Cycle Facilities Research Articles

IMPLEMENTATION OF IAEA SAFEGUARDS IN A STATE WITH AN IMPORTED FAST REACTOR AND A CLOSED NUCLEAR FUEL CYCLE

The implementation of the IAEA safeguards in the non-nuclear weapon state party to the NPT (Non-Proliferation Treaty) that has imported the fast-neutron reactor with nuclear fuel cycle facilities is considered. The features of fast reactors that should be taken into account when preparing them for export together with CNFC technologies considering the implementation of IAEA safeguards in the importing state, are noted. These include high mass fraction of plutonium in fresh fuel loads and handling of a large amounts of fissile materials in the technological cycles of reprocessing spent nuclear fuel. It is concluded that it is possible to implement the effective IAEA safeguards in the state importing such reactor and nuclear fuel cycle facilities considering their physical and design features and innovative technologies, including those used in the IAEA safeguards implementation.

Export prospects of fast reactors desined in Russia with closed nuclear fuel cycle facilities

The inevitability of switching to carbon-free energy to withstand the climate change is no longer disputed by anyone today. There is no alternative to this, and the scientific community is forming an appropriate understanding of the need for the development of nuclear energy as carbon free energy source. Solutions are already being discussed at the level of the President and the Government of Russia. In this regard, the article shows that such a solution is possible only based on a new technological platform – two-component nuclear power with the development of technologies of fast reactors with a closed fuel cycle. At the same time the prevailing view in the public opinion of Russia, and not only in it, is that climate change problem can be solved only at the expense of solar and wind energy. This attitude needs to be changed, because without the understanding and support of society, it is impossible to achieve a wide spread of fast reactors with closed fuel cycle technologies. It is concluded that in order to promote a new technological platform in commercial energy and ensure the export prospects of fast reactors of Russian design with closed nuclear fuel cycle facilities, it is necessary to attract representatives of business circles and large energy businesses to the number of supporters of such development by demonstrating the profitability of solutions in the medium and long term, implemented in the case of the use of Russian technologies of fast reactors with the closure of the nuclear fuel cycle.

Comparative Observational Assessment of Cyclists’ Interactions on Urban Streets with On-Street and Sidewalk Bike Lanes

The competition for urban space and the debate about where people can and should ride their bicycles began not long after this new form of mobility was introduced to the public. For two centuries, we have debated and eventually investigated whether bike lanes belong on the sidewalk or if they should be on the street alongside the vehicular roadway. Existing research has provided evidence of preferences for bike lane alignment based on perceived safety or comfort as well as objective measures of comparative safety based on available crash and hospital data. Much of the existing research has been driven by deductive assumptions or is limited by the lack of data describing near-miss events and the subtle everyday interactions cyclists experience when using different types of cycle facilities. To help us understand better what role everyday interactions play in the relative functionality of sidewalk and on-street bike lanes, an observational study was conducted using a new qualitative–quantitative grounded theory-driven method for identifying and interpreting the outcome of cyclists’ interactions. Using data gathered from 2,583 interactions observed at four case study street segments in Munich, Germany, four outcomes were identified: no reaction; adjusting or yielding; lane exiting; or multiple reactions. Based on inferential analyses of these outcomes, this paper presents an assessment of the safety, directness, and access afforded or hindered by the spatial conditions of observed interactions. The results of this assessment revealed a trade-off between frequent, but minor interactions in sidewalk bike lanes and infrequent, but less safe interactions in on-street bike lanes.

Development of a Mathematical Model for Solid Fuel Gasification and Its Sensitivity Analysis

Within the framework of this study, a brief review of the gasification technology was carried out, the best types of blowing agents and gasification methods used in terms of efficiency and environmental safety were identified, and a mathematical model of a steam–oxygen gasifier was developed in the MS Excel software package. The authors paid special attention to the consideration of the effect of changing the input parameters of the syngas, such as the temperature and relative mass flow rate of steam and oxygen, on the heat of the combustion of the produced syngas. As a result of the research, methods for increasing the heat of the combustion of the syngas and the conditions for using the described methods were formulated. The work also revealed the optimal ratios of the blowing agents and solid fuel supplied for gasification and presented the output parameters of the produced generator gas, including the heat of combustion of the gas, the gas temperature, and the gasification efficiency. Computer simulation models of the gasifier and gasification process were the basis for the analysis of a combined cycle (CC) facility with an integrated solid fuel gasifier. The heat flow thermodynamic analysis shows that the gasification steam bleeding from the turbine is the best solution for the improvement of cycle efficiency.

