ML20059N382

Advises of Termination of Review of Naturita Draft Remedial Action Plan & Provides Comments Requested During 901002 Telcon

ML20059N382
Person / Time
Issue date:	10/05/1990
From:	Lohaus P NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS)
To:	Matthews M ENERGY, DEPT. OF
References
REF-WM-66 NUDOCS 9010120157
Download: ML20059N382 (11)

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007 0 5 tm Mark L. Matthews, Project Manager-Uranium Mill Tailings Remedial Action Project Office i

U.S. Department of Energy Albuquerque Operations Office.

P.O. Box 5400 Albuquerque, NM 87115

Dear Mr. Matthews:

As you are aware, DOE, due to budget considerations and a reordering of site priorities, requested that NRC terminate the review of the Naturita draft Remedial Action Plan and cancel plans for the scheduled informal site visit i

and meeting.

In compliance with DOE's request the NRC staff has terminated j

the review of the draft RAP and those comments available at that point i

were provided to your staff during a conference call on October 2,1990.

The completion of the conference call and transmittal of tha enclosed comments concludes the NP.C staff review of the draft Remedia' Action Plan for the i

Naturita site.

i The comments provided during the conference call, where available l

in written form, are enclosed with this letter for DOE consideration l

in preparing the Naturita areliminary final Remedial Action Plan. When et'11 ring these comments tie following caveats should be kept in mind: 1) thee NRC reviewers preparing the comments did not have the benefit of a site l

visit which can effect the validity of some comments; 2) the cossnents

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generated are not to be considered formally transmitted consnents requiring DOE response; and 3) the comments are not considered all encompassing.

l If you have any questions, please contact either M. Fliegel at FTS 492 0555 or S. Wastler at 492 0582.

Sincerely, l

(SIGNED) PAULH.LOHAUS Paul H. Lohaus, Chief Operations Branch Division of Low. Level Waste Management and Deconsnissioning, NMSS pe i

cc:

M. Abrams, DOE /A1 RBangart " g y JGreeves JAustin JSurmeier PLohaus Distribution:

JXennedy MFliegel DGillen MThaggart GGnugnoli LLWM r/f BJagannath TLJohnson ABc Mh, RIY RHall, RIV/URF0 PDR YES X

ACNW YES X

• See Previous Concurrence SUBJECT AB3 TRACT: INFORMAL COMENTS ON THE NATURITA DRAFT REMEDIAL ACTION PLAN 4V /

OFC :LLOB*

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NAME:SWastler

MFliegel

PLohaus DATE:10/05/90

10/05/90

10/05/90 SW/RFL/INF COMMENTS OFFICIAL RECORD COPY igm 9010120157 901005 PDR WASTE WM-66 PDC

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N SW/RFL/INF COMMENTS Msrk L. Matthews P'roject Manager Urahium Mill Tailings Remedial Action Project Office Albuquerque Operations Office P.O. Box S400 s

Albuquerque,NM 87115 Dear Mr. Mat As you are aware, TQE, due to budget considerations and a reordering of site priorities, requested that NRC terminate the review of the Naturita draft Remedial Action Plan ah cancel plans for the scheduled informal site visit and meeting.

In compliahce with DOE's request the NRC staff has terminated the review of the draft RAPsand those comments available at that point were provided to your staff during a conference call on October 2,1990.

The completion of the conference call and transmittal of the enclosed coments concludestheNRCstaffreviewobthedraftRemedialActionPlanforthe Naturita site.

The comments provided during the confereoce call, where available in written form, are enclosed with this latter for DOE consideration i

in preparing the Naturita preliminary finaTNRemedial Action Plan. When utilizing these comments the following caveatt should be kept in mind: 1) the NRC review >rs preparing the comments did nbt have the benefit of a site visit which can effect the validity of some com qnts; 2) the comments generated are not to be considered formally transmitted comments requiring DOE response; and 3) the comments are not considered at encompassing.

