Modelling the Effects of Evolving Redox Conditions on the Corrosion of Copper Containers

1993 ◽  
Vol 333 ◽  
Author(s):  
F. King ◽  
D. M. LeNeveu ◽  
D. J. Jobe
Keyword(s):  
Nuclear Fuel ◽  
Waste Disposal ◽  
Corrosion Behaviour ◽  
Redox Conditions ◽  
Uniform Corrosion ◽  
Corrosive Environment ◽  
Change Over Time ◽  
Nuclear Fuel Waste ◽  
Over Time

ABSTRACTThe corrosive environment around the containers in a Canadian nuclear fuel waste disposal vault will change over time from “warm and oxidizing” to “cool and anoxic”. As the conditions change, so too will the corrosion behaviour of the containers. For copper containers, uniform corrosion and, possibly, pitting will occur during the initial aggressive phase, to be replaced by slow uniform corrosion during the long-term anoxic period.The corrosion behaviour of copper has been studied over a range of conditions representing all phases in the evolution of the vault environment. The results of these studies are summarized and used to illustrate how a model can be developed to predict the corrosion behaviour and container lifetimes over long periods of time. Lifetimes in excess of 106 a are predicted for 25-mm-thick. copper containers under Canadian disposal conditions.

A Numerical Model for the Corrosion of Copper Nuclear Fuel Waste Containers

1995 ◽  
Vol 412 ◽  
Author(s):  
F. King ◽  
M. Kolář
Keyword(s):  
Nuclear Fuel ◽  
Corrosion Potential ◽  
Corrosion Behaviour ◽  
Temporal Variations ◽  
Localized Corrosion ◽  
Uniform Corrosion ◽  
Adsorbed Species ◽  
Maximum Period ◽  
Nuclear Fuel Waste

AbstractA model is presented for the prediction of the long-term corrosion behaviour of Cu nuclear fuel waste containers. The model is based on a kinetic description of the processes involved in the uniform corrosion of Cu in a conceptual Canadian disposal vault. The 1-dimensional, multilayer model accounts for mass-transport, electrochemical and chemical processes and predicts the spatial and temporal variations of the concentrations of various dissolved, precipitated and adsorbed species, as well as the time dependence of the corrosion rate and the corrosion potential (ECORR). The variation of [O2], [Cu(II)] and ECORR with time can also be used to predict the maximum period over which localized corrosion processes, such as pitting or stress corrosion, may occur. Predictions from the model suggest that 25-mm-thick Cu containers will not fail due to uniform corrosion or pitting in periods <106 a.

Gender, mobility and contact

2021 ◽  
Vol 7 (2) ◽  
pp. 142-167
Author(s):  
Catherine E. Travis ◽  
Inas Ghina
Keyword(s):  
Older Women ◽  
High Mobility ◽  
Spontaneous Speech ◽  
Social Changes ◽  
Change Over Time ◽  
Aceh Province ◽  
Rural Variety ◽  
The Impact ◽  
Over Time

Abstract We examine variation in a rural variety of Acehnese spoken in Aceh Province, to better understand the impact of long-term contact with Indonesian and increasing urbanization. The Great Aceh variety is characterized by variable realization of word-final (t) as a dental vs. glottal stop. Analyses of over 2,000 tokens of this variable from a corpus of spontaneous speech from 35 speakers indicate that the variability is relatively stable among men, and among women of high mobility, measured in terms of education, occupation, and time spent outside Great Aceh. Women with low mobility produce the lowest rates of [t̪], and in this group we observe a higher rate of [t̪] by younger than older women, suggesting change over time. We thus find both stability – among those who have long enjoyed high levels of mobility – and change – among those most affected by recent social changes, namely low-mobility women.

Perspectives on the Review of AECL's Proposal for Disposing of Canada's Nuclear Fuel Waste

1997 ◽  
Vol 506 ◽  
Author(s):  
K.W. Dormuth ◽  
P.A. Gillespie ◽  
S.H. Whitaker
Keyword(s):  
Nuclear Fuel ◽  
Environmental Assessment ◽  
Geological Disposal ◽  
The Public ◽  
Public Hearings ◽  
Points Of View ◽  
Nuclear Fuel Waste ◽  
Term Management

ABSTRACTA federal Environmental Assessment Panel has completed public hearings on the proposed concept for geological disposal of Canada's nuclear fuel waste. The Panel will make recommendations to assist the governments of Canada and Ontario in reaching decisions on the acceptability of the proposed concept and on the steps that must be taken to ensure the safe long-term management of nuclear fuel waste in Canada. It is instructive to review the background to the public hearings, to consider the issues that have been important in the public review, and to reflect on the opposing points of view presented at the hearings.

