Sample records for athene reactor

  1. Ancient Astronomical Monuments of Athens (United States)

    Theodossiou, E.; Manimanis, V. N.


    In this work, four ancient monuments of astronomical significance found in Athens and still kept in the same city in good condition are presented. The first one is the conical sundial on the southern slope of the Acropolis. The second one is the Tower of the Winds and its vertical sundials in the Roman Forum of Athens, a small octagonal marble tower with sundials on all 8 of its sides, plus a water-clock inside the tower. The third monument-instrument is the ancient clepsydra of Athens, one of the findings from the Ancient Agora of Athens, a unique water-clock dated from 400 B.C. Finally, the fourth one is the carved ancient Athenian calendar over the main entrance of the small Byzantine temple of the 8th Century, St. Eleftherios, located to the south of the temple of the Annunciation of Virgin Mary, the modern Cathedral of the city of Athens.

  2. Alkmaioniderne - politik og sport i antikkens Athen

    DEFF Research Database (Denmark)

    Nielsen, Thomas Heine


    Artiklen diskuterer en enkelt elitefamilies engagement i politik og sport i det 6. og 5. århs. Athen......Artiklen diskuterer en enkelt elitefamilies engagement i politik og sport i det 6. og 5. århs. Athen...

  3. 2013 Athens-Clarke County, Georgia Imagery (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set consists of 0.5 foot pixel resolution, four band (RGB, Near IR) orthoimages covering Athens-Clarke Georgia. An orthoimage is remotely sensed image data...

  4. Micromeria acropolitana (Lamiaceae) rediscovered in Athens (Greece)

    DEFF Research Database (Denmark)

    Tan, Kit; Tsounis, Gregory; Tsounis, Lambros


    Micromeria acropolitana (Lamiaceae) was first collected in 1906 from the Acropolis, Athens and considered extinct until its rediscovery in 2006, a hundred years later. Its greatest threat within the archaeological site is human disturbance. It has survived in its original habitat, the natural rock...

  5. Virtual Visit to the ATLAS Control Room by Athens College

    CERN Multimedia

    ATLAS Experiment


    Athens College, is part of HAEF (Hellenic American Educational Foundation). It is an Athens high-school with great a tradition and an important contribution to the scientific world of Greece and society. Its graduates are distinguished personalities of the scientific, artistic, economic and political life, both in Greece and internationally.

  6. Simulation of the convective mixed layer in Athens

    Energy Technology Data Exchange (ETDEWEB)

    Frank, H.P. [Risoe National Lab., Roskilde (Denmark)


    The region of Athens, Greece, has a highly complicated terrain with irregular coastline and mountains next to the sea. This results in complex flow fields. A case study of a simulation of a sea breeze with the Karlsruhe Atmospheric Mesoscale model KAMM is presented together with remarks on the advection of mixed layer air. The valley of Athens is open to the sea towards the south-west and surrounded by mountains on the other sides. Gaps between the mountains channel the flow into the valley. Simulations were done for 14 September 1994 to compare them with measurements at 6 masts by Risoe during the MEDCAPHOT-TRACE experiment. (au)

  7. Variation in working effort in Danish Little Owls Athene noctua

    DEFF Research Database (Denmark)

    Holsegård-Rasmussen, Miriam H.; Sunde, Peter; Thorup, K.


    Locomotion is costly and should therefore serve a purpose according to the principle of optimal behaviour. In this light, we studied variation in nocturnal activity of radio-tagged Little Owls Athene noctua in Denmark where, after a decline of at least 30 years, the species is threatened with ext...

  8. Reproductive working effort in Danish little owl (Athene noctua)

    DEFF Research Database (Denmark)

    Holsegård-Rasmussen, M.; Sunde, P.; Thorup, K.

    Reduced reproductive success, caused by energy constraints during breeding, is suspected to be one of the reasons for an ongoing decline in the Danish population of little owls (Athene noctua). To measure any food stress during the breeding period, working effort was defined as the minimum flight...

  9. art@CMS at 2016 Athens Science Festival

    CERN Multimedia

    Athens, Greece


    This video documents the art@CMS activities during the 2016 Athens Science Festival including an interactive multimedia installation, panel discussion, teachers' workshop and a closing keynote by Prof. John Ellis. The video has been supported by CREATIONS Horizon 2020 EU project.

  10. Protozoal hepatitis in a western burrowing owl (Athene cunicularia hypugaea) (United States)

    Franson, J. Christian


    A western burrowing owl (Athene cunicularia hypugaea) found dead in southern California had many light-colored lesions visible grossly on its liver, and histopathology revealed extensive necrosis throughout the hepatic parenchyma. Single-celled organisms were seen in clear spaces within the areas of necrosis. The owl was diagnosed with protozoal hepatitis.

  11. Paleoclimatic change, disaster history and the urbanscape transitions in Athens (United States)

    Yang, Liang


    Past abrupt climate changes on millennium time scales have received wide attention among natural and social scientists, also because of today's rapid climate changes and their extensive impacts on our society. In the eastern Mediterranean area, coherent patterns and synchronous events in history suggest obvious links between urban development and climate forcing. The city of Athens as the origin of ancient Greek civilization experienced many periods of prosperity and decay. Though the transitions were mostly dominated by wars and power changes between empires, severe climate events and natural disasters may also considerably have shaped the process of Athens' development. Among natural disasters, earthquake, tsunami, flood and wildfire were the main forces that stressed the development of Athens. To recover from and respond to these disaster impacts, the city was thereafter developed in ways that either changed the ever existed city patterns or guided sensitive areas to specific directions, which could have transformed the urbanscape gradually. However, the possibility that these transitions may have been responses/resilience strategies triggered by abrupt climate events has so far hardly been explored. With extensive literature review, existing archaeological records and paleoclimate reconstruction modelling results, this study analyzes the large scale climate variations, related environment changes in mesoscale, aiming at setting into context the local natural disasters in Athens and its surrounding areas during the Holocene period. The study treats a number of important climate events in the area and urban transitions of the city, of which the integration of all these elements and insights from recent analysis throw some new light on understanding the forcing-transition process. Preliminary results indicate unclear link of climate forcing and urban transition over the whole city, but a few signs of possible linkages were recognized at specific blocks of Athens

  12. Foot and ankle injuries during the Athens 2004 Olympic Games

    Directory of Open Access Journals (Sweden)

    Mirones Steven


    Full Text Available Abstract Background Major, rare and complex incidents can occur at any mass-gathering sporting event and team medical staff should be appropriately prepared for these. One such event, the Athens Olympic Games in 2004, presented a significant sporting and medical challenge. This study concerns an epidemiological analysis of foot and ankle injuries during the Games. Methods An observational, epidemiological survey was used to analyse injuries in all sport tournaments (men's and women's over the period of the Games. Results A total of 624 injuries (525 soft tissue injuries and 99 bony injuries were reported. The most frequent diagnoses were contusions, sprains, fractures, dislocations and lacerations. Significantly more injuries in male (58% versus female athletes (42% were recorded. The incidence, diagnosis and cause of injuries differed substantially between the team sports. Conclusion Our experience from the Athens Olympic Games will inform the development of public health surveillance systems for future Olympic Games, as well as other similar mass events.

  13. Dental data of the Athens 2004 Olympic and Paralympic Games. (United States)

    Vougiouklakis, G; Tzoutzas, J; Farmakis, E-T; Farmakis, E-E; Antoniadou, M; Mitsea, A


    The Athens University, School of Dentistry, accepted the challenge to organize the Dental Health Services in the Athens 2004 Olympic and Paralympic Games in order to provide the best quality of oral health services to the athletes, coaches, escort members and Olympic Village personnel. Data from the whole activity protocol of the Athens 2004 Games Dental Health Services - the reception, admission and treatment protocols, the facilities and the infrastructure, the number of cases treated per specialty and the experience gained - were recorded. During the Olympic Games, there were more than 1400 dental cases in more than 650 patients, elite athletes, escort members, coaches and staff of the Olympic Village. Among them 313 fillings, 100 root canal therapies, 57 mouthguards and 9 dental trauma cases were treated. During the Paralympic Games, there were more than 240 dental cases in more than 220 patients. Among them 73 fillings, 12 root canal therapies, 21 extractions and 3 dental trauma cases were treated. In such events, highly trained dentists are needed and if possible, specialized in operative dentistry or endodontics. The role of team dentist seems to be of great importance.

  14. Medication use by athletes during the Athens 2004 Paralympic Games. (United States)

    Tsitsimpikou, C; Jamurtas, A; Fitch, K; Papalexis, P; Tsarouhas, K


    To examine the use of food supplements and pharmaceutical preparations by elite Paralympic athletes. Survey study. Athens 2004 Paralympic Games. Data obtained from two sources: (i) athletes' declaration of intake of drugs/supplements recorded on the Doping Control Official Record during sample collection for doping control; (ii) athletes' application forms for granting of a therapeutic use exemption. Classification of declared food supplements according to the active ingredient and medications according to therapeutic actions and active compounds. 64.2% of the athletes tested for doping control declared use of medications or food supplements, and 81.3% of these athletes declared intake of fewer than four preparations. Non-invasive routes of administration dominated. Food supplements (42.1%) were popular, and drugs used to treat several pathological conditions noted. Non-steroidal anti-inflammatory agents and analgesics were commonly used (9.8% and 5.6%, respectively). The prevalence of inhaled beta2-agonist use (4.8%) was higher than expected and exceeded that at the Athens Olympic Games. This review, the first to examine elite Paralympic athletes, shows a more rational approach to the use of medication and food supplements, but a similar consumption pattern to that of athletes at the Athens Olympic Games. Because of the dearth of such studies, consumption trends among Paralympic athletes remain unclear. The need to counsel athletes with disabilities on their nutritional needs is confirmed, and close monitoring by healthcare professionals is recommended.

  15. On Three Locations Connected with Aristotle: Ancient Stagira - Mieza - Athens

    Directory of Open Access Journals (Sweden)

    Valentin Kalan


    Full Text Available The last decade has witnessed well-nigh simultaneous discoveries on three archaeological sites connected with Aristotle, which have eliminated many cliches and mistaken assumptions about the philosopher's life and work. These are: (1 his native town of Stagira, or Stagirus; (2 his school in the Macedonian town of Mieza; and (3 the location of the Peripatetic school, the Lyceum, at Athens. The first part of the article thus briefly surveys the most important discoveries about the layout of ancient Stagira, as described in the monograph by Konstantinos Sismanidis. The  main  archaeological finds include an early classical town-wall (an admirable example of military architecture, the  stoa,  an  aqueduct, the  foundations of three  temples, silver coins with the type of a wild boar, etc.-The second part moves from a preliminary description of Mieza to an  attempt at  reconstructing the philosophical ideas transmitted by Aristotle to Alexander and  his peers at Mieza- not  Pella-, using  Plutarch's Life of Alexander as a starting-point. Such education would have been  impossible if the Macedonians had not been  Greeks  and  their  language a Greek  dialect, and  it is the failure to realize this fact that has long impeded- and  still does- our understanding of Aristotle's attitude to Philip and  Alexander. The article touches on  the potential relevance of Alexander's politics for  the  present, which  may be sought in  its interplay of  two processes: the  spreading of Greek culture abroad on  the  one hand, and, on  the  other, the  preservation of  other cultures with which  the Greeks came into contact. The third part, drawing on  Rupp's book Peripatoi, presents the  latest archaeological discoveries relating to the exact location of Aristotle's Peripatos in Athens. In 323 BC -immediately after Alexander's death- Aristotle retired from Athens for the  second time, his life endangered by the  prevailing anti

  16. "Stay in Synch!": Performing Cosmopolitanism in an Athens Festival

    Directory of Open Access Journals (Sweden)

    Vassiliki Lalioti


    Full Text Available Synch is an electronic music festival that takes place in Athens every summer and brings together people of various cultural origins and musical and aesthetic interests. As a total performance event, Synch becomes a site of complexity, polyvocality and hybridity; a site which allows participants to create and express cosmopolitan attitudes of openness for others, people, ideas and experiences. Adopting an anthropological/ethnographic perspective, this paper moves beyond distinctions between elite vs. ordinary and consumer vs. ethical cosmopolitanism, and investigates Synch as a site where local and trans-local aspects of life and a set of socio-cultural meanings in Greece today are being negotiated.

  17. The urban roots of anti-neoliberal social movements: the case of Athens, Greece

    NARCIS (Netherlands)

    Arampatzi, A.; Nicholls, W.J.


    The recent rounds of anti-neoliberal mobilizations in Europe have shown to be rooted in cities. Whereas Madrid has become a central hub in Spain’s social movement, Athens has assumed a central and centralizing role in Greece. Through a case study on Athens, Greece, this paper aims to show how cities

  18. ‘One step beyond’ – Re-Think Athens, towards a new city centre

    NARCIS (Netherlands)

    Klemm, W.


    On the 27 February it is announced at the Onassis Cultural Centre in Athens (=opdrachtgever) that the OKRA team of OKRA in collaboration with Mixst urbanism and Wageningen University, has won the prestigious international architectural competition ReThink Athens, towards a new city centre. The team

  19. Mercury in the Urban Topsoil of Athens, Greece

    Directory of Open Access Journals (Sweden)

    Efstratios Kelepertzis


    Full Text Available The present study documents the Hg content in 45 urban topsoil samples from the highly urbanized city of Athens, Greece. The Hg concentrations were quantified by applying aqua regia digestion on the <100 μm soil fraction followed by inductively coupled plasma-mass spectrometry (ICP-MS with a detection limit of 5 μg·kg−1. The median concentration of Hg in Athens soil is 96 μg·kg−1; ten out of 45 soil samples were found to contain Hg concentrations higher than 200 μg·kg−1, which is the maximum concentration value expected to be present in normal uncontaminated soils. Results obtained by multivariate principal component and hierarchical cluster analysis incorporating a large suite of chemical elements were notably effective for elucidating the anthropogenic origin of Hg in the studied soil. The elevated concentrations are most likely related to site-specific point source contamination rather than to the widely documented influences from the vehicular traffic emissions in urban settings. Given the proximity of urban population to the contaminated urban soils, we suggest the implementation of different soil extraction tests with the aim to evaluate the fraction of soil Hg available for absorption by the human body.

  20. Special sessions of the Athens Physics Workshop: Commissioning, etc...

    CERN Multimedia

    Krasny, W

    The first week of LHC proton-proton collisions will undoubtedly be both busy and exciting. Several breath-taking discovery scenarios have been presented during this Athens Physics workshop. Within the first week of beam-beam collisions we may already learn of how many extra dimensions we are condemned to live and how dull the matter of which we are made is (cf. for many of us - more fascinating super-symmetric form). By the eve of the Seventh day several black holes may have already been created. It may take more time to produce the first ("Big") Higgs and Ian Hinchliffe's and J.E. Garcia's favorite Little Higgs particles. Whilst waiting for them we may already acquire a sufficient training in very fashionable alchemist skills of quantum loop cancellations to forecast what awaits us in the second and in the subsequent weeks of data taking. Two (complementary?) ways to get ready for the first collisions have been proposed in Athens. The first one, by the local workshop organizers, taking care of all aspects o...

  1. Human-biometeorological assessment of heat waves in Athens (United States)

    Matzarakis, Andreas; Nastos, Panagiotis T.


    The goal of this study is the analysis of heat waves and their impact on humans, using human biometeorological indices, which are based on the energy balance of the human body. The implications for humans are not only described through the intensity of the heat waves, but also through their duration over consecutive days. Both intensity and duration were analyzed for the Greater Athens Area during the period 1955 to 2001. The analysis was carried out using the daily physiologically equivalent temperature and the daily minimum air temperature. Based on these two parameters, the results showed an increase in the average duration of heat waves. Furthermore, the use of the Gaussian filter revealed the intra-annual variation of heat stress conditions and their relevance to humans. The results could be used for the management of the negative consequences of heat waves in cities suffering from environmental pollution and also for climate impact studies.

  2. H Reactor (United States)

    Federal Laboratory Consortium — The H Reactor was the first reactor to be built at Hanford after World War II.It became operational in October of 1949, and represented the fourth nuclear reactor on...

  3. 5. Looking at the Acropolis of Athens from Modern Times to Antiquity


    St Clair, William


    The Acropolis of Athens is one of the most famous places on earth, visited by over a million people every year, and instantly recognisable by millions more who know it only from pictures. With posters and postcards displayed in every street kiosk and hotel lobby in Athens, and countless images encountered in books, films, television, brochures, advertising, and social media in countries round the world, it must now be impossible for any visitor, whether a Greek child on a first educational vi...

  4. Oxidative Potential of ambient particulate matter in Athens, Greece. (United States)

    Paraskevopoulou, Despina; Bougiatioti, Aikaterini; Fang, Ting; Liakakou, Eleni; Weber, Rodney; Nenes, Athanasios; Mihalopoulos, Nikolaos


    Exposure of populations to airborne particulate matter (PM) is a leading cause of premature death worldwide. Oxidative stress resulting from exposure of chemical species present in PM is a mechanism thought to cause adverse health effects. Apart from radicals present in aerosol, species that can catalytically deplete the antioxidant buffering capacity of cells, called Oxidative Potential (OP), are thought to be particularly toxic. The variability of OP over location, particle age, source and environmental conditions is virtually unknown for most populated regions of the world. Motivated by this, we have built and deployed one of the first operational measurements of OP in Europe at the National Observatory of Athens site in downtown Athens, Greece. OP for fine and coarse mode is measured using a semi-automated dithiothreitol (DTT) assay developed at the Georgia Institute of Technology; the assay measures the oxidation rate of DTT by water-soluble aerosol constituents, and simulates the rate at which the same compounds would deplete antioxidants in-vivo. The DTT oxidation rate per unit volume of air (water-soluble "DTT activity") and aerosol size class (fine, coarse) are used as a measure of aerosol toxicity. We present continuous (24hr average) OP measurements in downtown Athens from July 2016 to January 2017, conducted through quartz fiber filter analysis. The dataset covers a broad range of aerosol sources (pollution from Europe, regional and local biomass burning, dust, marine aerosol, biogenic aerosol) and meteorological conditions. The daily water-soluble DTT activity ranges between 0.02-0.81 nmolmin-1 m-3 (averaging at 0.24 nmolmin-1 m-3) for fine aerosol and between 0.01-0.52 nmolmin-1 m-3 (averaging at 0.08 nmolmin-1 m-3) for coarse particulate matter, indicating that water-soluble fine mode aerosol components possess a significant fraction of the OP. The seasonal variability demonstrates a higher DTT activity during the coldest period of the year for both

  5. [Attempted suicide during the financial crisis in Athens]. (United States)

    Stavrianakos, K; Kontaxakis, V; Moussas, G; Paplos, K; Papaslanis, T; Havaki-Kontaxaki, B; Papadimitriou, Gn


    Suicidal behavior is considered as the result of complex cognitive and emotional processes and it is a timeless, global and multifactorial phenomenon. Periods of financial crises in the past, such as the Great Depression in the USA in 1929 and the economic crises of Asia, Russia and Argentina in the late 1990s, have been associated with impairment of mental health of the economically affected. Unemployment, job insecurity, debts, poverty and social exclusion seems to lead to higher incidence of anxiety and depressive symptoms and increased suicidality. Alcohol and substance use and the reduction of the state budget for health services reinforce the negative effects of the economic recession on mental health. The financial crisis which currently affects many European countries began in 2008 and its impact on the mental health of European citizens is in progress. Greece is probably the most affected country by the European financial crisis. The aim of this study is to investigate the potential impact of the crisis' consequences on the attempted suicide rates in the Athens population and the differentiation of suicide attempters on social, demographic and clinical-psychopathological parameters during the crisis. A retrospective study was conducted. The semi-structured records of 165 attempters who were hospitalized in the Internal Medicine Clinics of the "Sotiria" General Hospital in Athens, after attempted suicide in the years 2007 and 2011, before and during the financial crisis respectively, were studied. Among suicide attempters 95(57.6%) were suffering from mental disorders. Most often diagnoses were these of mood disorders (n=60, 63.2%). Demographic data, current psychiatric disorder, previous suicide attempt and severity of psychopathology at the time of suicide attempt were recorded for each patient. Furthermore, the severity of each suicide attempt was estimated. Suicide attempts were 70 in 2007, before the financial crisis (mean age 36.9 years, 71% women

  6. Desert dust outbreaks and respiratory morbidity in Athens, Greece. (United States)

    Trianti, Stavroula-Myrto; Samoli, Evangelia; Rodopoulou, Sophia; Katsouyanni, Klea; Papiris, Spyros A; Karakatsani, Anna


    Ambient particulate matter (PM) has an adverse effect on respiratory morbidity. Desert dust outbreaks contribute to increased PM levels but the toxicity of desert dust mixed with anthropogenic pollutants needs clarification. We identified 132 days with desert dust episodes and 177 matched days by day of the week, season, temperature and humidity between 2001 and 2006 in Athens, Greece. We collected data on regulated pollutants and daily emergency outpatient visits and admissions for respiratory causes. We applied Poisson regression models adjusting for confounding effects of seasonality, meteorology, holidays and influenza epidemics. We evaluated the sensitivity of our results to co-pollutant exposures and effect modification by age and sex. A 10 μg/m3 increase in PM10 concentration was associated with 1.95% (95% confidence interval (CI): 0.02%, 3.91%) increase in respiratory emergency room visits. No significant interaction with desert dust episodes was observed. Compared with non-dust days, there was a 47% (95% CI: 29%, 68%) increase in visits in dust days not adjusting for PM10. Desert dust days were associated with higher numbers of emergency room visits for asthma, chronic obstructive pulmonary disease and respiratory infections with increases of 38%, 57% and 60%, respectively (p desert dust days and were further confounded by co-pollutants. Desert dust episode days are associated with higher respiratory emergency room visits and hospital admissions. This effect is insufficiently explained by increased PM10 levels.

  7. Reports from the combined performance sessions in Athens Physics Workshops

    CERN Multimedia

    Alexa, C

    laurent & calin 2003 Athens: the Titan ATLAS, after weighing the Earth many years ago, continues its search on the mass problem and on the Higgs in particular … and gives results on the beam tests and simulations. Inner detector layout and flavor tagging Much effort has been dedicated to improve b-tagging efficiency, developing new sophisticated methods and more precise tuning of the good old and simple algorythms. But, we have to wait for eight months of datataking to reach an efficient b-tagging. The loss of performance, mainly produced by the increase of the b-layer radius and material changes, was compensated by the software improvements and verified on DC1 data.  Undoubtedly, the confirmation that the required performance can be achieved is coming from the test beams studies. The detector alignment has well advanced software and the tools are waiting to be used efficiently. Even if there are many things to be understood in lead-lead central collisions, encouraging b-tagging resul...

  8. Reactor Physics

    Energy Technology Data Exchange (ETDEWEB)

    Ait Abderrahim, A


    The Reactor Physics and MYRRHA Department of SCK-CEN offers expertise in various areas of reactor physics, in particular in neutronics calculations, reactor dosimetry, reactor operation, reactor safety and control and non-destructive analysis of reactor fuel. This expertise is applied in the Department's own research projects in the VENUS critical facility, in the BR1 reactor and in the MYRRHA project (this project aims at designing a prototype Accelerator Driven System). Available expertise is also used in programmes external to the Department such as the reactor pressure steel vessel programme, the BR2 reactor dosimetry, and the preparation and interpretation of irradiation experiments by means of neutron and gamma calculations. The activities of the Fuzzy Logic and Intelligent Technologies in Nuclear Science programme cover several domains outside the department. Progress and achievements in these topical areas in 2000 are summarised.

  9. Reactor safeguards

    CERN Document Server

    Russell, Charles R


    Reactor Safeguards provides information for all who are interested in the subject of reactor safeguards. Much of the material is descriptive although some sections are written for the engineer or physicist directly concerned with hazards analysis or site selection problems. The book opens with an introductory chapter on radiation hazards, the construction of nuclear reactors, safety issues, and the operation of nuclear reactors. This is followed by separate chapters that discuss radioactive materials, reactor kinetics, control and safety systems, containment, safety features for water reactor

  10. Reactor operation

    CERN Document Server

    Shaw, J


    Reactor Operation covers the theoretical aspects and design information of nuclear reactors. This book is composed of nine chapters that also consider their control, calibration, and experimentation.The opening chapters present the general problems of reactor operation and the principles of reactor control and operation. The succeeding chapters deal with the instrumentation, start-up, pre-commissioning, and physical experiments of nuclear reactors. The remaining chapters are devoted to the control rod calibrations and temperature coefficient measurements in the reactor. These chapters also exp

  11. Avaliação da onda b do eletrorretinograma na Athene cunicularia Evaluation of the b-wave electroretinogram in Athene cunicularia

    Directory of Open Access Journals (Sweden)

    Márcio Penha Morterá Rodrigues


    Full Text Available OBJETIVO: Avaliar a onda b do eletrorretinograma da coruja buraqueira (Athene cunicularia, diferenciando a resposta elétrica retiniana em ambiente fotópico e escotópico. MÉTODOS: Foi realizado estudo observacional transversal, com o registro do eletrorretinograma full field de quatorze olhos, sendo sete estimulados em ambiente fotópico e sete em ambiente escotópico sob estímulo com luz branca seguindo protocolo da ISCEV. RESULTADOS: As respostas elétricas da retina da espécie estudada para o espectro de luz aplicado mostraram-se presentes em ambos ambientes, não havendo diferença estatisticamente significativa da resposta elétrica da retina da Athene cunicularia quando estimulada com luz branca, tanto em ambiente escotópico quanto fotópico. CONCLUSÃO: Os dados nos permitem, portanto, inferir que a percepção pela Athene cunicularia da cor branca é a mesma, no claro e no escuro, o que pode ser responsável pela capacidade adaptativa da espécie no seu habitat natural.PURPOSE: To evaluate b-wave of the electroretinogram of the burrowing owl (Athene cunicularia, differentiating the retinal electric reply in photopic and scotopic environment. METHODS: Transversal observational study was carried through, with the register of the full field electroretinogram of fourteen eyes; seven were stimulated in photopic environment and seven in scotopic environment using with white light according to the ISCEV protocol. RESULTS: The electrical responses of the retina of the species studied showed no statistically significant difference for the applied spectrum of white light in both scotopic photopic environments. CONCLUSION: The data allow us, therefore, to infer that the perception of the Athene cunicularia of the white color is the same one, in clear and dark environments, what it can be responsible for the adaptive capacity of the species in their natural habitat.

  12. Research Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Martens, Frederick H. [Argonne National Laboratory; Jacobson, Norman H.


    This booklet discusses research reactors - reactors designed to provide a source of neutrons and/or gamma radiation for research, or to aid in the investigation of the effects of radiation on any type of material.

  13. Reproductive consequences of farmland heterogeneity in little owls (Athene noctua). (United States)

    Michel, Vanja T; Naef-Daenzer, Beat; Keil, Herbert; Grüebler, Martin U


    The amount of high-quality habitat patches, their distribution, and the resource accessibility therein play a key role in regulating habitat effects on reproductive success. Heterogeneous habitats offer non-substitutable resources (e.g. nest sites and food) and substitutable resources (e.g. different types of food) in close proximity, thereby facilitating landscape complementation and supplementation. However, it remains poorly understood how spatial resource separation in homogeneous agricultural landscapes affects reproductive success. To fill this gap, we investigated the relationships between farmland heterogeneity and little owl (Athene noctua) reproductive success, including potential indirect effects of the heterogeneity-dependent home-range size on reproduction. Little owl home-ranges were related to field heterogeneity in summer and to structural heterogeneity in winter. Clutch size was correlated with the amount of food-rich habitat close to the nest irrespective of female home-range size, suggesting importance of landscape complementation. Nestling survival was positively correlated with male home-range size, suggesting importance of landscape supplementation. At the same time, fledgling condition was negatively correlated with male home-range size. We conclude that decreasing farmland heterogeneity constrains population productivity by two processes: increasing separation of food resources from nest or roost sites results in low landscape complementation, and reduction of alternative food resources limits landscape supplementation. Our results suggest that structural heterogeneity affects landscape complementation, whereas the heterogeneity and management of farmland fields affect landscape supplementation. Thus, to what extent a reduction of the heterogeneity within agricultural landscapes results in species-specific habitat degradation depends on the ecological processes (i.e. landscape complementation or supplementation) which are affected.

  14. CONVECTION REACTOR (United States)

    Hammond, R.P.; King, L.D.P.


    An homogeneous nuclear power reactor utilizing convection circulation of the liquid fuel is proposed. The reactor has an internal heat exchanger looated in the same pressure vessel as the critical assembly, thereby eliminating necessity for handling the hot liquid fuel outside the reactor pressure vessel during normal operation. The liquid fuel used in this reactor eliminates the necessity for extensive radiolytic gas rocombination apparatus, and the reactor is resiliently pressurized and, without any movable mechanical apparatus, automatically regulates itself to the condition of criticality during moderate variations in temperature snd pressure and shuts itself down as the pressure exceeds a predetermined safe operating value.

  15. Virtual Visit to the ATLAS Control Room by three High Schools in Athens

    CERN Multimedia


    Forty-eight students/members of physics groups from three high schools in Athens (Doukas Lyceum, Gennadios Experimental Lyceum of Athens, Lyceum of Kaisariani) have recently joined forces in a series of collaborative educational activities on particle physics, initiated by teachers participating in last year`s Greek Teachers Programme at CERN, and supported by the LHC-ATLAS Group of the University of Athens and CERN Education Group in the framework of the Discover the COSMOS project. Hosted in the premises of Doukas Lyceum, this virtual visit will be combined with a dedicated Masterclass during which students will learn how to analyse collision events from the ATLAS experiment with the use of the HYPATIA online applet.

  16. Post-fledging behaviour of juveniles in the little owl (Athene noctua)

    DEFF Research Database (Denmark)

    Pedersen, Dorthe; Thorup, Kasper; Sunde, Peter


    Before dispersal, social and spatial behaviour in owls has only been briefly studied. We used radio tracking to monitor age-influenced social and spatial behaviour in 10 juvenile Little Owls (Athene noctua) from nests in Northern Jutland, Denmark. On average, the post-fledging dependency period l...... consistent with the notion that food provided by the parents decreased as juvenile foraging skills increased.......Before dispersal, social and spatial behaviour in owls has only been briefly studied. We used radio tracking to monitor age-influenced social and spatial behaviour in 10 juvenile Little Owls (Athene noctua) from nests in Northern Jutland, Denmark. On average, the post-fledging dependency period...

  17. Aerosol Monitoring over Athens Using Satellite and Ground-Based Measurements


    Kaskaoutis, D. G.; Sifakis, N.; Retalis, A.; Kambezidis, H. D.


    Satellite data of moderate spatial resolution (MODIS and MERIS) were used to retrieve the aerosol optical depth (AOD) over the urban area of Athens. MODIS products were obtained at a horizontal resolution of 10 by 10 km2 centered over Athens, while the differential textural analysis (DTA) code was applied to MERIS images to retrieve relative-to-reference AOD with a resolution of 260 m by 290 m. The possibility of exploiting the full resolution of MERIS data in retrieving AOD over a grid of a ...

  18. REACTOR COOLING (United States)

    Quackenbush, C.F.


    A nuclear reactor with provisions for selectively cooling the fuel elements is described. The reactor has a plurality of tubes extending throughout. Cylindrical fuel elements are disposed within the tubes and the coolant flows through the tubes and around the fuel elements. The fuel elements within the central portion of the reactor are provided with roughened surfaces of material. The fuel elements in the end portions of the tubes within the reactor are provlded with low conduction jackets and the fuel elements in the region between the central portion and the end portions are provided with smooth surfaces of high heat conduction material.

  19. The 4th ATLAS Physics Workshop in Athens: The discussions, social events, environment, atmosphere, etc.

    CERN Multimedia

    Kawagoe, K

    Over 220 people attended the 4th Atlas Software Workshop in Athens, Greece, a place with a history of thousands of years of scientific achievement. The workshop was hosted by the University of Athens, the National Technical University of Athens, and the Aristotle University of Thessalonki. The venue for the meeting was the newly opened Conference Center of the Physics Department of the University of Athens which featured very comfortable plush red chairs (too comfortable for some of the more jet-lagged workshop participants!). Fig.1. Participants gathering in front of the Conference Center. The workshop schedule was structured to allow plenty of time during breaks for the many lively discussions that developed from the presentations. Ample supplies of coffee, juice, and cookies fueled the discussions. Discussions continued over lunches featuring Greek Salads and other tasty fare. The food was so good that one speaker offered the meal tickets as prize for answering a quiz at the end of her talk! The w...

  20. Rain intensity over specific rain thresholds in Athens and Thessaloniki, Greece (United States)

    Philandras, C. M.; Nastos, P. T.; Kapsomenakis, J.; Repapis, C. C.


    It is well documented that climatic change has caused significant impacts in the water cycle and great spatial and temporal variability of the rain events. The rain scarcity in many cases is associated with extreme convective weather resulted in flash floods, which threatens the human life and the existed infrastructure. In this study, the annual mean rain intensity (mm/h) along with the annual number of rain days for rain events over specific rain thresholds, such as 10, 20, 30, 40, 50 mm, in two Greek cities Athens and Thessaloniki, during the period 1930-2007, are examined. The meteorological data, which concern daily rain totals (mm) and duration (h), were acquired from the National Observatory of Athens and from the meteorological station of the University of Thessaloniki. Our findings show that, in Athens, an increase in the number of annual rain days and the mean rain intensity over the aforementioned rain thresholds appears at the end of 1980’s and continues until nowadays. On the contrary, concerning Thessaloniki, a decrease in the rain days is apparent from 1980, while the decrease in the mean rain intensity concerns only the rain thresholds of 10 and 20 mm. This analysis reveals that extreme rain events are more frequent in Athens, which is under a high urbanization rhythm, than in Thessaloniki at the north of Greece. Finally, the patterns of the atmospheric circulation, which are associated with specific extreme cases are analysed, using NCEP reanalysis data.

  1. Mapping the Linguistic Landscape of Athens: The Case of Shop Signs (United States)

    Nikolaou, Alexander


    This paper focuses on the linguistic composition of commercial signs in the linguistic landscape (LL) of Athens, Greece. Previous studies have mainly been carried out in officially multilingual and multi-ethnic areas [Ben-Rafael, E., Shohamy, E., Amara, M. H., & Trumper-Hecht, N. (2006). "Linguistic landscape as symbolic construction of…

  2. We are an image from the future’: Reading back the Athens 2008 riots

    Directory of Open Access Journals (Sweden)

    Rosa Vasilaki


    Full Text Available On the 6th of December 2008, a police officer shot dead a teenager in Exarcheia, a central area in Athens. Within hours, the reactions turned into riots spreading across Athens. The Athens 2008 riots marked the beginning of the end of the years of affluence in Greece, which culminated symbolically with the 2004 Olympic Games. This paper proposes to read the December 2008 events back and ask to what extent these riots – symbolised by a graffiti on a wall in Athens saying ‘we are an image from the future’ - were a harbinger of the Greek crisis and of the generalised civil unrest which ensued and peaked between 2010-2012. With police data claiming that over 26,000 demonstrations have taken place across Greece since the December 2008 riots, civil unrest seems to have become endemic in the country, symptomatic of a crisis that is not only economic and social, but also political in the sense of the crisis of legitimacy of the State, its representatives and its institutions.

  3. Beyond the Informal City : Athens and the Possibility of an Urban Common

    NARCIS (Netherlands)

    Issaias, P.


    The thesis attempts to discuss the “informal” urbanization that characterizes the contemporary Greek cities as an immediate derivative of a complex political project, displayed primarily by architectural and urban typologies and protocols. As a case study, the Greek cities and particularly Athens,

  4. Ecotoxicological suitability of floodplain habitats in the Netherlands for the little owl (Athene noctua vidalli)

    NARCIS (Netherlands)

    Brink, van den N.W.; Groen, N.M.; Jonge, de J.; Bosveld, A.T.C.


    This study describes the actual risks of exposure to contaminants, which little owls (Athene noctua vidalli) face in Dutch river floodplains. The results indicate that PCBs pose a risk: not only are levels in little owls from floodplains higher than levels found in little owls from a reference site

  5. Multifunctional reactors

    NARCIS (Netherlands)

    Westerterp, K.R.


    Multifunctional reactors are single pieces of equipment in which, besides the reaction, other functions are carried out simultaneously. The other functions can be a heat, mass or momentum transfer operation and even another reaction. Multifunctional reactors are not new, but they have received much

  6. Discovery of a possible hybrid of the Critically Endangered Forest Owlet Athene blewitti and Spotted Owlet Athene brama (Aves: Strigiformes from northern Maharashtra, India

    Directory of Open Access Journals (Sweden)

    S.A. Pande


    Full Text Available The Forest Owlet Athene blewitti is considered to be critically endangered and at an extremely high risk of extinction. It was recently rediscovered after 113 years and little is known about this endemic species, which has a very limited distribution in central India. In early February 2004, the Earth Lovers Association (ELA and the International Birding and Research Centre in Eilat (IBRCE arranged an expedition to the Melghat Tiger Reserve (MTR and mapped all known and newly discovered territories of Forest and Spotted owlets (A. brama

  7. NUCLEAR REACTOR (United States)

    Miller, H.I.; Smith, R.C.


    This patent relates to nuclear reactors of the type which use a liquid fuel, such as a solution of uranyl sulfate in ordinary water which acts as the moderator. The reactor is comprised of a spherical vessel having a diameter of about 12 inches substantially surrounded by a reflector of beryllium oxide. Conventionnl control rods and safety rods are operated in slots in the reflector outside the vessel to control the operation of the reactor. An additional means for increasing the safety factor of the reactor by raising the ratio of delayed neutrons to prompt neutrons, is provided and consists of a soluble sulfate salt of beryllium dissolved in the liquid fuel in the proper proportion to obtain the result desired.

  8. NUCLEAR REACTOR (United States)

    Grebe, J.J.


    High temperature reactors which are uniquely adapted to serve as the heat source for nuclear pcwered rockets are described. The reactor is comprised essentially of an outer tubular heat resistant casing which provides the main coolant passageway to and away from the reactor core within the casing and in which the working fluid is preferably hydrogen or helium gas which is permitted to vaporize from a liquid storage tank. The reactor core has a generally spherical shape formed entirely of an active material comprised of fissile material and a moderator material which serves as a diluent. The active material is fabricated as a gas permeable porous material and is interlaced in a random manner with very small inter-connecting bores or capillary tubes through which the coolant gas may flow. The entire reactor is divided into successive sections along the direction of the temperature gradient or coolant flow, each section utilizing materials of construction which are most advantageous from a nuclear standpoint and which at the same time can withstand the operating temperature of that particular zone. This design results in a nuclear reactor characterized simultaneously by a minimum critiral size and mass and by the ability to heat a working fluid to an extremely high temperature.

  9. Comparison between satellite and instrumental solar irradiance data at the city of Athens, Greece (United States)

    Markonis, Yannis; Dimoulas, Thanos; Atalioti, Athina; Konstantinou, Charalampos; Kontini, Anna; Pipini, Magdalini-Io; Skarlatou, Eleni; Sarantopoulos, Vasilis; Tzouka, Katerina; Papalexiou, Simon; Koutsoyiannis, Demetris


    In this study, we examine and compare the statistical properties of satellite and instrumental solar irradiance data at the capital of Greece, Athens. Our aim is to determine whether satellite data are sufficient for the requirements of solar energy modelling applications. To this end we estimate the corresponding probability density functions, the auto-correlation functions and the parameters of some fitted simple stochastic models. We also investigate the effect of sample size to the variance in the temporal interpolation of daily time series. Finally, as an alternative, we examine if temperature can be used as a better predictor for the daily irradiance non-seasonal component instead of the satellite data. Acknowledgement: This research is conducted within the frame of the undergraduate course "Stochastic Methods in Water Resources" of the National Technical University of Athens (NTUA). The School of Civil Engineering of NTUA provided moral support for the participation of the students in the Assembly.

  10. The Depiction of Korčula on an Icon in the Byzantine Museum in Athens


    Demori Staničić, Zoraida


    The icon of Miracle by the Virgin attributed to the circle of Theodore Poulakis from Byzantine Museum in Athens is known and published. It is divided in two horizontal registers: the upper depicts Virgin Hodegetria with venerating angels under adorned pointed arch, while in the lower one there is a shipwreck in front of the fortified town. Virgin is accompanied by the eloquent epithet „The Hope of Sinners”. The wreck below this celestial scene is realistically presente...

  11. Estimating betas in thinner markets: "the case of the Athens Stock Exchange"


    Λαμπούσης, Αθανάσιος Ι.


    This paper examines the impact of the return interval on the beta estimate known as the “interval effect” which causes securities that are thinly traded to give biased OLS beta estimates. The present study covers a 5-year period, from January 2002 through to December 2006, using three different return intervals: daily, weekly and monthly data for 60 continuously listed thinly-traded stocks on the main market of the Athens Stock Exchange. Results generally support findings fr...

  12. Athens automation and control experiment project review meeting, Knoxville, Tennessee, December 3-5, 1985

    Energy Technology Data Exchange (ETDEWEB)

    Braithwait, S.D.; Broadaway, E.R.; Fortson, N.D.; Gellings, C.W.; Hu, P.S.; Lawler, J.S.; Markel, L.C.; McKinley, K.F.; Monteen, L.D.; Newton, B.K.


    The AACE is an electric power distribution automation project involving research and development of both hardware and software. Equipment for the project is being installed on the electric distribution system in Athens, Tennessee. Purposes of the AACE are to develop and test load control, volt/var control, and system reconfiguration capabilities on an electric distribution system and to transfer what is learned to the electric utility industry. Expected benefits include deferral of costly power generation plants and increased electric service reliability.

  13. The impact of sea breeze under different synoptic patterns on air pollution within Athens basin. (United States)

    Mavrakou, Thaleia; Philippopoulos, Kostas; Deligiorgi, Despina


    Air quality in densely populated urban coastal areas is directly related to the coupling of the synoptic and the local scale flows. The dispersion conditions within Athens basin, under the influence of different meteorological forcings, lead to distinct spatio-temporal air pollution patterns. The aim of the current observational research is to identify and examine the effect of sea breeze under different atmospheric circulation patterns on air pollution levels for a one-year study period (2007). The study employs surface pressure maps, routine meteorological observations at two coastal sites and nitrogen monoxide (NO), nitrogen dioxide (NO(2)) and ozone (O(3)) concentrations from a network of four air quality stations within the Athens basin. A three-step methodology is applied that incorporates a set of criteria for classifying atmospheric circulation and identifying sea breeze events under each circulation pattern. Two types of sea breeze development are identified (pure sea breeze-PSB and modified sea breeze-MSB) with distinct characteristics. Sea breeze is found to develop more frequently under offshore compared to onshore and parallel to the shoreline background flows. Poor dispersion conditions (high nitrogen oxides-NO(x) and O(3) concentrations) are connected to the pure sea breeze cases and to those cases where sea breeze interacts with a moderate northerly flow during the warm period. The levels of NO(x) and O(3) for the northern Athens basin area are found to be significantly higher during the sea breeze days compared to the Etesian days. Regarding the diurnal variation of ozone for the sea breeze days, peak concentrations and higher intra-daily ranges are observed. Day-to-day pollution accumulation (build-up effect) is measured for O(3) at the northern stations in the Athens basin. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Health promotion programs related to the Athens 2004 Olympic and Para Olympic games

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    Hadjichristodoulou Christos


    Full Text Available Abstract Background The Olympic Games constitute a first-class opportunity to promote athleticism and health messages. Little is known, however on the impact of Olympic Games on the development of health-promotion programs for the general population. Our objective was to identify and describe the population-based health-promotion programs implemented in relation to the Athens 2004 Olympic and Para Olympic Games. Methods A cross-sectional survey of all stakeholders of the Games, including the Athens 2004 Organizing Committee, all ministries of the Greek government, the National School of Public Health, all municipalities hosting Olympic events and all official private sponsors of the Games, was conducted after the conclusion of the Games. Results A total of 44 agencies were surveyed, 40 responded (91%, and ten (10 health-promotion programs were identified. Two programs were implemented by the Athens 2004 Organizing Committee, 2 from the Greek ministries, 2 from the National School of Public Health, 1 from municipalities, and 3 from official private sponsors of the Games. The total cost of the programs was estimated at 943,000 Euros; a relatively small fraction (0.08% of the overall cost of the Games. Conclusion Greece has made a small, however, significant step forward, on health promotion, in the context of the Olympic Games. The International Olympic Committee and the future hosting countries, including China, are encouraged to elaborate on this idea and offer the world a promising future for public health.

  15. Aerosol Monitoring over Athens Using Satellite and Ground-Based Measurements

    Directory of Open Access Journals (Sweden)

    D. G. Kaskaoutis


    Full Text Available Satellite data of moderate spatial resolution (MODIS and MERIS were used to retrieve the aerosol optical depth (AOD over the urban area of Athens. MODIS products were obtained at a horizontal resolution of 10 by 10 km2 centered over Athens, while the differential textural analysis (DTA code was applied to MERIS images to retrieve relative-to-reference AOD with a resolution of 260 m by 290 m. The possibility of exploiting the full resolution of MERIS data in retrieving AOD over a grid of a few hundreds metres was thereby investigated for the first time. MERIS-based AOD, centred at 560 nm, showed strong positive correlation to ground-based PM10 data (R2 = 0.85, while MODIS AOD products were in agreement with both MERIS and PM10. Back trajectories were used to study the impact of atmospheric conditions prevailing during the examined days. Days associated with Saharan air masses corresponded to enhanced AOD and predominance of coarse-mode particles. The results suggest that, at least for the case of Athens, AOD retrieved by MERIS images using the DTA code over cloud-free areas can be related to PM10. The accuracy of retrieval mainly depends on the successful selection of the reference satellite data, namely, an image being least contaminated by tropospheric aerosols.

  16. Impacts of air pollution and climate on materials in Athens, Greece (United States)

    Christodoulakis, John; Tzanis, Chris G.; Varotsos, Costas A.; Ferm, Martin; Tidblad, Johan


    For more than 10 years now the National and Kapodistrian University of Athens, Greece, has contributed to the UNECE (United Nations Economic Commission for Europe) ICP Materials (International Co-operative Programme on Effects on Materials including Historic and Cultural Monuments) programme for monitoring the corrosion/soiling levels of different kinds of materials due to environmental air-quality parameters. In this paper we present the results obtained from the analysis of observational data that were collected in Athens during the period 2003-2012. According to these results, the corrosion/soiling of the particular exposed materials tends to decrease over the years, except for the case of copper. Based on this long experimental database that is applicable to the multi-pollutant situation in the Athens basin, we present dose-response functions (DRFs) considering that dose stands for the air pollutant concentration, response for the material mass loss (normally per annum) and function, the relationship derived by the best statistical fit to the data.

  17. Impact of the 2009 Attica wild fires on the air quality in urban Athens (United States)

    Amiridis, V.; Zerefos, C.; Kazadzis, S.; Gerasopoulos, E.; Eleftheratos, K.; Vrekoussis, M.; Stohl, A.; Mamouri, R. E.; Kokkalis, P.; Papayannis, A.; Eleftheriadis, K.; Diapouli, E.; Keramitsoglou, I.; Kontoes, C.; Kotroni, V.; Lagouvardos, K.; Marinou, E.; Giannakaki, E.; Kostopoulou, E.; Giannakopoulos, C.; Richter, A.; Burrows, J. P.; Mihalopoulos, N.


    At the end of August 2009, wild fires ravaged the north-eastern fringes of Athens destroying invaluable forest wealth of the Greek capital. In this work, the impact of these fires on the air quality of Athens and surface radiation levels is examined. Satellite imagery, smoke dispersion modeling and meteorological data confirm the advection of smoke under cloud-free conditions over the city of Athens. Lidar measurements showed that the smoke plume dispersed in the free troposphere and lofted over the city reaching heights between 2 and 4 km. Ground-based sunphotometric measurements showed extreme aerosol optical depth, reaching nearly 6 in the UV wavelength range, accompanied by a reduction up to 70% of solar irradiance at ground. The intensive aerosol optical properties, namely the Ångström exponent, the lidar ratio, and the single scattering albedo, showed typical values for highly absorbing fresh smoke particles. In-situ air quality measurements revealed the impact of the smoke plume down to the surface with a slight delay on both the particulate and gaseous phase. Surface aerosols increase was encountered mainly in the fine mode with prominent elevation of OC and EC levels. Photochemical processes, studied via NO x titration of O 3, were also shown to be different compared to typical urban photochemistry.

  18. Multi-tracer approach to characterize domestic wood burning in Athens (Greece) during wintertime (United States)

    Fourtziou, L.; Liakakou, E.; Stavroulas, I.; Theodosi, C.; Zarmpas, P.; Psiloglou, B.; Sciare, J.; Maggos, T.; Bairachtari, K.; Bougiatioti, A.; Gerasopoulos, E.; Sarda-Estève, R.; Bonnaire, N.; Mihalopoulos, N.


    During the last years the atmosphere of the Great Athens Area (GAA) and other Greek cities is burdened from extended residential biomass burning for heating purposes. In this work, a series of near real-time and off-line biomass burning tracers are analyzed during intense wood burning events in Athens. The measurements were conducted at an urban background site located in the center of Athens, and in the heart of wood burning activities (winter 2013-2014). The measured tracers include high resolution measurements of non-sea salt potassium (nss-K+), wood burning black carbon (BCwb), the m/z 60 fragment associated with levoglucosan and monosaccharide anhydrides (levoglucosan, mannosan and galactosan) determined on selected filter samples. The suitability of these tracers was evaluated when the prevailing meteorological conditions with low dispersion and deposition mechanisms (low wind speed, absence of precipitation) were associated with high biomass burning emissions at nighttime. During the severe smog periods, the levels of K+, BCwb, m/z 60 and levoglucosan were up to 2.2 μg m-3, 12.5 μg m-3, 3.4 μg m-3 and 8.6 μg m-3, respectively, higher by a factor of at least two, relatively to the non smog periods due to biomass burning. Correlations between biomass burning tracers as well as between monosaccharide anhydrides provided information about the type of material and wood being burned.

  19. 1950s Athens as Palimpsest: A BBC Radio Play by Louis MacNeice

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    Konstantina Georganta


    Full Text Available Louis MacNeice’s Portrait of Athens, a radio play broadcast by the BBC in November 1951, came at a time of reconstruction throughout Europe but also at a time when the world was on the verge of yet another war. In it we find the city’s bones, Athens of Thucydides, Demosthenes, Pericles and Socrates, but also a modern city where you could hear street cries, radio tunes and trams and visit both Kolonaki and the district of New Smyrna where Asia Minor refugees had settled almost thirty years earlier. Twenty-four centuries were transposed to twenty-four hours and twenty-four hours squeezed into the space of one with the play focusing on questions of memory, identity, and lived or remembered traumas. What the audience got as a result was a representation of the varied layers that made up modern Athens, a portrait of the city as palimpsest in contrast to other accounts of the same period where the past dominated over the present making the latter non visible.

  20. Reactor Neutrinos

    CERN Document Server

    Lasserre, T; Lasserre, Thierry; Sobel, Henry W.


    We review the status and the results of reactor neutrino experiments, that toe the cutting edge of neutrino research. Short baseline experiments have provided the measurement of the reactor neutrino spectrum, and are still searching for important phenomena such as the neutrino magnetic moment. They could open the door to the measurement of coherent neutrino scattering in a near future. Middle and long baseline oscillation experiments at Chooz and KamLAND have played a relevant role in neutrino oscillation physics in the last years. It is now widely accepted that a new middle baseline disappearance reactor neutrino experiment with multiple detectors could provide a clean measurement of the last undetermined neutrino mixing angle theta13. We conclude by opening on possible use of neutrinos for Society: NonProliferation of Nuclear materials and Geophysics.

  1. NEUTRONIC REACTORS (United States)

    Wigner, E.P.; Young, G.J.


    A method is presented for loading and unloading rod type fuel elements of a neutronic reactor of the heterogeneous, solld moderator, liquid cooled type. In the embodiment illustrated, the fuel rods are disposed in vertical coolant channels in the reactor core. The fuel rods are loaded and unloaded through the upper openings of the channels which are immersed in the coolant liquid, such as water. Unloading is accomplished by means of a coffer dam assembly having an outer sleeve which is placed in sealing relation around the upper opening. A radiation shield sleeve is disposed in and reciprocable through the coffer dam sleeve. A fuel rod engaging member operates through the axial bore in the radiation shield sleeve to withdraw the fuel rod from its position in the reactor coolant channel into the shield, the shield snd rod then being removed. Loading is accomplished in the reverse procedure.

  2. Neutronic reactor (United States)

    Wende, Charles W. J.; Babcock, Dale F.; Menegus, Robert L.


    A nuclear reactor includes an active portion with fissionable fuel and neutron moderating material surrounded by neutron reflecting material. A control element in the active portion includes a group of movable rods constructed of neutron-absorbing material. Each rod is movable with respect to the other rods to vary the absorption of neutrons and effect control over neutron flux.

  3. Neutronic reactor

    Energy Technology Data Exchange (ETDEWEB)

    Babcock, D.F.; Menegus, R.L.; Wende, C.W.


    A nuclear reactor includes an active portion with fissionable fuel and neutron moderating material surrounded by neutron reflecting material. A control element in the active portion includes a group of movable rods constructed of neutron-absorbing material. Each rod is movable with respect to the other rods to vary the absorption of neutrons and effect control over neutron flux.

  4. Indications of correlation between gravity measurements and isoseismal maps. A case study of Athens basin (Greece) (United States)

    Dilalos, S.; Alexopoulos, J. D.


    In this paper, we discuss the correlation between isoseismal contour maps and gravity residual anomaly maps and how it might contribute to the characterization of vulnerable areas to earthquake damage, especially in urban areas, where the geophysical data collection is difficult. More specifically, we compare a couple of isoseismal maps that have been produced and published after the catastrophic earthquake of 7th September 1999 (5.9R) in Athens, the metropolis of Greece, with the residual map produced from the processing and data reduction of a gravity survey that has been carried out in the Athens basin recently. The geologic and tectonic regime of the Athens basin is quite complicated and it is still being updated with new elements. Basically it is comprised of four different geotectonic units, one of them considered as the autochthon. During the gravity investigation, 807 gravity stations were collected, based on a grid plan with spacing almost 1 km, covering the entire basin and supported by a newly established gravity base network comprised by thirteen bases. Differential DGPS technique was used for the accurate measurement of all the gravity stations and bases coordinates. After the appropriate data reduction and the construction of the Complete Bouguer Anomaly map, we applied FFT filtering in order to remove the regional component and produce the Residual Anomaly Map. The comparison of the Residual Anomaly Map with the isoseismal contours revealed that the areas with the most damage because of the earthquake were located in the areas with the minimum values of the Residual Anomaly Map.

  5. Outdoor particulate matter and childhood asthma admissions in Athens, Greece: a time-series study

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    Roma Eleftheria S


    Full Text Available Abstract Background Particulate matter with diameter less than 10 micrometers (PM10 that originates from anthropogenic activities and natural sources may settle in the bronchi and cause adverse effects possibly via oxidative stress in susceptible individuals, such as asthmatic children. This study aimed to investigate the effect of outdoor PM10 concentrations on childhood asthma admissions (CAA in Athens, Greece. Methods Daily counts of CAA from the three Children's Hospitals within the greater Athens' area were obtained from the hospital records during a four-year period (2001-2004, n = 3602 children. Mean daily PM10 concentrations recorded by the air pollution-monitoring network of the greater Athens area were also collected. The relationship between CAA and PM10 concentrations was investigated using the Generalized Linear Models with Poisson distribution and logistic analysis. Results There was a statistically significant (95% CL relationship between CAA and mean daily PM10 concentrations on the day of exposure (+3.8% for 10 μg/m3 increase in PM10 concentrations, while a 1-day lag (+3.4% for 10 μg/m3 increase in PM10 concentrations and a 4-day lag (+4.3% for 10 μg/m3 increase in PM10 concentrations were observed for older asthmatic children (5-14 year-old. High mean daily PM10 concentration (the highest 10%; >65.69 μg/m3 doubled the risk of asthma exacerbations even in younger asthmatic children (0-4 year-old. Conclusions Our results provide evidence of the adverse effect of PM10 on the rates of paediatric asthma exacerbations and hospital admissions. A four-day lag effect between PM10 peak exposure and asthma admissions was also observed in the older age group.

  6. Epicurus and Athens: the creation of an identity community different from the polis

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    José PASCUAL


    Full Text Available This paper intends to demonstrate that Epicurus’ life was influenced by the political facts that Athens went through during the period from 341 to 267 B.C. And also that through the analysis of Epicurus’ critics to the three elements that support the polis , especially the Athenian polis, the paideia, the participation in the political life and the religion of the polis, it tries to prove that the philosopher constituted a different community from the civic one which identity signs where far away from those of the polis.

  7. The Church of Kapnikarea in Athens: Remarks on its history, typology and form

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    Gkioles Nikolaos


    Full Text Available This article offers a detailed presentation of the Athens church of the Mother of God, known by the name of Kapnikarea, which originates from the middle of the Byzantine period. Initially, the Kapnikarea was the katholikon of the monastery but today it is a building complex, consisting of three chronologically different ensembles. They are the Church of the Presentation of the Virgin, erected just after the mid-11th century, the exonarthex probably dating from the beginning of the 12th century, and the smaller northern church dedicated to St. Barbara, built during the Ottoman epoch.

