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Potential Sources of Groundwater Contamination at Nuclear Power Plants . RETS-REMP Workshop Nine Mile Point- Constellation Energy June 28-30 th , 2004 Eric Darois, CHP Robert Litman, Ph.D. Radiation Safety & Control Services, Inc. Stratham, NH. Experiences. Decommissioning Sites

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potential sources of groundwater contamination at nuclear power plants

Potential Sources of Groundwater Contamination at Nuclear Power Plants

RETS-REMP Workshop

Nine Mile Point- Constellation Energy

June 28-30th, 2004

Eric Darois, CHP

Robert Litman, Ph.D.

Radiation Safety & Control Services, Inc.

Stratham, NH

experiences
Experiences
  • Decommissioning Sites
    • Connecticut Yankee
    • Yankee Rowe
  • Groundwater Dose Contribution to License Termination (LT) Criteria
  • NRC LT Criteria (10CFR20 Sub E, 10CFR50.82)
    • 25 mrem/year + ALARA
      • All Pathways
      • Resident Farmer Typically Used
    • GW Contamination Requires Site Specific Dose Modeling (NUREGS)
hydrogeological terms
Hydrogeological Terms
  • Packer Testing
  • Hydraulic Conductivity
  • Pieziometric Surface
  • Slug Test
  • Pump Test
  • Mud and Wash Drilling
  • Rotosonic Drilling
  • Glaciolacustrine
  • Transmissivity
  • Overburden
cy operating history
CY Operating History
  • 582-Mwe Pressurized Water Reactor
  • Construction Period 1963 - 1967
  • Commercial Operation Jan 1, 1968
  • Permanently Shut Down December 4, 1996
cy decommissioning update
CY Decommissioning Update
  • Shutdown 12/96
  • Large Components Removed Complete
  • Final Survey of 400 Wooded Acres Complete
  • 1st GTCC Canister Located on ISFSI 4/04
  • Start Secondary Side Building Removal 5/04
  • Start Tank Farm Soil Removal 5/04
  • Start RCA Building Removals 7/04
  • Complete Fuel Transfer 4/05
  • Complete Physical Decommissioning 12/06
  • Release Non-ISFSI Areas From License Mid-2007
cy groundwater investigation history
CY Groundwater Investigation History
  • Evidence of GW Contamination During Operation
    • Potable Wells
    • CTMT Mat Sump – H-3 (~24,000,000 pCi/L)
    • Confirmed RWST Leak
    • Possible SFP Leak – Not Confirmed
  • 1997/1998 – 1st Monitoring Wells Installed
    • Initial Sampling H-3 and Gamma Only
    • 143,000 pCi/L H-3
  • Formal Hydrogeological Investigation Plan
    • CT DEP
    • 2 Phases – Includes Quarterly Sampling
    • Sr-90 Identified
  • GW Dose Model Developed for LTP
  • 2004 – Commitment to DEP
    • All Contaminants < EPA’s MCLs
      • 20,000 pCi/L H-3
      • 8 pCi/L Sr-90
bias detection
Bias Detection

