bluuebunny/crossref_metadata_2025 huggingface dataset:
Integrating Natural and Social Sciences to Inspire Public Confidence in Radioactive Waste Policy Case Study: Committee on Radioactive Waste Management
Authors: Usher Sam
Published: June 2009

Implementing effective long-term radioactive waste management policy is challenging, and both UK and international experience is littered with policy and programme failures. Policy must not only be underpinned by sound science and technical rationale, it must also inspire the confidence of the public and other stakeholders. However, in today’s modern society, communities will not simply accept the word of scientists for setting policy based purely on technical grounds. This is particularly so in areas where there are significant social and ethical issues, such as radioactive waste disposal. To develop and implement effective policy, governments, waste owners and implementing bodies must develop processes which effectively integrate both complex technical and scientific issues, with equally challenging social and ethical concerns. These integrating processes must marry often intricate technical issues with broad public and stakeholder engagement programmes, in programmes which can expect the highest levels of public scrutiny, and must invariably be delivered within challenging time and budget constraints. This paper considers a model for how such integrating processes can be delivered. The paper reviews, as a case study, how such challenges were overcome by the Committee on Radioactive Waste Management (CoRWM), which, in July 2006, made recommendations to the UK government for the establishment of a long-term radioactive waste policy. Its recommendations were underpinned by sound science, but also engendered public confidence through undertaking the largest and most significant deliberative public and stakeholder engagement programme on a complex policy issue in the UK. Effective decision-making was enabled through the integration of both proven and bespoke methodologies, including Multi-criteria Decision Analysis and Holistic assessments, coupled with an overarching deliberative approach. How this was managed and delivered to programme demonstrates how important effective integration of different issues, interests and world views can be achieved, and the paper looks forward to how the continued integration of both natural and social sciences is essential if public confidence is to be maintained through implementation stages. This paper will be particularly relevant to governments, waste owners and implementing bodies who are responsible for developing and implementing policy.
The ZWILAG Interim Storage Plasma Plant: Technology to Handle Operational Waste From Nuclear Plants
Authors: Heep Walter
Published: June 2009

The first processing of low level radioactive wastes from Swiss nuclear power plants marks the successful completion of commissioning in March 2004 of a treatment facility for low and intermediate level radioactive wastes, which is operated with the help of plasma technology. The theoretical principles of this metallurgy-derived process technology are based on plasma technology, which has already been used for a considerable period outside of nuclear technology for the production of highly pure metal alloys and for the plasma synthesis of acetylene. The commercial operation of the Plasma Plant owned by Zwischenlager Wuerenlingen AG (ZWILAG) has also enabled this technology to be used successfully for the first time in the nuclear field, especially in compliance with radiation protection aspects. In addition to a brief presentation of the technology used in the plant, the melting process under operating conditions will be explained in more detail. The separation factors attained and volume reductions achieved open interesting perspectives for the further optimisation of the entire process in the future.
Development of the Sampling and Nuclide Analysis Methods for Spent HEPA Filter Wastes
Authors: Ji Young-Yong , Hong Dae Seok , Kang Il-Sik , Seo Bum-Kyoung , Shon Jong-Sik
Published: June 2009

Spent filter wastes of about 2,160 units have been stored in the waste storage facility of the Korea Atomic Energy Research Institute since its operation. These spent filters have generally consisted of a HEPA filter after its filtering of all the contaminants in the gas stream generated during the operation of the HANARO research reactor and the nuclear fuel cycle facilities. At the moment, to secure enough storage space, it is necessary to make a volume reduction of the stored radioactive wastes through a compression treatment or a regulatory clearance. There have been many studies on a treatment and a clearance of the low level radioactive wastes generated from nuclear facilities. These methods are used in view of a reduction of a management cost and disposal cost and the security of free space for a waste storage facility approaching saturation. In order to dispose of the spent filters, it is first necessary to conduct a radionuclide assessment of them. To do that, a sampling procedure should be prepared to obtain a representative sample from a spent filter. As for conducting a nuclide analysis for this representative sample, a corresponding spent filter can be determined as either a regulatory clearance waste or a radioactive waste.
Global Partnering Related to Nuclear Materials Safeguards and Security: A Pragmatic Approach to International Safeguards Work
Authors: Stanford Dennis
Published: June 2009

This paper documents issues Nuclear Fuel Services, Inc. has addressed in the performance of international work to safeguards and security work. It begins with a description of the package we put together for a sample proposal for the Global Threat Reduction Initiative, for which we were ranked number one for technical approach and cost, and concludes with a discussion of approaches that we have taken to performing this work, including issues related to performing the work as part of a team. The primary focus is on communication, workforce, equipment, and coordination issues. Finally, the paper documents the rules that we use to assure the work is performed safely and successfully.
Systematic Approach to Radioactive Waste Characterization at Belgoprocess
Authors: Huys T. , Gielen P.
Published: June 2009

