ML20235L518
| ML20235L518 | |
| Person / Time | |
|---|---|
| Issue date: | 01/10/1989 |
| From: | Lohaus P NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Matthews M ENERGY, DEPT. OF |
| References | |
| REF-WM-39 NUDOCS 8902270555 | |
| Download: ML20235L518 (6) | |
Text
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'J/4N 10 79E9 i
Mark Matthews Acting Project Manager 4
Uranium Mill Tailings Project Office i
Department of Energy Albuquerque Operations Office P. O. Box 5400 Albuquerque, New Mexico 87115
Dear Mr. Matthews:
We have completed our review of your comments on our draft Technical Position on Standard Format and Content for Documentation of Remedial Action Selection at Title I Uranium Mill Tailings Sites (SF&C). As you are aware, we have already responded by letter. dated December 7,1988, to certain general issues raised by your comment transmittal, and have discussed these issues further.
with you during our meeting of December 15, 1988. During the December.15th meeting, we also briefly discussed our responses to each of the detailed comments.
The enclosed response provides a more detailed explanation of our intentions relative to finalizing the SF&C in light of your comments. A copy of your comments is also enclosed to make it easier to follow our responses. Our present schedule calls for issuing the final SF&C in February,1989.
If you have any questions regarding these responses, please call Dan Gillen of my staff at FTS 492-0517.
Sincerely, m'.,.._.. iD BY Paul Lohaus, Chief Operations Branch Division of Low-Level Waste Management and Decommissioning, HMSS
Enclosures:
As stated Distribution: WM-39
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4 Response to DOE Comments on Draft Technical Position on the Standard Format and Content for Documentation of Remedial Action Selection at Title I Uranium Mill Tailings Sites Response to General Comments The introduction to the SF&C will be revised to make it clearer that:
'1)
The SF&C is not intended to require information beyond that which already has been made evident in previous NRC staff reviews and documentation (Standard Review Plan and staff technical positions).
However, since the SF&C is meant to cover all design conditions, some information listed may not be applicable 'to or appropriate for all sites.
2)
In addressing a particular aspect of the remedial action, the DOE document can summarize the pertinent information and reference the source (e.g., the TAD). However, the summary must clearly present the information and basis for conclusions relative to meeting the EPA standards.
Response to Recommendations on Section 2.0, Geologic Stability Recommendation 1:
In general, we agree with the proposed reorganization of Section 2.0 of the SF&C. Although the Section 2.0 table of contents will not be identical to that recommended by DOE, we agree that separating regional characteristics, site characteristics, and geologic stability analyses will result in a clearer and more logical document. Also note that subheadings under the information areas addressed in the SF&C can be added as DOE sees appropriate.
Recommendation 2:
The introduction to the SF&C will make it clear that since the SF&C is meant to cover all conditions, some information listed may not be applicable to or appropriate for all sites.
Response to Comments on Section 3.0, Geotechnical Stability Comment 1:
The Remedial Action Plan (RAP) report should be a stand-alone document presenting the proposed remedial action. The information contained should be i
detailed enough for a reader to understand the proposal without referring to
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DG/ MARK MATTHEWS
-2 Other volumes. However, details such as information gathered and analyses performed etc. could be presented in an appendix to the main report. Any reference, in the main report to the information presented in an appendix (or other reference), should be explicit and detailed enough to direct the reviewer to the exact location in the supplementary report.
Comment 2:
The " streamlining" process is not synonymous with reducing the volume of thc text or details of the information to be provided to the NRC. The RAP documentation must contain sufficient information for the staff to evaluate and make a finding on the proposed remedial action. The methods of analyses may be identified in the in the main report, and a further description of the methods and details of the analyses may be presented in an appendix to the report or in supporting documents.
If a detailed description of the method of analysis is presented in a reference document already submitted to the NRC (such as TAC's Technical Approach Document, MKE's VMTRA Design Procedures etc.), then an explicit reference to that in liet of a detailed description will be acceptable to the NRC. When there is a deviation from the standard method of analysis or a new method is used, then the DOE should provide a detailed description of the method of analysis in the main RAP report, either in the body of the report or in an appendix.
Comment 3:
The NRC staff agrees that if a commercially available and commonly accepted computer code is used, the validation and detailed description of the code need not be presented in the report. However, if in-house developed versions of commercially available codes, which are not available to the general public are used, then they should be validated and documented.
If such validations are presented in a document already submitted to the HRC, then they should be explicitly referenced.
A related item is in DOE's mark-up of Section 3.0 in which the request for manual checks of computer calculations is deleted. We would like to point out that the MKE UMTRA Design Procedures require that a manual check of the computer calculation,be performed (see Section 10.3.B, page 10-5 and Section 10.3.C, page 10-6), and that copies of such verification be included in the design calculations prepared by MKE.
Comment 4:
A brief discussion on the cover materials should be provided in the main report, and detailed information on cover materials' physical and engineering properties may be presented by an explicit reference to an appendix document l
submitted with the Remedial Action Plan report.
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- Comment 5:
The SF&C is not an appropriate vehicle to describe acceptable procedures for design.
However, prior to taking a generic position on this item, we would like to review the DOE's new approach to the design of covers against infiltration, the methodology used in evaluating the frost depth at a site, and design of a cover against freeze-thaw degradation.
