ML20236A282
| ML20236A282 | |
| Person / Time | |
|---|---|
| Issue date: | 07/20/1987 |
| From: | Hawkins E, Jacoby D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| REF-WM-64 NUDOCS 8707280056 | |
| Download: ML20236A282 (2) | |
Text
l DISTRIBUTION Docket.Eile WM-64 PDR/DCS WM-64/DLJ/87/07/16/0
- T01sen FMiera, OR JUL 2 01987 LLW Branch, WMLU URF0 r/f URF0:DLJ Docket No. WM-64 040WM064840E MEMORANDUM FOR:
Docket File No. WM-64 FROM:
Dawn L. Jacoby, Project Manager Licensing Branch 1 Uranium Recovery Field Office, Region IV
SUBJECT:
COMMENTS ON REVISED SECTIONS OF REVISION 2 0F LAKEVIEW RAIP Section 6.1.3 has been revised to address the re-evaluation of the density test results from the nuclear gauge after a negative correlation with standardized results. The recommended allowable differences of 2 percent between gauge density results and the standard sand cone density results is reasonable.
Appreciable differences will result in retests of appropriate fill materials.
Section 6.2.1.1 has been added to th'e RAIP.
It will allow 20 percent of the fill material (one test out of every five) to fail the plasticity index (PI) requirement of 10 percent, although no material will be considered acceptable with a PI of less than 5 percent.
Classification (PI) testing is required for every 2,000 cubic yards of material.
Due to the problems encountered with separating materials during the stockpiling process and the identification of appreciable amounts of sand within the stockpile, this revision to the RAIP should not be accepted.
The PI of a material is an indication of the range of moisture contents over which a material remains plastic.
Therefore, a material with a low PI would have a tendency to behave like a viscous fluid or he in a semisolid state depending on a small increaqe or decrease in moisture content.
When a soil is in a semisolid statd, it will crack when deformed or will exhibit elastic rebound.
Not only does this make a soil difficult to work during construction, but would also raise concerns for the integrity of the barrier in long-term situations, i.e., 1000 years.
For example, the stockpile sample identified as TPR-5 has a reported PI of 5 percent, a 8707280056 870720 0FC :
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WM-64/DLJ/87/07/16/0 MNN
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liquid limit of 34 percent, and an optimum water content of 31 percent.
Specifications allow fill material to be placed up to 3 percent above optimum moisture and 1 percent below optimum moisture.
Therefore, this material could be placed at a moisture content ranging between the liquid limit (34 percent) and 1 percent above the plastic limit (30 percent).
Long-term moisture loss (which will occur) could result in undesirable field moisture contents well below the plastic limit.
According to their letter dated July 7,1987, DOE anticipated that the inclusion of this provision would " allow the use of most of the material on hand, and avoid the need to locate, evaluate and develop a new source of material." DOE indicated that the stockpiles would be " inspected visually...and tested for gradation to be certain minimum sands are placed." This assurance, however, does not affect our concerns regarding the use of the stockpiled material for cover. Visual inspection did not exclude the material from the stockpile, and gradation tests are to be performed for only every 2,000 cubic yards of material that will be placed. Without establishing that the stockpiled material is the best material reasonably available for the project, there is no reason to relax design and specification requirements to accommodate it.
Section 6.3.4, Radon Barrier Thickness Determination, was also added to the RAIP. The section provides a testing procedure for the top 20 feet of tailings placement to determine Ra-226 and Th-230 activity.
Twenty area samples shall be taken for analysis for every 2 feet of tailings.
This should provide a good bases for determining emission from the tailings.
It would be beneficial if the density and moisture content were determined for each sample analyzed.
/s/
Dawn L. Jacoby, Project Manager Licensing 8 ranch 1 Uranium Recovery Field Office Region IV h
Approved by:
Edward F. HaWkins, Chief Licensing Branch 1 Uranium Recovery Field Of fice,, Region IV s
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EHaw 87[p7/fp DATE :87/07/17
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