Belgoprocess is capable of processing almost every type of low and medium level radioactive waste and thereby covering a large segment from the back-end of the nuclear fuel cycle. Waste from numerous producers is treated and conditioned into a stable end product. Such processes lead inevitably to the generation of a large number of different waste streams. Each of these streams is uniquely defined by its radiological and physicochemical characteristics. From regulatory point of view and in order to select appropriate processing and conditioning techniques it is essential to characterize each of these waste streams. Because of the labour-intensive nature of the work and to keep a trustworthy traceability, Belgoprocess has decided to automate this task as far as possible. Therefore it has developed a system that seamlessly integrates waste-accounting and radiological characterization into one system. The use of generic methodologies, isotope vectors and a measurement database makes it possible to characterize most waste packages without elaborate knowledge of radiological characterization. A nuclear engineer develops generic methodologies and defines isotope vectors and appropriate measurements. These combinations are documented in procedures and used by the waste-accounting team to characterize the waste packages. The whole system is designed and programmed in such a way that it offers maximum flexibility and traceability. For example, changes in characterization of the previously processed and conditioned waste will propagate through the system until the changes reach the end product. This kind of systematic approach to radioactive waste characterization is found to be very fruitful.
The Role of Tetronics Plasma Vitrification Technology in the Management and Conditioning of Nuclear Waste
Authors: Deegan David , Scales Charlie
Published: June 2009

Plasma Arc Technology is finding wider application in the treatment of hazardous waste materials an area which has a lot of synergy with radioactive waste management. It is being stimulated by the increasing demands of regulatory and economic drivers; currently, within the Integrated Waste Management (IWM) sector, there is a climate of rising costs, limited numbers of technological solutions, restricted access to traditional disposal based solutions and a significant levels of market consolidation. Traditionally, the IWM sector has operated with basic mixing technology solutions: e.g. physiochemical consolidation, physiochemical separation, neutralisation and basic material bulking, with ultimate reliance on landfill, cement based encapsulation and high temperature incineration (HTI). The impact of national statutes, the value of national liabilities and infrastructural deficiencies is demanding constant technological advancement for continued regulatory compliance. This paper presents information on Tetronics’ plasma based solution, for the treatment of Asbestos Containing Materials (ACM) and Plutonium Containing Material (PCM).
Solid Radioactive Waste Management Facility Design for Managing Candu® 600 MW Nuclear Generating Station Retube/Refurbishment Waste Streams
Authors: Pontikakis N. , Scott D. , Hopkins J. , Bajaj V. , Nosella L.
Published: June 2009

The main design features of the retube canisters, waste handling equipment and waste containers designed by Atomic Energy of Canada Limited (AECL®) and implemented in support of the retube/refurbishment activities for CANDU 600 MW nuclear generating stations are described in this paper. The retube/refurbishment waste characterization and the waste management principles, which form the basis of the design activities are also briefly outlined.
Removal of Alkaline-Earth Elements by a Carbonate Precipitation in a Chloride Molten Salt
Authors: Cho Yung-Zun , Kim In-Tae , Yang Hee-Chul , Eun Hee-Chul , Park Hwan-Seo , Kim Eung-Ho
Published: June 2009

Separation of some alkaline-earth chlorides (Sr, Ba) was investigated by using carbonate injection method in LiCl-KCl eutectic and LiCl molten salts. The effects of the injected molar ratio of carbonate ([K2 (or Li2)CO3/Sr (or Ba)Cl2]) and the temperature (450–750 °C) on the conversion ratio of the Sr or Ba carbonate were determined. In addition, the form of the Sr and Ba carbonate resulting from the carbonation reaction with carbonates was identified via XRD and SEM-EDS analysis. In these experiments, the carbonate injection method can remove Sr and Ba chlorides effectively over 99% in both LiCl-KCl eutectic and LiCl molten salt conditions. When Sr and Ba were co-presented in the eutectic molten salt, they were carbonated in a form of Ba0.5Sr0.3CO3. And when Sr was present in LiCl molten salt, it was carbonated in the form of SrCO3. Carbonation ratio increased with a decreasing temperature and it was more favorable in the case of a K2CO3 injection than that of Li2CO3. Based on this experiment, it is postulated that carbonate precipitation method has the potential for removing alkali-earth chlorides from LiCl-KCl eutectic and LiCl molten salts.
Bonding Material Containing Ashes After Domestic Waste Incineration for Cementation of Radioactive Waste
Authors: Dmitriev S. A. , Varlakov A. P. , Gorbunova O. A. , Arustamov A. E. , Barinov A. S.
Published: June 2009

It is known that cement minerals hydration is accompanied with heat emission. Heat of hardening influences formation of a cement compound structure and its properties. It is important to reduce the heat quantity at continuous cementation of waste and filling of compartments of a repository or containers by a cement grout. For reduction of heating, it is necessary to use cement of mineral additives (fuel ashes, slag and hydraulic silica). Properties of ashes after domestic waste incineration can be similar to ones of fly fuel ashes. However, ash after domestic waste incineration is toxic industrial waste as it contains toxic elements (As, Cd, Hg, Pb, Sb, Zn). Utilization of secondary waste (slag and ash) of combustion plants is an important environmental approach to solving cities’ issues. Results of the research have shown that ashes of combustion plants can be used for radioactive waste conditioning. Coprocessing of toxic and radioactive waste is ecologically and economically effective. At SIA “Radon”, experimental batches of cement compositions are used for cementation of oil containing waste.
Environmental Impact Assessment (EIA) Process of V1 NPP Decommissioning
Authors: Matejovicˇ Igor , Pola´k Vincent
Published: June 2009

