ML20148E324
| ML20148E324 | |
| Person / Time | |
|---|---|
| Issue date: | 05/27/1997 |
| From: | Gillen D NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Rael G ENERGY, DEPT. OF |
| References | |
| REF-WM-66 NUDOCS 9706030066 | |
| Download: ML20148E324 (4) | |
Text
_ _ _ _ _ . . . _ _ _ _ _ .. . _. . -
( May 27, 1997
, Mr. George Rael, Director ;
U.S. Department of Energy Albuquerque Operations Office
. . ERD /UMTRA P.O. Box 5400 i Albuquerque, NM 87185-5400 l
SUBJECT:
SUMMARY
OF THE MEETING AND SITE VISIT TO NATURITA/URAVAN, COLORADO j ON APRIL 23, 1997
Dear Mr. Rael:
~
, The purpose of this letter is to provide a summary of the meeting and site \
1 visit by the Nuclear Regulatory Commission staff to the U.S. Department of 4
Energy (D0E) Uranium Mill Tailings Remedial Action (UMTRA) Project site at
, Naturita/Uravan, Colorado, on April 23, 1997.
4 DOE and its contractors conducted tours of both the processing site at
] Naturita and the disposal cell at Uravan. The primary purpose of these tours was to familiarize the staff with the Naturita site and to provide the staff with a better understanding of the surface water hydrology and erosion protection features at the Uravan disposal site. The staff also visited the quarry where DOE proposes to obtain rock for the cover of the disposal cell.
NRC staff comments were discussed with DOE at the meeting following the site I
, visit, and these comments are provided in Enclosure 1. These comments are
- numbered to conform to the previously-used comment numbering system for this site. It was agreed that comments 27, 29, and 30 were understood and that DOE could respond adequately to them. To respond to Comment 28, DOE suggested, j and it was agreed, that a panel consisting of expert DOE and contractor 4 personnnel would be convened to develop revised specifications for the rock. i Enclosure 2 is the meeting attendance sheet.
l If you have any questions concerning this subject, please contact Mr. Robert ,
] Carlson, the Project Manager for the Naturita site, at (301) 415-8165.
4 Sincerely, j (Original signed by) 4
. Daniel M. Gillen, Assistant Chief Uranium Recovery Branch Division of Waste Management
- g 60 g g 970527 Office of Nuclear Material Safety gLf
~
Enclosures:
As stated cc: W. Woodworth, DOE Alb p
S. Hamp, DOE Alb E. Artiglia, TAC Alb DISTRIBUTION (w/ encl): File Center NMSS r/f URB r/f PUBLIC CCain, RIV AGarcia TJohnson JHolonich CNWRA (w/o encl): MFederline DOCUMENT NAME: S:\DWM\ URB \RDC\NATVISIT.COM 0FC URB E U RD ., , 6 NAME Mon DGiMe DATE [ /27/97 /f T/?!!/97 N OFFICIAL RECORD COPY j(' y 7 300079 . RETURN TO REGULATORY CENTRAL FILES
i NRC STAFF COMMENTS ON SURFACE WATER HYDROLOGY AND EROSION PROTECTION MEASURES AT NATURITA/URAVAN The following comments were discussed with DOE at the April 23, 1997, meeting following the Naturita/Uravan site visit. These comments will be added to the existing list of open issues for the site and will follow the existing numbering sequence '.r tracking purposes.
- 27. COMMENT: Potential for Hydraulic Jump in Channel #1 DISCUSSION:
There appears to be a potential for a hydraulic jump to occur _in Channel
- 1, just upstream of the road crossing. Since the culverts under the road are designed for a lesser flood, water will flow over the road during larger events such as the probable maximum flood (PMF). Because this will increase the depth of flow in the channei upstream, a hydraulic jump may occur where shallow flows from the steep channel slope meet the larger flow depths.
ACTION NEEDED:
DOE should revise the riprap design in this channel to accommodate this phenomenon, provide calculations to justify that a hydraulic jump will not occur, or provide calculations to show that the existing design can ,
withstand a hydraulic jump. )
- 28. COMMENT: Specifications For Oversized Sandstone Rock DISCUSSION:
Additional specifications should be provided for the gradations of the oversized sandstone rock. These specifications can be adapted for the sandstone already produced (regardless of size), but the specifications should provide minimum sizes and thicknesses of the rock.
Specifications should also be provided for placement of the oversized sandstone and for verification of the layer thickness At a minimum, some written standard / guidance for the rock placement should be developed. This standard may consist of visual calibration and assessment for selection and emplacement of the rock, with smaller rocks being used to fill the voids between the larger rocks, etc.
The specifications should also address how the sandstone will be quarried, evaluated, and selected in the field. The staff suggests that a competent geologist be available to verify that the rock types being produced and placed are similar to those previously approved, recognizing the varying quality of the different types of sandstone in the area.
Enclosure 1
\ .
i l
ACTION NEEDED:
l DOE should provide additional specifications or rewrite the current
- specifications, as indicated above. i i
1
- 29. COMMENT: Interim and Long-Term Grading and Effect on Erosion Protection )
i DISCUSSION:
]
l The NRC staff's inspection at the top of the slopes surrounding the l disposal cell indicated that loose dirt had been stockpiled, apparently by the Cotter Corp. The staff expressed concern that Cotter Corp. could a
change the grading at the top of the slope, thereby affecting the-erosion protection designs down gradient. Other erosion protection i concerns expressed by the staff included: any existing potential for e,
the larger inflow gullies (ie., especially near and along Channel #2) to change course during a large flood event, causing flows to impact the
- channels at locations other than those designed for (eg., the large sandstone dissipation area along Channel #2 is designed for a gully in that. location only); gully movem . due to erosion; and erosion effects near the top of the slopes, and its down gradient consequences.
ACTION NEEDED:
i DOE should verify the acceptability of its current design for erosion protection, based on specific grading to be finished at a later date by
! Cotter Corp. DOE should execute a formal agreement with Cotter Corp. to ensure that its design would be acceptable for any future grading plan selected, l
- 30. COMMENT: Erosion Effects on the Adjacent Title II Disposal Cell DISCUSSION:
Based on NRC staff observations at the downstream end of Channel #2, it appears that runoff will be directed toward the adjacent Title II cell, potentially causing erosion at the toe of the cell (near the edge of the canyon). Potential solutions discussed during the site visit included straightening Channel #2 (requiring a cut through rock), and/or construction of a protective rock berm with very large riprap along the channel.
ACTION NEEDED:
DOE should revise the Channel #2 erosion protection design or alignment so that the integrity of the adjacent Title II cell is not threatened.
_3
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i
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Enclosure 2