Терроризм и оружие массового уничтожения – опасный симбиоз

Against the backdrop of a sharp aggravation of the international situation, the growth of fundamental contradictions between Russia and Western countries, and the growing disunity of the international community, the terrorist threat is increasing. Its most dangerous manifestations are the attempts already made by terrorists to use elements of weapons of mass destruction (WMD), as well as to seize dangerous infrastructure facilities, including nuclear cycle facilities, the damage or destruction of which could lead to mass casualties. Recently, the threat of terrorist acts against high-risk civilian infrastructure has increased dramatically. Military operations in Ukraine and the concomitant violation of the working rhythm of the nuclear power plant, the weakening of the security system actually open the “gates” to both provocative forceful actions and the intrigues of terrorists or groups interested in escalating the armed conflict. Computer technology and Internet resources provide new opportunities for illegal access to WMD components, which opens up new options, for instance, to the manufacture of the so-called “dirty bomb” and “bomb in the garage”. The growth of international tension not only complicates the coordinated solution of socio-economic problems in the poorest countries of the world, but also contributes to their aggravation, thereby creating conditions for a significant increase in migration flows to the most developed countries. As a result, in these countries and in the world as a whole, prerequisites are created for replenishing the ranks of terrorists. Сoordination of actions of states and international institutions, enhancing the effectiveness of the NPT regimes, of already cooperatively developed and promising measures to combat terrorism can significantly reduce this threat. Without scaling down the level of confrontation between Russia and the West, the possibility of effective collective action in this direction is now significantly hampered. Historical experience, however, shows that deep crises can create the preconditions for a return to dialogue and increased cooperation on security issues.

A new tool for the simulation of different nuclear fleets at equilibrium

Scenario simulations are the main tool for studying the impact of a nuclear reactor fleet on the related fuel cycle facilities. This equilibrium preliminary study aims to present the functionalities of a new tool and to show the wide variety of reactors/cycles/strategies that can be studied in steady state conditions and validated with more details thanks to dynamic code. Different types of scenario simulation tools have been developed at CEA over the years, this study focuses on dynamic and equilibrium codes. Dynamic fuel cycle simulation code models the ingoing and outgoing material flow in all the facilities of a nuclear reactor fleet and their evolutions through the different nuclear processes over a given period of time. Equilibrium fuel cycle simulation code models advanced nuclear fuel cycles in equilibrium conditions, i.e. in conditions which stabilize selected nuclear inventories such as spent nuclear fuel constituents, plutonium or some minor actinides. The principle of this work is to analyze different nuclear reactors (PWR, AMR) and several fuel types (UOX, MOX, ERU, MIX) to simulate advanced nuclear fleet with partial and fully plutonium and uranium multi-recycling strategies at equilibrium. At this first stage, selected results are compared with COSI6 simulations in order to evaluate the precision of this new tool, showing a significant general agreement.

Potentials and Challenges for Cycling Tourism as a Sustainable Model of Transportation for Tourist Destination Promotion– Case Study in Ella-Sri Lanka; An Exploratory Study

Presently, lots of countries have initiated sustainable approaches to destination development. As result, cycling is also promoted due to the enormous environmental benefits it offers to ensure a smokeless tourism industry. Accordingly, this study aims to identify the potential and challenges of cycling tourism as a sustainable mode of transport for destination promotion. Further, the study explores the challenges of promoting cycling along with the tourists' perception. Ella-Sri Lanka was chosen as the main study location, and for in-depth analysis, the scenario study employed a qualitative approach. Purposive sampling and semi-structured interview techniques were applied for the data collection and at the data saturation point, 20 cycling tourists' responses were recorded for data analysis. The thematic analysis method was used for data analysis. Findings associated with the benefits of cycling were divided into four main themes economic, social-cultural, environmental and health, and other benefits. Additionally, tourist perception and the related challenges were categorized under three themes namely, safety and security-related issues, product, and process-related issues, and infrastructure facilities. Finally, implications for developing a more participatory policy approach towards sustainable destination development are highlighted considering the cycle renters, tourist guides, travel agents, accommodation providers, tourist services and facility providers, local authorities, government, and other relevant stakeholder groups involved in the tourism sector.

