Error # Error Description Correction Originator Responsibility 

1 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 of the solubilities used with these proportionality constants for the CRA-2004 PABC, and that the solubilities were calculated assuming equilibrium with brucite and hydromagnesite.

The description for PHUMCIM in Appendix SOTERM-2009, Table SOTERM-21 should be changed to “Proportionality constant for concentration of actinides 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)."

EPA LANL-Reed 

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

The description for PHUMSIM in Appendix SOTERM-2009, Table SOTERM-21 should be changed to “Proportionality constant for concentration of actinides associated with mobile humic colloids; in Salado brine;

EPA LANL-Reed 

CRA 2009 ErrataTracking

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 of the solubilities used with these proportionality constants for the CRA-2004 PABC, and that the solubilities were calculated assuming equilibrium with brucite and hydromagnesite.

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).”

Page 1 of 11
3 EPA comment 1-C-18

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 period. However, DOE's evaluation of the likely conversion of hydromagnesite to magnesite ignores information about this issue presented in SCA (2008). As part of a thorough evaluation of the likely conversion rate for hydromagnesite to magnesite, SCA (2008) cited data from Vance et al. (1992) that showed hydromagnesite can persist for as long as 6,200 years. In addition, DOE does not consider that slow CPR degradation will result in continuous brucite carbonation during the 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 for the 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 

The following statement should be added at the end of Subsection 4.2.2 of Appendix MgO 2009 to clarify the text in this subsection: “Based on the evidence discussed above, the DOE concludes that it is still unclear whether hydromagnesite will persist or convert to magnesite during the 10,000-year WIPP regulatory period. However, the EPA has specified that the brucite-hydromagnesite (5424) reaction be used to buffer the CO2 fugacity for compliance-related actinidesolubility calculations since the CCA PAVT (Trovato, 1997; U.S. EPA, 1998).”

EPA SNL-Brush 

be p ese t t e bac t oug out t eregulatory period.

Page 2 of 11
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(lV) model changed between these two PA calculations when the chemical potential (μ0/RT) for Th(OH)4(aq) was revised. On the other hand, the An(III) and An(V) solubility results changed because of a recalculation of ligand concentrations. EPA was not informed of any changes to the thermodynamic data for the An(III) 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 of changes 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 of an 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 of the inclusion of the solubility-limiting phase whewellite (Ca oxalate·2H2O) in the FMT database, which decreased the dissolved oxalate concentration despite an increase in the 

EPA SNL-Brush 

co ce t at o desp te a c ease t econcentration of oxalate prior to precipitation of whewellite (compare Brush and Xiong, 2005, Table 4, columns labeled “CRA-2004 PA” and “PABC”).

Page 3 of 11
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 of the 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 of the first paragraph of Subsection 6.2.4.4.1 of Appendix 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 chemical compositions of these materials.”

EPA SNL-Brush 

6 EPA comment 1-C-21

Appendix PA-2009, Table PA-10 does not include units for the concentrations, which should be moles/L

The units moles/L should be added to Appendix PA-2009, Table PA-10.

EPA SNL-Clayton 

7 EPA comment 1 EPA comment 1 C 22 - - In Appendix PA-2009, Section 4.9, page PA- EPA SNL-Clayton 

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 spallings. DOE should correct this statement to include cuttings, cavings, and direct brine release, as explained in Appendix PA-2009, Section 9.0.

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 Clayton 

8 EPA Comment 1-C-10 Chemistry Issues 

In 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 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 statement

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 

Page 4 of 11
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 of the 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 of the CCA PAVT. The second bullet in SOTERM-2009, Section 4.4 should be replaced with, “The dimensionless standard chemical potential for whewellite (CaC2O4•H20) was added to the database (Xiong 2004).”The first sentence in SOTERM-2009, Section 4.4 should read, “The version of the 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 

10 EPA Comment 1-C-17 Chemistry Issues – Proper 

Reference for Brush (2005) in Section 2.3.2In Appendix SOTERM-2009, Section 2.3.2, Brush et al. (2006) is cited as part of the documentation 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). 

The DOE agrees with this comment. Brush 2005 is the correct reference. This will be added to the errata list for Appendix SOTERM2009.

EPA LANL-Reed 

Page 5 of 11
11 EPA Comment 1-23-5 Chemistry Issues – 

Inconsistencies in pH in SOTERMIn 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 or 8.5. Based on FMT modeling performed for the CRA-2004 PABC, however, the pcH of GWB and ERDA-6 are expected to be 9.39 and 9.64, respectively. The pcH values cited by DOE seem to reflect the pH values of 8.69 and 8.94. DOE should correct the cited pcH values and reinterpret the solubility data in light of the correct values.

