### Department of 

### Energy Carlsbad Field Office P. O. Box 3090 Carlsbad, New Mexico 88221 

## JAN 122010 Ms. Elizabeth Cotsworth, Director Office of Radiation and Indoor Air U. S. Environmental Protection Agency Washington D.C., 20460 Subject: Response to the Environmental Protection Agency July 16, 2009 and October 19, 2009 Letters on the 2009 Compliance Recertification Application Dear Ms. Cotsworth: In response to the Environmental Protection Agency's (EPA) letters of July 16, 2009, and October 19, 2009, the U.S. Department of Energy (DOE) is providing information that answers some the questions included in the enclosures to those letters. DOE determined after review of EPA's letters that the response to many ofthe items noted in the October 19, 2009 letter required additional analysis or significant effort. In order to allow time for those additional analyses, while at the same time responding to the EPA's requests in a timely manner, DOE is providing responses to some of these issues and questions in this submittal. This submittal includes four enclosures. Enclosure 1 is a hard copy ofthe responses. Enclosure 2 (on compact disc) provides references that were not previously submitted with the CRA-2009. Enclosure 3 is a cumulative list of errata that have been identified and corrected up this point. An updated list will be submitted to EPA with future submittals. Enclosure 4 is a table with a summary of comments received, DOE responses in this submittal, responses previously submitted and responses still pending. If you have any questions, please contact Russ Patterson at 575-234-7457. Sincerely,

David C. Moody Manager Enclosure(s) • Responses '. CDs 

## JAN 111010

• Errata 

### 1000071 • Tracking Summary Table 

# MAllROOM COpy

CBFO:ORC:RP:GS:10-0900:UFC 5486.00

### Ms. E. 

### Cotsworth -2­ 

### cc: V. Daub, CBFO 

### * ED R. 

### Nelson, CBFO ED G. Basabilvazo, CBFO ED R. 

### Patterson, CBFO ED S. McCauslin, CBFO ED T. Peake, EPA ED C. Byrum, EPA ED R. 

### Lee, EPA ED S. Kouba, WRES ED A. Chavez, WRES ED T. Klein,WRES ED C. Timm, PMS ED D. Kessel, SNL ED D. Reed, LANL ED B. Crawford, LANL ED CBFO M&RC *ED denotes electronic distribution 

## JAN 1 2 2010

CBFO:ORC:RP:GS:1().()9OO:UFC 5486.004th Response Submittal to the EPA Enclosure 1


### EPA Comment 2-33-2 

### 40 CFR 194.33(c)(2) states: (c) Performance assessments shalldocument that in analyzing the consequences of drilling events, the Departmentassumedthat
... (2) Naturalprocesses willdegrade or otherwise affect the capability of boreholes to transmit fluids over the regulatory timeframe. Brine extraction wells in the vicinity ofWIPP have experiencedsignificant failures andcollapse of formations near surface due to creation of cavernousfeatures at depth. Recently, the Energy andMinerals DepartmentSecretary Joanna Prukop directed the Oil Conservation Division toevaluate current rules and regulations governing brine wells, including an internal auditandwell inspections. While brine wells are consideredin the CRA-2009, it is unclear whether additional analysis wasperformedto determine whether any unforeseen elements that contributed to recent issues may impact CRA assumptions, andwhether these shouldbefurther consideredaspartof the CRA-2009. That is, it is unclear whether these recent phenomenon have been considered, andhow, or 

### if, these mayaffect the transmissivity of formations above the solution collapse. Further, the root cause of thesefailures should· be assessedwith respect to well completionpractices to determine 

### if factors other than brine extraction (i. e. downward flow of fresh water within apoorlycementedannulus) mayhave impacteddissolution. Relatedto this, it is unclear whether the CRA-2009 has assessed injection well integrity for those wells within the 9-township boundary, as no references for this analysis were includedin the CRA-2009. 

### DOE 

### Response The recent regional brine well collapses occurred after much ofthe CRA-2009 was prepared and therefore were not discussed or analyzed in the CRA-2009 documentation. The DOE has been evaluatingthese issues and presents related infonnationinthis response. In summary, the DOE believes thatthese events do not change conclusions or positions presented inprevious compliance applicatIons, although current infonnation will be updated to acknowledge these collapse events and discuss theirrelevance to WIPP screening arguments and decisions. The following presents a more in-depth discussion ofthe brine well collapses, the likelihood ofsimilar events occurring nearthe WIPP, andthe status ofbrine and injectionwells nearthe WIPP. Forregulatory purposes, WIPP assessments ofcompliance mustmake clear distinctions regarding the regional extent ofthe area surrounding WIPP. Historically, the greater Delawarebasin has been used for the calculation ofdrilling rate, and the nine-township area surrounding the WIPP has been deemed appropriate for identifying other likely or relevant activities, particularly those thatrelate to human activities such as drilling and the exploitation ofresources. These distinctions are relevant because mostresource1 January 11,2010

### 4th 

### Response Submittal to the EPA Enclosure 1
related activities are highly dependent upon geology and site-specific characteristics and also becausethese geologic characteristics may change dramatically in a relatively short distance. Forexample, the Capitanreef, which identifies the Delaware Basin'snorthern boundary, is only 7 miles from the WIPP, yet subsurface geology beyond 

### it is quite different thanthat near the WIPP. WIPP personnel have beenfollowing the investigations undertakenbythe NewMexico Oil Conservation Division (OCD) with great interest. In

### its investigation, the OCD has identified probable common causal factors for the recent collapses. These factors include: 1) 

### operation ofbrine wells in shallow salt zones, 2) placement ofthe casing shoe nearthe top ofthe salt zone, 3) use of"reverse" circulation!, and 4) overproduction of brine, thereby creating a large cavern (OCD 2009). These failures have notbeen attributed to well completion techniques or hardware failures (packer, casing, cement, and/or tubular components). The OCD has identified otherbrine wells that may be at risk due to the existence ofthese common factors, and is taking precautionary measures at one well near Carlsbad in which failure may occur. Currently, the nearestbrine solution well is approximately 20 miles from the WIPP (see Figure 2-33-2.1), and its operatiopposes no riskto the operation ofthe WIPP. Within the WIPP vicinity (nine-township area surrounding WIPP); there have been no brine wells developed or operated (past orcurrent). As such, the WIPP is not affected in any way by currently operating brine wells. Withrespect to brine wells that may be established in the future, the DOE has studied the potential effects ofsolution mining as documented in the Third SetofResponses to EPA's March 19, 1997 request for additional information dated 14 May, 1997 (EPA Docket 11-1-31), where it concludedthat the effects ofsolution mining for brine would not affect WIPP performance. Intheir Compliance Application Review Document (CARD) for Section 194.32.B.l, EPA (1998) concurred withthe DOE where it stated that, "
...Basedupon DOE's supplemental information, the restricted scale ofbrine extraction, and the distance involved, EPA concluded that while brine extraction (solution mining) occurs, its effects were appropriately screened out from consideration inthe PA (due to low consequence)." The screening decision of"lowconsequence" continues for the CRA-2009. Appendix SCR-2009, FEP H59, "SolutionMining for Other Resources" discusses the potential effects ofbrine wells onthe WIPP and concludes thatthese wells are screened out ofperformance assessment calculations onthe basis oflowconsequence to the disposal system. Additional·to the conclusion oflow consequence, there are two regulatoryjustifications thatpreclude consideration ofsolutionmining atthe WIPP. First, because brine wells

I Reverse circulation is an injection method which injects fresh water downthe casing/tubing annulus and removes saturated brine viathe tubing. Because the fresh water contacts the salt at the top ofthe cavity, the solution cavity grows in an inverted cone shape, reducing the structural integrity ofthe roof. 2 January 11,2010

### 4tit 

### Response Submittalto the EPA Enclosure 1
have not been developed near the WIPP site inthe past or currenttime frames, the Future States Assumptionprovided in Section 194.25 would exclude such activities in performance assessment. Second, the EPA's own criteriaplace limits onthe nature and scope offuture human activities that relate to drilling. As stated bythe EPA (1998) in their CARD for 194.32.B.l, "
...The Agency fmds that the impact ofsolution mining on the PA does notneed to be analyzed for boreholes drilled inthe future as specified in Section 194.33(d).,,2 As a matter ofpractice, the WIPP projecthas screened speculative future processes such as this onlow consequence, when a low consequence argument can be made. The low consequence arguments used in screening this FEP augments the regulatory exclusions that couldbe applied. With regard to the consequences to formations above a solution collapse, the DOE believes that any effects causedbybrine extraction at or near the WIPP are considered to berepresented bythe mining scenario inperformance assessment. Intheir Supplementary Informationto 40 CFR 194, EPA requires thatperformance assessments incorporate miningby significantly varying the hydraulic transmissivity withinthe overlying rock units (EPA 1996). This is because the most significant effect oftotal removal ofan ore body is understood to be subsidence and disruption ofthe overlying rocks. The effects ofsubsidence due to brine extraction are therefore accounted for within the mining scenario in performance assessment. With respect to evaluating the integrity ofinjection wells within the vicinity ofthe WIPP, no such information was presented inthe CRA-2009. The DOE has since gathered data on well configurations for the 55 wells currently permitted as injection wells within the nine-township area surroundingthe.WIPP (WRES 2009). WRES (2009) shows that all 55 ofthese injection wells are cased throughthe salt sectiontopreclude dissolution ofthe salt should tubing and/or packer failure occur. Additionally, 53 ofthese have at least one