Comment 6:
The entire construction specifications may be presented in a separate volume and may be appropriately referenced in Section 3.3.1.
However, the referencing should be explicit and detailed to indicate the section and page numbers etc.
Response to Comments on Section 4.0, Surface Water Hydrology and Erosion Protection Comment 1:
It was intended that previously presented information needed to address another aspect of the remedial action could be explicitly cross-referenced rather than be repeated. Rather than state this in each introductory paragraph, we will make it clear in the SF&C introduction.
Comment 2:
Specific reference to procedures or methods addressed in the TAD or other documents that have been provided to the NRC staff is acceptable.
Response to Comments on Section 5.0, Water Resources Protection Comment 1:
DOE asserts that thete are no reasonable failure scenarios for the disposal unit, and that potential failure events have been accounted fcr in design and construction. DOE also states that the cover meets design and construction specifications, and that infiltration is the only potential failure scenario that needs to be considered in the corrective action plan.
The usefulness of a failure scenario analysis in designing the disposal unit and developing a monitoring and corrective action plan is to:
- 1) demonstrate that the disposal unit has been designed to minimize the likelihood and consequence of failure; 2) develop an effective monitoring network capable of detecting aberrant performance e.g., increased infiltration through the cover and elevated contaminant concentrations downgradient if failure should occur; and 3) demonstrate that aberrant performance can be readily corrected if it occurs.
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- NRC agrees that through standard engineering design analyses, DOE can demonstrate that the disposal unit has been designed to minimize the likelihood and consequence of potential failures. However, for DOE to demonstrate mitigation of potential failures, design and implement an effective monitoring program, and to demonstrate effectiveness of alternative corrective actions, DOE needs to consider unlikely, but conceivable scenarios that could lead to aberrant performance.
Although DOE plans to perform some sort of standard cover monitoring, depending on the mode and degree of failure, infiltration may occur through the cover along preferential pathways, thereby eluding detection by cover i
monitoring installations. DOE should therefore propose an integrated,.
site-specific groundwater monitoring network, the design for which is based on reasonable failure scenarios, capable of demonstrating that initial performance of the disposal unit complies with the groundwater protection and closure l
performance standards under 40 CFR Parts 192.02(a)(3) and (4).
Comment 2:
DOE states that they plan to propose a cleanup standard for sites under a later task of the UMTRA Project due to the extensive site characterization necessary to evaluate aquifer restoration.
NRC has agreed that aquifer restoration can be deferred if DOE can demonstrate that the disposal activities will not preclude or preempt cleanup activities.
Because there are no plans to develop a SF&C specific to aquifer restoration, NRC consid-
,his section of the SF&C to be necessary regardless of whether DOE addrest - ;1eanup now or later.
In addition, DOE should find the information -Juired for groundwater restoration in this section useful in developing their rationale for postponing cleanup.
Further, consolidated site characterization programs for both the disposal and cleanup activities may be more productive, require less time, and be more cost effective than separate programs.
Response to Comments on Section 6.0 - Radon Attenuation and Site Clean-up Comment 1:
Supporting information detailing these test methods, their precision and accuracy, and their applicability for representing the long-term attenuating capability of the radon barrier materials need not be repeated in the RAP j
documents if they are already referenced in the NRC Standard Review Plan, and have been used in other projects to date. However, if any other new methods are used, then their description should be presented in the RAP report.
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. l Comment 2:
In order to reach conclusions relative to the EPA standard for raden release, i
the NRC staff requires a complete documentation of all aspects of radon barrier design.
This goal was not abandoned in the streamlining process. The information required should be presented ir, sufficient detail to enable the NRC to understand the approach being taken.
Further details may be presented elsewhere such as in an appendix if the location of the additional information is clearly identified in the text of the RAP.
In the past, most of the information required was presented in the appendix volume containing the radon barrier design.
All the information described in the SF&C is needed for the DOE's design of the radon barrier, and therefore, the DOE's contractors have to document all that in their design calculation volume. The design calculations are covered by the UMTRA Project QA requirements and should already be in a form suitable for submission to the NRC.
Therefore, furnishing the required material should not result in any excessive additional' costs.
Comment 3:
We will revise the wording to state, "... appropriate analyses that demonstrate that the design thickness of the radon barrier will meet the EPA standard for radon release...". However, determination of the minimum thickness required to satisfy the EPA standard would be a useful indication of the margin of conservatism in the design.
Comment 4:
Since the radon barrier is also an infiltration barrier, it serves dual functions. The significance of its thickness and possibly built-in conservatism in the context of satisfying its dual functions should be discussed in the RAP.
If this discussion is already provided elsewhere in the documentation, then a cross reference would be appropriate.
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Comment 5:
The SF&C will be revised to include characterization of the background concentration of Ra-226.
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Department of Energy.
