WIPP CRA

‐ 2009 Comments and Responses Enclosure 4

EPA Comment Included in

this Submittal Previously

Submitted Pending

Comments Received May 21, 2009

1

‐ G

‐ 1 Stakeholder

‐ Water Flow Model Concerns
‐ ext from the Citizens

for Alternatives to Radioactive Dumping (CARD) news release on

March 25, 2009, raises questions... 9

1

‐ G

‐ 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. 9

1

‐ G

‐ 3 Inventory
‐ As outlined in the Executive Summary of DOE/TRU

‐

2008

‐ 3379, Rev. 1 (ATWIR 2007), DOE has proposed that ATWIR 2008

be used as the inventory source... 9

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... 9

1

‐ 23

‐ 2 Chemistry PA
‐ References from Appendix SOTERM

‐ 2009:
‐

References from Appendix SOTERM

‐ 2009: Borkowski...; Lucchini...;

Reed...; Richmann... 9

1

‐ 23

‐ 3 Chemistry PA
‐ DOE summarizes thermodynamic data for the

+111, +IV, and +V actinides that have become available since the CRA

‐

2004 PABC in Appendix SOTERM... 9

1

‐ 23

‐ 4 Chemistry PA
‐ AP

‐ 137 (Clayton 2008), includes the statement

on pages 17 and 18 that the ligand concentrations were expected to

increase from the 2004 to 2007 inventories. 9

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 of the WIPP

brines is expected to be approximately 8.7... 9

1

‐ 23

‐ 6 Chemistry PA
‐ DOE reports uranium (VI) solubility experiments

in the absence of carbonate and ligands (Appendix SOTERM

‐ 2009,

Section 3.3.2).

1

‐ 23

‐ 6 a. If the 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... 9

1

‐ 23

‐ 6 b.

‐ Given the evidence that borate complexation appears to

affect the +111 and +VI actinide solubilities, DOE should address

whether the +IV actinide solubilities... 9

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

‐ , CO32

‐ , SO42

‐ and Ca2+. 9

1

‐ C

‐ 1 Chemistry Issues
‐ DOE states that the characterization data for

the Martin Marietta MgO has been obtained from a single lot

(SL2980076) of this material (Appendix MgO

‐ 2009... 9

1

‐ C

‐ 2 Chemistry Issues
‐ The reactivity test used for MgO material

acceptance was developed in 1997. At that time, the MgO used as

backfill had a lower reactivity, but was... 9

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... 9

1

‐ C

‐ 4 Chemistry Issues
‐ Appendix MASS

‐ 2009 and Appendix SOTERM

‐

2009 do not address the current assumption that plastic and rubber

degradation (if occurring)... 9

1

‐ C

‐ 5 Chemistry Issues
‐ It is stated in Appendix PA

‐ 2009, Section

2.3.1, that water is neither created nor consumed by microbial

reactions. 9

1

‐ C

‐ 6 Chemistry Issues
‐ DOE should provide justification for the

statement in Appendix SOTERM

‐ 2009, Section 3.7 that "Of the four

organic chelating agents considered, only citrate... 9

1

‐ C

‐ 7 Chemistry Issues
‐ Appendix SOTERM

‐ 2009, Table SOTERM

‐ l,

provides an incomplete list of the current chemistry model

assumptions. 9

1

‐ C

‐ 8 Chemistry Issues
‐ The fourth paragraph of Appendix SOTERM

‐

2009, Section 2.3.2 states: "the expected pH, when little or no

carbonate is present, is 8.69 in GWB brine and... 9

1

‐ C

‐ 9 Chemistry Issues
‐ DOE states that carbonate complexation of

Nd(III) is unimportant at conditions expected in WIPP brines

(Appendix SOTERM

‐ 2009, Section 3.6.2). 9

1

‐ C

‐ 10 Chemistry Issues
‐ n Appendix SOTERM

‐ 2009, Section 4.4, DOE

states that the chemical potential (μo/RT) for Th(OH)4(s) was

changed in the FMT database since the... 9

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... 9

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

‐ 11, DOE states that the Eh

‐ pH diagram demonstrates

that Pu(IV) species would be... 9

1

‐ C

‐ 13 Chemistry Issues
‐ DOE should provide the carbonate

concentration, total americium concentration, and assumed ionic

strength for generation of Appendix SOTERM

‐ 2009... 9

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... 9

1

‐ C

‐ 15 Chemistry Issues
‐ n Appendix SOTERM

‐ 2009, Table SOTERM

‐

21, the parameter descriptions for PHUMCIM and PHUMSIM indicate

"actinide solubilities are inorganic only... 9

1-C-16 Chemistry Issues- In Appendix SOTERM-2009, Section

2.4.1.1, DOE cites "degradation of solubilizing organic ligands, leading

to lower actinide solubility" as a possible... 9

1-C-17 Chemistry Issues - In Appendix SOTERM-2009, Section 2.3.2,

Brush et al. (2006) is cited as part of the documentation for the CRA2004 PABC, but this report was... 9

