ML20134B411
| ML20134B411 | |
| Person / Time | |
|---|---|
| Issue date: | 08/02/1985 |
| From: | Palladino N NRC COMMISSION (OCM) |
| To: | Markey E, Wyden R HOUSE OF REP., ENERGY & COMMERCE |
| References | |
| NUDOCS 8508150612 | |
| Download: ML20134B411 (187) | |
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UNITED STATES h,
NUCLEAR REGULATORY COMMISSION h
.t WASHINGTON, D. C. 20555 August 2, 1985 CHAIRMAN The Honorable Edward J. Markey, Chairman Subcommittee on Energy Conservation and Power Committee on Energy and Commerce United States House of Representatives Washington, DC 20515
Dear Mr. Chairman:
Thank you for your letter dated June 28, 1985 requesting NRC comments on several reports relating to investigations of the Hanford, Washington site as the location of a potential high level waste repository.
Your letter requested our review of the attached USGS letters and the report entitled, " Heat, High-Water, and Rock Instability at Hanford" and our views on four specific questions. provides the staff's specific responses to your questions and other significant points resulting from our review of the attached material.
On a continuing basis since the early 1980's, the NRC staff has been reviewing the site investigations at Hanford.
In these reviews the staff has raised to the Department of Energy the issues discussed in your letter and accompanying reports.
Last March the staff completed an extensive review of the DOE Draft Environmental Assessment (EA) prepared on the Hanford site in support of DOE's process of selecting five sites as suitable for nomination for detailed site characterization.
In this review (Attachment 2), the staff reiterated these concerns and identified specific issues that need to be addressed by DOE in the final EA.
We hope that this response has adequately addressed your questions and concerns.
Sincerely,_
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Nunzio)J.Palladino v-Attachments:
1.
Responses to Questions 2.
NRC Comments on BWIP EA cc:
Rep. Carlos Moorhead 8500150612 850802 COMMS NRCC PDR CORRESPONDENCE PDR
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8 g *.s e j CHAIRMAN August 2, 1985 The Honorable Ron Wyden Subcommittee on Energy Conservation and Power Committee on Energy and Commerce United States House of Representatives Washington, D. C.
20515
Dear Congressman Wyden:
Thank you for your letter dated June 28, 1985 requesting NRC comments on several reports relating to investigations of the Hanford, Washington site as the location of a potential high level waste repository.
Your letter requested our review of the attached USGS letters and the report entitled, " Heat, High Water, and Rock Instability at Hanford" and our views on four specific questions. provides the staff's specific responses to your questions and other significant points resulting from our review of the attached material.
On a continuing basis since the early 1980's, the NRC staff has been reviewing the site investigations at Hanford.
In these reviews the staff has raised to the Department of Energy the issues discussed in your letter and accompanying reports.
Last March the staff completed an extensive review of the DOE Draft Environmental Assessment (EA) prepared on the Hanford site in support of DOE's process of selecting five sites as suitable for nomination for detailed site characterization.
In this review (Attachment 2), the staff reiterated these concerns and identified specific issues that need to be addressed by DOE in the final EA.
We hope that this response has adequately addressed your questions and concerns.
Sincerely,
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Nunzio J. Palladino Attachments:
1.
Responses to Questions 2.
NRC Comments on BWIP EA
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Question 1 The report raises the possibility that all major repository perfonnance.
standards required by the Nuclear Regulatory Comission for long-term containment of high level nuclear waste may not be met for the Hanford s'ite.
Please identify any Hanford site characteristics which currently do not, or potentially may not, meet NRC performance standards for a repository.
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NRC Staff Response
'It should be recognized that detailed site characterizaticn has not been initiated at any of the DOE sites.
In its review of DOE's recent Environmental
,l Assessment (EA) of the Hanford Site, the NRC staff did not conclude that a disqualifying condition was clearly present or a qualifying condition clearly absent at the Hanford Site.
However, due to the many uncertainties regarding site characteristics at Hanford, as well as the other sites being considered, a final determination of compliance with NRC standards can only be made following detailed site characterization. '"
What the staff did point out to DOE in its review of the draft EA was that many of DOE's analyses were overly optimistic and failed to properly. recognize potential problems and issues. The NRC staff recomended that DOE reconsider j
its findings on individual guidelines based on its comments and those of others, and following this, reevaluate the ranking of the sites.
Changes j
in findings on specific guidelines could change the comparative ranking of the sites.
Furthermore, as part of the NRC staff's ongoing prelicensing interactions with j
DOE, the staff's ongoing review of site investigations at Hanford since the early 1980's has identified several conditions that could potentially lead to i
site failure.
These conditions hava been analyzed by the staff, discussed with DOE and documented in meeting reports, letters to DOE, and the NRC's staff analysisofDOE'sSiteCharacterizationReportissuedin1982,(Site i
Characterization Analysis,(SCA, NUREG-0960)].- (Attached) 1 The main conditions identified in the NRC staff reviews that could cause the site to fail concern groundwater travel time, tectonic stability, and the high 3
state of stress and rock stability.
The conditions must be taken into consideration in the design, construction and operation of a repository.
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The NRC staff's EA coments also address these concerns in the instances where they were not adequately addressed by DOE in the EA.
For example, the staff addressed the concerns regarding groundwater travel time in Major Coment 1 and tectonic stability in Major Coment 4.
The significance of core discing which is related to the high state of stress and can be indicative of rock bursting was pointed out by the NRC staff in 1982. The importance of inferred, unusual stress field was discussed with DOE at a technical meeting in September 1982.
Subsequently, the DOE made changes in the concepts for the repository design to accomodate the inferred stress field. The stress field is discussed further in the answer to Question No. 4.
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2 As an example of one of the major uncertainties that exists at the present time at the Hanford site, NRC staff comments on the Draft EA (Detailed Comments 6-101 and 6-102), indicate existing data are too unreliable and unrepresentative to make any substantive conclusions regarding groundwater travel times.
At this time, any estimates of groundwater travel time are far from conclusive, and a
" fatal flaw" in the site has not been identified.
However, there is a possibility that future site characterization may indicate that the groundwater travel time through the fractured and brecciated basalts and sedimentary interbeds beneath the Hanford site to the accessible environment will not meet the 10 CFR 60.113(a)(2) performance objective.
In any case, detailed site characterization will be necessary to fully address this question.
The unfavorable conditions discussed above are in many cases the same as those identified in Dr. White's report.
In addition, there are other concerns, such as high temperature and host rock thickness, also identified by Dr. White, that while not directly related to NRC radiological public health and safety and environmental protection charters and related performance standards, must be weighed carefully by DOE in their evaluation of the Hanford site against the Siting Guidelines on Ease and Cost of Siting, Construction, Operation, and Closure.
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Question 2 i
l The U.S. Geologic Survey has pointed out that a number of exploratory activities in and around the Hanford site, particularly beyond the 10 kilometer i
radius covering the Pasco Basin, should be completed prior to the shaft construction planned for site characterization. The USGS also noted that construction of a shaft prior to the completion of these activities would prevent a sound geohydrologic picture from emerging.
Does the NRC agree that measurements are needed beyond the 10 kilometer radius in the Pasco Basin?
l Does the NRC agree that shaft construction prior to completion may interfere with an adequate set of measurements being taken? If not, please give detailed reasons.
If yes, should shaft construction at Hanford be postponed until these j
measurements are complete?
5 NRC Staff Response f
Question 2 consists of two parts:
i a)
"DoestheNRCagree[withtheUSGS]that[hydrogeologic]measurementsare needed beyond the ten-kilometer radius in the Pasco Basin?"
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TheNRCstaffhasidentifiedintheSCA(NUREG-0960)andinsubsequentletters to DOE the need for information on regional hydrology (i.e., from beyond the j
ten-kilometer radius) for evaluation of recharge and discharge locations, hydraulic parameter variability, flow directions and velocities, and structural geologic controls on groundwater flow. The NRC staff has recomended that DOE i
obtain information both on and off the Hanford site, and both within and beyond the ten-kilometer radius from the exploratory shaft location. DOE has already drilled and tested several holes beyond ten kilometers.
In addition. DOE has recently proposed the construction of additional boreholes outside of the
, and is currently engaged in an imediate area of the proposed repository (involving Rockwell Hanford Operations, interagency working group investigation USGS, and Battelle Pacific Northwest Laboratories) of the regional ground-water flow system. These activities are expected to contribute to the resolution of several issues of concern to both the USGS and NRC' staff.
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Does the NRC agree [with the USGS] that shaft construction prior to l
completion may interfere with an adequate set of measurements being taken?
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The NRC staff agrees that shaft construction prior to completion of hydrologic testing may well interfere with an adequate set of hydrologic measurements.
i Since issuance of the SCA the NRC staff has met with DOE several times on i
hydrologic testing at the Hanford site and in December, 1983, issued a Site Technical Position,1.1, Hydrologic Testing Strategy for the Hanford Site.
One of the main concerns identified in developing the testing strategy was the need to avoid major perturbations to the hydrologic system, such as shaft sinking, i
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4 which may interfere with hydrologic characterization of the site.
NRC studies indicate a potential for shaft sinking to cause perturbations to the hydrologic conditions at large distances (possibly thousands of meters) which may take years to recover. Leaky or failing shaft liners could also significantly perturb the hydrologic conditions. The NRC staff has suggested that DOE evaluate these effects in terms of the extent of spatial and temporal perturbations to hydraulic head prior to shaft drilling. The timing of shaft construction with respect to hydrologic test measurements is central to implementation of the NRC's staff Technical Position 1.1.
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Question 3 Compliance with the spirit and ir. tent of the Mine Health and Safety Act and associated regulations is requirad by the NRC standards specified in 10 CFR 60.
4 Yet neither DOE's Site Characterization Report, nor DOE's Environmental Assessment appear to deal in a cetailed and substantive way with the i
requirements of the Act. Additionally, the question of possible conflicts between altering mine safety objections and achieving long-term containment is not addressed. The Health and Energy Institute Report raises both the safety concerns and the possible conflicts, particularly those arising from rock bursting and resulting hydrologic phenomena.
Please comment on whether you agree with the concerns raised in the report.
NRC Staff Response In the NRC staff's July 31, 1984 comments on DOE's draft Mission Plan, the NRC Staff I
commented on the need for DOE to discuss in the Mission Plan the responsibility and objectives of an occupational health and safety program.
In their discussion on occupational health and safety in the Draft EA, DOE states on page 4-39 that in order to minimize personnel risks associated with underground activities, DOE would follow Order 5480.1A which includes:
Federal Mine Safety and Health Act 1
Tunnel Safety Orders of the State of California i
Mine Safety Orders of the State of California j
Emergency Response Plans in Accordance with DOE Order 5500.3.
In regard to conflicts between mine safety and achieving long-term i
containment, the NRC staff does not consider this a concern at this time. Many factors, such as the stability of underground openings, are needed not only for worker safety but also for waste containment. With regard to the specific example in the Health and Energy Institute Report of the use of blasting to 1
avoid injury from rock bursts, such blasting would not necessarily affect waste isolation. Current mining methods allow for controlled blasting and shotcreting which may contain minor rock bursts.
In addition, destressing of l
the rock will not affect an extremely large portion of the host rock, thereby minimizing the possibility of major alterations in the groundwater hydrology.
Thus the possible conflict between mitigative measures and the long-term containment does not appear imminent.
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Question 4 The horizontal to vertical stress ratio is critical to the issue of rock bursting, and all of the stress ratio measurements taken by DOE were greater than 2.0.
It appears that DOE used a design stress ratio of 2.0 for the site, despite the fact that their measurements averaged 2.33 (with a high of 2.7) which is only 25 percent below the DOE disqualification mark of 3.0.
The evidence from the core samples indicates that intense core discing is frequent when the stress ratio is greater than 2.0, and that this core discing is probably a forewarning of rock bursting.
A.
Is the stress ratio of 3.0 an appropriate disqualifying level, or should a site be disqualified at some lower level?
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Should a site like Hanford, which demonstrates core discing problems be disqualified? Explain?
NRC' Staff Response A.
The NRC staff has been aware of the problems associated with high m
horizontal stresses for some time, having viewed the evidence of high horizontal stresses such as core discing and borehole wall spalling, and has documented them in letters to 00E.
However, it is not a usual engineering practice to assign a disqualifying horizontal to vertical stress ratio value for the purposes of repository design and construction.
The influence of horizontal stresses in rock construction does not depend entirely upon the value of horizontal to vertical stress ratio.
Site specific factors such as the strength of the rock mass and the joint spacing also play a major role in combination with the stress ratio value.
The stress ratio is but one of a number of critical parameters which must be used, collectively, as the basis for repository design.
All critical parameters must be analyzed individually and collectively to develop an optimum design.
00E now recognizes that the average horizontal to vertical stress ratio is approximately 2.5 to 1 as stated on page 6-200 of the Draft Environmental Assessment (EA), December,1984.
Recent 00E design documents are being revised to incorporate this increased stress ratio.
Furthermore, DOE has not concluded that a stress ratio of 3.0 should be a disqualifying level.
The DOE states on page 3-40 of a working draft of the Draft EA (February, 1983) that according to preliminary estimates a maximum stress ratio of 3.0 could make the construction of a repository economically unattractive.
DOE does not state or imply that, at a stress ratio of 3.0, construction will be technically impossible or that it will definitely be economically unattractive.
It appears that the authors of " Heat, High Water, and Rock Instability at Hanford" could have misinterpreted the DOE's statement as a disqualifying condition.
c Based on all of the information discussed above, at this time it would be inappropriate to develop a disqualifying criteria based just on horizontal to vertical stress ratio.
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In general, the NRC staff agrees with the concerns raised regarding core discing problem.
The phenomena of core discing is generally thought to result in high i
horizontal stress areas.
Rock bursting is also associated with the areas of similar stress conditions. While the NRC staff agrees that rock bursting may be present during construction at Hanford, the staff does not feel that the potential for rock bursting alone is a compelling reason to disqualify the site, because mitigative measures can substantially minimize the hazards associated with the phenomena.
In the Draft EA, DOE recognizes the problem and gives mitigative measures to control the 1
l potential for rock bursting. Also, in its site selection process, the DOE has considered rock burst as a potentially unfavorable condition.
However, DOE must also consider this problem in its evaluation of the Siting Guidelines on Ease and Cost of Construction.
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Review of " Heat, High Water, and Rock Instability at Hanford" The NRC staff reviewed the subject report and the supplement by Dr. White earlier this year. All of the technical areas of concern presented in these documents have been raised to DOE by NRC staff over the past several years. As discussed in responses to the previous questions these concerns and their significance are discussed in detail in the SCA and the NRC staff comments on the draft EA. The NRC staff's review of the documents has not I
identified any new technical information of any significance.
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March 20, 1985 Mr. Sen C. Rusche, Director Office of Civilian Radioactive Waste Management U.S. Department of Energy Washington, D.C.
20585
Dear Mr. Rusche:
The NPC staff has completed its review of environmental assessments (EAs) issued by the 00E on Decerber 20, 1984, in support of the site-selecticn process established by the Nuclear Waste Policy Act (NWPA) of 1982 for the first geolcgic repository. The EAs contain assessments of the nine potertfally acceptable sites that 00E has identified for the first recository in accordance with the requirements of Section 112 o' NWPA and General Guidelines for tne Pecommendation of Sites for Nuclear 'aaste Repositories (10 CFR 960--the siting guicelines) developec pursuant to Section 112.
The NPC staff, in conducting its review, attenstec to give essentially equal attention to all nine EAs.
The hRC staff recognizes the magnitude of the 00E effort -- the nine EAs consisted of about 9,000 pages supported by more than 3,000 reference documents
-- and the difficulty of its ranking process since this called for a consideration of the many, widely varying conditions and situations which exist at nine sites.
These NRC comments should be viewed as a part of the continuing interface
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between the staffs of the DOE and NRC which will lead to early identification of potential licensing issues.
In addition, our coments are -influenced by the provisions of the NWPA for NRC to adopt the DOE Environmental Impact Statement (EIS) to the extent practicable. We believe the EAs and 00E's reaction to the NRC comments will affect the ability of 00E to produce an EIS that NRC can 1
adopt. As 00E is aware, adoption of the EIS and early identification and resolution of potential licensing issues will have significant impact on ultimate resource needs and schedules in this important national program.
Therefore, we believe that the opportunity afforded by the EAs for early interaction between NRC and 00E on site issues will be beneficial to the progress of the repository program.
Our coments focus on some significant areas where, we believe, reexamination by DOE is necessary. The substance of our comments is founded principally on our view of the existing factual support for the 00E conclusions, the treatment of uncertainty in DOE's use of existing data, and on logical alternative treatments of data which, we believe, may lead to logical alternative or modified conclusions.
In no case did the staff conclude that a disqualifying condition was clearly present or a qualifying condition clearly absent at the
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site being investigated.
NRC bas not attempted, nor do we consider it appropriate for NRC to attempt, a rating of sites.
We believe that resoluticn of our comr:ents coulc be achieved by COE reexamination of existing data and, based en this reexamiration, a reconsideration by COE of its conclusions as they may affect findings en individual guidelines and thus the ccmparative rar. king of sites. We reccgnize as you do that, at this stage of the site investig? tion and screening process, there is inherent uncertainty in many site features and that final resclution of uncertainties--such as these alluded to in cur cements--must awatt detailed site characterization.
The staff presents its cor: rents in two parts.
First, it presents major j
ccu ents.
Second, detai!ed ccments are presented on each of the chapters of the EA.
?he major corrects are those ccircents which the staff considers may potertially lead COE to a charge in EA findings with respect to a specific guideline or may affect COE's ccmparison cf sites.
In some of the detailed coments, the staff identifies areas where discussions supporting EA findings are core certain than we believe the data supports.
If such supporting discussions were considered in the comparison and ratings of sites, these detailed correents could be as significant as those labeled major coments.
In its coments, the staff attempted to describe the significance of the coment and actions which may be appropriate for resolution.
Recognizing the importance of the decisions that the DOE is making in the repository site-selection process and in view of the schedules that are prescribed in NWPA, we are available to meet with 00E representatives to discuss our coments to assure that they are clearly understood.
Sincerely, 3
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John G. Davis, Director
'. Office of Nuclear Material Safety and Safeguards
,1. i i ;.. i to i.-.Tr._ 1 NRC COMMENTS ON COE ORAFT ENVIRONMENTAL ASSESSMENT FOR THE HANFORD SITE March 20, 1935 I
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HANFORD ORAFT EA REVIEW CONTRIBUTORS f
Robert Wright Project Manager Project Management Warren Rehfeldt Design / Rock Mechanics Sher Bahadur Michael Blackford Geology / Geophysics i
Nonradiological Al Brauner Transportation David Brooks Geochemistry l
John Buckley Design / Rock Mechanics Arch./ Cultural / Historic Lou Sykoski Resources and Socioeconomics Kien Chang Waste Package Aesthetic Resources, and Natural Don Cleary Resources i
Neil Coleman Hydrology Radiological Transportation John Cook On Site Representative Boe Cook Maxine Dunkelman Performance Assessment i
Matthew Gordon Hydrology Clarence Hickey Aquatic Ecology Surface Water Hydrology Ted Johnson William Lake Radiological Transportation Gerry LaRoche Terrestrial Ecology William Lilley Environment /Socioeconomics i
Earl Markee Meteorology and Air Quality Chris Pflum Environmental Bob Samworth Water Quality and Noise Jerry Swift Radiological Impact Kristin Westbrook Geology / Geophysics Everett Wick Waste Package i
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1 INTRODUCTION Backcround i
On December 20, 1984, the DOE issued draft environmental assessments (EAs) for l
nine potentially acceptable sites for the nation's first nuclear high-level waste repcsitory.
Issuance of final EAs will be in accorcance with the Nuclear Wasta Policy Act of 1982 (NWPA) which directs the U.S. Department of Energy (00E) to issue an EA for eacn site that the Secretary nominates as being suitable for site characterization.
Public review and comment were solicited on draft EAs for a ceriod ending en March 20, 1985.
Frem among the nine potentially acceptable sites, five sites are being proposed for ncmination as being suittble for site characteri:ation.
Following the issuance of the final environmental assessments, COE will formally ncminate at least five sites as suitable for site characteri:ation and reccmmend at least three of the nominated sites to the President fcr site characteri:atien as canctdates for the first repository.
Each craft environmental assessment contains:
(a) a description of the cecision process by wntch the site was selected; (b) infor-ation on the site and its surroundings; (c) an evaluation of the effects of site characterizaticn activities; (d) an assessment of the regional and local impacts of Iccatino a repository at the site; (e) an evaluation as to whether the site is suitable for site enaracterization and for development as a repository; and (f) a comparative evaluation of the site with other sites that have been considered.
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The NWPA and NRC regulations governing licensing of the geologic repository j
provide for consultation between COE and NRC staffs prior to fomal licensing to assure that licensing infomation needs and requirements are identified at j
an early time.
In accordance with the NRC/00E Orocedural Agreement on J
repository prelicensing interactions, NRC and CCE staffs have been conducting such consultations. According to NWPA, the environmental assessments are to provide a summary and analysis of data and infomation collected to date on sites which the 00E intends to nominate for site characterization. Therefore, they present an important opportunity for NRC and COE staffs to censult on the i
issues that exist at each site which must be addressed for site l
characterization.
They also afford an opportunity for the NPC staff te point cut at an early stage in COE's repository program potential licensing problems with a site if they were fcund to exist on the basis of available infomation.
NRC Staff Review The staff conducted its review of the EAs according to the NRC Division of Waste Mana*gement's " Standard Review Plan for Draft Environmental Assessments
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4 (Dec 12, 1984)." Because of the limited. time available for review and the vast amount of data and information existing for the nine sites, the staff had prepared for the draft EA reviews well before their receipt.
Preparation base for each site; 2) selected detailed reviews cf data; 3)g data /infomation included:
- 1) broad familiarization with the everall existin i
development of a j
clear understanding of the guidelines; and 4) development of preifminary views j
and issues through reviews of existing data and scoping reviews of preliminary 2
EA drafts.
This early preparation and familiarization with the existing data base has allowed the staff to determine if the conclusions and findings in the i
EAs are consistent with the available data.
l In its review, the staff has sought to identify potential safety issues through a review of 00E's application of the siting guidelines.
The staff has focused i
on the analyses and technical evaluations that are made on individual guidelines which constitute the factual basis upon whien the site comparisons 1
are made by 00E.
The staff reviewed the available data, interpretations, assumptions and perfor-ance assessments in the EA and *ts references that COE used to substantiate its evaluation of a site against the guidelines.
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comenting on the EAs, the staff has recognized that the level of information which exists on each site is not equivalent to what will be necessary to make l
findings about the suitability of the one site that is proposed for development as a repository.
The staff has reviewed the evaluations and conclusions which are called for at the EA stage by the siting guidelires.
These guidelines recognize the inherent uncertainties that will face any site before detailed j
site characterization.
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The staff's review and coment on the evaluations and :enclusions on the siting guidelines effectively identified issues which are relevant to potential safety 4
issues.
In its concurrence action on the siting guidelines, the Comission j
found that the guidelines are consistent with the recuirements of its own
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regulations on geologic repositories (10 CFR Part 60). Therefore, while the
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staff has not identified in each case how its coments relate to the specific requirements of 10 CFR part 60, we feel that they serve to identify those issues which are relevant to potential licensing of each site based on i
infomation currently available and which will need to be resolved during site characterization.
l The staff also comented on the analyses of environmental impact! of site characterization activities and repository operation with the intent of assisting 00E's preparation of the final EAs. However, the staff has not l
performed a detailed review with regard to the site characterization plans in l
Chapter 4 or the repository descriptions in Chacter 5 of the EAs. The staff only comented on those aspects of site characterization plans, such as the 1
need for characterizing the gechydrological regime beneath Canyonlands Park,
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whicn neec to be censidered to evaluate the site against the siting guidelines, at this time.
Site characterization plans will be reviewed upon receipt of such plans in accordance with the NWPA and in other consultations with the DOE under the interagency agreement governing rep'ository prelicensing matters (c8 FR 38701); the staff's review and positions will be documented in site characterization analyses at that time.
NRC Staff Ccennent-Summary In no case did the staff cerclude that a disqualifying condition was clearly present or a qualifying cendition clearly absent at the sites being investigated.
To a large extent the EAs recognize that uncertainties exist at each site.
Mcwever, in scme instances, the full range of uncertainty that exists about certain factors affecting site suitability is not recogni:ec in the discussion succerting the EA findings.
The staff noted that in a number cf instances the EAs make conclusions and findings which are net supcorted by existing data or wnich existing data indicate are not conservative.
In these instances, the staff points out soecific data and other information which indicate that EA. conclusions are not realistically conservative as required by 10 CFR Part 960 (10 CFR Part 960.3 requires that assumptions mace in EA evaluations be... " realistic but conservative enough to underestimate the potential for a site tcireet the qualifying condition of a guideline..."),
for example, we point out information un hydrologic cenditions at several sites which is net fully documented in the EAs and which could realistically succort less optimistic conclusiens about grcundwater travel time than those presented in the EA.
In each ccement, the staff has attempted to describe the sienificance of the ccreent and to racccrend what 00E might do to resolve tne coment. Ultimately, it may be found unnecessary to completely eliminate all of the uncertainties about site features that are identified in the coninents.. It is expected that thrcugh further investigation it can be shown that some of these uncertainties are ccmpensated for by other site features which assure overall system guidelines are met.
(For example, some questions about geochemical prcperties may be mooted or lesstned in importance by development of infonnation indicating that there are very favorable and compensating groundwaterconditions.) Nevertheless, it is essential that all potential -
problems and uncertainties about sites be explicitly identified at this stage so that site-screening decisions are based on complete assessment of the facts and that future site characteri:ation work.is complete.
In peinting out deficiencies in DOE's evaluattuns of individual sites, the staff has commented on DOE's evaluations and findings with respect to the s
various in'dividual factors which are important to site suitability (i.e.,10 CFR Part 960 guidelines on gechydrology, geochemistry, rock characteristics,
4 etc.). We expect that the DOE analyses in Chapter 1 thecugh 6 will be revised in light of cur cceents. The staff therefore recccrends that 00E reconsider its ratings and ranking analyses of sites in Chapter 7 so that the overall ccmparison of sites and resulting decisions are consistent with sup;orting evaluations and findings on individual factors.
It is the staff's view that by recogni:ing uncertainties identified in cur ccmments and reexamining its assessments in light of the other technical concerns that we raise, the environmental assessments and related decisiens will be strengthened.
Presertation cf EA Cements The staff presents its cc=ents in two parts.
First, it presents major comments.
The order in which tnese ecmments Are presented has no special significance; the ceder is governed by the fact that scme coments, wnich help the reader underst3nd others, ccme first.
Second, catailed cements are presented on each of the chapters of the EA.
The major cements are those cements which tee staff considers may potentially lead COE to a change in EA findings witn respect to specific guideline or eay affect the relative ratings of sites.
In sete of the detailed cements, the staf# identifies areas where the discussions supporting the EA findings are more certain than we believe the data succorts.
If such supporting discussions were considered in the cceparison and ratings of sites, these detailed ccmments could be as significant as t, hose labeled najor corrents.
Many of the staff's cements appear identical for cifferent sites because the information presented by 00E fn the EAs was often identical and therefore would result in the same cement, particularly when sites are in the same gechydrologic basin.
Similar cements do, hcwever, take into consideration differences resulting frcm site specific information.
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1 MAJOR CC.vMENTS I
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MAJOR COMMENTS CCMMENT #1 Ground-Water Travel Time Guidelines on Geohydrology 10 CFR 960.4-2-1(b)(1) and 960.4-2-1(d).
In the draft EA, the DOE concludes that the pre-waste-emplacement ground water travel time along any path of likely and significant radionuclide travel from the disturbed zone to the accessible environment is expected to be well in excess of 10,000 years (Sections 6.3.1.1.2, 6.3.1.1.11, 6.3.1.1.12, and 6.4.2.3.5).
In support of its conclusion, the DOE has performed several preliminary deterministic and stochastic studies of ground-water travel time which have yielded a wide range of travel time estimates.
The preliminary estimate which the 00E considers most representative of site conditions, as presently understood, is 81,000 years (median) with a more than 0.95 probability of exceeding 1,000 years (page 6-81).
The NRC believes there are several questionable areas with respect to 00E's finding on ground-water travel time. These areas are:
- 1) the applicability of previously published travel time estimates (see detailed comment 6-12); 2) the reliability and representativeness of the data base for transmissivity, hydraulic gradient and effective thickness (see detailed comments 6-15 and 6-105); 3) the treatment of these data in deterministic and stochastic models (see detailed comments 6-101, 6-12, and 6-102); 4) the treatment of the numerical model geometry (see detailed comment 6-102); and 5) the definition of the orientations and lengths of flow paths from the disturbed zone to the accessible environment (see detailed comment 6-12).
With regard to item (2) above, the NRC believes the limitations of the available data do not allow high confidence to be assigned to any travel time estimates at this time.
Nevertheless, a rough evaluation by the 00E of the ability of the site to meet the ground water travel time conditions set in the Guidelines (960.4-2-1(b)(1) and 960.4-2-1(d)) is necessary at this time.
As an aid in reviewing the DOE's preliminary conclusions (page 6-81), which are based on the existing hydrologic information base, the NRC staff has calculated alternative median travel times based on the same information.
These calculations, which are consistent with 00E's conceptual model, illustrate the impact of problem area (3) noted above.
They demonstrate that substantially lower estimates of median travel time can result from reasonable interpretations of the existing data (see detailed comment 6-101) and the DOE's conceptual medel. Most of these estimates are less than 10,000 years, and some are less than 1,000 years, which causes the NRC to question the DOE's evidence for the finding on favorable condition 960.4-2-1(b)(1) and discualifying condition 960.4-2-1(d).
Because of 1) the simolified nature of the NRC's I
calculations and~2) questions about the reliability and representativeness of the underlying data base used, especially for the large-scale hydrologic properties of the site, these estimates should not be construed as accurate or
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2 reliable predictions of-actual site conditions.
However, the parametric analysis, and an additional analysis exploring the impact of problem area (4) noted above (see detailed comment 6-102), raise significant questions regarding the defensibility of the DOE's conclusion that the ground-water travel times can preliminarily be inferred, based on the existing data, to be well in excess of 10,000 years, or that there is a high probability that the travel times would be greater than 1,000 years.
We suggest that the DOE thoroughly reexamine the available information, considering the questions noted above with respect to the DOE's predictions of hydrologic performance.
If the DOE considers that the findings presented in the draft EA should be maintained, further support of this position should be provided, specifically addressing the points noted above and in our detailed comments.
COMMENT #2 Changes that Could Affect the Geohydrologic Regime Guidelines on Geohydrology 10 CFR 560.4-2-1(c)(1); Climatic Changes 10 CFR 960.4-2-4(c)(2); and Human Interference 10 CFR 960.4-2-8-1(c)(5).
The 00E concludes that the potentially adverse condition relating to changes in geohydrologic conditions sufficient to significantly increase the transport of radionuclides (960.4-2-1(c)(1)) is not present.
In arriving at this conclusion, the 00E considers and dismisses two processes that could potentially induce changes in geahydrologic conditions.
Specifically, these processes include: 1) climatic changes and 2) thermal loadings originating from decay of emplaced nuclear wastes.
However, the NRC considers that these, and human-induced conditions not considered by the 00E. may significantly alter the geohydrologic regime and consequently affect repository performance.
In evaluating the effects of climatic changes on the geohydrologic system the 00E concludes that significant climatic changes are not to be expected during the next 10,000 years.
Based on this conclusion, the DOE determines that the potentially adverse condition of significantly increased radionuclide transport caused by climatic changes is not present at Hanford (960.4-2-4(c)(2)).
However, the NRC concludes that significant climatic variations cannot be discounted over the next 10,000 years. The potential for climate change includes both potential for significant warming, or for significant cooling (see detailed comments 6-3,8 and 6-39, respectively).
The 00E concludes that proglacial catastrophic flooding would be the most probable disruption 1 scenario associated with potential _ climatic changes that could significantly affect the hydrologic system.
Because this catastrophic flooding was associated with the late ablation phase of continental glaciation, the NRC agrees _that it is not likely to recur over the next 10,000 years.
However, other consequences of either significantly warmer or cooler climatic trends have not been discussed by the 00E. -For example, smaller-scale climatic variations may result in future channel migrations of the Columbia River and
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its tributaries in response to increasing discharges and sediment loads fed by meltwaters from reactivated mountain and valley glaciers. Mountain glaciers presently exist in the northern portions of the Columbia's drainage basin.
These could be reactivated and subsequently ablated in response to relatively small-scale climatic changes.
If future channel displacements of the Columbia occur within the area of the Hanford Reservation they could dramatically alter regional patterns of recharge and discharge and may significantly change radionuclide transport conditions within local basalt and interbed aquifer systems (see detailed comment 6-39). Overall, in the NRC's view the potential for both cooling and warming trends, and the consequences thereof, should be more closely examined by the 00E.
With respect to heat effects caused by radionuclide decay, the DOE concludes that thermal loading is precicted to extend a distance of several hundred meters frcm the repesitory.
The CCE dismisses the significance of this thermal loading because it represents a limited lateral extent relative to the 10 km lateral distance to the defined accessible environment.
However, studies by the NRC staff and others (see detailed comment 6-18) suggest that post-emplacement thermal leadings may be sufficient to sienificantly increase hydraulic gradients, especially along vertical profiles in close proximity to the repository. Such a change in nydraulic gradients would be expected to significantly change flow paths and rates.
The result could be a corresponding decrease in ground-water travel times, particularly along any existing vertical flow paths. Geochemical effects, resulting in volume reductions in fracture-filling clays, that may accompany the thermal loadings could also significantly affect the gechydrologic regime (see detailed comment 6-27).
In addition to the two mechanisms for significant changes in the gechydrologic system discussed above, which the DOE considered and dismisses, the NRC concludes that human-induced changes to the geohydrologic system may significantly affect rates of radionuclide transport to the accessible environment.
These human-induced changes could be caused by onsite wastewater disposal activities and offsite ground water and surface water withdrawals, resulting in aquifer recharge anc perturoation.
Piezometric data suggest that artificial recharge of the unconfined aquifer system, caused by four decades of wastewater disposal activities at the Hanford Site, may ce causing a downwardly progressing increase in nydraulic heads in the confined basalt and interbed aquifers.
If this condition proves to be correct it would have considerable significance with regard to vertical ground-water travel paths and travel times, especially in the presence of post emplacement thermal loadings during the period after wastewater disposal ceases (see detailed comment 6-18).
Other human-induced geohydrologic perturbations may be caused by dam construction, offsite ground-water withdrawals for irrigation and other purposes, and irrigation derived from Columbia River waters (see detailed comment 6-18).
Such activities would result in greatly increased surficial recharge rates over large areas.
Under the postclosure geohydrologic guideline (960.4-2-1(c)(1)) it is stated that the potentially adverse condition is'not
4 likely to exist (page 6-76).
However, on page 6-143 the DOE assumes that the potentially adverse condition (960.4-2-8-1(c)(5)) regarding impacts of human activities, including ground-water withdrawals and surface impoundments, on the gechydrologic system could be present.
This disparity in findings under the guidelines should be resolved by the 00E (see detailed comment 6-57).
Based on the above discussions the NRC considers that there is reasonable doubt that the potentially adverse conditions are absent. The DOE should reevaluate the potentially adverse scenarios described above and revise the EA either to further support its conclusion that the potentially adverse condition (expected changes in geohydrologic conditions sufficient to significantly increase rates of radionuclide transport) is absent or to reverse one or both of its negative findings with respect to the potentially adverse conditions [960.4-2-1(c)(1) and 960.4-2-4(c)(2)]. The DOE's finding under the postclosure geonydrologic 4
guideline 960.4-2-1(c)(1) should be consistent with the finding under guideline i
960.4-2-8-1(c)(5) regarding forseeable human activities.
COMMENT #3 Geochemical Environment General Geochemical Guideline 10 CFR 960.4-2-2 l
In the draft EA Executive Summary, attention is drawn to the inferred, favorable geochemical environment at Hanford.
"There is also evidence that the 4
reference repository location has chemically reducing conditions that will promote precipitation and will maintain radionuclides in their least mobile i
state." (draft EA, page 15) The NRC review of the Hanford draft EA found inadequate data and analyses to support the DOE statements about the reducing nature of the basalt ground water and the geochemical environment, and that the DOE analyses did not adequately address well-known problems of interpretation of redox information.
Based on this review, the staff considers that the EA does not provide convincing support for the key conclusions in the preceding citation.
The solubility of radionuclides at Hanford is largely related to the redox conditions in the ground-water.
The DOE analysis of redox conditions and reactions, as presented in the EA (pages 6-90/91/92/95/96) and cited j
references, do not support a conclusive evaluation that:
(1) expected redox conditions are as reducing as the -0.3 volts used for EA calculations; and that (2) expected reactions will maintain redox-sensitive radionuclides in low solubility and high sorption states.
Concerning point (1), the DOE-sponsored investigations of ground-water [Early, et al. (1982 and 1984) and DOE (1982), among others] report that measured redox conditions range from about +0.35 volts to -0.2 volts, and that calculated values range as low as -0.4 volts. However, redox measurements on natural waters are difficult to interpret; therefore the 00E uses calculated redox conditions of -0.3 volts (and lower) in the draft EA, based on three arguments:
a) The coexistence of titano-magnetite with ferrous secondary iron-bearing
- - - - - -,,~
4 i
5 phases such as pyrite,,and the lack of naturally occurring ferric fron-bearing phases such as hematite; b) limited occurrences of sulfide-ions coexisting with sulfate ions, and methane coexisting with carbon dioxide; and, c) data from rock / water interaction experiments. With resp.ect to (a) and (b), the NRC considers that neither observable mineral assemblages and/or redox couples are sufficient to indicate that site redox conditions are chemically reducing and not chemically oxidizing (see detailed comment 6-33). With respect to (c), the NRC considers that these particular experimental results are not an adequate basis for suggesting that site redox conditions are as reducing as -0.3 volts, or are not chemically oxidizing (see detailed comment 6-33).
Concerning point (2), the DOE assumes that the redox conditions will reduce virtually all redox-sensitive radior.uclides to their least soluable and most sorptive state. However, it cannot be assumed that all redox sensitive
~
elements will be in chemical equilibrium within the system (Stumm, 1966, Lindberg and Runnels, 198?, Hostettler, 1984).
Therefore, even if redox conditions are established, it does not follow that redox-sensitive radionuclides will be reduced to their least mobile state.
- Further, experiments show that several redox-sensitive radionuclides exist in their more oxidized state under conditions of -0.3 volts and lower (Kelmers,1984, and Meyer, et al., 1984).
(See detailed comments 6-28 and 6-33).
For the Hanford site, geochemical conditions play an important role in site performance and the DOE has found favorably for all favorable and cotentially adverse guidelines. Assumed reducing conditions provide either the basis or support for each. favorable finding.
However, existing data appear insufficient either to support an unambiguous evaluation of site conditions and reactions or to support the assumption that the conditions are chemically reactive and that radionuclides will be present in their least mobile state.
The staff suggests that the DOE reconsider the data on redox conditions and reactions and reevaluate the findings on the related conditions under geochemical _ guideline 960.4-2-2 (conditions and processes at the site shall permit compliance with requirement for radioactive releases).
(See aise detailed comments 6-1 and 6-25 through 6-33).
COMMENT #4 Tectonic Stability Guidelines on Tectonics 10 CFR 960.4-2-7(a),(b),(c)(3),(c)(6),(d) and 960.5-2-11(a); Geohydrology (960.4-2-1(a),(b)(1) and (4)(11); and Rock Characteristics 960.4-2-3(a).
The draft EA presents a generally favorable view of the tectonic setting and possible effects of tectonics on waste isolation.
The NRC considers this view to be inadequately supported by the data and analyses in the draft EA, because a number of factors relevant to assessing tectonic stability appear to receive little consideration.
For purposes of discussion, these factors are grouped
6 into three topics:
favits in and near the reference repository location; recent fault activity; and potential for future fault activity.
Evidence suggesting that faults exist in and near the reference repository location, located in the Cold Creek syncline, include the presence of tectonic breccia, seismic reflection data anomalies and aeromagnetic map lineaments (see detailed comments 2-5, 3-11, and 6-41).
The presence of faults in the Cold Creek syncline would be consistent with the occurrence of major faults in the Vantage syncline area (an analog to the Cold Creek syncline, see detailed comment 3-13).
Faults related to the Cle Elum Wallula (CLEW) zone (a 40 kilometer-wide deformation belt, draft EA, page 3-52) may be present near the 4
reference repository location (detailed comment 6-41).
The DOE's preliminary conclusion that the reference repository location is located away from known or suspected faults (draft EA, pages 3-79, 6-129, 6-136, 6-214) does not adequately reflect the information noted above.
Existing evidence suggests recent fault movement in the reference repository location area.
Such fault movement, in the NRC's opinion, is expressed by hundreds of microearthouakes (up to magnitude 3.8) throughout the Pasco Basin including about sixty within 5 km of the reference repository location and ten with epicenters within the reference repository location boundaries (detailed comment 2-5).
An extension of the 115 to 140 km-long Rattlesnake-Wallula lineament (RAW), the part of CLEW that the NRC considers capable of an earthouake magnitude 6.5M, can be oostulated to pass a mile from the reference 3
repository location (see detailed comment 6-41).
Recent seismic activity appears to have occurred along the trace of the RAW and its projected north-western extension (see detailed comment 6-41).
The DOE's preliminary conclusion that "tectonically active faults do not appear to be present in the reference repository location" (draft EA, page 6-210) does not adequately reflect the information noted above.
An important factor in assessing future faulting activity for the Hanford site is the high hori: ental stress calculated from in situ measurements at depth in and near the reference repository location (see detailed comment 3-14).
