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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.
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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.
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
RETS/REMP 2005 Discussion • Ground Water Monitoring Guidance for Nuclear Power Plants (EPRI Report No. 1011730) • 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
Assessments/Experience Performed and Gained • Yankee Rowe (Decommissioning) • Connecticut Yankee (Decommissioning) • TMI EPRI Assessment • Braidwood Assistance • Indian Point Assistance
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
Observations & Recommendations (Con’t) • Investigation Complexity Results in Wide Variation in Duration • Sand-Laden Aquifer • Fractured Bedrock • Deep Bedrock • Barriers to GW Flow
Observations & Recommendations (Con’t) • Tritium Saturated Concrete • Documentation of Spills and Leaks • Soil Contamination Events • Secondary Water • Tank Leaks • SFP “Minor” Leaks • Resource Needs not Recognized • Data Management
Observations & Recommendations (Con’t) • 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
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
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
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
More tools… • Bedrock Borehole Logging • Tracer studies • Isotopic GW dating • Packer Testing
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
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.
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