If you have any questions, please contact either M. F egel at FTS 492-0555 or S. Wastler at 492-0582.

Sincerely, Paul H. Lohaus, Chief Operations Branch

' Division of Low-Level Waste Management and Decomission. ng cc:

M. Abrams, 00E/A1 YMC Distribution:

RBangart JGreeves JAustin JSurmeier PLo(M(/fAc,p //

aus JKennedy MF11egel DGillen MThaggart GGnugnoli LLW PDR YES X

ACNW YES X

BJagannath TJohnson LLOB r/

SUBJECT AB5 TRACT: INFORMAL COMRuiiS ON Tli TURITA DRAFT REMEDIAL ACTION PLA i /, A D

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-The ' attached com/nents or questions have resulted f rom 1thel NRC.'sf review of 1the LNatdrita draf t" Remedial Action': Selection -Report m(RAS).1 lUnder

.StreamliningLagreement,3, NRC isito provide verbal-~ comments on-the draf ts RASiat? a a si tec vi sit meeting. - These informal comments arelbeing.

provided'to DOE,an/a convunience but shouldinot-be: considered'farmallyt

-- t ransmi tted ' comments, t nor.chall,-they be-considered-as"al W 7

E icncompensing.' The NRCistaff does not expect < DOE to-provi'd -formal.-

rocponses to the': individual commenta/questiens, but to -takejthesei c.

commentsLinto account in the preparation >of the final' RAS.-

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The di scussi-on of : the. salt anticlines'and'their ascociated

. faults as presented in'the' RAP seems! contradictory.. For'exemple,

-on pago 35 in the first paragraph, DOE statesf that the salt' anticlines have apparently.exp#rienced movement in theLQuaternary,1and may be capable of movement;today..Then in anLapparent. contradictory; statement on page.40,' DOE states that itLin.unlikely.that instability-of the salt anticline would occurfduring' the! design lif e of the cell as a result of salt _ flowage or tectonic activity.-

Then in tablef4.1, f ault group ' 1' is l considered. capable. and f assigned a 7.0 maximum magnitude, while at.the bottom offpage'53; DOE discusceu a study by ~

Wong et'al. that states that.the. maximum? magnitude f or L events related -

to = sal t ilowage f rom -mining _ or ' natural causes in appreximately 3.O.

DOE-needs to provide. a more complete;_di scussion1 of; theE sal t anticlines and how they ef f ect.:the geologic stabi_lity _ of: the) site.

2.-

DOE has not provided a diucussion ~ of L the ef f ects en the site of oathquakes associated with adjacent tectonic provinces.

3.

.On page 50,: DOE used the term capable-f ault but.in brackets

-implied the term to mean " capable; of activity within the' design =lif e of the. disposal cell".

Table 4.1 ! al so uses '"Poto itial for design-fault" instead of. capable fault.

This term'has a specific'. definition.

. i os-defined on page'2 of the RAP and'should.be.used accordingly.--

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l DERFT NATURITA R17 i

Review commants - Everossology l

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DOE indicates that at the processing site, the strong-upward-vertical hydraulic gradient between the alluvial j

aquifer and the Salt Wash aquifer (i.e., 0.040 ft/ft) and j

the large thickness and low hydraulic conductivity of the l

confining unit (i.e., the Brushy Basin Member) separating i

the two aquifers should result in no downward migrstion of groundwater.

Accordirigly only two wells were installed, at a

the site, into the Salt Wash aquifer.

Both of these wells I

are considered by DOE, in characterizing the water quality of the aquifer, to be up-gradient wells.

DOE is correct in their assessment about the small possibility of downward migration of groundwater, if it-is assumed that the confining units have similar characteristics throughout the site, which has not been proven or supported.- Accordingly, I recommend that DOE install at least one additional monitoring well within the Salt Wash aquifer to further characterize groundwater quality conditions.

This well should be drilled in the.a'rea of where the tailing were formerly located.

