bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effects of Oil in Circulation on the Performance of an Automotive Air Conditioning System
Authors: Mackenzie Pat T. , Lebbin Paul A. , Eckels Steven J. , Hosni Mohammad H.
Published: March 2009

An automotive air conditioning system was subjected to varying percentages of oil in circulation (OIC) to investigate its impact on the evaporator, the condenser, and cycle performance. Since automotive air conditioning systems do not typically use oil separators, the compressor lubricant circulates through the system and effects evaporator, condenser and cycle performance. The OIC of the system was controlled by means of an oil separator installed in a parallel line at the compressor outlet allowing variable amounts of refrigerant to pass through the separator. The separated oil was returned upstream of the compressor inlet. It was found that the amount of OIC had an impact on the air conditioning system’s performance. The information presented allows the designer to judge the performance merits of installing an oil separator in an actual automotive air conditioning system of the type that was being simulated. The test system was built on a workbench to facilitate installation of various sensors to measure temperatures, pressures, relative humidity, flow rates, and power consumption. The workbench was placed across two environmental chambers such that the environmental conditions at the evaporator and condenser could be independently controlled. A test matrix of varying refrigerant flow rates, air flow rates, environmental conditions, and OIC were designed to simulate a range of car speed conditions that would be encountered in practice. An analysis was performed on the data collected from the workbench and the equations used in that analysis are presented in the paper. Although the results show some increase in heat transfer performance and cycle efficiency the overall improvements were moderate.
Determination of Outside Heating Distribution Using an Inverse Algorithm for an Industry Hydrothermal Autoclave With Three-Dimensional Flows
Authors: Li Hongmin , Braun Minel J. , Wang G.-X. , Evans Edward A.
Published: March 2009

Hydrothermal growth is the industry method of preference to obtain high quality single crystals. Due to the high pressure and high temperature growth conditions, growth process is carried out in closed containers. During a growth run, the only flow and heat transfer that control crystal growers have is the outside heating. An inverse algorithm, used to obtain the heating distribution for an autoclave with a two-dimensional flow, is further developed and used to determine the heating distribution for an industry autoclave with three-dimensional flows. A cross-section area average temperature distribution is set as a target. With the three steps, including CFD simulation of the fluid flow, heat conduction in the metal wall, and heat conduction in the insulation layer, the heater heat flux distribution is determined. The distributions appear close to linear from the median height to the top/bottom with small magnitude deviation in the circumferential direction. Linearly distributed heaters, based on the determined heat flux distribution, are then used and heat transfer and fluid flow is numerically simulated with a conjugate model. The achieved temperature agrees well with the targeted one. The distribution and heating rates of linearly distributed heaters can be applied to industry autoclaves.
Hydrodynamics and Heat Convection From a Disk Facing a Uniform Flow
Authors: Kendoush Abdullah Abbas
Published: March 2009

Exact solutions of the equations of momentum and energy of a circular disk in a uniform incompressible flow directed along its axis of symmetry are obtained. Laminar, irrotational and inviscid flows were assumed. The solutions for the pressure distribution, drag coefficient and convective heat transfer of the disk are presented in explicit forms. Some peculiar fluid-dynamical behavior of the pressure distribution at low and high Reynolds numbers are revealed. The derived equations were agreeable with other numerical and analytical solutions and experimental data.
Research on Developing Propeller Flowmeters With Increased Accuracy
Authors: Gryshanova Iryna , Korobko Ivan
Published: March 2009

This research is devoted to an increase in the accuracy of propeller flowmeters. Achievement of this goal solved a number of problems. These include the following: • development of a detailed multi-parametrical mathematical model that considers many influences; • investigation of propeller flowmeter behavior in the dynamic mode at propeller acceleration from the condition of rest and its sudden retardation; • study of propeller flowmeters in the static mode. The analysis of the influence of physical properties of measured liquids and flowmeter geometrical parameters on the static characteristics; • development of the algorithms and programs of mathematical modeling; • development of the algorithm and program of optimization for design of a propeller flowmeter; • verification of obtained results.
Retraction and Breakup of an Initially Stretched Ligament
Authors: Homma Shunji , Koga Jiro , Matsumoto Shiro , Tryggvason Gre´tar
Published: March 2009

Unsteady motion of an initially stretched ligament in another immiscible fluid is studied numerically for the flow dominated by both inertia and viscosity. Numerical simulations were conducted using an axisymmetric version of a Front-Tracking / Finite Difference code. The ranges of the non-dimensional numbers are: 4.2 × 10−3 < OhD < 4.2 × 10−1 and 10−2 < μˆ < 10, where OhD is the Ohnesorge number based on the ligament (OhD = μD / 2a0ρDσ and μˆ is the viscosity ratio (μˆ = μD/μC). The tip of the ligament retracts due to the non-uniformness of the capillary force, and a bulb forms. Simulation results show that there are two different modes: i) the bulb pinches off and the rest of the ligament also breaks up into drops, and ii) the bulb moves toward the midsection of the ligament and the ligament becomes a spherical drop. The former mode is observed when the retraction takes enough time for capillary waves to grow. The latter mode takes place when the growth of capillary waves is slow relative to the retraction speed.
The Effect of Reynolds Number on the Ventilation Efficiency in a Wind Tunnel
Authors: Li Jun , Yavuz Ibrahim , Celik Ismail B. , Guffey Steven E.
Published: March 2009

