bluuebunny/crossref_metadata_2025 huggingface dataset:
DTI Nuclear Legacy Programme: Andreeva Bay
Authors: Smith-Briggs Jane
Published: March 2009

Andreeva Bay is located in the Zapadnaya sea inlet at the extreme North-West of the Kola Peninsula (Russian Federation), about 40km from the Norwegian border. It is rather inaccessible, except by sea and the nearest town with facilities for Western visitors is Murmansk some 80km to the SE. Spent nuclear fuel (SNF) was initially stored in two large pools within building 5, however after serious leaks the fuel was transferred to an external “drystore” constructed by adapting three existing concrete tanks, previously allocated for the storage of liquid radwaste. There are currently approximately 20,000 spent fuel assemblies (SFA) stored within the three tanks. The storage conditions of the assemblies are less than adequate, the steel canisters used to store the assemblies are in poor condition and their standard of manufacture was not good. Shielding is locally inadequate and the concrete roof segments are ill fitting with snowmelt known to enter the tanks. Building 5 still contains some fuel fragments that could not readily be moved. The remaining water and structure remain highly active and this included some 4000Ci in sludge and debris at the bottom of the pool. The UK has agreed to support activities to improve the conditions at Andreeva Bay, with respect to SNF management, and DTI (Department of Trade and Industry) have appointed RWE NUKEM as their project management consultants for their Nuclear Legacy Programme in North-West Russia. A number of projects have been identified by the Russian Federation Ministry of Atomic Energy, MINATOM, and these are currently in the project definition stage. These include the characterisation of Building 5, an options study for SNF management at the site, and the construction of a cover for Tank 3a. This paper will describe the current conditions with respect to spent nuclear fuel at Andreeva bay and will discuss the proposed projects under consideration for funding by DTI.
Technology Safety Data Sheets: Tools Perceived as Valuable by Workers, Technology Developers, and Regulators
Authors: Lippy Bruce
Published: March 2009

Several U.S. agencies, most notably the Department of Energy (DOE), have been developing a new information tool for workers to alert them to the hazards posed by operating and maintaining innovative remediation technologies for cleaning hazardous waste. Technology Safety Data Sheets (TSDSs), designed as corollaries to Material Safety Data Sheets, have never been evaluated prior to this research. Three populations were evaluated. DOE technology developers (n = 80) were sent one of four randomly selected TSDSs, along with a Likert-scale, pre-tested questionnaire in the mail. Sixty-two percent responded. Nearly three-quarters agreed that the TSDS format is valuable. Two-thirds agreed that TSDSs would prove valuable for training workers at a hazardous waste site, although there was no consistency in their perception of the long-term benefits of TSDSs. A focus group of state environmental regulators was held through the Southern States Energy Board. The regulators did not have access to safety and health professionals within their state organization, so they agreed that the document would be valuable. They saw TSDSs as facilitating the process of writing permits for new technologies as well as disseminating information to the community near hazard waste sites. The third population, heavy equipment operators who are trained to work with hazardous waste, were also sent one of the same four random TSDs and a questionnaire. From mailing of 935, 475 responded, a 50% return. The workers were more enthusiastic than developers about the value of these document (91% agreed TSDSs were valuable). Eighty-three percent agreed that the similarity to MSDSs increase the ease of use. Risk ratings were considered a valuable element by all three populations. The findings supported the DOE efforts to disseminate safety information through this tool. Examples of TSDSs are available at http://www.iuoeiettc.org.
Engaging the Public on Technical Issues
Authors: Breen Brendan , Atherton Elizabeth , Barlow Steve
Published: March 2009

United Kingdom Nirex Limited (Nirex) is responsible for providing the UK with environmentally-sound and publicly-acceptable options for the long-term management of radioactive materials generated by the Nation’s commercial, medical, research and defence activities. An important part of Nirex’s responsibilities in developing these options is to build acceptance of its concepts through effective dialogue and engagement with a wide range of stakeholders. One of the options developed by Nirex for the long-term isolation of intermediate-level and some low-level from the accessible environment is to place these wastes in a deep underground repository, excavated in stable rock formations. The repository would remain accessible to allow future generations to have the choice of continuing to store the waste, or to dispose of the wastes by sealing and closing the repository. In conducting the scientific and technical research on this phased disposal concept, Nirex wanted its work programmes to take account of any public concerns with regard to radioactive waste and its management and proposed to develop its understanding of such concerns through public engagement. In October 2001, Nirex engaged an independent organisation to conduct a series of focus group discussions. Focus group meetings were arranged in 4 locations across the UK, selecting varying groups in terms of age, lifestage and socio-economic circumstances in order to engage a broad cross-section of the UK population. Each group attended two, 2-hour sessions on successive evenings. The first session was a general discussion of the issues of nuclear energy and radioactive waste. The second session focused on the more specific detail of the Nirex Phased Disposal Concept. Explanatory material was given to participants at each session. The work has provided some very useful information on issues, which the focus groups considered significant. The groups were able, in the short time available, to grasp many important issues and to provide their views across a range of technical areas. This work has helped Nirex to better understand ways of engaging the public in technical issues and to appreciate some of the key areas and concerns on the more technical areas associated with phased disposal. Several technical queries were identified, which the facilitators were unable to answer during the focus group discussions — Nirex has subsequently provided answers to these questions and made these available on the Nirex Bibliography. This paper describes the approach taken for the focus groups and outlines key findings from the work and some implications for Nirex in communicating technical issues to the public.
Management of Institutional Radioactive Waste in Lithuania
Authors: Poskas P. , Adomaitis J. E. , Kilda R.
Published: March 2009