Albuquerque Operations Office P.O. Box 5400 Albuquerque, New Mexico 87115 '
90f 2 9 WIS FEDERAI, EXPRESS a
Mr. Paul H. Ichaus 1
Director, Division of IwInvel Maste Management & Dam-issioning U.S. Itaclear Regulatory Consnission
.1 White Flint North '
11555 Rockville Pike:
Rockville, MD 20852
Dear Paul,
The Department of Energy (DOE) has conpleted its review of the Nuc" lear Regulatory Con 1 mission (NIC) draft 2%chnical Position on the Standard Format and Content for Documentation of Remedial Action Selection at Title I Uranium Mill Tailings Sites (SF&C) which was provided to us on October 20, 1988. Enclosed for your information are our specific coniments.
In general, DOE believes'that the SF&C contains some statements which may be construed to require different technical approaches than those currently used on the UNTRA Project. The DOE Technical Approach Document (TAD) establishes the agreed upon basis for design approaches and should take precedence over the SF&C.
'Ihe SF&C is vague on the level of supporting data to be submitted with DOE's remedial action selection report. Additionally, the SF&C could be interpreted to mandate a long, detailed, and conplex remedial action selection report. Prior to implementation of the SPEC, DOE and NRC nust agree on the scope of the r==61 action selection report and on the '
level of supporting data. We suggest that the entire submittal siculd consist of a brief (50-100 page) remedial action selection report and appendices consisting of the following: design specifications, drawings, and suip.ai.ing calculations; a site characterization report like the one currently submitted as Appendix D to UMTRA Remedial Action Plans (RAP);
.and a detailed groundwater document which provides detailed characterization information and DOE's conpliance strategy. Sections of DOE's current RAPS which would be deleted entirely are as follows:
Section 5.0, Environment, Health and Safety; Section 6.0, Responsibilities of Project Participants; Section 7.0, Surveillance and Maintenance; Section 8.0, Quality Assurance; Section 9.0, Public Information and Public Participation; Appendix A, Regulatory Conpliance; Appendix B, Engineering Design; and Appendix C, Radiological Support Plan.
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- We will be prepared to discuss our coments on the SFGC and our rex--;&tions shown in the previous paragraph during the DOE /NRC streamlining meeting on Daran**r 14 & 15, 1988. Should you have any l-questions regarding this transmittal prior to that meeting, please contact l
Debbie Mann at FTS 846-1243.
Sincerely,
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i W. John Arthur, III Project Manager Uranium Mill Tailings Project Office Enclosure cc w/ enclosure:
i J.E. Baublitz, NE-22 D.P. Dubois, JEG S.A. Mann, NE-22 J.G. Oldham, MK-F R.H. Richey, EMIRA M.R. Knapp, NRC-HQ E.F. Hawkins, NRC-URFO e
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~ DCE Constants on NRC Draft Technical Position'on the Standard Format and Content for Doctanentation
.of Remedial Action Selection'at Title I Uranium Mill Tailings Sites
- Section 2.0, Geologic Stability RBOCWENDATICN 1 o
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.b1 Table of Contents should be as shown below.
- 2.0 Geology 2.1. Introduction, sex)pe and previous studies 2.2 Geologic setting 2.2.1
-Regional stratigraphy 2.2.2 Regional physiography and geomorphology 2.2.3 Regional structural setting
. ;i/ r 2.2.4 Seismicity 2.2.5 Resources development activities 2.3-Site Geology 2.3.1 Geomorphology 2.3.2 Uricesolidated deposits 2.3.3 Bedrock stratigraphy and structure 2.4 -Geologic Stability 2.4.1 Geomorphic stability 2.4.2 Seismotectonic stability 2.4.3 Other hazards (bedrock concerns, seeps, fractures, paleochannels, etc.)
2.5 Sunmary of Geologie Stability Reasons for Recs..mdation:
o Site geology should be given a separate major heading instead of having site specific information dispersed under several headings.
The pr W format would require numerous crcss references to describe the relationship such as soil and bedrock to geomorphic processes.
o those topics which nust be addressed should be given a subheading so they can be located such as previous studies, fluid or mineral extractions (resource development activities).
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, IUIOl9ENDATION 2 S
It should be made clear that the proposed SF&C does not supercede'the o
Technical Approach Document (TAD). The SF&C content reads in some sections as if all possible factors must be addressed whether relevant or not. Content statements should be revised to read "The information should include such discussion as is pertinent, relevant, or appropriate."
Note: A marked up copy of Section 2.0 is provided as Attachment 1 to these comnents. The markup shows DOE's suggested revision of the SF&C to incorporate Recommendations 1 & 2 above.
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. Section-3.0, Geotechnical' Stability L
Comment 1:
The sumary tables and plots, described in section 3.1.2, that present the inportant test results should be included in a referenced attachment. Further clarification of the amount of detail required is. needed.. For exanple, would this attachment
'be similar to the Appendix D used in the present RAP format?.
Comment 2:
.In sections 3.2.1, 3.2.2, and 3.2.3 a request is made for a description of all methods of_ analysis. Conpliance with this request would lead to an_ increased volume of text rather than a streamlined text.
It is also redundant to include these descriptions when they have already been presented in.the Technical Approach Document (TAD) and the Albuquerque Operations Manual (ACM). hhere unusual conditions or deviations from these standard practices have occurred, the method should be appropriately referenced and included elsewhere in the remedial action documentation.
Coment 3:
The validation and description of conputer codes should not be included in the text as requested in sections 3.2.1(d) and 3.2.2(d). Comercial codes should not require any, validation and developed codes, if not h==nted in the TAD or ACM, should -
be appropriately referenced and documented in the additional =
remedial action documentation.
