ML20236S747
| ML20236S747 | |
| Person / Time | |
|---|---|
| Issue date: | 07/21/1998 |
| From: | Joseph Holonich NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Rael G ENERGY, DEPT. OF |
| References | |
| REF-WM-66 NUDOCS 9807270202 | |
| Download: ML20236S747 (10) | |
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o July 21,1998 Mr. George Rael, Director i
U.S. Department of Energy Albuquerque Operations Office ERD /UMTRA P.O. Box 5400 Albuquerque, NM 87185-5400
SUBJECT:
REVIEW OF NATURITA REMEDIAL ACTION PLAN
Dear Mr. Rael:
The U.S. Nuclear Paqulatory Commission (NRC) staff has completed its review of the Naturita, Colorado final Rem ial Action Plan (RAP) for both the processing and disposal sites, which l
1 were transmitted by U.S. Department of Energy (DOE) via transmittal letters dated April 10 arid June 12,1998. Enclosed are the NRC staff comments, which cover the technical areas of groundwater hydrology, surface water hydrology and erosion protection, and soil clean-up and radon attenuation. All other technical areas of the Naturita RAP were considered acceptable by the NRC staff.
If you have any questions concerning this subject, please contact Mr. Robert Carlson of my staff at (301) 415-8165.
Sincerely, i
[D. Gillen for]
Joseph J. Holonich, Chief Uranium Recovery Branch Division of Waste Management Office of Nuclear Material Safuy and Safeguards
Enclosure:
As stated
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- , July 21, 1998 Mr George Rael, Director U.S. Department of Energy Albuquerque Operations Office ERD /UMTRA ,
P.O. Box 5400 l' Albuquerque, NM 87185-5400
SUBJECT:
. REVIEW OF NATURITA REMEDIAL ACTION PLAN
Dear Mr. Rael:
l The U.S. Nuclear Regulatory Commission (NRC) staff has completed its review of the Naturita, 1 Colorado final Remedial Action Plan (RAP) for both the procesting and disposal sites, which 1 were transmitted by U.S. Department of Energy (DOE) via transmittal letters dated April 10 and !
June 12,1998. Enclosed are the NRC staff comments, which cover the technical areas of groundwater hydrology, surface water hydrology and erosion protection, and soil clean-up and rsdon attenuation. All other technical areas of the Naturita RAP were considered acceptable by the NRC staff.
l
-If you have any questions concerning this subject, please contact Mr. Robert Carlson of my i staff at (301) 415-8165. j Sincerely, M. N Joseph J. Holonich, Chief A :
j Uranium Recovery Branch Division of Waste Management Office of Nuclear Material Safety and Safeguards i
Enclosure:
As stated i cc: R. Cornish, DOE Alb F. Bosiljevac, DOE Alb !
E. Artiglia, TAC Alb l
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U.S. NUCLEAR REGULATORY COMMISSION STAFF REVIEW COMMENTS ON THE U.S. DEPARTMENT OF ENERGY REMEDIAL ACTION PLAN FOR NATURITA, COLORADO The following U.S. Nuclear Regulatory Commission (NRC) staff comments are in reference to its review of the U.S. Department of Energy (DOE) Remedial Action Plan (RAP) for the Naturita, Colorado, Uranium Mill Tailings Remedial Action Project site, transmitted by cover letters on April 10 and June 12,1998. NRC staff comments are in the technical areas of groundwater hydrology, surface water hydrology and erosion protection, and soil clean-up and radon attenuation. All othe-'echnical areas of the Naturita RAP were considered acceptable by the NRC staff. 1 When responding to the NRC staff comments, DOE should ensure it maintains the current numbering system used below to facilitate proper tracking and closure of issues.
i HYDROLOGY 1 COMMENT: Concentration Limit for Strontium and Tin at Upper Burbank Disposal Site I
DISCUSSION- t i
RAP Table 3.1 of Appendix C identifies groundwater quality concentration limits for strontium and tin at the Upper Buroank Disposal site. ' According to this table, these i limits were derived from ground water quality samples collected at the disposal site from Wells CM-93-1 and CM-93-2. However, data on strontium and tin concentrations are not reported in the tables of site water quality data (i.e., tables of " Groundwater Analyses, CM-93-1, CM-95-2, Burbank Repository", Appendix B). Therefore, it is not clear how concentration limits for these parameters were derived.
ACTION NEEDED; DOE should provide on-site water quality data collected for strontium and tin to establish the concentration limits in RAP Tcble 3.1 of Appendix C, or describe how data to derive concentration limits for strontium and tin will be obtained.
