Research

1931 KiB

Open AccessArticle

Innovative Nuclear Energy Systems: State-of-the Art Survey on Evaluation and Aggregation Judgment Measures Applied to Performance Comparison

by Vladimir Kuznetsov, Galina Fesenko, Aleksandra Schwenk-Ferrero, Andrei Andrianov and Ilya Kuptsov

Energies 2015, 8(5), 3679-3719; https://doi.org/10.3390/en8053679 - 30 Apr 2015

Cited by 17 | Viewed by 8162

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Advances in Nuclear Reactor and Fuel Cycle Technologies)

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471 KiB

Open AccessArticle

Radiological Impacts and Regulation of Rare Earth Elements in Non-Nuclear Energy Production

by Timothy Ault, Steven Krahn and Allen Croff

Energies 2015, 8(3), 2066-2081; https://doi.org/10.3390/en8032066 - 13 Mar 2015

Cited by 39 | Viewed by 6858

Abstract

Energy industries account for a significant portion of total rare earth usage, both in the US and worldwide. Rare earth minerals are frequently collocated with naturally occurring radioactive material, imparting an occupational radiological dose during recovery. This paper explores the extent to which [...] Read more.

Energy industries account for a significant portion of total rare earth usage, both in the US and worldwide. Rare earth minerals are frequently collocated with naturally occurring radioactive material, imparting an occupational radiological dose during recovery. This paper explores the extent to which rare earths are used by various non-nuclear energy industries and estimates the radiological dose which can be attributed to these industries on absolute and normalized scales. It was determined that typical rare earth mining results in an occupational collective dose of approximately 0.0061 person-mSv/t rare earth elements, amounting to a total of 330 person-mSv/year across all non-nuclear energy industries (about 60% of the annual collective dose from one pressurized water reactor operated in the US, although for rare earth mining the impact is spread out over many more workers). About half of the collective dose from non-nuclear energy production results from use of fuel cracking catalysts for oil refining, although given the extent of the oil industry, it is a small dose when normalized to the energy equivalent of the oil that is used annually. Another factor in energy industries’ reliance on rare earths is the complicated state of the regulation of naturally occurring radiological materials; correspondingly, this paper also explores regulatory and management implications. Full article

(This article belongs to the Special Issue Advances in Nuclear Reactor and Fuel Cycle Technologies)

327 KiB

Open AccessArticle

Impact of the Taxes on Used Nuclear Fuel on the Fuel Cycle Economics in Spain

by B. Yolanda Moratilla Soria, Rosario Ruiz-Sánchez, Mathilde Estadieu, Borja Belda-Sánchez, Cristina Cordón-Peralta, Paula Martín-Cañas, Laura Rodriguez-Penalonga, M. Del Mar Cledera-Castro, M. Ana Sáenz-Nuño and Carlos Morales-Polo

Energies 2015, 8(2), 1426-1439; https://doi.org/10.3390/en8021426 - 13 Feb 2015

Cited by 3 | Viewed by 6056

Abstract

In 2013, the Spanish government created two new taxes on used nuclear fuel. This article aims to present the results of an economic study carried out to compare the costs of long-term storage of used nuclear fuel –open cycle strategy–, with [...] Read more.

In 2013, the Spanish government created two new taxes on used nuclear fuel. This article aims to present the results of an economic study carried out to compare the costs of long-term storage of used nuclear fuel –open cycle strategy–, with the cost of the strategy of reprocessing and recycling used fuel– closed cycle strategy– taking into account the impact of the new taxes on the global cost of the fuel cycle. The results show that the costs of open-cycle and closed-cycle spent fuel management, evaluated in Spain after the introduction of the taxes, are sufficiently similar (within the bounds of uncertainty), that the choice between both is predicated on other than purely economic criteria. Full article

(This article belongs to the Special Issue Advances in Nuclear Reactor and Fuel Cycle Technologies)

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781 KiB

Open AccessArticle

Hybrid Statistical Testing for Nuclear Material Accounting Data and/or Process Monitoring Data in Nuclear Safeguards

by Tom Burr, Michael S. Hamada, Larry Ticknor and James Sprinkle

Energies 2015, 8(1), 501-528; https://doi.org/10.3390/en8010501 - 13 Jan 2015

Cited by 5 | Viewed by 5984

Abstract

The aim of nuclear safeguards is to ensure that special nuclear material is used for peaceful purposes. Historically, nuclear material accounting (NMA) has provided the quantitative basis for monitoring for nuclear material loss or diversion, and process monitoring (PM) data is collected by [...] Read more.