The present work is concerned with the effect of the ventilation intensity on the worker exposure in a tunnel when the worker is facing the downstream direction and a gaseous contaminant is released in an arm length of his reach. A three-dimensional model of a manikin which was used in the experiments was created in order to study the effect of the mean inlet velocity which can be characterized by the Reynolds number based on the equivalent diameter of the head of the manikin. For this study, turbulent flow was assumed to enter the ventilation tunnel and exit at the other end from an exhaust duct. The scalar transport method was employed to determine the ethanol vapor concentration field. The results with the low_Re RNG turbulence model are compared to the ones with the RNG turbulence model. The results with the RNG k-ε turbulence model seem to agree better with the experimental data at higher Reynolds numbers. At lower Reynolds numbers there are significant differences between experiments and predictions.
Geometric Parametric Study of a Fan Blade Cascade Using the New Parametric Flow Solver Turb’Opty
Authors: Moreau S. , Aubert S. , Grondin G. , Casalino D.
Published: March 2009

The newly developed parameterized CFD solver Turb’Opty™, based on a Taylor series expansion to high order derivatives of the solutions of the discretized Navier-Stokes equations, has been successfully extended to the geometric parameterization of an engine cooling fan blade cascade. It involves the development of a pre-processor Turb’Mesh™ that smoothly parameterizes the reference grid for the selected three parameters: the stagger angle, the pitch and the chord length. Comparisons with direct Turb’Flow™ CFD results have validated the accuracy of the parameterized solutions obtained by a simple polynomial reconstruction around a reference solution with respect to the three geometric parameters for a first order expansion with respect to each parameter for a variable turbulence. Cross correlation between the pitch and the chord variations have also validated the consistency of the parameterization.
Hands-On Student Experience With Complementary CFD Educational Interface and EFD and Uncertainty Analysis for Introductory Fluid Mechanics
Authors: Stern Fred , Muste Marian , Xing Tao , Yarbrough Donald
Published: March 2009

Development, implementation, and evaluation are described of hands-on student experience with complementary CFD educational interface and EFD and uncertainty analysis (UA) for introductory fluid mechanics course and laboratory at The University of Iowa, as part of a three-year National Science Foundation sponsored Course, Curriculum and Laboratory Improvement - Educational Materials Development project. The CFD educational interface is developed in collaboration with faculty partners from Iowa State, Cornell and Howard universities along with industrial partner FLUENT Inc. and designed to teach CFD methodology and procedures through interactive implementation that automates the “CFD process” following a step-by-step approach. Predefined active options for students’ exercises use a hierarchical system both for introductory and advanced levels and encourages individual investigation and learning. Ideally, transition for students would be easy from advanced level to using FLUENT or other industrial CFD code directly. Generalizations of CFD templates for pipe, nozzle, and airfoil flows facilitate their use at different universities with different applications, conditions, and exercise notes. Complementary EFD laboratories are also developed. Classroom and pre-lab lectures and laboratories teach students EFD methodology and UA procedures following a step-by-step approach, which mirrors the “real-life” EFD process. Students use tabletop and modern facilities such as pipe stands and wind tunnels and modern measurement systems, including pressure transducers, pitot probes, load cells, and computer data acquisition systems (Labview) and data reduction. Students implement EFD UA and use EFD data for validation of CFD and AFD results. Students analyze and relate EFD results to fluid physics and classroom lectures. The laboratories constitute 1 credit hour of a four credit hour 1 semester course and include tabletop kinematic viscosity experiment focusing on UA procedures and pipe and airfoil experiments focusing on complementary EFD and CFD for the same geometries and conditions. The evaluation and research plan (created in collaboration with a third party program evaluation center at the University of Iowa), focuses on exact descriptions of the implementations, especially as experienced by the students. Also discussed are conclusions and future work.
Quantification of Modulated Spray Dynamics by Time-Resolved DPIV
Authors: Chishty Wajid A. , Brady Michael R. , Schiller Noah H. , Vlachos Pavlos P. , Vandsburger Uri
Published: March 2009

