Savannah River Site - NRC

OSR 45-11(Rev 10-22-2008)

Savannah River Site

Supplier Document Status

1.Work May Proceed

2.Submit Final Document -Work may proceed

3.Revise and Resubmit - Workmay proceed subject to Resolution of Comments

4.Revise and Resubmit. Workmay not Proceed.

5.Permission to proceed isnot required.

Permission to proceed does not constitute acceptance or approval of design details, calculations, test methods, analysis or materials developed or selected by the supplier, and does not relieve supplier from full compliance with contractual obligations or release of any 'holds' placed on the contract.

Document ID

Document Category Date

Reviewer

Revision

8-ANALYSIS AND DESIGN REPORTS

SRRA099188-000003

2018-10-01 07:07:51 AM, EDT

KINARD, TIFFANY BROOKE

A

8-17-18 SREL Doc.: R-18-004 Ver. 1.0

1

Summary

Estimates of Technetium (Tc) solubility under conditions relevant to the Saltwaste Disposal Facility (SDF) were calculated using Geochemist’s Workbench (GWB), Release 11 (Bethke and Yeakel, 2018a, b, c, d) and PHREEQC (Parkhurst and Appelo, 1999). The Geochemist’s Workbench software has been previously validated to successfully implement the underlying theory and algorithms utilized in the current application (Pabalan and Sabido, 2007). Similar modeling efforts have been conducted by M. Denham (2008), Cantrell and Williams (2012), and Li and Kaplan (2013) using the GWB software package.

None of the widely available thermodynamic databases has all of the required constants

for both Tc aqueous species and solid phases of interest, i.e., TcO2-c(s), TcO2.1.6H2O(s) and

TcO2.2H2O(s). For the GWB calculations, the LLNL thermodynamic database

(thermos.com.V8.R6+.dat) was used with limited documented changes (see Appendix). The current modeling effort generally reflects the modified thermodynamic database utilized by Li and Kaplan (2013). Current Benchmark Examples

Table 1 provides results from a common solubility calculation for barite (BaSO4) that has been previously used to compare the results from different modeling efforts. The molar solubility and activity reported by Pabalan and Sabido (2007) and Li and Kaplan (2013) are consistent with current modeling results. Table 1. Solubility of barite in pure water.

Ba2+ (M) SO42- (M) Activity Ba Activity SO4

2- GWB Pro 11.0* 1.607x10-5 1.607x10-5 0.9701 0.9701 GWB 8.0** 1.607x10-5 1.607x10-5 0.9701 0.9701 GWB 6.0*** 1.607x10-5 1.607x10-5 0.9701 0.9701

*current work **(Li and Kaplan, 2013) ***(Pabalan and Sabido, 2007)

Figure 1 provides an initial benchmark example that is directly relevant to the current

modeling results, i.e. the stability diagram for TcO2.1.6H2O(s) as a function of pH at Eh = -0.4 V

under ideal conditions. The results are graphed in terms of the log activity of Tc, which is essentially the same as the total molar Tc solubility under these conditions. Similar diagram for TcO2-c(s) and TcO2

.2H2O(s) are provided later in the discussion below. The current phase diagram is consistent with previous results reported by Wang et al. (2009) and Li and Kaplan (2013). Furthermore, the molar solubility of TcO2.1.6H2O(s) and TcO2.2H2O(s) at fixed pH 8.0 and Eh =

8-17-18 SREL Doc.: R-18-004 Ver. 1.0

2

-0.4 V in pure water (Table 2) is identical the values reported by Li and Kaplan (2013) for the same conditions, i.e., 3.98 x 10-9 and 5.86 x10-9 mol L-1 Tc for TcO2

.1.6H2O(s) and TcO2.2H2O(s),

respectively. Note that in both instances, the precipitation of other potential Tc containing solid phases was suppressed so that results were limited to only the specific solid phase of interest. Figure 1. Benchmark example supporting current modeling efforts: stability of TcO2.1.6H2O(s) as a function of pH at Eh = -0.4 V (all other Tc minerals are suppressed).

Table 2. Solubility of TcO2.1.6H2O and TcO2.2H2O in pure water.