The growing number of radionuclide applications in Lithuania is mirrored by increasing demands for efficient management of the associated radioactive waste. For the effective control of radioactive sources a national authorization system based on the international requirements and recommendations was introduced, which also includes keeping and maintaining the State Register of Sources of lonising Radiation and Occupational Exposure. The principal aim of the Lithuania’s Radioactive Waste Management Agency is to manage and dispose all radioactive waste transferred to it. Radioactive waste generated during the use of sources in non-power applications are managed according to the basic radioactive waste management principles and requirements set out in the Lithuanian legislation and regulations. The spent sealed sources and other institutional waste are transported to the storage facilities at Ignalina NPP. About 35,000 spent sealed sources in about 500 packages are expected until year 2010 at Ignalina NPP storage facilities. The existing disposal facility for radioactive waste from research, medicine and industry at Maisiagala was built in the early 1960’s according to a concept typical of those applied in the former Soviet Union at that time. SKB (Sweden) with participation of Lithuanian Energy Institute has performed assessment of the long-term safety of the existing facility. It was shown that the existing facility does not provide safe long-term storage of the waste already disposed in the facility. Two alternatives were defined to remedy the situation. A first alternative is the construction of a surface barrier and a second one is a retrieval solution, whereby the already stored waste will be retrieved for conditioning, characterisation and interim storage at Ignalina NPP. Facilities for the processing of the institutional radioactive waste are required before submittal to Ignalina NPP for storage, since the present facilities are inadequate. Feasibility study to establish a new central facility has been performed by SKB International Consultants (Sweden) with participation of Lithuanian Energy Institute. This study has identified the process applied and equipment needed for a new facility. Reference design and Preliminary Safety Assessment have also been performed. Plans for the interim storage and disposal of the institutional waste are described in the paper. The aspects of finging safe disposal solutions for spent sealed sources in a near surface repositories are also discussed.
Quantification of Transferring and Adhering for Pd, Mo, Te, Sb, Ru, Re, Cs and I During the Evaporation Under Vacuum and at Atmospheric Pressure
Authors: Ito K. , Takata T. , Kamiya M.
Published: March 2009

In order to modify current nuclear fuel reprocessing plants on the basis of a more sophisticated, economical, and safer nuclear waste recycling system, the production of low-level radioactive wastes must be reduced and the recycling of wastes must become more efficient. To simulate liquid waste recycling operations, evaporators under vacuum and at atmospheric pressure were used to determine adhering and transferring rates for Pd, Mo, Te, Sb, Ru, Re, Cs and I in the nitric acid and sodium nitrate solutions. In the evaporation from the HNO3 and NaNO3 solutions containing precipitate PdI2, the percentage values for materials adhering on the inside of lid at vacuum pressure were 0.01 ∼ 0.1%/m2, however at atmospheric pressure the values were 0.001 ∼ 0.01%/m2. Adhering percentage values on the condenser were 0.0001 ∼ 0.001%/m2 for the vacuum and atmospheric pressure systems. The transferred percentages into the distillate for Pd, Mo, Te, Sb, Ru, Re, and Cs were 0.0001 ∼ 0.001% in the HNO3 and NaNO3 solutions for the vacuum and atmospheric pressure systems, and those of I were about 10% for HNO3 system at atmospheric pressure, 2∼7% for HNO3 system under vacuum, 0.01∼0.1% for NaNO3 system under vacuum. Reducing rates for the treated solution were one third of feeding solutions in the evaporation under vacuum and at atmospheric pressure.
Corporate Social Responsibility (CSR) and UK Nirex Limited
Authors: Tibballs Sue , Dalton John , Wild David
Published: March 2009