The NRC considers that the high stress is resulting from the ongoing north-south compression (draft EA, page 2-18). Although the 00E considers that micreearthquakes are relieving minor amounts of stress (draft EA, oage 2-18),
the NRC considers that the stress is not necessarily being substantially relieved by microearthquakes and may be relieved by a moderate to large earthquake (detailed comment 2-5).
The DOE's preliminary conclusion that the long-term, low-average deformation rate indicates that tectonic processes such as faulting will not adversely affect waste isolation for 10,000 years after closure (draft EA, page 6-127) does not adequately reflect the information noted above.
The inadequate documentation regarding faults, fault activity, and future.
faulting activity in and near the reference repository location may have a significant impact on the bases of a number of 00E findings; these include:
tectonics conditions:
960.4-2-7(a), (b), (c)(3), (c)(6), (d) and 960.5-2-11(a).
Faults and active faulting may affect groundwater travel caths,
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travel times, and flow directions (see detailed comment 6-49 and gechydrology
]
conditions 960.4-2-1(b)(1) and 4(11)). Active faulting may also affect rock characteristics condition 960.4-2-3(a).
The NRC suggests that the DOE re-examine ana document information regarding faults, faulting and future fault activity presented above and re-evaluate its position on tectonic stability as applied to the siting guidelines. The 00E should then consider re-examining the tectonics and related guideline findings and either change or better support those findings.
COMMENT #5 Natural Resources Guidelines on Natural Resources 10 CFR 960-2-8-1 For qualifying condition 960.4-2-8-1(a), the 00E has not adequately documented available information on hydrocarbon resource potential such as: traps below or within synclines, and close proximity of anticlines to the reference recository location.
The draft EA implies that any potential for natural resources in the immediate vicinity of the reference repository location is low, because the repository location is in the Cold Creek syncline and is away from anticlines that form the traps for natural gas (draft EA, page 6-142).
Exploration in the Saddle Mountains has indicated that natural gas is present below the basalts (draft EA, page 6-187).
The deep (greater than 12,000 ft)
Shell Oil Company well, at Saddle Mountains 26km (16 miles) north of the reference repository location (draft EA, page 6-139), is the closest commercial exploratory drilling.
The exploration target is below the basalt.
The American Association of Petroleum Geologists newsletter, " Explorer",
(Shirley, Nov. 1984) indicates exploration activity on the Columbia Plateau is increasing due to rapid advancements in magnetotelluric methods capable of detecting deep structure ceneath the basalts. Magnetotelluric results show that the anticlines and synclines in the basalts do not reflect the structures beneath the basalts (RHO-BW-ST-19P). Hence, gas reservoirs below the basalts may be found under synclines in the basalts, as well as under anticlines.
The presence of hycrocaroon traps below the Cold Creek syncline may be indicated by the presence of methane (natural gas) in groundwater samples from the Cohassett flow, in the Cold Creek syncline (draft EA, page 6-187).
The EA states, on page 6-139, that the Yakima Ridge (3 kilometers (2 miles) west of the reference repository location) is the nearest anticlinal ridge to the reference repository location.
However, Yakima Ridge anticline is postulated by the DOE to exist buried (draft EA, page 3-51) within a half mile southeast of the reference repository location.
The DOE's assessment, as presented in the draft EA, does not consider possible kinds of natural gas traps other than anticlines, such as:
faults (detailed
8 j
comment 6-41 and 3-11) and feeder dikes which may be buried beneath the repository area (Ice Harbor dike, Pasco, U.S.G.S., 1979).
Based on the-indications cited above, we consider that the DOE has incompletely documented the finding and support of the qualifying condition (Section 960.4-2-8-1(a)). Another finding that is impacted by consideration of this information is potentially adverse condition 960.4-2-8-1(c)(1).
The NRC suggests that in the final EA, the DOE document consideration of the above information on hydrocarbon potential in the geologic setting of the Hanford site, and reconsider the findings for guideline conditions 960.-4-2-8-1(a) and 960.4-2-8-1(c)(1) and consider changing or better supporting them.
COMMENT #6 Thickness of Host Rock Guidelines on Rock Characteristics 10 CFR 960.5-2-9(b)(1),(b)(2), and (c)(1),
The draft EA states that favorable condition 960.5-2-0 (b)(1) is present.
This favorable condition deals with the host rock being sufficiently thick and sufficiently laterally extensive to allow significant flexibility in selecting the depth, configuration, and location of the underground facility. Although the data presented in the draft EA indicate that-the preferred candidate horizon (Cohassett Flow) thickness exceeds the 21-meter minimum thickness criterion stated on page 6-154, the discussion on pages 6-153 to 6-157 appears to be misleading because of the following reasons.
(1) Table 6-13 summarizes the statistical results of calculated thickness values of the dense interior of the Cohassett flow. Thickness values based on. regional and site specific boring data are presented for the dense interior below the flow top and the dense interior below the vesicular zone (DIBVZ). None of the thickness values presented in Table 6-13 for the dense interior below the vesicular zone exceeds twice the minimum thickness criterion.
Therefore, in stating that the Cohassett flow provides more than twice the minimum thickness (21 meters or 70 feet) necessary to construct the repository, the draft EA assumes that the entire dense interior is suitable for repository construction.
- However, Long and WCC (1984) page II-19, states that "the repository panel area would always be sited in the dense interior below the internal vesicular zone." Long and WCC (1984) also states that the vesicular zone is characterized by rock strength at least 35 to 65 percent lower than that of the underlying dense interior.
Rock support requirements depend in part on the rock strength.
Rock support evaluations in section 6.3.3.2.4 are based on the characteristics of the dense interior excluding the vesicular zone.
It is recognized in the draft EA on page 6-157 that greater'than minimal support may be required even for the openings in the DIBVZ.
Therefore, it must be expected that extensive maintenance and 1
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9 4
support may be r_equired for openings in the vesicular zone.
If calculations for support and maintenance requirements are based on properties of DIBVZ alone, it is inappropriate to take credit for the entire thickness of the dense interiem (2) The draft EA takes credit for the ability to exercise the " option to l
select from three other candidate horizons (Rocky Coulee, McCoy Canyon, j
and Umtanum flows)." Because of this option, the draft EA states that there may be "fui:her flexibility" in selecting a host rock horizon at depth. This does not seem to be reasonable, especially since page 6-157, paragraph 3, states that "...these flows do not appear to have sufficient 3
j minimum thickness..."
(3) An additional consideration in assessing flexibility for an underground facility location is the potential for significant thickness changes in the Cohassett flow within the reference repository location.
The draft EA states.(page 6-155), that the thickness data collected from boreholes in or near the RRL more closely represent the thickness of the host rock than does the regional data.
Regional data for the Cohassett flow presented in Table 6-11 indicate that the thickness of the dense interior below the
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l vesicular zone ranges from 19.8 m to 48.2 m.
Therefore, the potential for lateral variation in thickness exists.
It should be noted that such i
thickness variations were encountered in the Umtanum flow during the RRL-2 i
drilling. Thus, the potential for limited flexibility in the location and configuration of the repository should be recognized.
Host rock thickness is a significant element in the DOE Siting Guidelines 960.5-2-9(b)(1) and 960.5-2-9(c)(1) and may also affect the severity of rock support problems, as outlined in section 6.3.3.2.4, concerning 00E Siting Guideline 960.5-2-9(b)(2), which deals with minimal support requirements.
The final EA should provide a discussion about whether construction within the vesicular zone will be necessary.
If credit is taken for the entire dense interior in evaluating 00E Siting Guidelines 960.5-2-9(b)(1)-and 960.5-2-9(c)(1), modification of section 6.3.3.2.4 should be considered in the final EA so as to include a discussion on the additional support requirements for openings in the vesicular zone.
If credit is not to be taken for the thickness of the vesicular zone, a reevaluation of the craft EA statement that sufficient flexibility exists in selecting the depth, configuration and location of the underground facility should be considered (see detailed comment 6-37).
COMMENT #7 i :
Shaft Construction Guideline on Rock Characteristics 10 CFR 960.5-2-9(c)(2)
The conclusion regarding the DOE Siting _ Guideline.960.5-2-9 (c)(2), page 6-172, states that the need for engineering measures beyond reasonably available l
.2---
9 10 technology is not expected in the construction of repository shafts and underground facilities. - However, we consider that the evidence in the draf t EA does not support the DOE's conclusion regarding this potentially adverse condition.
In section 6.3.3.2.6.1 (Shaft construction), page 6-172, the EA states that it is viable to use the blind-hole drilling method for shaf t construction.
Justification for this claim is based upon (1) geotechnical information derived from ongoing studies, (2) an extensive and ongoing (small-diameter) drilling program, and (3) experience gained from other blind hole drilling projects.
The above claim is questioned for two reasons:
(1) Geotechnical information and experience gained at Hanford from the small diameter drilling program are not directly applicable to situations likely to be encountered in large diameter shaft drilling.
Granted, the same geological and hydrological conditions will be encountered when drilling boreholes and shafts, however, their effect on shaft stability differ considerably.
A 00E-sponsored document states that it is difficult to predict how the walls of a shaft will react based on information gathered during drilling of small diameter boreholes (see Morrison-Knudsen (1985), in detailed comment 6-65).
(2) The case histories presented in Table 6-20 on page 6-174 do not support the position on the feasibility of blind-hole drilling large diameter shafts, especially the 4.6 meter diameter operational shafts, with reasonably available technology.
None of the case histories had drilling constraints closely resembling those present at Hanford.
Important differences were:
(a) shaft diameter; (b) shaft length; and (c) geologic conditions (see detailed comment 6 - 7 *. ).
The recent study by Morrison-Knudsen (1985) identifies potential geologic hazards and corresponding remedial actions associated with drilling large diameter shafts at the Hanford site.
Problems in drilling full size snafts at Hanford (e.g., equipment failure, high stress condition, spalling condition, and mud loss) may be more difficult to deal with than what is presented in the draft EA.
Based on the discussion above, we suggest that 00E revise statements made in the draft EA concerning,the applicability of past drilling experience to large shaft drilling under ths specific conditi.ons at Hanford and reasess the conclusion on Siting Guideline 960.5-2-9(c)(2).
COMMENT #8 Waste Packace Lifetime The draft EA Executive Summary states, "The lifetime of waste packages at the reference repository locations is estimated to exceed 6000 years" (page 16).
11 Probability curves for the life of a typical waste container are provided in Figure 6-16 (page 6-244).
Section 6.4.2.3.3 (page 6-242, second paragraph) states that "The probability that a typical container will fail in less than 1,000 years is estimated to be close to zero.
The mean and standard deviation of container lifetime are estimated to be 6,100 and 600 years, respectively."
Further, a conservative approach is claimed in the draft EA's preliminary system assessment (56.4.2.1 Scope and Objectives, page 6-227; 56.4.2.3 Subsystem Performance Assessment, page 6-232 and 57.1.2, page 7-3) The NRC considers that the degree of certainty implied in the above statements is well beyond what can be supported by the data and analysis presented in the draft EA.
Several factors which tend to limit the container life have not been adequately accounted for in the draft EA.
Examples are:
1.
The oxidizing environment curing repository operation and after closure.
(See geochemistry major comment #3 and detailed comment 6-25).
2.
Localized corrosion as a waste package failure mode.
(See detailed comments 6-89).
3.
The effect of the packing on corrosion of the overpack material. (See detailed comment 6-94).
4.
The effect which instability of packing may have on the migration of radionuclides through the packing material (s6.4.2.3.3, page 6-248).
(See detailed comment 6-94).
The draft EA acknowledges (in page 6-242, last paragraph) that the corrosion analysis considers only generalized corrosion and that other container failure modes, such as pitting, hydrogen embrittlement and environment-assisted cracking, will be considered in a future analysis.
It further states that "It is possible that, in localized areas, corrosion may proceed at a relatively higher rate by such means." and that "... conservatism has been built into the present analysis in a number of ways:
o The container is assumed to fail when 7.5 centimeters (3 inches) of the wall thickness has corroced.
o The factor of limited oxygen supply available in the waste package subsystem has not been considered.
o The corrosion calculation did not take credit for the corrosion resistance provided by the oxide film formed in the air-steam environment."
l Also, "In addition, credit was not taken for the added containment time i
potentially provided by the zircaloy cladding of the spent fuel" (draft EA, j
page 6-284).
l i
12 The NRC considers that _the degree of conservatism claimed by the 00E to be built into the analysis through these factors is questionable for the following reasons:
o The container failure criterion stated above appears to correspond to axisymmetric yield for a wall thickness of 0.8 cm (i.e. 8.3 cm -
7.5 cm ).
However, the container will normally fail prior to this by non-axisymmetric elastic buckling (see detailed comment 6-86 for a more in depth discussion).
o No data or analyses are provided to show that availability of dissolved oxygen limits maximum depth of corrosion.
It appears at least equally plausible to assume that the amounts present dissolved oxygen and radiolytic peroxide are more than adequate for localized corrosion stress corrosion cracking and that the rates of these processes are limited by other factors.
o No data have been presented in the draft EA, or elsewhere, to support the possible formation of a significantly protective oxide film in an air-steam environment in the repository.
The staff suggests that the draft EA might be revised to more fully express the uncertainties in estimated waste package lifetime.
The DOE should then consider qualifying:
- 1) conclusions such as those cited in the first paragraph of this comment and 2) the descriptive material in Figure 16, page 6-244.
COMMENT #9 Comparative Evaluation of Sites Against Guidelines on Surface Flooding In assessing the guidelines relating to surface water flooding (960.5-2-8(c) and 960.5-2-10(b)(2)) the DOE appears to be inconsistent among the nine sites.
The 00E correctly concludes that at two sites (Deaf Smith and Swisher) the repository facilities are not subject to surface water flooding while at the other seven sites they are. The sites that are subject to flooding would have to be flood protected in varying degrees through the use of engineering measures. At four of those sites (Davis Canyon, Lavender, Cypress Creek, and Vacherie) the DOE concludes that because flood protection would have to be provided the adverse condition (960.5-2-8(c)) is present and the favorable condition (960.5-2-10(b)(2)) is not. At.the remaining three sites (Hanford, Yucca Mountain, and Richton) the 00E concludes that since. flood protection could be provided, through engineering measures, the adverse condition is not present and the favorable condition is.
The seven sites susceptible to surface flooding have not been treated equitably.
We suggest that the DOE decide whether credit for flood protection through engineering measures be considered in applying guidelines 960.5-2-8(c) and j
960.5-2-10(b)(2) and then implement the decision consistently. We note that engineering measures, if properly designed and implemented, can be used to protect almost any site from almost any flood. Thus, a decision to allow
13 credit for such flood protection may amount to eliminating the differeitiation between sites with respect to these guidelines.
COMMENT # 10 Comparative Evaluation of Sites The draft EA's describe in Chapter 7 and Appendix B the relative weights given to post-closure and pre-closure guidelines. As required by the guidelines, the DOE gave greater weight to post-closure guidelines (i.e., from 51% to 85% in applying the so-called utility estimation method).
However, the staff notes that the spread of site ratings on individual guidelines (see, for example, Tables B-2 and B-3) is distinctly different between the post-closure and pre-closure analyses.
The spread of ratings on pre-closure guidelines is much greater than it is for cost-closure guidelines.
The result of this wider spread is to have pre-closure guidelines dominate the overall ranking, notwithstanding the greater weight given to post-closure guidelines.
It appears as if the ratings might be relative in nature as opposed to being an assessment of sites on an absolute scale.
If ratings are indeed relative in nature, then inconsistent treatment of post-closure and pre-closure ratings may be interpreted as effectively going counter to the requirement that post-closure guidelines be assigned greater weight in site comparison.
The staff recommends that the description of the rating methods in the draft EA be expanded to explain the reason for the wider spread on pre-closure ratings and, in general, to describe more specifically the method of assigning ratings on individual factors.
14 Major Comments References Caggiano, J.A., and 0.W. Duncan, " Preliminary Interpretation of the Tectonic Stability of tne Reference Repository Location, Cold Creek Syncline, Hanford Site," RHO-BW-ST-19P, Rockwell Hanford Operations, March 1983.
DOE (U.S. Department of Energy), " Site Characterizations Report for the Basalt Waste Isolation Project", 00E/RL 82-3, 1982.
Early, T.O., G.K. Jacobs, D.R. Drewes, and R.C. Routson, " Geochemical Controls on Radioruclide Release from a Nuclear Waste Repository in Basalt:
Estimated Solubilities for Selected Elements", RHO-BW-ST-39, Rockwell Hanford Operations, 1982.
Early, T.O., G.K. Jacobs, and 0.R. Drewes, " Geochemical Controls on Radiouclide Releases from a Nuclear Waste Repository in Basalt:
Estimated Solubilities for Selected Elements," in " Geochemical Behavior of Disposed Radioactive Waste",
ACS Symposium Series 146, pp. 147-165, 1984.
Hostettler, J.D., " Electrode Electrons, Aqueous Electrons, and Redox Potentials in Natural Waters," American Journal of Science, Vol 284, p. 734-759, June, 1984 Kelmers, A.D., " Review and Assessment of Radonuclide Sorotion Information for the Basalt Waste Isolation Projects Site (1979 through May 1983)"
NUREG/CR-3763, ORNL/TM-9157 Oak Ridge National Laboratory 1984 Lindberg, R.O., and 0.0. Runnells, " Ground Water Reactions: An Analysis of Equilibrium State Applied to Eh Measurements and Geochemical Modeling,"
Science, Vol 225, pp. 925-927, (August 31), 1984.
Long, P.E., " Repository Horizon Identification Report, Vol. 1 and 2",
50-EWI-TY-001, Woodward-Clyde Consultants for Rockwell Hanford Operations, 1984.
Meyer, R.E., W.D. Arnold, and F.I. Case, " Valence Ef fects on the Sorption of Nuclides on Rocks and Minerals", NUREG/CR-3389, ORNL-5978, 1984 Morrison-Knudsen, Co., Inc., "Large Shaf t Development Study," S0-BWI-ER-007, Rockwell Hanford Operations, 1984.
RHO-BW-ST-19P, see Caggiano, 1983.
- Shirley, K., "Magnetotellurics Offers New Looks:
Columbia Plateau Activity Booms," American Association of Petroleum Geologists Explorer, pp.1, 6, 7,15, November 1984.
Stumm, W., " Redox Potential As An Environmental Parameter: Conceptual Significance And Operational Limitaions," in Advances In Water Pollution Research," Vol 1, pp. 283-308, 1966.
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15 Swanson, D.A. and R.T-Heiz, " Bedrock Geologic Map of the Vent System for the Ice Harbor Member of the Saddle Mountains Basalt, Ice Harbor Dam - Basin City Area, Southeast Washington," U.S.G.S., Open File Report 79-292, 1979.
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I EXECUTIVE
SUMMARY
COMMENTS E-1 i
Section 3, The site, page 10, paragraoh 4 The first sentence in this paragraph states that there are "no threatened or endangered animals and plants...known to occur at the site." The second sentence states "However, the bald eagle (an endangered species) and the peregrine falcon (a threatened species) have been sighted at the Hanford Site."
The fact that both these species have been documented to be winter visitors to the A-H site (Landeen, D. S. and R. M. Mitchell, 1981) indicates that they do 4
occur onsite.
i These same two statements are also found in the following sections /pages:
3-111; 3.4.2.5, page 3-103; 5.2.1.3.1, page 5-43; 6.2.1.6.11, page 6-37.
The 1
statement that there are no federally endangered or threatened species onsite 4
is also made in the folicwing sections /pages:
2.3.8.2, page 2-71; pages 5-i, i
5-11; 6.2.1.6.10, page 6-34; 6.2.1.6.11, page 6-35; 7.3.2.1.1, page 7-78.
It is suggested that the final EA clarify the apparent inconsistency perhaps by indicating that as far as is known, neither species nests onsite.
E-2 Section 5, Regional and local effects of repository devel.opment, page 14, caraoraan 2 This paragraph provides an explanation of the types of transportation effects from increased commuter traffic and the hauling of supplies and radioactive waste. The second sentence states that radiological risks result from routine waste shipments; there is no mention of radiological risk from transportation accidents.
It is suggested that the final EA include an assessment of both routine and transportation accidents effects and that this assessment be cited in the Executive Summary.
E-3 Section 6.2, Summary of site evaluations against the costclosure guidelines, page 15, caragraon 5 The draft EA states that " Estimates of ground-water travel time from existing data yield a median value of approximately 80,000 years.
Although there are many uncertainties in travel time calculations, there is no reason to believe on the basis of current information, that the ground water travel time is not well in excess of 10,000 years." Numerous problems co* exist with respect to i
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2 travel time calculations for the Hanford site.
These include:
- 1) problems with the applicability of previously published travel time estimates; 2) problems with the transmissivity data base and manipulation of those data for model input; 3) problems with the hydraulic gradient data base and the manipulation of those data for model input; 4) problems with the effective thickness data base and the manipulation of those data for model input; 5) problems with the theoretical basis of the travel time models presented in the draf t EA; 6) problems with the presentation of the results of the travel time models; and 7) problems with the definition of the orientation and length of the flow path from the disturbed zone to the accessible environment. All of 1
these problems create reasonable doubt as to whether the travel times are "well in excess of 10,000 years," as the 00E claims. As discussed in detailed comment 6-101, reasonable alternative analyses of the existing data can be performed which suggest that ground-water travel time along oaths of likely and significant travel may be substantially less than the 30,000 years claimed by the CCE.
E-4 Section 6.2, Summary of site evaluations against the costelosure guidelines, pages 15 to 16, caragraphs 4, 5 and 6 The data on Hanford Site redox condition do not support an evaluation that "...
the reference repository location has chemically reducing conditions that will promote precipitation and will maintain radionuclides in their least mobile state."
In fact, present redox conditions have yet to be established as either '
chemically reducing or chemically oxidizing (Early, et al.,1984).
Further, according to Lindberg and Runnels (1984), Meyer, et al. (1984),
Kelmers (1984), and others, the presence of reducing conditions alone does not mean that redox sensitive radionuclides will be present in the system as reduced species.
The assumption that the reaction kinetics and the available reduction capacity of tne system will be such that radionuclices will be reduced to their least mobile (low solubility, high sorption) state, would tend to underestimate radianculide releases.
(See detailed comments 6-1 and 6-33.)
i i
3 4
Executive Summary References Early, T. O., G. K. Jacobs, and D. R. Drewes, " Geochemical Controls on Radionuclide Releases from a Nuclear Waste Repository in Basalt:
Estimated Solubilities for Selected Elements," In " Geochemical Behavior of Otsposal Radioactive Waste," ACS Symposium Series 146., pp. 147-165, 1984 Kelmers, A.D., " Review and Assessment of Radionuclide Sorption Information for the Basalt Waste Isolation Project Site, (1979 through May 1983),"
i NUREG/CR-3763, ORNL/TM-9157, Oak Ridge National Laboratory, 1984.
Landeen, D. S. and R. N. Mitchell, " Site Ecology and Radiological Descriptions for the Basait Waste Isolation Project Site Characterization Report," RH0-1530,
- p. 20, Rockwell Hanford Operations,1981.
Lindberg, R.O., and 0.0. Runnels, " Ground Water Redox Reactions:
An Analysis of Ecuilibrium State Apolied to Eh Measurements and Geochemical Modeling,"
Science, Vol 225, pp. 925-927, ( August 11) 1984.
Meyer, R.E., W.O. Arnold, and F.I. Case, " Valence Effects on the Sorption of Nuclides on Rocks and Minerals," NUREG/CR-3389, ORNL-5978, Oak Ridge National Laboratory, 1984.
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4 CHAPTER I COMMENTS 1-1 Section 1.1.1, Engineered barriers, oage 1-2, paragraoh 3 2
The draft EA states that engineered barriers "... will not be relied on to compensate for major deficiencies in the natural barriers." (Emphasis added.)
In concurring in the DOE siting guidelines, the Commission was concerned that 00E may use engineered barriers to compensate for any deficiency in the geologic setting, not just " major" deficiencies. As a result, DOE revised.its guidelines to state, "... engineered barriers are not relied upon to compensate for deficiencies in the geologic media" (10CFR960.3-1-5).
The staff recommends that the word " major" be deleted from the EA's discussion of deficiencies for which engineered barriers may compensate. This revision would make the discussion consistent with the Commission's understanding of how the guideline will be applied.
a 1-2 Section 1.2.3.1, Basalt lava in the Pasco Basin. Washington, eage 1-11, paragraoh 1/ bullet 4 The data concerning changes in ground-water chemistry and mineral stability do not support a conclusive evaluation that "The likely geochemical reactions between the basalt rock, ground water and the materials that would be imolaced
" are all favorable for "... long-term isolation."
For example, based on (inconclusive) theoretical calculations of redox conditions and in tne absence of data on the recucing capacity of tne basalt / water system or the kinetics of redox reactions, it is assumed that radionuclides are released in their least soluble, most sorptive state (see detailed comment 6-30). Also, observed transformation of backfill / packing / fracture-filling clays to albite suggests tna centonite is reacting to yield a typical low grade metamorphic assemblage that includes illite (see detailed comment 6-27).
This transformation assemblage to illite has less sorptive capacity than the original backfill / packing / fracture-filling clays (see detailed comment 6-32). Assumed redox conditions influence radionuclide solubility and sorption, and cannister containment (see detailed comment 6-28).
Further, reported production of hydrogen and organic polymers similar to polyethylene in experiments involving Hanford site ground-water / gamma radiolysis, could affect waste package stability and radionuclide transport respectively (see detailed comment 6-1).
Thus, assuming l
that all likely geochemical reactions are favorable to long-term isolation, biases radionuclide release and transport estimates in favor of high transport retardation and low release l
l 5
1-3 Section 1.2.4, Nominations and recommendations of site for characterization, page 1-14, paragraph 1 The draf t EA states that the guidelines (10 CFR Part 960.3) require 00E to implement a seven part decision process in selecting sites for nomination and characterization. The guidelines present a six part, not a seven part, decision process (10CFR960.3-2-2-1 through 960.3-2-2-3).
The seventh decision point--consider the sites according to their order of preference--would be made after 00E nominates five sites and after the final EA's have been issued (see 10CFR960.3-2-3).
The staff does not object to sites being ordered in the EA according to 00E's preference. However, the EA could acknowledge that the guidelines do not require it to document how 00E orders the nominated sites.
1-4 Section 1.3.2.2. Distinct differences among the geohydrologic settings and host rocks, page 1-17, paragraph 4 It is stated that ground water drainage within the Pasco Basin is to the Columbia River or its tributaries. This is correct in a regional sense given that the Pasco Basin is fully encompassed by the large drainage basin of the Columbia (see draft EA, page 2-19).
However, the areal patterns of local recharge and discharge within the Pasco Basin are poorly understood at present.
An improved understanding of these phenomena is essential to support gechydrologic modeling studies over a range of scales including the Pasco Basin and the Cold Creek syncline.
The current, preliminary state of knowledge regarding recharge and discharge patterns might be presented in the final EA.
6 l
4 1
CHAPTER 2 COMMENTS 4
2-1 Section 2.1.1. Regional geology, eage 2-5, caragraoh 1 The fracture abundances may be understated due to vertical core borings in an environment of dominant vertical jointing.
Fracture abundances are part of establishing a data base for assessments related to gechyarnlogy, rock characteristics, and geochemistry.
It is suggested the final EA recognize the limitations of the data on jointing fractures resulting from a lack of angle cores.
2-2 Section 2.1.1. Recional ceolecy. cage 2-5. caracraoh 1 The draft EA states that dominant secondary minerals include pyrite.
According to Ames (1980), Teague (1980), Long and Davidson (1981) and Benson and Teague (1979 and 1982), pyrite is a minor secondary mineral.
The availability of fe~rrous mineral phases to interact with groundwater and the kinetics of redox reactions, are key to determining the reducing potential of the basalt / rock 1
system, and the capacity of the system to consume oxygen after closure.
In addition, some radionuclides, while not readily reduced in groundwater, can be reduced on the surface of fresh ferrous minerals (Bondietti, 1979, and Meyer, et al., 1984).
An overestimate of the quantity and availability of pyrite could lead to false assumations concerning future redox conditions, and an overestimate of retardation for those radionuclides affected by the reducing capacity of the rock and not the water (i.e., technetium and neptunium).
2-3 General comment on seismicity cresented in chaoters 2 and 3. Figures:
2-9, page 2-14; 2-10, oage 2-16; 3-20, oace 3-55; 3-25, cage 3-56 Various magnitude cut-offs, depth cut-offs, and data omissions on the figures listed above lead to difficulty in understanding the seismicity of the Hanford site region. The 8km depth cut-off in Figure 2-9 is inconsistent with the 4km depth cut-off in Figures 3-24 and 3-25.
The lower limit for magnitudes of shallow events of Figure 2-10 is unspecified. A well-known large micro-earthquake swarm near Wooded Island on the Columbia River at about 46.50'N and 119.25'W is not on Figure 2-10.
The recorded seismicity is a major part of the information needed to evaluate ground motion in the geologic setting.
Cigure 3-25 on page 3-56 shows six microearthquake epicenters in the reference repository location but data supplied by the University of Washington slows ten microearthquakes with coordinates that plot within the reference repository i
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location. A comprehensive figure with all earthquakes since 1969 is suggested to clarify recent seismicity.
2-4 Section 2.1.1.3, Seismicity, oage 2-15. Daragraoh 2 This section of the draft EA states the following:
" Deep seismicity generally takes place in a seemingly random pattern, associated neither with known j
geologic structures or areas of shallow seismicity." The implication of the above quote is that seismicity is not associated with structure. Correlations of earthquakes with tectonic processes and features (e.g., faults) may impact assessments of waste containment, regional groundwater flow, and future ground motion.
i Seismicity most commonly indicates fault movement. The draft EA has statements on page 6-132, paragraoh 2, page 6-136, caragraoh 3 and cage 6-212, paragrach 5 which appear to show agreement with the concept that seismicity is associated with fault rupture.
Focal mechanism solutions can be applied to larger seismic events (independent of mapped alignments) to interpret the type of fault movement. A suggested revision to this section of the draft EA is to consider that apparent random seismicity is likely related to fault ractures even when clear map alignments do not generally appear on previously identified structures.
2-5 Section 2.1.2, Tectonics, oage 2-15, caragraoh 4 This section of the draft EA states that the pasco Basin and Columbia Plateau have been deforming at low average rates of strain since the Miocene.
Five bullets in this section provide the bases for this view.
NRC has the following concerns about this position:
- 1) the importance of average deformation rates since the Miocene to tectonic assessments is cuestionable; and 2) information exists that suggests tne' deformation may be higner anc nas occurred episodically.
The basic premise that deformation has been at low rates when averaged over approximately 15 million years may not be significant.
The importance of long-term average tectonic activity to short-term contemporary and near-future episodic activity rates has not been established.
Consideration of estimated ranges of deformation rates during the Quaternary would be applicable to the siting guidelines.
The following discussion pertains to supporting bases, bullet number one, on page 2-15 of the draft EA.
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8 Structural elevations of basalts and other units in the anticlines of Rattlesnake Hills and the Saddle Mountains have been used to support initiation of deformation in Miocene time for the Yakima Fold Belt (RH0-BW-ST-19p).
The initiation of deformation may have been later than 14.5 to 10.5 million years ago, and'this is recognized in document RHO-BW-ST-19P.
The deformation of Umtanum Ridge-Gable Mountain-Gable Butte structure, 2 miles north of the present repository site, appears more recent than Miocene.
Deformation of Umtanum Ridge reportedly began in Saddle Mountain time (RHO-64I-ST-4), which is more recent than that of the Rattlesnake and Saddle Mountain structures. However, other data suggests that Umtanum Ridge-Gable Mountain - Gable Butte structure did not significantly deform until even more recently than Saddle Mountain time.
For ecample, the location of a late Pliocene channel of the ancestral Columbia River (Figure 3-20, page 3-41),
seems to indicate that the Umtanum Ridge-Gable Mountain-Gable Butte structure had not developed sufficiently at that time to affect the river channel.
Much of the structural growth of the Umtanum Ridge-Gable Mountain-Gable Butte structure may be late Pliocene to Recent and this is compatible with the apparent late Pliocene to early Pleistocere initiation of Manashtash Ridge to the northwest (RHO-BWI-ST-4).
In addition, Umtanum Ridge-Gable Mountain-Gable Butte structure appears to be still actively growing, as expressed by surface fault offsets that are about 12,000 years old, and two recorded tilts of the Rosa Canal within the last 50 years, reco-tedly due to anticlinal growth of the Umtanum Ridge (Brown, 1968, page 40).
The draft EA states that average uplift rates (vertical strain rates) were approximately 40 to 80 meters per million years from 14.5 to 10.5 million years ago on anticlinal folds.
Vertical uplif t is only one component of the total deformation.
The deformation in the Yakima fold belt includes both the vertical uplift components and the horizontal component of thrust or reverse faulting. Thrust faults are mapped along the strike of many folds in the Yakima Fold Belt (RHO-BWI-ST-4).
In the Saddle Mountains structure alone there are over 2,500 meters (in places up to 3,000 meters) of displacement on thrust faults (Reidel, 1984).
For the Saddle Mountains, the horizontal component of the fault displacement may be several times the vertical displacement of casalts by the folding / faulting process.
The following discussion pertains to supporting bases, bullet number two, on page 2-18 of the draft EA.
The draft EA indicates that there is a low average strain rate in the Pasco Basin partly because few earthquakes have been felt in the area and most historical earthquakes have occurred outside the margins of the Pasco Basin.
Consideration of only the felt earthquakes to support the low average strain l
i rate in the Pasco Basin makes use of only part of the information.
Hundreds of microearthquakes have been recorded in the Pasco Basin since 1969, including ten with epicenters in the boundaries of the reference repository location and L
9 about sixty within 5 km of the reference repository location which are rot considered " felt." All seisnic data, including both felt earthquakes ard those recorded only instrumentally, should be used to estimate strain rate ranges for the Pasco Basin based on seismic data.
The following discussion pertains to the supporting basis, bullet number three, on page 2-18.
Part of the basis in the draft EA for long-te a low average deformation is geodetic data. Geodetic data for only a few -ears (less than about 15) for a region is of uncertain value in assessing str.in rates.
For example, rapeated leveling surveys.in the area of the May 2, 1983 Coalinga, California ea thquake showed that except for defornation from fluid withdrawal, most deformation from 1960 to 1983 occurred during the earthquake (Stein,1983).
If the Coalinga earthquake did not occur, geodetic data would show no significant defornation.
Geodetic data and earthquake potential may not have a_ reliable correlation.
Another examcle is the 1977, San Juan, Argentina, earthquake.
In the a rea of this earthquake, geodetic leveling data indicated a total vertical char.ge of only 6 cm between 1938 and 1976 in the axis of the causative anticline.
Between 1976 and 1978, a drastic rate change occurred, over 1.0 meters of vertical change was recognir.ed. Most of the change is assumed to have occurred during the 1977 earthquake ( Volpont, et al.,1978).
Extrapolation of present day surface deformation can yield estimated sr. rain rates which can be orders of magnitude less than the actual strain ratt, if the period of time geodetic surveying is short compared to the seismic cycle (or recurrence interval for earthquakes).
The limits of surveying equipment add uncertainty to the deformation rites.
The reasured rates are near the limits of detection (RHO-BW-ST-19P).
The instability of surveying monuments has been a problem (RHO-BW-ST-19P).
In summary, the instrumental measurements of deformation are inconclusive.
The following discussion pertains to the supporting basis, bullet number four, on page 2-18 of the draft EA.
This part of the draft EA states that instrumental earthquake data for eastern Washington indicates minor stress release as microearthquakes.
In situ stress measurements indicate stress butidup to a considerable level (Kim and Haimson, i
1982), and discing of basalt cores also indicates the presence of unreleased horizontal stress (NRC, 1983, Figure A-12).
This existing high stress indicates microearthquakes are not relieving potentially significant major stres: accumulations and it remains possible for a moderate to large rarthquake to eccur.
This part of the draft EA indicates earthquakes are not manifestations of stress relief along mapped or inferred faults.
Focal mechanism solutions of earthquakes indicate that the north-south nearly horizontal compressions that
10 formed the Yakime Folt Belt are still on going (page 2-18, bullet 4).
These horizontal compressional stresses may result in thrust or reverse fault movements which do not show epicenter map alignments and may not be on mapped faults. Malone, et al., 1975, studied earthquake swarms in the Yakima Fold Belt and associated these events with thrust or reverse fault planes rupturing.
Faults can be inferred by the occurrence of a seismic event.
Data recorded since 1969 show hundreds of microearthquakes in the Pasco Basin.
These microearthquakes are considered to be an integral part of the Quaternary record.
Small fault ruptures can occur on segments of larger faults.
Microearthquake swarms occur in several locations in the Pasco Basin and provide evidence of current episodic non-uniform deformation.
It is suggested that this section of the draft EA be revised to include consideration of:
a) the importance of determining average deformation rates since the Miocene; b) uncertainties about the timing of deformation in the Yakima Fold belt; c) hori: ental strain rates; d) the limitations of geodetic data; and e) the microearthquakes in terms of small Quaternary fault ruptures in the subsurface, or other likely explanations for the seismicity.
1 2-6 Section 2.1.4, Regional ground-water hydrology, pages 2-24 tnrough 2-26 Thediscussioninparagraph2ofpage2-24refersthFigures2-15and2-16.
These figures depict three-dimensional (3-0) perspective. views of regional potentiometric surfaces. The perscective views lack the' locations, number and distribution of data points. Accordingly, distances of-inter-point extrapolation are unknown and the representativeness of the 3-D views cannot readily be determined.
It was stated in paragraph 2 on page 2-24 that surface trends and attitudes of the regional potentiometric surfaces'are similar to those of regional bedrock maps. Three-O perspective views of the latter are not shown.
It is possible to quantify the similarity or dissimilarity of sucn maps by suotracting structure contour surfaces from the potentiometric surfaces to obtain residual maps. Correlation coefficients may also be obtained.
Regional, trends are important to develop an understanding o'f the hydrogeologic conceptual model governing large-scale ground-water flow and radionuclide transport.
It would be useful to quantitatively know how closely the potentiom'etric surfaces are reflected by formational structural trends.
The inclusion of residual maps in the draft'EA, as described above,-is recommended.
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11 1
2-7 Section 2.2.1.1, Identification of site localities, Figure 2-21, cace 2-43 and Ficure 2-22, page 2-45 Figu.res 2-21 and 2-22. indicate that portions of the DOE's cu' rent reference repository location were previously eliminated from the candidate area during site screening. These figures show stippled areas designated on the legends as: " Areas of the Pasco Basin Eliminated during Site Screening." The reference repository location (not drawn on either Figure) encompasses areas i
shown on the figures as having been eliminated as a site locality during site screening.
It is suggested that the final EA be revised to reconcile the discrecancy noted above by an explanation or by redrawing tne boundaries of the reference repository location.
2-3 Section 2.2.1.2, Identification and ranking of candidate sites, oage 2-46, paragraph 5 The discgss' ion in this paragraph indicates the importance of geophysical lineaments to the selection of a' candidate site within the Cold Creek Syncline.
However, a map dapicting these lineaments is not presented in the draft EA.
Given the scarcity of rock -exposures in the; syncline, the geophysical
,. lineaments, as probable manifestations of geologic structures, provide data
- about the approximate' spatial distribution :of such structures.
Information about possible structures within the casalts is of significance in planning large-scale hydrologic test's. An important aspecf of these tests is tne evaluation of hydrologic councary effects whien may be caused by structural j
and/or stratigraphic discontinuities.
In addition, if large-scale vertical structures exist within the syncline they may provide preferential pathways for radionuclide transport to tne accessible environment.
Information about geoi6gic structures is necessary to help guide investigations of: site-hydrogeology,' seismology and geomechanics. Given the above, the lack of'a geophysical lineament map from the draf t EA is a significant omission.
The only relevant map is Figure 3-23 on page 3-46, wnich does not show features within the Cold Creek Syncline. An example of the type of map which-could be included in the final EA would be Figure 8-8 of ST-14 (Myers,1981).
- E 2-9 l
Section 2.2.3, Identification of a preferred candidate horizon, page 2-57, paragrapn 4 u
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12 The last sentence in this paragraph is unclear with regard to which hydrologic properties of the candidate horizons were used for comparative purposes.
It is implied that porosity and dispersivity data may have been used for this purpose. To date only two field tests have been performed (Gelhar, 1982; Leonhart, et al., 1984) on-site within flow tops for the purpose of obtaining values of dispersivity and effective thickness. Of the two tests, only one appears to have been performed within the flow top of a candidate horizon, the McCoy Canyon flow (see detailed comment 3-24). Given this fact, it is unclear how other horizons coeld have been compared on the basis of measured values of dispersivity and effective *hickness. All aspects of the decision logic used to select a preferred candidate horizon are of significance and might be clarified in the final.EA.
2-10 Section 2.2.3, Identification of a preferred candidate horizon, cage 2-59, caracraohs 2 and 3 The discussion of travel time and cumulative activity of iodine-129 values presented on this page is unclear. The cumulative activity values are not compatible with the travel times presented for the respective candidate horizons. Assuming equal effective thickness values and a constant source term for all four candidate horizcns, one would expect the lowest total flow and the lowest cumulative iodine-129 activities to be associated with the highest travel times.
This is true for the Cohassett but does not follow appropriately for the other candidate horizons.
The McCoy Canyon flow would be expected to have the highest cumulative activity because it has the shortest calculated travel time.
This is not the case; the Umtanum has the highest cumulative activity. This apparent inconsistency should be resolved, perhaps by presenting a more complete discussion of the values presented in this section.