Raptor Prey Remains

2020 ◽  
Author(s):  
Ed Drewitt
Keyword(s):  
Feeding Ecology ◽  
Prey Species ◽  
Local Level ◽  
Body Parts ◽  
Change Over Time ◽  
The Common ◽  
Prey Remains ◽  
Over Time ◽  
Prey Populations

Are you curious about the remains of an animal you have found? This compilation of the most likely found body parts of animals eaten by raptors will help you identify your discovery. Including over 100 species of bird and mammal prey of raptors such as sparrowhawks, peregrines and hen harriers, this photographic guide highlights the common feathers, fur and other body parts found at raptor nests, roosts, plucking posts and other opportunistic spots. Discovering what raptors eat is an important part of confirming their feeding ecology and how this might change over time, vary on a local level or in response to changing prey populations, as well as dispelling myths and assumptions about what certain raptor species eat. Diet studies are vital for the conservation of raptor species; the more we know about what they need for survival the more we can predict and plan long-term for the protection and survival of raptors that may be vulnerable and in decline. This is the first book to show in detail the actual parts of a bird, mammal or other animal that you are likely to find in a garden, woodland or beneath a raptor roost. As more people take an interest in raptors and watch species such as peregrines via webcams and through watch groups, there is greater opportunity for finding prey remains. This book provides the first and most important step in identifying a prey species.

Materials Research for the Canadian Nuclear Fuel Waste Management Program

1981 ◽  
Vol 6 ◽  
Author(s):  
Donald J. Cameron
Keyword(s):  
Nuclear Fuel ◽  
Waste Disposal ◽  
Hard Rock ◽  
Technology Development ◽  
Management Program ◽  
Materials Research ◽  
Backfill Materials ◽  
Nuclear Fuel Waste ◽  
Irradiated Fuel ◽  
Selection Of

ABSTRACTNuclear fuel waste disposal research in Canada is concentrating on hard-rock disposal. The research programs concerned with the man-made components of the disposal system are reviewed. Irradiated fuel and solidified reprocessing wastes are both being researched, as are durable containers, and buffer and backfill materials. This review concentrates mainly on the more scientific aspects of the research, which contribute to the selection of preferred options for the various components of the system, and which support directly or indirectly the safety analysis of the disposal concept. Some technology development is included in the program now, and this is expected to expand as confidence in the acceptability of the disposal concept grows.

A systems life cycle approach to managing the radiology profession: an Australian perspective

2015 ◽  
Vol 39 (2) ◽  
pp. 228 ◽  
Author(s):  
Seyedamir Tavakoli Taba ◽  
Simon Reay Atkinson ◽  
Sarah Lewis ◽  
Kon Shing Kenneth Chung ◽  
Liaquat Hossain
Keyword(s):  
System Dynamics ◽  
Supply And Demand ◽  
Workforce Planning ◽  
Life Cycle Approach ◽  
Intake Rate ◽  
Sustainable Change ◽  
Change Over Time ◽  
Prescriptive Model ◽  
Over Time

Objective Although the medical system has expanded considerably over the past two decades in almost all countries, so too has the demand for health care. The radiology specialisation may be an early system indicator, being especially sensitive to changes in supply and demand in both rural and urban environments. The question is whether the new policies of increasing the number of radiologists can be a proper long-term solution for the imbalance of workforce supply and demand or not. Methods Using system dynamics modelling, we present our integrated descriptive models for the supply and demand of Australian radiologists to find the actual gap. Followed by this, we pose a prescriptive model for the supply in order to lessen the identified imbalance between supply and demand. Our system dynamics models compare the demand and supply of Australian radiologists over 40 years between 2010 and 2050. Results The descriptive model shows that even if the radiology training program grows at a higher rate than the medical training growth rate and its own historical growth, the system will never be able to meet demand. The prescriptive model also indicates that although changing some influential factors (e.g the intake rate) reduces the level of imbalance, the system will still stay unstable during the study period. Conclusion We posit that Australia may need to design a new system of radiology provision to meet future demands for high-quality medical radiation services. We also suggest some strategies, such as greater development of radiographers’ role, are critical for enabling sustainable change over time. What is known about the topic? Long-term workforce planning for medical services at the national level has been very challenging for policy makers of the 21st century. The current demographic imbalance in the supply and demand of the Australian radiologist workforce makes it difficult to plan the effects of extra inflow of radiology students over time. What does this paper add? This paper discovers the current situation facing the Australian Radiology profession and identifies all the factors that influence the long-term matching of radiologist workforce supply and demand. This Australian case study adds to the current literature of medical workforce planning and its challenges. Moreover, this paper answers how the problem of workforce imbalance can be solved through a sustainable change over time. What are the implications for practitioners? Conventional responses in Australia and many developed countries in response to radiological services demand have been to increase the number of radiologists. However, our models and analyses show that this is not an all-inclusive long-term solution: merely increasing the number of radiologists will not result in a balance between supply and demand.

The surface water model for assessing Canada's nuclear fuel waste disposal concept

1993 ◽  
Vol 13 (2) ◽  
pp. 153-170 ◽  
Author(s):  
G.A. Bird ◽  
M. Stephenson ◽  
R.J. Cornett
Keyword(s):  
Surface Water ◽  
Nuclear Fuel ◽  
Waste Disposal ◽  
Water Model ◽  
Nuclear Fuel Waste
Sign in / Sign up

Export Citation Format

Share Document