ML22136A116
| ML22136A116 | |
| Person / Time | |
|---|---|
| Site: | Nuclear Energy Institute |
| Issue date: | 05/11/2022 |
| From: | Darois M Nuclear Energy Institute, Radiation Safety & Control Services |
| To: | Office of Nuclear Material Safety and Safeguards |
| Barr C | |
| Shared Package | |
| ML22117A070 | List: |
| References | |
| Download: ML22136A116 (16) | |
Text
Utilizing the Nuclear Energy Institute (NEI) 07-07 Industry Groundwater Protection Initiative as a Foundation for Addressing Subsurface Site Assessments USNRC 2nd Annual Public Workshop on Subsurface Investigations - Via MS Teams May 11th, 2022 Matt Darois, CGWP, Corp. Environmental
& Engineering Manager Radiation Safety & Control Services Inc.
medarois@radsafety.com
Outline
- Recap of graded approach to subsurface characterization (July 2021 Workshop)
- Triad and graded approach at nuclear sites
- Use of a Conceptual Site Model (CSM)
- NEIs 07-07 Groundwater Protection Initiative
- Scope (subsurface investigations/decommissioning)
- Hydrogeologic CSM within the 07-07 Framework 07 GWMP Objectives to address and plan subsurface site assessment
- Hydrogeology: aquifer(s), preferential flow paths, barriers to flow, fixed head boundaries, anthropogenic effects etc.,
- System, structure, component and work practice risk ranking
- Remediation and record keeping
- Oversight/updates
- Applied examples and discussion
Triad Approach https://triadcentral.clu-in.org/
- Systematic Planning:
- Land use Survey / Historical Site Assessment
- Develop a dynamic Conceptual Site Model (CSM)
- CSM drives characterization plan and methods Dynamic Work Strategies:
- DQOs
- The characterization plans tech basis is the CSM
- Characterization data driven decision making in the field
- Characterization and Remediation
- Characterization methods selected to meet DQOs with rapid deployment capabilities/tech
- Real-Time Measurements:
- Mobile labs, and instrumentation
- Remote sensing, GIS/GPS data integration with digital twins
What is a Hydrogeologic CSM?
A hydrogeologic CSM is a description of various natural and anthropogenic factors that govern and contribute to the movement of groundwater in the subsurface Kresic N., Mikszewski A., CRC Press 2013 Collection of tested hypotheses that iteratively attempt to answer:
Where is GW coming from?
What type of porous media is it flowing through?
How much GW is there and how fast is it flowing?
Where is GW going?
How did GW behave in the past and how will it change in the future (natural and anthropogenic)?
What are the past, present and future contamination risks to GW?
How do contaminants move in GW? (F&T)
Source:
https://www.sciencedirect.com/science/article/
abs/pii/S0022169418309387
07-07 Industry Groundwater Protection Initiative Initially developed in 2007 to describe the industrys Groundwater Protection Initiative Applicability: Operating and decommissioning nuclear power plants and new plants under construction after 2006 Voluntary program that all US commercial nuclear fleet Chief Nuclear Officers (CNOs) agreed to Subsequently USNRC added review of GW monitoring programs to routine REMP inspection procedures (71124.07 Radiological Environmental Monitoring Programs)
Initiative provides utilities improved management and response to inadvertent release of radioisotopes that may result in low but detectable plant-related materials in subsurface soils and water.
Three Parts:
- 1) GW Protection Program
- 2) Communication
- 3) Program Oversight https://www.nrc.gov/docs/ML1914/ML19142A071.pdf
Part 1:
Groundwater Protection Program Manage inadvertent Rad releases that enter GW:
- Objective 1: Site Hydrology and Geology:
Ensure site characterization provides an understanding of predominant GW gradients based on current site conditions. This characterization is the basis of the CSM
- Objective 2: Site Risk Assessment Evaluate all systems structures, components [and work practices] that could contain lic. material where there is a credible mechanism [for a release] to groundwater
- Objective 3: On-going Groundwater Monitoring Establish an on-site GW monitoring program to ensure timely detection of inadvertent radiological releases to GW
- Objective 4: Remediation Establish a remediation protocol to prevent migration of lic. material off-site and to minimize decommissioning impacts
- Objective 5: Record Keeping Records of leaks, spills and remediation efforts are retained to meet the requirements of 10 CFR 50.75(g)
Hydrogeologic CSM
Objective 1: Site Hydrology and Geology:
Aquifers Recharge/discharge Gradients/hydraulic head trends Hydraulic head boundaries Anthropogenic effects Barriers to flow Preferential flow Backfill and native fill distributions Are wells in the right locations to monitor SSCs and work practices?
Tested Hypotheses Bedrock Surface/Soil Thickness:
Surficial Aquifer Flow Net:
Bedrock Lithology:
Bedrock Aquifer Flow Net:
Evaluate SSCs and WPs that contain or could contain licensed material with a credible pathway to reach GW Identify all SSCs; examples: SFPs, outdoor tanks, buried pipes, foundation joints etc.
Identify existing leak detection methods for these SSCs: GWM wells, leak detection systems, integrity testing etc.
Identify WPs that could result in a leak, spill/release of lic. Material Evaluate for potential enhancements to leak detection systems or programs NEI 09-14 Underground pipe and tank inspection initiative:
- SSC Risk Rank = consequence X Susceptibility (all safety related piping and tanks)
Evaluate potential enhancements to prevent spills or leaks from reaching GW Identify tracking for corrective actions Establish a frequency for periodic review of SSCs/WPs Objective 2: Site Risk Assessment:
- credible pathway: single barrier between SSC/WP and environment
Objective 3: On-going Groundwater Monitoring Timely detection of inadvertent releases:
[Hydrology and Geology] + [Risk assessment] = Initial CSM Initial Hydrogeologic CSM becomes basis for GW monitoring well array and monitoring program Identify gaps in CSM (develop monitoring array and SSC/WP wells)
Establish sampling and analysis protocols Establish a formal written program for long-term monitoring (SAPs/SOPs)
Periodic review of lab(s) analytical capabilities/protocols Long term PM of wells Establish frequency [and triggers] for periodic review of the GWMP
- Program reviews and updates should trigger revision of Hydrogeologic CSM
Remediation, Record Keeping and D&D/SAFSTOR Impacts
- Objective 4: Remediation Establish a remediation protocol to prevent migration of lic. material off-site and to minimize decommissioning impacts *mitigation vs. remediation*
Mitigation: Reduce Threat, Remediation: Remove Threat
- Objective 5: Record Keeping Records of leaks, spills and remediation efforts are retained to meet the requirements of 10 CFR 50.75(g)
- Objective 6:
D&D/SAFSTOR Impacts
- CSM and Risk Ranking needs to align with new site conditions and changes
Part 3:
Program Oversight a.
Initial independent program self assessment b.
Assessment of GPI program every 5 years CSM review and update as necessary More frequent review of update in response to site changes/events c.
5-year assessments to review GPI objectives
- Provides a programmatic path to routing CSM updates and record keeping through D&D!
Applied Examples Common Data Environment (CDE) Use:
Applied Examples Climate change considerations
Triggers for CSM updates Structure Dewatering:
Structure Dewatering & Well Pumping:
Comments, Questions Matt Darois, CGWP, Corp. Environmental &
Engineering Manager Radiation Safety & Control Services Inc.
medarois@radsafety.com