In recent years, Nirex has been engaged in a fundamental review of its values, objectives and behaviours. The significant shift to emerge from this review has been a commitment to being a responsible organisation. On both ethical and strategic grounds, Nirex believes it will only have a useful role to play in future radioactive waste management debates if it can show that it is a socially responsive and accountable organisation. Important commitments have already been made, and policies introduced, including a Transparency Policy, and an Environmental Policy. Over the same period, there has been a growing discourse and engagement in the UK with Corporate Social Responsibility (CSR). A wealth of organisations and consultants have emerged offering thought leadership and support in this area, some of whom have approached Nirex offering services. The challenge Nirex faces, however, is to understand what relevance and implications the CSR debate has for its work, and its wider commitment to responsibility. Should Nirex have a CSR strategy and produce a CSR report, or does ‘responsibility’ mean something different to Nirex? What would engaging in CSR mean — is there a danger that being responsible would become a stand-alone activity in the organisation, rather than a ‘mainstreamed’ commitment? If Nirex were to produce a CSR report, who would it be aimed at, and how would it fit alongside other corporate communications? In order to help answer these questions, and to develop a clear position and strategy, Nirex asked the Future Foundation to help facilitate input from consultants and other practitioners who have relevant experience. This paper will describe what was undertaken, the results and some thoughts on what this means for the future.
Management System for D&D Waste: ReVK
Authors: Gru¨ndler Detlef , Kaffka Elke , Wurtinger Wolfgang
Published: March 2009

Present German decommissioning projects, such as NPP Greifswald, NPP Rheinsberg, NPP Wu¨rgassen, Siemens Fuel Fabrication and Siemens Hot Cells, utilise an uniformed management system for registration, tracking, monitoring and managing of radioactive materials. This management system, the ReVK (German acronym: ReVK = Reststofffluss-Verfolgungs- und Kontrollsystem), is designed to track the complete disposal treatment of radioactive waste beginning from its generation with all disposal and conditioning steps up to its final destination. ReVK is built on a standardised base version, which offers multiple configuration options with respect to individual the user-specific requirements concerning the basis functionalities of ReVK. In particular ReVK was designed to: • register, actualise and provide information about radioactive substances and wastes. • control and manage all shipment, storage and treatment processes. • manage substantial balances and bookkeeping requirements. • process checks for exemption and the suitability for a final disposal. • prove the destination of radioactive waste and substances resulting from the decommissioning process. • generate official reports and documents. • support operational issues resulting from decommissioning and disposal strategy. Furthermore ReVK provides a multitude of add-ons to meet special user needs, which enlarge the spectrum of application enormously. Principally ReVK is designed to be upgraded easily at any time. ReVK is validated and qualified, accepted by experts and authorities and fulfils the requirements for a radioactive waste documentation system.
Design of a Storage Facility for Intermediate Level Waste at Hunterston “A” Decommissioning Site
Authors: Carr A. , Clarke M. J. , Langley G. E. , Sanders N. C. , Sunman C. R. J.
Published: March 2009

Hunterston A Power Station Decommissioning Site (UK) is required to process and store on-site over 2500m3 of raw Intermediate Level Waste (ILW), conditioned into some 1500 packages until a National Repository becomes available. The waste has arisen mainly from irradiated fuel management throughout the operating life of the station and consists of graphite, metal, sludges and resins. Prior to storage the wastes will be recovered from various locations on the site, stabilised and packaged in a passive form suitable for ultimate disposal. The store will comprise a single concrete above ground vault structure serviced by a Package Handling Machine (PHM) and designed for an operating life in excess of 100 years with minimum through life maintenance. The store is intended to be a replicable solution suitable, with only minor modifications, for ILW storage on other decommissioning or operating sites. The paper describes the development of the concept design of the ILW Store up to and including the Preliminary Safety Report (PSR), supported by a Basis of Design. The paper also describes the commercial approach adopted to develop the store design and subsequently construct and commission the store. The factors affecting the design of the store incorporate the formal guidance provided by the Nuclear Installations Inspectorate (NII) [0], and take account of the requirements of the Scottish Environmental Protection Agency (SEPA), the Environment Agency (EA) together with the Local Planning Authorities. The safety assessment addressed factors such as the initial unmitigated consequences, Hazops, safestore safety criteria, passive safety principles and safety functional requirements. Key issues in the safety assessment were dominated by the passive nature of the packages and addressed the recovery requirements for the PHM in the event of failure, the definition of the seismic integrity requirements and the recovery and inspection principles for packages during storage. The generation and selection of options formed a significant part of the work and incorporated support from all disciplines needed for the Design, Construction and Operation of an ILW Store. Further significant areas affecting the design were the stability of stacked packages, provision of a suitable environment for package storage and the interface with the package delivery transporter and projects supplying the waste packages. BNFL has successfully developed a “fit for purpose” ILW Store design primarily for Hunterston A Decommissioning Site, with a high degree of confidence that this design could be adapted to any UK Site.
Clearance Levels in Germany and Their Application in D&D Projects
Authors: Weil Leopold
Published: March 2009