  8. Commuters’ Personal Exposure to Ambient and Indoor Ozone in Athens, Greece

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    Krystallia K. Kalimeri


    Full Text Available This pilot study aimed to monitor the residential/office indoor, outdoor, and personal levels of ozone for people living, working, and commuting in Athens, Greece. Participants (16 persons of this study worked at the same place. Passive sampling analysis results did not indicate any limit exceedance (Directive 2008/50/EC: 120 µg/m3, World Health Organization (WHO Air Quality Guidelines 2005: 100 µg/m3. The highest “house-outdoor” concentration was noticed for participants living in the north suburbs of Athens, confirming the photochemical ozone formation at the northern parts of the basin during southwestern prevailing winds. The residential indoor to outdoor ratio (I/O was found to be significantly lower than unity, underlying the outdoor originality of the pollutant. The highest “office-indoor” concentration was observed in a ground-level building, characterized by the extensive use of photocopy machines and printers. Personal ozone levels were positively correlated only with indoor-office concentrations. A clear correlation of personal ozone levels to the time spent by the individuals during moving/staying outdoors was observed. On the other hand, no correlation was observed when focusing only on commuting time, due to the fact that transit time includes both on-foot and in-vehicle time periods, therefore activities associated with increased exposure levels, but also with pollutants removal by recirculating air filtering systems, respectively.

  9. The use of nutritional supplements among recreational athletes in Athens, Greece. (United States)

    Tsitsimpikou, Christina; Chrisostomou, Nastasia; Papalexis, Peter; Tsarouhas, Konstantinos; Tsatsakis, Aristidis; Jamurtas, Athanasios


    Although the use of nutritional supplements by professional athletes and the benefits thereof have been extensively studied, information on recreational athletes' use of supplements is limited. This study investigated the consumption of nutritional supplements, source of information and supply of supplements, and level of awareness with regard to the relevant legislation among individuals who undertake regular exercise in Athens, Greece. A closed-ended, anonymous questionnaire was answered by 329 subjects (180 men, 149 women), age 30.6 ± 12.1 yr, from 11 randomly selected gym centers. Preparations declared as anabolic agents by the users were submitted to a gas chromatographic analyzer coupled to a mass spectrometric detector. Consumption of nutritional supplements was reported by 41% of the study population, with proteins/amino acids and vitamins being the most popular. Age (r = .456, p = .035), sex (χ2 = 14.1, df = 1, p steroids not stated on the label. In conclusion, use of nutritional supplements was common among recreational athletes in Athens, Greece. A low level of awareness and low involvement of health care professionals as sources of information and supply were observed.

  10. The December revolt in Athens British intervention and Yugoslav reaction: December 1944 - January 1945

    Directory of Open Access Journals (Sweden)

    Ristović Milan


    Full Text Available The revolt that members and supporters of the leftist movement EAM-ELAS staged in Athens in early December 1944 against the Greek royal and British forces ushered into the second "round" of the civil war in Greece. The developments in the neighborhood draw much attention in Yugoslavia, where the war of liberation was in its final phases in parallel with the elimination of political rivals to the new government in which communists played a central role. This attention was not only a result of ideological solidarity, it also had to do with the "Macedonian Question", i.e. the position of Slavic Macedonian minority in northern Greece, an issue that had aroused a debate between Greek and Yugoslav communists in 1944. Difficulties in relations between the Yugoslav partisan leadership and the British, pressure from London, the passivity of the Soviet Union as regards the developments in Athens, a stalemate on the Srem Front, fights with the remaining collaborationist forces, compelled Yugoslavia to take a reserved position and avoid direct involvement in Greece. Appeals of Greek communists for aid in military supplies, promised on the eve of the revolt, failed to provoke a tangible response of the Yugoslav leadership. Once the revolt was crushed by the British and a truce between the EAM-ELAS and the royal government signed a wave of migration to Yugoslavia ensued of the borderland civilian Slavic Macedonian population but also of several thousand radical Greek leftists unwilling to accept the Varkiza agreement.

  11. Security rules and banned items in psychiatric acute admission wards in Athens, Greece. (United States)

    Koukia, Evmorfia; Giannouli, Eleni; Gonis, Nikolaos; Douzenis, Athanassios


    Mental health nurses play a key role in maintaining the safety of patients, themselves, and others during hospitalization. The aim of the research was to evaluate the safety measures that are taken by mental health nurses to identify the security policies that exist in acute mental health wards. The Ward Safety and Security Rules Survey was used as a method of data collection. Descriptive analysis and content analysis were carried out in order to identify nurses' practices. The total sample consisted of 172 mental health nurses and nurses' assistants who worked in 14 acute inpatient psychiatric wards in three psychiatric hospitals in the greater area of Athens, Greece. The results show a minimum number of security features existing in the wards. Only one of the 14 wards had an intercom system. In only nine wards, there was a panic alarm in the office, and in eight, an emergency response telephone extension. A wide range of practices were noted concerning banned items and patient searches upon admission and return from leave. The results indicate the significant lack of protocols and specific safety rules to guide nurses' actions across psychiatric acute admission wards in Athens. © 2010 The Authors. International Journal of Mental Health Nursing © 2010 Australian College of Mental Health Nurses Inc.

  12. Athens automation and control experiment project review meeting, Dallas, Texas, December 5-6, 1984

    Energy Technology Data Exchange (ETDEWEB)

    Detwiler, J.S.; Hu, P.S.; Lawler, J.S.; Markel, L.C.; McIntyre, J.M.; McKinley, K.F.; Monteen, L.D.; Purucker, S.L.; Reed, J.H.; Rizy, D.T.


    The AACE is an electric power distribution automation project involving research and development of both hardware and software. Equipment for the project is being installed on the electric distribution system of the Athens Utilities Board (AUB), located in Athens, Tennessee. Purposes of the AACE are to develop and test load control, volt/var control, and system reconfiguration capabilities on an electric distribution system and to transfer what is learned to the electric utility industry. Expected benefits include deferral of costly power generation plants and increased electric service reliability. A project review meeting was held to review the progress of the AACE and to communicate the objectives and experimental plans to the electric utility industry. At the time of the meeting, the experimental test plans were being written; much of the AACE field equipment had been received by AUB, and installation had begun. A computer system, the AACE Test System (AACETS), was already operational at ORNL. AACETS will be used to develop and test applications software and experimental control strategies prior to their implementation on the AUB system. The AACE experiments are scheduled to begin in October 1985 and to continue through October 1987.

  13. Spatial distribution of PM1 and PM10 during Saharan dust episodes in Athens, Greece

    Directory of Open Access Journals (Sweden)

    G. Ferentinos


    Full Text Available The objective of this study is to present and analyse the spatial distribution of PM1 (particulate matter with diameter less than 1 μm and PM10 (particulate matter with diameter less than 10 μm within the greater area of Athens (GAA, Greece, during two extreme Saharan dust episodes in 2006 and 2008. Two portable detectors, based on light scattering method, were used to record the particulate matter concentrations. The samples were collected in the same morning hour of the day which coincided with the peak of vehicles traffic. We analysed the recorded data on normal days and on days with extreme Saharan dust events in order to find out the exceedances of the particulate matter concentrations. Using Kriging method, the spatial patterns of PM1 and PM10 concentrations were constructed for GAA. It is already known that particulate matter represent the main hazard in cardiovascular and respiratory syndromes within the most polluted cities of Europe, which confront high traffic problems, amplified by Saharan dust episodes, which are frequent especially in the Southern Europe, during spring time. The results of the performed analysis showed that during these episodes, PM concentrations over exceed the thresholds set by the European Union, exacerbating the human health in Athens.

  14. Nuclear Reactors. Revised. (United States)

    Hogerton, John F.

    This publication is one of a series of information booklets for the general public published by the United States Atomic Energy Commission. Among the topics discussed are: How Reactors Work; Reactor Design; Research, Teaching, and Materials Testing; Reactors (Research, Teaching and Materials); Production Reactors; Reactors for Electric Power…

  15. Monitoring of Air Quality in Passenger Cabins of the Athens Metro (United States)

    Tsairidi, Evangelia; Assimakopoulos, Vasiliki D.; Assimakopoulos, Margarita-Niki; Barbaresos, Nicolaos; Karagiannis, Athanassios


    The air pollution induced by various transportation means combines the emission of pollutants with the simultaneous presence of people. In this respect, the scientific community has focused its efforts in studying both the air quality within busy streets and inside cars, buses and the underground railway network in order to identify the pollutants' sources and levels as well as the human exposure. The impact of the air pollution on commuters of the underground may be more severe because it is a confined space, extended mostly under heavily trafficked urban streets, relies on mechanical ventilation for air renewal and gathers big numbers of passengers. The purpose of the present work is to monitor the air quality of the city of Athens Metro Network cabins and platforms during the unusually hot summer of 2012. For that cause particulate matter (PM10, PM2.5, PM1), carbon dioxide (CO2), the number of commuters along with temperature (T) and humidity (RH) were recorded inside the Athens Metro Blue Line trains (covering a route from the centre of Athens (Aigaleo) to the Athens International Airport) and on the platforms of a central (Syntagma) and a suburban-traffic (Doukissis Plakentias) station between June and August. The data collection included six different experiments that took place for 2 consecutive working days each, for a time period of 6 weeks from 6:30 am too 7:00 pm in order to account for different outdoor climatic conditions and for morning and evening rush hours respectively. Measurements were taken in the middle car of the moving trains and the platform end of the selected stations. The results show PM concentrations to be higher (approximately 2 to 5 times) inside the cabins and o the platforms of the underground network as compared to the outdoor levels monitored routinely by the Ministry of Environment. Moreover, PM1, PM2.5 and PM10 average concentrations recorded at the Syntagma Station Platform were almost constantly higher reaching 11 μg m-3 47

  16. Photocatalytic reactor (United States)

    Bischoff, Brian L.; Fain, Douglas E.; Stockdale, John A. D.


    A photocatalytic reactor for processing selected reactants from a fluid medium comprising at least one permeable photocatalytic membrane having a photocatalytic material. The material forms an area of chemically active sites when illuminated by light at selected wavelengths. When the fluid medium is passed through the illuminated membrane, the reactants are processed at these sites separating the processed fluid from the unprocessed fluid. A light source is provided and a light transmitting means, including an optical fiber, for transmitting light from the light source to the membrane.

  17. Hybrid adsorptive membrane reactor

    Energy Technology Data Exchange (ETDEWEB)

    Tsotsis, Theodore T [Huntington Beach, CA; Sahimi, Muhammad [Altadena, CA; Fayyaz-Najafi, Babak [Richmond, CA; Harale, Aadesh [Los Angeles, CA; Park, Byoung-Gi [Yeosu, KR; Liu, Paul K. T. [Lafayette Hill, PA


    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  18. D and DR Reactors (United States)

    Federal Laboratory Consortium — The world's second full-scale nuclear reactor was the D Reactor at Hanford which was built in the early 1940's and went operational in December of 1944.D Reactor ran...

  19. Reactor transient

    Energy Technology Data Exchange (ETDEWEB)

    Menegus, R.L.


    The authors are planning a calculation to be done on the Univac at the Louviers Building to estimate the effect of xenon transients, a high reactor power. This memorandum outlines the reasons why they prefer to do the work at Louviers rather than at another location, such as N.Y.U. They are to calculate the response of the reactor to a sudden change in position of the half rods. Qualitatively, the response will be a change in the rooftop ratio of the neutron flux. The rooftop ratio may oscillate with high damping, or, instead, it may oscillate for many cycles. It has not been possible for them to determine this response by hand calculation because of the complexity of the problem, and yet it is important for them to be certain that high power operation will not lead us to inherently unstable operation. Therefore they have resorted to machine computation. The system of differential equations that describes the response has seven dependent variables; therefore there are seven equations, each coupled with one or more of the others. The authors have discussed the problem with R.R. Haefner at the plant, and it is his opinion that the IBM 650 cannot adequately handle the system of seven equations because the characteristic time constants vary over a range of about 10{sup 8}. The Univac located at the Louviers Building is said to be satisfactory for this computation.

  20. Contribution of wood combustion in winter submicron ambient aerosols over Athens (United States)

    Stavroulas, Iasonas; Fourtziou, Luciana; Zarmpas, Pavlos; Bougiatioti, Aikaterini; Liakakou, Eleni; Sciare, Jean; Mihalopoulos, Nikos


    Given that a smog pollution problem, mostly attributed to wood burning in fireplaces and stoves, is currently emerging in the Athens metropolitan area, several monitoring instruments were deployed at the National Observatory of Athens facilities in the region of Thissio, downtown Athens . These included an Aerodyne Aerosol Chemical Speciation Monitor with 30 minute time resolution and a Particle Into Liquid Sampler coupled with Ion Chromatography with 15 minute time resolution. The campaign duration was from December 2013 to February 2014 and the aim was to investigate the chemical composition of ultrafine aerosols connected to biomass burning.. Many events of high particulate matter concentrations (exceeding the 50 μg/m3 daily limit) were observed during night-time, with maximum concentrations occurring when stagnant atmospheric conditions prevailed. Potassium measured by the PILS - IC, and the m/z = 60 fragment measured by the ACSM, was initially used as a tracer of biomass burning events. A good correlation was determined for those two factors, allowing for safe conclusions concerning the identification of these aforementioned biomass burning events. For utmost certainty, Black Carbon measurements coming from three different instruments, was also used. As a second step, Positive Matrix Factorization analysis was performed, using the SoFi interface, which utilizes the generalized multilinear engine (ME-2) (Canonaco et Al., Atmos. Meas. Tech., 6, 3649-3661, 2013), for the source apportionment of the organic particulate matter, determined by the ACSM. This analysis revealed a very important Biomass Burning Organic Aerosol (BBOA) factor with a clear diurnal cycle, showing maxima in the time interval from 21:00 in the evening to 02:00 in the morning. A Hydrocarbon-like Organic Aerosol (HOA) factor is also present with a maximum during the same time interval, attributed to fossil fuel used in central heating systems, and a secondary maximum during the day, attributed

  1. The problem of seismic potential assessment: Case study of the unexpected earthquake of 7 September 1999 in Athens, Greece (United States)

    Papadopoulos, G. A.; Ganas, A.; Pavlides, S.


    Lessons learned form the disastrous earthquake (MW = 5.9) that hit the metropolitan area of Athens, Greece, on 7 September 1999, are examined particularly as for the seismic potential considered before the earthquake occurrence. A general belief was created in the past decades that the seismic potential in Athens was very low. Fault plane solutions of the 1999 shock indicate that it was associated with a normal fault trending WNW-ESE and dipping to SW. Field geological observations conducted after the event in the Fili neotectonic fault, situated at 15-20 km to the north of Athens, imply that it has possibly been the seismogenic structure of the main rupture, and that it reactivated in very recent geological times. Archaeoseismological observations performed in the ancient Fili Fort, revealed repaired structural damage that was very likely caused by an earthquake occurring in palaeochristianic or Byzantine times. From a new catalogue of historical earthquakes it results that the main events of 1705, 1805 and 1889 could be tentatively located within a distance of ~30 km from Athens although the little macroseismic information available makes their locations quite uncertain. During the instrumental period of observation, only few small shocks were recorded in the Athens region. It is obvious that should a research effort had been undertaken before the 1999 earthquake, certainly it would be concluded that at least one strong earthquake took place in historical times in the broad region affected in 1999, and that the Fili fault is active and is capable to produce strong shocks in the future. However, such a study was never conducted by the scientific community beforehand.

  2. Nuclear reactor neutron shielding (United States)

    Speaker, Daniel P; Neeley, Gary W; Inman, James B


    A nuclear reactor includes a reactor pressure vessel and a nuclear reactor core comprising fissile material disposed in a lower portion of the reactor pressure vessel. The lower portion of the reactor pressure vessel is disposed in a reactor cavity. An annular neutron stop is located at an elevation above the uppermost elevation of the nuclear reactor core. The annular neutron stop comprises neutron absorbing material filling an annular gap between the reactor pressure vessel and the wall of the reactor cavity. The annular neutron stop may comprise an outer neutron stop ring attached to the wall of the reactor cavity, and an inner neutron stop ring attached to the reactor pressure vessel. An excore instrument guide tube penetrates through the annular neutron stop, and a neutron plug comprising neutron absorbing material is disposed in the tube at the penetration through the neutron stop.

  3. Can we speak of a "state patronage"? Liturgies and misthophoria in classical Athens

    Directory of Open Access Journals (Sweden)

    Mariano José Requena


    Full Text Available This paper intends to discuss the characterization of certain practices of patronage in classical Athens as forms of "state patronage". The definition of the polis as a state may be questioned. The political relations of democracy, expression of the demos power, did not allow the exclusive monopoly of coercion. Consequently, there was no separation between civil society and political society, nor was there a political apparatus that was distinguished in its exercise upon those who are the sovereign body. Thus the existence of patronage relationships seems to fall in tension between the mechanisms of reciprocity and redistribution that the elite members usufruct as a way to acquire prestige and political support within their community, and people’s demands, who can implement them in their favor

  4. [The Codex of the Laboratory of Pharmacognosy of the University of Athens, Part. I]. (United States)

    Philianos, Skevos; Skaltsa, Hélène


    This work concerns the first part of a manuscript written in the 18th century and stored in the Laboratory of Pharmacognosy of the University of Athens. This part includes an introduction based on the theories of Hippocrates and Galen concerning the four humors: blood, phlegm, yellow bile and black bile, which should be in balance. During the seasons and depending of the age, these humors are converted to each other. Blood increases in the spring and in children, phlegm is growing in winter and in old man, yellow bile in adulthood and black bile in the fall and the third age. The disease is due to the increase or decrease in these fluids. Many formulas with purgative and cholagogue effects are described for each humor. The chapter ends with advice on the necessary diet, hygiene and lifestyle to keep health care.

  5. The impact of IFRS on ratios of listed and new listed companies of Athens Exchange

    Directory of Open Access Journals (Sweden)

    Balios Dimitrios


    Full Text Available In this study we are researching the effect of the implementation of International Financial Reporting Standards (IFRS on financial ratios of listed companies of Athens Exchange (AE. Emphasis is given to the differences between Greek Accounting Standards (GAS and IFRS and their impact on the calculation of financial ratios which are based on financial statements prepared in accordance with the first or the second accounting standard. Therefore, the study was applied to two samples of companies. The first sample includes companies that have been listed in AE for years and the second sample includes companies that have recently been listed in AE. Considering the particular characteristics of each group of companies, we are examining the probability of quantitative differentiations in financial ratios due to the transition from the one accounting standard to the other. The results of the research results showed that both samples of companies, when not influenced by other factors, do not have significant differences in their behavior.

  6. Tracking movements of Athene owls: the application of North American experiences to Europe

    Directory of Open Access Journals (Sweden)

    Holroyd, G. L.


    Full Text Available Migration and dispersal are important ecological and evolutionary processes and understanding them is a requirement for species conservation efforts. Burrowing owl, Athene cunicularia, the North American equivalent of little owl, A. noctua, is migratory in the northern parts of its range. In Canada their populations have declined dramatically and are classified as endangered. Movements of burrowing owls have been studied using banding (ringing, VHF telemetry, stable isotopes, genetics (DNA, geolocators and satellite transmitters. Geolocators and satellite transmitters provide the most reliable information about migrations but to operate successfully they are both dependent upon exposure to sunlight, which can be limited for nocturnal owls. Ringing encounters and winter influxes of little owls into Spain, including the Balearic Islands, indicate that some migration movement may be occurring. A stable isotope study could determine if wintering owls in southern Europe includes owls originating in northern Europe.

  7. Genetic consequences of population decline in the Danish population of the little owl (Athene noctua)

    DEFF Research Database (Denmark)

    Pertoldi, Cino; Pellegrino, Irene; Cucco, Maroc


    Background: Danish populations of the little owl (Athene noctua) have experienced dramaticdeclines in size over the past century. Before 1960 the little owl population was abundantin Denmark (estimated N>2000), but between 1960 and 1980 the population declinedrapidly, and since 1980 the little owl...... population has survived only in small and fragmentedareas. Question: Is the decline in population size associated with reduced genetic variation in theseDanish populations of the little owl? Are the populations genetically fragmented?Field site: Samples were collected from birds in Denmark (from 57457″N...... relatively little genetic variability, with more recent onesshowing even less. In addition, pairwise FST values showed evidence for genetic substructuringwith small but significant genetic differences between the extant population and the extinct owlpopulations on the Danish isle of Funen. The modest loss...

  8. Virtual Visit to the ATLAS Control Room by Filothei Lyceum, Athens

    CERN Multimedia

    ATLAS Experiment


    For us, to connect with the ATLAS experiment is a great opportunity to inspire our students towards physics. Our students are thrilled in the prospective of talking with one of the members of the experiment, that also was a student of our school, and connect with the place that the data are recorded and the search of new physics is taking place. Already they have a lot of questions that they want to ask. They want to discover how scientists at CERN are all looking back through deep time to answer those big questions on the origins of life, the universe and everything and in what way the ATLAS experiment is involved in.

  9. The behaviour of ozone and peroxyacetyl nitrate concentrations for different wind regimes during the MEDCAPHOT-TRACE campaign in the greater area of Athens, Greece

    DEFF Research Database (Denmark)

    Suppan, P.; Fabian, P.; Vyras, L.


    As a part of an international experimental field campaign, the association of air pollution with sea breeze circulation in the Greater Athens Area (GAA) is discussed on the basis of the behaviour of ozone and peroxyacetyl nitrate (PAN). During typical sea breeze days inside the Athens basin...... a straight line across the Athens basin ranging From the island of Aegina in the Gulf of Saronikos to the northern border of the GAA show distinct peaks due to the pollution cloud NEPHOS. (C) 1998 Published by Elsevier Science Ltd. All rights reserved....

  10. Past, present and future of passive homes in solar village 3, Athens (United States)

    Kalogridis, Achilles

    Solar village 3 in Pefki, Athens, was part of an ambitious program for the promotion of solar technology, applied to a large scale social housing scheme, designed in mid 80's and firstly inhabited in the early 1990's. Among the aims of the project was the demonstration of the latest of technology in active solar systems and passive techniques, incorporated in a new settlement's layout and houses' building envelop, in order to create an energy saving, comfortable environment. More than fifteen years later, the housing complex remains the largest residential development of bioclimatic "solar" architecture in Athens, with the active and passive solar systems providing space and water heating for about 1750 inhabitants. The study focuses in the passive solar systems that have been applied to a number of the buildings of the settlement. The systems provide space heating with no need of any active mechanism, however with demand of the participation of the end users for their proper operation. The essay reviews various previous studies, monitoring reports and criticisms that have appeared throughout the past years, and identifies how the houses perform today, through a recent survey, sample monitoring and thermal comfort simulation. The report records things that have changed, features which worked well or others that did not and comments on the residents' behaviour. Interesting findings come into question, regarding the passive solar systems, their integration into the building's design, their current condition and their contribution to energy savings and thermal comfort conditions. Finally, current plans concerning the future of the settlement are highlighted, and considerations about the houses sustainability are suggested.

  11. Exorcising the nightmare of reactor meltdowns. First of four articles

    Energy Technology Data Exchange (ETDEWEB)

    Faltermayer, E.


    Facts on the hazards of reactors are investigated in this first article of four on that subject. Some knowledgeable critics warn that a serious nuclear disaster is a real possibility within the next few decades. Other experts, mostly in the nuclear industry, counter that fission power is just another engineering challenge that has been met by a society that copes with many others. Each year, they note, U.S. industry handles enough chlorine to kill the entire human race 100,000 times over. U.S. utilities have accumulated 440 reactor-years of experience with nonbreeeding reactors with no meltdowns. Beginning in 1972, a study (eventually report WASH-1400) was made of hundreds of sequences of things that could go wrong in commercial reactors, including human error, and estimated the amounts of radioactivity that could be released in each sequence under varying weather conditions; the optimistic analyses in that report are well known. In January 1979, the Nuclear Regulatory Commission issued a statement saying that it does not regard as reliable WASH-1400's figures on the overall risk of reactor accidents. In March 1975, some 1,600 electrical cables were burned in a seven-hour fire at Brown's Ferry nuclear plant near Athens, Alabama with no major accident occurring. .The LOFT reactor experiment in Idaho is described. Pipe cracks are the most worrisome problem, but these get discovered and corrected before an accident occurs. In a society that long ago lost its technological innocence, and that lives with far greater hazards both natural and manmade, nuclear power causes more unease that it should. (MCW)

  12. The establishment of the Metropolis of Patras and of Athens and the Slavs of the Peloponnesus

    Directory of Open Access Journals (Sweden)

    Komatina Predrag


    Full Text Available By the end of the 8th century, after the expedition of 783 led by Staurakios the imperial forces began the reestablishing of the imperial control over those parts of the Peloponnesus which had previously been in the hands of independent Slavs for about 200 years. The result was the administrative reorganization of the whole of the peninsula. The administrative reorganization was followed by the ecclesiastical one. Thus, in the so-called Notitia 2, written after 805/806 and before the end of 814, we find an entirely new image of the ecclesiastical organization of that part of the Empire. Alongside the old Metropolis of Corinth, there are now two new metropolitan sees - that of Patras and that of Athens. The Metropolis of Patras was founded by the charter of the emperor Nikephoros I, between 1st november 805 and 25th february 806. But, the Church of Patras already existed even before that moment, as an autocephalous archbishopric, subordinated directly to the patriarchical throne of Constantinople, and its existence in that rank was attested as early as 787. The Metropolis of Athens was established sometime during that same period, in the reign of patriarch Tarasios, but after the Council of 787, so the date of its establishment could be placed between 787 and 806. Like the Church of Patras, the Church of Athens also had the rank of autocephalous archbishopric, subordinated directly to Constantinople, before it was elevated to the rank of metropolis. It is not certain when the Church of Athens received the rank of autocephalous archbishopric. What were reasons for the creation of these new metropolitan sees within the old province of the Metropolis of Corinth? The ancient Metropolis of Corinth was the ecclesiastical center of the ancient province of Achaia, which in the later Roman times covered all of the Peloponnesus and Central Greece. But, the province of Achaia existed no more and so the rights and claims of the See of Corinth lost their

  13. New record of Pelecitus sp. (Nematoda, Onchocercidae) as a parasite of Athene cunicularia (Strigiformes, Strigidae) in southeastern Brazil. (United States)

    Silva, Tarcísio Macedo; Okamoto, Adriano Sakai; Silva, Lidiane Aparecida Firmino da; Smaniotto, Bruna Domeneghetti; Silva, Reinaldo José da; Andreatti Filho, Raphael Lucio


    The aim of this study was to report the burrowing owl Athene cunicularia as a new host for the filarid nematode Pelecitus sp. in southeastern Brazil for the first time, as well as reporting the occurrence of this nematode species in the body cavity, near the cervical air sac and lung region. This study contributes towards knowledge of parasitism in Brazilian wild birds and an anatomical region of the host as an infection site for Pelecitus sp.

  14. New record of Pelecitus sp. (Nematoda, Onchocercidae as a parasite of Athene cunicularia (Strigiformes, Strigidae in southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Tarcísio Macedo Silva

    Full Text Available The aim of this study was to report the burrowing owl Athene cunicularia as a new host for the filarid nematode Pelecitus sp. in southeastern Brazil for the first time, as well as reporting the occurrence of this nematode species in the body cavity, near the cervical air sac and lung region. This study contributes towards knowledge of parasitism in Brazilian wild birds and an anatomical region of the host as an infection site for Pelecitus sp.

  15. Seasonal differences in thermal sensation in the outdoor urban environment of Mediterranean climates – The example of Athens, Greece


    Tseliou, Areti; Tsiros, Ioannis; Nikolopoulou, Marialena


    Outdoor urban areas are very important for cities and microclimate is a critical parameter in the design process, contributing to thermal comfort which is important for urban developments. The research presented in this paper is part of extensive field surveys conducted in Athens aimed at investigating people’s thermal sensation in a Mediterranean city. Based on 2313 questionnaires and microclimatic data the current work focuses on the relative frequencies of people’s evaluation of the therma...

  16. Unemployment in Greece: Econometric Evidence after the Athens 2004 Olympics and before the Global Financial Crisis of 2007–2009


    Stavros Rodokanakis


    This paper investigates the probability of employment in Greece and focuses on 2006, namely, well after the Athens 2004 Olympics and its fiscal stimulus and before the eruption of the global financial crisis of 2007–2009 that transformed into an economic and sovereign debt crisis with unprecedented consequences in the country's postwar economic history. Based on microdata from the Labour Force Survey, the analysis depicts the impact of gender, age, marital status, area of residence, level of ...

  17. On the limits of the air pollution predictability: the case of the surface ozone at Athens, Greece. (United States)

    Varotsos, Costas; Efstathiou, Maria; Tzanis, Chris; Deligiorgi, Despina


    The aim of this study is to investigate the potential effects of increased urbanization in the Athens city, Greece on the intrinsic features of the temporal fluctuations of the surface ozone concentration (SOC). The detrended fluctuation analysis was applied to the mean monthly values of SOC derived from ground-based observations collected at the centre of Athens basin during 1901-1940 and 1987-2007. Despite the present-day SOC doubling in respect to SOC historic levels, its fluctuations exhibit long-range power-law persistence, with similar features in both time periods. This contributes to an improved understanding of our predictive powers and enables better environmental management and more efficient decision-making processes. The extensive photochemistry enhancement observed in the Athens basin from the beginning of the twentieth century until the beginning of the twenty-first century seems not to have affected the long memory of SOC correlations. The strength of this memory stems from its temporal evolution and provides the limits of the air pollution predictability at various time scales.

  18. Monitoring the urban expansion of Athens using remote sensing and GIS techniques in the last 35 years (United States)

    Nikolakopoulos, Konstantinos; Pavlopoulos, Kosmas; Chalkias, Christos; Manou, Dora


    During the last thirty-five years the capital of Greece has suffered from an enormous internal immigration. Its population has overpassed the five millions and today almost the half population of Greece is squeezed in Athens metropolitan area. Because of the significant increase of population, the urban expansion in the basin of Athens was also excessive and in some cases catastrophic. Buildings have covered all the free places, new roads have been constructed, the drainage networks have been covered or disappeared and a lot of changes have been occurred to the landforms. The construction of the new airport (Elefterios Venizelos) at the beginning of this decade created a new commercial and urban pole at the eastern part of Athens and the constructive activity has been moved to new areas around the airport. Our aim was to detect and map all the changes that occurred in the urban area, estimate the urban expansion rate and the human interferences in the natural landscape, using GIS and remote sensing techniques. We have used satellite images from three different periods (1973, 1992, 2002) and topographic maps of 1:25.000 scale. The spatial resolution of all the satellite images ranges from 5 to 10 meters and is it acceptable for the monitoring and mapping of the urban growth. Supervised classification and on screen digitizing methods have been used in order to map the changes. Finally the qualitative and quantitative results of this study are presented in this paper.

  19. Hybrid plasmachemical reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lelevkin, V. M., E-mail:; Smirnova, Yu. G.; Tokarev, A. V. [Kyrgyz-Russian Slavic University (Kyrgyzstan)


    A hybrid plasmachemical reactor on the basis of a dielectric barrier discharge in a transformer is developed. The characteristics of the reactor as functions of the dielectric barrier discharge parameters are determined.

  20. Attrition reactor system (United States)

    Scott, Charles D.; Davison, Brian H.


    A reactor vessel for reacting a solid particulate with a liquid reactant has a centrifugal pump in circulatory flow communication with the reactor vessel for providing particulate attrition, resulting in additional fresh surface where the reaction can occur.

  1. Guidebook to nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Nero, A.V. Jr.


    A general introduction to reactor physics and theory is followed by descriptions of commercial nuclear reactor types. Future directions for nuclear power are also discussed. The technical level of the material is suitable for laymen.

  2. Motivation and volunteer participation in the «Athens 2004» Olympic Games

    Directory of Open Access Journals (Sweden)



    Full Text Available The present research tackles the topic of motives as they are developed by volunteers –who offer time-consuming services without expecting any material gains– and specifically the Olympic Volunteers of «Athens 2004». Four hundred-thirty (N = 430 volunteers completed the Scale of Motives, that was adapted in Greek from the functional approach of Omoto et al. (1993 and Chacon et al. (1998, aiming mainly at the testing of the hypothesis that the motives of volunteers who have previous volunteering experience, but also of those who wish (or continue to volunteer after the completion the Olympic Games, will differ from the motives of those volunteers who have not volunteered in the past or who do not aim at providing voluntary work in the future. The results supported the hypothesis, while the modified Greek scale offered high internal consistencies and strong indications of validity. The future review and reapplication of the design of the adapted questionnaire of Motives will likely eliminate any potential weaknesses and will allow the scale to reach full applicability.

  3. Possible Geomagnetic and Environmental Symptoms in the Area of Athens During the Solar Cycle No 22 (United States)

    Nastos, P. T.; Paliatsos, A. G.; Korbakis, G. K.; Tritakis, V. P.; Bergiannaki, A.; Psarros, K.; Paparrigopoulos, P.; Stafanis, K.

    The goal of this research is to confirm possible influences of environmental and geomagnetic variability in psychiatric hygiene of sensitive and heavily psychological patients. Three yearly samples of psychological patients consisted by four thousand cases (4000) each have been studied. The patients have been filed by the psychiatric clinic of the Eginition hospital in Athens where the three samples have been compiled during three very characteristic years of the No 22 11-year cycle, the maximum (1989), the minimum (1996) and one intermediate year of the descending branch (1994). A file with five to eight psychological symptoms like depression, sleep disturbance anxiety, aggressiveness etc. is attached to every patient. Each of these symptoms is correlated to the local geomagnetic index (k-index), the international geomagnetic index (Dst) and the environmental index (DI, Discomfort Index) in both daily and monthly basis. A clear seasonal variation in almost all symptoms and samples is present with maximum at the end of summer (August/September) and minimum at the end of winter (February-March). In addition very significant correlations among DI, Dst and some psychological symptoms appear. The main conclusion is that meteorological and geomagnetic factors play a significant role in the formation of sensitive psychological patients, behavior

  4. The 8 July 2002 storm over Athens: analysis of the Kifissos River/Canal overflows

    Directory of Open Access Journals (Sweden)

    K. Mazi


    Full Text Available We analyse the flood event of 8 July 2002 that caused overflows over portions of the lower reach of the Kifissos River/Canal. The storm covered only the lower basin area and was concentrated on the centre and the southwest side of Greater Athens. The issue that stirred the public opinion was whether the hydraulic works underway in lower Kifissos at that time were responsible for the overflows. We explore this issue with the hydrologic-hydraulic model of the Kifissos basin TELESIM. To shed light on the probable cause of the observed flooding, we ran TELESIM for two rain-field scenarios derived from the recorded point-rainfalls, computing flows for each scenario. Depth profiles for channel conditions without obstructions do not explain the observed flooding. With the channel taken as locally obstructed by flow-area reducing ramps plus bed-debris, estimated nominal overflows (bank-full level is threshold, but the water stays inside the channel compare well with actual ones for the milder rainfall scenario. Hence, the simulations support as plausible the hypothesis that flow obstructions due to the construction caused the overflows.

  5. Air pollution simulation and geographical information systems (GIS) applied to Athens International Airport. (United States)

    Theophanides, Mike; Anastassopoulou, Jane


    This study presents an improved methodology for analysing atmospheric pollution around airports using Gaussian-plume numerical simulation integrated with Geographical Information Systems (GIS). The new methodology focuses on streamlining the lengthy analysis process for Airport Environmental Impact Assessments by integrating the definition of emission sources, simulating and displaying the results in a GIS environment. One of the objectives of the research is to validate the methodology applied to the Athens International Airport, "Eleftherios Venizelos", to produce a realistic estimate of emission inventories, dispersion simulations and comparison to measured data. The methodology used a combination of the Emission Dispersion and Modelling System (EDMS) and the Atmospheric Dispersion and Modelling system (ADMS) to improve the analysis process. The second objective is to conduct numerical simulations under various adverse conditions (e.g. scenarios) and assess the dispersion in the surrounding areas. The study concludes that the use of GIS in environmental assessments provides a valuable advantage for organizing data and entering accurate geographical/topological information for the simulation engine. Emissions simulation produced estimates within 10% of published values. Dispersion simulations indicate that airport pollution will affect neighbouring cities such as Rafina and Loutsa. Presently, there are no measured controls in these areas. In some cases, airport pollution can contribute to as much as 40% of permissible EU levels in VOCs.

  6. Attitudes on euthanasia and physician-assisted suicide among medical students in Athens. (United States)

    Kontaxakis, Vp; Paplos, K G; Havaki-Kontaxaki, B J; Ferentinos, P; Kontaxaki, M-I V; Kollias, C T; Lykouras, E


    Attitudes towards assisted death activities among medical students, the future health gatekeepers, are scarce and controversial. The aims of this study were to explore attitudes on euthanasia and physician-assisted suicide among final year medical students in Athens, to investigate potential differences in attitudes between male and female medical students and to review worldwide attitudes of medical students regarding assisted death activities. A 20- item questionnaire was used. The total number of participants was 251 (mean age 24.7±1.8 years). 52.0% and 69.7% of the respondents were for the acceptance of euthanasia and physician-assisted suicide, respectively. Women's attitudes were more often influenced by religious convictions as well as by the fact that there is a risk that physician-assisted suicide might be misused with certain disadvantaged groups. On the other hand, men more often believed that a request for physician-assisted suicide from a terminally ill patient is prima-facie evidence of a mental disorder, usually depression. Concerning attitudes towards euthanasia among medical students in various countries there are contradictory results. In USA, the Netherlands, Hungary and Switzerland most of the students supported euthanasia and physician-assisted suicide. However, in many other countries such as Norway, Sweden, Yugoslavia, Italy, Germany, Sudan, Malaysia and Puerto Rico most students expressed negative positions regarding euthanasia and physician assisted suicide.

  7. Bioavailability and health risk assessment of potentially toxic elements in Thriasio Plain, near Athens, Greece. (United States)

    Antoniadis, Vasileios; Golia, Evangelia E; Shaheen, Sabry M; Rinklebe, Jörg


    Elevated concentrations of potentially toxic elements (PTEs) are usually found in areas of intense industrial activity. Thriasio Plain is a plain near Athens, Greece, where most of the heavy industry of the country has been situated for decades, but it also is a residential and horticultural area. We aimed at measuring the levels of PTEs in soils and indigenous plant species and assessing the health risk associated with direct soil ingestion. Samples of soils at roadsides and growing plants were collected from 31 sites of that area. Concentrations of Al, As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, V and Zn were measured in both soils (as pseudo-total) and aerial plant tissues. We found that As, Cd, Cr, Cu, Ni, Pb and Zn were higher than maximum regulatory limits. Element concentrations in plants were rather lower than expected, probably because indigenous plants have developed excluder behaviour over time. Copper and Zn soil-to-plant coefficients were highest among the other elements; for Cu this was unexpected, and probably associated with recent Cu-releasing industrial activity. Risk assessment analysis indicated that As was the element contributing more than 50 % of the health risk related to direct soil ingestion, followed by Cr, Pb, and, surprisingly, Mn. We concluded that in a multi-element contamination situation, elevated risk of PTEs (such as As, Cr and Pb) may reduce the tolerance limits of exposure to less-toxic elements (here, Mn).

  8. Development and application of Artificial Neural Networks in forecasting the maximum daily precipitation at Athens, Greece (United States)

    Nastos, P. T.; Paliatsos, A. G.; Larissi, I. K.; Moustris, K. P.


    Extreme daily precipitation events are involved in significant environmental damages, even in life loss, because of causing adverse impacts, such as flash floods, in urban and sometimes in rural areas. Thus, long-term forecast of such events is of great importance, in order to be prepared the local authorities to confront and mitigate the adverse consequences. The objective of this study is to estimate the possibility of forecasting the maximum daily precipitation for the next coming year. For this reason, appropriate prognostic models, such as Artificial Neural Networks (ANNs) were developed and applied. The data used for the analysis concern daily precipitation totals, which have been recorded at National Observatory of Athens (NOA), during the period 1891-2009. To evaluate the potential of daily extreme precipitation prognosis by the applied ANNs, a different period was considered than the one used for the ANNs training. Thus, the datasets of the period 1891-1980 were used as training datasets, while the datasets of the period 1981-2009 as validation datasets. Appropriate statistical indices, such as the Coefficient of Determination (R2), the Index of Agreement (IA), the Root Mean Square Error (RMSE), and the Mean Bias Error (MBE) were applied to test the reliability of the models. The findings of the analysis showed that, a quite satisfactory relationship at the statistically significant level of p<0.01 appears between the forecasted maximum daily precipitation totals for the next coming year and the respective observed ones.

  9. With or against nature? IVF, gender and reproductive agency in Athens, Greece. (United States)

    Paxson, Heather


    Based on ethnographic research in Athens, this paper argues that in vitro fertilization (IVF) in urban Greece does not so much make explicit the social construction of nature, as has been argued of the US and UK, but is accommodated into a prior understanding of "nature" as socially realized. Calling upon an ethic of maternal sacrifice, Athenian women see themselves taking charge of a natural process, often correcting damage done to them by nature. A sense that adults should produce children in order to realize their natures and be completed as women and men also poses particular, and gendered, ethical questions of fertility technologies: is this a proper way of realizing nature? While those who successfully use IVF depict assisted conception as "a natural" and "proper way of reproduction," some fear that others will view their child as abnormal. Contests over "normal" reproduction are articulated to a tradition/modernity dichotomy which Athenians discuss through an idiom of maturity. Believing that Greek society is not always mature enough to understand how natural IVF really is, couples turning to IVF follow one of the two strategies: to educate others or to completely hide it. Both groups want to guard against a view of IVF-in the terms of this volume-as a kind of "reproduction gone awry."

  10. Monitoring the effect of urban green areas on the heat island in Athens. (United States)

    Zoulia, I; Santamouris, M; Dimoudi, A


    The role of urban green areas in the microclimatic conditions of cities, during summer, is investigated in this paper through monitoring campaigns carried out at the National garden, at the city centre of Athens. Two types of investigations were carried out: i) a microscopic one that investigated the thermal conditions inside the Garden and the immediate surrounding urban area and ii) a macroscopic one that compared the temperature profile of the Garden with that of the greater city centre area. It was concluded that in microscopic level, the temperature profile inside the National Garden and the immediate surrounding urban area did not showed a clear evidence of the influence of the Garden and it was dependent on the characteristics of each location. In a macroscopic scale, the Garden was found cooler than the other monitored urban locations and temperature differences were mainly greater during the night, especially in streets with high building height to street width (H/W) ratio and low traffic, while in streets with high anthropogenic heat during the day, the biggest temperature differences were recorded during the day.

  11. Characterisation and management of ash produced in the hospital waste incinerator of Athens, Greece

    Energy Technology Data Exchange (ETDEWEB)

    Kougemitrou, Irene [Harokopio University of Athens, 70 El. Venizelou Str., 17671 Athens (Greece); Godelitsas, Athanasios, E-mail: [University of Athens, Panepistimioupoli Zographou, 15784 Athens (Greece); Tsabaris, Christos [Hellenic Center of Marine Research, 19013 Anavyssos (Greece); Stathopoulos, Vassilis [Technological Educational Institute of Chalkida, 34400 Psahna (Greece); Papandreou, Andreas [CERECO S.A. Ceramics and Refractories Technological Development Company, 34100 Chalkida (Greece); Gamaletsos, Platon [University of Athens, Panepistimioupoli Zographou, 15784 Athens (Greece); Economou, George [Institute of Geology and Mineral Exploration, Olympic Village, 13677 Acharnai (Greece); Papadopoulos, Dimitris [APOTEFROTIRAS S.A., Ano Liossia, 19200 Elefsina (Greece)


    Bottom and fly ash samples (BASH and FASH) from the APOTEFROTIRAS S.A. medical waste incinerator (Athens, Greece) were investigated. Powder-XRD data and geochemical diagrams showed BASH to be an amorphous material, analogous to basaltic glass, and FASH consisting of crystalline compounds (mainly CaClOH). Bulk analyses by ICP-MS and point analyses by SEM-EDS indicated a high content of heavy metals, such as Fe, Cu and Cr, in both samples. However, BASH was highly enriched in Ni while FASH was additionally enriched in Zn and Pb. Gamma-ray measurements showed that the radioactivity of both ash samples, due to natural and artificial radionuclides ({sup 137}Cs, {sup 57}Co), was within the permissible levels recommended by IAEA. According to EN-type leaching tests, BASH was practically inert with regard to the mobility of the hazardous elements in aqueous media. FASH, however, showed a relatively high EN (and TCLP) leachability with regard to Pb and Zn. Finally, the stabilisation method, suggested for the treatment of FASH, included compression of the powder into briquettes using an appropriate machine and embedding the briquettes into pozzolanic cement blocks. After this treatment, TCLP and EN-type tests showed minimal release of Pb and Zn, thereby demonstrating a reliable management of ash waste.

  12. On the corrosion and soiling effects on materials by air pollution in Athens, Greece

    Directory of Open Access Journals (Sweden)

    C. Tzanis


    Full Text Available In the frame of the European project, entitled MULTI-ASSESS, specimens of structural metals, glass, stone and concrete materials were exposed to air pollution at a station, which was installed for this purpose on a building, located in the centre of Athens. The main purpose of this project was to determine the corrosion and soiling effects of air pollution on materials. A set of the specimens was exposed in a position that was sheltered from rain and partly from wind, and another set was exposed in unsheltered positions on the roof of the above said building. In addition, other specimens were exposed at different heights on the same building, in order to investigate for the first time the corrosion and soiling effects on various materials as a function of height. For the determination of these effects, chemical analysis of the specimens was performed and basic parameters as the weight change, the layer thickness and the optical properties were calculated. Finally, the results obtained are discussed and their plausible interpretation is attempted.

  13. [Stress fractures in disabled athletes' preparation for the paralympic games in Athens, 2004: an assessment]. (United States)

    Laboute, E; Druvert, J C; Pailler, D; Piera, J-B


    To identify stress fracture frequency and the associated risk factors in disabled female athletes preparing the Paralympic Games in Athens in 2004. The study is focused on four athletes (including one with a vision impairment) among the 31 women selected to participate in the Paralympic Games. The medical records of selected athletes not having been able to participate in the Games due to a stress fracture were analyzed. One case of stress fracture to the first metatarsal was reported of one below-knee amputee and an additional case to the second metatarsal of one hemiplegic athlete. Two of three athletes with physical disability were unable to participate in the Games because of stress fracture occurring during the preparatory phase. Among four athletes selected to take part in the Paralympic Games. If morphological predispositions are inherent to the sportswomen, the main favouring factor to be retained is their running asymmetry. Training programmes must therefore take this characteristic into account and must not offer heavy-load repetitive exercise (such as endurance or jogging) at the expense of technique. Over-intense training exposes the disabled athlete to this type of pathology and is likely to affect his chances of competing.

  14. Validation of LIRIC aerosol concentration retrievals using airborne measurements during a biomass burning episode over Athens (United States)

    Kokkalis, Panagiotis; Amiridis, Vassilis; Allan, James D.; Papayannis, Alexandros; Solomos, Stavros; Binietoglou, Ioannis; Bougiatioti, Aikaterini; Tsekeri, Alexandra; Nenes, Athanasios; Rosenberg, Philip D.; Marenco, Franco; Marinou, Eleni; Vasilescu, Jeni; Nicolae, Doina; Coe, Hugh; Bacak, Asan; Chaikovsky, Anatoli


    In this paper we validate the Lidar-Radiometer Inversion Code (LIRIC) retrievals of the aerosol concentration in the fine mode, using the airborne aerosol chemical composition dataset obtained over the Greater Athens Area (GAA) in Greece, during the ACEMED campaign. The study focuses on the 2nd of September 2011, when a long-range transported smoke layer was observed in the free troposphere over Greece, in the height range from 2 to 3 km. CIMEL sun-photometric measurements revealed high AOD ( 0.4 at 532 nm) and Ångström exponent values ( 1.7 at 440/870 nm), in agreement with coincident ground-based lidar observations. Airborne chemical composition measurements performed over the GAA, revealed increased CO volume concentration ( 110 ppbv), with 57% sulphate dominance in the PM1 fraction. For this case, we compare LIRIC retrievals of the aerosol concentration in the fine mode with the airborne Aerosol Mass Spectrometer (AMS) and Passive Cavity Aerosol Spectrometer Probe (PCASP) measurements. Our analysis shows that the remote sensing retrievals are in a good agreement with the measured airborne in-situ data from 2 to 4 km. The discrepancies observed between LIRIC and airborne measurements at the lower troposphere (below 2 km), could be explained by the spatial and temporal variability of the aerosol load within the area where the airborne data were averaged along with the different time windows of the retrievals.


    Epler, E.P.; Hanauer, S.H.; Oakes, L.C.


    A control system is described for a nuclear reactor using enriched uranium fuel of the type of the swimming pool and other heterogeneous nuclear reactors. Circuits are included for automatically removing and inserting the control rods during the course of normal operation. Appropriate safety circuits close down the nuclear reactor in the event of emergency.

  16. Nuclear reactor overflow line (United States)

    Severson, Wayne J.


    The overflow line for the reactor vessel of a liquid-metal-cooled nuclear reactor includes means for establishing and maintaining a continuous bleed flow of coolant amounting to 5 to 10% of the total coolant flow through the overflow line to prevent thermal shock to the overflow line when the reactor is restarted following a trip. Preferably a tube is disposed concentrically just inside the overflow line extending from a point just inside the reactor vessel to an overflow tank and a suction line is provided opening into the body of liquid metal in the reactor vessel and into the annulus between the overflow line and the inner tube.

  17. Light water reactor safety

    CERN Document Server

    Pershagen, B


    This book describes the principles and practices of reactor safety as applied to the design, regulation and operation of light water reactors, combining a historical approach with an up-to-date account of the safety, technology and operating experience of both pressurized water reactors and boiling water reactors. The introductory chapters set out the basic facts upon which the safety of light water reactors depend. The central section is devoted to the methods and results of safety analysis. The accidents at Three Mile Island and Chernobyl are reviewed and their implications for light wate

  18. Nuclear reactor physics

    CERN Document Server

    Stacey, Weston M


    Nuclear reactor physics is the core discipline of nuclear engineering. Nuclear reactors now account for a significant portion of the electrical power generated worldwide, and new power reactors with improved fuel cycles are being developed. At the same time, the past few decades have seen an ever-increasing number of industrial, medical, military, and research applications for nuclear reactors. The second edition of this successful comprehensive textbook and reference on basic and advanced nuclear reactor physics has been completely updated, revised and enlarged to include the latest developme

  19. Spinning fluids reactor (United States)

    Miller, Jan D; Hupka, Jan; Aranowski, Robert


    A spinning fluids reactor, includes a reactor body (24) having a circular cross-section and a fluid contactor screen (26) within the reactor body (24). The fluid contactor screen (26) having a plurality of apertures and a circular cross-section concentric with the reactor body (24) for a length thus forming an inner volume (28) bound by the fluid contactor screen (26) and an outer volume (30) bound by the reactor body (24) and the fluid contactor screen (26). A primary inlet (20) can be operatively connected to the reactor body (24) and can be configured to produce flow-through first spinning flow of a first fluid within the inner volume (28). A secondary inlet (22) can similarly be operatively connected to the reactor body (24) and can be configured to produce a second flow of a second fluid within the outer volume (30) which is optionally spinning.

  20. Assessing insomnia in adolescents: comparison of Insomnia Severity Index, Athens Insomnia Scale and Sleep Quality Index. (United States)

    Chung, Ka-Fai; Kan, Katherine Ka-Ki; Yeung, Wing-Fai


    To compare the psychometric properties of the Chinese versions of Insomnia Severity Index (ISI), Athens Insomnia Scale (AIS) and Sleep Quality Index (SQI) for assessment and screening of insomnia in adolescents. This is a school-based survey of 1516 adolescents aged 12-19 years. Sleep-wake habit questionnaire, ISI, AIS, SQI, Epworth Sleepiness Scale (ESS) and 12-item General Health Questionnaire (GHQ-12) were administered. Insomnia Interview Schedule was used to assess the severity of insomnia symptoms and DSM-IV-TR diagnosis of insomnia. The Cronbach's alpha of ISI, AIS and SQI were 0.83, 0.81 and 0.65, respectively, and the 2-week test-retest reliability were 0.79, 0.80 and 0.72. All three scales had a 2-factor structure, and their scores were significantly correlated with sleep-wake variables, ESS and GHQ-12 scores, smoking and drinking habits, and academic performance. The areas under curve of ISI, AIS and SQI for detecting clinical insomnia were 0.85, 0.80 and 0.85, respectively. The optimal cut-offs for ISI, AIS and SQI were a total score of nine (sensitivity/specificity: 0.87/0.75), seven (sensitivity/specificity: 0.78/0.74) and five (sensitivity/specificity: 0.83/0.79), respectively. The Chinese versions of ISI, AIS and SQI are reliable and valid instruments. The ISI and AIS appear to have better psychometric properties than the SQI. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Assessment and prediction of short term hospital admissions: the case of Athens, Greece (United States)

    Kassomenos, P.; Papaloukas, C.; Petrakis, M.; Karakitsios, S.

    The contribution of air pollution on hospital admissions due to respiratory and heart diseases is a major issue in the health-environmental perspective. In the present study, an attempt was made to run down the relationships between air pollution levels and meteorological indexes, and corresponding hospital admissions in Athens, Greece. The available data referred to a period of eight years (1992-2000) including the daily number of hospital admissions due to respiratory and heart diseases, hourly mean concentrations of CO, NO 2, SO 2, O 3 and particulates in several monitoring stations, as well as, meteorological data (temperature, relative humidity, wind speed/direction). The relations among the above data were studied through widely used statistical techniques (multivariate stepwise analyses) and Artificial Neural Networks (ANNs). Both techniques revealed that elevated particulate concentrations are the dominant parameter related to hospital admissions (an increase of 10 μg m -3 leads to an increase of 10.2% in the number of admissions), followed by O 3 and the rest of the pollutants (CO, NO 2 and SO 2). Meteorological parameters also play a decisive role in the formation of air pollutant levels affecting public health. Consequently, increased/decreased daily hospital admissions are related to specific types of meteorological conditions that favor/do not favor the accumulation of pollutants in an urban complex. In general, the role of meteorological factors seems to be underestimated by stepwise analyses, while ANNs attribute to them a more important role. Comparison of the two models revealed that ANN adaptation in complicate environmental issues presents improved modeling results compared to a regression technique. Furthermore, the ANN technique provides a reliable model for the prediction of the daily hospital admissions based on air quality data and meteorological indices, undoubtedly useful for regulatory purposes.

  2. Artificial neural networks modeling for forecasting the maximum daily total precipitation at Athens, Greece (United States)

    Nastos, P. T.; Paliatsos, A. G.; Koukouletsos, K. V.; Larissi, I. K.; Moustris, K. P.


    Extreme daily precipitation events are involved in significant environmental damages, even in life loss, because of causing adverse impacts, such as flash floods, in urban and sometimes in rural areas. Thus, long-term forecast of such events is of great importance for the preparation of local authorities in order to confront and mitigate the adverse consequences. The objective of this study is to estimate the possibility of forecasting the maximum daily precipitation for the next coming year. For this reason, appropriate prognostic models, such as Artificial Neural Networks (ANNs) were developed and applied. The data used for the analysis concern annual maximum daily precipitation totals, which have been recorded at the National Observatory of Athens (NOA), during the long term period 1891-2009. To evaluate the potential of daily extreme precipitation forecast by the applied ANNs, a different period for validation was considered than the one used for the ANNs training. Thus, the datasets of the period 1891-1980 were used as training datasets, while the datasets of the period 1981-2009 as validation datasets. Appropriate statistical indices, such as the coefficient of determination (R2), the index of agreement (IA), the Root Mean Square Error (RMSE) and the Mean Bias Error (MBE), were applied to test the reliability of the models. The findings of the analysis showed that, a quite satisfactory relationship (R2 = 0.482, IA = 0.817, RMSE = 16.4 mm and MBE = + 5.2 mm) appears between the forecasted and the respective observed maximum daily precipitation totals one year ahead. The developed ANN seems to overestimate the maximum daily precipitation totals appeared in 1988 while underestimate the maximum in 1999, which could be attributed to the relatively low frequency of occurrence of these extreme events within GAA having impact on the optimum training of ANN.

  3. The new Athens center on data processing from the neutron monitor network in real time

    Directory of Open Access Journals (Sweden)



    Full Text Available The ground-based neutron monitors (NMs record galactic and solar relativistic cosmic rays which can play a useful key role in space weather forecasting, as a result of their interaction with interplanetary disturbances. The Earth's-based neutron monitor network has been used in order to produce a real-time prediction of space weather phenomena. Therefore, the Athens Neutron Monitor Data Processing Center (ANMODAP takes advantage of this unique multi-directional device to solve problems concerning the diagnosis and forecasting of space weather. At this moment there has been a multi-sided use of neutron monitors. On the one hand, a preliminary alert for ground level enhancements (GLEs may be provided due to relativistic solar particles and can be registered around 20 to 30 min before the arrival of the main part of lower energy particles responsible for radiation hazard. To make a more reliable prognosis of these events, real time data from channels of lower energy particles and X-ray intensity from the GOES satellite are involved in the analysis. The other possibility is to search in real time for predictors of geomagnetic storms when they occur simultaneously with Forbush effects, using hourly, on-line accessible neutron monitor data from the worldwide network and applying a special method of processing. This chance of prognosis is only being elaborated and considered here as one of the possible uses of the Neutron Monitor Network for forecasting the arrival of interplanetary disturbance to the Earth. The achievements, the processes and the future results, are discussed in this work.

  4. The new Athens center on data processing from the neutron monitor network in real time

    Directory of Open Access Journals (Sweden)



    Full Text Available The ground-based neutron monitors (NMs record galactic and solar relativistic cosmic rays which can play a useful key role in space weather forecasting, as a result of their interaction with interplanetary disturbances. The Earth's-based neutron monitor network has been used in order to produce a real-time prediction of space weather phenomena. Therefore, the Athens Neutron Monitor Data Processing Center (ANMODAP takes advantage of this unique multi-directional device to solve problems concerning the diagnosis and forecasting of space weather. At this moment there has been a multi-sided use of neutron monitors. On the one hand, a preliminary alert for ground level enhancements (GLEs may be provided due to relativistic solar particles and can be registered around 20 to 30 min before the arrival of the main part of lower energy particles responsible for radiation hazard. To make a more reliable prognosis of these events, real time data from channels of lower energy particles and X-ray intensity from the GOES satellite are involved in the analysis. The other possibility is to search in real time for predictors of geomagnetic storms when they occur simultaneously with Forbush effects, using hourly, on-line accessible neutron monitor data from the worldwide network and applying a special method of processing. This chance of prognosis is only being elaborated and considered here as one of the possible uses of the Neutron Monitor Network for forecasting the arrival of interplanetary disturbance to the Earth. The achievements, the processes and the future results, are discussed in this work.

