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Sample records for athene reactor

  1. Miracles at Athens Games

    Institute of Scientific and Technical Information of China (English)

    贝贝

    2004-01-01

    Just before the Athens Olympic Games drew to its close on August 29, 2004, a victory in taekwondoI marked China's 32nd gold medal and highlighted the Chinese storm that swept over Athens. The last two weeks saw marked improvement in the overall level of China's athletes.

  2. Alkmaioniderne - politik og sport i antikkens Athen

    DEFF Research Database (Denmark)

    Nielsen, Thomas Heine

    2013-01-01

    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. Reactors

    CERN Document Server

    International Electrotechnical Commission. Geneva

    1988-01-01

    This standard applies to the following types of reactors: shunt reactors, current-limiting reactors including neutral-earthing reactors, damping reactors, tuning (filter) reactors, earthing transformers (neutral couplers), arc-suppression reactors, smoothing reactors, with the exception of the following reactors: small reactors with a rating generally less than 2 kvar single-phase and 10 kvar three-phase, reactors for special purposes such as high-frequency line traps or reactors mounted on rolling stock.

  4. The Ancient City—Athens

    Institute of Scientific and Technical Information of China (English)

    黄刚

    2004-01-01

    With thousands of years of history and mythology under its belt, Athens---yarned for the olivetree---loving Athena is more than a concrete jungle. It's an city enlivened with plenty of outdoor cafes, pedestrian streets, parks, gardens and characters. If you get into the spirit of things, you might not even notice the layer of smog hanging overhead.

  5. Olympic Flame Burning In Athens

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    <正>At 6:00pm March 25 (Beijing time), 2004 Athens Olympic flame was lit in Greece’s ancient sanctuary, indicating that the torch relay started.The torch relay, established at the Berlin Games in 1936, will for the first time visit all five continents

  6. Athens

    Institute of Scientific and Technical Information of China (English)

    高登

    2005-01-01

    Athensis located in the Attica basin, in the center of the Greekterritory.It’s a seasid ecitysurroundedbymanyhillsandmountains.ThehighestmountainoftheareaisMountParnassus.ThecityofAthenscoversanareaof29squareskm.

  7. 2013 Athens-Clarke County, Georgia Imagery

    Data.gov (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...

  8. Water in Athens Then and Now

    Science.gov (United States)

    Christaki, Maria

    2015-04-01

    The presentation examines the water sources and the water supply projects in Athens in relation to the historical, urban and demographic development since 3500 BC. Athens and the Athens basin were inhabited from the Late Neolithic period (about 5300-4500 BC.). In recent years, after thorough investigations and excavations in the north and south side of the Acropolis, the Agora and the Dipylon, conclusions were drawn regarding the historical construction and residential development of Athens. The findings show that the Athenians had settled permanently on the sides of the Acropolis from Hysteroneolithic or Final Neolithic period (3500-3000 BC.). The water provision was primarily secured by using wells and natural springs, such as the Neolithic wells near the Klepsydra spring. The climate in Attica is dry Mediterranean with sunny and dry summers and wet and mild winters. The annual precipitation in the city of Athens is about 400 mm and long dry periods are been detected in historical times all the way to today. Since prehistoric times, the city of Athens and the wider region of Attica did not contain many natural water sources so aquatic reserves were never adequate to meet the needs of residents, as these changed over time The lack of water in Attica drove its inhabitants to study the flow of rivers and penetration of rain into the earth to discover and extract hidden waters. This enabled Athenians to acquire technical expertise and develop a significant hydrotechnologic culture, as evidenced by their works. As the population of Athens and the need for water increased residents - among others - turned to obtaining water from distant sources and construct aqueducts that brought water into the city using gravity. In the mid of 6th century BC (tyranny of Peisistrateidon) and while the population was 300,000 the Peisistrateio aqueduct built. After the 6th. century BC there were, fountains, cisterns, reservoirs and aqueducts throughout the city. In Roman Athens, the

  9. Aerosol Index Dynamics over Athens and Beijing

    Science.gov (United States)

    Christodoulakis, J.; Varotsos, C.; Tzanis, C.; Xue, Y.

    2014-11-01

    We present the analysis of monthly mean Aerosol Index (AI) values, over Athens, Greece, and Beijing, China, for the period 1979- 2012. The aim of the analysis is the identification of time scaling in the AI time series, by using a data analysis technique that would not be affected by the non-stationarity of the data. The appropriate technique satisfying this criterion is the Detrended Fluctuation Analysis (DFA). For the deseasonalization of time series classic Wiener method was applied filtering out the seasonal - 3 months, semiannual - 6 months and annual - 12 months periods. The data analysis for both Athens and Beijing revealed that the exponents α for both time periods are greater than 0.5 indicating that persistence of the correlations in the fluctuations of the deseasonalized AI values exists for time scales between about 4 months and 3.5 years (for the period 1979-1993) or 4 years (for the period 1996-2012).

  10. Athens sølvminer i Laurion

    DEFF Research Database (Denmark)

    Isager, Signe

    2016-01-01

    Antikkens minedrift belyses bedst med udgangspunkt i de såkaldte sølvminer i det sydlige Attika. Fysiske levn af de installationer, som hørte malmudvindingen til kan stadig ses i terrænet, og Athens historie i øvrigt er så veldokumenteret også skriftligt, at det lader sig gøre at sætte levnene in...

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

    CERN Multimedia

    ATLAS Experiment

    2012-01-01

    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. http://atlas-live-virtual-visit.web.cern.ch/atlas-live-virtual-visit/2012/Athens-2012.html

  12. Reactor

    Science.gov (United States)

    Evans, Robert M.

    1976-10-05

    1. A neutronic reactor having a moderator, coolant tubes traversing the moderator from an inlet end to an outlet end, bodies of material fissionable by neutrons of thermal energy disposed within the coolant tubes, and means for circulating water through said coolant tubes characterized by the improved construction wherein the coolant tubes are constructed of aluminum having an outer diameter of 1.729 inches and a wall thickness of 0.059 inch, and the means for circulating a liquid coolant through the tubes includes a source of water at a pressure of approximately 350 pounds per square inch connected to the inlet end of the tubes, and said construction including a pressure reducing orifice disposed at the inlet ends of the tubes reducing the pressure of the water by approximately 150 pounds per square inch.

  13. Simulation of the convective mixed layer in Athens

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-10-01

    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)

  14. 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...

  15. art@CMS at 2016 Athens Science Festival

    CERN Multimedia

    Athens, Greece

    2016-01-01

    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.

  16. Spotlight on Athens%雅典风情

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Athens-the name bnngs to mind buildings with tall,white columns and statues of Greek gods and goddesses.Museums take visitors back to the time of ancient Greece.When visiting the city,visitors feel like they're in the middle of a history lesson.

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

    Directory of Open Access Journals (Sweden)

    Mirones Steven

    2009-04-01

    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.