SURFACE WATER HYDROLOGY AND EROSlON PRQTECTION I
- 2. COMMENT: Delineation of Drainage Areas )
l DISCUSSION: i i
Based on the NRC staffs review of information provided by DOE in Construction Resolution Revision (CRR) No. 25 and remnt site visits to the Upper Burbank disposal cell, it appears there may be some potentia) for drainage areas of the various drainage channels to be different from that assumed in DOE's flood analyses. It is not apparent that the drainage areas assumed in DOE's present calculations are correct, or would be ;
so in the future (i.e., if grading modifications occur). This issue is, imporiant for the following reasons: (1) DOE intends to use smaller rock in the channels, but the flows in ;
Enclorure E___________-_---_-___
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these channels could actually be larger, depending on the drainage area; (2) DOE assumes that the interceptor ditch could overtop (if filled by sediments), whereby any increases in overtopping flow could affect the toe design at the base of the steep slope, and therefore could affect the design of the downstream drainage ditches; and (3) flows could be larger at various locations entering the diversion channel, resulting in the need to design an interceptor channel and large sandstone riprap for flow concentrations.
7 ' ACTION NEEDED:
DOE should provide revised analyses that clearly delineate the drainage areas of the various channels and should consider the potential for these drainage areas to change I in the future. Unless specific drainage area configurations can be identified, DOE ,
should assume worst-case scenarios and provide detailed calculations and drawings of 1 various possible drainage area configurations. Additionally, DOE should provide the following:
i a) design of the riprap for the interceptor and diversion channels; b) design of the interceptor channel for sediment accumulation, and analyses of the potential for the channel to overtop and allow concentrated flood flows to affect the design of the downstream channels, aprons, and toes; and c) design of the large sandstone and side slope riprap for concentrated ficws produced by different possible drainage area configurations.
- 3. - COMMENT: : Design of Sandstone Benches DISCUSSION:
Based on NRC staff review of CRR No. 25, site visit observations at the Upper Burbank {
disposal cell, and discussions with DOE and contractor personnel, the sandstone bench area on the upstream side of the interceptor channel will need some design modifications to prevent undesirable flow patterns from occurring (e.g., sudden drop- l offs). It appears that if the sandstone bench is placed as currently designed, flood flows will not transition smoothly onto the side slope riprap, and there is a potential for erosion of the riprap to occur.
ACTION NEEDED:
DOE should revise the design and placement of the sandstonn bench upstream of the l interceptor charmel. As discussed and agreed during a recent NRC staff site visit, DOE should provide a revised design that allows for no sudder, drop-offs or undesirable flow l transitions in this area. DOE should provide revised drawings indicating these changes.
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3 SOIL CLEANUP & RADON ATTENUATION
- 4. COMMENT: Long-Term Moisture Value of Windblown Material DISCUSSION:
RAP Section 6.2.1 of the Naturita Remedial Action Selection (RAS) Report (Processing Site) indicates that the long-term moisture value of windblown material was not measured, but was assumed to be similar to mill yard material (i.e., the same value of 12 percent was used). However, RAP Calc-010 of Appendix F indicates that four l
i samples of windblown material were measured to have a long-term moisture value of 13 I percent. RAP Sections 6.2.2 and 6.2.4 of the RAS also mention radon model values that are obsolete. '
ACTION NEEDED:
DOE should revise RAP Section 6 of the RAS to reflect the values used in the current radon flux model, which appears to be Calc-010 of Appendix F.
- 5. COMMENT: Missing information in Section 6.3 of the RAS DISCUSSION:
RAP Section 6.3, page 6-4 of the RAS (Processing Site)is titled " Evaluation of Radon Barrier;" however, there is no evaluation. Also, this section does not refer to another part of the RAP as to where the evaluation can be found.
ACTION NEEDED:
DOE should provide the aforementioned evaluation for RAP Section 6.3 of the RAS, or revise the existing section accordingly. l
- 6. COMMENT: Missing Information in Attachment 4 DISCUSSION:
In Attachment 4 (Processing Site) the title pages for the sections labeled " Soil Verification Using Cobbles-to Fines Correction" (OP-003 4) and " Uranium Cleanup and Verification at Naturita" (RAC-OP-007) indicate the inclusion of DOE /NRC correspondence; however, this information was not included.
ACTION NEEDED:
DOE should either provide the referenced correspondence or revise the existing title pages accordingly.