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 year WIPP regulatory time... 9

1-C-19 Chemistry Issues - In A ppendix MgO-2009, Section 5.1, DOE

states that the actinide solubilitie s in WIPP brines calculated for the

CRA-2004 PA and CRA-2004 PABC 9

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... 9

1-C-21 Chemistry Issues- Appendix PA-2009, Table PA-10 does not

include units for the concentrations, which should be moles/L. 9

1-C-22 Chemistry Issues - Appendix PA-2009, Section 4.9 includes a

statement that releases are cont rolled almost entirely by direct

releases to the surface as cuttings, cavings... 9

1-C-23 Chemistry Issues - To facilitate EPA's technical review, DOE

should provide EPA with copies of all FMT input and output files used

to update the actinide solubility uncertainty... 9

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 Sign-offs - W hile reviewing some

of the quality assurance documents used by the LANL-CO inventory

team to develop, manipulate and... 9

CARD 2009 Recertification Co mments (as noted in the 1 s t

completeness letter) T he group, Citizens Against Radioactive Dumping

(CARD), has submitted a report entitled, "Proof of Rapid Rainwater

Recharge at the WIPP Site, 9

2-15-CARD-l page 1, last line- CARD states, "This is why the

proponents of WIPP deny the existence of karst at the WIPP site.

They argue, in effect, that WIPP is a karst-free island... 9

2-15-CARD-2 page 2, first line- CARD states, "The supposed reliability

of the Rustler Formation as a barrier to the migration of contaminated

water hangs upon a postulated... 9

2-15-CARD-3 page 2, third paragraph- CARD states, "Proof of

rainwater recharge at the WIPP site would constitute proof that WIPP

is part of the regional karstland of the Pecos River... 9

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... 9

2-15-CARD-5 page 4, paragraph 2-CARD st ates, "But the point to

remember is this: none of this rainwater recharge is supposed to be

happening. This invalidates the groundwater... 9

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... 9

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... 9

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 of the Culebra by which... 9

2-C-24 Inventory-Chemistry

‐ T he PA team requested data on the

cement inventory as documented in PAIR 2008 (Crawford et al 2009,

Section 3.1). The scaled mass of cement was... 9

4WIPP CRA

‐ 2009 Comments and Responses Enclosure 4

EPA Comment Included in

this Submittal Previously

Submitted Pending

2-23-7 Adequacy of Minimum Brine Calc ulations for Actinide Solubility

Determinations The minimum brine volume is the volume of brine

needed for a direct brine release (DBR) to... 9

2-33-1 Please provide the following reference... RL. Resources,

Monthly Injection & Saltwater Report for ... 9

2-33-2 40 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... 9

2-33-3 D akota Salts, LLC, is a Denver based company that has

proposed the use of Deep Salt Cave rns for storage of compressed air

generated by wind farms. Dakota Salts... 9

2-33-4 Carbon sequestration is being assessed on a nationwide basis,

including the Permian Basin

(http://www.southwestc arbonpartnership.or g). The Southwest... 9

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... 9

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... 9

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... 9

2-33-5 c. Several drillers (reference 545844) indicated that they may

never detect a brine release from t he repository given the hypothetical

release conditions posed by Kirkes (2007) 9

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... 9

2-33-5 e. Additionally, it is unclear what effect brine shut-in would have

with respect to duration of flow and downhole conditions. Please

provide references that address the effects.. 9

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 of waste material parameters used in the

PABC and PABC09 (the 2009 PABC). 9

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 of experimental data... 9

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),... 9

3-23-9 EPA supports the systematic approach required by SP 9-4 and

believes that it will improve the maintenance, accuracy, and

traceability of DOE's FEPs base line. In reviewing SP 9-4,... 9

3-23-10 Parameters (194.23) The focus of EPA's review of the CRA09

input files was on c hanges that occurred since the PABC 2004.