The aim of nuclear safeguards is to ensure that special nuclear material is used for peaceful purposes. Historically, nuclear material accounting (NMA) has provided the quantitative basis for monitoring for nuclear material loss or diversion, and process monitoring (PM) data is collected by the operator to monitor the process. PM data typically support NMA in various ways, often by providing a basis to estimate some of the in-process nuclear material inventory. We develop options for combining PM residuals and NMA residuals (residual = measurement − prediction), using a hybrid of period-driven and data-driven hypothesis testing. The modified statistical tests can be used on time series of NMA residuals (the NMA residual is the familiar material balance), or on a combination of PM and NMA residuals. The PM residuals can be generated on a fixed time schedule or as events occur. Full article

(This article belongs to the Special Issue Advances in Nuclear Reactor and Fuel Cycle Technologies)

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3735 KiB

Open AccessArticle

Atmospheric Dispersion of Radioactivity from Nuclear Power Plant Accidents: Global Assessment and Case Study for the Eastern Mediterranean and Middle East

by Theodoros Christoudias, Yiannis Proestos and Jos Lelieveld

Energies 2014, 7(12), 8338-8354; https://doi.org/10.3390/en7128338 - 12 Dec 2014

Cited by 7 | Viewed by 15342

Abstract

We estimate the contamination risks from the atmospheric dispersion of radionuclides released by severe nuclear power plant accidents using the ECHAM/Modular Earth Submodel System (MESSy) atmospheric chemistry (EMAC) atmospheric chemistry-general circulation model at high resolution (50 km). We present an overview of global [...] Read more.

We estimate the contamination risks from the atmospheric dispersion of radionuclides released by severe nuclear power plant accidents using the ECHAM/Modular Earth Submodel System (MESSy) atmospheric chemistry (EMAC) atmospheric chemistry-general circulation model at high resolution (50 km). We present an overview of global risks and also a case study of nuclear power plants that are currently under construction, planned and proposed in the Eastern Mediterranean and Middle East, a region prone to earthquakes. We implemented continuous emissions from each location, making the simplifying assumption that all potential accidents release the same amount of radioactivity. We simulated atmospheric transport and decay, focusing on ¹³⁷Cs and ¹³¹I as proxies for particulate and gaseous radionuclides, respectively. We present risk maps for potential surface layer concentrations, deposition and doses to humans from the inhalation exposure of ¹³¹I. The estimated risks exhibit seasonal variability, with the highest surface level concentrations of gaseous radionuclides in the Northern Hemisphere during winter. Full article

(This article belongs to the Special Issue Advances in Nuclear Reactor and Fuel Cycle Technologies)

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1546 KiB

Open AccessArticle

The Application of Discontinuous Galerkin Methods in Conjugate Heat Transfer Simulations of Gas Turbines

by Zeng-Rong Hao, Chun-Wei Gu and Xiao-Dong Ren

Energies 2014, 7(12), 7857-7877; https://doi.org/10.3390/en7127857 - 26 Nov 2014

Cited by 20 | Viewed by 7059

Abstract

The performance of modern heavy-duty gas turbines is greatly determined by the accurate numerical predictions of thermal loading on the hot-end components. The purpose of this paper is: (1) to present an approach applying a novel numerical technique—the discontinuous Galerkin (DG) method—to conjugate [...] Read more.

The performance of modern heavy-duty gas turbines is greatly determined by the accurate numerical predictions of thermal loading on the hot-end components. The purpose of this paper is: (1) to present an approach applying a novel numerical technique—the discontinuous Galerkin (DG) method—to conjugate heat transfer (CHT) simulations, develop the engineering-oriented numerical platform, and validate the feasibility of the methodology and tool preliminarily; and (2) to utilize the constructed platform to investigate the aerothermodynamic features of a typical transonic turbine vane with convection cooling. Fluid dynamic and solid heat conductive equations are discretized into explicit DG formulations. A centroid-expanded Taylor basis is adopted for various types of elements. The Bassi-Rebay method is used in the computation of gradients. A coupled strategy based on a data exchange process via numerical flux on interface quadrature points is simply devised. Additionally, various turbulence Reynolds-Averaged-Navier-Stokes (RANS) models and the local-variable-based transition model γ-Re_θ are assimilated into the integral framework, combining sophisticated modelling with the innovative algorithm. Numerical tests exhibit good consistency between computational and analytical or experimental results, demonstrating that the presented approach and tool can handle well general CHT simulations. Application and analysis in the turbine vane, focusing on features around where there in cluster exist shock, separation and transition, illustrate the effects of Bradshaw’s shear stress limitation and separation-induced-transition modelling. The general overestimation of heat transfer intensity behind shock is conjectured to be associated with compressibility effects on transition modeling. This work presents an unconventional formulation in CHT problems and achieves its engineering applications in gas turbines. Full article

(This article belongs to the Special Issue Advances in Nuclear Reactor and Fuel Cycle Technologies)

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857 KiB

Open AccessArticle

A Mine-Based Uranium Market Clearing Model

by Aris Auzans, Erich A. Schneider, Robert Flanagan and Alan H. Tkaczyk

Energies 2014, 7(11), 7673-7693; https://doi.org/10.3390/en7117673 - 19 Nov 2014

Cited by 5 | Viewed by 6183

Abstract

Economic analysis and market simulation tools are used to evaluate uranium (U) supply shocks, sale or purchase of uranium stockpiles, or market effects of new uranium mines or enrichment technologies. This work expands on an existing U market model that couples the market [...] Read more.