Through the adoption of Governmental Resolution No. 801/99 the Slovak Republic undertook a commitment to shutdown units 1 and 2 of Jaslovske´ Bohunice V1 NPP (WWER 230 reactor type) in 2006 and 2008 respectively. Therefore the more intensive preparation of a decommissioning documentation has been commenced. Namely, the V1 NPP Conceptual Decommissioning Plan and subsequently the Environmental Impact Assessment Report of V1 NPP Decommissioning were developed. Thus, the standard environmental impact assessment process was performed and the most suitable alternative of V1 NPP decommissioning was selected as a basis for development of further decommissioning documents. The status and main results of the environmental impact assessment process and EIA report are discussed in more detail in this paper.
Decommissioning: An Approach to Predict the Amount of Radioactive Waste Arisings
Authors: Kugel K. , Brennecke P. , Koch W.
Published: June 2009

In the next decades many facilities are going to be decommissioned in Germany. On the basis of the agreement between the utilities and the Federal Government on the phase out of nuclear energy use for commercial electricity generation predictions can be made on the schedule of the shut down of nuclear installations in Germany and a prognosis might be given for the complete amount of decommissioning waste that will arise. 17 nuclear power plants and other nuclear installations are to be shut down and decommissioned within the next 2 decades. An approach for the prediction of the amount of radioactive waste and an overview on the underlying assumptions is given. The prognosis for the expected radioactive waste in Germany depends on several assumptions. Utilities in Germany expect approx. 5000 m3 of radioactive waste with negligible heat-generation from decommissioning per reactor. New inquiries seem to indicate that less radioactive waste may arise due to new techniques in decontamination and conditioning. Nevertheless, there will be limits due to costs and physical properties.
Sharing Lessons Learned and Best Practices in Deactivation and Decommissioning Techniques Among U.S. Department of Energy Contractors
Authors: Lackey Michael B. , Waisley Sandra L. , Dusek Lansing G.
Published: June 2009

Approximately $153.2 billion of work currently remains in the United States Department of Energy’s (DOE’s) Office of Environmental Management (EM) lifecycle budget for United States projects. Contractors who manage facilities for the DOE have been challenged to identify transformational changes to reduce the lifecycle costs and develop a knowledge management system that identifies, disseminates, and tracks the implementation of lessons learned and best practices. At the request of the DOE’s EM Office of Engineering and Technology, the Energy Facility Contractors Group (EFCOG) responded to the challenge with formation of the Deactivation and Decommissioning (D&D) and Facility Engineering (DD/FE) Working Group. Since October 2006, members have already made significant progress in realizing their goals: adding new D&D best practices to the existing EFCOG Best Practices database; participating in lessons learned forums; and contributing to a DOE initiative on identifying technology needs. The group is also participating in a DOE project management initiative to develop implementation guidelines, as well as a DOE radiation protection initiative to institute a more predictable and standardized approach to approving authorized limits and independently verifying cleanup completion at EM sites. Finally, a D&D hotline to provide real-time solutions to D&D challenges is also being launched.
Dose Rate Effects on the Accumulation of Radiation Damage
Authors: Rondinella V. V. , Wiss T. , Hiernaut J.-P. , Staicu D.
Published: June 2009

During storage, spent fuel and other waste forms accumulate alpha-decay damage (and He). The dose rates and the temperatures experienced during storage are lower than during in-pile operation: however, the duration of the storage is much longer (of the order of up to a few hundred years if extended interim storage concepts are considered); if final disposal in the repository is considered, the time interval in which radiation damage accumulates is open-ended. In order to simulate within timeframes suitable for laboratory experiments long-term accumulation of alpha-decay damage, the so-called alpha-doped materials can be used, i.e. materials loaded with short-lived alpha-emitters (like e.g. Pu-238, U-233, etc.). The question is often posed if the accelerated accumulation of decay damage and He obtained using alpha-doped materials does cause some artefact related to the rate of accumulation rather than by the integrated dose. This work presents evidence that, at least within the range of alpha-activities considered, there is no dose rate effect. By comparing property evolution as a function of accumulated dpa for alpha-doped materials with activities of ∼1010 and ∼108 Bq/g, respectively, the same trends and levels of alteration are observed. In particular, macroscopic properties like hardness (measured by Vickers indentation) or swelling (evolution of lattice parameter derived from XRD), and microstructural formation and accumulation of defects in the lattice of the alpha-doped material are investigated, showing a remarkable similarity of behaviour vs. dpa independently not only from the dose rate, but also from the composition (namely, Pu and U are considered).
Risk Newsboy: Approach for Addressing Uncertainty in Developing Action Levels and Cleanup Limits
Authors: Cooke Roger , MacDonell Margaret
Published: June 2009

