Accelerated Testing of Waste forms using a Novel Pressurized Unsaturated flow (PUF) Method

1996 ◽  
Vol 465 ◽  
Author(s):  
B. P. McGrail ◽  
P. F. Martin ◽  
C. W. Lindenmeier
Keyword(s):  
Borosilicate Glass ◽  
Unsaturated Flow ◽  
Flow Behavior ◽  
Secondary Phase ◽  
Phase Precipitation ◽  
Barrier Materials ◽  
Batch Tests ◽  
Glass Corrosion ◽  
Waste Forms ◽  
Low Activity

ABSTRACTA new experimental technique has been developed to test waste forms and other proposed engineered-barrier materials under unsaturated conditions. Laboratory experiments using the pressurized unsaturated flow (PUF) apparatus have been performed with a Na-Ca-Al borosilicate glass being studied for immobilization of low-activity tank wastes and a reference borosilicate glass for immobilization of high-level wastes (SRL-202). A complex coupling between glass corrosion, secondary phase precipitation, and unsaturated flow behavior was observed. Precipitation of a family of Na-Ca-Al zeolites was also found to cause an acceleration in the reaction rate of the low-activity waste glass. This same effect was observed after approximately 1 year in high solid-to-liquid ratio batch tests but after only 12 days using the PUF method at the same temperature. The onset of secondary phase precipitation was tracked by monitoring changes in volumetric water content and by inline chemical analysis. Finally, elemental release of the major glass components and solution pH were found to differ under unsaturated flow-through conditions as compared with saturated, batch tests. These findings, while preliminary, have important implications for understanding and modeling glass corrosion behavior under unsaturated conditions.

scholarly journals Crystallization of rhenium salts in a simulated low‐activity waste borosilicate glass: Erratum

2021 ◽  
Vol 104 (6) ◽  
pp. 2908-2908
Author(s):  
Brian J. Riley ◽  
John S. McCloy ◽  
Ashutosh Goel ◽  
Martin Liezers ◽  
Michael J. Schweiger ◽  
...  
Keyword(s):  
Borosilicate Glass ◽  
Low Activity

The Use of Hot-Isostatic Pressing to Process Nuclear Waste Forms

2009 ◽  
Author(s):  
Martin W. A. Stewart ◽  
Sam A. Moricca ◽  
Tina Eddowes ◽  
Yingjie Zhang ◽  
Eric R. Vance ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Nuclear Waste ◽  
Borosilicate Glass ◽  
Hot Isostatic Pressing ◽  
Processing Technology ◽  
Nuclear Wastes ◽  
Isostatic Pressing ◽  
Waste Forms ◽  
Nuclear Waste Forms ◽  
Glass Viscosity

ANSTO has developed a combination of tailored nuclear waste form chemistries coupled with the use of flexible hot-isostatic pressing processing technology to enable the successful incorporation of problematic nuclear wastes into dense, durable monoliths. This combined package also enables the design of waste forms with waste loadings well in excess of those achievable via baseline melting routes using borosilicate glass, as hot-isostatic pressing is not constrained by factors such as glass viscosity, crystallisation and electrical conductivity. In this paper we will discuss some of our experiences with problematic wastes, namely plutonium wastes, sludges and HLW such as the Idaho calcines.

scholarly journals In situ nuclear-glass corrosion under geological repository conditions

2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Mathieu Debure ◽  
Yannick Linard ◽  
Christelle Martin ◽  
Francis Claret
Keyword(s):  
Pure Water ◽  
Secondary Phase ◽  
Predictive Modelling ◽  
Diffusion Experiment ◽  
Secondary Phases ◽  
Glass Corrosion ◽  
Geological Repository ◽  
High Level ◽  
Rock Supports

Abstract Silicate glasses are durable materials but laboratory experiments reveal that elements that derive from their environment may induce high corrosion rates and reduce their capacity to confine high-level radioactive waste. This study investigates nuclear-glass corrosion in geological media using an in situ diffusion experiment and multi-component diffusion modelling. The model highlights that the pH imposed by the Callovo–Oxfordian (COx) claystone host rock supports secondary-phase precipitation and increases glass corrosion compared with pure water. Elements from the COx rock (mainly Mg and Fe) form secondary phases with Si provided by the glass, which delay the establishment of a passivating interface. The presence of elements (Mg and Fe) that sustain glass alteration does not prevent a significant decrease in the glass-alteration rate, mainly due to the limited species transport that drives system reactivity. These improvements in the understanding of glass corrosion in its environment provide further insights for predictive modelling over larger timescales and space.