  18. The plague of Athens: an ancient act of bioterrorism?

    Science.gov (United States)

    Papagrigorakis, Manolis J; Synodinos, Philippos N; Stathi, Angeliki; Skevaki, Chrysanthi L; Zachariadou, Levantia

    2013-09-01

    Recent data implicate Salmonella enterica serovar Typhi as a causative pathogen of the Plague of Athens during the Peloponnesian War (430-426 bc). According to Thucydides, the sudden outbreak of the disease may link to poisoning of the water reservoirs by the Spartans. The siege of a city was aimed at exhausting the supplies of a population, which often led to the outbreak and spread of epidemics. Poisoning of the water reservoirs of a besieged city as an act of bioterrorism would probably shorten the necessary time for such conditions to appear.

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

    Directory of Open Access Journals (Sweden)

    Vassiliki Lalioti

    2013-11-01

    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.

  20. The Different Education View Between Athens and Sparta

    Institute of Scientific and Technical Information of China (English)

    Zhang Lijuan

    2016-01-01

    People have been concerned about education since ancient time. The right education view not only contributes to making the country move forward, but also helps human's individual growth. The education of ancient Greece is the home to western education, which has an important effect on the development of contemporary education. Sparta and Athens are the typical representative country-states. The thesis compares the two kinds of education from five aspects which are education feature, education purpose, and education content. And it summarizes reasons why they are different, which deepens people's understanding of education view in ancient Greece.

  1. Mercury in the Urban Topsoil of Athens, Greece

    Directory of Open Access Journals (Sweden)

    Efstratios Kelepertzis

    2015-04-01

    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.

  2. 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...

  3. Nuclear Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Hogerton, John

    1964-01-01

    This pamphlet describes how reactors work; discusses reactor design; describes research, teaching, and materials testing reactors; production reactors; reactors for electric power generation; reactors for supply heat; reactors for propulsion; reactors for space; reactor safety; and reactors of tomorrow. The appendix discusses characteristics of U.S. civilian power reactor concepts and lists some of the U.S. reactor power projects, with location, type, capacity, owner, and startup date.

  4. ATHENS SEASONAL VARIATION OF GROUND RESISTANCE PREDICTION USING NEURAL NETWORKS

    Directory of Open Access Journals (Sweden)

    S. Anbazhagan

    2015-10-01

    Full Text Available The objective in ground resistance is to attain the most minimal ground safety esteem conceivable that bodes well monetarily and physically. An application of artificial neural networks (ANN to presage and relegation has been growing rapidly due to sundry unique characteristics of ANN models. A decent forecast is able to capture the dubiousness associated with those ground resistance. A portion of the key instabilities are soil composition, moisture content, temperature, ground electrodes and spacing of the electrodes. Propelled by this need, this paper endeavors to develop a generalized regression neural network (GRNN to predict the ground resistance. The GRNN has a single design parameter and expeditious learning and efficacious modeling for nonlinear time series. The precision of the forecast is applied to the Athens seasonal variation of ground resistance that shows the efficacy of the proposed approach.

  5. [Attempted suicide during the financial crisis in Athens].

    Science.gov (United States)

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

    2014-01-01

    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. Observing variable stars at the University of Athens Observatory

    Science.gov (United States)

    Gazeas, K.; Manimanis, V. N.; Niarchos, P. G.

    In 1999 the University of Athens installed a 0.4-m Cassegrain telescope (CCT-16, by DFM Engineering) on the roof of the Department of Astrophysics, Astronomy and Mechanics, equipped with a ST-8 CCD camera and Bessel UBVRI filters. Although the telescope was built for educational purposes, we found it can be a perfect research instrument, as we can obtain fine quality light curves of bright variable stars, even from a place close to the city center. Light curves of the δ Scuti star V1162 Ori and of the sdB star PG 1336-018 are presented, showing the ability of a 40-cm telescope to detect negligible luminosity fluctuations of relatively bright variable stars. To date, we succeed in making photometry of stars down to 15th magnitude with satisfactory results. We expect to achieve even better results in the future, as our methods still improve, and as the large number of relatively bright stars gives us the chance to study various fields of CCD photometry of variables.

  7. Seismic Hazard Assessment in the Aspospirgos Area, Athens - Greece

    Science.gov (United States)

    Voulgaris, N.; Drakatos, G.; Lekkas, E.; Karastathis, V.; Valadaki, A.; Plessas, S.

    2005-12-01

    The extensive damages and human life loss related to the September 7, 1999 earthquake in the Athens area (Greece) initiated an effort to re-evaluate seismic hazard in various regions around the capital. One of the target areas selected within the framework of the specially designed research project ESTIA was the industrial area of Aspropirgos, where the epicenter of the main shock was located. The multidisciplinary approach towards seismic hazard assessment included a microseismicity survey and detailed geological and tectonic studies in the area in order to delineate and define the recently activated seismic sources in the area. Initially a portable network, consisting of seventeen (17) digital seismographs was installed and operated for 2 months during the autumn of 2004. A total of five hundred forty five (545) earthquakes (Mengineer is able to calculate specific design spectra for every site while combination with available vulnerability estimates could lead to more realistic seismic risk calculations. Acknowledgments We would like to thank the General Secretariat for Research and Technology of Greece for the partial support of this research, in the framework of ESTIA project.

  8. 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...

  9. Brominated flame retardants in Belgian little owl (Athene noctua) eggs

    Energy Technology Data Exchange (ETDEWEB)

    Jaspers, V.; Covaci, A.; Maervoet, J.; Dauwe, T.; Schepens, P.; Eens, M. [Antwerp Univ. (Belgium)

    2004-09-15

    Since the 1960s, polybrominated diphenylethers (PBDEs), a class of brominated flame retardants (BFRs), are widely used in textiles, plastics, electronic equipment and other materials. Their massive use has led to the ubiquitous presence of PBDEs in the environment and in biota in which the PBDE levels seem to increase rapidly. High concentrations of some congeners may cause adverse effects in both wildlife and in human populations1 and this has led to the growing concern of scientists over the last decade and to the need for more data on environmental levels of PBDEs. The little owl (Athene noctua) is a small sedentary predator, which makes it a very suitable biomonitoring species. This owl species feeds on a variety of preys, including small mammals and birds, reptiles, amphibians, earthworms and beetles, depending on the season and the local circumstances. Because very limited information is available about contamination levels in the little owl, a study was conducted to determine the concentrations of PBDEs, polybrominated biphenyls (PBBs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in deserted or addled eggs of little owls in Belgium. Eggs have been used successfully as a monitoring tool for persistent organic pollutants (POPs) in several studies. Although the analysis of POPs in deserted or addled eggs has clear limitations, these can be partially avoided by analysing only highly persistent components, for which the original composition will not change due to 'posthatching' microbiological degradation.

  10. Compliance in hypertensive patients attending an Athens hospital

    Directory of Open Access Journals (Sweden)

    Mastrogiannis D.

