ML20141N679

Forwards Comments on Draft Remedial Action Plan & Working Environ Assessment for Tuba City Umtrap Project.No Major Problems Exist W/Proposed Remedial Action Plan

ML20141N679
Person / Time
Issue date:	02/26/1986
From:	Hawkins E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To:	Themelis J ENERGY, DEPT. OF
References
REF-WM-73 NUDOCS 8603170499
Download: ML20141N679 (4)

Text

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.. DISTRIBUTION Docket File WM-190

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DBangart, RIV HM-190/RFB/86/01/24/0 RBrich T01sen HRose PGarcia 73 FE8 2 6 26 EHawkins URFO:RFB Docket No. WM-MW- KHargis, NM 040WM190101E URF0 r/f John G. Themelis, Project Manager U.S. Department of Energy Albuqueruqe Operations Office P.O. Box 5400 Albuquerque, New Mexico 87115

Dear Mr. Themelis:

Staff review of the Draft Remedial Action Plan and working document Environmental Assessment for Tuba City have been completed. As we agreed, our review consisted of a broad overview of the documer.ts looking for " fatal flaws," unaddressed areas and sufficiency of basic data and information. To sumarize the enclosed comments, there appeared to be no major problems with the proposed remedial action. The comments tend to address more specific technical questions and issues that should not drastically affect the overall plan. At this point, there does not seem to be much value in meeting to go over these comments. If you feel that a meeting would be beneficial, please let us know. However, we should plan to meet when more detailed designs are submitted for review.

Should you have any coments or questions, please contact Mr. Randy Brich of my staff on FTS 776-2811.

Sincerely, Or1r.icn1 Etsmed !!y Nurd F. Han f nn Edward F. Hawkins, Chief Licensing Branch 1 Uranium Recovery Field Office Region IV

Enclosure:

As stated cc: F. Bosiljevac, DOE B. Mason, TAC B603170499 860226 PDR WABTE WM-73 PDR

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' NRC COPMENTS ON DRACT REMEDIAL ACTION PLAN AND WORKING DOCUMENT ENVIRONMENTAL ASSESSMENT FOR TUBA CITY UMTRA PROJECT-

' Radon' Barrier - DRAP i

1. Page 19. Table'3.2

a. The average Ra-226 concentration.for the total windblown contaminated soils is shown as 33.8 pCi/g. However, Page~18, last sentence of Section 3.2.3 states that the average Ra-226 concentration for the windblown areas is 55.5 pC1/g. Please clarify this apparent discrepancy and provide the bases for the p  : correct value.

2. Page B-33, ~ Table 3.5.1 - Please state the order for the tailings layers when calculating required local cover thickness.

3 Pages B-35 and B-55, Sections B.5.7 and B.5.13, respectively, refers the reader to Section B.5 for long-term moisture: calculations.

Review of Section B.5 does not reveal the referenced calculations.

Accordingly, please provide the necessary information.

4. Page D-25 Section D.2.2.4 - Emergency spill ponds - The text states that no Th-230 analyses were performed on soil samples obtained from the-emergency spill pond. Therefore, it is impossible to determine if Th-230 is a problem in these areas. Note that on Page 36 of

' Addendum D1, BFEC states that equivalent-thorium concentrations are high'in several soil samples from the evaporation ponds.

5. Since characterization of the Th-230 concentration in the upper contaminated layer for the Collins Ranch disposal site has been conducted and Th-230 concentrations were considered for Canonsburg, presumably under Section 40 CFR 192.21(f), please provide your i rationale for not conducting similar measurements for this site.

Surface Water Hydrology and Erosion Protection - ORAP Appendix B, Section B.8

1. Provide the bases for the design of the energy dissipation structures that will be constructed at the ditch outlets.

Information should be provided regarding the design bases that will be'used to determine:

a. riprap size, especially with regard to turbulence and j velocities in energy dissipation structures, and i

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b. exit velocities, especially with regard to the ability of natural soils to withstand velocities produced at the downstream end of the structure.

2. Recognizing that the rock source may not yet be determined, information should, however, be provided to document the proposed durability specifications that the rock will meet and the measures that will be taken to oversize the rock if the proposed durability specifications cannot be met.

Ground Water - DRAP Page D-232

1. Please state what monitoring wells were utilized to establish the extent of vertical contamination in the vicinity and down gradient of.the (process mill) site.

2. Areas of extensive vertical contamination at and/or below monitoring well screened intervals should be shown in map view and explained in greater detail in order to accurately delineate the plume.

3. Also, since vertical contamination is suggested, it is possible that monitoring has not detected maximum plume migration in a down gradient direction due to shallow depth of screened intervals for monitoring well. Accordingly, please clarify the extent of vertical contamination.

Ground Water - EA Page 43 It is not clear whether the estimation of contaminant plume migration (present) is based on monitoring well detection or interpretation of data. If monitoring wells were used to determi'ie plume migration distance, they should be identified with further explanation and map location shown.

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g NRC SUPPLEMENTAL COMENTS ON DRAP FOR TUBA CITY UMTRA PROJECT

1. Page 18. Section 3.2.3, last paragraph, second sentence - Highway 64 is not marked on Figure 3.3. Please clarify the location of the area discussed.

2. Page 18, Table 3.1

a. The total on-pile average radium-226 concentration of 862.3 pCi/g appears to be in error when one performs the volume-weighted calculaticn for the piles and subpiles.

[(689,226c.y.)(959.2pCi/g)+(92,100c.y.)(26.5pci/g)]+

781,326 c.y. = 849.3 pCi/g

b. The total on-pile volume (piles plus subpiles) is 781,326 c.y.,

not 781,339 c.y. as shown.

3. Page 44, Section 4.4.4, second paragraph, third sentence:

How will the rock cover increase the long-term soil moisture content of the radon barrier cover? Please cite a reference which supports this statement.

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