ML20245L004
| ML20245L004 | |
| Person / Time | |
|---|---|
| Issue date: | 05/26/1989 |
| 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 8907050338 | |
| Download: ML20245L004 (5) | |
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i5 hatacg,. UNITED STATES - +: p NUCLEAR REGULATORY COMMISSION O REGION IV URANtUM RECOVERY FIELD OFFICE ) 80x 25325 .,g DENVER, COLORADO 80225 l MAY 2 61989 i URF0:RSH Docket No. 40-WM039 040WM039330E i l I 1 MEMORANDUM FOR: Docket File No. 40-WM039 FROM: Ralph S. Heyer, Project Manager Uranium Recovery Field Office, Region IV 1 i
SUBJECT:
REVIEW 0F JUSTIFICATION FOR APPLICATION OF SUPPLEMENTAL STANDARDS AT VICINITY PROPERTY GJ-97012-0T (HORIZON DRIVE SEWER-INTERCEPT 0R)
Background
I By submittal dated April 11, 1989, the De7artment of Energy (DOE) provided a i final Radiological and Engineering Assess,nent (REA) which requested the application of supplemental standards on the contaminated area (s) for vicinity ) property GJ-97012-0T. i The limits of the area being considered in the REA are described as a strip of land that is generally 20-feet wide and is centered over the Horizon Drive sawer interceptor line. The section of sewer line begins approximately at the North edge of the right-of-way for Interstate 70 and goes in a southwesterly. direction in existing rights-of-way and easements to 600 feet east of the center of the 25 Road and F Road intersection (north of.Pomona School). The REA only addressed areas not currently under paved surfaces. 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 Horizon Drive sewer interceptor pipeline which runs from I-70 to near F Road and 25 Road. There were five alternatives examined in the REA. They are summarized as i follows: OFoh 8907050338 890526 ' I PDR WASTE WM-39 PNU w__________
.....L..-. ~ ~ ~ - W 1 2 - MAY 2 61989 l Alternative 1 Complete remediation (Pipe replacement in the same trench) f Health Risk - Reduced to within EPA standards 1 Construction Cost - $1,533,929 Estimated Volume of Contaminated Materials Removed - 17,000 cy Alternative 2 l Complete remediation (Hand excavation with pipe in place) .{ Health Risk - Reduced to within EPA standards Construction Cost - $1,610,729 j Estimated Volume of Contaminated Materials Removed - 17,000 cy Alternative 3 Complete remediation TPipe replacement in new trench) Health Risk - Reduced to within EPA standards i Construction Cost - $1,885,339 i Estimated Volume of Contaminated Materials Removed - 17,000 cy Alternative 4 1 Partial remediation (Tailings removal to a 30-inch depth) -{ Health Risk - Gamma exposure rates reduced to background levels i Construction Cost - $474,965 j Estimated Volume of Contaminated Materials Removed - 7,200 cy Estimated Volume of Contaminated Materials Remaining - 9,800 cy I l Alternative 5 No remediation (Application for supplemental standards)- l Health Risk - See " Health Risk" Section to this report Estimated Volume of Contaminated Materials Remaining - 17,000 cy Radiological Data The area background is 12 pR/hr and 3.1 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 12 to 369 pR/hr. The average exposure rate at ground level, over the contaminated areas, was reported as 43 pR/hr. The Ra-226 concentration range in soil, in the contaminated areas, was reported as 3.1 to 217 pCi/gm. The average Ra-226 concentration in the soil, in the contaminated area, was 56.6 pCi/gm. Health Risk Analysis ) The analysis of health risks was presented in the REA utilizing two comparisons. The first was an examination of long-term exposures based on an exposure of 100 mrem / year exposure and the second was an assessment of short-term unusual exposures based on a 500 mrem / year exposure. The maximum
a..-. ~. 4 - 3 MAY 2 61989 1 1 gamma dose rate is 100 mrem / year to an individual member of the general public. l Doses which exceed 100 mrem / year are acceptable when the 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 this application for supplemental standards has compared the dose rates measured at ground level with the recommendations of the ICRP and DOE regarding waist level exposures. This proc The maximum gamma exposure ra edure ensures a conservative evaluation. te, above background, occurs along the Independent Ranchman's Ditch. This worst case scenario requires occupation of a site for an average of one hour per day during a one year period to obtain the 100 mrem dose. A possible health risk exists in this area because of the potential land use change to residential areas with backyards adjacent to or 1 l over the contaminated area. The worst case scenario, in the street f right-of-way area, requires occupation of a site for an average of'one hour per day. This scenario is unlikely to occur. Conclusion The DOE concluded that based on the examination of the health risks performed there appears to be no identifiable significant health risks should this application for supplemental standards be approved; except in the Independent Ranchman's Ditch and from First Street to Seventh Street. There is no change 1 in land use expected within the foreseeable future. The DOE stated that change i in land use in any other area along the sewer line is expected within the foreseeable future. i The DOE, in the REA, does recommend that since the tailings in the area between First and Seventh Streets is for 30-inches of tailings it should be removed during the remediation of the adjoitiing parent property. The remaining tailings below a 30-inch depth in the area will fall under this supplemental standards application. There is a potential for future tailings migration from the Horizon Drive i Interceptor area. The potential tailings migration pathways are; (1) reconstruction activities associated with future upgrading of Horizon Drive from Seventh Street to G Road; and (2) maintenance and repair operations required for the remaining useful life of the sewer line. Application of supplemental standards was requested pursuant to Title 40 CFR 192.22 Criteria "a" and "c" for all arear except that mentioned for the top 30-inches of soil / tailings from First to Seventh Streets along the Independent Ranchman's Ditch. The cost of remediation is excessive when no significant health risks exist in the remaining portion of the sewer line. Criteria "a" should be applied for the section of sewer line on Horizon Drive in the I-70 right-of-way where two 13.2 KV buried electric lines lay over the sewer lines. A long-term tailings management, disposal, and migration control plan should be developed and implemented. The plan should address undiscovered deposits, deposits left in place through the application of stcpplemental standards, and deposits that are not within existing inclusion boundarks. -____n_-----
) 1 j MAY 2 61989 4 Based on the above and my review of the subject REA and associated correspondence, Criterion "a" and "c" of 40 CFR 192.21 and the NRC's i " Guidelines for Justifying the Use of Supplemental Standards," in 40 CFR l Part 192, dated July 3,1986, DOE satisfied the criteria deemed necessary to i apply supplemental standards. I recommend that concurrence be granted for the j application of supplemental standards and that there be no removal of ~ contaminated soils at the property designated as GJ-97012-0T (Horizon Drive l Sewer Interceptor). Ra1 S. Hey Project Manager Ura f um Rec v ry Field Office l Region IV l Approved By: )
- Dale Smith, Director
( Uranium Recovery Field Office i Region IV l Case Closed: 040WM039330E i l
MAY 2 61989 WM39/330E/RSH/89/05/11/M DISTRIBUTION Docket File No. WM-039 PDR/DCS ABBeach, RIV RHeyer BFranz, RCPD, CO LLO Branch, LLWM URF0 r/f 1 l 1 l l t l l l l CONCURRENCE: DATE: RHeyer/URF0/db P 6-24 % PGarcia/URF0 / 14 T RDSmith/URF0 e ff f I ( l l _ _ _ - -}}