ML20211K501
| ML20211K501 | |
| Person / Time | |
|---|---|
| Issue date: | 11/25/1986 |
| From: | Hawkins E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Martin D NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| REF-WM-54 NUDOCS 8612050037 | |
| Download: ML20211K501 (18) | |
Text
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fy pur UNITE 3 STATES 4
NUCLEAR REGULATORY COMMISSION m5' S
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WM DOCKET CONTR,gNIUM RECOVE CENTER FIELD OFFICE DENVER, COLORADO 90225 IS
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" tribution:
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l Docket No. WM-54 MEMORANDUM FOR:
Dan E. Martin
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7 Low-Level Waste & Uranium Recovery Projects Branch Division of Waste Management FROM:
Edward F. Hawkins, Chief Licensing Branch 1 Uranium Recovery Field Office, Region IV I
SUBJECT:
GRAND JUNCTION DRAFT REMEDIAL ACTION PLAN The attached connents on the Grand Junction Draft RAP were recently received from the Colorado Department of Health.
Since Grand Junction is the responsibility of WMLU, I am forwarding these comments for your use in continuing your review.
Sincerely, war awk s,
h ef Licensing Branch 1 Uranium Recovery Field Office Region IV
Attachment:
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COLORADO DEAARTM kJ 0
LTH Richard D. Lamm h
mas M.? rnon, M.D.
g Govemor 1876 MeU3ec:fJxe 'th Director 12 October 24, 1 52 e
4 Mr. John G. Themelis, Project Manager 00enTra Uranium Mill Tailings Remedial Action Project Office,k M
g U.S. Department of Energy OCT 2 91986 > jZ
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5301 Central Avenue, N.E. - Suite 1700
~j Albuquerque, N.M.
87115 gP 00cETctEng N
RE: Grand Junction Draf t RAP /SCD, dated June,1986 9
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Dear John:
We have reviewed the draft
- RAP, including the Processing Site Characterization (Appendix D),
and the Cheney Reservoir Disposal Site Characterization (Appendix E,
Volume II) for the Grand Junction mill tailings site, dated June, 1986.
Comments were sent to you in draf t form on October 17, 1986.
Also included in that package were comments submitted by the Colorado Department of Highways and the Colorado Geological Survey.
We note that the Draf t RAP does not incorporate previous State of Colorado y,
comments submitted to the Department f Energy on the Draft Environmental Impac t Statement.
Our comments on th Draft RAP are therefore intended to compliment those provided to you on the DEIS. We would like to request that Jon Luellen meet with you as necessary to further resolve specific comments on the DEIS an'd-the draft RAP.
At our upcoming meeting in Albuquerque we recommend that discussions focus on the following concerns which we consider 4
to be the most critical to the development of an effective remedial action
(
design for the Grand Junction site:
r 1.
The proposed tailings containment and cover system does not appear f
to be thick enough or durable enough to ensure long-term stability j
and perfomance Uncertainties in design parameters needed to be conservatively accounted for, and key assumptions in the radon barrier thickness calculation need to be further verified.
The estimated cost for constructing the cover / cap and erosion protection system needs to be evaluated in more detail, and possible cost l
saving measures further investigated.
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F Mr. John C. Themelis, Project Mana:;er Octobe r 24, 1986 Page 2 2.
Water quality at the processing site should not be further degraded as a result of excavation of the mill tailings and related contaminated materials.
Surface and ground water flow control methods and dewatering procedures should adequately, protect the local ground water regime and provide for year-round operations at the site.
The proposed wa ter-trea tment unit should be optimized during the decontamination effort so that the flow and dispersal of contaminated waters can be properly contained and controlled.
3.
Additional verification is needed of certain analytical results of ground water sampling at the site, including the determination of background water quality, and the existence and distribution of various hazardous and potentially toxic contaminants in the vicinity K
of the designated site.
Further discussion of appropriate aquifer protection / restoration goals should address the plumes of uranium, arsenic ammonium, and possibly of molybdenum, selenium and other contaminants, especially in the shallow ground water zone.
4.
As noted in our previous comments and in your cover letter to the Draft RAP transmittal, adverse impacts from fugitive dust emissions at the Grand Junction site, transportation corridors (e.g., unpaved roads), and the Cheney Reservoir site will need to be controlled.
Additionally, transportation noise impacts should be further 3
considered and specific noise abatement measures developed and applied as necessary.
If you have any questions regarding our review please call me or Jon Luellen at Extension 6246, respectively.
