ML20148F924
| ML20148F924 | |
| Person / Time | |
|---|---|
| Issue date: | 02/11/1988 |
| From: | Tokar M NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Fliegel M NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| REF-WM-62 NUDOCS 8803280323 | |
| Download: ML20148F924 (3) | |
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RIFLE MEM0 DIf M MEMORANDUM FOR: Myron Fliegel, Section Leader Operations Branch Divisioa of Low-Level Waste Management and Decomissioning FROM: Michael Tokar, Section Leader Technical Branch Division of Low-Level Waste Management and Decomissioning
SUBJECT:
GE0 TECHNICAL ENGINEERING COMMENTS ON THE PRELIMINARY DESIGN FOR THE RIFLE, C0 UMTRA SITES.
Enclosed are the geotechnical engineering coments on Volumes IV and IV of the calculations for the Rifle, C0 UMTRA Site, Phase 11 Prelininary Design. Derek Widmayer of my staff performed this review.
Michael Tokar, Section Leader Technical Branch Division of Low-Level Waste Management and Decomissioning
Enclosure:
As stated
, DISTRIBUTION:
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1 URANIUM MILL TAILINGS REMEDIAL ACTION PROJECT (UMTRAP)
RIFLE, COLORADO SITE GE0 TECHNICAL ENGINEERING REVIEW 0F PHASE 11 PRELIMINARY DESIGN DOCUMENTS Documents Reviewed: Calculations, Volumes IV and V (dated: November,1987.)
Reviewed by: Derek A. Widmayer, Civil Engineer, LLTB REVIEW COMMENTS GT/7 - Young's Modulus for Tailings In Calculation No. 06-525-09-00, there is a statement that no triaxial testing of compacted tailings materials has been done, and therefore, assumptions are made regarding the parameter values needed to calculate the Young's Modulus for l these materials. However, results from triaxial tests on tailings materials are reported in Figures D.4.54 through D.4.58 in the dRAP. This conflict should be resolved, preferably by additional triaxial testing that is l recomended in staff coment GT/3.
GT/8 - Material Geotechnical Characteristics Following the review of the dRAP and of all Volumes of Calculations for the Phase II Preliminary Design of the Rifle, C0 UMTRA tailings embankment, it must be noted that considerable inconsistencies are present in the descriptions of and the characterizations of the subpile materials, offpile contaminated materials, and the windblown tailings which will be disposed of in the embankment.
In the dRAP, subpile materials are described, along with tailings materials, as "onpile and subpile contamination." Also, in the dRAP, contaminated materials that are near the existing piles and the former mill locations are considered as "off-pile" contamination. Within this material will be some small patches of windblown tailings that are near the aforementioned locations. Windblown tailings are considered a separate type of contaminated material, and are so described.
In the Phase II Preliminary Design, these materials are not characterized clearly in these same categories. In Calculation No. 05-525-05-00, Geotechnical Characteristics, the off-pile and subpile materials are characterized together, while the tailings are characterized separately. In Calculation No. 06-525-09-00, "Settlement Analysis," the materials are characterized in the same divisions as the dRAP. Windblown tailings are not separately characterized in either calculation. These inconsistencies cause confusing use of material geotechnical properties which need to be resolved.
2 First, since the off-pile contaminated materials are to be placed in the embankment as a wholly separate layer, they need full characterization. The current Phase II Preliminary Design documents use only assumptions regarding the properties of this material.
Second, the subpile materials need to be correctly considered together with the tailings materials for disposal in the embankment, and they require additional characterization, as previously discussed in comment GT/4.
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