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1 Overview of the EPRI Groundwater Assessment Program Presented at: RETS-REMP Workshop, June 26-28, 2006 Mashantucket, CT Eric L. Darois, M.S., CHP Dave.

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Presentation on theme: "1 Overview of the EPRI Groundwater Assessment Program Presented at: RETS-REMP Workshop, June 26-28, 2006 Mashantucket, CT Eric L. Darois, M.S., CHP Dave."— Presentation transcript:

1 1 Overview of the EPRI Groundwater Assessment Program Presented at: RETS-REMP Workshop, June 26-28, 2006 Mashantucket, CT Eric L. Darois, M.S., CHP Dave Scott, M.S., CPG, LEP EPRI Consultants (RSCS, Inc.) Sean Bushart EPRI Ron Cardarelli, M.S. CN Associates, Inc.

2 2 Program Objectives and Scope Phase 1: –Perform a site-specific assessment of Groundwater Contamination Risks. –Bring Lessons-Learned to each site from Prior Groundwater Investigations. –2 to 4 Days, 2 Professionals Health Physics/REMP Geologist/Hydrogeologist –Prepare site-specific report with recommendations based on assessment Phase 2: – Develop Industry Guideline on Groundwater Protection Phase 3: –Advanced Nuclear Project – Groundwater Protection Lessons Learned in development of new nuclear plants

3 3 RETS/REMP 2005 Discussion Ground Water Monitoring Guidance for Nuclear Power Plants (EPRI Report No ) –150-page EPRI Report Two Decommissioning Sites One Operating Site –Historical Review –Requirements –Potential Source Locations –Investigation Methods and Tools –Determining Occurrence, Nature, Extent –Sampling Considerations –Data Analysis and Interpretations Recommended GW Monitoring as Part of REMP

4 4 Assessments/Experience Performed and Gained Yankee Rowe (Decommissioning) Connecticut Yankee (Decommissioning) TMI EPRI Assessment Braidwood Assistance Indian Point Assistance

5 5 Observations & Recommendations Define Program Objectives –Radionuclides, MDCs, and Positive Results –Sampling Regime –Sampling Methods –Data Assessments –Sampling Methods and Field Parameters Consider Preventative Maintenance Programs for Wells Consider Soil Sampling for H-3 Sources

6 6 Observations & Recommendations (Cont) Investigation Complexity Results in Wide Variation in Duration –Sand-Laden Aquifer –Fractured Bedrock –Deep Bedrock –Barriers to GW Flow

7 7 Observations & Recommendations (Cont) Tritium Saturated Concrete Documentation of Spills and Leaks –Soil Contamination Events –Secondary Water –Tank Leaks –SFP Minor Leaks Resource Needs not Recognized Data Management

8 8 Observations & Recommendations (Cont) Data Management –Electronic Data vs Paper –What Radionuclides? –MDAs ? Required vs Achieved –Sample Event Planning –Sample Control –Data Control –Data Assessment Statistical Analysis Trend Analysis

9 9 Recognize the Iterative Process of GW Investigation Proceed with a phased approach that implements a scientific method Develop a Conceptual Site Model (CSM) Evaluate the existing site data (hydrogeology, source areas, contaminant distribution, transport mechanisms) Formulate a preliminary CSM (hypothesis) that explains the observed data Collect data: drill monitoring wells, sample and analyze GW, and conduct hydrogeologic testing Evaluate and interpret the resulting data Evaluate Results Develop/Revise CSM Define Data Gaps Collect Data

10 10 Designing a GW Investigation Evaluate possible sources of contaminants Evaluate possible radionuclides Determine GW flow directions & mechanisms –Install monitoring wells Drilling methods –Overburden wells –Bedrock wells –Screen Depths –Measure GW levels –Sample and analyze GW determine concentrations Determine distribution

11 11 Tools for the Investigation Water-level monitoring –Precipitation (primary input to GW) –Surface water (tidal interaction with GW) –Ground water (flow direction and gradient) Water-level measurement techniques –Electronic measuring tapes Synoptic measurements in a set of wells –Data-logging pressure transducers Continuous measurements in selected wells

12 12 Example of GW Level Data Logging

13 13 More tools… Bedrock Borehole Logging Tracer studies Isotopic GW dating Packer Testing

14 14 Ground Water Sampling –Flow-through measurement cell to determine when samples are representative Temperature pH Turbidity Dissolved oxygen Specific conductance –Water-level meter –Bailed Samples –Low Flow Sampling Methods

15 15 Observations/Guidance Potential Primary GW Sources (10 to 50 Million pCi/L): –Spent Fuel Pools –Refueling Water Storage Tanks –Sumps Secondary Sources –Secondary Water Spills and Leaks Possible Large Volume Primary Radionuclides of Concern Sr-90, Co-60, Cs-137, and H-3. –Tritium is the most mobile and pervasive.

16 16 Conclusions State Regulations May Require Additional Considerations Engage Stakeholders Through All Phases GW investigations are Iterative –Maybe Years To Complete Need a Conceptual Site Model Additional Interest in EPRI Assessments Will Help to Implement NEI Initiative


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