We look forward to discussing items E
related to the Grand Junction Draft RAP with you in the near future.
Sincerely, W-au7t-eau:r Paul Ferraro Program Manager, UMTRAP PF/ms cc: w/a ttachments :
Thomas looby, OHP 4Jk11awkins, NRC G.A. Franz, CDM/GJ H
F STATE O: CO10XA70 DEPARTMENT OF H4GHWAYS 4201 East Arkanees Ave.
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Denver. Co6oreco 80222
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p September 19, 1986 SEP 231986 Mr. Paul Ferraro Rx colorado Department of Health d
4210 East lith Avenue (QE Q[ HEALTH PROTECTION Denver' Colorado 80220
Dear Mr. Ferraro:
We have congleted our review of the Draf t Remedial Action Plan and Site conceptud Design for the Stabilization of Inactive Uranium Mill Tailings at Grand Junction and have the following coments.
We are resubmitting our original comments made on the Draft Environmental Impact Statement for Remedial Action at the Climax Uranium Mill Tailings Site to insure that you understand the areas of our concern and legal responsibilities regarding the mill tailings site in Grand Junction.
We note that the haul route for disposal of mill tailings has not been de-termined but that the originally proposed route has been abandoned.
The route is now confined to US 50 for the round trip haul.. We have no problem with that proposal provided that both the entrance and exit to US 50 are fully channelized and the haul (truck loads) on the State highway system is legal.
However, it should be remembered, as noted in our original 3
comments, that the Fifth Street bridge on US 50 is scheduled for replacement
.in Fiscal Year 1988-1989.
This construction will result in traffic delays on US 50.
Additionally, this change of access points on to and off of US 50 will require the processing of a Colorado Access Permit once final design and r
finalization of the haul route has been completed.
We will be reviewing the aspects of this project at that time.
Thank you for the opportunity to provide comments on this document and we look forward to reviewing future documents on this project.
Very truly yours, NM Barbara L. S. Chocol Manager Project Development Branch Attachment ew--
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DEPARTMENT OF HIGHWAYS o
4201 East Arkansas Ave.
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Denver. Cosoraoo 80222 f
(303) 757-9011
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May 20, 1986 Mr. Paul Ferraro office of Health Protection Colorado Department of Health 4210 East lith Avenue Denver, Colorado 80220 Dear Mr. Ferraro The Colorado Department of Highways has reviewed the Draf t Environmental 3
Site in Crand Junction. Impact Statement for Remedial Action on the Climax Uran haul and the selection of the haul route to the disposal area for theW fol3owing reasons.
The DEIS states that SH 146 (32 Road) is being improved.
to SH 146 (now designated SH 141) are complete and are located north of the -
The improvements designated haul road (D Road).
of,SH,141 between D Road south to US 50.We have no bnprovements planned for the seg The return trip of the haul road occurs on US 50, back into Grand Junction on~
33 Fifth Street.
bound Fif th Street Bridge over the Colorado River during Fisc which could affect the movement of a large number of trucks associated with the tallings removal process.
We offer this information as construction p.
will result in temporary traffic congestion.will require a two-lane, tw
- "tb The intersection of US 50 and the Cheney Reservoir Disposal Site road will require the Department of Energy to submit an access permit for this haul road access point.
intersection be fully channelized to include a lef t-turn lane and 'anA acceleration lane to meet current design standards.
has been included with this letter for your use when the project nearsA blank access pe the implementation / construction stages.
Because of potential traffic conflicts with the intersection of SH 141 and US 50, signals may have to be installed or flagmen used at this intersection during hours of extensive truck haul.
We also request that the costs associated with the repair of high or stabilization resulting from this repetitive truck haul activity be paid way surfaces 7
1 t.
Mr. Paul Ferraro May 20, 1986 Page 'No for by the Department of Energy.
or routine maintenance activities.These would be damages other than normal result in severe damage to the asphalt surface and subgrade stabiliz Usually, the slower the truck movement, the more extreme the damag on.
fore, we expect a problem on SH 141 heading south af ter crossing th e..
There-over the Co,lorado River.
e bridge As noted in the above comments, we have no serious concerns about th
/
but do have some responsibilities for the safety of th e project c and
' disposal area.
porated into the overall tailings removal project, our concern e
been satisfied and the safety of the traveling public will be insured e
If you have any questions concerning these coments, please call this 3
or Larry Abbott, District 3 Environmental Manager in Grand Junctionoffice We appreciate the opportunity to provide coments on this project
, 248-7223.