2-11 Section 2.2.3.2. Acolication of excert judgement to the candidate horizons, page 2-63, caragraon 2 The following phrases appear in the draft EA regarding the potential for vertical confinement of radionuclides:
"However, the Cohassett flow still provided vertical confinement that, based on preliminary modeling results, prevented significant contamination of the overlying, relatively high permeability zones....." and " Vertical confinement thus appeared adequate." These statements are important to the development of the DOE's preferred hydrogeologic conceptual model as described in paragraph 2 on page 3-93.
j Although the first paragraph of this section points out that the assessment was 1
mainly deductive, it should be emphasized that reliable estimates of vertical 1
13
~
hydraulic conductivity have yet to be obtained for the relatively dense basalt interiors.
Therefore, it was not possible to directly compare the vertical isolation potential of the candidate horizor s.on the basis of hydrologic test data. Given the importance of vertical isolation of radicnuclides, the means by which the four candidate horizons were compared on this basis might appropriately be presented in the final EA.
2-12 Section 2.3, Summary of the evaluation of the potentially acceptable site within the gechydrologic setting, page 2-64. paragraph 1 The DOE states that before sites can be considered for nomination, the COE must ensure that " --- no obvious disqualifying conditions exist at any of the potentially-acceptable site."
(Emphasis added.)
The stafff considers it inaporooriate for the DOE to apply only " obvious" disqualfiying conditions when the DOE has committed, in the guidelines, to apply at least ten. The staff recommends that the sentence in question be revised to read, "It is prudent to ensure that at this step in the siting process none of the disqualifying conditions, identified in Appendix III of the guidelines, exist at any of the potentially acceptable sites." The same revision should also be considered for the last sentence of the same paragraph.
2-13 Section 2.3.8.2 Summary of the environmental cuality disoualifier analysis.
page 2-71, caragraoh 1 This summary section states that "The three primary factors that indicate this disqualifying condition is not present at the reference repository location are (1)..., (2) the absence of any federally recognized threatened and endangered species at the reference repository location, and (3)....
Therefore, the evidence supports a finding that the reference repository location is not disqualified on the basis of tnat evidence and is not likely to be disqualified (Level 2)."
As pointed out in detailed comment E-1, it is a well documented fact that the bald eagle (an endangered species) and the peregrine falcon (a threatened species) are winter visitors to the reference repository location.
It is suggested that this condition be reevaluated for endangered species, l
14 Chacter 2 References Ames, L.L., "Hanford Basalt Flow Mineralogy," PNL-2847, Pacific Northwest Laboratories, 1980.
Benson, L.V., and L.S.Teague, "A Study of Rock-Water-Nuclear-Waste Interactions in the Pasco Basin, Washington.
Part 1:
Distributions and Compositions of Secondary and Primary Mineral Phases in Basalts of the Pasco Basin, Washington," LBL-9677, Lawrence Berkeley Laboratory, 1979.
Benson, L.V., and L.S. Teague, " Diagenesis of Basalts from the Pasco Basin, Washington - I.
Distribution and Composition of Secondary Mineral Phases,"
Journal of Sedimentary petrology, Vol 52, No 2. pp. 595-613, 1922.
Bondietti, E.A., " Geologic Migration Potentials of Technetium-99 and Neptunium-237," Science, Vol 203, pp. 1337-1340, March 30, 1979.
Brown, R. "A Study of Reported Faulting in the Pasco Basin," EWIL-662, Pacific Northwest Lab., 1968.
Caggiano, J.A., and 0.W. Duncan, " Preliminary Interpretation of the Tectonic Stability of the Reference Recository Location, Cold Creek Syncline, Hanford Site," RHO-BW-ST-19P, Rockwell Hanford Operations, March 1983.
- Gelhar, L., " Analysis of Two-well Tracer Tests With a Pulse Input,"
'H0-BW-CR-131 P, Rockwell Hanford Operations, 1982.
Kim, K.,.and B.C. Haimson, "In Situ Stress Management at a Candidate Recository i
Horizon," RH0-BW-SA-357, Rockwell Hanford Operations, 1982.
Leonhart, L. S. et al., " Analysis and Interprecation of a Recirculating Tracer Experiment Performed on a Deep Basalt Flow Top," RHO-BW-SA-300 P, Rockwell Hanford Operations, 1984.
Long, P.E. and N.J. Davidson, " Lithology of the Grande Ronde Basalt With Emphais on th Untanum and McCay Canyon Flows," in "Suosurf ace Geology of the 2
Cold Creek Syncline", Edited by C.W. Myers and S.N. Price, RHO-BWI-ST-14, Rockwell Hanford Operations, 1981.
Malone, S.O., G.H. Rothe, S.W. Smith, " Detail s of Microearthquake Swarms in the Columbia Basin, Washington," Bull. Seism. Soc. Am., Vol 65, pp. 855-864, 1975.
Meyer, R.E., W.O. Arnold, and F.I. Case, " Valence Effect on the Sorption of l
Nuclides on Rocks and Minerals," NUREG/CR-3389, ORNL-5978, Oak Ridge National Laboratory, 1984.
f l
15 Myers, C.W., " Bedrock Structure of the Cold Creek Syncline Area,"
in " Subsurface Geology of the Cold Creek Syncline," RHO-BWI-ST-14, Rockwell Hanford Operations, 1981.
Myers, C.W., and S.M. Price, " Geologic Studies of the Columbia Plateau: A Status Review," RHO-BWI-ST-4, Rockwell Hanford Operations, October,1979.
NRC, "Oraft Site Characterization Analysis of the Site Characterization Report for the BWIP," NUREG-0960, Nuclear Regulatory Commission, Washington, D.C.,
1983.
Reidel, S.P., "The Saddle Mountains:
The Evolution of An Anticline in the Yakima Fold Belt," American Journal Science, Vol 284., No 8, pp. 942-978, 1984.
. RHO-BW-ST-19P, See Caggiano, 1983.
RHO-BWI-ST-4, See Myers, 1979.
Stein, R.S., " Reverse-Slip on a Buried Fault during the 2 May 1983, Colainga Earthquake:
Evidence from Geodetic Level Changes," Calif. Dept. Conservation,
- 01. Mines and Geol., Spec. Publ. 66, pp. 151-164, 1983.
Teague, L.S., " Secondary Minerals Found in Cores DC 2A1 and DC 2A2 Taken from the Grande Ronde Formation, Pasco Basin, Washington," LSL-10387, Lawrence Berkeley Laboratory,1980.
Volponi, F., A. Robles, and M.Quiroga, "El Terremoto de Cauceter del 23 de Noviembre de 1977:
Informe de la Universidad Nacional de San Juan (Argentina),
Instituto Sismologico Zonda," 81 p.
(The Caucete ( Argentina) Earthouake of November 23, 1977:
Information Circular of the National University of San Juan, Zonde Seismological Institute), 1978.
16
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CHAPTER 3 COMMENTS 3-1 Section 3.2, Geologic conditions, pages 3-1 through 3-56 There is no discussion of mineral resources in this section. Also, there is no discussion of mineral resources in Chapters 4 and 5.
All information on mineral resources in this draft EA is presented in detail in Section 6.3.1.8,
" Human interference (natural resources)" which covers siting guideline 960.4-2-8-1.
Mineral resources may have implications for the socioeconomic analysis as well as the performance of the recository system after closure.
It is suggested that the appropriate information on mineral resources be placed in Chapters 3, 4 and 5 to make each of these Chapters more complete.
3-2 4
Section 3.2.2, Stratigraphy, page 3-10, paragraohs 2 and 3 There is no presentation in the draft EA of the results of the geophysical.
surveys and how they are input to stratigraphy. Geophysics is commonly used to distinguish structure or the continuity of stratigraphy.
Establishing the data base on stratigraphy impacts assessments of: selecting the repository location, groundwater travel, response of units to tectonic processes, and geochemistry.
The geophysical methods used for developing " stratigraphy" are simply listed on page 3-10.
It is suggested the draft EA be modified to describe, even in summary form, the results of the geophysical surveys and how they were input into selection of the reference repository location.
3-3 Section 3.2.2.1, Grande Ronde basalt, page 3-13, figure 3-8 This figure, labeled " Geologic cross section through the reference repository location" is too generalized.
Less than one-half of the length of the cross section is controlled with borehole data and is uncontrolled north of OC-4 and southwest of RRL-6. Also, the cross section does not indicate known structures in the area.
Cochran (1982) has described faults which lie in the area of the cross section which are not indicated in Figure 3-8.
Understanding stratigraphic continuity necessitates adequate consideration of structural features and is important to assessing repository location selection.
e
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9 17 It is suggested that better-controlled geologic cross sections which show i
structure be presented in the craft EA.
3-4 Section 3.2.2.1.2, McCoy Canyon flow, oage 3-20, paragraph 2 There is an inconsistency within the draft EA'on the minimum thickness of the McCoy Canyon flow. This paragraph of the draft EA indicates that the McCoy Canyon flow is a minimum of 112 feet thick but the executive summary (page 7, paragraph -3) indicates this flow is at least 130 feet thick.
The McCoy Canyon flow is one of four flows identified as candidate host horizons for the repository.
The continuity and thickness of these four flows affects assessments of relative suitability for the repository.
It is suggested that the inconsistency detailed above be reconciled.
3-5 Section 3.2.2.1.3, Cohassett flow, page 3-24, paragraph 2 If as stated in the draft EA, "the colonnade-entablature tiers are not readily correlated from borehole to borehole in the reference repository location,"
then the flow may have significant unassessed heterogenetties.
Lateral heterogeneities in the area of the reference repository location may impact design of the repository and groundwater flow.
It is suggested this section of the EA be modified to more completely assess the uncertainties of the internal stratigraphy in the Cohassett flow by specifying the boreholes and logs showing lack of correlation and evaluating the differences among them.
3 1 1
Section 3.2.2.1.3, Cohassett flow, page 3-24, caragraon 2 A description is presented on this page of the Cohassett flow and the continuous vesicular zone which occurs in this flow.
There is little documentation in the draft EA about where the repository would be placed with respect to'the vesicular zone.
This question is important to the draft EA with respect to computed ground-water travel times.
The importance of this question is lessened in the draft EA~since in its most recent analyses (Clifton et al.
(1984)), the 00E does not take credit for travel time through the dense interior of the Cohassett flow.
This could be-a significant question if the DOE decides to take travel time credit through the dense interior of the Cohassett.
1
18 3-7 Section 3.2.2.2, Wanapum basalt, page 3-28, paragraoh 3 In this section the Wanapum Basalt is described as thickest in the central area of Cold Creek syncline and thinning over Rattlesnake mountain and the Umtanum Ridge-Gable Mountain structures. This does not agree with other data.
Isopach maps for this basalt are in Reidel and others (1980).
These maps indicate the thickest sections may lie below Rattlesnake Mountain, the southeast Rattlesnake Hills adjacent to Rattlesnake Mountain, the southeastern extension of the Yakima Ridge structure and in the Snively Basin area.
As tectonic and structural interpretations, such as of age, amount and timing of folding and related faulting. are partly based on descriptions of basalt thicknesses, seismic hazard evaluations may be affected.
It is suggested that other available data be considered in the final EA, including thickness changes where thrust faulting associated with Yakima fold structures has occurred.
3-8 Section 3.2.3.2, Umtanum Ridge, Gable Mountain structure, cage 3-48, paracraoh 4 continued from eage 3-47 This section. indicates that Umtanum fault, which is part of a south dipping imbricate thrust fault system of about three faults, dies out about 11 kilometers (7 miles) east of Priest Rapids Dam. This is based on " judgment" which assumes that the structural relief from folding results in thrust fault displacement (i.e., thrusting is assumed to be secondary to folding).
This assumption does not consider information which could significantly affect assessments of the tectonic processes near the reference repository location.
Washington Public Power Sup y System states tne following in volume 25 of the WNP-2, FSAR, 1981: "We +
f the Columbia River, the Umtanum Ridge and Hanson Creek faults farth orth have the spacing and geometry of an imbricate south dipping thrust zone of primary origin." The Umtanum faulting involves imoricate thrust fault processes.
Imbricate thrust faults typicaFly are associated with splays (Boyer and Elliott,1982).
It is possible that the Umtanum faults or associated splays, which although buried, continue east to the vicinity of the reference repository location.
The lateral extent of a thrust sheet may be controlled by stratigraphy and not' folding. On the basis of stratigraphy, individual thrust sheets are often correlated long distances (Boyer and Elliott, 1982).
The Hanford Site area is still undergoing N-S compression (p. 2-18).
In addition, high horizontal in situ stress conditions are evidenced in the area by hydrofracture test results (RHO-BW-ST-28P) and discing in borehole cores (RHO-BWI-ST-14).
Because of the ongoing N-S deformation and because thrust
i 4
19
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faults result from high horizontal compressional failure of rock, it is reasonable to conclude that the Hanford site is in an active fold belt where thrust faulting can be expected to continue.
It is also reasonable (see paragraph 2 above) in the absence of any specific information to the contrary, to assume that the Umtanum thrust faults or splays continue east to the reference repository location area. These projected south dipping faults could go above, through, or under the reference repository location and pose a potential earthquake hazard or may affect hydrological modeling.
It is suggested this section of the draft EA be revised to consider the information above to include an assessment of the seismic hazard to the reference repository location from projected thrust faults of Umtanum Ridge.
3-9 Section 3.2.3.2, Umtanum Ridge - Gable Mountain structure, oage 3-49, paragraoh 1 This part of the draft EA does not adequately consider alternative interpretations of data for what may be a significant Quaternary fault in terms of ground motion impacts on the reference repository location.
This paragraph indicates a long-term average displacement rate on an undesignated Gable
~4 Mountain fault of abou* 6 x 10 centimeters per year.
The actual maximum possible rate for any sear would be larger and more significant.
The fault rupture could have been a few events.
Analysis of the episodic nature of faulting is appropriate.
This cannot be achieved by reliance on an average for tectonic processes.
Due to the fact that the undesignated fault apoarently continues its trace at depth and is a few kilometers from the repository, a significant earthquake relative to the reference repository location could be associated with this fault.
It is suggested the draft EA name the undesignated fault referenced above based on common terminology (NUREG-0309) and the magnitude of earthquakes which could be generated be addressed.
3-10 Section 3.2.3.3, Cold Creek syncline, page 3-49, caragraoh 3 and oage 3-50, paragraoh 3, continued from page 3-49 This section of the draft EA indicates that the Cold Creek syncline is in an area of an intact volumes of basalt, excluding intraflow structures.
This is not consistent with the narrative portion of Myers (1981) report (RH0-BWI-ST-14) which qualifies the interpretation of basalt volumes by using the term "relatively intact." The NRC has documented evidence suggesting
1 20 structural discontinuities in the Cold Creek syncline and reference repository location (detailed comment 3-11).
Structural features is part of the data base for assessments on geohydrology and potential ground motion.
It is suggested this section of the EA be revised to qualify, explain and document the statement that the Cold Creek syncline is in an area of intact volumes of basalt.
3-11 Section 3.2.3.3, Cold Creek syncline, page 3-50, paragraph 1 This section of the draf t EA states the following: "Overall, the central and eastern portions of the Cold Creek Syncline, which includes the reference repository location, appear to be free of potentially adverse structures."
This statement does not agree with other published information.
Structural features are important to evaluations of groundwater flow and faulting.
As indicated in detailed comment 2-5, microearthquakes are likely small movements along subsurface faults. Since 1969 many (well over a hundred) microearthquakes have occurred in the central and eastern portions of the Cold Creek syncline, including ten with eoicenters in the boundries of the reference repository location.
It is not certain that the estimated, short, fault-rupture lengths during microearthquakes (Caggiano, 1982) are occurring on 4
short length faults.
The microearthquakes may be on major structures which have not yet been defined because monitoring has been done only since 1969.
The aeromagnetic interpretive map (RHO-BWI-ST-14) shows about five possible faults that are in the reference repository location boundaries and several others (acout five) in the immediate vicinity of the reference repository location.
The top of basalt contour map (RHO-BWI-ST-14) shows several (about seven) small possible fold structures tnat are in tne reference repository location boundaries.
It has been interpreted in RHO-BWI-ST-14 that the uppermost flows of the Saddle Mountains Basalt (i.e., the top of basalt) reflect some expression of the Grande Ronde Basalt flows (i.e., the repository candidate host rocks) and some small folds can be expected in the Cohassett flow.
Seismic-reflection surveys in the Cold Creek syncline located five anomalies, interpreted by Seismograph Service Corporation to be bedrock faulting (RHO-BWI-ST-14).
Several interpretations other than faulting have been l
hypothesized by Rockwell Hanfo'rd Operations and should be considered valid possibilities (RHO-BWI-ST-14).
Nevertheless, all Seismograph Service Corporation seismic anomalies were avoided in delineating potential repository sites (RH0-BWI-ST-14).
Recent seismic reflection reprocessing and interpretation by Emerald Exploration Consultants, Inc. identify possible faults within the boundaries of e wr
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21 the reference reposito y location (50-BWI-TI-177). One small anticlinal fold
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and one small synclinal fold were also interpreted within the boundaries of the reference repository location.
Each of these. folds is associated with a potential fault.
This raises the possibility that the previous (RH0-BWI-ST-14) approximately seven small interpreted fold structures that are in the boundaries of the reference repository location may be associated with faults.
Document SD-BWI-TI-177 entitled " Reprocessing and Interpretation Seismic Reflection Data Handford Site, Pasco Basin, South Central Washington" is not included in the draft EA references even though it was released on May 15, 1984. As with the faults and folds in document RHO-BWI-ST-14, the faults and folds in document 50-BWI-TI-177 have other possible interpretations that are also valid hypotheses.
However, the Emerald Exploration anomalies have not been avoided in delineating the reference repository location.
A major difficulty in conclusively identifying structures in the basalts of the Cold Creek Syncline is that the rock exposures are covered by sediments.
However, document SD-BWI-ER-005 detail.s an analog study area, the Vantage syncline.
There, rock exposures are accessible.
Observations in the Vantage synclinal area show direct evidence of faulting and folding. Although, the Vantage analog area is not without considerable uncertainty regarding applicability to the Cold Creek syncline, it seems likely that many of the folds and faults interpreted in and near the reference repository location exist.
Further evidence of potential faulting in and near the reference repository location includes the presence of " tectonic breccia" in all deep boreholes in the Cold Creek syncline, including the reference repository location (RHO-BWI-ST-14). Also, it is possible that the buried part of the eastern segment of the Yakima Ridge is faulted (detailed ccmment 6-41).
It is suggested that:
the EA be revised to remove the sentence (see paragraph 1 above) stating that the reference repository location and the central and eastern Cold Creek syncline appear free of potentially adverse structures; data from report 50-BWI-TI-177 on seismic reflection anomalies in the reference repository location be referenced in the EA; the data on anomalies and their relationship to structure in document RHO-BWI-ST-14 from each type of investigation be documented or referencec in discussions of potentially acverse structures; and information from the Vantage analog area (50-BWI-ER-005) should also be included.
3-12 Section 3.2.3.3, Cold Creek syncline, pace 3-50, continuing paragraph 1 This section of the draft EA states the following: "The structure of the top of basalt and the structure at deeper horizons within this area [ Cold Creek Syncline] are interpreted as being nearly flat lying with very gentle dips
22 toward the trough of the Cold Creek Syncline...".
Published information exists which indicates that the top of basalt is not nearly flat.
Report RHO-BWI-ST-14 shows about seven sma,ll possible fold structures that are in the reference repository location boundaries.
This report also interprets that the top of basalt reflects some expression of the structure of the repository host rock.
Report RHO-BWI-TI-177 has interpreted a small anticlinal and a synclinal fold in the top of basalt in the reference repository location.
Small folds in the basalt surfaces may have associated fractures or faults (detailed comment 2-5) and could affect groundwater flow and construction.
It is suggested this section of the EA be revised to recognize interpreted local folds on the basalt surface and at. repository depths.
3-13 Section 3.2.3.3. Structural analysis, cace 3-52. caracrach 2 This section of the draft EA states the following:
" Structural analysis of Yakima folds in the Pasco Basin area shows tnat little deformation, other than tectonic jointing, has taken place in the anticlinal crests, and that little or no deformation occurred in the syncline trough (Price, 1981)." The report by E. H. Price did not include synclines in the study areas.
Further, the draft EA does not consider other information relevant to deformation in syclines.
A recent, 00E-sponsored study of the Vantage area has been undertaken to determine the nature, and extent of tectonic breccias related to faulting and folding in a synclinal area. This area, unlike the buried Cold Creek syncline, has basalt exposures visible at the ground surface.
Evidence from this area suggests (is conclusive for the Vantage syncline) that synclines in the Yakima Fold Belt may have considerable deformation which could influence groundwater flow.
The Vantage study shows that tectonic breccias and fractures located to date are associated with major folds and faults mapped in the area (SD-BWI-ER-005).
Tectonic breccias have been found in all deep coreholes in tne Cold Creek syncline, including the reference repository location.
The term tectonic breccia doesn't define the tectonic process which formed the breccia.
Snearpa rock zones, such as breccia, shows rock displacement and can be considered indicative of faulting whether or not associated with folding.
The tectonic breccia shows deformation occurred in many places in the synclinal trough.
The Wooded Island and Coyote Rapids microearthquake swarms are in synclinal structures (see detailed comment 6-44).
This shows current structural deformation occurring in synclinal troughs.
t.
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23 h
L It is suggested this section of the draft EA be revised to include the evaluation of Vantage synclinal deformation, tectonic breccias, and microearthquake swarms.
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3-14 j
Section 3.2.3.8, Structural analysis, page 3-53, paragraph 1 For structural analysis, this section of the draft EA refers to in situ i
hydraulic stress measurement as defining the axes.of principal and least-compression. However, additional structural analysis could have been made using the ex,isting in situ stress data, q
This section lacks data specifying the ranges of the in situ stress measurements and there is no information in this section to show that relative i
to many other deep mines in the world the horizontal in situ stresses at the j
Hanford site are unusually high (Hoek & Brown.1980, EA pages 6-175 and 6-200, i
and RHO-B'4-ST-28P).
i l
By assessing the orientation and amount of stresses which may act to cause deformations, indications can be derived of the likelihood and types of structural features and orientations that may develop or be reactivated.
For a 1
more detailed discussion of deformation, see detailed comment 2-5.
4 It.is suggested that this section of the draft EA be revised to present data on in situ stress and consider more fully the applications of in situ stress i
orientations and magnitudes to structural analysis of the Hanford area.
1 i
3-15 Section 3.2.4. Seismicity of the reference recository location. page 3-54 paragraph 3, 4, and 5 I
This section of the draft EA describes three areas of swarm activity within 10 kilometers of tne reference repository location.
Two discrepancies appear to exist.
First, the four events that occurred in November 1969, described in Paragraph 3 as a swarm, were not located only at the southern boundary of the reference repository location.
Instead, they were located along a 1
north-ncrthwest, south-southeast trending zone that extends across about i
two-thirds of the central portion of the reference repository location to an epicenter about one mile south of the reference repository location.
Second, a cluster of earthquakes located astride the northern boundary of the reference 4
repository location that occurred between March 6, 1971 and August 17, 1971 are i
not discussed as a swarm.
The epicenters of these six events are located within an area of about one square mile in extent'and they have' focal depths j
i ranging from 6,5 to 8.0 kilometers.
The largest event was a magnitude 1.1.
1 1
24 Microearthquake swarms in the immediate vicinity of the underground facility could have adverse impacts.
For example, the larger events in a swarm could initiate rock bursts which could lead to collapse of openings and difficulties in waste emplacement or retrieval operations. Additionally, joints might open and joint fillings could be disturbed which could increase groundwater flow.
It is suggested that all areas of microearthquake swarm activity within 10 km of the reference repository location be described in this section of the final EA.
i 3-16 Section 3.3.1.3.5.' Flash fleed cotential within the reference recository location, page 3-67 paragraoh 2 i
Results of flood studies in the Cold Creek watershed (Skaggs and Walters, 1981) indicate that a potential for flooding of portions of the recository site exists. As proposed in the conceptual designs, it appears that several of the repository surface facilities will be placed in the Cold Creek floodplain.
Based on an examination of the Skaggs and Walters report, it appears that the magnitude of flooding on Cold Creek may be underestimated.
The Probable Maximum Flood (PMF) was estimated in the report to have a magnitude of 55,000 cubic feet per second (cfs) at the site where the drainage area is about 86 square miles.
Review of historic flood data for arid regions of Washington and Oregon with similar climates and weather patterns indicates that a flood of this magnitude has occurred on a stream with a drainage area of about 13 square miles, located less than 150 miles from the site.
Recognizing that the Cold Creek basin could have different flood producing
' characteristics than the stream which produced the historic maximum discharge, it is nevertheless important that tne PMF represent tne upper limit of flood potential'for a particular stream.
It appears that this upper limit has not been well-defined for Cold Creek.
Based on preliminary coservations, it appears that the most probable cause of underestimating the PMF is overestimating the time of concentration, resulting in lower flood peaks.
The presence of steep (>2*.) channel gradients upstream i
of the site indicates that Cold Creek channel velocities will likely be high and that the time of concentration (tc) may be considerably less than the te estimated in the report.
PMF peak flows should be re-examined, in light of the potential for reduced times of concentration.
In addition, maximum water levels will be increased as a result of increased l
PMF discharge and will also be increased by site location in the flood plain.
l The amount of increase in water level due to flood plain constriction has not been discussed in the draft EA.
Based on examination of the topography and cross-sections in the site area, it is likely that surface facilities may have
25
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to be placed on severa1 feet of fill to elevate important accesses and structures above maximum expected flood levels.
Constriction of flow area in the flood plain may increase the water levels. associated with major floods.
This increased level and its impact should be discussec.
Additionally, the flood analyses and the information provided on the proposed site conceptual design indicate that repository facilities may be exposed to a potential flood threat from Cold Creek.
Recognizing that definite locations and site grades have not been established for surface facilities, it appears that the requirements of Executive Order (E.O.) 11988, " Floodplain Management,"
have not been addressed.
This E.O. requires, among other considerations, that alternatives to siting in a floodplain (along with the hazards and impacts associated with those alterna.tives) be identified and evaluated.
Accordingly, a discussion of the precedures involved in this decision-making process should be provided and compliance with E.O. 11988 should be discussed in the draft EA.
Further, Table 6-2 (Page 6-30) indicates that floodplains would not be modified.
However, based on the flood analyses. it appears that portions of the floodplain'may need to me mcdified. This apparent inconsistency should be addressed.
3-17 Section 3.3.2 Groundwater, oage 3-79, paragraoh 2 The draft EA states that the ground water system can be characterized and modeled such that overall flow patterns roughly conform to bedrock dip. Data are not presented to support the statement that ground water flow conforms to bedrock dip. This concept is important to the EA from the standpoint of determining ground water flow directions.
Ground water flow does not have to follow bedrock dip. Ground-water flow is determined by hydraulic gradient.
Ground water flow cauld be perpendicular to the direction of becrack dip or can flow updip. This question could be resolved by either rewording this section of the EA or by presenting data to either support or refute this statement.
Also see detailed comment 2-6.
3-18 Section 3.3.2, Ground water, page 3-79, paragraoh 2 This section states that the geohydrology of the reference repository location appears to be most influenced by the following:
"A large contrast in hydraulic conductivity between flow tops and flow interiors.
This feature promotes lateral ground water movement in the flow tops (aquifers) and vertical flow across basalt flow interiors (aquitards). Actual flow directions depend on the hydraulic head distributions." These statements may not be pertinent to the large-scale ground-water flow in the basalts.
The distribution of vertical
9 26 hydraulic conductivity may vary significantly based on structural and other
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types of discontinuities in the basalt.
3-19 Section 3.3.2.1.1, Flow interiors, page 3-85, paragraphs 2 and 3 i
The draft EA states that the vertical hydraulic conductivity of basalt flow interiors at the Hanford site reference repository location is about the same order of magnitude as the horizontal hydraulic conductivity.
This conclusion is based on the results of one field test and two indirect analyses. The distribution of vertical hydraulic conductivity has been identified as a critical parameter in repository cerformance assessment.
Vertical hydraulic conductivity must be known to evaluate the potential for ground-water flow to
{
upper aquifers, including flow tops and interbeds.
The conclusion regarding the anisotropy ratio of hydraulic conductivity is not supported as explained l
below.
An initial field test of vertical hydraulic conductivity of a flow interior (Spane, et al., 1983) is cited by the DOE in this section.
Spane et al. (1983)
-10 reported a vertical hydraulic conductivity of "less than 10 meters per second" for the Rocky Coulee flow interior.
However, the NRC studies (Golder Associates, Inc., 1984) indicate that the test arrangement was not appropriate for the type of tests performed, and therefore there are substantial questions regarding tha usefulness of the test results.
Furthermore, alternative interpretations (e.g., Brown, 1984) of the test results are possible which could yield a vertical hydraulic conductivity as much as two orders of magnitude greater than the result citec in tne draft EA.
The draft EA cites two references which purportedly describe model-calculated and statistical indirect estimates of vertical to horizontal hydraulic conductivity anisotropy ratios.
One of the cited documents (00E, 1982) was apparently misreferenced, as the document contains no discussion of the 2:1 estimate of anisotropy which the draft EA attributes to the document.
The other document (Sagar and Runchal,1982) is a demonstration of statistical technique for analyzing the effects of fracture size and data uncertainties, based on fracture set orientation information gained from a rock sample taken from Gable Mountain.
The Sagar and Runchal (1982) document is based on assumptiens regarding fracture frequency, aperture and length, which appear to bear no relation to site specific data (Gordon, 1984).
In fact, Sagar and Runchal (1982) state that "the calculations... are intended as 'n illustrative example and not as a definitive statement on the hydraulic condut;ivity of the fractured basalt at Gable Mountain." Therefore, the cited anisotropy ratio of 3.5 to 1 derived by Sagar and Runchal (1982) should not be considered to apply, in general, to Hanford basalt flow interiors.
i
27 As discussed above, the draft EA has not supported its statement that the vertical hydraulic conductivity is of about the same order of magnitude as the horizontal hydraulic conductivity.
3-20 Section 3.3.2.1.1, Flow interiors, eage 3-86, paragraph 1 The draf t EA states that preliminary single hole tests have been conducted for evaluating the effects of drilling mud invasion on hydraulic conductivity estimates. Williams and Associates (1984) have noted that the well development procedures used during the hydraulic conductiv.ity evaluation were not the same as those as used on other boreholes or as documented in the COE test procedure reports. Therefore, the finding that drilling fluid would not have aaversely affected hydraulic tests of the deep basalts during single-hole tests has not been supported as of this date.
3-21 Section 3.3.2.1.1, Flow interiors, eage 3-86, caragraph 5 It is stated in this section that a localized fracture zone of 3 foot thickness
~#
1 was found to have a " hydraulic conductivity of 10 m/sec (10 ft/ day)."
According to Strait and Spane (1983), this zone is considered to be 6 feet
-4 thick, and is calculated to have a hydraulic conductivity of 5.2 x 10 m/sec (147 ft/ day).
The final EA should resolve this inconsistency.
3-22 Section 3.3.2.1.2, Use of geometric mean to describe hydraulic conductivities, page 3-88, caragraoh 4 In this section, the COE uses tne gecmetric mean of cata from several units of a given rock type (e.g., flow tops) as a measure of the average horizontal hydraulic conductivity of that rock type.
This may in some cases be a misleading representation of the properties of an average unit of a given rock type. The geometric mean of a set of hydraulic conductivities from different hydrostratigraphic units will be weighted towards the lowest values, compared to the arithmetic mean.
For horizontal groundwater flow, the geometric mean of a set of units of a certain rock type (e.g., flow tops) will not be f
representative of the average hydraulic conductivity of that set, unless each individual unit displays the same geometric mean as the geometric mean of all of the considered units, and as wide a variance in hydraulic conductivity within a unit as the variance between units.
Preliminary data (Stone, et al.,
1984) suggest snat the geometric means of transmissivity of the Umtanum flow top and the Conassett flow too, for examole, may differ oy almost two orcers of
28 4j l
f magnitude.
Individual units may not display as wide an internal variability as the variability between units.
In order to estimate the horizontal hydraulic conductivity of an " average" unit, it may be more appropriate to use a thickness-weighted arithmetic mean of the set of geometric means of hydraulic conductivities of individual units.
3-23 Section 3.3.2.1.2, Flow contacts and sedimentary interbeds, oage 3-88, paragraoh 5, and oage 3-89, continuing paragraph The draft EA states that " Geophysical log traces indicate that ground water movement is sometimes channeled along narrow intervals (less than or approximately one meter (3 feet)] as opposed to being averaged across the entire effective thickness of the flow top."
The draft EA goes on to state that local values of hydraulic conductivity may be higher than the " equivalent" hydraulic conductivity of the effective thickness of the flow too.
During
~
previous data reviews and discussion in workshops with Hanford personnel effective thickness had been defined as the portion of the test interval which has been deemed to supply the majority of the flow during tests.
Elsewhere in the draf t EA (e.g., page 6-266), " effective thickness" is defined as "the product of an assuned flow too effective corosity... and the mean aoparent thickness...".
This represents an inconsistency in the use of the phrase "ef fective thickne ss" throughout the draf t EA.
This inconsistency is significant because transmissivity, derived from hydrologic tests, is converted to hydraulic conductivity based on a determination of the effective test interval thickness. Hydraulic conductivity is an important parameter for determinations of travel time and hence performance assessment.
Therefore, the choice of values for " effective thickness" is critical and the language used should be made consistent.
This matter could be resolved by defining effective thickness and using the definition consistently throughout calculations of hydraulic conductivity and grouno water travel time in tne craf t EA.
i 3-24 Section 3.3.2.1.2, Flow contacts and sedimentary interbeds. oage 3-89, paragraoh 1 It is stated that two tracer tests have been conducted in the flow top of the l
McCoy Canyon flow. One of the supporting references given is Gelhar (1982).
l However, according to Gelhar (1982), page E-31, "The tested interval is about l
220 feet above the top of the Umtanum flow of the Grande Ronde Basalt." This I
places the test interval in the flow top of the unnamed Grande Ronde 9 unit which overlies the McCoy Canyon flow (see Cross,1983, OC-7/8, page 3 of 5).
l If both stated references are correct, then the paragraph should be changed to indicate that two separate units have been tested.
1
29 3-25 Section 3.3.2.1.3, Bedrock structures, oage 3-90, caragraoh 3 The draft EA states that "Hydrochemical data suggest that mineralized deep waters may be mixing vertically with more dilute, shallower ground waters along or near this feature." The feature referred to is the Cold Creek hydrologic barrier which is northwest of the reference repository location. The concept of vertical ground-water flow near the barrier is important to the EA with respect to assessment of ground-water flow directions and travel times.
Data supporting the concept expressed in the final EA should be presented or reft enced.
3-26 Section 3.4.2 Terrestrial and aquatic ecosystems, page 3-96 through 3-104 Figure 3-26 (page 3-59) shows Cold Creek running southeast through the Hanford Site and through the southwest sector of the reference repository location.
Approximately one-third of the Hanford site is drained by this system (Section 3.3.1.2).
Cold Creek will be the recipient of site runoff and construction-related contamination if construction practices fail to contain erosion, siltation, chemicals, etc. These materials may be carried via Cold Creek to the Yakima River and to the Columbia River.
A description of the Cold Creek biological and physical ecosystem on a seasonal basis would be helpful to determine whether impact is mitigated to insignificant levels.
Similarly, a description ad the biotic ecosystem of West Lake (the only natural pond within the site) would be useful in relation to potential impacts from site activities.
3-27 Section 3.4.2.7.5 Radiation exoosures, page 3-109 At the top of page 3-109, the statement is made tnat soil and vegetation assays taken from the Hanford Site environs have disclosed no discernable differences in the levels of radionuclide concentrations across the geographical area.
This statement apparently does not consider the radiological assay information in " Site Ecology and Radiological Descriptions for the Basalt Waste Isolation Project Site Characterization Report," (Landen and Mitchell,1981).
It is.
suggested that Section 3.4.2.7.5 consider the radiological assay information from this report.
3-28 Section 3.4.2.5 Threatened and encangerec saecies, oaces 3-103
~
30 This section notes that no federally recognized threatened or endangered species or their critical habitat are known to occur within the reference repository location.
The draft EA cites State, and FWS lists from 1980 to 1933 but does not show evidence that the DOE has formally contacted FWS under Section 7 of the Endangered Species Act for advice on the presence of species within the project area, including:
the reference repository location; the areas where roads and railroad spurs will be placed; the area where the pipeline will be placed that provides water from the Columbia River; the Columbia River; the Cold Creek watershed; and the Yakima River from the confluence of Cold Creek to its confluence with the Columbia River.
It is
~
suggested that the final EA state what contacts were made and whether impact areas outside the reference repository location were included.
3-29 Section 3.4.3, Meteorological conditions and air cuality, pages 3-109 to_3-116 i
Severe meteorological conditions are not evaluated.
Several severe meteorological phenomena can have an important influence on repository construction and operation, and transport of radioactive material to the site.
Among these are high winds, dust storms, fog, and snow and ice.
It is suggested that the frecuency and duration of these hazardous meteorological conditions be addressed in this section.
3-30 Section 3.4.3.5. Air cuality, eaces 3-114 second caragraoh 4
Insufficient information is presented in the draft EA to define air quality in i
the region. This information is necessary for the evaluation'of the 4
conclusions regarding air quality.
The assessment only refers to the Skagit/Hanford DES for current air quality conditions in the Columbia Basin.
It is suggested that a summary table of air quality in the Hanford area be presented in this assessment and compared to the standards presented in Table 3-11 (page 3-117).
4
31 Chaoter 3 References Boyer, S.E., and David Elliott, " Thrust Systems," American Association of Petroleum Geologists Bulletin, Vol 66, pp. 1196-1230, 1982.
Brown, A., " Review of 50-BWI-TI-136," enclosure to Letter #71, NRC Contract NRC-02-82-045, NRC Division of Waste Management File No. 3426.1/FINB7373, February 14, 1984.
Caggiano, J.A., " Development of Fault Parameters for Use in Risk Assessment Modeling in the Pasco Basin, Columbia Plateau, South-Central Washington -- A Preliminary Study," RH0-BW-SA-185o. Rockwell Hanford Ocerations, March 1982.
Chamness, MA., and T.L. Tolan, " Status Repor
,n the Tectonic Fracture and Breccia Study in the Vantage Area," S0-BWI-Eh
'5, Rockwell Hanford Operations.
September, 1983.
Clif ton, P., R. Arnett, and N. Kline, "Prelimin y Uncertainty Analysis, of Pre-waste-emplacement Groundwater Travel Times For a Proposed Repository in Basalt," S0-BWI-TA-013, Rockwell Hanford Operations,1984.
Cochran, M.P., " Geophysical Investigation of Eastern Yakima Ridge, South Central Wastington," RH0-BW-SA-260AP, Rockwell Hanford Operations, 1982.
Cross, R. W., " Deep Borehole Stratigraphic Correlation Charts and Structure Cross Sections," SD-BWI-OP-035, Rockwell Hanford Operations, 1983.
00E, " Site Characterization Report for the Basalt Waste Isolation Project,"
00E/RL-82-3, 1982.
I Emerald Exploration, "A Study of Reinterpretation of Seismic Reflection Data i
(Lines 3, 5, and 8)," 50-BWI-TI-177, Rockwell Hanford Operations, May,1984.
Gelhar, L. W., " Analysis of Two-Well Tracer Tests With a Pulse Input,"
RHO-BW-CR-131 P, Rockwell Hanford Operations, 1992.
Golder Associates, Inc., "BWIP Hydrogeology Occument Review," Letter #71, NRC contract No. NRC-02-82-045, NRC Division of Waste Management File No.
3426.1/FINB7373, February 14, 1984.
Gordon, M., " Review of Sagar and Runchal (1982), ' Permeability of Fractured Rock'," Enclosure to memorandum to M. Fliegel (NRC), NRC Division of Waste Management File No. 3101.2, October 24, 1984 Hoek, E. and Brown, E.T., " Underground Excavations in Rock," The Institution of Mining and Metallurgy, London, p. 100, September 1980.
w-
--w ae m
v wg-,
32 Landeen, O.S. and R.M. Mitchell, " Site Ecology and Radiological Descriptions for the Basalt Waste Isolation Project Site Characterization Report,"
RH0-CO-1530, Rockwell Hanford Operations, 1981.
4 Long, P.E., and Woodward-Clyde Consultants, " Repository Horizon Identification Report," Vols. I and 2, RHO-BWI-ST-28P, Rockwell Hanford Operations, 1984.
Meyers, C.W., and S.M. Price, " Subsurface Geology of the Cold Creek Syncline,"
RHO-BWI-ST-14, Rockwell Hanford Operations, July, 1981.
NRC, " Safety Evaluation Report Related to the Construction of Skagit/Hanford Nuclear Project, Units 1 and 2," NUREG-0309, Occket Nos. STN 50-522 and 50'-523, Supplement No. 3, December 1982.
Price, E.H., " Structural Geometry, Strain Distribution, and Tectonic Evolution of Umtanum Ridge at Priest Rapids, and a Comparison with Other Selected Localities within the Yakima Fold Structures, South Central Washington,"
RHO-BWI-SA-138. Rockwell Hanford Operations, 1982.
Reidel, S.P., R. K. Ledgerwood, C.W. Meyers, M.G. Jones, and R.D. Landon, " Rate of Deformation in the Pasco Basin during the Miocene as determined by distribution of Columbia River Basalt Flows," RHO-BWI-SA-29, Rockwell Hanford
~
Operations, 1980.
RHO-BW-ST-28P see Long, 1984.
RHO-BWI-ST-14 see Meyer, 1981.
Sagar. B. and A. Runchal, " permeability of Fractured Rock: Effects of Fracture Size and Data Uncertainties," Water Resources Research,18(2), April 1982.
50-BWI-TI-177 see Emerald Exploration, 1984.
50-BWI-ER-005 see Chamness, 1983.
i Skaggs, R.L. and Walters, W.H., " Flood Risk Analyses of Cold Creek Near the~
Hanford Site," RHO-BWI-C-120, Rockwell Hanford Operations, January, 1931.