TcO2.1.6H2O TcO2

.1.6H2O TcO2.2H2O TcO2

.2H2O Database Li and Kaplan,

2013 This Work GWB Li and Kaplan,

2013 This Work GWB

pH 8 8 8 8 Eh (V) -0.4 -0.4 -0.4 -0.4 Other Tc Minerals

Suppressed Suppressed Suppressed Suppressed

Tc Solubility (M) 3.98E-09 3.98E-09 5.86E-09 5.86E-09 (Li and Kaplan, 2013)

8-17-18 SREL Doc.: R-18-004 Ver. 1.0

3

Solubility of TcO2·1.6H2O and TcO2·2H2O in Reducing Saltstone Leachates The solubility of TcO2

.1.6H2O(s), TcO2.2H2O(s), and TcO2(s) as a function of pH and Eh in

the presence of saltstone leachates was estimated using four different test chemistries (Table 3). Two of the leachate chemistries were based on data from Cantrell and Williams (2012) for crushed saltstone in contact with 0.005M Ca(OH)2 under anoxic conditions at day 14 and day 84 of a single-pass flow through experiment. Two additional leachate chemistries are based on chemical analysis of the first (1st PV DLM) and fifth (5th PV DLM) pore volume exchange of saltstone leachate from Savannah River Ecology Laboratory (SREL) Dynamic Leaching Method (DLM) experiments. Data from Cantrell and Williams (2012) were used for any missing analytes from the DLM data sets. It is interesting to note that the composition of the solutions from Cantrell and Williams (2012) are quite similar to the DLM leachates (“14 Day Saltwaste” vs. “1st PV DLM”; “84 Day Saltwaste” vs. “5th PV DLM”), especially with respect to the more soluble components, e.g., Na+, K+, NO3

-, and SO42-.

Table 3. Chemistry of Saltstone pore solutions used in estimating Tc solubility. Component 14 Day

Saltwaste* 1st PV DLM *** 84 Day

Saltwaste** 5th PV DLM ***

CO3

2- (mg/L) 4,344 6,000 2,685 2,685** Al3+ (µg/L) 61,500 5,450 76,500 76,500** H3BO3 (µg/L) 22,019 22,000* 14,735 14,735** Ca2+ (µg/L) 11,000 3,200 2,428 2,428** Fe(II) (µg/L) 2,360 500 6,440 6,440** Li+ (µg/L) 4,780 4,780* 3,640 3,640** Mg2+ (µg/L) 800 MoO42- (µg/L) 7,166 7,166* 747 747** K+ (µg/L) 2.42E+06 2.00E+06 3.71E+05 2.00E+05 H4SiO4 (µg/L) 134,437 1.00E+05 2.46E+05 2.46E+05** Na+ (µg/L) 3.89E+07 3.95E+07 6.13E+06 6.00E+06 SO4

2- (mg/L) 4,790 6,000 345 345** NO3

- (mg/L) 7.79E+04 6.52E+04 9.03E+03 9.78E+03 PO4

3- (µg/L) 6,834 1,300 5.66E+03 5.66E+03** pH 12.66 12.75 12.74 10.5 Eh -0.38 -0.38 -0.30 -0.4 to -0.1

*(Cantrell and Williams, 2012) 14 Day Saltwaste **(Cantrell and Williams, 2012) 84 Day Saltwaste ***Based on the chemical analysis of Saltstone leachate for SREL DLM testing. Note that when experimental data was not available for “DLM Effluent 1 PV” and “DLM Effluent 5 PV”, data from “14 Day Saltwaste” and “84 Day Saltwaste” was used, respectively.

8-17-18 SREL Doc.: R-18-004 Ver. 1.0

4

Initial estimates of Tc solubility for TcO2.1.6H2O(s) in the fourteen day saltstone leachate

(fixed pH 12.66 and Eh -0.38 V) from Cantrell and Williams (2012) are provided in Table 4. The results are reported in terms of total Tc in solution, regardless of aqueous Tc speciation. Solubility estimates from previous modeling efforts are provided for comparison. Current estimates are a bit higher than Li and Kaplan (2013) and Denham (2008), but very similar to Cantrell and Williams (2012).