Coment 4:
The information to be provided_in section 3.2.4 includes a detailed description of the cover materials' physical properties and engineering parameters. This information should be included in the same referenced attachment that contains the sumary tables and plots for section 3.1.2.
Comment 5:
In the first paragraph of section 3.2.4, the determination of the cover materials' resistance to freeze-thaw degradation is-required. Clarification is needed to determine if the use of index test values and published enpirical correlations would be sufficient, or if specialized consolidameter freezing sets as performed by the U.S. Army's Cold Regions Research and Engineering Laboratory are required.
Cb ment 6:
Construction specifications that deal only with aspects of the remedial' action are requested in section 3.3.1.
Instead of preparing two sets of specifications, the specifications which are prepared for the bidders should be attached and referenced.
Cbument 7:
A marked up oopy of Section 3.0 is provided as Attachment 2 to these comments. 'Ihe markup shows DOE's suggested revision of Section 3.0 of the SFEC.
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4 g ion 4.0,-Surface Water Hydrology and Erosion Protection l:
1 Comment 1:'
The following sentence'should be. included in the first paragraph of sections 4.1, 4.2, 4.3, 4.4,'and 4.5:
"If any of the information is presented elsewhere in the remedial action d~'w=ntation, such information need not be repeated here but should be explicitly cross-referenced." The reduction of the amount of data, tables, plots, maps, and other details will keep the text streamlined.
l Comment 2:
In sections 4.5 and 4.6 a request is made for a description of the approaches used for testing and analyzing the quality of rock erosion protection. An explanation of the oversizing-method is also required. These methods and procedures are du'v=nted in the Technical' Approach Document (TAD),:and therefore should not have to be reexamined in this text.
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' ection 5.0, feater Resources Protection -
S Ccnunent 1:.
5.3.4 Groundwater Monitoring and Corrective Action Plan There are no' reasonable failure' scenarios.for the disposal unit.. They have been accounted for in' design and construction.
Cover nonitoring is proposed to determine whether infiltration through the cover meets design and con truction specifications to assure conpliance with the proposed EPA standards. Such infiltration is the only potential " failure. scenario".that should be addressed with a corrective action plan.
5.4 Groundwater cleanup The present-level'of site characterization is sufficient only to address whether the remedial action will.conply.with the proposed EPA groundwater standards.. Tne IXE has decided that aquifer restoration (groundwater cleanup) will be addressed under the next task of the IJMTRA Project and be part of a separate NEPA process because of extant characterization needs.
Groundwater cleanup requires extensive geochemical i
characterization of residual wastes and a more intensive investigation of unsaturated flow and aquifer properties. A cw w yi.ual strategy must be developed, modeled, and/or tested on a benchmark scale. Realistic. concentration limits and a cleanup standard can be proposed after this has been performed. There
- is presently no basis for any decision corcerning groundwater cleanup.
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. Section 6.0, Radon Attenuation and Site Cleanup Comment 1:
'Ihe SF&C requires'" supporting information describing the tes.
method, its precision.and accuracy, and its applicability for representing the long-term attenuating capability of the radon barrier materials." These are the same tests that are described in the Technica) Approach Document ard the NRC Standard Review Document. These have also been used for several sites' PAPS.
We do not feel that these tests need to be substantiated at this point in the Project.
Coment 2:
The DOE and the NRC clearly want a concise document that streamlines the review process; however, the requirements for the radon barrier design seem to be contradictory to this goal.
Specifically, a thorough description of the radon barrier design is required, along with the appropriate geotechnical and radiological information. Sumary tables and plots for the important test results, diagrams of modeled sections through the disposal cell, and so on are required. Presenting this level of information within the remedial action selection report would prevent it from being concise; on the other. hand, presenting this level in a supporting document would involve creating a new document, with the associated costs and time requirements.
'Ib present the information in a calculation would involve radical changes for DOE's contractors in the preparation of the calculation, along with associated costs and time requirements.
This contradiction needs to be resolved prior to implementation of the proposed SF&C.
Coment 3:
It should not be necessary to estimate the radon flux corresponding to the minimum design thickness (as stated in the SF&C) provided it is shown that the thickress is equal to or greater than that required to limit the flux to meet EPA standards.
Coment 4:
The requirement for, "a discussion of the physical significance (of the radon barrier thickness) in the context of the overall cover," (Subsection 6.1.2), cannot be provided without additional clarification.
Coment 5:
The radiological characteristics of the processing site should include background concentratLa of Ra-226, as the EPA limit is "above background".
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~2 GEOLOGIC STABILITY 3,1 Inh oducMon hoo c anct Previene 6kd.
es DDE should provide all the geologic, geomorphic, and seismic information utilized to determine that the remedial action meets the EPA standard.
The basic criterion pertinent to geologic stability is provided in EPA's 40 CFR Part 192, Subpart A (Ref.1).
40 CFR Part 192.02 states that control of tailings shall be designed to be effective for u? to one thousand years, to the extent reasonably achievable, and in any case, for at least 200 years. The EPA requirements and the implementation guidelines of 40 CFR Part 192 (Subparts A and C
and Supplementary Information sections) necessitate that due j
consideration be given to geologic, seismologic and geotechnical parameters.