Spane, F., P. Thorne, and W. Chapman-Riggsbee, "Results and Evaluation of Experimental Vertical Hydraulic Conductivity Testing at Boreholes DC-4 and OC-5," SD-BWI-TI-136, Rockwell Hanferd Operations, 1983.
Stone, R., et al., " Strategy and Preliminary Plans for Large-scale Hydraulic Stress Testing of Selected Hydrogeologic Units at the RRL-2 Location," Rockwell Hanford Operations,1984 Strait, S. and F. Spane, " Preliminary Results of Hydrologic Testing the Umtanum Basalt Fracture Zone at Borehole RRL-2," SD-BWI-TI-089, Rockwell Hanford Operations, 1983.
l
33 Williams and Associates, " Communication No. 84," Contract No. NRC-02-32-044, NRC Division of Waste Management File No. 3426.1/FINB-7372.
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34 i
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CHAPTER 4 COMMENTS l
4-1 Section 4.1.1.3.1, large-scale hydrologic stress tests, page 4-7, caragraoh 3 l
1 j
The term " vertical transmissivity" is used in this paragraph.
Transmissivity normally is defined to be hydraulic conductivity times the thickness of the j
aquifer unit; the term pertains to horizontal flow. No similar concept exists for vertical flow. Use of this term in the draft EA is confusing. Omission of this term from the paragraph would eliminate the problem, j
f l
4-2 Section 4.1.1.6.1, Construction, eage 4-12, caragraoh 2 j
i she draft EA states that the effectiveness of the cement grout seal will be examined directly using boreholes drilled through specially designed portholes l
i in the shaft casing.
This statement implies that the effectiveness of the j
grout seal depends entirely on the continuity of cement grout, and the grout continuity can be successfully tested through soecially designed portholes.
These implications do not seem reasonable.
l Firstly, the effectiveness of the grout seal is not a function of grout continuity alone.
It would also be influenced significantly by the integrity of grout bond With rock wall and shaft liner which would be affected by the presence of drilling mud cake.
Secondly, plans for testing the continuity of I
the grout and integrity of liner grout-rock band through the portholes may not provide a representative data base. As porthole testing confirms the grout I
characteristics at the site of the test only, porthole test locations could 3
introduce a large bias into the best results.
It is important that porthole j
testing occurs within and adjacent to aquifers and in areas of good and poor j
quality rock. The exclusion of testing in any of these areas may give an I
unrepresentative picture of the grout continuity and bond integrity.
Uncertainties associated with overall grout continuity and cond integrity will I
decrease with an increase in the number of porthole tests performed.
Each of these factors will contribute towards the making of an effective seal which is essential for inhibiting the flow of water into the working areas
{
during shaft break out.
Therefore, it is suggested that these factors be considered in the final EA.
4-3 i
i Section 4.1.2.5, Archaeological surveys, page 4-17
.. ~.
~.
i 1
L f
35 i
l i
- The discussion in this section omits reference to required consultation j
activities.
It is recommended that 00E include provision for consultation i
with the State Historic Preservation Officer and when appropriate, contact with the Keeper of the National Register of Historic Places and the Advisory Council on Historic Preservation to assure compliance with the National Historic Preservation Act of 1966 and 36 CFR 800.
4-4
^
Section 4.2.1.2.1 Surface-water imoacts, page 4-20, caragraph 4 It is stated tnat approximately twelve hydrologic stress tests discharging an average of 3.2 e 10' cubic meters of water would be acclied to the land surface through ponding or spraying.
It is.then predicted that this quantity of water "will increase plant vitality," "may increase the size and number of desert plants" and that "no adverse impact is expected" and "nonarid species are not expected to be established at these locations."
3 In Section 6.3.1.1.9 page 6-78 it is stated that the deep basalt groundwater has an electrical conductivity of 1,500 micromho per centimeter which is in the high salinity range for irrigation water.
Calculations show that 3.2 x 10' cubic meters of water with a conductivity of 1.500 micromho oer centimeter would contain 26.5 tons of salt.
Twelve such tests would involve 318 tons of salt. Therefore, the conclusion of "no adverse impact" would depend a lot on the size of the area and timing of the 12 tests, neither of which is specified in the draft EA.
It is suggested that 00E consider timing of hydrologic tests and quality of disposed drilling fluids.
l 4-5 j
Section 4.2.1.3.1.1. Terrestrial, cage 4-25, paracraon 3 It is stated that "More than half the plants within this area were destroyed l
and all the animals were disolaced during construction activities."
It is not clear why only aoout half tne piants were cestroyed.
In most cases tne species population will eventually be reduced by the number of individuals the lost l
habitat supported and will result in a permanent reduction in wildlife populations.
It is suggested that emphasis be placed on habitat loss and the i
i associated permanent reduction in wildlife population (Kroodsma, 1955).
i 4-6 j
Section 4.2.1.3.1.1, Terrestrial, cace 4-27, paragraoh 3
]
While it is mentioned that the Swainson's hawk and long-billed curlew both nest i
near the proposed exploratory shaft sites there is no discussion of the i
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36 possible affect of cons'tructing the shafts on these species.
Because these two species are candidates for the US FWS endangered or threatened list, it is suggested that an evaluation of the consequences of clearing and grading 8 hectares (20 acres) for constructing the shaf ts should be considered. This section mentions only two candidate endangered and threatened species while Section 5.2.1.3.1, page 5-43, paragraph 2 mentions a third, the ferruginous hawk.
It is suggested there be a consideration of including the ferruginous hawk in this section.
4-7 Section 4.2.1.3.1.2, Aquatic, eage 4-27 This section states that the majority of site characterization activities are not conducted in the vicinity of aquatic habitat.
It is suggested that impact of activities that will be conducted near aquatic habitat needs to be assessed to determine that mitigation is adequate.
Additionally, it is that suggested the impact of withdrawing 30 cfs of water (Section 4.2.1.2.1) from the Columbia River should be examined in relation to important fishery resources.
1 4-8 Section 4.2.1.3.2, Air quality impacts, page 4-33, second oaragraoh Insufficient meteorological data and/or assumptions are presented to review the determination of air quality impacts.
This section evaluates the ability of repository activities to meet national air quality standards. A description of the input meteorological data is given for annual average pollutant concentrations (page 4-32). Table 4-5 (page 4-33) presents potential increases in pollutant concentrations for annual average and 1-hour maximum conditions.
It is suggested that the input meteorological data used to obtain the 1-hour maximum values be provided. Also, it is suggested that the impact of background concentrations on both 1-hour maximum and annual average concentrations be presented.
4-9 Section 4.2.1.3.3, Noise, impacts page 4-34 The draft EA states that impacts of noise from the project on the general public are said to " meet the requirements of the Noise Control Act of 1972".
The Act addresses many noise-related issues and by itself does not establish limits on environmental noise for acceptable impact.
It is suggested that the statement should be replaced with more definitive statements that clearly illustrate the intended meaning of the Noise Control Act of 1972.
(Also see Section 5.2.1.3.3, page 5-44.)
4 37
~
4-10 Section 4.2.1.3.6 Radiolooical imoacts, oage 4-34 This section does not address release of radon-220, radon-222 and their radioactive decay products.
These are, however, mentioned on page 5-45, in the third paragraph of Section 5.2.1.3.6 Radiological Impacts, but no estimates of released quantities are provided.
The reference (00E, 1980) gives little information about the basis for the estimates, but it implies that it includes a concept that no radon will be released except during active mining and back-filling, contrary to experience at uranium mines.
In addition to continuing releases from the surfaces of the repository drifts and rooms, the stockpiled mined rock fragments will also continue to release radon.
It is not expected releases of naturally occurring radionuclides at any of the candidate sites would be significant in terms of doses approaching regulatory limits, unless radon releases are much greater than usual for such rock types.
However, a credible indication of the magnitude of~the releases can be obtained by monitoring the ventilation oathway during the site character 1:ation process.
l (Also see section 6.4.1, page 6-217).
I 4-11 Section 4.2.1.3.6, Radiological imcacts paces 4-34, and 4-35 The DOE considers two sources of radiation that originate from site characterization activities:
1.
tritium brought to the surface by the drilling; and 2.
radioactive tracers that would be used to determine effective porosity and dispersively.
The DOE then concludes, "No major radiological imoacts are anticipated due to site characterization activities."
The draft EA does not give a complete description of tne raciological environment at the Hanford Reservation.
Consequently the DOE's assessment of radiological impacts appears to be incomplete.
The draft EA does not note that the shallow depression within the reference repository location, called "U Pond" has received radioactive effluents since the beginning of the Manhattan Project (00E,1982). Additionally, five ditches or ponds, all within the reference repository location are used for the disposal of low-level radioactive wastes (W.C.C.,1981).
As a result of these discharges, soil, vegetation and near-surface groundwater within the reference rapository location have a higher concentration of radionuclides than the median concentration for the Hanford area (00E,1982 and W.C.C 1981).
w..
38 The draf t EA states that the tritium concentration in an unconfined aquifer at the exoloratory shaf t site is presently less than 2 picocuries per milliliter.
Other studies, however, show that groundwater beneath the reference repository location has tritium levels from 30 to more th'an 3000 picocuries per milliliter (W.C.C., 1981).
The final EA shoulc resolve the discrepancy between the trituim concentration reported in the draft EA and the concentration reported in W.C.C.,
1981.
The impacts of concucting site characterization in a contaminated area might also be considered.
For example, would any of the excavations or drilling exhume low-level radioactive wastes or bring contaminated groundwater to the surface?
?
____.__.____._..____j
39 4
.i i
Chaoter a References 3
j 00E, 1980, Final Environmental Impact Statement: Management of Commercially i
Generated Radioactive Waste," 00E/EIS-0046-F, Vol, I, p. 5.56.
1 i
00E, " Site Characterization Report for the Basalt Waste Isolation Project,"
00E/RL-82-3, pages 7.1-11, November, 1982.
i j
Kroodsma, Roger, "In my opinion... Assessing the loss of wildlife habitat in l
environmental impact statements," Wildlife Society Bulletin 13:82-87, 1985.
i W.C.C., " Study to Identify a Reference Repository Location for Nuclear Waste i
Repository on the Hanford Site," RHO-BWI-C-107 Volume I, Woodward-Clyde l
Consultants for Rocnwell Hanford Goerations, 1981.
i i
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?
1 r
k I
i i
1 4
1 4
i l
i l
5, I.
I j
i
40 CHAPTER 5 COMMENTS 5-1 Section 5-1, The recository, page 5-3, paragraoh 3 The draft EA states, "The current features of the two phase concept include...
a 35 year retrieval option period." The inclusion of the 35 year retrieval option period may cause additional problems in terms of room and emplacement borehole stability due to thermal induced fracturing.
The potentially adverse condition stated in 00E Siting Guideline 960.5-2-9(c)(4), although acknowledged to be present, will be further enhanced due to this increase in preclosure period.
It is suggested that the effects of the 35 year retrieval option l
period be discussed in the final EA.
~~ 5-2 Section 5.1.2.1, Surface facilities, oage 5-18, paragraph 4 Withdrawal of water from the Columbia River can adversely affect the to aquatic biota by means of entrainment and impingement.
The addition of two pumps in an existing pump station can increase the impact level of the existing facilities.
It is suggested that an assessment be made of the impact potential of water withdrawal on river biota.
5-3 Section 5.1.2.1.1, Ventilation--982 conceptual design, page 5-20, paragraph 2 Cooling towers dissipate dissolved solids called " drift." Orift can have adverse effects on the terrestrial environment depending on its chemical composition and quantity.
Therefore, if a cooling tower is utilized, the final EA mign: consicer tne potential impact of the crift on tne terrestrial environment.
5-4 Section 5.1.4.3, Waste container configuration and packing, page 5-38, paragraon 1 The draft EA states that the packing material around the waste containers is required to limit groundwater' intrusion and to reduce radionuclide release.
However, it is not possible to evaluate the performance of this packing material because its behavior under high temperature conditions is not
41 adequately presented in the draft EA.
Furthermore, the draft EA does not mention the temperature to be expected in the vicinity of the waste package.
This high temperature performance becomes important because Allen, et al.
(1983) show that at temperatures of 300 C, the basalt / bentonite packing material converts to iron and potasium rich smectites along with secondary silica, atbite and zeolites.
Further, experimental work by Couture and Seitz (1984) strongly suggests that water vapor causes rapid, apparently irreversible degradation of the swelling capacity of bentonite.
The resulting materials are likely to have a lower sorption capacity and reduced volume, both of which may influence radionuclide release rates (see detailed comments 6-25 and 6-27).
It is suggested that the final EA include a discussion on the perfor ance of the
]
packing, backfill, and fracture lining materials under expected repository temperature conditions (10CFR60.113a).
4 5-5 Section 5.2.1. Excected effects on the chysical environment, oages 5-38 through 5-44 There is no discussion of mineral resources in this section. All information on mineral resources in the draf t EA is presented in detail in section 6.3.1.8,
" human interference (natural resources)" which covers siting guideline l
960.4-2-8-1.
Silence on this issue leaves open the possibility of impacts.
It 4
t is suggested that the expected effects of site characterization on mineral resources be discussed in this section, i
I 5-6' Section 5.2.1.3.1.
Ecosystem impacts, eage 5-41, caragraoh 1 It is stated that " techniques are available for reclaiming surface-disturbed lands with native seed sources." However, it is not stated whether these techniques will be used where appropriate. We suggest that the sentence be i
reworded as follows:
"Available techniques will be utilized to reclaim surface disturced lancs witn native seeds."
5-7 Section 5.2.1.3.1, Ecosystem impacts, page 5-43 The next to last paragraph in this section states that there are no scientific data available to prove a repository will have adverse impacts on fisheries.
Potential impacts to aquatic systems (and thus to fisheries) could result from water Withdrawal from the Columbia River and from site runoff and chemicals at l
the site entering the rivers via Cold Creek drainage.
It is suggested that w
42 1
potential impacts be assessed in terms of the Native American fishery resources potentially at risk.
5-8 Section 5.2.1.3.2, Air cuality imcacts, cages 5-43 to 5-44 No quantitative assessments of emissions and air quality impacts during facility construction and operation are presented.
Therefore, it is not clear on what basis it is concluded that the site, during facility construction and operation, can meet national air quality standards.
It is suggested that emissions and air quality impact evaluations, including models and input data, be provided.
5-9 Section 5.2.1.3.3, Noise imoacts, eage 5-44 Noise related impacts on people due to the construction and operation of road and railroad access to the proposed site are not discussed.
It is suggested that the 00E consider evaluating the transportation noise imoacts and their potential for occurrence.
5-10 Section 5.2.1.3.3. Noise imoacts. cage 5-44 Noise related impacts on wildlife during facility operation are acknowledged but not described qualitatively or quantitatively.
The need for mitigation is also not discussed.
Similarly, noise relatec wildlife impacts due to the access roads and railroad are not discussed.
It is suggested that the final EA consider the noise impacts of cransportation and impacts on wildlife.
5-11 Section 5.2.2, Expected effects of transoortation, page 5-46 The impacts from transportation accidents, including the estimated dose to the maximally exposed Individual and the estimated number of latent cancer fatalities, are not discussed, It is suggested that the final EA include either an explanation of the use of existing analyses and studies to substantiate the assertion that transportation accident impacts are small, or an analysis of the consequences, probabilities ~, risks and cleanup costs for a severe transportation accident enroute to the site.
i I
43 5-12
~
Section 5.2.2.3, Highway transoort, pages 5-48 through 5-50 Certain transportation corridors along the routes to the sites, for example, those with high accident frequency or high waste traffic volume, or adverse weather conditions are a potentially important issue. Although the radiological risks along these special corridors are estimated to be small, such corridors may be subject to increased state and local emergency response actions. This response may be costly and could be disruptive to communities.
It is suggested that this type of consideration be included in the DOE's assessment of transportation impacts.
5-13 Section 5.2.2.5, Potential radiological effects, page 5-52, first paragraph The paragraph implies that under normal conditions of transport, no radioactive material would be released from the shipping containers. While this may be true for the contents of the package, there have been cases of contamination being released from the package surface during transport.
It is suggested that the potential radiation doses to radiation workers involved in close proximity to decontamination ef forts be addressed in the final EA's.
5-14 Section 5.2.3.1. Pooulatien density and distribution, eage 5-59, caragraoh 1 No indication is given of the uncertainties of the labor force estimates used in the socioeconomic analyses.
The size of the labor force during construction, operation, and closure is a major determinant of socioeconomic impacts. Therefore, labor force size and uncertainty would be reflected in the magnitudes and uncertainties of estimates of socioeconomic impacts.
It is suggested that the uncertainty in labor force estimates be assessed and if it is sufficiently large, tne implications for the estimates of sociceconomic impacts be discussed.
5-15 Section 5.2.3.5 Fiscal, conditions and government structures, page 5-66 The discussion in the section on technical and financial assistance for planning and mitigation, should consider how assistance will be provided to assure timely planning.
Early planning is necessary to orevent imoacts that can be mitigated, Many of the tax benefits cited in this section are during construction when it will ce too late to mitigate tne impacts of construction, m
i 44 4
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More emphasis needs to be placed on preplanning potential of financial and technical assistance.
Specifically, the 005 grants may be available during j
site characterization to assist in planning for economic, social, and public health and safety impacts of a repository.
This planning would identify potential impacts and requirements well in advance of the beginning of construction and allow timaly mitigation. A detailed approach to impact mitigation is needed and plans for the timely implementation of studies should
'1 be considered. Mitigation planning is a lengthy process which should take place as early in the repository siting as possible.
It is suggested that there be a full discussion of the timing of pre-impact planning assistance available for mitigation.
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45
)
i Chapter 5 References j
Allen, C.C., 0.L. Lane, R.A. Palmer, and R.G; Johnston, " Experimental Studies j
of Packing Material Stability," RHO-BW-SA-313P, Rockwell Hanford Operations, November 1933.
i Couture, R. A., M. G. Seitz, " Modification of Backfill Materials Under l
Repository Conditions," in Nuclear Technology Programs Quarterly Progress Report, ANL-84-57, Argonne National Laboratory,1984.
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46 CHAPTER 6 :CMMENTS 6-1 Summary, cace 6ti/6-v, paracraoh 1/ Table 6-8 (Geochemistry)
The geochemical data in the draft EA do not appear to acequately succort the favorable findings concerning the qualifying condition for geochemistry.
For example, hydrothermal experiments show that under elevated temneratures (repository conditions) groundwater solution concentrations of carbonate (Johnston, et al. 1984), and fluoride (Aoted and Meyers, 1932) increases. In addition, according to Wood (1983), Wood, et al. (1934) and Allen. et al.
(1983), bentonite (*nien is used as a comoonent to backfitiicacking materia; and typifies fracture filling clays) is ceginning to react nitn grouncoater in three months yielding albite.
Further, experimental *crk Oy Couture and Seit:
(1984) suggest tnat water va:ce at high temperatures causes irreversible degradation of centonite.
4150 redox experiments suggest that ambient redox conditions may be no lower tnan about -0.2 volts, and snat lower values are only achieved by reacting engineered barrier materials witn (distilled) water (Jant:en, 1933).
In addition, Gray (1933 and 1934) reported the production of hydrogen and organic polymers similar to polyethylene in experiments involving Hanford groundwater / gamma radiolysis.
Increases in carbonate and flouride concentrations increase radionuclide complexing potential (i.e. ahich could lead to increases in radionuclide solucility).
The transformation of backfill /
packing / fracture-filling clays will reduce the sorptive cacacity of that material.
Redox conditions influence radionuclide solubility and sorption, and canister containment.
Further, the production of hydrogen and organic colymers could unfavorably affect waste cackage stability and radionuclice trans: ort respectively (see detailed comments 6-27, 6-23, 6-32, and 6-33).
- Thus, assuming that likely geocnemical reactions are favoracle to long-term isolation biases radionuclide releases and transport in favor of low release and nigh retardation during transoort (see detailed comment 6-25).
As stated in the Hanford draft EA, in order for a favorable condition to be claimed or an adverse condition to be disclaimed, it is necessary for tne existing data to clearly or conclusively support snat c:nclusion (craft EA p.
6-4, i3 and p. 7-3, 53).
Further, it is stated that anen the data do not provide clear support, conservative assumptions are used to minimi:e the possibility that later findings will prove the assumptions to be incorrect, and result in radionuclide releases in excess of regulatory limits (draf t EA p.
6-4, 53 and p. 7-3, 53).
Because the geocnemistry data appear to be insufficient to support a conclusive evaluation of favorable condition 2, 3, 4, and 5 and potentially adverse conditions 1, 2, and 3, a generally conservative line of support snould be cresented for each condition.
6-2
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l 47
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Summary, Table 6-A page 6-111 In Table 6-A, and throughout tne draft EA, the 00E states, "The available evidence does not support a finding that the reference repository location is not likely to meet the qualifying condition" (emphasis added).
This type of 1
)
finding, a level 3 finding, is described in Appendix III of the guidelines.
l Unlike the level 3 finding discussed in the craft EA, however, the level 3 finding presented in Appendix III does not refer to evidence that is "available."
Instead, the guidelines require DOE to base its findings on a prescribed level of information, described in Appendix IV, and not on I
information or evidence that is available.
The staff brings this matter to the DOE's attention because one of the Commission's concitions for concurrence in tne guioelines was tnat tne DOE l
should "... indicate the kinds of information necessary for tne COE to make
~
decisions on the nomination of at least five repository sites and subsecuently recommending tnree sites to tne President for enaractert:ation..." (49F;9650).
In resconse, COE acced Accendix IV to tne ouicelines.
Accencix IV lists, guideline by guiceline, the types of information that will ce used for, "...
evaluations and applications of the guidelines of Subparts C and 0 at the time of comination of a site as suitable for characteri:ation." (Appendix IV of 10CFR960).
i The staff excects COE to identify the kinds of information or evidence, as presented in Appendix IV, tnat was used to support the DOE's finding.
The staff suggests that abbreviated description of this information be presented in a third column of Table 6-A with references to where this information can be i
found. A similar treatment is appropriate for Table 6-8.
'Section 960.3-2-3 states that the Secretary of Energy will rely on available information as a basis for his rec mmendation of sites for : Para: tert:ation.
i This "available" information, however, is the information required by Appendix i
IV of the guidelines.
The guidelines make no further reference to "available information."
6-3 Section 6.2.1.3. Site ownership and control, pages 6-15 to 6-16 1
i It appears that not all the lands that may be part of the controlled area have 1
been withdrawn under Public Land Order 1273.
The qualifying condition should j
be applied with respect to lands, including acquired lands, tnat are not covered by that Order.
Further, although it is stated that "present ownership and control of the Hanford site reference repository location and all surface and sucsurface mineral rignts is by tne Federal government and the U.S.
]
Department of Energy," the pertinent part of the applicable Public Land Order 1273 qualifies the withdrawal of the land with the introcuctory chrase " subject I
Y
48 to valid existing rights." The staff suggests that the assessment identify and discuss any such existing rights which could interfere with CCE's jurisdiction I
and control of the site.
6-4 Section 6.2.1.4.4, Potentially adverse conditions, page 6-18 It is not stated that radioactive emissions could be preferentially transported toward localities with higher population densities in the vicinity of the plant.
Since the prevailing wind at the Hanford site indicates preferential transport towarcs Richland, WA, it may not be concluded that this condition is not potentially adverse.
Thus, the evidence may not support the conclusion in tne craft EA tnat enis potentially adverse condition is not substantively present at the reference repository location, i
6-5 Section 6.2.1.4.5, Potentially adverse condition, page 6-18 A potentially adverse condition of Guideline 10CFR960.5-2-3 pertains to extreme weather phenomena in the vicinity of the repository that could significantly effect operational activity at the repository.
There is no mention of possible severe weather conditions that may be encountered by trucks or trains en route from the northeastern utilities and crossing the U.S. to get to this repository.
It is suggested that the potential for this type of delay be given consideration in the final EA.
i 6-6 Section 6.2.1.5, Offsite installations and operations, page 6-20 Guideline 10CFR960.5-2-4 pertains to the location of offsite installations and i
operations and sneir potential ef fset on :ne repository.
Tne draft EA states that the U.S. Army Yakima Firing Center is located 10 miles west of the repository.
There are no details about this military installation discussed in tne draft EA.
It is suggested that more information about the routine functions at this firing range is appropriate in order to evaluate the l
situation and make a determination as to wnether activities there would pose a potential threat to the repository, 6-7 Section 6.2.1.6.3, Favorable conditions Table 6-2, page 6-27
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i No assessments of the magnitude of sources and of the air quality impacts resulting from these sources have been made for construction and operation of the repository.
In Table 6-2, it is stated that site characterization and l
other repository activities are not considered to be a major source.
1 Therefore, the conclusion that all repository activities are not expected to be i
2 a major source is not complete.
It is suggested that an air quality analysis i
and comparison of the results of the analysis to national air quality standardt
)
be performed to determine whether site characterization, construction and r
j facility operation activities constitute a major source.
6-8 i
I Section 6.2.1.6.3 Favorable conditions, page 6-29, Table 6-2, l
1 In Table 6-2, the rows for Endangered Species and for Bald and Golden Eagle l
Protection Act state that bald eagles nest along the Columbia River. According j
to our sources bald eagles do not nest along the river in the area of the
[
]
Hanford site.
They are winter visitors only (Blum,1982).
I I
L 6-9 t
{
Section 6.2.1.7.11. 01soualifying condition, page 6-43, paragraph 6 j
j The analysis of conditions and processes which suggest that with respect to j
radianculide solubility, "... basalt has the capacity to isolate radionuclides l
)
and prevent significant degradation of ground-water quality..." is i
i inacorocriate to the discussion of this discualifying condition, The j
discussion is applying post-closure solubility arguments to a preclosure i
condition, i
i 6-10 i
1 Section 6.2.1.8.11. Favorable conditions, cace 6-52 l
In the draft EA, it is concluded that a favorable condition regarding i
meteorological impacts on transportation disruptions is present based only on j
weather conditions at the Hanford site and vicinity.
Evaluation of this I
condition should consider major transportation routes from the reactors to the i
Hanford repository.
It is suggested that the evaluation include transportation i
]
across mountains and, in many cases, transportation across the Great Plains i
region from nuclear power plants.
An analysis of the frequency and duration of I
de'ays along the transportation routes due to severe weather and their i
l Associated hazards may be desirable.
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6-11 i
1 i
50 I
Section 6.3.1.1.3, Favorable condition, eages 6-62 through 6-65 This favorable condition is stated as:
I
"(1) Site conditions such that the pre-waste-emplacement ground-water travel time along any path of likely radionuclide travel from the t
disturbed :ene to the accessible environment would be more than i
(
10,000 years "
The draft EA notes (page 6 83) that "it can be stated tnat available data and current understanding of the ground-water system do not support a finding that
)
the reference repository location is not likely to meet the favorable condition."
j The evidence available at this preliminary stage, as analyzed by tne NRC, suggests there is reasonable doubt that this favorable condition will be met at the Hanford site.
The NRC has identified seven proolem areas witn the travel j
time calculations that are cresented ey the 00E to support their finding that
{
this favorable condition is met.
These areas are:
- 1) problems with the appitcability of previously published travel time estimates (discussed below);
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- 2) problems with the transmissivity data base and the manipulation o those data for model input; 3) problems with the hydraulic gradient data base and the maniculation of those data for model inout; 4) oroblems with the effective thickness data base and the manipulation of those data for mcdel inout; 5) problems with the theoretical basis of the travel time models; 6) problems with i
l l
the presentation of the results of the travel time models; and 7) problems with the definition of the orientation and lengths of flow paths from the disturbed
- ene to the accessible environment.
These problems are described in detail in I
the comments on specific cortions of chapter 6 provided below.
i h
6-12 i
i Section 6.3.1.1.3, Favorable condition, page 6-62 through 6-65 i
l Seven oreliminary studies of pre waste emolacement ground water travel time performed by various 005-furJed and NRC investigators etween 1931 and 1H4 are
'l cited in the draft EA in support of tne finding on the presence of this favorable condition. With the exception of the NRC (1933) study, and the Arnett and Sagar (1984) study, all studies yielded median ore weste emolacement I
ground water travel times from the edge of the underground facility to the accessible environment in escess of 10,000 years. As discussed below, eacn of i
the available studies has been reviewed by the NRC, and each is considered to l
represent optimistic and non-conservative preliminary predictions of ground water travel time.
Selected comments on each of these documents are summarized below.
The LATA (1981) study Is based on a hydrogeologic conceptual model which is now i
outdated and offers an overly optimisste assessment of ore waste emplacement i
61 l
ground-water travel time, according to data obtained subsequent to the study.
l The conceptual model adopted by LATA for this study assumed a 244-meter tnick aquitard to be present between the repository horizon (assumed by LATA (1981)
I to be the Umtanum interior) and the Vantage interbed (assumed by LATA (1931) to be the first aquifer above the repository horizon).
The Vantage aquifer is assigned a horizontal hydraulic conductivity of 3 x 10 m/sec. However, subsequent data collection has indicated the presence of other aquifers, which may provide preferential condutts for ground water flow, between the Umtanum interior and the Vantage interced.
For example, the Umtanum flow top.
Cohassett flow bottom, Cohassett flow top, and Rocky Coulee flow top all appear to have horizontal hydraulic conductivities comparable to or greater than the assumed Vantage interbed horizontal hydraulic conductivity.
Preliminary tests suggest that the horizontal hydraulic conductivity of the Cohassett flow bottom is at least two orders of magnituce larger than the assumed Vantage norizontal hydraulic conductivity (Strait and Spane,1932). Also, the LATA (1931) study assumed effective porosities for both aquifers and aquitards to be at least an order of magnitude greater than the effective porosity suggested ty Hanford site tests of basalt flow toos (Gelnar,1982), Leonnart et al.,1954).
Based on this information, the NRC considers the LATA (1981) study to be outdated and optimistic, based on the evidence.
It should also be noted that the LATA (1981) study suggests an upward flow path in a northerly direction to the Columbia River.
This is contrary to the preferred preliminary conceptual model by the 00E in the draf t EA of deep ground water flow in a southwesterly direction from the RRL.
The Cove, et al. (1981) study also uses effective corosities at least an order of magnitude higher than the Hanford site data (Gelhar, 1982), Leonhart, et al., 1984) suggests.
The modeling of each major basalt sequence (Grande Ronde,
'wanapum, and Saddle Mountains) as a single (" lumped") layer in the model may also result in inflated ground-water travel time estimates, in that the impact of individual hydrostratigrachte units of higner conductivity, which may be preferential conduits for ground wate* flow, on ground water travel time is masked by the averaging process.
Due to these non-conservative assu ptions, the ground water travel time predicted by the Dove, et al. (1981) model, which was intended only as a demonstration of modeling capabilities, is not considered a viable support document for travel times cresented in the draft i
EA.
The Cove, et al. study also suggested an upward flow patn north to tne Columeia River.
The Arnett, et al. (1981) model has also been reviewed by the NRC (Lehman and 1
I Quinn,1982) in a comparative evaluation with the Cove, et al, (1981) model, fhis model also assumes inappropriately low values for hydraultc conductivities (through lumping of hydrostratigraphic units) and ef fective corosities.
- Alto, l
problems also eWist with the hydrologic boundary conditions imDosed on the Arnett, et al. (1981) document (Lehman and Outnn,1982; Quinn,1982).
l Therefore, this model is also considered to be unreliable and overly optimistte in terms of pre weste-emplacement ground water travel time predictions.
l l
l
9 52 l
Theturnham(1983)docuImentcitedinthissectionofthedraftEAcontainsno modeling, analytical studies, or calculations to support its statement that "it is our conclusion that, in all probability, the Hanford site will demonstrate a pre-emplacement ground water travel time in excess of 1,000 years when fully characterized." This document thus adds no technical support to the DOE's contention that ground-water travel times are itkely to exceed 1,000 years.
The Clifton, et al. (1983) document assumes strictly horizontal flow through a single, " representative" flow top.
Clifton, et al. (1983) use ensemble statistics for all flow tops to describe the random variations of i
transmissivity within the " representative" flow top.
The ensemble statistics yield a legnormal distributton of transmissivity with a geometric mean of 1.65 2
)
ft / day and a standard deviation of log transmissivity of 1.83.
The use of the i
ensemble statistics for fcentification of the especteo pre waste-emolacement i
ground water travel time along "any pathway of likely and signtficant
)
radionuclide travel" may not be sopropriate since, in a layered system, the i
faster caths of hori:ontal travel will be within the most transmissive :enes, J
wnicn co not e niett transmissivities on the low end of the ensemote t
districution (see detailed comment 3-22).
Therefore, travel time througn a flos too of generally higher conductivity may be much lower than that determined by the statistical manipulation of transmissivities for all flow tops.
The use of the ense-Die statistics may be appropriate for vertical flow in : layered system, or for hori: ental flow in a randomly heterogeneous unit whien disolays the same vartance, median, and distribution described by Clifton, et al. for the ensemole of flow tops.
However, this type of treatment is inappropriate for describing single randomly heterogeneous units which have a higher median transmissivity and/or a lower variance (see detailed comment 3-22).
The high variance assumed in the Cit f ton, et al. (1983) model is of particular import due to the assumotion of a five-kilometer sostial correlation i
range of transmissivity within the two-dimensional (20 km x 10 km) numerical i
model (see detailed comments 6 101, 6-102 and 6-103).
This results in the l
median ground water travel time being highea than the ground water travel time calculated using tne median value of the Clifton, et 41. (1983) transmissivity t
i distribution (Citfton, 1984).
Further support for this choice of correlation range is appropriate.
Additional concerns with the numerical modeling assumotions in tre Clif ton, et at. (1933) and Clif ton, et al. (1994) models are discussed in detailed comments 6-101, 6 102 and 6-103).
l The effective porosity assumed e/ C1tfton, et al. (1983) is more than an order l
of magnitude higher than the limited Hanford data would suggest, resulting in overly optimistic pre waste emplacement ground water travel time predictions.
The use of the existing flow too effective porosity data (Gelhar, 1932; Leonhart 1984) would shift the median ground water travel time suggested by the C11f ton, et al. (1983) stud / from tre calculated 17,000 years to less than 680 years (Gord)n,1984).
The Clif ton, et al. (1984) study is similar to the Clif ton, et 41. (1983) stud /
except that, in addition to transmissivity, effective porostty and hydraulic gradient nere also assumed to De asndom vs*iaeles.
'Jn i f o rai distetDuttons were i
53 chosen by Clifton, et al. (1984) for both variables in order that any value
~
within the specified range would have an equal probability of occurrence.
For wide ranges in the input variables, the untfo.rm distribution weignts the mean I
towards the higher values, relative to the loguntform distribution.
Therefore, for given ranges in the input variables, a uniform distribution will be non-conservative (compared to a log uniform distribution) for effective porosity (or effective thickness), and conservative for hydraulic gradient, in l
terms of the resultant travel time calculations.
i The specified range for the regional gradient in the Clifton, et al. (1984) model was chosen to be from 10 to 10; this is considered by NRC to be an i
inappropriately Itmited range in that gradients greater than 1 x 10 can be inferred from existing data (from COE.1982: Yeatman and 8'yce. 1934; and Swanson and Leventhal,1984) (see Table 1 and detailed comment 6-15).
The specified range for ef fective porosity was cnosen by Clif ton, et al. (1984)
I to be from from 10 to 10'#, with a uniform districution, naving a mean of 0.005; this range is also considered by the NRC to ce inappropriate since extstingdataforthesingleflowtoptestedsuggestaneffectiveporosity between 10 and 10" (i.e., not as high as 10' ) assuming porous continuum flow (as is done in all of the pr'evious cited analyses).
The effective thickness in the Clif ton, et al. (1984) model has a mean of 0.04 for the assumed 8-meter thick flow top.
This ($ almost an order of magnitude higner than the single measured value for a Grande Ronde flow top.
Clffton, et al.
(1984) base their choice of the range of ef fective thickness on the suggestion of Loo, et al. (1984).
Loo, et al. (1984) base their suggestion on a combination of the Hanford site test results, laboratory analyses, generic literature values for total and apparent porosities, and the results of a poll of expert panelists.
The NRC considers that expert opinion and generic values are less reliable than direct in-situ testing when such testing ts feasible, as 15 the case for effective thienness testing.
Tne range suggested oy L.co, et al. is considered by the NRC staff to be non conservatively biased towards high values, as is the Loo, et al. choice of a uniform dirtributton for the parameter (Gordon,1985).
l f
The results of the C11f ton, et al. (1984) study suggest a median ground water travel time for a ten-kilometer long horizontal flow path within a single
" representative" flow top of 81,000 years, and less than a W probability that r
the travel time will be less than 1,000 years.
However, the individual chosen parameter distributions, as noted above, are considared by the NRC staff to be non-conservative and inconsistent with the esisting data.
Tnerefore the results, wntch compound this optimistic telection of parameters, are considered to be overly optimistic and do not adequately support tne draft EA conclusion that ground water travel times are likely to enceed 1,000 years.
Several additional comments bearing on the reliability of the travel time analyses are common to all of the soave analyses.
None of the studies cited in the draft EA consider tne potential impact of structures and large s: ale l
heterogene1 ties, nor small-scale noterogeneities such as interconnected 1
3 1
l 54 fractures and fracture networks, on ground-water travel time.
These features may have a positive or a negative effect on calculated ground-water travel times.
The LATA (1981) document contains an additional (uncited) study of a single fault scenario; however, the effects of the fault on groundwater flow were masked in the LATA (1931) model by the averaging of the hydraulic properties of a 1 meter wide fault within a 4000 meter x 4000 meter model grid block. As yet there have been no conclusive studies which detail the imoact of structural and stratigraphic features on ground water travel time at the Hanford site.
Also, there is currently no site-specific data available on l
vertical hydraulic conductivities of the basalt units, which are critical parameters for hydrogeologic performance assessment.
Finally, the gradients and boundary conditions assumed in the above-cited analyses are based on the assumotion that the site hydrology is in steady-state.
However, the degree of i
transience of the hydrogeologic system at the site is as yet unkaewn.
Oa-site l
l and off-site pumoing and discos 41 activities may oe creating a relatively dynamic hydrogeologic system.
l The guideline (10CF4960.4-2-1) recuires the calculation of ground-water travel stee to be aaplied from the distur:ed :one to the accessible environment.
The calculated ground water travel times in the craft EA are all calculated eitner l
f rom the edge of the underground facility, or for a complete ten-kilometer lateral distance. The cresence of a disturbed Zone, which might extend for a significant portion of the distance between the factitty and the accessible enviroment, has not been accounted for in these calculations.
Thus, the travel time calculations aopear to be non-conservative with respect to flow path lengths.
The NRC acknowledges that further clarification of the definition of the distureed tone is needed, and is currently preparing furtner technical guidance on the calculation of the disturbed zone.
The distance to the ac:essible environment as defined in the Guidelines is defined by a semi-infinite cylinder with a manimum radius of ten A11cmeters fecm the edges of the underground facility and with the top of the cylinder a the land surface.
This is the definition utilfred in the draft EA in ground water travel time calculations.
However, as noted in Section 6.4.2.3.5, suosecuent drafts of the EPA Standard have suggested an accessible environment boundary as close as two kilometers under certain conditions.
Also, page 6-36 of the draft j
EA indicates that the controlled area at the Hanford site will extend only two u tometers from sne surface pruecti2, e< sne undergrud f aco tty.
According to the defirition on page 0 1, the " accessible environment" would therefore cegin at tne two kilcreter limit of the control zone, pre waste emplacement ground water travel times calculated on the basis of a ten-kilometer distance from the calculational origin to the accessible environment may therefore be overestimated if either a significant disturbed zone entsts or if the distance i
to the accessible environment is less tnan ten kilometers.
6-13 19ction 6.3.1.1,5 Favorable cone tton, cales 6 66 to 6 69
55 L
The draf t EA states While characteri:ation is not expected to be easy, a basalt environment does have potentially favorable attributes including the following:
Large-scale hydraulic testing will rely on developed saturated-flow hydraulic theory..."
The theory used in the analysis and performance of large-scale testing at Hanford may have to be developed beyond the current state-of-the-art to account I
for the special features of the basalts at the Hanford site, including well 1
depths, effects of large temperature differences between the surface and deep units, the ef fects of dissolved solids and methane gas, and the fractured nature of sne basalts.
Existing theories used in large-scale test analysis are not well-develooed in terms of these features, which the NEC studies indicate may be very signt ficant for interpretation and performance of dynamic tests i
(Coleman and Gordon, 1984; Golder Associates, 1984).
The draft EA ouotes from the NRC draft Site Technical Dosition on Wydrologic Testing Strategy for BW10 (NRC 1933b).
The quotation is not considered relevant to sne discussion which precedes it about the stage of development of theory for large-scale testing.
The cited sentence states only that direct testing is destr.acle.
The statement a3out relying on " developed theory" in future site characterizaticn might be revised in the final EA to indicate the limitations of currently-develaced testing and analysis methods in deep, high-temperature, l
gas-enriemed grouno water in fractured basaltic media. Also, citation of sne statement from the NRC draft site technical position on hydrologic testing strategy might accroariately be deleted from this section as it does not accear to be relevant to the section.
However, if cited, the NRC draft Site Technical Position should be correctly referenced as " draft."
l 1
l 6-14 Section 6.3.1.1.5 Favorable :endition, page 6-68. parserion 3 The draft EA states snat tne " principals involved believe snat the reference repository lccation has a high likelihood of beleg characterited." The princ1Dals noted include tne U.S. Department of Energy and sne U.S. Nuclear l
Regulatory Commission.
The NRC has not taken a position on the 11helihood of r
the site bet 1g characterizable.