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- 7. COMMENT: Conflicting Data in Attachments 1 and 4 i
DISCUSSION: )
l Both Attachments 1 and 4 (Processing Site) contain conflicting data in the sections ,
labeled " Contaminated Material Excavation - Cobbles-to-Fine Ratio" (Calc.17-730 I
- 02) and " Cobbles-to-Fine Test Pit Analysis," respectively. Specifically, both sections !
contain Calc. 17-730-03-02; however, Sheet 7 of Attachment 4 was not updated from the previous version of the calculation.
ACT!ON NEEDED:
DOE should revise both referenced sections in Attachments 1 and 4 in order to be consistent, or delete any duplicable data that is conflicting in either section.
- 8. COMMENT: Incomplete Historical Information and Missing Evaluation in Attachment 4 DISCUSSION: {
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The section labeled " Cobbles-to-Fine Test Pit Analysis" in Attachment 4 (Processing Site) contains a table of uranium and radium data from the cobbles-to-fines test pits.
This data sheet was also provided to the NRC in 1996 as part of a response to issue 19 )
regarding the characterization of uranium and Th-230. However, DOE's evaluat!on of the data was not provided. Based on its review. the NRC ctaff determined the data demonstrates that tailings material exists at 6 to 9 feet deep, or that the in-situ mineralized materialis not in equilibrium. Additionally, Appendix B of the " Cobbles-to-Fine Test Pit Analysis" section contains data (see Sheet B-9) showing Th-230 concentrations from the test pits; however, there is no indication of the sample depth or the corresponding Ra-226 value.
ACTION NEEDED:
DOE should provide a discussion in the referenced section regarding the site history of !
process-related uranium and Th-230, and where they may exist at higher concentration levels (pCi/g soil) than the Ra-226. An evaluation of all uranium and Th-230 data for the site should also be provided.
- 9. COMMENT: Incomplete Data and Missing Supplemental Standard Application I DISCUSSION:
The section labeled " Radiological Data Collected During Excavation of Uranium Under )
Former Mill Site" in Attachment 4 (Processing Site) consists of a DOE trip report, dated I l July 28,1997, that includes some analytical data indicating Area 2 was excavated to the l water table; however, elevated uranium levels were still present. Additional testing is recommended in the report. Mention is also made in the report where State of Colorado staff feel that adapting the generic thorium protocol for uranium is inadequate.
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ACTION NEEDED:
DOE should provide the supplemental st; ,ard application for uranium in the RAP arid j include the additional data collected - nell as the health analysis per its commitment in Section 6 of the RAS Report. DOE D dd also indicate where in the RAP it proposes to adapt the thorium protocol for uranium.
- 10. COMMENT: Calculation 17-730-01-02 (Excavation Extent & Depths, Volume, Ra-226) in Attachment 1 DISCUSSION:
Appendix 0 of Attachment 1 (Processing Site) contains estimated Ra 226 concentrations for windblown Areas F and G. However, there are elevated levels (32 to 213 pCi/g) at depths of 12 to 42 inches. Based on these depths, this does not appear to be windblown.
ACTION NEEDED:
DOE should explain why there is elevated Ra-226 at depths greater than 1-foot in these
" windblown areas," and why the full depth of the contamination was not characterized.
- 11. COMMENT: Calculation 17-730-02-04 (Proposed Supplemental Standards Areas) in Attachment 1 DISCUSSION:
The summary of proposed areas for Supplemental Standards is on Sheets 2 and 3 in Attachment 1 (Processing Site). Comparison to the previous version of this calculation indicates that windblown Area B is no longer mentioned.
ACTION NEEDED:
DOE should indicate if the Supplemental Standards area in Area B is encompassed by the state right-of-way for the highway (NT-058), or if the contamination was removed.
- 12. COMMENT: Conflicting Supplemental Standards Information in Attachments 1 and 4 DISCUSSION:
The proposed Supplemental Standards area (Processing Site) for vicinity property (VP)
NT-065 on sheet 16 of Attachment 1 (Calc.17-730-02-03) do not match the same Supplemental Staridards area delineated on the map in Attachment 4. It is not clear l which map is correct.
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6 ACTION NEEDED:
DOE should revise the maps in Attachments 1 and 4 to ensure that the Supplemental Standards area for VP NT-065 is consistent and accurate.
- 13. COMMENT: Missing Supplemental Standards Information in Attachment 4 DISCUSSION:
The section labeled " Supplemental Standards Areas for Naturita Processing Site and Surrounding Vicinity Properties" in Attachment 4 (Processing Site) contains a map indicating areas proposed for Supplemental Standards - one of which includes a small area around power poles near the gas line within the former tailings area. The associated calculation does not address this area.
ACTION NEEDED:
DOE should provide the necessary information to include the referenced area as part of its proposed Supplemental Standards area.