.2.
2.y & Geo% sic. 6s %9 DOE should provide the geologic characteristics of the site and the region around the site.
The information should include geologic illustrations, data, and analyses that demonstrate that the geologic and tectonic processes affecting the site do not jeopardize its ability to comply with the EPA standard.
These processes should include the effects of fault displacement, uplif t, collapse, subsidence, tilting, and volcanic and seismic activity.
The basic geologic information required to provide a basis for evaluation is discussed below.
A literature search should be made by DOE for geologic studies of the site by government agencies, academic in7titutions, or commercial companies; and any published reports, maps, or other geologic information on the site should be referenced.
Information such as geologic or geophysical surveys, borings, excavations, or remote-sensing studies shou d be documented.
DOE's investigators should be identified, the investigatory techniques should be described, and any field or laboratory data should be included in the docur,entation.
Any nearby activities th6t could affect the site, such as subsurfice addition or withdrawl of fluids or mineral extractions, should be described and evaluated.
Maps showing the location and depths of these activities should be included.
2.1.1 Stratigraphic Setting
.ike. repon DOE should characterize the n;S:M ::d ;".;4peif t; stratigraphy to a scope and level of detail sufficient to demonstrate an understanding of the stratigraphy commensurate with providing reasonable assurance that compliance with 40 CFR Part 192 will not be jeopardized.
Regional Stratigraphy Regional stratigraphic information should be discussed in sufficient detail to give clear perspective and orientation to the site-specific information presented.
This regional information may be obtained from published reports, maps, private communications or other sources.
The discussion of the regional stratigraphy should be adequately referenced, and illustrated by regional
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3 surface and subsurface geologic maps, stratigraphic columns, and cross sections.
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P Site-Specific Stratigraphy ctescrie ens, ech 25 w
Informatio on the site stratigraphy "
ould incluoe discussions of the formation composition, sequence and corre ation of the lithologic strata under-m a9 i
the sit an gc r c;;, particle size, pr sence of organic materials, degree.of egg surrounding th site.
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N-include the
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cementation, zones of alteretion, and depositional environment of i
(} y 9 unconsolidated strata.
Stratigraphic columns and cross-sections illustrating A
the strata at the remedial action site along with the surrounding units should 9
accompany and be noted on a geologic map.
grsopach maps of near-surface f( A stratigraphic units, the bedrock surface, an other units related to the remedial action site sheeM be provided.
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Information gained from eld investigation, exploration, and sampling programs to define the strati aphy and properties of the surface and subsurface materials at the site, he uranium mill tailings as they exist at the site, and any borrow meterials planned for the remedial action design should be presented jietai Reference to information provided in accordance with Section 3.1 is pW acceptable.
The relationship of the site stratigraphy to the regional
\\ stratigraphy should be discussed.dk/ and e.viron%h) ceadionWp.
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Geomorphic Setting
,2,25 DOE should characterize the regional and site-specific geomorphology to a scope and level of detail sufficient to demonstrate an understanding of the j
geomorphic processes commensurate with providing reasonable assurance that compliance with 40 CFR Part 192 will not be jeopardized, er DOE should describe the regio 2 Tand site-spectric geomorphol of the disposal site. DOE should also describe the geomorphic processes af cting the present-day topography of the disposal site and vicinity.
Information should
- 'di include descriptions of processes such as mass wasting, eror. ion, slumping, lancs11 ding, subsidence, stream encroachment, and weathering where appropriate.
The discussion of relevant geomorphic processes should include their rates, frequencies of occurrence, and controlling mechanisms or factors.
DOE should describe the geomorphic investigations conducted to systematically analyze the regional and local landforms in order to provide evidence of geomorphic processes.
The physiographic (geomorphic) province (s) in which the site is located should be identified.
The extent and distinguishing characteristics (e.g., elevation, relief) of the province should be described.
l This description should provide the nature and extent of the major active processes mocifying the present-day topography of the province (s) and should be supplemented by pertinent large and small scale topographic maps (e.g., USGS 7.5-minute and 2-degree quadrangle maps).
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. DOE should include topographic maps, andTwhere approcriatei aerial photographs, thatemphasizegeomorphicfeaturespertinenttotiedisposalsiteandvicinity.
Topographic base maps of adequate scale should be utilized to generate geomorphic-hazards maps that delineate areas where landscape changes associated with drainage networks, slopes, rivers and piedmonts may adversely affect site stability.
Areas that may be subjected to subsidence due to natural or man-made subsurface conditions and areas where wind erosion may be a significant factor should be identified. Delineation of such areas should take into account the various factors influencing geomorphic processes such as relief, landform morphology, near-surface geology-pedology, and resident biota.
Each relevant geomorphic process identified should be described, including rate of activity, frequency of occurence, and specific controlling mechanisms or factors.
As necessary input into the geomorphic hazard evaluations, DOE.should assess the natural resources exploitation history and/or potential of the site. This assessment should consider, for example, the potential for mining-related surface subsidence at a site where underground mining is known to have occurred (based on mine development records), or can be expected to occur (based on inferences from available geologic information). This investigation should be based on pre-existing historical, geologic, and economic resources information.