Table 4. Solubility of TcO2.1.6H2O in reducing saltstone leachate (“14 day Saltwaste” from Cantrell and Williams, 2012).

TcO2.1.6H2O

Database This work GWB Li and Kaplan, 2013

Cantrell Denham

pH 12.66 12.66 12.66 12.66 Eh (V) -0.38 -0.38 -0.38 -0.38 Other Tc Minerals


Total Tc Solubility (M)

1.19E-06 6.33E-07 1.19E-06 6.33E-07

*(Li and Kaplan, 2013) **(Cantrell and Williams, 2012) ***(Denham, 2008)

Estimates of Tc solubility for TcO2

.1.6H2O(s) and TcO2.2H2O(s) as a function of pH at a

fixed Eh -0.38V for the 14 Day Saltwaste (Table 3) are provided in Tables 5 and 6. As above, the results are reported in terms of total Tc in solution, regardless of aqueous Tc speciation. As expected, the solubility of Tc decreases with decreasing pH over the conditions tested, with TcO2

.2H2O(s) being slightly more soluble than TcO2.1.6H2O(s). As noted previously, the current

results are a bit higher than Li and Kaplan (2013) and very similar to Cantrell and Williams (2012).

8-21-18 SREL Doc.: R-18-004 Ver. 1.0

5

Table 5. Solubility of TcO2.1.6H2O in reducing Saltstone leachate (Eh = -0.38) as a function of changing pH.

Database This work GWB

Li and Kaplan, 2013

Cantrell This work GWB

Li and Kaplan, 2013


Li and Kaplan, 2013

Cantrell

pH 11.8 11 10.5 Eh (V) -0.38 -0.38 -0.38 -0.38 -0.38 -0.38 -0.38 -0.38 -0.38 Other Tc Minerals

Suppressed Suppressed Suppressed Suppressed Suppressed Suppressed Suppressed Suppressed Suppressed


1.01E-07 4.24E-08 9.92E-08 2.12E-08 9.45E-09 2.16E-08 1.12E-08 5.20E-09 1.16E-08

*(Li and Kaplan, 2013) **(Cantrell and Williams, 2012) Table 6. Solubility of TcO2.2H2O in reducing Saltstone leachate (Eh = -0.38) as a function of changing pH.

Database This work GWB

Li and Kaplan, 2013


Li and Kaplan, 2013


Li and Kaplan, 2013

Cantrell

pH 11.8 11 10.5 Eh (V) -0.38 -0.38 -0.38 -0.38 -0.38 -0.38 -0.38 -0.38 -0.38 Other Tc Minerals

Suppressed Suppressed Suppressed Suppressed Suppressed Suppressed Suppressed Suppressed Suppressed

Tc Solubility (M)

1.50E-07 6.37E-08 4.05E-07 3.30E-08 1.42E-08 8.65E-08 1.81E-08 7.80E-09 4.64E-08

*(Li and Kaplan, 2013) **(Cantrell and Williams, 2012)

8-21-18 SREL Doc.: R-18-004 Ver. 1.0

6

A comparison of TcO2.1.6H2O(s), TcO2

.2H2O(s), and TcO2(s) solubility in three different leachates (see Table 3) is provided in Tables 7, 8 and 9. All are reported in terms of total Tc in solution, regardless of aqueous Tc speciation. As expected, the TcO2(s) is more insoluble than either TcO2

.1.6H2O(s) or TcO2.2H2O(s) under the conditions tested. The higher Tc solubility

calculated for the 84 Day Saltwaste solution compared to the DLM and 14 Day Saltwaste solutions is largely the impact of the higher Eh and pH conditions, as the solubility of the three Tc solid phases is highly sensitive to pH and Eh in that region of the stability field. Table 7. Solubility of TcO2.1.6H2O in reducing saltstone leachate: “14 Day Saltwaste”, “84 Day Saltwaste”, and “1st PV DLM”.