Clearance is an essential part of material management especially in decommissioning of nuclear installations in Germany. Therefore, a system of clearance options has been put in place which provides waste producers with a number of ways to release the material (metal scrap, building rubble, buildings, sites) from regulatory control. There is a tiered system of clearance levels (one set for each clearance option) which generally increase from the unconditional clearance to clearance for disposal only. Under German law, there are only two options for material management: clearance or disposal as radioactive waste in a (planned) deep geological repository. Because of the vast difference in costs, the material is brought to clearance to the greatest extent possible. The application of the new clearance regulations of the Radiation Protection Ordinance (RPO) of 2001 in actual German D&D projects is well under way. Nuclear power plants which are currently undergoing decommissioning (e.g. KWW at Wu¨rgassen, KMK at Mu¨lheim-Ka¨rlich) or which will enter decommissioning soon (e.g. KKS at Stade) have already applied or will apply these clearance regulations. This also pertains to ongoing decommissioning projects (e.g. KGR at Greifswald) which are seeking a change from their old regulations. One of the main reasons is that the new system offers considerable flexibility and extended possibilities to optimise the material management. Application of the clearance levels requires some additional provisions like averaging mass and averaging surface area, a summation rule for cases where more than one radionuclide is present, and a cut-off criterion of 10% total dose contribution for those radionuclides which have very small activities or which are radiologically irrelevant.
An Update on Clearance Initiatives in the United States
Authors: Devgun Jas , Peterson Harold , Trottier Cheryl
Published: March 2009

A number of initiatives have been underway in the United States in the past several years in the area of clearance of solid materials both at the federal level and at the industry and professional society level. Clearance of solid materials is an issue that has significant economic consequences for decommissioning projects where large quantities of such materials are generated. The cost of treating these materials as low-level radioactive waste (LLW) is prohibitive. A regulatory mechanism could remove economic burdens on such projects while maintaining the public health and safety standards. At the federal level major initiatives are being undertaken by the U.S. Nuclear Regulatory Commission (NRC) and the U.S. Department of Energy (DOE). The U.S. Environmental Protection Agency (EPA) has also taken some steps in this area under their Clean Materials Program. In the private sector, the nuclear industry is active through the Nuclear Energy Institute (NEI). The Health Physics Society (HPS) prepared the ANSI/HPS N13.12 standard about four years ago, which has been approved by the American National Standards Institute (ANSI). The American Nuclear Society (ANS) has recently released a Position Statement on the clearance of licensed materials from nuclear sites and the Society has been active in the national deliberations on this subject. The National Academies (NA) conducted a study for the NRC on alternatives for controlling the release of solid materials and their report was issued in 2002. The steel and concrete industries have also participated in the NRC rulemaking process and are opposed to any release standards for materials that may have residual radioactivity on them. This was clear from industry representatives at the stakeholder workshops conducted by the NRC as a part of the enhanced rulemaking effort. A review of all these initiatives shows the intensity of the debate but it also highlights the need for one national standard, preferably dose based, thus allowing site-specific application through derived radioactivity limits. Thus, interagency cooperation and agreement are necessary at the federal level. Consensus is necessary with standard writing organizations, professional societies, public and other stakeholders. This paper provides an overview of the developments in the United States in the area of clearance of solid materials, a brief comparison to international activities, and a discussion of key points for consensus building that is necessary for any initiative to succeed.
Recycling of Metallic Waste Produced During the Decommissioning of Vandellos 1 NPP
Authors: Rodri´guez M.
Published: March 2009

The decommissioning of a Nuclear Power Plant leads to the generation of a high volume of metallic waste, of which a large quantity can be recycled, after separating it from radioactive metal. The methodology that allows to separate radioactive metal from non-radioactive metal is an essential part of Decommissioning, and it requires complex equipment, procedures and controls, both inside Enresa and external (Regulatory Body). After undergoing these controls, most of the metallic material is sent to recycling facilities, where it is mixed with a much larger proportion of metal coming from conventional scrap yards, both here in Spain and abroad. In recent years, there have been a few incidents in melting plants, due to the presence of undetected radioactive material among certain batches of scrap metal. In order to tackle the public concern associated with potential risk, a series of measures have been designed to prevent these incidents or minimise their effects, should they occur. The following presentation will first describe the Spanish protocol established by different national institutions to prevent the presence of radioactive waste among the raw material for recycling, should this occur detect and control it, and secondly the methodology that guarantees that Enresa does not erroneously send radioactive material arising from the decommissioning of nuclear power plants to any smelting facility.
Policy and Law Relating to Radioactive Waste: International Direction and Human Rights
Authors: Riley P.
Published: March 2009