  5. FORMS OF DEMOCRACY IN EDUCATION: Open Access and Distance Education–Athens, Greece

    Directory of Open Access Journals (Sweden)

    Reviewed by Antonis LIONARAKIS


    Full Text Available The 4th International Conference in Open and Distance Learning - Forms of Democracy in Education: Open Access and Distance Education (ICODL 2007 had a special role to play this time: it was focused on the relationship between distance education and democratic principles which are connected and interrelated to eachother. These principles identify a new social role of distance education. Educational applications can be more flexible and effective when they follow some basic From the early beginning open universities and alternative forms of education have defined e democratic framework for educational systems. Their connection with the conventional educational system has influenced to a great extend new innovations in the system. With this approach we can realize that distance learning may become a bridge between these innovations and the initial ideals of democracy and human ICODL 2007 took place in Athens, Greece, from 23 to 25 of November 2007. There were 160 papers presented from 36 countries: Greece, Cyprus, Belgium, Spain, Iran,Canada, Turkey, South Africa, Italy, Palestine, France, Ireland, Japan, Nigeria,Bulgaria, USA, Austria, Finland, Pakistan, Great Britain, Ukraine, Egypt, Lithuania, Israel, India, Czech Republic, Brazil, Portugal, Botswana, Barbados–West Indies,The key–note speakers of ICODL 2007 were Professor Alan Tait, Pro-Vice-Chancellor, The Open University/UK, with the title ―What are Open Universities for?‖, Professor Michael Grahame Moore, the Pennsylvania State University and Editor of the American Journal of Distance Education with the title ―The scholarship of distance education: a review of the 40 years of growth and achievement‖ and Professor Paul Clark, Senior Research Fellow in the IET at the UK Open University with the title

  6. Indoor air quality assessment in the air traffic control tower of the Athens Airport, Greece. (United States)

    Helmis, Costas G; Assimakopoulos, Vasiliki D; Flocas, Helena A; Stathopoulou, Ourania I; Sgouros, George; Hatzaki, Maria


    In this study, an assessment of indoor air quality (IAQ) and thermal comfort in the Athens Traffic Control Tower (ATCT) offices of Hellinicon building complex, which is mechanically ventilated, is presented. Measurements of PM(10), PM(2.5), TVOCs and CO(2) concentrations were performed during three experimental cycles, while the Thom Discomfort Index was calculated to describe the employees' feeling of discomfort. The aim of the first cycle was to identify the IAQ status, the second to investigate the effectiveness of certain measures taken, and the third to continuously monitor and control IAQ. During the first two cycles, daily spot measurements of TVOCs and CO(2) were performed at various indoor locations and at the respective outdoor air intake positions, in addition with mean 24-h spot measurements of indoor PM(10) and PM(2.5). Results revealed that pollution levels vary according to the occupancy and the kind of activity. Following that, an automated system (IMAS) was designed and employed to continuously monitor indoor and outdoor CO(2), TVOCs, temperature and relative humidity. The ultimate scope was to control the IAQ and offer acceptable comfort conditions to the employees, whose work is of special nature and extremely demanding. Intervention scenarios were formulated and applied to the system to improve indoor conditions, when and where necessary. Regarding the third cycle, 1-year measurements collected from the system to examine its effectiveness. While it was shown that discomfort may be attributed to co-existence of unsatisfactory thermal comfort conditions and IAQ, usually the sole predominant factor of discomfort feeling is thermal comfort.

  7. Neutron fluxes in test reactors

    Energy Technology Data Exchange (ETDEWEB)

    Youinou, Gilles Jean-Michel [Idaho National Lab. (INL), Idaho Falls, ID (United States)


    Communicate the fact that high-power water-cooled test reactors such as the Advanced Test Reactor (ATR), the High Flux Isotope Reactor (HFIR) or the Jules Horowitz Reactor (JHR) cannot provide fast flux levels as high as sodium-cooled fast test reactors. The memo first presents some basics physics considerations about neutron fluxes in test reactors and then uses ATR, HFIR and JHR as an illustration of the performance of modern high-power water-cooled test reactors.

  8. An objective definition of air mass types affecting Athens, Greece; the corresponding atmospheric pressure patterns and air pollution levels. (United States)

    Sindosi, O A; Katsoulis, B D; Bartzokas, A


    This work aims at defining characteristic air mass types that dominate in the region of Athens, Greece during the cold (November-March) and the warm (May-September) period of the year and also at evaluating the corresponding concentration levels of the main air pollutants. For each air mass type, the mean atmospheric pressure distribution (composite maps) over Europe and the Mediterranean is estimated in order to reveal the association of atmospheric circulation with air pollution levels in Athens. The data basis for this work consists of daily values of thirteen meteorological and six pollutant parameters covering the period 1993-97. The definition of the characteristic air mass types is attempted objectively by using the methods of Factor Analysis and Cluster Analysis. The results show that during the cold period of the year there are six prevailing air mass types (at least 3% of the total number of days) and six infrequent ones. The examination of the corresponding air pollution concentration levels shows that the primary air pollutants appear with increased concentrations when light or southerly winds prevail. This is usually the case when a high pressure system is located over the central Mediterranean or a low pressure system lays over south Italy, respectively. Low levels of the primary pollutants are recorded under northeasterly winds, mainly caused by a high pressure system over Ukraine. During the warm period of the year, the southwestern Asia thermal low and the subtropical anticyclone of the Atlantic Ocean affect Greece. Though these synoptic systems cause almost stagnant conditions, four main air mass types are dominant and ten others, associated with extreme weather, are infrequent. Despite the large amounts of total solar radiation characterizing this period, ozone concentrations remain at low levels in central Athens because of its destruction by nitric oxide.

  9. Urban soil geochemistry in Athens, Greece: The importance of local geology in controlling the distribution of potentially harmful trace elements. (United States)

    Argyraki, Ariadne; Kelepertzis, Efstratios


    Understanding urban soil geochemistry is a challenging task because of the complicated layering of the urban landscape and the profound impact of large cities on the chemical dispersion of harmful trace elements. A systematic geochemical soil survey was performed across Greater Athens and Piraeus, Greece. Surface soil samples (0-10cm) were collected from 238 sampling sites on a regular 1×1km grid and were digested by a HNO3-HCl-HClO4-HF mixture. A combination of multivariate statistics and Geographical Information System approaches was applied for discriminating natural from anthropogenic sources using 4 major elements, 9 trace metals, and 2 metalloids. Based on these analyses the lack of heavy industry in Athens was demonstrated by the influence of geology on the local soil chemistry with this accounting for 49% of the variability in the major elements, as well as Cr, Ni, Co, and possibly As (median values of 102, 141, 16 and 24mg kg(-1) respectively). The contribution to soil chemistry of classical urban contaminants including Pb, Cu, Zn, Sn, Sb, and Cd (medians of 45, 39, 98, 3.6, 1.7 and 0.3mg kg(-1) respectively) was also observed; significant correlations were identified between concentrations and urbanization indicators, including vehicular traffic, urban land use, population density, and timing of urbanization. Analysis of soil heterogeneity and spatial variability of soil composition in the Greater Athens and Piraeus area provided a representation of the extent of anthropogenic modifications on natural element loadings. The concentrations of Ni, Cr, and As were relatively high compared to those in other cities around the world, and further investigation should characterize and evaluate their geochemical reactivity. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Validation of CALIPSO space-borne-derived attenuated backscatter coefficient profiles using a ground-based lidar in Athens, Greece

    Directory of Open Access Journals (Sweden)

    R. E. Mamouri


    Full Text Available We present initial aerosol validation results of the space-borne lidar CALIOP -onboard the CALIPSO satellite- Level 1 attenuated backscatter coefficient profiles, using coincident observations performed with a ground-based lidar in Athens, Greece (37.9° N, 23.6° E. A multi-wavelength ground-based backscatter/Raman lidar system is operating since 2000 at the National Technical University of Athens (NTUA in the framework of the European Aerosol Research LIdar NETwork (EARLINET, the first lidar network for tropospheric aerosol studies on a continental scale. Since July 2006, a total of 40 coincidental aerosol ground-based lidar measurements were performed over Athens during CALIPSO overpasses. The ground-based measurements were performed each time CALIPSO overpasses the station location within a maximum distance of 100 km. The duration of the ground–based lidar measurements was approximately two hours, centred on the satellite overpass time. From the analysis of the ground-based/satellite correlative lidar measurements, a mean bias of the order of 22% for daytime measurements and of 8% for nighttime measurements with respect to the CALIPSO profiles was found for altitudes between 3 and 10 km. The mean bias becomes much larger for altitudes lower that 3 km (of the order of 60% which is attributed to the increase of aerosol horizontal inhomogeneity within the Planetary Boundary Layer, resulting to the observation of possibly different air masses by the two instruments. In cases of aerosol layers underlying Cirrus clouds, comparison results for aerosol tropospheric profiles become worse. This is attributed to the significant multiple scattering effects in Cirrus clouds experienced by CALIPSO which result in an attenuation which is less than that measured by the ground-based lidar.

  11. Development of an integrated methodology for the energy needs of a major urban city: The case study of Athens, Greece

    DEFF Research Database (Denmark)

    Xydis, George


    In the present paper a Linear Programming (LP) methodology for the city of Athens, Attica region is implemented trying to identify the energy supply levels based on the energy use, aiming to determine the optimal way for the energy needs to be covered. The final aim was to find the best solution....../s to meet the (metropolitan) city's energy needs using Renewable Energy Sources (RES) and additionally implement a techno-economic analysis through a developed tool, in order to find which RES should participate in the city's energy system examining different scenarios focusing not only on the projects......' economical success but also on minimizing the cost for the society....


    Treshow, M.


    Reactors of the boiling water type are described wherein water serves both as the moderator and coolant. The reactor system consists essentially of a horizontal pressure vessel divided into two compartments by a weir, a thermal neutronic reactor core having vertical coolant passages and designed to use water as a moderator-coolant posltioned in one compartment, means for removing live steam from the other compartment and means for conveying feed-water and water from the steam compartment to the reactor compartment. The system further includes auxiliary apparatus to utilize the steam for driving a turbine and returning the condensate to the feed-water inlet of the reactor. The entire system is designed so that the reactor is self-regulating and has self-limiting power and self-limiting pressure features.

  13. Fast Spectrum Reactors

    CERN Document Server

    Todd, Donald; Tsvetkov, Pavel


    Fast Spectrum Reactors presents a detailed overview of world-wide technology contributing to the development of fast spectrum reactors. With a unique focus on the capabilities of fast spectrum reactors to address nuclear waste transmutation issues, in addition to the well-known capabilities of breeding new fuel, this volume describes how fast spectrum reactors contribute to the wide application of nuclear power systems to serve the global nuclear renaissance while minimizing nuclear proliferation concerns. Readers will find an introduction to the sustainable development of nuclear energy and the role of fast reactors, in addition to an economic analysis of nuclear reactors. A section devoted to neutronics offers the current trends in nuclear design, such as performance parameters and the optimization of advanced power systems. The latest findings on fuel management, partitioning and transmutation include the physics, efficiency and strategies of transmutation, homogeneous and heterogeneous recycling, in addit...


    Spinrad, B.I.


    A novel thermal reactor was designed in which a first reflector formed from a high atomic weight, nonmoderating material is disposed immediately adjacent to the reactor core. A second reflector composed of a moderating material is disposed outwardly of the first reflector. The advantage of this novel reflector arrangement is that the first reflector provides a high slow neutron flux in the second reflector, where irradiation experiments may be conducted with a small effect on reactor reactivity.

  15. Remote Reactor Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, Adam [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dazeley, Steve [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dobie, Doug [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Marleau, Peter [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brennan, Jim [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gerling, Mark [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sumner, Matthew [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sweany, Melinda [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    The overall goal of the WATCHMAN project is to experimentally demonstrate the potential of water Cerenkov antineutrino detectors as a tool for remote monitoring of nuclear reactors. In particular, the project seeks to field a large prototype gadolinium-doped, water-based antineutrino detector to demonstrate sensitivity to a power reactor at ~10 kilometer standoff using a kiloton scale detector. The technology under development, when fully realized at large scale, could provide remote near-real-time information about reactor existence and operational status for small operating nuclear reactors out to distances of many hundreds of kilometers.

  16. Development of reactor graphite (United States)

    Haag, G.; Mindermann, D.; Wilhelmi, G.; Persicke, H.; Ulsamer, W.


    The German graphite development programme for High Temperature Reactors has been based on the assumption that reactor graphite for core components with lifetime fluences of up to 4 × 10 22 neutrons per cm 2 (EDN) at 400°C can be manufactured from regular pitch coke. The use of secondary coke and vibrational moulding techniques have allowed production of materials with very small anisotropy, high strength, and high purity which are the most important properties of reactor graphite. A variety of graphite grades has been tested in fast neutron irradiation experiments. The results show that suitable graphites for modern High Temperature Reactors with spherical fuel elements are available.

  17. Oscillatory flow chemical reactors

    National Research Council Canada - National Science Library

    Slavnić Danijela S; Bugarski Branko M; Nikačević Nikola M


    .... However, the reactions of interests for the mentioned industry sectors are often slow, thus continuous tubular reactors would be impractically long for flow regimes which provide sufficient heat...

  18. Membrane reactors at Degussa. (United States)

    Wöltinger, Jens; Karau, Andreas; Leuchtenberger, Wolfgang; Drauz, Karlheinz


    The review covers the development of membrane reactor technologies at Degussa for the synthesis of fine chemicals. The operation of fed-batch or continuous biocatalytic processes in the enzyme membrane reactor (EMR) is well established at Degussa. Degussa has experience of running EMRs from laboratory gram scale up to a production scale of several hundreds of tons per year. The transfer of the enzyme membrane reactor from biocatalysis to chemical catalysis in the chemzyme membrane reactor (CMR) is discussed. Various homogeneous catalysts have been investigated in the CMR, and the scope and limitation of this new technique is discussed.

  19. Pressurizing new reactors

    Energy Technology Data Exchange (ETDEWEB)

    Neill, J.S.


    The Technical Division was asked recently to consider designs for new reactors that would add 8000 MW capacity to the Savannah River Plant. One modification of the existing SRP design that would enable a higher power rating, and therefore require fewer new reactors, is an increase in the maximum pressure in the D{sub 2}O system. The existing reactors at SRP are designed for a maximum pressure in the gas plenum of only 5 psig. Higher pressures enable higher D{sub 2} temperatures and higher sheath temperatures without local boiling or burnout. The requirements in reactor cooling facilities at any given power level would therefore be reduced by pressurizing.


    King, L.D.P.


    A homogeneous nuclear power reactor utilizing forced circulation of the liquid fuel is described. The reactor does not require fuel handling outside of the reactor vessel during any normal operation including complete shutdown to room temperature, the reactor being selfregulating under extreme operating conditions and controlled by the thermal expansion of the liquid fuel. The liquid fuel utilized is a uranium, phosphoric acid, and water solution which requires no gus exhaust system or independent gas recombining system, thereby eliminating the handling of radioiytic gas.

  1. PM{sub 10} composition during an intense Saharan dust transport event over Athens (Greece)

    Energy Technology Data Exchange (ETDEWEB)

    Remoundaki, E., E-mail: [National Technical University of Athens (NTUA), School of Mining and Metallurgical Engineering, Laboratory of Environmental Science and Engineering, Heroon Polytechniou 9, 15780 Zografou (Greece); Bourliva, A. [Aristotle University of Thessaloniki (AUTH), Department of Geology, 54124 Thessaloniki (Greece); Hellenic Open University, School of Science and Technology, 26335 Patras (Greece); Kokkalis, P.; Mamouri, R.E.; Papayannis, A. [National Technical University of Athens (NTUA), Laser Remote Sensing Laboratory, Heroon Polytechniou 9, 15780 Zografou (Greece); Grigoratos, T.; Samara, C. [Aristotle University of Thessaloniki (AUTH), Department of Chemistry, Environmental Pollution Control Laboratory, 54124 Thessaloniki (Greece); Tsezos, M. [National Technical University of Athens (NTUA), School of Mining and Metallurgical Engineering, Laboratory of Environmental Science and Engineering, Heroon Polytechniou 9, 15780 Zografou (Greece)


    The influence of Saharan dust on the air quality of Southern European big cities became a priority during the last decade. The present study reports results on PM{sub 10} monitored at an urban site at 14 m above ground level during an intense Saharan dust transport event. The elemental composition was determined by Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF) for 12 elements: Si, Al, Fe, K, Ca, Mg, Ti, S, Ni, Cu, Zn and Mn. PM{sub 10} concentrations exceeded the EU limit (50 {mu}g/m{sup 3}) several times during the sampling period. Simultaneous maxima have been observed for the elements of crustal origin. The concentrations of all the elements presented a common maximum, corresponding to the date where the atmosphere was heavily charged with particulate matter permanently for an interval of about 10 h. Sulfur and heavy metal concentrations were also associated to local emissions. Mineral dust represented the largest fraction of PM{sub 10} reaching 79%. Seven days back trajectories have shown that the air masses arriving over Athens, originated from Western Sahara. Scanning Electron Microscopy coupled with Energy Dispersive X-ray analysis (SEM-EDX) revealed that particle agglomerates were abundant, most of them having sizes < 2 {mu}m. Aluminosilicates were predominant in dust particles also rich in calcium which was distributed between calcite, dolomite, gypsum and Ca-Si particles. These results were consistent with the origin of the dust particles and the elemental composition results. Sulfur and heavy metals were associated to very fine particles < 1 {mu}m. - Highlights: {yields} The paper focuses on the contribution of Saharan dust in PM10 levels at an urban site. {yields} High Ca and Fe, calcite, illite and smectites and poor quartz contents are related to source-regions. {yields} The data sets presented are in very good agreement and are also strongly confirmed by literature. {yields} Dust contribution in PM10 can be of comparable importance for

  2. Volatility of source apportioned wintertime organic aerosol in the city of Athens (United States)

    Louvaris, Evangelos E.; Florou, Kalliopi; Karnezi, Eleni; Papanastasiou, Dimitrios K.; Gkatzelis, Georgios I.; Pandis, Spyros N.


    The volatility distribution of ambient organic aerosol (OA) and its components was measured during the winter of 2013 in the city of Athens combining a thermodenuder (TD) and a High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS). Positive Matrix Factorization (PMF) analysis of both the ambient and the thermodenuder AMS-spectra resulted in a four-factor solution for the OA, namely: hydrocarbon-like OA (HOA), biomass burning OA (BBOA), cooking OA (COA), and oxygenated OA (OOA). The thermograms of the four factors were analyzed and the corresponding volatility distributions were estimated using the volatility basis set (VBS). All four factors included compounds with a wide range of effective volatilities from 10 to less than 10-4 μg m-3 at 298 K. Almost 40% of the HOA consisted of low-volatility organic compounds (LVOCs) with the semi-volatile compounds (SVOCs) representing roughly 30%, while the remaining 30% consisted of extremely low volatility organic compounds (ELVOCs). BBOA was more volatile than the HOA factor on average, with 10% ELVOCs, 40% LVOCs, and 50% SVOCs. 10% of the COA consisted of ELVOCs, another 65% LVOCs, and 50% SVOCs. Finally, the OOA was the least volatile factor and included 40% ELVOCs, 25% LVOCs, and 35% SVOCs. Combining the volatility distributions and the O:C ratios of the various factors, we placed our results in the 2D-VBS analysis framework of Donahue et al. (2012). HOA and BBOA are in the expected region but also include an ELVOC component. COA is in similar range as HOA, but on average is half an order of magnitude more volatile. The OOA in these wintertime conditions had a moderate O:C ratio and included both semi-volatile and extremely low volatility components. The above results are sensitive to the assumed values of the effective vaporization enthalpy and the accommodation coefficient. A reduction of the accommodation coefficient by an order of magnitude or the reduction of the vaporization enthalpy by 20 kJ mol-1

  3. Development of a 3D Information System for the Old City Centre of Athens

    Directory of Open Access Journals (Sweden)

    Nikos Kaskampas


    Full Text Available The representation of three dimensional city models has been gaining ground increasingly in many scientific fields in the recent years. 3D City Modelling is a scale representation of natural and artificial objects in order to present the spatial data and highlight the social development of the city. Depending on its importance or the purpose of use, an object can be represented in various levels of detail. An increasing tendency to 3D city models is their integration into GIS, which proves to be an effective tool for managing, analyzing and planning in order to make decisions about technical, administrative and financial matters. A combination of digital photogrammetric techniques and laser scanning data contribute greatly to this, since a variety of data, such as aerial, satellite and terrestrial images, point clouds from airborne and terrestrial laser systems, and also a variety of photogrammetric and mobile mapping methods are available. The objective of this paper is the development of a 3D Information System (IS for the three-dimensional geometric documentation of the buildings owned by the Ministry of Culture in the old city centre of Athens, Greece, named “Plaka”. The area has been inhabited continuously since the prehistoric era, it has a special architectural style and includes a number of unique cultural heritage monuments. The data used for the reconstruction of the 3D model of Plaka consisted of aerial and terrestrial images, while raster, vector and descriptive data were used for the creation of a 2D GIS, which served as the background for the development of the 3D GIS. The latter includes all of the qualitative and quantitative information related to the 3D building models owned by the Ministry of Culture according to users’ needs. Each building in the vicinity of Plaka was depicted in one of the four different levels of detail created for the purpose of the study, according to their ownership status and other criteria. The

  4. Brominated flame retardants and organochlorine pollutants in eggs of little owls (Athene noctua) from Belgium

    Energy Technology Data Exchange (ETDEWEB)

    Jaspers, Veerle [Department of Biology, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk (Belgium); Covaci, Adrian [Toxicological Centre, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk (Belgium)]. E-mail:; Maervoet, Johan [Toxicological Centre, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk (Belgium); Dauwe, Tom [Department of Biology, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk (Belgium); Voorspoels, Stefan [Toxicological Centre, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk (Belgium); Schepens, Paul [Toxicological Centre, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk (Belgium); Eens, Marcel [Department of Biology, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk (Belgium)


    Residues of brominated diphenylethers (PBDEs), organochlorinated pesticides (OCPs) and polychlorinated biphenyls (PCBs) were measured in 40 eggs of little owls (Athene noctua), a terrestrial top predator from Belgium. The major organohalogens detected were PCBs (median 2,600 ng/g lipid, range 790-23000 ng/g lipid). PCB 153,138/163, 170, 180 and 187 were the predominant congeners and constituted 71% of total sum PCBs. PBDEs were measurable in all samples, but their concentrations were much lower than for PCBs, with a range from 29-572 ng/g lipid (median 108 ng/g lipid). The most prevalent PBDE congeners in little owl egg samples were BDE 47, 99 and 153. This profile differs from the profile in marine bird species, for which BDE 47 was the dominant congener, indicating that terrestrial birds may be more exposed to higher brominated BDE congeners than marine birds. The fully brominated BDE 209 could be detected in one egg sample (17 ng/g lipid), suggesting that higher brominated BDEs may accumulate in terrestrial food chains. Brominated biphenyl (BB) 153 was determined in all egg samples, with levels ranging from 0.6 to 5.6 ng/g lipid (median 1.3 ng/g lipid). Additionally, hexabromocyclododecane (HBCD) could be identified and quantified in only two eggs at levels of 20 and 50 ng/g lipid. OCPs were present at low concentrations, suggesting a rather low contamination of the sampled environment with OCPs (median concentrations of sum DDTs: 826 ng/g lipid, sum chlordanes: 1,016 ng/g lipid, sum HCHs: 273 ng/g lipid). Hexachlorobenzene (HCB) and octachlorostyrene (OCS) were also found at low median levels of 134 and 3.4 ng/g lipid, respectively. Concentrations of most analytes were significantly higher in eggs collected from deserted nests in comparison to addled (unhatched) eggs, while eggshell thickness did not differ between deserted and addled eggs. No significant correlations were found between eggshell thickness and the analysed organohalogens. - PBDEs are measurable

  5. Averroës in The school of Athens: a Renaissance man and his contribution to Western thought and neuroscience. (United States)

    Belen, Deniz; Bolay, Hayrunnisa


    The European Renaissance was a revolutionary movement in human history. In this era of the rebirth of humanity, a great number of valuable artworks were created. One of these masterpieces is the magnificent wall painting The School of Athens, by Raphael, which is also known as a "visualization of knowledge." Raphael depicted almost all ancient Greek philosophers in this fresco. The painting displays one noticeable figure among the scholars: the philosopher/scientist Averroës from Andalusia. Western thought was greatly influenced by Averroës' philosophy. Averroës was as extraordinary a physician as he was a philosopher. His medical works presented novel concepts such as the discovery of the photoreceptor function of the retina, describing symptoms and signs of Parkinson's disease, and proposing a cardiac/vascular origin of cerebral stroke. In this article, we aimed to introduce Averroës' works and his contribution to neuroscience in the context of art, framed particularly with Raphael's masterwork The School of Athens.

  6. The Economic Crisis in Greece and Its Impact on the Seasonality of Suicides in the Athens Greater Area. (United States)

    Christodoulou, Christos; Efstathiou, Vasiliki; Michopoulos, Ioannis; Gkerekou, Maria; Paraschakis, Antonios; Koutsaftis, Filippos; Douzenis, Athanassios


    The economic crisis and the implementation of austerity measures in Greece lead to significant socioeconomic changes. The effects of the crisis were mainly felt by the Greek population during the years 2011 and 2012. This study aimed to investigate the impact of Greece's economic crisis on the seasonality of suicides in the Athens Greater Area. Data were collected for all recorded cases of suicides committed over a 5-year period (from 2008 to 2012) from the Athens Department of Forensic Medicine. Two sub-periods were studied in relation to the economic crisis: 2008-2010 and 2011-2012. Seasonality was estimated with the Poison regression variant of the circular normal distribution. Suicide seasonality appeared significant during 2008-2010 (relative risk, RR=1.36) and strengthened in the years 2011-2012 (RR=1.69), when the impact of the austerity measures was increasingly being felt by the Greek society. Regarding the latter sub-period, seasonality was established for males (RR=1.75), individuals aged 45 years or more (RR=1.75) and suicide by hanging (RR=1.96). The economic crisis in Greece, especially in the period during its effects had a significant impact on the population's economic condition, seems to have strengthened the seasonality of suicides, while a noteworthy suicide risk of 96% was revealed for suicides by hanging (peak in early June).

  7. Technical specifications, Hanford production reactors

    Energy Technology Data Exchange (ETDEWEB)

    Gilbert, W.D. [comp.


    These technical specifications are applicable to the eight operating production reactor facilities, B, C, D, DR, F, H, KE, and KW. Covered are operating and performance restrictions and administrative procedures. Areas covered by the operating and performance restrictions are reactivity, reactor control and safety elements, power level, temperature and heat flux, reactor fuel loadings, reactor coolant systems, reactor confinement, test facilities, code compliance, and reactor scram set points. Administrative procedures include process control procedures, training programs, audits and inspections, and reports and records.

  8. Reactor Materials Research

    Energy Technology Data Exchange (ETDEWEB)

    Van Walle, E


    The activities of the Reactor Materials Research Department of the Belgian Nuclear Research Centre SCK-CEN in 2000 are summarised. The programmes within the department are focussed on studies concerning (1) fusion, in particular mechanical testing; (2) Irradiation Assisted Stress Corrosion Cracking (IASCC); (3) nuclear fuel; and (4) Reactor Pressure Vessel Steel (RPVS)

  9. Space Nuclear Reactor Engineering

    Energy Technology Data Exchange (ETDEWEB)

    Poston, David Irvin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    We needed to find a space reactor concept that could be attractive to NASA for flight and proven with a rapid turnaround, low-cost nuclear test. Heat-pipe-cooled reactors coupled to Stirling engines long identified as the easiest path to near-term, low-cost concept.


    Fraas, A.P.


    A reflector for nuclear reactors that comprises an assembly of closely packed graphite rods disposed with their major axes substantially perpendicular to the interface between the reactor core and the reflector is described. Each graphite rod is round in transverse cross section at (at least) its interface end and is provided, at that end, with a coaxial, inwardly tapering hole. (AEC)

  11. Mirror reactor surface study

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, A. L.; Damm, C. C.; Futch, A. H.; Hiskes, J. R.; Meisenheimer, R. G.; Moir, R. W.; Simonen, T. C.; Stallard, B. W.; Taylor, C. E.


    A general survey is presented of surface-related phenomena associated with the following mirror reactor elements: plasma first wall, ion sources, neutral beams, director converters, vacuum systems, and plasma diagnostics. A discussion of surface phenomena in possible abnormal reactor operation is included. Several studies which appear to merit immediate attention and which are essential to the development of mirror reactors are abstracted from the list of recommended areas for surface work. The appendix contains a discussion of the fundamentals of particle/surface interactions. The interactions surveyed are backscattering, thermal desorption, sputtering, diffusion, particle ranges in solids, and surface spectroscopic methods. A bibliography lists references in a number of categories pertinent to mirror reactors. Several complete published and unpublished reports on surface aspects of current mirror plasma experiments and reactor developments are also included.

  12. Nuclear reactor design

    CERN Document Server


    This book focuses on core design and methods for design and analysis. It is based on advances made in nuclear power utilization and computational methods over the past 40 years, covering core design of boiling water reactors and pressurized water reactors, as well as fast reactors and high-temperature gas-cooled reactors. The objectives of this book are to help graduate and advanced undergraduate students to understand core design and analysis, and to serve as a background reference for engineers actively working in light water reactors. Methodologies for core design and analysis, together with physical descriptions, are emphasized. The book also covers coupled thermal hydraulic core calculations, plant dynamics, and safety analysis, allowing readers to understand core design in relation to plant control and safety.

  13. Status of French reactors

    Energy Technology Data Exchange (ETDEWEB)

    Ballagny, A. [Commissariat a l`Energie Atomique, Saclay (France)


    The status of French reactors is reviewed. The ORPHEE and RHF reactors can not be operated with a LEU fuel which would be limited to 4.8 g U/cm{sup 3}. The OSIRIS reactor has already been converted to LEU. It will use U{sub 3}Si{sub 2} as soon as its present stock of UO{sub 2} fuel is used up, at the end of 1994. The decision to close down the SILOE reactor in the near future is not propitious for the start of a conversion process. The REX 2000 reactor, which is expected to be commissioned in 2005, will use LEU (except if the fast neutrons core option is selected). Concerning the end of the HEU fuel cycle, the best option is reprocessing followed by conversion of the reprocessed uranium to LEU.

  14. Growth, livability, feed consumption, and carcass composition of the Athens Canadian Random Bred 1955 meat-type chicken versus the 2012 high-yielding Cobb 500 broiler

    National Research Council Canada - National Science Library

    Collins, K E; Kiepper, B H; Ritz, C W; McLendon, B L; Wilson, J L


    A flock of the Athens Canadian Random Bred (ACRB), a 1955 meat-type chicken control strain, was raised alongside a flock of 2012 Cobb 500 fast feathering high-yielding broilers to determine selection changes over the past 57 yr...

  15. The relationship between aerosol backscatter coefficient and atmospheric relative humidity in an urban area over Athens, Greece, using Raman lidar and radiosonde data

    DEFF Research Database (Denmark)

    Angelou, Nikolas; Papayannis, A.; Mamouri, R.E.


    of the Planetary Boundary Layer (PBL); PBL up to PBL + 2000 m; and PBL + 2000 m up to 6000 m. The properties and seasonal variations of the height of the PBL were also studied. The annual mean PBL height over Athens was found to be (1320 ± 480) m, while during the warm period of the year (spring–summer) the PBL...

  16. Contaminant exposure in relation to spatio-temporal variation in diet composition: A case study of the little owl (Athene noctua)

    NARCIS (Netherlands)

    Schipper, A.M.; Wijnhoven, S.; Baveco, H.; Van den Brink, N.W.


    We assessed dietary exposure of the little owl Athene noctua to trace metal contamination in a Dutch Rhine River floodplain area. Diet composition was calculated per month for three habitat types, based on the population densities of six prey types (earthworms, ground beetles and four small mammal

  17. Nuclear reactor control column (United States)

    Bachovchin, Dennis M.


    The nuclear reactor control column comprises a column disposed within the nuclear reactor core having a variable cross-section hollow channel and containing balls whose vertical location is determined by the flow of the reactor coolant through the column. The control column is divided into three basic sections wherein each of the sections has a different cross-sectional area. The uppermost section of the control column has the greatest cross-sectional area, the intermediate section of the control column has the smallest cross-sectional area, and the lowermost section of the control column has the intermediate cross-sectional area. In this manner, the area of the uppermost section can be established such that when the reactor coolant is flowing under normal conditions therethrough, the absorber balls will be lifted and suspended in a fluidized bed manner in the upper section. However, when the reactor coolant flow falls below a predetermined value, the absorber balls will fall through the intermediate section and into the lowermost section, thereby reducing the reactivity of the reactor core and shutting down the reactor.

  18. Reactor Safety Research Programs

    Energy Technology Data Exchange (ETDEWEB)

    Edler, S. K.


    This document summarizes the work performed by Pacific Northwest Laboratory (PNL) from January 1 through March 31, 1981, for the Division of Reactor Safety Research within the U.S. Nuclear Regulatory Commission (NRC). Evaluations of nondestructive examination (NDE) techniques and instrumentation are reported; areas of investigation include demonstrating the feasibility of determining the strength of structural graphite, evaluating the feasibility of detecting and analyzing flaw growth in reactor pressure boundary systems, examining NDE reliability and probabilistic fracture mechanics, and assessing the integrity of pressurized water reactor (PWR) steam generator tubes where service-induced degradation has been indicated. Experimental data and analytical models are being provided to aid in decision-making regarding pipeto- pipe impacts following postulated breaks in high-energy fluid system piping. Core thermal models are being developed to provide better digital codes to compute the behavior of full-scale reactor systems under postulated accident conditions. Fuel assemblies and analytical support are being provided for experimental programs at other facilities. These programs include loss-ofcoolant accident (LOCA) simulation tests at the NRU reactor, Chalk River, Canada; fuel rod deformation, severe fuel damage, and postaccident coolability tests for the ESSOR reactor Super Sara Test Program, Ispra, Italy; the instrumented fuel assembly irradiation program at Halden, Norway; and experimental programs at the Power Burst Facility, Idaho National Engineering Laboratory (INEL). These programs will provide data for computer modeling of reactor system and fuel performance during various abnormal operating conditions.

  19. Reactor power monitoring device

    Energy Technology Data Exchange (ETDEWEB)

    Oda, Naotaka; Igawa, Shinji; Kitazono, Hideaki


    The present invention provides a reactor power monitoring device capable of ensuring circumstance resistance, high reliability and high speed transmission even if an APRM is disposed in a reactor building (R/B). Namely, signal processing sections (APRM) for transmitting data to a central control chamber are distributed in the reactor building at an area at the lowest temperature among areas where the temperature control in an emergency state is regulated, and a transmission processing section (APRM-I/F) for transmitting data to the other systems is disposed to the central control chamber. An LPRM signal transmission processing section is constituted such that LPRM signals can be transmitted at a high speed by DMA. Set values relevant to reactor tripping (neutron flux high, thermal output high and sudden reduction of a reactor core flow rate) are stored in the APRM-I/F, and reactor tripping calculation is conducted in the APRM-I/F. With such procedure, a reactor power monitoring device having enhanced control function can be attained. (N.H.)

  20. Athens: New capital of traditional Greek music: Testimonies on musical life at the beginning of the twentieth century

    Directory of Open Access Journals (Sweden)

    Peno Vesna


    Full Text Available During its long Byzantine and Post-Byzantine history Constantinople was the center for church art in general, but especially for music. This old city on the Bosporus maintained its prime position until the beginning of the 20th century when, because of new political and social conditions, the Greek people started to acquire their independence and freedom, and Athens became the new capital in the cultural as well as the political sense. During the first decades of the 20th century the Athenian music scene was marked by an intensive dispute between those musicians who leaned towards the European musical heritage and its methods in musical pedagogy, and those who called themselves traditionalists and were engaged in the preservation of traditional values of church and folk music. The best insight into the circumstances in which Greek musical life was getting a new direction are offered by the numerous musical journals published in Athens before the First World War. Among them, The Formigs is of the special interest, firstly because of the long period during which it was published (1901-1912, and secondly because of its main orientation. The editor Ioannes Tsoklis, a church chanter, and his main collaborator, the famous Constantinopolitan musician and theorist and later Principal of the Department for Byzantine music at Athens musical school Konstantinos Psahos, with other associates firmly represented the traditional position. That is why most of the published articles and the orientation of the journal generally were dedicated to the controversial problems and current musical events that were attracting public attention. The editorial board believed that there was a connection between the preservation of musical traditions and their development on one side, and foreign musical influences that were evident in the promotion of polyphonic church music, which had been totally foreign to the Greek Orthodox church until the end of the 19th century, on

  1. Nuclear reactor reflector (United States)

    Hopkins, R.J.; Land, J.T.; Misvel, M.C.


    A nuclear reactor reflector is disclosed that comprises a stack of reflector blocks with vertical water flow passages to cool the reflector. The interface between blocks is opposite support points for reactor fuel rods. Water flows between the reflector and the reactor barrel from passages in a bottom block. The top block contains a flange to limit this flow and the flange has a slot to receive an alignment pin that is welded to the barrel. The pin is held in the slot by two removable shims. Alignment bars extend the length of the stack in slots machined in each block when the stack is assembled. 12 figs.

  2. Fast Breeder Reactor studies

    Energy Technology Data Exchange (ETDEWEB)

    Till, C.E.; Chang, Y.I.; Kittel, J.H.; Fauske, H.K.; Lineberry, M.J.; Stevenson, M.G.; Amundson, P.I.; Dance, K.D.


    This report is a compilation of Fast Breeder Reactor (FBR) resource documents prepared to provide the technical basis for the US contribution to the International Nuclear Fuel Cycle Evaluation. The eight separate parts deal with the alternative fast breeder reactor fuel cycles in terms of energy demand, resource base, technical potential and current status, safety, proliferation resistance, deployment, and nuclear safeguards. An Annex compares the cost of decommissioning light-water and fast breeder reactors. Separate abstracts are included for each of the parts.

  3. Reactor flux calculations

    Energy Technology Data Exchange (ETDEWEB)

    Lhuillier, D. [Commissariat à l' Énergie Atomique et aux Énergies Alternatives, Centre de Saclay, IRFU/SPhN, 91191 Gif-sur-Yvette (France)


    The status of the prediction of reactor anti-neutrino spectra is presented. The most accurate method is still the conversion of total β spectra of fissionning isotopes as measured at research reactors. Recent re-evaluations of the conversion process led to an increased predicted flux by few percent and were at the origin of the so-called reactor anomaly. The up to date predictions are presented with their main sources of error. Perspectives are given on the complementary ab-initio predictions and upcoming experimental cross-checks of the predicted spectrum shape.


    Metcalf, H.E.


    Methods of controlling reactors are presented. Specifically, a plurality of neutron absorber members are adjustably disposed in the reactor core at different distances from the center thereof. The absorber members extend into the core from opposite faces thereof and are operated by motive means coupled in a manner to simultaneously withdraw at least one of the absorber members while inserting one of the other absorber members. This feature effects fine control of the neutron reproduction ratio by varying the total volume of the reactor effective in developing the neutronic reaction.

  5. Nuclear reactor reflector (United States)

    Hopkins, Ronald J.; Land, John T.; Misvel, Michael C.


    A nuclear reactor reflector is disclosed that comprises a stack of reflector blocks with vertical water flow passages to cool the reflector. The interface between blocks is opposite support points for reactor fuel rods. Water flows between the reflector and the reactor barrel from passages in a bottom block. The top block contains a flange to limit this flow and the flange has a slot to receive an alignment pin that is welded to the barrel. The pin is held in the slot by two removable shims. Alignment bars extend the length of the stack in slots machined in each block when the stack is assembled.

  6. Microfluidic electrochemical reactors (United States)

    Nuzzo, Ralph G [Champaign, IL; Mitrovski, Svetlana M [Urbana, IL


    A microfluidic electrochemical reactor includes an electrode and one or more microfluidic channels on the electrode, where the microfluidic channels are covered with a membrane containing a gas permeable polymer. The distance between the electrode and the membrane is less than 500 micrometers. The microfluidic electrochemical reactor can provide for increased reaction rates in electrochemical reactions using a gaseous reactant, as compared to conventional electrochemical cells. Microfluidic electrochemical reactors can be incorporated into devices for applications such as fuel cells, electrochemical analysis, microfluidic actuation, pH gradient formation.

  7. New reactor type proposed

    CERN Multimedia


    "Russian scientists at the Research Institute of Nuclear Power Engineering in Moscow are hoping to develop a new reactor that will use lead and bismuth as fuel instead of uranium and plutonium" (1/2 page).

  8. The thrill of victory and the agony of defeat: spontaneous expressions of medal winners of the 2004 Athens Olympic Games. (United States)

    Matsumoto, David; Willingham, Bob


    Facial behaviors of medal winners of the judo competition at the 2004 Athens Olympic Games were coded with P. Ekman and W. V. Friesen's (1978) Facial Affect Coding System (FACS) and interpreted using their Emotion FACS dictionary. Winners' spontaneous expressions were captured immediately when they completed medal matches, when they received their medal from a dignitary, and when they posed on the podium. The 84 athletes who contributed expressions came from 35 countries. The findings strongly supported the notion that expressions occur in relation to emotionally evocative contexts in people of all cultures, that these expressions correspond to the facial expressions of emotion considered to be universal, that expressions provide information that can reliably differentiate the antecedent situations that produced them, and that expressions that occur without inhibition are different than those that occur in social and interactive settings. ((c) 2006 APA, all rights reserved).

  9. Predictors of cadmium and lead concentrations in the blood of residents from the metropolitan area of Athens (Greece)

    Energy Technology Data Exchange (ETDEWEB)

    Sakellari, Aikaterini, E-mail: [National and Kapodistrian University of Athens, Division III, Laboratory of Environmental Chemistry, Zografou, Panepistimiopolis, 157 84 Athens (Greece); Karavoltsos, Sotirios [National and Kapodistrian University of Athens, Division III, Laboratory of Environmental Chemistry, Zografou, Panepistimiopolis, 157 84 Athens (Greece); Kalogeropoulos, Nick [Harokopio University, Department of Nutrition Science and Dietetics, Laboratory of Chemistry-Biochemistry-Physical Chemistry of Foods, 176 71 Athens (Greece); Theodorou, Dimitrios [School of Chemical Engineering, Laboratory of Fuels and Lubricants Technology, National Technical University of Athens, Iroon Polytechneiou 9, Athens 15780 (Greece); Dedoussis, George [Harokopio University, Department of Nutrition Science and Dietetics, Laboratory of Molecular Biology, 176 71 Athens (Greece); Chrysohoou, Christina [First Cardiology Clinic, Hippokration Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens (Greece); Dassenakis, Manos; Scoullos, Michael [National and Kapodistrian University of Athens, Division III, Laboratory of Environmental Chemistry, Zografou, Panepistimiopolis, 157 84 Athens (Greece)


    The Cd and Pb blood contents of healthy adult subjects who are non-occupationally exposed and living in the metropolitan area of Athens (Greece) have not been assessed thus far. Additionally, Greeks rank first among EU27 in terms of smoking habits. To fill the existing gap, we aimed to evaluate the predictors and propose reference values (RVs) of the Cd (CdB) and Pb (PbB) blood concentrations in residents of the metropolitan area of Athens (Greece). Age, sex, smoking, alcohol drinking, educational status and nutritional habits were used as variables, with an emphasis on smoking. CdB and PbB determinations were performed directly by graphite furnace atomic absorption spectrometry (GFAAS) following the appropriate dilution of the samples with Triton-X-100. The RVs of CdB and PbB proposed for the general adult population of the Metropolitan area of Athens, Greece (upper limit of the 95% CI of the 95th percentile of the distribution of values), were 2.3 and 88 μg L{sup −} {sup 1} (P95: 1.8 and 77 μg L{sup −} {sup 1}; 95% CI (P95): 1.5–2.3 and 70–88 μg L{sup −} {sup 1}), respectively. Males had a higher median CdB (0.69 μg L{sup −} {sup 1}) than females (0.55 μg L{sup −} {sup 1}). Subjects aged < 40 years had a lower median CdB (0.51 μg L{sup −} {sup 1}) than the elderly (≥ 60 years; 0.60 μg L{sup −} {sup 1}). The CdB in smokers (1.2 μg L{sup −} {sup 1}) was almost threefold higher than in non-smokers (0.46 μg L{sup −} {sup 1}). The PbB levels were higher in males (31 μg L{sup −} {sup 1}) than females (20 μg L{sup −} {sup 1}). Subjects aged < 40 years had a lower median PbB (17 μg L{sup −} {sup 1}) than the elderly (≥ 60 years; 32 μg L{sup −} {sup 1}). A multiple linear regression analysis demonstrated that the predictor variables for the CdB levels were the standardized beta weight, smoking, age, alcohol consumption, and intake of leafy vegetables, whereas for the PbB levels they were sex and age. - Highlights: • Data on

  10. Implementation of the New Approach for the Dose-Response Functions Development for the Case of Athens and Greece (United States)

    Christodoulakis, J.; Tzanis, C. G.; Varotsos, C. A.; Kouremadas, G.


    Dose-response functions (DRFs) are functions used for estimating corrosion and/or soiling levels of materials used in constructions and cultural monuments. In order to achieve this, DRFs lean on ground-based measurements of specific air pollution and climatic parameters like nitrogen oxides, ozone, temperature and others. In DRAGON 3 2015 Symposium we presented a new approach which proposed a technique for using satellite-based data for the necessary parameters instead of ground-based expanding in this way: a) the usage of DRFs in cases/areas where there is no availability of in situ measurements, b) the applicability of satellite-based data. In this work we present mapping results of deterioration levels (corrosion and soiling) for the case of Athens, Greece but also for the whole Greece country.

  11. Estimation of the Linke and Unsworth-Monteith turbidity factors in the visible spectrum: application for Athens, Greece

    Energy Technology Data Exchange (ETDEWEB)

    Kambezidis, H.D.; Katevatis, E.M.; Petrakis, M.; Lykoudis, S. [National Observatory of Athens (Greece). Institute of Meteorology and Physics of the Atmospheric Environment; Asimakopoulos, D.N. [National Observatory of Athens (Greece). Institute of Meteorology and Physics of the Atmospheric Environment; National and Capodestrian University of Athens (Greece). Dept. of Physics


    Expressions for the Linke, T{sub Lvis}, and Unsworth-Monteith, T{sub Uvis}, turbidity parameters in the visible region of the solar spectrum are derived. They are based on new determinations of the visible transmittances for the various atmospheric constituents obtained by spectrally integrating the wavelength-dependent atmospheric transmittances. Application of the T{sub Lvis} and T{sub Uvis} expressions for Athens is made for the first time; this is done from measurements of direct solar irradiance in the period 1992-1995. A linear interdependence between T{sub Lvis} and T{sub Uvis} is derived, as in the case of their broadband counterparts. The seasonal, monthly and daily variations of these turbidity parameters are also investigated. (author)

  12. Department of Reactor Technology

    DEFF Research Database (Denmark)

    Risø National Laboratory, Roskilde

    The general development of the Department of Reactor Technology at Risø during 1981 is presented, and the activities within the major subject fields are described in some detail. Lists of staff, publications, and computer programs are included.......The general development of the Department of Reactor Technology at Risø during 1981 is presented, and the activities within the major subject fields are described in some detail. Lists of staff, publications, and computer programs are included....

  13. Environmental ground borne noise and vibration protection of sensitive cultural receptors along the Athens Metro Extension to Piraeus. (United States)

    Vogiatzis, Konstantinos


    Attiko Metro S.A., the state company ensuring the development of the Athens Metro network, has recently initiated a new extension of 7.6 km, has planned for line 3 of Athens Metro from Haidari to Piraeus "Dimotikon Theatre" towards "University of Piraeus" (forestation), connecting the major Piraeus Port with "Eleftherios Venizelos" International Airport. The Piraeus extension consists of a Tunnel Boring Machine, 2 tracks and, tunnel sections, as well as 6 stations and a forestation (New Austrian Tunnelling Method) at the end of the alignment. In order to avoid the degradation of the urban acoustic environment from ground borne noise and vibration during metro operation, the assessment of the required track types and possible noise mitigation measures was executed, and for each section and each sensitive building, the ground borne noise and vibration levels will be numerically predicted. The calculated levels were then compared with ground borne noise and vibration level criteria. The necessary mitigation measures were defined in order to guarantee, in each location along the extension, the allowable ground borne Noise and Vibration max. levels inside nearby sensitive buildings taking into account alternative Transfer Functions for ground borne noise diffusion inside the buildings. Ground borne noise levels were proven to be higher than the criterion where special track work is present and also in the case of the sensitive receptor: "Dimotikon Theatre". In order to reduce the ground borne noise levels to allowable values in these sections, the installation of tracks and special track work on a floating slab was assessed and recommended. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Sources of atmospheric aerosol from long-term measurements (5 years) of chemical composition in Athens, Greece. (United States)

    Paraskevopoulou, D; Liakakou, E; Gerasopoulos, E; Mihalopoulos, N


    To identify the sources of aerosols in Greater Athens Area (GAA), a total of 1510 daily samples of fine (PM 2.5) and coarse (PM 10-2,5) aerosols were collected at a suburban site (Penteli), during a five year period (May 2008-April 2013) corresponding to the period before and during the financial crisis. In addition, aerosol sampling was also conducted in parallel at an urban site (Thissio), during specific, short-term campaigns during all seasons. In all these samples mass and chemical composition measurements were performed, the latest only at the fine fraction. Particulate organic matter (POM) and ionic masses (IM) are the main contributors of aerosol mass, equally contributing by accounting for about 24% of the fine aerosol mass. In the IM, nss-SO4(-2) is the prevailing specie followed by NO3(-) and NH4(+) and shows a decreasing trend during the 2008-2013 period similar to that observed for PM masses. The contribution of water in fine aerosol is equally significant (21 ± 2%), while during dust transport, the contribution of dust increases from 7 ± 2% to 31 ± 9%. Source apportionment (PCA and PMF) and mass closure exercises identified the presence of six sources of fine aerosols: secondary photochemistry, primary combustion, soil, biomass burning, sea salt and traffic. Finally, from winter 2012 to winter 2013 the contribution of POM to the urban aerosol mass is increased by almost 30%, reflecting the impact of wood combustion (dominant fuel for domestic heating) to air quality in Athens, which massively started in winter 2013. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Natural convection reactor

    Energy Technology Data Exchange (ETDEWEB)

    Babcock, D.F.; Bernath, L.; Menegus, R.L.; Ring, H.F.


    A previous report described the conceptual design of a plutonium producing reactor that may be characterized as follows: Power output (2000 MW); cooling - (natural convection of light water through the reactor, up through a draft tube to an evaporative cooling pond, then back to the reactor, and fuel (400 to 500 tons of uranium enriched to 1.2% U-235). Because this reactor would be cooled by the natural convection of light water, it is believed that the construction costs would be significantly less than for a Savannah or Hanford type reactor. Such expensive items as water treatment and water pumping facilities would be eliminated entirely. The inventory of 500 tons of slightly enriched uranium, however, is an unattractive feature. It represents not only a large dollar investment but also makes the reactor less attractive for construction during periods of national emergency because of the almost certain scarcity of even slightly enriched uranium at that time. The Atomic Energy Commission asked that the design be reviewed with the objective of reducing the inventory of uranium, The results of this review are given in this report.

  16. Reactor Safety Planning for Prometheus Project, for Naval Reactors Information

    Energy Technology Data Exchange (ETDEWEB)

    P. Delmolino


    The purpose of this letter is to submit to Naval Reactors the initial plan for the Prometheus project Reactor Safety work. The Prometheus project is currently developing plans for cold physics experiments and reactor prototype tests. These tests and facilities may require safety analysis and siting support. In addition to the ground facilities, the flight reactor units will require unique analyses to evaluate the risk to the public from normal operations and credible accident conditions. This letter outlines major safety documents that will be submitted with estimated deliverable dates. Included in this planning is the reactor servicing documentation and shipping analysis that will be submitted to Naval Reactors.

  17. Scaleable, High Efficiency Microchannel Sabatier Reactor Project (United States)

    National Aeronautics and Space Administration — A Microchannel Sabatier Reactor System (MSRS) consisting of cross connected arrays of isothermal or graded temperature reactors is proposed. The reactor array...

  18. Rune Frederiksen, Elizabeth R. Gebhard & Alexander Sokolicek (eds.), The Architecture of the Ancient Greek Theatre, Monographs of the Danish Institute, Volume 17 (Aarhus: Aarhus University Press and The Danish Institute at Athens, 2015)


    Miller, William C.


    A review of the book: Rune Frederiksen, Elizabeth R. Gebhard & Alexander Sokolicek (eds.), The Architecture of the Ancient Greek Theatre, Monographs of the Danish Institute, Volume 17 (Aarhus: Aarhus University Press and The Danish Institute at Athens, 2015)


    Mumm, J.F.; North, D.C. Jr.; Rock, H.R.; Geston, D.K.


    A nuclear reactor is described for use in a merchant marine ship. The reactor is of pressurized light water cooled and moderated design in which three passes of the water through the core in successive regions of low, intermediate, and high heat generation and downflow in a fuel region are made. The foregoing design makes a compact reactor construction with extended core life. The core has an egg-crate lattice containing the fuel elements confined between a lower flow baffle and upper grid plate, with the latter serving also as part of a turn- around manifold from which the entire coolant is distributed into the outer fuel elements for the second pass through the core. The inner fuel elements are cooled in the third pass.

  20. Nuclear Rocket Engine Reactor

    CERN Document Server

    Lanin, Anatoly


    The development of a nuclear rocket engine reactor (NRER ) is presented in this book. The working capacity of an active zone NRER under mechanical and thermal load, intensive neutron fluxes, high energy generation (up to 30 MBT/l) in a working medium (hydrogen) at temperatures up to 3100 K is displayed. Design principles and bearing capacity of reactors area discussed on the basis of simulation experiments and test data of a prototype reactor. Property data of dense constructional, porous thermal insulating and fuel materials like carbide and uranium carbide compounds in the temperatures interval 300 - 3000 K are presented. Technological aspects of strength and thermal strength resistance of materials are considered. The design procedure of possible emergency processes in the NRER is developed and risks for their origination are evaluated. Prospects of the NRER development for pilotless space devices and piloted interplanetary ships are viewed.

  1. Nuclear reactor safety device (United States)

    Hutter, Ernest


    A safety device is disclosed for use in a nuclear reactor for axially repositioning a control rod with respect to the reactor core in the event of an upward thermal excursion. Such safety device comprises a laminated helical ribbon configured as a tube-like helical coil having contiguous helical turns with slidably abutting edges. The helical coil is disclosed as a portion of a drive member connected axially to the control rod. The laminated ribbon is formed of outer and inner laminae. The material of the outer lamina has a greater thermal coefficient of expansion than the material of the inner lamina. In the event of an upward thermal excursion, the laminated helical coil curls inwardly to a smaller diameter. Such inward curling causes the total length of the helical coil to increase by a substantial increment, so that the control rod is axially repositioned by a corresponding amount to reduce the power output of the reactor.

  2. Heat dissipating nuclear reactor (United States)

    Hunsbedt, A.; Lazarus, J.D.


    Disclosed is a nuclear reactor containment adapted to retain and cool core debris in the unlikely event of a core meltdown and subsequent breach in the reactor vessel. The reactor vessel is seated in a cavity which has a thick metal sidewall that is integral with a thick metal basemat at the bottom of the cavity. The basemat extends beyond the perimeter of the cavity sidewall. Underneath the basemat is a porous bed with water pipes and steam pipes running into it. Water is introduced into the bed and converted into steam which is vented to the atmosphere. A plurality of metal pilings in the form of H-beams extend from the metal base plate downwardly and outwardly into the earth.

  3. Reactor for exothermic reactions (United States)

    Smith, Jr., Lawrence A.; Hearn, Dennis; Jones, Jr., Edward M.


    A liquid phase process for oligomerization of C.sub.4 and C.sub.5 isoolefins or the etherification thereof with C.sub.1 to C.sub.6 alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of to F. Wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled.

  4. An Overview of Reactor Concepts, a Survey of Reactor Designs. (United States)


    implies, this reactor uses gas as the primary coolant . The coolant has a higher exit temperature when leaving the core than the PWR water 6 AFWL-TN-84...nuclear reactors, coolants must be used to ensure material components are not subject to failure due to the temperature exceeding melting points...Reactors that use deu- terium (heavy water) as a coolant can use natural uranium as a fuel. The * Canadian reactor, CANDU , utilizes this concept

  5. Oscillatory flow chemical reactors

    Directory of Open Access Journals (Sweden)

    Slavnić Danijela S.