This effort presents the application of an experimental high frequency and time-resolved global optical flow diagnostics for the characterization of pulsed spray flows. Such flows are encountered during active control of thermoacoustic instabilities, where high-bandwidth fuel modulation is often utilized to disrupt the combustor acoustic and unsteady heat release coupling. The understanding of spray dynamics is thus of paramount importance for these active control methodologies in order to achieve optimum control authority. A novel time-resolved Digital Particle Image Velocimetry (TRDPIV) implementation is employed for the dynamic investigation of the modulated spray. The method can measure both the droplet velocities as well as the droplet size distribution, from the same recorded images. The method provides planar image based droplet sizing using Mie scattering from DPIV measurements, with >5KHz sampling rate. Thus, eliminating complicated experimental approaches based on interferometer or fluorescence-Mie ratio. This paper presents the results of drop size characterization. Data processing is performed using different particle size evaluation schemes. The results are compared with measurements acquired from Phase Doppler Anemometry (PDA), conducted under same the experimental conditions. Experiments are conducted in non-reacting quiescent conditions, using an industrial simplex nozzle. The proportional spray modulation is obtained using a throttle valve-piezoelectric stack actuation system. The measurements for the current DPIV work are obtained under different pulsing amplitudes and frequencies. The results indicate that time-resolved DPIV can be a valuable tool in investigating dynamic response of modulated sprays.
Novel, Subpixel Resolution Schemes for Particle Image Velocimeters
Authors: Brady Michael R. , Vlachos Pavlos P.
Published: March 2009

Simultaneous velocity and size measurements are of great importance for resolving the dynamics of polydispersed multiphase flows. This effort explores novel sub-resolution particle center estimation algorithms for Digital Particle Image Velocimetry (DPIV) and Particle Tracking Velocimetry (DPTV). In addition these schemes provide direct measurements of the apparent particle image diameter using the same DPIV/DPTV recordings. Three novel fitting schemes were developed and compared with established methods such as center of mass, three-point Gaussian fit estimator and a least-square fit method. The new methods consist of two variations of a four point gaussian estimator and a variation of the conventional least-squares fit estimator. The new methods eliminate the bias error due to pixel discretization, thus significantly reducing the total error in the position and sizing measurement compared to the classic three point and least squares Gaussian estimators. In addition, the accuracy of the least-squares fits were essentially independent of the true particle diameter and significantly reduced the particle position error compared with current estimation schemes.
On the Accuracy of Wall Shear Stress Using DPIV
Authors: Etebari Ali , Carneal Jason , Vlachos Pavlos P.
Published: March 2009

Wall shear stress measurements are important for a variety of fluid mechanics phenomena and engineering applications ranging from estimation of viscous drag to the regulation of endothelial cell function in arterial flows [1–5]. Although DPIV has emerged over the past years as the method of choice for global non-invasive optical flow diagnostics [6–13] the issues associated with the indirect estimation of wall shear stresses from DPIV measured velocities have not been sufficiently addressed. The challenge is even more significant in the presence of deformable and dynamically moving boundaries. In particular such measurements require accurate determination of wall position, near-wall velocity measurements using DPIV algorithms, and the indirect estimation of the velocity derivatives in order to evaluate the shear stress. Dynamically moving boundaries, whether rigid or compliant, require special consideration, as the boundary position must be determined accurately as a function of space and time. It is necessary to quantify the accuracy of each measurement that contributes to the error of the wall shear stress estimation. In this work we decompose the problem into the following three aspects: (a) determination of the exact boundary points (b) DPIV velocity measurement uncertainty in the near wall region. (c) velocity derivative error. Methodologies and improvements addressing each aspect individually are proposed and a systematic parametric study of the related error is performed. To our knowledge, this is the first detailed parametric effort to quantify the errors associated with wall shear stress estimation from DPIV velocities.
A Numerical Study of 2-D Synthetic Jet Formation
Authors: Fugal Spencer R. , Smith Barton L. , Spall Robert E.
Published: March 2009

The formation of a two dimensional synthetic jet is studied numerically by solving the incompressible, unsteady, Reynolds-averaged, Navier-Stokes equations. Results for two exit geometries, a sharp exit and a rounded exit, and several dimensionless stroke lengths are compared. This study focuses on how the exit geometry and dimensionless stroke length change the following parameters: the power required to form the jet, the net momentum flux in the jet downstream of the exit, the formation threshold of the synthetic jet, and the location of the stagnation point during the suction portion of the cycle.
A Learner-Centered Student Course Portfolio
Authors: Narayanan Mysore
Published: March 2009