1) Change the following in Appendix SOTERM Section 3.3.2:“At the expected pCH+ in the WIPP (~8.7), the measured uranium solubility was between 10-7 M and 10-6 M.”To:“At the expected pCH+ in the WIPP (~9.5), the measured uranium solubility was between 10-7 M and 10-6 M.”2) Change the following in Appendix SOTERM Section 3.6.2:"The WIPP-relevant data summarized in this report support current PA calculations performed with the use of the Pitzer model (U.S. Department of Energy 2004, Appendix PA, Attachment SOTERM) for the values of 3 × 10-7 M and 1.7 × 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 of the Pitzer model 

EPA LANL-Reed 

pe o ed t t e use o t e t e ode(U.S. Department of Energy 2004, Appendix PA, Attachment SOTERM) for the values of 3 × 10-7 M and 1.7 × 10-7 M in GWB and ERDA-6, respectively, at pCH+~9.5."

Page 6 of 11
12 EPA Comment 1-C-8 Chemistry Issues – Issue of 

pH in microbial and non-microbial vectorsThe 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 8.94 for ERDA-6 brine. In both cases, this pH is established/buffered by the brucite dissolution reaction. The presence of microbial activity will potentially contribute significant amounts of carbon dioxide and leads to a model-predicted pH of 8.69 and 9.02 for GWB and ERDA-6 brine, respectively.DOE also states that the ERDA-6 pH is 9.02 in the text immediately following equation SOTERM.4. These statements appear to confuse the results of FMT modeling for the CRA-2004 PABC and the CRA-2004 PA. The pH values of 8.69 and 8.94 for 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 of the fact that all vectors for 

In Section 2.3.2, Page 10, line 12-16 of Appendix SOTERM change:  “Under these repository-relevant conditions, the expected pH, when little or no carbonate is present, is 8.69 in GWB brine and 8.94 for ERDA-6 brine. In both cases, this pH is established/buffered by the brucite dissolution reaction. The presence of microbial activity will potentially contribute significant amounts of carbon dioxide and leads to a modelpredicted pH of 8.69 and 9.02 for GWB and ERDA-6 brine, respectively.”To:“Under these repository-relevant conditions, the model-predicted pH is 8.69 in GWB brine and 8.94 for ERDA-6 brine. In both cases, this pH is established/buffered by the brucite dissolution reaction.”

EPA LANL-Reed 

t s state e t, g t o t e act t at a ecto s othe PABC were assumed to include microbial degradation of cellulose or cellulose, plastics, andrubber

Page 7 of 11
And on page 10, line 36 to page 11 line 2 change:“Consideration of the possibility of high CO2 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 of fCO2 and pH 

were used in the actinide speciation and solubility calculations for all CRA-2004 PABC vectors (Brush 2005).”To:“This value of fCO2 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 11
13 EPA Comment 1-C-12 Chemistry Issues – Stability 

and likelihood of Pu(III) in BrineIn the caption for Appendix SOTERM-2009, Figure SOTERM-11, DOE states that the Eh-pH diagram demonstrates that Pu(IV) species would be stable at near-neutral pH. However, at the reducing conditions expected in the repository (near the lower stability limit for water), Pu(III) species appear to be the most stable (PuCO3+ and Pu(CO3)2-). DOE should explain this apparent discrepancy.

In Appendix SOTERM, page 51, figure legend for Figure 11, change:“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, Shows Pu(IV) Rather Than Pu(III) Species at Near-Neutral pH, and Suggests That the Dominant Pu Species in the pH 8-9 Range are Hydrolytic 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(III) and Pu(IV), and Suggests That the Dominant Pu Species in the pH 8-9 Range are Hydrolytic Species with Lesser Contributions From Carbonate.”

EPA LANL-Reed 

Page 9 of 11
14 EPA Comment 1-C-13 Chemistry Issues – Data 

request for Figure SOTERM-16 and error in FigureDOE should provide the carbonate concentration, total americium concentration, and assumed ionic strength for generation of Appendix SOTERM-2009, Figure SOTERM-16. In addition, DOE should correct a typographical error in the figure, where the subscript "3" was omitted from Am(OH)3(s).

The specifics used to generate Figure SOTERM-16 are discussed in more detail in reference Richmann et al. (2008) provided to the EPA. The concentrations used in generating this Figure are the predicted solubility of III actinides in the CRA-2004 PABC for reacted GWB brine.The 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:To: 

EPA LANL-Reed 

o

Page 10 of 11
15 EPA Comment 1-C-14 Chemistry Issues – 

Inconsistencies in Description of Organic Ligand EffectsDOE 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 +III 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 of the 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 of the 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 of the III and IV actinides are only slightly affected by organic complexation (Table SOTERM-19). The solubility of the III actinides was increased by a factor of 1.7 in GWB and 3.3 in ERDA-6 brine. In both brines the solubility of the IV actinides was decreased by organic complexation. The overall effect of these changes on the release of actinides is not considered significant.”

EPA LANL-Reed 

Page 11 of 11