- 14. COMMENT: Missing Supplemental Standards Information in Attachment 1 DISCUSSION:
In Appendix C of Attachment 1 (Processing Site), Sheets C-17 and C-20 indicate that VP NT-065 Areas E and G contain windblown contamination that averages 111 and 46 pCilg Ra-226, respectively. Additional Ra-226 data for Areas E, F, and G are in Calculation 17-730-01-02, which indicates contamination extends to 42 inches in depth or beyond.
ACTION NEEDED:
When DOE provides the Supplemental Standards application for VP NT-065, the discussion of Areas E and G should consider if the depth of the elevated Ra-226 levels are due to in-situ material, or provide an explanation why there is contamination greater than 2 feet deep. Additionally, DOE should provide a map clearly indicating the property lines for VP NT-065 and the excavated portions of Areas E, F, and G, and include all Ra-226 data as appropriate.
- 15. COMMENT: Missing and Conflicting Supplemental Standards Information in Attachment 1 DISCUSSION:
l Sheets 9 and 10 of Attachment 1 (Processing Site) indicate that Supplemental Standards are proposed within 5 feet of the gas line in Area E. Area E appears to be part of VP NT-065, but the gas line is not listed under this property. Also, Sheet B-21 of I
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Appendix B indicates that there will be no excavation within 10 feet of the gas line. In
-contrast, Sheet F-2 of Appendix F (phone record dated November 11,1992) indicates that excavation must be by hand 3 feet on either side of the line.
ACTION NEEDED:
DOE should indicate what property the gas line is on and confirm that the discussion on Sheets 3 and 10 of Attachment 1 is correct in stating that Supplemental Standards will be applied to the area 5 feet on either side of the gas line.
- 16. COMMENT: Missing and Conflicting Data in the RAS and Attachment 4 DISCUSSION:
Table 1.1 of the RAS (Disposal Site) lists contaminated material types and volumes at the Naturita site. The section labeled " Site-Specific Hazardous Constituents"in Attachment 4 (Processing Site) provides a more comprehensive list of hazardous -
materials at the Naturita site. There appears to be a discrepancy in volume amounts for some hazardous constituents between the two sections of the RAP. Also, DOE has provided little or no discussion in either RAP section as to how disposal of this contaminated material has met regulatory, safety, and environmental requirements.
ACTION NEEDED:
DOE should provide some discussion in both referenced sections of the RAP regarding hazardous waste disposal, and show how this disposal met regulatory, safety, and environmental requirements. DOE should also update disposed volume amounts in all relevant portions of the RAP.
- 17. COMMENT: Conflicting information in Sections 6.2 and 6.4 of the RAS DISCUSSION:
In Section 6.2 of the RAS (Disposal Site), it is unclear in the fourth paragraph as to what thickness of radon barrier will be placed on the top slope of the disposal cell (Section 6.4 states there will be the same thickness on the top and sides).
l ACTION NEEDED:
DOE should revise the fourth paragraph of RAS Section 6.2 so that it states the cover layers and thicknesses are the same for the top and side slopes. )
- 18. COMMENT: Incorrect References in Sections 6.3 and 7.0 of the RAS !
- DISCUSSION:
In Section 6.3 of the RAS (Disposal Site), the second line indicates the wrong reference L_=_-___-______-___-___-_ ___-_-_________=_ _ _ _ _ _ _
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for the RADON code. It should appropriately reference "NRC 1989." Also, Section 7.0 !
of the RAS should be revised to replace the NRC 1984 reference with " Calculation of Radon Flux Attenuation by Earthen Uranium Mill Tailings Covers," NRC Regulatory -
Guide 3.64, July 1989. The 1984 document discusses the RAECOM code.
! ACTION NEEDED: .
i- l L iDOE should revise Sections 6.3 and 7.0 to incorporate the correct reference as
!- mentioned above.
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- 19. COMMENT: Inconsistent Radon Attenuation Data r
i L DISCUSSION:
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l in Section 6.3 of the RAS (Disposal Site), the last sentence indicates that radon flux l ' code input parameters are presented in Appendix F, NAT-CALC-010. However, Section 6.3.4 presents densities and specific gravity input values for the former tailings pile area and the windblown material that don't match the values used in NAT-CALC-010.
ACTION NEEDED:
DOE should ensure that parameter values presented in the radon attenuation section l ~ match values used in the radon flux modeling calculation.
- 20. COMMENT: Unreadable Map in Appendix I DISCUSSION:
l Sheet 10 of RAP Appendix I (Disposal Site)is a xerox copy of a folded map. The copy of this map is unreadable in this state.
ACTION NEEDED:
DOE should provide a full copy of the map.
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