Investigations of the Solution Behaviour of NaCl in the Quinary System NaCl-KCl-MgCl2-MgSO4-H2O at Different Temperatures

1981 ◽  
Vol 11 ◽  
Author(s):  
R. ConRadt ◽  
H. Eengelke ◽  
A. Kaiser
Keyword(s):  
Rock Salt ◽  
Elevated Temperatures ◽  
High Level Waste ◽  
Waste Forms ◽  
Quinary System ◽  
Different Temperatures ◽  
High Level ◽  
Solution Behaviour

The German concept of high level waste final storage by the aid of waste glasses is based on rock salt formations as deposits. Investigations consider the accidental case of water entrance into the deposit where the waste forms then are exposed to highly concentrated salt brines at elevated temperatures and pressures.

Determination of the Corrosion Mechanisms of High-Level Waste Containing Glass

1981 ◽  
Vol 11 ◽  
Author(s):  
Horst Scholze ◽  
Reinhard Conradt ◽  
Heinrich Engelke ◽  
Hans Roggendorf
Keyword(s):  
Rock Salt ◽  
High Level Waste ◽  
Extreme Conditions ◽  
Safety Standard ◽  
Waste Forms ◽  
Corrosion Mechanisms ◽  
High Level

The German concept of high level waste final storage provides the use of certain glasses containing radioelement oxides as glass components. These waste forms are to be stored in rock salt formations in order to isolate the waste from the biosphere. The efficiency of this isolation is a most important question. The aim is to achieve a high safety standard that remains valid under extreme conditions such as the uncontrolled water entrance to the deposit.

Titanate Waste Forms for High Level Waste — An Evaluation of Materials and Processes

1981 ◽  
pp. 123-130 ◽  
Author(s):  
R. G. Dosch ◽  
A. W. Lynch ◽  
T. J. Headley ◽  
P. F. Hlava
Keyword(s):  
High Level Waste ◽  
Waste Forms ◽  
High Level

Performance of Borosilicate Glass High-Level Waste Forms in Disposal Systems

1986 ◽  
Vol 73 (2) ◽  
pp. 139-139
Author(s):  
Edward J. Hennelly ◽  
E. I. Du Pont de Nemours
Keyword(s):  
Borosilicate Glass ◽  
High Level Waste ◽  
Waste Forms ◽  
High Level

Dose-Dependence of Pb-Ion Implantation Damage in Zirconolite, Hollandite, and Zircon

1981 ◽  
Vol 11 ◽  
Author(s):  
T. J. Headley ◽  
G. W. Arnold ◽  
C. J. M. Northrup
Keyword(s):  
Radiation Damage ◽  
Structural Damage ◽  
Accelerated Aging ◽  
Dose Dependence ◽  
High Level Waste ◽  
Long Term Stability ◽  
Waste Forms ◽  
Recent Approach ◽  
High Level

The long-term stability of nuclear waste forms is an important consideration in their selection for safe disposal of radioactive waste. Stability against long-term radiation damage is particularly difficult to assess by short-term laboratory experiments. Much of the displacement damage in high-level waste forms will be generated by heavy recoil nuclei emitted during the α-decay process of long-lived actinide elements. Hence, an accelerated aging test which reliably simulates the α-recoil damage accumulated during thousands of years of storage is desirable. One recent approach to this simulation is to implant the waste form with heavy Pb-ions.I- 6 If the validity of this approach is to be fully assessed, two important questions which have not yet been investigated must be answered.(1) Is the structural damage, including cumulative effects, similar for irradiation by Pb-ions and a-recoil nuclei in a given material? (2) Is the dose-dependence of the accumulated damage similar? The purpose of this investigation was to assess the extent of these similarities in selected materials. We utilized transmission electron microscopy (TEM) to characterize the radiation damage and measure its dose-dependence.