Current state of development of industrial power complexes with fast neutron reactors

The report provides the description of the main demands, approaches and results of the design of the industrial energy complex (IPC) with fast nuclear reactors. A conceptual design (‘outline design’) of the IPC has been developed, which combines industrial reactor units with power output of 1200 MW and closed nuclear fuel cycle facilities. The main solutions and technical and economic indicators are defined. To get higher results with minimum resource spend, we implemented the way of consideration of different solutions, extensive use of digital technologies in designing, applying better solutions well-known both in the nuclear and other industries. The issue of the influence of preferred type of nuclear reactor on IPC design solutions was discussed. The perspective ways of further developments were defined.

Development of a waste‐to‐energy gasification system for sustainable communities

In this study, a geothermal energy-based integrated gasification combined cycle is incorporated with an anaerobic digestion unit to produce multiple useful commodities to create a circular economy for a sustainable community. This proposed system aims to utilize non-recyclable and unfavorable plastics, which leave material recovery facilities as a feedstock in the gasification unit to produce hydrogen, hydrogen sulfur, and electricity. Further energy is recovered in the heat recovery heat exchanger to meet the optimum temperature in the digesters where wastewater sludge is utilized to generate biogas and lower-grade compost for agricultural applications. The Durham Region in the Province of Ontario is selected to be the case location to meet the increased energy demand as a result of the growing population. Two software packages, namely Aspen Plus and Engineering Equation Solver, are used to completing the thermodynamic simulations and analyses for this system. Some parametric studies are also carried out to investigate its feasibility under different conditions and find the optimum working conditions for the integrated gasification combined cycle. Accordingly, gasification operating temperature, steam feed rate, oxygen feed rate, and carbon content in biomass are varied in both the integrated gasification combined cycle and anaerobic digestion facilities. In the proposed system, hydrogen-to-fuel and biogas-to-biomass ratios are observed to be 0.192 and 0.57, respectively, while the daily total energy delivered to the community from this integrated system is calculated to be 2.7 GWh. The overall energy and exergy efficiencies of the proposed waste management system at the chosen operating conditions are determined to be 28.1% and 30.2%, respectively. As a result of the dynamic simulations where the steam rate is varied in the gasification reactor, the energy and exergy efficiencies are determined to be 33.7% and 36.2% at the steam rate of 10 kg/s.

Techno-Economic Assessment of Fuel Cycle Facility of System Integrated Modular Advanced Reactor (SMART)

The economic assessment of advanced nuclear power reactors is very important, specifically during the early stages of concept design. Therefore, a study was performed to calculate the total cost estimation of fuel cycle supply for a system modular advanced reactor (SMART) by using the Generation-IV economic program called G4-ECONS (Generation 4 Excel-based Calculation of Nuclear Systems). In this study, the detailed description of each model and methodology are presented including facility, operations, construction matrix, post-production model, and fuel cycle cost estimation model. Based on these models, six Generation-III+ and Generation-IV nuclear reactors were simulated, namely System 80+ with benchmark data, System 80+ with uranium oxide (UOx) and mixed oxide (MOx) fuel assemblies, fast reactor, PBMR (Pebble Bed Modular Reactor), and PWR (Pressurized Water Reactor), with partially closed and benchmarked cases. The total levelized costs of these reactors were obtained, and it was observed that PBMR showed the lowest cost. The research was extended to work on the SMART reactor to calculate the total levelized fuel cycle cost, capital cost, capital component cost, fraction of capital spent, and sine curve spent pattern. To date, no work is being reported to calculate these parameters for the SMART reactor. It was observed that SMART is the most cost-effective reactor system among other proven and advanced pressurized water-based reactor systems. The main objective of the research is to verify and validate the G4-ECONS model to be used for other innovative nuclear reactors.