    2011-01-01

    Full Text Available Hypertension remains a silent disease. Symptoms occur several years since onset. Control remains poor in diagnosed patients. Only 20-22% of the patients control their condition.Aim: To investigate patients’ compliance with their drug treatment and any relationship of other factor with blood pressure values.Material and method: An exploratory study of 109 patients at a hospital in Athens was undertaken. Data collection was performed with a structured questionnaire. Answers were recorded by the researchers. Factors such as the duration of the drug treatment, BP values, salt consumption, exercise frequency, smoking as well as demographic data were recorded. SPSS v.15 was implemented to process data and a regression analysis was performed. Findings were considered as statistically significant at p value <0,05.Results: None of the patients was found to have an optimal or normal BP value. A great proportion of our sample were smokers (45%, 82,6% were not exercising at all and another 10,2% admitted they consumed too much salt on daily basis. Most of the participants (77,1% reported they received their medication according to their physician’s directions. Statistically significant correlations were found between the mean systolic blood pressure values and exercise (rpb=-0,162, p=0,042, compliance with drug treatment (rpb=-0,331, p<0,01, salt consumption (rpb=0,217, p=0,023 and age of participants (rs=0,263, p=0,08.Conclusions: Hypertensive patients in this sample don’t exercise, are overweight and despite receiving hypertensive treatment, there weren’t any normal BP values found.

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

    CERN Multimedia

    2013-01-01

    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.

  12. Heliophysics Research at the National Observatory of Athens: Communicating Science

    Science.gov (United States)

    Malandraki, Olga; Papaioannou, Athanasios; Patsou, Ioanna; Tziotziou, Kostas

    2014-05-01

    The term heliophysics refers to the physics that controls the system that is being defined by the Sun, the heliosphere and the surrounding planets. Today, we are aware that we people live within the extended atmosphere of a living star, the Sun. Although, the light that the Sun provides creates and sustains life on Earth, its variability gives birth to streams of high energetic particles and radiation which could be harmful for the human life. The magnetic field and the atmosphere of the Earth provide powerful shielding against these threats, making the Earth an oasis within the Universe were life is in place to evolve and grow. We should all keep in mind, however, that the fate of life at Earth is bounded to the way it responds to the variability of the Sun. This united system that is being analyzed through heliophysics demands the understanding of the processes that take place within and at the face of the Sun as well as the interaction of the solar plasma and the emitted radiation with the Earth and the rest of the planets. Research on heliophysics at the National Observatory of Athens focuses at the analysis of the effect of the stormy Sun to the Earth. With this respect we use data from energetic particles, recoded onboard an armada of spacecraft, trying to decode the impact of solar storms. Given the fact that heliophysics is a vital and dynamic part of our everyday life, great care is being devoted to the communication of our research results to the general public in Greece, participating at large public outreach events like the Researcher's Night and with lectures/presentations delivered regularly to a variety of audiences, but also at a worldwide scale as our team acts as the National contact point for the International Space Weather Initiative (ISWI). In this work we present vital facts of our dominant Sun, we illustrate its effect at Earth and we discuss the effectiveness of the communication techniques that have been used in order to promote

  13. H Reactor

    Data.gov (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...

  14. 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...

  15. "Confessions 7.9": What Has Athens To Do with Jerusalem?

    Science.gov (United States)

    Herzman, Ronald

    1997-01-01

    The "Confessions" of St. Augustine is important as a record of the process and results of the struggle between cultures of Athens and Jerusalem as a confrontation between classical and biblical learning. As such, it models an approach to the multicultural tensions of today. An example is given in cultural conflicts between Islam and Christianity.…

  16. Post-fledging behaviour of juveniles in the Little Owl (Athene noctua)

    DEFF Research Database (Denmark)

    Pedersen, Dorthe; Thorup, Kasper; Sunde, Peter

    2013-01-01

    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. Green Athina: A guide for applying greenery on existing apartment buildings in Athens

    NARCIS (Netherlands)

    Kaskareli, M.

    2013-01-01

    This "designers' manual" is made during the TIDO-course AR0531 Smart & Bioclimatic Design. The 'polikatikia' building type makes up for 80% of the built environment in Athens; a concrete structure multi-storey apartment building type. The aim of this manual is to provide clear information on how gr

  18. Athens Has Gone, Beijing Is Coming:More Investment, More Gold Medals

    Institute of Scientific and Technical Information of China (English)

    ZhangXueying; LuoYuanjun

    2004-01-01

    Having attended various meetings oJcelebration and citation, Cui Dalin, deputy chief of the Chinese Sports Delegation to the Athens Olympic Games, heaves a sigh of relief as he sits in his spacious office in the Training Bureau of the State General

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

    NARCIS (Netherlands)

    Issaias, P.

    2014-01-01

    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, o

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

    DEFF Research Database (Denmark)

    Tan, Kit; Tsounis, Gregory; Tsounis, Lambros

    2010-01-01

    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...

  1. 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

    2011-04-01

    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

  2. Reactor Physics

    Energy Technology Data Exchange (ETDEWEB)

    Ait Abderrahim, A

    2001-04-01

    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.

  3. Reactor safeguards

    CERN Document Server

    Russell, Charles R

    1962-01-01

    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

  4. Reactor operation

    CERN Document Server

    Shaw, J

    2013-01-01

    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

  5. Impact of solar activity on climate changes in Athens region, Greece

    CERN Document Server

    Gizani, Nectaria A B; Vatikiotis, Leonidas; Zervas, Efthimios

    2011-01-01

    The scope of this work is to study the role that the solar weather plays in terrestrial weather. For this reason we study the effect of the solar activity on the climate changes in Greece. In the current work we look for possible correlation between the solar activity data spanning the years from 1975 to 2000 and the meteorological data from two weather stations based inside the city of Athens, Greece (New Philadelphia) and in greater Athens in the north of Attica (Tatoi area). We examine the annual variations of the average values of six meteorological parameters: temperature, atmospheric pressure, direction and intensity of wind, rainfall and relative air humidity. The solar data include decade variations, within the above period, of the solar irradiance, mean sunspot number between two solar cycles, magnetic cycle influence, and solar UV driving of climate (radio flux).

  6. The impact of sea breeze under different synoptic patterns on air pollution within Athens basin.

    Science.gov (United States)

    Mavrakou, Thaleia; Philippopoulos, Kostas; Deligiorgi, Despina

    2012-09-01

    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.

  7. Impacts of air pollution and climate on materials in Athens, Greece

    Science.gov (United States)

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

    2017-01-01

    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.

  8. Reactor Neutrinos

    OpenAIRE

    Soo-Bong Kim; Thierry Lasserre; Yifang Wang

    2013-01-01

    We review the status and the results of reactor neutrino experiments. Short-baseline experiments have provided the measurement of the reactor neutrino spectrum, and their interest has been recently revived by the discovery of the reactor antineutrino anomaly, a discrepancy between the reactor neutrino flux state of the art prediction and the measurements at baselines shorter than one kilometer. Middle and long-baseline oscillation experiments at Daya Bay, Double Chooz, and RENO provided very ...

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

    Directory of Open Access Journals (Sweden)

    Roma Eleftheria S

    2010-07-01

    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.

  10. 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

    2012-01-01

    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...