Case 1: No Bias, Mn-54

March 2002 Data Set

bias detection13
Bias Detection

Case 2: + Bias, Tc-99

March 2002 Data Set

bias detection14
Bias Detection

Case 3: - Bias, Pu-241

March 2002 Data Set

soil remediation plans
Soil Remediation Plans
  • Remove Soil from Areas Containing Elevated Contamination to Bedrock – Target Area is Groundwater Source:
    • Tank Farm Area including Structures
    • East of Resin Storage Facility
    • Area between Containment and PAB
  • Install Well in Area to Monitor for any Residual Contamination
groundwater characterization activities
Groundwater Characterization Activities
  • Conduct Routine Groundwater Monitoring
  • Review and Document Existing Information - Phase II Plan, Task 1
  • Characterize Site-specific Hydrogeologic Conditions – Phase II Plan, Task 2
  • Develop Contaminant Fate and Transport Model – Phase II Plan, Task 3
ongoing groundwater monitoring
Ongoing Groundwater Monitoring
  • Continue Quarterly Groundwater Sampling
  • Decommission Un-needed Wells
  • Installed Water Level Monitoring System
    • 33 Monitoring Points, Including Shallow and Deep Zones
    • Include Surface Water Points at Storm Water Pond, River, and Canal
phase ii hydrogeologic work plan task 1
Phase II Hydrogeologic Work Plan: Task 1
  • Conceptual Site Model Elements
  • Review of Existing Hydrographs/Water Level Data
  • Assessment of Apparent Contaminant Source Areas
  • Catalog of Well and Boring Logs
  • Description and Mapping of Bedrock Features
  • Hydrogeologic Cross Sections
  • Preliminary Groundwater Geochemistry Evaluation
  • Evaluation of Substances of Concern
  • Preliminary Hydrogeology Evaluation
  • Measurement Data QC Review
  • Inventory of Nearby Water Supply Wells
phase ii hydrogeologic work plan task 2
Phase II Hydrogeologic Work Plan: Task 2
  • Implement Improved Bedrock Packer Tests
  • Install Bedrock Monitoring System Based On Packer Test Results
  • Assess Aquifer Hydraulic Conductivity
    • Packer Test Measurements
    • Mat Sump Observations - Long-term Groundwater Extraction
    • Slug Test Measurements - Localized Measurements
  • Assess Tidal Influence on Groundwater
  • Install Additional Monitoring Wells as Needed
  • Collect Other Supplemental Site-Specific Information to Support Fate and Transport Modeling
3 d fate and transport model task 3
3-D Fate and Transport Model: Task 3
  • Select Appropriate Simulation Code based on Site Conditions
  • Preliminary Conceptual Model Elements Include the Following:
    • Aquifer System Includes Shallow Unconsolidated Formation Overlying Fractured Bedrock
      • Large variability in unconsolidated system thickness
      • Bedrock appears to be anisotropic fractured system
    • Connecticut River is Ultimate Discharge Boundary
      • Paired wells near the river shore exhibit upward vertical hydraulic gradient
      • Consistent with the regional concept of the river as a discharge boundary.
cy lessons learned
CY Lessons Learned
  • Radionuclides DO NOT Travel Together in Aquifers
  • Site may have Separate Aquifers
  • Contamination can Migrate to Depths >150 feet.
  • Long Term Trends Are Important
    • Bias Detection
    • Seasonal Fluctuations
    • Rain Events
  • Consider Level Monitoring
    • Correlate to RainFall
  • Develop Conceptual Hydrogeologic Site Model
    • Well Placement
    • Bedrock Geophysics
    • Overburden Characteristics
yr operational history
YR Operational History
  • PWR, Operated from 1960 to 1992
  • Initially 485 Mwt, Uprated to 600 Mwt in 1963
  • Fuel Clad for ~14 years was Stainless Steel
  • During the time period 1960-1980 the SFP did not have an interior stainless liner
  • Significant IX Pit Leak - 1962
  • Built adjacent to Sherman Reservoir in the northern Berkshires using a Vapor Containment Design (the BRT)
  • Ceased Power Operation - 1992
yankee rowe potential groundwater contaminating events
Yankee Rowe Potential Groundwater Contaminating Events
  • Unlined SFP
  • IX Pit Leak 1962
  • Outside Storage Of Contaminated Materials
    • Refueling Equipment
    • Waste
  • Redistribution of Soil Contamination
    • RCA Snow Removal
    • Rain – Storm Drains
    • Wind
  • RX Head Impact – Outside Soil Contamination
  • Underground PVC Drain Pipe Leak
slide30

YNPS 1999 Concentration of H-3 in Ground Water

Sherman Spring

CB-6

CB-2

Grid N

CW-7

N

(True)

CW-8

CW-6

44.5 Deg.

CW-10

MW-6

CB-1

CB-9

CW-5

CW-9

MW-5

Monitoring Wells

(x are grouted)

Site Structures

Fence line

B-1

CW-1

MW-3

MW-2

CB-10

CW-11

CB-11A

CW-3

MW-1

CW-2

CB-12

CB-7

300-3000 pCi/L

B-3

CB-8

CW-4

3000-6000 pCi/L

CB-3

6000-10000 pCi/L

>10,000 pCi/L

Approximate Scale

0

200 ft

Well H-3

No. pCi/L

CB-1 4210

CB-2 1280

CB-3 <MDC

CB-6 666

CB-7 <MDC

CB-8 <MDC

CB-9 4010

CB-10 2330

CB-11A 2030

CB-12 <MDC

CW-2 <MDC

CW-3 <MDC

CW-4 <MDC

CW-5 <MDC

CW-6 <MDC

CW-7 <MDC

CW-8 360

CW-10 <MDC

CW-11 11600

MW-1 1290

MW-2 11470

MW-5 5610

MW-6 <MDC

B-1 2830

Sherman Spring <MDC

slide31

Sherman Spring,

YNPS Fall 2001 Concentration of H-3 in Ground Water

Grid N

N

(True)

44.5 Deg.

CB-6

0

200 ft

CB-2

Approximate Scale

CW-7

CW-6

CW-8

CW-10

MW-6

CB-1

CB-9

CW-5

CW-9

MW-5

B-1

CW-1

MW-3

MW-2

CB-10

CW-11

CB-11A

CW-3

MW-1

CW-2

CB-12

CB-7

CB-8

B-3

CW-4

CB-3

efforts beginning in 2003
Efforts Beginning in 2003
  • Complete groundwater monitoring program established that included:
    • Suites of radionuclides to be analyzed and relevant locations based on HSA
    • New locations for wells based on the site geology
      • Intermediate Depths 60 -200 feet)
      • Bedrock (some as deep as 300 feet)
      • Multiple wells at same location for three depths
    • Frequency for measurements which would adequately monitor changes in the GW
additional investigations
Additional Investigations
  • More Wells to Further Bound Plume
  • Step Draw Down Test to Understand Aquifer Connections
  • Install Network of Level Transducers
yankee rowe lessons learned
Yankee Rowe Lessons Learned
  • EPA MCLs Selected for Criteria
  • Prior Investigations Not Rigorous
    • Little Regulatory Involvement
  • Involve All Stakeholders
  • Analyze for Wide Suite of Radionuclides
  • Include Non-Rad Constituents
  • Long Term Trends Important
major lessons learned
Major Lessons Learned

Don’t Wait

MCL’s Count