Parametric Investigation of Rock Salt Behaviour Resulting from Disposal of High Level Radioactive Waste

1990 ◽  
Vol 212 ◽  
Author(s):  
D. Caramelle ◽  
M.T. Gaudez ◽  
J. Monig ◽  
G. Ouzounian ◽  
G. Simonet
Keyword(s):  
Grain Size ◽  
Rock Salt ◽  
Absorbed Dose ◽  
Gas Production ◽  
High Level Waste ◽  
Spent Fuel ◽  
Salt Composition ◽  
Gas Atmosphere ◽  
High Level ◽  
Fuel Elements

ABSTRACTThe liberation and generation of gases from rock salt due to heat and gamma irradiation is investigated in order to obtain some of the data needed for the development of the concept for the disposal of high level waste in rock salt.Our work is concerned with the influence of various parameters on gas production, e.g. salt composition and grain size, total absorbed dose, dose rate, temperature and gas atmosphere. Some of these parameters have not been studied previously in detail.The original gamma irradiator employing spent fuel elements and capable of exposing samples at temperatures up to 250°C will be described. Experimental results from some 150 experiments will be given. The two major gases found were CO2 and N2O.CO, H2, CH4, Hydrocarbons, CI2, HCl and SO2 were also detected. The dependence of the gas yields on the various parameters will be presented and discussed.

scholarly journals Stability of High-Level Waste Forms

2004 ◽  
Author(s):  
Theodore M Besmann ◽  
John D Vienna
Keyword(s):  
High Level Waste ◽  
Waste Forms ◽  
High Level

Disposal of high-level nuclear wastes: a geological perspective

1985 ◽  
Vol 49 (351) ◽  
pp. 159-176 ◽  
Author(s):  
A. E. Ringwood
Keyword(s):  
Elevated Temperatures ◽  
Great Majority ◽  
Nuclear Industry ◽  
High Level Waste ◽  
Public Confidence ◽  
Wide Range ◽  
Close Relatives ◽  
High Level ◽  
Drill Holes

AbstractMost countries intend to dispose of their high-level radioactive wastes by converting them into a solidified wasteform which is to be buried within the earth. SYNROC is a titanate ceramic wasteform which has been designed for this purpose on the basis of geochemical principles. It comprises essentially rutile TiO2, ‘hollandite’ Ba(Al,Ti)Ti6O16, zirconolite CaZrTi2O7, and perovskite CaTiO3. The latter three phases have the capacity to accept the great majority of radioactive elements occurring in high-level wastes into their crystal lattice sites. These minerals (or their close relatives) also occur in nature, where they have demonstrated their capacity to survive for many millions of years in a wide range of geological environments. The properties of SYNROC and the crystal chemistry of its constituent minerals are reviewed in some detail and current formulations of SYNROC are summarized. A notable property of SYNROC it its extremely high resistance to leaching by groundwaters, particularly above 100°C. In addition, it can be shown that the capacity of SYNROC minerals to immobilize high-level waste elements is not markedly impaired by high levels of radiation damage. Current investigations are focused on developing a satisfactory production technology for SYNROC and progress towards this objective is described. The high leach resistance of SYNROC at elevated temperatures increases the range of geological environments in which the waste may be finally interred; in particular, SYNROC is well adapted for disposal in deep drill-holes, both in continental and marine environments. The fact that SYNROC is comprised of minerals which have demonstrated long-term geological stability is significant in establishing public confidence in the ability of the nuclear industry to immobilize high-level wastes for the very long periods required.

Characterization of Mechanical Strengths for Simulated High-Level Waste Forms

1989 ◽  
Vol 176 ◽  
Author(s):  
Hiroshi Igarashi ◽  
Takeshi Takahashi
Keyword(s):  
Fracture Toughness ◽  
Glass Ceramic ◽  
Bending Strength ◽  
Liquid Waste ◽  
High Level Waste ◽  
Spent Fuel ◽  
High Level Liquid Waste ◽  
Waste Forms ◽  
High Level ◽  
Mechanical Strengths

ABSTRACTWaste forms have been developed and characterized at PNC (Power Reactor and Nuclear Fuel Development Corporation)to immobilize high-level liquid waste generated from the reprocessing of nuclear spent fuel.Mechanical strength tests were excecuted on simulated solidified highlevel waste forms which were borosilicate glass and diopside glass-ceramic. Commercial glass was tested for comparison. Measured strengths were three-point bending strength,uniaxial compressive strength,impact strength by falling weight method,and Vickers hardness. Fracture toughness and fracture surface energy were also measured by both notch-beam and indentation technique.The results show that mechanical strengths of waste glass form are similar and that the glass ceramic form has the higher fracture toughness.

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