In this short paper the author tries to explain how a learner-centered student course portfolio has helped him to document the educational outcomes. The author has taught and is currently teaching the subject matter of Hydraulics, Hydrology and Fluid Mechanics at an undergraduate level. Here the author tries to correlate the assessment of student learning to the assessment of instructor teaching methodologies. It is well known that industry is in need of employees that are committed to long-term development and continuous improvement. The key element here is to recognize the fundamental concept that teaching and learning are connected and therefore it is essential that the interaction between the instructor and learner is properly documented in the portfolio. (Cerbin, 1994). While addressing these issues, the author raises five questions: 1. What should be counted as appropriate goals in an undergraduate engineering course that has a significant laboratory component? 2. Are the teaching practices utilized by the instructor in this course providing reasonably acceptable paths toward accomplishing the specified learning goals? 3. What do students actually accomplish in the course and the laboratory exercises and how does the instructor’s teaching methodologies contribute to students’ intellectual development and progress? 4. How does the instructor respond to students’ learning difficulties? Does the teacher revise the teaching strategies to address such problems? 5. What impact does this type of teaching have on students’ life-long learning attitudes? Are they able to “learn, how to learn.” A course portfolio is deemed as a specified document that represents the specific accomplishments of the student and is structured to explain what, how and why the students learnt in that particular course. The portfolio shall include everything that was accomplished in that particular course. It should contain a teaching statement that provides a flow-chart. (Knapper, 1995). Further, an assessment analysis of student learning should be supported by class work, problem sets, quizzes, examinations, research reports, term papers, examinations, laboratory reports, etc. An analysis of student feedback is essential to document teaching effectiveness. Finally, a comprehensive course summary. The summary should describe the strengths and weaknesses of the course in terms of students’ learning. (Richlin, 1995).
A Strategic Planning Process for Implementing and Improving Assessment
Authors: Narayanan Myrose
Published: March 2009

In this paper, the author discusses twelve assessment methods that were successfully utilized by the department of engineering technology at Miami University. Documentation of these assessment techniques helped the department obtain a six-year accreditation by the TAC-ABET commission. The twelve assessment methods described in this paper form a part of strategic planning process that is normally followed in the School of Engineering and Applied Science. The principle is to document how the department keeps tabs on its education commitment. The assessment practices adopted by the department effectively incorporate the feedback received, in a constructive manner. Furthermore, the department has concentrated its efforts on developing a mechanism that primarily focuses on closing the loop, in each of the twelve methods outlined.
Turbulent Reduction in a Wind Tunnel Using Trip Strip
Authors: Soltani Mohammad Reza , Manshadi Mojtaba Dehghan , Mirabdollahi Mohammad Javad
Published: March 2009

In this investigation an intensive experimental study was conducted to study the flow quality in a test section of a low speed, V∞ = 10–100, closed return wind tunnel. An interesting result was obtained when a trip strip, a guitar wire with D = 1.14mm, was installed near the end of the contraction region. Addition of this trip wire resulted in a turbulent reduction almost at all speed ranges along the entire test section. Further, it smoothness the variation of turbulent intensity along the test section too. Velocity profiles along the tunnel wall at various speeds using a rake were measured with and without the trip wire. In addition, pressure contours at different location of the test section was measured too.
An Analytical Technique to Determine the Potential for Moisture Accumulation in Deactivated Structures
Authors: Gordon John R. , Minichan Richard L. , Mullner James A.
Published: March 2009

This paper describes an analytical technique developed to predict an order of magnitude volume of moisture accumulation in massive structures after deactivation. This work was done to support deactivation of a Department of Energy nuclear materials processing facility. The structure is a four-story, concrete building with a rectangular footprint that is approximately 250m long by 37m wide by 22m high. Its walls are 1.2m thick. The building will be supplied with unconditioned ventilation air after deactivation. The objective of the work was to provide a cost effective engineering evaluation to determine if the un-conditioned ventilation air would result in condensate accumulating inside the building under study. The analysis described is a simple representation of a complex problem. The modeling method is discussed in sufficient detail to allow its application to the study of similar structures.
Heat Exchanger Design for the Process Industries
Authors: Bell Kenneth J.
Published: March 2009

The design process for heat exchangers in the process industries and for similar applications in the power and large-scale environmental control industries is described. Because of the variety of substances (frequently multicomponent, of variable and uncertain composition, and changing phase) to be processed under wide ranges of temperatures, pressures, flow rates, chemical compatibility, and fouling propensity, these exchangers are almost always custom-designed and constructed. Many different exchanger configurations are commercially available to meet special conditions, with design procedures of varying degrees of reliability. A general design logic can be applied, with detailed procedures specific to the type of exchanger. The basis of the design process is first a careful and comprehensive specification of the range of conditions to be satisfied, and second, organized use of a fundamentally valid and extrapolatable rating method. The emphasis in choosing a design method is upon rational representation of the physical processes, rather than upon high accuracy. Finally, the resultant design must be vetted in detail by the designer and the process engineer for operability, flexibility, maintainability, and safety.
Flow Structure and Scalar Transport for Jets Impinging on a Rotating Flat Surface
Authors: Papadopoulos George , Hammad Khaled J.
Published: March 2009