Economic analysis and market simulation tools are used to evaluate uranium (U) supply shocks, sale or purchase of uranium stockpiles, or market effects of new uranium mines or enrichment technologies. This work expands on an existing U market model that couples the market for primary U from uranium mines with those of secondary uranium, e.g., depleted uranium (DU) upgrading or highly enriched uranium (HEU) down blending, and enrichment services. This model accounts for the interdependence between the primary U supply on the U market price, the economic characteristics of each individual U mine, sources of secondary supply, and the U enrichment market. This work defines a procedure for developing an aggregate supply curve for primary uranium from marginal cost curves for individual firms (Uranium mines). Under this model, market conditions drive individual mines’ startup and short- and long-term shutdown decisions. It is applied to the uranium industry for the period 2010–2030 in order to illustrate the evolution of the front end markets under conditions of moderate growth in demand for nuclear fuel. The approach is applicable not only to uranium mines but also other facilities and reactors within the nuclear economy that may be modeled as independent, decision-making entities inside a nuclear fuel cycle simulator. Full article

(This article belongs to the Special Issue Advances in Nuclear Reactor and Fuel Cycle Technologies)

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724 KiB

Open AccessArticle

Saturated Adaptive Output-Feedback Power-Level Control for Modular High Temperature Gas-Cooled Reactors

by Zhe Dong

Energies 2014, 7(11), 7620-7639; https://doi.org/10.3390/en7117620 - 19 Nov 2014

Cited by 5 | Viewed by 6648

Abstract

Small modular reactors (SMRs) are those nuclear fission reactors with electrical output powers of less than 300 MW_e. Due to its inherent safety features, the modular high temperature gas-cooled reactor (MHTGR) has been seen as one of the best candidates for [...] Read more.

Small modular reactors (SMRs) are those nuclear fission reactors with electrical output powers of less than 300 MW_e. Due to its inherent safety features, the modular high temperature gas-cooled reactor (MHTGR) has been seen as one of the best candidates for building SMR-based nuclear plants with high safety-level and economical competitive power. Power-level control is crucial in providing grid-appropriation for all types of SMRs. Usually, there exists nonlinearity, parameter uncertainty and control input saturation in the SMR-based plant dynamics. Motivated by this, a novel saturated adaptive output-feedback power-level control of the MHTGR is proposed in this paper. This newly-built control law has the virtues of having relatively neat form, of being strong adaptive to parameter uncertainty and of being able to compensate control input saturation, which are given by constructing Lyapunov functions based upon the shifted-ectropies of neutron kinetics and reactor thermal-hydraulics, giving an online tuning algorithm for the controller parameters and proposing a control input saturation compensator respectively. It is proved theoretically that input-to-state stability (ISS) can be guaranteed for the corresponding closed-loop system. In order to verify the theoretical results, this new control strategy is then applied to the large-range power maneuvering control for the MHTGR of the HTR-PM plant. Numerical simulation results show not only the relationship between regulating performance and control input saturation bound but also the feasibility of applying this saturated adaptive control law practically. Full article

(This article belongs to the Special Issue Advances in Nuclear Reactor and Fuel Cycle Technologies)

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1675 KiB

Open AccessArticle

Optimizing the Design of Small Fast Spectrum Battery-Type Nuclear Reactors

by Staffan Qvist

Energies 2014, 7(8), 4910-4937; https://doi.org/10.3390/en7084910 - 31 Jul 2014

Cited by 11 | Viewed by 7666

Abstract

This study is focused on defining and optimizing the design parameters of inherently safe “battery” type sodium-cooled metallic-fueled nuclear reactor cores that operate on a single stationary fuel loading at full power for 30 years. A total of 29 core designs were developed [...] Read more.

This study is focused on defining and optimizing the design parameters of inherently safe “battery” type sodium-cooled metallic-fueled nuclear reactor cores that operate on a single stationary fuel loading at full power for 30 years. A total of 29 core designs were developed with varying power and flow conditions, including detailed thermal-hydraulic, structural-mechanical and neutronic analysis. Given set constraints for irradiation damage, primary cycle pressure drop and inherent safety considerations, the attainable power range and performance characteristics of the systems are defined. The optimum power level for a core with a coolant pressure drop limit of 100 kPa and an irradiation damage limit of 200 DPA (displacements per atom) is found to be 100 MWt/40 MWe. Raising the power level of an optimized core gives significantly higher attainable power densities and burnup, but severely decreases safety margins and increases the irradiation damage. A fully optimized inherently safe battery-type fast reactor core with an active height and diameter of 150 cm (2.6 m³), a pressure drop limit of 100 kPa and an irradiation damage limit of 300 DPA can be designed to operate at 150 MWt/60 MWe for 30 years, reaching an average discharge burnup of 100 MWd/kg-actinide. Full article

(This article belongs to the Special Issue Advances in Nuclear Reactor and Fuel Cycle Technologies)

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