ML20210C947
| ML20210C947 | |
| Person / Time | |
|---|---|
| Issue date: | 04/29/1987 |
| 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 8705060372 | |
| Download: ML20210C947 (3) | |
Text
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DISTRIBUTION Docket File WM-64 PDR/DCS WM-64/DLJ/87/04/17/0
' T01sen LLW Branch, WMLU APR 3 91987 URF0 r/f DGillen, WMLU FMiera, OR URFO:DLJ Docket No. WM-64 040WM064810E MEMORANDUM FOR:
Docket File No. WM-64 FROM:
Dawn L. Jacoby, Project Manager Licensing Branch 1 Uranium Recovery Field Office, Region IV
SUBJECT:
REQUEST TO DELETE THE PLASTICITY INDEX REQUIREMENT FROM THE SPECIFICATIONS FOR RADON BARRIER AND LINER CONSTRUCTION AT LAKEVIEW, OREGON
Background
Specification for Earthwork, Section 0200, 2.1.C.2.b. for the Lakeview, Oregon site states:
l
" Radon barrier materials shall consist predominantly of soils with l
classification of CL, MH or ML when classified in accordance with the requirements of ASTM D2487, and graded with maximum particle size of 2 inches and minimum of 50 percent passing No. 200 Steve.
Such material shall have a Plasticity Index (PI) of 10 or greater when tested according to ASTM D4318.
Compliance with these Specifications will be determined by the Contractor."
Paragraph 2.1.C.3 requires the geochemical / flow barrier liner material to be "similar to that for the radon barrier."
i Construction at the facility began in 1986.
Excavation of material from l
the disposal cell area was to be separated into fine and coarse stockpiles for use in liner and cover construction.
However, due to i
identification difficulties encountered in the field, the material was not separated and only one stockpile area was utilized.
Initial testing results from the stockpiled material indicated that some of the material did not meet the plasticity index (PI) requirement.
0705060372 870429 OFC go, waste NAME :
DATE :87/04/20 i
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WM-64/DLJ/87/04/17/0 APR s 91987 Discussion DOE has proposed (letter to URF0 dated February 6,1987) to delete the PI requirement from the construction specifications. Theirjustification for deleting the requirement is based upon the fact that the PI of a soil is not a direct measurement of the required design characteristics (permeability and radon diffusion) and is therefore not a governing test.
Representatives of the RAC and TAC determined during a site investigation that the stockpiled material would be acceptable for construction. As additional justification, 20 stockpile samples were laboratory classified and five were subsequently tested for specific gravity, Proctor compaction, and permeability.
Nine additional samples were selected by the evaluating group for classification, and were tested for specific gravity Proctor compaction and accelerated time permeability.
The conclusIondrawnfromthetestresultswasthattherangeofpermeability I
values were acceptable and that the stockpiled material was therefore suitable. Only three of the original twenty samples failed to meet the PI requirement and only one of the set of nine samples had a PI of less than 10.
As additional justification that design assumptions would be met, radon diffusion testing was reportedly performed on stockpiled material and the calculation for cracking potential was re evaluated assuming a PI equal to zero. Also, an interoffice correspondence letter from D. G. Summers was included that described the sampling and layering conditions of the stockpile materials.
The letter described the procedure that will be utilized to preclude the placement of " sand" in the fill.
Conclusions The staff is in agreement that the PI requirement does not ensure acceptable material in itself and that the requirement was intended to provide greater quality assurance and control.
Without an Atterberg limit determination, stockpiled material could not be classified in accordance with ASTM D2487.
Also of concern is the fact that gradation of the material is, like the PI, only an indication of a soils behavioral characteristics.
To base rejection or acceptance of material only on its gradation cannot be considered prudent engineering practice.
Additionally, it has been determined that soils with a PI less than 12 are particularly susceptible to frost action.
Although the data submitted indicates that the majority of the materials tested passed the PI requirement, the samples were taken from the surface OFC :
NAME :
DATE :87/04/29
WM-64/DLJ/87/04/17/0 APR 2 91987 i
I which, according to a sketch of the stockpile, should be fine grained material. Therefore, the undesirable " Sand" lenses which are known to exist in the stockpile may not have been encountered at the surface.
Without the PI requirement, sandy material that was not distinguishable i
from the fine grained soils during excavation and stockpiling may be placed in the fill.
Recommentation l
After reviewing the material submitted for the justification to change the specifications, it is felt that the deletion of the PI requirement is not in the best interest of the project.
It is agreed that the PI is only an index test that serves as an indicator of material characteristics.
The deletion of the test, however, will serve only to lower the confidence level of the material selected for fill.
k Dawn L. Jacoby, Project Manager Licensing Branch 1 Uranium Recovery Field Office Region IV Approved by:
kN M t
Edward F. Hawkift's, Chief Licensing Branch 1 Uranium Recovery Field Office, Region IV Case Closed:
040WM064810E OFC : URF0 URF0 0:
NAME :DJacoby/1v
- T01sen EHawkins
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DATE!87/04/29
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