  11. Black carbon measurements during winter 2013-2014 in Athens and intercomparison between different techniques

    Science.gov (United States)

    Liakakou, Eleni; Stravroulas, Jason; Roukounakis, Nikolaos; Paraskevopoulou, Despina; Fourtziou, Luciana; Psiloglou, Vassilis; Gerasopoulos, Evangelos; Sciare, Jean; Mihalopoulos, Nikolaos

    2014-05-01

    Black carbon (BC) is a particulate pollutant species emitted from the combustion of fuels, biomass burning for agricultural purposes and forest fires, with the first two anthropogenic sources being the major contributors to the atmospheric burden of BC. The presence of BC is important due to its direct and indirect physicochemical effects and its use as a tracer of burning and subsequent transport processes. Black carbon measurements took place during winter 2013 -2014 in the frame of a pollution monitoring experiment conducted at the urban site of Thissio, Athens (city center) at the premises of the National Observatory of Athens. The economic crisis in Greece and the resulting turn of Athens inhabitants to wood burning for domestic heating, has led to increased daily concentrations of BC in the range of 2-6 μg m-3, peaking at night time (15-20 μg m-3). Three different optical methods were used for the determination of BC. A Particle Soot Absorption Photometer (PSAP; Radiance Research) commercial instrument was used to monitor the light absorption coefficient (σap) at 565 nm of ambient aerosols, with 1 minute resolution. During parts of the campaign, a portable Aethalometer (AE-42; Magee Scientific) was also used to provide measurement of the aerosol BC content at 7 wavelengths over 5 minutes intervals. Exploiting the measurements at different wavelengths is was feasible to separate wood burning BC from BC related to fossil fuel. Two Multi Angle Absorption Photometers (MAAP; Thermo) were also operated as reference. Finally, aerosol samples were collected on 12-hour basis using a sequential dichotomous sampler for the sampling of PM2.5, PM2.5-10and PM10 fractions of aerosols on quartz filters, and the filters were analyzed for elemental carbon (EC) by a thermal - optical transmission technique. The main objective of the study is the intercomparison of the different BC monitoring techniques under a large range of ambient concentrations achieved due to the special

  12. Multifunctional reactors

    NARCIS (Netherlands)

    Westerterp, K.R.

    1992-01-01

    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

  13. Modeling and in situ measurements of biometeorological conditions in microenvironments within the Athens University Campus, Greece

    Science.gov (United States)

    Nastos, Panagiotis T.; Polychroni, Iliana D.

    2016-10-01

    The objective of this research is to assess and analyze the biometeorological perception in complex microenvironments in the Athens University Campus (AUC) using urban micromodels, such as RayMan. The human thermal sensation in such a place was considered of great significance due to the great gathering of student body and staff of the University. The quantification of the biometeorological conditions was succeeded by the estimation of the physiologically equivalent temperature (PET), which is a biometeorological index based on the human energy balance. We carried out, on one hand, field measurements of air temperature, relative humidity, wind speed, and global solar irradiance for different sites (building atrium, open area, and green atrium) of the examined microurban environment in order to calculate PET during January-July 2013. Additionally, on the other hand, PET modeling was performed using different sky-view factors and was compared to a reference site (meteorological station of Laboratory of Climatology and Atmospheric Environment, University of Athens). The global radiation was transferred to the examined sites with the RayMan model, which considers the sky-view factors for the adaptation of the radiation fluxes to simple and complex environments. The results of this study reveal the crucial importance of the existence of trees and green cover in a complex environment, as a factor that could be the solution to the efforts of stake holders in order to mitigate strong heat stress and improve people's living quality in urban areas.

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

    Directory of Open Access Journals (Sweden)

    Ristović Milan

    2006-01-01

    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.

  15. Modeling and in situ measurements of biometeorological conditions in microenvironments within the Athens University Campus, Greece

    Science.gov (United States)

    Nastos, Panagiotis T.; Polychroni, Iliana D.

    2016-02-01

    The objective of this research is to assess and analyze the biometeorological perception in complex microenvironments in the Athens University Campus (AUC) using urban micromodels, such as RayMan. The human thermal sensation in such a place was considered of great significance due to the great gathering of student body and staff of the University. The quantification of the biometeorological conditions was succeeded by the estimation of the physiologically equivalent temperature (PET), which is a biometeorological index based on the human energy balance. We carried out, on one hand, field measurements of air temperature, relative humidity, wind speed, and global solar irradiance for different sites (building atrium, open area, and green atrium) of the examined microurban environment in order to calculate PET during January-July 2013. Additionally, on the other hand, PET modeling was performed using different sky-view factors and was compared to a reference site (meteorological station of Laboratory of Climatology and Atmospheric Environment, University of Athens). The global radiation was transferred to the examined sites with the RayMan model, which considers the sky-view factors for the adaptation of the radiation fluxes to simple and complex environments. The results of this study reveal the crucial importance of the existence of trees and green cover in a complex environment, as a factor that could be the solution to the efforts of stake holders in order to mitigate strong heat stress and improve people's living quality in urban areas.

  16. Process' standardization and change management in higher education. The case of TEI of Athens

    Science.gov (United States)

    Chalaris, Ioannis; Chalaris, Manolis; Gritzalis, Stefanos; Belsis, Petros

    2015-02-01

    The establishment of mature operational procedures and the effort of standardizing and certifying these procedures is a particularly arduous and demanding task which requires strong commitment from management to the existing objectives, administrative stability and continuity, availability of resources, an adequate implementation team with support from all stakeholders and of course great tolerance until tangible results of the investment are shown. Ensuring these conditions, particularly in times of economic crisis, is an extremely difficult task for large organizations such as TEI of Athens where there is heterogeneity in personnel and changes in the administrative hierarchy arise plethora of additional difficulties and require an effective change management. In this work we depict the path of standardization and certification of administrative functions of TEI of Athens, with emphasis on difficulties encountered and how to address them and in particular issues of change management and the culture related to this effort. The requirement for infrastructure needed to be maintained in processes and tools process & strategic management is embodied, in order to evolve mechanisms for continuous improvement processes and storage / recovery of the resulting knowledge. The work concludes with a general design of a road map of internal audit and continuous improvement processes for a large institution of higher education.

  17. Circulation anomalies associated with winter temperature extremes in Athens during the period 1900-2004

    Energy Technology Data Exchange (ETDEWEB)

    Founda, D. [National Observatory of Athens (Greece). Inst. for Environmental Research and Sustainable Development; Loon, H. van [Colorado Univ., Boulder, CO (United States)

    2008-02-15

    We use the long series of temperature observed at the National Observatory of Athens, Greece, to examine the extremes of this element together with associated anomalies in the general circulation of the atmosphere. The 13 extreme-cold and 20 extreme-warm winters during the period 1900-2004 (equal to or below minus one standard deviation, and equal to or above plus one standard deviation respectively) had opposite pressure anomalies, mainly over the North Atlantic and Eurasia. The temperature extremes at Athens were representative of most of the Mediterranean and the Balkans, and their associated pressure anomalies were robust. The extremes of the Index of the North Atlantic Oscillation (the pressure difference between Gibraltar and Iceland) were not a good indicator of the temperature extremes in the Mediterranean. Rather the extreme temperature anomalies over the Mediterranean region are to a large extent controlled by a bipolar pattern of SLP (see level pressure) anomalies with centers over the British Isles and the Arctic. (orig.)

