scholarly journals A Rate Theory Model of Radiation-Induced Swelling in an Austenitic Stainless Steel

2021 ◽  
Vol 2 (4) ◽  
pp. 484-515
Author(s):  
Malcolm Griffiths ◽  
Juan Ramos-Nervi ◽  
Larry Greenwood
Keyword(s):  
Stainless Steel ◽  
Model Development ◽  
Theory Model ◽  
Rate Theory ◽  
Published Data ◽  
The Past ◽  
Void Swelling ◽  
Microstructure Parameters ◽  
Radiation Induced ◽  
Standard Rate

Many rate theory models of cavity (void) swelling have been published over the past 50 years, all having the same, or similar, structures. A rigorous validation of the models has not been possible because of the dearth of information concerning the microstructures that correspond with the swelling data. Whereas the lack of microstructure information is still an issue for historical swelling data, in the past 10–20 years data have been published on the evolution of the microstructure (point defect yields from collision cascades, cavity number densities, and dislocation densities/yield strengths) allowing certain gaps in information to be filled when considering historic swelling data. With reasonable estimates of key microstructure parameters, a standard rate theory model can be applied, and the model parameter space explored, in connection with historical swelling data. By using published data on: (i) yield strength as a function of dose and temperature (to establish an empirical expression for dislocation density evolution); (ii) cavity number densities as a function of temperature; and (iii) freely migrating defect (FMD) production as a function of primary knock-on atom (PKA) spectrum, the necessary parameter and microstructure inputs that were previously unknown can be used in model development. This paper describes a rate-theory model for void swelling of 316 stainless steel irradiated in the EBR-2 reactor as a function of irradiation temperature and neutron dose.

scholarly journals The Effect of Bulk Composition on Swelling and Radiation-Induced Segregation in Austenitic Alloys

2000 ◽  
Vol 650 ◽  
Author(s):  
T. R. Allen ◽  
J. I. Cole ◽  
N. L. Dietz ◽  
Y. Wang ◽  
G. S. Was ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Grain Boundary ◽  
Bulk Composition ◽  
High Energy ◽  
Lattice Parameter ◽  
304 Stainless Steel ◽  
Microstructural Development ◽  
Nickel Concentration ◽  
Void Swelling ◽  
Radiation Induced

ABSTRACTChanges in bulk composition are known to affect both radiation-induced segregation and microstructural development, including void swelling in austenitic stainless steel. In this work, three alloys (designations corresponding to wt%) have been studied: Fe-18Cr-8Ni alloy (bulk composition corresponding to 304 stainless steel), Fe-18Cr-40Ni (bulk composition corresponding to 330 stainless steel), and Fe-16Cr-13Ni (bulk composition corresponding to 316 stainless steel). Following irradiation with high-energy protons, the change in hardness and microstructure (void size distribution and grain boundary composition) due to irradiation was investigated. Increasing the bulk nickel concentration decreases void swelling, increases matrix hardening, and increases grain boundary chromium depletion and nickel enrichment. The analysis shows that decreases in lattice parameter and shear modulus due to radiation- induced segregation (RIS) correlate with decreased void swelling and a decreased susceptibility to irradiation assisted stress corrosion cracking (IASCC). Traditional thinking on IASCC assumed RIS was a contributing factor to cracking. It may, however, be that properly controlled RIS can be used to mitigating cracking.

Rate Theory for Dislocation Loops Evolution in AL-6XN Austenitic Stainless Steel under Proton Irradiation

2018 ◽  
Vol 913 ◽  
pp. 237-246 ◽  
Author(s):  
Yan Xia Yu ◽  
Li Ping Guo ◽  
Zheng Yu Shen ◽  
Yun Xiang Long ◽  
Zhong Cheng Zheng ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Supercritical Water ◽  
Proton Irradiation ◽  
Theory Model ◽  
Average Density ◽  
Rate Theory ◽  
Dislocation Loops ◽  
Average Size ◽  
Supercritical Water Cooled Reactor

The average size and density evolution of dislocation loops in AL-6XN austenitic stainless steel, a candidate fuel cladding material for supercritical water-cooled reactor, under proton irradiation were simulated through a rate theory model. The simulation results exhibit relatively good agreement with the experimental results at 563 K. The size and density of defect clusters are calculated under irradiation temperature between 550 K and 900 K and irradiation doses up to 15 dpa which satisfies the working condition in supercritical water-cooled reactor. The fast nucleation between self-interstitials happens at the initial stage of irradiation. The average size of dislocation loops increases while the average density of these loops reduces with the increasing temperature, and the average density approaches to a constant when irradiated at higher irradiation doses. The mechanism is discussed based on the variation of rate constants of defect reactions and the variation of the diffusion coefficients of interstitials and dislocation loops with dose and temperature.