The transport of mass and momentum induced by an axisymmetric circular jet impinging on a flat surface has been investigated using a combined PIV/LIF technique. The two techniques were deployed in a water tank that housed two circular flat plates with a centrally located submerged jet issuing normally from one of them. The submerged jet was operated at fixed flow rate conditions, and subjected to a small constant injection of a Rhodamine solution to generate the LIF. Injection of the Rhodamine solution was performed after the water jet had reached hydrodynamic steady state conditions. The jet Reynolds number was varied from the laminar to the moderately turbulent flow regime of a fully developed pipe jet. The influence of rotating the impingement plate was also investigated. The measurements, for a fixed distance of the jet nozzle from the surface, reveal the flow structure and give insight into the transport of mass and momentum as a function of Re and impingement plate rotation.
Development and Analysis of a Fast Temperature Sensor for High Velocity Flows
Authors: Abanteriba Sylvester , Mueller Mark
Published: March 2009

The paper reports on the development of a fast-response sensor for the measurement of stagnation gas temperatures in high speed wind tunnels. This thin-film sensor consists of a combination of two materials: A carrier plate of Zirconium oxide (zirconia, ZrO2) as a substrate material and platinum as the sensing film. After the sensors had been successfully manufactured, tests showed that the response time is approximately 150 ms in the conditions on a smaller test rig. Applications for this sensor include the use in high speed wind tunnels, if the required response times are in the range of several hundredths of a second, or measurements are undertaken in a high temperature environment.
Advanced Zero Head Propulsion in Review
Authors: Bayandor Javid
Published: March 2009

This paper reviews the recently introduced concept of unsteady zero-head propulsion (HYPS©) and its particular attributes offering to revolutionize the conventional turbomachinery and fluid power technologies. The paper continues by underlining some of the fundamentals of the advanced concept that enable the system, in a unique way, to highly efficiently exploit the energy of turbulent and chaotic fluid flows. Extensive simulations and trial runs have highlighted the potential of the system in dealing with shortcomings of the traditional systems when encountered by random and multi-directional upstream flow conditions.
Remediation of the Southern Storage Area (SSA)
Authors: Atyeo Paul
Published: March 2009

This large scale radioactive and chemical land remediation project is a recent example of UKAEA delivering safe and cost effective restoration of a nuclear legacy. The SSA was a 7-hectare part of the non-nuclear licensed area at Harwell, Oxfordshire. The Harwell site is steadily being redeveloped as a business centre. Restoration of the SSA was linked to an opportunity to develop adjacent land for new residential housing. The SSA shared a boundary with Chilton County Primary School and the remediation project had high stakeholder interest. The RAF used the SSA as an ammunition store until 1945. UKAEA used the site from 1946 for radioactive waste handling and for the burial of chemical, radioactive and beryllium contaminated wastes. Planning, characterisation and decommissioning has been ongoing since the late 1980’s. Over the last two years a final clean-up operation has been completed. The project was managed by UKAEA and implemented through competitive contract by RWE Nukem and VHE Construction. The clean-up utilised stakeholder management and consultation methods to inform regulators and the local community. This included a formal public consultation concerning remedial options and the potential for environmental impact. The clean-up was designed against site specific risk based radionuclide and chemical clean-up targets. The project involved the survey, assay and clearance of 250,000 m3 of soils resulting in the segregation of 18,000 m3 of general, chemical and exempt radioactive wastes. The SSA landfill pits were excavated inside double ventilated containment tents in order to ensure that emissions from the works did not affect the nearby public. The project has successfully restored the site to a condition suitable for unrestricted public access.
Managing Nuclear Liabilities in the UK: Evaluating Strategic Options and Communicating Financial and Resource Implications
Authors: Harper A. , Harrison J. , Swan D. N.
Published: March 2009

Decisions on the strategies to follow in dealing with these operational and decommissioning wastes require consideration of a wide range of issues including environmental impact, safety, stakeholder acceptability, cost and practicability. In this paper, we focus on an approach that we have developed to analyse the time-varying resource requirements of different waste management options in terms of cost and plant capacity. The approach addresses the need for: • a standardised approach that can be used across different organisations; • a range of standard graphical outputs that can be used to communicate the key issues; • the need to match waste management strategy with the potential availability of relevant plant and facilities; • the need to evaluate the risks that arise to any strategy as the result of changes in policy or the failure of some component of the strategy. Many of the required issues can be addressed using a simple spreadsheet approach. However, this does not provide for standardisation, auditability or transparency and does not provide a wide range of analysis and presentation tools. We therefore advocate the use of a specifically designed decision support tool. ALPS (Advanced Liabilities Planning System) has been developed over a number of years to meet these requirements. It has been developed around the database package ACCESSTM and runs on Pentium TM PCs but has the essential features of project management packages that are necessary for strategic planning. The principal outputs of the system are cost, timing and utilisation data for waste stores, processing facilities, transport and disposal operations. The outputs can be displayed at any level of aggregation to allow the effects of different scenarios to be evaluated.
Modelling the Gas Generation of Intermediate and Low Level Radioactive Wastes
Authors: Bracke G. , Mu¨ller W.
Published: March 2009

