• Energy Research

Is it true that a nuclear technology approach to generate electric energy offers a clean, safe, reliable and affordable, i.e., sustainable option? In principle yes, however a technology impact on the environment strongly depends on the actual implementation bearing residual risks due to technical failures, human factors, or natural catastrophes. A full response is thus difficult and can be given first when the wicked multi-disciplinary issues get well formulated and “resolved”. These problems are lying at the interface between: the necessary R&D effort, the industrial deployment and the technology impact in view of the environmental sustainability including the management of produced hazardous waste. As such, this problem is clearly of multi-dimensional nature. This enormous complexity indicates that just a description of the problem might cause a dilemma. The paper proposes a novel holistic approach applying Multi-Criteria Decision Analysis to assess the potential of nuclear energy systems with respect to a sustainable performance. It shows how to establish a multi-level criteria structure tree and examines the trading-off techniques for scoring and ranking of options. The presented framework allows multi-criteria and multi-group treatment. The methodology can be applied to support any pre-decisional process launched in a country to find the best nuclear and/or non-nuclear option according to national preferences and priorities. The approach addresses major aspects of the environmental footprint of nuclear energy systems. As a case study, advanced nuclear fuel cycles are analyzed, which were previously investigated by the Nuclear Energy Agency (NEA/OECD) expert group WASTEMAN. Sustainability facets of waste management, resource utilization and economics are in focus.

This paper summarizes the experience gained in the application of multi-criteria decision making and uncertainty treatment methods to a comparative assessment of nuclear energy systems and related nuclear fuel cycles. These judgment measures provide a means for comprehensive evaluation according to different conflicting criteria, such as costs, benefits and risks, which are inevitably associated with the deployment of advanced technologies. Major findings and recommendations elaborated in international and national projects and studies are reviewed and discussed. A careful analysis is performed for multi-criteria comparative assessment of nuclear energy systems and nuclear fuel cycles on the basis of various evaluation and screening results. The purpose of this paper is to discuss the lessons learned, to share the identified solutions, and indicate promising future directions.

An unusual change of the contributed reactivity of uranium samples with 90% enrichment depending on the size was observed during experiments on the critical assembly of the large physical testing facility with a softened neutron spectrum: the reactivity became negative upon insertion of thin samples. The agreement between the calculations and experimental data in the description of this unusual change of reactivity was obtained by making changes in the radiative capture cross section of 235U and the factors of resonance self-screening in the group approximation and by taking account of the possible missed narrow resonances of 235U in the point representation description of the experiment.

A computational and experimental analysis is presented of a systematized and reconsidered series of experimental studies of the absolute fission rate of Pu, Np, Am, and Cm performed on the critical benches BFS-1, -2 in the period from 1990 to 2013. Twenty seven critical configurations are examined – models of the reactor core with different types of fuel and coolant. Previously obtained experimental values are re-examined according to more accurate methods of processing the results taking account of residual deformations of chambers and with the introduction of corrections for the efficiency of fragment detection (acts of fission in chambers). The computational models of the assemblies are supplemented by models for evaluating the ratio of the fission rates using non-analogical modeling algorithms. The matched set of experimental data and computational models can be used in diverse applied and fundamental problems.

The possibility of applying multicriterial and robust optimization methods as well as stochastic methods of determining the effect of uncertainties in the parameters of a system to structural optimization of nuclear power is discussed for the example of a hypothetical nuclear-power system consisting of thermal and fast reactors. It is shown that the optimal structures of nuclear power systems obtained by such methods are balanced in terms of conflicting criteria and technologically more diversified than those determined by single-criterion deterministic optimization. Cost-based innovative technologies, which can be adopted only by imposing additional external limitations in a single-criterion problem, appear in such structures. The examined methods make it possible to determine on a systematic basis the structures of nuclear power that are balanced in terms of a set of conflicting criteria, since factors having both positive and negative effects on the development of nuclear-power systems are included in the calculations, and to find economically efficient directions of structural changes in the system in order to improve stability and efficiency.

The work presents the approaches and software developed for multi-objective optimization of nuclear power structures: the modules for energy planning package MESSAGE intended for modeling purposes of developing nuclear power systems and multi-objective evaluation of its effectiveness and an integrated approach based on the method of system dynamics and parameter space investigation, allowing the problem of optimizing a nuclear power system structure in multi-objective formulation to be solved. Some results of implementation of these tools for multi-objective optimization of nuclear power structures are shown.

This article analyzes the present status, development trends, and problems in the ethics of nuclear technology in light of a possible revision of its conceptual foundations. First, to better recognize the current state of nuclear technology ethics and related problems, this article focuses on presenting a picture of the evolution of the concepts and recent achievements related to technoethics, based on the ethics of responsibility. The term 'ethics of nuclear technology' describes a multidisciplinary endeavor to examine the problems associated with nuclear technology through ethical frameworks and paradigms. Second, to identify the reasons for the intensification of efforts to develop ethics in relation to nuclear technology, this article presents an analysis of the recent situation and future prospects of nuclear technology deployment. This includes contradictions that have aggravated nuclear dilemmas and debates stimulated by the shortcomings of nuclear technology, as well as the need for the further development of a nuclear culture paradigm that is able to provide a conceptual framework to overcome nuclear challenges. Third, efforts in the field of nuclear technology ethics are presented as a short overview of particular examples, and the major findings regarding obstacles to the development of nuclear technology ethics are also summarized. Finally, a potential methodological course is proposed to overcome inaction in this field; the proposed course provides for the further development of nuclear technology ethics, assuming the axiological multidisciplinary problematization of the main concepts in nuclear engineering through the basic ethical paradigms: analytical, hermeneutical, and poststructuralist.

The paper proposes a multicriteria decision analysis (MCDA) framework for a comparative evaluation of nuclear waste management strategies taking into account different local perspectives (expert and stakeholder opinions). Of note, a novel approach is taken using a multiple-criteria formulation that is methodologically adapted to tackle various conflicting criteria and a large number of expert/stakeholder groups involved in the decision-making process. The purpose is to develop a framework and to show its application to qualitative comparison and ranking of options in a hypothetical case of three waste management alternatives: interim storage at and/or away from the reactor site for the next 100 years, interim decay storage followed in midterm by disposal in a national repository, and disposal in a multinational repository. Additionally, major aspects of a decision-making aid are identified and discussed in separate paper sections dedicated to application context, decision supporting process, in particular problem structuring, objective hierarchy, performance evaluation modeling, sensitivity/robustness analyses, and interpretation of results (practical impact). The aim of the paper is to demonstrate the application of the MCDA framework developed to a generic hypothetical case and indicate how MCDA could support a decision on nuclear waste management policies in a “small” newcomer country embarking on nuclear technology in the future.