Failure mechanisms of high level nuclear waste forms in storage and geological disposal conditions

2011 ◽  
pp. 397-432 ◽  
Author(s):  
V.V. Rondinella
Keyword(s):  
Nuclear Waste ◽  
Failure Mechanisms ◽  
Geological Disposal ◽  
Waste Forms ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Nuclear Waste Forms

scholarly journals Ab Initio Investigation of Helium Mobility in La2Zr2O7 Pyrochlore

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 667
Author(s):  
Yanxia Lu ◽  
Qing Peng ◽  
Chenguang Liu
Keyword(s):  
Nuclear Waste ◽  
Density Functional ◽  
Minimum Energy ◽  
Elastic Band ◽  
Waste Forms ◽  
Band Method ◽  
And Migration ◽  
High Level ◽  
Migration Pathways ◽  
Nuclear Waste Forms

The α-decay of incorporated actinides continuously produces helium, resulting in helium accumulation and causing security concerns for nuclear waste forms. The helium mobility is a key issue affecting the accumulation and kinetics of helium. The energy barriers and migration pathways of helium in a potential high-level nuclear waste forms, La2Zr2O7 pyrochlore, have been investigated in this work using the climbing image nudged elastic band method with density functional theory. The minimum energy pathway for helium to migrate in La2Zr2O7 is identified as via La–La interstitial sites with a barrier of 0.46 eV. This work may offer a theoretical foundation for further prospective studies of nuclear waste forms.

scholarly journals Apatite- and Monazite-Bearing Glass-Crystal Composites for the Immobilization of Low-Level Nuclear and Hazardous Wastes

1995 ◽  
Vol 412 ◽  
Author(s):  
D. J. Wronkiewicz ◽  
S. F. Wolf ◽  
T. S. DiSanto
Keyword(s):  
Transition Metals ◽  
Nuclear Waste ◽  
Toxic Metals ◽  
Hazardous Wastes ◽  
Waste Streams ◽  
Waste Forms ◽  
Glass Crystal ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Crystal Composite

AbstractThis study demonstrates that glass-crystal composite waste forms can be produced from waste streams containing high proportions of phosphorus, transition metals, and/or halides. The crystalline phases produced in crucible-scale melts include apatite, monazite, spinels, and a Zr-Si-Fe-Ti phase. These phases readily incorporated radionuclide and toxic metals into their crystal structures, while corrosion tests have demonstrated that glass-crystal composites can be up to 300-fold more durable than simulated high-level nuclear waste glasses, such as SRL 202U.

The Effect of Chloride Concentration on Crevice Corrosion of some Welded Titanium Alloys

2008 ◽  
Vol 59 (2) ◽  
pp. 140-144
Author(s):  
Laurentiu Popa ◽  
Maria Radulescu ◽  
Alice Dinu ◽  
Lucian Velciu ◽  
Ioan Viorel Branzoi
Keyword(s):  
Waste Management ◽  
Titanium Alloys ◽  
Nuclear Waste ◽  
Crevice Corrosion ◽  
Chloride Concentration ◽  
Geological Disposal ◽  
Buffer Material ◽  
High Level Nuclear Waste ◽  
High Level

Geological disposal is identified by nearly all experts in the field of waste management as the only safe and sustainable option presently available, but the progress towards its implementation is slow. The nuclear waste must be safely storaged for hundreds of thousand years. Titanium alloys are some of the most promising candidates as container materials for the long-term disposal of high level nuclear waste (HLW) in rock salt formations. In the case of titanium waste containers, between the containers walls and the surrounding buffer material used to pack the disposal borehole some crevices can appear in the welded zone container/ shielding lid, under a biofilm etc. For this purpose we studied the effect of chloride concentration on crevice corrosion of some welded titanium alloys (Grade 2 and Grade 12, respectively) in chloride solutions at 90oC by electrochemical methods (Ecorr vs time, potentiodynamic tests).

Advanced Ceramics and Glass-Ceramics for Immobilisation of ILW and HLW

2012 ◽  
Vol 1475 ◽  
Author(s):  
E. R. Vance ◽  
M. W. A. Stewart ◽  
S. Moricca
Keyword(s):  
Nuclear Waste ◽  
Hot Isostatic Pressing ◽  
Glass Ceramics ◽  
Steady Increase ◽  
Waste Forms ◽  
Regulatory Guidelines ◽  
Small Footprint ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Interim Storage

ABSTRACTSince the 1970s there has been a steady increase in research on candidate ceramic and glass-ceramics for immobilisation of HLW and ILW, both from the aspects of crystal-chemical design and processing technology. The variety of ceramics and glass-ceramics designed for different types of HLW and ILW will be presented, notably those which are problematic for vitrification. Several of these materials are optimally processed by hot isostatic pressing (HIP), a technology which can consolidate calcined intermediate-level and high-level nuclear waste. Thus we are targeting such wastes for development of alternative waste forms. The essential process steps during the HIP cycle will be outlined. Effective consolidation of a wide variety of tailored glass-ceramic and ceramic waste forms has been demonstrated. The principal advantages of the HIP technology include negligible offgas during the high temperature consolidation step, relatively small footprint, and high waste/volume loadings. While it can be argued that the “nuclear waste problem” is essentially solved technically, at least with current regulatory guidelines, different perceptions of the “best” waste form and processing method for a given waste, together with the general current lack of agreed locations for final repositories, or even interim storage sites, create uncertainties.

Corrosion Testing of Stainless Steel-Zirconium:Metal Waste Forms

1999 ◽  
Vol 556 ◽  
Author(s):  
D. P. Abraham ◽  
L. J. Simpson ◽  
M. J. Devries ◽  
S. M. Mcdeavitt
Keyword(s):  
Stainless Steel ◽  
Spent Nuclear Fuel ◽  
Fission Products ◽  
Waste Form ◽  
Waste Forms ◽  
Immersion Corrosion ◽  
Corrosion Studies ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Nuclear Waste Forms

AbstractStainless steel-zirconium (SS-Zr) alloys have been developed as waste forms for the disposal of metallic waste generated during the electrometallurgical treatment of spent nuclear fuel. The waste forms incorporate irradiated cladding hulls, components of the alloy fuel, noble metal fission products, and actinide elements. The baseline waste form is a stainless steel- 15 wt% zirconium (SS-15Zr) alloy. This article presents microstructures and some of the corrosion studies being conducted on the waste form alloys. Electrochemical corrosio n, immersion corrosion, and vapor hydration tests have been performed on various alloy compositions to evaluate corrosion behavior and resistance to selective leaching of simulated fission products. The SS-Zr waste forms immobilize and retain fission products very effectively and show potential for acceptance as high-level nuclear waste forms.

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