.other casing and/or cementbarrier to further isolate the salt from any potential tubing or packer leak. A representation ofthe wellbore configuration typical ofmost ofthese saltwater disposal wells is presented inFigure 2-33-2.2. It

### should also berecognized that salt water disposal wells such as these differ from brine solution wells inthat the injected fluid is already near saturation and therefore would dissolve the saltvery slowly should the necessary wellbore failures occur such that pressurizedfluid were to be in communicationwiththe Salado formation. Therefore collapse events such as those that have recently occurred inbrine solution wells are not expectedto occur inthe salt water disposal or injection wells inthe vicinity bfWIPP. In summary, the recent brine well collapses are not sufficiently nearthe WIPP to impact repository performance. Additionally, withinthe WIPP vicinity (nine-township area 240 CFR 194.33 Cd) states: "With respect to future drilling events, performance assessments need not analyze the effects oftechniques used for resource recovery subsequent to the drilling ofthe borehole." 3 January 11,2010

### 4th 

### Response Submittal to the EPA Enclosure 1 surrounding WIPP), there have been no brine wells developed or operated (past or current). The DOEbelieves thatthese events do not change current screening arguments ordecisions, that currentperformance assessment models appropriately address uncertain future human-initiated events, and thatcurrentpositions are consistent with regulatory guidance and criteria.3 

### The DOEbelieves thatitis importantto monitor, analyze, and documentthe impacts ofdeveloping issues such as these recentbrine well collapses, and will update compliance documentation as appropriate at each recertification cycle.

3 The Future States Assumption of40 CFR 194.25(a) states that the DOE shall, "
...assume that characteristics ofthe future remain whatthey are atthe time the compliance application is prepared provided that such characteristics are notrelated to hydrogeologic, geologic orclimatic conditions." Therefore, because drilling for resources and conventional potash mining are currently occurring near the WIPP, the DOE assumes these activities will continue in the future and represents them in performance as appropriate. Alternatively, future humanevents such as solution mininghave notbeen included in performance assessment because such activities have not occurred (norpresently occur) in the vicinity near WIPP. 4 January 11,20104th Response Submittal to the EPA Enclosure 1

AC1lYE BRINE WELLS IN 'lEXAS

AND**N~** M!KICO LOCA1!D WIl11IN 11'£ DElAWAIlE IIASIN 

# t '

7 1
7 7 

## , , '.'5' Reeves County



### Figure2-33-2.1 Active BrineWells in Texas and New Mexico Within the Delaware Basin

5 January 11,2010

### 4th 

### Response Submittal to the EPA Enclosure 1

SURFACECASING SIZE (SEE TABLE)

Surface Casing-­ HOLE SIZE (SEE TABLE)

Tubing

Base of Salt _. Intermediate Casing
­ HOLE SIZE 17 1/2" CASING SIZE 13 3/8" HOLE SIZE 12 1/4" CASING SIZE 

### 8 5/8" PACKER HOLE SIZE 7 7/8" CASING SIZE 5 1/2" PERFORATIONS PERFORATION ZONE -{
CIBP and Cement (Cast Iron Bridge Plug) NOT TO SCALE Total 

### Figure 2-33-2.2 

### Typical InjectionWellDesign.

6 January 11,2010

### 4th 

### Response Submittal to theEPA Enclosure 1
DOE References 

### Environmental Protection Agency (EPA) 1996. Title 40 Code ofFederal Regulation Part 194, February 9,1996. Supplemental Infonnation. Federal Register Volume 61, No. 28. pp.5224­ 5245. Washington D.C. Oil Conservation Division (OCD) 2009. Brine Well Collapse Evaluation Report, June 18,2009. NewMexico Energy, Minerals andNatural Resources Department. OCD. SantaFe, NM. Washington Regulatory and Environmental Services (WRES) 2009. Injection Well Design and Operation in the Nine Township Area. October 15,2009. Delaware Basin Drilling Surveillance Program. ERMS 552225. Carlsbad, NM.

7 January 11,2010

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### Response Submittalto the EPA Enclosure 1


### EPA Comment 2-33-3 Dakota Salts, LLC, is a Denver basedcompanythat hasproposedthe use of Deep Salt Caverns for storage of compressedair generatedby windfarms. Dakota Salts currently has eightsalt caverns in North Dakota and, according to their website, is " .
..preparedto enter the regulatory andpermitting stage and is working with the North Dakota Industrial Commission andNorth Dakota Department of MineralResources to establish the State's first regulatory control project" for storage of compressedair thatwouldbe releasedthrough windfarm operations duringperiods of low windgeneration. The CRA-2009, including the DBMR 1
, 

### does not address whether there are any knownplans to use existingsaltorpotash mines for thispurpose. 

### EPA References u.S. Department ofEnergy (DOE). 2007. Delaware Basin Monitoring Annual Report. DOEIWIPP 07-2308. Carlsbad, NM: Carlsbad Field Office



### ·DOE Response Dueto the speculative nature oftrying to predict future human activities, the Future States Assumptionprovided in 40 CFR §194.25 states that performance assessments should, "
...assume thatcharacteristics ofthe future remain whatthey are at the time the compliance application is prepared
... " Since salt caverns are not currently used within the vicinity ofthe WIPP (or the greaterDelaware Basin) for compressed air storage, they have notbeen included in WIPP performance scenarios. Currently, there are no windfarms intheNewMexico portion ofthe Delaware Basin. Consequently, there are no knownplans to use salt caverns for the storage of compressed air generated by windfarms atthis time. Based onthe DOE's wind resource map (see Figure 2-33-3.1) the area in the vicinity ofthe WIPP is listed as "marginal," rendering the development ofwindresources near WIPP inthe future questionable. It

### is acknowledged, however, thatthe economics ofthe future may be suchthat activities that are notprofitabletoday may become more attractive in the future. WIPP monitoringprograms will continue to monitor human activities to keep abreast ofany technological advances used in current resource-related

·activities andto identify the initiation ofnew activities notpreviously employed or attempted in theWIPP vicinity.

· 1DMBR

- Delaware Basin Monitoring Annual Report (DOE 2007) 8 January 11,2010

### 4th 

### Response Submittal to the EPA Enclosure 1


### New Mexico
- Wind Resource at 50 m
108° 106°

34°

32°

108° Wind Power Classification WiBCI ResotJtce Wind F'ovMr Wind Speed" WiBCI Power Potential**Oen$l~** alSO m at60 m at 50 ri1 Class Wlm 2 m/s Il"4lI1 Poor ()
- 200 0.0 - 5.9 0.0· 13,2 Marginal 200 - 300 5,9 - 6.7 13.2 - 15.0 Fait 300 - 400 6.7 - 7.4 15,0 - 16.6 Good 400 - 500 7.4 - 7.9 16.6 - 17.7 Excellenl 500 - 600 7.9 - 8.4 17.7- 18.8 Oulsl:sndlng 600- 800 8.4· 9.3 13.8- 20.8 Superb :> 800 :> 9.3 :> 20,8 ·IIWlnd epeecIseM basad (Il'I aWelbull k or2.0 at 1500 melevation. 104°

Indian Reservation

Navajo UtliMoumln**Jloao'IIIIl~** Taos PicuIIs SlIn Juan !ialltaDal'il Sen lidelgnso POjOIltjue Nsmbe T'*"l
.... Jemez lia Cocl1ttl SatlID Oorniflgo Sen Felipe SantaMa Sarnllso Laguna Acoma 1 CinonclIO

1&IeIa AlIImoNsvajo ZUni Ramah Navajo Mescale<o

;".,,--=,.,.,,===-

__... 200**100~=-,,150** Kllometllrs 30 eo 90 120 Miles Transmission Une" Voltage (kV)

- 115-136 -230

_. 345 -500
• Soun;e:POWERmap,@)Q002

PlatIs, • DMlIon dIMMcGtMo**H1n~1es** 

### u.s. Department ofEnergy National Renewable EnergyLaboratory 12·MA.Y-20031.2.1 

# •
Figure 2-33-301 New Mexico WindResources Map

9 January 11,20104th Response Submittal to the EPA Enclosure 1


### DOE References

.DOE EnergyEfficiency & Renewable Energy Website. 2009. Wind and Hydropower

Technologies Program. Wind Resource Map athttp://www.windpoweringamerica.gov Retrieved November 2, 2009.