More than Bike Lanes—A Multifactorial Index of Urban Bikeability

The present study aims to deduce bikeability based on a collective understanding and provides a methodology to operationalize its calculation based on open data. The approach contains four steps building on each other and combines qualitative and quantitative methods. The first three steps include the definition and operationalization of the index. First, findings from the literature are condensed to determine relevant categories influencing bikeability. Second, an expert survey is conducted to estimate the importance of these categories to gain a common understanding of bikeability and merge the impacting factors. Third, the defined categories are calculated based on OpenStreetMap data and combined to a comprehensive spatial bikeability index in an automated workflow. The fourth step evaluates the proposed index using a multinomial logit mode choice model to derive the effects of bikeability on travel behavior. The expert process shows a stable interaction between the components defining bikeability, linking specific spatial characteristics of bikeability and associated components. Applied components are, in order of importance, biking facilities along main streets, street connectivity, the prevalence of neighborhood streets, green pathways and other cycle facilities, such as rental and repair facilities. The mode choice model shows a strong positive effect of a high bikeability along the route on choosing the bike as the preferred mode. This confirms that the bike friendliness on a route surrounding has a significant impact on the mode choice. Using universal open data and applying stable weighting in an automated workflow renders the approach of assessing urban bike-friendliness fully transferable and the results comparable. It, therefore, lays the foundation for various large-scale cross-sectional analyses.

Combined cycle gas turbine for combined heat and power production with energy storage by steam methane reforming

The co-generation facilities have maximal thermal efficiency. In the case of the Russian Federation, for the power production industry, the development of the co-generation combined cycle facilities (CCGT-CHP) is especially urgent. The CCGT-CHP daily load schedule requires the demand of both electricity and heat, and the heat demand depends only upon the ambient air temperature. The gas turbine power reduction and the subsequent steam turbine power reduction during the electric load drop down are limited by the necessity to maintain the steam flow to district water heater to supply heat power. Methane steam reforming allows the recovery of the excess steam heat in the form of synthetic gas together with the CCGT-CHP electric power reduction. This paper considers three versions of the CCGT-CHP steam use in the Methane reforming: Bleeding steam supply, throttling of the heat recovery steam generator exit steam and the supply of this steam to the steam production in a steam transformer. Steam Methane reforming allows a reduction in the steam turbine supply power of 25% during the electric system power drop down. In the daytime, during the maximal system load, the produced synthetic gas is used and it is necessary to use the peak load gas turbine, which allows a 23% electric power increase. Energy storage by steam Methane reforming increases the contribution margin by 2.9%.

Radon Gas Measurements in Integral Water Cycle Facilities on El Hierro (Canary Islands, Spain)

The emission of radon gas from soil is related to the uranium content of the rocks that make up the soil. In the Canary Islands, whose territory is volcanic, the uranium content of rock formations is high, so high values of radon gas concentration are expected in closed and underground places. This research, located on the island of El Hierro, is being carried out to determine the concentrations of radon gas in the island's integral water cycle facilities. The results obtained show a clear difference between underground facilities related to water collection and facilities such as desalination and water treatment plants above ground. The study was conducted in the three municipalities that make up the island and the values obtained, in general, are less than 300 Bq/m3, although the water gallery, being an underground installation, is where the highest concentration of this gas has been obtained.

Techno-Economic Analysis of the Oxy-Fuel Combustion Power Cycles with Near-Zero Emissions

