scholarly journals The effect of gamma irradiation of the volatility and redox state of simulated DWPF high-level nuclear waste glasses

1993 ◽  
Author(s):  
J.R. Harbour ◽  
J.C. Marra ◽  
N.E. Bibler
Keyword(s):  
Gamma Irradiation ◽  
Nuclear Waste ◽  
Redox State ◽  
High Level Nuclear Waste ◽  
High Level

The reaction of reference commercial nuclear waste glasses during gamma irradiation in a saturated tuff environment

1988 ◽  
Vol 3 (3) ◽  
pp. 576-597 ◽  
Author(s):  
John K. Bates ◽  
William L. Ebert ◽  
Donald F. Fischer ◽  
Thomas J. Gerding
Keyword(s):  
Gamma Irradiation ◽  
Radiation Exposure ◽  
Nuclear Waste ◽  
Current Data ◽  
Solution Chemistry ◽  
Nuclear Waste Repository ◽  
Exposure Rate ◽  
Reaction Products ◽  
High Level Nuclear Waste ◽  
High Level

The effects of gamma irradiation on groundwater and the reaction between groundwater and glass have been investigated at radiation exposure rates of 2 × 105 1 × 103 and 0 R/h. These experiments, which bound the conditions that may occur in a high-level nuclear waste repository located in tuff, have been performed using the actinide-containing glasses ATM-lc and ATM-8, and have been performed for time periods up to 278 days. The experimental results indicate that when only the repository groundwater is present, the pH of the system remains near-neutral, regardless of the radiation field, due to the buffering capacity of the solution. When glass is added to the system, the subsequent reaction is governed by the solution chemistry, which results from a complex interaction between radiolysis products, glass reaction products, and groundwater components. While no long-term reaction trends have been extracted from the current data, it is noted that there are no outstanding differences in the reaction of the glasses as measured by the release of the soluble components B, Mo, and Na, as a function of radiation exposure rate. However, there is a marked difference in the amount of U, Np, and Pu released from the glasses as a function of radiation exposure rate. This difference can be correlated with the pH values of the leachate, with more basic solutions resulting in lower actinide release.

An Investigation into the Oxidation State of Molybdenum in Simplifies High Level Nuclear Waste Glass Compositions

2003 ◽  
Vol 807 ◽  
Author(s):  
R. J. Short ◽  
R. J. Hand ◽  
N. C. Hyatt
Keyword(s):  
Oxidation State ◽  
Nuclear Waste ◽  
Photoelectron Spectroscopy ◽  
Redox State ◽  
X Ray ◽  
Reducing Atmosphere ◽  
Spin Resonance ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Glass Compositions

The redox state of Mo in glasses containing simplified simulated high level nuclear waste (HLW) streams has been investigated using Electron Spin Resonance (ESR) and X-ray Photoelectron Spectroscopy (XPS). Melts performed in highly oxidising or neutral (air) atmospheres contained Mo6+, but our study indicates that the Mo can be at least partially reduced to Mo4+ or Mo3+ by melting in a reducing atmosphere. The implications for glasses containing a full simulated HLW stream are that the formation of detrimental crystalline phases containing Mo6+ upon heat treatment may be avoided by reducing the oxidation state of Mo during melting.

Molybdenum in Nuclear Waste Glasses - Incorporation and Redox state

2002 ◽  
Vol 757 ◽  
Author(s):  
R. J. Short ◽  
R. J. Hand ◽  
N. C. Hyatt
Keyword(s):  
Heat Treatment ◽  
Nuclear Waste ◽  
Redox State ◽  
Redox Conditions ◽  
Simplified Model ◽  
Glass Melts ◽  
Composition And Structure ◽  
Trivalent Cations ◽  
High Level Nuclear Waste ◽  
High Level

The composition and structure of the mixed metal molybdates that can form in simulated high level nuclear waste (HLW) glass melts have been studied. It was found that molybdates of a tetragonal scheelite type were formed upon heat treatment of the simulated glass samples (representative of the slow cools experienced by the real vitrified product), and that these compounds are capable of incorporating the majority of the mono, di, and trivalent cations that would be present in a real HLW glass. In addition, it has been shown that altering the redox conditions prevailing upon melting can promote or suppress crystallisation in simplified model waste glasses that contain molybdenum. Experiments to investigate the effect of redox conditions during melting of simulated HLW glass on molybdate formation are also reported.

Transmutation of high-level nuclear waste by means of accelerator driven system

2013 ◽  
Vol 3 (1) ◽  
pp. 60-69 ◽  
Author(s):  
Hamid Aït Abderrahim ◽  
Didier De Bruyn ◽  
Gert Van den Eynde ◽  
Sidney Michiels
Keyword(s):  
Nuclear Waste ◽  
Driven System ◽  
High Level Nuclear Waste ◽  
Accelerator Driven System ◽  
High Level
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