TcO2.1.6H2O

Database This work GWB This work GWB This work GWB Solution 14 Day Saltwaste 84 Day Saltwaste 1st PV DLM pH 12.66 12.74 12.75 Eh (V) -0.38 -0.30 -0.38 Other Tc Minerals Suppressed Suppressed Suppressed Total Tc Solubility (M)

1.19E-06 1.08E-02 2.23E-06

Table 8. Solubility of TcO2.2H2O in reducing saltstone leachate: “14 Day Saltwaste”, “84 Day Saltwaste”, and “1st PV DLM”.

TcO2.2H2O

Database This work GWB This work GWB This work GWB Solution 14 Day Saltwaste 84 Day Saltwaste 1st PV DLM pH 12.66 12.74 12.75 Eh (V) -0.38 -0.30 -0.38 Other Tc Minerals Suppressed Suppressed Suppressed Total Tc Solubility (M)

1.75E-06 1.58E-02 3.29E-06

Table 9. Solubility of TcO2(s) reducing saltstone leachate: “14 Day Saltwaste”, “84 Day Saltwaste”, and “1st PV DLM”.

TcO2(s) Database This work GWB This work GWB This work GWB Solution 14 Day Saltwaste 84 Day Saltwaste 1st PV DLM pH 12.66 12.74 12.75 Eh (V) -0.38 -0.30 -0.38 Other Tc Minerals Suppressed Suppressed Suppressed Total Tc Solubility (M)

1.20E-10 1.10E-6 2.26E-10

8-21-18 SREL Doc.: R-18-004 Ver. 1.0

7

Tables 10, 11, and 12 provide the solubility for TcO2

.1.6H2O(s), TcO2.2H2O(s), and TcO2(s)

in the 5th PV DLM solution (see Table 3) at Eh values of -0.4, -0.3, -0.2, and -0.1 V. All are reported in terms of total Tc in solution, regardless of aqueous Tc speciation. As expected, the TcO2(s) is more insoluble than either TcO2

.1.6H2O(s) or TcO2.2H2O(s) under the conditions tested.

Table 10. Solubility of TcO2.1.6H2O(s) in reducing Saltstone leachate “5th PV DLM” as a function of changing Eh.

Leachate 5 PV DLM pH 10.5 Eh (V) -0.4 -0.3 -0.2 -0.1 Other Tc Minerals



9.39E-09 9.39E-09 1.41E-06 0.1684

Table 11. Solubility of TcO2.2H2O(s) in reducing Saltstone leachate “5th PV DLM” as a function of changing Eh.




1.55E-08 1.55E-08 2.08E-06 0.2503

Table 12. Solubility of TcO2(s) in reducing Saltstone leachate “5th PV DLM” as a function of changing Eh.




7.13E-13 7.13E-13 1.43E-10 1.68E-05

8-21-18 SREL Doc.: R-18-004 Ver. 1.0

8

What follows is a series of stability and solubility diagrams for TcO2.1.6H2O(s),

TcO2.2H2O(s), and TcO2(s) that graphically illustrate the impact of pH and Eh on Tc solubility.

For the stability diagrams, the results are reported in terms of the log molar activity of Tc as a function of pH at a set Eh under ideal conditions, i.e., ionic strength ≈ 0. As such the molar activity for Tc is essentially the same as the total molar Tc in solution. In addition to the stability diagrams for each solid phase, the direct Tc solubility was calculated over a range of pH conditions in three different test solution cases, i.e., Ideal (i.e., ionic strength ≈ 0), 1st PV DLM and 5th PV DLM (Table 3), at different fixed Eh values. The results are reported in terms of total molar Tc in solution, regardless of aqueous Tc speciation. These diagrams clearly illustrate the impact of pH and Eh on Tc solubility across a range of conditions. However, the impact of ionic strength on Tc solubility is much less obvious when plotted in terms of log Tc mol L-1. Although it is difficult to tell, Tc solubility for all three phases increases from the Ideal case to the 5th PV DLM solution and then the more concentrated 1st PV DLM solution, reflecting the impact of ionic strength on the Tc activity in solution.

