ML20210C304
| ML20210C304 | |
| Person / Time | |
|---|---|
| Issue date: | 04/27/1987 |
| From: | Hawkins E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | James Anderson ENERGY, DEPT. OF |
| References | |
| REF-WM-64 NUDOCS 8705060151 | |
| Download: ML20210C304 (2) | |
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DISTRIBUTION Docket. File WM-64 PDR/DCS WM-64/DLJ/87/04/22/0
(' EMiera, OR APR 2 71987 LLW Branch, WMLU DGillen, WMLU URF0 r/f URF0:DLJ Docket No. WM-64 040WM064820E James R. Anderson, Project Manager Uranium Mill Tailings Project Office U.S. Department of Energy Albuquerque Operations Office P.O. Box 5400 Albuquerque, New Mexico 87115
Dear Mr. Anderson:
My staff has completed their review of the interim evaluation of radon barrier thickness for the embankment at Lakeview, Calculation No. 13-729-08-00, dated March 2, 1987, and their comments are enclosed.
In summary, the major concern of the staff is the type of material that the contractor has selected to use for cover construction.
Based on the information we have available, we could not concur in the cover design as proposed, due to the use of this material.
If an alternate borrow 3
source is not selected, additional testing and extensive discussion and justification will be required before the proposed material would be considered acceptable for use in the cover.
Should you have any comments or questions, please contact Tom Olsen of my staff on FTS 776-2813.
Sincerely,
[7 f Edward F. Hawkins, Chief Licensing Branch 1 Uranium Recovery Field Office Region IV
Enclosure:
As stated Case Closed:
040WM064820E t
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D DATE :87/04/22 8705060151 870427 PDR WASTE PDR EPM
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c UMTRA DOCUMENT REVIEW FORM SECTION 1 Site:
Lakeview Date: April 22, 1987 Document:
Interim Evaluation of Radon Barrier Thickness Commentor: USNRC, URF0 Comment:
The major concern of the URF0 staff is the type of material that the contractor has selected to use for cover construction.
Silts, in l
general, are avoided for engineering projects as they are universally described as " inherently unstable" because they tend to become quick when saturated, are difficult to compact, are highly susceptible to frost heave, and are highly erodable.
The construction specifications require that the material be compacted to 100 percent of standard Proctor at or above optimum which would very likely create virtually impossible construction conditions.
As a case in point, we were informed that difficulty was encountered meeting liner specifications of 95 percent of standard Proctor at or below optimum.
As would be expected for this type of material, the reported laboratory test results indicate a great deal of dispersion in soil properties. The contractor has noted the uncertainty of soil properties and has recommended " additional evaluation" by verifying the 15-bar moisture and specific gravity with additional laboratory testing.
They did not address the wide range of permeability results at 95 percent and 100 percent of standard Proctor maximum dry density. On several samples, the permeability actually increased with the increase in compactive effort.
This phenomenon is not in agreement with design assumptions i
associated with the liner and cover systems. Also noted to be lacking in the submittal was testing to identify the shrinkage characteristics of the material.
Please address the above concerns and describe what measures of conservatism will be used in the final design if an alternate borrow source is not selected.
The final design of the cover system should j
utilize reasonable, documented soil properties for placement and l
long-term conditions.
To facilitate the review process, the referenced data, in its entirety, should be included with the submittal.
It is our understanding that testing is being performed to validate the 1985 emanation fraction (Reference 2 on your calculation sheets) of the contaminated material in addition to the soils laboratory testing outlined in the submittal.
Results of this additional testing should also be submitted for our review.
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