10 January 11,2010

### 4th 

### Response Submittal to the EPA Enclosure 1


### EPA Comment 2-33-4 

### Carbon sequestration is beingassessedon a nationwide basis, inCluding the Permian Basin (http://www.southwestcarbonpartnership.org/). The SouthwestRegionalPartnership (SWP), was selectedby the 

# u.s. Department of Energy and its National Energy Technology Laboratory (NETL) as one of the seven regionalpartnerships chargedwith evaluatingavailable technologies to capture andto reduce the emissions intensity of greenhouse gases in the southwest region through aprocess known as carbon sequestration. Theproject includes several different analyses such as CO2coalbedsequestration, saline aquifer CO2sequestration (i.e. injection into saline water-bearingformations), andterrestriallbiotic sequestration. New Mexico was included in the SWP evaluations, as the state contains several highlysaline waterbearing intervals thatmay offer sequestration opportunities. While elements of CO2 sequestration are addressedin difftrentHI[human intrusion]scenarios, C02 sequestration is notspecifically identifiedin the human intrusion analysis. DOE Response It

### is correctthat CO2 

### sequestration is not represented in performance assessment. The following discusses the regulatory and technical bases for the content ofWIPP performance scenarios as theyrelate to future human activities, both inside and outside the WIPP boundary. The WIPP performance assessment includes bothdisturbed and undisturbed performance scenarios. Disturbed performance scenarios include the effects ofinadvertent, intermittenthuman intrusion by exploratory drilling for resources, and include the effects ofa "directhit" ofwaste by the drill bit. This is consistent withthe WIPP Certification Criteria at 40 CFR 194.33 (a)(I), where it states,_ "Inadvertentand intermittent intrusion by drilling for resources ... '" is the most severe humanintrusion scenario." Also, 40 CFR 194.33 (d) limits the scope ofdrilling activities in these scenarios where it states: "Withrespect to future drilling events, performance assessments need not analyze the effects oftechniques used for resource recovery subsequent to the drilling ofthe borehole." Therefore, WIPP Human Intrusion scenarios do notinclude the direct effects ofcarbon dioxide (C02) 

### sequestration (neither saline norterrestrial). However, the effects ofinjection activities outside 

### the WIPP boundary are not excluded from WIPP analyses by the explicitregulatory exemption provided in40CFR 194.33 (d). That is, while they may not be included explicitly in a direct 

### intrusion scenario, such activities may warrant considerationindirectly through analyses ofhuman activities outside the WIPP boundary. Such events are identifiedthrough the WIPP features, events, and processes (FEPs) identification and screeningprocess detailed inAppendix SCR-2009. For example, humaninitiated events thatrelate to injection nearthe WIPP are FEP H27, "LiquidWaste DisposalOutside the WIPP Boundary (OB);" and FEP H28 "EnhancedOil and Gas Production

- OB." Both ofthese activities are currentlypracticed inthe vicinity ofWIPP, and therefore cannotbe
11 January 11,2010

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### Response Submittal to the EPA Enclosure 1
excluded onthe grounds of40 CFR 194.25, "Future States Assumption." As such, thepotential effects ofthese processes were analyzed in Stoelzel and O'Brien(1996) and Stoelzel and Swift (1997) to determine their impact to WIPP performance. These studies analyzed out-of-zone water injection (whether for brine disposal or enhanced oil recovery (EaR)) near the WIPP boundaryto determine ifthe repository would be adversely affected. Because properly functioning injection wells do notresult inthe migration offluids beyond the target interval, failures were assumed to occur inthe tubing packer, the casing, and cement sheath around the casing. Further, it was assumed that injectionpressures above those typically permitted were reached. Even using these worst-case failure modes, the analyses concluded that hypothetical injection failures would not adversely affect WIPP performance. Therefore, FEPs H27 and H28 (liquid waste disposal outside the WIPP boundary and enhanced oil and gas production outside the WIPP boundary) have been excluded from performance assessment calculations due to low consequences to the disposal system. These arguments also hold true ifCO2

### were being injected instead ofwater orbrine
.

.Currently, the WIPP baseline does not include a FEP which specifically addresses CO2 

### sequestration, although aspects ofthis proposed activity are discussed in WIPP FEPs H29, "Hydrocarbon S!orage

- OB," and H59, "Solution Mining for Other Resources." Appendix SCR-2009, Section SCR-5.2.2.4.6, Solution Miningfor Gas Storage states that "
...No gas

### st~~ag~~avities have been solution mined withintheNewMexicoportion ofthe Delaware Basin." No further examination is provided for this activity, due to the Future State Assumption provided at 40 CFR 194.25. Appendix SCR-2009, Section SCR-5.2.2.4.7 Solution Miningfor Disposal states, "
... Solutionmining can be used to create a disposal cavity inbedded salt. Such disposal cavities canbe used for the disposal ofnaturally occurring radioactive material or other wastes. No stich cavities have beenmined oroperated within the vicinity ofthe WIPP." Such disposal would be analogous to a solution cavity beingused for the storage ordisposal of greenhouse gases. However, because no such activity has occurred oris occurring inthe vicinity ofWIPP, no further considerationhas been given (althoughthe effects are not thoughtto be significantly different thanthose represented inthe previous analyses offluid injection). The DOE believes that the periodic recertification ofthe WIPP's performance is an opportunity to take into account advances intechnology and changes and updates to human activities. Such is the case for CO2 

### injection (whether for sequestration orenhanced oil recovery [EORD. Therefore, CO2 

### sequestration is a potential activity that is being monitored inWIPP human activities monitoring. For example, in Appendix SCR-2009, CO2 

### sequestrationis recognized as an activity that could occur inthe future, shouldpolitical and economic forces merit. Ina supporting reference to Appendix SCR-2009, Melzer (2008) evaluates thepotential for CO2 

### sequestrationto be utilized as an EaRtechnique. Melzer illustrates that while CO2 

### flooding is a viable EaRtechnique in certain reservoirs, the potential to use captured carbonfrom industrial processes may make CO2 

### injection evenmore attractive inthe future. While suchtechniques are currentlynot being employed, WIPP monitoring activities will continue to keep abreast ofany 12 January 11,2010

### 4th 

### Response Submittal to the EPA Enclosure 1
advancements and project start-ups that may affect the current state ofhuman industrial practices as they pertainto the WIPP vicinity and WIPP performance. DOE References 

### Melzer, L.S. 2008. An Assessment ofthe C02-Enhanced Oil Recovery Potential inthe Vicinity ofthe Waste Isolation Pilot Plant (June). ERMS 550502. Midland, TX: Melzer Consulting. Stoelzel, D.M., and D.G. O'Brien. 1996. The Effects ofSalt Water Disposal and**Waterfloo~ing** 

### on WIPP. Summary Memorandum ofRecord for NS-7a. ERMS 240837. Albuquerque: Sandia National Laboratories. Stoelzel, D.M., and P.N. Swift. 1997. Supplementary Analyses ofthe Effect ofSalt Water Disposal and Waterflooding onthe WIPP. ERMS 244158. Albuquerque: SandiaNational Laboratories.

13 

### January 11,20104th Response Submittalto the EPA Enclosure 1


### EPAComment 2-33-5 

### In the CRA-2009, DOEchangedthe maximum time a DBR can occur from 

### 11 days to 

### 4.5 days. The maximum DBR duration is represented in PA by theparameterMAXFLOWandusedin the code BRAGFLo. The CRA-2009 states "Kirkes (2007) documents that this change is in keeping with current drillingpractices within the Delaware Basin andtheprevious assumption of 11 days was incorrect. Kirkes and Clayton (2008) document the impacts of reducing the maximum duration of DBR andshow that this change has a very minor impact uponperformance predictions. AppendixPA-2009, Section PA.9.3 discusses the contribution ofDBR to total releases for the CRA-2009performance calculations. Therefore, DOEcontinues to comply with 40 CFR §194.33(c). " Review of Kirkes (above, 2007) raisedthefollowing completeness questions:
a. The South Culebra Bluff Blowout is citedas an inappropriate analogy for a WIPP brine release basedon theformation encountered, downholepressures anticipated, gas content/ignition, etc. The document does not address whether there are analogies elsewhere (e.g. unanticipatedbrinepockets encounteredatrelatively shallow depths in salt formations) thatare more representative of potential conditions anticipatedat the WIPP. EPA References Kirkes, G.R 2007. Evaluation ofthe Duration ofDirect Brine Release in WIPP Performance Assessment (Revision 0). ERMS 545988. Carlsbad, NM: SandiaNational Laboratories. Kirkes, R, and D. Clayton. 2008. Impact Analysis ofDecreased Duration ofDirectBrine Release in WIPP Performance Assessment, Revision 

### O. (March 10). 2008. ERMS 548313. Carlsbad, NM: SandiaNational Laboratories.


### DOE Response While there are limited reported occurrences ofbrine flows from units above the Delaware Mountain Group, there are no cases ofcatastrophic well control loss, as inthe South Culebra

.Bluff. As documented in Kirkes (2007), conversations with drillers indicate that occurrences of pressurizedbrine flows are quite rare inthe vicinity ofWIPP, and whenthey do occur, drilling progress isseldom interrupted. Incases whenthe driller chooses to shut 

### inthe well, 

### itis done due to the presence ofgas orto determinethe presence ofgas. Ifno gas is present, then drilling

14 January 11,2010

### 4th 

### Response Submittalto the EPA Enclosure I

resumes. Gas kicks 1 

### are more difficult (and dangerous) to handle because gas entrained in the mud returns lightens the mud column and may threaten well control. Therefore, the majority of drillers surveyed inthe analysis state that they would shut in a gas kick, but would let a brine kick flow, once the absence ofgas was confirmed (allowing the flow ofbrine does not slow drilling, casing, and cementing procedures as discussed further inresponse to comments 2-33-5c and 2-33-5d). Unmitigated flow from the repository to the surface is represented by the DBR scenarIO. The DOEbelieves thatthe hypothetical scenario posedto the drillers inthe survey (Kirkes 2007) accurately represents downhole conditions representative ofa pressurizedrepository. The survey responses effectively reflect how a driller would react to a pressurizedbrine flow originating from the Salado and represents currentpractice in the area. The drillers' responses to the hypothetical scenario are consistent with what is documented in EPA's Background Information Document (BID) for 40 CFR 194 where the Cedar Breaks "2" State (API 30-015-27406) intercepted a pressurized brine flow in the McNuttpotash zone ofthe Salado Formation May 1, 1993. NewMexico Oil Conservation Division (OCD) records showthat this well was temporarily shut in for four hours, flow rates were determined and the absence ofgas was verified. Drillingthen continueduninterrupted while brine was allowed to flow until the target depth for the intermediate string was reached (1,555 

### ft belowground surface). The casing was then set and cemented without interruption. The driller's reaction to this unexpected water flow is very consistent withthe answers provided bythe drillers interviewedin Kirkes (2007a). While the Cedar Breaks "2"well is outside the Delaware Basin, it does provide a useful analog regarding a driller's reaction to anunexpected pressurized brine flow and is consistent withboth the mostrecent driller's survey and the assumptions used in the currentDBR model. DOE References Kirkes, G.R. 2007. Documentation ofPersonal Interviews with WIPP Area Drilling Personnel. April 26, 2007. ERMS 545980. Carlsbad, NM: SandiaNational Laboratories.