The anticipated doubling of world demand for electricity over the next fifty years requires that the gift of nuclear energy that has served developed nations over the past half century must not be abandoned. However, the absence of a clear and unequivocal policy regarding the storage and disposal of radioactive waste is seen by a significant section of the public as a threat to their rights and the non-existence of dedicated regulation of radioactive waste based on law has become an obstacle to the development of nuclear energy in Europe and the USA. A European survey of public opinion carried out at the request of the European Commission revealed that three-quarters of the respondents to sixteen thousand interviews believed that ‘all radioactive waste is very dangerous’. The public perception of threat has been fostered by the general lack of appreciation of the cautious system of radiation protection that has evolved from scientific observation and prediction of the risk of cancer from exposure to low level radiation. The concept of collective dose based on the system of radiation protection and applied to accident scenarios with remote possibilities, but in the absence of scientific assessment of the balance afforded by the pragmatism that man applies to everyday risks including the risk of cancer from the ever-present background of natural radiation, has added a measure of dread to the public sense of threat. That dread has been exacerbated by the emergence since September 2001 of the possibility of the use of radioactive waste as a terrorist weapon and for radioactive waste storage facilities to be seen as terrorist targets. International policy has moved from the comprehensive coverage of nuclear regulation with radioactive waste as an integral, but minor player, in the nuclear energy process to particular consideration with radioactive waste requiring specific regulation. This paper identifies the vectors that determine the direction of the policy governing radioactive waste, the moves toward consolidation of international policy separate from the body of existing nuclear law and future direction that will clear the way for a sustained, appropriate use of nuclear energy.
Electron-Sputtering-Induced Spontaneous Dust Productivity and Radiation Steadiness of Silicate Compositions Containing the Irradiated Nuclear Fuel
Authors: Zhydkov O. , Zhydkov V.
Published: March 2009

Behaviour of silicate compositions containing irradiated nuclear fuel, so-called lava-like fuel-containing materials (LFCM), which had been formed as a product of heavy nuclear accident on Chernobyl NPP 4-th Unit in 1986, have been under both the theoretical and workbench investigation. Recent experimental studies indicate, that LFCM and irradiated fuel surface does produce a submicronic radioactive dust spontaneously, i.e. without any external action. The non-contradicting quantitative explanation of observed phenomenon (giant sputtering yield) can be provided when taking into account an electron sputtering mechanism associated with Coulomb explosions, which occur intensively both just beneath a surface of materials under study and inside its volume as well. The last circumstance leads to necessity to reexamine the level of radiation damages in solids containing a large volume concentration of alpha- and beta-emitters in both. In principle, the observed phenomena must be of universal character for all high-radioactive dielectrics, but quantitative characteristics prognosis of its steadiness does depend on initial structure and properties of material. As for LFCM, it has been estimated by computer modeling based on a method of molecular dynamics (MD). The main outcome is the glass matrix cannot serve as a reliable material appointed for alpha radwaste immobilization. A submicronic radioactive dust have been already identified in the destroyed 4-th Unit premises in a large quantities; its regular pollutions in environment represents not a local, but the global problem due to a very special features concerning submicronic dust dissemination in environment.
Integrating Technical and Non-Technical Factors in Environmental Remediation Conclusions and Recommendations of the UMREG ’02 Meeting
Authors: Hagen M. , Jakubick A. T. , Lush D. , Metzler D.
Published: March 2009

The Uranium Mine Remediation Exchange Group meetings of representatives from US, Canada, Australia and Germany have been going on since 1993. The novelty of UMREG 2002 was that the traditional group from was extended to representatives from CEEC, which have a history of uranium mining and milling and are presently involved or interested in environmental remediation (ER) of the legacy. The meeting was attended and/or presentations given by representatives from Czech Republic, Estonia, Hungary, Poland, Rumania, Russian Fed. and Slovenia. Furthermore, representatives from overseas countries, Brazil, Japan and Namibia having a present or historical uranium mining and the intent to remediate the consequences of the mining provided a contribution. The extended UMREG membership confirms the increasing interest in ER remediation and in following the “Good Environmental Remediation Practice” guidelines and provides a broader idea pool for the future UMREG meetings.
Design and Siting for Large Diameter Well Type Repositories
Authors: Dmitriev Sergey , Prozorov Lev , Tkachenko Aleksey , Guskov Andrey , Korneva Svetlana
Published: March 2009

RADON enterprises are historically responsible in Russia for institutional waste of low and intermediate activity level. MosNPO RADON is a leading organization for 16 enterprises of RADON system, established in the early 60-s, only 14 from which are now in operation and have about 10% of their repositories available for upcoming waste. Construction of new repositories and selection of new perspective sites is very actual problem for RAW management in Russia now. Traditionally near surface repositories are considered to be acceptable for storage or even disposal of low and intermediate level waste (LILW), which decay to safe level in some hundreds of years. Forty years experience in LILW isolation using near surface repositories at Russian RADON facilities has shown that a lot of operational and natural factors impact on the engineered barriers and may cause failure of the isolation (freezing-thawing cycles, construction works). In addition construction of new old-type repositories requires more area. Since 1997 development and testing of Large Diameter Wells (LDW) as a new type of repositories for low and intermediate level waste is carried out at Zagorsk site. MosNPO RADON specialists developed the LDW construction technology with the aim to use such wells for LILW isolation in moraine clays. The diameter of LDW-type repository may range from 1 to 5 m depending on drilling rig capabilities and performance parameters of host rock. The depth of well (repository) depends on geological parameters and hydro-geological conditions at the site. These features affect on the siting process by additional geological and hydro-geological requirements. In result of preliminary studying of Central Russia two regions were found to be perspective for construction of LDW-type repositories.
Dry Storage of the BR3 Spent Fuel in the CASTOR® BR3 Cask
Authors: Ooms Luc , Massaut Vincent , Noynaert L. , Braeckeveldt M. , Geenen G.
Published: March 2009