Gas generation is a safety issue for repositories for radioactive waste because of its potential impact on barrier integrity and radionuclide transport. Therefore, the amount of gas that might be produced and the generation rate has to be assessed. For a qualified prediction of the gas generation potential and rates under repository conditions for radiolysis, corrosion and microbial degradation, gas generation rates concerning real waste packages, laboratory experiments as well as natural analogues for microbial degradation have been evaluated. These data were applied to long-term modelling of gas generation at two sites. The modelling includes aerobic, anaerobic, dry and saturated phases and variations of pH depending on the degradation of cement in order to assess the range of gas generation rates. The results show very low gas generation by radiolysis. At one site, radiolytic gas generation was dominated by short-lived nuclides. The other site had a larger inventory of long-lived radionuclides, yielding higher long-term radiolytic gas generation. In contrast to previous calculations, the gas generation potential by microbial degradation was significantly lower than calculated by stoechiometry. The microbial gas generation potential is reduced by microbial degradation before closure of the site. Furthermore a saturation effect, known from natural analogues, waste dumps and experiments, was modelled, resulting in a significantly lower yield of gas. Overall, the gas generation potential and rate were dominated by corrosion processes of iron.
Assessment of Package Performance During Long-Term Storage of Intermediate-Level Radioactive Waste
Authors: Chambers A. V. , Rodwell W. R. , Kelly M. , Hoch A. R. , Baker A. J.
Published: March 2009

In the UK, the need for the long-term management of intermediate-level radioactive wastes arises from the absence of an established deep disposal option. As a consequence there is a requirement to demonstrate the ‘passive safety’ of waste packages in stores over a necessarily lengthy period (perhaps 150 years or more). ‘Passive safety’ is taken here to imply that the waste packages themselves would remain safe without intervention; it is assumed however, that the store building and associated infrastructure would need to be actively maintained and that the store may need to be ventilated. Importantly, methods for waste storage also need to ensure that possible future options for disposal are not foreclosed. An extended period of storage suggests that emphasis will need to be placed by waste producers on understanding a number of issues such as: • the impact of corrosion on container integrity; • the assessment of container vents and other features as a pathway for the release of radioactivity; • the extent to which wastes are conditioned for storage and the selection of appropriate methods; • the generation and behaviour of toxic or flammable gases in the storage facility; and the mitigating steps that might be needed to address adverse impacts (e.g. the type of ventilation that the store requires). In this paper, we review the requirements and current state of knowledge relevant to the assessment of operational releases of radioactive, flammable and toxic gases from wastes in long-term interim storage.
An Environmental Response Handbook for BNFL Sites
Authors: Claxton David
Published: March 2009

The BNFL Group of Companies owns and operates a number of nuclear licensed sites worldwide. These cover fuel manufacture and reactor services, power reactors, spent fuel management, and nuclear decommissioning and clean-up. To implement its environmental policy, BNFL needs to have tools and techniques to permit it to respond appropriately to Environmental Trigger Events (ETEs). Similarly, BNFL needs to provide assurance that it is able to manage contaminated land in the short to medium term (prior to site closure) — although such tools/techniques could also be used afterward. To meet this challenge, BNFL has developed the Environmental Response Handbook (ERH), with the main themes of: • Global considerations for remediation on an operational site; • Detailed consideration of the application of remediation to the current ETE; • A maintained ‘toolkit’ of favoured remediation techniques; and • Case studies and action plans. The history of development of the ERH was presented at the Waste Management ’02 Conference. This paper builds on this previously presented information. It details the structure and operation of the ERH with reference to a case study. The case study is used to demonstrate how the ERH would be applied in practice.
Optimization Features in Management of Salaspils Research Reactor Decommissioning Waste
Authors: Dreimanis A.
Published: March 2009