Very truly yours, Barbara L. S. Chocol Manager Project Development Branch P.
4 Attachment cc:
L. Abbott OF4--
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RICHARD D. LAMM OOVERNOR JOHN W. ROLD OsRECTOR
- 1876
- COLORADO GEOLOGICAL SURVEY DEPARTMENT OF NATURAL RESOURCES 715 STATE CENTENNIAL BUILDING - 1313 SHERMAN STREET DENVER, COLORADO 80203 PHONE (303) 866-2611 October 16, 1986 a.
Mr. Paul Ferraro Office of Health Protection Colorado Department of Health 4210 East lith Avenue p
Denver, CO 80220
Dear Mr. Ferraro:
The Colorado Geological Survey has reviewed the Draft Remedial Action Plan and Site Conceptual Design for Stabilization of the Inactive Uranium Mill Tailings at Grand Junction, Colorado.
Our primary concerns with the remedial action design presented are summarized as follows:
1.
The proposed disposal cell cover, as described in the June,1986 dRAP, has been substantially reduced in thickness over the cover J
described in the March,1986 DEIS.
It has also been shown that this reduced cover costs more than the thicker cover originally proposed.
The thinner cover will not satisfactorily prevent either the exhalation of radon gas, or the infiltration of water and the potential contamination of the shallow water table. CGS and others have commented many times on the importance of a properly engineered protective cover. These comments have, and will, continue to address deterioration due to the development of dessication caused tension cracks, stresses due to the action of corrosive salts, climactic variation, and plant and animal intrusion. All of these, and other factors, will have a more deleterious affect on the thinner cover l
than they would on a more substantial cover. This is made evident by i
a study of Casagrande crack propagation depths in this type of soil.
It is further recommended that infiltration studies be pursued in i
conjunction with CGS so that the future cover design will be fully optimized.
2.
The excavation of the radon barrier material and the excess spoil will expose sandy, cobbly pediment debris, and unstable, incompetent soils with high permeabilities. The beneficiation of this material, especially if water is involved, may not be cost effective.
It would be prudent to consider alternate borrow sources which might have more suitable material, even though this would require haulage and related Alternate borrow sites could be evaluated with respect to cost.
their alternative geochemical properties, and this made a borrow sito consideration.
GEOLOGY STORY OF THE PAST.. KEY TO THE FUTURE
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e Mr. Paul Ferraro October 16, 1986 Page 2 Our secondary concerns with the remedial action design presented are summarized as follows:
1.
Incision rates of existing and potential new channels or gullies in the project area are of concern to CGS.
Growth rates, as stated in W ppendix: E, for regional erosion may not be applicable to the Cheney A verification of the erosion rates should be considered, area.
especially since the Mancos Formation has such erodible characteristics and underlies the pile.
The pile must be protected from possible undercutting, rM it is our concern that the rock apron 31 may be insufficient to prevent deep and persistant gulley / channel erosion.
2.
Although this area is relatively stable reisraically, the maximum credible earthquake is listed as M=5.5 to 6.5. and a minimum acceleration design criterion is listed as 0.1 g.
Due to the nature of the material in the pile and the expected infiltration, an opportunity for increwed pore pressure and consequent reduction in effective stress my cause liquifaction during a seismic event.
Frost heave ars cliMuction may be ev.3cerbated in the pile with the predicted inffitratten through the tMr. cover.
3 Thank you for your review and consideration of thxe concern.
We look forward to the opportunity to discuss these points and otters and settle any differences before further planning is initiated.
p Sincerely,
%[
H Mark W. Davis, Chief Mineral Resources Geologist bcr: MWD-87-007 3261/3 da
Comnento en Crcnd Juncticu Draf t RAP /SCD, datsd Juna,1986
_Coassent No.
Page Section/ Paragraph Comment 1
8
- 2. 4 /4 Add "and the environment" to the end of the sentence that reads in part
"... monitoring, maintenance or emergency measures necessary to protect public health and safety [and the environment]..."
2 9
2.5/1 An additional secondary concern is for exposure to other contaminants associated with the tailings.
3 23 3.3.3/1 Because the design earthquake has a magnitude of 6.8 and occurs at a distance of only 5-6 miles, little M
attenuation may occur.
In this regard, it seems possible that the expected peak horizontal acceleration of 0.42g has been overly attenuated (Section B.4.2).
An earthquake of this magnitude, at this distance, may need to be considered rupturing for unconsolidated sediments and fill, and could lead to slumping, especially of fill on steeply sloping ground. Expected moisture levels within the embankment may also c' hance such n
failure modes.