1 A "kick" is an entry ofwater, gas, oil, or other formation fluid into the wellbore during drilling. It occurs because the pressure exertedbythe column ofdrilling fluid is not great enough to overcome the pressure exerted bythe fluids inthe formation drilled. 

### 15 January 11,20104th Response Submittalto the EPA Enclosure 1
EPA Comment 2-33-5 

### b. Review of drillers' comments (Memorandum, DocumentNumber 545844) 

### indicates that many drillers have never encountereda situation thatwouldrequire mitigation of a brine release orblowoutatshallow depths in the Delaware Basin. Kirkes (2007) takes this into account by calculating the anticipatedtime it wouldtake·to acquire appropriate materials, but it is unclear whether the actual response timefrom the crew takes into account this lackof experience. Please indicate whether there are any other considerations short of materialavailability, that were consideredwhen evaluating this circumstance. EPAReferences 545844 (Kirkes, G.R. 2007). Documentation ofPersonal Interviews with WIPP AreaDrilling Personnel. April 26, 2007. ERMS 545844 (Superseded byERMS 545980). Carlsbad, NM: SandiaNational Laboratories. Kirkes, G.R. 2007. Evaluation ofthe Duration ofDirect Brine Release in WIPP Performance Assessment. April 27, 2007. ERMS 545988. Carlsbad, NM. SandiaNational Laboratories. DOE Response Conservative assumptions (such as maximum repository pressures) were used when developing the hypothetical scenario representedto the drillers inthe survey. When evaluating the responses from the drillers, other**consid~rations** such as badweather and conservative travel times were used inthe development ofthe response time. However, while it is correctthat most drillers have notencountered a situation similarto the hypothetical scenario presented in the questionnaire inKirkes (2007a), this should notbe interpreted as a lack ofknowledge of commonwell control techniques. All the drillers interviewed were very familiar withkill techniques 1 and state thatthe primary safety feature onthe drilling rig is the blow-outpreventer (BOP). All drillers interviewed state thatthey have BOPs rigged up and that these BOPs are routinely tested. In addition to BOPs, mud additives suchas weight agents (barite) are either on site orreadily available from local vendors. One driller stated thatthey 

### may notyethave such additives on site while drilling the intermediate section ofthe borehole, because over-pressurized brine orgas is so rare at such a shallow depth. Therefore, inthis case, weight additives wouldbe broughtto the site priorto drilling deeper zones where overpressure is more common. Another drillerin the survey statedthatbarite or other additives are always onhand athis rig.

1"Killtechniques" are methods usedto overcome pressure in a well by use ofmud or heavy drilling fluids such that the hydrostatic pressure within the wellbore (as exertedby the drilling fluid) exceeds formation pressure, thus prohibiting formation fluids orgas from enteringthe wellbore. 

### 16 January 11,2010

### 4th 

### Response Submittal to the EPA Enclosure 1
The mitigation scenario inthe DBRReport (Kirkes 2007b) conservatively assumed thatmud weighting additives would not bepresent on site andtherefore wouldbe trucked in after the high pressure zone was encountered. Inthe case ofa highpressure kick thatthreatens losing control ofthe well, the BOPs would be activated (closed), thus shutting inthe well. During this shut-in period, weight additives couldbe mixed (ifonhand), or dispatched from the nearestvendor if not available on site. 

### DOE References Kirkes, G.R. 2007a. Documentation ofPersonal Interviews withWIPP Area DrillingPersonnel. April 26, 2007. ERMS 545980. Carlsbad, NM: SandiaNational Laboratories. Kirkes, G.R. 2007b. Evaluation ofthe Duration ofDirect Brine Release in WIPP Performance Assessment. April 27, 2007. ERMS 545988. Carlsbad, NM: SandiaNational Laboratories.

17 January 11,20104th Response Submittal to the EPA Enclosure 

### 1
EPA Comment 2-33-5


### c. Several drillers (reference 545844) indicatedthat they may never detect a brine release from the repositorygiven the hypothetical release conditionsposedbyKirkes (2007).

While this may be improbable under the assumeddownholepressure conditions, the consequences that a lack of release detection wouldhave with respect to release scenarios orperformance assessmenthas notbeen addressed in the references reviewed or in Kirkes (2007). Pleaseprovide this information. EPA References 545844 (Kirkes, G.R. 2007). Documentation ofPersonal Interviews with WIPP Area Drilling Personnel. April 26, 2007. ERMS 545855 (Superseded byERMS 545980). Carlsbad, NM: SandiaNational Laboratories. Kirkes, G.R. 2007. Evaluation ofthe Duration ofDirect Brine Release in WIPP Performance Assessment (Revision 0). ERMS 545988. Carlsbad, NM: SandiaNational Laboratories 

### DOE Response There would be no impacts uponthe current DBRmodeling assumptions ifa driller failed to detectthat a brine flow was occurring. Infact, this is precisely whatthe DBRmodel assumes. CurrentDBRconditions are such that a DBRwill occur if: 1) repository pressure exceeds 8 megapascals (MPa), and 

### 2) the repository contains sufficientmobile brine. The DBRmodel then assumes that flow will continue until one ofthe following occurs: 1) repository pressure drops below 

### 8 MPa, 

### 2) available brine is depleted, or 

### 3) the 4.5 day maximumDBRduration is reached. Inthe case where the driller does notnotice that a flow is occurring, the intermediate section ofthe borehole would be'completed, cased and cementedwithinthree days, according to currentpractices inthe vicinity (Leonard, 1996). Because the minimum duration for DBRhas been set at three days, failure to detect is represented by allowing flow while normal drilling, casing, and cementing operations continue (unless one ofthe limiting assumptions above occurs first). Ifrepository conditions merit, flow may continue, although this is a conservative assumption and ignores the fact thatthe driller would complete this section oftheborehole in three days orless. This three-day minimum duration is based onprevious WIPP surveys and information in Section 9.3.1.2 ofEPA's BackgroundInformation Document (BID) for 40 CFR 194 (EPA 1996). 

### DOE References Environmental ProtectionAgency (EPA). 1996. Criteriafor the Certification andReCertification ofthe Waste Isolation Pilot Plant's Compliance with the 40 CFRPart 191 Disposal

18 January 11,2010

### 4th 

### Response Submittal to the EPA Enclosure 1 Regulations. Background Information Document for 40 CFR Part 194. EPA 402-R-96-002. Environmental Protection Agency, Office**of~adiation** 

### and Indoor Air, Washington, DC. Leonard, R.J. 1996. "Commonality ofPressurized Brine Encounters within the Delaware Basin." Memorandum from R. Leonard to M. Marietta. July 31, 1996. ERMS 240850. Carlsbad, NM: Westinghouse Electric Corporation.

19 January 11,2010

### 4th 

### Response Submittal to the EPA Enclosure 1


### EPA Comment 2-33-5 d One driller interviewed in reference 

### 545844 indicatedthat 

## if a brine kickwas encountered, he wouldprobably let brineflow to surface without any attempt at mitigation. However, Kirkes (2007) andother references examineddo notappear to address the likely duration ofunmitigatedflow andimpact on PA assumptions. Please provide or cite references that address this occurrence. 

### EPA References 545844 (Kirkes, G.R. 2007). Documentation ofPersonal Interviews with WIPP Area Drilling Personnel. April 26, 2007. ERMS 545855 (Superseded by ERMS 545980). Carlsbad, NM: SandiaNational Laboratories. Kirkes, G.R. 2007. Evaluation ofthe Duration ofDirect Brine Release in WIPP Performance Assessment (Revision 0). ERMS 545988. Carlsbad, NM: Sandia National Laboratories 

### DOE Response As stated in theresponse to EPA question 2-33-5c, there would beno impacts upon the current DBRmodeling assumptions ifa driller failed to detect that a brine flow was occurring. As identified in Kirkes (2007), not all drillers state thatthey wouldreact inthe same manner to the hypothetical conditions presented in the questionnaire. Reactions vary based onpersonal experience, training, and other personal factors such as risk aversion, etc. It

### is clear, however, that most drilling decisions are based on maximizing drilling efficiency and continued progress towards target depth. Some drillers state that only when a fluid flow is sufficient to exceedpit capacity (thus requiring excess brine to betrucked away for disposal), would shutting in the well become necessary. Otherwise stated, only whenthe flow becomes an obstacle to drilling progress, orpresents a safety or environmental concern, would mitigation techniques be sought. Therefore, under these circumstances, the flow would continue until the intermediate interval was drilled, cased, and cemented. These procedures would take no more thanthree days, which is the minimumduration for direct brine release (Leonard 1996). Therefore, unmitigated flow has no impact onperformance assessment assumptions, and is represented bythe three-day minimum duration used inperformance assessment. 