0.1.0. Structural Setting y w e s e sec % y 2.2. 4
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DOE should characterize the regional 6d' local geologic structures to a scope and level of dett.11 sufficient to demonstrate an understanding of the structural geology commensurate with providing reasonable assurance that compliance with 10 CFR Part 192 will not be jeopardized.
The structural geology of the region should be described, and its relationship to the site geologic structures should be discussed.
Any faults, folds, open jointing, fractures, and shear zones in the region must be identified, and their significance to the facility should be discussed.
DOE should describe the location, attitude and geometry of all known or inferred faults, whether buried or exposed at the surface, at or in the vicinity of the disposal site. Those faults that can be reasonably expected to affect remedial action should receive special attention.
DOE shoulo discuss the relationship of these faults to the present-day local e Tss field. Fault displacements should be ide.itified and potential r m ience intervals addressed. DOE should also identify any potential effects on the disposal site as a result of deformation during fault displacement.
g,,., 4 %t DOE should discuss the nature and rate of deformation su h as folding within the disposal site and relate these to the local stress re ime.p Any joint sets within the disposal site including their densities and ientdtions should be described, and their relative ages should be discussed. femi ieralization and mineralization history of the various jointSolution cavities and crevices 1n the bedroc sets P o be discussed.
describ ed and discussed 9
if applicable.
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- 2. 2. 6 3rkt-Seismicity
.ok DOE should characterize the regional d : M: ;;xi; seismology and tectonics 4
to a scope and level of detail sufficient to demonstrate an understanding of these processes commensurate with providing reasonable assurance that compliance with 40 CFR 192 will not be jeopardized. DOE should provide information on regional and site-specific tectonics, earthquake history, correlation of earthquake activity with geologic structures and tectonic r.rovinces, and maximum earthquake potential.
Seismicity DGE should provide a complete list of all recorded historical earthquakes within an area affecting the site.
The listing should include all available information about the earthquakes such as epicenter coordinates, depth of focus, origin time, intensity, and magnitude, augmented by a map showing the locations of these earthquakes.
The references from which the information was obtained should be indicated.
In addition,)any earthquake that induced geologic hazard (e.g., landsliding or liquefaction should be identified, and the acceleration that caused the hazard should be provided. '
Tectonics oite DOE should identify all the regional ame 4eee4-geologic structures and tectonic n
activity that may contribute to earthquake generation or affect the suitability of the site for remedial action.
A map of all tectonic provinces should be provided.
The criteria used to delineate the tectonic provinces should be-A discussed.
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regional scale map showing the location of faults, their characteristics, P:
uld be pre g # % cce acn do be detec mined pcevio a
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.3d Geologic Stability okdice y spe<& c sechey 1A rs e m & rn w earnak e t
DOE should use the geologic conditions and processess characterized in Section i
M-($p in order to demonstrate that the proposed remedial action meets 40 CFR Part 192.02(a).
DOE should evaluate the site lithologic, stratigraphic and 13 structural conditions for their suitability as a disposal cell foundation and their potential for interaction with tallings leachate and ground water.
Geomorphic processes should be evaluated for their potential impact upon long-term tailings stabilization and isolation.
DOE should evaluate potential seismotectonic hazards, including seismic shaking, liquefaction, on-site fault j
rupture, ground collapse, and volcanism for the purpose of assuring that the j
long-term stability of the disposal cell and success of the remedial action design ein be achieved.
Furthermore, DOE should address any other geologic l
process that would impact the stability of the site.
2).1 Bedrock suitablity NW' DOE should present their evaluation of the s tability of the surficial deposits and bedrock units beneath the tailing pile and proposed disposal site.
This discussion should also include the interaction of the surficial deposits and bedrock units with the tailings leachate and ground water. DOE's demonstration should lead logically from the data and premises given to the conclusions reached, thereby providing a clearly defined justification for their conclusions.
Where mitigative measure are proposed, DOE should clearly
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7 define these measures and provide clear and logical justification in support of these measures.
2.f.2 Geomorphic Stability J
4 DOE should present their evaluation of the geomorphic processes and their I
potential impact upon long-term tailings stability and isolation.
This discussion should lead logically from the data and premises given to the conclusions reached, thereby providing a clearly defined justification for DOE's conclusions.
Where mitigative measures are proposed, DOE should clearly define these measures and provide clear and logical justification of these
]
measures.
J 1
2.f.3 Seismotectonic Stability 4
DOE should evaluate potential seismotectonic hazards and their impact on the long-term stability of the disposal cell and success of the remedial actf an design. This discussion should lead logically from the data and premises given to the conclusions reached, thereby providing a clearly defined justification for DOE's conclusions.
Reference to evaluations provided in accordance with Section 3.2 is acceptable.
Where mitigative measures are proposed, DOE should clearly define these measures and provide clear and logical justification of these measures.
2AA 2,fF', Summary _
DOE should summarize the results of their evalution regarding geologic stability of the remedial action and their conclusions regarding the ability of the remedial action to meet the EPA standard in the context of geologic impacts to the remecial action plan.