Ion Implantation Studies of Nuclear Waste Forms

1981 ◽  
Vol 6 ◽  
Author(s):  
Clyde J. M. Northrup ◽  
George W. Arnold ◽  
Thomas J. Headley
Keyword(s):  
Nuclear Waste ◽  
Borosilicate Glass ◽  
Alpha Decay ◽  
Lead Ions ◽  
Waste Form ◽  
Elastic Recoil ◽  
Elastic Recoil Detection ◽  
Waste Forms ◽  
Basic Studies ◽  
Nuclear Waste Forms

ABSTRACTThe first observations of physical and chemical changes induced by lead implantation damage and leaching are reported for two proposed U.S. nuclear waste forms (PNL 76–68 borosilicate glass and Sandia titanate ceramics) for commercial wastes. To simulate the effects of recoil nucleii due to alpha decay, the materials were implanted with lead ions at equivalent doses up to approximately 1 × 1019 a decays/cm3 . In the titanate waste form, the zirconolite, perovskite, hollandite, and rutile phases all exhibited a mottled appearance in the transmission electron microscope (TEM) typical of defect clusters in radiation damaged, crystalline solids. One titanate phase containing uranium was found by TEM to be amorphous after implantation at the highest dose. No enhanced leaching (deionized water, room temperature, 24 hours) of the irradiated titanate waste form, including the amorphous phase, was detected by TEM, but Rutherford backscattering (RBS) suggested a loss of cesium and calcium after 21 hours of leaching. The RBS spectra also indicated enhanced leaching from the PNL 76–68 borosilicate glass after implantation with lead ions, in general agreement with the observations of Dran, et al. [6,7] on other irradiated materials. Elastic recoil detection spectroscopy (ERD), used to profile hydrogen after leaching, showed penetration of the hydrogen to several thousand angstroms for both the implanted and unimplanted materials. These basic studies identified techniques to follow the changes that occur on implantation and leaching of complex amorphous and crystalline waste forms. These studies were not designed to produce comparisons between waste forms of gross leach rates.

The Expected Environment for Waste Packages in a Salt Repository

1983 ◽  
Vol 26 ◽  
Author(s):  
L. R. Pederson ◽  
D. E. Clark ◽  
F. N. Hodges ◽  
G. L. Mcvpy ◽  
D. Rai
Keyword(s):  
Rock Salt ◽  
Near Field ◽  
Materials Testing ◽  
Site Specific ◽  
Waste Package ◽  
Barrier Materials ◽  
Waste Forms ◽  
Temperature Irradiation ◽  
Salt Brine ◽  
Package Materials

ABSTRACTThis paper discusses results of recent efforts to define the very near-field (within approximately 2m) environmental conditions to which waste packages will be exposed in a salt repository. These conditions must be considered in the experimental design for waste package materials testing, which includes corrosion of barrier materials and leaching of waste forms. Site-specific brine compositions have been determined, and “standard” brine compositions have been selected for testing purposes. Actual brine compositions will vary depending on origin, temperature, irradiation history, and contact with irradiated rock salt. Results of irradiating rock salt, synthetic brines, rock salt/brine mixtures, and reactions of irradiated rock salt with brine solutions are reported.

Stability Analysis for Coupling Hydraulic-Mechanical Unsaturated Deposit Body under Rainfall Infiltration

2013 ◽  
Vol 838-841 ◽  
pp. 768-772
Author(s):  
Qiang Ren
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Safety Factor ◽  
Unsaturated Flow ◽  
Flow Behavior ◽  
Flow Theory ◽  
Rainfall Infiltration ◽  
Strongly Coupled ◽  
The Difference ◽  
Element Method

In view of the deficiency of traditional saturated soil theory analyzing seepage and stability of slope under rainfall infiltration, based on the saturated-unsaturated flow theory, considering the mechanical behavior of slope which strongly coupled with flow behavior, the hydraulic-mechanical coupled finite element method on the case of rainfall induced instability in deposit body in Front of gushui Dam are used. The safety factor is calculated based on stress field obtained from the finite element method, with modified unsaturated Mohr-Coulomb failure criterion. The influences of rainfall duration and rainfall intensity to stability of deposit body are analyzed; the difference between calculated safety factor based on unsaturated flow theory and saturated flow theory is discussed.

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