The testing approach outlined in the NRC (1983) represents, in part, a hypothests testing program which mignt reveal substantial difficulties in characterization of the reference repository location.
l 6 15 L
56 Section 6.3.1.1.6 Favorable condition, eages 6-70 through 6-75 This favorable condition is stated as:
"(4) For disposal in the saturated Zone, at least one of the following pre-waste-emplacement conditions exists:
(t)
A host rock and immediately surrounding geohydrologic units with low hydraulic conductivities.
(11)
A downward or predominantly horizontal hydraulic gradient in the host rock and in the immediately surrounding geohydrologic units.
(111)
A low hydraulic gradient in anc. between the host rock and the immectately surrounding geohydrologic units.
(iv)
High effective porosity together with low hydraulic conductivity in rock units along paths of likely radionuclide travel between the host rock and the accessible environment."
The draft EA considers that subconditions (11) and (111), and half of subcondition (1), are met at the reference repository location, and therefore that the favoracle condition is met.
There may be substantial uncertainty in the support for this finding.
The evidence is inconsistent, and alternative findings on these subconditions are possible with existing data, problems with the reliability of the DOE's oreliminary tests of hori: ental hydraullc conductivity for both flow interiors and flow tops have been Wentified by the NRC staf f in the past (NRC,19834; Coleman and Gordon,1984; Williams and Associates, 1984; Golder Associates, 1984).
These problems include those caused oy irregularities in test procecures, improper test analysts, temperature effects, effects of dissolved gas and solids, and the effects of large and small-scale heterogenettles.
The NRC staff has also questioned the representativeness of the single-hole test data for the larger I
scales of interest in repository perfor ance assessment (NRC, 1933b).
Tne 00E j
notes that " horizontal hydraulic conductivities measured (within flow
~
interfors)were meter per second (10 feet per day)," generally less than or equal to 10 However, horizontal hydraulic conductivities as high as 147 feet per day have been measured within flow interiors (Strait and Spane,1983),
j which t$ more than eight orders of magnitude higher than the generally reported values.
Thus, the generally reported values may not be representative of certain significant anomalous Zones of hign hydraulic conductivity, j
No reltable field data currently esists with regard to vertical hydraulic conductivities for flow interiors or flow tops. An initial field test of vertical hydraulic conductivity of a flow interior ($ pane, et al.,1933) is I
cited in this sectio 9, Scane, et al. (1933) recorted a vertical hydraulic I
57 conductivity of "less 1.han 10 meters per second" for the Rocky Coalee flow interior.
However, the NRC studies (Golder Associates,1984) indicate that the test arrangement was not approp*iate for the type of tests performed, and therefore there are substantial questions regarding the usefulness of the test results.
Furthermore, alternative interpretations (e.g., Brown,1984) of the test results are possible which could yield a vertical hydraulic conductivity up to two orders of magnitude greater than that calculated for the draft EA.
The draft EA cites two references which describe model-calculated and statistical estimates of vertical to horizontal hydraulic conductivity anisotropy ratios.
One of the cited documents (00E, 1982) is apparently misreferenced, as the document contains no discussion of the 2:1 estimate of anisotropy, which the draft EA attributes to the cocument.
The other document (Sagar and Runchal,1982) is a demonstration of a statistical technioue for analycing the effects of fracture size and data uncertainties, based on fracture set orientation information gained from a rock sample taken from Gable j
Mountain.
The Sagar and Runchal (1932) document is based on assumptions regarding fracture frecuency, acerture and length, which bear no relation to site specific data (Gordon, 1984).
In fact, Sagar and Runchal (1982) state that "the calculations... are intended as an illustrative example and not as a I
definitive statement on the hydraulic conductivity of the fractured basalt at Gable Mountain." Therefore, the cited anisotropy ratio of 3.5 to 1 derived by Sagar and Runenal (1982) should not be considered to acoly, in general, to Hanford basalt flow interiors.
Considering the lack of information on host rock vertical hydraulic conductivities and the unreliability of the existing information on host rock hort: ental hydraulic conductivities, the NRC staff can not determine at this point whether the first half of subcondition (i) of this favorable condition (low hydraulic conductivity of host rock (i.e., candidate flow dense interior))
exists at the Hanford site, contrary to the draft Et finding.
Regarding hycraulic gradients (succonditions (ii) and (iii)), the statement in this section that the gradients are downward or predominantly horizontal appears to be contradicted on page 6-231, where it is stated that a slightly ucward natural gradient exists across the preferred candidate horizon.
- Also, Clif ton, et al. (1984, page 13) state snat "tne overall vertical hydraulic gradient in tne Grande Ronde basalts from the Umtanwn flow top to the Ginkgo flow top was estimated to be approximately 2 x 10~ as measured in three pietometer nests during late August, 1984 (Bryce and Yeatman, 1984)."
This suggests a relatively high upward gradient compared to the horizontal hydraulic gradient. On page 6-72, it appears that the vertical gradient is downward in i
the upper basalt layers and upward in the lower basalt layers.
Under the assumed steady-state flow conditions, this would require some kind of vertical 1
flow sink at the point of gradient reversal, for which no mechanism has been suggested.
The hydrologic baseline monitoring program currently underway at the Hanford site may provide additional resolution of the question of the three dimensional distribation of hydraulic gradients.
58
~
The magnitude of the bydraulic gradient in and between the host rock and surrounding geologic units, based on existing data (see Table 6-1) may be 2
estimated to be higher than 1 x 10 foot per foot, rather than approximately 1
.s x 10 foot per foot, as the draft EA suggests. The areal gradient I
T 4
1 A
i i
m
_..__m___
1ABLE 6-1 C0ttPTEISDN OF APPARENT AREAL GRADIENTS FOR SELECIED HASALT FLOWS IN TitC GRANDE RONDE BASALT Approximate Direction j
of inferred average i
Average head gradient head gradient between Stratigraphic flow Comparison of observed heads between borchnles boreholes within interval (ft above MSI) within interval intervals llead in llead in RRL-2 00-22
-4
-4 Rocky Coulee 401 to 402 396 to 397.5 3.5 x 10 to 6 x 10 Northwest
-4
-4 Cohassett 397 401 to 401.5 4 x 10 to 4.5 x to Southeast Head in llead in RRL-2 DC-19
-4
-4 Cohassett 397 400 to 400.5 1.6 x 10 to 1.8 x 10 Northwest Head in licad in RRL-2 DC-20
-4 Rocky Coulee 401 to 402 402.5 to 403 6.0 x 10-5 to 2.4 to 10 Southwest Cohassett 397 402.5 to 403 6.6 x 10-to 7.2 x 10
- Southwest f
Ilead in Head In RRL-2 RRL-14 t
-4 RoSky Coulee 401 to 402 402 to 405 0 to 4.8 x 10 Southeast 1.4 x 10-3 Southeast Cohassett 397 409 0
9
-=,
.m b
TABLE 6-1 (Continued)
COMPARISON OF APPARENT AREAL GRADIENTS FOR SELECTED BASALT FLOWS IN Tite GRANDE RONDE BASALT Approximate Direction of inferred average Average head gradient head gradient between l
Stratigraphic flow Comparison of observed heads between boreholes boreholes within i
interval (ft above MSI) within interval intervals
'[
\\
Head in Head in DC-22 RRL-14
-3 Rocky Coulee 3% to 397.5 402 to 405 1.7 x 10-3 to 3.5 x 10 North f
-3
-3 Cohassett 401 to 401.5 409 2.9 x 10 to 3.1 to 10 North Head in Head in 00-19 DC-22 Cohassett 400 to 400.5 401 to 401.5 1.7 x 10-5 to 5.1 to 10-5 Southeast Head In Head In DC-12 00-19 Cohassett,
407 400 to 400.5 3.1 x 10 to 3.3 x 10
- Northwest
-4
-3 Rocky Coulee 401 to 402 401 to 407.5 0 to 9.3 x 10 Northeast l
i i
E
61
~
is calculated by comparing heads between individual pairs of boreholes.
This procedure may be questionable, because hydraulic gradients should be calculated in the direction of flow, which may or may not be along a path cetween boreholes.
Therefore, the draft EA may underestimate the actual hydraulic gradient, because the gradient calculated between boreholes will be less than, or at most equal to, the actual gradient.
The direction of the gradient can not be determined at this time.
In any case, there is substantial uncertainty with respect to the gradient and the degree to which subconditions (,11) and (iii) are satisfied.
The draft EA states on page 6-75 that, because flow tops may be expected to have a higher effective porosity than dense interiors, "radionuclide movement would have taken place in basalt layers having both high and low effective corosities." The results of preliminary testing in a flow top indicate that flow tops may also have a low effective porosity relative to other geologic media. Therefore, we suggest that the statement quoted aoove might be reworded to read "radionuclide movement would have taken place in layers having both higher and 1cwer effective porosities."
The above information, we consider that the available information suggests tnat there is substantial uncertainty in the technical support for the finding on this favorable condition made in the draft EA.
6-16 Section 6.3.1.1.6, Favorable condition, page 6-73, Table 6-5 Borehole DC-12 apoears to have been omitted from the tabulation of head data provided in the draft EA.
Borehole DC-12 lies between boreholes RRL-2 and DC-15. The NRC staff noted in NRC (1983a) that a direct line gradient between RRL-2 and DC-15 is inappro,ariate because the head derived from the drill and test sequence at CC-12 is nigher tnan the head in either of these carenoles.
This is important to the development of a conceptual model of ground water flow in the Pasco Basin.
6-17 l
Section 6.3.1.1.6, Favorable condition, page 6-75, paragraph 3 This section of the draf t EA discusses the field tracer experiment for determination of dispersivity and effective porosity.
This section states that the effective thickness of the test horizon ranges between 2x10 ' and 3x10
~
m (0.006 to 0.01 ft).
The definition of effective thickness, used in this section, is inconsistent with the definition which was used during previous data gathering and workshop meetings with Hanford personnel.
This proolem can be resolved by defining the phrases used in the analyses and presentation of data and adhering to these definitions.
Also, refer to detailed comment 3-24
62 which questions the strtement that, to date, two tracer tests have been performed within the McCoy Canyon flow top.
6-18 Section 6.3.1.1.8, Potentially adverse condition, page 6-76 This potentially adverse condition is stated as:
"(1) Expected changes in geohydrologic conditions - such as changes in the hydraulic gradient, the hydraulic conductivity, the effective porosity, and the ground-water flux through the host rock and the surrounding gechydrologic units - sufficient to significantly increase the transport of radionuclices to tne accessicie environment as ccmpared with pre-waste-emplacement conditions."
The draft EA does not accear to adecuately. censider the possible changes in geohydrologic ccnditions compared with pre waste-emplacement conditions in reaching the finding that this potentially adverse condition does not exist.
For example, ground water usage, irrigation practices, waste-water disposal activities, and repository-induced effects do not appear to be adequately considered.
The regional hydraulic gradient may be changed as a result of ground water use 4
such as pumping (for irrigation, etc.), injection or wastewater application outside of the controlled area.
These practices are not considered.
As an example of the impact of ground-water usage on the hydrologic conditions in adjacent basins, ground-water usage is increasing in regions to the northeast, east, and west of the Hanford reservation, causing 200 to 300 foot drops in the height of the water table in the adjacent Quincy Basin (Cook, 1984).
The projected water usage outside of the controlled area within the Pasco Basin and surrounding region snould oe considered by the COE in applying this guicoline.
Irrigation using Columbia river waters would also be a factor in providing artificial ground-water recharge. Within some areas influenced by the Columbia Basin Irrigation Project, significant rises in unconfinec water levels occurec.
Potentiometric levels in underlying basalt aquifers rose as much as 20 to 40 ft/yr af ter the beginning of irrigation (Gephart, et al.,1979).
Previously the DOE has investigated the probable impacts of constructing water control structures along reaches of the Columbia that lie within the Hanford reservation (COE, 1982).
One proposed project which had been intensively studied was the Be.. Franklin Dam (Harty, 1979).
If constructed, this reservoir would be sited along the Hanford Reach of the Columbia about fivi miles north of North Richland.
Such a structure would greatly increase water levels in the unconfined aquifers underlying the northeastern portion of the Reservation.
Water levels in the unconfined system underlying the reference repository
- - - =
i I.
63 a
location would be increased by as much as-ten feet if the dam was to be 1
j maintained at a pool elevation of 400 feet (Harty, 1979).
t j
The effect of repository-induced thermal loadtng has also not been adequately addressed in this section.
For instance, the draft EA states, that "this loading is predicted to extend a limited distance (several hundred meters) from the repository. Such a lateral distance is a relatively l
small portion of the 10 kilometers (6.2 miles) separating the recository i
i from the accessible environment.
Therefore, any change in the local hydraulic characteristics resulting from thermal loading should not have a significant impact on the total ground water travel time calculate from j
witnin tne flow top of the host rock to the accessible environment."
First of all, the staff considers that "several hundred meters" may be a significant portion of the distance to the ground surface, which serves as the upper boundary to the accessible environment.
Furthermore, if, the draft EA states on page 6-36, the controlled area will extend only two kilometers from i
the surface projection of the repository, the lateral boundary of accessible l
environment as defined on page G-1 will be substantially closer to the i
facility.
Sicondly, the recository-induced thermal loading will affect the dynamic viscosity, the density, and the kinematic viscosity (the ratto of dynamic viscosity to density) of the ground water.
These changes will cause an increase in hydraulic conductivity (due to a decrease in kinematic viscosity) and an increase in the vertical hydraulic gradient due to fluid buoyancy.
The NRC studies suggest that these post-emplacement enanges can have a significant effect on ground-water travel time (Wang, et al. 1983: Gordon and Weber, 1983; i
Tsang, et al., 1984).
i t
Another possible source of future hydrologic changes is the practice of onsite L
i liquid waste disposal.
Disposal activities have oeen concucted at numerous i
sites within the reference repository location and have continued at varying l
discharge rates up to the present.
Figure 3-26 on page 3-59 of the draft EA depicts surface water bodies on the Hanford Site and includes the locations of i
a numcer of man made ditenes anc ponds used for the routine disposal of i
wastewaters. This figure shows only two disposal sites within the perimeter of the reference repository location.
However, many more locations within the reference repository location have previously been used as disposal sites, Some of these sites are depicted in Figure 6-1, based on data from ERDA, 1975.
i i
Newcomb, et al. (1972) quote Belter (1963) in stating that between 1945 and 1959 over 40 billion gallons of radionuclide-bearing liquid wastes were discharged to groundwaters of the Hanford Site.
In a more recent technical j
review (CRWM,1978) it was reported that as of January 1975 about 130 billion J
(
l i
i e
4 l
DC-18 (proposed)
DC-23 (proposed) o McCEE DC-4/5 08 1]
DC-20 cluster O r rena cA?;'.,
- DC-22 cluster O 231 oitch e
2 00 West Area RRL-14 RRg-25 (proposed)
~
RRl,-2 Q 216-U-14 I; itch U I""d RRL-6 i
O Redo rond o 222-s ro N
DC-16 cluster i
Figure 6-1 : Approximate locations within Llie reference DC 19 cluster 0
1 2
repository location of some present and former liquid waste disposal sites K11 tm.
(based on data from ERDA, 1975).
65 gallons of effluent had been percolated, largely in and near the two 200 areas.
These activities generated ground-water mounds in the unconfined hydrologic systems which received the liquid wastes.
Newcomb, et al. (1972) refer generally to the " eastern" and " western" mounds, and to smaller mounds generated at other locations.
The so-called " western" mound was recharged at 3 or more surface locations which were within the defined area of the reference repository location.
In 1961 the " western" mound reached a peak height of 60 ft. above the natural water table and had a basal area of about 15 square miles (Newcomb, et al., 1972).
The NRC staff considers that these disposal activities may have caused significant changes in the geohydrologic regime, including the confined aquifers which underlie the reference epository location.
Figure 5-41 of the 00E's Site Characterization Report (CCE,1982) shows 10 hydraulic head measurements collected using crill and test tecnniques in borenole RRL-2, located in the heart of the reference repository location.
According to this Figure, hydraulic heads decrease with depth from the Mabton Interbed down to the upper Grande Ronde basalts. then increase with death down to the Umtanum Basalt. A similar trend reversal appears to exist in data frcm borehole DC-16A (Figure 5-40, 00E,1982).
Data from each of the newly constructed (1984) piezameter clusters at OC-19,20,22 also show decreasing heads with depth down to the Priest Rapids member of the Wanapum Basalt.
l These changes in heads constitute anomalies which suggest transient hydrologic responses. Downward recharge apoears to be the most likely explanation for these gradient changes at depth.
It is entirely possible that a f
downwardly progressing change in hydraulic heads occurs in response to four l
decades of liquid waste disposal.
In other words, heads measured near the l
reference repository location, and cerhaps at other locations ensite, may not be representative of pre-1940 steady-state conditions.
If this conclusion is correct, it may have significance with regard to the isolation potential of the layered basalts at Hanford.
There is a question concerning the statement in the draft EA that if the ground-water travel time calculations described in Section 6.4.2.3 were to take credit for fluid movement through the flow interior of the host rock, then i
" travel times to the accessible environment would be much longer tnan now predicted." Oue to the very small (at most, tens of meters) likely distance of travel through the flow interior of the host rock, and the very low effective porosities that are expected within the interior, the ground water travel time through the dense interior to the overlying flow top may be insignificant in comparison to lateral travel time through the flow top to the accessible environment. This is based on the draft EA conceptual model of horizontal ' low through an overlying flow top to the accessible environment, which may or may not be reflective of actual hydrologic conditions at the reference repository location.
Based on the evidence, the statement that "no significant post-waste-emplacement changes to [the calculated pre-waste-emplacement] travel s
d 66
~
tires are expected," is also questionable.
The effects of long-term geologic j
I conditions and processes on ground-water flow is dealt with in more depth in detailed comment 6-49.
There have been insufficient studies to reach definite conclusions on the potential for significant increases in transport of radionuclides to the accessible environment as compared with pre-waste-emplacement conditions.
However, the available evidence [ Wang, et al. 1983; Gordon and Weber, 1983; Mercer, et al., 1982] suggests that there is (as yet unquantified) potential for significant increases in radionuclide transport caused by i
post-waste-emplacement, repository-and man-induced changes in geohydrologic properties.
Therefore, based on the limited existing information, there is reasonable doubt tnat this potentially acverse condition may be dismissed for the Hanford site reference recository location.
6-19 l
Section 6.3.1.1.8, Potentially adverse condition, cace 6-76, caragraph 2 The draft EA states that this potentially adverse condition regarding changes in gechydrologic conditions does not appear to be present.
However, this aopears to conflict with the finding on draft EA page 6-144 in which it is j
assumed that the potentially adverse condition regarding impacts of human activities on the ground water flow system could be present. As described in the draft EA, the foreseeable human activities include ground water withdrawal, i
extensive irrigation, subsurface injection of fluids, underground pumped storage, military activities, or the construction of large-scale surface-water i
I imooundments.
This apparent discrepancy merits consideration in preparation of the final EA.
6-20 Section 6.3.1.1.9. Potentially adverse condition, page 6-77 The assessment of this condition does not appear to take into account information on the actual chemistry of groundwater taken form the Grande Ronde or other zones in Washington and Oregon for crop irrigation purposes. While the Grande Ronde water may not be ideal for irrigation purposes, it appears to be of better quality (according to Table 3-6) than some water which has been used for irrigation in arid areas of the U.S. (Federal Water Pollution Control Administration,1968).
In addition, it might be accropriate in some areas to utilize the average or mixed water chemistry for all' sources between the water table and the deepest zone of interest.
For example, deep irrigation wells could draw water from a
67 several strata (i.e., borehole dilution), mixing it in the process and thereby more efficiently using the entire available water resource.
Re-evaluation of this potentially adverse condition might be considered in the final EA.
6-21 Section 6.3.1.1.11, Disoualifying condition pace 6-79 The draft EA makes a level 1 finding against the disqualifying condition for groundwater travel time.
Tne finding states, "The available evidence does not support a finding that the reference recository location is disoualified (level 1)" (emchasi s added).
The level 1 finding stated in the draft EA refers to "available" evidence while the level 1 finding required by the guidelines does not.
The apparent inconsistency should be resolved in the final EA.
6-22 1
Section 6.3.1.1.11.2, Radionuclide releases, page 6-82-83. caragraoh 3. 4/1 and Section 6.3.1.1.11.3. Reducino data uncertaintv. cage 6-84 caracraoh 1 The discussion of geochemistry and radionuclide solubility in these sections do not appear to relate to the disqualifying condition being addressed, i.e., "a site shall be disqualified if.
groundwater travel time is
., less than 1000 years." Groundwater travel time appears to be addressed in this section rather than radionuclide solubility.
l 6-23 Section 6.3.1.1.12, Conclusion on the cualifying condition cage 6-85 The draft EA states:
concludes, "--- the available evidence does not support a finding tnat tne site is not likely to meet ne qualifying condition (level 3)."
The favorable geochemistry of the deep basalts is cited as a major factor that supports the finding on the cualifying condition for gechydrology:
"The geochemical characteristics of the deep basalts appear favorable for reducing radionuclice concentrations and limiting radionuclide migrations and extending waste canister lifetimes." However, the qualifying condition deals with geohydrology, not geochemistry.
The discussion might accropriately address how groundwater flow, rather than geocnemistry, would influence the concentration and migration of radionuclides and the lifetime of the waste canister.
4 9
68 I
6-24 l
Section 6.3.1.1.12, Conclusion on qualifying condition, oage 6-85 Several of the factors which the draft EA cites in support of the preliminary finding on this condition have been discussed in preceding comments.
In particular:
o As noted in detailed comment 6-11, t5ere is reasonable doubt that I
ground-water travel time from tne di%turbed zone to the accessible environment is in excess of 10,000 years along flow paths of likely and 4
significant radionuclide travel.
o As stated in Section 6.3.1.1.5, and discussed in detailed comment 6-13, tne site does not appear to be readily amenaole to characterization or modeling with reasonable certainty.
The statement in the second bullet of Section 6.3.1.1.12 seems to contradict this previous statement in Section 6.3.1.1.5.
o As noted in detailed comment 6-15, the hydraulic gradients in any 4
j direction may be higher or lower than the cited value of 10
, depending i
on the well pair used in the calculation.
o Detailed comment 6-18 notes that human-and repository-induced changes that could affect the deep hydrogeologic system have been inadequately addressed in applying this guideline.
Consideration of these points seems appropriate before making a finding on the i '
presence of this qualifying condition.
i 6-25 Section 6.3.1.2, Geochemistry (Section 960.4-2-2), oage 6-87-88, paragraph 3,4/1,2 The geochemistry data do not appear to fully support an evaluation that the likely geochemical reactions between the basalt rock, ground-water and the materials that would be empla:ed are favorable for long-term isolation.
Five examples of non-supportive data are cited in this paragraph:
(1) hydrothermal experiments show that under elevated temperatures (recository conditions) groundwater solution concentrations of carbonate (Johnston, et al.,
1984), and fluoride (Apted and Myers,1982) increases; (2) according to Wood (1984) and Wood, et al. (1981), bentonite (which is proposed as a component of backfill / packing material and typifies fracture filling clays) is beginning to react in three months, under repository conditions, to yield albite; (3) according to Couture and Seitz (1984), water vapor (steam) has great ability to rapidly alter clays; (4) redox experiments suggest that ambient redox
1 69 conditions may be no lower than about -0.2 volts (Jantzen, 1983); and (5) Gray (1983) reports the production of hydrogen, and organic polymers similar the polythylene, in experiments involving Hanford groundwater / gamma radiolysis.
These data are non-supportive of conditions favoring waste isolation for the following reasons:
(1) increases in carbonate and fluoride increase radionuclide complexing potential, which could lead to increases in i
radionuclide solubility; and (2) the observed alterations of backfill / packing / fracture-filling clays leads to minerals that have less j
sorptive capacity than the original materials; (3) site redox conditions have not been shown to be chemically active; and (4) the production of hydrogen by radiolysis of water, and the production of organic polymers from groundwater methane as a result of the repository radiation environment, could affect waste package stability and radionuclide transport repectively.
Also, According to Long and Davidson (1981) and Benson and Teague (1982 and
]
1984), pyrite is a minor secondary mineral. The availability of ferrous 1
minerals to interact with groundwater is key to determining the reducing potential of the basalt / rock system and thus the capacity of the system to consume oxygen after closure.
In addition, some radionuclides, while not readily reduced in groundwater, can be reduced on the surface of fresh ferreous minerals (Bondietti, 1979; Meyer, et al.,1984; and others).
Thus, an overestimate of pyrite or other ferrous minerals could lead to false assumptions concerning future redox conditions, and an overestimate of retardation for those radionuclides effected by the reducing capacity of the rock and not the water (i.e., technetium and neptunium).
Furthermore, there is not clear support that the site redox conditions will promote precipitation and will maintain radionuclides in their least mobile i
j state.
It is the reducing or oxidizing capacity and kinetics of the basalt / water system not " redox conditions" that determine the oxidation state of radionuclides.
For example, Garrels and Christ (1965) and Early, et al.
(1982) indicate that uranium carconate species can exist in an " oxidized" state under " reducing" conditions as low as -0.4 volts.
Since oxidized species are j
more soluble and less readily sorbed than reduced species, the reducing capacity of the system is fundamental in determining radionuclide transport enaracteristics. Also, the draft EA coes not acequately consicer the movement l
of radionuclides that may be transported as particulates or colloids.
- Finally, l
experiments that used hydrazine to provide some indication of how radionuclides would react in a reducing environment (Salter, et al.1981, Barney,1984),
should not be used until the validity of the data is established.
Important concerns with this data are (1) the reaction between hydrazine and any y
reducible radionuclide is undefined, thus the effective redox condition is unknown; (2) hydrazine hydrate dissociation to release hydroxide anions likely 4
dominates the groundwater pH, so the pH is no longer representative of in-situ conditions; (3) hydrazine could react with bicarbonate in the groundwater to form the carbomate anion, which may form radionuclide complexes; (4) hydrazine i
is an agressive chemical and attacks polycarbonate test tubes causing the tubes to crack / break, or result in brown-colored degradation products; (5) nydrazine I
l
i 70 i
may alter or disaggregate clay mineral structures, and change the secondary minerals in the test; and (6) considerable uncertainty exists as to the solid phase or solution species formed by the reaction of hydra ine with somr:
radionuclides such as technetium (Kelmers, 1984).
i 6-26 Section 6.3.1.2.4, Favorable condition (2), page 6-90, paragraoh 2, 3 and 5 It is not clear whether the data support a conclusive evaluation that geochemical conditions "that promote... precipitation.
sorption.
are present.
For example, it is not clear that tne reference repository location has chemically reducing conditions that will promote precipitation and will maintain racionuclices in their least mootle state (see detailed comments 6-28 and 6-33).
Further, the presence of reducing conditions alone does not mean that reduced species will be present in the system.
The assumption that the ground water system has the cacacity to reduce radionuclides tc their least mobile state, biases radionculide release calculations in favor of low releases.
Thus, in order to take credit for having reduced radionuclides in the repository system (i.e. high precipitation and high sorption), the EA should consider data that address the reducing capacity and redox kinetics of the geochemical environment, on a radionuclide-by-radionuclide basis.
If the data is insufficient for a conclusive evaluation, a generally conservative line of reasoning may be appropriate.
i 6-27 i
Section 6.3.1.2.5, Favorable condition (3), page 6-91, paragraoh 2 The data do not appear to fully support an evaluation that site mineral assemblages will remain unaltered or would alter to mineral assemolages with equal or increased capability to retard radianculide transport. According to the DOE-sponsored work, Wood (1983) and Wood, et al., (1984), bentonite (a backfill / packing material / clay which is similar to montmorillonite which is a common host rock secondary mineral) woulc react under repository conditions, to yield small amounts (less than 1%) of albite.
This suggests that bentonite and groundwater and basalt would react to yield albite t chlorite 2 paragonite t illite quartz + H 0; and at this point the new sheet silicates may be 2
hidden as mixed layers in the reacting bentonite.
If this is the case, then at 300 C, even a 0.1% reaction (in three months), proceeding at a constant rate, would alter 40% of the bentonite in 100 years.
In fact, Wood (1983) suggests that at 140*C as much as a 20% change would be expected in the 1000 years.
In addition, according to Couture and Seitz (1984) bentonite reacted in steam shows a decrease in swelling capacity.
Such changes, would alter the character of backfill / packing / fracture filling clays, affecting anticipated sorption reactions and water flow through characteristics.
~
71 I
j Also potassium is leached from basalt at higher temperatures and potassium is known to decrease the stability of smectites (montmorillanite) uncer hydrothermal conditions and to be an effective competitor with cesium for sorption sites (Erberl and Hower,1977 and Salter, et al.,1981).
- Further, according to Charles and Bayhurst (1983) and Myers, et al. (1984), Grande Ronde basalt reacts readily at all temperatures to form both tilite and smectite.
Finally, mineralogic changes of bentonite to illite, or alteration products i
that armor ferrous host rock minerals, decrease the capability of the site to retard radionuclides and, thus results in increases in calculated releases.
l (See detailed comment 6-32.)
6-28 Section 6.3.1.2.6, Favoraoie concision (4), oage 6-91 to 6-92, caragrach 6, continuing caragraon The data do not apoear to succort the evaluation that geochemical conditions constrain the dissolution of the total radionuclide inventory (at 1000 years) to less than 0.001 percent.
The analysis was performed using " expected conditions" (ie redox = -0.3 volts) and assumed that radionuclides were released in their least soluble state.
According to Early, et al. (1982 and 1984) and others, data concerning redox conditions in the Grande Ronde range from +0.35 volts to -0.4 volts; therefore, -0.3 volts may not be a valia expected value. Many radionuclides are orders of magnitude less soluaole as reduced species than they are as oxidized species.
For example, Early, et al.
(1982) calculated that uranium solubility at -0.40 volts has a concentration of l
1.0E-10 mol/1, while at -0.0 volts it is around a concentration of 1.0E-5 mol/l (and becomes more soluble as redox conditions become more oxidizing).
Garrels and Christ (1965) show that uranium and other radionuclide species can exist in an oxidized state under " reducing conditions" as low as -0.4 volts.
- Also, according to Jackwer (1984), Pederson, et al. (1984); and Simonson and Kuhn (1984), actinide solubilities may oe altered oy alpna anc gamma radiolysis through changes in Eh/pH.
It is not clear that credit for such low redox values and associated low solubilities can be supported (see detailed comment 1
6-33).
4 i
Further, experiments determining " steady-state" radionuclide concentrations in basalt / rock / water experiments could underestimate solubility.
As would be expected, the presence of basalt tends to lower the " solubility" of radionuclides in groundwater due to sorption type reactions. Also,
" steady-state" arguments pertain only to very slow moving or no flow systems where steady-state conditions can predominate.
Finally, it is implied tnat since spent fuel is mostly reduced uranium, it will remain relatively i
'insoluable in the Hanford recox environments.
However, according to.
experiments by Grandstaff, et al. (1984) and Myers, et al. (1984) reaction products from basalt / water exoeriments include weeksite or boltwoodite.
Weeksite (boltwoodite) is an oxidized (U* ) uranium phase and thus is more soluble tnan uranium oxide (UC '
--tne assumec pnase uncer "exoected" recox 2
f I
i
72 conditions of -0.3 volts).
Also, experimented studies have shown that some radionuclides (Cs, I) are released into solution at a faster rate than the rate of dissolution of spent fuel matrix (U0 * --uranium oxide) (Johnson, 1982).
2 Consequently, the expected dissolution at 1000 years can be expected to be greater than those calculated using redox conditions of -0.3 volts.
6-29 Section 6.3.1.2.7 Favorable condition (5), page 6-92/93, paragraoh 4, 5/1 The analysis of favorable condition (5) considers only reversible sorption.
The guideline asks for "any combination of geochemical and physical retardation processes that would decrease the precicteo peak cumulative releases of radionuclides to the accessible environment by a factor of 10 as compared to those predicted on the basis of ground-water travel time without retardation"
[960.4-2-2(b)(5)]. According to the COE (1984), cumulative releases of radionuclides mean "... the total number of curies of radionuclides entering the accessible environment in any 10,000 year period...".
The peak cumulative release of radionuclide refers to "the 10,000 year period during which any such release attains its maximum predicted values." By considering only reversible sorption (without regard to radioactive decay or discersion, or any other combination of geochemical and physical retardation processes), the predicted peak cumulative release of radionuclides has not been decreased with respect to that predicted on the basis of groundwater travel time, it has only been delayed. Also, the analysis of radionuclide retardation is icaccurate because it assumes that the entire bulk chemistry of the host rock is available for sorption. 3ince transoort will be through fractures, the predominant minerals that will be available for sorption reactions will be the secondary fracture filling materials.
The aosence of a substantive analysis coes not allow a finding on favorable condition 960.4-2-2(b)(5), and thus could impact the overall qualifying condition for geochemistry [960.4-2-2(a)].
The 00E might reconsider favorable condition 960.4-2-2(b)(5) in the terms specified in the guideline.
This means an assessment of the recuction (by a factor of 10), of the total numcer of curies entering the accessible environment for that 10,000 year period in which the peak release has been re-calculated to occur, as compared to the total number of curies originally calculated in the absence of geochemical and physical retardation processes. An analysis relevant to this favorable condition should consider geochemical processes which immobilize as well as delay radionuclides, rather than conditions which only delay their release.
6-30 Section 6.3.1.2.8, Potentially adverse condition (1), page 6-93, paragraoh 4, tnrougn page 6-95, caragraon 3
l s
73 The analysis presented in the draft EA does not address the subject of the
".. solubility or the chemical reactivity of the engineered barrier system..."
as called for in potentially adverse condition 960.4-2-2(c)(1) (see draf t EA pp. 6-93-94). However, the draft EA states that, " Ground-water conditions in the host rock that could affect the solubility or the chem'. cal reactivity of the engineered barrier system should not compromise expected repository performance...". This statement is substantiated by citing various studies that examined the following: (1) solubility for radionuclides; (2) complexes with radionuclides; and (3) migration of radionuclides; and (4) adsorption of radionuclides after they have been released from the engineered barrier system.
The draft EA does not discuss how groundwater conditions may affect the engineered barriers' performance.
In particular, the draft EA does not examine i
how groundwater may affect tne corrosion rate of the waste canister, the leach rate for the waste form or other engineered materials.
Radionuclide 4
solucility/ complexing / sorption / migration are not engineerec carriers.
The absence of an analysis of the effects of geocnomical conditions on engineered barriers does not allow a finding on potentially adverse condition 960.4-2-2(c)(1). and tnus, in its cresent form. adversely affects the draft EA finding on the overall qualifying condition [960.4-2-2(a)] for geocnemistry.
The final EA might assess how groundwater conditions at Hanford effect the
".. solubility or the chemical reactivity of the engineered barrier system..."
and evaluate how this may influence the containment of radionuclides within the engineered barrier system and the release of radionuclides'from the engineered barrier system.
The 00E could then reconsider the guideline finding.
6-31 Section 6.3.1.2.8. Potentially adverse condition (1), eage. 6-93, caracraoh 4. and 6-94, paragraon 2 The draft EA refers to the possible upward migration of deep ground water in the vicinity of tne reference repository location.
Inis statement is based on the understanding that sodium and chloride concentrations are relatively enriched here.
Data are not presented to support this hypothesis.
This topic j
is pertinent to the EA findings because it affects the direction of inferred j
ground water flow in :ne vicinity of the reference repository location. The direction of ground water flow is particularly relevant to the performance assessment based on ground water travel times and directions of flow.
6-32 Section 6.3.1.2.9, Potentially adverse condition (2), cage 6-95. paragraoh 5 The data concerning sorption and mineral stability do not show that the geochemical conditions, will not reduce sorption of radionuclides. According to Wood (1983) and Wood, et al., (1984) fracture fillir.g clay minerals do have a tendency to alter to less sorptive minerals (see de*.ailec comment 6-27).
In
74 fact, over a period of-1000 years Wood et. al. (1934) suggests that the conversion of smectite clays minerals to illite could exceed 20%.
- Further, according to Charles and Bayhurst (1983) and Myers, et al. (1984), fresn basalt reacts readily to form both smectite and illite.
Illite is less sorptive than smectite clays (see detailed comment 6-25).
In addition, redox conditions are assumed to control redox sensitive radionuclides to their most sorptive oxidation state.
However, these conditions cannot be clearly shown to exist (see detailed comment 6-33).
6-33 Section 6.3.1.2.10, potentially adverse condition (3), pace 6-96, caracrachs 1 :ncouch a The data do not appear to support the evaluation that " pre waste-emplacement ground water.
" are not "... chemically oxidi:ing." For example, the COE analysis of redox conditions and reactions at Hanford. as presented in the craft EA (pages 6-90 to 92, 95, 96) and cited portions of references, do not support an evaluation that expected redox conditions (1) are as reducing as the -0.3 volts used for draf t EA calculations, or that (2) expected reactions will maintain redox sensitive radionuclides in low solubility and high sorption states.
With respect to point (1), Early, et al. (1982 and 1984) and 00E (1982), report that measured recox conditions range from aoout +0.35 volts to -0.2 volts, and that calculated values range as low as -0.4 volts.
Redox measurements on natural waters are difficult to interpret, therefore a calculated redox conditions of -0.3 volts (and lower) are used in the draf t EA as excected site conditions based on three arguments:
(aj The coexistence of titano-magnetite with ferrous secondary iron-bearing phases sucn as pyrite, ano tne lack of naturally occurring ferric iron-bearing phases such as hematite; (b) Occasional occurrences of sulfide ions coexisting with sulfate ions, and methane coexisting with caroon cioxice; and, (c) Data from rock / water interaction experiments.
The essence of argument (a), is that hematite is stable only in moderately to strongly oxidizing environments; while in chemically reducing environments, pyrite or magnetite is stable (Krauskopf,1967).
However, Benson and Teague (1979), report that an oxidized iron phase, possibly nematite is present within smectite at Hanford (smectite is a common, fracture-filling seconcary clay mineral). Argument (b) suggests that the redox couples sulfide / sulfate and methane / carbon dioxide are another source of (indirect) evidence that supports the presence of reducing (i.e. non-oxidizing) conditions at the site.
- However, equilibrium between sulfide / sulfate, and methane /caroon dioxice is unusual,
l
\\
1 75 because such reactions require biological mediation; and furthermore, the couples are not generally found to be electrochemically active (Hostettler 1984; Ohmoto and Lasaga 1982; Stumm and Morgan 1981; and Hem 1975).
- Thus, neither observable mineral assemolages and/or redox couples are sufficient to indicate that site redox conditions are chemically reducing and not chemically oxidizing.
Finally, argument (c) suggests that hydrothermal experiments reported by Jantzen (1933) support the existence of a redox potential of -0.4 volts at Hanford (which coincides with the calculated values).
This low value was achieved by using finely crushed basalt and deoxygenated and deonized water.
However, in the same series of experiments by Jantzen (1983) runs with basalt chunks and simulated site groundwater produced redox conditions of only about
-0.2 volts (which coincide with the lower bound ~of the measured corditions).
Furtner, tne Siting Guicelines (960.3-1-5, p. 47757) preclude taking credit for enoineering measures, such as those simulated by reactions with crushed basalt and distilled water, to overpower less advantageous site conditions (i.e. chemically oxidi:ing vs. chemically reducing conditions).
Therefore, these particiuar experimental results are not a basis for suggesting that site redox conditions are as reducing as -0.3 volts, or are not chemically oxidizing.
Concerning point (2), the draft EA has assumes that the redox conditions at the Hanford site will reduce virtually all redox sensitive radionuclides to their least soluable and most sorptive state.
However, Eh cannot be treated as a master variable, because it cannot be assumed that all recox sensitive elements will be in chemical equilibrium within the system (Stumm, 1966, Lindberg and Runnels, 1984, Hostettler, 1984).
Therefore, even if redox conditions are established, it does not follow that redox sensitive radionuclides will be reduced to their least mobile state.
This concern is further supported by experiments that show that several redox sensitive radionuclides exist in their more oxidized state under " reducing" conditions of -0.3 volts and lower (Kelmers,1984; and Meyer, et al.,1984).
The question of whether the redox data support an evaluation that the reference repository has chemically reducing conditions that will maintain radionuclides in tneir least mootle state is critically important support for craf t EA findings concerning geochemistry favorable condition 960.4-2-2(b)(2) ("...
conditions that promote the precipitation.., or sorption of radionuclides,
.)
and 960.4-2-2(b)(4) (the dissolution rate of the radionuclide inventory); and potentially adverse condition 96G.4-2-2(c)(3) (conditions that are n'ot
)
chemically oxidizing); and associated geochemical modeling.
The finding on favorable condition 960.4-2-2(b)(2) is based on assumptions of low radionuclide i
solubilities and high sorption.
The finding on favorable condition 960.4-2-2(b)(4) is based on assumptions of low radionuclide solubilities.
The DOE finding on adverse condition 960.4-2-2(c)(3) is based on the assumotion that site redox conditions are not chemically oxidizing.
Use of less optimistic results could have a significant ef fect on findings for each of
)
3 j
76 9
l 4
these conditions, and thus could have a significant impact on the overall
)
qualifying condition (960.4-2-2(a)] for geochemistry.
]
l The NRC/ Staff considers that existing redox data are insufficient for a i
j conclusive or clear evaluation of site redox conditions and reactions; or to j
support the associated assumption that those redox conditions are etenically j
reactive and thus predetermine that radionuclides will be present in their r
i least mobile state.
However, the draf t EA states (page 6-4,13 and 7-3,13) l that in the absence of clear or conclusive support, findings are to be based or j
"... existing data and conservative assumptions..." Under this approach, 00E needs to reconsider data on site redox conditions and reactions as well as the
)
l findings on the geochemical favorable and potentially adverse conditions discussed in the previous paragrapn, anc the overall qualifying condition for j
geochemistry.
i 6-34 Section 6.3.1.2.11, Conclusions, ca;e 6-97, caragrach 1/ bullet 1, 2, and 3 j
Evidence does not conclusively support the " highly sorptive" characteristics of the alteration phases of the basalt for radionuclides, the reducing capacity of I
the basalt environment, or the dissolution rate of the radionuclide inventory.