This paper is devoted to improvement of environmental safety in hydrocarbon-firing TPPs. Despite the development of renewable power sources, the number of traditional power production facilities continues its growth. The toxic emission mitigation in traditional TPPs has been deeply investigated, but the problem of greenhouse gas atmospheric emissions is of topical interest. Oxy-fuel technology reduces CO2 emissions and is highly efficient and environmentally safe. Also, it requires relatively low capital investments. Thermal efficiency analysis shows that the Allam cycle facilities have the best efficiency. Their thermodynamic parameters can be optimized with minimal primary costs and capital investments. This newly developed analysis was used to compare the investment efficiency of projects for the buildup of oxy-fuel and combined cycle facilities. Without emission quote payments, the NPV of combined cycle projects is 16% higher, as well as having a lower DPP. The electricity production primary costs in oxy-fuel and combined cycle facilities are similar, which reflects the technologies’ similarity and similar fuel costs. Implementation of carbon dioxide emission quote marketing makes oxy-fuel facilities more investment-attractive. Parametric studies show that when Russia implements CO2 emission quotes compatible with the current EU level, an oxy-fuel facility erection project will be financially reasonable. Thus, it can be concluded that the construction of oxy-fuel power plants is one of the most promising and investment-attractive solutions to reduce CO2 emissions in the energy sector for large industrialized countries. The managerial consequences of their implementation will include the stabilization of greenhouse gas emissions while ensuring the financial stability of the energy industry.

Assessing cyclists\u2019 routing preferences by analyzing extensive user setting data from a bike-routing engine

IntroductionMany municipalities aim to support the uptake of cycling as an environmentally friendly and healthy mode of transport. It is therefore crucial to meet the demand of cyclists when adapting road infrastructure. Previous studies researching cyclists’ route choice behavior deliver valuable insights but are constrained by laboratory conditions, limitations in the number of observations, or the observation period or relay on specific use cases.MethodsThe present study analyzes a dataset of over 450,000 observations of cyclists’ routing settings for the navigation of individual trips in Berlin, Germany. It therefore analyzes query data recorded in the bike-routing engine BBBike and clusters the many different user settings with regard to preferred route characteristics.Results and ConclusionResults condense the large number of routing settings into characteristic preference clusters. Compared with earlier findings, the big data approach highlights the significance of short routes, side streets and the importance of high-quality surfaces for routing choices, while cycling on dedicated facilities seems a little less important.Consequentially, providing separated cycle facilities along main roads – often the main focal point of cycle plans – should be put into the context of an integrated strategy which fulfills distinct preferences to achieve greater success. It is therefore particularly important to provide a cycle network in calm residential streets as well as catering for short, direct cycle routes.

Fuel-saving performance and main losses of an organic-Rankine-cycle-based exhaust heat recovery system in heavy truck application scenarios

• Fuel-saving effect of ORC-WHR facilities on trucks are comprehensively evaluated. • Fuel-saving effect degradation due to existing components’ limitations is examined. • Fuel-saving effect degradation due to interactions in system integration is studied. • Effects of system dynamics and control strategies are explored. • It is suggested the system power density should be greater than 70 W/kg. Recovering and converting the waste heat within the exhaust gas of high-density diesel engines to mechanical or electrical energy using an organic Rankine cycle is a hotspot in recent years, and many optimistic views towards the fuel-saving capacity of this technology have been reported. But considering the off-the-shelf components’ limitations, system integration, dynamics, and other attached penalties, there lacks a comprehensive evaluation yet, especially in driving cycle scenarios. For this, a heavy truck co-simulation platform is built, embedded with organic-Rankine-cycle-based exhaust heat recovery models. Based on that the fuel-saving performance of organic Rankine cycle facilities are evaluated and main losses due to limiting factors are also discussed. It is found that an ideal subcritical organic Rankine cycle system improves the truck’s fuel economy by 4.48–7.52% when it is fully loaded. But due to the performance limitations of existing components and system interactions, the fuel-saving effect is reduced from 7.52% to 3.5%. Further considering organic Rankine cycle system dynamics and control operations, this value degrades to 2.07–2.24%, and it continues to decline with the attached weight. It is suggested that the system power density should be greater than 70 W/kg at least. At this point, its fuel-saving effect is just 1.75%.