### DOE References Kirkes, G.R. 2007. Documentation ofPersonal Interviews with WIPP AreaDrilling Personnel. April 26, 2007. ERMS**545980~** 

### Carlsbad, NM: SandiaNational Laboratories.

20 January 11,20104th Response Submittalto the EPA Enclosure 1 Leonard, R.J. 1996. "Commonality ofPressurized Brine Encounters withinthe Delaware Basin." Memorandum from R. Leonard to M. Marietta. July 31, 1996. ERMS 240850. Carlsbad, NM: Westinghouse Electric Corporation.

21 January 11, 20iO

### 4th 

### Response Submittal to the EPA Enclosure 1


### EPA Comment 2-33-5



### e. Additionally, it is unclear what effect brine shut-in wouldhave with respect to duration of flow anddownhole conditions. Pleaseprovide references that address the effects that surface shut in (prior to brine kill) wouldhave on downhole conditions below the surface casing, assuming thatsurface casing is setto approximately 900ftwith the remainder of the hole open. (At thatpoint, intermediate casingwouldnot have been set.) 

### DOE Response Ifpressures were sufficient to cause the well to be shut-in, flow from the**w~llbore** 

### into the casing (andupwards to the surface) would cease. The following excerptfrom Kirkes (2007) provides an explanation offlow and relative downhole pressures:

"
... Should a high pressure kick occur (approaching an SIDPP [Shut-in Drillpipe Pressure] of 1,000 psi), itis standard procedure for the driller to shut-inthe well. Such is the case during the "wait and weight" method ofwell control (Grace, 2003). During this shut-inperiod, no flow to the surface occurs. Only during the actual kill procedure, when the kill-weight mud is being pumped downthe drillpipe, can formation fluids (inthis case contaminatedbrine from the repository) flow to the surface. Duringthe kill procedure, mudreturns are regulatedthrough a choke until kill fluids have been circulated downthe drill string and backup the**drillpipe/c~ing** 

### annulus. Oncethe kill-weight mudhas been circulated completelythroughout the well, there should be zero surface pressure on the drillpipe and the drillpipe/casing annulus, indicating zero flow into the wellbore (Grace, 2003). In such a scenario, fluid from the repository could only flow into the wellbore during the kill procedure, and then only at a very slowrate, due to the choking and regulatingprocess used in the kill procedure. This may result inflow to the surface ofonly one-halfhour or less; the period oftime ittakes to circulate the kill fluid (Grace, 2003). Once the flow has been killed, normal drilling operations would continue until the target depth for the intermediate stringis reached. The kill-weight mud would continue to be usedthroughout the remainder,ofthis interval, thus keeping high pressure formation fluids inplace. Finally, when setting the intermediate casing string,the heavy mud would continueto be used until the casingis set and cemented. It

### is likelythat very little flow from the repository would occur, once thekill-weight mudwas in circulation." The point ofthis observationis that should a driller encounterpressure sufficientto warrant shutting inthe well while a kill-weight mud was prepared, the duration offlow to the surface would be even less 

### (perhaps significantly less) than ifthe flow was undetected, and allowedto 22 January 11,2010

### 4th 

### Response Submittal to the EPA Enclosure 1
continue until the intermediate string interval was cased and cemented. That is, when consideringreal-world drilling techniques (not those used in a hypothetical model), higher pressures do not necessarily result in increased flow or duration. The current DBR model employed in WIPP performance assessment conservatively ignores the fact that a shut-in well does not flow to the surface. DOE References 

### Grace, R. D. 2003. "Blowout and Well Control Handbook." Elsevier Science, 2003. Kirkes, G.R. 2007. Evaluation ofthe Duration ofDirect Brine Release in WIPP Performance Assessment. April 27, 2007. ERMS 545988., Carlsbad, NM: SandiaNational Laboratories.

23 January 11,20104th Response Submittal to the EPA Enclosure 1


### EPA Comment 3-23-9 FEPs (194.23) EPA supports the systematic approach requiredbySP 9-4 andbelieves that itwill improve the maintenance, accuracy, and traceability of DOE's FEPs baseline. In reviewingSP 9-4, EPA founddiscrepancies in the identification of documentation thatshouldbe resolved. Section 3.0 of SP 9-4 identifies three QA Records: a FEPsAssessmentAnalysisReport, a DocumentReview CommentformperNP 6-1, anda RevisedBaseline FEPs List(BFL). The FEPsAssessment AnalysisReportappears to be the report documenting the results andrecommendations of the baseline FEPs assessmentmentionedin Section 2.4.8 of SP 9-4, however, Section 2.4.9 of SP 9-4 states that the PA Manager is to sign the cover sheet for the FEPs ImpactAssessmentReport. 

## If the FEPs ImpactAssessmentReport is different from the FEPsAssessmentAnalysisReport, it shouldalso be includedaspart of the QA record. 

## If these are the same reports, theyshouldbe given the same name. DOEshouldclarify these differentdocuments when including them in the future. DOE Response The EPA is correct in identifyingthe inco11.sistency in nomenclature in sections 2.5.9 and 3.0 of SandiaProcedure (SP) 9-4 (Kirkes 2009). Theterms, "FEPs Impact AssessmentReport" and "FEPs Assessment Analysis Report" are infact referring (in generic terms) to the unique report generated for eachFEP assessment, not a specific FEPs assessmentreport. In SP 9-4, these terms are used generically, since eachFEP assessment is namedwith a specific title indicating the scope ofthe assessment (e.g., "FeaturesEvents andProcesses Assessment for the Panel Closure System Redesign"), howeverthe inconsistency is not appropriate andwill be corrected viarevision ofSP 9-4. DOE References Kirkes, G.R. 2009. Activity/Project Specific Procedure SP 9-4, Performing FEPs Baseline Impact Assessments for Planned orUnplanned Changes, Revision 2. August 24,2009. ERMS 551859.Carlsbad, NM: SandiaNational Laboratories.

24 January 11,2010Enclosure 3 eRA 2009 ErrataTracking

Error# 1 .. Error Description EPA comment 1-C-15 In Appendix SOTERM-2009, Table SOTERM-21, the parameter descriptions for PHUMCIM and PHUMSIM indicate "actinide solubilities are inorganic only (complexes with man-made organic ligands are not important); solubilities were calculated assuming equilibrium with Mg-bearing minerals (brucite and magnesite)." DOE should correct these statements to clarify that organic ligands were considered during calculation ofthe solubilities used with these proportionality constants for the CRA-2004 PASC, and that the solubilities were calculated assuming equilibrium with brucite and hydromagnesite. . . Correction The description for PHUMCIM in Appendix SOTERM-2009, Table SOTERM-21 should be changed to "Proportionality constant for concentration ofactinides associated with mobile humic colloids; in Castile brine; actinide solubilities include organics (complexes with man-made organic ligands); solubilities are calculated assuming equilibrium with Mg-bearing minerals (brucite and hydromagnesite)." . ','

.. :

... Originator EPA ,.. , ':.:';:.:'

..':"" Responsibility LANL-Reed :'., Status Revised text included in 1st Response Submittal to the EPA .. Date of Completion Submitted to EPA in 1st Response Aug 24,2009

2 EPA comment 1-C-15 In Appendix SOTERM-2009, Table SOTERM-21, the parameter descriptions for PHUMCIM and PHUMSIM indicate "actinide solubilities are inorganic only (complexes with man-made organic ligands are not important); solubilities were calculated assuming equilibrium with Mg-bearing minerals (brucite and magnesite)." DOE should correct these statements to clarify that organic ligands were considered during calculation ofthe solubilities used with these proportionality constants for the CRA-2004 PASC, and that the solubilities were calculated assuming equilibrium with brucite and hydromagnesite. The description for PHUMSIM in Appendix SOTERM-2009, Table SOTERM-21 should be changed to "Proportionality constant for concentration ofactinides associated with mobile humic colloids; in Salado brine; actinide solubilities include organics (complexes with man-made organic ligands); solubilities are calculated assuming equilibrium with Mg-bearing minerals (brucite and hydromagnesite)." EPA LANL-Reed Revised text included in 1st Response Submittal to the EPA Submitted to EPA in 1st Response Aug 24, 2009



## .

Page 1 of 11Enclosure 3
3 EPA comment 1-C-18 The following statementshould be added at EPA SNL-Brush Revised text
. Submitted to EPA In Appendix MgO-2009, Section 4.2.2, DOE claims the end of Subsection 4.2.2 ofAppendix included in 1st in 1st Response that hydromagnesite will completely convert to MgO 2009 to clarify the text in this Response Aug 24, 2009 magnesite during the 10,000 year WIPP regulatory subsection: "Based on the evidence Submittal to the time period. However, DOE's evaluation ofthe discussed above, the DOE concludes that it EPA likely conversion of hydromagnesite to magnesite is still unclearwhether hydromagnesite will ignores information about this issue presented in persist or convert to magnesite during the SCA (2008). As part ofa thorough evaluation of 1O,OOO-year WIPP regulatory period. the likely conversion rate for hydromagnesite to However, the EPA has specified that the magnesite, SCA (2008) cited data from Vance et brucite-hydromagnesite (5424) reaction be al. (1992) that showed hydromagnesite can persist used to buffer the C02 fugacity for for as long as 6,200 years. In addition, DOE does compliance-related actinide-solubility not considerthat slow CPR degradation will result calculations since the CCA PAVT (Trovato, in continuous brucite carbonation during the 1997; U.S. EPA, 1998)." 10,000-year regulatory period, rather than hydromagnesite formation that occurs only for a short time following repository closure. Consequently, even if hydromagnesite formed in the repository converts to magnesite within a few thousand years, hydromagnesite is likely to remain in the repository and would be likely to influence carbon dioxide fugacity forthe entire 10,000-year regulatory period. DOE should revise this discussion to show that hydromagnesite is likely to be present in the backfill throughout the WIPP

- regulatory period.