The BR3 reactor was the first PWR plant installed in Europe. Started in 1962, BR3 was definitely shut down on June 30th, 1987. Used at the beginning of its life as a training device for commercial plant operators, it was also used during its whole life as test-reactor for new fuel types and assemblies. Most of the spent fuel was stored in the deactivation pool of the plant for more than 15 years. The reactor being now in decommissioning, it was decided to remove the spent fuel from the plant. After comparison of different solutions, the long term storage in dual purpose storage casks was selected in 1997. The selected CASTOR-BR3® cask is designed as a transport and storage cask for accommodating 30 spent fuel assemblies. As a type B(U) cask fitted with shock absorbers, it meets the transport requirements according to the IAEA guidelines and fulfils also the conditions for cask storage.
Utilization of Polystyrene for Floatation of Decommissioned Nuclear Submarines in Russia
Authors: Dyer R. S. , Barnes E. , Snipes R. L.
Published: March 2009

Over the past several years the Russian Federation (RF) has removed from service a large number of nuclear powered submarines (NPSs) from their Navy. The current RF concept of NPSs dismantlement typically involves the following steps: in-place floating storage, transporting (towing) to a dismantlement shipyard, removing the nuclear reactor fuel, and final dismantlement and disposal of the NPS. Appropriate technical systems and funding has not been allocated for their proper dismantlement. Therefore, long-term floating storage of the NPSs is required. To ensure that the NPSs remain afloat, a system has been developed for inserting polystyrene into the NPSs main ballast tanks (MBTs). The process has been successfully applied to a limited number of intact submarines. This system could also be applied to sections of decommissioned submarines, such as reactor compartments, currently floating in unstable conditions in bays in Northwest and Far East Russia.
A Study of Condensation Heat Transfer in a Single Mini-Tube and a Review of Korean Micro- and Mini-Channel Studies
Authors: Kim M. H. , Shin J. S. , Huh C. , Kim T. J. , Seo K. W.
Published: March 2009

This paper reviews recent Korean studies of flow characteristics, flow boiling, and flow condensation in micro- and mini-channels. The characteristics of local heat transfer and pressure drops were experimentally investigated using condensing R134a two-phase flow, in a single round tube, with an inner diameter of 0.691 mm. New experimental techniques were developed to measure the condensation heat transfer coefficient. Tests were performed for a mass flux of 100 to 600 kg/m2s, a heat flux of 5 to 20 kW/m2, and a saturation temperature of 40°C. The experimental local condensation heat transfer coefficients and two-phase frictional pressure gradients are shown. Comparisons of experimental data with existing models reveal that the correlations failed to predict the present data. This study contains the unique sub-millimeter-diameter, single round tube, condensation data reported in the literature.
Cell-Surface Adhesive Interactions in Microchannels and Microvessels
Authors: King Michael R.
Published: March 2009

Adhesive interactions between white blood cells and the interior surface of the blood vessels they contact is important in inflammation and in the progression of heart disease. Parallel-plate microchannels have been useful in characterizing the strength of these interactions, in conditions that are much simplified over the complex environment these cells experience in the body. Recent computational and experimental work by several laboratories have attempted to bridge this gap between behavior observed in flow chamber experiments, and cell-surface interactions observed in the microvessels of anesthetized animals.
Nanochannel Biomolecular Transport
Authors: Majumdar Arun
Published: March 2009

Intermolecular forces in liquids — van der Waals, electrostatic, steric — range over a distance of about 1–100 nm. Therefore, when liquids are confined in regions less than 100 nm, their behavior can be different and manipulated in unique ways. Such situations occur in nanoscale channels as well as in dense collection of biomolecules such as DNA and proteins, which range in size of 1–10 nm. Understanding fundamental transport properties of liquids under nanoscale confinement can have significant impact in biotechnology.
Single-Phase Heat Transfer and Fluid Flow in Micropipes
Authors: Celata Gian Piero
Published: March 2009

The objective of the present paper is to provide a general overview of the research carried out so far in single-phase heat transfer and flow in capillary (micro) pipes. Laminar flow and laminar-to-turbulent flow transition are analyzed in detail in order to clarify the discrepancies among the results obtained by different researchers. Experiments performed in the ENEA laboratory indicate that in laminar flow regime the friction factor is in good agreement with the Hagen-Poiseuille theory for Reynolds number below 600–800. For higher values of Reynolds number, experimental data depart from the Hagen-Poiseuille law to the side of higher f values. The transition from laminar-to-turbulent flow occurs for Reynolds number in the range 1800–2500. Heat transfer experiments show that heat transfer correlations in laminar and turbulent regimes, developed for conventional (macro) tubes, are not properly adequate for heat transfer rate prediction in microtubes.
Condensation Flow Mechanisms in Microchannels: Basis for Pressure Drop and Heat Transfer Models
Authors: Garimella Srinivas
Published: March 2009