Stability Diagrams for TcO2.1.6H2O as a Function of Eh Figure 1. Speciation and solubility of TcO2

.1.6H2O(s) at an Eh of -0.4 V (all other Tc minerals suppressed). Note that activity of Tc is essentially the same

8-21-18 SREL Doc.: R-18-004 Ver. 1.0

9

Figure 2. Speciation and solubility of TcO2.1.6H2O(s) at an Eh of -0.3 V (all other Tc minerals

suppressed).


suppressed).

8-21-18 SREL Doc.: R-18-004 Ver. 1.0

10


suppressed).

TcO2.1.6H2O Solubility as a Function of Eh Figure 5. Solubility of TcO2

.1.6H2O(s) as a function of Eh (Ideal-Dilute Condtions) (all other Tc minerals suppressed).

7 8 9 10 11 12 13 141E-9

1E-8

1E-7

1E-6

1E-5

1E-4

0.001

0.01

0.1TcO2

.1.6H2O(s)

-0.4 V -0.3 -0.2 -0.1

Tc (m

ol/L

)

pH

8-21-18 SREL Doc.: R-18-004 Ver. 1.0

11

Figure 6. Solubility of TcO2.1.6H2O(s) as a function of Eh (1st PV DLM) (all other Tc minerals

suppressed).

Figure 7. Solubility of TcO2

.1.6H2O(s) as a function of Eh (5th PV DLM) (all other Tc minerals suppressed).

8 10 12 1410-9

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

TcO2.1.6H2O(s)

-0.4 V -0.3 -0.2 -0.1

Tc (m

ol/L

)

pH

7 8 9 10 11 12 13 141E-9

1E-8

1E-7

1E-6

1E-5

1E-4

0.001

0.01

0.1

-0.4 V -0.3 -0.2 -0.1

Tc (m

ol/L

)

pH

TcO2.1.6H2O(s)

8-21-18 SREL Doc.: R-18-004 Ver. 1.0

12

Stability Diagrams of TcO2.2H2O as a Function of Eh Figure 1. Speciation and solubility of TcO2

.2H2O(s) at an Eh of -0.4 V(all other Tc minerals suppressed).

Figure 2. Speciation and solubility of TcO2.2H2O(s) at an Eh of -0.3 V (all other Tc minerals

suppressed).

8-21-18 SREL Doc.: R-18-004 Ver. 1.0

13


suppressed).


suppressed).

8-21-18 SREL Doc.: R-18-004 Ver. 1.0

14

TcO2.2H2O Solubility as a Function of Eh Figure 5. Solubility of TcO2

.2H2O(s) as a function of Eh (Ideal-Dilute Condtions) (all other Tc minerals suppressed).

Figure 6. Solubility of TcO2

.2H2O(s) as a function of Eh (1st PV DLM) (all other Tc minerals suppressed).

7 8 9 10 11 12 13 141E-9

1E-8

1E-7

1E-6

1E-5

1E-4

0.001

0.01

0.1TcO2

.2H2O(s)

-0.4V -0.3 V -0.2 V -0.1V

Tc (m

ol/L

)

pH

7 8 9 10 11 12 13 141E-9

1E-8

1E-7

1E-6

1E-5

1E-4

0.001

0.01

0.1TcO2

.2H2O(s)

-0.4V -0.3 V -0.2 V -0.1V

Tc (m

ol/L

)

pH

8-21-18 SREL Doc.: R-18-004 Ver. 1.0

15

Figure 7. Solubility of TcO2.2H2O(s) as a function of Eh (5th PV DLM) (all other Tc minerals

suppressed).

8 10 12 141E-9

1E-8

1E-7

1E-6

1E-5

1E-4

0.001

0.01

0.1

-0.4V -0.3 V -0.2 V -0.1V

Tc (m

ol/L

)

pH

TcO2.2H2O(s)

8-21-18 SREL Doc.: R-18-004 Ver. 1.0

16

Stability Diagrams of TcO2(s) as a Function of Eh Figure 1. Speciation and solubility of TcO2(s) at an Eh of -0.4 V (all other Tc minerals suppressed).

Figure 2. Speciation and solubility of TcO2(s) at an Eh of -0.3 V(all other Tc minerals suppressed).