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i 2.

In characterizing the water quality in the alluvial and the i

Salt Wash aquifers at the processing site, DOE did not test for nitrite even though it is one of the constitutes listed-in Table 8.1 of the Technical Approach Document (TAD).

No explanation is given as to why it was not tested for.. DOE should either test for nitrite or provide justification for why no testing is needed.

3.

DOE indicated that from 1977 through 1979, tailings at the-processing site were removed te a new heap leaching reprocessing plant located along Colorado State Highway 90, about three miles southwest of the intersection of State-I Highways 141 and 90; however, no information is provided on whether or not this site should be included in consideration with the processing and disposal sites, and whether or not this site is contaminated.

DOE needs to clarify this issue.

4.

In describing the groundwater use within the area of the-processing site, DOE' admits that there are two wells down-l gradient from the site, but indicates that there is no l

potential for contamination of these wells.

It is unclear as to whether the basis for this assessment is 1) because of the wells location with respect to the river; 2) because of:

the walls are pumping from different aquiferar or 3) because-the wells are at a great distance from the site (note: no map is provided of the wells location with respect to the processing site).

DOE needs to clarify this issue by 1) providing a map of the well locations with respect to the processing sitar 2) identify which units the wells are l

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rccoiving thoir w0t0r frca; cnd 3) cl00rly ototo th3 bacio.

for their conclusion that thera is no potential for l

contamination of these wells.

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5.

In characterizing the extent.of groundwater contamination within the alluvial aquifer at the processing site, DOE has not considered possible contamination of the aquifer on the i

east side of tne San Miguel River, in as much as no wells or i

boreholes were installed over there.

DOE should l

characterire the groundwater quality in that area since wind i

blown contaminants have been identified on that side of the j

river.

6.

DOE's basis for meeting proposed concentration limits at the l

POC, at the disposal site, is the' isolation of the uppermost l

aquifer (i..e., the Salt Wash Member).

DOE has concluded j

l that this aquifer is isolated based upon 1) the large thickness of the confining units (i.e., the Brushy Basin j

Member) and 2) the low hydraulic conductivity of the confining unit.

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DOE has provided no definitive basis to conclude that the i

Brushy Basin Member has a low hydraulic conductivity.

DOE i

claims that the confining properties of the Brushy _ Basin Member is evidenced by the potentiometric surface rising 100 j

to 150 feet above the top of the Salt Wash Member. Howeverc this is only evident in two walls, both wells are located fairly close to each other; therefore, DOE has failed to i

show that this pressure gradient is consistent throughout the property. To further support their argument that the 1

Salt Wash Member aquifer is isolated, DOE should either provide information on the hydraulic properties of the i

Brushy Basin Member and/or install an additional deep well j

(at another location) to demonstrate that the pressure gradient is consistent throughout the area.

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7.

In characterizing the hydrogeologic system at the disposal i

site, DOE has concluded that the groundwater system in the Dakota / Burro Canyen (D/BC) is not the upper-most aquifer i

because it is a perched system of limited extent, with a permeability insufficient to deliver 150 gallons per day.

I While I agree that the permeability of the material is what one would expect from a aquitard and not an aquifer, permeability alone is insufficient to determine the expected yield to a well.

Further, only two of the wells drilled into the D/BC units were dry,'which may'only indicate that the groundwater system has a linear pattern.

Accordingly, l

DOE needs to provide more information to support their claim l

that this should not be considered the upper-most aquifer.

i This information could include well yields and/or drawdown data from observation wells.

j 8.

In describing the Salt Wash Member aquifer, at the f

processing site, DOE indicates that this aquifer is a major i

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, ths,other hand indicato thSt bascuco of.ita lon cenductivity it may not be capable of yielding an c-supply of water to a domestic well.

This contradiction 4.culs to clarified.

9.

DOE has indicated their intentions to use the background l

groundwater quality of the Salt Wash Member, at the process'ing site, as the background groundwater quality of the salt Wash Member at the disposal site.