This paper presents an overview of the use of flow visualization in micro- and mini-channel geometries for the development of pressure drop and heat transfer models during condensation of refrigerants. Condensation flow mechanisms for round, square and rectangular tubes with hydraulic diameters in the range 1–5 mm for 0 < x < 1 and 150 kg/m2-s and 750 kg/m2-s were recorded using unique experimental techniques that permit flow visualization during the condensation process. The effect of channel shape and miniaturization on the flow regime transitions was documented. The flow mechanisms were categorized into four different flow regimes: intermittent flow, wavy flow, annular flow, and dispersed flow. These flow regimes were further subdivided into several flow patterns within each regime. It was observed that the intermittent and annular flow regimes become larger as the tube hydraulic diameter is decreased, at the expense of the wavy flow regime. These maps and transition lines can be used to predict the flow regime or pattern that will be established for a given mass flux, quality and tube geometry. These observed flow mechanisms, together with pressure drop measurements, are being used to develop experimentally validated models for pressure drop during condensation in each of these flow regimes for a variety of circular and noncircular channels with 0.4 < Dh < 5 mm. These flow regime-based models yield substantially better pressure drop predictions than the traditionally used correlations that are primarily based on air-water flows for large diameter tubes. Condensation heat transfer coefficients were also measured using a unique thermal amplification technique that simultaneously allows for accurate measurement of the low heat transfer rates over small increments of refrigerant quality and high heat transfer coefficients characteristic of microchannels. Models for these measured heat transfer coefficients are being developed using the documented flow mechanisms and the corresponding pressure drop models as the basis.
Hydrodynamically Developing Dual-Wall-Driven Microchannel Flow
Authors: Tenny J. , Maynes D. , Webb B. W.
Published: March 2009

The developing flow field in a parallel plate microchannel, induced by wall motion, has been modeled numerically. The flow is driven in this scenario not by an applied pressure gradient, but by the movement of the walls in the axial direction at a constant speed. This type of flow simulates the physical driving mechanism that exists in electro-osmotically generated flow with large channel diameter-to-Debye length ratios. The results are general, however, for any microscale flow induced by wall motion and resulting viscous pumping. The dynamics of the developing flow field were explored for channel length-to-hydraulic diameter ratios (aspect ratio) of 5, 10, and 20 at ten Reynolds numbers, Re (based on the wall velocity), below Re < 2000. The results show that far from the inlet the maximum fluid velocity occurs at the walls, as is expected, and the minimum velocity occurs at the channel center. Near the channel inlet, however, the centerline velocity is not a minimum but reaches a local maximum due to a resulting pressure imbalance generated by the wall motion. The ratio of the centerline velocity to wall velocity depends on the axial distance from the channel inlet, the Reynolds number and the channel aspect ratio. As the aspect ratio increases, the centerline velocity tends to approach the wall velocity far downstream from the inlet. Increases in the Reynolds number have the opposite effect on the centerline velocity. The hydrodynamic developing region, defined by that section of the channel where the wall shear stress is changing, also depends on the channel aspect ratio and Re. In general it is found that the developing region is significantly shorter than for pressure-driven flow at the same Re.
An Experimentally Validated Model for Two-Phase Sudden Contraction Pressure Drop in Microchannel Tube Headers
Authors: Coleman John Wesley
Published: March 2009

This paper presents the results of an experimental investigation of two-phase pressure loss of R134a in microchannel headers using various end-cut techniques. Novel experimental techniques and test sections were developed to enable the accurate determination of the minor losses without obfuscating the problem with a lengthwise pressure gradient. This technique represents a departure from approaches used by other investigators that have extrapolated minor losses from air-water experiments and the combined effects of expansion, contraction, deceleration, and lengthwise pressure gradients. Pressure losses were recorded over the entire range of qualities from 100% vapor to 100% liquid. In addition, the tests were conducted for five different refrigerant mass fluxes between 185 kg/m2-s and 785 kg/m2-s using two differnt end-cut techniques. More than 790 data points were recorded to obtain a comprehensive understanding of the effects of mass flux and quality on minor pressure losses. High accuracy instrumentation such as coriolis mass flowmeters, RTDs, pressure transducers, and real-time data analyses were used to ensure accuracy in the results. The results show that many of the commonly used correlations for estimating two-phase pressure losses significantly underpredict the pressure losses found in compact microchannel tube headers. Furthermore, the results show that the end-cut technique can substantially affect the pressure losses in microchannel headers. A new model for estimating the pressure loss in microchannel headers is presented and a comparison of the end-cut techniques on the minor losses is reported.
Multiplicity and Stability of Forced Convective Heat Transfer in Microchannels
Authors: Wang Liqiu , Yang Tianliang
Published: March 2009