  18. Blood lead levels of traffic- and gasoline-exposed professionals in the city of Athens.

    Science.gov (United States)

    Kapaki, E N; Varelas, P N; Syrigou, A I; Spanaki, M V; Andreadou, E; Kakami, A E; Papageorgiou, C T

    1998-01-01

    During the past 10 y, blood lead levels in the population of Athens, Greece, have decreased steadily. This decrease has paralleled the reduction of tetraethyl lead in gasoline and the introduction of unleaded fuel. Blood lead levels and other parameters were studied in 42 gas-station employees, 47 taxi drivers, 47 bus drivers, and 36 controls, all of whom worked in Athens. The blood lead levels did not differ significantly among the four groups (5.64+/-1.7 microg/dl, 5.96+/-1.7 microg/dl, 5.88+/-1.3 microg/dl, and 5.76+/-1.7 microg/dl, respectively). Glutamic-oxaloacetic transaminase (i.e., aspartate aminotransferase) and glutamic-pyruvic transaminase (i.e., alanine aminotransferase) were elevated in gas-station employees, and the former was elevated in taxi drivers. Gas-station employees who smoked had higher blood lead levels than their nonsmoking counterparts. The absence of any difference in the blood lead levels of individuals for whom physical examinations were either normal or abnormal suggests that either lead was not the cause of increased blood lead levels or that its contribution may have been important in the past.

  19. Reactor vessel

    OpenAIRE

    Makkee, M.; Kapteijn, F.; Moulijn, J.A

    1999-01-01

    A reactor vessel (1) comprises a reactor body (2) through which channels (3) are provided whose surface comprises longitudinal inwardly directed parts (4) and is provided with a catalyst (6), as well as buffer bodies (8, 12) connected to the channels (3) on both sides of the reactor body (2) and comprising connections for supplying (9, 10, 11) and discharging (13, 14, 15) via the channels (3) gases and/or liquids entering into a reaction with each other and substances formed upon this reactio...

  20. An assessment of the stray-light in 25 years Dobson total ozone data at Athens, Greece

    Directory of Open Access Journals (Sweden)

    J. Christodoulakis

    2015-02-01

    Full Text Available In this study, we investigated the susceptibility of the Dobson spectrophotometer No. 118 to stray-light interference. In this regard, a series of total ozone content measurements were carried out in Athens, Greece for airmass values (μ extending up to μ = 5. The monochromatic-heterochromatic stray-light derived by Basher's model was used in order to evaluate the specific instrumental parameters which determine if this instrument suffers from this problem or not. The results obtained indicate that the Athens Dobson instrument appears to have an insignificant stray-light error. The comparison of the values of the same parameters measured 15 years ago with the present ones indicates the good maintenance of the Dobson spectrophotometer No. 118. This fact is of crucial importance because the variability of the daily total ozone observations collected by the Athens Dobson Station since 1989 has proved to be representative to the variability of the mean total ozone observed over the whole mid-latitude zone of the Northern Hemisphere. This stresses the point that the Athens total ozone station, being the unique Dobson station in south eastern Europe, may be assumed as a ground-truth station for the reliable conversion of the satellite radiance observations to total ozone measurements.

  1. Olympic Summer Games medals from Athens 1896 to London 2012: visual overview of each medal with a brief description

    OpenAIRE

    2015-01-01

    This document traces the evolution of the Olympic Summer Games medals, from the first Games in Athens in 1896 to those in London in 2012. Each medal is presented with a photo of its obverse and reverse, with a description of the design and the technical details available.

  2. NUCLEAR REACTOR

    Science.gov (United States)

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

    1958-01-21

    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.

  3. Reactor Neutrinos

    Directory of Open Access Journals (Sweden)

    Soo-Bong Kim

    2013-01-01

    Full Text Available We review the status and the results of reactor neutrino experiments. Short-baseline experiments have provided the measurement of the reactor neutrino spectrum, and their interest has been recently revived by the discovery of the reactor antineutrino anomaly, a discrepancy between the reactor neutrino flux state of the art prediction and the measurements at baselines shorter than one kilometer. Middle and long-baseline oscillation experiments at Daya Bay, Double Chooz, and RENO provided very recently the most precise determination of the neutrino mixing angle θ13. This paper provides an overview of the upcoming experiments and of the projects under development, including the determination of the neutrino mass hierarchy and the possible use of neutrinos for society, for nonproliferation of nuclear materials, and geophysics.

  4. Chemical Reactors.

    Science.gov (United States)

    Kenney, C. N.

    1980-01-01

    Describes a course, including content, reading list, and presentation on chemical reactors at Cambridge University, England. A brief comparison of chemical engineering education between the United States and England is also given. (JN)

  5. Reactor Neutrinos

    OpenAIRE

    Lasserre, T.; Sobel, H.W.

    2005-01-01

    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 neutrin...

  6. Using open source software for the supervision and management of the water resources system of Athens

    Science.gov (United States)

    Kozanis, S.; Christofides, A.; Efstratiadis, A.; Koukouvinos, A.; Karavokiros, G.; Mamassis, N.; Koutsoyiannis, D.; Nikolopoulos, D.

    2012-04-01

    The water supply of Athens, Greece, is implemented through a complex water resource system, extending over an area of around 4 000 km2 and including surface water and groundwater resources. It incorporates four reservoirs, 350 km of main aqueducts, 15 pumping stations, more than 100 boreholes and 5 small hydropower plants. The system is run by the Athens Water Supply and Sewerage Company (EYDAP) Over more than 10 years we have developed, information technology tools such as GIS, database and decision support systems, to assist the management of the system. Among the software components, "Enhydris", a web application for the visualization and management of geographical and hydrometeorological data, and "Hydrognomon", a data analysis and processing tool, are now free software. Enhydris is entirely based on free software technologies such as Python, Django, PostgreSQL, and JQuery. We also created http://openmeteo.org/, a web site hosting our free software products as well as a free database system devoted to the dissemination of free data. In particular, "Enhydris" is used for the management of the hydrometeorological stations and the major hydraulic structures (aqueducts, reservoirs, boreholes, etc.), as well as for the retrieval of time series, online graphs etc. For the specific needs of EYDAP, additional GIS functionality was introduced for the display and monitoring of the water supply network. This functionality is also implemented as free software and can be reused in similar projects. Except for "Hydrognomon" and "Enhydris", we have developed a number of advanced modeling applications, which are also generic-purpose tools that have been used for a long time to provide decision support for the water resource system of Athens. These are "Hydronomeas", which optimizes the operation of complex water resource systems, based on a stochastic simulation framework, "Castalia", which implements the generation of synthetic time series, and "Hydrogeios", which employs

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

    Directory of Open Access Journals (Sweden)

    Mariano José Requena

    2013-07-01

    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

  8. Patterns of criticality in the recent seismic activity in the vicinity of Athens, Greece

    Science.gov (United States)

    Dologlou, Elizabeth

    2016-04-01

    New data from the Mw 5.4 earthquake on 17 November 2014 in the vicinity of Athens and its seismic electric signal (SES) precursor confirm patterns of criticality in the pre-seismic region during the last preparatory phase. In detail, the stress drop of the main shock and the lead time of the associated SES are interconnected through a power law with an exponent a = 0.327 falling in the range of critical exponents for fracture. We note that this exponent is derived from a large amount of data and successfully passes the z-score statistical test. This fact supports the hypothesis that upon the emission of the SES the pre-focal area enters a critical stage where nonlinear dynamic processes dominate.

