ML24032A035

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Federal and NRC Guidance Updates on Radiological Survey and Dose Modeling
ML24032A035
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Issue date: 02/01/2024
From: Cynthia Barr, Chris Mckenney, Snead K, Bruce Watson
Division of Decommissioning, Uranium Recovery and Waste Programs, NRC/NMSS/DDUWP/RTAB, Environmental Protection Agency
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Federal and NRC Guidance Updates on Radiological Survey and Dose Modeling Cynthia Barr, Christepher McKenney, and Bruce Watson, US NRC Kathryn Snead, US EPA EPRI/NEI Decommissioning Conference Oceanside, CA January 30-February 1

Guidance Updates

  • Federal guidance updates

- MARSSIM Rev. 2

  • NRC guidance updates

- Interim Staff Guidance (DUWP-ISG-02)

- Update to NUREG/CR-7021

Federal Radiological Survey Guidance MARSSIM Rev. 2

Changes to MARSSIM Site-specific Scanning Surveys

Changes to MARSSIM Continuously Collected Data Image Credit: Oak Ridge Associated Universities.

Image Credit: PNNL-SA-157412, Pacific Northwest National Laboratory.

Changes to MARSSIM Scenario B 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0

2,000 4,000 6,000 8,000 10,000 Power, 1 -

True Surface Activity Concentration [Bq m-2]

Approximate AL DL

Other Changes to MARSSIM Measurement Quality Objectives

=

1 2

2 1 +

2 2

2 2 + +

2 2

NRC Guidance Updates

NRC Interim Staff Guidance-Subsurface Investigations

  • Two subsurface workshops were held July 2021 and May 2022 with over 160 and 120 participants, respectively
  • Technical topics included:
  • Geospatial tools for radiological survey design
  • Dose modeling for subsurface residual radioactivity
  • Consideration of elevated areas
  • NEI groundwater protection initiative
  • Characterization of basement substructures
  • Innovative technologies for subsurface characterization
  • Case studies and lessons learned
  • SC&A, Inc. (NRC contractor) issued a draft white paper which was discussed in the workshops
  • An interim staff guidance was prepared based on workshop findings and other information

https://www.nrc.gov/waste/decommissioning/whats-new.html Industry State Agencies Federal Registrants

Draft Interim Staff Guidance DUWP-ISG-02 Radiological Surveys and Dose Modeling of the Subsurface to Support License Termination Extends NUREG-1575 Multi-Agency Radiation Survey and Site Investigation (MARSSIM) to the subsurface--

addressing surveys of open excavations, reactor basement substructures, and materials planned for reuse among other topics

DUWP-ISG-02 Dose Modeling for Submerged Sources Addresses guidance gaps for use of commonly used decommissioning dose modeling codes to develop clean-up levels for unsubmerged and submerged sources, including basement substructures

DUWP-ISG-02 Dose Modeling for Existing Groundwater Contamination Addresses guidance gaps regarding adequacy of groundwater monitoring networks and assessment of risk from existing groundwater contamination

DUWP-ISG-02 Public Comments Issued in October 19, 2023, with a 60-day public comment period (88 FR 72112)

Comments were due December 18, 2023 12 comments were received including the following:

1. Level of survey needed for reuse of offsite materials
2. Need for and nature of site-specific support for risk-significant parameters
3. Adding realism to assessment of risk from existing groundwater contamination

DUWP-ISG-02 Next Steps A comment response document will be prepared along to accompany the final DUWP-ISG-02 which is expected to be published in late summer 2024.

The final DUWP-ISG-02 will be incorporated into the next revision of NUREG-1757, Volume 2, Rev. 2.

NUREG/CR-7021 and PNNLs Visual Sample Plan are also being updated.

You can find the ISG and other related reports on NRCs What's New in Decommissioning web site.

Thank you

  • For additional information please contact the following individuals:

Cynthia Barr, NRC/NMSS Cynthia.barr@nrc.gov Randall Fedors, NRC/NMSS Randall.fedors@nrc.gov