A numerical study is made on the fully-developed bifurcation structure and stability of the forced convection in a curved microchannel of square cross-section. Two symmetric and four asymmetric solution branches are found. Thus a rich solution structure is found with up to eleven solutions over certain ranges of governing parameters. This multiplicity is at least partially responsible for the large differences in the reported friction factors and heat transfer coefficients in the literature. Dynamic responses of the multiple solutions to finite random disturbances are examined by the direct transient computation. It is found that possible physically realizable fully-developed flows evolve, as the Dean number (or Reynolds number) increases, from a stable steady 2-cell state at lower Dean number to a temporal periodic oscillation state, another stable steady 2-cell state, a temporal intermittent oscillation, and a chaotic temporal oscillation.
Fluid Flow and Heat Transfer in Microchannels With Rectangular Cross Section
Authors: Jung Jung-Yeul , Kwak Ho-Young
Published: March 2009

Forced convective heat transfer coefficients and friction factor for flow of water and FC-72 in microchannels with a rectangular cross section were measured. An integrated microsystem consisting of five microchannels on one side and a localized heater and seven polysilicon temperature sensors along the selected channels on the other side was fabricated by using a double side polished silicon wafer. For the microchannels tested, the friction factor constant C = f ReDh obtained are values between 35.7 and 81.9, which are close to the theoretical value of 57.0. The measured Nusselt number in the laminar regime tested could be correlated by a correlation, Nu = A ReDh1.37 Pr1/3 where A is the value between 0.000 454 and 0.000 646.
Water Single-Phase Fluid Flow and Heat Transfer in Capillary Tubes
Authors: Bucci A. , Celata G. P. , Cumo M. , Serra E. , Zummo G.
Published: March 2009

This paper reports the results of an experimental investigation of fluid flow and single-phase heat transfer of water in stainless steel capillary tubes. Three tube diameters are tested: 172 μm, 290 μm and 520 μm, while the Reynolds number varying from 200 up to 6000. Fluid flow experimental results indicate that in laminar flow regime the friction factor is in good agreement with the Hagen-Poiseuille theory for Reynolds number below 800–1000. For higher values of Reynolds number, experimental data depart from the Hagen-Poiseuille law to the side of higher f values. The transition from laminar to turbulent regime occurs for Reynolds number in the range 1800–3000. This transition is found in good agreement with the well known flow transition for rough commercial tubes. Heat transfer experiments show that heat transfer correlations in laminar and turbulent regimes, developed for conventional size tubes, are not adequate for calculation of heat transfer coefficient in microtubes. In laminar flow the experimental values of heat transfer coefficient are generally higher than those calculated with the classical correlation, while in turbulent flow regime experimental data do not deviate significantly from classical heat transfer correlations. Deviation from classical heat transfer correlations increase as the channel diameter decrease.
Interfacial Electrokinetic Effects on Fluid Flow in Microchannel by a Generalized Lattice Boltzmann Model
Authors: Li Baoming , Chai Steven , Tian Fuzhi , Kwok Daniel Y.
Published: March 2009

A diffuse electric double layer (EDL) in microchannel flow created by the charged surface in contact with an electrolyte solution is characterized by the so-called Debye-Hu¨ckel screening length, which depends on the ionic strength of the solution. Usually, the electric double layer thickness, which is from several nanometers to a few hundreds nanometers, is small in comparison with the microchannel height of a few tens microns. Traditional computational fluid dynamics (CFD) methods for macroscopic hydrodynamic equations have difficulties in such complex fluid dynamics problems involving microscale surface interactions. In this paper, we employ a two-dimensional generalized lattice Boltzmann model in the presence of external forces on a rectangular grid with an arbitrary aspect ratio and nonuniform mesh grids. A modified Poisson-Boltzmann equation is applied to examine the adsorption of ions from solution to a charged surface and obtain the electrostatic potential and ion distribution. An example with electroviscous flow in microchannel is used to validate the prediction ability of the model proposed here. Excellent agreement with experimental results was found.
Behaviors of Micropolar Flows in a Rotating Annulus
Authors: Kim Youn J.
Published: March 2009

An analysis is presented for the problem of micropolar flows in the annulus between two steadily rotating concentric cylinders. The local effects arising from microstructure and intrinsic motion of the fluid element that will affect the flow motion are considered. Especially, the effects of non-zero values of micro-gyration vector on the wall boundary conditions are investigated, using micropolar fluid theory. Numerical results of velocity distribution of micropolar fluids are compared with the corresponding flow problems for a Newtonian fluid. Also, the results of the surface friction coefficient and the couple stress coefficient at the inner and outer surfaces are prepared with various values of fluid properties and flow conditions.