ML20155E434
| ML20155E434 | |
| Person / Time | |
|---|---|
| Issue date: | 03/21/1986 |
| From: | Olsen T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Hawkins E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| REF-WM-22 NUDOCS 8604170603 | |
| Download: ML20155E434 (3) | |
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DISTRIBUTION Docket File WM-022 PDR/DCS DBangart, RIV tlM-022/TT0/86/03/21/0 T01sen URF0 r/f LLW Branch, WMLU IIAR 211986 URF0:TTO Docket No. Wit-022 MEMORANDUM FOR: Edward F. Hawkins, Chief Licensing Branch 1 Uranium Recovery Field Office, Region IV FROM: Thomas T. Olsen, Project Manager Licensing Branch 1
SUBJECT:
REVIEW 0F REMEDIAL INVESTIGATION REPORT AND FEASIBILITY STUDY FOR COTTER URANIUM MILL SITE FEBRUARY 1986 Review of the Cotter Mill Site remedial action documents suggest two insupportable conclusions. First, that aquifer restoration strategies and/or remedial action designs for the site can be determined based upon insufficient and/or limited field and sampling data. Second, that modeling will in some way substantiate or gap inadequacies inherent in the field investigation data pertinent to the millsite and vicinity.
The general approach for developing aquifer restoration strategies and selecting the most appropriate one for meeting site specific needs is, '
for the most part, based on systematic procedure.
Foremost in any systematic procedure for the purpose of aquifer restoration is the assemblage of information on the hydrogeologic characteristics of a site. This involves the characterization of the
- a. e subsurface where the problem exists. First, a description of the '
hydrogeologic characteristics of the site allows for a better understanding of the magnitude of the problem. Second, a thorough hydrogeologic investigation will not totally delineate the limits of the i problem, but will aid in estimating the transport and impact of the pollutant in the subsurface.
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WM-022/TT0/86/03/21/0 Information for a hydrogeologic site characterization is best obtained through a well coordinated field and sampling program. Areas of needed information and their basis are as follows:
- 1. Geologic environment and geotechnical soils investigation -
, Determination of the types of soils is important for establishing
' both the capacity for the pollutant (si to move.through the subsurface and feasible restoration alternatives.
- 2. Soil physical and chemical characteristics - each soil type l
identified in the geologic and geotechnical investigation will be characterized both physically and chemically._ Physical properties give information on workability and mechanics, which relate to pollutant movement and filtering. Chemical properties give information on soil attenuation characteristics, such as adsorption and precipitation, which relate to restoration strategies and methods.
- 3. Depth to ground water and bedrock - depth ground water and bedrock will give information on water levels, aquifer type, gradient anomalies, utilization of monitoring well type, screen determination, containment strategy, etc.
4 Ground water flow patterns and volunes - the flow patterns and volume of ground water impacted will dictate the actual physical placement of alternative restoration measures. Also, the volume of water affected will dictate the scope of potential cleanup measures.
- 5. Recharge and rates - identification of recharge and rates will play an important role in aquifer protection plans and rate of pollutant movement.
6 Aquifer characteristics - identification of aquifer characteristics will be essential for any analysis of ground-water flow and
, pollutant transport. This information is extremely important if ground-water modeling studies are to be utilized in a study. Some of the parameters that need to be determined for proper calibration and use of models are: aquifer type, mechanics, hydraulic conductivity, dispersion coefficients, storage coefficient (specific yield),etc.
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- 7. Background water quality data - backgrour.d water quality data are important to determine the severity of the problem and the appropriate remedial action.
When a comprehensive field investigation is completed, all acquired data is analyzed. At this point, modeling usually can be utilized to expand on the field investigation and data interpretation. However, modeling that is based on insufficient or limited data should be used only in that light.
To be most effective, the user of any model must have a thorough understanding of the specific aquifer studied. The use of modeling in this context should be limited with respect to data as it relates to the actual exis<ing environment.
It seems a bit inappropriate to be basing aquifer restoration strategy and cleanup methodology on a modeling approach such as presented in this report.
The feasibility part of the study lists costs estimates for alternative cleanup methodology. These costs vary with each type of restoration plan or combination of plans.
A decision made on the the engineering and cost effectiveness of alternative restoration measures at this time would be premature at best. l Further field work is needed to more thoroughly characterize the site and vicinity. This is necessary to make well informed decisions on aspects as critical as cleanup methodology and costs involved with restoration measures.
The determination of a remedial action strategy based on a limited field investigation and modeling approaches is highly suspect with regard to the Cotter flill Site Cleanup. It is neither adequate in terms of site characterization, remedial action strategy determination or cost effectiveness.
/s/
Thomas T. Olsen, Project Manager Licensing Branch 1 Uranium Recovery Field Office Region IV
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