8-21-18 SREL Doc.: R-18-004 Ver. 1.0

17

Figure 3. Speciation and solubility of TcO2(S) at an Eh of -0.2 V (all other Tc minerals suppressed).

Figure 4. Speciation and solubility of TcO2(s) at an Eh of -0.1 V (all other Tc minerals suppressed).

8-21-18 SREL Doc.: R-18-004 Ver. 1.0

18

TcO2(s) Solubility as a Function of Eh Figure 5. Solubility of TcO2(s) as a function of Eh (Ideal-Dilute Condtions) (all other Tc minerals suppressed).

Figure 6. Solubility of TcO2(s) as a function of Eh (1st PV DLM) (all other Tc minerals suppressed).

7 8 9 10 11 12 13 141E-14

1E-13

1E-12

1E-11

1E-10

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

0.01

0.1TcO2(s)

-0.4 V -0.3 -0.2 -0.1

Tc (m

ol/L

)

pH

7 8 9 10 11 12 13 141E-14

1E-13

1E-12

1E-11

1E-10

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

0.01

0.1TcO2(s)

-0.4 V -0.3 -0.2 -0.1

Tc (m

ol/L

)

pH

8-21-18 SREL Doc.: R-18-004 Ver. 1.0

19

Figure 7. Solubility of TcO2(s) as a function of Eh (5th PV DLM) (all other Tc minerals suppressed).

7 8 9 10 11 12 13 141E-14

1E-13

1E-12

1E-11

1E-10

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

0.01

0.1TcO2(s)

-0.4 V -0.3 -0.2 -0.1

Tc (m

ol/L

)

pH

8-21-18 SREL Doc.: R-18-004 Ver. 1.0

20

References

Bethke, C. M., and Yeakel, S. (2018a). Geochemist's Workbench Release 11. Aqueous Solutions LLC, Champaign, Illinois.

Bethke, C. M., and Yeakel, S. (2018b). "The Geochemist's Workbench Release 11: GWB Essentials Guide." Aqueous Solutions, LLC, Champaign, Illinois.

Bethke, C. M., and Yeakel, S. (2018c). "The Geochemist's Workbench Release 11: GWB Reaction Modeling Guide." Aqueous Solutions, LLC, Champaign, Illinois.

Bethke, C. M., and Yeakel, S. (2018d). "The Geochemist's Workbench Release 11: GWB Reference Manual." Aqueous Solutions, LLC, Champaign, Illinois.

Cantrell, K. J., and Williams, B. D. (2012). "Equilibrium Solubility Model for Technetium Release from Saltstone Bsed on Single-Pass Flow Eperiments." Pacific Northwest National Laboratory, Richland, Washington.

Denham, M. 2008. Thermodynamic and mass balance analysis of exspansive phase precipitation in saltstone. WSRC-STI-2008-00236, Savannah River National Laboratory, Aiken, SC.

Denham M., and M.R. Millings. 2012. Evolution of chemical conditions and estimated solubility controls on radionuclides in the residual waste layer during post-closure aging of high-level waste tanks. SRNL-STI-2012-00404, Savannah River National Laboratory, Aiken, SC.

Li, D., and Kaplan, D. I. 2013. Solubility of Technetium Dioxides (TcO2-c, TcO2.1.6H2O and

TcO2.2H2O) in Reducing Cementitious Material Leachates: A Thermodynamic

Calculation. SRNL-STI-2012-00769, Savannah River National Laboratory, Aiken, SC. Pabalan, R. T., and Sabido, L. M. (2007). "Software Validation Plan and Report for

Geochemist's Workbench Version 6.0 ". Center for Nuclear Waste Regulatory Analysis, San Antonio, TX.

Parkhurst, D., and Appelo, C. A. J. (1999). "User's Guide to PHREEQC (Version 2)- A computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations," Rep. No. Water Resources Investigations Report # 99-5259. U.S. Geological Survey, Denver, CO.