Monitoring of atmospheric emission of alpha emitters radionuclides at a nuclear fuel cycle facility in RJ, Brazil

The Indústrias Nucleares do Brasil S/A (INB) in Resende, state of Rio de Janeiro, operate with open sources containing alpha emitters. This operation produces particulate material in the air. To reduce this impact, the plant operates with negative pressure using an exhaust equipment. Exhaust air is sent to an absolute filter system. In the exhaust stack, there is an alpha emitter detection module that operates monitoring the releases. Following the dose calculation model established by the National Commission for Nuclear Energy (CNEN), the authorized limit is fixed at 1.2∙107 Bq.y-1 of alpha emitters by Nuclear Fuel Factory (FCN). The present work aims to evaluate the alpha-emitting radionuclides released by FCN in terms of total release (Bq) and activity concentration (AC, Bq∙m-3). In 2018, FCN released 1.41∙106 Bq.y-1(i.e. 34% of the 2016 releases). The largest mean for AC was 2.04 mBq∙m-3. The release data was almost an order of magnitude lower than the annual release limit, proving the adequation of the atmospheric effluents to the licensing requirements.

Development and Studies on FBG Temperature Sensor for Applications in Nuclear Fuel Cycle Facilities

This paper presents the novel results on fiber Bragg grating temperature sensor deployment in high radiation and hazardous chemical environment of nuclear fuel recycle facility. The sensor is developed using thermally regenerated grating obtained from the thermal annealing of seed type-I grating inscribed in telecommunication fiber. The studies on the operating life time and average sensitivity of regenerated grating were carried out upto 900 °C. For the remaining reflectivity of $\sim 5$ % at 900 °C, the predicted lifetime of the grating was around 4 year. The radiation hardness of the packaged FBG sensor was tested in high radiation environment upto 1 MGy. Bragg wavelength shift of $\sim 35$ pm was observed after 1 MGy accumulated gamma radiation dose. Developed and characterized FBG sensor was finally deployed for temperature monitoring of nuclear fuel recycling chamber. Reliable and accurate temperature measurement helped to precisely control the process and to avoid the spill over of uranium, plutonium nitrate solution in the microwave heated process chamber.

Model design of a deuterium-deuterium neutron generator moderator and evaluation for delayed gamma-ray nondestructive assay for safeguards verification

ABSTRACT The Japan Atomic Energy Agency is evaluating delayed gamma-ray spectroscopy as an active interrogation nondestructive assay technique to quantify the fissile composition of nuclear materials for improved safeguards verification in nuclear fuel cycle facilities. In this paper, we optimize a moderator to thermalize the 2.5 MeV neutrons emitted from a deuterium–deuterium (D–D) neutron generator. The moderator is optimized to maximize the thermal neutron flux, maintain a high moderator quality factor, and be compact for easy installation in the analytical laboratories of reprocessing facilities. With the objective of applying our system to high-radioactivity nuclear materials (e.g. spent fuel solution), we applied this moderator’s flux to an interrogation using delayed gamma-ray spectroscopy for various sample sizes and timing patterns. The results indicate that our 78-cm3 system is sufficiently able to use commercially available D–D neutron generators with neutron emission rates less than 109 n/s for 25- and 100-ml solutions under specific interrogations.

Demand-Driven Deployment Capabilities in Cyclus, a Fuel Cycle Simulator

The present U.S. nuclear fuel cycle faces challenges that hinder the expansion of nuclear energy technology. The U.S. Department of Energy identified four nuclear fuel cycle options that make nuclear energy technology more desirable. Successfully analyzing the transitions from the current fuel cycle to these promising fuel cycles requires a nuclear fuel cycle simulator that can predictively and automatically deploy fuel cycle facilities to meet user-defined power demand. This work introduces and demonstrates the demand-driven deployment capabilities in Cyclus, an open-source nuclear fuel cycle simulator framework. User-controlled capabilities such as time-series forecasting algorithms, supply buffers, and facility preferences were introduced to give users tools to minimize power undersupply in a transition scenario simulation. The demand-driven deployment capabilities are referred to as d3ploy. We demonstrate the capability of d3ploy to predict future commodities’ supply and demand, and automatically deploy fuel cycle facilities to meet the predicted demand in four transition scenarios. Using d3ploy to set up transition scenarios saves the user simulation setup time compared to previous efforts that required a user to manually calculate and use trial and error to set up the deployment scheme for the supporting fuel cycle facilities.