ML22136A110
| ML22136A110 | |
| Person / Time | |
|---|---|
| Issue date: | 05/11/2022 |
| From: | Thomas Aird Office of Nuclear Regulatory Research |
| To: | |
| Barr C | |
| Shared Package | |
| ML22117A070 | List: |
| References | |
| Download: ML22136A110 (17) | |
Text
NRC Overview Presentation Second Annual Subsurface Investigations Workshop May 11, 2022 Tom Aird, NRC Office of Nuclear Regulatory Research
- Reactor sites are being rapidly decommissioned instead of entering SAFSTOR
- Many complex decommissioning sites are expected to contain areas of residual radioactivity in subsurface soils and building structures
- These complex sites will need to be investigated/surveyed and a determination made as to the need for subsurface remediation and a final decision made on license termination Workshop Motivation
Todays Agenda Time Topic Speaker 12:00 pm Logistics and Welcome NRC:
Brett Klukan Jane Marshall 12:10 pm Opening Remarks
- 1 NRC Opening Remarks
- 2 NEI Opening Remarks NRC:
Tom Aird Cynthia Barr NEI:
Bruce Montgomery 12:40 pm Overview Presentations
- 3 Methodologies for Optimization of Survey Design
- 4 Statistical Methods for Subsurface Surveys to Support Decommissioning SC&A:
Carl Gogolak PNNL:
Deborah Fagan Jennifer Huckett 1:20 pm Discussion Period A All 2:00 pm Break 2:10 pm
- 5 Utilizing the Nuclear Energy Institute (NEI) 07-07 Industry Groundwater Protection Initiative as a Foundation for Addressing Subsurface Site Assessments
- 6 Subsurface Basement Modeling and Survey Methods RSCS:
Matt Darois Eric Darois 2:50 pm Discussion Period B All 3:20 pm
- 7 US DOE Challenges with Subsurface Investigation and Site-Specific Case Study DOE:
Amanda Anderson Brian Harcek 3:40 pm
- 8 Using Electrical Resistivity Tomography (ERT) and Other Geophysical Methods to Non-Invasively Inform Subsurface Investigations Related to Decommissioning PNNL:
Tim Johnson Fred Day-Lewis 4:00 pm Break 4:10 pm
- 9 Lessons Learned Identified during Independent Verification Activities ORAU/ORISE:
David King 4:30 pm Discussion Period C All 5:00 pm Adjourn
Last Years Public Workshop July 14 & 15, 2021 RES/NMSS held a public workshop on the technical basis for guidance on conducting and evaluating surveys of residual radioactivity in the subsurface soils of licensee sites. The NRC began to address this problem in NUREG/CR 7021, A Subsurface Decision Model for pupporti ng Environme ntal Compliance, issued January 2012.
Supporting Environmental Compliance, issued January 2012. https://www.nrc.gov/docs/ML2130/ML21300A378.pdf https://www.nrc.gov/docs/ML2130/ML21300A378.pdf
- NUREG/CR-7021 (January 2012)
-A Subsurface Decision Model for Supporting Environmental Compliance
- NUREG-1757, Volume 2, Revision 1 (2006)
-Consolidated Decommissioning Guidance: Characterization, Survey, and Determination of Radiological Criteria (Appendix G)
-Volume 2, Revision 2 was issued as a draft report for comment and contains updated guidance on subsurface surveys in Appendix G and J
- NUREG-1575, Revision 1 (2000)
-Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) contains guidance on final status surveys for surface residual radioactivity Prior or Existing NRC Guidance
Previous and Potential New Approaches A
B C
(A) Identify Potential Areas where Residual Radioactivity could be Present (B) Visualize Initial Borehole Sampling Results (C) Interpolate Data and Determine Probability of Exceeding a Threshold following Scoping (top) and Create a more Refined Map following Characterization (bottom)
Sequence Source: NUREG/CR-7021
Research Focus Areas Derived Concentration Guideline Levels for subsurface Stages of the Subsurface Decision Framework Geospatial Modeling Tools Geospatial and Statistical Methods Assessing Background and Use of MARSSIM Alternative Scenario B Evaluations of Large Soil Excavations and Soil Reuse Treatment of Uncertainty and Data Sufficiency Possible Treatment of Subsurface Elevated Areas and Hot Spots
Proposed Methodologies for Subsurface Survey Design and Data Analysis
--supporting remedial and license termination decision making--Subsurface Survey Sampling Design Subsurface Modeling Tools/Software Visual Sampling Plan (VSP)
SADA Bayesian ELLIPGRIDMarkov Bayes and Cokriging Bayesian ELLIPGRID Markov Bayes and Objective: add and test these (or other) statistical sampling techniques with existing subsurface modeling tools Objective: Other??