    Full Text Available Global market competition, increase in energy and other production costs, demands for high quality products and reduction of waste are forcing pharmaceutical, fine chemicals and biochemical industries, to search for radical solutions. One of the most effective ways to improve the overall production (cost reduction and better control of reactions is a transition from batch to continuous processes. However, the reactions of interests for the mentioned industry sectors are often slow, thus continuous tubular reactors would be impractically long for flow regimes which provide sufficient heat and mass transfer and narrow residence time distribution. The oscillatory flow reactors (OFR are newer type of tube reactors which can offer solution by providing continuous operation with approximately plug flow pattern, low shear stress rates and enhanced mass and heat transfer. These benefits are the result of very good mixing in OFR achieved by vortex generation. OFR consists of cylindrical tube containing equally spaced orifice baffles. Fluid oscillations are superimposed on a net (laminar flow. Eddies are generated when oscillating fluid collides with baffles and passes through orifices. Generation and propagation of vortices create uniform mixing in each reactor cavity (between baffles, providing an overall flow pattern which is close to plug flow. Oscillations can be created by direct action of a piston or a diaphragm on fluid (or alternatively on baffles. This article provides an overview of oscillatory flow reactor technology, its operating principles and basic design and scale - up characteristics. Further, the article reviews the key research findings in heat and mass transfer, shear stress, residence time distribution in OFR, presenting their advantages over the conventional reactors. Finally, relevant process intensification examples from pharmaceutical, polymer and biofuels industries are presented.

  6. Reactor Materials Research

    Energy Technology Data Exchange (ETDEWEB)

    Van Walle, E


    The activities of SCK-CEN's Reactor Materials Research Department for 2001 are summarised. The objectives of the department are: (1) to evaluate the integrity and behaviour of structural materials used in nuclear power industry; (2) to conduct research to unravel and understand the parameters that determine the material behaviour under or after irradiation; (3) to contribute to the interpretation, the modelling of the material behaviour and to develop and assess strategies for optimum life management of nuclear power plant components. The programmes within the department are focussed on studies concerning (1) Irradiation Assisted Stress Corrosion Cracking (IASCC); (2) nuclear fuel; and (3) Reactor Pressure Vessel Steel.

  7. Nuclear reactor apparatus (United States)

    Wade, Elman E.


    A lifting, rotating and sealing apparatus for nuclear reactors utilizing rotating plugs above the nuclear reactor core. This apparatus permits rotation of the plugs to provide under the plug refueling of a nuclear core. It also provides a means by which positive top core holddown can be utilized. Both of these operations are accomplished by means of the apparatus lifting the top core holddown structure off the nuclear core while stationary, and maintaining this structure in its elevated position during plug rotation. During both of these operations, the interface between the rotating member and its supporting member is sealingly maintained.

  8. Perspectives on reactor safety

    Energy Technology Data Exchange (ETDEWEB)

    Haskin, F.E. [New Mexico Univ., Albuquerque, NM (United States). Dept. of Chemical and Nuclear Engineering; Camp, A.L. [Sandia National Labs., Albuquerque, NM (United States)


    The US Nuclear Regulatory Commission (NRC) maintains a technical training center at Chattanooga, Tennessee to provide appropriate training to both new and experienced NRC employees. This document describes a one-week course in reactor, safety concepts. The course consists of five modules: (1) historical perspective; (2) accident sequences; (3) accident progression in the reactor vessel; (4) containment characteristics and design bases; and (5) source terms and offsite consequences. The course text is accompanied by slides and videos during the actual presentation of the course.

  9. Safe reactor power

    Energy Technology Data Exchange (ETDEWEB)

    Menegus, R.L.; Ring, H.F.; Bernath, L.


    The upper limit on reactor operating power is established not only by safety considerations during steady-state operation but also by the requirement that during an accident no permanent damage be inflicted upon the reactor or the fuel charge. Two general categories of accidents are recognized; they are the ``nuclear runaway`` and the ``loss of coolant flow`` incidents. In this memorandum an incident of the latter type is analyzed. It is assumed that the safety rods function normally, and a method is defined for establishing the highest operating power that may be permitted if the postulated accident is to do no damage.

  10. Non Methane Hydrocarbons (NMHCs) at the centre of Athens: variability and relative contribution of traffic and wood burning (United States)

    Panopoulou, Anastasia; Liakakou, Eleni; Psiloglou, Basil; Gros, Valerie; Bonsang, Bernard; Sauvage, Stephane; Locoge, Nadine; Lianou, Maria; Gerasopoulos, Evangelos; Mihalopoulos, Nikolaos


    Non-methane hydrocarbons (NMHC) can be found in significant concentrations in urban areas. They are emitted by biogenic and anthropogenic sources like vehicle exhaust, gasoline evaporation and solvent use. Once emitted they mainly react with hydroxyl radicals (OH) and in the presence of nitrogen oxides (NOx) lead to the formation of secondary pollutants such as ozone (O3), peroxy acetyl nitrate (PAN) and secondary organic aerosols. In Great Athens Area (GAA) despite the numerous air quality issues especially with exceedances in ozone and particulate matter (PM), continuous monitoring of NMHCs is absent. This work presents the first results of a ChArMEX/TRANSEMED project dealing with VOC source apportionment and emission inventory evaluation in megacities around the Mediterranean basin. A representative site in the centre of Athens is progressively equipped with high performance instruments in order to measure continuously NMHCs (time resolution of 30 min) over a long period. The main objective of this presentation is the determination of the ambient level and temporal variability of C2-C6 NMHCs, as well as the impact of the sources controlling their variability. The importance of this work is attributed to the high time resolution measurements providing a detailed light hydrocarbons profile of the area for first time in the GAA. An automatic gas chromatograph (airmoVOC C2-C6 Chromatrap GC, Chromatotec, France) equipped with a flame ionization detector (FID) has been used for the in-situ measurements of NMHCS with two to six carbon atoms (C2-C6 NMHCs) during the period from the 16 of October to end of December 2015. In addition, meteorological and auxiliary data for major gases (CO, O3, NOx) and particulates (PM and Black Carbon (BC) are also available. Atmospheric concentrations of NMHCs range from below the detection limit to a few ppbs, for example almost 14 ppb, 20 ppb and 25 ppb for ethane, propane and acetylene respectively. Between the NMHCs being monitored

  11. A Test of a Strong Ground Motion Prediction Methodology for the 7 September 1999, Mw=6.0 Athens Earthquake

    Energy Technology Data Exchange (ETDEWEB)

    Hutchings, L; Ioannidou, E; Voulgaris, N; Kalogeras, I; Savy, J; Foxall, W; Stavrakakis, G


    We test a methodology to predict the range of ground-motion hazard for a fixed magnitude earthquake along a specific fault or within a specific source volume, and we demonstrate how to incorporate this into probabilistic seismic hazard analyses (PSHA). We modeled ground motion with empirical Green's functions. We tested our methodology with the 7 September 1999, Mw=6.0 Athens earthquake, we: (1) developed constraints on rupture parameters based on prior knowledge of earthquake rupture processes and sources in the region; (2) generated impulsive point shear source empirical Green's functions by deconvolving out the source contribution of M < 4.0 aftershocks; (3) used aftershocks that occurred throughout the area and not necessarily along the fault to be modeled; (4) ran a sufficient number of scenario earthquakes to span the full variability of ground motion possible; (5) found that our distribution of synthesized ground motions span what actually occurred and their distribution is realistically narrow; (6) determined that one of our source models generates records that match observed time histories well; (7) found that certain combinations of rupture parameters produced ''extreme'' ground motions at some stations; (8) identified that the ''best fitting'' rupture models occurred in the vicinity of 38.05{sup o} N 23.60{sup o} W with center of rupture near 12 km, and near unilateral rupture towards the areas of high damage, and this is consistent with independent investigations; and (9) synthesized strong motion records in high damage areas for which records from the earthquake were not recorded. We then developed a demonstration PSHA for a source region near Athens utilizing synthesized ground motion rather that traditional attenuation. We synthesized 500 earthquakes distributed throughout the source zone likely to have Mw=6.0 earthquakes near Athens. We assumed an average return period of 1000 years for this

  12. High Flux Isotope Reactor (HFIR) (United States)

    Federal Laboratory Consortium — The HFIR at Oak Ridge National Laboratory is a light-water cooled and moderated reactor that is the United States’ highest flux reactor-based neutron source. HFIR...

  13. Reactor operation environmental information document

    Energy Technology Data Exchange (ETDEWEB)

    Haselow, J.S.; Price, V.; Stephenson, D.E.; Bledsoe, H.W.; Looney, B.B.


    The Savannah River Site (SRS) produces nuclear materials, primarily plutonium and tritium, to meet the requirements of the Department of Defense. These products have been formed in nuclear reactors that were built during 1950--1955 at the SRS. K, L, and P reactors are three of five reactors that have been used in the past to produce the nuclear materials. All three of these reactors discontinued operation in 1988. Currently, intense efforts are being extended to prepare these three reactors for restart in a manner that protects human health and the environment. To document that restarting the reactors will have minimal impacts to human health and the environment, a three-volume Reactor Operations Environmental Impact Document has been prepared. The document focuses on the impacts of restarting the K, L, and P reactors on both the SRS and surrounding areas. This volume discusses the geology, seismology, and subsurface hydrology. 195 refs., 101 figs., 16 tabs.

  14. Managing change in educational organizations: managing and leading higher education in an era of change in Greece. Case study: University of Indianapolis, Athens.


    Kiritsis, Vasilios James


    This project attempts to contribute to the field of education, by presenting and analysing change and its management and how change has affected the operations of a foreign University branch. It describes a set of recommendations that will aid the case organization (University of Indianapolis Athens - UIA) and consequently educational organizations / institutions, in listing the various challenges affecting education and their operations in the 21st century. It is argued that identifying thes...

  15. Reactor operation safety information document

    Energy Technology Data Exchange (ETDEWEB)


    The report contains a reactor facility description which includes K, P, and L reactor sites, structures, operating systems, engineered safety systems, support systems, and process and effluent monitoring systems; an accident analysis section which includes cooling system anomalies, radioactive materials releases, and anticipated transients without scram; a summary of onsite doses from design basis accidents; severe accident analysis (reactor core disruption); a description of operating contractor organization and emergency planning; and a summary of reactor safety evolution. (MB)

  16. Determination of the priority substances regulated by 2000/60/EC and 2008/105/EC Directives in the surface waters supplying water treatment plants of Athens, Greece. (United States)

    Golfinopoulos, Spyros K; Nikolaou, Anastasia D; Thomaidis, Nikolaos S; Kotrikla, Anna Maria; Vagi, Maria C; Petsas, Andreas S; Lekkas, Demetris F; Lekkas, Themistokles D


    An investigation into the occurrence of priority substances regulated by 2000/60/EC Water Framework Directive and 2008/105/EC Directive was conducted for a period of one year in the surface water sources supplying the water treatment plants (WTPs) of Athens and in the raw water of WTPs. Samples from four reservoirs and four water treatment plants of Athens were taken seasonally. The substances are divided into seven specific groups, including eight volatile organic compounds (VOCs), diethylhexylphthalate, four organochlorine pesticides (OCPs), three organophosphorus/organonitrogen pesticides (OPPs/ONPs), four triazines and phenylurea herbicides, pentachlorophenol, and four metals. The aforementioned substances belong to different chemical categories, and different analytical methods were performed for their determination. The results showed that the surface waters that feed the WTPs of Athens are not burdened with significant levels of toxic substances identified as European Union (EU) priority substances. Atrazine, hexachlorocyclohexane, endosulfan, trifluralin, anthracene and 4-nonylphenol were occasionally observed at very low concentrations. Their presence in a limited number of cases could be attributed to waste disposal, agricultural activities, and to a limited industrial activity in the area nearby the water bodies.

  17. Fast reactor programme in India

    Indian Academy of Sciences (India)


    Sep 4, 2015 ... criteria; passive shutdown and decay heat removal systems; fast breeder reactors in India. PACS No. 28.41.−i. 1. ... water reactors, mainly pressurized heavy water reactors (PHWRs) to extract ∼10 GWe capacity for ..... commissioning phase and most of the supporting systems have been commissioned and.

  18. Engineering reactors for catalytic reactions

    Indian Academy of Sciences (India)

    Extensive studies have been conducted to establish sound basis for design and engineering of reactors for practising such catalytic reactions and for realizing improvements in reactor performance. In this article, application of recent (and not so recent) developments in engineering reactors for catalytic reactions is ...


    Whitham, G.K.; Smith, R.R.


    This patent shows a method for detecting leaks in jacketed fuel elements. The element is placed in a sealed tank within a nuclear reactor, and, while the reactor operates, the element is sparged with gas. The gas is then led outside the reactor and monitored for radioactive Xe or Kr. (AEC)

  20. Fast reactor programme in India

    Indian Academy of Sciences (India)


    Sep 4, 2015 ... Home; Journals; Pramana – Journal of Physics; Volume 85; Issue 3. Fast reactor programme in India. P Chellapandi P R ... Keywords. Sodium fast reactor; design challenges; construction challenges; emerging safety criteria; passive shutdown and decay heat removal systems; fast breeder reactors in India.

  1. Stabilized Spheromak Fusion Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, T


    The U.S. fusion energy program is focused on research with the potential for studying plasmas at thermonuclear temperatures, currently epitomized by the tokamak-based International Thermonuclear Experimental Reactor (ITER) but also continuing exploratory work on other plasma confinement concepts. Among the latter is the spheromak pursued on the SSPX facility at LLNL. Experiments in SSPX using electrostatic current drive by coaxial guns have now demonstrated stable spheromaks with good heat confinement, if the plasma is maintained near a Taylor state, but the anticipated high current amplification by gun injection has not yet been achieved. In future experiments and reactors, creating and maintaining a stable spheromak configuration at high magnetic field strength may require auxiliary current drive using neutral beams or RF power. Here we show that neutral beam current drive soon to be explored on SSPX could yield a compact spheromak reactor with current drive efficiency comparable to that of steady state tokamaks. Thus, while more will be learned about electrostatic current drive in coming months, results already achieved in SSPX could point to a productive parallel development path pursuing auxiliary current drive, consistent with plans to install neutral beams on SSPX in the near future. Among possible outcomes, spheromak research could also yield pulsed fusion reactors at lower capital cost than any fusion concept yet proposed.

  2. Nuclear Reactors and Technology

    Energy Technology Data Exchange (ETDEWEB)

    Cason, D.L.; Hicks, S.C. [eds.


    This publication Nuclear Reactors and Technology (NRT) announces on a monthly basis the current worldwide information available from the open literature on nuclear reactors and technology, including all aspects of power reactors, components and accessories, fuel elements, control systems, and materials. This publication contains the abstracts of DOE reports, journal articles, conference papers, patents, theses, and monographs added to the Energy Science and Technology Database during the past month. Also included are US information obtained through acquisition programs or interagency agreements and international information obtained through the International Energy Agency`s Energy Technology Data Exchange or government-to-government agreements. The digests in NRT and other citations to information on nuclear reactors back to 1948 are available for online searching and retrieval on the Energy Science and Technology Database and Nuclear Science Abstracts (NSA) database. Current information, added daily to the Energy Science and Technology Database, is available to DOE and its contractors through the DOE Integrated Technical Information System. Customized profiles can be developed to provide current information to meet each user`s needs.

  3. Nuclear reactor building (United States)

    Gou, P.F.; Townsend, H.E.; Barbanti, G.


    A reactor building for enclosing a nuclear reactor includes a containment vessel having a wetwell disposed therein. The wetwell includes inner and outer walls, a floor, and a roof defining a wetwell pool and a suppression chamber disposed there above. The wetwell and containment vessel define a drywell surrounding the reactor. A plurality of vents are disposed in the wetwell pool in flow communication with the drywell for channeling into the wetwell pool steam released in the drywell from the reactor during a LOCA for example, for condensing the steam. A shell is disposed inside the wetwell and extends into the wetwell pool to define a dry gap devoid of wetwell water and disposed in flow communication with the suppression chamber. In a preferred embodiment, the wetwell roof is in the form of a slab disposed on spaced apart support beams which define there between an auxiliary chamber. The dry gap, and additionally the auxiliary chamber, provide increased volume to the suppression chamber for improving pressure margin. 4 figures.


    Smith, K.F.; Van Thyne, R.J.


    A fuel element is described for fast reactors comprised of a core of uranium metal containing material and a jacket around the core, the jacket consisting of from 2.5 to 15 percent of titanium, from 1 to 5 percent of niobium, and from 80 to 96.5 percent of vanadium.

  5. Nuclear rocket engine reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lanin, Anatoly


    Covers a new technology of nuclear reactors and the related materials aspects. Integrates physics, materials science and engineering Serves as a basic book for nuclear engineers and nuclear physicists. The development of a nuclear rocket engine reactor (NRER) is presented in this book. The working capacity of an active zone NRER under mechanical and thermal load, intensive neutron fluxes, high energy generation (up to 30 MBT/l) in a working medium (hydrogen) at temperatures up to 3100 K is displayed. Design principles and bearing capacity of reactors area discussed on the basis of simulation experiments and test data of a prototype reactor. Property data of dense constructional, porous thermal insulating and fuel materials like carbide and uranium carbide compounds in the temperatures interval 300 - 3000 K are presented. Technological aspects of strength and thermal strength resistance of materials are considered. The design procedure of possible emergency processes in the NRER is developed and risks for their origination are evaluated. Prospects of the NRER development for pilotless space devices and piloted interplanetary ships are viewed.

  6. WATER BOILER REACTOR (United States)

    King, L.D.P.


    As its name implies, this reactor utilizes an aqueous solution of a fissionable element salt, and is also conventional in that it contains a heat exchanger cooling coil immersed in the fuel. Its novelty lies in the utilization of a cylindrical reactor vessel to provide a critical region having a large and constant interface with a supernatant vapor region, and the use of a hollow sleeve coolant member suspended from the cover assembly in coaxial relation with the reactor vessel. Cool water is circulated inside this hollow coolant member, and a gap between its outer wall and the reactor vessel is used to carry off radiolytic gases for recombination in an external catalyst chamber. The central passage of the coolant member defines a reflux condenser passage into which the externally recombined gases are returned and condensed. The large and constant interface between fuel solution and vapor region prevents the formation of large bubbles and minimizes the amount of fuel salt carried off by water vapor, thus making possible higher flux densities, specific powers and power densities.

  7. Fossil fuel furnace reactor (United States)

    Parkinson, William J.


    A fossil fuel furnace reactor is provided for simulating a continuous processing plant with a batch reactor. An internal reaction vessel contains a batch of shale oil, with the vessel having a relatively thin wall thickness for a heat transfer rate effective to simulate a process temperature history in the selected continuous processing plant. A heater jacket is disposed about the reactor vessel and defines a number of independent controllable temperature zones axially spaced along the reaction vessel. Each temperature zone can be energized to simulate a time-temperature history of process material through the continuous plant. A pressure vessel contains both the heater jacket and the reaction vessel at an operating pressure functionally selected to simulate the continuous processing plant. The process yield from the oil shale may be used as feedback information to software simulating operation of the continuous plant to provide operating parameters, i.e., temperature profiles, ambient atmosphere, operating pressure, material feed rates, etc., for simulation in the batch reactor.


    Fermi, E.; Zinn, W.H.


    The reactor radiation shield material is comprised of alternate layers of iron-containing material and compressed cellulosic material, such as masonite. The shielding material may be prefabricated in the form of blocks, which can be stacked together in ary desired fashion to form an effective shield.

  9. Neutronic Reactor Structure (United States)

    Vernon, H. C.; Weinberg, A. M.


    The neutronic reactor is comprised of a core consisting of natural uranium and heavy water with a K-factor greater than unity. The core is surrounded by a reflector consisting of natural uranium and ordinary water with a Kfactor less than unity. (AEC)


    Beaver, R.J.; Leitten, C.F. Jr.


    A boron-10 containing reactor control element wherein the boron-10 is dispersed in a matrix material is describeri. The concentration of boron-10 in the matrix varies transversely across the element from a minimum at the surface to a maximum at the center of the element, prior to exposure to neutrons. (AEC)

  11. Thermal Reactor Safety

    Energy Technology Data Exchange (ETDEWEB)


    Information is presented concerning fire risk and protection; transient thermal-hydraulic analysis and experiments; class 9 accidents and containment; diagnostics and in-service inspection; risk and cost comparison of alternative electric energy sources; fuel behavior and experiments on core cooling in LOCAs; reactor event reporting analysis; equipment qualification; post facts analysis of the TMI-2 accident; and computational methods.

  12. Research on the reactor physics and reactor safety of VVER reactors. AER Symposium 2016

    Energy Technology Data Exchange (ETDEWEB)

    Kliem, S.


    The selected paperscan be attributed to the following main subjects: Reactor start-up tests and use of corresponding data for code validation, code development and application, approaches for safety analyses, closure of nuclear fuel cycle, prospective reactor concepts.

  13. Sequencing Bacth Reactors; Reactores biologicos secuenciados

    Energy Technology Data Exchange (ETDEWEB)

    Nolasco, D.; Manoharan, M.


    The application of sequencing batch reactors (SBR) for wastewater treatment is becoming increasingly popular. However, published information on process performance and construction costs for SBRs is scarce. For this reason. Environment Canada, the Ontario Ministry of the Environment (MOE), and the Water Environment Association of Ontario (WEAO) decided to sponsor a program to evaluate the performance of 75 municipal SBRs in Canada and the United States. Effluent quality, construction costs, and design and operating problems were investigated. Areas for optimization found as a result of this investigation were classified an prioritized based on their impact on operational costs, treatment capacity, effluent quality, and frequency of occurrence. A list of recommendations for process optimization was prepared. A construction cost comparison between activated sludge systems of continuous flow and SBRs was prepared. (Author) 12 refs.

  14. Avispora mochogalegoi n. sp. (Apicomplexa: Sarcocystidae) in the little owl, Athene noctua (Strigiformes: Strigidae), in mainland Portugal. (United States)

    Cardozo, Sergian Vianna; Berto, Bruno Pereira; Caetano, Inês; Maniero, Viviane Camara; Santos, Marcos; Fonseca, Isabel Pereira da; Lopes, Carlos Wilson Gomes


    The little owl Athene noctua (Scopoli, 1769) is a small raptor that is widely distributed from northern to southern Portugal and several other countries in Europe, Asia and North Africa, and which has been introduced into New Zealand. In the current study, 18 fecal samples were collected from little owls kept at the Lisbon Center for Wild Animal Recovery, which is located in Monsanto Forest Park, Lisbon, Portugal. Twelve (67%) of them were found to be passing an undescribed species of Avispora in their feces. The oocysts of Avispora mochogalegoi n. sp. were ellipsoidal with a bilayered wall and measured 38.9 × 32.9 µm, with a shape index of 1.18. No micropyle, oocyst residuum or polar granule was present. The sporocysts were subspherical, measuring 21.1 × 20.1 µm. Stieda, sub-Stieda and para-Stieda bodies were absent. The sporocyst residuum was composed of a compact subspherical mass of granules. This is the fourth species of Avispora reported in Strigiformes.

  15. Avispora mochogalegoi n. sp. (Apicomplexa: Sarcocystidae in the little owl, Athene noctua (Strigiformes: Strigidae, in mainland Portugal

    Directory of Open Access Journals (Sweden)

    Sergian Vianna Cardozo

    Full Text Available Abstract The little owl Athene noctua (Scopoli, 1769 is a small raptor that is widely distributed from northern to southern Portugal and several other countries in Europe, Asia and North Africa, and which has been introduced into New Zealand. In the current study, 18 fecal samples were collected from little owls kept at the Lisbon Center for Wild Animal Recovery, which is located in Monsanto Forest Park, Lisbon, Portugal. Twelve (67% of them were found to be passing an undescribed species of Avispora in their feces. The oocysts of Avispora mochogalegoi n. sp. were ellipsoidal with a bilayered wall and measured 38.9 × 32.9 µm, with a shape index of 1.18. No micropyle, oocyst residuum or polar granule was present. The sporocysts were subspherical, measuring 21.1 × 20.1 µm. Stieda, sub-Stieda and para-Stieda bodies were absent. The sporocyst residuum was composed of a compact subspherical mass of granules. This is the fourth species of Avispora reported in Strigiformes.

  16. Home range and habitat use of little owl (Athene noctua in an agricultural landscape in coastal Catalonia, Spain

    Directory of Open Access Journals (Sweden)

    Framis, H.


    Full Text Available In recent decades agricultural landscapes in Catalonia have undergone a profound transformation as in most of Europe. Reforestation and urban development have reduced farmland and therefore the availability of suitable habitat for some bird species such as the little owl (Athene noctua. The outskirts of the city of Mataró by the Mediterranean Sea exemplify this landscape change, but still support a population of little owl where agriculture is carried out. Three resident little owls were monitored with telemetry weekly from November 2007 until the beginning of August 2008 in this suburban agricultural landscape. Mean home range ± SD was 10.9 ± 5.5 ha for minimum convex polygon (MCP100 and 7.4 ± 3.8 ha for Kernel 95% probability function (K95. Home ranges of contiguous neighboring pairs overlapped 18.4% (MCP100 or 6% (K95. Home range varied among seasons reaching a maximum between March and early August but always included the nesting site. Small forested patches were associated with roosting and nesting areas where cavities in Carob trees (Ceratonia siliqua were important. When foraging in crop fields, the owls typically fed where crops had recently been harvested and replanted. All three owls bred successfully.

  17. A case of leucism in the burrowing owl Athene cunicularia (Aves: Strigiformes with confirmation of species identity using cytogenetic analysis

    Directory of Open Access Journals (Sweden)

    Denise M Nogueira


    Full Text Available Leucism is an inherited disorder, characterized by the lack of pigments in part or all of the body, normal coloration of the eyes and, in birds, in naked parts such as the bill and legs. This kind of disorder is sometimes erroneously designated as albinism or partial albinism. In this study, we present a case of leucism in a wild owl. The studied individual presented completely white plumage, light-yellow coloration of legs and bill and normal coloration of eyes. According to morphological features, this owl is a specimen of burrowing owl, Athene cunicularia (Molina, 1782. To confirm the species identity, we used cytogenetic analyses for karyotypic determination, comparing it to the previously described one in the literature. We also studied a captive female of A. cunicularia to complement the species karyotype, which was described in the literature based only on a single male. The karyotype of the leucistic owl individual was compatible with the previously published one for A. cunicularia, confirming the bird was a male specimen. Cytogenetic analysis of the captive female showed that the W sex chromosome is metacentric and comparable to the seventh pair in size. This is the first description of a case of leucism in A. cunicularia for South America. Long-term studies are needed in the Neotropical region to evaluate survival and breeding success in leucistic birds.

  18. Signs for secondary buildup of heavy metals in soils at the periphery of Athens International Airport, Greece. (United States)

    Massas, Ioannis; Gasparatos, Dionisios; Ioannou, Dafni; Kalivas, Dionisios


    Emissions from civil airports are similar to those observed in industrial and urban areas. While air pollution and noise levels are regularly monitored and assessed, information on the status of heavy metals in soils close to airport facilities is limited. In this study, we monitored and assessed heavy metal distribution in soils close to Athens International Airport (AIA) in Attica, Greece. Following a grid sampling scenario, topsoil samples were collected from 86 sites at the periphery of AIA and total and available forms of Cu, Zn, Fe, Mn, Ni, Cr, Pb, and Ba concentrations were determined in aqua regia and DTPA soil extracts, respectively. Median concentration values for both metal forms are not considered as particularly high. However, 90th percentile concentration values for some metals are high, indicating soil enrichment. Evaluation of enrichment factor (EF) and availability ratio (AR) values and EFs spatial distribution have led to consistent conclusions of secondary and ongoing metal accumulation in the soils of the studied area. Tessier sequential extraction procedure was applied to 10% of the soil samples and the results showed high potential availability of Pb, Mn, Cu, and Ni, further supporting the continuous metal accumulation in the studied soils.

  19. CCN Activity, Variability and Influence on Droplet Formation during the HygrA-Cd Campaign in Athens

    Directory of Open Access Journals (Sweden)

    Aikaterini Bougiatioti


    Full Text Available Measurements of cloud condensation nuclei (CCN concentrations (cm−3 at five levels of supersaturation between 0.2–1%, together with remote sensing profiling and aerosol size distributions, were performed at an urban background site of Athens during the Hygroscopic Aerosols to Cloud Droplets (HygrA-CD campaign. The site is affected by local emissions and long-range transport, as portrayed by the aerosol size, hygroscopicity and mixing state. Application of a state-of-the-art droplet parameterization is used to link the observed size distribution measurements, bulk composition, and modeled boundary layer dynamics with potential supersaturation, droplet number, and sensitivity of these parameters for clouds forming above the site. The sensitivity is then used to understand the source of potential droplet number variability. We find that the importance of aerosol particle concentration levels associated with the background increases as vertical velocities increase. The updraft velocity variability was found to contribute 58–90% (68.6% on average to the variance of the cloud droplet number, followed by the variance in aerosol number (6–32%, average 23.2%. Therefore, although local sources may strongly modulate CCN concentrations, their impact on droplet number is limited by the atmospheric dynamics expressed by the updraft velocity regime.

  20. On the influence of the urban heat island on the cooling load of a school building in Athens, Greece (United States)

    Bagiorgas, H. S.; Mihalakakou, G.


    The present study investigates the effect of the urban heat island (UHI) phenomenon, measured in the Greater Athens Area (GAA), on the energy consumption of a typical modern school building. The energy performance of the selected building has been calculated using an accurate, extensively validated, transient simulation model for 17 different sites of the GAA, for the summer period. Calculations showed that the urban heat island phenomenon affects remarkably the thermal behavior of the school building, as suburban areas presented much lower cooling loads. The cooling load values fluctuated between 3304.3 kWh for the rural stations and 14,585.1 kWh for the central stations (for the year 2011) or between 3206.5 kWh and 14,208.3 kWh (for the year 2012), respectively. Moreover, the mean monthly cooling load values varied between 0.4-2 kWh/m2 for the rural stations and 4-6.9 kWh/m2 for the central stations, for the selected time period. Furthermore, a neural network model was designed and developed in order to quantify the contribution of various meteorological parameters (such as the mean daily air temperature values, the mean daily solar radiation values, the average wind speed and the urban heat island intensity) to the energy consumption of the building and it was found that the urban heat island intensity is the predominant parameter, influencing remarkably the energy consumption of the typical school building.

  1. Seasonal differences in thermal sensation in the outdoor urban environment of Mediterranean climates - the example of Athens, Greece (United States)

    Tseliou, Areti; Tsiros, Ioannis X.; Nikolopoulou, Marialena


    Outdoor urban areas are very important for cities and microclimate is a critical parameter in the design process, contributing to thermal comfort which is important for urban developments. The research presented in this paper is part of extensive field surveys conducted in Athens aimed at investigating people's thermal sensation in a Mediterranean city. Based on 2313 questionnaires and microclimatic data the current work focuses on the relative frequencies of people's evaluation of the thermal along with the sun and wind sensations between two seasons trying to identify the seasonal differences in thermal sensation. The impact of basic meteorological factors on thermal discomfort with respect to season are also examined, as well as the use of the outdoor environment. Results show that psychological adaptation is an important contributing factor influencing perception of the thermal environment between seasons. In addition, the thermal sensation votes during the cool months show that individuals are satisfied to a great extend with the thermal environment whereas the combination of high air temperature, strong solar radiation and weak wind lead to thermal discomfort during summertime. As far as the appropriate urban design in the Mediterranean climate is concerned, priority should be given to the warm months of the year.

  2. Development and application of Artificial Neural Networks in the forecast of maximum daily precipitation at Athens, Greece (United States)

    Nastos, P. T.; Paliatsos, A. G.; Larissi, I. K.; Moustris, K. P.


    Extreme daily precipitation events are involved in significant environmental damages, because of causing adverse impacts, such as flash floods, in urban and even in rural areas. Thus, long-term forecast of such events is of great importance, in order the local authorities be prepared to confront and mitigate the adverse consequences. The objective of this study is the possibility to forecast the maximum daily precipitation for the next coming year. For this reason, appropriate prognostic models, such as Artificial Neural Networks (ANN) were developed and applied. The data used for the analysis concern daily precipitation totals, which have been recorded at National Observatory of Athens (NOA), during the period 1891-2009. To evaluate the potential of precipitation prediction by the trained ANNs, a different period was used than the one used for the training for each station. The datasets of the period 1891-1980 were used as training datasets, while the datasets of the period 1981-2009 were used as validation datasets. Appropriate statistical indexes, such as the coefficient of determination (R2), the index of agreement (IA) and the root mean square error (RMSE), were applied to test the reliability of the predictive models. The findings of the analysis showed that, the forecasted maximum daily precipitation totals for the next coming year compared to the respective original ones indicated a quite satisfactory relationship, at the statistically significant level p<0.01.

  3. Urban aerosol mapping over Athens using the differential textural analysis (DTA) algorithm on MERIS-ENVISAT data (United States)

    Retalis, Adrianos; Sifakis, Nicolaos


    Low and moderate spatial resolution satellite sensors (such as TOMS, AVHRR, SeaWiFS) have already shown their capability in tracking aerosols at a global scale. Sensors with moderate to high spatial resolution (such as MODIS and MERIS) seem also to be appropriate for aerosol retrieval at a regional scale. We investigated in this study the potential of MERIS-ENVISAT data to resolve the horizontal spatial distribution of aerosols over urban areas, such as the Athens metropolitan area, by using the differential textural analysis (DTA) code. The code was applied to a set of geo-corrected images to retrieve and map aerosol optical thickness (AOT) values relative to a reference image assumed to be clean of pollution with a homogeneous atmosphere. The comparison of satellite retrieved AOT against PM10 data measured at ground level showed a high positive correlation particularly for the AOT values calculated using the 5th MERIS' spectral band (R2=0.83). These first results suggest that the application of the DTA code on cloud free areas of MERIS images can be used to provide AOT related to air quality in this urban region. The accuracy of retrieved AOT mainly depends on the overall quality, the pollution cleanness and the atmospheric homogeneity of the reference image.

  4. Results of the DUE Thermopolis Campaign with Regard to the Urban Heat Island (UHI) Effect in Athens (United States)

    Daglis, Ioannis A.; Rapsomanikis, Spyridon; Kourtidis, Konstantinos; Melas, Dimitrios; Papayannis, Alexandros; Keramitsoglou, Iphigenia; Giannaros, Theodoros; Amiridis, Vassilis; Petropoulos, Georgios; Georgoulias, Aristeidis; Sobrino, Jose Antonio; Manunta, Paolo; Grobner, Julian; Paganini, Marc; Bianchi, Remo


    The Urban Heat Island (UHI) effect is a typical phenomenon of urban climate, where the temperature of central urban locations is several degrees higher than that of surrounding rural areas of similar elevation; the temperature difference is especially pronounced during night-time. Although the UHI effect has long been studied through ground-based observations, the possibility of thermal remote sensing using spacecraft and/or airborne platforms has become available only relatively recently, providing innovative ways for the observation and study of the UHI effect. Following an initiative of the European Space Agency (ESA) to improve our understanding of the complexities of how urban heat islands arise, a relevant project entitled "Urban Heat Islands and Urban Thermography" has been under way to study the UHI effect in major European cities through the combination of ground-based observations and spacecraft remote sensing. In this paper we report preliminary results of this project pertaining to the metropolitan area of Athens, Greece, where also airborne remote sensing observations became available through the ESA-funded Thermopolis 2009 campaign, coordinated by the Democritus University of Thrace and implemented by a wide consortium

  5. Synergies between Urban Heat Island and Heat Waves in Athens (Greece), during an extremely hot summer (2012). (United States)

    Founda, Dimitra; Santamouris, Mattheos


    Heat waves (HWs) are recognized as a serious threat for human health worldwide, with urban areas being more vulnerable due to the urban heat island (UHI) effect and population density. Yet, in the climate change context, HWs are becoming more frequent, stronger and longer, which, coupled with intensifying urbanization exacerbates thermal risk for urban residents. Despite the profound impact of this global phenomenon there is no clear consensus so far on possible synergies between UHIs and HWs. The study sheds light on the complex synergies between UHIs and HWs focusing on coastal sites. A quite challenging period comprising five HW episodes during summer 2012 in Athens (Greece) was selected for analysis. A positive feedback between UHIs and HWs was found, with intensification of the average UHI magnitude by up to 3.5 °C during HWs, compared to summer background conditions. Our results contribute significantly to understanding synergies between UHIs and HWs that may strongly increase thermal risk in cities and vulnerability of urban population.

  6. From hygroscopic aerosols to cloud droplets: The HygrA-CD campaign in the Athens basin - An overview. (United States)

    Papayannis, A; Argyrouli, A; Bougiatioti, A; Remoundaki, E; Vratolis, S; Nenes, A; Solomos, S; Komppula, M; Giannakaki, E; Kalogiros, J; Banks, R; Eleftheriadis, K; Mantas, E; Diapouli, E; Tzanis, C G; Kazadzis, S; Binietoglou, I; Labzovskii, L; Vande Hey, J; Zerefos, C S


    The international experimental campaign Hygroscopic Aerosols to Cloud Droplets (HygrA-CD), organized in the Greater Athens Area (GAA), Greece from 15 May to 22 June 2014, aimed to study the physico-chemical properties of aerosols and their impact on the formation of clouds in the convective Planetary Boundary Layer (PBL). We found that under continental (W-NW-N) and Etesian (NE) synoptic wind flow and with a deep moist PBL (~2-2.5km height), mixed hygroscopic (anthropogenic, biomass burning and marine) particles arrive over the GAA, and contribute to the formation of convective non-precipitating PBL clouds (of ~16-20μm mean diameter) with vertical extent up to 500m. Under these conditions, high updraft velocities (1-2ms(-1)) and cloud condensation nuclei (CCN) concentrations (~2000cm(-3) at 1% supersaturation), generated clouds with an estimated cloud droplet number of ~600cm(-3). Under Saharan wind flow conditions (S-SW) a shallow PBL (<1-1.2km height) develops, leading to much higher CCN concentrations (~3500-5000cm(-3) at 1% supersaturation) near the ground; updraft velocities, however, were significantly lower, with an estimated maximum cloud droplet number of ~200cm(-3) and without observed significant PBL cloud formation. The largest contribution to cloud droplet number variance is attributed to the updraft velocity variability, followed by variances in aerosol number concentration. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. The Epidemiology of Pulmonary Nontuberculous Mycobacteria: Data from a General Hospital in Athens, Greece, 2007–2013

    Directory of Open Access Journals (Sweden)

    Marios Panagiotou


    Full Text Available Background. The epidemiology of pulmonary nontuberculous mycobacteria (NTM in Greece is largely unknown. Objectives. To determine the incidence and the demographic, microbiological, and clinical characteristics of patients with pulmonary NTM infection and pulmonary NTM disease. Methods. A retrospective review of the demographic, microbiological, and clinical characteristics of patients with NTM culture-positive respiratory specimens from January 2007 to May 2013. Results. A total of 120 patients were identified with at least one respiratory NTM isolate and 56 patients (46% fulfilled the microbiological ATS/IDSA criteria for NTM disease. Of patients with adequate data, 16% fulfilled the complete ATS/IDSA criteria for NTM disease. The incidence of pulmonary NTM infection and disease was 18.9 and 8.8 per 100.000 inpatients and outpatients, respectively. The spectrum of NTM species was high (13 species and predominated by M. avium-intracellulare complex (M. avium (13%, M. intracellulare (10%, M. gordonae (14%, and M. fortuitum (12%. The ratio of isolation of NTM to M. tuberculosis in all hospitalized patients was 0.59. Conclusions. The first data on the epidemiology of pulmonary NTM in Athens, Greece, are presented. NTM infection is common in patients with chronic respiratory disease. However, only a significantly smaller proportion of patients fulfill the criteria for NTM disease.

  8. Attitudes towards depression, psychiatric medication and help-seeking intentions amid financial crisis: Findings from Athens area. (United States)

    Economou, Marina; Bergiannaki, Joanna Despina; Peppou, Lily Evangelia; Karayanni, Ismini; Skalkotos, George; Patelakis, Athanasios; Souliotis, Kyriakos; Stefanis, Costas


    The financial crisis has yielded adverse effects on the population worldwide, as evidenced by elevated rates of major depression. International recommendations for offsetting the mental health impact of the recession highlight the need for effective treatment, including reduction in the stigma attached to the disorder. This study endeavoured to explore lay attitudes to depression and psychiatric medication during a period of financial crisis and to identify their correlates. Furthermore, it investigated their link to help-seeking intentions. A random and representative sample of 621 respondents from Athens area participated in the study (Response Rate = 81.7%). The telephone interview schedule consisted of the Personal Stigma Scale, a self-constructed scale tapping attitudes to psychiatric medication and one question addressing help-seeking intentions. The preponderant stigmatising belief about depression pertains to perceiving the disorder as a sign of personal weakness. In addition, stereotypes of unpredictability and dangerousness were popular among the sample. Nonetheless, stigmatising beliefs are much stronger with regard to psychiatric medication; perceived as addictive, capable of altering one's personality, less effective than homeopathic remedies and doing more harm than good. Help-seeking intentions were predicted by education, unemployment and attitudes to psychiatric medication solely. Research on the mental health effects of the global recession should encompass studies investigating the stigma attached to mental disorders and its implications. © The Author(s) 2016.

  9. Distributional changes in the western Burrowing Owl (Athene cunicularia hypugaea) in North America from 1967 to 2008 (United States)

    Macias-Duarte, Alberto; Conway, Courtney J.


    The quantification of shifts in bird distributions in response to climate change provides an opportunity to gain a deeper understanding of the processes that influence species persistence. We used data from the North American Breeding Bird Survey (BBS) to document changes in the distributional limits of the western Burrowing Owl (Athene cunicularia hypugaea) from 1967 to 2008. We used logistic regression to model presence probability (p) as a function of longitude, latitude, and year. We modeled a linear trend in logit(p) through time with slope and intercept modeled as a double Fourier series of longitude and latitude. We found that the western Burrowing Owl has experienced an intriguing southward shift in the northern half of its breeding range, contrary to what is predicted by most species niche models and what has been observed for many other species in North America. The breeding range of the Burrowing Owl has been shrinking near its northern, western, and eastern edges. Our model detected the population declines that were observed in California and eastern Washington, in locations where maps based on route-specific estimating equations had predicted significant population increases. We suggest that the northern boundary of the breeding distribution of the western Burrowing Owl has contracted southward and the southern boundary of the species' breeding distribution has expanded southward into areas of northern Mexico that were formerly used only by wintering migrants.

  10. CER. Research reactors in France

    Energy Technology Data Exchange (ETDEWEB)

    Estrade, Jerome [CEA, DEN, DER, Saint-Paul-lez-Durance (France). Jules Horowitz Reactor (JHR)


    Networking and the establishment of coalitions between research reactors are important to guarantee a high technical quality of the facility, to assure well educated and trained personnel, to harmonize the codes of standards and the know-ledge of the personnel as well as to enhance research reactor utilization. In addition to the European co-operation, country-specific working groups have been established for many years, such as the French research reactor Club d'Exploitants des Reacteurs (CER). It is the association of French research reactors representing all types of research reactors from zero power up to high flux reactors. CER was founded in 1990 and today a number of 14 research reactors meet twice a year for an exchange of experience. (orig.)

  11. Methanogenesis in Thermophilic Biogas Reactors

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær


    Methanogenesis in thermophilic biogas reactors fed with different wastes is examined. The specific methanogenic activity with acetate or hydrogen as substrate reflected the organic loading of the specific reactor examined. Increasing the loading of thermophilic reactors stabilized the process...... as indicated by a lower concentration of volatile fatty acids in the effluent from the reactors. The specific methanogenic activity in a thermophilic pilot-plant biogas reactor fed with a mixture of cow and pig manure reflected the stability of the reactor. The numbers of methanogens counted by the most...... against Methanothrix soehngenii or Methanothrix CALS-I in any of the thermophilic biogas reactors examined. Studies using 2-14C-labeled acetate showed that at high concentrations (more than approx. 1 mM) acetate was metabolized via the aceticlastic pathway, transforming the methyl-group of acetate...

  12. Derived release limits for the greek research reactor site based on a diagnostic atmospheric modeling system for irregular terrain. (United States)

    Varvayanni, M; Catsaros, N; Antonopoulos-Domis, M


    The upper limits for the rate of release of radionuclides into the atmosphere, i.e., the "derived release limits," are calculated for the Greek Research Reactor (GRR-1) in order to determine possible operational schemes compatible with the effective dose limits for the general population. GRR-1 is located at the northwestern foot of Hymettos Mountain and at the eastern border of the urbanized area of Athens basin. Due to the topographic complexity of the region, the meteorological and atmospheric dispersion calculations were based on a numerical modeling system that is especially designed to work over irregular terrains by using a prismatic unstructured grid. The calculation of derived release limits was made using guidelines and methods that conform to the system of dose limits prescribed by the European radiation protection regulations.

  13. Nuclear reactor construction with bottom supported reactor vessel (United States)

    Sharbaugh, John E.


    An improved liquid metal nuclear reactor construction has a reactor core and a generally cylindrical reactor vessel for holding a large pool of low pressure liquid metal coolant and housing the core within the pool. The reactor vessel has an open top end, a closed flat bottom end wall and a continuous cylindrical closed side wall interconnecting the top end and bottom end wall. The reactor also has a generally cylindrical concrete containment structure surrounding the reactor vessel and being formed by a cylindrical side wall spaced outwardly from the reactor vessel side wall and a flat base mat spaced below the reactor vessel bottom end wall. A central support pedestal is anchored to the containment structure base mat and extends upwardly therefrom to the reactor vessel and upwardly therefrom to the reactor core so as to support the bottom end wall of the reactor vessel and the lower end of the reactor core in spaced apart relationship above the containment structure base mat. Also, an annular reinforced support structure is disposed in the reactor vessel on the bottom end wall thereof and extends about the lower end of the core so as to support the periphery thereof. In addition, an annular support ring having a plurality of inward radially extending linear members is disposed between the containment structure base mat and the bottom end of the reactor vessel wall and is connected to and supports the reactor vessel at its bottom end on the containment structure base mat so as to allow the reactor vessel to expand radially but substantially prevent any lateral motions that might be imposed by the occurrence of a seismic event. The reactor construction also includes a bed of insulating material in sand-like granular form, preferably being high density magnesium oxide particles, disposed between the containment structure base mat and the bottom end wall of the reactor vessel and uniformly supporting the reactor vessel at its bottom end wall on the containment

  14. Reactor core stability monitoring method for BWR type reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kanemoto, Shigeru; Ebata, Shigeo.


    In an operation for a BWR type reactor, reactor power is usually increased or decreased by controlling both of control rods and reactor core flow rate. Under a certain condition, the reactor core is made unstable by the coupling of nuclear and thermohydrodynamic characteristics in the reactor. Therefore, the reactor power and the reactor core flow rate are changed within a range predetermined by a design calculation. However, if reactor core stability can be always measured and monitored, it is useful for safe operation, as well as an existent operation range can be extended to enable more effective operation. That is, autoregressive a coefficient is determined successively on real time based on fluctuation components of neutron flux signals. Based on the result, an amplification ratio, as a typical measure of the reactor core stability, is determined on a real time. A time constant of the successive calculation for the autoregressive coefficient can be made variable by the amplification ratio. Then, the amplification ratio is estimated at a constant accuracy. With such procedures, the reactor core stability can be monitored successively in an ON-line manner at a high accuracy, thereby enabling to improve the operation performance. (I.S.).

  15. Compact fusion reactors

    CERN Multimedia

    CERN. Geneva


    Fusion research is currently to a large extent focused on tokamak (ITER) and inertial confinement (NIF) research. In addition to these large international or national efforts there are private companies performing fusion research using much smaller devices than ITER or NIF. The attempt to achieve fusion energy production through relatively small and compact devices compared to tokamaks decreases the costs and building time of the reactors and this has allowed some private companies to enter the field, like EMC2, General Fusion, Helion Energy, Lawrenceville Plasma Physics and Lockheed Martin. Some of these companies are trying to demonstrate net energy production within the next few years. If they are successful their next step is to attempt to commercialize their technology. In this presentation an overview of compact fusion reactor concepts is given.


    Hammond, R.P.; Busey, H.M.


    Nuclear reactors of the homogeneous liquid fuel type are discussed. The reactor is comprised of an elongated closed vessel, vertically oriented, having a critical region at the bottom, a lower chimney structure extending from the critical region vertically upwardly and surrounded by heat exchanger coils, to a baffle region above which is located an upper chimney structure containing a catalyst functioning to recombine radiolyticallydissociated moderator gages. In operation the liquid fuel circulates solely by convection from the critical region upwardly through the lower chimney and then downwardly through the heat exchanger to return to the critical region. The gases formed by radiolytic- dissociation of the moderator are carried upwardly with the circulating liquid fuel and past the baffle into the region of the upper chimney where they are recombined by the catalyst and condensed, thence returning through the heat exchanger to the critical region.


    Fermi, E.; Szilard, L.


    A nuclear reactor of the air-cooled, graphite moderated type is described. The active core consists of a cubicle mass of graphite, approximately 25 feet in each dimension, having horizontal channels of square cross section extending between two of the opposite faces, a plurality of cylindrical uranium slugs disposed in end to end abutting relationship within said channels providing a space in the channels through which air may be circulated, and a cadmium control rod extending within a channel provided in the moderator. Suitable shielding is provlded around the core, as are also provided a fuel element loading and discharge means, and a means to circulate air through the coolant channels through the fuel charels to cool the reactor.


    Mims, L.S.


    A multi-purpose instrument for measuring neutron flux, coolant flow rate, and coolant temperature in a nuclear reactor is described. The device consists essentially of a hollow thimble containing a heat conducting element protruding from the inner wall, the element containing on its innermost end an amount of fissionsble materinl to function as a heat source when subjected to neutron flux irradiation. Thermocouple type temperature sensing means are placed on the heat conducting element adjacent the fissionable material and at a point spaced therefrom, and at a point on the thimble which is in contact with the coolant fluid. The temperature differentials measured between the thermocouples are determinative of the neutron flux, coolant flow, and temperature being measured. The device may be utilized as a probe or may be incorporated in a reactor core. (AE C)


    Wigner, E.P.; Creutz, E.C.


    A nuclear reactor comprising a pair of graphite blocks separated by an air gap is described. Each of the blocks contains a plurality of channels extending from the gap through the block with a plurality of fuel elements being located in the channels. Means are provided for introducing air into the gap between the graphite blocks and for exhausting the air from the ends of the channels opposite the gap.

  20. Gaseous fuel reactor research (United States)

    Thom, K.; Schneider, R. T.


    The paper reviews studies dealing with the concept of a gaseous fuel reactor and describes the structure and plans of the current NASA research program of experiments on uranium hexafluoride systems and uranium plasma systems. Results of research into the basic properties of uranium plasmas and fissioning gases are reported. The nuclear pumped laser is described, and the main results of experiments with these devices are summarized.


    Heckman, T.P.


    A nuclear power reactor of the type in which a liquid moderator-coolant is transformed by nuclear heating into a vapor that may be used to drive a turbo- generator is described. The core of this reactor comprises a plurality of freely suspended tubular fuel elements, called fuel element trains, within which nonboiling pressurized liquid moderator-coolant is preheated and sprayed through orifices in the walls of the trains against the outer walls thereof to be converted into vapor. Passage of the vapor ovcr other unwetted portions of the outside of the fuel elements causes the steam to be superheated. The moderatorcoolant within the fuel elements remains in the liqUid state, and that between the fuel elements remains substantiaily in the vapor state. A unique liquid neutron-absorber control system is used. Advantages expected from the reactor design include reduced fuel element failure, increased stability of operation, direct response to power demand, and circulation of a minimum amount of liquid moderatorcoolant. (A.G.W.)


    Mahlmeister, J.E.; Peck, W.S.; Haberer, W.V.; Williams, A.C.


    An improved core design for a sodium-cooled, graphitemoderated nuclear reactor is described. The improved reactor core comprises a number of blocks of moderator material, each block being in the shape of a regular prism. A number of channels, extending the length of each block, are disposed around the periphery. When several blocks are placed in contact to form the reactor core, the channels in adjacent blocks correspond with each other to form closed conduits extending the length of the core. Fuel element clusters are disposed in these closed conduits, and liquid coolant is forced through the annulus between the fuel cluster and the inner surface of the conduit. In a preferred embodiment of the invention, the moderator blocks are in the form of hexagonal prisms with longitudinal channels cut into the corners of the hexagon. The main advantage of an "edge-loaded" moderator block is that fewer thermal neutrons are absorbed by the moderator cladding, as compared with a conventional centrally loaded moderator block.

  3. Nuclear reactor sealing system (United States)

    McEdwards, James A.


    A liquid metal-cooled nuclear reactor sealing system. The nuclear reactor includes a vessel sealed at its upper end by a closure head. The closure head comprises at least two components, one of which is rotatable; and the two components define an annulus therebetween. The sealing system includes at least a first and second inflatable seal disposed in series in an upper portion of the annulus. The system further includes a dip seal extending into a body of insulation located adjacent a bottom portion of the closure head. The dip seal comprises a trough formed by a lower portion of one of the components, and a seal blade pendently supported from the other component and extending downwardly into the trough. A body of liquid metal is contained in the trough which submerges a portion of the seal blade. The seal blade is provided with at least one aperture located above the body of liquid metal for providing fluid communication between the annulus intermediate the dip seal and the inflatable seals, and a body of cover gas located inside the vessel. There also is provided means for introducing a purge gas into the annulus intermediate the inflatable seals and the seal blade. The purge gas is introduced in an amount sufficient to substantially reduce diffusion of radioactive cover gas or sodium vapor up to the inflatable seals. The purge gas mixes with the cover gas in the reactor vessel where it can be withdrawn from the vessel for treatment and recycle to the vessel.

  4. Nuclear research reactors in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Cota, Anna Paula Leite; Mesquita, Amir Zacarias, E-mail: aplc@cdtn.b, E-mail: amir@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)


    The rising concerns about global warming and energy security have spurred a revival of interest in nuclear energy, giving birth to a 'nuclear power renaissance' in several countries in the world. Particularly in Brazil, in the recent years, the nuclear power renaissance can be seen in the actions that comprise its nuclear program, summarily the increase of the investments in nuclear research institutes and the government target to design and build the Brazilian Multipurpose research Reactor (BMR). In the last 50 years, Brazilian research reactors have been used for training, for producing radioisotopes to meet demands in industry and nuclear medicine, for miscellaneous irradiation services and for academic research. Moreover, the research reactors are used as laboratories to develop technologies in power reactors, which are evaluated today at around 450 worldwide. In this application, those reactors become more viable in relation to power reactors by the lowest cost, by the operation at low temperatures and, furthermore, by lower demand for nuclear fuel. In Brazil, four research reactors were installed: the IEA-R1 and the MB-01 reactors, both at the Instituto de Pesquisas Energeticas Nucleares (IPEN, Sao Paulo); the Argonauta, at the Instituto de Engenharia Nuclear (IEN, Rio de Janeiro) and the IPR-R1 TRIGA reactor, at the Centro de Desenvolvimento da Tecnologia Nuclear (CDTN, Belo Horizonte). The present paper intends to enumerate the characteristics of these reactors, their utilization and current academic research. Therefore, through this paper, we intend to collaborate on the BMR project. (author)

  5. Egg characteristics and hatch performance of Athens Canadian Random Bred 1955 meat-type chickens and 2013 Cobb 500 broilers. (United States)

    Collins, K E; McLendon, B L; Wilson, J L


    Athens Canadian Random Bred (ACRB) chickens, a 1955 meat-type control strain, were incubated with the 2013 Cobb 500 broiler to determine differences in egg composition, conductance values, incubation duration, hatch performance, and yolk utilization. Unincubated ACRB eggs had greater percentage solids than Cobb 500 eggs. The ACRB eggs had a greater solid portion as yolk, whereas the Cobb 500 devoted more solid percentage to albumen. Percentage shell was not different between the strains, but ACRB eggs had 2.7% greater percentage moisture loss after 18 d of incubation than Cobb 500 eggs. Conductance, conductance constant, and conductance standardized to a 100 g egg weight basis were all higher for ACRB eggs than Cobb 500 eggs at 12 and 18 d of incubation. The Cobb 500 chicks hatched 6 h earlier than ACRB chicks. The Cobb 500 incubation duration was 498 h, and the ACRB incubation duration was 504 h. There was no difference between the strains for percentage infertile eggs, embryonic mortality, hatchability, or salable chicks. The ACRB chicks hatched with a smaller dried residual yolk sac as a percentage of chick weight compared with the Cobb 500. Both strains had an average relative yolk-free chick weight of 61% of average initial egg weight. Thus the Cobb 500 eggs had decreased gas exchange across the eggshell, which may have contributed to the earlier hatch and decreased yolk utilization. Modern Cobb 500 broiler embryonic metabolism appears to have either become more dependent on albumen rather than yolk or has become more efficient with yolk reserves during development. Broiler hatch performance does not appear to have changed over the past 58 yr. © 2014 Poultry Science Association Inc.

  6. Causes of admission of little owl (Athene noctua at a wildlife rehabilitation centre in Catalonia (Spain from 1995 to 2010

    Directory of Open Access Journals (Sweden)

    Molina–López, R. A.


    Full Text Available This retrospective study analyzes the causes of morbidity of little owl (Athene noctua admitted to the Wildlife Rehabilitation Centre of Torreferrussa from 1995 to 2010. A total of 1,427 little owls were included in the study, with an average of 89 cases per year (range: 73–116. As regards the sex category, 80.7% animals (1,152/1,427 were classified as undetermined gender, 9.1% (130/1,427 were sexed as females and 10.2% (145/1,427 as males. The overall age distribution according to the calendar year showed that 66.6% (951/1,427 of birds were ’1st calendar year and 16.6% (237/1,427 were ‘> 1 calendar year’. Age could not be determined in 16.7% of birds. Primary causes of admission were orphaned young (53.2%, unknown trauma (24.7%, impact with motor vehicles (5.6%, other cause (5.5%, undetermined (3.7%, illegally captive (2.1%, natural diseases (2.1%, and gunshot (1.1%. Within the breeding season the frequency of admissions due to traumas –unknown trauma (X2 = 147.108; p < 0.001– and impact with motor vehicles (X2 = 28.528; p < 0.001 and other cause (X2 = 11.420; p = 0.003 were the most important causes. In winter, admissions were mainly related to unknown trauma and gunshot. Over the fifteen years we observed a significant increase in the orphaned young category.