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

    CERN Multimedia

    ATLAS Experiment

    2012-01-01

    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. http://atlas-live-virtual-visit.web.cern.ch/atlas-live-virtual-visit/2012/Athens_filothei-2012.html

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

    Directory of Open Access Journals (Sweden)

    Holroyd, G. L.

    2011-12-01

    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.

  11. [The Codex of the Laboratory of Pharmacognosy of the University of Athens, Part. I].

    Science.gov (United States)

    Philianos, Skevos; Skaltsa, Hélène

    2015-06-01

    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.

  12. Rodents new to the diet of the western burrowing owl(athene CUNICULARIA HYPUGAEA )

    Science.gov (United States)

    Wiluford, D.L.; Woodin, M.C.; Skoruppa, M.K.; Hickman, G.C.

    2009-01-01

    The northern pygmy mouse (Baiomys taylori), fulvous harvest mouse (Reithrodontomys fulvescens), and Merriam's pocket mouse (Pemgnathus merriami) are new to the diet of the western burrowing owl (Athene cuniculana hypugaed). All three species were identified from remains in regurgitated pellets collected from roost sites of burrowing owls in southern Texas over a period of 4 winters. Together, northern pygmy mice and fulvous harvest mice represented 58% of mammals identified in 182 pellets regurgitated by western burrowing owls. Merriam's pocket mouse accounted for only 4% of identified mammalian prey. Frequency of occurrence in pellets was 16% for northern pygmv mice, 11% for fulvous harvest mice, and 3% for Merriam's pocket mice. The primary reason for absence of these species in previous studies of foods of western burrowing owls is that most were conducted in latitudes north of these southern-distributed species of mammals.

  13. The robotic and remotely controlled telescope at the University of Athens Observatory

    Science.gov (United States)

    Gazeas, K.

    2016-12-01

    A fully automatic remote telescope and dome control system has been installed at the University of Athens Observatory (UOAO) in August 2012. It was constructed in the Laboratory of Astronomy and Applied Optics of the department and incorporated the already existing automation for observations and data gathering techniques. The system proved to be reliable and functions faultlessly up to date, enabling the astronomers to observe remotely from any place, using the network. The observing nights have been increased significantly after the first year of remote operation, reaching the number of 280 observing nights per year (77% annual usage), half of which are characterized as photometric nights of highest quality. This utility favours long-term monitoring projects of blazars and long periodic variables in general.

  14. Post-fledging behaviour of juveniles in the Little Owl (Athene noctua)

    DEFF Research Database (Denmark)

    Pedersen, Dorthe; Thorup, Kasper; Sunde, Peter;

    2013-01-01

    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...... lasted 35 days (n = 6). Juveniles stayed on the natal territory 45 days (n = 5) from independence to dispersal.Half of the juveniles had dispersed by mid-September, and the other half remained on the natal territory until at leastmid-October. The home range size (minimum convex polygons) was 0.56 ± 0...... consistent with the notion that food provided by the parents decreased as juvenile foraging skills increased....

  15. Decade of the New Charter of Athens and unsustainable 2D visions of cities

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    Ćerimović Velimir Lj.

    2013-01-01

    Full Text Available This 2013 marks a decade of unsustainable 2D combinatorics and 3D visions of 21st century cities sublimation by the New Charter of Athens created in 2003. This is a good occasion to review some of its outdated and unsustainable 2D principles, the ones that have failed for entire decade to create better cities of tomorrow and are now far away from achieving it. The problem is seen in the fact that the New Charter of Athens, through unsustainable implementation of the outdated 2D terminology, sees the physical structure of a city in a proselytical and unsustainable way and accepts only high-built objects or artifacts, regarding them to be only built space and structures since they do possess walls. Therefore, the so-called visionary charter perceives the vision of the European cities of the 21st century, and the implementation of 2D terminology and 2D quasy-knowledge shows its unawareness of the fact that apart from social (local communities and high-built physical structures, cities consist of two more types of physical (3D structures, objects or artifacts having no walls. That is why its 3D vision has not been completed yet, ever since the day it was adopted in 2003, because it does not perceive and recognize low and landscape built 3D objects and artifacts. Moreover, it regards them to be the so-called non-built, the so-called free, the so-called open space. Therefore, it is certainly not unusual to note that the charter does not even mention a significant eco-reciprocity and eco-urban continuity between immanent, integrative, compatible and complementary high, low and landscape built objects or artifacts within the physical structure of cities.

  16. Past, present and future of passive homes in solar village 3, Athens

    Science.gov (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.

  17. Prevalence of hepatitis B and C markers among refugees in Athens

    Institute of Scientific and Technical Information of China (English)

    Anastasios Roussos; Constantin Goritsas; Thomas Pappas; Maria Spanaki; Panagiota Papadaki; Angeliki Ferti

    2003-01-01

    AIM: To assess the prevalence of hepatitis B and C serological markers in a population of refugees living in Athens.METHODS: One hundred and thirty refugees (81 males and 49 females, mean age ±SD: 31.7±8 years) were included in the study. The hepatitis B virus surface antigen (HBsAg),the hepatitis B virus core antibody (anti-HBc) and the hepatitis C virus antibody (anti-HCV) were detected using a third-generation immunoassay.RESULTS: Twenty individuals (15.4%) were HBsAg positive and 69 (53.1%) were anti-HBc positive. The prevalence of HBsAg and anti-HBc was higher among refugees from Albania and Asia (statistical significant difference, P<0.008 and P<0.001 respectively). The prevalence of these markers was found irrelevant to age or sex. Anti-HCV was detected in the serum of 3 individuals (2.3 %). No differences among age, sex or ethnicity regarding anti-HCV prevalence were found.CONCLUSION: It can be concluded that refugees living in Athens are an immigrant population characterized by a high incidence of HBV infection. The prevalence of HBV markers is higher among refugees from Albania and Asia. It is therefore believed that the adherence to general precautions and the initiation of HBV vaccination programs will be necessary in the future, especially in these communities.Although the prevalence of HCV infection seems to be relatively low, extended epidemiological surveys are needed to provide valid results.

  18. The use of nutritional supplements among recreational athletes in Athens, Greece.

    Science.gov (United States)

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

    2011-10-01

    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 < .001), level of education (χ2 = 14.1, df = 3, p < .001), and profession (χ2 = 11.4, df = 4, p = .022) were associated with the subjects' decision to consume nutritional supplements. Most (67.1%) purchased products from health food stores. Only 17.1% had consulted a physician or nutritionist, and one third were aware of the relevant legislation. Two preparations were detected containing synthetic anabolic 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.