No information has been provided.to support the conclusion.that the water quality at these two locations should be similar.

Further, at least one of the two wells (i.e., well 502) at the processing. site should not be considered an up-gradient well, since it is drilled within an area.that could be j

influenced by conthaination of the mill yard.

4 10.

In assessing drainage through the base of the pile, DOE used a hydraulic conductivity of lE-4 cm/s for the upper 60 feet of the Dakota Sandstone.

The lE-4 cm/s value was determined I

frc-taaker test results.

In-reviewing the geologic cross l

sectrins of the area, there are a number of isolated shale and claystone units within the upper Go test of the Dakota san: stone, some of these units appeat,to extend laterally's for a long distance.

I have serious reservations-that th permeability of these-units are anywhere close to 1E-4 cm/s.

DOE needs to provide adequate documentation to show tnat i

these units were adequately represented in their the zones l

that they ran their tests on.

Further, packer tests are suitable only for determining l

hydraulic conductivity in a lateral direction.

While this may be appropriate for sandstone units (if the zandstone units have fairly uniform characteristics), it is. totally l

inappropriate for a layered unit, such as.claystone or shale.

Therefore, DOE needs to either demonstrate that i

these units are of very limited extent throughout the area or run tests appropriate for-determining-thu vertical hydraulic conductivities of these units (laboratory tests of cores would be cppropriate).

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DOE should provide the basis for their selection of their surface water sampling locations.

Sample. location no. 533 appears to be located too far down-stream to provide any useful information.

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1 GIKHTDt(ICAL ENGINEERING RINIDi CD9EENTS 4

IRAFT RISEDIAL ACTICH PLAN URANItM MILL Th1 LINGS REMEDI5L' ACTION PR37BCT

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NATURITA, CDICRADO

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Reviewed by:

Banad Jagannath, Geotechrdoal Engineer, LLTB 4

1.

Secticn 1.2 Site and Pr-M Action; Runedial Action Selection Report,.

pay 5 The proposed rumedial action does not include rumcual of contaminated naterial from certain armas, and COE plans to request Supplemental Standards for these areas. The DOE shculd prtwide a detailed justification for requesting Supplemental Standards and not performing any runedial actions at ttwee areas.

2.

Section 3.3.1 Construction Methods and Features; Renedial Action Selection Report, Demolition, page 38 The report does not state dwther the demolition debri to be buried in the.

trendt beside the di&1 cell is contaminated or uncontaminated. The report should clearly state that any radiologically otutamirated debri will be disposed of in the d!& 1 onll.

3.

Geotechnical Design Parensters - Information for Bidders, Volume II, and Preliminary Design calculations, Volume II, calculations 17-737-01-00, sheet 3 through 7.

The draft RAP documents present data of WWeal field and laboratory irnestigations in the "Information for Bidders" volume ard the design details in thn " Calculations" volume. The "Informatica for Bidders" volume presents.

all the data collected without any interpretations and recommendations on the site darkcteristics and design parameters.

The design "QLloulations" volume presents the laboratory test data, tabulation of the paransters from the tests, 4

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re:xananded design parsestars, and supportirug design calculttions. However, the following information is missing in the " calculations" vohases : 1) profiias and cross sections to suport the mEnnad stratigraphy and to denonstrate the adequacy of the socpa of the WWeal investigations, 2) justification as to why the laboratory tasting perforned is adequate, 3)

. justification as to why the average values of test results of a few selected sanples are appropriata design paranaters. Section 3 of " Standard Format and i

Content for Documentation of Renedial Action Selection at Title I Uranium Mill Tailings Sites," February 24, 1989, presents the geotechnical information to be' provided in a Ratnadini Action Project humarrt. The final RAP documents should provide the mi.asing information identified above and justify the design parameters.

4.

Disposal Call Cover and Radon Barrier - Preliminary Design Calculations, Volume II, Calculations 17-741-02-00.

