UE-27a Borehole End of Well Report - eDCRO - eDCRO

Document No: RVDC-1.01-026RPT
Revision 0

Rock Valley Direct Comparison (RV/DC)
UE-27a Borehole End of Well Report
August 2026

Prepared for:
U.S. Department of Energy
National Nuclear Security Administration
Defense Nuclear Nonproliferation Research and Development

Prepared by:
Geosciences Group
Defense Nuclear Nonproliferation Division
Global Security Directorate
Mission Support and Test Services, LLC
Nevada National Security Site

Document No: RVDC-1.01-026RPT
Revision 0

Acknowledgements
This Source Physics Experiment (SPE) research was funded by the National Nuclear Security Administration, Defense Nuclear Nonproliferation Research and Development (NNSA DNN R&D). The authors acknowledge important interdisciplinary collaboration with scientists and engineers from LANL, LLNL, NNSS, SNL and UNR-NSL.

Document No: RVDC-1.01-026RPT
Revision: 0

1.1

1.2

1.3

1.4

1.5

2.1

2.2

2.3

2.4

3.1

3.2

3.3

4.1

4.2

4.2.1

4.2.2

4.3

4.4

4.5

4.6

4.7

Document No: RVDC-1.01-026RPT
Revision: 0

5.1

5.2

6.1

6.2

7.1

7.2

Appendix A: Geologic Core Graphical Logs
Appendix B: Geophysical Logs

Document No: RVDC-1.01-026RPT
Revision: 0

List of Figures
Figure 1: Reference map showing location of Borehole UE-27a at the Nevada National Security Figure 2: Reference map of the Rock Valley Region, showing topography and historic boreholes. Test Well F (TWF) is labeled as United States Geological Survey (USGS) HTH F on this Figure 3: Map showing the drill site set-up at the RV/DC testbed, Area 27. The Corehole location Figure 4: Diagram of UE-27a. Borehole diameters are shown on the left and casing diameters on Figure 5: Modified drilling subcontractor's whiteboard showing sections of significance to drilling operations. Right: Charted drilling progress showing depth over time, GWS is Figure 6: Deviation survey for UE-27a. The left two columns show the azimuth and inclination in degrees, plotted by depth. The right shows a planar view of the borehole deviation Figure 7: General geologic map of the Rock Valley region showing GFM units. The map differentiates Quaternary and Tertiary Alluvium; however, the GFM groups Quaternary and Tertiary Alluvium into a single, undifferentiated layer. A-A’ Cross Figure 8: A-A' Cross Section showing geologic interpretation of the subsurface. The approx