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

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    Komatina Predrag

    2009-01-01

    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

  20. Sonochemical Reactors.

    Science.gov (United States)

    Gogate, Parag R; Patil, Pankaj N

    2016-10-01

    Sonochemical reactors are based on the generation of cavitational events using ultrasound and offer immense potential for the intensification of physical and chemical processing applications. The present work presents a critical analysis of the underlying mechanisms for intensification, available reactor configurations and overview of the different applications exploited successfully, though mostly at laboratory scales. Guidelines have also been presented for optimum selection of the important operating parameters (frequency and intensity of irradiation, temperature and liquid physicochemical properties) as well as the geometric parameters (type of reactor configuration and the number/position of the transducers) so as to maximize the process intensification benefits. The key areas for future work so as to transform the successful technique at laboratory/pilot scale into commercial technology have also been discussed. Overall, it has been established that there is immense potential for sonochemical reactors for process intensification leading to greener processing and economic benefits. Combined efforts from a wide range of disciplines such as material science, physics, chemistry and chemical engineers are required to harness the benefits at commercial scale operation.

  1. Geodetic evidence for passive control of a major Miocene tectonic boundary on the contemporary deformation field of Athens (Greece

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    Michael Foumelis

    2014-02-01

    Full Text Available A GPS-derived velocity field is presented from a dense geodetic network (~5km distance between stations established in the broader area of Athens. It shows significant local variations of strain rates across a major inactive tectonic boundary separating metamorphic and non-metamorphic geotectonic units. The southeastern part of Athens plain displays negligible deformation rates, whereas towards the northwestern part higher strain rates are observed, indicating the control of the inactive tectonic boundary on the contemporary deformation field of the region. These findings are in agreement with previous geological observations, however, due to the dense local GPS network it was fatherly possible to localize and quantify the effect of such a major inherited tectonic feature on the deformation pattern of the area.

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

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    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.

  3. Monitoring the urban expansion of Athens using remote sensing and GIS techniques in the last 35 years

    Science.gov (United States)

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

    2005-10-01

    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.

  4. PM1 levels are related to CO concentrations and health impacts in the city Athens Greece

    Science.gov (United States)

    Grigoropoulos, Konstantinos; Polichetti, Giuliano; Ferentinos, George; Tselentis, Vasilios; Nastos, Panagiotis; Xatzioakeimidis, Konstantinos; Dimas, Konstantinos; Kalabokis, Vasilios; Gialouris, Athanasios

    2010-05-01

    Senekas, as early as 60 A.D., was the first to refer to air pollution and the possibility of imposing restrictions in Rome. In 1307, during the reign of Edward I, legislation was introduced to prevent the use of sea coal in kilns and limeburners in London. In the 19th century the first problems arising from elevated levels of smoke in cities appear. By 1930, Pittsburgh Pennsylvania suffered from heavy smoke pollution and the 1952 London smog episode stands out as one of the worst pollution disasters given the number of people who died as a result. Mega city pollution has become a serious problem to human health and in an effort to analyze and mitigate this threat, the European and worldwide scientific communities are, at present, placing considerable time, effort and resources in the field. It is well known that vehicle related NOx and CO emissions represent the main public health hazard (cardiovascular and respiratory syndromes) in the main industrialized cities of Europe with high traffic volumes. The objective of this study is to analyze the spatial distribution of PM1, CO and the related health impacts within the greater Athens area (GAA). Several portable and ground based detectors were employed for the PM and CO measurements, capable of detecting CO levels in the ambient environment, up to 1000 ppm. Sampling took place on road sidewalks at a specified hour every morning to coincide with the peak in vehicle traffic. Controls were performed with no traffic and compared to normal traffic days and days with extreme traffic congestion, which included PM and CO concentration measurements. In addition, in order to monitor potentially related health impacts, daily admissions to the Emergency Departments of the Social Security Institute and Regional Hospitals of Athens were recorded. Results demonstrate a significant correlation between both PM1 and CO and particulate matter symptomatology, such as dispnea, fatigue, headache, dacryrrea and dry cough. These findings

  5. Radioactive pollution in Athens, Greece due to the Fukushima nuclear accident.

    Science.gov (United States)

    Kritidis, P; Florou, H; Eleftheriadis, K; Evangeliou, N; Gini, M; Sotiropoulou, M; Diapouli, E; Vratolis, S

    2012-12-01

    As a result of the nuclear accident in Fukushima Dai-ichi power plant, which started on March 11, 2011, radioactive pollutants were transferred by air masses to various regions of the Northern hemisphere, including Europe. Very low concentrations of (131)I, (137)Cs and (134)Cs in airborne particulate matter were measured in Athens, Greece during the period of March 24 to April 28, 2011. The maximum air concentration of (131)I was measured on April 6, 2011 and equaled 490 ± 35 μBq m(-3). The maximum values of the two cesium isotopes were measured on the same day and equaled 180 ± 40 μBq m(-3) for (137)Cs and 160 ± 30 μBq m(-3) for (134)Cs. The average activity ratio of (131)I/(137)Cs in air was 3.0 ± 0.5, while the corresponding ratio of (137)Cs/(134)Cs equaled 1.1 ± 0.3. No artificial radionuclides could be detected in air after April 28, 2011. Traces of (131)I as a result of radioactive deposition were measured in grass, soil, sheep milk and meat. The total deposition of (131)I (dry + wet) was 34 ± 4 Bq m(-2), and of (137)Cs was less than 10 Bq m(-2). The maximum concentration of (131)I in grass was 2.1 ± 0.4 Bg kg(-1), while (134)Cs was not detected. The maximum concentrations of (131)I and (137)Cs in sheep milk were 1.7 ± 0.16 Bq kg(-1) and 0.6 ± 0.12 Bq kg(-1) respectively. Concentrations of (131)I up to 1.3 ± 0.2 Bq kg(-1) were measured in sheep meat. Traces of (131)I were found in a number of soil samples. The radiological impact of the Fukushima nuclear accident in Athens region was practically negligible, especially as compared to that of the Chernobyl accident and also to that of natural radioactivity.

  6. Shakespeare and Middleton’s Co-Authorship of Timon of Athens

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    Eilidh Kane

    2016-03-01

    Full Text Available The essay focuses on Shakespeare’s collaboration with Thomas Middleton on Timon of Athens (1605-1606. It provides new evidence concerning the patterns of imagery in the play and argues that these support the authorial divisions established by earlier attribution studies. Beyond the issue of ‘who wrote what’ are questions about how Shakespeare co-wrote with Middleton. Previous analysis of the play has suggested that Timon was co-written consecutively, Shakespeare first, Middleton second. However, it is argued here that a mixture of consecutive and simultaneous co-writing would better explain the play as it stands. In the course of making the case, the essay reasserts the value of attribution evidence to the study of collaboration. Middleton’s skill in writing cynical urban scenes for his city comedies is often cited as the reason why he and Shakespeare worked together on Timon; and it is argued that Middleton’s early pamphlets should also be considered as evidence of his ability to satirise greed, and therefore as a reason why he was valuable to Shakespeare as a collaborator.

  7. Possible Geomagnetic and Environmental Symptoms in the Area of Athens During the Solar Cycle No 22

    Science.gov (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

  8. Monitoring the effect of urban green areas on the heat island in Athens.

    Science.gov (United States)

    Zoulia, I; Santamouris, M; Dimoudi, A

    2009-09-01

    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.

  9. A decision support system for the management of the water resource system of Athens

    Science.gov (United States)

    Koutsoyiannis, D.; Karavokiros, G.; Efstratiadis, A.; Mamassis, N.; Koukouvinos, A.; Christofides, A.

