Radiation Effects in Ceramic Insulators

1994 ◽  
Vol 373 ◽  
Author(s):  
G P Pells
Keyword(s):  
Radiation Damage ◽  
Neutron Irradiation ◽  
Radiation Effects ◽  
Oxide Ceramics ◽  
Damage Mechanisms ◽  
Ceramic Insulators ◽  
Varying Mass

AbstractRadiation damage mechanisms in oxide ceramics are briefly discussed for irradiation by electrons, ions and neutrons. The effects of electron, ion and neutron irradiation on the evolution of the damage microstructure of MgO, A12O3 and MgAl2O4 are followed in detail. Particular attention is paid to differences in the microstructure produced by ions of varying mass and energy. The effects of damage microstructure on other properties are indicated.

scholarly journals Radiation damage mechanisms for luminescence in Eu-doped GaN

2007 ◽  
Vol 101 (5) ◽  
pp. 054902 ◽  
Author(s):  
J. W. Tringe ◽  
T. E. Felter ◽  
C. E. Talley ◽  
J. D. Morse ◽  
C. G. Stevens ◽  
...  
Keyword(s):  
Radiation Damage ◽  
Damage Mechanisms

Neutron Radiation Effects on Lubricants and O-Rings for Target and Accelerator Applications

2021 ◽  
Vol 1024 ◽  
pp. 127-133
Author(s):  
Matteo Ferrari ◽  
Aldo Zenoni ◽  
Yong Joong Lee ◽  
Alberto Andrighetto
Keyword(s):  
Gamma Radiation ◽  
Radiation Damage ◽  
Radiation Effects ◽  
Nuclear Reactor ◽  
Neutron Radiation ◽  
Radioactive Isotopes ◽  
Structural Level ◽  
Radiation Resistant ◽  
Under Construction ◽  
Neutron Radiation Effects

Lubricants and O-rings are necessarily used for the construction of many accelerator-driven facilities as spallation sources or facilities for the production of radioactive isotopes. During operation, such component will absorb high doses of mixed neutron and gamma radiation, that can degrade their mechanical and structural properties. Experimental radiation damage tests of these components are mandatory for the construction of the facility. Methodologies for irradiation in nuclear reactor mixed fields and post-irradiation examination of lubricating oils, greases and O-rings were developed and are here presented. Samples were characterized with standard mechanical and physical-chemical tests. Parametric studies on the dose rate effects have been performed on O-rings. A case studies for a specific O-ring application in a gate valve has been developed. Some of the tested samples showed a dramatic change of their properties with dose, while others remain stable. Results were collected on nine commercial greases, on one oil and on four commercial elastomeric O-rings. The most radiation resistant among the selected products are now considered for application in facilities under construction. The main mechanisms of neutron and gamma radiation damage on these polymers were investigated at the mechanical and structural level.

scholarly journals IDENTIFICATION AND VERIFICATION OF MATERIAL FUNCTIONS OF THE CREEP MODEL UNDER THERMAL RADIATION EFFECTS FOR AUSTENITIC STEEL 1X18H10T

2020 ◽  
Vol 82 (1) ◽  
pp. 89-99
Author(s):  
V.A. Gorokhov
Keyword(s):  
Experimental Data ◽  
Numerical Modeling ◽  
Creep Rate ◽  
Thermal Radiation ◽  
Neutron Irradiation ◽  
Radiation Effects ◽  
Thermal Creep ◽  
Creep Model ◽  
Material Functions ◽  
Good Agreement

In the present paper, on the basis of the information available in the scientific literature on the thermal creep rate of 1X18H10T austenitic steel under neutron irradiation conditions, the material functions of the thermal creep model implemented and verified in the framework of the certified software for numerical modeling of structural deformation under thermal and thermal radiation effects of UPAKS software are obtained and verified. The list of identifiable material functions of the thermal creep model includes: a function that characterizes the initial creep strain rate, referred to a unit stress level at a given temperature level and stress parameter; the radius of the creep surface, which is a function of temperature; the hardening function, characterizing the change in the initial creep rate from the hardening parameter at a given temperature; a function that takes into account the effect of a fast neutron flux on the creep rate at a given temperature. Using an analytical approximation of experimental data describing the rate of thermal creep of steels under neutron irradiation depending on the stresses, temperature, and flux of fast neutrons, we obtained relations for determining the values of all the functions of the thermal creep model. The value of the radius of the creep surface for a fixed temperature was determined from the condition that the creep deformation for a selected period of time and the neutron flux accumulated during this time will not exceed 0.2%. Using the UPAKS software, the creep model and the obtained material functions implemented in them, numerical simulation of the deformation of 1X18H10T steel under conditions of prolonged thermal load and neutron irradiation was performed. The results of numerical modeling are in good agreement with the analytical dependences that describe the creep of a given material under uniaxial SSS. A numerical creep simulation was also carried out under the assumption of the absence of neutron irradiation. As in the case of neutron irradiation, good agreement is obtained between the calculated and experimental data.

A Study of Radiation Effects in Curium-Doped Gd2Ti2O7 (Pyrochlore) and CaZrTi2O7 (Zirconolite)

1981 ◽  
Vol 11 ◽  
Author(s):  
J.W. Wald ◽  
P. Offemann
Keyword(s):  
Radiation Damage ◽  
Nuclear Waste ◽  
Radiation Effects ◽  
Laboratory Data ◽  
Primary Host ◽  
Waste Forms ◽  
Rare Earth Titanate ◽  
Effects Of Radiation ◽  
Similar Phase ◽  
Nuclear Waste Forms

Radiation effects studies in both glass and glass ceramic nuclear waste forms have identified a rare-earth titanate phase of the general formula (RE) 2Ti207 which is capable of acting as a host phase for actinides.1,2 Ringwood and co-workers3 have also proposed a structurally similar phase, zirconolite (CaZrTi2 07), as one of the primary host phases in the SYNROC waste form. Data from these and other previous studies, as well as mineralogical information available on these titanate phases, have not provided an unambiguous interpretation of the effects of radiation damage relative to nuclear waste forms. This paper reports new laboratory data concerning radiation damage effects in both of these phases.

A hypothetical stochastic mechanism of radiation effects in single cells

1981 ◽  
Vol 213 (1191) ◽  
pp. 139-160 ◽  
Keyword(s):  
Stochastic Model ◽  
Radiation Damage ◽  
Radiation Effects ◽  
Primary Particle ◽  
Single Cells ◽  
Living Cells ◽  
The Other ◽  
Mathematical Treatment ◽  
Secondary Particles ◽  
Stochastic Mechanism

This paper is a sequel to an earlier one (Neyman & Puri 1976), which deals with a hypothetical structural stochastic model of radiation effects in living cells. This model incorporates two important details of the mechanism overlooked in its mathematical treatment by the previous workers. The first is that the passage of a single ‘primary’ radiation particle generates a ‘cluster’ of secondaries which can produce ‘hits’ that damage the living cells. The second detail concerns the time scales of radiation damage and of the subsequent repair. The events of arrival of a primary particle, its generation of secondary particles and their causing ‘hits’ on the sensitive targets within the cells, all occur for all practical purposes instantly. On the other hand the subsequent changes in the damaged cell, such as repair, appear to require measurable amounts of time. While the biological and physical justifications for some of the underlying assumptions of the model were discussed in the previous paper referred to above, the present paper is concerned mainly with the mathematical details and also with how the model attempts to explain some of the empirical findings available in the literature.

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