4 25 3.2.4/5 According to Section E.5.1.3, no tests on soil erodibility were performed on samples obtained from the Cheney Reservoir " borrow site" area. Were x
other tests conducted in the general area tc determine soil dispersivities?
What is the basis of this statement?
5 34-37 3.5.1/A11 Please refer to earlier Colorado comments on the DEIS regarding characterization of ground water conditions at the processing site. See also comment #13.
6 39 3.6.2/1 The text does not include a discussion of present surface water use in the area of the Cheney Reservoir site (Kannah Creek, Indian Creek, Whiting's Ditch) or the potential for additional surface water development and use.
The DEIS concluded that, on a relative basis, the value of surface water resources in the area is moderate to high (DEIS, F-206).
~
Consent No.
P'at Sictirn/ Peregr:ph Cosmaent p-6 39 3.6. 2 /1 The repository design should more Continued adequately address infiltration, ground water recharge into the sub pile area, and seepage from the pile, and eventual i
contamination of downgradient ground and surface waters. See also comment #12.
i 7
42 4.2/3 Colorado has a number of concerns regarding the cover design proposed in the dRAP. Several key assumptions made l
in the radon barrier thickness computation may need to be
[
reconsidered. In addition, the proposed cover / cap system does not appear to be thick enough to provide reasonable assurance of long-term containment performance. We would like to discuss this issue with you further at our upcoming meeting.
8 47 4.3.5/4
'the irrigation ditch may need to be abandoned or redesigned to prevent erosion of surficial soils and to i
prevent seepage / recharge which could be causing an increase in ground water levels at the disposal site. Additional data is required on possible recharge relationships between the irrigation ditch and the shallow ground water
]
environment at the proposed disposal area.
9 49 4.3.7/3 The subgrade at the proposed disposal site has not been characterized in enough detail to ascertain attenuative geochemical properties. Discontinuous sones will have entirely different Physical and chemical properties.
In addition, confirmatory modelling would need to be performed of the potentially i
sitigative effects of this geochemical attenuation..The ion exchange process is strongly pH-dependant, as are sorption processes.
Precipitation will be limited if significant concentrations of certain in-situ aqueous species are available to form stable aqueous
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complexes with,
e.g., metal ions.
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Cosiment No.
Pag 7 S ctien/Parcgrcph Comment 10 50 4.3.7/3 The rock rip rap cover will act to increase infiltration by trapping runoff and melting snow.
The large negative pressures and strong capillary suctions within the clay cover matrix need to be considered when estimating percolation rates into the pile.
For example, much of the water may be " pulled" from the overlying bedding zone before it can drain off the pile laterally, 11 50 4.3.7/1 Shallow ground water in the vicinity of the Cheney Reservoir site is probably too poor in quality, in general, for domestic use, but may be useable in localized zones.
Significant quantities of deeper ground water may be available, but their potential is unknown.
P Considering that the potential for further development in this area is moderate to high, ground water contamination should be adequately addressed in the final design as a matter of prudent land use policy.
The State emphasizes that the disposal site should be designed to protect existing and potential future uses of water resources in the area of the site
)
and minimize degradation of such waters above their existing levels.
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Comment No.
Pag') Svetion/ Par 23reph Comment 12 50 4.3.7/2,3 Further discussion of aquifer protection /
51 4.3.7 /1 restoration strategies for the processing site should address the 4
plumes of arsenic, ammonium, uranium, and possibly of molybdenum, selenium, and other contaminants. The validity of analytical results of ground water sampling at the site, including determination of background water quality, and the existence and distribution of various hazardous and potentially toxic contaminants in the vicinity of the designated site needs to be be further verified. Please refer to more detailed comments provided an the DEIS. For example, the " statistically derived high" background value of 51 pC1/1 for uranium in groundwater appears to be much too high.
13 51 4.3.7/2 Certain of the monitoring wells should be preserved near the processing site so that contamination levels could be assessed some time into the future. We will review the well data and provide additional recommendations to you in the near future.
14 51 4.3.7/2; Last bullet: All significant unstable B-3 B.1.2/2 bottom materials, large stones, 3
incompressible soils, etc., should be removed from the bottom of the excavation prior to placement of the 24-inch low permeability layer. The 3
cost-effectiveness of producing this low permeability layer materials (and also the radon barrier material) from on-site excavated soils, gravels, and cobbles needs to be scrutinized. The costs of developing and implementing alternate borrow sources and various alternative cover systems should be investigated.