Identified changes involving hard-coded numerical inputs included... 9

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 10 5 Pa, rather than the value of ... 9

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 demonstra te they are reasonably qualified for use in

PA. 9

January 25, 2009 Follow

‐ up questions to issues first raised in EPA's

May 21, 2009 letter, comment 1

‐ 23

‐ 6

1. There seems to be a disconnect between the previous (CRA-2004

PABC) FMT modeling results and the experimental investigation of

Nd(III) solubilities. Borkowski et al. (2008) assumed that the stable

Nd(III) phase in the carbonat e system would be NdOHCO3(s). 9

2. The observed differences in the concentrations at similar pcH in

GWB and ERDA-6 brine are attributed to borate complexation. GWB

has approximately 2.5 times the borate concentration of ERDA-6

. 9

3. The ”shoulder" in the Nd concentration in ERDA-6 brine as a

function of increasing pcH was attributed by Borkowski et al. 2008 to

borate complexation. However, the reason for the decreasing Nd

complexation as a function of pcH above about 9.75 was not clear

. 9

4. If the trend in Nd concentrations in GWB (Figure 4-8) is simply

extrapolated up to pcH 9.4 (the pc H predicted by FMT modeling for

GWB brine in the repository), the Nd concentration could be as high

as 4 x 10-5 M, which is much higher than the concentrations... 9

6WIPP CRA

‐ 2009 Comments and Responses Enclosure 4

EPA Comment Included in

this Submittal Previously

Submitted Pending

5. When discussing possible effe cts of increased +III actinide

solubilities on PA during our call, a LANL staff member said that he

thought the increased ligands concentrations predicted for the CRA2009 PABC FMT calculations might have increased the +III... 9

6. Figure 4-9 presents Nd(III) solub ility data in GWB as a function of

pcH in the absence of carbonate. At pcH values of approximately 7.3

and 8.0, the concentrations meas ured in experiments approached

from undersaturation are higher by approximately an order of... 9

7. DOE's response to 1-23-6c dated November 25, 2009 statement

that "For the III actinides, the complexation of borate effectively

substitutes for the calculated effect of carbonate presently in the WIPP

model." 9

8. DOE should perform FMT calculations to predict the concentrations

of Nd(III) under the conditions of the Nd(III) solubility experiments in

the NaCl, GWB, and ERDA-6 brines. 9

9. Another question is related to the carbonate concentrations in the

experiments that they conducted. I understand that they spiked an

initial carbonate concentration into the solutions and used "gas-tight

polypropylene bottles" for the experiments. 9

Comments Received February 22, 2010

4-C-26 On page 12 of Borkowski et al. (2008), the americium-borate

species is represented as AmB(OH)4 +, but on page 46, the

neodymium-borate species are represented as NdB40 7+ and

Nd(B407)2-. DOE should address whether there is any basis for 9

4-C-27 DOE should address whether transformation of the initial

NdOHC03(s) in their experiments to Nd(OH)3(s) could have

substantially changed the carbon ate concentrations during the

undersaturation experiments, includi ng whether it was possible that 9

4-C-28 Figure 3-4 of Borkowski et al. (2008) shows the solution

concentrations of americium(lII) as a function ofpcH in the absence

and presence ofCO2, and the data are attributed to Kim et al. (1984).

However, examination of this reference shows that the reported 9

4-C-29 Figure 4-7 of Borkowski et al. (2008) shows the neodymium

concentration as a function of time in the undersaturation experiments

with GWB and carbonate. The data in this figure show that

neodymium concentrations increased rapidly after the start of the 9

4-C-30 On page 46 of Borkowski et al. (2008), it is stated that the

addition of carbonate to modeling calculations performed with

Geochemists Workbench led to a slight increase in the

d i t t i b fth f t i f th Nd2(C03)l 9

7WIPP CRA

‐ 2009 Comments and Responses Enclosure 4

8 EPA Comment Included in

this Submittal Previously

Submitted Pending

4-C-31 On page 46 of Borkowski et al. (2008), it is stated that the

addition of carbonate to modeling calculations performed with

Geochemists Workbench led to a slight increase in the

d i t t i b fth f t i f th Nd2(C03)l 9

4-C-32 On page 29 of Borkowski et al. (2008), it was stated that XRD

analysis ofNdOHC03(s) synthesized for the purpose of the

experiments confirmed the "predominance" of a neodymium mixed

hydroxy-carbonate phase. DOE s hould discuss whether any XRD 9

4-C-33 On page 35 of Borkowski et al. (2008), it was stated that

neodymium solubility was studied in 5 M NaCI at 10-2M total

carbonate concentration. DOE s hould explain why this carbonate

concentration was not liste d in the test matrices 9

4-C-34 Because the data in Figure 4-5 (neodymium(III) solubility in 5

M NaCI in the presence of carbon ate) were obtained over different

time periods and had different initial carbonate concentrations, it is

difficult to interpret these data. 9

4-C-35 A review of the recent literature regarding aqueous thorium

speciation in carbonate solutions indicates that the speciation selected

by the OECD critical review (Rand et al. 2009) is the most consistent

with the available data. 9

4-C-36 An experimental investigation reported by Altmaier et al.

(2004) has indicated that intrinsic thorium colloids (e igencolloids) can

form and remain stable at high ionic strength (up to 5 M NaCI or 4.5 M

MgCh). 9