  7. Education status determines 10-year (2002-2012) survival from cardiovascular disease in Athens metropolitan area: the ATTICA study, Greece. (United States)

    Panagiotakos, Demosthenes; Georgousopoulou, Ekavi; Notara, Venetia; Pitaraki, Evangelia; Kokkou, Eleni; Chrysohoou, Christina; Skoumas, Yannis; Metaxa, Vassiliki; Pitsavos, Christos; Stefanadis, Christodoulos


    Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality worldwide, and educational level seems to be an important determinant of the disease occurrence. The aim of this work was to investigate the association between education status and 10-year incidence of CVD, controlling for various socio-demographic lifestyle and clinical factors. From May 2001 to December 2002, 1514 men and 1528 women (>18 years) without any clinical evidence of CVD or any other chronic disease, at baseline, living in greater Athens area, Greece, were enrolled. In 2011-2012, the 10-year follow-up was performed in 2583 participants (15% of the participants were lost to follow-up). Incidence of fatal or non-fatal CVD was defined according to WHO-ICD-10 criteria. Education status was measured in years of schooling. The 10-year incidence of CVD was 15.7% [95% confidence intervals (CI) 14.1%-17.4%], 19.7% in men and 11.7% in women (Pgender education (education (>12 years of schooling). People in the low education group had higher prevalence of hypertension, diabetes and dyslipidaemias, were more likely to be smokers and sedentary, had less healthy dietary habits, as compared with those in the high education group. When controlling for participants' medical history, smoking, dietary and lifestyle habits, low education was no longer significantly associated with CVD, illustrating the mediating effect of clinical and behavioural factors in the link between education and disease. It was of interest that low education status interacted with alcohol drinking, enhancing the adverse effect of low education on CVD risk (relative risk 1.44, 95% CI 0.94%-2.20%), after various adjustments made. In this study, it was concluded that low educational level was associated with increased CVD risk. This was mainly explained by the intermediate association of low education with unhealthy choices that consequently worsen clinical status. © 2015 John Wiley & Sons Ltd.

  8. Relationships between yolk androgens and nest density, laying date, and laying order in Western Burrowing Owls (Athene cunicularia hypugaea) (United States)

    Welty, J.L.; Belthoff, J.R.; Egbert, J.; Schwabl, H.


    Increases in yolk androgens within and among avian clutches have been correlated with decreased incubation time, increased aggression within a nest, increased begging behaviour, decreased immune response, and decreased life span. Although the mechanisms that lead to variability in yolk androgens within and between clutches are not completely known, yolk androgens can be a function of both social and environmental conditions. We were interested in if and how nesting density, laying date, and laying order influenced yolk androgens in Western Burrowing Owls (Athene cunicularia hypugaea (Bonaparte, 1825)) in which nest density varies considerably. In 2006 and 2007, we used radioimmunoassay to quantify the concentrations of testosterone, 5a-dihydrotestosterone, and androstenedione in the egg yolks from one early and one latelaid egg in 47 nests of Burrowing Owls located in the Morley Nelson Snake River Birds of Prey National Conservation Area in southern Idaho. Nesting density had no detectable effect on yolk androgens. Yolk androgens varied temporally and peaked in the middle of the laying season while being low before and after this time period. Within nests, late-laid eggs had higher testosterone and dihydrotestosterone than early-laid eggs; adrostendione exhibited a similar pattern in one but not both years of our study. It is possible that the seasonal pattern in yolk androgens that we observed is related to aspects of mate quality for females or declining chances of fledging success for later nesting females, whereas rises in egg androgens between early and late eggs within clutches could reflect a mechanism to assist nestlings from late-laid eggs that hatch one to several days after their siblings to better compete for resources within the nest or promote survival in the presence of larger siblings.

  9. Is aircraft noise exposure associated with cardiovascular disease and hypertension? Results from a cohort study in Athens, Greece. (United States)

    Dimakopoulou, Konstantina; Koutentakis, Konstantinos; Papageorgiou, Ifigeneia; Kasdagli, Maria-Iosifina; Haralabidis, Alexandros S; Sourtzi, Panayota; Samoli, Evangelia; Houthuijs, Danny; Swart, Wim; Hansell, Anna L; Katsouyanni, Klea


    We followed up, in 2013, the subjects who lived near the Athens International Airport and had participated in the cross-sectional multicountry HYENA study in 2004-2006. To evaluate the association of exposure to aircraft and road traffic noise with the incidence of hypertension and other cardiovascular outcomes. From the 780 individuals who participated in the cross-sectional study, 537 were still living in the same area and 420 accepted to participate in the follow-up. Aircraft and road traffic noise exposure was based on the estimations conducted in 2004-2006, linking geocoded residential addresses of the participants to noise levels. We applied multiple logistic regression and Cox proportional hazards models, adjusting for potential confounders. The incidence of hypertension was significantly associated with higher aircraft noise exposure during the night. Specifically, the OR for hypertension per 10 dB increase in Lnight aircraft noise exposure was 2.63 (95% CI 1.21 to 5.71). Doctor-diagnosed cardiac arrhythmia was significantly associated with Lnight aircraft noise exposure, when prevalent and incident cases were considered with an OR of 2.09 (95% CI 1.07 to 4.08). Stroke risk was also increased with increasing noise exposure but the association was not significant. Twenty-four-hour road traffic noise associations with the outcomes considered were weaker and less consistent. In conclusion, our cohort study suggests that long-term exposure to aircraft noise, particularly during the night, is associated with incident hypertension and possibly, also, cardiovascular effects. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  10. Development of a road transport emission inventory for Greece and the Greater Athens Area: effects of important parameters. (United States)

    Fameli, K M; Assimakopoulos, V D


    Traffic is considered one of the major polluting sectors and as a consequence a significant cause for the measured exceedances of ambient air quality limit values mainly in urban areas. The Greater Athens Area (located in Attica), the most populated area in Greece, faces severe air pollution problems due to the combination of high road traffic emissions, complex topography and local meteorological conditions. Even though several efforts were made to construct traffic emission inventories for Greece and Attica, still there is not a spatially and temporally resolved one, based on data from relevant authorities and organisations. The present work aims to estimate road emissions in Greece and Attica based on the top down approach. The programme COPERT 4 was used to calculate the annual total emissions from the road transport sector for the period 2006-2010 and an emission inventory for Greece and Attica was developed with high spatial (6 × 6 km(2) for Greece and 2 × 2 km(2) for Attica) and temporal (1-hour) resolutions. The results revealed that about 40% of national CO₂, CO, VOC and NMVOC values and 30% of NOx and particles are emitted in Attica. The fuel consumption and the subsequent reduction of annual mileage driven in combination with the import of new engine anti-pollution technologies affected CO₂, CO, VOC and NMVOC emissions. The major part of CO (56.53%) and CO₂ (66.15%) emissions was due to passenger cars (2010), while heavy duty vehicles (HDVs) were connected with NOx, PM₂.₅ and PM₁₀ emissions with 51.27%, 43.97% and 38.13% respectively (2010). The fleet composition, the penetration of diesel fuelled cars, the increase of urban average speed and the fleet renewal are among the most effective parameters towards the emission reduction strategies. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Chemical and spectroscopic investigation of the Raphael's cartoon of the School of Athens from the Pinacoteca Ambrosiana (United States)

    Ioele, Marcella; Sodo, Armida; Casanova Municchia, Annalaura; Ricci, Maria Antonietta; Russo, Alfonso Pio


    The cartoon of "The School of Athens", realized by the famous artist Raffaello Sanzio, is a masterpiece of Italian Renaissance. It is a full-scale (804 × 285 cm2) preparatory cartoon, stored at the Pinacoteca Ambrosiana (Milan, Italy). In order to characterize the cartoon and the drawing and to investigate its conservation state, several scientific analyses have been performed, both in situ and on sampled fragments. This multi-analytical approach has identified most of the materials used in the original drawing and in restored areas and provided a map of previous restoration works. Here we report the results obtained by Raman and FTIR spectroscopy, scanning electron microscopy equipped with X-ray micro-analysis (SEM-EDS), pH measurements and micro-chemical tests. pH measurements proved the absence of an acidic decay of the paper. The original paper from linen and hemp fibres is well preserved. It is filled with calcium carbonate and has received a light sizing with protein glue, now almost completely transformed into oxalates. 1797 French intervention paper is of lower quality and has been covered with a patina of lead white in Arabic gum, most likely in an attempt to match the colour to the tone of the original. Both papers are stuck to a support paper with flour glue (containing starch and gluten) and glued with the same adhesive to a canvas lining. In situ Raman spectroscopy has clearly shown that the original drawing was in charcoal and lead white, while the restored areas have been drawn using charcoal and graphite.

  12. From Kazimierz to Athens - three decades of tobacco control advancement in Europe: time to tobacco-caused diseases endgame

    Directory of Open Access Journals (Sweden)

    Witold Antoni Zatoński


    Full Text Available In the early 1990s the premature mortality of young and middle-aged adults in many countries of Central and Eastern Europe (CEE reached some of the highest levels in the world. It was not only twice higher than in the countries of Western Europe, but also above the rates of many developing countries, including China and India. The main cause underlying this health catastrophe in CEE were tobacco-caused diseases. In November 1990, almost precisely a year after the collapse of the Berlin Wall, a summit of tobacco control leaders took place in the town of Kazimierz in Poland. The aim of the meeting was to devise a strategy and plan of action that would allow to counteract the tobacco epidemic ravaging the post-communist states. The Kazimierz conference gathered leading tobacco control experts from across Europe and North America. Almost thirty years on from the Kazimierz Declaration, most of its health goals have been fully accomplished. The gap in smoking between young adults in CEE and Western Europe is almost closed, as evidenced by converging lung cancer morbidity and mortality rates. However, tobacco control in Europe is far from being finished business. There is an urgent need to formulate a new plan, akin to the Kazimierz Declaration in the early 1990s, that would allow tobacco control in Europe to take another leap forward. We need a Declaration of Athens that outlines the vision of civil society movement for tobacco end game, and the ENSP is best placed to launch such an initiative.

  13. A study of the hourly variability of the urban heat island effect in the Greater Athens Area during summer. (United States)

    Kourtidis, K; Georgoulias, A K; Rapsomanikis, S; Amiridis, V; Keramitsoglou, I; Hooyberghs, H; Maiheu, B; Melas, D


    Measurements of air temperature and humidity in the urban canopy layer during July 2009 in 26 sites in Athens, Greece, allowed for the mapping of the hourly spatiotemporal evolution of the urban heat island (UHI) effect. City districts neighboring to the mountains to the east were the hottest during the afternoon, while being among the coolest during the early morning hours. While during the early morning some coastal sites were the hottest, the warm air plume slowly moved to the densely urbanized center of the city until 14:00-15:00, moving then further west, to the Elefsis industrial area in the afternoon. Results from the UrbClim model agree fairly well with the observations. Satellite-derived land surface temperature (LST) data from AATSR, ASTER, AVHRR and MODIS, for pixels corresponding to ground stations measuring Tair, showed that LST can be up to 5K lower than the respective Tair during nighttime, while it can be up to 15K higher during the rest of the day. Generally, LST during late afternoon as acquired from AATSR is very near to Tair for all stations and all days, i.e., the AATSR LST afternoon retrieval can be used as a very good approximation of Tair. The hourly evolution of the spatial Tair distribution was almost the same during days with NE Etesian flow as in days with sea breeze circulation, indicating that the mean wind flow was not the main factor controlling the diurnal UHI evolution, although it influenced the temperatures attained. No unambiguous observation of the urban moisture excess (UME) phenomenon could be made. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Nuclear security and radiological preparedness for the olympic games, athens 2004: lessons learned for organizing major public events. (United States)

    Kamenopoulou, Vassiliki; Dimitriou, Panayiotis; Hourdakis, Constantine J; Maltezos, Antonios; Matikas, Theodore; Potiriadis, Constantinos; Camarinopoulos, Leonidas


    In light of the exceptional circumstances that arose from hosting the Olympic Games in Athens in 2004 and from recent terrorist events internationally, Greece attributes the highest priority to security issues. According to its statutory role, the Greek Atomic Energy Commission is responsible for emergency preparedness and response in case of nuclear and radiological events, and advises the Government on the measures and interventions necessary to protect the public. In this context, the Commission participated in the Nuclear, Radiological, Biological, and Chemical Threat National Emergency Plan, specially developed for the Olympic Games, and coordinated by the Olympic Games Security Division. The objective of this paper is to share the experience gained during the organization of the Olympic Games and to present the nuclear security program implemented prior to, during, and beyond the Games, in order to prevent, detect, assess, and respond to the threat of nuclear terrorism. This program adopted a multi-area coverage of nuclear security, including physical protection of nuclear and radiological facilities, prevention of smuggling of radioactive materials through borders, prevention of dispersion of these materials into the Olympic venues, enhancement of emergency preparedness and response to radiological events, upgrading of the technical infrastructure, establishment of new procedures for assessing the threat and responding to radiological incidents, and training personnel belonging to several organizations involved in the National Emergency Response Plan. Finally, the close cooperation of Greek Authorities with the International Atomic Energy Agency and the U.S. Department of Energy, under the coordination of the Greek Atomic Energy Commission, is also discussed.

  15. Standardized inspections of food premises during the 2004 Athens Olympic Games: descriptive analysis and risk factors for unsatisfactory results. (United States)

    Hadjichristodoulou, Christos; Mouchtouri, Varvara; Varzakas, Theodoros; Arvanitoyannis, Ioannis; Kremastinou, Jenny


    Standardized inspections of food premises are part of environmental health systems implemented worldwide. The food safety strategy for the 2004 Olympic Games included standardized inspections to ensure uniformity and consistency of procedures and effective electronic management of data. Inspections were carried out by 196 inspectors in the five Olympic cities: Athens, Thessalonica, Volos, Iraklio, and Patra. From January 2003 to September 2004, a total of 1,249 food premises were inspected. An unsatisfactory inspection result (C grade) was received by 347 (27.8%) food premises, a relatively satisfactory result (B grade) was received by 332 (26.6%), and a satisfactory result (A grade) was received by 570 (45.6%). About 16% of inspected premises did not hold a valid permit. Unsatisfactory inspection results were more frequent for premises located in the two largest Greek cities in comparison with the other smaller cities (relative risk = 1.95, 95% confidence interval [CI] = 1.36 to 2.80). Based on logistic regression analysis, unsatisfactory inspection results were positively associated with food premises that were not located on a ground floor (odds ratio [OR] = 2.56, 95% CI = 1.39 to 4.73) and negatively associated with application of hazard analysis critical control point (HACCP) principles (OR = 0.27, 95% CI = 0.10 to 0.71). Food hygiene education through formal training programs should be encouraged to improve compliance of food premises. Food premises located on hotel floors and serving buffet meals are at higher risk for unsatisfactory conditions. Businesses that implemented a HACCP system within their operations to ensure food safety operated under more hygienic conditions. Future inspections by Public Health Authorities should involve elements of audit after the legislation for the application of HACCP principles.

  16. Spiral-shaped disinfection reactors

    KAUST Repository

    Ghaffour, Noreddine


    This disclosure includes disinfection reactors and processes for the disinfection of water. Some disinfection reactors include a body that defines an inlet, an outlet, and a spiral flow path between the inlet and the outlet, in which the body is configured to receive water and a disinfectant at the inlet such that the water is exposed to the disinfectant as the water flows through the spiral flow path. Also disclosed are processes for disinfecting water in such disinfection reactors.

  17. Acceptability of reactors in space

    Energy Technology Data Exchange (ETDEWEB)

    Buden, D.


    Reactors are the key to our future expansion into space. However, there has been some confusion in the public as to whether they are a safe and acceptable technology for use in space. The answer to these questions is explored. The US position is that when reactors are the preferred technical choice, that they can be used safely. In fact, it dies not appear that reactors add measurably to the risk associated with the Space Transportation System.

  18. Neutrino Oscillation Studies with Reactors

    CERN Document Server

    Vogel, Petr; Zhang, Chao


    Nuclear reactors are one of the most intense, pure, controllable, cost-effective, and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavors are quantum mechanical mixtures. Over the past several decades reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle $\\theta_{13}$. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.

  19. The combined effect of reduced fossil fuel consumption and increasing biomass combustion on Athens' air quality, as inferred from long term CO measurements. (United States)

    Gratsea, Myrto; Liakakou, Eleni; Mihalopoulos, Nikos; Adamopoulos, Anastasios; Tsilibari, Eirini; Gerasopoulos, Evangelos


    To evaluate the role of biomass burning emissions, and in particular of residential wood heating, as a result of the economic recession in Greece, carbon monoxide (CO) atmospheric concentrations from five (5) stations of the National Air Pollution Monitoring Network in Athens, spanning the period 2000-2015, in conjunction with black carbon (BC) concentrations from the NOA (National Observatory of Athens) station at Thissio were analysed. The contribution of the different sources to the diurnal cycle of these two pollutants is clear, resulting to a morning peak, mainly due to traffic, and a late evening peak attributed both to fossil fuel (traffic plus central heating) and biomass combustion. Calculated morning and evening integrals of CO peaks, for the investigated period, show consistent seasonal modulations, characterised by low summer and high winter values. The summer and winter morning CO peak integrals demonstrate an almost constant decreasing trend of CO concentrations over time (by almost 50% since 2000), attributed to the renewal of passenger car fleet and to reduced anthropogenic activities during the last years. On the other hand, an increase of 23%-78% (depending on the monitoring site) in the winter evening integrals since 2012, provides evidence of the significant contribution of biomass combustion, which has prevailed over fossil fuel for domestic heating. CO emitted by wood burning was found to contribute almost 50% to the total CO emissions during night time (16:00-5:00), suggesting that emissions from biomass combustion have gained an increasing role in atmospheric pollution levels in Athens. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. The new open Flexible Emission Inventory for Greece and the Greater Athens Area (FEI-GREGAA): Account of pollutant sources and their importance from 2006 to 2012 (United States)

    Fameli, Kyriaki-Maria; Assimakopoulos, Vasiliki D.


    Photochemical and particulate pollution problems persist in Athens as they do in various European cities, despite measures taken. Although, for many cities, organized and updated pollutant emissions databases exist, as well as infrastructure for the support of policy implementation, this is not the case for Greece and Athens. So far abstract efforts to create inventories from temporal and spatial annual low resolution data have not lead to the creation of a useful database. The objective of this study was to construct an emission inventory in order to examine the emission trends in Greece and the Greater Athens Area for the period 2006-2012 on a spatial scale of 6 × 6 km2 and 2 × 2 km2, respectively and on a temporal scale of 1 h. Emissions were calculated from stationary combustion sources, transportation (road, navigation and aviation), agriculture and industry obtained from official national and European sources. Moreover, new emission factors were calculated for road transport and aviation. The final database named F.E.I. - GREGAA (Flexible Emission Inventory for GREece and the GAA) is open-structured so as to receive data updates, new pollutants, various emission scenarios and/or different emission factors and be transformed for any grid spacing. Its main purpose is to be used in applications with photochemical models to contribute to the investigation on the type of sources and activities that lead to the configuration of air quality. Results showed a decreasing trend in CO, NOx and VOCs-NMVOCs emissions and an increasing trend from 2011 onwards in PM10 emissions. Road transport and small combustion contribute most to CO emissions, road transport and navigation to NOx and small combustion and industries to PM10. The onset of the economic crisis can be seen from the reduction of emissions from industry and the increase of biomass burning for heating purposes.

  1. Accelerator based fusion reactor (United States)

    Liu, Keh-Fei; Chao, Alexander Wu


    A feasibility study of fusion reactors based on accelerators is carried out. We consider a novel scheme where a beam from the accelerator hits the target plasma on the resonance of the fusion reaction and establish characteristic criteria for a workable reactor. We consider the reactions d+t\\to n+α,d+{{}3}{{H}\\text{e}}\\to p+α , and p+{{}11}B\\to 3α in this study. The critical temperature of the plasma is determined from overcoming the stopping power of the beam with the fusion energy gain. The needed plasma lifetime is determined from the width of the resonance, the beam velocity and the plasma density. We estimate the critical beam flux by balancing the energy of fusion production against the plasma thermo-energy and the loss due to stopping power for the case of an inert plasma. The product of critical flux and plasma lifetime is independent of plasma density and has a weak dependence on temperature. Even though the critical temperatures for these reactions are lower than those for the thermonuclear reactors, the critical flux is in the range of {{10}22}-{{10}24}~\\text{c}{{\\text{m}}-2}~{{\\text{s}}-1} for the plasma density {ρt}={{10}15}~\\text{c}{{\\text{m}}-3} in the case of an inert plasma. Several approaches to control the growth of the two-stream instability are discussed. We have also considered several scenarios for practical implementation which will require further studies. Finally, we consider the case where the injected beam at the resonance energy maintains the plasma temperature and prolongs its lifetime to reach a steady state. The equations for power balance and particle number conservation are given for this case.

  2. Nuclear Reactor Safety; (USA)

    Energy Technology Data Exchange (ETDEWEB)

    Cason, D.L.; Hicks, S.C. (eds.)


    This publication announces on an monthly basis the current worldwide information available on all safety-related aspects of reactors, including: accident analysis, safety systems, radiation protection, decommissioning and dismantling, and security measures. This publication contains the abstracts of DOE reports, journal articles, conference papers, patents, theses, and monographs added to the Energy Science and Technology Database (EDB) during the past month. Also included are other US information obtained through acquisition programs or interagency agreements and international information obtained through the International Energy Agency's Technology Data Exchange, the International Atomic Energy Agency's International Nuclear Information System, or government-to-government agreements.

  3. Iris reactor development

    Energy Technology Data Exchange (ETDEWEB)

    Paramonov, D.V.; Carelli, M.D. [Westinghouse Electric Corp., Baltimore, MD (United States); Miller, K. [BNFL, Inc., (United Kingdom); Lombardi, C.V.; Ricotti, M.E. [Polytechnic of Milan, Polimi (Italy); Todreas, N.E. [Masachussets Institute of Technology, MIT (United States); Greenspan, E. [University of California at Berkeley, UCB (United States); Yamamoto, K. [JAPC Japan Atomic Power Co., Tokyo (Japan); Nagano, A. [Mitsubishi Heavy Industries Ltd., Tokyo (Japan); Ninokata, H. [Tokyo Institut of Technology, TIT (Japan); Robertson, J. [Westinghouse and bechtel (United States); Oriolo, F. [Pisa Univ. (Italy)


    The development progress of the IRIS (International Reactor Innovative and Secure) nuclear power system is presented. IRIS is currently being developed by an international consortium of industry, laboratory, university and utility establishments, led by Westinghouse. It is aimed at achieving the four major objectives of the Generation IV nuclear systems, i.e., proliferation resistance, enhanced safety, economic competitiveness and reduced waste. The project first year activities, which are summarized here, were focused on core neutronics, in-vessel configuration, steam generator and containment design, safety approach and economic performance. Details of these studies are provided in parallel papers in these proceedings. (author)


    Vernon, H.C.; Goett, J.J.


    A cover device is described for the fuel element receiving tube of a neutronic reactor of the heterogeneous, water cooled type wherein said tubes are arranged in a moderator with their longitudinal axes vertical. The cover is provided with means to support a rod-type fuel element from the bottom thereof and means to lock the cover in place, the latter being adapted for remote operation. This cover device is easily removable and seals the opening in the upper end of the fuel tube against leakage of coolant.

  5. Reactor coolant pump flywheel (United States)

    Finegan, John Raymond; Kreke, Francis Joseph; Casamassa, John Joseph


    A flywheel for a pump, and in particular a flywheel having a number of high density segments for use in a nuclear reactor coolant pump. The flywheel includes an inner member and an outer member. A number of high density segments are provided between the inner and outer members. The high density segments may be formed from a tungsten based alloy. A preselected gap is provided between each of the number of high density segments. The gap accommodates thermal expansion of each of the number of segments and resists the hoop stress effect/keystoning of the segments.


    Oppenheimer, E.D.; Weisberg, R.A.


    This patent relates to a barrier system for a sodium heavy water reactor capable of insuring absolute separation of the metal and water. Relatively cold D/sub 2/O moderator and reflector is contained in a calandria into which is immersed the fuel containing tubes. The fuel elements are cooled by the sodium which flows within the tubes and surrounds the fuel elements. The fuel containing tubes are surrounded by concentric barrier tubes forming annular spaces through which pass inert gases at substantially atmospheric pressure. Header rooms above and below the calandria are provided for supplying and withdrawing the sodium and inert gases in the calandria region. (AEC)

  7. Mass and chemical composition of size-segregated aerosols (PM1, PM2.5, PM10 over Athens, Greece: local versus regional sources

    Directory of Open Access Journals (Sweden)

    N. Mihalopoulos


    Full Text Available To identify the relative contribution of local versus regional sources of particulate matter (PM in the Greater Athens Area (GAA, simultaneous 24-h mass and chemical composition measurements of size segregated particulate matter (PM1, PM2.5 and PM10 were carried out from September 2005 to August 2006 at three locations: one urban (Goudi, Central Athens, "GOU", one suburban (Lykovrissi, Athens, "LYK" in the GAA and one at a regional background site (Finokalia, Crete, "FKL". The two stations in the GAA exceeded the EU-legislated PM10 limit values, both in terms of annual average (59.0 and 53.6 μg m−3 for Lykovrissi and Goudi, respectively and of 24-h value. High levels of PM2.5 and PM1 were also found at both locations (23.5 and 18.6 for Lykovrissi, while 29.4 and 20.2 μg m−3 for Goudi, respectively. Significant correlations were observed between the same PM fractions at both GAA sites indicating important spatial homogeneity within GAA. During the warm season (April to September, the PM1 ratio between GAA and FKL ranged from 1.1 to 1.3. On the other hand this ratio was significantly higher (1.6–1.7 during the cold season (October to March highlighting the role of long-range transport and local sources during the warm and cold seasons respectively. Regarding the coarse fraction no seasonal trend was observed for both GAA sites with their ratio (GAA site/FKL being higher than 2 indicating significant contribution from local sources such as soil and/or road dust. Chemical speciation data showed that on a yearly basis, ionic and crustal mass represent up to 67–70% of the gravimetrically determined mass for PM10 samples in the GAA and 67% for PM1 samples in LYK. The unidentified mass might be attributed to organic matter (OM and elemental carbon (EC, in agreement with the results reported by earlier studies in central Athens. At all sites, similar seasonal patterns were observed for nss-SO42−, a secondary compound, indicating significant

  8. Conference report on the 28th annual meeting of the European Musculo-Skeletal Oncology Society, 29 April–1 May 2015, Athens (United States)

    Leithner, Andreas; Andreou, Dimosthenis; Grimer, Robert; Ferrari, Stefano; Gosheger, Georg; Papagelopoulos, Panayiotis J; Bielack, Stefan S


    The 28th Annual Meeting of the European Musculo-Skeletal Oncology Society was organised in Athens by the local host Professor Papagelopoulos and his team. The main objective of the meeting was to focus on recent advances in the diagnosis and treatment of bone and soft tissue sarcomas. The interdisciplinary nature of the meeting was of great value—surgeons, oncologists, pathologists, radiologists, and basic researchers discussed new strategies in the war on sarcoma. This report will highlight the major findings of this successful meeting. PMID:26284114

  9. Summaries of invited lectures, oral and poster presentations given at the Thirteenth Hellenic Phytopathological Congress, Athens, Greece, 16–19 October 2006

    Directory of Open Access Journals (Sweden)


    Full Text Available The 13th National Phytopathological Congress, organized every two years by the Hellenic Phytopathological Society (HPS, was held in Athens, Greece, on October 16–19, 2006. The meeting was attended by more than 400 participants, and 49 oral presentations, 65 posters and 4 invited lectures were presented dealing with plant diseases caused by fungi, bacteria and viruses, non-parasitic disorders and disease control. In addition, one round table discussion was held on “The contribution of Phytopathology in the production of safe and high-quality agricultural products”. Abstracts of the invited lectures, oral presentations and posters of the congress are presented below.

  10. Fast Reactor Fuel Type and Reactor Safety Performance

    Energy Technology Data Exchange (ETDEWEB)

    R. Wigeland; J. Cahalan


    Fast Reactor Fuel Type and Reactor Safety Performance R. Wigeland , Idaho National Laboratory J. Cahalan, Argonne National Laboratory The sodium-cooled fast neutron reactor is currently being evaluated for the efficient transmutation of the highly-hazardous, long-lived, transuranic elements that are present in spent nuclear fuel. One of the fundamental choices that will be made is the selection of the fuel type for the fast reactor, whether oxide, metal, carbide, nitride, etc. It is likely that a decision on the fuel type will need to be made before many of the related technologies and facilities can be selected, from fuel fabrication to spent fuel reprocessing. A decision on fuel type should consider all impacts on the fast reactor system, including safety. Past work has demonstrated that the choice of fuel type may have a significant impact on the severity of consequences arising from accidents, especially for severe accidents of low probability. In this paper, the response of sodium-cooled fast reactors is discussed for both oxide and metal fuel types, highlighting the similarities and differences in reactor response and accident consequences. Any fast reactor facility must be designed to be able to successfully prevent, mitigate, or accommodate all consequences of potential events, including accidents. This is typically accomplished by using multiple barriers to the release of radiation, including the cladding on the fuel, the intact primary cooling system, and most visibly the reactor containment building. More recently, this has also included the use of ‘inherent safety’ concepts to reduce or eliminate the potential for serious damage in some cases. Past experience with oxide and metal fuel has demonstrated that both fuel types are suitable for use as fuel in a sodium-cooled fast reactor. However, safety analyses for these two fuel types have also shown that there can be substantial differences in accident consequences due to the neutronic and

  11. Reactor Physics Analysis Models for a CANDU Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hang Bok


    Canada deuterium uranium (CANDU) reactor physics analysis is typically performed in three steps. At first, macroscopic cross-sections of the reference lattice is produced by modeling the reference fuel channel. Secondly macroscopic cross-sections of reactivity devices in the reactor are generated. The macroscopic cross-sections of a reactivity device are calculated as incremental cross-sections by subtracting macroscopic cross-sections of a three-dimensional lattice without reactivity device from those of a three-dimensional lattice with a reactivity device. Using the macroscopic cross-sections of the reference lattice and incremental cross-sections of the reactivity devices, reactor physics calculations are performed. This report summarizes input data of typical CANDU reactor physics codes, which can be utilized for the future CANDU reactor physics analysis.

  12. Decommissioning of commercial reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yui, Kohei [Japan Atomic Power Co., Tokyo (Japan)


    In the case of nuclear reactors, the diversion is often difficult as they are highly purposive, the disassembling is not easy as they are robust, and attention is required to handle the equipment containing radioactive substances. Decommissioning is defined as all the measures taken from the state that facilities become unused to the state of becoming green field. In Japan, already 40 years have elapsed since the effort for nuclear power was begun, and in this paper, the present state and future subjects of the decommissioning of nuclear power stations are summarized at the opportunity that the stop of commercial operation of Tokai Nuclear Power Station was decided recently. In the Tokai Nuclear Power Station, 166 MWe graphite-moderated, carbon dioxide-cooled reactor called improved Calder Hall type is installed, which started the operation in 1966. The circumstances of the decision to stop its operation are explained. The basic policy of the decommissioning of commercial nuclear power stations has been already published by the Advisory Committee for Energy. The state of the decommissioning in various foreign countries is reported. In Japan, the state of green field was realized in 1996 in the decommissioning of the JPDR in Japan Atomic Energy Research institute, and the decommissioning of the atomic powered ship ``Mutsu`` was completed. (K.I.)

  13. Solvent refined coal reactor quench system (United States)

    Thorogood, R.M.


    There is described an improved SRC reactor quench system using a condensed product which is recycled to the reactor and provides cooling by evaporation. In the process, the second and subsequent reactors of a series of reactors are cooled by the addition of a light oil fraction which provides cooling by evaporation in the reactor. The vaporized quench liquid is recondensed from the reactor outlet vapor stream. 1 fig.

  14. Brookhaven leak reactor to close

    CERN Multimedia

    MacIlwain, C


    The DOE has announced that the High Flux Beam Reactor at Brookhaven is to close for good. Though the news was not unexpected researchers were angry the decision had been taken before the review to assess the impact of reopening the reactor had been concluded (1 page).

  15. Rotary reactor and use thereof

    NARCIS (Netherlands)

    Bakker Wridzer, J.W.; Kapteijn, F.; Moulijn, J.A.


    The invention relates to a rotary reactor consisting of a number of tubular reaction compartments (A), each provided with a first end and a second end, a ceramic first reactor end plate (B) in which said first ends are received, and a second end plate (B) in which said second ends are received,

  16. Radiation Shielding for Fusion Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Santoro, R.T.


    Radiation shielding requirements for fusion reactors present different problems than those for fission reactors and accelerators. Fusion devices, particularly tokamak reactors, are complicated by geometry constraints that complicate disposition of fully effective shielding. This paper reviews some of these shielding issues and suggested solutions for optimizing the machine and biological shielding. Radiation transport calculations are essential for predicting and confirming the nuclear performance of the reactor and, as such, must be an essential part of the reactor design process. Development and optimization of reactor components from the first wall and primary shielding to the penetrations and containment shielding must be carried out in a sensible progression. Initial results from one-dimensional transport calculations are used for scoping studies and are followed by detailed two- and three-dimensional analyses to effectively characterize the overall radiation environment. These detail model calculations are essential for accounting for the radiation leakage through ports and other penetrations in the bulk shield. Careful analysis of component activation and radiation damage is cardinal for defining remote handling requirements, in-situ replacement of components, and personnel access at specific locations inside the reactor containment vessel. Radiation shielding requirements for fusion reactors present different problems than those for fission reactors and accelerators. Fusion devices, particularly tokamak reactors, are complicated by geometry constraints that complicate disposition of fully effective shielding. This paper reviews some of these shielding issues and suggested solutions for optimizing the machine and biological shielding. Radiation transport calculations are essential for predicting and confirming the nuclear performance of the reactor and, as such, must be an essential part of the reactor design process. Development and optimization of reactor

  17. Origins of n-alkanes, carbonyl compounds and molecular biomarkers in atmospheric fine and coarse particles of Athens, Greece. (United States)

    Andreou, G; Rapsomanikis, S


    The abundance and origin of aliphatic hydrocarbons, carbonyl compounds and molecular biomarkers found in the aliphatic fraction of PM(10-2.5) and PM(2.5) in the centre of Athens Greece are discussed in an attempt to reveal seasonal air pollution characteristics of the conurbation. Each extract was fractionated into individual compound classes and was analyzed using gas chromatography coupled to mass spectrometry. Normal alkanes, ranging from C(14) to C(35), were abundant in PM(10-2.5) and PM(2.5) samples during both sampling campaigns. The daily concentration of total n-alkanes was up to 438 ng m(-3) for PM(10-2.5) and up to 511 ng m(-3) for PM(2.5). Additionally, gaseous concentrations of n-alkanes were calculated, revealing that the relative proportions between gaseous and particle phases of individual compounds may differ significantly between summer and late winter. Normal alkanals and alkan-2-ones were only detected in the fine fraction of particulate matter and their concentrations were much lower than the n-alkane concentrations. Several geochemical parameters were used to qualitatively reconcile the sources of organic aerosol. The carbon preference index (CPI) of the coarse particles in August had the highest value, while in March the leaf wax contribution decreased significantly and the CPI value was very close to unity for both sites. Maximum concentrations of carbonyl compounds were reported in the range of C(15)-C(20), demonstrating that they were formed from anthropogenic activity or from atmospheric oxidative processes. 6, 10, 14-trimethylpentadecan-2-one, a marker of biogenic input, was also detected in our samples. Molecular biomarker compounds confirmed that ca. 60% of the aliphatic fraction on the sampled atmospheric particles originated from petroleum and not from any contemporary biogenic sources. Pristane and phytane were detected in the fine fraction with their presence indicating sources of fossil fuel in the range of C(16)-C(20). At all

  18. Analysis of long-term variation of the annual number of warmer and colder days using Mahalanobis distance metrics - A case study for Athens (United States)

    Matcharashvili, Teimuraz; Zhukova, Natalia; Chelidze, Tamaz; Founda, Dimitra; Gerasopoulos, Evangelos


    According to contemporary observations and analyses an increase in the number of warm days is evident, associated to global warming and the air temperature increase. At the same time, many questions regarding the variation of the yearly number of warm (and cold) day anomalies remain unanswered. In the present work, we used a 99-year long time series of daily maximum air temperatures from the historical, climatic station in Athens, Greece, to produce data sets of sequences of the yearly number of days with anomalies significantly larger (warmer)/lower (colder), with respect to the long-term mean anomalies for the same days. The main goal was to introduce and test the appropriateness of our approach, in assessing changes of the local climate system during last century. This approach is based on the Mahalanobis distance metrics of the variability of the annual number of warmer and colder days derived from the long period data sets of the daily max air temperatures. We show that in Athens the features of the local climate system, assessed by the variability of warmer and colder days, have significantly changed during the observation period. In particular, essential changes are revealed in the temporal correlations of the variability of the annual number of warmer and colder days, during different sub-periods in the past century. Greater changes are found in the last two to three decades, though similar or even stronger changes have also occurred in the past.

  19. NELIOTA: ESA's new NEO lunar impact monitoring project with the 1.2m telescope at the National Observatory of Athens (United States)

    Bonanos, A. Z.; Xilouris, M.; Boumis, P.; Bellas-Velidis, I.; Maroussis, A.; Dapergolas, A.; Fytsilis, A.; Charmandaris, V.; Tsiganis, K.; Tsinganos, K.


    NELIOTA is a new ESA activity launched at the National Observatory of Athens in February 2015 aiming to determine the distribution and frequency of small near-earth objects (NEOs) via lunar monitoring. The project involves upgrading the 1.2m Kryoneri telescope of the National Observatory of Athens, building a two fast-frame camera instrument, and developing a software system, which will control the telescope and the cameras, process the images and automatically detect NEO impacts. NELIOTA will provide a web-based user interface, where the impact events will be reported and made available to the scientific community and the general public. The objective of this 3.5 year activity is to design, develop and implement a highly automated lunar monitoring system, which will conduct an observing campaign for 2 years in search of NEO impact flashes on the Moon. The impact events will be verified, characterised and reported. The 1.2m telescope will be capable of detecting flashes much fainter than current, small-aperture, lunar monitoring telescopes. NELIOTA is therefore expected to characterise the frequency and distribution of NEOs weighing as little as a few grams.

  20. New early Pliocene owls from Langebaanweg, South Africa, with first evidence of Athene south of the Sahara and a new species of Tyto

    Directory of Open Access Journals (Sweden)

    Marco Pavia


    Full Text Available The fossiliferous Upper Varswater Formation at Langebaanweg (South Africa produced remains of at least five species of owls (Strigiformes. Tyto richae sp. nov. is the first palaeospecies of Tytonidae described from an African fossil site, though indeterminate remains referable to the genus Tyto are known from the Middle Miocene of Morocco, the early Pliocene of Ethiopia, and the Pliocene of Tanzania. Athene inexpectata sp. nov. is not only the earliest documented fossil evidence for the genus worldwide, but also the first record of a species of Athene in Africa south of the Sahara. Proportions of its hind limb indicate that At. inexpectata sp. nov. probably has been as terrestrial as its modern relative At. cunicularia. A few additional remains represent the earliest fossil evidence for the genera Asio and Bubo on the African continent, though the poor preservation of these bones prevents more detailed identifications. A distal tibiotarsus of a small owl about the size of At. inexpectata sp. nov. indicates the presence of a fifth, as yet indeterminate, species of owl at Langebaanweg. Biogeographical and palaeoecological implications of this assemblage of owls are discussed.

  1. A comprehensive approach for the simulation of the Urban Heat Island effect with the WRF/SLUCM modeling system: The case of Athens (Greece) (United States)

    Giannaros, Christos; Nenes, Athanasios; Giannaros, Theodore M.; Kourtidis, Konstantinos; Melas, Dimitrios


    This study presents a comprehensive modeling approach for simulating the spatiotemporal distribution of urban air temperatures with a modeling system that includes the Weather Research and Forecasting (WRF) model and the Single-Layer Urban Canopy Model (SLUCM) with a modified treatment of the impervious surface temperature. The model was applied to simulate a 3-day summer heat wave event over the city of Athens, Greece. The simulation, using default SLUCM parameters, is capable of capturing the observed diurnal variation of urban temperatures and the Urban Heat Island (UHI) in the greater Athens Area (GAA), albeit with systematic biases that are prominent during nighttime hours. These biases are particularly evident over low-intensity residential areas, and they are associated with the surface and urban canopy properties representing the urban environment. A series of sensitivity simulations unravels the importance of the sub-grid urban fraction parameter, surface albedo, and street canyon geometry in the overall causation and development of the UHI effect. The sensitivities are then used to determine optimal values of the street canyon geometry, which reproduces the observed temperatures throughout the simulation domain. The optimal parameters, apart from considerably improving model performance (reductions in mean temperature bias from 0.30 °C to 1.58 °C), are also consistent with actual city building characteristics - which gives confidence that the model set-up is robust, and can be used to study the UHI in the GAA in the anticipated warmer conditions in the future.

  2. Neutrino Experiments at Reactors (United States)

    Reines, F.; Gurr, H. S.; Jenkins, T. L.; Munsee, J. H.


    A description is given of the electron-antineutrino program using a large fission reactor. A search has been made for a neutral weak interaction via the reaction (electron antineutrino + d .> p + n + electron antineutrino), the reaction (electron antineutrino + d .> n + n + e{sup +}) has now been detected, and an effort is underway to observe the elastic scattering reaction (electron antineutrino + e{sup -} .> electron antineutrino + e{sup -}) as well as to measure more precisely the reaction (electron antineutrino + p .> n + e{sup+}). The upper limit on the elastic scattering reaction which we have obtained with our large composite NaI, plastic, liquid scintillation detector is now about 50 times the predicted value.

  3. Licensed reactor nuclear safety criteria applicable to DOE reactors

    Energy Technology Data Exchange (ETDEWEB)


    This document is a compilation and source list of nuclear safety criteria that the Nuclear Regulatory Commission (NRC) applies to licensed reactors; it can be used by DOE and DOE contractors to identify NRC criteria to be evaluated for application to the DOE reactors under their cognizance. The criteria listed are those that are applied to the areas of nuclear safety addressed in the safety analysis report of a licensed reactor. They are derived from federal regulations, USNRC regulatory guides, Standard Review Plan (SRP) branch technical positions and appendices, and industry codes and standards.

  4. Advanced fusion reactor

    Energy Technology Data Exchange (ETDEWEB)

    Tomita, Yukihiro [National Inst. for Fusion Science, Toki, Gifu (Japan)


    The main subjects on fusion research are now on D-T fueled fusion, mainly due to its high fusion reaction rate. However, many issues are still remained on the wall loading by the 14 MeV neutrons. In the case of D-D fueled fusion, the neutron wall loading is still remained, though the technology related to tritium breeding is not needed. The p-{sup 6}Li and p-{sup 11}B fueled fusions are not estimated to be the next generation candidate until the innovated plasma confinement technologies come in useful to achieve the high performance plasma parameters. The fusion reactor of D-{sup 3}He fuels has merits on the smaller neutron wall loading and tritium handling. However, there are difficulties on achieving the high temperature plasma more than 100 keV. Furthermore the high beta plasma is needed to decrease synchrotron radiation loss. In addition, the efficiency of the direct energy conversion from protons coming out from fusion reaction is one of the key parameters in keeping overall power balance. Therefore, open magnetic filed lines should surround the plasma column. In this paper, we outlined the design of the commercial base reactor (ARTEMIS) of 1 GW electric output power configured by D-{sup 3}He fueled FRC (Field Reversed Configuration). The ARTEMIS needs 64 kg of {sup 3}He per a year. On the other hand, 1 million tons of {sup 3}He is estimated to be in the moon. The {sup 3}He of about 10{sup 23} kg are to exist in gaseous planets such as Jupiter and Saturn. (Y. Tanaka)

  5. Chemical characterization of the inorganic fraction of aerosols and mechanisms of the neutralization of atmospheric acidity in Athens, Greece

    Directory of Open Access Journals (Sweden)

    E. T. Karageorgos


    Full Text Available The PM10 mass concentration levels and inorganic chemical composition were determined on 12-h resolution sampling during August 2003 and March 2004, in the centre of Athens, Greece. The August 2003 campaign mean PM10 mass concentration, obtained by Beta Attenuation at 5 m above ground in Athinas Street, was 56 μg m−3 while the corresponding value for March 2004 was 92 μg m−3. In both campaigns the E.U. imposed daily limit of 50 μg m−3 was exceeded on several days. During the March campaign, in Athinas Street, additionally obtained DSFU-PM10 (PM10-2.5+PM2.5 gravimetric mass concentrations (mean: 121 μg m−3 in the "breathing zone", at 1.5 m above ground were significantly higher compared to the respective mean PM10 mass concentrations obtained by the same method at 25 m above ground, in a second site (AEDA; mean: 86 μg m−3 also in the centre of the city. The above findings suggest that, for a realistic estimation of the exposure of citizens to particulate matter, PM10 sampling in the "breathing zone" (1.5–3 m above ground is necessary. Such data are presented for the first time for the centre of Athens. In both campaigns, calcium was found to be the predominant component of the coarse fraction while crust-related aluminosilicates and iron were the other major components. The above elements constitute the most important components of the fine fraction, together with the predominant sulphur. All toxic metals were found in concentrations below the established air quality limits, and most of them in lower concentrations compared to older studies. Lead in particular, appeared mostly in the fine fraction and in very low concentrations compared to studies dating more than a decade back. The predominant ions of the coarse fraction have been found to be Ca2+, NO3, Na

  6. Heating device for nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Shiratori, Yoshitake; Ijima, Takashi; Katano, Yoshiaki; Saito, Masaki


    The present invention provides a control system of a heating device which elevates the temperature of a reactor from a normal temperature to an operation temperature by using a nuclear heating. Namely, the device of the present invention comprises (1) means for detecting reactor temperature, (2) means for detecting reactor power, (3) means for memorizing the corresponding relation of each value of the means (1) and means (2) as standard data when temperature is elevated at a predetermined temperature elevation rate, (4) means for calculating the power corresponding to the current temperature based on the standard data upon elevation of the reactor temperature, and (5) means for controlling the progress or retraction of the power control material of the reactor core based on the power calculated by the means (4). With such a constitution, since the current reactor power elevation rate corresponding to the coolants is controlled based on the standard data upon actual start-up of the reactor, the control for the temperature of coolants can be facilitated. (I.S.)

  7. Random processes in nuclear reactors

    CERN Document Server

    Williams, M M R


    Random Processes in Nuclear Reactors describes the problems that a nuclear engineer may meet which involve random fluctuations and sets out in detail how they may be interpreted in terms of various models of the reactor system. Chapters set out to discuss topics on the origins of random processes and sources; the general technique to zero-power problems and bring out the basic effect of fission, and fluctuations in the lifetime of neutrons, on the measured response; the interpretation of power reactor noise; and associated problems connected with mechanical, hydraulic and thermal noise sources

  8. Nuclear reactor downcomer flow deflector (United States)

    Gilmore, Charles B [Greensburg, PA; Altman, David A [Pittsburgh, PA; Singleton, Norman R [Murrysville, PA


    A nuclear reactor having a coolant flow deflector secured to a reactor core barrel in line with a coolant inlet nozzle. The flow deflector redirects incoming coolant down an annulus between the core barrel and the reactor vessel. The deflector has a main body with a front side facing the fluid inlet nozzle and a rear side facing the core barrel. The rear side of the main body has at least one protrusion secured to the core barrel so that a gap exists between the rear side of the main body adjacent the protrusion and the core barrel. Preferably, the protrusion is a relief that circumscribes the rear side of the main body.

  9. Reactor neutrons in nuclear astrophysics (United States)

    Reifarth, René; Glorius, Jan; Göbel, Kathrin; Heftrich, Tanja; Jentschel, Michael; Jurado, Beatriz; Käppeler, Franz; Köster, Ulli; Langer, Christoph; Litvinov, Yuri A.; Weigand, Mario


    The huge neutron fluxes offer the possibility to use research reactors to produce isotopes of interest, which can be investigated afterwards. An example is the half-lives of long-lived isotopes like 129I. A direct usage of reactor neutrons in the astrophysical energy regime is only possible, if the corresponding ions are not at rest in the laboratory frame. The combination of an ion storage ring with a reactor and a neutron guide could open the path to direct measurements of neutron-induced cross sections on short-lived radioactive isotopes in the astrophysically interesting energy regime.

  10. Safety of VVER-440 reactors

    CERN Document Server

    Slugen, Vladimir


    Safety of VVER-440 Reactors endeavours to promote an increase in the safety of VVER-440 nuclear reactors via the improvement of fission products limitation systems and the implementation of special non-destructive spectroscopic methods for materials testing. All theoretical and experimental studies performed the by author over the last 25 years have been undertaken with the aim of improving VVER-440 defence in depth, which is one of the most important principle for ensuring safety in nuclear power plants. Safety of VVER-440 Reactors is focused on the barrier system through which the safety pri

  11. Fuel Fabrication and Nuclear Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Karpius, Peter Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    The uranium from the enrichment plant is still in the form of UF6. UF6 is not suitable for use in a reactor due to its highly corrosive chemistry as well as its phase diagram. UF6 is converted into UO2 fuel pellets, which are in turn placed in fuel rods and assemblies. Reactor designs are variable in moderators, coolants, fuel, performance etc.The dream of energy ‘too-cheap to meter’ is no more, and now the nuclear power industry is pushing ahead with advanced reactor designs.

  12. The Olympieion at Athens

    Directory of Open Access Journals (Sweden)

    R. E. Wycherley


    Full Text Available The phases of construction of the temple (Peisistratid, Seleucid, Hadrianic and its state in between them can be partly reconstructed from the fragmentary literary and archeological evidence; the other Athenian cults of Zeus are also surveyed.

  13. Nuclear reactor PBMR and cogeneration; Reactor nuclear PBMR y cogeneracion

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez S, J. R.; Alonso V, G., E-mail: [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)


    In recent years the nuclear reactor designs for the electricity generation have increased their costs, so that at the moment costs are managed of around the 5000 US D for installed kw, reason for which a big nuclear plant requires of investments of the order of billions of dollars, the designed reactors as modular of low power seek to lighten the initial investment of a big reactor dividing the power in parts and dividing in modules the components to lower the production costs, this way it can begin to build a module and finished this to build other, differing the long term investment, getting less risk therefore in the investment. On the other hand the reactors of low power can be very useful in regions where is difficult to have access to the electric net being able to take advantage of the thermal energy of the reactor to feed other processes like the water desalination or the vapor generation for the processes industry like the petrochemical, or even more the possible hydrogen production to be used as fuel. In this work the possibility to generate vapor of high quality for the petrochemical industry is described using a spheres bed reactor of high temperature. (Author)

  14. FASTER test reactor preconceptual design report summary

    Energy Technology Data Exchange (ETDEWEB)

    Grandy, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Belch, H. [Argonne National Lab. (ANL), Argonne, IL (United States); Brunett, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Heidet, F. [Argonne National Lab. (ANL), Argonne, IL (United States); Hill, R. [Argonne National Lab. (ANL), Argonne, IL (United States); Hoffman, E. [Argonne National Lab. (ANL), Argonne, IL (United States); Jin, E. [Argonne National Lab. (ANL), Argonne, IL (United States); Mohamed, W. [Argonne National Lab. (ANL), Argonne, IL (United States); Moisseytsev, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Passerini, S. [Argonne National Lab. (ANL), Argonne, IL (United States); Sienicki, J. [Argonne National Lab. (ANL), Argonne, IL (United States); Sumner, T. [Argonne National Lab. (ANL), Argonne, IL (United States); Vilim, R. [Argonne National Lab. (ANL), Argonne, IL (United States); Hayes, Steven [Argonne National Lab. (ANL), Argonne, IL (United States)


    The FASTER reactor plant is a sodium-cooled fast spectrum test reactor that provides high levels of fast and thermal neutron flux for scientific research and development. The 120MWe FASTER reactor plant has a superheated steam power conversion system which provides electrical power to a local grid allowing for recovery of operating costs for the reactor plant.

  15. FASTER Test Reactor Preconceptual Design Report

    Energy Technology Data Exchange (ETDEWEB)

    Grandy, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Belch, H. [Argonne National Lab. (ANL), Argonne, IL (United States); Brunett, A. J. [Argonne National Lab. (ANL), Argonne, IL (United States); Heidet, F. [Argonne National Lab. (ANL), Argonne, IL (United States); Hill, R. [Argonne National Lab. (ANL), Argonne, IL (United States); Hoffman, E. [Argonne National Lab. (ANL), Argonne, IL (United States); Jin, E. [Argonne National Lab. (ANL), Argonne, IL (United States); Mohamed, W. [Argonne National Lab. (ANL), Argonne, IL (United States); Moisseytsev, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Passerini, S. [Argonne National Lab. (ANL), Argonne, IL (United States); Sienicki, J. [Argonne National Lab. (ANL), Argonne, IL (United States); Sumner, T. [Argonne National Lab. (ANL), Argonne, IL (United States); Vilim, R. [Argonne National Lab. (ANL), Argonne, IL (United States); Hayes, S. [Argonne National Lab. (ANL), Argonne, IL (United States)


    The FASTER test reactor plant is a sodium-cooled fast spectrum test reactor that provides high levels of fast and thermal neutron flux for scientific research and development. The 120MWe FASTER reactor plant has a superheated steam power conversion system which provides electrical power to a local grid allowing for recovery of operating costs for the reactor plant.


    Directory of Open Access Journals (Sweden)

    Vyacheslav K. Mayevski


    Full Text Available This paper describes a mathematical model of an industrial chemical reactor for production of synthetic rubber. During reactor operation the model parameters vary considerably. To create a control algorithm performed transformation of mathematical model of the reactor in order to obtain a dependency that can be used to determine the model parameters are changing during reactor operation.

  17. Rune Frederiksen, Elizabeth R. Gebhard & Alexander Sokolicek (eds., The Architecture of the Ancient Greek Theatre, Monographs of the Danish Institute, Volume 17 (Aarhus: Aarhus University Press and The Danish Institute at Athens, 2015

    Directory of Open Access Journals (Sweden)

    William C. Miller


    Full Text Available A review of the book: Rune Frederiksen, Elizabeth R. Gebhard & Alexander Sokolicek (eds., The Architecture of the Ancient Greek Theatre, Monographs of the Danish Institute, Volume 17 (Aarhus: Aarhus University Press and The Danish Institute at Athens, 2015

  18. Reactor operation environmental information document

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, L.R.; Hayes, D.W.; Hunter, C.H.; Marter, W.L.; Moyer, R.A.


    This volume is a reactor operation environmental information document for the Savannah River Plant. Topics include meteorology, surface hydrology, transport, environmental impacts, and radiation effects. 48 figs., 56 tabs. (KD)

  19. Reactor containment research and development

    Energy Technology Data Exchange (ETDEWEB)

    Weil, N. A.


    An outline is given of containment concepts, sources and release rates of energy, responses of containment structures, effects of projectiles, and leakage rates of radioisotopes, with particular regard to major reactor accidents. (T.F.H.)

  20. Actinide transmutation in nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Ganev, I.K.; Lopatkin, A.V.; Naumov, V.V.; Tocheny, L.V.


    Of some interest is the comparison between the actinide nuclide burning up (fission) rates such as americium 241, americium 242, curium 244, and neptunium 237, in the reactors with fast or thermal neutron spectra.

  1. Advanced Carbothermal Electric Reactor Project (United States)

    National Aeronautics and Space Administration — ORBITEC proposes to develop the Advanced Carbothermal Electric (ACE) reactor to efficiently extract oxygen from lunar regolith. Unlike state-of-the-art carbothermal...

  2. Combustion synthesis continuous flow reactor

    Energy Technology Data Exchange (ETDEWEB)

    Maupin, G.D.; Chick, L.A.; Kurosky, R.P.


    The present invention is a reactor for combustion synthesis of inorganic powders. The reactor includes a reaction vessel having a length and a first end and a second end. The reaction vessel further has a solution inlet and a carrier gas inlet. The reactor further has a heater for heating both the solution and the carrier gas. In a preferred embodiment, the reaction vessel is heated and the solution is in contact with the heated reaction vessel. It is further preferred that the reaction vessel be cylindrical and that the carrier gas is introduced tangentially into the reaction vessel so that the solution flows helically along the interior wall of the reaction vessel. As the solution evaporates and combustion produces inorganic material powder, the carrier gas entrains the powder and carries it out of the reactor. 10 figs.

  3. Combustion synthesis continuous flow reactor

    Energy Technology Data Exchange (ETDEWEB)

    Maupin, Gary D. (Richland, WA); Chick, Lawrence A. (West Richland, WA); Kurosky, Randal P. (Maple Valley, WA)


    The present invention is a reactor for combustion synthesis of inorganic powders. The reactor includes a reaction vessel having a length and a first end and a second end. The reaction vessel further has a solution inlet and a carrier gas inlet. The reactor further has a heater for heating both the solution and the carrier gas. In a preferred embodiment, the reaction vessel is heated and the solution is in contact with the heated reaction vessel. It is further preferred that the reaction vessel be cylindrical and that the carrier gas is introduced tangentially into the reaction vessel so that the solution flows helically along the interior wall of the reaction vessel. As the solution evaporates and combustion produces inorganic material powder, the carrier gas entrains the powder and carries it out of the reactor.

  4. Advanced Carbothermal Electric Reactor Project (United States)

    National Aeronautics and Space Administration — The overall objective of the Phase 1 effort was to demonstrate the technical feasibility of the Advanced Carbothermal Electric (ACE) Reactor concept. Unlike...

