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1 – 10 of 81Branko Kontic, Matjaz Ravnik, Peter Stegnar and Burton C. Kross
To clarify uncertainty in predictions of the quantity, radionuclide inventory and activity of waste from the Krsko nuclear power plant, and to illuminate its role in related…
Abstract
To clarify uncertainty in predictions of the quantity, radionuclide inventory and activity of waste from the Krsko nuclear power plant, and to illuminate its role in related policy‐making, we made a scenario analysis in order to find out the variation in waste characteristics if the plant operates five years shorter or longer than anticipated, or if it uses fuel of a higher enrichment (levels between 3 per cent and 5 per cent of U‐235). We used ORIGEN2 computer code for calculations connected to spent fuel, and developed a code for calculating low‐ and intermediate‐level waste. We present and interpret our results using language which can be understood by decision makers and the general public. We believe that the clarification of the issues gained through our analysis will contribute to more informed decision making and be effective in building confidence among professionals, the public and politicians in the process of identifying the most appropriate waste management options.
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Peter Brennecke and Ingo Beckmerhagen
In Germany radioactive waste with negligible heat generation, i.e. LLWand ILW, is planned to be disposed of in the Konrad repository. Theconstruction and operation of this…
Abstract
In Germany radioactive waste with negligible heat generation, i.e. LLW and ILW, is planned to be disposed of in the Konrad repository. The construction and operation of this disposal mine necessitates quality assurance (QA) and quality control (QC) programmes focusing on the above‐ground and underground facilities as well as on the waste packages to be disposed of. The QA organization provides a division of this facility into three areas with different requirements on the measures to be taken. For classification of systems and companies the results of the safety assessment, in particular of the incident analysis, are used. The waste package QC, i.e. the fulfillment of waste acceptance requirements, is either to be performed by checking the waste producer’s documentation and carrying out random tests or by qualifying and subsequently inspecting the waste conditioning process.
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Gang Peng, Zhiming Gao, Wenjing Yan and Xinlong Feng
This paper aims to consider numerical simulation for radionuclide transport calculations in geological radioactive waste repository.
Abstract
Purpose
This paper aims to consider numerical simulation for radionuclide transport calculations in geological radioactive waste repository.
Design/methodology/approach
The nonlinear two-point flux approximation is used to discretize the diffusion flux and has a fixed stencil. The cell-vertex unknowns are applied to define the auxiliary unknowns and can be interpolated by the cell-centered unknowns. The approximation of convection flux is based on the second-order upwind method with a slope limiter.
Findings
Numerical results illustrate that the positivity-preserving is satisfied in solving this convection-diffusion system and has a second-order convergence rate on the distorted meshes.
Originality/value
A new positivity-preserving nonlinear finite volume scheme is proposed to simulate the far-field model used in the geological radioactive waste repository. Numerical results illustrate that the positivity-preserving is satisfied in solving this convection-diffusion system and has a second-order convergence rate on the distorted meshes.
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The need for long-term stewardship for hazards is widespread and increasing. Many of the largest and most complex sites requiring stewardship are within the U.S. Department of…
Abstract
The need for long-term stewardship for hazards is widespread and increasing. Many of the largest and most complex sites requiring stewardship are within the U.S. Department of Energy's nuclear weapons complex, though many “brownfields” and Superfund sites in the private sector have similar needs for long-term care. High cleanup costs and difficult-to-resolve technical challenges are the main reasons why such sites are not being cleaned up to support unrestricted use. EPA policy changes are now redirecting cleanup efforts toward waste isolation and containment-in-place rather than waste removal. This shift is not being matched by a corresponding shift in the conceptual and operational approach to remediation planning. The process logic of cleanup continues to be “single-pass” and linear, via sequential planning and implementation stages that aim to declare sites “cleaned up and closed” once the sought-after degree of waste isolation from the biotic environment is achieved. Instead an iterative and nonlinear process logic is required – one that directs cleanup toward the needs of effective stewardship of the remaining residual contamination rather than toward regulatory standards that support the selected future land use for the site. This redirection of cleanup logic shifts the focus in remediation planning to vulnerabilities and uncertainties associated with long-term stewardship rather than the degree of isolation of wastes from human populations and the environment achieved. Such a shift is needed in recognition that situations of restricted human use of still-contaminated sites are being created that remain vulnerable to failure given the length of time over which stewardship is required.
I.A. Beckmerhagen, H.P. Berg, S.V. Karapetrovic and W.O. Willborn
Integration of function‐specific management systems in organizations is rapidly becoming a topic of interest for managers and auditors alike. This is mainly due to the…
Abstract
Integration of function‐specific management systems in organizations is rapidly becoming a topic of interest for managers and auditors alike. This is mainly due to the proliferation of management system standards that foster compliance with the stated criteria for quality, environmental, occupational health and safety, social responsibility and other different aspects of performance. While most of the available literature on this topic focuses on the integration of standards, there is comparatively little information on how to actually build an integrated system internally. This paper hypothesizes that audits can provide an excellent basis for these integration efforts, discussing the prerequisites, strategies and resources necessary for an effective audit in support of integrated management systems. The paper also describes how audits are used to improve a combined quality and safety management system in a German nuclear facility.