Site cleanup decisions involve developing action levels and residual limits for key contaminants, to assure health protection during the cleanup period and into the long term. Uncertainty is inherent in the toxicity information used to define these levels, based on incomplete scientific knowledge regarding dose-response relationships across various hazards and exposures at environmentally relevant levels. This problem can be addressed by applying principles used to manage uncertainty in operations research, as illustrated by the newsboy dilemma. Each day a newsboy must balance the risk of buying more papers than he can sell against the risk of not buying enough. Setting action levels and cleanup limits involves a similar concept of balancing and distributing risks and benefits in the face of uncertainty. The newsboy approach can be applied to develop health-based target concentrations for both radiological and chemical contaminants, with stakeholder input being crucial to assessing “regret” levels. Associated tools include structured expert judgment elicitation to quantify uncertainty in the dose-response relationship, and mathematical techniques such as probabilistic inversion and iterative proportional fitting.
Electrolytic Recycling of a Carbonate Salt in a Process With a Dissolution of Spent Nuclear Fuel in a Strong Alkaline Carbonate Media
Authors: Kim Kwang-Wook , Kim In-Tae , Kim Seong-Min , Kim Yeon-Hwa , Lee Eil-Hee , Jee Kwang-Yong
Published: June 2009

A removal of only uranium from spent nuclear fuel with the concepts of a high proliferation-resistance and a minimal generation of waste is helpful for a spent fuel management in view of a volume reduction of the high level radioactive waste generated from the spent fuel treatment. That can be accomplished by a process using a selective oxidative dissolution of the spent fuel in a carbonate solution of high alkalinity. In this work, an electrolytic method for a decarbonation and a recovery of CO2 for recycling the used carbonate solution contaminated with some impurity metal ions generated in such a process with a concept of zero-release of waste solution was studied. A carbonate solution generated from such a system was confirmed to be completely recycled within the system, while the impurity ions being separated from the carbonate solution.
Thermal Treatment of Historical Radioactive Solid and Liquid Waste Into the CILVA Incinerator
Authors: Deckers Jan , Mols Ludo
Published: June 2009

Since the very beginning of the nuclear activities in Belgium, the incineration of radioactive waste was chosen as a suitable technique for achieving an optimal volume reduction of the produced waste quantities. Based on the 35 years experience gained by the operation of the old incinerator, a new industrial incineration plant started nuclear operation in May 1995, as a part of the Belgian Centralized Treatment/Conditioning Facility named CILVA. Up to the end of 2006, the CILVA incinerator has burnt 1660 tonne of solid waste and 419 tonne of liquid waste. This paper describes the type and allowable radioactivity of the waste, the incineration process, heat recovery and the air pollution control devices. Special attention is given to the treatment of several hundreds of tonne historical waste from former reprocessing activities such as alpha suspected solid waste, aqueous and organic liquid waste and spent ion exchange resins. The capacity, volume reduction, chemical and radiological emissions are also evaluated. BELGOPROCESS, a company set up in 1984 at Dessel (Belgium) where a number of nuclear facilities were already installed is specialized in the processing of radioactive waste. It is a subsidiary of ONDRAF/NIRAS, the Belgian Nuclear Waste Management Agency. According to its mission statement, the activities of BELGOPROCESS focus on three areas: treatment, conditioning and interim storage of radioactive waste; decommissioning of shut-down nuclear facilities and cleaning of contaminated buildings and land; operating of storage sites for conditioned radioactive waste.
Study of the Oxidation State of Arsenic and Uranium in Individual Particles From Uranium Mine Tailings, Hungary
Authors: Alsecz A. , Osa´n J. , Pa´lfalvi J. , Sajo´ I. , Ma´the´ Z. , Simon R. , To¨ro¨k Sz. , Falkenberg G.
Published: June 2009

Uranium ore mining and milling have been terminated in the Mecsek Mountains (southwest Hungary) in 1997. Mine tailings ponds are located between two important water bases, which are resources of the drinking water of the city of Pe´cs and the neighbouring villages. The average U concentration of the tailings material is 71.73 μg/g, but it is inhomogeneous. Some microscopic particles contain orders of magnitude more U than the rest of the tailings material. Other potentially toxic elements are As and Pb of which chemical state is important to estimate mobility, because in mobile form they can risk the water basis and the public health. Individual U-rich particles were selected with solid state nuclear track detector (SSNTD) and after localisation the particles were investigated by synchrotron radiation based microanalytical techniques. The distribution of elements over the particles was studied by micro beam X-ray fluorescence (μ-XRF) and the oxidation state of uranium and arsenic was determined by micro X-ray absorption near edge structure (μ-XANES) spectroscopy. Some of the measured U-rich particles were chosen for studying the heterogeneity with μ-XRF tomography. Arsenic was present mainly in As(V) and uranium in U(VI) form in the original uranium ore particles, but in the mine tailings samples uranium was present mainly in the less mobile U(IV) form. Correlation was found between the oxidation state of As and U in the same analyzed particles. These results suggest that dissolution of uranium is not expected in short term period.
Workforce Issues and Training Programmes: A UK Perspective
Authors: Richards Warren
Published: June 2009