    The main components of a decision support system (DSS) developed to support the management of the water resource system of Athens are presented. The DSS includes information systems that perform data acquisition, management and visualisation, and models that perform simulation and optimisation of the hydrosystem. The models, which are the focus of the present work, are organised into two main modules. The first one is a stochastic hydrological simulator, which, based on the analysis of historical hydrological data, generates simulations and forecasts of the hydrosystem inputs. The second one allows the detailed study of the hydrosystem under alternative management policies implementing the parameterisation-simulation-optimisation methodology. The mathematical framework of this new methodology performs the allocation of the water resources to the different system components, keeping the number of control variables small and thus reducing the computational effort, even for a complex hydrosystem like the one under study. Multiple, competitive targets and constraints with different priorities can be set, which are concerned among others, with the system reliability and risk, the overall average operational cost and the overall guaranteed yield of the system. The DSS is now in the final stage of its development and its results, some of which are summarised in the paper, have been utilised to support the new masterplan of the hydrosystem management.

  10. Bioavailability and health risk assessment of potentially toxic elements in Thriasio Plain, near Athens, Greece.

    Science.gov (United States)

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

    2017-04-01

    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).

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

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    K. Mazi

    2006-01-01

    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.

  12. 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: agodel@geol.uoa.gr [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)

    2011-03-15

    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.

  13. Validation of LIRIC aerosol concentration retrievals using airborne measurements during a biomass burning episode over Athens

    Science.gov (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

    2017-01-01

    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.

  14. Biometry based ageing of nestling Indian Spotted Owlets (Athene brama brama

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    Satish Pande

    2011-10-01

    Full Text Available Biometric analysis helps in sex differentiation, understanding development and for studies of avian biology such as foraging ecology, evolutionary ecology, and survivorship. We suggest that biometry can also be a reliable, practical and inexpensive tool to determine the age of nestlings in the field by non-invasive methods. As an example we studied the biometry of wing, culmen, talon, tarsus and body mass of nestling southern Indian Spotted Owlets (Athene brama brama. Based on the growth pattern analysis using logistic growth model, discriminant analysis and CHAID (Chi-squared Automatic Interaction Detection based decision tree, we show that biometry of nestling Spotted Owlets is an easy, reliable and inexpensive method to determine nestling age and to assess growth rate and relative nutritional status. These biometric parameters also allow us to predict their ability to initiate first flight from the nest site. This method is described here for the first time and we postulate that such charts can be devised for other avian species as well, so as to assist conservation biologists and bird rescuers.

  15. Vaccination and Malaria Prevention among International Travelers Departing from Athens International Airport to African Destinations.

    Science.gov (United States)

    Pavli, Androula; Spilioti, Athina; Smeti, Paraskevi; Patrinos, Stavros; Maltezou, Helena C

    2014-01-01

    Background. International travel to Africa has grown dramatically over the last decade along with an increasing need to understand the health issues for travelers. The current survey aimed to assess vaccination and malaria prevention of travelers visiting Africa. Methods. A questionnaire-based survey was conducted from of November 1, 2011 to of April 30, 2013 at Athens International Airport. Results. A total of 360 travelers were studied; 68% were men. Their mean age was 39.9 years. Previous travel to tropical countries was reported by 71.9% of them. Most frequent destination was sub-Saharan Africa (60%). Most of them traveled for ≥1 month (62%). The main reason for travel was work (39.7%). Only 47% sought pretravel consultation. Hepatitis A, typhoid, and meningococcal vaccines were administered to 49.8%, 28%, and 26.6%, respectively, and malaria chemoprophylaxis to 66.8% of those who visited sub-Saharan Africa. A history of previous travel to a tropical country, elementary level of education, and traveling for visiting friends and relatives, and for short duration were significant determinants for not pursuing pretravel consultation. Conclusions. The current survey revealed important inadequacies in vaccine and malaria prophylaxis of travelers departing to Africa. Educational tools should be developed in order to improve awareness of travelers to risk destinations.

  16. Vaccination and Malaria Prevention among International Travelers Departing from Athens International Airport to African Destinations

    Directory of Open Access Journals (Sweden)

    Androula Pavli

    2014-01-01

    Full Text Available Background. International travel to Africa has grown dramatically over the last decade along with an increasing need to understand the health issues for travelers. The current survey aimed to assess vaccination and malaria prevention of travelers visiting Africa. Methods. A questionnaire-based survey was conducted from of November 1, 2011 to of April 30, 2013 at Athens International Airport. Results. A total of 360 travelers were studied; 68% were men. Their mean age was 39.9 years. Previous travel to tropical countries was reported by 71.9% of them. Most frequent destination was sub-Saharan Africa (60%. Most of them traveled for ≥1 month (62%. The main reason for travel was work (39.7%. Only 47% sought pretravel consultation. Hepatitis A, typhoid, and meningococcal vaccines were administered to 49.8%, 28%, and 26.6%, respectively, and malaria chemoprophylaxis to 66.8% of those who visited sub-Saharan Africa. A history of previous travel to a tropical country, elementary level of education, and traveling for visiting friends and relatives, and for short duration were significant determinants for not pursuing pretravel consultation. Conclusions. The current survey revealed important inadequacies in vaccine and malaria prophylaxis of travelers departing to Africa. Educational tools should be developed in order to improve awareness of travelers to risk destinations.

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

    Directory of Open Access Journals (Sweden)

    THEODOROS GEORGIADIS

    2006-01-01

    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.

  18. Anthropological demography in Europe: Methodological lessons from a comparative ethnographic study in Athens and London

    Directory of Open Access Journals (Sweden)

    Katerina Georgiadis

    2007-07-01

    Full Text Available This paper offers a descriptive account of the methods used to conduct a comparative ethnographic study of below-replacement fertility in Athens, Greece and London, UK. It argues that in order for anthropology and demography to forge a closer relationship each discipline first needs to gain a deeper appreciation of the other's methodological perspectives. The following discussion presents the key anthropological approaches employed to realize a research project on low fertility in Europe, and provides justification for their use. While the practices described in this paper might be familiar to anthropologists and qualitative demographers, they are less well-known in the wider demographic community. Those convinced of the benefits of the ethnographic approach to the study of fertility are also invited to consider the specific obstacles encountered in the course of this enquiry. This paper reaches the following methodological conclusions: 1 Findings from two ethnographic studies of low fertility can be compared and generalised if such concepts as 'comparison' and 'generalisation' are understood in the anthropological sense. 2 Those investigating fertility in Europe must remain critical of their position relative to their study participants, even if they are undertaking research 'at home'. 3 Exploring attitudes towards reproduction and experiences of family-formation in an urban setting presents unique challenges as does 4 asking women about their childbearing beliefs and practices. 5 Analysing press perspectives on low fertility must involve treating media representations as 'discourse' and 6 qualitative studies are invaluable to the low fertility debate because of their thematic contributions.

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

    Directory of Open Access Journals (Sweden)

    C. Tzanis

    2011-12-01

    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.

  20. Attitudes on euthanasia and physician-assisted suicide among medical students in Athens.

    Science.gov (United States)

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

    2009-10-01

    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.

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

    Science.gov (United States)

    Theophanides, