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EPRI Guideline for Implementing a Groundwater Protection Program at Nuclear Power Plants

EPRI Guideline for Implementing a Groundwater Protection Program at Nuclear Power Plants . RETS REMP 2007 Philadelphia, PA June 25 – 27, 2007 Eric L. Darois, CHP. Implementing Schedule. Draft Issued March 2007 for Industry Comments Review and Disposition Comments – June 2007

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EPRI Guideline for Implementing a Groundwater Protection Program at Nuclear Power Plants

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  1. EPRI Guideline for Implementing a Groundwater Protection Program at Nuclear Power Plants RETS REMP 2007 Philadelphia, PAJune 25 – 27, 2007 Eric L. Darois, CHP

  2. Implementing Schedule • Draft Issued March 2007 for Industry Comments • Review and Disposition Comments – June 2007 • Issue Final Document – November 2007

  3. EPRI Groundwater Protection Guidelines Objectives Provide guidance for development of robust and technically sound optimized programs for groundwater protection at nuclear power plants. Control Licensed Material from Entering the Subsurface Minimize Unplanned Unmonitored Releases Minimize Long-Term Costs for Remediation

  4. Ameren UE American Electric Power American Nuclear Insurers AREVA Connecticut Yankee Constellation Energy Group Dominion DTE Energy Co. Duke Energy Corp. Energy Northwest Entergy Exelon FirstEnergy Nuclear Operating Co. Florida Power & Light Co. General Electric Nuclear Energy Institute Nuclear Management Co. Ontario Power Generation Omaha Public Power District Pacific Gas & Electric Co. Public Service Electric & Gas Co. PPL Susquehanna Progress Energy Southern Nuclear Operating Co. Southern California Edison South Texas Project Nuclear Operating Co. Tennessee Valley Authority Westinghouse Yankee Atomic Electric Company Participating Companies

  5. Guideline Content • Evaluation of Potential Subsurface Releases • Establishing The Priority Index Values • Determining The Program Levels With The Graded Approach • Establishing a Site Conceptual Model • Locating, Installing and Testing Groundwater Monitoring Wells • Establishing a Groundwater Sampling and Analysis Process • Evaluating Sampling and Monitoring Data • Program Validation and Review • Communicating With Stakeholders and Regulators • Potential Mitigating Actions • Decommissioning Considerations

  6. Appendices • Appendix A: Practical Examples Of A Graded Approach Application • Appendix B: List Of Guidance Statements • Appendix C: Non-technical Issues That May Be Considered When Determining Priority Indices • Appendix D: Sample List Of Systems, Structures And Components • Appendix E: Checklist Of Elements To Include In A Review Of Systems, Structures, Components And Work Practices • Appendix F: Determination Of Condition Of SSCs • Appendix G: Basis For ‘Hazard’ And ‘Mobility’ Priority Factor Values • Appendix H: Site Characterization And The Site Conceptual Model • Appendix I: Identifying Predominant Groundwater Flow Directions And Mechanisms • Appendix J: An Example Of A Groundwater Monitoring Procedure • Appendix K: An Example Of A Groundwater Sampling Plan • Appendix L: An Example Of A Study Conducted To Estimate The Effect Of Atmospheric Deposition Of Tritium On Groundwater • Appendix M: Fate And Transport Numerical Modeling

  7. Evaluation of Potential Subsurface Releases • Historical Spills • Evaluate SSCs Containing Liquid Radioactivity • Identify Preventive Maintenance and Inspection Programs • Evaluate Work Practices • Evaluate Potential Ongoing Releases

  8. Establishing Priority Index (PI) Values • Performed for: • Selected SSCs and Work Practices • Major Changes in SSCs/Work Practices • Maximum PI Score among All SSCs/Work Practices Determines Site Score • Mitigating Actions Are Allowed to Lower Score • PI Factors • Likelihood – 4 Factors • Consequence – 4 Factors

  9. Determination of Contamination RiskPriority Index Methodology Priority Index (PI)= Likelihood x Consequence x N HL = History (0-3) CL = Condition (0-3) DL = Design (0-3) PL = Pre-release Detection (1-3) IC = Inventory (1-3) HC = Hazard (1-3) MC = Mobility (1-3) PC = Post-release Detection (1-3) N – Normalizing Factor. Resulting Scores 1 to 100

  10. EPRI Groundwater Protection Guidelines:Step 1-Priority Index Determination

  11. Priority Index = 76Likelihood Priority Factors • For Site 1, The Containment Sump Re-Circ Line has a calculated PI of 76. • Likelihood Priority Factors: • History (3): • A containment sump re-circulation line has been identified as having leaked to the subsurface • Condition (2): • A pressure test of the system has did not reveal a substantial volumetric leak. However, some uncertainty over the possibility of a small leak (< 1 gpd) remains. • Design (3): • This is a single-walled subsurface pipe. • Pre-Release Detection (3): • A non-catastrophic release would not be detected until radioactive material had been detected external to the pipe.

  12. Priority Index = 76Likelihood Calculation

  13. Priority Index = 76Consequence Priority Factors • For Site 1, The Containment Sump Re-Circ Line has a the max calculated PI value. • Consequence Priority Factors: • Inventory (3): • Low volume of liquid but high concentration (~2E7 pCi/L) of tritium • Hazard (3): • This pipe likely contains Cs-137 and Sr-90 (from prior fuel defects). • Mobility (3): • Potential contamination from this source could enter a fractured bedrock system. • Post-Release Detection (2): • An onsite monitoring well is located approximately 300 feet from this pipe in the down-gradient flow path.

  14. Priority Index = 76Consequence Calculation

  15. Priority Index = 50Likelihood Priority Factors • For Site 3, the Aux Boiler Sump is unlined and may have leaked water to the environment. • Likelihood Priority Factors: • History (2): • The sump’s water inventory has been observed to vary, indicating that some of this water was lost to the environment. • Condition (2): • Various attempts in sealing the sump have not corrected the above condition. • Design (2): • The sump was sealed with a coating (which may not be functioning properly) during its original construction. • Pre-Release Detection (3): • Leakage through this sump is not detected until its entry into the environment

  16. Priority Index = 50Likelihood Calculation

  17. Priority Index = 50Consequence Priority Factors • For Site 3, the Aux Boiler Sump is unlined and may have leaked water to the environment. • Consequence Priority Factors: • Inventory (1): • Low liquid volume with a moderate tritium concentration (180,000 pCi/L). • Hazard (1): • Only very low levels of activation products have been detected in this sump. • Mobility (3): • Tritium is very mobile in the environment. • Post-Release Detection (3): • This site currently has only two onsite monitoring wells, neither of which is located down-gradient from this sump – leak from this system may not be detected in these wells.

  18. Priority Index = 50Consequence Calculation

  19. EPRI Groundwater Protection GuidelinesStep 2- Graded Approach Determination

  20. Recommended Groundwater Protection Program (Level I “Baseline”) Design and Installation Requirements • Develop The Site Conceptual Model (5.1) • Review Aerial Photos And Engineering Drawings (5.2) • Review Previous Hydrogeologic Reports (5.3) • Evaluate Potential Receptors Of Groundwater Contamination (5.4) • Review State And Local Regulations (5.5) • Determine Groundwater Elevation (5.6.1) • Evaluate Pre-operational Groundwater And Geologic Data (5.6.2) • Determine Regional Hydrogeologic Characteristics (5.6.3) • Install Wells (5.7.1) • Determine Horizontal Distribution And Movement (5.7.2) • Establish And Document DQOs For Well Drilling (6.1) • Institute Configuration Management For Well Drilling (6.2.1) • Review Permitting Requirements For Well Drilling (6.2.2) • Ensure Sampling Accessibility (6.2.3) • Construct Monitoring Wells (6.3) • Develop And Implement A Maintenance Program For Monitoring Wells (6.4)

  21. Recommended Groundwater Protection Program (Level I “Baseline”) – Sampling, Analysis, and Data Management • Establish And Document DQOs For Groundwater Sampling (7.1) • Establish Sample Collection Procedures (7.2) • Establish Analyte List(s) (7.3) • Establish MDC Requirements And Criteria For Positive Detection (7.4) • Establish Sample Volume, Container And Preservation Requirements (7.5) • Establish Sampling Schedule (7.6) • Validate Analytical Results (7.7) • Evaluate Analytical Data (8.1) • Evaluate Field Water-quality Indicator Data (8.2) • Provide For Management And Data Quality Assessment Of Analytical Data (8.3)

  22. Recommended Groundwater Protection Program (Level I “Baseline”) – Data Assessment • Evaluate Background Radionuclide Concentrations (8.4.1) • Evaluate Atmospheric Deposition Of Plant-related Radionuclides (8.4.2) • Evaluate Plant-related Liquid Pathways (8.4.3) • Review And Revise The Site Conceptual Model (8.5) • Perform Initial Independent Review (9.1) • Revalidate Priority Index Ratings (9.2)

  23. Recommended Groundwater Protection Program (Level II & III) • Level II (50 < PI ≤ 75) • Implement All Program Elements From Program Level I • Determine Vertical Distribution And Movement (5.7.3) • Consider Use Of Water-level Transducers (6.5.1) • Level III (75 < PI) • Implement All Program Elements From Program Levels I And II • Aquifer Test For Flow Regimes, Connectivity, Hydraulic Conductivity (5.7.4) • Conduct Geophysical Testing (6.5.2) • Consider Use Of Hydraulic Conductivity Testing (6.5.3) • Consider Use Of Hydrophysical Testing (6.5.4) • Consider Use Of Fate And Transport Numerical Modeling (8.6)

  24. Establishing a Site Conceptual Model • Initial Data Input • Aerial Photos, Engineering Drawings, Construction Photos • Prior Hydrogeologic Reports • Regional Groundwater Flow Information • Ongoing Development of a CSM • Well Installations and Monitoring • Water Elevations • Groundwater Quality Data (Temp, pH, Conductivity, Concentrations, Oxygen etc..) • Flow Regimes, Connectivity and Conductivity • Horizontal/Vertical Distribution and Movement

  25. Well Installation • Data Quality Objectives Process – Document Process • Purpose • Depth and Well Design • Measurement of Field Water Quality Parameters During Drilling/Construction • Document Final “as-built” and Include in Configuration Management Process

  26. Sampling and Analysis and Assessment • DQO Process Required • Written Sample Collection Procedures • Justify Analyte List • Specify Required Minimum Detectable Concentrations • Specify Container Types and Sample Preservation Requirements • Establish Sampling Schedule and Rationale • Establish Procedure for Data Validation • Data Base Management

  27. Program Validation and Review • Periodic Independent Review • < 5 years • Revalidation of Priority Index

  28. Additional Sections • Communicating with Stakeholders • Potential Mitigating Actions • Decommissioning Considerations • References • Additional Technical References • Glossary

  29. Summary of EPRI Guidelines and their Implementation • Development of Risk Based Index based upon SSCs • “Graded Approach Strategy” allows for optimized approach to Groundwater Monitoring by utilities • Baseline Program is a commitment from the industry to perform preventative monitoring and control, and will require some plant resources to implement • EPRI supplemental support available (GW Assessments) for implementation

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