Over the past 20 years underinvestment has led to the UK’s nuclear skills base being run down to the point where it is now very fragile and the cracks are showing. As a result a number of key nuclear science and engineering disciplines are now showing signs of shortages developing which is being reflected in both industry and academia. Fortunately, the skills gap has been recognised and the trend of underinvestment is being reversed. Industry, Government and the Research Councils are starting to take steps to address the issue and new nuclear education and research initiatives are underway including the Dalton Nuclear Institute and the plans to create a National Nuclear Laboratory. The concern over a skills gap still exists but hopefully with the realisation of high profile projects such as new nuclear build, the establishment of a National Nuclear Laboratory and continued support from the UK’s Research Councils, involvement in the nuclear field will prove to be an attractive career option for a greater number of people which will put the UK back in the position of having a vibrant and sustainable world class nuclear skills base.
Environmental Radioactivity Assessment Around Old Uranium Mining Sites Near Mangualde (Viseu), Portugal
Authors: Carvalho Fernando P. , Oliveira Joa˜o M. , Torres Lube´lia M.
Published: June 2009

Uranium ore was extracted in the surroundings of Mangualde city, North of Portugal, in the mines of Cunha Baixa, Quinta do Bispo and Espinho until a few years ago. Mining waste, milling tailings and acid mine waters are the on site remains of this extractive activity. Environmental radioactivity measurements were performed in and around these sites in order to assess the dispersal of radionuclides from uranium mining waste and the spread of acidic waters resulting from the in situ uranium leaching with sulphuric acid. Results show migration of acid waters into groundwater around the Cunha Baixa mine. This groundwater is tapped by irrigation wells in the agriculture area near the Cunha Baixa village. Water from wells displayed uranium (238U) concentrations up to 19 × 103 mBq L−1 and sulphate ion concentrations up to 1070 mg L−1. These enhanced concentrations are positively correlated with low water pH, pointing to a common origin for radioactivity, dissolved sulphate, and acidity in underground mining works. Radionuclide concentrations were determined in horticulture and farm products from this area also and results suggest low soil to plant transfer of radionuclides and low food chain transfer of radionuclides to man. Analysis of aerosols in surface air showed re suspension of dust from mining and milling waste heaps. Therefore, it is recommended to maintain mine water treatment and to plan remediation of these mine sites in order to prevent waste dispersal in the environment.
Agriculture in an Area Impacted by Past Uranium Mining Activities
Authors: Carvalho F. P. , Oliveira J. M. , Neves O. , Abreu M. M. , Vicente E. M.
Published: June 2009

The shallow aquifer near the old Cunha Baixa uranium mine (Viseu, Portugal) was contaminated by acid mine drainage. Concentration of radionuclides in water from irrigation wells and in the topsoil layer of the agriculture fields nearby display enhanced concentrations of uranium, radium and polonium. Two types of agriculture land in this area were selected, one with enhanced and another with low uranium concentrations, for controlled growth of lettuce and potatoes. Plants were grown in replicate portions of land (two plots) in each soil type and were periodically irrigated with water from wells. In each soil, one plot was irrigated with water containing low concentration of dissolved uranium and the other plot with water containing enhanced concentration of dissolved uranium. At the end of the growth season, plants were harvested and analysed, along with soil and irrigation water samples. Results show the accumulation of radionuclides in edible parts of plants, specially in the field plots with higher radionuclide concentrations in soil. Radionuclides in irrigation water contributed less to the radioactivity accumulated in plants than radionuclides from soils.
Research on Thermal Stability of Sorbents on the Basis of Microspheres Modified With Ferrocyanides of Transient and Heavy Metals
Authors: Danilin Lev , Drozhzhin Valery
Published: June 2009

The mass-spectrometer method was used to investigate the compositions of gas phases formed at thermal decomposition of inorganic sorbents on the basis of alumosilicate microspheres modified with ferrocyanides of copper, iron, cobalt, tungsten and vanadium. The research was carried out in a static mode in vacuum in the temperature range of 180–500°C. The chemical composition of modifiers corresponded to formulas: K2Cu[Fe(CN)6]; K2Cu3[Fe(CN)6]2; Fe4[Fe(CN)6]3; KFe[Fe(CN)6]; Co2[Fe(CN)6]; xH4Fe(N)6·yWO3·zH2O; xH4Fe(CN)6·yV2O5·zH2O. The basic components of gas phases after thermal effect on these structures are hydrogen, water, carbon dioxide and monoxide, nitrogen, and cyanic hydrogen. With the temperature growth the intensity of gas evolution increases, the ratio between the components vary, paraffin hydrocarbons and unsaturated hydrocarbons appear (ethane, acetylene, propene). The content of methane varies within ∼0.2–2 % vol. weakly correlating with experimental conditions. The composition of the gas phases produced during thermal effect on the modified microspheres is most probably a superposition of physical and chemical processes connected with the influence of the matrix itself, with individual heat resistance of the modifiers and products of their decomposition, as well as with that circumstance, that products of reactions can interact with each other. In general the character of the processes during thermal decomposition of mixed ferrocyanides of MxEy[Fe(CN)6]z type (where M is an alkali metal, and E is some “heavy metal”) applied onto cenocpheres is determined mostly by the polarization effect of the “heavy” metal on anion [Fe(CN)6]−4.
Radiological Aspects of In Situ Uranium Recovery
Authors: Brown Steven H.
Published: June 2009

