ML26040A014
| ML26040A014 | |
| Person / Time | |
|---|---|
| Issue date: | 02/06/2026 |
| From: | Hayes K NRC/NMSS/DDUWP/URMDB |
| To: | Shafer I US Dept of Energy (DOE) |
| References | |
| Download: ML26040A014 (0) | |
Text
From:
Kevin Hayes To:
Shafer, Ian Cc:
Douglas Mandeville; Sam Cohen; Lifeng Guo
Subject:
NRC Review of 2024 Verification Monitoring Report for the Slick Rock, Colorado, Processing Sites (Dated June 2025)
Date:
Friday, February 6, 2026 3:21:00 PM Hello Ian,
The NRC has completed its review of the 2024 Verification Monitoring Report for the Slick Rock, Colorado, Processing Sites submittal,dated June 2025(ADAMS Accession No. ML25209A573). The submittal was received in July 2025.
The NRC comments on the submittal are presented below:
At Slick Rock - East Processing Site, the uranium concentrations in off-site monitoring well 0311, located on the opposite side of the Dolores River from the former processing site, have exceeded the UMTRCA MCL for the constituent over the past 20 plus years of monitoring (see Figure 8 in the submittal). The well has exhibited an increasing uranium concentration trend over that time period with the highest uranium concentration (0.21 mg/L) reported in 2023, during a period of river flooding in the site area. NRC has noted that monitoring wells downgradient of the 0311 monitoring well have not been sampled during this period of increasing uranium concentrations, with the last sampling event in downgradient monitoring wells 0328 and 0329 conducted in 2001, according to the DOE-LM GEMS web application. NRC recommends downgradient sampling for uranium be included in future sampling events (as appropriate) to confirm the current extent of the dissolved plume.
At Slick Rock - West Processing Site, the submittal notes the historical presence of a BTEX dissolved plume in the vicinity of the 0319 monitoring well. Although, benzene remains significantly elevated above the MCL for the constituent, a decreasing trend has been observed over the 20 plus year monitoring period (see Figure 22 in the submittal).
NRC has noted that no wells downgradient of the 0319 monitoring well have been sampled for benzene (or the remaining TEX constituents) since 2002, according to the DOE-LM GEMS web application. In order to confirm the current extent of the BTEX dissolved plume at the site, NRC recommends sampling of downgradient wells, such as well 0320 and others (as appropriate), for BTEX in future sampling events.
These comments can be addressed in the next Verification Monitoring Report. No separate response to the NRC is required.
If you have any questions regarding NRCs review, please feel free to contact me.
Best Regards,
Kevin
Kevin R. Hayes, P.G., CPG, GISP Hydrogeologist Uranium Recovery and Materials Decommissioning Branch Division of Decommissioning, Uranium Recovery, and Waste Programs Office of Nuclear Material Safety and Safeguards U.S. Nuclear Regulatory Commission Phone: 301-415-0549 E-mail: Kevin.Hayes@nrc.gov