area of groundwater iTRATE X model Figure 2 19
Groundwater Modeling Results Description of Layers Groundwater Model Layer Descriptions Layer Number Stratigraphy Thickness 1
Soil (unconsolidated) 1/3 of soil thickness 2
Soil (unconsolidated) 1/3 of soil thickness 3
Soil (unconsolidated) 1/3 of soil thickness 4
Bedrock 25 ft 5
Bedrock 25 ft 6
Bedrock 37.5 ft 7
Bedrock 37.5 ft 8
Bedrock 75 ft 9
Bedrock 400 ft 20
Leged E
Constant Head a
Drain a
General Head Boundary
/
Barrier Wall Reverse Particle Tracking from Major Monitoring Wells In Steady-state Operational Mode S T R ATE X Particles started at 0.1 and 0.9 times depth of layer In which 11I1111 each monitoring well Is located irel-"i
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8124/06 Figure 35 21 Co0
CY Groundwater Model
&N o c
Particle Track Leged Layer of Travel 0
100 200 300 400 U
U Legend Constant Head Gene Head Boundary N
Drain Barrir Wall Forward Particle Tracking from two rows of arbitrary points STRATEX Forward Particle-Tracking from two row* of arbitrary points during post demo conditions under average annual recharge Particles started at 0.1 and 0.9 times depth of layer.
Particles were started In model layers 3 and 4 01F2grn4
.1E111. 11 Flgure 45 22 CIo
Going Forward Monitoring Plan Monitoring Well Network for License Termination o Well network is derived from compilation of site observations, long-term water level monitoring, well testing, and use of flow simulations.
c Previous wells that were destroyed during demolition will be replaced and new wells installed at selected locations to monitor contaminant status.
H 23
24
Going Forward Monitoring Plan Groundwater Monitoring Schedule for License Termination MonIt Date Season Sample Event 0
Sep-05 Fall-05 I
Oct-05 2
Nov-05 3
Dec-05 Winter-05 4
Jan-06 5
Feb-06 6
Mar-06 7
Apr-06 Spring Spring-06 8
May-06 9
Jun-06 Sumnmer-06 10 Jul-06 II Aug-06 12 Sep-06 Fall-06 13 Oct-06 14 Nov-06 15 Dec-06 Winter-06 16 Jan-07 17 Feb-07 18 Mar-07 19 Apr-07 Spring Spring-07 20 May-07 21 Jun-07 Summer-07 22 Jul-07 23 Aug-07 25
Going Forward Monitoring Plan Monitoring Well Installation and Initial Sampling Schedule 0 Start 18-month monitoring period with Fall 2005 sampling event.
e Sampling event to start Sept 05, complete Oct 05.
0 Well installation underway.
c Sampling of new wells scheduled no less than 5 days after development.
as.TO) 26
Groundwater Recharge and Recovery from Dewatering 0 Groundwater elevations in, and out of, the dewatered areas are being measured regularly.
9 Inspection of plotted groundwater elevation contours indicates that groundwater elevation has recovered to seasonal norm as of 1 1 Sept 05.
27
Groundwater Recharge and Recovery from Dewatering 5
4 3
2
.2 CD 1
0
-1
-2
-3
-4
-5 4=-
1-Aug-05 6-Aug-05 11-Aug-05 16-Aug-05 21-Aug-05 26-Aug-05 31-Aug-05 5-Sep-05 10-Sep-05 Date 15-Sep-05 l-4-
- MW-130 vbt Surrp -v-
- WI-131 S 28 C-Z
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-. WdEL-...dw 2 Q ft MSL M
L1/2Lm Inkred "W Eiet on CFtor N
Inrtad TOg GW Elembon MortonnweO in Un.#pneted Am*
OYACE
- Haddan Neck Plant
('roundwatrt eovation Obervwation and Inferred Contours
¢ Mu
-Orlgd hj soered her 1 Sep 2005 30
31 1
MortornWel In Devlema Ae 1 1 Sep 2005 31
32 crlu
Actions Prior to Start of the 18 Month Groundwater Monitoring Period 33
Completed Actions Related to 18 Month Monitoring Period
<> Phase 2 Hydrogeologic Work Plan scope supporting the on site groundwater monitoring is complete c Capture Zone Study is complete c New monitoring well locations identified Y New monitoring wells are being installed c The PAB, RHR area has recharged o Groundwater Suppression secured including the Containment Mat sump A 34
Additional Actions Prior to start of 18 Month Monitoring Period
- Complete the remediation of the bedrock under the Tank Farm
- Complete the rad assessment of the areas affected by the remediation of bedrock
- Backfill Tank Farm area (Southeast PAB Excavation) c Complete monitoring well installation 9 5 day waiting period before sampling following monitoring well development
- Conduct the September groundwater sampling event 35