The sketches and drawings presented in the slope stability calculation sheets (for ex. sheet 15 of Redon Barrier Design calculations, page 61 of Renedial Action Selection Report) show a bentonita mat as a layer / element of the cover. But the Bid Specifications and Drawings h=nt do not include this as a work itdat. This inconsistancy is noted in other locations in this multi-voluma draft RAP documen*J; please rectify this.

The radon barrier thickness calculation assumes that the radon barrier layer is underlain by a minimum of 4.2 feet thick'or a 21-feet wide wedge of Windblown material (low-contaminated natarial) in the north and east slopew of the d4===1 cell anbankaant. However, this design requirunent is not carried throu$1 to the drawings and specificaticos. The drawings and 3pecifications should be revised to indicate the above requirement to ensure implementation of this design assumption.

The todon barrier design assumes that hitstaminated materials will be placed at the botteet of the di===1 can and low-contaminated materials i

i will be placed at the top or i W iately beneath the redon barrier layer.

The drawings wing the Bid Specifications do not indicata any ~

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3 requirusent cf selective plaomaant cf contaminated materials in the M &1 call. To ensure inplementation. of this design assumptions, the

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drawings should be zwised, at least by a nota, to indicate the above restirement.

The final design of the radan barrier el;4uld consider the above concerns and also p it a sensitivity analysis to demonstrate the conservatism in the design paramatare (particularly the long-term moisture content of the Win & lown material) and the design thickness of the raden barrier.

The design value of the coefficient of saturated hydraulic conductivity (2.2 x 10 -8 cms /sec.) for the raden barrier material is the average value of the parameter determined from laboratory tasts performed on a few selected sanples. The permeability tests have been conducted selectively on soil sanples whickt have a high %.t of passing No. 200 sieve size and significant clay contant, as indicated by the plasticity index of the material. BJt there are many sanples frtan the sane borrow area which do not have the above property. Prwide a justification as to why this selective testing and using the average laboratory test value as a design paramstar for field conditions is an Wale ard conservative approach.

Prwide a rational as to why a field hydraulic conductivity test is not recommended for this case, that too when the desired hydraulic conductivity is 2.2 x 10 -8 ass /sec..

The specifications for the radon barrier material should be ham on the properties of the soil samples tasted in the laboratory to establish the design phrtmeters. However, the specificatiens have no Plasticity Index requirinent for the clay material intanded for the raden barrier layer, and the present requirunant for the udninua Wwit passing No. 200 sieve is not a conservative representaticri of the material tested in the laborobuy (see page 02228-2 ard 02228-4 of Bid Specifict.tions and sheet 3 l

of Design Calculations, Volume II). The specifications should be zwised i

so that any soil satisfying this specificatics) would be expected to have properties similar to the soil sanples testad in the laboratory.

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Slope stability - Preliminary Design calculations, Voltans II, calculations 17-740-01-00.

e The critical czoes secticm of tL slope analyzed for stability shows the thickness of the frost probaction layer to be 2 feet, eereas the l

thicknees of this layer as per the drawirgs aooampanying the bid i

specificatigns is 3 feet. Corra::t thickness of this layer should be used in the slope stability evaluation that will be presented in the final RAP h unarits.

As irdicated in the calculations (sheets 1 and 6 of slope stability l

calculaticris), nost of the soil paranaters have been assumed ard their validity should be established (see cannants on gootedinical parameters).

In the absence of adequate testing to establish design parameters for all-L

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materials, sensitivity analyses should be performed to demonstrate the conservatism in the design resulting from the assumed values for the f

material parameters.

i In the calculations to be sutnitted with the final RAP documents, please

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include copies of the camputer print out of the stability analysis for the.

critical came showing - 1) the cross section analyzed, 2) soil stratigraphy ard parameters used, 3) critical failure ~ surface, 4) the minima factors of safety against slope failure for the conditions a

i analyzed.

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