Page 2 of 11Enclosure 3

4 EPA comment 1-C-19 In Appendix MgO-2009, Section 5.1, DOE states that the actinide solubilities in WIPP brines calculated for the CRA-2004 PA and CRA-2004 PABC differed because of "changes in the thermodynamic databases for the An(III), An(IV), and An(V) models." The thermodynamic database for the An(IV) model changed between these two PA calculations when the chemical potential (IJO/RT) forTh(OH)4(aq) was revised. On the other hand, the An(III) and An(V) solubility results changed because ofa recalculation of ligand concentrations. EPA was not informed ofany changes to the thermodynamic data for the An(lll) and An(V) oxidation states. DOE should either correct this statement or document the revised thermodynamic data. The statement that, 'The An(III), An(IV), and An(V) solubilities predicted for the CRA-2004 PA and PABC calculations are different for· both brines because ofchanges in the thermodynamic databases for the An(III), An(IV), and An(V) models between these calculations" (U.S. DOE, 2009, Appendix MgO, Subsection 5.1, p. MgO-32), is incorrect. It should state, "The An(III) solubilities predicted for the CRA-2004 PA and PABC calculations are different for both brines because ofan increase in the concentration of EDTA (compare Brush and Xiong, 2005, Table 4, columns labeled "CRA2004 PA" and "PABC"). The An(IV), solubilities predicted for the CRA-2004 PA and PABC calculations are different for both brines because of changes in the thermodynamic database for An(IV). The An(V) solubilities predicted for the CRA-2004 PA and PABC calculations are different for both brines because ofthe inclusion ofthe solubility-limiting phase whewellite (Ca oxalate·2H20) in the FMT database, which decreased the dissolved oxalate concentration despite an increase in the concentration ofoxalate prior to precipitation ofwhewellite (compare Brush and Xiong, 2005, Table 4, columns labeled "CRA-2004 PA" and "PABC"). EPA SNL-Brush· Revised text included in 1st Response Submittal to the EPA Submitted to EPA in 1st Response Aug 24, 2009

Page 3 of 11Enclosure 3

5 EPA comment 1-C-20 In the discussion of MgO uncertainties (Appendix MgO-2009, Section 6.2.4.4), DOE does not include the uncertainties associated with the chemical composition ofthe cellulose, plastics, and rubber in the WIPP inventory. DOE should acknowledge this uncertainty in the discussion. The following statement should be added at the end ofthe first paragraph of Subsection 6.2.4.4.1 ofAppendix MgO-2009, "Vugrin et al. (2006) did not include uncertainties associated with the chemical compositions of the CPR materials in the WIPP inventory. However, the DOE acknowledges that there are uncertainties associated with the EPA SNL-Brush Revised text included in 1st Response Submittal to the EPA Submitted to EPA in 1st Response Aug 24, 2009

chemical compositions ofthese materials."

6 EPA comment 1-C-21 Appendix PA-2009, Table PA-1O does not include units forthe concentrations, which should be moles/L The units moles/L should be added to Appendix PA-2009, Table PA-1O. EPA SNL-Clayton Revised text included in 1st Response Submittal to the EPA Submitted to EPA in 1st Response Aug 24, 2009

7 EPA comment 1-C-22 Appendix PA-2009, Section 4.9 includes a statement that releases are controlled almost entirely by direct releases to the surface as cuttings, cavings, and slJallings. DOE should correct this statement to include cuttings, cavings, and direct brine release, as explained in Appendix In Appendix PA-2009, Section 4.9, page PA162, line 2, the phrase "cuttings, cavings, and spallings" should be changed to "cuttings, cavings, and direct brine releases". EPA SNL-Claytcin Revised text included in 1st Response Submittal to the EPA Submitted to EPA in 1st Response Aug 24, 2009

PA-2009, Section 9.0.

8 EPA Comment 1-C-10 Chemistry Issues In Appendix SOTERM-2009, Section 4.4, DOE states thatthe chemical potential (!lo/RT) for Th(OH)4(s) was changed in the FMT database since the CRA-2004 PA. However, only the chemical potential for Th(OH)4(aq) changed between the CRA-2004 PA and the CRA-2004 PABC (Xiong et al. 2005). DOE should correct this The DOE agrees with this comment - this is a typographical error in the text. The text will be corrected to read Th(OH)4 (aq). Note that this is correctly stated in Figure SOTERM-17 and Equation SOTERM. 48. EPA LANL-Reed Revised text included in 2nd Response Submittal to the EPA Submitted to EPA in 2nd Response Oct, 2009

statement

-. Page 4 of 11Enclosure 3
9 EPA Comment 1-C-11 In Appendix SOTERM-2009, Section 4.4, DOE should explain what is meant by their statement that, "The effects of hydromagnesite and calcite precipitation were added

..." to the FMT database for the CRA-2004 PABC, because hydromagnesite and calcite thermodynamic data have been included in the database at least since the CCA PAVT. In addition, SOTERM-4.4 states that the version ofthe code used was FMT_050405.CHEMDAT, which is the database version, not the code. DOE should correct this misstatement. The EPA is correct in their statement that hydromagnesite and calcite precipitation were included in the FMT calculations at least since the time ofthe CCA PAVT. The second bullet inSOTERM-2009, Section 4.4 should be replaced with, "The dimensionless standard chemical potential for whewellite (CaC204oH20) was added to the database (Xiong 2004)." The first sentence in SOTERM-2009, Section 4.4 should read, "The version ofthe database used with the FMT code for the CRA-2004 PABC was FMT_050405.CHEMDAT (Xiong 2005)." These corrections will be added to the errata list for Appendix SOTERM-2009. EPA LANL-Reed Revised text included in 2nd Response Submittal to the EPA Submitted to EPA in 2nd Response Oct, 2009

10 EPA Comment 1-C-17 Chemistry Issues
- Proper The DOE agrees with this comment. Brush EPA LANL-Reed Included in 2nd Submitted to EPA ReferenCe for Brush (2005) in Section 2.3.2 2005 is the correct reference. This will be Response in 2nd Response In Appendix SOTERM-2009, Section 2.3.2, Brush added to the errata list for Appendix Submittal to the Oct, 2009 et al. (2006) is cited as part ofthe documentation SOTERM-2009. EPA for the CRA-2004 PABC, but this report was prepared after the CRA-2004 PABC. DOE should replace it with the correct reference (Brush 2005).

Page 5 of 11Enclosure 3

11 EPA Comment 1-23-5 Chemistry IssuesInconsistencies in pH in SOTERM In Appendix SOTERM-2009, Section 3.3.2 and 1) Change the following in Appendix SOTERM Section 3.3.2: "At the expected pCH+ in the WIPP (-8.7), EPA LANL-Reed Included in 3rd Submitted to EPA Response in 3rd Response Submittal to the Nov 2009 SOTERM-2009, Section 3.6.2, DOE states that the the measured uranium solubility was EPA pcH ofthe WIPP brines is expected to be between 10-7 M and 10-6 M." approximately 8.7 or 8.5. Based on FMT modeling To: performed for the CRA-2004 PABC, however, the pcH ofGWB and ERDA-6 are expected to be 9.39 "At the expected pCH+ in the WIPP (-9.5), and 9.64, respectively. The pcH values cited by the measured uranium solubility was DOE seem to reflect the pH values of8.69 and between 10-7 M and 10-6 M." 8.94. DOE should correct the cited pcH values and reinterpret the solubility data in light ofthe correct 2) Change the following in Appendix

. values. SOTERM Section 3.6.2: "The WIPP-relevant data summarized in this report support current PA calculations performed with the use ofthe Pitzer model (U.S. Department of Energy 2004, Appendix PA, Attachment SOTERM) for the values of 3 x 10-7 M and 1.7 x 10-7 M in GWB and ERDA-6, respectively, at pCH+-8.5." To: "The WIPP-relevant data summarized in this report support current PA calculations performed with the use ofthe Pitzer model (U.S. Department of Energy 2004, Appendix PA, Attachment SOTERM) for the values of3 x 10-7 M and 1.7 x 10-7 M in GWB and ERDA-6, respectively, at pCH+-9.5."