(or other) statistical sampling Figures: NUREG/CR
-7021** Please see draft white paper Subsurface Surveys and Characterization attached to this meetings public meeting notice on NRC website.
Reference:
-7021
- Please see draft white paper Subsurface Surveys and Characterization attached to this meetings public meeting notice on NRC website.
Reference:
ML22088A219 **
Contact Information Tom Aird, NRC/RES Thomas.aird@nrc.gov Cynthia Barr, NRC/NMSS Cynthia.barr@nrc.gov
Subsurface Guidance Development Cynthia Barr, Senior Risk Analyst, Office of Nuclear Material Safety and Safeguards Division of Decommissioning, Uranium Recovery, and Waste Programs Presentation at the 2nd Annual Subsurface Soils Workshop May 11, 2022
Current Technical Information and Guidance 11 Draft NUREG-1575, Rev. 2, Multi-Agency Radiation Survey and Site Investigation Manual (or MARSSIM--used for surface soils and building surfaces only)Draft NUREG 1757, Volume 2, Rev. 2, 2, Rev. 2,, Consolidated Decommissioning Guidance:
Characterization, Survey and Determination of Radiological Criteria CriteriaNUREG/CR 7021, A Subsurface Decision A Subsurface Decision Model for Supporting Environmental Compliance Compliance
Major Changes to NUREG-1757, Vol.
2, Rev. 2 12
- Dose modeling updates Dose modeling considerations and exposure scenarios for buried residual radioactivity (Appendix J)
Development of subsurface DCGLs (Appendix G)
Consideration of cumulative dose from multiple sources including surface and subsurface soils (Appendix G)
Radiological survey and dose modeling integration (Appendix G)
Major Changes to NUREG-1757, Vol. 2, Rev. 2
- Radiological surveys updates
- Surveys of open excavations or substructures (Appendix G)
- Surveys of soils/materials planned for reuse (Appendix G)
- Use of composite sampling (Appendix O) 13
NUREG-1757, Volume 2, Rev. 2, Final Issuance 14 Volume 2, Rev. 2, issued for public comment December 2020
Final publication is expected summer 2022
Guidance was added to address comments on need for additional subsurface guidance, including first workshop findings
Interim subsurface investigations guidance to be developed late 2022 or early 2023
Interim guidance will be issued for public comment prior to finalization
Interim guidance will be folded into the next revision of NUREG-1757, Volume 2 (Rev. 3)
Guidance Gaps
- Development of derived concentration guidelines levels (DCGLs) or clean-up levels for subsurface residual radioactivity
- Evaluation of the importance of subsurface elevated areas and need for derivation of DCGLEMCs
- Evaluation of geospatial data analysis and modeling tools including GIS and geostatistical tools
- Development of a technical approach for optimization of subsurface survey design, and to facilitate remedial and compliance decision-making
- Development of a technical approach for evaluation of soil excavations, basement substructures, and materials planned for reuse
Interim Subsurface Guidance Development and VSP Code Improvements Subsurface investigations interim guidance will consider
Need for update of current guidance
SC&As technical white paper and proposed methodologies
PNNLs scoping of Visual Sample Plan tools
Other technical information Visual Sample Plan (VSP) computer code improvements
Data analysis tools for continuously collected data
Statistical test parameters and power calculations 16
Final thoughts Guidance is available on subsurface surveys and dose modeling to derive clean-up levels in NUREG-1757, Volume 2, Rev. 2 Additional interim guidance is being developed Contracts to address remaining data gaps are being but in place (e.g., surveys of exposed surfaces in the subsurface)
Please check out our Whats New in Decommissioning web page to be kept informed of upcoming opportunities for public participation and release of future guidance documents https://www.nrc.gov/waste/decommissioning/whats-new.html 17