ML20247B194
| ML20247B194 | |
| Person / Time | |
|---|---|
| Issue date: | 03/20/1989 |
| From: | Heyer R, Rich Smith NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| REF-WM-39 NUDOCS 8903290310 | |
| Download: ML20247B194 (5) | |
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REGION IV URANIUM REcoV FIELD OFFICE DENVER, COLORADO l10225 MAR 2 01989 URF0:RSH Docket No. 40-WM039 040WM039230E MEMORANDUM FOR:
Docket File No. 40-WM039 FROM:
Ralph S. Heyer, Project Manager Uranium Recovery Field Office, Region IV
SUBJECT:
REVIEW OF JUSTIFICATION FOR APPLICATION OF SUPPLEMENTAL STANDARDS AT VICINITY PROPERTY GJ-97010-0T (WEST MAIN STREET)
Background
By submittal dated March 8, 1989, the Department of Energy (D0E) provided a final Radiological and Engineering Assessment (REA) which requested the application of supplemental standards on the contaminated area (s) for vicinity property GJ-97010-0T.
This REA is for an application for supplemental standards in a strip of land approximately 20 feet wide and 1,700 feet long adjacent to the south edge of West Main Street within the city limits of Grand Junction, Colorado.
The eastern boundary of this strip of land is the Denver and Rio Grande Western Railroad Co. right of-way, and the western boundary is the Colorado River.
The purpose of this assessment is to evaluate the extent of contamination in the area being considered for supplemental standards.
This assessment includes recommended remedial action, estimated volume of material to be removed, and estimated cost alternatives.
Discussion The application for supplemental standards pertains to mill tailings contamination surrounding the storm sewer on the south side of West Main Street.
The storm sewer is a 30-inch and 48-inch diameter concrete pipe, which lies within the city of Grand Junction right-of-way for West Main Street.
There were five alternatives examined in the REA.
They are summarized as follows:
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8903290310 890320 PDR WASTE WM-39 PDC i
2 MAR 2 01989 Alternative 1 Complete remediation with replacement of e/isting pipe.
Health Risk - Reduced to within EPA standards Construction Cost - $353,000 Estimated Volume of Contaminated Materials Removed - 3,459 cy Alternative 2 Complete remediation, hand excavation with pipe in place.
Health Risk - Reduced to within EPA standards Constr uction Cost - $534,000 Estimated Volume of Contaminated Materials Removed - 3,459 cy Alternative 3 Complete remediation, existing pipe removed and reused Health Risk - Reduced to within EPA standards Construction Cost - $296,000 Estimated Volume of Contaminated Materials Removed - 3,459 cy Alternative 4 Partial remediation by removal of tailings to a 30-inch depth Health Risk - Gamma exposure rates reduced to background levels, radon gas migration not controlled Construction Cost - $132,000 Estimated Volume of Contaminated Materials Removed - 1,829 cy Estimated Volume of Contaminated Materials Remaining - 1,630 cy Alternative 5 Application of Supplemental Standards (No Remediation)
Health Risk - No identifiable health risks Construction Cost - $0 Estimated Volume of Contaminated Materials Removed - O cy Estimated Volume of Contaminated Materials Remaining - 3,459 cy Radiological Data The area background is 15 pR/hr and 1.6 pCi/gm.
The highest gamma reading was reported at 139 pR/hr.
The exposure rate range at ground level, over the contaminated area, was reported between 15 to 139 pR/hr.
The average exposure rate at ground level, over the contaminated area was 50 pR/hr.
The Ra-226 concentration in the soil, in contaminated areas, ranged from
<1.0 to 277.9 pCi/gm.
The average Ra-226 concentration in the soil, in the contaminated area, was 77 pCi/gm.
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MAR 2 01989 I
I If the contamination is below or within 10 feet of a structure the radon daughter concentration in that structure was estimated at 0.0699 WL.
The data
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submitted supports the belief that the mill tailings were used during the construction of the storm sewer.
Health Risk Analysis The analysis of health risks was presented in the REA utilizing two comparisons.
First was the examination of long-term exposures based on a l
100 mrem per year exposure and second was an assessment of short-term unusual exposures based on a 500 mrem per year exposure.
The maximum gamma dose rate is 100 mrem / year to an individual member of the general public.
Doses which exceed 100 mrem / year are acceptable when the higher exposures do not persist for long periods and when the average annual dose over an individual's lifetime is expected to be less than 100 mrem / year.
The health risk analysis presented in the application described the worst case scenario based on the minimum background and maximum surface gamma rates that were measured, without consideration of the relative physical location of each.
DOE stated tnat in every case, the scenarios presented in the REA were described as unlikely but possible.
The scenarios did not create a model of likely situations but rather to present data that can be utilized to evaluate the pocential for a health hazard if the application was approved.
The maximum gamma exposure rate, above background, occurs in the area in front of 505 West Main Street and is equal to the worse case scenario.
The worst case scenario depicts occupation of a site for an average of two to three hours per day during a one year period.
DOE stated that it is unlikely that this situation would occur in an area so close to the street without considerable s
changes in land ownership and uses.
Conclusion l
I The DOE concluded that based on the examination of the health risks performed there appears to be no identifiable significant health risks should the application be approved.
There is no change in land use expected within the foreseeable future.
However, it was noted that there is a potential for future tailings migration from the West Main Street area.
The DOE, in the REA, recommended that a long-term tailings management, disposal, and migration control plan be developed and implemented.
The plan l
would address undiscovered deposits, deposits left in place through application of supplemental standards, and deposits that are not within existing inclusion boundaries.
Based on the above and my review of the subject REA and associated correspondence, Criterion "c" of 40 CFR 192.21 and the NRC's " Guidelines for Justifying the Use of Supplemental Standards," in 40 CFR Part 192, dated 1
c.
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4 MAR 2 01989 July 3, 1986, DOE satisfied the criteria deemed necessary to apply supplemental standards.
I recommend that' concurrence be granted for the application of' supplemental standards and that there be no removal of contaminated soils at the property designated as GJ-97010-0T-(West Main Street).
Ra S He
,. Project Manager j
Uranium Re ery Field Office i
Region IV Approved By. MA,1v m
R. Dale Sinith7Directdr U
Uranium Recovery Field Office i
Region IV l
Case Closed:
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MAR. 2 0 1989 l
WM39/230E/RSH/89/03/20/M
' DISTRIBUTION Docket File No..'40-WM39 j
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RHeyer-BFranz, RCPD, CO LLO Branch, LLWM URF0 r/f.
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