In the last few years, there has been a significant increase in the demand for Uranium as historical inventories have been consumed and new reactor orders are being placed. Numerous mineralized properties around the world are being evaluated for Uranium recovery and new mining / milling projects are being evaluated and developed. Ore bodies which are considered uneconomical to mine by conventional methods such as tunneling or open pits, can be candidates for non-conventional recovery techniques, involving considerably less capital expenditure. Technologies such as Uranium in situ leaching in situ recovery (ISL / ISR), have enabled commercial scale mining and milling of relatively small ore pockets of lower grade, and may make a significant contribution to overall world wide uranium supplies over the next ten years. Commercial size solution mining production facilities have operated in the US since 1975. Solution mining involves the pumping of groundwater, fortified with oxidizing and complexing agents into an ore body, solubilizing the uranium in situ, and then pumping the solutions to the surface where they are fed to a processing plant. Processing involves ion exchange and may also include precipitation, drying or calcining and packaging operations depending on facility specifics. This paper presents an overview of the ISR process and the health physics monitoring programs developed at a number of commercial scale ISL / ISR Uranium recovery and production facillities as a result of the radiological character of these processes. Although many radiological aspects of the process are similar to that of conventional mills, conventional-type tailings as such are not generated. However, liquid and solid by product materials may be generated and impounded. The quantity and radiological character of these by products are related to facility specifics. Some special monitoring considerations are presented which are required due to the manner in which Radon gas is evolved in the process and the unique aspects of controlling solution flow patterns underground. An overview of the major aspects of the health physics and radiation protection programs that were developed at these facilities are discussed and contrasted to circumstances of the current generation and state of the art of Uranium ISR technologies and facilities.
Technology for NPP Decantate Treatment Realized at Kola NPP
Authors: Kornev V. I. , Dmitriev S. A. , Savkin A. E. , Fedorov D. A. , Stakhiv M. R. , Avezniyasov S. R.
Published: June 2009

At Moscow SIA “Radon” jointly with JSC “Alliance Gamma”, the technology for NPP Decanatate Treatment was developed, tested and realized at Kola NPP. This technology consists of dissolving the salt residue and subsequent treatment by ozonization, separation of the deposits formed from ozonization and selective cleaning by ferro-cyanide sorbents. The nonactive salt solution goes to an industrial waste disposal site or a repository specially developed at NPP sites for “exempt waste” products by IAEA classification. This technology was realized at Kola NPP in December 2006 year. At this time more than 1000 m3 of decantates log time stored are treated. It allows solving very old problem to empty decantates’ tanks at NPPs in environmentally safe manner and with high volume reduction factor.
Micro Pattern Filling Simulation to See the Effects of Process Parametric Variables on Imprinting
Authors: Mok Jinho , Lee Sukwon , Ryu JeHyoung , Kim Hyuk , Kwon Sin , Baek Seong-Gu , Park Jung-Woo , Seo Jungwoo
Published: June 2009

The nano imprint lithography, a new approach to lithography, is a very useful alternative for the conventional photolithography process. To apply this new technology to the lithography process, new equipment, process parameters and post processes must be taken into consideration. If the defects during imprinting can be detected by optical measuring only after finishing the whole process, the engineers have no choice but analyze the sample of a final form to analogize the cause of defects. To set up the optimal process conditions, simulation is a very useful method in terms of not only the minimum number of trial and error but also the quantitative data based design. In this study, a few process parameters that affect the micro pattern forming in the nano imprint process are chosen and examined to present the quantitative data useful to set up the process conditions for the residual bubble free process.
Separation of Micro Particles and Biological Cells Inside an Evaporating Droplet Using Dielectrophoresis
Authors: Jung Jung-Yeul , Kwak Ho-Young
Published: June 2009

Micro particles or biological cells mixed in water solution was shown to be separated using the combined electrical force due to dielectrophoresis and mechanical one generated in an evaporating droplet. Micro patterned electrodes of Au were fabricated on the silicon dioxide layer and were used for generating dielectrophoresis. Polystyrene particles, red blood cells and E-coli were used for separating objects. Micro particles and biological cells were separated by adjusting the amplitude and frequency of the applied voltage. The mechanical force is enough to transport the particles to the boundary of the droplet, nevertheless it could not detach the particles trapped at the electrode. Based on this work, the micro particles and biological cells can be separated, controlled and sensed without liquid pumping unit.
Mocrochannel Evaporators of the Residential Air-Conditioner
Authors: Cho Honggi , Cho Keumnam
Published: June 2009