Page 6 of 11Enclosure 3
12 IEPA Comment 1-C-8 Chemistry Issues -Issue of lin Section 2.3.2, Page 10, line 12-16 of IEPA LANL-Reed Included in 3rd Isubmitted to EPA pH in microbial and non-microbial vectors Appendix SOTERM change: Response in 3rd Response "Under these repository-relevant conditions, Submittal to the Nov 2009 The fourth paragraph ofAppendix SOTERM-2009, Ithe expected pH, when little or no carbonate EPA Section 2.3.2 states: is present, is 8.69 in GWB brine and 8.94 for ERDA-6 brine. In both cases, this pH is "the expected pH, when little or no carbonate is established/buffered by the brucite present, is 8.69 in GWB brine and 8.94 for ERDA-6 dissolution reaction. The presence of brine. In both cases, this pH is

. microbial activity will potentially contribute established/buffered by the brucite dissolution significant amounts of carbon dioxide and reaction. The presence of microbial activity will leads to a model-predicted pH of 8.69 and potentially contribute significant amounts of carbon 9.02 for GWB and ERDA-6 brine, dioxide and leads to a model-predicted pH of 8.69 respectively." and 9.02 for GWB and ERDA-6 brine, respectively. To: DOE also states that the ERDA-6 pH is 9.02 in the "Under these repository-relevant conditions, text immediately following equation SOTERM.4. the model-predicted pH is 8.69 in GWB brine These statements appearto confuse the results of and 8.94for ERDA-6 brine. In both cases, FMT modeling for the CRA-2004 PABC and the this pH is established/buffered by the brucite CRA-2004 PA. The pH values of 8.69 and 8.94 for dissolution reaction." GWB and ERDA-6 brine, respectively, were obtained for microbial vectors with organic ligands for the CRA-2004 PABC. The pH values of 8.69 and 9.02 for GWB and ERDA-6 brine, respectively, were obtained for microbial vectors with organic ligands for the CRA-2004 PA. DOE should clarify this statement, in light ofthe fact that all vectors for the PABC were assumed to include microbial degradation of cellulose or cellulose, plastics, and rubber

Page 7 of 11Enclosure 3
And on page 10, line 36 to page 11 line 2 change: "Consideration ofthe possibility of high C02 levels leads to a calculated pH of 8.69 and 9.02 for GWB and ERDA-6 brine, respectively. This is a relatively small change in the predicted pH with no change predicted in GWB brine and only a 0.08 pH shift in ERDA-6 brine. These values offco2 and pH were used in the actinide speciation and solubility calculations for all CRA-2004 PABC vectors (Brush 2005)." To: "This value offco2 and a pH of 8.69 and 8.94 for GWB and ERDA-6 brine, respectively, were used in the actinide speciation and solubility calculations for all CRA-2004 PABC vectors (Brush 2005)."

Page 8 of 11Enclosure 3
13 EPA Comment 1-C-12 Chemistry Issues- In Appendix SOTERM, page 51, figure EPA LANL-Reed Included in 3rd Submitted to EPAI Stability and likelihood of Pu(lII) in Brine legend for Figure 11, change: Response in 3rd Response Submittal to the Nov 2009 In the caption for Appendix SOTERM-2009, Figure "Speciation Diagram for Plutonium in EPA SOTERM-11, DOE states that the Eh-pH diagram Carbonated Low-Ionic-Strength Groundwater demonstrates that Pu(lV) species would be stable (Based on Data Presented in Runde et al. at near-neutral pH. However, atthe reducing 2002). This Illustrates the Expected Lower conditions expected in the repository (nearthe Solubility of Reduced Pu, Shows Pu(lV) lower stability limitforwater), Pu(lIl) species Rather Than Pu(lll) Species at Near-Neutral appear to be the most stable (PuC03+ and pH, and Suggests That the Dominant Pu Pu(C03)2-). DOE should explain this apparent Species in the pH 8-9 Range are Hydrolytic discrepancy. Species with Lesser Contributions From Carbonate." To: "Speciation Diagram for Plutonium in Carbonated Low-Ionic-Strength Groundwater (Based on Data Presented in Runde et al. 2002). This Illustrates the Expected Lower Solubility of Reduced Pu(lll) and Pu(lV) , and Suggests That the Dominant Pu Species in the pH 8-9 Range are Hydrolytic Species with Lesser Contributions From Carbonate." 

# I

Page 9 of 11Enclosure 3

14 IEPA Comment 1-C-13 Chemistry Issues
- Data IThe specifics used to generate Figure request for Figure SOTERM-16 and error in Figure SOTERM-16 are discussed in more detail in reference Richmann et al. (2008) provided to DOE should provide the carbonate concentration, the EPA. The concentrations used in total americium concentration, and assumed ionic generating this Figure are the predicted strength for generation ofAppendix SOTERM- solubility ofIII actinides in the CRA-2004 2009, Figure SOTERM-16. In addition, DOE should PABC for reacted GWB brine. correct a typographical error in the figure, where the subscript "3" was omitted from Am(OH)3(s). IThe DOE agrees that the "3" was inadvertently omitted from Am(OH)3(s) in Figure SOTERM-16. In Appendix SOTERM, page 72, Figure SOTERM-16, change: IEPA LANL-Reed Included in 3rd ISubmitted to EPA Response in 3rd Response Submittal to the Nov 2009 EPA



## I

w i**-,~ !--?~~~---'-_.-**  ....._.".-_
........­ o , • 6 & \D oH
To: 

# i i 

## -'t 2S"C -....

, , ,

Page 10 of 11Enclosure 3
15 EPA Comment 1-C-14 Chemistry IssuesInconsistencies in Description of Organic Ligand Effects DOE states in Appendix SOTERM-2009, Section 4.6 that organic ligands do not significantly affect actinide solubilities, despite data presented in Appendix SOTERM-2009, Table SOTERM-19 showing that ligands increased the calculated +111 actinide solubilities by factors of 1.71 (GWB) and 3.32 (ERDA-6) and +V actinide solubilities by factors of 1.50 (GWB) and 1.53 (ERDA-6). This statement is also at odds with the assertion in SOTERM-3.7 that EDTA and citrate could potentially affect actinide solubilities in WIPP brines. DOE should correct this statement, especially in light ofthe data indicating that ligand concentrations in the inventory have increased significantly since the CRA-2004 PABC. In Appendix SOTERM, Section 4.6, page 79, line 27 change: 'The FMT calculations (Brush 2005) demonstrate that the solubility ofthe III and IV actinides was not significantly enhanced by complexation with acetate, citrate, EDTA, and oxalate at their maximum potential concentrations (Table SOTERM-19)". To: "The FMT calculations (Brush 2005) demonstrate that the solubility ofthe III and IV actinides are only slightly affected by organic complexation (Table SOTERM-19). The solubility ofthe III actinides was increased by a factor of 1.7 in GWB and 3.3 in ERDA-6 brine. In both brines the solubility ofthe IVactinides was decreased by organic complexation. The overall effect ofthese changes on the release of actinides is not considered significant." EPA LANL-Reed Included in 3rd Response Submittal to the EPA Submitted to EPA in 3rd Response Nov 2009

Page 11 of 11WIPP CRA-2009 Comments and Responses Enclosure 4

EPA Comment Included in this Submittal Previously Submitted Pending

Comments Received May 21, 2009
1-G-l Stakeholder-Water Flow Model Concerns
- ext from the Citizens for Alternatives to Radioactive Dumping (CARD) news release on March 25, 2009, raises questions

... ./
17G-2 Shielded Containers
- The shielded container planned change request has been an ongoing activity that was not completed before the CRA-2009 was received by EPA. ./
1-G-3 Inventory- As outlined in the Executive Summary of DOE/TRU2008-3379, Rev. 1 (ATWIR 2007), DOE has proposed that ATWIR 2008 be used as the inventory source... ./
1-23-1 New Compliant Performance Assessment
- EPA believes it is necessary to perform a new performance assessment to capture changes since the last recertification

... ./
1-23-2 Chemistry PA
- References from Appendix SOTERM-2009:
­ References from Appendix SOTERM-2009: Borkowski...; Lucchini...; Reed

...; Richmann

... ./
1-23-3 Chemistry PA- DOE summarizes thermodynamic data for the +111, +IV, and +V actinides that have become available since the CRA2004 PABC in Appendix SOTERM

... ./
1-23-4 Chemistry PA- AP-137 (Clayton 2008), includes the statement on pages 17 and 18that the ligand concentrations were expected to increase from the 2004 to 2007 inventories. ./
1-23-5 Chemistry PA- In Appendix SOTERM-2009, Section 3.3.2 and SOTERM-2009, Section 3.6.2, DOE states that the pcH oftheWIPP brines is expected to be approximately 8.7

... ./
1-23-6 Chemistry PA- DOE reports uranium (VI) solubility experiments in the absence ofcarbonate and ligands (Appendix SOTERM-2009, Section 3.3.2). 1-23-6 a. Ifthe experimental results in GWB are extrapolated to pcH 9.64, the Nd (III) solubility could be approximately two orders of magnitude greater ("'4 x 10-5 M) than the value

... ./
1-23-6 b. -Given the evidence that borate complexation appears to affect the +111 and +VI actinide solubilities, DOE should address whetherthe +IV actinide solubilities

... ./

1WIPP CRA-2009 Comments and Responses Enclosure 4

EPA Comment Included in this Submittal Previously Submitted Pending
1-23-6 c. -The current actinide solubility conceptual model includes the assumption that "The important ions in WIPP brines are H+, Na+, K+, Mg2+, OH-, CL-, C032-, S042-and Ca2+. ../**1-~-1** Chemistry Issues- DOE states thatthe characterization data for the Martin Marietta MgO has been obtained from a single lot (SL2980076) ofthis material (Appendix MgO-2009

... ../
1-C-2 Chemistry Issues- The reactivity test used for MgO material· acceptance was developed in 1997. At thattime, the MgO used as backfill had a lower reactivity, but was... ../
1-C-3 Chemistry Issues- Appendix PA-2009, Section 7.1.1 attributes slower changes in repository pressure after 2,000 years to cessation of room closure, slowing of brine inflow

... ../
1-C-4 Chemistry Issues- Appendix MASS-2009 and Appendix SOTERM2009 do not address the current assumption that plastic and rubber degradation (ifoccurring)