MTAce MEMT 2
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i 8
3 GEOTECHNICAL STABILITY The proposed remedial action must meet the EPA standard that control of the
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tailings be effective for 1000 years to the extent reasonably achievable and, in any case, for at least 200 years. For DOE to demonstrate this, the remedial action documentation must, in part, contain geotechnical information and design l
details related to the disposal site and all materials associated with the j
remedial action design including foundation and excavation materials, contaminated materials, and cover materials.
3.1 Site and Materjal Characterization Information shoulc, be presented that thoroughly defines the conditions and engineering properties of all soil and rock materials that are within underlying depths that could affect the performance of the proposed disposal cell, or that will be incorporated into the disposal cell.
Information on the geotechnical characteristics of a site and materials should include (1) the scope and results of geologic eotechnical endungsspapelena. investigations conducted at the processing site, the disposal site, and/or the borrow areas, (2) the scope and results of field and laboratory tests conducted to determine the engineerin properties of the subsurface, contaminated, and/or borrow materials, (3) gthe groundwater conditions at the disposal site as they relate to the geotechnical design, and (4) interpretation of the disposal site stratigraphy.
If any of the information relevant to the geotechnical characteristics of the site and materials is presented elsewhere in the remedial action documentation, such information need not be repeated here but should be explicitly cross referenced.
I 3.1.1 Geotechnical eedmGeophyeeum4 Investigations performed to define the occurrence and properties of J,_il The scope and results of the geotechnical ::d investigations the underlying materials at the disposal site and the horrow areas, and the contaminated materials at the processing site should be presented...:f:r;:::
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In bti n'hrtiberiito the nyestigationsshouIdinc h
n following:
(a) a plot plan (s) clearly showing the outline of the disposal site, disposal cell, processing site, and/or borrow areas, and the locations of all borings, probes, pits, trenches, seismic lines, piezometers, and stratigraphic cross sections; (b) detailed final logs of borings, probes, pits, trenches, and geophysical investigations; and (c) a summary presentation of the scope of the investigations completed and an assessment of why it is adequate to 1
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9 C7 characterize the disposal site, contaminated materials, and borrow materials.
.f 3.1.2 Testing Program k 6edechniced Pr opu+fes of tAnkerisIs
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~6t The testing program should be consistent with the' needs of the proposed y&
remedial action and demonstration that the design will meet the long-term-E stability standards.
Test methods should be appropriately referenced, or k
described in detail where unusual conditions or deviations from stand:rd 3
practice exist.
Summary tables and plots should be provided which catalog the impurtant test resulty T h dt: q -_
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(R. 4) 3.1.3 Groundwater Conditions The scope and format for the information to be submitted on the groundwater conditions at the site are generally given in Section 5.1 of this document.
However, the following specific information is required under this section:
(a) the location of the groundwater table and the anticipated elevation range of temporal fluctuations in the groundwater level based on recorded field data; (b) the presence of perched, aquifer or artesian conditions; and cc o de n
si y
s th MF 3.1.4 Stratigraphy Based on the investigation
- program, the documentation should include stratigraphic profiles and cross sections of the tailings and the disposal site illustrating the detailed relationship of the proposed remedial action to the subsurface materials.
The cross sections should show the location and results of borings or other exploratory methods from which the information in the cross sections is derived.
3.2 Geotechnical Engineering Evaluation The geotechnical engineering evaluation should include information and analyses pertinent to the demonstration that the proposed design will resist certain conditions potentially disruptive of long-term stability, such as slope failure, excessive settlement, liquefaction, and cover cracking.
These analyses should take into consideration the design-basis events, i.e. design
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. earthquake (see section 2.1.4), design flood (see section 4.2.5), and extreme meteorological conditions.
If any of this information is presented in other sections of the rmedial action selection documentation, it coes not have to be repeated here, bi.t the appropriate sections should be explicitly referenced.
3.2.1 Slope Stability The slope stability analysis should be such that it sufficiently demonstrates, for both static and dynamic conditions, the stability of the slopes of the remedial action embankment and any other slope at the site whose failure could adversely affect the remedial action.
The presentation of the analysis should include:
(a) Locations Selected for Analysis - Cross sections and profiles of the slopes should be provided in sufficient number and detail to represent all significant slope, foundatiorr, and groundwater conditions.
The results of subsurface explorations and field and laboratory testing should be reflected on the developed sections and profiles.
The sections selected for slope stability analysis should be described including the basis for selection (e.g., at the location of maximum slope height or where weak foundation or in situ material is present).
M' (b) Adopted Design Properties - A summary and description of properties of the soil and rock comprising the slopes, and a o.re given discussion of the protadures used to estimate, from the 6 mW 3 * }
available field and laboratory data, conservative soil properties and profiles to be used in the analysis should be Wky rep <d provided.
The adopted design properties for fill materials b"?
need to be consistent with the compaction controls (density l
and moisture) to be specified in construction.
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l (c) Methods of Analysis - The methods of stability analysis (e.g., circular arc or wedge) need to be identified and desepeed.
Seepage and loading conditions that could reasonably be anticipated to occur during the long-term period that stability is to be assured should be dever%ed and analyzed.
(d) Results of Analysis - The results of the slope stability study should be sunnarized in graphic and tabular form and should clearly identify the sliding surfaces correlated with resulting factors of safety and the loading cases that were analyzed.