  5. Advanced Catalytic Hydrogenation Retrofit Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Reinaldo M. Machado


    Industrial hydrogenation is often performed using a slurry catalyst in large stirred-tank reactors. These systems are inherently problematic in a number of areas, including industrial hygiene, process safety, environmental contamination, waste production, process operability and productivity. This program proposed the development of a practical replacement for the slurry catalysts using a novel fixed-bed monolith catalyst reactor, which could be retrofitted onto an existing stirred-tank reactor and would mitigate many of the minitations and problems associated with slurry catalysts. The full retrofit monolith system, consisting of a recirculation pump, gas/liquid ejector and monolith catalyst, is described as a monolith loop reactor or MLR. The MLR technology can reduce waste and increase raw material efficiency, which reduces the overall energy required to produce specialty and fine chemicals.

  6. Engineering reactors for catalytic reactions

    Indian Academy of Sciences (India)

    Chemical Engineering and Process Development Division, CSIR - National Chemical Laboratory,. Pune 411 008, India ... Abstract. Catalytic reactions are ubiquitous in chemical and allied industries. ... strategies and recent advances in process intensification/ multifunctional reactors are discussed to illustrate the approach.

  7. Jules Horowitz Reactor, basic design

    Energy Technology Data Exchange (ETDEWEB)

    Bergamaschi, Y.; Bouilloux, Y.; Chantoin, P.; Guigon, B.; Bravo, X.; Germain, C.; Rommens, M.; Tremodeux, P


    Since the shutdown of the SILOE reactor in 1997, the OSIRIS reactor has ensured the needs regarding technological irradiation at CEA including those of its industrial partners and customers. The Jules Horowitz Reactor will replace it. It has the ambition to provide the necessary nuclear data and maintain a fission research capacity in Europe after 2010. This capacity should be service-oriented. It will be established in Cadarache. The Jules Horowitz reactor will also: - represent a significant step in term of performances and experimental capabilities, - be designed with a high flexibility, in order to satisfy the current demand from European industry, research and be able to accommodate future requirements, - reach a high level of safety, according to the best current practice. This paper will present the main functionalities and the design options resulting from the 'preliminary design' studies. (authors)

  8. Solid State Reactor Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Mays, G.T.


    The Solid State Reactor (SSR) is an advanced reactor concept designed to take advantage of Oak Ridge National Laboratory's (ORNL's) recently developed graphite foam that has enhanced heat transfer characteristics and excellent high-temperature mechanical properties, to provide an inherently safe, self-regulated, source of heat for power and other potential applications. This work was funded by the U.S. Department of Energy's Nuclear Energy Research Initiative (NERI) program (Project No. 99-064) from August 1999 through September 30, 2002. The initial concept of utilizing the graphite foam as a basis for developing an advanced reactor concept envisioned that a suite of reactor configurations and power levels could be developed for several different applications. The initial focus was looking at the reactor as a heat source that was scalable, independent of any heat removal/power conversion process. These applications might include conventional power generation, isotope production and destruction (actinides), and hydrogen production. Having conducted the initial research on the graphite foam and having performed the scoping parametric analyses from neutronics and thermal-hydraulic perspectives, it was necessary to focus on a particular application that would (1) demonstrate the viability of the overall concept and (2) require a reasonably structured design analysis process that would synthesize those important parameters that influence the concept the most as part of a feasible, working reactor system. Thus, the application targeted for this concept was supplying power for remote/harsh environments and a design that was easily deployable, simplistic from an operational standpoint, and utilized the new graphite foam. Specifically, a 500-kW(t) reactor concept was pursued that is naturally load following, inherently safe, optimized via neutronic studies to achieve near-zero reactivity change with burnup, and proliferation resistant. These four major areas

  9. Microchannel Reactors for ISRU Applications (United States)

    Carranza, Susana; Makel, Darby B.; Blizman, Brandon; Ward, Benjamin J.


    Affordable planning and execution of prolonged manned space missions depend upon the utilization of local resources and the waste products which are formed in manned spacecraft and surface bases. Successful in-situ resources utilization (ISRU) will require component technologies which provide optimal size, weight, volume, and power efficiency. Microchannel reactors enable the efficient chemical processing of in situ resources. The reactors can be designed for the processes that generate the most benefit for each mission. For instance, propellants (methane) can be produced from carbon dioxide from the Mars atmosphere using the Sabatier reaction and ethylene can be produced from the partial oxidation of methane. A system that synthesizes ethylene could be the precursor for systems to synthesize ethanol and polyethylene. Ethanol can be used as a nutrient for Astrobiology experiments, as well as the production of nutrients for human crew (e.g. sugars). Polyethylene can be used in the construction of habitats, tools, and replacement parts. This paper will present recent developments in miniature chemical reactors using advanced Micro Electro Mechanical Systems (MEMS) and microchannel technology to support ISRU of Mars and lunar missions. Among other applications, the technology has been demonstrated for the Sabatier process and for the partial oxidation of methane. Microchannel reactors were developed based on ceramic substrates as well as metal substrates. In both types of reactors, multiple layers coated with catalytic material are bonded, forming a monolithic structure. Such reactors are readily scalable with the incorporation of extra layers. In addition, this reactor structure minimizes pressure drop and catalyst settling, which are common problems in conventional packed bed reactors.

  10. Reactor antineutrinos and nuclear physics

    Energy Technology Data Exchange (ETDEWEB)

    Balantekin, A.B. [University of Wisconsin, Department of Physics, Madison, WI (United States)


    Short-baseline reactor neutrino experiments successfully measured the neutrino parameters they set out to measure, but they also identified a shape distortion in the 5-7 MeV range as well as a reduction from the predicted value of the flux. Nuclear physics input into the calculations of reactor antineutrino spectra needs to be better refined if this anomaly is to be interpreted as due to sterile neutrino states. (orig.)

  11. Design and baseline findings of a large-scale rapid response to an HIV outbreak in people who inject drugs in Athens, Greece: the ARISTOTLE programme. (United States)

    Hatzakis, Angelos; Sypsa, Vana; Paraskevis, Dimitrios; Nikolopoulos, Georgios; Tsiara, Chrissa; Micha, Katerina; Panopoulos, Anastasios; Malliori, Meni; Psichogiou, Mina; Pharris, Anastasia; Wiessing, Lucas; van de Laar, Marita; Donoghoe, Martin; Heckathorn, Douglas D; Friedman, Samuel R; Des Jarlais, Don C


    To (i) describe an intervention implemented in response to the HIV-1 outbreak among people who inject drugs (PWIDs) in Greece (ARISTOTLE programme), (ii) assess its success in identifying and testing this population and (iii) describe socio-demographic characteristics, risk behaviours and access to treatment/prevention, estimate HIV prevalence and identify risk factors, as assessed at the first participation of PWIDs. A 'seek, test, treat, retain' intervention employing five rounds of respondent-driven sampling. Athens, Greece (2012-13). A total of 3320 individuals who had injected drugs in the past 12 months. ARISTOTLE is an intervention that involves reaching out to high-risk, hard-to-reach PWIDs ('seek'), engaging them in HIV testing and providing information and materials to prevent HIV ('test') and initiating and maintaining anti-retroviral and opioid substitution treatment for those testing positive ('treat' and 'retain'). Blood samples were collected for HIV testing and personal interviews were conducted. ARISTOTLE recruited 3320 PWIDs during the course of 13.5 months. More than half (54%) participated in multiple rounds, resulting in 7113 visits. HIV prevalence was 15.1%. At their first contact with the programme, 12.5% were on opioid substitution treatment programmes and the median number of free syringes they had received in the preceding month was 0. In the multivariable analysis, apart from injection-related variables, homelessness was a risk factor for HIV infection in male PWIDs [odds ratio (OR) yes versus no = 1.89, 95% confidence interval (CI) = 1.41, 2.52] while, in female PWIDS, the number of sexual partners (OR for > 5 versus one partner in the past year = 4.12, 95% CI = 1.93, 8.77) and history of imprisonment (OR yes versus no = 2.76, 95% CI = 1.43, 5.31) were associated with HIV. In Athens, Greece, the ARISTOTLE intervention for identifying HIV-positive people among people who inject drugs (PWID) facilitated rapid

  12. Evaluation of a multiple regression model for the forecasting of the concentrations of NOx and PM10 in Athens and Helsinki. (United States)

    Vlachogianni, A; Kassomenos, P; Karppinen, Ari; Karakitsios, S; Kukkonen, Jaakko


    Forecasting models based on stepwise multiple linear regression (MLR) have been developed for Athens and Helsinki. The predictor variables were the hourly concentrations of pollutants (NO, NO(2), NO(x), CO, O(3), PM(2.5) and PM(10)) and the meteorological variables (ambient temperature, wind speed/direction, and relative humidity) and in case of Helsinki also Monin-Obukhov length and mixing height of the present day. The variables to be forecasted are the maximum hourly concentrations of PM(10) and NO(x), and the daily average PM(10) concentrations of the next day. The meteorological pre-processing model MPP-FMI was used for computing the Monin-Obukhov length and the mixing height. The limitations of such statistical models include the persistence of both the meteorological and air quality situation; the model cannot account for rapid changes (on a temporal scale of hours or less than a day) that are commonly associated, e.g., with meteorological fronts, or episodes of a long-range transport origin. We have selected the input data for the model from one urban background and one urban traffic station both in Athens and Helsinki, in 2005. We have used various statistical evaluation parameters to analyze the performance of the models, and inter-compared the performance of the predictions for both cities. Forecasts from the MLR model were also compared to those from an Artificial Neural Network model (ANN) to investigate, if there are substantial gains that might justify the additional computational effort. The best predictor variables for both cities were the concentrations of NO(x) and PM(10) during the evening hours as well as wind speed, and the Monin-Obukhov length. In Athens, the index of agreement (IA) for NO(x) ranged from 0.77 to 0.84 and from 0.69 to 0.72, in the warm and cold periods of the year. In Helsinki, the corresponding values of IA ranged from 0.32 to 0.82 and from 0.67 to 0.86 for the warm and cold periods. In case of Helsinki the model accuracy was

  13. Calculation of reactor antineutrino spectra in TEXONO

    CERN Document Server

    Chen Dong Liang; Mao Ze Pu; Wong, T H


    In the low energy reactor antineutrino physics experiments, either for the researches of antineutrino oscillation and antineutrino reactions, or for the measurement of abnormal magnetic moment of antineutrino, the flux and the spectra of reactor antineutrino must be described accurately. The method of calculation of reactor antineutrino spectra was discussed in detail. Furthermore, based on the actual circumstances of NP2 reactors and the arrangement of detectors, the flux and the spectra of reactor antineutrino in TEXONO were worked out

  14. Propellant actuated nuclear reactor steam depressurization valve (United States)

    Ehrke, Alan C.; Knepp, John B.; Skoda, George I.


    A nuclear fission reactor combined with a propellant actuated depressurization and/or water injection valve is disclosed. The depressurization valve releases pressure from a water cooled, steam producing nuclear reactor when required to insure the safety of the reactor. Depressurization of the reactor pressure vessel enables gravity feeding of supplementary coolant water through the water injection valve to the reactor pressure vessel to prevent damage to the fuel core.

  15. Reactor Simulator Testing Overview (United States)

    Schoenfeld, Michael P.


    Test Objectives Summary: a) Verify operation of the core simulator, the instrumentation & control system, and the ground support gas and vacuum test equipment. b) Examine cooling & heat regeneration performance of the cold trap purification. c) Test the ALIP pump at voltages beyond 120V to see if the targeted mass flow rate of 1.75 kg/s can be obtained in the RxSim. Testing Highlights: a) Gas and vacuum ground support test equipment performed effectively for operations (NaK fill, loop pressurization, and NaK drain). b) Instrumentation & Control system effectively controlled loop temperature and flow rates or pump voltage to targeted settings and ramped within prescribed constraints. It effectively interacted with reactor simulator control model and defaulted back to temperature control mode if the transient fluctuations didn't dampen. c) Cold trap design was able to obtain the targeted cold temperature of 480 K. An outlet temperature of 636 K was obtained which was lower than the predicted 750 K but 156 K higher than the minimum temperature indicating the design provided some heat regeneration. d) ALIP produce a maximum flow rate of 1.53 kg/s at 800 K when operated at 150 V and 53 Hz.

  16. Reactor Simulator Testing (United States)

    Schoenfeld, Michael P.; Webster, Kenny L.; Pearson, Boise J.


    As part of the Nuclear Systems Office Fission Surface Power Technology Demonstration Unit (TDU) project, a reactor simulator test loop (RxSim) was design & built to perform integrated testing of the TDU components. In particular, the objectives of RxSim testing was to verify the operation of the core simulator, the instrumentation and control system, and the ground support gas and vacuum test equipment. In addition, it was decided to include a thermal test of a cold trap purification design and a pump performance test at pump voltages up to 150 V since the targeted mass flow rate of 1.75 kg/s was not obtained in the RxSim at the originally constrained voltage of 120 V. This paper summarizes RxSim testing. The gas and vacuum ground support test equipment performed effectively in NaK fill, loop pressurization, and NaK drain operations. The instrumentation and control system effectively controlled loop temperature and flow rates or pump voltage to targeted settings. The cold trap design was able to obtain the targeted cold temperature of 480 K. An outlet temperature of 636 K was obtained which was lower than the predicted 750 K but 156 K higher than the cold temperature indicating the design provided some heat regeneration. The annular linear induction pump (ALIP) tested was able to produce a maximum flow rate of 1.53 kg/s at 800 K when operated at 150 V and 53 Hz.

  17. Novel Catalytic Membrane Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Stuart Nemser, PhD


    There are many industrial catalytic organic reversible reactions with amines or alcohols that have water as one of the products. Many of these reactions are homogeneously catalyzed. In all cases removal of water facilitates the reaction and produces more of the desired chemical product. By shifting the reaction to right we produce more chemical product with little or no additional capital investment. Many of these reactions can also relate to bioprocesses. Given the large number of water-organic compound separations achievable and the ability of the Compact Membrane Systems, Inc. (CMS) perfluoro membranes to withstand these harsh operating conditions, this is an ideal demonstration system for the water-of-reaction removal using a membrane reactor. Enhanced reaction synthesis is consistent with the DOE objective to lower the energy intensity of U.S. industry 25% by 2017 in accord with the Energy Policy Act of 2005 and to improve the United States manufacturing competitiveness. The objective of this program is to develop the platform technology for enhancing homogeneous catalytic chemical syntheses.


    Lane, J.A.; Engberg, R.E.; Welch, J.M.


    A quick-releasing mechanism is described which may be used to rapidiy drop a device supported from beneath during normal use, such as a safety rod in a nuclear reactor. In accordance with this invention an electrical control signal, such as may be provided by radiation detection or other alarm condition sensing devices, is delivered to an electromagnetic solenoid, the armature of which is coupled to an actuating mechanism. The solenoid is energized when the mechanism is in its upper or cocked position. In such position, the mechanism engages a plurality of retaining balls, forcing them outward into engagement with a shoulder or recess in a corresponding section of a tubular extension on the upheld device. When the control signal to the solenoid suddenly ceases, the armature drops out, allowing the actuating mechanism to move slightly but rapidly under the force of a compressed spring. The weight of the device will urge the balls inward against a beveled portion of the actuating mechanism and away from the engaging section on the tubular extension, thus allowing the upheld device to fall freely under the influence of gravity.

  19. 78 FR 71675 - Update of the Office of Nuclear Reactor Regulation's Electronic Operating Reactor Correspondence (United States)


    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Update of the Office of Nuclear Reactor Regulation's Electronic Operating Reactor Correspondence... Regulatory Commission. Michele G. Evans, Director, Division of Operating Reactor Licensing, Office of Nuclear...

  20. Application of Multiple Linear Regression Models and Artificial Neural Networks on the Surface Ozone Forecast in the Greater Athens Area, Greece

    Directory of Open Access Journals (Sweden)

    K. P. Moustris


    Full Text Available An attempt is made to forecast the daily maximum surface ozone concentration for the next 24 hours, within the greater Athens area (GAA. For this purpose, we applied Multiple Linear Regression (MLR models against a forecasting model based on Artificial Neural Network (ANN approach. The availability of basic meteorological parameters is of great importance in order to forecast the ozone’s concentration levels. Modelling was based on recorded meteorological and air pollution data from thirteen monitoring sites within the GAA (network of the Hellenic Ministry of the Environment, Energy and Climate Change over five years from 2001 to 2005. The evaluation of the performance of the constructed models, using appropriate statistical indices, shows clearly that in every aspect, the prognostic model by far is the ANN model. This suggests that the ANN model can be used to issue warnings for the general population and mainly sensitive groups.

  1. The rattling sound of rattlesnakes (Crotalus viridis) as a communicative resource for ground squirrels (Spermophilus beecheyi) and burrowing owls (Athene cunicularia). (United States)

    Owings, Donald H; Rowe, Matthew P; Rundus, Aaron S


    Animal communication involves very dynamic processes that can generate new uses and functions for established communicative activities. In this article, the authors describe how an aposematic signal, the rattling sound of rattlesnakes (Crotalus viridis), has been exploited by 2 ecological associates of rattlesnakes: (a) California ground squirrels (Spermophilus beecheyi) use incidental acoustic cues in rattling sounds to assess the danger posed by the rattling snake, and (b) burrowing owls (Athene cunicularia) defend themselves against mammalian predators by mimicking the sound of rattling. The remarkable similarity between the burrowing owl's defensive hiss and the rattlesnake's rattling reflects both exaptation and adaptation. Such exploitation of the rattling sound has favored alternations in both the structure and the deployment of rattling by rattlesnakes.

  2. Durch Athen auf Frankfurt blicken ‚Austerity Urbanism‘, Uneven Development und Alltäglichkeit – Reflektionen aus zwei Workshops

    Directory of Open Access Journals (Sweden)

    Felix Wiegand


    Full Text Available Aufbauend auf den Erfahrungen zweier Workshops zu (urbaner Austerität in Griechenland und Deutschland diskutiert der Beitrag die (unterschiedliche Geschichte und Geographie der Austerität mit besonderem Blick auf die Regionen Frankfurt/Rhein-Main und Athen. Die Erfahrungen der multiplen Krise seit 2008, die sich in Griechenland vor dem Hintergrund einer austeritätspolitischen ‚Shock Doctrine’ und in der BRD im Kontext eines langfristigen Projekts der ‚scheibchenweisen’ Austerität entwickelten, eröffnen dabei die Möglichkeit, die Debatten um urbane Austerität einem kritischen Blick zu unterziehen. Der Beitrag sieht insbesondere im Bereich der Krisen der (urbanen sozialen Reproduktion sowie der Krisen der (städtischen Politik und Repräsentation weiteren Forschungsbedarf.

  3. Aerosol Activity and Hygroscopicity Combined with Lidar Data in the Urban Atmosphere of Athens, Greece in the Frame of the HYGRA_CD Campaign

    Directory of Open Access Journals (Sweden)

    Bougiatioti Aikaterini


    Full Text Available Measurements of cloud condensation nuclei (CCN concentrations between 0.2-1.0% supersaturation and aerosol size distribution were performed at an urban background site of Athens during HygrA-CD. The site is affected by local and long-range transported emissions as portrayed by the external mixing of the particles, as the larger ones appear to be more hygroscopic and more CCN-active than smaller ones. Activation fractions at all supersaturations exhibit a diurnal variability with minimum values around noon, which are considerably lower than unity. This reinforces the conclusion that the aerosol is mostly externally mixed between “fresher”, less hygroscopic components with more aged, CCN active constituents.

  4. Repairing liner of the reactor; Reparacion del liner del reactor

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar H, F. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)


    Due to the corrosion problems of the aluminum coating of the reactor pool, a periodic inspections program by ultrasound to evaluate the advance grade and the corrosion speed was settled down. This inspections have shown the necessity to repair some areas, in those that the slimming is significant, of not making it can arrive to the water escape of the reactor pool. The objective of the repair is to place patches of plates of 1/4 inch aluminum thickness in the areas of the reactor 'liner', in those that it has been detected by ultrasound a smaller thickness or similar to 3 mm. To carry out this the fuels are move (of the core and those that are decaying) to a temporary storage, the structure of the core is confined in a tank that this placed inside the pool of the reactor, a shield is placed in the thermal column and it is completely extracted the water for to leave uncover the 'liner' of the reactor. (Author)


    Johnson, B.M.


    A spray calcination reactor for calcining reprocessin- g waste solutions is described. Coaxial within the outer shell of the reactor is a shorter inner shell having heated walls and with open regions above and below. When the solution is sprayed into the irner shell droplets are entrained by a current of gas that moves downwardly within the inner shell and upwardly between it and the outer shell, and while thus being circulated the droplets are calcined to solids, whlch drop to the bottom without being deposited on the walls. (AEC) H03 H0233412 The average molecular weights of four diallyl phthalate polymer samples extruded from the experimental rheometer were redetermined using the vapor phase osmometer. An amine curing agent is required for obtaining suitable silver- filled epoxy-bonded conductive adhesives. When the curing agent was modified with a 47% polyurethane resin, its effectiveness was hampered. Neither silver nor nickel filler impart a high electrical conductivity to Adiprenebased adhesives. Silver filler was found to perform well in Dow-Corning A-4000 adhesive. Two cascaded hot-wire columns are being used to remove heavy gaseous impurities from methane. This purified gas is being enriched in the concentric tube unit to approximately 20% carbon-13. Studies to count low-level krypton-85 in xenon are continuing. The parameters of the counting technique are being determined. The bismuth isotopes produced in bismuth irradiated for polonium production are being determined. Preliminary data indicate the presence of bismuth207 and bismuth-210m. The light bismuth isotopes are probably produced by (n,xn) reactions bismuth-209. The separation of uranium-234 from plutonium-238 solutions was demonstrated. The bulk of the plutonium is removed by anion exchange, and the remainder is extracted from the uranium by solvent extraction techniques. About 99% of the plutonium can be removed in each thenoyltrifluoroacetone extraction. The viscosity, liquid density, and

  6. Entropy Production in Chemical Reactors (United States)

    Kingston, Diego; Razzitte, Adrián C.


    We have analyzed entropy production in chemically reacting systems and extended previous results to the two limiting cases of ideal reactors, namely continuous stirred tank reactor (CSTR) and plug flow reactor (PFR). We have found upper and lower bounds for the entropy production in isothermal systems and given expressions for non-isothermal operation and analyzed the influence of pressure and temperature in entropy generation minimization in reactors with a fixed volume and production. We also give a graphical picture of entropy production in chemical reactions subject to constant volume, which allows us to easily assess different options. We show that by dividing a reactor into two smaller ones, operating at different temperatures, the entropy production is lowered, going as near as 48 % less in the case of a CSTR and PFR in series, and reaching 58 % with two CSTR. Finally, we study the optimal pressure and temperature for a single isothermal PFR, taking into account the irreversibility introduced by a compressor and a heat exchanger, decreasing the entropy generation by as much as 30 %.

  7. Antineutrino monitoring of thorium reactors (United States)

    Akindele, Oluwatomi A.; Bernstein, Adam; Norman, Eric B.


    Various groups have demonstrated that antineutrino monitoring can be successful in assessing the plutonium content in water-cooled nuclear reactors for nonproliferation applications. New reactor designs and concepts incorporate nontraditional fuel types and chemistry. Understanding how these properties affect the antineutrino emission from a reactor can extend the applicability of antineutrino monitoring. Thorium molten salt reactors breed 233U, that if diverted constitute a direct use material as defined by the International Atomic Energy Agency (IAEA). The antineutrino spectrum from the fission of 233U has been estimated for the first time, and the feasibility of detecting the diversion of 8 kg of 233U, within a 30 day timeliness goal has been evaluated. The antineutrino emission from a thorium reactor operating under normal conditions is compared to a diversion scenario by evaluating the daily antineutrino count rate and the energy spectrum of the detected antineutrinos at a 25 m standoff. It was found that the diversion of a significant quantity of 233U could not be detected within the current IAEA timeliness detection goal using either tests. A rate-time based analysis exceeded the timeliness goal by 23 days, while a spectral based analysis exceeds this goal by 31 days.

  8. Simplifying Microbial Electrosynthesis Reactor Design

    Directory of Open Access Journals (Sweden)

    Cloelle G.S. Giddings


    Full Text Available Microbial electrosynthesis, an artificial form of photosynthesis, can efficiently convert carbon dioxide into organic commodities; however, this process has only previously been demonstrated in reactors that have features likely to be a barrier to scale-up. Therefore, the possibility of simplifying reactor design by both eliminating potentiostatic control of the cathode and removing the membrane separating the anode and cathode was investigated with biofilms of Sporomusa ovata, which reduces carbon dioxide to acetate. In traditional ‘H-cell’ reactors, where the anode and cathode chambers were separated with a proton-selective membrane, the rates and columbic efficiencies of microbial electrosynthesis remained high when electron delivery at the cathode was powered with a direct current power source rather than with a poteniostat-poised cathode utilized in previous studies. A membrane-less reactor with a direct-current power source with the cathode and anode positioned to avoid oxygen exposure at the cathode, retained high rates of acetate production as well as high columbic and energetic efficiencies. The finding that microbial electrosynthesis is feasible without a membrane separating the anode from the cathode, coupled with a direct current power source supplying the energy for electron delivery, is expected to greatly simplify future reactor design and lower construction costs.

  9. Rapid starting methanol reactor system (United States)

    Chludzinski, Paul J.; Dantowitz, Philip; McElroy, James F.


    The invention relates to a methanol-to-hydrogen cracking reactor for use with a fuel cell vehicular power plant. The system is particularly designed for rapid start-up of the catalytic methanol cracking reactor after an extended shut-down period, i.e., after the vehicular fuel cell power plant has been inoperative overnight. Rapid system start-up is accomplished by a combination of direct and indirect heating of the cracking catalyst. Initially, liquid methanol is burned with a stoichiometric or slightly lean air mixture in the combustion chamber of the reactor assembly. The hot combustion gas travels down a flue gas chamber in heat exchange relationship with the catalytic cracking chamber transferring heat across the catalyst chamber wall to heat the catalyst indirectly. The combustion gas is then diverted back through the catalyst bed to heat the catalyst pellets directly. When the cracking reactor temperature reaches operating temperature, methanol combustion is stopped and a hot gas valve is switched to route the flue gas overboard, with methanol being fed directly to the catalytic cracking reactor. Thereafter, the burner operates on excess hydrogen from the fuel cells.

  10. Gaseous fuel nuclear reactor research (United States)

    Schwenk, F. C.; Thom, K.


    Gaseous-fuel nuclear reactors are described; their distinguishing feature is the use of fissile fuels in a gaseous or plasma state, thereby breaking the barrier of temperature imposed by solid-fuel elements. This property creates a reactor heat source that may be able to heat the propellant of a rocket engine to 10,000 or 20,000 K. At this temperature level, gas-core reactors would provide the breakthrough in propulsion needed to open the entire solar system to manned and unmanned spacecraft. The possibility of fuel recycling makes possible efficiencies of up to 65% and nuclear safety at reduced cost, as well as high-thrust propulsion capabilities with specific impulse up to 5000 sec.

  11. Investigation of KW reactor incident

    Energy Technology Data Exchange (ETDEWEB)

    Sturges, D G [USAEC Hanford Operations Office, Richland, WA (United States); Hauff, T W; Greager, O H [General Electric Co., Richland, WA (United States). Hanford Atomic Products Operation


    The new KW reactor was placed in operation on January 4, 1955, and had been running at relatively low power levels for only 17 hours when it was shut down because of a process tube water leak which appeared to be associated with a slug rupture. After several days of unrewarding effort to remove the slugs and tube by customary methods, it developed that considerable melting of the tube and slugs had taken place. It was then evident that removal of the stuck mass and repairs to the damaged tube channel would require unusual measures that were certain to extend the reactor outage for several weeks. This report documents the work and findings of the Committee which investigated the KW reactor incident. Its content represents unanimous agreement among the three Committee members.

  12. STARFIRE: a commercial tokamak reactor

    Energy Technology Data Exchange (ETDEWEB)


    The purpose of this document is to provide an interim status report on the STARFIRE project for the period of May to September 1979. The basic objective of the STARFIRE project is to develop a design concept for a commercial tokamak fusion electric power plant based on the deuterium/tritium/lithium fuel cycle. The key technical objective is to develop the best embodiment of the tokamak as a power reactor consistent with credible engineering solutions to design problems. Another key goal of the project is to give careful attention to the safety and environmental features of a commercial fusion reactor.

  13. Fundamentals of Nuclear Reactor Physics

    CERN Document Server

    Lewis, E E


    This new streamlined text offers a one-semester treatment of the essentials of how the fission nuclear reactor works, the various approaches to the design of reactors, and their safe and efficient operation. The book includes numerous worked-out examples and end-of-chapter questions to help reinforce the knowledge presented. This textbook offers an engineering-oriented introduction to nuclear physics, with a particular focus on how those physics are put to work in the service of generating nuclear-based power, particularly the importance of neutron reactions and neutron behavior. Engin

  14. Analysis of Adiabatic Batch Reactor

    Directory of Open Access Journals (Sweden)

    Erald Gjonaj


    Full Text Available A mixture of acetic anhydride is reacted with excess water in an adiabatic batch reactor to form an exothermic reaction. The concentration of acetic anhydride and the temperature inside the adiabatic batch reactor are calculated with an initial temperature of 20°C, an initial temperature of 30°C, and with a cooling jacket maintaining the temperature at a constant of 20°C. The graphs of the three different scenarios show that the highest temperatures will cause the reaction to occur faster.

  15. United States Domestic Research Reactor Infrastructure - TRIGA Reactor Fuel Support

    Energy Technology Data Exchange (ETDEWEB)

    Morrell, Douglas [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415 (United States)


    The purpose of the United State Domestic Research Reactor Infrastructure Program is to provide fresh nuclear reactor fuel to United States universities at no, or low, cost to the university. The title of the fuel remains with the United States government and when universities are finished with the fuel, the fuel is returned to the United States government. The program is funded by the United States Department of Energy - Nuclear Energy division, managed by Department of Energy - Idaho Field Office, and contracted to the Idaho National Laboratory's Management and Operations Contractor - Battelle Energy Alliance. Program has been at Idaho since 1977 and INL subcontracts with 26 United States domestic reactor facilities (13 TRIGA facilities, 9 plate fuel facilities, 2 AGN facilities, 1 Pulstar fuel facility, 1 Critical facility). University has not shipped fuel since 1968 and as such, we have no present procedures for shipping spent fuel. In addition: floor loading rate is unknown, many interferences must be removed to allow direct access to the reactor tank, floor space in the reactor cell is very limited, pavement ends inside our fence; some of the surface is not finished. The whole approach is narrow, curving and downhill. A truck large enough to transport the cask cannot pull into the lot and then back out (nearly impossible / refused by drivers); a large capacity (100 ton), long boom crane would have to be used due to loading dock obstructions. Access to the entrance door is on a sidewalk. The campus uses it as a road for construction equipment, deliveries and security response. Large trees are on both sides of sidewalk. Spent fuel shipments have never been done, no procedures approved or in place, no approved casks, no accident or safety analysis for spent fuel loading. Any cask assembly used in this facility will have to be removed from one crane, moved on the floor and then attached to another crane to get from the staging area to the reactor room

  16. Request for Naval Reactors Comment on Proposed Prometheus Space Flight Nuclear Reactor High Tier Reactor Safety Requirements and for Naval Reactors Approval to Transmit These Requirements to JPL

    Energy Technology Data Exchange (ETDEWEB)

    D. Kokkinos


    The purpose of this letter is to request Naval Reactors comments on the nuclear reactor high tier requirements for the PROMETHEUS space flight reactor design, pre-launch operations, launch, ascent, operation, and disposal, and to request Naval Reactors approval to transmit these requirements to Jet Propulsion Laboratory to ensure consistency between the reactor safety requirements and the spacecraft safety requirements. The proposed PROMETHEUS nuclear reactor high tier safety requirements are consistent with the long standing safety culture of the Naval Reactors Program and its commitment to protecting the health and safety of the public and the environment. In addition, the philosophy on which these requirements are based is consistent with the Nuclear Safety Policy Working Group recommendations on space nuclear propulsion safety (Reference 1), DOE Nuclear Safety Criteria and Specifications for Space Nuclear Reactors (Reference 2), the Nuclear Space Power Safety and Facility Guidelines Study of the Applied Physics Laboratory.

  17. Reactor Antineutrino Signals at Morton and Boulby

    CERN Document Server

    Dye, Steve


    Increasing the distance from which an antineutrino detector is capable of monitoring the operation of a registered reactor, or discovering a clandestine reactor, strengthens the Non-Proliferation of Nuclear Weapons Treaty. This report presents calculations of reactor antineutrino interactions, from quasi-elastic neutrino-proton scattering and elastic neutrino-electron scattering, in a water-based detector operated >10 km from a commercial power reactor. It separately calculates signal from the proximal reactor and background from all other registered reactors. The main results are interaction rates and kinetic energy distributions of charged leptons scattered from quasi-elastic and elastic processes. Comparing signal and background distributions evaluates reactor monitoring capability. Scaling the results to detectors of different sizes, target media, and standoff distances is straightforward. Calculations are for two examples of a commercial reactor (P_th~3 GW) operating nearby (L~20 km) an underground facil...

  18. Reactivity control assembly for nuclear reactor (United States)

    Bollinger, Lawrence R.


    Reactivity control assembly for nuclear reactor comprises supports stacked above reactor core for holding control rods. Couplers associated with the supports and a vertically movable drive shaft have lugs at their lower ends for engagement with the supports.

  19. The Westinghouse Small Modular Reactor Design

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez Garcia, F. J.; Memmott, M. J.


    Westinghouse has developed a small modular reactor (SMR) which incorporates an integral pressurized water reactor (PWR) design. The Westinghouse SMR design also utilizes many of the key features and innovative concepts from the AP1000 plant, including passive safety systems.

  20. What can Recycling in Thermal Reactors Accomplish?

    Energy Technology Data Exchange (ETDEWEB)

    Steven Piet; Gretchen E. Matthern; Jacob J. Jacobson


    Thermal recycle provides several potential benefits when used as stop-gap, mixed, or backup recycling to recycling in fast reactors. These three roles involve a mixture of thermal and fast recycling; fast reactors are required to some degree at some time. Stop-gap uses thermal reactors only until fast reactors are adequately deployed and until any thermal-recycle-only facilities have met their economic lifetime. Mixed uses thermal and fast reactors symbiotically for an extended period of time. Backup uses thermal reactors only if problems later develop in the fast reactor portion of a recycling system. Thermal recycle can also provide benefits when used as pure thermal recycling, with no intention to use fast reactors. However, long term, the pure thermal recycling approach is inadequate to meet several objectives.

  1. An internally illuminated monolith reactor: Pros and cons relative to a slurry reactor

    NARCIS (Netherlands)

    Carneiro, Joana T.; Carneiro, J.T.; Berger, Rob; Moulijn, Jacob A.; Mul, Guido


    In the present study, kinetic models for the photo-oxidation of cyclohexane in two different photoreactor systems are discussed: a top illumination reactor (TIR) representative of a slurry reactor, and the so-called internally illuminated monolith reactor (IIMR) representing a reactor containing

  2. Operating limits Hanford Production Reactors. Revision 2

    Energy Technology Data Exchange (ETDEWEB)

    Owsley, G.F. [comp.


    This report is applicable to the eight operating production reactors, B, C, D, DR, F, H, KE, and KW. It covers the following: operating parameter limitations; reactivity limitations; control and safety systems; reactor fuel loading; coolant requirements with irradiated fuel in reactor; reactor confinement; test facilities; code compliance; safety instrumentation and set points; and control criteria. Also discussed are administrative procedures for process control, training, audits and inspection, and reports and records.

  3. Digital computer operation of a nuclear reactor (United States)

    Colley, R.W.


    A method is described for the safe operation of a complex system such as a nuclear reactor using a digital computer. The computer is supplied with a data base containing a list of the safe state of the reactor and a list of operating instructions for achieving a safe state when the actual state of the reactor does not correspond to a listed safe state, the computer selects operating instructions to return the reactor to a safe state.

  4. Monolithic reactor: higher yield, less energy


    Mols, B.


    The production of margarine, the desulphurisation of crude oil, and the manufacture of synthetic diesel fuel, these are only three of the many industrial processes in which a three-phase reactor is used. Traditionally, this type of reactor is rather ill-defined. Success with a lab scale set-up is no guarantee that a large commercial reactor will work. Scalability is less than perfect, one might say. Researchers at the Reactor & Catalysis Engineering epartment of the Chemical Technology facult...

  5. Reference worldwide model for antineutrinos from reactors


    Baldoncini, Marica; Callegari, Ivan; Fiorentini, Giovanni; Mantovani, Fabio; Ricci, Barbara; Strati, Virginia; Xhixha, Gerti


    Antineutrinos produced at nuclear reactors constitute a severe source of background for the detection of geoneutrinos, which bring to the Earth's surface information about natural radioactivity in the whole planet. In this framework we provide a reference worldwide model for antineutrinos from reactors, in view of reactors operational records yearly published by the International Atomic Energy Agency (IAEA). We evaluate the expected signal from commercial reactors for ongoing (KamLAND and Bor...

  6. Liquid metal cooled nuclear reactor plant system (United States)

    Hunsbedt, Anstein; Boardman, Charles E.


    A liquid metal cooled nuclear reactor having a passive cooling system for removing residual heat resulting for fuel decay during reactor shutdown, or heat produced during a mishap. The reactor system is enhanced with sealing means for excluding external air from contact with the liquid metal coolant leaking from the reactor vessel during an accident. The invention also includes a silo structure which resists attack by leaking liquid metal coolant, and an added unique cooling means.

  7. Hydrodynamics of a Monolithic Stirrer Reactor

    NARCIS (Netherlands)

    Kritzinger, H.P.


    The Monolithic Stirrer Reactor (MSR) is a novel concept for heterogeneously catalyzed reactors and is presented as an alternative device to slurry reactors. It uses a modified stirrer on which structured catalyst supports (monoliths) are fixed to form permeable blades. The monoliths consist of small

  8. Heat-pipe thermionic reactor concept

    DEFF Research Database (Denmark)

    Storm Pedersen, E.


    Main components are reactor core, heat pipe, thermionic converter, secondary cooling system, and waste heat radiator; thermal power generated in reactor core is transported by heat pipes to thermionic converters located outside reactor core behind radiation shield; thermionic emitters are in direct...

  9. Laminar Entrained Flow Reactor (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    None, None


    The Laminar Entrained Flow Reactor (LEFR) is a modular, lab scale, single-user reactor for the study of catalytic fast pyrolysis (CFP). This system can be employed to study a variety of reactor conditions for both in situ and ex situ CFP.

  10. New usage for old reactor

    NARCIS (Netherlands)

    Wassink, J.


    The latest measurement instrument of the TU Delft measures the crystal structures of many different materials and is unique within the Netherlands. The so-called Pearl neutron powder diffractometer was opened on 24 September at the RID reactor institute. “It is difficult to overestimate the

  11. Nuclear Reactors and Technology; (USA)

    Energy Technology Data Exchange (ETDEWEB)

    Cason, D.L.; Hicks, S.C. (eds.)


    Nuclear Reactors and Technology (NRT) announces on a monthly basis the current worldwide information available from the open literature on nuclear reactors and technology, including all aspects of power reactors, components and accessories, fuel elements, control systems, and materials. This publication contains the abstracts of DOE reports, journal articles, conference papers, patents, theses, and monographs added to the Energy Science and Technology Database (EDB) during the past month. Also included are US information obtained through acquisition programs or interagency agreements and international information obtained through the International Energy Agency's Energy Technology Data Exchange or government-to-government agreements. The digests in NRT and other citations to information on nuclear reactors back to 1948 are available for online searching and retrieval on EDB and Nuclear Science Abstracts (NSA) database. Current information, added daily to EDB, is available to DOE and its contractors through the DOE integrated Technical Information System. Customized profiles can be developed to provide current information to meet each user's needs.


    Miller, G.


    A nuclear reactor control rod mechanism is designed which mechanically moves the control rods into and out of the core under normal conditions but rapidly forces the control rods into the core by catapultic action in the event of an emergency. (AEC)

  13. Hb Melusine and Hb Athens-Georgia: potentially underreported in the Belgian population? Four cases demonstrating the lack of detection using common CE-HPLC methods either for glycated hemoglobin (HbA1C) analysis or Hb variant screening. (United States)

    Peeters, Bart; Brandt, Inger; Desmet, Koenraad; Harteveld, Cornelis L; Kieffer, Davy


    Suspected hemoglobin (Hb) variants, detected during HbA1C measurements should be further investigated, determining the extent of the interference with each method. This is the first report of Hb Melusine and Hb Athens-Georgia in Caucasian Belgian patients. Intervention & Technique: Since common CE-HPLC methods for HbA1C analysis or Hb variant screening are apparently unable to detect these Hb variants, their presence might be underestimated. HbA1C analysis using CZE, however, alerted for their presence. Moreover, in case of Hb Melusine, even Hb variant screening using CZE was unsuccessful in its detection. Fortunately, carriage of Hb Melusine or Hb Athens-Georgia variants has no clinical implications and, as shown in this report, no apparent difference in HbA1C should be expected.


    Busey, H.M.


    A homogeneous nuclear reactor utilizing a selfcirculating liquid fuel is described. The reactor vessel is in the form of a vertically disposed tubular member having the lower end closed by the tube walls and the upper end closed by a removal fianged assembly. A spherical reaction shell is located in the lower end of the vessel and spaced from the inside walls. The reaction shell is perforated on its lower surface and is provided with a bundle of small-diameter tubes extending vertically upward from its top central portion. The reactor vessel is surrounded in the region of the reaction shell by a neutron reflector. The liquid fuel, which may be a solution of enriched uranyl sulfate in ordinary or heavy water, is mainiained at a level within the reactor vessel of approximately the top of the tubes. The heat of the reaction which is created in the critical region within the spherical reaction shell forms steam bubbles which more upwardly through the tubes. The upward movement of these bubbles results in the forcing of the liquid fuel out of the top of these tubes, from where the fuel passes downwardly in the space between the tubes and the vessel wall where it is cooled by heat exchangers. The fuel then re-enters the critical region in the reaction shell through the perforations in the bottom. The upper portion of the reactor vessel is provided with baffles to prevent the liquid fuel from splashing into this region which is also provided with a recombiner apparatus for recombining the radiolytically dissociated moderator vapor and a control means.

  15. Heterogeneous Recycling in Fast Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Forget, Benoit; Pope, Michael; Piet, Steven J.; Driscoll, Michael


    Current sodium fast reactor (SFR) designs have avoided the use of depleted uranium blankets over concerns of creating weapons grade plutonium. While reducing proliferation risks, this restrains the reactor design space considerably. This project will analyze various blanket and transmutation target configurations that could broaden the design space while still addressing the non-proliferation issues. The blanket designs will be assessed based on the transmutation efficiency of key minor actinide (MA) isotopes and also on mitigation of associated proliferation risks. This study will also evaluate SFR core performance under different scenarios in which depleted uranium blankets are modified to include minor actinides with or without moderators (e.g. BeO, MgO, B4C, and hydrides). This will be done in an effort to increase the sustainability of the reactor and increase its power density while still offering a proliferation resistant design with the capability of burning MA waste produced from light water reactors (LWRs). Researchers will also analyze the use of recycled (as opposed to depleted) uranium in the blankets. The various designs will compare MA transmutation efficiency, plutonium breeding characteristics, proliferation risk, shutdown margins and reactivity coefficients with a current reference sodium fast reactor design employing homogeneous recycling. The team will also evaluate the out-of-core accumulation and/or burn-down rates of MAs and plutonium isotopes on a cycle-by-cycle basis. This cycle-by-cycle information will be produced in a format readily usable by the fuel cycle systems analysis code, VISION, for assessment of the sustainability of the deployment scenarios.

  16. Studying the urban thermal environment under a human-biometeorological point of view: The case of a large coastal metropolitan city, Athens (United States)

    Katavoutas, George; Georgiou, Giorgos K.; Asimakopoulos, Dimosthenis N.


    The thermal environment in modern cities has become potentially unfavorable and harmful for its residents, as a result of urbanization and industrialization. Exposure to these extreme thermal conditions increases the heat stress of people in cities considerably. In this context, the present study aims to investigate the urban thermal environment of the large coastal metropolitan city of Athens, in a human-biometeorologically significant way, utilizing the thermo-physiological assessment index PET. The analysis was based on three hour measurements derived from three-year datasets (2006-2009), at 12 monitoring sites located in the urban complex of Athens, on its boundaries and beyond them. The differences of PET values have been investigated in order to attribute urban and exurban thermal characteristics to the considered sites. The frequency and spatial distribution of PET as well as the urban/rural differences of PET have also been analyzed. Finally, a trend analysis has been applied in order to detect possible PET trends by employing long-term recording data (1985-2008). In terms of thermal human-biometeorological conditions, the analysis reveals that among the considered stations, those located inside the urban complex and the industrialized area present urban thermal characteristics, regardless the fact that they are installed either in a park and on a hill or at an open field. The spatial distribution of PET, at 0200 LST, shows a difference of about 3 to 4 °C, on the main axis of the city (SSW-NNE) in the summer period, while the difference exceeds 2.5 °C in the winter period. In general, cooler (less warm) thermal perception is observed at the north/northeast sites of the city as well as at the areas beyond the eastern boundaries of it. The PET differences between urban and rural sites hold a positive sign, except of those at 0500 LST and at 0800 LST. The highest differences are noted at 1400 LST and the most intense of them is noticed in the summer period

  17. Shutdown system for a nuclear reactor (United States)

    Groh, E.F.; Olson, A.P.; Wade, D.C.; Robinson, B.W.


    An ultimate shutdown system is provided for termination of neutronic activity in a nuclear reactor. The shutdown system includes bead chains comprising spherical containers suspended on a flexible cable. The containers are comprised of mating hemispherical shells which provide a ruggedized enclosure for reactor poison material. The bead chains, normally suspended above the reactor core on storage spools, are released for downward travel upon command from an external reactor monitor. The chains are capable of horizontal movement, so as to flow around obstructions in the reactor during their downward motion. 8 figs.

  18. Fast-acting nuclear reactor control device (United States)

    Kotlyar, Oleg M.; West, Phillip B.


    A fast-acting nuclear reactor control device for moving and positioning a fety control rod to desired positions within the core of the reactor between a run position in which the safety control rod is outside the reactor core, and a shutdown position in which the rod is fully inserted in the reactor core. The device employs a hydraulic pump/motor, an electric gear motor, and solenoid valve to drive the safety control rod into the reactor core through the entire stroke of the safety control rod. An overrunning clutch allows the safety control rod to freely travel toward a safe position in the event of a partial drive system failure.

  19. Tandem Mirror Reactor Systems Code (Version I)

    Energy Technology Data Exchange (ETDEWEB)

    Reid, R.L.; Finn, P.A.; Gohar, M.Y.; Barrett, R.J.; Gorker, G.E.; Spampinaton, P.T.; Bulmer, R.H.; Dorn, D.W.; Perkins, L.J.; Ghose, S.


    A computer code was developed to model a Tandem Mirror Reactor. Ths is the first Tandem Mirror Reactor model to couple, in detail, the highly linked physics, magnetics, and neutronic analysis into a single code. This report describes the code architecture, provides a summary description of the modules comprising the code, and includes an example execution of the Tandem Mirror Reactor Systems Code. Results from this code for two sensitivity studies are also included. These studies are: (1) to determine the impact of center cell plasma radius, length, and ion temperature on reactor cost and performance at constant fusion power; and (2) to determine the impact of reactor power level on cost.

  20. Reactor monitoring and safeguards using antineutrino detectors

    CERN Document Server

    Bowden, N S


    Nuclear reactors have served as the antineutrino source for many fundamental physics experiments. The techniques developed by these experiments make it possible to use these very weakly interacting particles for a practical purpose. The large flux of antineutrinos that leaves a reactor carries information about two quantities of interest for safeguards: the reactor power and fissile inventory. Measurements made with antineutrino detectors could therefore offer an alternative means for verifying the power history and fissile inventory of a reactors, as part of International Atomic Energy Agency (IAEA) and other reactor safeguards regimes. Several efforts to develop this monitoring technique are underway across the globe.

  1. Introduction to reactor internal materials for pressurized water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Woo Suk; Hong, Joon Hwa; Jee, Se Hwan; Lee, Bong Sang; Kuk, Il Hyun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)


    This report reviewed the R and D states of reactor internal materials in order to be a reference for researches and engineers who are concerning on localization of the materials in the field or laboratory. General structure of PWR internals and material specification for YGN 3 and 4 were reviewed. States-of-arts on R and D of stainless steel and Alloy X-750 were reviewed, and degradation mechanisms of the components were analyzed. In order to develop the good domestic materials for reactor internal, following studies would be carried out: microstructure, sensitization behavior, fatigue property, irradiation-induced stress corrosion cracking/radiation-induced segregation, radiation embrittlement. (Author) 7 refs., 14 figs., 5 tabs.,.

  2. Savannah River Site production reactor technical specifications. K Production Reactor

    Energy Technology Data Exchange (ETDEWEB)



    These technical specifications are explicit restrictions on the operation of the Savannah River Site K Production Reactor. They are designed to preserve the validity of the plant safety analysis by ensuring that the plant is operated within the required conditions bounded by the analysis, and with the operable equipment that is assumed to mitigate the consequences of an accident. Technical specifications preserve the primary success path relied upon to detect and respond to accidents. This report describes requirements on thermal-hydraulic limits; limiting conditions for operation and surveillance for the reactor, power distribution control, instrumentation, process water system, emergency cooling and emergency shutdown systems, confinement systems, plant systems, electrical systems, components handling, and special test exceptions; design features; and administrative controls.

  3. Nuclear reactor vessel fuel thermal insulating barrier (United States)

    Keegan, C. Patrick; Scobel, James H.; Wright, Richard F.


    The reactor vessel of a nuclear reactor installation which is suspended from the cold leg nozzles in a reactor cavity is provided with a lower thermal insulating barrier spaced from the reactor vessel that has a hemispherical lower section that increases in volume from the center line of the reactor to the outer extent of the diameter of the thermal insulating barrier and smoothly transitions up the side walls of the vessel. The space between the thermal insulating harrier and the reactor vessel forms a chamber which can be flooded with cooling water through passive valving to directly cool the reactor vessel in the event of a severe accident. The passive inlet valve for the cooling water includes a buoyant door that is normally maintained sealed under its own weight and floats open when the cavity is Hooded. Passively opening steam vents are also provided.

  4. Neutronics of a mixed-flow gas-core reactor

    Energy Technology Data Exchange (ETDEWEB)

    Soran, P.D.; Hansen, G.E.


    The study was made to investigate the neutronic feasibility of a mixed-flow gas-core reactor. Three reactor concepts were studied: four- and seven-cell radial reactors and a seven-cell scallop reactor. The reactors were fueled with UF/sub 6/ (either U-233 or U-235) and various parameters were varied. A four-cell reactor is not practical nor is the U-235 fueled seven-cell radial reactor; however, the 7-cell U-233 radial and scallop reactors can satisfy all design criteria. The mixed flow gas core reactor is a very attractive reactor concept and warrants further investigation.

  5. Advanced reactor physics methods for heterogeneous reactor cores (United States)

    Thompson, Steven A.

    To maintain the economic viability of nuclear power the industry has begun to emphasize maximizing the efficiency and output of existing nuclear power plants by using longer fuel cycles, stretch power uprates, shorter outage lengths, mixed-oxide (MOX) fuel and more aggressive operating strategies. In order to accommodate these changes, while still satisfying the peaking factor and power envelope requirements necessary to maintain safe operation, more complexity in commercial core designs have been implemented, such as an increase in the number of sub-batches and an increase in the use of both discrete and integral burnable poisons. A consequence of the increased complexity of core designs, as well as the use of MOX fuel, is an increase in the neutronic heterogeneity of the core. Such heterogeneous cores introduce challenges for the current methods that are used for reactor analysis. New methods must be developed to address these deficiencies while still maintaining the computational efficiency of existing reactor analysis methods. In this thesis, advanced core design methodologies are developed to be able to adequately analyze the highly heterogeneous core designs which are currently in use in commercial power reactors. These methodological improvements are being pursued with the goal of not sacrificing the computational efficiency which core designers require. More specifically, the PSU nodal code NEM is being updated to include an SP3 solution option, an advanced transverse leakage option, and a semi-analytical NEM solution option.

  6. Automatically scramming nuclear reactor system (United States)

    Ougouag, Abderrafi M.; Schultz, Richard R.; Terry, William K.


    An automatically scramming nuclear reactor system. One embodiment comprises a core having a coolant inlet end and a coolant outlet end. A cooling system operatively associated with the core provides coolant to the coolant inlet end and removes heated coolant from the coolant outlet end, thus maintaining a pressure differential therebetween during a normal operating condition of the nuclear reactor system. A guide tube is positioned within the core with a first end of the guide tube in fluid communication with the coolant inlet end of the core, and a second end of the guide tube in fluid communication with the coolant outlet end of the core. A control element is positioned within the guide tube and is movable therein between upper and lower positions, and automatically falls under the action of gravity to the lower position when the pressure differential drops below a safe pressure differential.


    Szilard, L.


    A nuclear reactor of the type which utilizes uranium fuel elements and a liquid coolant is described. The fuel elements are in the form of elongated tubes and are disposed within outer tubes extending through a tank containing heavy water, which acts as a moderator. The ends of the fuel tubes are connected by inlet and discharge headers, and liquid bismuth is circulated between the headers and through the fuel tubes for cooling. Helium is circulated through the annular space between the outer tubes in the tank and the fuel tubes to cool the water moderator to prevent boiling. The fuel tubes are covered with a steel lining, and suitable control means, heat exchange means, and pumping means for the coolants are provided to complete the reactor assembly.

  8. Growth, livability, feed consumption, and carcass composition of the Athens Canadian Random Bred 1955 meat-type chicken versus the 2012 high-yielding Cobb 500 broiler. (United States)

    Collins, K E; Kiepper, B H; Ritz, C W; McLendon, B L; Wilson, J L


    A flock of the Athens Canadian Random Bred (ACRB), a 1955 meat-type chicken control strain, was raised alongside a flock of 2012 Cobb 500 fast feathering high-yielding broilers to determine selection changes over the past 57 yr. All birds were reared under management practices appropriate for the Cobb 500. Birds were weighed weekly and processed at 6, 8, and 10 wk. Whole carcass, carcass parts, and organs were weighed. Modern broilers outweighed ACRB at every age, ranging from 3.7 to 4.7 times the size of the ACRB. All parts and organs were compared as a percentage of live fasted BW. The ACRB had significantly heavier feet, wings, internal organs, and feathers. The modern Cobb broiler had double the breast and larger leg muscles and had a significantly greater fat pad. Despite the larger muscle mass, the supply organs, the heart and lungs, were significantly smaller in the Cobb broiler than the ACRB as a percentage of BW. Relative size of supply and other vital organs should be given consideration for genetic selection of the future broiler. Comparisons of ACRB weights and organ percentages with past published data indicates that the ACRB remains a consistent control strain. ©2014 Poultry Science Association Inc.

  9. Food Habits of Spotted Owlet Athene brama (Temminck, 1821 in the Campus of Tropical Forest Research Institute, Jabalpur: an Ecological representation of Central India

    Directory of Open Access Journals (Sweden)

    Sanjay Paunikar


    Full Text Available The study on food habits of the Spotted Owlet, Athene brama (Temminck, 1821 in Tropical Forest Research Institute campus, Jabalpur, Madhya Pradesh, India was conducted in June 2011 to May 2012 by analyzing their regurgitated pellets. The insect order Coleoptera with three dung beetle species, Onitis philemon, Onitis virens, Onitis brahma and two orders and five species of small mammals, Mus booduga, Vandeleuria oleracea, Millardia meltada, Suncus etruscus and Suncus murinus were recorded from the pellets. The other insect taxa found in the pellets include Carabidae and Hydrophilidae beetles and Earwigs in the order Dermaptera. This is for the first time food habits of the spotted owlets, being reported from the state of Madhya Pradesh, which further provides identifying key characters of the dung beetles along with illustrations, obtained from the pellet materials. The study on the feeding habits of the owlet species is very important not only for its significance in conservation but also for their predatory potential, as they are the main predators of insects and non insect pests (rodents of forestry and agricultural importance.

  10. Widespread occurrence of bisphenol A diglycidyl ethers, p-hydroxybenzoic acid esters (parabens), benzophenone type-UV filters, triclosan, and triclocarban in human urine from Athens, Greece. (United States)

    Asimakopoulos, Alexandros G; Thomaidis, Nikolaos S; Kannan, Kurunthachalam


    Biomonitoring of human exposure to bisphenol A diglycidyl ethers (BADGEs; resin coating for food cans), p-hydroxybenzoic acid esters (parabens; preservatives), benzophenone-type UV filters (BP-UV filters; sunscreen agents), triclosan (TCS; antimicrobials), and triclocarban (TCC; antimicrobials) has been investigated in western European countries and North America. Nevertheless, little is known about the exposure of Greek populations to these environmental chemicals. In this study, 100 urine samples collected from Athens, Greece, were analyzed by liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) for the determination of total concentrations of five derivatives of BADGEs, six parabens and their metabolite (ethyl-protocatechuate), five derivatives of BP-UV filters, TCS, and TCC. Urinary concentrations of BADGEs, parabens, ethyl-protocatechuate, BP-UV filters, TCS and TCC (on a volume basis) ranged 0.3-20.9 (geometric mean: 0.9), 1.6-1010 (24.2), bisphenol A bis (2,3-dihydroxypropyl) ether (90%), ethyl paraben (87%), 2,4-dihydroxybenzophenone (78%), propyl paraben (72%), and TCS (71%). Estimated daily intakes (EDIurine), calculated on the basis of the measured urinary concentrations, ranged from 0.023 μg/kg bw/day for Σ5BADGEs to 31.4 μg/kg bw/day for Σ6Parabens. © 2013.