Please see additional comments of the Colorado Geological Survey.
15 52 4.3.8/1,2,3 The proposed design of the impoundment rock armoring protection may not adequately address possible undercutting of the disposal cell in the long term.
The pot antial for gully initiation I
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i Cosiment No.
Pas 1 Section/ Paragraph Comment
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15 52 4.3.8/1,2,3 and/or debris flow in the upland -
Continued watershed should not 'be discounted over 1000 years.
In addition, incision rates 3
in the Mancos Shale are variable and.
L, growth rates and rates of headward erosion for existing channels / gullies in the area have been estimated to be as high as hundreds of feet in 1000 years (E-40). The washes that surro'und the '
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site are occasionally incised to depths
/
of five feet or more and some show steep banks indicative of rapid erosion (DEIS, l'
E 2 -16).
L 16 55 4.3.9/1 Second bullet: This statement (regarding excavation of off pile
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contaminated materials) is inappropriate-and would appear to unduly represent the +
remedial action as being one of d
minimizing the decontamination effort.
S 17 55 4.3.9/1 Last bullet: See comment #16.
18 57 4.4.3/1,2 Please see the attached letter frba the 58 4.4.3/1,2 Colorado Department of Highways for general comments related to tailings transportation.
i 19 58 4.4.4/5 One (1) foot of freeboard in the retention basins will probably not be sufficient to prevent wave wash in a wind or over topping and seiche during a storm equal to or exceeding the 10-year 24-hour storm.
If the water generated from the remedial activities atithe site, in addition to precipitation resulting from this design storm, cannot be adequately contained on site without release to waters of the State, then '
State discharge provisions would be i
invoked and a permit would be required for any discharge of pollutants.
The
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retention basins should therefore be sized for complete containment.
Will these ponds be lined? Appropriate low permeability liners should be installed in these reservoirs to prevent or minimize further contamination of foundation soils and the shallow ground water system.
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- r Comment ho.
Pest Section/Parrarrph Comment h-h 20 59 4.4.5/1 The use of contaminant-laden ground water 4.4.6/2 for dust. suppression purposes does not appear to be environmentally appropriate or advisable (due to the proximity of J
the millaite to populated are.ss).
It is
'J
,'G recommended that such water be pumped to a sedimentation basin and treated prior to discharge.
's 21 59 4.4.5/2,3 As noted in our previous comments on the DEIS, the State has concern that further degradation of water quality and other adverse conditions created as a result of excavation activities at the Grand a
Junction site (processing site) should be adequately mitigated. A possible g',
means of controlling surface and ground water flows and minimizing additional E
contamination of the local ground water system would be to construct a slurry wall / clay-filled trench plus bers along a portion of the site perimeter, and I
install and activate an appropriate well-withdrawal system and water
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treatment facility.
22 64 Table 4.1;
'Ihe estimated cost for erosion B-3 B.l.2/2 protection appears to be excessive and should be further investi' gated.
Possible cost-saving alternatives should
)
be considered. Also, under the current proposal, if water is needed to wash the rock, prior to placement, where is it to be obtained?
5 23 69 6.2.6/1 It is stated on page 65 that the RAC will 70 6.2.6/1 prepare a site-specific Environmental, Health, and Safety Plan which meets the requirements of the UMTRA Project Environmental, Health, and Safety Plan (DOE, 1985). Is the statement here that l
~f the DOE will also prepare such a plan prior to the RAC in error?
24
' 77 9.2/3 Second sentence: Should state that
" Recorded oral comments and submitted written statements are being considered
}
by the DOE in preparing the EIS, and will be reflected in the final remedial action plan."
1
Comment No.
Pagt Stetien/Parrgr ph Comment 25 B-3 B.1.2/3 The assumption that sands and slines will become nearly " uniformly" mixed as a result of excavation and relocation
[
does not appear to be a reliable one.
26 B-3 B.1.2/5 Rubble from demolition activities such as large slabs of reinforced concrete or portions of brick walls will be difficult to properly compact around.
Provisions should be made to assure that demolition rubble will be reduced to manageable sizes and not be placed within approximately 10 feet of the low permeability layer. See also comment
- 27.
27 B-26 B.S.4/2; The proposed layering of the contaminated B-27 B.S.4/ Table B.S.3 materials does not adequately take into 7
account the varying degrees of radioactivity and sizes and types of materials (e.g., concrete blocks, slabs / chunks, bricks, tree roots) that are presently found in the repository area. The vicinity property material will continue to arrive over the next 4 or more years at a slow rate, and will have a similar composition. Efforts to minimize the potential for subsequent settlement will be compro~mised due to constraints on the ultimate compactibility of these proposed topmost layer materials and on inevitable volume changes and changes in the density within the layer over time. Such p
settlement could cause cracking of the cover and result in unacceptable releases of rndon.