The objective of present work was to evaluate the performance of microchannel evaporators of the residential air-conditioner using R-22. Six prototype evaporators were manufactured and tested with psychrometric calorimeter test facilities. The test was conducted in two different ways. Each evaporator consisted of two parallel flow type heat exchangers connected with several return pipes. The heat exchanger had 41 microchannel tubes that had 8 rectangular ports with the hydraulic diameter of 1.3 mm. For the vapor compression system (VCS), the flow area ratio and the number of return pipe had a great effect on the cooling capacity. Type 3 with the flow area ratio of 73/ 58% showed best cooling capacity. The effect of the number of circuit and merging manifold on the cooling capacity was relatively small. For the refrigerant circulation system (RCS), the cooling capacity of the test evaporators was a little bit changed as the mass flow rate and inlet quality increased. The effect of mass flow rate on the cooling capacity was slightly superior to that of inlet quality. The effect of the number of circuit on the cooling capacity was different with the result of the VCS, while the effect of merging manifold was negligible. The cooling capacity proportionally increased as the vertical inclination angle of the evaporator increased due to gravity force.
Estimating Roughness Parameters Resulting From Various Machining Techniques for Fluid Flow Applications
Authors: Young Perry L. , Brackbill Timothy P. , Kandlikar Satish G.
Published: June 2009

Recently, a set of new roughness parameters was proposed by Kandlikar et al. [1] and Taylor et al. [2] for reporting surface roughness as related to fluid flow. The average roughness Ra parameter is often used in microfluidic applications, but this parameter alone is insufficient for describing surface roughness; a specimen with deep grooves and sharp obstructions can share the same average roughness value as a relatively smooth surface with low uniform surface roughness. Since the average roughness parameter is broad, it is difficult to access the surface topography features that result from different machining processes or etches. A profilometer and a digital microscope are used to examine the surface roughness profiles of various materials submitted to different machining techniques. The materials studied will be similar to those used for microchannels including aluminum, stainless steel, copper, and silicon. Depending on the material, these samples are submitted to several machining processes including milling, grinding, fly cutting, and microfabrication techniques. These machining processes and microfabrication techniques are of practical interest in microfluidics applications. After studying the surface roughness patterns exhibited in these samples, the roughness parameters employed in some of the recent roughness models are evaluated. This study is expected to provide more understanding of assorted surface roughness.
Heat Transfer Predictions for Micro/Nano-Channels at Atomistic Level Using Combined Molecular Dynamics and Monte Carlo Techniques
Authors: Nedea S. V. , Markvoort A. J. , van Steenhoven A. A. , Hilbers P. A. J.
Published: June 2009

The thermal behavior of a gas confined between two parallel walls is investigated. Wall effects like hydrophobic or hydrophilic wall interactions are studied, and the effect on the heat flux and other characteristic parameters like density and temperature is shown. For a dilute gas, the dependence on gas-wall interactions of the temperature profile between the walls for the incident and reflected molecules is obtained using Molecular Dynamics. From these profiles, the effective accomodation coefficients for different interactions and different mass fluid/wall ratio are derived. We show that MC with Maxwell boundary conditions based on the accomodation coefficient gives good results for heat flux predictions when compared to pure Molecular Dynamics simulations. We use these effective coefficients to compute the heat flux predictions for a dense gas using MD and MC with Maxwell-like boundary conditions.
Thermal Gradient Driven Flow
Authors: Me´olans J. Gilbert , Graur Irina A.
Published: June 2009

A thermal creep process is studied in a wide rectangular micro channel considered as two infinite parallel plates. The inlet and outlet reservoirs are kept at the same constant pressure. A constant temperature gradient exists along the walls of the channel joining the two tanks. Thus a gas flow is induced and thermally sustained until steady conditions are reached. A complete steady analytical solution is derived in slip regime for Knudsen numbers smaller than 0.25. The analytical results are in good agreement with the numerical “exact” solution of the continuum equations system. Furthermore our continuum approach results are compared to those deduced from the approaches based on the Boltzmann equation model treatments: these various methods lead generally to a satisfactory agreement between their respective mean parameters. Nevertheless significant differences appear on the transversal velocity profiles in the close vicinity of the wall.
Rapid Prototyping of PDMS Devices With Applications to Protein Crystallization
Authors: Gonzalez-Domenzain Walter , Seshia Ashwin A.
Published: June 2009