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Many public issues, such as environmental actions, involve a large number of diverse stakeholders such as governments, corporations, organizations (e.g. NGOs), and concerned…
Abstract
Many public issues, such as environmental actions, involve a large number of diverse stakeholders such as governments, corporations, organizations (e.g. NGOs), and concerned citizens. Discussions frequently become contentious as the stakeholders defend their potentially conflicting goals with various assumptions, views, and expert testimony. These issues also tend to involve a range of fields. For example, the disposition of nuclear waste includes issues of economics, science, engineering, politics, and intergenerational justice, each with large uncertainties due to dependences on indirect estimations and the long time periods involved. At the same time that these complex issues might increase in number, due to applications of new technologies, tools are being developed on the Internet to enable flexible learning, visualization, collaborative conferencing, distributed computing, and meaning‐based (semantic) context. These tools might enable improved techniques for debating and discussing these complex issues. A technique that might facilitate orderly discussion of various arguments would include explicit recording and visualization of the evidence, its assumptions and uncertainties, their relationships in constructing the overall argument, and the ways the evidence needs to be generalized to support the argument. A simple argument visualization approach is explored based on a combination of an argument logic framework and techniques for fusing generalized data that are similar to kriging in spatial analysis. This approach is then applied to a recently contested risk analysis of nuclear waste disposition that was debated in a peer‐reviewed journal, involving concerns about uses of data, complex computational models, uncertainty analysis, and expert judgment. The need for wider understanding of such complex issues might be addressed by a convergence of techniques to facilitate greater understanding and the advanced Internet technologies to lower barriers to their adoption.
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J.R. Weatherby, D.E. Munson and J.G. Argüello
Describes a set of numerical techniques which implement the rate‐dependent multi‐mechanism deformation (M‐D) constitutive model for rock salt in a finite element code for use in…
Abstract
Describes a set of numerical techniques which implement the rate‐dependent multi‐mechanism deformation (M‐D) constitutive model for rock salt in a finite element code for use in three‐dimensional, finite strain simulations of creep closure in deeply buried salt excavations. Presents essential details of the numerical implementation. The constitutive model is exercised in a three‐dimensional closure simulation of a large underground field experiment. Compares results from the simulation against actual closure measurements taken from the experiment.
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Christina H. Drew, Michael Kern, Todd Martin, Max S. Power and Elaine M. Faustman
Openness is critical to long-term cleanup and stewardship of former nuclear weapons manufacturing facilities. Openness is especially challenging in such facilities because a…
Abstract
Openness is critical to long-term cleanup and stewardship of former nuclear weapons manufacturing facilities. Openness is especially challenging in such facilities because a culture of secrecy has dominated them since the earliest days of nuclear weapons development. This paper describes a multi-year effort at the Hanford Site called the Hanford Openness Workshops. The Workshops were convened to address and resolve issues impeding the availability and understanding of information important to public health, the environment, and decision–making. Lessons from the workshops can improve dialogue about nuclear waste cleanup and long-term stewardship among regulators, decision makers, stakeholders, and Tribes.
Valentin Bertsch, Martin Treitz, Jutta Geldermann and Otto Rentz
Emergency situations may differ in many ways but they share some common characteristics, such as the sudden onset and the need to transparently evaluate various usually…
Abstract
Purpose
Emergency situations may differ in many ways but they share some common characteristics, such as the sudden onset and the need to transparently evaluate various usually conflicting objectives. In nuclear power generation, however, emergency situations constitute a special challenge. The focus of this paper is to highlight the role of multi‐criteria decision analysis (MCDA) in nuclear emergency and recovery management on the basis of a hypothetical case study.
Design/methodology/approach
Multi‐attribute value theory as one field of research within MCDA is introduced. Special emphasis is placed on the modelling of the decision makers' preferences which is a crucial part in any multi‐criteria analysis. A central aim is to facilitate the preference elicitation in group decision processes.
Findings
The management of emergency situations in nuclear power generation necessitates the consideration of technical, economic, environmental, socio‐psychological and political aspects. Furthermore, various stakeholder and expert groups with diverse background knowledge and different views, responsibilities and interests are involved in such a decision‐making process. MCDA can help to take into account various incommensurable aspects and the subjective preferences of the decision makers and thus contribute to transparency and traceability of decision‐making processes. Since the preference parameters are inherently afflicted with uncertainties, thorough sensitivity analyses are important to visualise the impact of the uncertainties in an understandable way.
Originality/value
A new approach to sensitivity analysis is proposed, allowing one to comprehensibly visualise and communicate the impact of the uncertainties associated with the subjective preference parameters on the results of the decision analysis.
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This paper gives a bibliographical review of the finite element methods (FEMs) applied to the analysis of ceramics and glass materials. The bibliography at the end of the paper…
Abstract
This paper gives a bibliographical review of the finite element methods (FEMs) applied to the analysis of ceramics and glass materials. The bibliography at the end of the paper contains references to papers, conference proceedings and theses/dissertations on the subject that were published between 1977‐1998. The following topics are included: ceramics – material and mechanical properties in general, ceramic coatings and joining problems, ceramic composites, ferrites, piezoceramics, ceramic tools and machining, material processing simulations, fracture mechanics and damage, applications of ceramic/composites in engineering; glass – material and mechanical properties in general, glass fiber composites, material processing simulations, fracture mechanics and damage, and applications of glasses in engineering.
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