A Phenomenological Model for the Effect of Nanocrystalline Microstructure on Irradiation-Induced Amorphization In U3Si

1994 ◽  
Vol 373 ◽  
Author(s):  
J. Rest
Keyword(s):  
Critical Temperature ◽  
Grain Boundaries ◽  
Ion Irradiation ◽  
Theory Model ◽  
Rate Theory ◽  
Two Phase ◽  
Thermal Crystallization ◽  
Acoustic Shock Wave ◽  
Radiation Induced ◽  
Nanocrystalline Microstructure

AbstractA rate theory model is formulated wherein amorphous clusters are formed by a damage event. These clusters are considered centers of expansion (CEs), or excess-free-volume zones. Simultaneously, centers of compression (CCs) are created in the material. The CCs are local regions of increased density that travel through the material as an elastic (e.g., acoustic) shock wave. The CEs can be annihilated upon contact with a sufficient number of CCs, to form either a crystallized region indistinguishable from the host material, or a region with a slight disorientation (recrystallized grain). Recrystallized grains grow by the accumulation of additional CCs.Preirradiation of U3Si above the critical temperature for amorphization results in the formation of nanometer-size grains. In addition, subsequent reirradiation of these samples in the same ion flux at temperatures below the critical temperature shows that the material has developed a resistance to radiation-induced amorphization (i.e., a higher dose is needed to amorphize preirradiated samples than those that have not been preirradiated). In the model, it is assumed that grain boundaries act as effective sinks for defects, and that enhanced defect annihilation is responsible for retarding amorphization below the critical temperature by, for example, preventing a buildup of vacancies adjacent to the grain boundaries. The calculations have been validated against data from ion-irradiation experiments with U3Si. For appropriate values of the activation energy of thermal crystallization, the model predicts the evolution of a two phase microstructure consisting of nanocrystalline grains and amorphous clusters.

Ab initio based rate theory model of radiation induced amorphization in β-SiC

2011 ◽  
Vol 414 (3) ◽  
pp. 431-439 ◽  
Author(s):  
Narasimhan Swaminathan ◽  
Dane Morgan ◽  
Izabela Szlufarska
Keyword(s):  
Ab Initio ◽  
Theory Model ◽  
Rate Theory ◽  
Radiation Induced

scholarly journals Impact of Coronavirus Outbreaks on Science and Society: Insights from Temporal Bibliometry of SARS and COVID-19

Entropy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. 626
Author(s):  
Ramya Gupta ◽  
Abhishek Prasad ◽  
Suresh Babu ◽  
Gitanjali Yadav
Keyword(s):  
Published Data ◽  
Science And Society ◽  
Time Dimension ◽  
Scientific Publications ◽  
The Past ◽  
Economic Trends ◽  
Global Events ◽  
One Year ◽  
Personal Devices ◽  
Share Information

A global event such as the COVID-19 crisis presents new, often unexpected responses that are fascinating to investigate from both scientific and social standpoints. Despite several documented similarities, the coronavirus pandemic is clearly distinct from the 1918 flu pandemic in terms of our exponentially increased, almost instantaneous ability to access/share information, offering an unprecedented opportunity to visualise rippling effects of global events across space and time. Personal devices provide “big data” on people’s movement, the environment and economic trends, while access to the unprecedented flurry in scientific publications and media posts provides a measure of the response of the educated world to the crisis. Most bibliometric (co-authorship, co-citation, or bibliographic coupling) analyses ignore the time dimension, but COVID-19 has made it possible to perform a detailed temporal investigation into the pandemic. Here, we report a comprehensive network analysis based on more than 20,000 published documents on viral epidemics, authored by over 75,000 individuals from 140 nations in the past one year of the crisis. Unlike the 1918 flu pandemic, access to published data over the past two decades enabled a comparison of publishing trends between the ongoing COVID-19 pandemic and those of the 2003 SARS epidemic to study changes in thematic foci and societal pressures dictating research over the course of a crisis.

Sign in / Sign up

Export Citation Format

Share Document