)
According to Barney (1981), Ames and McGarrah (1981) and Salter et al. (1981),
the sorption of radionuclides is highly dependent on their oxidation state i
f (i.e., reduced species = high sorption, oxidi:ed species = low sorption), and I
the availability of sorptive minerals (see detailed comments 6-25 and 6-26).
However, " reducing" conditions do not necessarily lead to low steady-state l
radionuclide concentrations and high sorotion (see detailed comment 6-33).
t Further, not all clay mineral alteration phases are highly sorptive (see I
detailed comments 6-27).
Finally, the indication that less than 0.001 percent I
per year of the total radionuclide inventory will dissolve from a repository in
}
casalt is hignly dependent on tne reducing capacity of tne casalt system (i.e.,
j that radionuclides will be released in a reduced state); this has not been i
conclusively established (see detailed comment 6-28).
The assumption that j
radionuclides will be released in their more sorptive, less soluble state leads j
to low steacy-state concentrations anc calculations of icw racionuclice release.
(
i l
4 j
6-35 Section 6.3.1.3.5, Potentially adverse condition, oage 6-100, caragraoh 7 The draft EA states that potentially adverse condition 960.4-2-3 (c)(1) is not i
present at the Hanford site.
This adverse condition deals with technology being reasonably available for the construction, operation, and closure of the l
j repository to ensure saste containment or isolation.
However, with regard to shaft sealing requirements, the discussion does not support a conclusion about i
~.
i 77 i
e the absence of this adverse condition.
Discussion on pages 6-104 through 6-106 i
regarding the emplacement procedure for long-term seals system during repository closure does not address:
(1) The procedures for replacement of operational grout between shaf t liner annulus with long term sealant; and 4
(2) the durability of long term sealants.
The repository shafts and the voids, joints, and fractures around them will i
require adequate sealing over the long-term because they are potential pathways for radionuclide release to aquifers and the accessible environment. The i
i repository shaft itself could possibly be adequately backfilled to retard l
radionuclide migration.
However, the interface between the shaft liner and the rock wall, and the voids, joints and fractures in the rock around the shafts must also be sealed effectively with a durable sealant.
The performance of the long term seals may depend on how completely the sealant has replaced the j
I operational grout between the snaf t liner and the wall rock.
j i
These points should be considered in the final EA.
l I
Such consideration might include discussions on (1) sealing procedures, (2)
~
sealing materials and their long-term properties, and (3) testing and i
monitoring procedures to verify long-term performance of seals.
6-36 1
Section 6.3.1.3.5, Potentially adverse condition, eage 6-106, caragraoh 1 It is stated in the draft EA that the hydraulic conductivity of the disturbed rock zone around the shafts would be reduced using a system of grout curtains l
and bulkheads constructed from the shaft interior.
These are to be constructed
]
using " grout curtain construction techniques similar to those used to improve i
rock foundations at di.m sites." For installation of the bulkhead, " portions of tne liner, tne liner-supporting grout, and tne damagec host rock liner grout interface would be re.1oved." Because of these additional activities associated with grouting it is not appropriate to relate grout curtain construction at dam 1
sites to grouting the disturbed rock zone around the shaf ts.
While, the basic technique of drilling holes and injecting grout in the disturbed rock zone may be similar to those at a dam site, the methods of adequately ensuring the horizontal flow of grout to effectively fill all void spaces, cracks and joints around the shafts (illustrated in Figure 6-4, Section 6.3.1.3.5, page 6-105) can be substantially different.
In addition, grouting of the disturbed rock zone will encounter unique problems associated with:
}
removal of the high strength steel liner and the liner-supporting grout; i
installation of the low permeability bulkhead; and the limited space to perform work.
Finally, the seal materials in the shaft are required to be durable over a long-term.
Such constraints are not required in the grouting of dam sites.
i i
l i
78 Effective sealing of the " disturbed rock IJne around the shaft is crucial because the :one can provide a potential cathway for radionuclide release to the accessible environment.
The possible need to utill:e a technology substantially different than that of grouting a dam site might be considered in drawing a conclusion about the potentially adverse condition 960.4-2-3(c)(1).
6-37 Section 6.3.1.3.7, Potentially adverse condition, page 6-109, paragraph 9 The draft EA states, "As credit is not presently taken for the isolation potential of the Cohassett flow dense interior, thermal-induced fracturing around the emplace-ent boreholes or emolacement rooms, therefore, would not adversely affect the projectec ability of the host rock to provide isolation".
Yet, on page 6-263, caragraon 1, the future option of taking partial credit is maintained.
If such credit is taken, thermal induced fracturing may affect the ability of the host rock to provice isolation.
Thermal-induced fracturing will influence the stability of the emplacement boreholes, and may also significantly affect container integrity and create pathways for radionuclides.
Evaluation of "not present" conclusion for ootentially adverse condition (960.4-2-3 (c)(3)) does not consider all the flow paths created by thermal induced fracturing around emplacement boreholes and rooms.
Therefore, it is suggested that the statement regarding thermal-induced fracturing and its impact on the ability of the host rock to provide isolation be expanded to discuss the potential travel paths for radionuclides.
6-38 Section 6.3.1.4, Climatic changes, oaoes 6-111 to 6-113 The principal assu1ption for the discussion of the impacts of climatic change is that the clima+.ic changes that took place during the Quarternary Period i
bound the extreme conditions expected over the next 10,000 years.
This assumption coes not appear to be adequately supportec in :nis section.
According to many authors (e.g., Imorte and Imbrie, 1979), tne atmospneric warming induced by increasing atmospheric concentrations of caroon dioxide will likely result in a " super-interglacial" period with a higher mean global temperature than that estimated during the last interglacial period (about 125,000 years before present) and which would last several thousand years.
I Eventually, the " super-interglacial" period would be overwhelmed by orbital-climate relationships.
It is suggested that the discussion of paleoclimate and climate cnange might be expanded to include this possible
" super-interglacial" period, particularly with respect to identification of comparable paleoclimates with mean global temperatures of acout 63*F (ccmoared to about 61*F estimated during the last interglacial period and observed at present).
79
~
6-39 Section 6.3.1.4.6, Potentially adverse condition, page 6-117 and 6-113, continuing earagrapn The draft Es states that the potentially adverse condition of significant hydrogeologic perturbations over the next 10,000 years due to climatic changes is not present.
This finding is supported in the draft EA with the following statements:
i o
"The climate of the Hanford Site region is not expected to significantly change over the next 10,000 years.
Thus, the present ground water flow system is expected to remain relatively unaffected."
o "Proglacial catastrophic flooding.... appears to be the most probable disruction scenario associated with climatic changes tnat could affect the hydrologic system.
There is little chance of significantly renewed glaciation in the State of Washington in the next 10,000 years."
o "The very short transient nature of catastrophic floods....is such that significant long-tern ef fects at the repository ceotn are not expected."
The draf t EA finding is not wholly consistent with geologic and paleoclimatic studies of the Holocene Epocn in the Pacific Northwest.
Large-scale floods of the magnitude of the Late Pleistocane events are not likely to recur during the next 10,000 years and thus would not be excected to be a factor in influencing j
the gechydrologic system.
Those spectacular flooding events were indirectly caused by late growth and ablation of the continental Cordilleran Ice Sheet.
However, smaller scale pulsations of alpine and valley glaciation in response i
to climatic cnanges coulc significantly alter tne hycraulic cnaracteristics ano discharges of the Columbia and its tributaries. Aggradational processes may ensue with the possibility of invoking river channel migrations over the next 10,000 years. The occurrence of future channel displacements within the area of tne Hanford Reservation coulc cramatically alter regional patterns of reenarge and discharge and could significantly change flux conditions within local basalt and interbed aquifers of the Pasco Basin.
I Channel diversions may also be caused by other means.
The reach of the Columota that is located east of Gable mountain is susceptible to impoundment and diversion snould future block slumpage occur in bluffs on the eastern side of the river. Areas of particular concern are located in sections 11 and 14 of T. 13 N. and R. 27 E.
(Newcomo, et al., 1972).
Apart frem the potentially significant effects of channel migrations, the hydrologic regime at the Pasco Basin could be affected in more suotle ways by periodic episodes of cooler and moister climates.
Such episodes may be
80 expected to alter areak patterns of recharge and discharge.
Infiltration rates (recharge) would likely increase due to the cumulative ef fects of lowered evaporation rates and increased amounts of precipitation.
For example, local recharge in the Pasco Basin is presently considered to be greatest on the margins of the basin in structurally high and deformed zones of exposed basalt, especially anticlinal areas (draf t EA, page 3-78). However, coupled effects of increased precipitation and reduced evaporation may substantially increase the proportion of total recharge that occurs within the larger, structurally low areas of the Pasco Basin.
Significant changes have taken place ir the course of the Columbia River over the last 10,000 years.
This was an erosional period in which the alluvial system incised the glaciofluvial sediments deposited earlier, creating riverbank terraces.
It is evident that significant meandering of the Columbia took place along the reacnes tnat occur in the northern part of the reservation.
One paleochannel is south of Gable Mountain within the Cold Creek Syncline along the 460 ft topographic contour (Newcomb, et al., 1972). West l
Lake, the only natural (water-table) lake recorted within the reservation, occurs in a low area along this old channel.
The presence of a major channel 1
of the Columbia within the Cold Creek Syncline would have significantly altered i
regional patterns of recharge and discharge.
This would likely have changed flux conditions within the basalt and interbed aquifers of the Cold Creek l
Syncline.
The present-day channels of the Columbia near the site are relatively stable, aided largely by the presence of numerous reservoirs to the north that were constructed for the purposes of flood control, irrigation and hydroelectric power generation.
These engineering projects allow substantial regulation of discharge rates and reduce the susoended sediment load of the Columbia to a minimum.
These reservoirs provide engineered controls that cannot be presumed to remain in existence on a scale of millenia.
Based on present-day topographic contours, it appears that reaches of the Columbia River located within the Hanford Reservation would be susceptible in varying degrees to channel migration should aggradational processes ensue over the next 10,000 years.
Those lower reaches of the Yakima River that occur northwest of and adjacent to Richlanc are also susceptible to migration on tnis time scale.
A return to conditions of highly variable seasonal and yearly discharges and sediment loads may take place over the next 10,000 years.
In particular, a large increase in discharges and bedloads could be caused by t9e future ablation of reactivated alpine and valley glaciers.
An aggradational period may ensue, creating conditions which would favor the meandering of channels.
Glaciers which presently occur in the northern headwaters of the Columbia would expand in size given cooler and moister conditions favorable to growth. Only small-scale temperature changes would be needed to initiate the growth of alpine glaciers that presently exist in the northern headwaters of the Columbia.
,w
,n--
m-
---m y
w -
81 Paleoclimatic evidence from palynological investigations suggests that significant changes in average temoeratures and precipitation levels may have occurred since the relatively recent retreat of the Cordilleran Ice Sheet late in the Pleistocene Epoch.
For eastern Washington, three intervals within the post glacial period have been interpreted as being cooler and moister than today's climate:
13,000 - 10,000 yrs. B.P.
Nickmann (1979) 7,800 - 6,700 yrs. B.P.
Nickmann and Lecpold (1980) 4,100 -
125 yrs. B.P.
Nickmann (1979)
The most recent interval shown above is somewhat controversial. Mack, et al.
(1978) conclude from data collectec at a site in nortneastern Washington tnat there is no evidence of a shift to conditions cooler and moister than today during the period from about 5000 yrs. B.P. to Present.
The apparent cooling trend from 7800-6700 yrs. B.P. was first reported by Nickmann and Leccold (1930), wno speculate snat an unconformity may exist for tre same time interval at previously studied sites.
This interval, if verified, is significant because it appears to interrupt the Hypsithermal (ca 9,000-3,000 yrs. S.D.)
period which generally is considered to have been warmer and drier than at present.
While future temperature fluctuations can be exoected, climatologists are not in agreement as to the short-term or long-term direction of climatic change (i.e., cooling or warming), or even whether clearly discernable trends exists.
This is the result of an extremely complex interaction of natural-and human-induced variables which include but are not limited to the following:
Natural carameters volcanic injection of atmospheric dust area and curation of snow and ice cover in tne northern nemisonere atmospheric and oceanic circulation patterns (changes in temperatures, precipitation, evapotranspiration, and cloud cover) orbital characteristics (or elements) of the Earth variations in solar insolation alteration, retentiun, or release of atmospheric components by the biosphere (marine and terrestrial)
Human-induced parameters carbon dioxide production through the burning of fossil fuels deforestation
82 i
release of fluorocaroons thermonuclear devices sunlight reflection from jet contrails The likely long-term effects of human-induced changes are presently unknown.
The potential for these changes to either accelerate or retard the onset of the next major climatic cooling stage is also dependent on the future duration of human industrial and technologic activities and on the relative ability of the biosphere to partially compensate for transient atmospheric changes.
It would appear to be appropriate for the evaluation of expected geohycro'ogic changes caused by climatic variations over the next 10,000 years to be based on conservative assumptions. A conservative approach could involve evaluating tne likely effects of future cooling and warming trends, both of which have the' potential to change ground-water fluxes within the pasco Basin by the large-scale alteration of amounts snc patterns of ground-water recharge.
Based on the above analyses, 00E could then re-evaluate the finding on the potentially adverse condition.
i 6-40 Section 6.3.1.7.2, Evaluation crecess, eage 6-127, caragraoh 2 This part of the draf t EA does not fully consider or reference published geophysical information about geophysical anomalies.
This item states that
" interpretation of geophysical anomalies in the area of the reference repository location are ongoing." Geophysical anomalies may be geologic i
structures such as faults or may represent such things as data processing preolems. Ho.,ever, cue to otner evicence suggesting faults, it is possible that many of the geophysical anomalies do represent faults (see detailed comment 3-11). The existence of faults may impact conditions:
960.4-2-1 (b)(1), 960.4-2-1(b)(4)(ii), 960.4-2-7(b), 960.4-2-7(c)(3), 960.4-2-7(c)(6).
It is suggestec :na :ne final EA state wnat geopnysical anomalies are Oeing investigated, where they are located, that they have already been interpreted as faults in several instances (Long and Davidson, 1981, and Emerald Exploration and what the potential significance is to the reference repository location in terms of ground water flow and ground motion.
6-41 l
Section 6.3.1.7.3, Favorable condition, oace 6-127 and 6-123, paracrapn 1 The draft EA presents a favorable finding for condition 960.4-2-7(b) by using long-term, low average deformation rates to indicate that tectonic processes
83 such as faulting will-not adversely affect waste isolation for 10,000 years after closure.
However, the Rattlesnake Wallula Alignment (RAW), a significant fault :one (115 to 140 km long) with Quaternary movement deemed capable of a large magnitude earthquake (6.5M,) has been omitted from consideration in this section (NUREG-0309).
This emission makes the preliminary finding for condition 960.4-2-7(b) in the draft EA questionable.
Rattlesnake-Wallula Alignment (RAW), a northwest to southeast trending :one, is part of the Cle Elum-Wallula deformed belt (CLEW), a 40 kilometer (25 mile) wide :ane that has a northwest to southeast trending trace from Cle Elum, Washington, southeast to the Blue Mountains, a length of about 200 kilometers (125 miles) (draft EA, page 3-52).
RAW is the southern part of CLEW, and extends from Rattlesnake Hills - Umtanum Ridge to the southern termination of tne Wallula f ault (NUREG-0892 and NUREG-0309).
The Cle Elum-Wallula deformed belt coincides with the central one third of a tocographic lineament termed tne Olympic Wallowa Lineament (CWL)
(Rh0-BWI-ST-4).
The Olymoic Wallowa Lineament (CWL) extends for 640 kilometers (400 miles) in length, from the Straits of Juan de Fuca in northwestern Washington to the Wallowa Mountains in northeastern Oregon.
The structural significance of CWL, if any, remains controversial but CWL has been postulated to have regional tectonic significance (RHO-BWI-ST-4).
Although the structural significance of CWL is controversial, Davis,1982, notes that the existence of a disturbed plateau structural :ene (including the Wallula fault zone) coincident with tne central third of OWL cannot be questioned (i.e., CLEW).
Kienle, 1977, states that the Yakima Folc Belt is generally only gently folded except along CLEW where the deformation is more intense.
The increased intensity of structural ceformation witnin CLEW is believed due to the greater relative moeility of the crust (Barrash, et al.,
1983).
Several faults occur within and at the boundaries of the CLEW zone of deformation (NUREG-0309).
The overall tectonic nature of RAW remains uncertain, h0 wever, much of its length is typified by faulting.
Several faults have been eacped along the northeastern lime of Rattlesnake Mountain (Fecht, 1984).
In addition, the soutneast extension of tne Rattlesnake Mountain aeromagnetic lineament procaoly expresses faulting along much of tne RAW (RHO-BWI-ST-4). At least one basalt exposure has fault breccia up to 1000 feet wide along RAW (RHO-BWI-ST-4).
Quaternary surface faults exist along RAW (NUREG-0309).
The local seismicity of RAW is indicated by the microearthquake swarm in the northern area of Rattlesnake Mountain and other swarms in the soutneastern part of tre Rattlesnake Mountain area (50-EWI-TI-247).
As shown ey Fecht, 1984, in report 50-BWI-TI-247, Figure 5-4, these and other recent events produce an apparent vertical alignment which approximates the RAW and c:uld indicate fault movement along this trend.
An earthquake (M 3-3.5) occurred on :ne edge of g
tne southwest corner of the repository (50-EWI-TI-247, figure 5-1).
Inis is l
wnere RAW may pass along the aoruct western terminous of vakima Riege.
\\
l 84 RAW may begin where Umtanum and Yakima Ridge anticlines plunge abruptly below the basin sediments (NUREG-0892 and NUREG-0309).
Laubscher, 1981, indicates that RAW joins CLEW in the vicinity of the eas,: end of Yakima Ridge.
Many refe-ences place the north end of RAW near the north face of Rattlesnake Mountain. At this time the possibility that RAW e>tends even further to the northwest than Umtanum Rioge has not been ruled out.
The NRC staff previously postulated in NUREG 0309 and NUREG 0892 that RAW may range in length from 115 to 140 kilometers and the north end of RAW may begin from Umtanum Ridge to Rattlesnake Hills.
For the purposes of earthquake magnitude calculations, a total length of 120 kilometers for RAW was used by the NRC staff. Unfortunately, the rock in the area between eastern Umtanum Ridge and Rattlesnake Mountain is virtually unexposed (RHO-BWI-ST-4, Geologic Maps) and direct observation of the northern extent of RAW is crecluded.
The rock in the area northwest of Umtanum Ridge up to Sentinel Gap is also largely unexposed (RHO-BWI-ST-4, Geologic Maps).
The eastern tocographic surface excression of Yakima Ridge terminates abructly along the northwest projection of RAW and the termination is likely due to a nortnwest trencing fault (Cochran, 1982).
Faulting was also proposed as an explanation for the linear escarpment and structural displacement of east Yakima Ridge (Kienle, 1977) and (Band, et al., 1978).
The postulated northwest trending fault might (according to RHO-BWI-ST-4) be associated with a northwest continuation of the Rattlesnake Mountain fault, or other faults along RAW, through the nortneast corner of Snively Basin.
Further, it is indicated in RHO-BWI-ST-4 that Rattlesnake Mountain fault is probably related to faulting along much of RAW.
According to the draft EA, cage 3-51, paragraoh 2. the same northwest trending fault along east Yakima Ridge could explain the down-droppec offset of the Benson Ranch syncline betweeen Yakima Ridge and Rattlesnake Mountain.
The postulated fault also approximates the Cold P. reek hydrologic barrier (draft EA, Figure 3-1).
Rattlesnake Sorings exists wr ere tne postulatec nortnwest extension of RAW fault intersects a known east west fault along the southern flank of Yakima Ridge.
This postulated northwest extent of RAW is less than a mile west of the reference repository location.
The northwest trending postulated fault is laceled as a major structure in document RHO-BWI-ST-14, Figure 8-3, and is shown to be connectec to a major structure corresponding to RAW along the base of Rattlesnake Hills.
This connection suggests that the northwest trending major structure is the northern segment of RAW.
Such a relationship is supported by a pronounced aeromagnetic lineament extending from the eastern ends of Umtanum and Yakima Ridges and continuing alcng the entire trace of RAW (RHO-BW-ST-19P).
The significance of separating RAW from the northern segment of CLEW is that RAW is considered " capable" of fault movement under the criteria of NRC's Reactor Site Criteria,10 CFR 100, Appendix A but CLEW is not currently considered " capable" north of RAW using 10 CFR 100, Appendix A.
However, the
L t
85 1
Siting Criteria for Otsposal of High-Level Radioactive Wastes in Geologic Repositories are different and are under 10 CFR 60 Section 60,122.
In evaluating a site for high level waste disposal using 10 CFR 60, all of CLEW may be significant in evaluating potentially' adverse conditions.
1 A significant result of ground motion or of existing faults along the CLEW / RAW zone of influence could be the existence of or changes in groundwater flow paths.
Increased vertical flow could be caused by disruption of relatively impervious clay fillings in the prolific, vertically oriented cooling joints of i]
the basalt (see joint spacings in the draf t EA, on Table 6-16, page 6-166).
Additional information on the effects of structure on groundwater are in detailed comment 6-49.
It is suggested that the proximity and imoact of CLEW and RAW on waste isolation and design be reconsicered, in view of :ne information discussec above, and revision be mace to tnis section of the EA as appropriate.
i 1
6-42 Section 6.3.1.7.3, Favorable condition, oage 6-127, Paragrach 4 l
Available data on deformation rates has not been adeouately considered.
This finding of the draft EA is based largely on the occurrence of deformation at j
long-term low average long rates since the Miocene.
Statements about long-term Iow average deformation rates since the Miocene are also on the following pages i
in the draft EA:
6-128, paragraph 1; 6-129, paragraph 3; 6-130, paragraph 1; 6-130, paragraph 2; 6-131, paragraph 1; 6-132, paragraph 2; 6-135, paragraph 4; 6-137, paragraph 1; 6-210, caragraph 5: and 6-214, paragraph 4 The NRC staff's concerns with the view that deformation has been at long-term low 4
I average rates since the Miocene are in detailed comment 2-5.
An adequate basis I
for finding a favorable condition regarding the potential impacts of future deformation does not appear to nave been presented in this section of the draft i
EA.
6-43 Section 6.3.1.7.3, Favorable condition, page 6-128, caragraoh 3 The text refers to the results of a Delphi analysis that is of little importance to the favorable condition being assessed because this analysis did not consider faulting. Jointing and faulting are the most likely deformations to occur during the 10,000 year period of consideration.
The Delphi analysis i
tested the judgment of experts on the question of whether the present pattern and style of deformation that exists in the Pasco Basin will continue.
The i
data base for their judgments was derived from deformation based on fold growth, without considering the effects of fault displacement.
The final EA might consider the effects of faults on ongoing deformation.
Such analysis i
i i
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. -=
I i
86 l:
(
could affect the following conditions:
960.4-2-7(b), 960.4-2-7(c)(3),
960.4-2-7(c)(6), 960.4-2-7(d), 960.5-2-11(c)(1), (c)(3), 960.5-2-11(d) and 960.4-2-1(b)(1).
I i
l 6-44 t'
Section 6.3.1.7.4, Potentially adverse condition, page 6-129, paragraon 3 I
This section of the draft EA does not consider available information that i
indicates significant synclinal deformation (see detailed comments 3-11 and 3-13). This section states:
" Deformation appears to be concentrated on the steeper limbs of anticlinal folds with little or no deformation occuring in synclinal troughs like the Cold Creek syncline." Statements suggesting synclinal stability are also on :ne following pages:
6-130, paragrapn 1; anc 6-136, paragraph 3.
The Cold Creek Syncline is the area where the proposed J
repository is to be located.
Evicence indicates the possibility of deformation j
in this syncline, and tnis is imoortant to assessing the following conditions-960.4-2-1(c)(1), 960.4-2-7(b),(c)(3), (6)(d), 960.5-2-11(c)(11) (c)(3).
It is suggested the EA be revised to descride known and inferred synclinal deformation.
l 6-45 Section 6.3.1.7.4, potentially adverse conditon, oage 6-129, paragraoh 4 i
This part of the draft EA does not appear to consider the available, relevant information.
It states:
"No faults have been identified in the reference i
repository location." However, significant evidence for faults exists (see i
detailed comment 3-11). The existence of faults is important to assessing j
conditions:
960.4-2-1(b)(1), (b)(4)(ii), 960.4-2-7(b), (c)(3),(c)(6), and 960. 5-2-11( c)( 3).
1 Statements in the draft EA, suggesting that the reference repository is located l
away from faults and structures also apoear on the following pages:
3-79, paragrapn 2; 6-136, paragrapn 3; anc 6-21a, paragrapn 1.
It is suggested tnat l
i the EA be revised to qualify these statements by recognizing that interpreted i
faults have been identified and other evidence of shearing displacement is indicated by the presence of " tectonic breccia" in all deep boreholes in the l
reference repository location and in all other deep boreholes in the Cold Creek i
syncline (RHO-EWI-ST-14).
i 6-46 Section 6.3.1.7.5, Potentially adverse condition, oage 6-130, paragraph 6 i
f i
,----n-._
,nn_---.n_,.,,-.,,.-,-_
,--..n
-,_.-,----r, w-
87
~
The finding for this potentially adverse condition is based on an unsupported statement that a large (magnitude and acceleration not specified) historical earthquake is not expected to affect waste containment or isolation.
Also, the finding involves two incomplete applications of the potentially adverse condition because the guideline condition specifies the " geologic setting," not just the reference repository location, and calls for consideration of
" historical earthquakes," not just a singular large historical earthquake.
Due to evidence associating microearthquake swarm activity with the Cold Creek syncline (see detailed comment 3-15 and the paragraph below), there is no reason to believe that micro-earthquake swarms are unlikely to occur in the reference repository location over the next 10,000 years.
The affects of micro earthquake swarms on waste containment or isolation are not addressed.
Since 1969, swarm microearthquakes in the Pasco Basin nave occurred at Wooded Island (15 miles S.E. of the RRL) at Coyote Rapids (5 miles N of tne RRL), and Rattlesnake Hills (3 miles south of the RRL).
The Wooced Island swarm is associated with synclinal structure because this swar:r area occurs alcng ne mapped (dashed as inferred) Cold Creek syncline axis (RHC-SW-ST-19P). The Coyote Rapics svarm occurs on the mapped (dashed as inferred) axis of the Wahluke syncline (RH0-SW-ST-19P).
Adecuate consideration of historical earthquakes in the geologic setting might affect assessment of this condition 960 4-2-7(c)(1).
It is suggested this section of the craft EA be revised to provide an analysis of the effects of microearthquakes in the geologic setting on waste containment and isolation.
6-47 Section 6.3.1.7.5. Potentially adverse condition, eage 6-130, caragraph 1 Not considerec in tne seismic cesign for the site are tne effects of small earthquakes occurring within the geological repository operations area (GROA).
The most common mode of seismic activity observed in the Pasco Basin vicinity, since the installation of a relatively close-spaced network of stations in 1969, is tne release of seismic energy by microeartnquake swarms.
These swarms have been observed (Malone, et.al, 1975) to occur at very shallow depths, nearly to ne surface, and on multiple-inferred fault planes. Although no swarms have occurred entirely within the RRL, no analysis is presented in the draft EA on the possibility of such swarms in the future.
Since the centers of energy release in a microearthquake swarm are not precluced from occurring at repository depth, special consideration should be given to the effects of source acctierations (tens to a few hundreds of meters) near to the underground repository structures.
Many seismologists and geophysicists currently believe that at or very near the ructure surface peak accelerations become essentially independent of earthquake magnitude (Amoraseys, 1969, 1973, 1978; Brune, 1979,; Dietrien, 1973; Trifunac, 1973;
88 i
Jennings and Guzman, 1975; Hanks and Johnson, 1976; Bolt, 1978; Midortkawa and Kabayashi,1978; Seekins and Hanks,1978; Hanks,1979; Aki and Richarcs,1980; Hadley and Helmberger, 1980; McGarr, 1981; McGarr, et al, 1981).
In the very near source region where magnitude be:omes a less important factor in characterizing the ground motion, the state of stress and the aoility of the rock to store energy prior to failure during an earthquake become important factors.
l I
McGarr, 1984, has recently considered the effect of stress regime and depth on ground motion at very small distances from underground structures and has found that near-source accelerations in compressive regimes, such as is present in the Pasco Basin, may exceed near source accelerations in extensional regimes by i
as much has a factor of 3.
He also proposed an upper bound surface acceleration of 1.9g very near the source for events in a compressive regime, with significantly higner accelerations at depth.
Matters such as these might be considered in the final EA in an assessment of the possible effects of microearthquake swarms in the GRCA.
i f
6-48 aection 6.3.1.7.6, potentially adverse condition, oace 6-131 caracraohs 6 4
anc 7, page 6-132, caragrach 3 i
The finding does not appear to take into consideration:
t 1.
The nature of CLEW / RAW (see detailed comment 6-41) i 2.
That long-term, average deformation rates since the Miocene are not likey j
to be indicative of episodic ranges of deformation rates.
3.
Inat small eartnquakes co not occur only on small faults.
l I
4.
A preliminary analysis of plate tectonics processes in the vicinity of the Yakima Fold Belt and Columbia Plateau.
5.
The possibility that there may be recently active faults at Toppenish Ridge (Campbell and Bentley, 1981);
6.
The applicability or nonapplicability of the possibility that the seismological and geological methods may yield different results on earthquake frequency.
(For example the evaluations of Schwart: and Coppersmith in 1984 suggest that the historical seismological record may underestimate earthquake frequency and potential for large earthquakes.
Considerations such as listed above could impact the finding.
It is suggested that items 1 through 6 above be considered in this section of the final EA.
l
s 89 6-49 Section 6.3.1.7.9, Potentially adverse conditirn, oage 6-135, caraoraoh 3 This section of the draft EA finds that over the next 10,000 years tectonic l
deformations are not expected to adversely affect the regional groundwater flow system. The NRC staff considers that the potential for faulting (see detailed comments 2-5, 3-11 and 6-41) to have with possible adverse impacts on regional groundwater flow makes the preliminary finding on conditions 960 4-2-7(c)(6) in the draft EA questionable.
The draft EA states that leakage along structural discontinuities is a factor r
in regional recharge to deep basalts (page 3-79).
The draft EA recognizes the oossibility that Yakima Fold Belt areas like the Cold Creek syncline may be i
crossed by strike-siip faults with linear extents of tens of kilometers, and i
these may hydraulically connect flow systems or form flow barriers (page 3-89).
Possible vertical groundwater exchange along known and inferred structures is recogni:ed in the draft EA. Umtanum Ridge-Gable Mountain anticline may play a role in vertical groundwater mixing (draft EA, page 3-82).
It should be noted that this structure has been found to have Quaternary movement (see detailed comment 3-9).
The Cold Creek barrier is believed to be a structural discontinuity, and although its exact nature is undefined it acaears to align with a possible northwest extension of RAW (see detailed comment 6-41).
Hydrochemical data suggest deep groundwaters are mixing vertically with shallow grounewaters at an undefined rate (page 3-90) along the Cold Creek barrier.
In summary, the information cited above indicates potential faulting or other tectonic deformations could adversely affect the regional groundwater flow system.
It is suggested that this finding be reexamined after consideration of the information cited above has been documented.
6-50 Section 6.3.1.7.5, Potentially adverse condition, eage 6-131, bullet 3 This section of the draft EA implies that microearthquake swarms are limited to the marginal area of the Pasco Basin.
This is of questionable accuracy. The three Pasco Basin swarms mentioned in this section are all located well within the boundaries of the Pasco Basin and are appropriately refered to as being in l
l the central Pasco Basin.
This is important because the Pasco Basin is the basin where the reference repository is located and understanding the seismic potential of this basin may affect the EA assessments of tectonic stability.
In addition, microearthquake swarm events have occurred astride the northern boundry of the RRL and in the middle and, southern part of the RRL (see detailed comment 3-15).
It is suggested that this section of the EA be revised to provide and evaluate the microearthquake swarm locations that are in the Pasco Basin.
l 90 i
6-51 Section 6.3.1.7.10, Disqualifying condition, eage 6-136, paragraph 3 This section of the draft EA does not appear to consider the available information relevant to condition 960.4-2-7(d).
This section of the Draft EA 1
Indicates that the RRL was sited away from areas of known or suspected faulting. Also, it is stated that little or no deformation has occurred in i
synclinal troughs and that rupture planes from small earthquakes are not expected to laad to a loss of waste isolation. Small earthquakes do not necessarily occur only on small faults (see detailed comment 2-5).
Other detailed comments are made on faulting in and near the RRL (see detailed comments 3-11 and 6-41) and on synclinal structures (see detailed comment 3-13).
possible imoacts on ground-water conditions are discussed in detailed comment 6-49.
It is suggested that consideration of the points brought out in the detailed comments referenced above and this comment, be considered in evaluation of the finding for this disqualifying condition as presented in the final EA.
6-52 Section 6.3.1.8. Qualifyinc condition, page 6-137, paragraoh 3 The 00E does not consider structural hydrocarbon traps formed by steeply dipping faults, such as that which may exist along the southeastern corner of the repository (sae detailed comment 6-41), as well as possible others within a
l the repository itself.
Potential traps other than anticlines could include feeder dikes. Although such dikes are reportedly found only south and east of the site where exposures allow their detection, numerous others, like the Ice Harbor dike near Pasco (USGS, 1979), may lie buried beneath the repository area.
In addition, (RHO-BWI-ST-19P) reports that magnetotelluric results indicate that the basalt doesn't reflect the basement structure and there is great relief on the pre-casalt surface.
Consequently, the lack of surficial anticlines does not necessarily imply the absence of deeper structural targets within the Cold Creek syncline. Althougn such structures are hidden from conventional geophysical methods, the November, 1984 issue of the American Association of Petroleum Geologists Exolorer credits the current exploratton " boom" on the Columbia Plateau to rapid technical advancements in magnetotelluric methods, cacable of detectirg structure beneath the basalts.
This is significant because loss of waste isolation could occur from 1
i exploratory drilling in or near the reference repository location.
It is suggested that this section of the final EA recognize that currently l
undetected sub-basalt anticlines may be found and that assessments be made for hydrocaroon traps other than anticlines.
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4 91 i
6-53 Section 6.3.1.8.3, Favorable condition, page 6-139, caragraph 2 No mention is made anywhere in Section 6.3.1.8.3 of the fact that ground-water samples from the Grande Ronde Basalt formation, Cohassett flow (" preferred candidate hori:en") are about 50 percent saturated with methane gas (page 6-187 of the draft EA). Only the Wanapum and Saddle Mountains basalt formations are i
discussed.
The Saddle Mountains and Wanapum Basalt are said to have methane l
from carbonaceous interbeds.
The Grand Ronde Basalt formation is not i
interbedded with terrestrial carbonaceous matter and methane is not indigenous to basalt rock (draft EA page 6-187).
The gas in the Grande Ronde formation may originate in sediments below the basalt.
This is supported by the presence of methane in sediments below the basalt found during exploration in the vicinity of tne Saddle Mountains (draft EA page 6-187).
Deep sources of methane make exploratory crilling through the Grande Ronde, the unit in wnicn waste emplacement is proposed, a possibility.
I Section 6.3.1.3.3 of the EA might be revised to consider that methane gas has been found in the Grande Ronde formation and that it may originate from belew-casalt sediments; and that there is a reasonable possibility for explcratory drilling through the repository host rock.
6-54 Section 6.3.1.8.3, Favorable condition, page 6-139 caracrach 4 This section of the draft EA does not adequately consider available information j
indicating methane gas exists in the reference repository location.
This section indicates that any hydrocarbons generated under the Pasco Basin should have migrated away from the synclinal area to the anticlinal ridges.
- However, this is not consistent with tne existence of metnane gas in grouncwater in tne Pasco Basin, Cold Creek syncline, reference repository location (Hydrochemical j
Oata Base, Jan., 1984). There are no sedimentary interceds in the Grande Ronde basalt which is the formation the reference repository is in.
Methane is not j
inciginous to basalt (page 6-137).
The gas may nave migrated from seciments below the basalt. 'This section indicates that the sedimentary sequence beneath the basalt is the hydrocaroon exploration target. Potential deep exploratory targets for gas below the Cold Creek Syncline impact human intrusion assessments for the Hanford site.
It is suggested that this section of the EA snould be revised to recognize and provide an interpretation for the existence of metnane gas in the Cohassett Flow (" preferred candidate norizon").
6-55 k
92 Section 6.3.1.8.3, Favorable condition, oage 6-139, caragraoh 4 This section of the draft EA indicates that the anticlinal ridges are hydrocarbon exploration targets and the nearest anticline to the RRL is Yakima Ridge listed as being 2 miles west. Actually, Yakima Ridge has a buried subsurface extension which is one half mile southeast of the reference repository location, (RHO-BWI-ST-14). According to the draft EA, overall groundwater flow is believed to be to the southeast (draft EA, page 3-80).
A potential hydrocarbon target structure this close to the reference repository location, along the overall groundwater flow path, is significant to human j
intrusion assessments.
It is suggested that this section of the EA be revised to recognize the proximity of the buried Yakima Ridge anticlinal structure.
i 6-56 Section 6.3.1.8.5, potentially adverse condition, oage 6-141 and 6-142 Available information is not adequately considered here.
A potentially adverse condition exists at a site if naturally occurring materials are present whether or not actually identified in such form that economic extraction is potentially feasible during the forseeable future.
The draft EA finds that this potentially adverse condition does not exist for Hanford.
Unmentioned in this section is methane that occurs in the reference repository location at repository depths, from an unidentified source.
The lack of analysis regarding methane in the reference repository location seriously impedes assessment of this condition.
It is suggested that this l
section of the EA be revised to include information indicating the cresence of methane in the reference repository location. Af ter this information is included, the finding should be reconsidered.
6-57 Section 6.3.1.8.9, Potentially adverse condition. cage 6-143, last caragraph The 00E states that the potentially adverse condition regarding impacts of forseeable human activities on the ground-water flow system could be present.
This appears to conflict with the finding on draft EA page 6-76 regarding expected changes in geohydrologic conditions.
(See detailed comment 6-18).
The final EA should resolve this apparent disparity in findings under the relevant guidelines.
6-58 Section 6.3.1.8.11, Ot soualifying condition, page 6-145, caragraoh 5
!41 I
(
93 This part of the draft EA makes a statement of questionable accuracy.
It states that natural gas is not present within the vicinity of the RRL. ' Methane (CH. ) is a natural gas that occurs in the RRL at repository depths (Hydro-chemistry Data Base, Jan. 1984). The possibflity for exploration because methane gas exists within the vicinity ofLthe; reference repository location should be documented in this section becau'se it may affect the assessment, fit is suggested that the statement referenced above be recansidered.
6-59 i
Section 6.3.2.3, Conclusion on qualifying condition, oage 6-149, caragraph 1/ bullet 3 Preliminary performance results, which suggest that [ basalt has the capacity to isolate radionuclides, are based on insuf ficient dati ahd ' optimistic assumptions. Based on inconclusive theoretical' calculations of redox conditions; in the absence of data on the kinetics of tne exoecteo recox reactions; and without discussion of the reducing capacity of the' basalt / water system, it is assumed that radionuclides are released in their least soluble, most sorptive state (see detailed comments 6-25.and 6-33).
Performance,
assessments based on such assumptions are likely to lead to underestimates of j
radionuclide releases to the accessible environment.
)
6-60 Section 6.3.2.3, Conclusion on qualifying condition, eage 6'-149, caragraph 1 i
The conclusion on the system guideline (960.4-1; section 6.3.2.3) appears to be inconsistent with tha conclusion on the potentially adverse condition concerning human ac+1vities affecting the ground water flow system I
(960.4-2-8-1(c)(5); section 6.3.1.8.9).
The corclusion en the system guideline states that the system is unlikely to be altered unfavorably by human-induced events or processes (bullet 4); however, section 6.3.1.8.9 states that the potentially adverse condition of human activity adversely changing the ground-water flow system could be present at the site.
This apparent inconsistency should be resolv'ed in;;he final EA.
i 1
6-61 This comment was incorporated elsewhere in the comment package.
6-62
/
Section6.3.3.1.5,Potenti'aIlyadvesecondition,page. 6-151-Section 6.3.3.3.4, Favoracle condition, eage 6-205
\\'/
i e
f
,,) 1 7,
t
94 The draft EA concludes -that surface facilities will be located in areas subject to only minor and infrequent flooding and that this flooding can be mitigated during repository construction and operation.
Based on this conclusion, the
' draft EA finds that (1) surface characteristics that could lead to the flooding of surface facilities are not present at the site (Potentially Adverse Condition 960.5-2-8) and (2) there is the absence of surface water systems that could potentially cause flooding of the repository (Favorable condition 960.5-2-10).
Review of the draft EA and supporting flood analyses (Skaggs and Walters, 1981) i presented in the draft EA indicates that the information presented is not adequate to support the conclusions; the draft EA acknowledges that a potential for site flooding exists and tnat engineering measures will be required for 4
flood protection. The draf t EA bases its 'indings with resoect to the guicelines on tne acility to implement flood protection measures wnich mitigate flood effects.
The guicelines, however, address the question of site flooding, rather than the feasibility of engineering measures to control flooding.
Hence, it. appears that consideration of potential flooding 'of surface o
facilities at tnis site may alter the conclusion that the favorable condition is present and that the unfavorable condition is not present.
The final EA should either reconsider the findings associated with these guidelines, or support the conclusions with further documentation and analyses that clearly show that site flooding will not occur.
