ILAW Glass Testing for Disposal at IDF: Phase 1 Testing

Immobilized Low-Activity Waste Glass Release Data Package for the Integrated Disposal Facility Performance Assessment

“…1.8 × 10 -2 1.80 × 10 -3 (R 2 = 0.94) 0.42 ±0.02 64 ±2 1 1.2  10 -10 Pierce et al 2004(a) The K g value for LD6-5412 is from McGrail et al (1997), which states that value for chalcedony should be used; value given is K g at 15 °C for chalcedony from the Geochemist's Workbench database thermo.com.V8.R6+.dat (Aqueous Solutions LLC 2015). The K g values for LAWA44, LAWB45, and LAWC22 listed in this report are different from the values listed in Pierce et al 2004, which were subject to a calculation error as pointed out in Papathanassiu et al (2011). The error was associated with the use of the molecular weight for H 4 SiO 4 (96.11 g/mol) instead of the molecular weight for Si (28.09 g/mol) during the calculation of the Si activity, which resulted in a factor of ~3.422 miscalculation.…”

“…This error was identified first by Pierce et al 2004). Papathanassiu et al (2011). Therefore, the values listed in this report were adjusted by multiplying original values for LAWA44, LAWB45, and LAWC22 listed in Pierce et al (2004) by ~3 .422.…”

“…To obtain alteration phases that may form at longer times, PCT-B was performed at 90 °C and a variety of times, allowing the reaction products to accumulate in the aqueous phase and eventually form alteration products. The results have been documented in a series of reports (McGrail et al , 1998b(McGrail et al , 2000a(McGrail et al , 2001aPierce et al 2004Pierce et al , 2010aPierce et al , 2013Pierce et al , 2014Papathanassiu et al 2011) and represent more than 260 different glass compositions that were tested for up to ~11 years. The vast majority of the glasses tested using PCT-B and the corresponding characterization were documented in Papathanassiu et al (2011).…”

“…Two recent review articles by Gin et al (2013) and Vienna et al (2013a) summarized the state of the science. As shown by static dissolution test results ranging in composition from commercial glass to ILAW to vitrified HLW glass (Mišíková et al 2007;Papathanassiu et al 2011;Ebert 2014), aluminoborosilicate glass dissolution in a non-refreshed solution can be divided into three regimes or stages (Figure 3.1) that occur as the reaction proceeds (e.g., Stage I, II, and III): Briefly, Stage I represents the behavior of glass in an ideally dilute solution. In this case, hydrolysis occurs so rapidly that nearly all other mechanisms, with the possible exception of interdiffusion or ion exchange, are rendered irrelevant.…”

“…In this reaction, alkali in the glass are released into solution and replaced in the solid glass structure with an equimolar amount of a hydrogen-containing monovalent ion (H + or H 3 O + ). The rate of this ion-exchange reaction, referred to hereafter as r IEX , has been determined from SPFT for numerous glasses (McGrail et al 2001a,b,c;Pierce et al 2004;Papathanassiu et al 2011). Although ion exchange is recognized as a diffusive phenomenon (with a resulting release rate as a function of the square root of time), in a system with continuous flow of infiltration water and continuous dissolution, the rate of release due to diffusion reaches a steady state.…”