  11. Ventilatory and metabolic responses of burrowing owls, Athene cunicularia, to moderate and extreme hypoxia: analysis of the hypoxic ventilatory threshold vs. hemoglobin oxygen affinity relationship in birds. (United States)

    Kilgore, Delbert L; Boggs, Dona F; Kilgore, Trevor J; Colby, Conrad; Williams, Burl R; Bavis, Ryan W


    We measured ventilation, oxygen consumption and blood gases in burrowing owls (Athene cunicularia) breathing moderate and extreme hypoxic gas mixtures to determine their hypoxic ventilatory threshold (HVT) and to assess if they, like other birds and mammals, exhibit a relationship between HVT and hemoglobin O2 affinity (P(50)) of their blood. An earlier report of an attenuated ventilatory responsiveness of this species to hypoxia was enigmatic given the low O2 affinity (high P(50)) of burrowing owl hemoglobin. In the current study, burrowing owls breathing 11% and 9% O2 showed a significantly elevated total ventilation. The arterial partial pressure of oxygen (PaO2) at which ventilation is elevated above normoxic values in burrowing owls was 58 mm Hg. This threshold value conforms well to expectations based on the high P(50) of their hemoglobin and the HVT vs. P(50) relationship for birds developed in this study. Correcting for phylogenetic relatedness in the multi-species analysis had no effect on the HVT vs. P(50) relationship. Also, because burrowing owls in this study did not show a hypometabolic response at any level of hypoxia (even at 9% O2); HVT described in terms of percent change in oxygen convection requirement is identical to that based on ventilation alone.

  12. Aerosol optical depth as a measure of particulate exposure using imputed censored data, and relationship with childhood asthma hospital admissions for 2004 in athens, Greece. (United States)

    Higgs, Gary; Sterling, David A; Aryal, Subhash; Vemulapalli, Abhilash; Priftis, Kostas N; Sifakis, Nicolas I


    An understanding of human health implications from atmosphere exposure is a priority in both the geographic and the public health domains. The unique properties of geographic tools for remote sensing of the atmosphere offer a distinct ability to characterize and model aerosols in the urban atmosphere for evaluation of impacts on health. Asthma, as a manifestation of upper respiratory disease prevalence, is a good example of the potential interface of geographic and public health interests. The current study focused on Athens, Greece during the year of 2004 and (1) demonstrates a systemized process for aligning data obtained from satellite aerosol optical depth (AOD) with geographic location and time, (2) evaluates the ability to apply imputation methods to censored data, and (3) explores whether AOD data can be used satisfactorily to investigate the association between AOD and health impacts using an example of hospital admission for childhood asthma. This work demonstrates the ability to apply remote sensing data in the evaluation of health outcomes, that the alignment process for remote sensing data is readily feasible, and that missing data can be imputed with a sufficient degree of reliability to develop complete datasets. Individual variables demonstrated small but significant effect levels on hospital admission of children for AOD, nitrogen oxides (NOx), relative humidity (rH), temperature, smoke, and inversely for ozone. However, when applying a multivari-able model, an association with asthma hospital admissions and air quality could not be demonstrated. This work is promising and will be expanded to include additional years.

  13. Management of environmental health issues for the 2004 Athens Olympic Games: is enhanced integrated environmental health surveillance needed in every day routine operation?

    Directory of Open Access Journals (Sweden)

    Chervoni Julia


    Full Text Available Abstract Background Management of environmental health issues is an integral part of public health systems. An active integrated environmental health surveillance and response system was developed for the Athens Olympics to monitor and prevent exposure to environmental hazards. The potential for permanent implementation of the program was examined. Methods The environmental health surveillance and response system included standardization, computerization and electronic transmission of data concerning environmental inspections of 17 site categories (restaurants, swimming pools etc of public health interest, drinking and recreational water examinations and suggested corrective actions. The Olympic Planning Unit integrated and centrally managed data from 13 public health agencies, recommended, supervised and coordinated prompt corrective actions. Methods used to test the effectiveness of the program were the assessment of water quality test and inspection results trends over time using linear regression and epidemiological surveillance findings. Results Between January 2003 and September the 30th, 2004, 196 inspectors conducted 8562 inspections, collected 5024 water samples and recommended 17 027 corrective actions. In 10 cruise ships used as floating hotels inspectors conducted 10 full inspections, 2 re-inspections, and 27 follow-up inspections. Unsatisfactory inspection results (r = 0.44, p Conclusion Lessons learned for future events include timely implementation and installation of communication processes, and rapid and coordinated response to unsatisfactory inspection results. Routine national programs need to adopt enhanced environmental health surveillance aimed at public health decision-making, but with a different perspective.

  14. Histological analysis of the eyeball of Neotropical birds of prey Caracara plancus, Falco sparverius, Rupornis magnirostris, Megascops choliba and Athene cunicularia

    Directory of Open Access Journals (Sweden)

    Débora Galdino Pinto


    Full Text Available The growing use of ophthalmic examination as a screening tool in birds intended for reintroduction into natural environments over the last few years has given renewed significance to avian ophthalmology in the context of free-ranging and captive bird conservation. The eye plays a vital role in prey detection and capture by birds of prey. The remarkable eyesight of such birds makes them interesting subjects for avian visual system anatomical and histological investigation. This study set out to describe histological features of the eyeball of ubiquitous birds of prey in Brazil (Falconiformes, Accipitriformes and Strigiformes. Twenty enucleated cadaveric eyeballs obtained from birds with natural death, Caracara plancus, Falco sparverius, Rupornis magnirostris, Megascops choliba and Athene cunicularia were used. Routinely prepared histological slides stained with hematoxylin and eosin were analyzed under light microscopy. Similarities and variations in ocular structures between the different bird species studied were highlighted in this study, with major differences concerning the lens and retina. This study highlights the importance of determining the ocular histological pattern of the species so they can be better understood. These results may well assign baseline information of the species and assist in eye histopathological diagnostics.

  15. A Survey of Removable Partial Denture (RPD) Retentive Elements in Relation to the Type of Edentulism and Abutment Teeth Found in Commercial Laboratories, Athens, Greece (United States)

    Sotiriou, Michael; Zissis, Alcibiades


    Objective The aim of this survey was to record removable partial denture (RPD) retentive elements and abutment teeth in partially edentulous patients, identified in commercial laboratories in Athens, Greece. Material and Methods 628 master casts with the corresponding cast metal frameworks used in the construction of RPDs were evaluated. Casts were photographed to identify the number and position of existing teeth, the partial edentulism class and the retentive elements. Prevalence tables and the x2 test were used for the statistical analysis of the collected data (α=.05). Results There were 276 maxillary (43.9%) and 352 (56.1%) mandibular casts. Maxillary edentulism entailed almost a total absence of right third molars in 96.7% and left third molars 96.0% of casts, with lower rates for the first and second molars. Edentulism in the posterior mandible presented a similar pattern. The most profound findings concerning retentive elements were: 91.9% of the retainers used were clasps and the remaining 8.1% were attachments. Of the clasps used, 48.9% were of the Roach Τ type, a finding more common in Kennedy Class I as compared to other Kennedy Classes (p<0.01). The circumferential clasps accounted for 19.3% of the total clasps used, and it was less frequently presented (8.8%) in Kennedy I Classes (p<0.01). Conclusions Roach clasps were used in the majority of cases whereas RPI clasps and attachments were rarely used. PMID:27688367

  16. A case-control study of hopelessness and suicidal behavior in the city of Athens, Greece. The role of the financial crisis. (United States)

    Christodoulou, Christos; Efstathiou, Vasiliki; Michopoulos, Ioannis; Ferentinos, Panagiotis; Korkoliakou, Panagiota; Gkerekou, Maria; Bouras, Georgios; Papadopoulou, Athanasia; Papageorgiou, Charalabos; Douzenis, Athanassios


    This study aimed to examine the psychometric properties of Beck Hopelessness Scale (BHS) in Greek patients with a recent suicide attempt, the predictive ability of BHS especially in terms of age and the possible effect of the financial crisis on hopelessness as it has been identified as a significant suicide risk factor. The study included a total of 510 individuals, citizens of Athens, Greece. Three hundred and forty individuals (170 attempted suicide patients, and 170 -age and gender- matched healthy individuals used as controls) completed BHS before the financial crisis onset (from 2009 to 2010). A sample of 170 healthy individuals also completed the BHS after the financial crisis onset (from 2013 to 2014), when the impact of the austerity measures was being felt by the Greek society. The Greek BHS version demonstrated good psychometric properties and a sufficient degree of internal consistency. Attempted suicide patients (M = 9) presented higher hopelessness than the controls (M = 3). The patients' age positively correlated with hopelessness (rs = .35, p  .05) the crisis onset. Nevertheless, regarding the latter group, the women, the younger individuals, the less educated, the unemployed and the participants with low or mediocre self-reported financial status presented increased hopelessness. Our findings suggest that BHS could be a useful instrument especially when screening for suicide risk in people of older age, and that the financial crisis in Greece had a greater impact on subgroups of the population regarding hopelessness.

  17. A mathematical programming framework for energy planning in services' sector buildings under uncertainty in load demand: The case of a hospital in Athens

    Energy Technology Data Exchange (ETDEWEB)

    Mavrotas, George; Diakoulaki, Danae; Florios, Kostas; Georgiou, Paraskevas [Laboratory of Industrial and Energy Economics, School of Chemical Engineering, National Technical University of Athens, Zografou Campus, 15780 Athens (Greece)


    The aim of this paper is to provide an integrated modeling and optimization framework for energy planning in large consumers of the services' sector based on mathematical programming. The power demand is vaguely known and the underlying uncertainty is modeled using elements from fuzzy set theory. The defined fuzzy programming model is subsequently transformed to an equivalent multi-objective problem, where the minimization of cost and the maximization of demand satisfaction are the objective functions. The Pareto optimal solutions of this problem are obtained using a novel version of the {epsilon}-constraint method and represent the possibly optimal solutions of the original problem under uncertainty. In the present case, in order to select the most preferred Pareto optimal solution, the minimax regret criterion is properly used to indicate the preferred configuration of the system (i.e. the size of the installed units) given the load uncertainty. Furthermore, the paper proposes a model reduction technique that can be used in similar cases and further examines its effect in the final results. The above methodology is applied to the energy rehabilitation of a hospital in the Athens area. The technologies under consideration include a combined heat and power unit for providing power and heat, an absorption unit and/or a compression unit for providing cooling load. The obtained results demonstrate that, increasing the degree of demand satisfaction, the total annual cost increases almost linearly. Although data compression allows obtaining realistic results, the size of the proposed units might be slightly changed. (author)

  18. Reactor vessel lower head integrity

    Energy Technology Data Exchange (ETDEWEB)

    Rubin, A.M.


    On March 28, 1979, the Three Mile Island Unit 2 (TMI-2) nuclear power plant underwent a prolonged small break loss-of-coolant accident that resulted in severe damage to the reactor core. Post-accident examinations of the TMI-2 reactor core and lower plenum found that approximately 19,000 kg (19 metric tons) of molten material had relocated onto the lower head of the reactor vessel. Results of the OECD TMI-2 Vessel Investigation Project concluded that a localized hot spot of approximately 1 meter diameter had existed on the lower head. The maximum temperature on the inner surface of the reactor pressure vessel (RPV) in this region reached 1100{degrees}C and remained at that temperature for approximately 30 minutes before cooling occurred. Even under the combined loads of high temperature and high primary system pressure, the TMI-2 RPV did not fail. (i.e. The pressure varied from about 8.5 to 15 MPa during the four-hour period following the relocation of melt to the lower plenum.) Analyses of RPV failure under these conditions, using state-of-the-art computer codes, predicted that the RPV should have failed via local or global creep rupture. However, the vessel did not fail; and it has been hypothesized that rapid cooling of the debris and the vessel wall by water that was present in the lower plenum played an important role in maintaining RPV integrity during the accident. Although the exact mechanism(s) of how such cooling occurs is not known, it has been speculated that cooling in a small gap between the RPV wall and the crust, and/or in cracks within the debris itself, could result in sufficient cooling to maintain RPV integrity. Experimental data are needed to provide the basis to better understand these phenomena and improve models of RPV failure in severe accident codes.


    Tonks, L.


    A control device surrounding the active portion of a nuclear reactor is described. The control device consists of a plurality of contiguous cylinders partly filled with a neutron absorbing material and partly filled with a neutron reflecting material, each cylinder having a longitudinal reentrant surface into which a portion of an adjacent cylinder extends, one of the cylinders having two re-entrant surfaces, and means for rotating the cylinders one at a time. (AEC)


    Dietrich, J.R.; Harrer, J.M.


    A device is described for rapidly cortrolling the reactivity of an active portion of a reactor. The inveniion consists of coaxially disposed members each having circumferenital sections of material having dlfferent neutron absorbing characteristics and means fur moving the members rotatably and translatably relative to each other within the active portion to vary the neutron flux therein. The angular and translational movements of any member change the neutron flux shadowing effect of that member upon the other member.

  1. Reactor safeguards against insider sabotage

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, H.A.


    A conceptual safeguards system is structured to show how both reactor operations and physical protection resources could be integrated to prevent release of radioactive material caused by insider sabotage. Operational recovery capabilities are addressed from the viewpoint of both detection of and response to disabled components. Physical protection capabilities for preventing insider sabotage through the application of work rules are analyzed. Recommendations for further development of safeguards system structures, operational recovery, and sabotage prevention are suggested.

  2. Nuclear reactor power monitoring device

    Energy Technology Data Exchange (ETDEWEB)

    Tarumi, Teruji; Oda, Naotaka; Goto, Yasushi; Ito, Toshiaki [Toshiba Corp., Kawasaki, Kanagawa (Japan); Mitsubori, Minehisa


    The present invention provides a nuclear power monitoring device which does not lose a safety protection function even upon occurrence of a single failure in an APRM system of a BWR type reactor. Namely, an APRM for inputting signals of local power region monitors (LPRM) has four channels. Each of the channels is constituted so as to be bypassed. With such a constitution, LPRM detector signals can be inputted one by one to each of the four channels of the APRM from each of the LPRM detector assembly. Accordingly, a common channel for LPRM detectors can be eliminated in a small-sized reactor. The number of signals of the LPRM detectors inputted to each of the channels of the APRM is increased in a large-scaled reactor. Since each of the APRM can be bypassed, even if a single failure of one APRM is caused during a predetermined maintenance, the monitoring can be conducted smoothly by bypassing other channel. As a result, a multiple safe-protection function can be ensured. (I.S.)

  3. Actinide transmutation in nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Bultman, J.H.


    An optimization method is developed to maximize the burning capability of the ALMR while complying with all constraints imposed on the design for reliability and safety. This method leads to a maximal transuranics enrichment, which is being limited by constraints on reactivity. The enrichment can be raised by using the neutrons less efficiently by increasing leakage from the fuel. With the developed optimization method, a metallic and an oxide fueled ALMR were optimized. Both reactors perform equally well considering the burning of transuranics. However, metallic fuel has a much higher heat conductivity coefficient, which in general leads to better safety characteristics. In search of a more effective waste transmuter, a modified Molten Salt Reactor was designed. A MSR operates on a liquid fuel salt which makes continuous refueling possible, eliminating the issue of the burnup reactivity loss. Also, a prompt negative reactivity feedback is possible for an overmoderated reactor design, even when the Doppler coefficient is positive, due to the fuel expansion with fuel temperature increase. Furthermore, the molten salt fuel can be reprocessed based on a reduction process which is not sensitive to the short-lived spontaneously fissioning actinides. (orig./HP).

  4. The ARIES tokamak reactor study

    Energy Technology Data Exchange (ETDEWEB)


    The ARIES study is a community effort to develop several visions of tokamaks as fusion power reactors. The aims are to determine the potential economics, safety, and environmental features of a range of possible tokamak reactors, and to identify physics and technology areas with the highest leverage for achieving the best tokamak reactor. Three ARIES visions are planned, each having a different degree of extrapolation from the present data base in physics and technology. The ARIES-I design assumes a minimum extrapolation from current tokamak physics (e.g., 1st stability) and incorporates technological advances that can be available in the next 20 to 30 years. ARIES-II is a DT-burning tokamak which would operate at a higher beta in the 2nd MHD stability regime. It employs both potential advances in the physics and expected advances in technology and engineering. ARIES-II will examine the potential of the tokamak and the D{sup 3}He fuel cycle. This report is a collection of 14 papers on the results of the ARIES study which were presented at the IEEE 13th Symposium on Fusion Engineering (October 2-6, 1989, Knoxville, TN). This collection describes the ARIES research effort, with emphasis on the ARIES-I design, summarizing the major results, the key technical issues, and the central conclusions.

  5. Prospects for Tokamak Fusion Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Sheffield, J.; Galambos, J.


    This paper first reviews briefly the status and plans for research in magnetic fusion energy and discusses the prospects for the tokamak magnetic configuration to be the basis for a fusion power plant. Good progress has been made in achieving fusion reactor-level, deuterium-tritium (D-T) plasmas with the production of significant fusion power in the Joint European Torus (up to 2 MW) and the Tokamak Fusion Test Reactor (up to 10 MW) tokamaks. Advances on the technologies of heating, fueling, diagnostics, and materials supported these achievements. The successes have led to the initiation of the design phases of two tokamaks, the International Thermonuclear Experimental Reactor (ITER) and the US Toroidal Physics Experiment (TPX). ITER will demonstrate the controlled ignition and extended bum of D-T plasmas with steady state as an ultimate goal. ITER will further demonstrate technologies essential to a power plant in an integrated system and perform integrated testing of the high heat flux and nuclear components required to use fusion energy for practical purposes. TPX will complement ITER by testing advanced modes of steady-state plasma operation that, coupled with the developments in ITER, will lead to an optimized demonstration power plant.

  6. Reference worldwide model for antineutrinos from reactors (United States)

    Baldoncini, Marica; Callegari, Ivan; Fiorentini, Giovanni; Mantovani, Fabio; Ricci, Barbara; Strati, Virginia; Xhixha, Gerti


    Antineutrinos produced at nuclear reactors constitute a severe source of background for the detection of geoneutrinos, which bring to the Earth's surface information about natural radioactivity in the whole planet. In this framework, we provide a reference worldwide model for antineutrinos from reactors, in view of reactors operational records yearly published by the International Atomic Energy Agency. We evaluate the expected signal from commercial reactors for ongoing (KamLAND and Borexino), planned (SNO +), and proposed (Juno, RENO-50, LENA, and Hanohano) experimental sites. Uncertainties related to reactor antineutrino production, propagation, and detection processes are estimated using a Monte Carlo-based approach, which provides an overall site-dependent uncertainty on the signal in the geoneutrino energy window on the order of 3%. We also implement the off-equilibrium correction to the reference reactor spectra associated with the long-lived isotopes, and we estimate a 2.4% increase of the unoscillated event rate in the geoneutrino energy window due to the storage of spent nuclear fuels in the cooling pools. We predict that the research reactors contribute to less than 0.2% to the commercial reactor signal in the investigated 14 sites. We perform a multitemporal analysis of the expected reactor signal over a time lapse of ten years using reactor operational records collected in a comprehensive database published at

  7. Advanced Safeguards Approaches for New Fast Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Durst, Philip C.; Therios, Ike; Bean, Robert; Dougan, A.; Boyer, Brian; Wallace, Rick L.; Ehinger, Michael H.; Kovacic, Don N.; Tolk, K.


    This third report in the series reviews possible safeguards approaches for new fast reactors in general, and the ABR in particular. Fast-neutron spectrum reactors have been used since the early 1960s on an experimental and developmental level, generally with fertile blanket fuels to “breed” nuclear fuel such as plutonium. Whether the reactor is designed to breed plutonium, or transmute and “burn” actinides depends mainly on the design of the reactor neutron reflector and the whether the blanket fuel is “fertile” or suitable for transmutation. However, the safeguards issues are very similar, since they pertain mainly to the receipt, shipment and storage of fresh and spent plutonium and actinide-bearing “TRU”-fuel. For these reasons, the design of existing fast reactors and details concerning how they have been safeguarded were studied in developing advanced safeguards approaches for the new fast reactors. In this regard, the design of the Experimental Breeder Reactor-II “EBR-II” at the Idaho National Laboratory (INL) was of interest, because it was designed as a collocated fast reactor with a pyrometallurgical reprocessing and fuel fabrication line – a design option being considered for the ABR. Similarly, the design of the Fast Flux Facility (FFTF) on the Hanford Site was studied, because it was a successful prototype fast reactor that ran for two decades to evaluate fuels and the design for commercial-scale fast reactors.

  8. A simple model of reactor cores for reactor neutrino flux calculations for the KamLAND experiment

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, K. [Research Center for Neutrino Science, Tohoku University, Sendai 980-8578 (Japan)]. E-mail:; Inoue, K. [Research Center for Neutrino Science, Tohoku University, Sendai 980-8578 (Japan); Owada, K. [Research Center for Neutrino Science, Tohoku University, Sendai 980-8578 (Japan); Suekane, F. [Research Center for Neutrino Science, Tohoku University, Sendai 980-8578 (Japan); Suzuki, A. [Research Center for Neutrino Science, Tohoku University, Sendai 980-8578 (Japan); Hirano, G. [TEPCO Systems Corporation, Tokyo 135-0034 (Japan); Kosaka, S. [TEPCO Systems Corporation, Tokyo 135-0034 (Japan); Ohta, T. [Tokyo Electric Power Company, Tokyo 100-8560 (Japan); Tanaka, H. [Tokyo Electric Power Company, Tokyo 100-8560 (Japan)


    KamLAND is a reactor neutrino oscillation experiment with a very long baseline. This experiment successfully measured oscillation phenomena of reactor antineutrinos coming mainly from 53 reactors in Japan. In order to extract the results, it is necessary to accurately calculate time-dependent antineutrino spectra from all the reactors. A simple model of reactor cores and code implementing it were developed for this purpose. This paper describes the model of the reactor cores used in the KamLAND reactor analysis.

  9. Mechanical systems development of integral reactor

    Energy Technology Data Exchange (ETDEWEB)

    Park, Keun Bae; Chang, M. H.; Kim, J. I.; Choi, S.; Kim, K. S.; Kim, T. W.; Jeong, K. H.; Kim, J. H.; Kim, Y. W.; Lee, G. M.


    While Korean nuclear reactor strategy seems to remain focused on the large capacity power generation, it is expected that demand of small and medium size reactor will arise for multi-purpose applications such as small capacity power generation, co-generation and sea water desalination. This in mind, survey has been made on the worldwide small and medium integral reactors under development. Reviewed are their technical characteristics, development status, design features, application plans, etc. For the mechanical design scope of work, the structural concept compatible with the characteristics and requirements of integral reactor has been established. Types of major components were evaluated and selected. Functional and structural concept, equipment layout and supporting concept within the reactor pressure vessel have also been established. Preliminary mechanical design requirements were developed considering the reactor lifetime, operation conditions, and the expected loading combinations. To embody the concurrent design approach, recent CAD technology and team engineering concept were evaluated. (author). 31 refs.,16 tabs., 35 figs.

  10. Profiling a reactor component using ultrasonics

    Energy Technology Data Exchange (ETDEWEB)

    Pathak, L.; Seshadri, V.R.; Kumaravadivelu, C.; Sreenivasan, G.; Raghunathan, V.S. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India)


    Nuclear reactors have many components within the reactor vessel. During the life of a reactor it is possible for these components to be displaced or deformed because of the thermal cycles to which they are subject. Also, these components in situ therefore becomes important for the upkeep of the reactor. However, high radiation levels make it difficult to monitor using optical methods. This paper describes an ultrasonic method which was successfully employed in profiling a deformed guide tube of a reactor. The method uses the well-known ultrasonic ranging technique. However, the specialty of the method is the use of air transducers at 40 kHz to overcome the inherent divergence problems and the difficulties associated with high temperatures inherent in a sodium cooled reactor.

  11. Performance of a multipurpose research electrochemical reactor

    Energy Technology Data Exchange (ETDEWEB)

    Henquin, E.R. [Programa de Electroquimica Aplicada e Ingenieria Electroquimica (PRELINE), Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santiago del Estero 2829, S3000AOM Santa Fe (Argentina); Bisang, J.M., E-mail: [Programa de Electroquimica Aplicada e Ingenieria Electroquimica (PRELINE), Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santiago del Estero 2829, S3000AOM Santa Fe (Argentina)


    Highlights: > For this reactor configuration the current distribution is uniform. > For this reactor configuration with bipolar connection the leakage current is small. > The mass-transfer conditions are closely uniform along the electrode. > The fluidodynamic behaviour can be represented by the dispersion model. > This reactor represents a suitable device for laboratory trials. - Abstract: This paper reports on a multipurpose research electrochemical reactor with an innovative design feature, which is based on a filter press arrangement with inclined segmented electrodes and under a modular assembly. Under bipolar connection, the fraction of leakage current is lower than 4%, depending on the bipolar Wagner number, and the current distribution is closely uniform. When a turbulence promoter is used, the local mass-transfer coefficient shows a variation of {+-}10% with respect to its mean value. The fluidodynamics of the reactor responds to the dispersion model with a Peclet number higher than 10. It is concluded that this reactor is convenient for laboratory research.

  12. Introduction to the neutron kinetics of nuclear power reactors

    CERN Document Server

    Tyror, J G; Grant, P J


    An Introduction to the Neutron Kinetics of Nuclear Power Reactors introduces the reader to the neutron kinetics of nuclear power reactors. Topics covered include the neutron physics of reactor kinetics, feedback effects, water-moderated reactors, fast reactors, and methods of plant control. The reactor transients following faults are also discussed, along with the use of computers in the study of power reactor kinetics. This book is comprised of eight chapters and begins with an overview of the reactor physics characteristics of a nuclear power reactor and their influence on system design and

  13. Structures and Materials of Reactor Internals for PWR in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D. W.; Kim, W. S.; Kwon, S. C.; Kwon, J. H.; Kim, Y. S.; Kim, H. P.; Yoo, C. S.; Lee, S. R.; Jung, M. K.; Hwang, S. S


    Nuclear reactor types in Korea are PWR type reactor (Westinghouse, Combustion Engineering, Farmatome type) and CANDU type reactor. Structures and Materials for reactor internal of PWR type were investigated. Reactor internal was composed of lower core support structure, upper core support assembly, incore instrumentation support structure. Lower core support structure of these structures is the most important. The major material for the reactor internal is type 304 and 316 stainless steel and radial support clevis bolts are made of Inconel. The main damage mechanism for reactor internal was IASCC and the effect of IASCC on reactor internal was investigated. The accident for reactor internal was also investigate.

  14. Contribution of reactor physics in past and future. Is reactor physics useful?

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Toshikazu [Osaka Univ. (Japan); Kosaka, Shinya [TEPCO Systems Co. (Japan); Tatsumi, Masahiro [Nuclear Fuel Industries Ltd., Tokyo (Japan)] (and others)


    Reactor Physics is a science to create rector and to play an important role in application to calculation science and safety evaluation. This feature articles contains topics, interested problems and development problems in the following field of reactor physics such as theory and experiment of reactor physics, core control, safety evaluation, criticality safety, accelerator driven subcritical reactor (ADS), new type reactor and evaluation of reactor physics. An original nuclear calculation method developed in Japan has been applied to design and analysis of fast breeder reactor. Interested problems are a proposal of fundamental principles of progressive reactor, development of calculation science, new knowledge by application of best estimate method to safety evaluation and investigation of complicated phenomena of criticality safety. (S.Y.)

  15. Microstructured reactors for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Aartun, Ingrid


    Small scale hydrogen production by partial oxidation (POX) and oxidative steam reforming (OSR) have been studied over Rh-impregnated microchannel Fecralloy reactors and alumina foams. Trying to establish whether metallic microchannel reactors have special advantages for hydrogen production via catalytic POX or OSR with respect to activity, selectivity and stability was of special interest. The microchannel Fecralloy reactors were oxidised at 1000 deg C to form a {alpha}-Al2O3 layer in the channels in order to enhance the surface area prior to impregnation. Kr-BET measurements showed that the specific surface area after oxidation was approximately 10 times higher than the calculated geometric surface area. Approximately 1 mg Rh was deposited in the channels by impregnation with an aqueous solution of RhCl3. Annular pieces (15 mm o.d.,4 mm i.d., 14 mm length) of extruded {alpha}-Al2O3 foams were impregnated with aqueous solutions of Rh(NO3)3 to obtain 0.01, 0.05 and 0.1 wt.% loadings, as predicted by solution uptake. ICP-AES analyses showed that the actual Rh loadings probably were higher, 0.025, 0.077 and 0.169 wt.% respectively. One of the microchannel Fecralloy reactors and all Al2O3 foams were equipped with a channel to allow for temperature measurement inside the catalytic system. Temperature profiles obtained along the reactor axes show that the metallic microchannel reactor is able to minimize temperature gradients as compared to the alumina foams. At sufficiently high furnace temperature, the gas phase in front of the Rh/Al2O3/Frecralloy microchannel reactor and the 0.025 wt.% Rh/Al2O3 foams ignites. Gas phase ignition leads to lower syngas selectivity and higher selectivity to total oxidation products and hydrocarbon by-products. Before ignition of the gas phase the hydrogen selectivity is increased in OSR as compared to POX, the main contribution being the water-gas shift reaction. After gas phase ignition, increased formation of hydrocarbon by

  16. Fission control system for nuclear reactor (United States)

    Conley, G.H.; Estes, G.P.

    Control system for nuclear reactor comprises a first set of reactivity modifying rods fixed in a reactor core with their upper ends stepped in height across the core, and a second set of reactivity modifying rods movable vertically within the reactor core and having their lower ends stepped to correspond with the stepped arrangement of the first set of rods, pairs of the rods of the first and second sets being in coaxial alignment.

  17. Nuclear reactor shield including magnesium oxide (United States)

    Rouse, Carl A.; Simnad, Massoud T.


    An improvement in nuclear reactor shielding of a type used in reactor applications involving significant amounts of fast neutron flux, the reactor shielding including means providing structural support, neutron moderator material, neutron absorber material and other components as described below, wherein at least a portion of the neutron moderator material is magnesium in the form of magnesium oxide either alone or in combination with other moderator materials such as graphite and iron.

  18. Fuel handling apparatus for a nuclear reactor (United States)

    Hawke, Basil C.


    Fuel handling apparatus for transporting fuel elements into and out of a nuclear reactor and transporting them within the reactor vessel extends through a penetration in the side of the reactor vessel. A lateral transport device carries the fuel elements laterally within the vessel and through the opening in the side of the vessel, and a reversible lifting device raises and lowers the fuel elements. In the preferred embodiment, the lifting device is supported by a pair of pivot arms.


    Treshow, M.


    A boiling-water reactor is described in which the steam developed in the reactor is superheated in the reactor. This is accomplished by providing means for separating the steam from the water and passing the steam over a surface of the fissionable material which is not in contact with the water. Specifically water is boiled on the outside of tubular fuel elements and the steam is superheated on the inside of the fuel elements.

  20. Experimental Breeder Reactor I Preservation Plan

    Energy Technology Data Exchange (ETDEWEB)

    Julie Braun


    Experimental Breeder Reactor I (EBR I) is a National Historic Landmark located at the Idaho National Laboratory, a Department of Energy laboratory in southeastern Idaho. The facility is significant for its association and contributions to the development of nuclear reactor testing and development. This Plan includes a structural assessment of the interior and exterior of the EBR I Reactor Building from a preservation, rather than an engineering stand point and recommendations for maintenance to ensure its continued protection.

  1. Reactors are indispensable for radioisotope production. (United States)

    Mushtaq, Ahmad


    Radioisotopes can be produced by reactors and accelerators. For certain isotopes there could be an advantage to a certain production method. However, nowadays many reports suggest, that useful isotopes needed in medicine, industry and research could be produced efficiently and dependence on reactors using enriched U-235 may be eliminated. In my view reactors and accelerators will continue to play their role side by side in the supply of suitable and economical sources of isotopes.

  2. Education and Training on ISIS Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Foulon, F.; Badeau, G.; Lescop, B.; Wohleber, X. [French Atomic Energy and Alternative Energies Commission, Paris (France)


    In the frame of academic and vocational programs the National Institute for Nuclear Science and Technology uses the ISIS research reactor as a major tool to ensure a practical and comprehensive understanding of the nuclear reactor physics, principles and operation. A large set of training courses have been developed on ISIS, optimising both the content of the courses and the pedagogical approach. Programs with duration ranging from 3 hours (introduction to reactor operation) to 24 hours (full program for the future operators of research reactors) are carried out on ISIS reactor. The reactor is operated about 350 hours/year for education and training, about 40 % of the courses being carried out in English. Thus, every year about 400 trainees attend training courses on ISIS reactor. We present here the ISIS research reactor and the practical courses that have been developed on ISIS reactor. Emphasis is given to the pedagogical method which is used to focus on the operational and safety aspects, both in normal and incidental operation. We will present the curricula of the academic and vocational courses in which the practical courses are integrated, the courses being targeted to a wide public, including operators of research reactors, engineers involved in the design and operation of nuclear reactors as well as staff of the regulatory body. We address the very positive impact of the courses on the development of the competences and skills of participants. Finally, we describe the Internet Reactor Laboratories (IRL) that are under development and will consist in broadcasting the training courses via internet to remote facilities or institutions.

  3. Initiating Events for Multi-Reactor Plant Sites

    Energy Technology Data Exchange (ETDEWEB)

    Muhlheim, Michael David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Flanagan, George F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Poore, III, Willis P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)


    Inherent in the design of modular reactors is the increased likelihood of events that initiate at a single reactor affecting another reactor. Because of the increased level of interactions between reactors, it is apparent that the Probabilistic Risk Assessments (PRAs) for modular reactor designs need to specifically address the increased interactions and dependencies.

  4. Neutron imaging on the VR-1 reactor (United States)

    Crha, J.; Sklenka, L.; Soltes, J.


    Training reactor VR-1 is a low power research reactor with maximal thermal power of 1 kW. The reactor is operated by the Faculty of Nuclear Science and Physical Engineering of the Czech Technical University in Prague. Due to its low power it suits as a tool for education of university students and training of professionals. In 2015, as part of student research project, neutron imaging was introduced as another type of reactor utilization. The low available neutron flux and the limiting spatial and construction capabilities of the reactor's radial channel led to the development of a special filter/collimator insertion inside the channel and choosing a nonstandard approach by placing a neutron imaging plate inside the channel. The paper describes preliminary experiments carried out on the VR-1 reactor which led to first radiographic images. It seems, that due to the reactor construction and low reactor power, the neutron imaging technique on the VR-1 reactor is feasible mainly for demonstration or educational and training purposes.

  5. Biofilm carrier migration model describes reactor performance. (United States)

    Boltz, Joshua P; Johnson, Bruce R; Takács, Imre; Daigger, Glen T; Morgenroth, Eberhard; Brockmann, Doris; Kovács, Róbert; Calhoun, Jason M; Choubert, Jean-Marc; Derlon, Nicolas


    The accuracy of a biofilm reactor model depends on the extent to which physical system conditions (particularly bulk-liquid hydrodynamics and their influence on biofilm dynamics) deviate from the ideal conditions upon which the model is based. It follows that an improved capacity to model a biofilm reactor does not necessarily rely on an improved biofilm model, but does rely on an improved mathematical description of the biofilm reactor and its components. Existing biofilm reactor models typically include a one-dimensional biofilm model, a process (biokinetic and stoichiometric) model, and a continuous flow stirred tank reactor (CFSTR) mass balance that [when organizing CFSTRs in series] creates a pseudo two-dimensional (2-D) model of bulk-liquid hydrodynamics approaching plug flow. In such a biofilm reactor model, the user-defined biofilm area is specified for each CFSTR; thereby, Xcarrier does not exit the boundaries of the CFSTR to which they are assigned or exchange boundaries with other CFSTRs in the series. The error introduced by this pseudo 2-D biofilm reactor modeling approach may adversely affect model results and limit model-user capacity to accurately calibrate a model. This paper presents a new sub-model that describes the migration of Xcarrier and associated biofilms, and evaluates the impact that Xcarrier migration and axial dispersion has on simulated system performance. Relevance of the new biofilm reactor model to engineering situations is discussed by applying it to known biofilm reactor types and operational conditions.

  6. Autonomous Control of Space Nuclear Reactors Project (United States)

    National Aeronautics and Space Administration — Nuclear reactors to support future robotic and manned missions impose new and innovative technological requirements for their control and protection instrumentation....

  7. Non-equilibrium radiation nuclear reactor (United States)

    Thom, K.; Schneider, R. T. (Inventor)


    An externally moderated thermal nuclear reactor is disclosed which is designed to provide output power in the form of electromagnetic radiation. The reactor is a gaseous fueled nuclear cavity reactor device which can operate over wide ranges of temperature and pressure, and which includes the capability of processing and recycling waste products such as long-lived transuranium actinides. The primary output of the device may be in the form of coherent radiation, so that the reactor may be utilized as a self-critical nuclear pumped laser.

  8. Advanced nuclear reactor types and technologies

    Energy Technology Data Exchange (ETDEWEB)

    Ignatiev, V. [ed.; Feinberg, O.; Morozov, A. [Russian Research Centre `Kurchatov Institute`, Moscow (Russian Federation); Devell, L. [Studsvik Eco and Safety AB, Nykoeping (Sweden)


    The document is a comprehensive world-wide catalogue of concepts and designs of advanced fission reactor types and fuel cycle technologies. Two parts have been prepared: Part 1 Reactors for Power Production and Part 2 Heating and Other Reactor Applications. Part 3, which will cover advanced waste management technology, reprocessing and disposal for different nuclear fission options is planned for compilation during 1995. The catalogue was prepared according to a special format which briefly presents the project title, technical approach, development status, application of the technology, reactor type, power output, and organization which developed these designs. Part 1 and 2 cover water cooled reactors, liquid metal fast reactors, gas-cooled reactors and molten salt reactors. Subcritical accelerator-driven systems are also considered. Various reactor applications as power production, heat generation, ship propulsion, space power sources and transmutation of such waste are included. Each project is described within a few pages with the main features of an actual design using a table with main technical data and figure as well as references for additional information. Each chapter starts with an introduction which briefly describes main trends and approaches in this field. Explanations of terms and abbreviations are provided in a glossary.

  9. Phosphorus removal in aerated stirred tank reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ghigliazza, R.; Lodi, A.; Rovatti, M. [Inst. of Chemical and Process Engineering ``G.B. Bonino``, Univ. of Genoa (Italy)


    The possibility to obtain biological phosphorus removal in strictly aerobic conditions has been investigated. Experiments, carried out in a continuous stirred tank reactor (CSTR), show the feasibility to obtain phosphorus removal without the anaerobic phase. Reactor performance in terms of phosphorus abatement kept always higher then 65% depending on adopted sludge retention time (SRT). In fact increasing SRT from 5 days to 8 days phosphorus removal and reactor performance increase but overcoming this SRT value a decreasing in reactor efficiency was recorded. (orig.) With 6 figs., 3 tabs., 18 refs.

  10. Nanostructured Catalytic Reactors for Air Purification Project (United States)

    National Aeronautics and Space Administration — This SBIR Phase I project proposes the development of lightweight compact nanostructured catalytic reactors for air purification from toxic gaseous organic...

  11. Nanostructured Catalytic Reactors for Air Purification Project (United States)

    National Aeronautics and Space Administration — This SBIR Phase II project proposes the development of lightweight compact nanostructured catalytic reactors for air purification from toxic gaseous organic...

  12. Microchannel Methanation Reactors Using Nanofabricated Catalysts Project (United States)

    National Aeronautics and Space Administration — Makel Engineering, Inc. (MEI) and the Pennsylvania State University (Penn State) propose to develop and demonstrate a microchannel methanation reactor based on...

  13. High Performance Photocatalytic Oxidation Reactor System Project (United States)

    National Aeronautics and Space Administration — Pioneer Astronautics proposes a technology program for the development of an innovative photocatalytic oxidation reactor for the removal and mineralization of...

  14. Supercritical-pressure light water cooled reactors

    CERN Document Server

    Oka, Yoshiaki


    This book focuses on the latest reactor concepts, single pass core and experimental findings in thermal hydraulics, materials, corrosion, and water chemistry. It highlights research on supercritical-pressure light water cooled reactors (SCWRs), one of the Generation IV reactors that are studied around the world. This book includes cladding material development and experimental findings on heat transfer, corrosion and water chemistry. The work presented here will help readers to understand the fundamental elements of reactor design and analysis methods, thermal hydraulics, materials and water

  15. Advances in light water reactor technologies

    CERN Document Server

    Saito, Takehiko; Ishiwatari, Yuki; Oka, Yoshiaki


    ""Advances in Light Water Reactor Technologies"" focuses on the design and analysis of advanced nuclear power reactors. This volume provides readers with thorough descriptions of the general characteristics of various advanced light water reactors currently being developed worldwide. Safety, design, development and maintenance of these reactors is the main focus, with key technologies like full MOX core design, next-generation digital I&C systems and seismic design and evaluation described at length. This book is ideal for researchers and engineers working in nuclear power that are interested


    Young, G.J.


    The method and means for controlling the neutron density in a nuclear reactor is described. It describes the method and means for flattening the neutron density distribution curve across the reactor by spacing the absorbing control members to varying depths in the central region closer to the center than to the periphery of the active portion of the reactor to provide a smaller neutron reproduction ratio in the region wherein the members are inserted, than in the remainder of the reactor thereby increasing the over-all potential power output.

  17. Sodium fast reactors with closed fuel cycle

    CERN Document Server

    Raj, Baldev; Vasudeva Rao, PR 0


    Sodium Fast Reactors with Closed Fuel Cycle delivers a detailed discussion of an important technology that is being harnessed for commercial energy production in many parts of the world. Presenting the state of the art of sodium-cooled fast reactors with closed fuel cycles, this book:Offers in-depth coverage of reactor physics, materials, design, safety analysis, validations, engineering, construction, and commissioning aspectsFeatures a special chapter on allied sciences to highlight advanced reactor core materials, specialized manufacturing technologies, chemical sensors, in-service inspecti

  18. Heat dissipating nuclear reactor with metal liner (United States)

    Gluekler, E.L.; Hunsbedt, A.; Lazarus, J.D.


    A nuclear reactor containment including a reactor vessel disposed within a cavity with capability for complete inherent decay heat removal in the earth and surrounded by a cast steel containment member which surrounds the vessel is described in this disclosure. The member has a thick basemat in contact with metal pilings. The basemat rests on a bed of porous particulate material, into which water is fed to produce steam which is vented to the atmosphere. There is a gap between the reactor vessel and the steel containment member. The containment member holds any sodium or core debris escaping from the reactor vessel if the core melts and breaches the vessel.

  19. Reactors for nuclear electric propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Buden, D.; Angelo, J.A. Jr.


    Propulsion is the key to space exploitation and power is the key to propulsion. This paper examines the role of nuclear fission reactors as the primary power source for high specific impulse electric propulsion systems for space missions of the 1980s and 1990s. Particular mission applications include transfer to and a reusable orbital transfer vehicle from low-Earth orbit to geosynchronous orbit, outer planet exploration and reconnaissance missions, and as a versatile space tug supporting lunar resource development. Nuclear electric propulsion is examined as an indispensable component in space activities of the next two decades.


    Petrick, M.


    A boiling-water reactor is described which has vertical fuel-containing channels for forming steam from water. Risers above the channels increase the head of water radially outward, whereby water is moved upward through the channels with greater force. The risers are concentric and the radial width of the space between them is somewhat small. There is a relatively low rate of flow of water up through the radially outer fuel-containing channels, with which the space between the risers is in communication. (AE C)

  1. Synfuel production in nuclear reactors (United States)

    Henning, C.D.

    Apparatus and method for producing synthetic fuels and synthetic fuel components by using a neutron source as the energy source, such as a fusion reactor. Neutron absorbers are disposed inside a reaction pipe and are heated by capturing neutrons from the neutron source. Synthetic fuel feedstock is then placed into contact with the heated neutron absorbers. The feedstock is heated and dissociates into its constituent synfuel components, or alternatively is at least preheated sufficiently to use in a subsequent electrolysis process to produce synthetic fuels and synthetic fuel components.

  2. Estimation of selected heavy metals and arsenic in PM10 aerosols in the ambient air of the Greater Athens Area, Greece. (United States)

    Vassilakos, Ch; Veros, D; Michopoulos, J; Maggos, Th; O'Connor, C M


    Aerosol samples of PM(10) were collected during summer and winter 2003 at two different sites in the Messogia Basin northeast of Athens, to demonstrate the variations of heavy metals in PM(10) and examine their relationship with both gaseous pollutants and meteorological parameters. Estimated heavy metals during the experimental campaign were mercury (Hg), cadmium (Cd), lead (Pb), nickel (Ni) and arsenic (As). The average heavy metal concentrations for the first site (Spata) constituted 0.66-14.7ng/m(3) for the summer period and 0.14-19.5ng/m(3) for the winter period. At the second site (Koropi), the corresponding values varied between 0.89 and 13.3ng/m(3) and 0.16 and 24.7ng/m(3), respectively. PM(10) Hg, PM(10) Cd and PM(10) Ni contents showed regular daily variations, with higher mass percentages during the summer, indicating differences in local PM(10) sources for each season. On the contrary, PM(10) Pb presented higher mass percentages during the winter. Examination of the relationship between heavy metals and meteorological parameters indicated a higher correlation with temperature and relative humidity, especially for Pb. In addition, most of the heavy metals (apart from Hg) presented an expected correlation with nitrate oxides (NO(x)), PM(10) and ozone (O(3)). Higher correlations with both meteorological parameters and gaseous pollutants were observed during the winter experimental campaign. Maximum heavy metal concentrations at both sites were observed during days with NE or NNE prevailing winds during the summer campaign, while the winter period was characterized with maximums during days with W or WNW prevailing winds.

  3. Modelling effects of chemical exposure on birds wintering in agricultural landscapes: The western burrowing owl (Athene cunicularia hypugaea) as a case study (United States)

    Engelman, Catherine A.; Grant, William E.; Mora, Miguel A.; Woodin, Marc


    We describe an ecotoxicological model that simulates the sublethal and lethal effects of chronic, low-level, chemical exposure on birds wintering in agricultural landscapes. Previous models estimating the impact on wildlife of chemicals used in agro-ecosystems typically have not included the variety of pathways, including both dermal and oral, by which individuals are exposed. The present model contains four submodels simulating (1) foraging behavior of individual birds, (2) chemical applications to crops, (3) transfers of chemicals among soil, insects, and small mammals, and (4) transfers of chemicals to birds via ingestion and dermal exposure. We demonstrate use of the model by simulating the impacts of a variety of commonly used herbicides, insecticides, growth regulators, and defoliants on western burrowing owls (Athene cunicularia hypugaea) that winter in agricultural landscapes in southern Texas, United States. The model generated reasonable movement patterns for each chemical through soil, water, insects, and rodents, as well as into the owl via consumption and dermal absorption. Sensitivity analysis suggested model predictions were sensitive to uncertainty associated with estimates of chemical half-lives in birds, soil, and prey, sensitive to parameters associated with estimating dermal exposure, and relatively insensitive to uncertainty associated with details of chemical application procedures (timing of application, amount of drift). Nonetheless, the general trends in chemical accumulations and the relative impacts of the various chemicals were robust to these parameter changes. Simulation results suggested that insecticides posed a greater potential risk to owls of both sublethal and lethal effects than do herbicides, defoliants, and growth regulators under crop scenarios typical of southern Texas, and that use of multiple indicators, or endpoints provided a more accurate assessment of risk due to agricultural chemical exposure. The model should prove

  4. Molecular Tracing of the Geographical Origin of Human Immunodeficiency Virus Type 1 Infection and Patterns of Epidemic Spread Among Migrants Who Inject Drugs in Athens. (United States)

    Paraskevis, Dimitrios; Kostaki, Evangelia; Nikolopoulos, Georgios K; Sypsa, Vana; Psichogiou, Mina; Del Amo, Julia; Hodges-Mameletzis, Ioannis; Paraskeva, Dimitra; Skoutelis, Athanasios; Malliori, Meni; Williams, Leslie; Friedman, Samuel R; Daikos, Georgios L; Hatzakis, Angelos


    High numbers of human immunodeficiency virus type 1 (HIV-1) infections among people who inject drugs (PWID) have been diagnosed in Athens, Greece, since 2011. We aimed to trace the geographic origin of HIV-1 infection for migrants who inject drugs and to investigate whether transmissions occur more frequently among migrants than among Greek nationals. Multiple cross-sectional studies were pooled to assemble all persons diagnosed with HIV-1 in Greece between 1 January 2011 and 31 October 2014. Phylogenetic analyses used maximum likelihood estimation. The hypothesis of ethnic compartmentalization was tested by reconstructing ancestral states of characters at the tips using the criterion of parsimony over a set of bootstrap trees. Of 2274 persons, 38.4% were PWID. Phylogenetic analyses showed the existence of 4 major PWID-specific local transmission networks (LTNs): CRF14_BG (437 [58.6%]), CRF35_AD (139 [18.6%]), subtype B (116 [15.6%]), and subtype A (54 [7.2%]). Of 184 non-Greek PWID, 78.3% had been infected within the PWID-LTNs. For 173 (94.3%), the origin of their infection was assumed to be in Greece (postmigration). For PWID infected within LTNs, transmissions for subtype A and CRF14_BG occurred more frequently among migrants than would be expected by chance (phyloethnic study). Our analysis showed that the majority of infections among migrants occurred postmigration. The existence of significant transmission networking among migrants highlights that this population is a priority for HIV prevention. As molecular analysis can estimate the probable country of HIV infection, it can help to inform the design of public health strategies.

  5. Aerosol Optical Depth as a Measure of Particulate Exposure Using Imputed Censored Data, and Relationship with Childhood Asthma Hospital Admissions for 2004 in Athens, Greece

    Directory of Open Access Journals (Sweden)

    Gary Higgs


    Full Text Available An understanding of human health implications from atmosphere exposure is a priority in both the geographic and the public health domains. The unique properties of geographic tools for remote sensing of the atmosphere offer a distinct ability to characterize and model aerosols in the urban atmosphere for evaluation of impacts on health. Asthma, as a manifestation of upper respiratory disease prevalence, is a good example of the potential interface of geographic and public health interests. The current study focused on Athens, Greece during the year of 2004 and (1 demonstrates a systemized process for aligning data obtained from satellite aerosol optical depth (AOD with geographic location and time, (2 evaluates the ability to apply imputation methods to censored data, and (3 explores whether AOD data can be used satisfactorily to investigate the association between AOD and health impacts using an example of hospital admission for childhood asthma. This work demonstrates the ability to apply remote sensing data in the evaluation of health outcomes, that the alignment process for remote sensing data is readily feasible, and that missing data can be imputed with a sufficient degree of reliability to develop complete datasets. Individual variables demonstrated small but significant effect levels on hospital admission of children for AOD, nitrogen oxides (NO x , relative humidity (rH, temperature, smoke, and inversely for ozone. However, when applying a multivari-able model, an association with asthma hospital admissions and air quality could not be demonstrated. This work is promising and will be expanded to include additional years.

  6. Aspirin Versus Clopidogrel for Type 2 Diabetic Patients with First-Ever Noncardioembolic Acute Ischemic Stroke: Ten-Year Survival Data from the Athens Stroke Outcome Project. (United States)

    Milionis, Haralampos; Ntaios, George; Papavasileiou, Vasileios; Spengos, Konstantinos; Manios, Efstathios; Elisaf, Moses; Vemmos, Konstantinos


    Diabetes mellitus is associated with an increased risk of stroke and poor outcome following a stroke event. We assessed the impact of discharge treatment with aspirin versus clopidogrel on the 10-year survival of patients with type 2 diabetes after a first-ever noncardioembolic acute ischemic stroke (AIS). This was a post hoc analysis of the Athens Stroke Outcome Project. Study outcomes included death, stroke recurrence, and a composite cardiovascular disease (CVD) end point (recurrent stroke, myocardial infarction, unstable angina, coronary revascularization, aortic aneurysm rupture, or sudden death). Kaplan-Meier survival curve and Cox regression analyses were performed. A total of 304 (93 women) diabetic patients receiving either aspirin (n = 197) or clopidogrel (n = 107) were studied. The 10-year survival was better in clopidogrel-treated patients than in aspirin-treated patients (19 deaths [17.7%] for clopidogrel versus 55 deaths [27.9%] for aspirin; log-rank test: 4.91, P = .027). Similarly, clopidogrel was associated with a favorable impact on recurrent stroke (12 events [11.2%] for clopidogrel versus 39 events [19.7%] for aspirin; log-rank test: 4.46, P = .035) and on the composite CVD end point (21 events [19.6%] for clopidogrel versus 54 events [27.4%] for aspirin; log-rank test: 4.17, P = .041). In the multivariable analysis, the beneficial effect of clopidogrel over aspirin on both primary and secondary end points was independent of age, gender, the presence of CVD or CVD risk factors, and stroke severity. Our findings indicate a favorable effect of clopidogrel at discharge compared with aspirin in preventing death, recurrent stroke, and CVD events in diabetic patients with a first-ever noncardioembolic AIS. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  7. Autonomous Control of Space Nuclear Reactors (United States)

    Merk, John


    Nuclear reactors to support future robotic and manned missions impose new and innovative technological requirements for their control and protection instrumentation. Long-duration surface missions necessitate reliable autonomous operation, and manned missions impose added requirements for failsafe reactor protection. There is a need for an advanced instrumentation and control system for space-nuclear reactors that addresses both aspects of autonomous operation and safety. The Reactor Instrumentation and Control System (RICS) consists of two functionally independent systems: the Reactor Protection System (RPS) and the Supervision and Control System (SCS). Through these two systems, the RICS both supervises and controls a nuclear reactor during normal operational states, as well as monitors the operation of the reactor and, upon sensing a system anomaly, automatically takes the appropriate actions to prevent an unsafe or potentially unsafe condition from occurring. The RPS encompasses all electrical and mechanical devices and circuitry, from sensors to actuation device output terminals. The SCS contains a comprehensive data acquisition system to measure continuously different groups of variables consisting of primary measurement elements, transmitters, or conditioning modules. These reactor control variables can be categorized into two groups: those directly related to the behavior of the core (known as nuclear variables) and those related to secondary systems (known as process variables). Reliable closed-loop reactor control is achieved by processing the acquired variables and actuating the appropriate device drivers to maintain the reactor in a safe operating state. The SCS must prevent a deviation from the reactor nominal conditions by managing limitation functions in order to avoid RPS actions. The RICS has four identical redundancies that comply with physical separation, electrical isolation, and functional independence. This architecture complies with the

  8. Investigation of molten salt fast breeder reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kubota, Kenichi; Enuma, Yasuhiro; Tanaka, Yoshihiko; Konomura, Mamoru; Ichimiya, Masakazu [Japan Nuclear Cycle Development Inst., Oarai, Ibaraki (Japan). Oarai Engineering Center


    Phase I of Feasibility Studies on Commercialized Fast Reactor System is being performed for two years from Japanese Fiscal Year 1999. In this report, results of the study on fluid fuel reactors (especially a molten salt fast breeder reactor concept) are described from the viewpoint of technical and economical concerns of the plant system design. In JFY1999, we have started to investigate the fluid fuel reactors as alternative concepts of sodium cooled FBR systems with MOX fuel, and selected the unique concept of a molten chloride fast breeder reactor, whose U-Pu fuel cycle can be related to both light water reactors and fast breeder reactors on the basis of present technical data and design experiences. We selected a preliminary composition of molten fuel and conceptual plant design through evaluation of technical and economical issues essential for the molten salt reactors and then compared them with reference design concepts of sodium cooled FBR systems under limited information on the molten chloride fast breeder reactors. The following results were obtained. (1) The molten chloride fast breeder reactors have inherent safety features in the core and plant performances, ad the fluid fuel is quite promising for cost reduction of the fuel fabrication and reprocessing. (2) On the other hand, the inventory of the molten chloride fuel becomes high and thermal conductivity of the coolant is inferior compared to those of sodium cooled FBR systems, then, the size of main components such as IHX's becomes larger and the amount of construction materials is seems to be increased. (3) Furthermore economical vessel and piping materials which contact with the molten chloride salts are required to be developed. From the results, it is concluded that further steps to investigate the molten chloride fast breeder reactor concepts are too early to be conducted. (author)

  9. K-East and K-West Reactors (United States)

    Federal Laboratory Consortium — Hanford's "sister reactors", the K-East and the K-West Reactors, were built side-by-side in the early 1950's. The two reactors went operational within four months of...

  10. Simulated nuclear reactor fuel assembly (United States)

    Berta, Victor T.


    An apparatus for electrically simulating a nuclear reactor fuel assembly. It includes a heater assembly having a top end and a bottom end and a plurality of concentric heater tubes having electrical circuitry connected to a power source, and radially spaced from each other. An outer target tube and an inner target tube is concentric with the heater tubes and with each other, and the outer target tube surrounds and is radially spaced from the heater tubes. The inner target tube is surrounded by and radially spaced from the heater tubes and outer target tube. The top of the assembly is generally open to allow for the electrical power connection to the heater tubes, and the bottom of the assembly includes means for completing the electrical circuitry in the heater tubes to provide electrical resistance heating to simulate the power profile in a nuclear reactor. The embedded conductor elements in each heater tube is split into two halves for a substantial portion of its length and provided with electrical isolation such that each half of the conductor is joined at one end and is not joined at the other end.

  11. Dissecting Reactor Antineutrino Flux Calculations (United States)

    Sonzogni, A. A.; McCutchan, E. A.; Hayes, A. C.


