ML21208A220

2-4-Elevated Areas or Hots Spots in the Subsurface

ML21208A220
Person / Time
Issue date:	07/15/2021
From:	Cynthia Barr NRC/RES/DRA
To:
Aird, Thomas - 301 415 2442
Shared Package
ML21208A206	List: ML21208A212 ML21208A213 ML21208A218 ML21208A220 ML21208A222 ML21208A223
References
Download: ML21208A220 (6)

Text

Subsurface Soil Surveys Public Workshop Cynthia Barr Senior Risk Analyst July 15, 2021

Elevated Areas or Hot Spots in the Subsurface

Consideration of Elevated Areas in the Subsurface

• Elevated areas in subsurface soils may be less important than on the surface (the total inventory may drive the dose from the groundwater pathway)

• Elevated areas may be a more important consideration for intrusion scenarios

Alternative DCGL Approaches for Elevated Areas

• In the case that open excavation surfaces are available for scan survey, DCGLemcs could be based on the intrusion scenarios, or

• The DCGLw could be developed based on the most limiting scenario

Considerations for Elevated Areas in the Subsurface

• On the surface, scan surveys are typically used to detect elevated areas between sample locations.

• What should the rigor of the survey be to detect elevated areas where there are no exposed surfaces to scan in the subsurface?

• Could the survey be designed to detect elevated areas of a certain size based on dose modeling?

• The sample size could be based on the probability of detecting an elevated area of a certain size.

Thank you!