Management of decommissioning waste is considered as complex task of seeking for optimal solution in the environment of various competing technical, safety and socio-economical factors. If from the formal mathematics viewpoint it is a multi-parameter optimization task, then for real conditions simplified approach for such problem should be applied. We propose to decompose this task into the set of optimization analysis for particular steps, and then in each step it is easier to find optimum. For the real case of management of radioactive waste arising from dismantling and decommissioning of Salaspils Research Reactor (SRR) we consider following main optimization steps: 1) the choice of the decommissioning concept — among three elaborated versions — with estimation of the foreseen radioactive waste amount for disposal, recycling and free release, taking into account also potential exposures and financial resources; 2) establishment of national radioactive waste management agency “RAPA” Ltd., ensuring common administration and maintenance of the shutdown SRR and radioactive waste (RW) disposal site — RAPA manages some decommissioning activities of SRR and shall actively participate together with envisaged decommissioning operator in this process also in future, but in all stages will keep full responsibility of waste management; 3) optimization of radioactive waste transportation: i) organizational aspects (packing, transportation time, schedule, route, etc.), ii) environmental safety control; 4) optimization arrangement of space for radioactive waste disposal: i) choice of the best strategy to ensure a new space, ii) optimization of the vault size — to be able accommodate decommissioning waste without being oversized; 5) strategy of treatment, conditioning and packing of solid decommissioning waste; 6) optimization of liquid decommissioning waste management — its conditioning together with the solid radioactive waste; 7) socio-economical optimization features: i) existing infrastructure for RW disposal, ii) financial compensation for local municipality, iii) international cooperation, technical and financial assistance by EU, IAEA, Sweden. The proposed optimization features used in the developing of Concept for radioactive waste management in Latvia for the period 2003–2010 (which corresponds to the approved decommissioning period of SRR) supplement existing separate optimization aspects of decommissioning waste management and could be considered as simplified integral set of factors for elaboration of optimal strategy for decommissioning waste management.
Mailuu-Suu Tailings Problems and Options for Remediation
Authors: Vandenhove Hildegarde , Clerc Jean Jacques , Quarch Holger , Aitkulov Abdilamit , Savosin Maxim , Torgoev Isakbek , Mirzachev Muradil
Published: March 2009

The area of the town of Mailuu Suu, Kyrgyzstan, is polluted by radionuclides and heavy metals in tailing dumps and heaps resulting from the historic exploitation of U-mines in the Mailuu Suu area in Kyrgyzstan. Radioactive substances are stored in 23 tailings and 13 mining debris heaps situated along the Mailuu Suu River. The objective of the EC-TACIS funded project is to evaluate and prepare measures to be taken by the authorities to reduce the radiological exposure of the population and to prevent environmental pollution by radionuclides and heavy metals in case of loss of tightness of dams and damage to dumps and heaps from mining and milling by land and mudslides and to propose sustainable remedial options, accepted by the public. The actual radiological situation is of no immediate concern for most of the population of Mailuu Suu. From the gamma radiation monitoring campaign (monitoring network in Mailuu Suu, Kara Agach and vicinity), it showed that the background radiation is 100–120 nSv/h. On the tailings radiation is on average twice background. The average outside and in-house radon concentration is 175 Bq/m3. In 3 of the houses monitored at Kara Agach the radon level is between the exemption limit for new (200 Bq/m3) and old (400 Bq/m3) houses. The concentration of uranium in the Mailuu Suu river water is far below the exemption limit for drinking water set in Kyrgyzstan. Additional dose from irrigation with Mailuu Suu river water is small in actual conditions (< 0.1 mSv/year). However, there is an important possibility that triggered by an eathquake or a landslide, (part of the) tailing(s) content may be directed to the river Mailuu Suu. Doses to the affected population may increase to multiple ten mSv per annum. Given the actual limited stability of Tailing N°3, the potental of such a disaster to occur isnon-neglegible. To impede the consequences of a potential disaster, under the TACIS project different remedial options are evaluated for Tailing 3 including in situ stabilisation and tailing translocation. Also more global remedial options for the Mailuu Suu River valley are studied (translocation of other tailings, tunnel to deviate river, partial protection of river from landslide blockage). It was proposed to acquire a phased approach in time performing urgent limited stabilisation options for Tailing 3, improve the stability of the Tailing 3 by COLMIX-columns in the medium term, while investigating and evaluating further two long-term remedial options: the translocation of the tailings and the long-right-bank river diversion tunnel.
Thermochemical Conditioning of Radioactive Waste: Structure and Properties of Final Processed Product
Authors: Karlina Olga K. , Varlakova Galina A. , Dmitriev Sergei A. , Ojovan Michael I. , Poluektov Valery V. , Petrov Vladislav A.
Published: March 2009

Thermochemical processing method is based on utilization of energy of chemical reactions between components of special exothermic mixtures (termed heat base) to melt radioactive waste and form a vitreous melt after cooling of which a durable monolith product is formed in which radionuclides are fixed. Compositions were studied, structure and properties of final products of thermochemical treatment of ash residue from incineration of solid radioactive waste, spent inorganic ion exchangers (e.g. clinoptililite and silica gel), contaminated clay and sand-based soils, Investigations showed that matrix material is dominantly amorphous and on compliesis to basic requirements to solidified radioactive wast of medium level of activity.
Retention Properties of Carbide-Corundum Ceramics Containing Carbon-14, Caesium-137, and Strontium-90
Authors: Dmitriev Serge A. , Karlina Olga K. , Klimov Vsevolod L. , Ojovan Micheal I. , Pavlova Galina Yu. , Yurchenko Andrew Yu.
Published: March 2009