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3.2.2 Settlement I
The settlement analysis should demonstrate that the estimated settlemsr.ts especially differential settlement, will not lead to disruptive conditions such t
as surface water flow concentration or cracking of the radon barrier cover materials.
The presentation of the analysis should include the following information:
(a) Locations Selected for Analysis - A description of the areal extent and locations selected for the evaluation of l
settlement with the basis for the selection should be i
provided.
This should include the best, average, and worst conditions (from point of concern with settlement) at the site to enable an evaluation of the range of total and differential settlements at the selected locations.
Cross sections and profiles should be provided with the results of subsurface explorations (material types and layer thicknesses), fill placement, subsurface water elevations, and surface drainage features (as they may affect settlements) superimposed.
(b) Engineering Properties - A description of and the results of the testing conducted to establish soil engineering properties (e.g., compressibility characteristics) needed in the settlement analysis, including summarizing tables and graphs, should be provided. The soil parameters selected for input into the settlement analysis should be identified and the technical basis for their selection should be given.
(c) Methods for Estimating Settlements - The methods used to calculate the amounts (immediate,
- primary, total and differential) and the time rates of settlement should be described.,
The results of the (d) Results of Settlement Analysis settlement study should be described and sunnarized in i
tabular or graphical form.
The results should identify l
settlements estimated to occur before and after placement of the radon barrier materials and the time periods estimated for these settlements to occur.
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(e) Evaluation of Settlement Estimates - The significance of the settlement estimates should be discussed and assessed.
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Analysis indicating that settlements are unacceptably high or
-that time for consolidation is excessively long, to where detrimental effects on the radon barrier cover could occur, should logically lead to considerations for redesign or remedial measures.
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A descripth ef ;a,
' te.05 set ing and following ction should be provided includ n s
g typical details of the monitoring instal a
ns.
The settlement monitor s ould describe the prov paring
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3.2.3 Liquefaction Potential If the embankment (disposal cell) or foundation materials at the' disposal site are saturated, loose, cohesionless soils, then an analysis of the liwefaction potential of these materials is necessary for long-ters stability considerations. The analysis should include the following:
(a) A description of the method of analysis selected and the basis for its selection.
The need for a
detailed liquefaction analysis should be determined on a case-by-case basis and should consider the level of earthquake shaking, site stratigraphy, critical soil parameters, and the consequences of a liquefaction-induced failure; L
(b) A discussion of the appropriateness of the soil parameters 3$
used in the analysis;
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v v (c) A presentation of the results of the analysis (including E}
margins of safety) and a
discussion of its physica a r 8
significance in the context of the method of analysis used.
d, j 5
o 3.2.4 Cover Design f
Information should be provided to describe the cover's ability to perform for b
the required period of time and to resist degradation, to minimize infiltration
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and to minimize the effects of differential settlements.
The cover's ability
{., 2 9 to perform as a radon barrier is discussed in Section 6.1.
The information to T k E bentonite additive) T the basis for their se S
be provided should include:
types (e.g. Unified Soil Classification Systes or soil mixture (e.g., -
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c dh var M:y;r; ;r.d thich:::::: th t 00 prH: the ::v:r d::fr ;
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e a description, of the ap]11 cable field and laboratory investigations and 3 v) 3e D
testing that were comp etet and identification of the material properties li h / Permeability, mo' 5 turt -density relationships, gradation, shrinkage and Q
dispersive charactec W:s, resistance to freeze-thaw degradation, and chemical i
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compatibility); 4 % "E,.: %
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'*1" "mf t'; =5=rf:= eter Gems.; and 5) a description (with sketch'es) of any penetration (e.g.,
i monitoring well) through the cover system including details for sealing off and i
maintaining cover integrity.
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l If low-permeability membranes (geomembranes) are proposed as part of a cover
)
system cesig(n, the membranes need to be adequate'y described and their major q
properties e.g.,
physical and mechanical) provided.
The methods for installing the membranes in accordance with the manufacturer's recomunendations also need to be discussed.
Because of the lack of long-term performance and I
survivability records for polymeric membranes, the use of low-permeability membranes alone, to satisfy design and regulatory requirements for the cover
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system, is not recommended.
3.3 Construction Details In addition to the geotechnical consideration and design information discussed I
in the previous sections, the remedial action documentation should include i
information which details the construction features, methods, and verification L
testing.
This information is necessary to demonstrate that the selected ~
remedial action will be carried out in the field in such a manner that the performed remedial action meets the EPA standards.
3.3.1 Construction Methods and Features The information to be provided in this section should include site plans and engineering drawings that clearly convey the remedial action design features.
The engineering drawings should show dimensions, sections, and relative locations of the tailings disposal cell and any other facilities within the site boundary.
A it:il:d =;;rtte!
deri;tir :? th; cer.;t.;ti;a operatiene ehesid.l.v be p v,ided.
Construction specifications should be included in this section, t;t ;nd ;;;,
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h 3.3.2 Testing and Inspection This section should. include description of the methods, procedures and frequencies by which the construction materials and activities are to be tested j
and inspected to verify compliance with the design specification requirements.
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In general, this section will be comprised of the information that has previously been included in the site specific Remedial Action Inspection Plans
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