ML21319A229
| ML21319A229 | |
| Person / Time | |
|---|---|
| Site: | WM-00058 |
| Issue date: | 11/18/2021 |
| From: | Dennise Orlando NRC/NMSS/DDUWP/URMDB |
| To: | Kerl P US Dept of Energy (DOE) |
| Orlando D | |
| References | |
| Download: ML21319A229 (3) | |
Text
November 18, 2021 Mr. Paul Kerl, Supervisor Environment Team 1 U.S. Department of Energy Office of Legacy Management 2597 Legacy Way Grand Junction, CO 81503
SUBJECT:
U.S. NUCLEAR REGULATORY COMMISSION STAFF REVIEW OF THE U.S. DEPARTMENT OF ENERGY REPORT ENTITLED ANNUAL PERFORMANCE REPORT APRIL 2019 THROUGH MARCH 2020 FOR THE SHIPROCK, NEW MEXICO, DISPOSAL SITE DATED AUGUST 2021 (DOCKET WM-00058)
Dear Mr. Kerl:
I am responding to your letter, dated September 13, 2021, providing the U.S. Nuclear Regulatory Commission (NRC) staff with the U.S. Department of Energy (DOE) report entitled Annual Performance Report April 2019 Through March 2020 for the Shiprock, New Mexico, Disposal Site dated August 2021 (Agencywide Document Access and Management System (ADAMS) Package Accession Number ML21257A451). NRC staff is aware that pumping was suspended at the Shiprock site in April 2017 and, as such, the volume of groundwater extracted, and the amount of contaminant mass removed, has been sharply reduced. Therefore, NRC staff is interested in the effect the cessation of pumping might have on the concentrations of the constituents of concern (CoCs) and on the water table levels on the terrace. The report indicates that there have been some increases in CoCs in a few wells at the Shiprock site although these increases were slight and within historical observations. Based on our review of the report, we have the following comments.
New to this performance report are the results of the Mann-Kendall trend analysis results for floodplain wells presented in Appendix B. NRC staff finds this analysis a useful addition to the performance report. However, it is not clear why some of the wells listed did not show an increasing uranium concentration trend. For example, wells 0611, 0612, 0622, and 0855 show an upward trend since the suspension of pumping in 2017 as can be seen in the uranium time-concentration trends in Figure 13. None of the four wells are labeled as increasing after the Mann-Kendall trend test was completed (see Table B-3) even though Section 3.3.1 states Since the last reporting period, uranium levels increased markedly in two wells: central floodplain well 0622 and western floodplain well 0855. If the reason for this lies in the fact that the analysis was performed for lengthier time period, i.e., 2006 - 2019, than the time period at Shiprock with very little pumping, i.e., 2017 - 2021, then NRC staff would find the results of a Mann-Kendall trend analysis very useful for the shorter timeframe. NRC staff is aware that the data set for the 2017 - 2021 timeframe is much smaller, and that DOE may decide that it is too small for the Mann-Kendall trend analysis to be performed.
P. Kerl 2 In addition, NRC staff is interested in understanding why DOE decided to use the surface water features along Bob Lee Wash and Many Devils Wash as Contouring Control Points to produce the terrace water elevation contours in Figure 18. Has DOE concluded that the water in these washes are directly connected with the groundwater below (as opposed to disconnected streams or washes)? Has DOE concluded that it represents the water table of the terrace and, therefore, the groundwater elevation? If so, could DOE please provide the NRC staff with the technical basis documents supporting this conclusion.
In accordance with Title 10 of the Code of Federal Regulations Section 2.390 of the NRCs Agency Rules of Practice a copy of this letter will be available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records component of NRCs ADAMS. The ADAMS database is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html.
If you have any questions concerning the NRC comments, please feel free to contact me at 301-415-6749 or at Dominick.Orlando@nrc.gov.
Sincerely, Signed by Orlando, Dominick on 11/18/21 Dominick Orlando, Senior Project Manager Uranium Recovery and Materials Decommissioning Branch Division of Decommissioning, Uranium Recovery and Waste Programs Office of Nuclear Material Safety and Safeguards Docket No.: WM-58 cc: Shiprock List Serv
Ltr ML21319A229 NMSS/DUWP NMSS/DUWP NMSS/DUWP NMSS/DUWP OFFICE
/URMDB /RTAB /URMDB /URMDB NAME DOrlando DO HArlt HA RVon RV DOrlando DO DATE Nov 15, 2021 Nov 16, 2021 Nov 18, 2021 Nov 18, 2021