28 B-32 B.6.3 It is stated that "It is recognized that under real conditions there will be areas in a stabilized pile which exceed the radon flux limit...".. Such a design philosophy and approach is not viewed as being sufficiently conservative.
Conceptual and final design plans should incorporate and utilize the best or reasonably available technology to assure long-term stability and Performance of the containment system.
Key variables, including the large variability of natural processes, need to be accounted for in a conservative manner.
i g.
Comment No.
Pagt Sectien/ Paragraph Comment 1
l 29 B-32 B.6.3/3 The long-term cover moisture content has been estimated to be 17.5 percent based on the testing of one sample of borrow site material (B-37). In-situ moisture tests, however, performed on thirteen near-surface samples of CL/CL-ML material at the disposal site yielded an average moisture content of approximately 10.1 percent (E-100).
Were these soils tests performed during different seasons of the year? Soil moisture conditions in such a climate and environment (semi-arid) can be expected to be complex and variable.
The majority of moisture fluctuations will probably occur in the upper less than or equal to 1 meter of the pile.
It therefore seems prudent to assume a
)
lower value for the long term moisture content of the radon barrier.
30 B-33 B.6.7/2 The long-term moisture content (s) of the layered contaminated materials beneath the cover appear to be underestimated.
Recent studies suggest that significant Portions of a precipitation event which penetrates deeper than a few inches may become recharge (Klute, 1978; Lewis and Stephens, 1985).
Infiltrating Precipitation (particularly from larger magnitude events) will displace downward the moisture already in the profile, leading to increased amounts of moisture in progressively lower zones of the pile, and ultimately, in the tailings.
f
. Wetting-front instability phenomena may also enhance rates and amounts of net I
downward movement of infiltrating sositure.
31 B-46 B.6.13/1 A standard error of the mean (SEM) of l
2.3 pCi/g will probably not accurately I
represent the variations of radium content in the contaminated materials.
The repository materials, for example, contain large, interspersed volumes of pure sandy tailings and slimes. The sensitivity analysis may therefore not l
adequately reflect variations in Ra-226 content to be expected in the proposed topmost layer.
h
Comment No.
Pag 2 Szction/Pe.regraph Comment 3
32 C-3 C.2/2-To be consistent with Section 3.2, we recommend that this paragraph be rewritten as follows: " Clean fill may not be required in some of the excavated areas. In those areas where backfill after excavation is not required, residual contamination should be removed to the 5 pCi/g standard.
33 C-5 C.3.2/2 Recommend deleting the last sentence of this paragraph.
34 C-6; C.3.3/1; The Bendix Radiological characterization C-7 C.3.5/2 report indicates that at least two areas in certain on-site buildings exhibit direct alpha measurements in excess of the NRC-recommended limit of 5000 dpm/100 cm2 for removable and p
non-removeable surface configuration.
In addition, several measurements yielded alpha activities which appear to be elevated above the levels specified in Section C.1.
The State recommends that such surface contamination which can be feasibly removed be removed prior to the final verification survey for the buildings.
35 C-6 c.3.4/1,2 Please refer to our comments on the
)
Durango preliminary Final RAP for general comments on final verification survey procedures.
36 C-6 C.3.4/2 Second sentence-Recommend adding to the g
end:
"...if approved in advance by the UMTRA Project Office and the implementing agencies 7 37 C-7 C.3.5/1 1st sentence is not clear. 3rd sentence - Recommend rephrasing as:
"A l
total gamma survey will be performed and documented in every room in the lowest habitable level of each building, and other rooms as necessary. During the survey, the survey meter should be kept as close to the floor and accessible wall surfaces as possible. Any significant changes in gamma radiation levels above background will be noted and adequately investigated." Sch l
sentence - We recommend that this sentence be deleted as shielding effects will need to be taken into account.
Comment No.
Pagt S2ctien/Parsgraph Comment 38 D-5 D.2.2/1-7 Excavation volumes are based entirely on Ra-226 concentrations (Th-230 analyses were performed additionally on former settling pond soils) only.
It should be emphasized that later soils testing and analyses may indicate the presence of unacceptable levels of other toxic or hazardous constituents which could dictate further soils removal.
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