Extended Leach Testing of Simulated LAW Cast Stone Monoliths

Abstract

The term effective diffusion coefficient used in this report is called observed diffusion coefficient in EPA Method 1315 documents. ANSI/ANS16.1 uses the symbol D with no subscript and names D =effective diffusion coefficient. ASTM C1308 method uses the symbol D e and name effective diffusion coefficient. In some literature this parameter, the D e value in Equations 1 and 4 is called apparent diffusion coefficient, D a (see for example Grathwohl (1998). All three names are equivalent and are "quantified" in standard leach tests by Equations 2 and 4. De σ De σ 7d to 604/609 d 28 d to 63 d 28 d to 604/609 Avg. Avg. Avg. Monolith Tc(VII)

Evaluation of Technologies for Enhancing Grout for Immobilizing Hanford Supplemental Low-Activity Waste (SLAW)

“…With Hanford waste that contains non-pertechnetate, it is not known if the non-pertechnetate species will undergo this conversion, but is unlikely because it is already in a reduced oxidation state (i.e., Tc(I) vs. Tc(IV)). Indeed, simulant testing of a grout waste form containing a synthesized Tc(I) carbonyl complex indicated a ~10× increase in observed diffusivity for a Tc(I) species compared with Tc(VII) (Serne et al 2016b). It is key to the assumptions in this report that the 99-Tc speciation in tank waste is known and is present entirely as Tc(VII) pertechnetate.…”

“…The largest portion of this effort was summarized in fiscal year 2013 (FY13) when PNNL and SRNL teamed to evaluate the performance of the Cast Stone formulation for properties including waste composition, waste concentration as defined by sodium molarity, fly ash, and blast furnace slag sources, water-to-dry-mix ratios and scale up (Westsik et al 2013b). Other efforts included testing of formulation enhancements, characterizing the Cast Stone product from the engineering-scale demonstration, preparing and characterizing Cast Stone with actual radioactive waste using an adjusted Tank 50 sample from SRNL, and obtaining performance data on a cementitious waste form to support the IDF performance assessment (PA) (Asmussen et al 2016;Serne et al 2016;). These efforts were then followed by an evaluation of historical SLAW data against a performance metric for the IDF (Asmussen et al 2019a, summarized in Section 3.3 of this report).…”

Review of Cementitious Materials Development and Applications That Have Supported DOE-EM Missions: Waste Treatment, Conditioning, Containment Structures, Tank Closures, Facility Decommissioning, Environmental Restoration, and Structural Assessments

“…13,14 Laboratory testing over several years has resulted in many cementitious reagent (ordinary portland cement, blast furnace slag, and Class F fly ash) blends. [15][16][17][18][19][20][21][22][23] A dry blend similar to saltstone was developed, termed "Cast Stone" (formulation shown in Table 5), in 2005. 17 Other dry-blend proportions have been investigated 17,19,20 , as well as water to dry mix proportions.…”

“…[15][16][17][18][19][20][21][22][23] A dry blend similar to saltstone was developed, termed "Cast Stone" (formulation shown in Table 5), in 2005. 17 Other dry-blend proportions have been investigated 17,19,20 , as well as water to dry mix proportions. 19,21 The ratio of water to cementitious materials has been tested over the range of 0.4-0.6.…”

“…17 Other dry-blend proportions have been investigated 17,19,20 , as well as water to dry mix proportions. 19,21 The ratio of water to cementitious materials has been tested over the range of 0.4-0.6. Testing with the use of "getters" (materials to lower the mobility of technetium or iodine) has been conducted as well.…”