Analysis of components from drip tests with ATM-10 glass

Abstract

DISCLAIMER 5.6. 7.8. 9.10. 11.12. 13.14. . LIST OF FIGURES (contd.)Title LIST OF TABLES 1. 2.3. 4.5. 6. 7.8. 9. 10 ABSTRACTWaste package assemblies consisting of actinide-doped West Valley ATM-10 reference glass and sensitized 304L stainless steel have been reacted with simulated repository groundwater using the Unsaturated Test Method. Analyses of surface corrosion and reaction products resulting from tests that were terminated at scheduled intervals between 13 and 52 weeks are reported. Analyses reveal complex interactions between the groundwater, the sensitized stainless steel waste form holder, and the glass. Alteration phases form that consist mainly of smectite clay, brockite, and an amorphous thorium iron titanium silicate, the latter two incorporating thorium, uranium, arid possibly transuranics. The results from the terminated tests, combined with data from tests that are still ongoing, will help determine the suitability of glass waste forms in the proposed high-level repository at the Yucca Mountain Site. 1 2

Colloid-Associated Radionuclide Concentration Limits: ANL

“…The chemical compositions of the individual phases are characterized by the EDS spectra of Figure 16, while EELS analysis of REE and actinides in the brockite appears in Figure 17. The distribution of rare earths and actinides at 8 years is virtually identical to that observed in tests terminated after 1 year (Fortner et al , 1997a. At one year, very little spallation was observed in terminated test glass surfaces (Fortner et al , 1997a.…”

“…Growth occurs as the hydrated layer beneath the existing clay dissolves and the elements from solution saturate and reprecipitate onto the surface of the clay. This growth mechanism leads to the observed "backbone" structure of the clays in the N3 test glasses (Fortner et al 1997a). The very thin clay layers observed early in a test tend to have lattice planes somewhat oriented parallel with the surface, suggesting the original restructuring of the gel at the gel-water interface.…”

“…This layer may spall away, however, as stress builds up in the structure and as the glass etches away. This is likely the origin of the clay colloid particles observed in solution from the N3 Drip Tests (Buck and Bates 1999;Fortner et al , 1997aFortner et al , 1997bFortner and Bates 1996). December 2000 The apparent role of colloids in actinide release in the drip tests is illustrated in Figure 10.…”

“…Data used in these analyses include at least ten years of testing for the static glass tests (Ebert 1995;Buck and Bates 1999; DTN: LL991110251021.099), over ten years of testing for the glass drip tests Fortner et al 1997aFortner et al , 1997b; DTN: LL000205551021.118), and over four years of testing for the spent fuel tests (Finn et al 1994a(Finn et al , 1994b; DTN: LL991001251021.090). The methods employed for colloid characterization in this section are TEM and filtration (analysis of filtrates with inductively coupled plasma-mass spectrometry (ICP-MS) or alpha spectroscopy).…”

“…Additional air is also injected into the test vessel with the water. Details of the test procedure are given elsewhere (Fortner et al 1997a). Tests using actinide-and technetium-doped SRL 165 glass have been ongoing for over 12 years and are termed the N2 Tests.…”