The system C–Al–TiO2 is of considerable interest for the processing of irradiated reactor graphite waste with the retention of biologic hazardous carbon-14. Investigations of this system were conducted both theoretically and experimentally. Previously, the thermodynamic calculations of the phase composition of resulting end product were performed for a wide variety of components content in the system being investigated. These simulation results have been supported by XRD-analysis of produced specimens. The experimental processing of reactor graphite was conducted by the use of self-sustaining reactions in C–Al–TiO2 mixtures. A search of modifier additives was performed to perfect end product properties. Test specimens were produced by mass ranging from 0.2 to 3 kg in the argon atmosphere. Various techniques were applied to characterize the produced specimens. The compressive strength of specimens of doped carbide-corundum matrices synthesized ranged from 7 to 18 MPa. The carry over of Cs-137 and Sr-90 during synthesis reaction was about 3% wt. The leachability attained of Cs-137 and Sr-90 from specimens was around 10−5 g/(cm2.day). The carbon-14 is combined in the end product in chemically and thermic stable titanium carbide. The carry-over of the carbon combined in carbon monoxide from the reacting mixtures during exothermic process was less than 1% wt. This corresponds roughly to up 0.01% wt. of the carbon-14 inventory, which can be present in the irradiated reactor graphite.
Applying UKAEA’s Data Management and Geographical Information System to the Development of a Safety Case for Contaminated Land
Authors: Pearl Mike , Coppins Gavin , Dennis Frank
Published: March 2009

This paper discusses the application of the UKAEA’s information management and geographical evaluation system (IMAGES) to the development of a safety case for contaminated land on the Dounreay nuclear licensed site. IMAGES is the subject of a separate paper in these conference proceedings: “A Data Management and Geographical Information System (GIS) for the Management of Land Quality on UKAEA Sites” [1]. Nuclear safety on licensed sites in the UK is enforced through the Health and Safety Executive’s Nuclear Installations Inspectorate (NII). Nuclear site licenses contain a number of conditions and it is against the enforcement of these conditions that the NII regulates nuclear safety. Recent guidance issued by the NII to it’s inspectors and it’s licensees covers managing radioactively contaminated land. The NII treats radioactively contaminated land as an accumulation of radioactive waste. It therefore requires licensees to control or contain the material, to record the amount and location of the material and to justify and demonstrate the adequacy of the arrangements to maintain safety by means of a safety case. The IMAGES system has played a key role in developing the safety case for contaminated land and in the on-going management of contaminated land at Dounreay. This paper explains how IMAGES has been used to support Dounreay’s contaminated land safety case by: • recording areas of contaminated land, its activity and its volume; • supporting the conceptual model via 2D and 3D visualisation; • calculating an estimate of the overall inventory of contaminated land at Dounreay (concentrations and volume), and providing output to a risk assessment; • providing project managers with data, which is pertinent to health and safety, for excavations in areas of contaminated land. In addition, providing estimates of waste arisings as a consequence of the proposed excavations; • assisting in controlling activities in areas of contamination (via excavation procedures); • providing a tracking system for wastes excavated from areas of contamination; and • providing the definitive, up to date records with respect to the assessment of land quality status.
Radiolytic Modelling Intercomparison Exercise: Influence of Alpha Radiation on Spent Fuel Alteration Process
Authors: Quin˜ones Javier , Merino Juan , Cera Esther , Bruno Jordi , Cobos Joaquin , Marti´nez-Esparza Aurora
Published: March 2009

Radiolytic models have been usually considered useful tools for studying the behaviour of complex chemical systems under the presence of a radiation field. However, they still don’t have a wider acceptance due to limited availability of kinetic data, difficulty to handle heterogeneous systems, and a lack of model validation. We carry out an intercomparison exercise between two kinetic codes, “Chemsimul” and “Maksima”. The objective of the work is to model the influence of an alpha radiation field in the spent fuel alteration process under repository conditions. The experimental system to be modelled is the dissolution of UO2 α-doped pellets under initial anoxic conditions. These experiments have been carried out under well-controlled conditions, and good quality data are available to us for this purpose. The uranium concentration in solution will be predicted by considering the presence of an α-radiation field and its influence due to radiolysis of water on the pellet surface oxidation and subsequent dissolution. In this paper, a kinetic model for the alpha doped pellet under these conditions is presented. Both codes use the same initial fixed parameters in order to reproduce the pellet alteration process: system geometry, chemical composition of the solution, physicochemical characteristics of the solute and the oxidation conditions of the pellet surface (expressed in terms of U(VI)/U(IV) ratio). The last one is the key parameter in the model for simulating the initial quick dissolution process. The differences in the input data are related to intrinsic restrictions of each code. A review of the differences and the capacities of both codes is also included. The predictions obtained using the two codes are compared and the results obtained are in good agreement, having a small difference related to the way of solving the differential equations by each code. However, this difference is not considered to be of significance when comparing modelled and experimental data, leading to the conclusion that both codes can confidently be used in the radiolytic modelling of this kind of systems.