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

Example of GW Level Data Logging

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