This paper describes a microfabrication process for constructing three-dimensional microfluidic structures in polydimethylsiloxane (PDMS). Rapid prototyping of microfluidic devices is possible starting from ink-jet printed masks and by utilising replica molding to create fluidic structures in PDMS from SU-8 and SPR-220 masters pre-patterned on a silicon or glass substrate. Multi-layer bonded and stacked alignment of up to 13 different functional polymer microfluidic layers with through-layer fluidic interconnects has been demonstrated. Pneumatically actuated valves have also been demonstrated for the regulation of sub-10 nL of fluid volumes. The geometric design of the valves is described with experimental verification conducted on rounded and vertical channel profiles to examine the effects of channel geometry on valve leak rates. The PDMS-based technology allows for the fabrication of devices with extremely small reaction volumes and parallel sample processing, making these devices ideally suited to applications which require high throughput processing and the ability to conduct parallel assays with very limited volumes of reagent and sample. We describe the applications of this technology to protein crystallization in particular.
Insulator Based Dielectrophoresis: Effects of Bulk Medium Properties
Authors: Lapizco-Encinas Blanca H. , Ozuna-Chaco´n Sandra , Rito-Palomares Marco , Reyes-Betanzo Claudia , Collado-Arredondo Esther , Marti´nez-Chapa Sergio O.
Published: June 2009

Dielectrophoresis (DEP) is the motion of a particle due to polarization effects in nonuniform electric fields. DEP is an electrokinetic transport mechanism that can be used to concentrate and separate particles. DEP is a nondestructive technique, with a great potential for the separation and concentration of bioparticles. Traditionally, DEP has been carried out employing arrays of microelectrodes to generate nonuniform electric fields. This approach is expensive due to the elevated cost of microelectrode fabrication, which makes high throughput systems economically unfeasible. An alternative is the technique called insulator-based DEP (iDEP). In this technique, nonuniform electric fields are created with an array of insulating structures, instead of electrodes. Insulating materials such as plastics have excellent malleability and can be mass replicated, providing for high-throughput and large-volume devices. The present study investigated the effect of bulk medium properties on the dielectrophoretic behavior of microparticles under iDEP, employing microdevices made from glass. Each microdevice contained several microchannels, and each microchannel contained an array of insulating cylindrical posts. Electric field was applied across the post array, creating regions of higher and lower electric field intensity. Prior to each experimental session, the microchannel was filled with a buffer solution of a known pH and conductivity. A sample of the microparticles was injected into the microchannel and an electric field was applied. The dielectrophoretic response of the particles was recorded in the form of videos and pictures. A parametric study was carried out by varying the pH and conductivity of the bulk medium, as well as the magnitude of the applied electric field, in order to study how each one of these parameters affects the dielectrophoretic response of the microparticles. It is anticipated that the results from this research project will provide with guidelines for the design and operation of insulator-based DEP devices for the concentration and separation of bioparticles.
Flow Boiling of Water in Minichannels: Effect of Pressure
Authors: Bang Kwang-Hyun , Hong Kun-Eui , Hwang In-Seon
Published: June 2009

This paper reports an experimental study on flow boiling of water in a minichannel. Flow boiling heat transfer coefficients and pressure drops were measured and the data were compared with existing correlations. The effect of pressure was the major objectives in this study and the range of pressure was 1 to 18 bars. The experimental apparatus consisted mainly of a minichannel test section, gear pump, pre-heater, pressurizer, condenser and evaporator. The evaporator was used for variation of vapor quality at the inlet of test section. The pressurizer controls the desired system pressure. The test section is a round tube of 1.73 mm inside diameter, made of 316 stainless steel. The test section and the evaporator tubes were heated by DC electric current through the tubes. The measured flow boiling heat transfer coefficients showed two distinct regions; relatively high heat transfer coefficients at low vapor quality and lower heat transfer coefficients at higher vapor quality. This observation implies the change of flow regime, slug to annular flow. Comparisons of the experimental data and the prediction of correlations (Gungor & Winterton, 1987; Tran et al., 1996; Kandlikar, 2003) showed large discrepancy in both regions.
Secondary Flow Effects in a Trapizoidal Minichannel Flow System Involving Two Straight Sections Separated by a 180° Bend
Authors: Oosthuizen Patrick H.
Published: June 2009

When the flow in a minichannel passes around a bend, secondary flows can develop which can affect the flow, pressure drop and heat transfer rate in the bend and in the flow upstream and downstream of the bend. In order to investigate these effects in more detail attention has been given to flow in a simple minichannel system in which the flow enters the system with a uniform velocity and temperature and passes through a straight channel that has a length that is 10 times the size of the channel. The flow then passes around a rounded 180° bend. Following the bend, the flow passes down another straight channel which also has a length of 10 times the size of the channel. A uniform heat flux is applied over the entire surface of the channel. The channel has a trapezoidal cross-sectional shape. It has been assumed that the flow is steady and incompressible and that there is no slip at the channel walls. The governing equations have been written in dimensionless form and solved using a commercial finite-element based software package, FIDAP. The solution has the following parameters: the Reynolds number, the Prandtl number, the dimensionless radius of the bend and the ratio of the bottom-to-top widths of the channel. Results will only be presented for a Prandtl number 0.7 for Reynolds numbers of between 10 and 500 for various dimensionless bend radii and various bottom-to-top channel width ratios. The major concern in this work is with the extent of the influence of the secondary flow on the flow in the straight channel sections upstream and downstream of the bend. The effect of the channel shape and of the dimensionless channel corner radius on the pressure distributions and on the dimensionless wall temperature distributions, in the straight channel sections in particular, have been considered.