Wang L., Martens E., Jacques D., De Cannière P., Berry J., and Mallants D., Review of sorption values for the cementitious near field of a near surface radioactive waste disposal facility: Project near surface disposal of category A waste at Dressel, NIRASMP5-03 DATA-LT(NF), Version 1, 2009.

8-21-18 SREL Doc.: R-18-004 Ver. 1.0

21

Appendix: Thermodynamic database used in speciation and solubility calculations (298.15 K, 0.1 MPa, I = 0). Phases Reaction* Solid/Aqueous Log K* Log K** Ref*** HTcO4

- HTcO4 = H+ + TcO4- Aqueous 8.7071 LLNL data base

H2TcO4 2H+ + TcO42- = H2TcO4 Aqueous 9.0049 LLNL data base

TcO(OH)2 2H2O + TcO2+ = TcO(OH)2 + 2H+ Aqueous -3.3221 -4.00 Denham and Millings, 2012 (TcO(OH) 2) 2 4 H2O + 2TcO2+ = (TcO(OH)2)2 + 4H+ Aqueous -0.1271 LLNL data base

TcO2+ 3H+ + 1TcO4- = TcO2+ + 1.5H2O +0.75 O2 Aqueous -31.5059 -31.0434 LLNL data base

TcOOH+ 1TcO2+ + H2O = TcOOH+ + H+ Aqueous -1.1355 LLNL data base TcO(OH)3

- TcO+2 + 3H2O = TcO(OH)3- + 3H+ Aqueous -14.2221 -14.899 Cantrell and Williams, 2012

HTcO4 HTcO4 = H+ + TcO4- Solid 5.9566 LLNL data base

KTcO4 KTcO4 = K+ + TcO4- Solid -2.2667 LLNL data base

NaTcO4 NaTcO4 = Na+ + TcO4- Solid 1.5208 LLNL data base

Tc(OH)2 Tc(OH)2 + 3H+ + 0.25O2 = Tc3+ + 2.5H2O Solid 5.2714 LLNL data base Tc(OH)3 Tc(OH)3 + 3H+ = Tc3+ + 3H2O Solid -9.2425 LLNL data base

Tc3O4 Tc3O4 + 9H+ + 0.25O2 = 3Tc3+ + 4.5H2O Solid -19.2271 LLNL data base Tc4O7 Tc4O7 + 10H+ = + 2Tc3+ + 2TcO2+ + 5H2O Solid -26.0149 LLNL data base

TcO2:2H2O(am) TcO2:2H2O + 2H+ = TcO2+ + 3H2O Solid -4.2319 LLNL data base TcO3 TcO3 + H2O = TcO4

2- + 2H+ Solid -23.1483 LLNL data base TcOH TcOH + 3H+ + 0.5O2 = + Tc3+ + 2H2O Solid 24.9009 LLNL data base TcS2 TcS2 + H2O = + TcO2+ + 2HS- Solid -65.9742 LLNL data base TcS3 TcS3 + 4H2O = TcO4

2- + 3HS- + 5H+ Solid -119.5008 LLNL data base TcO2:1.6H2O(s) TcO2

+ + 2.6H2O = TcO2:1.6H2O + 2H+ Solid 4.8356 4.4001 Cantrell and Williams, 2012 Tc2S7 Tc2S7 +8 H2O = + 2TcO4

- + 7HS- + 9H+ Solid -230.2410 LLNL data base Tc2O7 Tc2O7 + H2O = + 2H+ + 2 TcO4

- Solid 13.1077 LLNL data base TcO2(s) TcO2 + 2H+ = TcO2+ + H2O Solid -8.3936 Denham and Millings, 2012

TcCO3(OH) 2(aq) TcO+2 + CO3- + H2O = TcCO3(OH) 2(aq) Aqueous -15.2522 Denham and Millings, 2012

TcCO3(OH) 3-(aq) TcO+2 + CO3

- + 2H2O = TcCO3(OH)3-(aq) + H+ Aqueous 6.9518 Denham and Millings, 2012

*Original equalibrium constants from LLNL database. **Alternate equalibrium constants used on current modeling effort. ***Reference source for equilibrium constants used in current modeling effort.

Documents

Savannah River Site - NRC