    Current predictions for the antineutrino yield and spectra from a nuclear reactor rely on the experimental electron spectra from 235U, 239Pu, 241Pu and a numerical method to convert these aggregate electron spectra into their corresponding antineutrino ones. In the present work we investigate quantitatively some of the basic assumptions and approximations used in the conversion method, studying first the compatibility between two recent approaches for calculating electron and antineutrino spectra. We then explore different possibilities for the disagreement between the measured Daya Bay and the Huber-Mueller antineutrino spectra, including the 238U contribution as well as the effective charge and the allowed shape assumption used in the conversion method. We observe that including a shape correction of about +6 % MeV-1 in conversion calculations can better describe the Daya Bay spectrum. Because of a lack of experimental data, this correction cannot be ruled out, concluding that in order to confirm the existence of the reactor neutrino anomaly, or even quantify it, precisely measured electron spectra for about 50 relevant fission products are needed. With the advent of new rare ion facilities, the measurement of shape factors for these nuclides, for many of which precise beta intensity data from TAGS experiments already exist, would be highly desirable.

  12. New Production Reactors Program Plan

    Energy Technology Data Exchange (ETDEWEB)


    Part I of this New Production Reactors (NPR) Program Plan: describes the policy basis of the NPR Program; describes the mission and objectives of the NPR Program; identifies the requirements that must be met in order to achieve the mission and objectives; and describes and assesses the technology and siting options that were considered, the Program's preferred strategy, and its rationale. The implementation strategy for the New Production Reactors Program has three functions: Linking the design, construction, operation, and maintenance of facilities to policies requirements, and the process for selecting options. The development of an implementation strategy ensures that activities and procedures are consistent with the rationale and analysis underlying the Program. Organization of the Program. The strategy establishes plans, organizational structure, procedures, a budget, and a schedule for carrying out the Program. By doing so, the strategy ensures the clear assignment of responsibility and accountability. Management and monitoring of the Program. Finally, the strategy provides a basis for monitoring the Program so that technological, cost, and scheduling issues can be addressed when they arise as the Program proceeds. Like the rest of the Program Plan, the Implementation Strategy is a living document and will be periodically revised to reflect both progress made in the Program and adjustments in plans and policies as they are made. 21 figs., 5 tabs.

  13. Research on plasma core reactors (United States)

    Jarvis, G. A.; Barton, D. M.; Helmick, H. H.; Bernard, W.; White, R. H.


    Experiments and theoretical studies are being conducted for NASA on critical assemblies with one-meter diameter by one-meter long low-density cores surrounded by a thick beryllium reflector. These assemblies make extensive use of existing nuclear propulsion reactor components, facilities, and instrumentation. Due to excessive porosity in the reflector, the initial critical mass was 19 kg U(93.2). Addition of a 17 cm thick by 89 cm diameter beryllium flux trap in the cavity reduced the critical mass to 7 kg when all the uranium was in the zone just outside the flux trap. A mockup aluminum UF6 container was placed inside the flux trap and fueled with uranium-graphite elements. Fission distributions and reactivity worths of fuel and structural materials were measured. Finally, an 85,000 cu cm aluminum canister in the central region was fueled with UF6 gas and fission density distributions determined. These results are to be used to guide the design of a prototype plasma core reactor which will test energy removal by optical radiation.

  14. A next-generation reactor concept: The Integral Fast Reactor (IFR)

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Y.I.


    The Integral Fast Reactor (IFR) is an advanced liquid metal reactor concept being developed at Argonne National Laboratory as reactor technology for the 21st century. It seeks to specifically exploit the inherent properties of liquid metal cooling and metallic fuel in a way that leads to substantial improvements in the characteristics of the complete reactor system, in particular passive safety and waste management. The IFR concept consists of four technical features: (1) liquid sodium cooling, (2) pool-type reactor configuration, (3) metallic fuel, and (4) fuel cycle closure based on pyroprocessing.

  15. A next-generation reactor concept: The Integral Fast Reactor (IFR)

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Y.I.


    The Integral Fast Reactor (IFR) is an advanced liquid metal reactor concept being developed at Argonne National Laboratory as reactor technology for the 21st century. It seeks to specifically exploit the inherent properties of liquid metal cooling and metallic fuel in a way that leads to substantial improvements in the characteristics of the complete reactor system, in particular passive safety and waste management. The IFR concept consists of four technical features: (1) liquid sodium cooling, (2) pool-type reactor configuration, (3) metallic fuel, and (4) fuel cycle closure based on pyroprocessing.

  16. A new MTR fuel for a new MTR reactor: UMo for the Jules Horowitz reactor

    Energy Technology Data Exchange (ETDEWEB)

    Guigon, B. [CEA Cadarache, Dir. de l' Energie Nucleaire DEN, Reacteur Jules Horowitz, 13 - Saint-Paul-lez-Durance (France); Vacelet, H. [Compagnie pour l' Etude et la Realisation de Combustibles Atomiques, CERCA, Etablissement de Romans, 26 (France); Dornbusch, D. [Technicatome, Service d' Architecture Generale, 13 - Aix-en-Provence (France)


    Within some years, the Jules Horowitz Reactor will be the only working experimental reactor (material and fuel testing reactor) in France. It will have to provide facilities for a wide range of needs: from activation analysis to power reactor fuel qualification. In this paper will be presented the main characteristics of the Jules Horowitz Reactor: its total power, neutron flux, fuel element... Safety criteria will be explained. Finally merits and disadvantages of UMo compared to the standard U{sub 3}Si{sub 2} fuel will be discussed. (authors)

  17. Annual report on JEN-1 reactor; Informe periodico del Reactor JEN-1 correspondiente al ano 1971

    Energy Technology Data Exchange (ETDEWEB)

    Montes, J.


    In the annual report on the JEN-1 reactor the main features of the reactor operations and maintenance are described. The reactor has been critical for 1831 hours, what means 65,8% of the total working time. Maintenance and pool water contamination have occupied the rest of the time. The maintenance schedule is shown in detail according to three subjects. The main failures and reactor scrams are also described. The daily maximum values of the water activity are given so as the activity of the air in the reactor hall. (Author)

  18. Design of an Organic Simplified Nuclear Reactor

    Directory of Open Access Journals (Sweden)

    Koroush Shirvan


    Full Text Available Numerous advanced reactor concepts have been proposed to replace light water reactors ever since their establishment as the dominant technology for nuclear energy production. While most designs seek to improve cost competitiveness and safety, the implausibility of doing so with affordable materials or existing nuclear fuel infrastructure reduces the possibility of near-term deployment, especially in developing countries. The organic nuclear concept, first explored in the 1950s, offers an attractive alternative to advanced reactor designs being considered. The advent of high temperature fluids, along with advances in hydrocracking and reforming technologies driven by the oil and gas industries, make the organic concept even more viable today. We present a simple, cost-effective, and safe small modular nuclear reactor for offshore underwater deployment. The core is moderated by graphite, zirconium hydride, and organic fluid while cooled by the organic fluid. The organic coolant enables operation near atmospheric pressure and use of plain carbon steel for the reactor tank and primary coolant piping system. The core is designed to mitigate the coolant degradation seen in early organic reactors. Overall, the design provides a power density of 40 kW/L, while reducing the reactor hull size by 40% compared with a pressurized water reactor while significantly reducing capital plant costs.

  19. Monolithic reactor : Higher yield, less energy

    NARCIS (Netherlands)

    Kreutzer, M.T.; Moulijn, J.A.; Kapteijn, F.; Mols, B.


    The production of margarine, the desulphurisation of crude oil, and the manufacture of synthetic diesel fuel, these are only three of the many industrial processes in which a three-phase reactor is used. Traditionally, this type of reactor is rather ill-defined. Success with a lab scale set-up is no


    Balent, R.


    This patent describes a method of obtaining a flatter flux and more uniform power generation across the core of a nuclear reactor. The method comprises using moderator elements having differing moderating strength. The elements have an increasing amount of the better moderating material as a function of radial and/or axial distance from the reactor core center. (AEC)

  1. Reactor antineutrino spectra and forbidden beta decays (United States)

    Štefánik, Dušan; Dvornický, Rastislav; Šimkovic, Fedor


    The exact relativistic shape factors, associated with the nuclear matrix elements governing the first forbidden beta decays, are presented. It is expected that their consideration can allow a more accurate theoretical description of antineutrino fluxes from the power reactor. A qualitative analysis of the uncertainty of reactor antineutrino flux from 235U within the electron spectrum conversion method is performed.

  2. Helium-cooled high temperature reactors

    Energy Technology Data Exchange (ETDEWEB)

    Trauger, D.B.


    Experience with several helium cooled reactors has been favorable, and two commercial plants are now operating. Both of these units are of the High Temperature Graphite Gas Cooled concept, one in the United States and the other in the Federal Republic of Germany. The initial helium charge for a reactor of the 1000 MW(e) size is modest, approx.15,000 kg.

  3. Rotor for a pyrolysis centrifuge reactor

    DEFF Research Database (Denmark)


    The present invention relates to a rotor for a pyrolysis centrifuge reactor, said rotor comprising a rotor body having a longitudinal centre axis, and at least one pivotally mounted blade being adapted to pivot around a pivot axis under rotation of the rotor body around the longitudinal centre axis....... Moreover, the present invention relates to a pyrolysis centrifuge reactor applying such a rotor....

  4. The Design of a Nuclear Reactor

    Indian Academy of Sciences (India)

    IAS Admin

    The aim of this largely pedagogical article is to employ pre-college physics to arrive at an un- derstanding of a system as complex as a nuclear reactor. We focus on three key issues: the fuel pin, the moderator, and lastly the dimensions of the nuclear reactor. 1. Introduction. Design considerations have engaged human ...

  5. Advances in Tandem Mirror fusion power reactors

    Energy Technology Data Exchange (ETDEWEB)

    Perkins, L.J.; Logan, B.G.


    The Tandem Mirror exhibits several distinctive features which make the reactor embodiment of the principle very attractive: Simple low-technology linear central cell; steady-state operation; high-..beta.. operation; no driven current or disruptions; divertorless operation; direction conversion of end-loss power; low-surface heat loads; and advanced fusion fuel capability. In this paper, we examine these features in connection with two tandem mirror reactor designs, MARS and MINIMARS, and several advanced reactor concepts including the wall-stabilized reactor and the field-reversed mirror. With a novel compact end plug scheme employing octopole stabilization, MINIMARS is expressly designed for short construction times, factory-built modules, and a small (600 MWe) but economic reactor size. We have also configured the design for low radioactive afterheat and inherent/passive safety under LOCA/LOFA conditions, thereby obviating the need for expensive engineered safety systems. In contrast to the complex and expensive double-quadrupole end-cell of the MARS reactor, the compact octopole end-cell of MINIMARS enables ignition to be achieved with much shorter central cell lengths and considerably improves the economy of scale for small (approx.250 to 600 MWe) tandem mirror reactors. Finally, we examine the prospects for realizing the ultimate potential of the tandem mirror with regard to both innovative configurations and novel neutron energy conversion schemes, and stress that advanced fuel applications could exploit its unique reactor features.

  6. Selective purge for hydrogenation reactor recycle loop (United States)

    Baker, Richard W.; Lokhandwala, Kaaeid A.


    Processes and apparatus for providing improved contaminant removal and hydrogen recovery in hydrogenation reactors, particularly in refineries and petrochemical plants. The improved contaminant removal is achieved by selective purging, by passing gases in the hydrogenation reactor recycle loop or purge stream across membranes selective in favor of the contaminant over hydrogen.

  7. Utilisation of British University Research Reactors. (United States)

    Duncton, P. J.; And Others

    British experience relating to the employment of university research reactors and subcritical assemblies in the education of nuclear scientists and technologists, in the training of reactor operators and for fundamental pure and applied research in this field is reviewed. The facilities available in a number of British universities and the uses…

  8. The First Reactor, 40th Anniversary (rev.)

    Energy Technology Data Exchange (ETDEWEB)

    Allardice, Corbin; Trapnell, Edward R; Fermi, Enrico; Fermi, Laura; Williams, Robert C


    This booklet, an updated version of the original booklet describing the first nuclear reactor, was written in honor of the 40th anniversary of the first reactor or "pile". It is based on firsthand accounts told to Corbin Allardice and Edward R. Trapnell, and includes recollections of Enrico and Laura Fermi.

  9. Helix reactor: great potential for flow chemistry

    NARCIS (Netherlands)

    Geerdink, P.; Runstraat, A. van den; Roelands, C.P.M.; Goetheer, E.L.V.


    The Helix reactor is highly suited for precise reaction control based on good hydrodynamics. The hydrodynamics are controlled by the Dean vortices, which create excellent heat transfer properties, approach plug flow and avoid turbulence. The flexibility of this reactor has been demonstrated using a

  10. Verification of Remote Inspection Techniques for Reactor Internal Structures of Liquid Metal Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Young Sang; Lee, Jae Han


    The reactor internal structures and components of a liquid metal reactor (LMR) are submerged in hot sodium of reactor vessel. The division 3 of ASME code section XI specifies the visual inspection as major in-service inspection (ISI) methods of reactor internal structures and components. Reactor internals of LMR can not be visually examined due to opaque liquid sodium. The under-sodium viewing techniques using an ultrasonic wave should be applied for the visual inspection of reactor internals. Recently, an ultrasonic waveguide sensor with a strip plate has been developed for an application to the under-sodium inspection. In this study, visualization technique, ranging technique and monitoring technique have been suggested for the remote inspection of reactor internals by using the waveguide sensor. The feasibility of these remote inspection techniques using ultrasonic waveguide sensor has been evaluated by an experimental verification.

  11. Reactor core and plant design concepts of the Canadian supercritical water-cooled reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yetisir, M.; Gaudet, M.; Bailey, J.; Rhodes, D.; Guzonas, D.; Hamilton, H.; Haque, Z.; Pencer, J.; Sartipi, A. [Atomic Energy of Canada Limited, Chalk River, ON (Canada)


    Canada is developing a 1200 MWe supercritical water-cooled reactor (SCWR), which has evolved from the well-established pressure-tube type CANDU{sup 1} reactor. This SCWR reactor concept, which is often referred to as the Canadian SCWR, uses supercritical water as a coolant, has a low-pressure heavy water moderator and a direct cycle for power production. The reactor concept incorporates advanced safety features, such as passive emergency core cooling, long-term decay heat rejection to the environment and fuel melt prevention via passive moderator cooling. These features significantly reduce the core damage frequency beyond existing nuclear reactors. This paper presents a description of the Canadian SCWR core design concept, the integration of in-core and out-of-core components and the mechanical plant design concept. Supporting systems for reactor safety, reactor control and moderator cooling are also described. (author)

  12. Cooling system for a nuclear reactor (United States)

    Amtmann, Hans H.


    A cooling system for a gas-cooled nuclear reactor is disclosed which includes at least one primary cooling loop adapted to pass coolant gas from the reactor core and an associated steam generator through a duct system having a main circulator therein, and at least one auxiliary cooling loop having communication with the reactor core and adapted to selectively pass coolant gas through an auxiliary heat exchanger and circulator. The main and auxiliary circulators are installed in a common vertical cavity in the reactor vessel, and a common return duct communicates with the reactor core and intersects the common cavity at a junction at which is located a flow diverter valve operative to effect coolant flow through either the primary or auxiliary cooling loops.

  13. Slurry Bubble Column Reactor Optimization (book chapter)

    Energy Technology Data Exchange (ETDEWEB)

    Gamwo, I.K.; Gidaspow, D. (Illinois Inst. of Technology, Chicago, IL); Jung, J. (ANL)


    Slurry bubble column reactors (SBCR) are the preferred contactors for the conversion of syngas to fules and chemicals partially due to their superior heat and mass transfer characteristics. The multiphase fluid dynamics in these systems greatly affect the reactor volumetric productivity. Here, we have developed a computational fluid dynamics (CFD) assisted design methodology for searching the optimum particle size for maximum production in a SBCR. Reactor optimization due to heat exchanger configuration was also investigated. We have rearranged the heat exchangers in a SBCR and constructed a CFD model for a baffled reactor. The novel arrangement of the exchangers prevents the unfavorable high catalysts concentration at the lower stage of the reactor. Thus an optimum catalyst concentration is maintained during the course of the production of liquid fuels.

  14. Scanning tunneling microscope assembly, reactor, and system (United States)

    Tao, Feng; Salmeron, Miquel; Somorjai, Gabor A


    An embodiment of a scanning tunneling microscope (STM) reactor includes a pressure vessel, an STM assembly, and three spring coupling objects. The pressure vessel includes a sealable port, an interior, and an exterior. An embodiment of an STM system includes a vacuum chamber, an STM reactor, and three springs. The three springs couple the STM reactor to the vacuum chamber and are operable to suspend the scanning tunneling microscope reactor within the interior of the vacuum chamber during operation of the STM reactor. An embodiment of an STM assembly includes a coarse displacement arrangement, a piezoelectric fine displacement scanning tube coupled to the coarse displacement arrangement, and a receiver. The piezoelectric fine displacement scanning tube is coupled to the coarse displacement arrangement. The receiver is coupled to the piezoelectric scanning tube and is operable to receive a tip holder, and the tip holder is operable to receive a tip.

  15. Cleaning natural water in the clarifier reactor (United States)

    Skolubovich, Yuriy; Skolubovich, Aleksandr; Voitov, Evgeniy; Soppa, Mikhail; Chirkunov, Yuriy


    The problems of cleaning low turbidity high-color surface waters for drinking water supply are considered. A new design of the clarifier reactor is proposed, which increases the efficiency of water purification and at the same time reduces its operating costs. A detailed description of clarifier reactor design and its operation is given. The study results of the clarifier reactor operation in real conditions for the purification of low turbidity high-color waters are shown. Due to the weighted layer of dense loading use in a process of water purification, the structure productivity can be increased by 2-3 times in comparison with conventional clarifiers with suspended sediment. Using reagents for water purification, the clarifier reactor, due to the processes of contact coagulation, allows reducing the consumption of reagents up to 50%. Investigations of the clarifier reactor operation in technological schemes for various waters purification, including sewage, showed their effectiveness and prospects.

  16. Seismic attenuation system for a nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Liszkai, Tamas; Cadell, Seth


    A system for attenuating seismic forces includes a reactor pressure vessel containing nuclear fuel and a containment vessel that houses the reactor pressure vessel. Both the reactor pressure vessel and the containment vessel include a bottom head. Additionally, the system includes a base support to contact a support surface on which the containment vessel is positioned in a substantially vertical orientation. An attenuation device is located between the bottom head of the reactor pressure vessel and the bottom head of the containment vessel. Seismic forces that travel from the base support to the reactor pressure vessel via the containment vessel are attenuated by the attenuation device in a direction that is substantially lateral to the vertical orientation of the containment vessel.

  17. TRIGA research reactors; Reacteurs de recherche Triga

    Energy Technology Data Exchange (ETDEWEB)

    Fouquet, D.M.; Razvi, J.; Whittemore, W.L. [Triga General Atomics, San Diego, CA (United States); Duban, B.; Harbonnier, G.; Du Limbert, P.; Durand, J.P. [AREVA/FRAMATOME ANP/CERCA, 92 - Paris-La-Defence (France)


    TRIGA (Training, Research, Isotope production, General-Atomic) has become the most used research reactor in the world with 65 units operating in 24 countries. The original patent for TRIGA reactors was registered in 1958. The success of this reactor is due to its inherent level of safety that results from a prompt negative temperature coefficient. Most of the neutron moderation occurs in the nuclear fuel (UZrH) because of the presence of hydrogen atoms, so in case of an increase of fuel temperature, the neutron spectrum becomes harder and neutrons are less likely to fission uranium nuclei and as a consequence the power released decreases. This inherent level of safety has made this reactor fit for training tool in university laboratories. Some recent versions of TRIGA reactors have been designed for medicine and industrial isotope production, for neutron therapy of cancers and for providing a neutron source. (A.C.)

  18. Nuclear propulsion apparatus with alternate reactor segments (United States)

    Szekely, Thomas


    1. Nuclear propulsion apparatus comprising: A. means for compressing incoming air; B. nuclear fission reactor means for heating said air; C. means for expanding a portion of the heated air to drive said compressing means; D. said nuclear fission reactor means being divided into a plurality of radially extending segments; E. means for directing a portion of the compressed air for heating through alternate segments of said reactor means and another portion of the compressed air for heating through the remaining segments of said reactor means; and F. means for further expanding the heated air from said drive means and the remaining heated air from said reactor means through nozzle means to effect reactive thrust on said apparatus.

  19. Reactivity control assembly for nuclear reactor. [LMFBR (United States)

    Bollinger, L.R.


    This invention, which resulted from a contact with the United States Department of Energy, relates to a control mechanism for a nuclear reactor and, more particularly, to an assembly for selectively shifting different numbers of reactivity modifying rods into and out of the core of a nuclear reactor. It has been proposed heretofore to control the reactivity of a breeder reactor by varying the depth of insertion of control rods (e.g., rods containing a fertile material such as ThO/sub 2/) in the core of the reactor, thereby varying the amount of neutron-thermalizing coolant and the amount of neutron-capturing material in the core. This invention relates to a mechanism which can advantageously be used in this type of reactor control system.

  20. Estudo do nicho ecológico de duas aves de rapina (Falco sparverius e Athene cunicularia) em uma região de dunas do Rio Grande do Sul, Brasil


    Zilio, Felipe


    Duas espécies só podem coexistir durante um longo período de tempo se diferirem em alguns aspectos ecológicos. Essas são premissas do conceito de nicho ecológico de uma espécie. Falco sparverius e Athene cunicularia são aves de rapina de ocorrência comum na maioria da região neotropical. Usualmente encontradas em simpatria, ocorrem em ambientes abertos, com pouca vegetação e apresentam uma dieta similar, baseada em insetos, e comportamentos de caça semelhantes. Os ambientes costeiros do Rio G...

  1. The management of cornea blindness from severe corneal scarring, with the Athens Protocol (transepithelial topography-guided PRK therapeutic remodeling, combined with same-day, collagen cross-linking

    Directory of Open Access Journals (Sweden)

    Kanellopoulos AJ


    Full Text Available Anastasios John Institute, Athens, Greece; Manhattan Eye, Ear and Throat Hospital, New York, NY, USA; New York University Medical School, New York, NY, USAPurpose: To evaluate the safety and efficacy of combined transepithelial topography-guided photorefractive keratectomy (PRK therapeutic remodeling, combined with same-day, collagen cross-linking (CXL. This protocol was used for the management of cornea blindness due to severe corneal scarring.Methods: A 57-year-old man had severe corneal blindness in both eyes. Both corneas had significant central scars attributed to a firework explosion 45 years ago, when the patient was 12 years old. Corrected distance visual acuity (CDVA was 20/100 both eyes (OU with refraction: +4.00, –4.50 at 135° in the right eye and +3.50, –1.00 at 55° in the left. Respective keratometries were: 42.3, 60.4 at 17° and 35.8, 39.1 at 151.3°. Cornea transplantation was the recommendation by multiple cornea specialists as the treatment of choice. We decided prior to considering a transplant to employ the Athens Protocol (combined topography-guided partial PRK and CXL in the right eye in February 2010 and in the left eye in September 2010. The treatment plan for both eyes was designed on the topography-guided wavelight excimer laser platform.Results: Fifteen months after the right eye treatment, the right cornea had improved translucency and was topographically stable with uncorrected distance visual acuity (UDVA 20/50 and CDVA 20/40 with refraction +0.50, –2.00 at 5°. We noted a similar outcome after similar treatment applied in the left eye with UDVA 20/50 and CDVA 20/40 with –0.50, –2.00 at 170° at the 8-month follow-up.Conclusion: In this case, the introduction of successful management of severe cornea abnormalities and scarring with the Athens Protocol may provide an effective alternative to other existing surgical or medical options.Keywords: Athens Protocol, collagen cross

  2. Ceramic oxygen transport membrane array reactor and reforming method

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Sean M.; Christie, Gervase Maxwell; Robinson, Charles; Wilson, Jamie R.; Gonzalez, Javier E.; Doraswami, Uttam R.


    The invention relates to a commercially viable modular ceramic oxygen transport membrane reforming reactor configured using repeating assemblies of oxygen transport membrane tubes and catalytic reforming reactors.

  3. Fast Spectrum Molten Salt Reactor Options

    Energy Technology Data Exchange (ETDEWEB)

    Gehin, Jess C [ORNL; Holcomb, David Eugene [ORNL; Flanagan, George F [ORNL; Patton, Bruce W [ORNL; Howard, Rob L [ORNL; Harrison, Thomas J [ORNL


    During 2010, fast-spectrum molten-salt reactors (FS-MSRs) were selected as a transformational reactor concept for light-water reactor (LWR)-derived heavy actinide disposition by the Department of Energy-Nuclear Energy Advanced Reactor Concepts (ARC) program and were the subject of a preliminary scoping investigation. Much of the reactor description information presented in this report derives from the preliminary studies performed for the ARC project. This report, however, has a somewhat broader scope-providing a conceptual overview of the characteristics and design options for FS-MSRs. It does not present in-depth evaluation of any FS-MSR particular characteristic, but instead provides an overview of all of the major reactor system technologies and characteristics, including the technology developments since the end of major molten salt reactor (MSR) development efforts in the 1970s. This report first presents a historical overview of the FS-MSR technology and describes the innovative characteristics of an FS-MSR. Next, it provides an overview of possible reactor configurations. The following design features/options and performance considerations are described including: (1) reactor salt options-both chloride and fluoride salts; (2) the impact of changing the carrier salt and actinide concentration on conversion ratio; (3) the conversion ratio; (4) an overview of the fuel salt chemical processing; (5) potential power cycles and hydrogen production options; and (6) overview of the performance characteristics of FS-MSRs, including general comparative metrics with LWRs. The conceptual-level evaluation includes resource sustainability, proliferation resistance, economics, and safety. The report concludes with a description of the work necessary to begin more detailed evaluation of FS-MSRs as a realistic reactor and fuel cycle option.

  4. The research reactors their contribution to the reactors physics; Les reacteurs de recherche leur apport sur la physique des reacteurs

    Energy Technology Data Exchange (ETDEWEB)

    Barral, J.C. [Electricite de France (EDF), 75 - Paris (France); Zaetta, A. [CEA/Cadarache, Direction des Reacteurs Nucleaires, DRN, 13 - Saint-Paul-lez-Durance (France); Johner, J. [CEA/Cadarache, Dept. de Recherches sur la Fusion Controlee (DRFC), 13 - Saint Paul lez Durance (France); Mathoniere, G. [CEA/Saclay, DEN, 91 - Gif sur Yvette (France)] [and others


    The 19 october 2000, the french society of nuclear energy organized a day on the research reactors. This associated report of the technical session, reactors physics, is presented in two parts. The first part deals with the annual meeting and groups general papers on the pressurized water reactors, the fast neutrons reactors and the fusion reactors industry. The second part presents more technical papers about the research programs, critical models, irradiation reactors (OSIRIS and Jules Horowitz) and computing tools. (A.L.B.)

  5. Gas Reactor International Cooperative Program. Interim report. Construction and operating experience of selected European Gas-Cooled Reactors

    Energy Technology Data Exchange (ETDEWEB)


    The construction and operating experience of selected European Gas-Cooled Reactors is summarized along with technical descriptions of the plants. Included in the report are the AVR Experimental Pebble Bed Reactor, the Dragon Reactor, AGR Reactors, and the Thorium High Temperature Reactor (THTR). The study demonstrates that the European experience has been favorable and forms a good foundation for the development of Advanced High Temperature Reactors.

  6. Replacement reactor to revolutionise magnets

    CERN Document Server

    Atkins, G


    Electric motors, hearing aids and magnetic resonance imaging are only some of the applications that will benefit from the first advances in magnets in a quarter of a century. Magnets achieve their characteristics when electrons align themselves to produce a unified magnetic field. Neutrons can probe these magnetic structures. The focus is not just on making more powerful magnets, but also identifying the characteristics that make magnets cheaper and easier for industry to manufacture. Staff from the ANSTO's Neutron Scattering Group have already performed a number of studies on the properties of magnets using using HIFAR, but the Replacement Research Reactor that will produce cold neutrons would allow scientists to investigate the atomic properties of materials with large molecules. A suite of equipment will enable studies at different temperatures, pressures and magnetic fields

  7. Reactor operation environmental information document

    Energy Technology Data Exchange (ETDEWEB)

    Wike, L.D.; Specht, W.L.; Mackey, H.E.; Paller, M.H.; Wilde, E.W.; Dicks, A.S.


    The Savannah River Site (SRS) is a large United States Department of Energy installation on the upper Atlantic Coastal Plain of South Carolina. The SRS contains diverse habitats, flora, and fauna. Habitats include upland terrestrial areas, varied wetlands including Carolina Bays, the Savannah River swamp system, and impoundment related and riparian wetlands, and the aquatic habitats of several stream systems, two large cooling reservoirs, and the Savannah River. These diverse habitats support a large variety of plants and animals including many commercially or recreational valuable species and several rare, threatened or endangered species. This volume describes the major habitats and their biota found on the SRS, and discuss the impacts of continued operation of the K, L, and P production reactors.


    Bassett, C.H.


    A fuel element is designed which is particularly adapted for reactors of high power density used to generate steam for the production of electricity. The fuel element consists of inner and outer concentric tubes forming an annular chamber within which is contained fissionable fuel pellet segments, wedge members interposed between the fuel segments, and a spring which, acting with wedge members, urges said fuel pellets radially into contact against the inner surface of the outer tube. The wedge members may be a fertile material convertible into fissionable fuel material by absorbing neutrons emitted from the fissionable fuel pellet segments. The costly grinding of cylindrical fuel pellets to close tolerances for snug engagement is reduced because the need to finish the exact size is eliminated. (AEC)

  9. Dynamic analysis of process reactors

    Energy Technology Data Exchange (ETDEWEB)

    Shadle, L.J.; Lawson, L.O.; Noel, S.D.


    The approach and methodology of conducting a dynamic analysis is presented in this poster session in order to describe how this type of analysis can be used to evaluate the operation and control of process reactors. Dynamic analysis of the PyGas{trademark} gasification process is used to illustrate the utility of this approach. PyGas{trademark} is the gasifier being developed for the Gasification Product Improvement Facility (GPIF) by Jacobs-Siffine Engineering and Riley Stoker. In the first step of the analysis, process models are used to calculate the steady-state conditions and associated sensitivities for the process. For the PyGas{trademark} gasifier, the process models are non-linear mechanistic models of the jetting fluidized-bed pyrolyzer and the fixed-bed gasifier. These process sensitivities are key input, in the form of gain parameters or transfer functions, to the dynamic engineering models.

  10. Photoneutron effects on pulse reactor kinetics for the Annular Core Research Reactor (ACRR).

    Energy Technology Data Exchange (ETDEWEB)

    Parma, Edward J., Jr.


    The Annular Core Research Reactor (ACRR) is a swimming-pool type pulsed reactor that maintains an epithermal neutron flux and a nine-inch diameter central dry cavity. One of its uses is neutron and gamma-ray irradiation damage studies on electronic components under transient reactor power conditions. In analyzing the experimental results, careful attention must be paid to the kinetics associated with the reactor to ensure that the transient behavior of the electronic device is understood. Since the ACRR fuel maintains a substantial amount of beryllium, copious quantities of photoneutrons are produced that can significantly alter the expected behavior of the reactor power, especially following a reactor pulse. In order to understand these photoneutron effects on the reactor kinetics, the KIFLE transient reactor-analysis code was modified to include the photoneutron groups associated with the beryllium. The time-dependent behavior of the reactor power was analyzed for small and large pulses, assuming several initial conditions including following several pulses during the day, and following a long steady-state power run. The results indicate that, for these types of initial conditions, the photoneutron contribution to the reactor pulse energy can have a few to tens of percent effect.

  11. Flexible Conversion Ratio Fast Reactor Systems Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Neil Todreas; Pavel Hejzlar


    Conceptual designs of lead-cooled and liquid salt-cooled fast flexible conversion ratio reactors were developed. Both concepts have cores reated at 2400 MWt placed in a large-pool-type vessel with dual-free level, which also contains four intermediate heat exchanges coupling a primary coolant to a compact and efficient supercritical CO2 Brayton cycle power conversion system. Decay heat is removed passively using an enhanced Reactor Vessel Auxiliary Cooling System and a Passive Secondary Auxiliary Cooling System. The most important findings were that (1) it is feasible to design the lead-cooled and salt-cooled reactor with the flexible conversion ratio (CR) in the range of CR=0 and CR=1 n a manner that achieves inherent reactor shutdown in unprotected accidents, (2) the salt-cooled reactor requires Lithium thermal Expansion Modules to overcme the inherent salt coolant's large positive coolant temperature reactivity coefficient, (3) the preferable salt for fast spectrum high power density cores is NaCl-Kcl-MgCl2 as opposed to fluoride salts due to its better themal-hydraulic and neutronic characteristics, and (4) both reactor, but attain power density 3 times smaller than that of the sodium-cooled reactor.

  12. Massive computation methodology for reactor operation (MACRO)

    Energy Technology Data Exchange (ETDEWEB)

    Gustavsson, Cecilia; Pomp, Stephan; Sjoestrand, Henrik; Wallin, Gustav; Oesterlund, Michael [Division of applied nuclear physics, Department of physics and astronomy, Uppsala University, Laegerhyddsvaegen 1, 751 20 Uppsala (Sweden); Koning, Arjan; Rochman, Dimitri [Nuclear Research and consultancy Group (NRG) Westerduinweg 3, Petten (Netherlands); Bejmer, Klaes-Hakan [Vattenfall Nuclear Fuel AB, Jaemtlandsgatan 99, Vaellingby (Sweden); Henriksson, Hans [Vattenfall Research and Development AB, Jaemtlandsgatan 99, Vaellingby (Sweden)


    Today, nuclear data libraries do not handle uncertainties from nuclear data in a consistent manner and the reactor codes do not request uncertainties in nuclear data input. Thus, the output from these codes have unknown uncertainties. The plan is to use a method proposed by Koning and Rochman to investigate the propagation of nuclear data uncertainties into reactor physics codes and macroscopic parameters. A project (acronym MACRO) has started at Uppsala University in collaboration with A. Koning and with financial support from Vattenfall AB and the Swedish Research Council within the GENIUS (Generation IV research in universities of Sweden) project. In the proposed method the uncertainties in nuclear model parameters will be derived from theoretical considerations and comparisons of nuclear model results with experimental cross-section data. Given the probability distribution in the model parameters a large set of random, complete ENDF-formatted nuclear data libraries will be created using the TALYS code. The generated nuclear data libraries will then be used in neutron transport codes to obtain macroscopic reactor parameters. For this, models of reactor systems with proper geometry and elements will be used. This will be done for all data libraries and the variation of the final results will be regarded as a systematic uncertainty in the investigated reactor parameter. The understanding of these systematic uncertainties is especially important for the design and intercomparison of new reactor concepts, i.e., Generation IV, and optimization applications for current generation reactors is envisaged. (authors)

  13. Prolongation of the BOR-60 reactor operation

    Directory of Open Access Journals (Sweden)

    Alexey l. Izhutov


    Full Text Available The fast neutron reactor BOR-60 is one of the key experimental facilities worldwide to perform large-scale tests of fuel, absorbing, and structural materials for advanced reactors. The BOR-60 reactor was put into operation in December 1969, and by the end of 2014 it had been operating on power for ∼265,000 hours. BOR-60 still demonstrates potential capabilities to extend the lifetime of sodium-cooled fast reactors. The BOR-60 lifetime should have expired at the end of 2014. Over the past few years, a great scope of work has been performed to justify the possibility of extending its lifetime. The work included inspection of the equipment conditions, calculations and experimental research on operating parameters and the conditions of nonremovable components, investigation of the structural material samples after their long-term operation under irradiation, etc. Based on the results of the work performed, the residual lifetime was evaluated and the reactor operator made a decision to extend the lifetime period of the BOR-60 reactor. After considering both a set of documents about the reactor conditions and the positive decision of independent experts, the Regulatory Authority of the Russian Federation extended the BOR-60 operating license up to 2020.

  14. Reactor Monitoring with Antineutrinos - A Progress Report (United States)

    Bernstein, Adam


    The Reactor Safeguards regime is the name given to a set of protocols and technologies used to monitor the consumption and production of fissile materials in nuclear reactors. The Safeguards regime is administered by the International Atomic Energy Agency (IAEA), and is an essential component of the global Treaty on Nuclear Nonproliferation, recently renewed by its 189 remaining signators. (The 190th, North Korea, withdrew from the Treaty in 2003). Beginning in Russia in the 1980s, a number of researchers worldwide have experimentally demonstrated the potential of cubic meter scale antineutrino detectors for non-intrusive real-time monitoring of fissile inventories and power output of reactors. The detectors built so far have operated tens of meters from a reactor core, outside of the containment dome, largely unattended and with remote data acquisition for an entire 1.5 year reactor cycle, and have achieved levels of sensitivity to fissile content of potential interest for the IAEA safeguards regime. In this article, I will describe the unique advantages of antineutrino detectors for cooperative monitoring, consider the prospects and benefits of increasing the range of detectability for small reactors, and provide a partial survey of ongoing global research aimed at improving near-field and far field monitoring and discovery of nuclear reactors.

  15. Advanced Demonstration and Test Reactor Options Study

    Energy Technology Data Exchange (ETDEWEB)

    Petti, David Andrew [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hill, R. [Argonne National Lab. (ANL), Argonne, IL (United States); Gehin, J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gougar, Hans David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Strydom, Gerhard [Idaho National Lab. (INL), Idaho Falls, ID (United States); Heidet, F. [Argonne National Lab. (ANL), Argonne, IL (United States); Kinsey, J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Grandy, Christopher [Argonne National Lab. (ANL), Argonne, IL (United States); Qualls, A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Brown, Nicholas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Powers, J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hoffman, E. [Argonne National Lab. (ANL), Argonne, IL (United States); Croson, D. [Idaho National Lab. (INL), Idaho Falls, ID (United States)


    Global efforts to address climate change will require large-scale decarbonization of energy production in the United States and elsewhere. Nuclear power already provides 20% of electricity production in the United States (U.S.) and is increasing in countries undergoing rapid growth around the world. Because reliable, grid-stabilizing, low emission electricity generation, energy security, and energy resource diversity will be increasingly valued, nuclear power’s share of electricity production has a potential to grow. In addition, there are non electricity applications (e.g., process heat, desalination, hydrogen production) that could be better served by advanced nuclear systems. Thus, the timely development, demonstration, and commercialization of advanced nuclear reactors could diversify the nuclear technologies available and offer attractive technology options to expand the impact of nuclear energy for electricity generation and non-electricity missions. The purpose of this planning study is to provide transparent and defensible technology options for a test and/or demonstration reactor(s) to be built to support public policy, innovation and long term commercialization within the context of the Department of Energy’s (DOE’s) broader commitment to pursuing an “all of the above” clean energy strategy and associated time lines. This planning study includes identification of the key features and timing needed for advanced test or demonstration reactors to support research, development, and technology demonstration leading to the commercialization of power plants built upon these advanced reactor platforms. This planning study is consistent with the Congressional language contained within the fiscal year 2015 appropriation that directed the DOE to conduct a planning study to evaluate “advanced reactor technology options, capabilities, and requirements within the context of national needs and public policy to support innovation in nuclear energy

  16. Maratona Atenas 2004: a (recategorização em textos jornalísticos The 2004 Athens marathon: the (recategorization in media texts

    Directory of Open Access Journals (Sweden)

    Milton Francisco


    Full Text Available O processo de referenciação implica (recategorizar os objetos discursivamente (cf. Mondada 1997; Mondada e Dubois 2003. Este artigo consiste em uma reflexão epistemológica sobre processo de (recategorização, voltando-se para o procedimento do enunciador ao referir e (recategorizar os objetos. Focaliza-se a (reavaliação que os objetos podem ter a cada designação. Esse processo é analisado em textos jornalísticos escritos de caráter informativo e opinativo, os quais têm como tema o episódio atípico ocorrido com o atleta brasileiro Vanderlei Cordeiro de Lima na prova de Maratona dos Jogos Olímpicos de Atenas, em 2004. Os resultados apontam que, no texto informativo, em geral o ponto de vista e valores atribuídos, por exemplo, ao episódio e a Vanderlei, originam-se de discurso alheio, enquanto que, no texto opinativo, o autor geralmente mescla seu ponto de vista e valores com os do discurso alheio. Em ambos os tipos de texto, prevalece grande diversidade de categorias, a qual corresponde à heterogeneidade semântico-referencial dos textos.The process of referentiation implies (recategorizing the objects discursively (Mondada 1997; Mondada and Dubois 2003. This article is an epistemo logical reflection about the process of (recategorization, focusing at the enunciator's procedure when referring and (recategorizing objects. It's focused the (reevaluation that the objects can have in each designation. This process is analyzed in written media informative and opinion texts whose topic is the odd episode that happened to the Brazilian athlete Vanderlei Cordeiro de Lima during the marathon competition at the Olympic Games in Athens, in 2004. The results show that in informative texts, in general, point of view and attributed values, for example, to the episode and to Vanderlei, originated from a third person; whereas in opinion texts, the author usually mixes his/her point of view and values with the ones of a third person's. In both

  17. Transients in reactors for power systems compensation (United States)

    Abdul Hamid, Haziah

    This thesis describes new models and investigations into switching transient phenomena related to the shunt reactors and the Mechanically Switched Capacitor with Damping Network (MSCDN) operations used for reactive power control in the transmission system. Shunt reactors and MSCDN are similar in that they have reactors. A shunt reactor is connected parallel to the compensated lines to absorb the leading current, whereas the MSCDN is a version of a capacitor bank designed as a C-type filter for use in the harmonic-rich environment. In this work, models have been developed and transient overvoltages due to shunt reactor deenergisation were estimated analytically using MathCad, a mathematical program. Computer simulations used the ATP/EMTP program to reproduce both single-phase and three-phase shunt reactor switching at 275 kV operational substations. The effect of the reactor switching on the circuit breaker grading capacitor was also examined by considering various switching conditions.. The main original achievement of this thesis is the clarification of failure mechanisms occurring in the air-core filter reactor due to MSCDN switching operations. The simulation of the MSCDN energisation was conducted using the ATP/EMTP program in the presence of surge arresters. The outcome of this simulation shows that extremely fast transients were established across the air-core filter reactor. This identified transient event has led to the development of a detailed air-core reactor model, which accounts for the inter-turn RLC parameters as well as the stray capacitances-to-ground. These parameters are incorporated into the transient simulation circuit, from which the current and voltage distribution across the winding were derived using electric field and equivalent circuit modelling. Analysis of the results has revealed that there are substantial dielectric stresses imposed on the winding insulation that can be attributed to a combination of three factors. (i) First, the

  18. Reactor and method for production of nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Sunkara, Mahendra Kumar; Kim, Jeong H.; Kumar, Vivekanand


    A reactor and method for production of nanostructures, including metal oxide nanowires or nanoparticles, are provided. The reactor includes a regulated metal powder delivery system in communication with a dielectric tube; a plasma-forming gas inlet, whereby a plasma-forming gas is delivered substantially longitudinally into the dielectric tube; a sheath gas inlet, whereby a sheath gas is delivered into the dielectric tube; and a microwave energy generator coupled to the dielectric tube, whereby microwave energy is delivered into a plasma-forming gas. The method for producing nanostructures includes providing a reactor to form nanostructures and collecting the formed nanostructures, optionally from a filter located downstream of the dielectric tube.

  19. Facility for a Low Power Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Chalker, R. G.


    Preliminary investigation indicates that a reactor facility with ample research provisions for use by University or other interested groups, featuring safety in design, can be economically constructed in the Los Angeles area. The complete installation, including an underground gas-tight reactor building, with associated storage and experiment assembly building, administration offices, two general laboratory buildings, hot latoratory and lodge, can be constructed for approxinately $1,500,000. This does not include the cost of the reactor itself or of its auxiliary equipment,


    Directory of Open Access Journals (Sweden)

    Dumitru POPESCU


    Full Text Available The main objective of this work is the design and implementation of control solutions for petrochemical processes, namely the control and optimization of a pyrolysis reactor, the key-installation in the petrochemical industry. We present the technological characteristics of this petrochemical process and some aspects about the proposed control system solution for the ethylene plant. Finally, an optimal operating point for the reactor is found, considering that the process has a nonlinear multi-variable structure. The results have been implemented on an assembly of pyrolysis reactors on a petrochemical platform from Romania.

  1. A study of reactor vessel integrity assessment

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Hoon [Korea Institute of Nuclear Safety, Taejon (Korea, Republic of); Kim, Jong Kyung; Shin, Chang Ho; Seo, Bo Kyun [Hanyang Univ., Seoul (Korea, Republic of)


    The fast neutron fluence at the Reactor Pressure Vessel(RPV) of KNGR designed for 60 years lifetime was calculated by full-scope Monte Carlo simulation for reactor vessel integrity assessment. KNGR core geometry was modeled on a three-dimensional representation of the one-sixteenth of the reactor in-vessel component. Each fuel assemblies were modeled explicitly, and each fuel pins were axially divided into 5 segments. The maximum flux of 4.3 x 10{sup 10} neutrons/cm{sup 2}. sec at the RPV was obtained by tallying neutrons crossing the beltline of inner surface of the RPV.

  2. Uranium mill monitoring for natural fission reactors

    Energy Technology Data Exchange (ETDEWEB)

    Apt, K.E.


    Isotopic monitoring of the product stream from operating uranium mills is proposed for discovering other possible natural fission reactors; aspects of their occurrence and discovery are considered. Uranium mill operating characteristics are formulated in terms of the total uranium capacity, the uranium throughput, and the dilution half-time of the mill. The requirements for detection of milled reactor-zone uranium are expressed in terms of the dilution half-time and the sampling frequency. Detection of different amounts of reactor ore with varying degrees of /sup 235/U depletion is considered.

  3. Pyrometric fuel particle measurements in pressurised reactors

    Energy Technology Data Exchange (ETDEWEB)

    Hernberg, R.; Joutsenoja, T. [Tampere Univ. of Technology (Finland)


    A fiberoptic two-colour pyrometric technique for fuel particle temperature and size measurement is modified and applied to three pressurized reactors of different type in Finland, Germany and France. A modification of the pyrometric method for simultaneous in situ measurement of the temperature and size of individual pulverized coal particles at the pressurized entrained flow reactor in Jyvaeskylae was developed and several series of measurements were made. In Orleans a fiberoptic pyrometric device was installed to a pressurised thermogravimetric reactor and the two-colour temperatures of fuel samples were measured. Some results of these measurements are presented. The project belongs to EU`s Joule 2 extension research programme. (author)

  4. Neutronic Reactor Design to Reduce Neutron Loss (United States)

    Miles, F. T.


    A nuclear reactor construction is described in which an unmoderated layer of the fissionable material is inserted between the moderated portion of the reactor core and the core container steel wall. The wall is surrounded by successive layers of pure fertile material and moderator containing fertile material. The unmoderated layer of the fissionable material will insure that a greater portion of fast neutrons will pass through the steel wall than would thermal neutrons. Since the steel has a smaller capture cross section for the fast neutrons, greater nunnbers of neutrons will pass into the blanket, thereby increasing the over-all efficiency of the reactor. (AEC)

  5. Advances in ICF power reactor design (United States)

    Hogan, W. J.; Kulcinski, G. L.


    Fifteen ICF power reactor design studies published since 1980 are reviewed to illuminate the design trends they represent. There is a clear, continuing trend toward making ICF reactors inherently safer and environmentally benign. Since this trend accentuates inherent advantages of ICF reactors, it is expected to be further emphasized in the future. An emphasis on economic competitiveness appears to be a somewhat newer trend. Lower cost of electricity, smaller initial size (and capital cost), and more affordable development paths are three of the issues being addressed with new studies.

  6. Passive compact molten salt reactor (PCMSR), modular thermal breeder reactor with totally passive safety system (United States)

    Harto, Andang Widi


    Design Study Passive Compact Molten Salt Reactor (PCMSR) with totally passive safety system has been performed. The term of Compact in the PCMSR name means that the reactor system is designed to have relatively small volume per unit power output by using modular and integral concept. In term of modular, the reactor system consists of three modules, i.e. reactor module, turbine module and fuel management module. The reactor module is an integral design that consists of reactor, primary and intermediate heat exchangers and passive post shutdown cooling system. The turbine module is an integral design of a multi heating, multi cooling, regenerative gas turbine. The fuel management module consists of all equipments related to fuel preparation, fuel reprocessing and radioactive handling. The preliminary calculations show that the PCMSR has negative temperature and void reactivity coefficient, passive shutdown characteristic related to fuel pump failure and possibility of using natural circulation for post shutdown cooling system.

  7. Hydrodynamics of multi-phase packed bed micro-reactors

    NARCIS (Netherlands)

    Márquez Luzardo, N.M.


    Why to use packed bed micro-reactors for catalyst testing? Miniaturized packed bed reactors have a large surface-to-volume ratio at the reactor and particle level that favors the heat- and mass-transfer processes at all scales (intra-particle, inter-phase and inter-particle or reactor level). If the

  8. 10 CFR 1.43 - Office of Nuclear Reactor Regulation. (United States)


    ... 10 Energy 1 2010-01-01 2010-01-01 false Office of Nuclear Reactor Regulation. 1.43 Section 1.43... Program Offices § 1.43 Office of Nuclear Reactor Regulation. The Office of Nuclear Reactor Regulation— (a... health and safety, the environment, or the safeguarding of nuclear reactor facilities; (c) Assesses and...

  9. 78 FR 73898 - Operator Licensing Examination Standards for Power Reactors (United States)


    ... COMMISSION Operator Licensing Examination Standards for Power Reactors AGENCY: Nuclear Regulatory Commission... Standards for Power Reactors.'' DATES: Submit comments by February 7, 2014. Comments received after this... of New Reactors; or Timothy Kolb, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory...

  10. 40 CFR 63.1406 - Reactor batch process vent provisions. (United States)


    ... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Reactor batch process vent provisions... § 63.1406 Reactor batch process vent provisions. (a) Emission standards. Owners or operators of reactor... reactor batch process vent located at a new affected source shall control organic HAP emissions by...

  11. Advanced research reactor fuel development

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chang Kyu; Pak, H. D.; Kim, K. H. [and others


    The fabrication technology of the U{sub 3}Si fuel dispersed in aluminum for the localization of HANARO driver fuel has been launches. The increase of production yield of LEU metal, the establishment of measurement method of homogeneity, and electron beam welding process were performed. Irradiation test under normal operation condition, had been carried out and any clues of the fuel assembly breakdown was not detected. The 2nd test fuel assembly has been irradiated at HANARO reactor since 17th June 1999. The quality assurance system has been re-established and the eddy current test technique has been developed. The irradiation test for U{sub 3}Si{sub 2} dispersed fuels at HANARO reactor has been carried out in order to compare the in-pile performance of between the two types of U{sub 3}Si{sub 2} fuels, prepared by both the atomization and comminution processes. KAERI has also conducted all safety-related works such as the design and the fabrication of irradiation rig, the analysis of irradiation behavior, thermal hydraulic characteristics, stress analysis for irradiation rig, and thermal analysis fuel plate, for the mini-plate prepared by international research cooperation being irradiated safely at HANARO. Pressure drop test, vibration test and endurance test were performed. The characterization on powders of U-(5.4 {approx} 10 wt%) Mo alloy depending on Mo content prepared by rotating disk centrifugal atomization process was carried out in order to investigate the phase stability of the atomized U-Mo alloy system. The {gamma}-U phase stability and the thermal compatibility of atomized U-16at.%Mo and U-14at.%Mo-2at.%X(: Ru, Os) dispersion fuel meats at an elevated temperature have been investigated. The volume increases of U-Mo compatibility specimens were almost the same as or smaller than those of U{sub 3}Si{sub 2}. However the atomized alloy fuel exhibited a better irradiation performance than the comminuted alloy. The RERTR-3 irradiation test of nano

  12. Reactor modeling and physicochemical properties characterization for a polyethylene fluidized bed reactor


    Fernandes, F.A.N.; LONA BATISTA,L. M. F.


    A new steady state model for the fluidized bed reactor and a physicochemical characterization model were developed for the simulation of polyethylene production using gas-phase technology. The association of these models was done in order to predict the characteristics of the polymer produced in the fluidized bed reactor (molecular weight, polydispersity, melt index, and other characteristics) throughout the reactor and also to predict the growth of the polymer particle.

  13. A fast and flexible reactor physics model for simulating neutron spectra and depletion in fast reactors (United States)

    Recktenwald, Geoff; Deinert, Mark


    Determining the time dependent concentration of isotopes within a nuclear reactor core is central to the analysis of nuclear fuel cycles. We present a fast, flexible tool for determining the time dependent neutron spectrum within fast reactors. The code (VBUDS: visualization, burnup, depletion and spectra) uses a two region, multigroup collision probability model to simulate the energy dependent neutron flux and tracks the buildup and burnout of 24 actinides, as well as fission products. While originally developed for LWR simulations, the model is shown to produce fast reactor spectra that show high degree of fidelity to available fast reactor benchmarks.

  14. Development of technology for next generation reactor - Development of next generation reactor in Korea -

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Kyun; Chang, Moon Heuy; Hwang, Yung Dong [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)] [and others


    The project, development of next generation reactor, aims overall related technology development and obtainment of related license in 2001. The development direction is to determine the reactor type and to build up the design concept in 1994. For development trend analysis of foreign next generation reactor, level-1 PSA, fuel cycle analysis and computer code development are performed on System 80+ and AP 600. Especially for design characteristics analysis and volume upgrade of AP 600, nuclear fuel and reactor core design analysis, coolant circuit design analysis, mechanical structure design analysis and safety analysis etc. are performed. (Author).

  15. Chemical reactor modeling multiphase reactive flows

    CERN Document Server

    Jakobsen, Hugo A


    Chemical Reactor Modeling closes the gap between Chemical Reaction Engineering and Fluid Mechanics.  The second edition consists of two volumes: Volume 1: Fundamentals. Volume 2: Chemical Engineering Applications In volume 1 most of the fundamental theory is presented. A few numerical model simulation application examples are given to elucidate the link between theory and applications. In volume 2 the chemical reactor equipment to be modeled are described. Several engineering models are introduced and discussed. A survey of the frequently used numerical methods, algorithms and schemes is provided. A few practical engineering applications of the modeling tools are presented and discussed. The working principles of several experimental techniques employed in order to get data for model validation are outlined. The monograph is based on lectures regularly taught in the fourth and fifth years graduate courses in transport phenomena and chemical reactor modeling, and in a post graduate course in modern reactor m...

  16. Microbial degradation of MTBE in reactors

    DEFF Research Database (Denmark)

    Waul, Christopher Kevin; Arvin, Erik; Schmidt, Jens Ejbye


    , toluene, ethylbenzene and xylenes, may reduce the removal rates of MTBE, or prevent its removal in reactors. With mathematical modelling, the long startup time required for some MTBE degrading reactors could be predicted. Long startup times of up to 200 days were due to the low maximum growth rate...... findings were: membrane bioreactors and fluidized bed reactors had the highest volumetric removal rates of all reactors studied, in the order of 1 000 mg/(l d); competition for oxygen, nutrients and occupancy between MTBE degraders and oxidisers of co-contaminants such as, ammonium and the group of benzene...... of the MTBE degraders, in the order of 0.1 d−1 or less, at 25 °C. However, despite this, high volumetric MTBE removal rates were found to be possible after the startup period when the biomass concentration reached a steady state....

  17. Heat pipe nuclear reactor for space power (United States)

    Koening, D. R.


    A heat-pipe-cooled nuclear reactor has been designed to provide 3.2 MWth to an out-of-core thermionic conversion system. The reactor is a fast reactor designed to operate at a nominal heat-pipe temperature of 1675 K. Each reactor fuel element consists of a hexagonal molybdenum block which is bonded along its axis to one end of a molybdenum/lithium-vapor heat pipe. The block is perforated with an array of longitudinal holes which are loaded with UO2 pellets. The heat pipe transfers heat directly to a string of six thermionic converters which are bonded along the other end of the heat pipe. An assembly of 90 such fuel elements forms a hexagonal core. The core is surrounded by a thermal radiation shield, a thin thermal neutron absorber, and a BeO reflector containing boron-loaded control drums.

  18. Thermal Shield and Reactor Structure Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Collier, A.R.


    The purpose of this report is to present reactor structure and thermal shield temperature data taken during P-3 and P-5 cycles and compare them with design calculations in order to predict temperatures at higher power levels.

  19. N Reactor Deactivation Program Plan. Revision 4

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, J.L.


    This N Reactor Deactivation Program Plan is structured to provide the basic methodology required to place N Reactor and supporting facilities {center_dot} in a radiologically and environmentally safe condition such that they can be decommissioned at a later date. Deactivation will be in accordance with facility transfer criteria specified in Department of Energy (DOE) and Westinghouse Hanford Company (WHC) guidance. Transition activities primarily involve shutdown and isolation of operational systems and buildings, radiological/hazardous waste cleanup, N Fuel Basin stabilization and environmental stabilization of the facilities. The N Reactor Deactivation Program covers the period FY 1992 through FY 1997. The directive to cease N Reactor preservation and prepare for decommissioning was issued by DOE to WHC on September 20, 1991. The work year and budget data supporting the Work Breakdown Structure in this document are found in the Activity Data Sheets (ADS) and the Environmental Restoration Program Baseline, that are prepared annually.

  20. Hysteresis phenomenon in nuclear reactor dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Pirayesh, Behnam; Pazirandeh, Ali [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Dept. of Nuclear Engineering, Science and Research Branch; Akbari, Monireh [Shahid Rajaee Teacher Training Univ., Tehran (Iran, Islamic Republic of). Dept. of Mathematics


    This paper applies a nonlinear analysis method to show that hysteresis phenomenon, due to the Saddle-node bifurcation, may occur in the nuclear reactor. This phenomenon may have significant effects on nuclear reactor dynamics and can even be the beginning of a nuclear reactor accident. A system of four dimensional nonlinear ordinary differential equations was considered to study the hysteresis phenomenon in a typical nuclear reactor. It should be noted that the reactivity was considered as a nonlinear function of state variables. The condition for emerging hysteresis was investigated using Routh-Hurwitz criterion and Sotomayor's theorem for saddle node bifurcation. A numerical analysis is also provided to illustrate the analytical results.