... ../
l-C-5 Chemistry Issues- It is stated in Appendix PA-2009, Section 2.3.1, that water is neithercreated norconsumed by microbial reactions. ../
1-C-6 Chemistry Issues- DOE should providejustification forthe statement in Appendix SOTERM-2009,Section 3.7 that "Ofthe four organic chelating agents considered, only citrate

... ../
l-C-7 Chemistry Issues- Appendix SOTERM-2009, l:able SOTERM-I, provides an incomplete list ofthe current chemistry model assu mptions. ../
1-C-8 Chemistry Issues- The fourth paragraph ofAppendix SOTERM2009, Section 2.3.2 states: "the expected pH, when little or no carbonate is**pres~nt,** is 8.69 in GWB brine and

... ../
1-C-9 Chemistry Issues- DOE**stat~.s** that carbonate complexation of Nd(lII) is unimportant at conditions expected in WIPP brines (Appendix SOTERM-2009, Section 3.6.2). ../
1-C-1O Chemistry Issues- n Appendix SOTERM-2009, Section 4.4, DOE states thatthe chemical potential (Ilo/RT) forTh(OH)4(s) was changed in the FMT database since the

... ../
1-C-11 Chemistry Issues-In Appendix SOTERM-2009, Section 4.4, DOE should explain what is meant by their statement that, "The effects of hydromagnesite and calcite

... ../

2WIPP CRA-2009 Comments and Responses Enclosure 4

EPA Comment Included in this Submittal Previously Submitted Pending
1-C-12 Chemistry Issues- n the caption for Appendix SOTERM-2009, Figure SOTERM-ll, DOE states that the Eh-pH diagram demonstrates that Pu(lV) species would be

... ./
1-C-13 Chemistry Issues- DOE should provide the carbonate concentration, total americium concentration, and assumed ionic strength for generation ofAppendix SOTERM-2009

... ./
1-C-14 Chemistry**Issues~** DOE states in Appendix SOTERM-2009, Section 4.6 that organic ligands do not significantly affect actinide solubilities, despite data presented in Appendix

... ./
1-C-15 Chemistry Issues- n Appendix SOTERM-2009, Table SOTERM21, the parameter descriptions for PHUMCIM and PHUMSIM indicate "actinide solubilities are inorganic only

... ./
1-C-16 Chemistry Issues-In Appendix SOTERM-2009, Section 2.4.1.1, DOE cites "degradation ofsolubilizing organic ligands, leading to lower actinide solubility" as a possible

... ./
1-C-17 Chemistry Issues -In Appendix SOTERM-2009, Section 2.3.2, Brush et al. (2006) is cited as part ofthe documentation for the CRA2004 PABC, but this report was... ./
1-C-18 Chemistry Issues
- In Appendix MgO-2009, Section 4.2.2, DOE claims that hydromagnesite will completely convert to magnesite during the 10,000 yearWIPP regulatory time

... ./
1-C-19 Chemistry Issues -In Appendix MgO-2009, Section 5.1, DOE states that the actinide solubilities in WIPP brines calculated for the CRA-2004 PA and CRA-2004 PABC ./
1-C-20 Chemistry Issues -In the discussion of MgO uncertainties (Appendix MgO-2009, Section 6.2.4.4), DOE .does not include the uncertainties associated with the

... ./
1-C-21 Chemistry Issues- Appendix PA-2009, Table PA-10 does not include units for the concentrations, which should be moles/L. ./
1-C-22 Chemistry Issues
- Appendix PA-2009, Section 4.9 includes a statement that releases are controlled almost entirely by direct releases to the surface as cuttings, cavings

... ./
1-C-23 Chemistry Issues
- To facilitate EPA's technical review, DOE should provide EPA with copies ofall FMT input and output files used to update the actinide solubility uncertainty

... ./

3WIPP CRA-2009 Comments and Responses Enclosure 4

EPA Comment Included in this Submittal Previously Submitted Pending
Comments Received July 16, 2009

2-G-4 Inventory-Quality Assurance Slgn-offs
- While reviewing some ofthe quality assurance documents used by the LANL-CO inventory team to develop, manipulate and

... ./
CARD 2009 Recertification Comments (as noted in the 1 St completeness letter) The group, Citizens Against Radioactive Dumping (CARD), has submitted a report entitled, "Proofof Rapid Rainwater Recharge atthe WIPP Site, ./

2-15-CARD-1 page 1, last line- CARD states, "This is why the proponents ofWIPP deny the existence of karst at the WIPP site. They argue, in effect, that WIPP is a karst-free island

... ./
2-15-CARD-2 page 2, first line- CARD states, "The supposed reliability ofthe Rustler Formation as a barrier to the migration of contaminated water hangs upon a postulated

... ./
2-15-CARD-3 page 2, third paragraph- CARD states, "Proof of rainwater recharge at the WIPP site would constitute proofthat WIPP is part of the regional karstland ofthe Pecos River.

.. ./
2-15-CARD-4 page 3, third paragraph- CARD states, "This is the very definition of karst. Simply stated, if rainwater recharge does reach the Culebra dolomite, the Culebra is not a... ./
2-15-CARD-5 page 4, paragraph 2-CARD states, "But the point to remember is this: none ofthis rainwater recharge is supposed to be happening. This invalidates the groundwater.

.. ./
2-15-CARD-6 page 14 last line-CARD states, "This strongly suggests that the water table will continue to rise at the WIPP site. Thus the Culebra is not in hydraulic steady state, as ... ./
2-15-CARD-7 page 30, first paragraph-CARD states, "If groundwater is supposed to be flowing from north to south, as DOE contends, how then did dissolved halite appear in these

... ./**2~15-CARD-8** page 36, 6th paragraph-CARD states in conclusion, Proof of rapid rainwater recharge at the WIPP site renders invalid the hydrologic model ofthe Culebra by which

... ./
2-C-24 Inventory-:-Chemistry
- The PA team requested data on the cement inventory as documented in PAIR 2008 (Crawford et al2009, Section 3.1). The scaled mass of cement was ... ./

4WIPP CRA-2009 Comments and Responses Enclosure 4

EPA Comment Included in this Submittal Previously Submitted Pending
2-23-7 Adequacy of Minimum Brine Calculations for Actinide Solubility Determinations The minimum brine volume is the volume of brine needed for a direct brine release (DBR) to
... ./
2-33-1 Please provide the following reference

... RL. Resources, Monthly Injection &Saltwater Report for

... ./
2-33-240 CFR 194.33(c)(2) states: (c) Performance" assessments shall document that in analyzing the consequences of drilling events, the Department assumed that.

..(2) Natural... ./
2-33-3 Dakota Salts, LLC, is a Denver based company that has proposed the use of Deep Salt Caverns for storage of compressed air generated by wind farms. Dakota Salts

... ./
2-33-4 Carbon sequestration is being assessed on a nationwide basis, including the Permian Basin (http://www.southwestcarbonpartnership.org). The Southwest.

.. ./
2-33-5 In CRA-2009, DOE changed the maximum time a DBR can occur from 11 days to 4.5 days. The maximum DBR duration is represented in PA by the parameter MAXFLOW

... ./
2-33-5 a. The South Culebra Bluff Blowout is cited as an inappropriate analogy for a WIPP brine release based on the formation encountered, downhole pressures anticipated

... ./
2-33-5 b. Review of drillers' comments (Memorandum, Document Number 545844) indicates that many drillers have never encountered a situation that would require mitigation of

... ./
2-33-5 c. Several drillers (reference 545844) indicated that they may never detect a brine release from the repository given the hypothetical release conditions posed by Kirkes (2007) ./
2-33-5 d. One driller interviewed in reference 545844 indicated that if a brine kick was encountered, he would probably let brine flow to surface without any attempt at mitigation

... ./
2-33-5 e. Additionally, it is unclear what effect brine shut-in would have with respect to duration offlow and downhole conditions. Please provide references that address the effects

.. ./
Comments Received October 19, 2009

5WIPP CRA-2009 Comments and Responses Enclosure 4

EPA Comment Included in this Submittal Previously Submitted Pending
3-24-1 Inventory (194.24) Table 5-4 of PAIR 2008 provides without comment a comparison ofwaste material parameters used in the PABC and PABC09 (the 2009 PABC). ../
3-C-25 Chemistry (C) Issues The Kd values used to model matrix actinide sorption during transport through the Culebra were based on the consideration ofexperimental data

... ../
3-23-8 FEPs"(194.23) The screening argument for FEP W45 is combined with that for FEPs W44 (Degradation of Organic Material) and W48 (Effects of Biofilms on Microbial Gas Generation),

... ../
3-23-9 EPA supports the systematic approach required by SP 9-4 and believes that itwill improve the maintenance, accuracy, and traceability of DOE's FEPs baseline. In reviewing SP 9-4,

... ../
3-23-10 Parameters (194.23) The focus of EPA's review ofthe CRA09 input files was on changes that occurred since the PABC 2004. Identified changes involving hard-coded numerical inputs included

... ../
3-23-11 Appendix PA-2009 states in Section PA-4.2.2, Initial Conditions, last paragraph, that the initial waste disposal area pressure is 1.01325 x 105 Pa, rather than the value of

... ../
3-23-12 Computer Codes A number of secondary computer codes are used to support CRA-2009. Please provide QA documentation for these codes that demonstrate they are reasonably qualified for use in PA. ../

6