6-63 Section 6.3.3.2.3, Favorable conditions, page 6-157, paragraoh 3 The draft EA claims that favorable condition, 960.5-2-9 (b)(1) is present.
This favorable condition deals with the host rock being sufficiently thick and laterally extensive to allow significant flexibility in selecting the depth, configuration, and location of uncarground facility.
Altnougn the cata presented in the draft EA indicate that the preferred candidate horizon (Cohassett flow) thickness exceeds the 21 meter minimum thickness criterion stated on page 6-154, the discussion on pages 6-153 to 6-157 appears to be misleacing because of tne following reasons:
(1)
In stating that the Coh4ssett flow provides more than twice the minimum thickness (21 meters or 70 feet) necessary to construct the repository, the draft EA assumes that the. entire dense interior is suitable for repository construction. A 00E sponsored study by Long and WCC (1984, page I-52) appears to discredit'this assumption with the following statements:
"The entire dense interior of the Cohassett flow also was not considered because of the laterally continuous vesicular :ene, which is considered to be avoidable during repository construction.
Thus it was deemed acpropriate to compare only the tnickness of the lower
i
[, -
i p.
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95 dense interior of the Cohassett flow to the thickness of dense r
i interior of the other candidate horizons."
4
)
Furthermore, Long and WCC (1984, page II-19) states that "the repository l
panel area would always be sited in the dense interior below the internal vesicular zone."
(2) The draft EA takes credit.for the ability to exercise the " option to select from three other candidate horizons (Rocky Coulee, McCoy Canyon, j
and Umtanum flows)". Because of this option, a claim is made on "further flexibility" in selecting a host rock horizon at depth.
This claim may 4
i not be appropriate especially since on page 6-157, paragraph 3, the draft EA states that "...these flows do not appear to have sufficient minimum i
thickness...".
The thickness of the host rock has an impact on the findings for 00E Siting i
Guidelines 960.5-2-9(b)(1) and 960.5-2-9(c)(1).
3 j
The final EA should include a discussion as to whether or not construction within the vesicular zone will be necessary in evaluating the 00E Siting Guidelines 950.5-2-9(b)(1).
i 6-64 l
Section 6.3.3.2.4, Favorable condition, oage 6-169, caragraph 1 j
The draft EA states, "When the effect of thermal-induced stresses were included j
in the Barton analysis..... the supoort requirements did not increase j
significantly." However, the draft EA does not include a discussion on the decreased performance of the rock bolts due to the increased thermal load.
An increase in the temperature in the waste emplacement rooms will increase the thermal stresses resulting in a larger support requirement.
Furthermore, an increase in temperature may significantly reduce the strength of concrete and resin grouted rock bolts. Research on resin grouted rock bolts indicates that they are not suitable for use above 212*F.
Similar research on concrete and I
concrete grouted rock bolts indicates that the differences in thermal expansion of the colt, rock and grout may cause the bond between the rock and the bolt to be broken (Kendorski, 1984).
The draft EA concludes that favorable condition, 960.5-2-9 (b)(2) is not j-present at the reference repository location, however, ground control problems 1
associated with the presence of a high thermal load might still be j
appropriately evaluated in the final EA.
6-65 i
J J
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._._._._.,___,,-_,y
,_.,.--,.,.-_._,y,
96 Section 6.3.3.2.6.1, Shaft construction, oage 6-173, paragraph 4 For the feasibility of blind-hole drilling, the draft EA cites three factors, one of which is the experience gained from other blind-hole drilling projects with constraints similar to those at the reference repository location (Table 6-20). A review of Table 6-20 indicates a potential problem with this statement, in that, the geologic conditions and/or dimensions of the shaf ts in the examples are very different to those planned at Hanford.
The problem is illustrated by examples of: the Agnew shaf t, where drilling of a 14-foot diameter shaft was stopped far short of the projected 3,378-foot depth due to equipment failure (page 6-179, paragraph 4); and the Amchitka shaft, where the total drilled depth was 6,150 feet, but the shaf t diameter was only 7.5 feet.
It is evident that the drilling method to be utilt:ed at Hanford would involve different geologic and drilling parameters (such as drill rig torque requirements, size of drill pipe, drilling mud requirements, bottom hole cleaning procedures, aquifer conditions, and effect of the in situ stresses) than those in the cited case h.istories.
Case history examples presented in the draft EA do not substantiate the view that engineering measures beyond reasonably available technology are not needed for construction of shaf ts as stated in the DOE Siting Guideline 960.5-2-9 (c)(2).
It is suggested that drilling clans discussed in Morrison-Knudsen, Co., Inc.,1984, be included in the final EA, such that the uncertainties associated with and the feasibility of drilling the shafts at Hanford can be evaluated.
6-66 Section 6.3.3.2.6.1, Shaft construction, page 6-175, caragraoh 3 The draft EA states, "...hign degree of success in drilling small-diameter boreholes en the Hanford site is a positive indication that drillability, hydrologic conditions, and stability concerns can be managed in excavating exploratory and repository shafts." While it is accepted that the geologic and nydrologic conditions encountered in drilling would oe tne same for small-diameter boreholes (3 to 17 incnes) and large-diameter shaf ts, the assumption that their influence on drillability would be same is questionable.
Case histories of drilling small-diameter boreholes cannot be cited as evidence of large-diameter shaft constructibility.
For example, a large-diameter snaft would:
intersect a greater number of fractures; encounter a larger volume of water inflow; and require drilling equipment with considerably larger capacity for drilling than small diameter boreholes.
An increase in the number of fractures intersected by shaf ts increased the probability of rock spalling or sloughing.
Furthermore, Morrison-Knudsen (1985), in discussing Hanford, stated that it is difficult to predict the behavior of shaft walls based on information gathered during drilling of small diameter boreholes, i
97 The evidence presented in the draft EA concerning the success of drilling small-diameter boreholes should not be considered a basis for the "not present" conclusion on the 00E Siting Guideline 960.5-2-9 (c)(2).
6-67 i
Section 6.3.3.2.6.2, Construction of an underground facility, page 6-184, i
paragraphs 5 and 6 Tbis section of the draft EA refers to the provision for emergency pumps in the 1
shaft to provide the capability of removing " appropriate quantities of ground water."
It is not clear what is meant by an appropriate quantity of ground water.
The potential exists for high rates of inflow into the shaft upon penetration of high hydraulic conductivity flow toes.
The possibility also exists for encountering high hydraulic conductivity zones in the basalt flow 4
1 interiors due to structural discontinuities or other similar features.
The sixth paragraph on page 6-184 refers to the avoidance of large ground water inflows.
The methodology for avoiding potentially large ground water inflows is not described. A possible approach is to extend pilot drill holes in advance of drift development.
No discussion is included in the draft EA on temporal changes in inflow rates i
that might result from seismically-induced changes in head and/or hydraulic 4
conductivity.
Figure 3-24 on page 3-55 shows the magnitudes of relatively shallow (less than 4 km focal depth) earthquakes which occurred in the vicinity of the RRL from 1969 through March of 1983.
As described on page 3-54, paragraph 3, there have been areas of swarm-type seismic activity within 10 km of the reference repository location, including some events at focal depths of less than 2 km.
Given that the proposed repository would be constructed at a depth of approximately 1 km in relative lateral proximity to seismically active i
zones, it is prudent to consider and evaluate the potential effects of seismic events which could occur during the repository's operational period and may also occur during tne construction onase.
Refer to detailed comments 6-46 and 6-50.
6-68 Section 6.3.3.2.7, potentially adverse condition, page 6-191, paragraoh 3 i
The draft EA states that the presence of potentially adverse condition 960.5-2-9(c)(3) requiring extensive maintenance of underground openings during repository operation and closure is not expected.
This conclusion is not substantiated by the case histories presented on page 6-191, paragraph 5 of the draft EA.
Examples are presented in the draft EA of openings in basalt that require little maintenance.
However, these openings (Snoqualmie Falls turbine chambers and railroad tunnels) are at shallow depths wnere in situ stresses and
98 temperatures are much l wer than expected repository conditions.
Deep mines in
~
the Coeur d'Alene mining district are cited as requiring little support; however, in that region, displacement of rock in the shaft causes millions of dollars of damage per year to timber and shaft sets (Bues and Board,1984).
Also Barton's Q-system classifies the Cohassett dense interior rock mass as very poor to fair and the RMR system classifies the rock as fair to good (page 6-165). Therefore, neither the classification system, nor the examples given, appear to rule out the possibility of extensive maintenance of repository openings.
6-69 Section 6.3.3.2.7, o tentiallv adverse condition, cace 6-193. caracraoh 2 c
The draft EA states, "Many joint surfaces show only partial coatings of infill material with basalt-to-basalt contacts." This statement seems to be at variance from the statements made on cage 6-100, caragraph 6. and page 6-110, paragraph 8.
On pages 6-100 and 6-110, the host rock permeability is believed to be decreased by fracture sealing from hydrothermal alteration of minerals along the fractures. However, on oage 6-193, the basalt-to-basalt contact across joints, due to a lack of infilling, is believed to decrease the amount of movement along joints which reduces the need for continued maintenance.
The presence of fracture infilling, or the lack thereof, may have an impact on conclusions on the 00E Siting Guidelines 960.4-2-3 (b)(2) and 960.5-2-9 (c)(3).
It should be indicated whether most fractures are filled or not, and credit for either fracture sealing or reduced creep potential should be accordingly taken.
6-70 Section 6.3.3.2.8, Potentially adverse condition, pace 6-194. caragraph 2 The draf t EA acknowledges that potentially acverse condition 960.5-2-9 (:)(4) is present. However, it states tnat safety hazards or difficulty in retrieval can be handled by using " standard practices."
This assumption appears to be optimistic.
Retrieval of canisters after they have been in the repository for period of up to 50 years is not a " standard practice".
Procedures to reduce the radiological and safety hazards associated with retrieval will encounter unique problems associated with the following.
Thermal-induced fracturing, and hydration and dehydration of mineral components in the fractures is possible around waste emplacement boreholes.
This can cause water inflow which may turn to steam in
t I
99 4
~
the borehole and pose a threat to personnel safety during the retrieval operation.
i Container integrity could be jeopardized by rock failure, possibly l
resulting in breached containers and resulting radiologic hazards.
i i
6-71 Section 6.3.3.2.9, Potentially adverse condition, page 6-195, paragraph 2 4
The draft EA states that "... the flow tops above and below the Cohassett dense interior would be avoided during construction by monitoring the distance i
between the flow toos and excavation by means of explora*.ory drilling."
This could be a potentially dangerous procedure due to the high pressure fluids i
expected to be present in flow tops which would be encountered when crilling
)
from the drifts.
It is not clear how the distance will be monitored without j
drilling into the flow tops, i
4 6-72 Section 6.3.3.2.10. Disoualifying Condition, oage 6-197, paragraoh 2 The draft EA states, "While some water inflow into excavated openings is anticipated, the volumetric flow rate is expected to be minimal cased on current knowledge". The statement does not seem to be consistant with statements made in RKE/PB (1983).
)
RKE/PB (1983) states, "In the case of development seepage water, where flows up l
to 2500 gal / min (9460 1/ min) may be encountered...".
This statement suggests j
that substantial flow rates of incoming water are possible.
However, no
]
counding ranges for the quantity of water inflow are presented in craf t EA.
4 The possibility of substantial water inflow under high temperature and pressure raises serious implications on the conclusions regarding disqualifying condition 960.5-2-9(d).
It is suggested tnat the following topics ce discussec in this section:
the types of anomalies that may be encountered during repository construction and estimates of inflow that may result from each type, and I
i case histories to demonstrate that these magnitudes of water inflow under high pressure and temperature can be handled with available i
technology.
The problems associated with grouting and freezing in l
repository panels should be detailed.
l j
1 t
100 i
?
l 4
discussion of the kinds of available technology that would be used to j
mitigate reasonably expectable water problems.
1 l
6-73 l
This comment was incorporated elsewhere in the comment package.
6-74 This comment was incorporated elsewhere in the comment package.
1 l
6-75 j
Section 6.3.3.4.2, Evaluation process, page 6-210, caragraph 1 The subject paragraph states that "The adverse tectonic condition that could preclude development of a repository is that of an active fault (either l
seismically active or creeping)."
As outlined in detailed comment 6-41 a major seismogenic fault zone (i.e. RAW) likely exists within one mile of the repository.
Seismic reflection results suggest that faults which may represent portions of that zone may exist within the repository (50-BWI-TI-177).
In addition, many other faults have been interpreted within the repository detailed comment 3-11.
Unless the inter-preted faults are decoupled from the ongoing tectonic deformation of the pasco 1
Basin (detailed comment 2-5), they would be exoected to creep.
Consecuently, the evidence suggests that development of a repository at the currently planned location may be incompatible with the statement quoted above.
i i
6-76 4
i Section 6.3.3.4.2, Evaluation orocess, eages 6-209 210 This section does not adequately consider the available information about faulting and the seismic evaluation. Much of the subject section involves the potential impact of faulting and seismicity on repository design. According to EA page 2-41, most effects from fault rupture occur within 8 km of the fault l
and that underground design for such effects are generally difficult, so that active faults should be avoided by 8 km.
Detailed comment 6-41 summarizes substantial evidence to support the possible existence of a major active fault zone (RAW) less than a mile southwest of the reference repository location.
According to the 8 km criterion (draf t EA, p. 2-41), most effects of future movement on that fault would affect about two-thirds of the reference repository location.
i I
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1 1
101 f
I As outlined in detailed-comment 6-41, current tectonic activity corresponding to the postulated fault zone is indicated oy recent seismic activity. Given the length of the feature, it is ccasidered capable of generating a major 4
earthquake, potentially involving substantial fault rupture and shaking.
Such underground impacts might include roof falls, local ground shifts, disturbance of the clay fracture fillings of the prolific cooling joints (page 2-5, paragraph 2; see also joint spacings of Table 6-16, page 6-165) and displacement of shears or faults within the workings.
It is suggested that the
)'
potential effects of faults (including geophysically interpreted faults) in or near reference repository location be considered in the final EA.
i 6-77 1
Section 6.3.3.4.3, Favorable condition, oage 6-210, paragrapn 4 This favorable condition is met when the faulting and seismicity in the geologic setting of a site for geologic disoosal of nuclear waste are
~
significantly less than these generally allowable for nuclear facilities.
As 4
)
support for a finding that this condition is present, the draf t EA relies j
heavily on the existence of numerous nuclear facilities at Hanford since 1943.
i l
However, this favorable condition does not apoear to be adequately assessed.
The draft EA does not compare the magnitude and intensity of the seismicity in the geologic setting with the magnitude and intensity that is generally allowed
.I for the construction and operation of nuclear facilities.
The comparison of nuclear power plan WNP-2 at Hanford to some west coast plants (draf t EA, p.
6-211) is not as comprehensive as comparisons made at other sites, such as at Richten Dome.
For example, the draft EA for Richton Dome apparently considers data from all licensed nuclear power plants in the U.S. (draft EA, Richton Dome, p. 6-146). The design requirements for a waste repository may not 4
reflect those required for nuclear power plants.
The design requirements of structures important to safety will comply with 10CFR60 and appropriate EPA regulations.
It is suggested this section include estimates of seismic magnitudes and intensities in the geologic setting, such as directly along RAW, and snow tnese estimates are significantly less than generally allowable for the construction and operation of nuclear facilities.
i i
6-78 Section 6.3.3.4.5, Potentially adverse condition, oage 6-212, caragraoh 3 This section of the draft EA does not consider all applicable data. This i
section states that the potentially adverse condition of high accelerations at the reference repository location is not present because of the low to moderate seismicity of the Columbia Plateau. Campbell and Bentley (1981) have mapped a 1
t j
L
+
4-1 J
i 102 j
Holocene age :ene of scarps 32 km in length on one of the Yakima Folds, i
Toppenish Ridge.
Using the relationships of Slemmons and others (1982) and Bonilla (1984) for rupture length versus magnitude, the causative event could have been about Magnitude 7.2.
McGarr (1984) suggests that an event this si:e would have a considerable volume on both sides of the fault plane that would
{
experience accelerations in excess of one g.
It is suggested that consideration be given to:
(1) the data of Campbell and Bentley (1931), (2) f the calculations of McGarr (1984), and (3) the possibility of a large l
earthquake near the site (e.g., along RAW, the Horse Heaven Hills structure, or the Saddle Mountains).
]
6-79 l
1
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Section 6.3.3.4.5, potentially acverse condition, oage 6-212, paragrach 5 i
)
Adequate consideration of available data is not given. This section states that subsurface facilities are generally not adversely affected by earthcuakes large enough to cause damage to surface facilities, that detrimental effects are noted only if the ructure intersects the underground opening, and that 1
earthquakes affect ground-water flow.
Earthquakes originating at several kilometers from a locality where surface and subsurface effects can be comcared, succort the first statement.
This is because the higher frecuency
]
portions of the ground motion spectre attenuate rapidly with distance away from j
the hypocenter.
Surface facilities are affected more by the relatively lower 1
frequency ground motion spectre that attenuate rapidly with distance away from the hypocenter.
l McGarr, et al., 1991, in a study of earthquakes and ground motion in a mine in South Africa measured high, very short duration acceleration pulses (up to a maximum of 12g) from earthquakes originating within a kilometer of the j
accelerometer.
These earthquakes with magnitudes less than M 1.5, did not j
cause significant damage to the mine workings even though they involved high j
acceleration pulses. However, an M 3.7 did cause substantial damage.
The L
geologic setting of the Hanford site has had a recorded M,4.4 event.
The j
largest event recordec within the pasco Basin, 13km from the reference repository, was M 4-4.5 (Fecht,1984), paragraph 4).
The subsurface conditions j
g 1
in South Africa are not expected to necessarily be closely analogous to the i
Hanford site but the basic concepts and findings of McGarr's work have l
significant implications for seismic ha:ard assessment.
It is suggested that magnitudes and accelerations which may occur in the i
immediate vicinity of the repository be assessed using analyses based on the larger events recorded since 1969.
6-80 Section 6.4.1.4.2 Analysis of releases under routine coerations,
(
page 6-222 tnrouan 6-224 4
103 The source term presented for routine operational releases is only one cf the source terms expected from the various operations indicated in the facility description, Section 5.1.
There are apt to be other source terms associated with cleaning and decontamination of shipping casks, with the handling of DHLW containers and TRU packages, with the processing of 17000 gallons per day of radioactive liquid wastes (Table 5-1), and with the management of the solid low-level radioactive wastes genersted on site.
Spent fuel when removed from the reactor has a layer of radioactive crud on its outer surfaces that provides a source term for fuel handling operations even if no leaky fuel pins are present.
Leaky fuel pins are present in most spent fuel pools and must also be i
l disposed of also, In the contamination found in spent fuel pool water the predominant radionuclides are usually Cesium-134, Cesium-137, Cobalt-58, Cobalt-60, and Rutnenium-106, depending upon the history of the spent fuel and the pool water.
It is suggested that the final EA present an assessment that considers the source terms originating in the varicus cleaning, handling, packaging, and processing coerations that might be conducted tr the Waste Handling and Packaging Facility, the exce:ted emissions after cleanup in the HVAC and any other gaseous waste handling systems, and the resulting radiological imoacts in the environment (NUREG-0695).
6-81 Section 6.4.2,'Postclosure guideline analysis:
A preliminary system performance assessment, oages 6-226 thrauch 6-288 The 00E may not have fully assessed the second half of the postclosure system guideline (960.4-1) which states that "the site will allow for the use of engineered barriers."
In places, the draft EA appears not to address the possible effects of the natural system on components of the engineered carrier.
These components include tne waste package (see detailed comments 5-4, 6-1, 6-95, and 6-109); the packing (see detailed comment 6-94); the grouting (see detailed comment 4-2); and the general repository design (see detailed comment 3-11).
The final EA, the 00E snould consider in more specific terms, the manner by which the site allows for engineered carriers.
6-82 This comment was incorporated elsewhere in the comment package.
6-83 Section 6.4.2.1, Scope and objectives, oage 6-227/6-228, continuing caragraph
104 A probabilistic. approach requires either an extensive data base that is large enough so that realistic distributions of the data can be observed, or a limited, but quality data base; that, according to a consensus of expert opinion, appropriately bounds expected geochemical conditions / reactions.
(See detailed comment 6-90.)
6-84 Section 6.4.2.2.1 Waste package subsystem description, page 6-229, paragraph 2 The Hanford Site draft EA does not discuss the site's ability to limit releases for the alternate waste form of commercial high-level waste.
Instead, only releases from spent fuel are discussed.
Figure 6-8, oage 6-190, of the Deaf Smitn County Site draft EA snows that tne commercial hign-level waste form coulo well be hotter after emplacement than the spent fuel waste form.
Although, a full assessment of commercial high-level waste form may be inapprocriate at this time, an initial comcarison with the scent fuel waste form would make the Hanford Site EA more complete and more easily compared to the salt sites.
6-35 Section 6.4.2.2.1, Waste packages subsystem description, page 6-229, paragrach 4 The main function of the packing surrounding a waste container, as defined in this section accears to be inconsistant with material presented in Section 5.1.
This section (6.4.2.2.1) suggests that packing is needed for " maintaining reducing (i.e., low Eh) conditions in which many radionuclides have low solubilities..." draft EA Section 5.1.4.3.1 (page 5-38 paragraph 1) maintains that packing material is recuired for"... controlling ground water Eh..."
This is an important distinction, for the latter suggests that the packing is imposing redox conditions on the system that are different than
" ambient," and thus imposing low radionuclide solubilities on release calculations.
6-86 Section 6.4.2.3, Subsystem performance assessment, eages 6-232 to 6-237 and 6-242 to 6-243 This section of the draf t EA summarizes subsystem performance assessment for the Hanford repository using a probabilistic approach and models referenced in several Hanford documents.
The degree of conservatism suggested in the draft EA is not supported by the data. Assumptions for the analysis are listed in p.
6-233 with the suggestion of conservatism cecause the assessment leads to:
t 105
"(1) in underestimation of container lifetime, (2) on overestimation of the amount and (or) rate of radionuclide release
- rom the engineered barrier system, and (3) an underestimation of groundwater travel time."
Conservatism is also suggested to be present in the container failure analysis based on generalized corrosion because of the fol;owing three f actors (pp.
6-242 to 6-243):
The container is assumed to fail when 7.5 centimeters (3 inches) of the wall thickness nas correced.
The factor of limited oxygen supply available in the naste package subsystem has not been considered.
The corrosion calculation did not take credit for the corrosion resistence provided by the oxide film formed in the air steam environment."
The overall conservatism of waste package analysis is not supported by all the available data. Available data which have not been given adecuate consideration include data on (1) redox / reducing environment, (2) localized corrosion, and (3) packing stability.
These are discussed in comments on performance of the packing (detailed comment 6-94); waste package environment (detailed comment 6-93); and use of the uniform corrosion equation (detailed comment 6-95).
The significance of inadequate consideration of these factors could mean that the degree of conservatism suggested may not be present. As as example, the draft EA container failure criterion is based on the wall thickness (0.8 cm) corresponding to axisymmetric yield.
A cylindrical container sucject to i
external pressure will normally ' ail prior to this by non-axisymmetric elastic buckling (Gill, 1970).
Using the Von Mises equation, elastic instability of the spent fuel container is predicted to occur after 7.2 cm of corrosion, f.e.,
a wall thickness of 1.1 cm.
Also, discontinuity anc weld stresses co not appear to be taken into account in the draf t EA.
These could cause failure near the maximum allowable stresses corresponding to a wall thickness of 2.2 cm.
The DOE should reconsider the degree of tenservatism claimed with respect to the uncertainties in the data for repository environmental conditions and waste package failure modes.
6-87
106 l
Section 6.4.2.3, Subsystem performance assessment, eage 6-233, continutna paragraon 1
1 This list only indicates those items for which' credit was not taken in the I
performance analysis fo the systems.
The list should also present those processes, conditions and assumptions for which credit is taken.
For example, based on inconclusive estimations of redox conditions and, in the absence of data on the reducing capacity of the basalt / water system, it is assumed that radionuclides are released in their least soluble, most sorptive state and credit (unstated) was, therefore, taken for low redox conditions and reactions.
Performance assessments based on such assumptions are likely to lead to underestimations of radionuclide releases to the accessible environment (see i
detailed comments 6-28 and 6-33).
6-88 Sectien 6.4.2.3. Suosystem ee for anca assessment, eage 6-233 ftem 3. butlet 2 The draft EA states that the fact tnat the system performance assessment does not take credit for the effects of matrix diffusion on radionuclide transport leads either to an overestimation of the amount and (or) the rate of radionuclide release from the engineered barrier system, or an underestimation of ground water travel time.
Matrix diffusion acts as a retardation mechanism relative to the velocity of radionuclides in individual fractures. However, the hydraulic conductivities calculated in the draft EA are applied as an average over the hydrostratigrachic unit or fractured interval, and not to individual fractures.
The effective porosity interpreted from field tracer tests which consider the medium as a porous continuum adjusts the calculated linear fluid velocity and account for fracture flow velocities.
However, the expected value of effective porosity assumed in the draft EA in tne modeling analyses does not correspond with the value derived from the Hanford site tracer tests.
Therefore, the statement in the draft EA that censideration of matrix dif fusion would decrease the release rate of radionuclides fron the total isolation system does not j
appear appropriate cecause tne ground water velocity calculated oy tne 00E l
using their assumed effective porosity distribution would not correspond to the velocity in individual fractures.
6-89 Section 6.4.2.3.1, Stochastic analysis methodology, pages_6-234 to 6-235 The methodology for waste package performance assessment places great empnasis on a single failure mode of a single barrier, f.e., general corrosion of the overpack.
In the belief that the overpack will provide containment for an expected 6100 years and a minimum of 5000 years, the waste package assessment I
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107 i
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j methodology is greatby simplifted.
As a result some analyses have been omitted.
These are discussed in this comment.
l 3
l No analysis is done for delays in basalt resaturation time, for packing i
penetration time, or for penetration of fuel rod cladding (or glass form j
dissolution). Not accounting for the time resulting from these delays could be regarded as reasonable if the overpack could, by itself, provide all the i
j containment needed.
However, the overpack 11fetime estimates provided by the l
1 Hanford draft EA may not be supportable.
They are based on purely empirical equations derived from limited experimental data.
i I
The omission of other failure modes (e.g., pitting and crevice corrosion,-
j corrosion in the Air / steam environment human intrusion, earthquakes, etc.)
j makes the analysis inadeouate to support confidence in the results of the l
i calculations.
In particular, it does not consider early failure (e.g., initial flaws, human intrusion, and earthquakes).
These modes have low occurrence probabilities but potentially severe consequences and should not be eliminated without a satisfactory assessment.
An assessment methodology is needed which can incorporate all f ailure modes j
relevant to a given barrier in a systematic, unified procedure for assessing 1
that barrier. Moreover, the assessment methodology should be capable of j
integrating the individual barrier cerformances into an overall waste package t
evaluation.
The overall evaluation should take into account the multibarrier i
redundancy of the package and the protection offered inner barriers by the
[
l outer barriers and the possible deleterious effects of barrier interactions.
{
I Once a satisfactory waste package assessment methodology has been developed,
]
waste oackage lifetimes should be calculated including uncertainty analysis of I
the predictions.
The results of such calculations should be reconciled with the 960.4-1(a) Postclosure Guideline that reoutres that the site be amenable to the use of engineered barriers.
6-90 1
Section 6.4.2.3.1 Steenastic analysis metnecology, cage 6-235 l
]
The preliminary performance analysis in the draft EA uses relatively new 9
computer codes and process models (e.g., Corrosion Model (Fish-1983),
CHAINT-MC, MAGNUM-MC, REPSTAT, and EPASTAT) that have not been validated.
This is acknowledged in the draft EA.
However, it is not possible to perform l
technically thorough checks on the results given in the draft EA without validating the codes against equally complex engineering problems and having the codes available for independent use.
It is suggested that documentation of the computer codes /models and of validation studies be released for use by i
others for independent evaluation.
1 1
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t
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6-91 l
Section 6.4.2.3.2. Identification of radionuclides used in performance assessment pages 6-235 througn 6-237 In the Hanford draft EA, the method used in the screening procedure to select radionuclides used in the performance assessment is based on the initial 1
inventory, the half-life, solubility, and the adsorption of radionuclides.
There is no present requirement that the treatments of this subject in the EA i
be consistent with requirements in 10 CFR 60 in controlled release, but such l
consistency will be necessary at such time Hanford may be under licensing I
consideration.
In the first stee of the screening crecedure, " radionuclides with inventory fractions of 1.0 percent or less were eliminated from further consideratton."
"... because radionuclides with inventory fractions of less than 1.0 percent are unlikely to contribute significantly to the total release...."
This i
criterion is contrary to that set by 10 CFR 60.113(a)(fi)(2) which states that the one part in 100,000 per year release requirement "does not apply to any radionuclide which is released at a rate less than 0.1*. of the calculated total release rate limit."
It is suggested that results of analysis be discussed in the final EA to illustrate that the "1.0 percent or less criterion" does not comoromise the criterion set by 10 CFR 60,113(a)(ii)(B).
In the second step of the screening procedure, nuclides with half-lives of less than 100 years are omitted from consideration since the inventory at
~I3 approximately 5000 years will be less than 10 percent of its initial inventory.
This assumption fails to consider the uncertainties in containment time and the potential for breach of containment at snorter times (i.e., 300 years).
In the third stec, radionuclides with Icw solubility are assumed to contribute insignificantly to cumulative release.
The same criterion of less than or equal to 1.0 percent is again used.
The substantial uncertaintly in the environment (see detailed comment 6-93) will impact the solubility assumed.
4 The potential existence of transcortable colloids that can migrate througn a porous packing material (see detailed comment 6-96) could nave a substantial impact on meeting the radionuclides release limits.
Similarly, organo-complexes formed from organic materials in the bentonite may have enhanced solubility.
In the fourth step, adsorption of radionuclides by packing is assumed to increase radionuclide travel times and reduce radionuclide release, t.arge l
uncertainties in the properties of packing material and the waste package environment across the waste package boundary are discussed in detailed comments 6-93 and 6-94 In particular, there are no experimental data for the proposed compressed backfill of 75*. basalt and 25% bentonite.
Also, the use of data from dilute solutions may not apply near the edge of the waste form where many nuclide solution concentrations are expected to be near their solubility 4
e 109 limits (see detailed comment 6-96).
If this is the case, the solid may approach saturation and adsorb a smaller fraction of nuclides from solutions (Salter, 1984) and therefore, retardation is decreased and transport is faster (Pescatore,1984).
Selection of radionuclides for performance assessment is a crucial step in the process of arriving at the Level-3 finding for the 960.4-1(a) Postelosure Guideline, with regard to demonstrating for the reference waste package design that the site is amenable to the use of engineered barriers.
The final EA, should consider a discussion of these issues in relation to the Postclosure System Guideline 960.4-1.
6-92 Section 6.4.2.3.2, Identification of radionuclides used in performance assessment. page 6-237, and paragraph 2 and 3 The radionuclide solubility and sorption values are for the " expected" redox conditions (-0.3 volts) (Salter and Jacobs,1983).
The use of -0.3 volts as the expected condition when modeling radionuclide transport predetermines that radionuclides will be in a less soluble more sorptive state.
Low radionuclides solubilities are apt to lead to low calculations of release and faulty conclusions concerning the determination of radionuclides of concern.
6-93 Section 6.4.2.3.3. Waste oackage subsystem cerformance. eaces 6-239 to 6-273 Waste package Environment: Uncertainty in Near Field Conditions: The interaction between the waste package and its immediate environment affects the lifetime of the containment carrier and the rate of radionuclide release from the engineered barrier system.
During the pre-closure period there is a potential for high temperature, oxic conditions to prevail.
The effects of these pre-closure conditions on waste package performance are not discussed in the craft EA.
It is not clear how uncertainty in tnese conditions are accounted for in Hanfords's waste package subsystem performance analysis.
During post-closure, temperature and radiation effects can alter the nature of the immediate package environment. Work done by Gause (1984) and Wood (RHO-BW-ST-21P, 1982) indicate that changes could occur around the package or in the packing material as a result of temperature and irradiation. While some work (Wood, et al.,1983) has indicated the reducing nature of basalt environment in that oxygen will quickly be removed from the basalt waters, this work did not include the effects of radiolysis which will generate oxidants.
Calculations have been done to predict the time-temperature profiles for a waste package in basalt (RHO-BWI-ST-18,1981). In this work, it has been noted
110 1,
that the predtetion of wa'ste package teinceratures, which are sensitive to tne a
thermal conductivity of packing materiais, shnuld include a coupling of heat and moisture flow within the packing and tne very near field basalt.
Because j
such a coupling was not considered, there are uncertainties in the predicted temperatures and, therefore, in the anticipated performance of barrier materials, especially in light of the recent change in packing material design (i.e., the use of preformed annular shaped packing).
Radiolysis effects can potentially enhance or restrict corrosion of the carbon steel container.
Alpha-radiolysis can result in oxidizing conditions and lower pH and increased radionuclide solubility (Pederson, 1984).
The formation of hydrogen in radiolysis can lead to hydrogen assisted failure of the container.
The formation of large molecular weight organics from radiolysis of CH4 present in the groundwater (Nel son, J. L.,1934; BNL-NUREG-34220,1934; Gause, E. P.,
1934) may also affect radionuclide solubility and transport.
No estimates of :ne radiatien dose rates with time and distance have been given 7
for a basalt recository. A recent estimate of the dose rate at the surface of the carbon steel overpack in a salt repository (Jansen, G., 1984) is almost two l
orders of magnitude lower than that estimated in an earlier study i
(AE50-TME-3131,1982). Uncertainties of this magnitude combined with uncertainties in the temperature could be magnified as uncertainties in the performance of tne carrier materials.
A discussion of the anticipated waste package environment, uncertainties in the environment and how these affect the performance of the ccntainment barrier and release from the engineered barrier system would be appropriate in the final EA.
6-94 Section 6.4.2.3.3, Waste cackage subsystem performance, page 6-238 Performance and Uncertainties in the Performance of the Packing Material:
Altnougn tne draf t EA states tnat no credit is taken for radionuclide transport or adsorption in the packing, tne waste package subsystem performance conisders (see page 6-229, last paragraph on the main function of packing) that tne packing makes a positive contribution to the waste package lifetime and the l
retardation of the transport of radionuclides.
There is evidence, however, that makes the packing's contribution questionable.
In particular, chemical degradation of the packing through hydrothermal diagenesis, aging, selectivt dissolution or interaction with components of the groundwater may alter the ability of the packing material to perform as anticipated.
This could detrimentally affect the container lifetime and releases from the package (NUREG/CR-2482, ENL-NUREG 51494, Vol 4, 1983).
It is known that bentonite undergoes alteration to illite, a non-swelling clay, l
at relatively low temperatures (Pusch,1933; Eberl,1978), although the rates 1
111 may be slow.
Of greater significance is the observation by Couture (1934) that, in the presence of steam, alteration to a non-swelling form occurs rapidly.
Most Hanford tests to date have involved basalt / water and bentonite / water systems and little attention has been paid to precompacted basalt / bentonite packing annuli which are be used in the current waste package design.
If this packing is altered by steam, as shown by Couture (1984), the assumotion on which canister corrosion is based might be significantly different.
Similarly, the transport of radiochemical species will depend on the characteristics of the packing. A completely altered material would have a much larger hydraulic conductivity than an intact material.
In order to assure that the orecomoacted cacking does not detrimentally affect container corrosion and racionuclice release, pnysical properties sucn as swelling pressure, hydraulic and tnermal conductivity, etc., need to be quantified for the range of anticipated waste package conditions.
Such data may then be used in assessing the cerformance of the waste cackage with resoect to regulatory criteria.
It is recommended that the final EA acknowledges the uncertainties of the contribution, (cotn positive and negative) by the packing on waste package performance in the context discussed in this comment.
6-95 Section 6.4.2.3.3, Waste packace subsystem oerformance, cage 6-238 Use of Uniform Corrosion Ecuations:
The draft EA states that the corrosion model is tnat of Fisn anc Anantatmula (Fish, IS33).
This model is an empirical one, based on data (Westerman, 1994) recorded for experiments of a few weeks' duration under conditions that may not represent actual repository conditions.
The empirical coefficients are not related to any phenomenological model.
The validity of using this model to extrapolate short-term results to hundreds of years is of question.
The model of Fish and Anantatmula is actually two madeis, one for oxidizing and one for reducing conditiors, and the draf t EA does not state wnich of the two is used.
Furtnermore, tne data on anien tne model is casec is unusual in :nat at hign temperature (250C) the corrosion rate is lower tnan it is at low temperature (125C). The applicability of this phenomena in the repository is unknown, because of the lack of defensible mechanism to account for it and the uncertainty of the repository environment and to what extent different conditions would alter the observations.
There are basic problems with the approach used in this draft EA to assess time to failure of the waste package due to container corrosion. Although a range of corrosion rates are used to generate a probability distribution function (pdf) of canister 14 fetime, this range is not exolicitly dependent on the relevant corrosion conditions such as pH and Eh, That is, there is no phenomenological modeling.
Instead, the influence of pH and En are assumed to
112 be incorporated into the range of corrosion rates.
The influence of radiation is incorporated by multiplying the corrosion rate by an unsupported empirical factor which is independent of the dose and decreases linearly with time from 1.75 to 1 after 300 years after resaturation. ' Finally, the temperature dependence is treated by assuming that corrosion proceeds at one rate above 125C and at another rate below 125C.
The high temperature dependence is roughly one-half the low temperature rate.
The shortcomings of this model are acknowledged in the document by Sagar (Sagar,1984) which supports the conclusions drawn in the EA.
There, it is suggested that the quantitative results of this model are preliminary in nature and subject to change as better data and models become available.
The fact that no phenomenological modeling of the observed corrosion results has been achieved makes the extrapolation of the rates to 1000 years and beyond suspect.
In the Fish and Anantatmula model, as applied by Anantatmula (1984),
the empirical relationship has a single parameter to which a 10 percent uncertainty is applied arbitrarily.
Because the corrosion equations are linear, whatever uncertainty.is assigned will translate into essentially the same percentage uncertainty in the lifetime.
Using different assumptions about the onset of corrosion, the rate of corrosion under different but plausible conditions, and the enhancement of corrosion under radiation, it might be possible to arrive at a failure time less than 1000 years, in which case quite different results would occur in the selection of radionuclides.
Because neither the environmental conditions and their potential variations, nor the corrosion rates and their uncertainties, nor the effects of radiation and its uncertainty, are stated and justified, the canister lifetime odf presented lacks justification.
A calculation of the canister Iffetime using the best available judgment of the impact of these effects and their uncertainties should be made and the results reconciled with 960.4-1(a)
Dostclosure Guideline that requires the site to be amenable to the use of engineered barriers.
In particular, the geochemical, redox, radiation environment, and the range of uncertainty in the corrosion rates implied by the potential variations in the conditions should be considered in the final EA.
6-96 Section 6.4.2.3.3, Waste package subsystem performance, eages 6-238 to 6-273 Uncertainties in Radionuclide Concentrations at Waste Package Interface:
The performance assessment for release rates and releases to the accessible environment assumes that the concentration of nuclides at the breached package will be solubility limited.
It is not clear how uncertainties related to solubility and the formation of colloids are accounted for.
Large uncertainties exist in the assumption of solubility limited release.
These uncertainties are due primarily to the uncertainties in the solubilities
(
i 113 s.
e i
of nuclides and uncertainty in the assumptien that only dissolved nuclides can i
be transported.
The solubility of an individual element will be affected by l
the character of the solid phase (Strickert, 1982), the presence of common ions, the pH (Rai, 1983; Ogard, 1981), the Eh (Pigford, 1983), the temperature, j
the presence of concentrated electrolytes and of radiolysis which may alter the oxidizing-reducing nature of the environment (Pederson,1984).
i l
Strickert and Rai (1982) measured the solubilities of two solid forms of Pu over a pH range from 4 to 8 and under oxidizing conditions.
Pu(OH)4 was found 4
to have a higher solubility than c.ystalline Pu0,and both forms exhibit a 2
i change in solubility of 3 orders of magnitude in the pH range investigated.
j Cleveland, et al. (1983) have recently reported solubilities for Pu and N, in basalt waters, that exceed those exhibitec in otner synthetic groundwaters, i
Solubilities for Americium are ambiguous (Ptgford,1982). Measured i
solubilities of Am vary over eignt orders of magnitude as the pH cnanges from l
approximately 9 to 6 (Rai, 1983). Ogard (1981) estimates that at pH 4 tne i
solubility of uranium in cetonizec water may vary 20 orcers of magnitude depending on whether conditions are oxidizing or reducing.
Neptunium, like i
uranium, exhibits a wide range in the solubilities depending on Eh and the (Pigford, 1982).
Phases may exist which exhibit crystallinity of solid Np02 j
retrograde solubilities and the presence of colloidal species may alter releases from the engineered barrier system.
It has been shown also that colloids may be formed during dissolution of the waste forms, whetner UO or glass (Olofsson,1981), and the colloids may not be 2
)
subject to adsorption in the same way tnat molecular species are (Bonano, 1984; Behrens, 1982).
It is known that uranium and other actinides can form soluble complexes with a variety of organic substances, including the organics that are present in the bentonite clay.
k In the final EA, a summary of current data on solubilities in the anticipated j
environment near the waste package and uncertainties in that data would be
~
useful.
The imoact of these uncertainties on controlled release rates should j
be evaluated.
The potential for radionuclide organo-complex and colloid formation should be addressed. The impact of radiolysis should be acknowledged an'd the solubility i
ranges used in the assessment should be reconciled with the uncertainties that l
would arise from this source in addition to.he lack of knowledge of solubility under known conditions.
There are currently no data which indicate the magnitude and uncertainty in the j
concentration of nuclides at the package interface under anticipated i
j conditions.
These conditions would include a degraded packing material,
)
corrosion products and temperatures between approximately 100*C and ambient
)
i repository temperatures.
Further testing should involve a documentation of i
this source term under conditions anticipated during the post containment
- period, l
114 6-97 Section 6.4.2.3.3, Waste package subsystem performance, pg. 6-238 and Table 6-28, eg. 6-249 Packing Transcort Parameters:
The transport of radionuclides to the accessible environment is controlled by groundwater flow and by adsorption in the packing and the host rock, as discussed in the draft EA.
However, the delay in reaching the accessible environment, as well as the quantity reaching it, are strongly dependent on the transport parameters assumed for the packing. This aspect of the assumption is not clearly discussed in the draft EA.
~12ms"1 and an apparent The draf t EA uses a hydraulic conductivity of 10 diffusion coefficient of 10-6,2 -1 These are stated to be assumed values c
3 although there are available experimental data.
In particular, Westsik and others (Westsik,1933) report a hydraulic conductivity of 7 x 10-12,3-1 for a hignly compact (cry density of 2.1 gem" ) 75-percent sand, 25-oercent centonite mixture.
It is reasonable to excect that a basalt / bentonite mixture would behave similarly. Given the uncertainty in the realistically achievable packing density during overpack emplacement, a hydraulic conductivity substan-tially greater than this value may occur.
Such larger values could result in substantial advective flow, contrary to the statement made in the draf t EA.
Similarly, Neretniecks (1977) and Tastenfelt (1982) have reported apparent diffusion coefficients for radionuclides as large as 3 x 10"# 2
-1 cm 3
, a value much greater than that used in the draft EA.
The increase in flow rate and the decrease in time to reach the host rock that could occur if these larger values of diffusion coefficient and hydraulic conductivity are used could alter the predicted performance of the packing in a major way.
The effect of these parameter uncertainties could lead to an expanded set of radionuclides that would require detailed consideration, particularly in view of detailed comment 6-94 on performance of the packing materi al.
These data should be considered in t e final EA.
To the extent possible, the effect of values for tne parameters discussed above and the uncertainties therein should be considered by COE and reconciled with the Level-3 finding for the 960.4-1(a) Postclosure System Guideline with regard to supporting, for the given reference waste package design, that the site is amenable to the use of engineered barriers.
6-98 Section 6.4.2.3.3, Waste oackage subsystem certormance, eage 6-247, Table 6-27 Values of adsorption coefficients used for technetium may ee too high, thus underestimating ne release of tecnnetium.
Tne COE, in cr.cosing tneir adsorption coefficients used for tecnnetium, cites results of experiments in
l f
115 i;
I k
l which hydra:ine was used to create a reducing environment (Salter et al.1981; i
Barney, 1981,1984).
These results may not be appitcable because a i
hydrazine-rich environment may be different from the repository environment.
Experiments do show that technetium may plate out on reduced ferrous material i
in the surrounding rock, but it is not known if such material would be present, j
Reactions between hydra:ine and solution, hydrazine and container walls, and hydra:ine and radionuclides have not been characterized.
Recent work by the l
NRC subcontractors (Kelmers, et al., others, 1984) suggests that sorption ratios (adsorption coefficients) measured in solutions containing hydrazine may be not representative.
(See detailed comment 6-25 and 6-33.)
In the final EA the experimental results that are available and their validity to site conditions when choosing adsorption coefficients snould be considered.
i j
6-99 Section 6.4.2.3.3. Waste cackage subsystem cerformance. cace 6-248, j
paragrach 1, and Section 6.4.2.3.a, Recository Seals Subsystem Performance, page 6-258, caragraon 2 4
1 The solubility values in Table 6-27 are different than the values in the cited j
reference'and are not readily traceable to their sources.
Some of the values may be non-conservative.
A footnote to Table 6-27 states:
"Taken from Salter and Jacobs (1933)." The reference Salter and Jacobs (1983), contains a tabulation of both expected and conservative values to be used for modeling activities. Many of the
" conservative" solubility values given in Salte-and Jacobs (1983) were stated j
to be experimentally measured solubilities; thus, there would seem to be little Justification for using solubility values which are lower than these
" conservative" nuncers.
The solubility values in the draft EA Table 6-27 are not in good agreement witn the values presented in Salter and Jacoes (1933) i
{
and, in some cases, are lower than the recommended conservative values, as shown below. Another footnote to Table 6-27 states that the solubility values J
were adjusted for the radionuclide fraction, but it is not clear what this means or now tne solubilities were computed.
Taole 6-2 c;mpares tne craft EA with Salter and Jacobs (1983).
l 1
ki I
d I
1 i
i i
i i
116 Table 6-2 Solubility (mol/L)
Draft EA Salter and Jacces (1983), Table 1 Table 6-27 Conservative Expected C-14 4.0E-6 to 4.0E-9 1.0E-3 1.0E-6 I-129 1.0E0 to 1.0E-2 1.0E0 1.0E-2 Np-237 1.0E-7 to 3.0E-9 1.0E-5 1.0E-10 Pu-239 1.2E-8 to 1.SE-11 Pu-240 6.0E-9 to 9.0E-12 Pu-242 2.0E-9 to 3.0E-12 Pu-total 2.0E-8 to 3.0E-11 1.0E-5 1.0E-9 Tc-99 5.0E-4 to 2.0E-8 1.0E-5 1.0E-9 Se-79 1.0E-4 to 1.0E-3 1.0E-3 1.0E-7 Sn-126 3.0E-6 to 3.0E-11 1.0E-5 1.0E-10
.-.y
e,
4 117 J
I As can be seen, the radlonuclide solubility values given in the draf t EA Table 6-27 are in several cases one or more orders of magnitude lower than the i
" conservative" solubility values recommended by Salter and Jacobs (1933).
Without an understanding of how'these data were " adjusted", they cannot be evaluated with respect to realism or conservatism.
6-100 Section 6.4.2.3.3, Was+.e package subsystem performance, page 6-256 i
Unsuoported Statement on Containment of Radionuclides by the Waste Package:
The draf t EA states (page 6-256), "It can ce qualitatively conclucec tnat the waste package can be designed to provice substantially complete containment of 4
the radionuclides for longer than 1000 years." Given the uncertainties in i
calculation of waste package lifetime and the limited state of knowledge j
regarding repository conditions and processes, this statement would appear to be unsubsta1tiated.
The major succort for this statement comes from the recort by Sagar (Sagar,1934) which states in its summary (Sagar,1994 Page t, 1st j
paragraph):
"The container corrosion model and site data used in applying the i
methodology described in this report are preliminary and are based on a small number of observations.
Therefore, the numerical results reported herein are l
not definitive of the final expected performance of the waste cackage subsystem.
Rather, the objective of the report is to present a methodology for performance assessment, and through application of this methodology, obtain an understanding of the parametric sensitivity."
At the present state of knowledge substantial uncertainties remain in various aspects of waste package performance.
It is suggested that any conclusionary i
statement, in the final EA, about waste package performance reflects the j
uncertainty.
6-101 4
Section 6.4.2.3.5, Site subsystem cerformance, pages 6-261 through 6-268 The detailed comments 6-11, 6-12, 6-15, 6-24, 6-102, 6-103, and 6-105 indicate 4
that a reasonable doubt exists concerning the reliability and applicability of the hydraulic property data and travel time estimates presented in the EA, Detailed comment 6-102 illustrates the sensitivity of the calculated travel times to variations in the assumptions and techniques of the hydrologic modeling.
This comment presents a parametric analysis which forms part of the basis for the NRC's questions regarding the validity of findings in the draft EA with respect to the pre-emplacement ground-water travel time favorable condition (expected travel time greater than 10,000 years along any path of likely radionuclide travel) and disoualifying condition (expected travel time less than 1,000 years along any path of likely and significant radionuclide 1
travel).
l
118 Detailed comment 6-12 discusses the results of previous the CCE-sponsored travel time estimates for the Hanford site.
Most of these estimates are deterministic in nature; a simple equation was used to calculate a ground water velocity based upon single input values of transmissivity, hydraulic gradient, and effective thickness.
This velocity was then divided into the distance along the flow path to the accessible environment to determine the desired travel time estimate.
This method does not provide any measure of the uncertainty associated with the travel time estimates.
The travel time presentation in the draft EA, based upon a two-dimensional modeling study (Clif ton, et al. (1983); Clif ton (1984); Clif ton, et al. (1984))
constitutes a departure from the previous studies; the hydrogeologic input parameters are treated as stochastic variables and travel time distributions are generated utilizing repeated operation of a numerical model.
The NRC staff consider that the stochastic approacn of tnese models is an improvement over the deterministic models with respect to their ability to impart an appreciation of the uncertainty in the travel time estimates. The stochastic l
models presented by in the draft EA are also intended to provide some estimate of the likely value of the pre-emplacement travel time based on current information, in addition to the evaluation of the uncertainty in the travel time. However, we have significant questions with respect to the formulation and operation of the models presented in the draf t EA, as well as the choices of oarameter inout values.
These cuestions raise doubt about the' accuracy and applicability of the estimates of median travel time presented in the draft EA.
l Problems associated with the formulation and operation of the travel time models presented in the draft EA are discussed in detailed comment 6-102.
In this comment, a simple analysis of the numerical results for median travel times calculated with the COE models (Clif ton et al. (1984)) is presented which indicates that 1) the results appear to be inconsistent with the theoretical basis of the model and 2) an alternative analysis based on reasonable assumptions for the input parameters would yield estimates of median travel time substantially lower than the 81,000 year estimate which is considered in ene draft EA most representative of tne current state of site nycrologic knowledge.
The spread in the distribution of travel times plotted in Figure 6-22 of the draft EA illustrates the wide range of uncertainty surrounding current travel time estimates.
This uncertainty is due to the scarcity of data on key hydraulic parameters such as effective porosity and vertical hydraulic conductivity, and the questionable reliability and representativeness of existing data on other key hydrologic parameters such as horizontal hydraulic conductivity and hydraulic heads.
Because of this wide range in uncertainty, at present no travel time estimates can be considered to be reliable or representative of true site hydrologic conditions.
This is recognized by the 00E in tne draft EA by noting the nighly preliminary nature of all current ground-water travel time estimates.
However, the NRC staff considers that the preliminary estimate of the median value of ground-water travel time in the draft EA analysis is based on questionable assumptions regarding the key hydraulic parameters noted aoove (horizontal nydraulic conductivity, effective
I l
219 porosity and gradient), and may not be tt 2 mo:t representathe estimate of the present state of knowledge.
The assumptions the CCE uses in reaching the 81,000 year estimate of the travel time are discu sed below.
l Detailed comments 3-22, 6-15, 6-103 and 6-105 indicate that the assumed median l
and distribution of flow top transmissivities as applied to ground water travel time calculationr. are questionable; the draf t EA bases its assumed transmissivity distribution on the assump ion that the mediar. and statistical variation between 011 flow tops is identical to the median,and statistical variation within ea h flow top.
The draft EA does not provide support for this assumption of statis;ical homogeneity between different flows.
There are some indications (Long and WCC,1983) that the medians and distributions within a given flow top may vary significantly between flow tops, as discussed in detailed cements 3-22 and 6-105.
Soecific flow teos with a higher median transmissivity or a lower variance may provide faster, preferred flow paths to the accessible environment.
An expected travel time for each significant flow I
eath must be calculated separately according to the guidelines wnich state tnat the travel time should be calculated along am cath of likely and significant radionuclide travel.
The median (equal to the gecmetric mean, assuming a log-normal distribution) of the ensemble transmissivity distribution u;ad by in tne draft EA analyses is.15 m / day; for the assumed 8-meter thick flow top, r
-2 this translates to a median horizontal hycraulic conductivity of 1.9 x 10 m/ day.
Individual flo,, tops may have median hydraulic conductivities orders of magnitude higher than tnis value (see detailed ccement 3-22).
The draft EA also assumes that the transmissivities have a spatial correlation range of 5 kilometers; there is no data presented in the draf t EA or its supporting documents to support tnis assumption.
In the draf t EA steenastic models, it is assumed snat ef fective porosity has a
~4
-2 uniform distribution within a range from 10 and 10 This type of distribution yields a median value of effective porosity for the model of 5 x 10 The only value measured for a Hanford site basalt flow top is about 2 x
~#
10 for the tested interval (McCoy Canyon flow top) (Leonhart, et al.,1984).
The difference between the median effective porosity assumed in the draft EA and sne single measured value amount: to a f actor of 25; use of tne measured value ratner than the assumed value in the analysis would therefore reduce the travel time estimate by a factor of 25. We also note that the uniform i
distribution assumed for effective porosity is strongly skewed towards the upper limit of the effective porosity range.
In the case of the draft EA analysis, the median value used in the model is a factor of five higher than the geometric mean, which would be the median value of a logarithmic distribution with the same range (e.g., a log uniform distribution).
Since the current uncertainty in tne median value at flow too effective porosity spans many orders of magnitude (Davis, 1984), it appears that the uncertainty distribution is logarttnmically, rather than arithmetically, distributed, and l
that a geometric mean of tha appropriate range should be used as tne median value, rather than the arithmetic mean.
Furthermore, there is some evidence i
that tne seatial variatinn of effecti<e corosity may be logarithnically di stricuted (Loo, et al.,1984).
120 The assumption in the draft EA in the subject travel time analysis regarding the magnitude of hydrologic gradients is also questionable, since in the draft EA attempts are made to estimate the gradients based on head differences between well pairs, rather than along flow paths, as discussed in detailed comment 6-15.
The draft EA assumes a uniform probability distribution of the
~4
~3 hydraulic gradient with a range from 10 to 10
, yielding a median gradient
-4 of about 5.5 x 10 Reasonable estimates of the median hydraulic gradient along ficw paths can be at least twice that value based on some of the existing head data.
The travel times that would be calculated by direct substitution of the assumed median input values for the hydrologic parameters into the ground water travel time equation is about 13.000 years, rather than the 81.000 years yielded by the the draft EA model.
This disparity in the medians is contrary to wnat one would expect analytically, according to the recent work of several authors, as discussed below.
Ground-water velocity is determined by dividing calculated flux with the value of effective porosity for the flow patn.
Calculated flux is directly dependent on the predicted head distribution and the effective hydraulic conductivity along the flow path (as defined in the paper of Smith and Freeze, 1979).
The work of Oettinger and Wilson (1981) indicates that, to first order, estimates of expected hydraulic heads derived from stochastic methods are identical to those that would be credicted by deteministic methods.
Second order effects on the head distribution are generally small (Townley,1984).
The effective hydraulic conductivity of a physically heterogeneous hydrostratigraphic unit with homogeneous statistics (as are assumed in the draf t FA model), even with spatial autocorrelation, has been shown to be given by the geometric mean of a log-normally distributed hydraulic conductivity (Dagan, 1984).
Therefore, it is reasonable to excect that the median value of travel time should be given by the direct substitution of the assumed median values of the head gradient, hydraulic conductivity, and effective porosity in the travel time ecuation.
The fact that this is not the case for any of tne three stoenastic models should be considered in tne final EA.
The effective hydraulic conductivity of the draft EA model, derived from
~4 back-substitution in the travel time equation, is about 3 x 10
, which is almost two orders of magnitude lower than the median and geometric mean (1.9 x 10-2) of the assumed conductivity distribution.
This potential problem is explored in more depth in detailed comment 6-102.
Since the median value can theoretically be approximated with a deterministic calculation, as described in the preceding paragraph, several simple calculations can be performed to illustrate the impact of the 00E's assumed parameter distributions on the resulting median value of travel time.
If the parameter distributions assumed in the draft EA were maintained, as noted above, the NRC staff would calculate a ground-water travel time of about 13,000 years.
If the geometric mean of the ef fective porosity range were used rather than the arithmetic mean, as discussed above, this travel time would be reduced to about 2500 years.
If the single measured value of effective porosity were used rather than the value assumed in tne draf t EA, a travel time of about 600 years would result.
If the measured value of effective porosity, and a more I
i
121 conservative value of the hydraulic gradient magnitude (1 x 10-3) were used, this estimate would be reduced to less than 300 years.
Since the measured effective porosity value may be specific to the interval tested (McCoy Canyon flow too), it may be more representative to limit this calculation to that flow top; in that case, one would obtain a median travel time estimate for this flow top of about 1,500 years (assuming the same hydraulic gradient used in the i
draft EA of 5.5 x 10
, an effective porosity of the flow top of 2 x 10-4 (or an effective thickness of about.002m for the 11m interval) (Leonhart, et al.,
~3 1984), and a 'gecmetric mean hydraulic conductivity of 6.5 x 10 m/ day (or a
-2 transmissWity of 6.5 x 10 m/ day for the same interval) (Long and WCC,1984).
-3 If one assumed the slightly more conservative gradient of i x 10
, a travel time estimate of about 850 years would result.
These estimates indicate that substantially lower estimates of median travel time can ce made based on reasonable, ocn-extreme assumptions that are consistent with the existing data, even within' the limitations of the draft EA conceptual model (horizontal flow for a full, ten kilometers to the accessible environment).
Most of these estimates are less than 10,000 years, and some are less than 1,000 years, which causes the NRC staff to question the DOE's evidence for the findings on favorable condition 960.4-2-1(b)(1) and disqualifying condition 960.4-2-1(d).
The major reasons for the difference between the travel time estimates discussed above and the travel times calculated in the draft EA appear to arise from the difference in effective porosities assumed in the calculations (different, in some cases, by a factor of about 25), and in apparent problems with the two-dimensional numerical modeling used in the draft EA (which result in an apparent overestimation of the travel time by an additional factor of about six; this is discussed in more detail in a following comment).
A report has been prepared a document to support the choice of effective
- thickness values used in the draft EA modeling studies (Loo, et al.,1981).
Tnis document suggests a range of likely values for effective porosity of flow tops based on a combination of Hanford site cata, laboratory core analysis of total and apparent porosity; expert opinion, and available generic literature.
The l
range and dist-ibution, of effective porosity of flow tops suggested by Loo et al. for use in performance assessments are considered torbe'non-conservative (Gordon 1985).
The NRC staff consicers tnat direct.;f ri-situ' testing snould be relied on in evaluating site hydrogeologic parameters such as effective porosity, when such testing is feasible.
The reliability and representativeness of the effective porosity values gained from the two tracer tests performed at the Hanford site is therefore a key question in evaluating the suitability of the site with respect to this disqualifying condition.
It must be emphasized that the above parametric analysis 1s, intended only as.an aid in reviewing the conclusions reached by the 00E through their treatment of the existing hydrogeologic data in the draft EA. The NRC staff does not consider the estimates provided by the above' parametric analysis to offer accurate or reliable predictions of site hydrologic conditions, due to the questionable reliability and representativeness of the underlying data base (see detailed comment 6-15), and cue'to the inherent simplifications of tne calculations presented. The results of this analysis cc, however, raise
122 significant questions regarding the defensibility of the 00E's conclusion that the ground-water travel times can preliminarily be inferred, based on the existing data, to be well in excess of 10,000 years, or that there is a hign probability that the travel times would be greater than 1,000 years.
It is suggested that the final EA provide further explanation of the difference between the median travel time value that would be derived analytically and the media 1 that is yielded by Clifton's modeling studies. Also, it is suggested that the final EA reexamine and provide further support for their choice of medians and distributions of the input parameters, especially effective porosity.
6-102 Section 6.4.2.3.5, Site subsystem cerformance, oages 6-261 through 6-269 Several problems apoear to affect the stochastic analysis of travel times as presented in the draft EA. These problems may be classified as:
- 1) reference availability problems, 2) theoretical problems associated with the development and operation of the models, 3) data input problems associated with the applicability of the transmissivity, effective thickness, and hydraulic gradient values used in the models and 4) presentation problems associated with understanding the significance and limitations on the travel time values presented in the draft EA. All of these problems contribute to the NRC staff having reasonable doubt with respect to the accuracy and applicability of the I
travel time estimates for evaluation of the Hanford site suitability.
The stochastic travel time models presented in the draft EA are based on the work of Clifton, et al. (1983), Clifton (1984), Clifton, et al. (1984a), and Clifton, et al. (1984b). Additional important references include Loo, et al.
(1984) and Arnett, et al. (1984).
Five of the six references were officially released in mid-January,1985. The release of tnese critical reports after the
{
release of the draft EA during the NRC draft EA review made evaluation of the modeling efforts very difficult.
The draft EA alone does not include sufficient detail to allow an evaluation of sensitivity of the travel time estimates to specific input factors and model construction cecisions.
Analysis of theoretical problems with the modeling effort requires presentation of a brief description on the model construction and operation.
The stochastic modeling approach described on pages 6-261 througn 6-268 of the draft EA is based on the operation of a finite element model.
The model includes 10 elements in the directions transverse to flow and 20 elements in the direction parallel to flow. All elements are 1 km square.
The initial step in the modeling is the input of transmissivity values utilizing a multivariate normal random number generator with the of mean log-transmissivity and the unconditional covariance matrix (Clifton,1984, p. 23).
A correlation range for transmissivity of 5 km is assumed to represent the spatial continuity / variability of hydraulic properties within the basalt.
This
123 correlation range is assumed in the absence of sufficient data on each candidate horizon to do a spatial statistical analysis (Clifton, et al.,1983,
- p. 7). The finite element model is then operated under steady-state conditions using the input hydraulic gradient values as boundary conditions to calculate an associated head distribution for the model.
The calculated head distribution then is used to determine a flow path that represents ground water movement from the repository site to the accessible environment, a linear distance of 10 km.
The velocity of ground water movement from element to element along the flow path then is determined using the input transmissivities, the calculated head values and the input effective thickness values. Calculation of the travel time along the flow path involves summing the travel times through each to element along the flow path through the model.
The entire process is tnen repeated witn the generation of a new transmissivity array and tne associated calculation of a nes travel time.
The repetition of this process 600 to 1000 times creates the travel time cata presentec for the three models en page 6-268 of the craft EA.
The travel time array created utilizing the stochastic model apoears to be dependent on both tne characteristics of the model (number of elements, size of 4
elements) and the magnituce and characteristics of the input.
Clifton (1984) did a study of the sensitivity of results to geometry, correlations and cross correlations. His analysis incluced the effect of the size of the model element, the size of the model area, the correlation range of log-transmissivity, and cross-correlations between transmissivity and effective tnickness.
Clif ton's results indicate that the mean travel time reduces from 21,500 years to 16,000 years with an increase in element size from a 1 km square to a 5 km square (Clif ton (1984), p. 45).
Different domain (model are~a) lengths produced little change in travel time wnile doubling the width of the model reduced the travel time by one thi-d (Clif ton (1984), p.
50 and 52).
The magnitude of the correlation range of log-transmissivities in the EA model has a strong impact on median travel times.
The draft EA models are dependent upon a 5 km correlation range. According to Clif ton (1984, p. 56) the median travel time is decreasec oy more tnan 40 percent witn a recuction in tne correlation range from 5 to 2 km.
An increase in correlation range from 5 to 10 km results in an increase in travel time calculated by the 00E stochastic model of about 40 percent. As discussed in detailed comment 6-101, it is not clear to the NRC staff why tne two-dimensicnal model snoulc be tnis sensitive to tne correlation length.
It is suspected that the sensitivity is an artifact of the chosen numerical model geometry, i.e., the domain size and node spacing, relative to the correlation length.
Clifton's results suggest that calculated travel times from the draft EA models are-sensitive to a number of model construction decisions.
Changes in travel time estimates of up to 40 percent, due to grid design and correlation range, are possible without changing the physical (hydrologic) input parameter distributions.
Clifton (1984, p. 30 & 31) also presents example outputs of head configurations based upon model operation.
Figure 12 on cage 31 (reproduced as Figure 6-2) illustrates a potential problem with the travel time models in the draft EA.
The head values show that the model has created a localized zone of low
O 124 transmissivity at right ' angles to the direction of flow.
This " damming" effect acts to retard ground water flow and extend travel times.
It is unknown whether this plot is representative of model outputs.
It is possible that the low transmissivity zone (evidenced by the steep gradient) is created by a combination of the size of the elements, size of the modeled area and size of the correlation range. The NRC staff also notes, regarding this particular figure, that the presence of the closed head contours within the model boundaries appears erroneous, since this would require a source or sink within the model.
1 I
9 4
O a
9 125 to w
y - - -
\\
b
~
us Q
i 0
2 4
8 3
10 1:
14 15 18 20 2
L400RClMATT 410,,,
Figure 6-2.
Hydraulic Head Field Realization, Reference Case Analysis (Clifton,1984).
e 126 1
Arnett, et al. (1984) demonstrate the sensitivity of travel time calculations to seemingly minor changes in input data.
They show how a change in effective
-2 thickness from 4 x 10 m (Loo, et al. (1954), Clifton, et al. (1934)) to 2 x 10-3 (measured in the McCoy Canyon flow top in DC 7/8) can reduce the travel time from 71,000 years to 3,000 years (Arnett, et al., 1984, pp. 23-24). The sensitivity of travel time modeling to changes in input factors is further illustrated in detailed comment 6-102.
6-103 Section 6.4.2.3.5, Site subsystem cerformance, cace 6-261 to 6-269 In stochastic studies of ground water travel time (Clif ton, et al. (1954))
cited in the draf t EA, the flow path from tne disturbed :ene to the accessible environment is considered to occur horizontally within the flow top above the repository hori:en.
Clifton et al. (198a) cerformed a sensitivity study to
_ determine the effect of the vertical to hori: ental hydraulic conductivity anisotropy ratio on ground-water travel time.
They concluded that vertical flow segments along the flow path to the accessible environment would increase the travel time, compared to the hori: ental flow assumotion, and therefore that the horizontal flow assumotion is the most conservative.
The NRC staff considers this conclusion to be questionable for several reasons.
First, Clifton, et al. (1984) assumed each flow top to have the same transmissivity distribution.
If certain flow tops above the candidate horizon are of particularly high transmissivity, vertical flow can result in decreased ground-water travel time.
Second, Clifton et al. (1984) assumed the accessible environment to be ten kilometers laterally distant regardless of the distance of vertical travel.
However, the distance to the accessible environment, as defined in Working Oraf t 4 of the EPA HLW standard, would drop from ten kilometers in tne ceeper aquifers (celow 2500 feet depth) to two kilometers in the upper aquifers (above 2500 feet depth).
Therefore, the travel time to the accessible environment in the upper aquifers would be less than that calculated by Clifton, et al. (1984).
The distance to the accessible environment woula also be less tnan ten kilometers if local grounc water flow to the land surface were found to occur.
Third, neither the vertical gradients nor the hydraulic conductivities (especially vertical hydraulic conductivities) are known with sufficient certainty to conclusively support the draft EA's conclusions.
- Finally, structures and other discontinuities may provide preferential vertical conduits which have not been taken into ac: cunt.
Sased on the above items, the NRC staff considers that the assumption of horizontal ground-water flow may yield grounc-water travel times that are unrealistically long.
s 127 6-104 EA Section 6.4.2.3.5, Site subsystem cerformance, cace 6-261, caragraoh 2 The EA refers to the dependence of ground-water travel time calculations on transmissivity, effective thickness (or effective porosity), and hydraulic gradient.
The NRC staff has questioned the lack of consistency in the use of the term effective thickness in other comments in this review of the draft EA.
The definition of effective thickness used in the 00E (1982) was that portion of the test interval which was deemed to be the portion of the interval contributing flow.
In this section effective porosity is incorporated into this definition. A standard definition in the final EA would be helpful to readers.
6-105 Section 6.4.2.3.5. Site subsystem cerformance, cace 6-266, caracraoh 1 l
The NRC staff has identified several apparent inconsistencies regarding the nature and use of the transmissivity (T) data base in the draft EA.
Statistics for a governing legnormal probability distribution for T are presented, based on Strait and Mercer (1984).
The draft EA then states that it was assumed that distributions governing T within each candidate horizon flow top are the same as the distribution of the ensemble of T values from all Grande Ronde flow tops tested to date.
This assumption implies that the T statistics (geometric mean 2
= 0.15 m / day and standard deviation of log T = 1.83) shown on page 6-266 are based on data from most or all of the tested Grande Ronde flow tops. On page 7-10 of the craft EA it is further implied tnat more tnan 50 i values were I
incorporated within the analysis (see detailed comment 7-1).
l The NRC staff observes that Strait and Mercer (1984) contains T estimates for 42 depth intervals, and of these only 14 relate to basalt flow tops and flow bottoms. The remainder are estimates for intraflow and interbed intervals.
In fact, only 8 estimates of T relate specifically to flow top intervals. Of the group of 14 flow top and flow bottom T estimates, only 3 T values were recorted to have Deen verified by internal and/or external peer review.
Strait and Mercer (1984) recommend that the use of data not verified by peer review should be limited to conceptual modeling. Therefore, it seems inconsistent to ignore the advice of the quoted authors in utilizing preliminary data in the quantitative travel time analyses presented in Section 6.4.2.3.5 of the draft EA.
Based on the fact that only 8 T estimates in Strait and Mercer (1984) relate to ficw tops, a question remains regarding the origin of the quoted T statistics.
We consider it likely that other sources may have been used.
Stone, et al.
(1984) contains 23 estimates of T obtained from the following units: Rocky Coulee flow top, Cohassett flow top and flow bottom, and the Umtanum flow top.
Although this reference cites Strait and Mercer (1984) as its data source, less
4 O
128 than half of the data in Stone, et al.(1984) are contained within Strait and Mercer (1984). With regard to obtaining a governing legnormal distribution for T it would have been logical to utilize data from Stone, et al. (1934).
According to the authors, Table 1 of this reference contains "best" estimates of T based on the professional opinions of hydrologi,ts who conducted the field tests.
It also contains 9 more estimates of T for flow tops and bottoms than are found in Strait and Mercer (1984).
The NRC staff has recalculated the statistics for an assumed governing log-normal distribution af T, based on all data presented in Table 1 of Stone j
et al.(1984). T data from the Cohassett flow bottom were included because in i
the NRC's staff view, the basalt flow bottoms, insofar as they can be differentiated from underlying flow tops, equally represent viable flow and transport paths and they should be treated in the same manner as flow tops.
The results are presented below:
2 T geometric mean = 0.27 m / day Standard deviation of log T = 1.44 The use of these statistical parameters to define the governing distribution for T would have decreased the median travel times in all of the draf t EA's stochastic analyses of Section 6.4.2.3.
In this regard it is also useful to calculate, assuming a log-normal distribution of T, the confidence interval for the geometric mean (median) of T.
Based on the properties of the Student-t distribution, the limits of the 95% confidence interval for the median value of T are 6.3 x 10 3 / day and 1.1 x 100,2 / day.
In other words, it may
-2 2
reasonably be implied that the median ensemble T value, based on 23 samples, is known only within an uncertainty range that exceeds 1 order of magnitude.
This uncert'ainty translates directly to calculatec median ground-water travel times based'on the T data. Of course, uncertainty in the calculated travel times is also derived from the other variables of effective thickness and hydraulic gradient.
The NRC staff recommends caution regarding the assumption that the distribution of the ensemble of flow top T values is the same as the distributions governing T within each candidate horizon flow too.
This assumotion would minimize the impact on salculated grounc-water travel times of a more hignly transmissive Grande Ronde flow top, and is thus non-conservative.
St.itistical tests used to evaluate differences among sample means and differences among variances, based on data from Stone, et al. (1984), fail to reject (alpha = 54) the hypothesis that parameters governing the flow top T dist.ributions are the same as those of the ensemble T distribution.
From this it can only be stated that there is no evidence to conclude that significant differences exist among the means and among the variances.
However, based on this, an assumption that these parameters are essentially the same will entail an unknown risk of Type II (Beta) error.
It should be pointed out that when sample sizes are small, as in this case, differences among means and among variances must be very significant in order to reliably reject a null hypothesis of no difference. Also, the hyoothesis testing orocedure is based on the croperties of a normal
129 distribution and will be inappropriate if the log-transformed T values are not normally distributed.
The NRC staff suggests that the final EA shoul'd reexamine the data base used to derive the T statistics and determine if calculated parameters are truly representative of stated assumptions regarding an ensemble T distribution.
It appears likely that other data sources besides Strait and Mercer (1984) were used to obtain the T statistics.
These sources should be referenced in the final EA.
6-106 Section 6.4.2.3.5. Site subsystem oerformance. Page 6-266, caracraoh 2 The draft EA notes that two of the three factors involved in the estimate of travel times, effective thickness, and regional hydraulic gradient, are either
" difficult to determine accurately" or " uncertain." However, the uncertainty inherent in these two parameters is not in the discussion on page 6-268 and other places in the draft EA where output of the travel time stochastic models I
is presented.
l 6-107 Section 6.4.2.3.4, Recository seals, subsytem cerformance, page 6-273/277 paragraoh 1, 2, and 3/ continuing oaragraph-oullet 1 Radionuclide solubility and sorption values are for "exoected" redox conditions The expected redox condition is considered to -0.30 volts and lower.
The use of these expecte~d condition predetermines that radionuclides will be in a less soluble more sorptive state (see detailed comment 6-28 and 6-33).
Low solubility and high sorption values are apt to lead to low calculations of release.
6-108 Section 6.4.2.4.3, Performance of the site subsystem, page 6-278, paragraoh 2 This analysis was performed using " expected conditons" (i.e. redox = -0.30 volts).
It is premature to take credit for such low redox values (i.e. low solubility /high sorption). According to Early, et al. (1982) and other data concerning redox conditions in the Grande Ronde range from +0.35 volts to -0.4 volts. Many radionuclides are orders of magnitude less soluable as reduced I
specie", than they are as oxidized species.
For example, Early, et al. (1982) calculated that uranium solubility at -0.40 volts has a concentration of 1.0E-10 mol/1, while at -0.0 volts it is around a concentration of 1.0E-5 mol/l
130
~
(and becoming more solub,le as redox conditions become more oxidizing).
The use of redox conditions which predetermine that radionuclides will have low solubilities are act to lead to low calculations of relea se.
6-109 Section 6.4.2.5, eage 6-279. Human intrusion and disructive events,page 6-281, l
Table 6-34, Early Failure Probability and Consecuences Early Failure Probability and Consecuences:
Table 6-34 lists the disruption scenarios that have been identified for further study.
The consequences of some of these scenarios could contribute to waste package failures.
- However, they have not been included in the assessment of canister life (Section 6.4.2.3.3 and Figure 6-16 p. 6-2ta).
The occurrence of items 13, 15, 16 and 17 could generate potential shearing of canisters from tectonic offset of joints and fractures.
Item 38 relates to " premature failure or omission of waste package engineered system." Presumably, this could include waste package early I
failures resulting from flaws in the waste packages as manufactured.
Another scenario with possible adverse consequences in post-closure faulting as discussed in detailed comments 6-42 and 6-43, geologic evidence suggests the existence of a major fault zone, the Rattlesnake Wallula Alignment (RAW),
adjacent to the southwest corner of the present repository location.
The evidence further suggests that the zone is active and capable of a potentially large earthquake, which could involve substantial steeply-dipping fault offsets of the bedrock, including the repository horizon. According to page 2-41 of the draft EA, most of the serious effects from fault rupture occur within 8 km of the fault, which in this case would encomcass about two-thirds of the present repository location.
It would seem that such fault rupture could generate discrete offsets of pre-existing fractures, or faults within the reference repository location.
The consequences of a low probability early failure from any cause would be substantially greater than a " normal" failure.
Therefore, early failure is an important consideration in waste package performance.
l l
The final EA snould consider the potential impact of premature credible failures:
possible major faulting near the repository and the presence of undetected flaws in manufactured packages.
6-110 Section 6.4.2.6.2, Radionuclide release rate, page 285, caragraoh 2 Preliminary performance results, which suggest that basalt has the capacity to isolate radionuclides are based on insufficient data and non-conservative assumptions.
For example, based on inclusive theoretical calculations of redox
131 conditions and, in the absence of data on the reducing capacity of the basalt / water system, it is assumed that radionuclides are released in their l
least soluble, most sorptive state (detailed comment 6-33).
Performance I
assessments based on such assumptions are likely to lead to underestimates of l
radionuclide releases to the accessible environment.
Thus, where data are insufficient for a conclusive evaluation of geochemical conditions and processes, a generally conservative approach to performance assessments should be taken and justified.
6-111 This comment was incorporated elsewhere in the comment package.
1 l
9 t
132
'~
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4 147 CHAPTER 7 COMMENTS 7-1 Section 7.2.1.1, Geohydrology, Favorable conditions for gechydrology, eage 7-5, last paragraon: and cage 7-10, continuing paragrapn It is stated that ground-water traval time calculations for the Hanford site are based on probability distributions for more than 50 known site-specific
)
l values of transmissivity.
The paragraph then restates the ground water travel j
times to the accessible' environment which were calculated in Secticn 6.4.2.3.5.
A reader of the draft EA could get the impression that these travel times are
{
based on more than 50 transmissivity values.
(Note, the travel times were calculated for basalt flow tops.)
The principal reference Strait and Mercer (1984), discusses the transmissivity data base and is cited in the firs; paragraph of page 6-266.
This reference contains 42 transmissivity range estimates. Of these, only 14 represent basalt flow tops or flow bottoms. Of the 14, only 3 data values were reported to have been verified by internal and/or external peer review (Strait and Mercer, 1984,
.page S).
The stated number of 50 transmissivity values should be reconsidered so that the reader may know the actual number of values used in the travel tima calculations. Also refer to detailed comment 6-105 which contains a preliminary review of the draft EA cited reference on the transmissivity data base.
7-2 i
Section 7.2.1.1, Geohydrology, eage 7-10, caragraph 1 The travel times noted in the draf t EA are tNe results of stochastic modeling discussed in Chapter 6.
As noted in preceding detailec comments 6-11, 6-12, 6-15, 6-24, 6-101, 6-102, 6-103, and 6-105 there is reasonable doubt concerning the accuracy and applicability of the travel times presented in the draft EA.
l
o o
0 148
~
Chapter 7 Reference Strait, S., and R. Mercer, " Hydraulic Properties of Selected Zones from Boreholes on the Hanford Site," S0-BWI-OP-051, Rev. O, Rockwell Hanford Operations, 1984.
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June 28, 1985 j
The Honorable Nunzio J.
Palladino Chairman Nuclear Regulatory Commission 1717 H Street, NW.
Washington, D.C.
20555
Dear Mr. Chairman:
Enclosed are a number of letters from the United States Geological Survey (USGS) and a report based on research by USGS geologist Dr. Donald E. White and published by the Health and Energy Institute, education and research organization located in Washington, D.C.
The report, entitled Heata High Water 2 add Rosh Instability at HADf9Id2 is a preliminary assessment of the suitability of the -
Hanford nuclear reservation for a high level nuclear waste repository.
The report, along the with the letters from USGS, raise a number of questions about the site which we believe must be addressed.
We request that the Nuclear Regulatory Commission review the USGS letters and this report, and provide the Subcommittee with an assessment of the issues raised by these documents.
Specifically, your review should address but not be limited to the following questions:
1.
The report raises the possibility that all major repository performance standards required by the Nuclear Regulatory Commission for long-term containment of high level nuclear waste may not be met for the Hanford site.
Please identify any Hanford site characteristics which currently do not, or potentially may not, meet NBC performance standards for a repository.
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2.
The U.S. Geologic Survey has pointed out that a number of exploratory activities in and around the Hanford site, particularly beyond the 10 kilometer radius covering the Pasco Basin, should be completed prior to the shaft construction planned for site characterization.
The USGS also noted that construction of a shaft prior to the completion of these activities would prevent a sound geohydrologic picture from emerging.
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The Honorcblo Nunzio J. Palladino Juna 28, 1985 Pega 2 Does the NRC agree that measurements are needed beyond the 10 kilometer radius in the Pasco Basin?
Does the NRC agree that shaft construction prior to completion may interfere with an adequate set of measurements being taken?
If not, please give detailed reasons.
If yes,
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should shaft construction at Hanford be postponed until these l
measurements are complete?
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3.
Compliance with the spirit and intent of the Mine Health and i
Safety Act and associated regulations is required by the NRC standards specified in 10 CFR 60.
Yet neither DOE's Site Characterization Report, nor NRC's Draft Analysis of that f
Report, nor DOE's Environmental Assessment appear to deal in a detailed and substantive way with the requirements of the Act.
Additionally, the question of possible conflicts between altering mine safety objections and achieving long-term containment is not addressed.
The Health and Energy Institute Report raises both the safety concerns and the possible conflicts, particularly those arising from rockbursting and resulting hydrologic phenomena.
Please comment on whether you agree with the concerns raised in the report.
4.
The horizontal to vertical stress ratio is critical to the
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issue of rock bursting, and all of the stress ratio measurements taken by DOE were greater than 2.0.
It appears that DOE used a design stress ratio of 2.0 for the site, despite the fact that their measurements averaged 2.33 (with l
a high of 2.7) which is only 25 percent below the DOE disqualification mark of 3.0.
The evidence from the core samples indicates that intense core discing is frequent when the stress ratio is greater than 2.0, and that this core discing is probably a forewarning of rock bursting.
A.
Is the stress ratio of 3.0 an appropriate disqualifying level, or should a site be disqualified at some lower level?
B.
Should a site like Hanford, which demonstrates core discing problems be disqualified?
Explain?
In addition, following your review we would like to schedule a meeting between the author of your review and Subcommittee staff to discuss the agency's assessment of the report.
Please contact Nancy Smith at 226-2424 to arrange a mutually convenient time.
The Honorcblo Nunzio J. Palladino Juno 28, 1985 Pr.g3 3 Finally, we would appreciate a written assessment of the report and answers to the questions we have posed by July 12, 1985.
Your assistance in the Subcommittee's on-going review of these documents and the implementation of the Nuclear Waste Policy Act is greatly appreciated.
Sincerely, b
/f h w.1 )7 ')* Ay EDWARD'J. MARKEY DEN Chairman Member Subcommittee on Subcommittee on Energy Conservation Energy Conservation and Power and Power Enclosures EJM:mw d
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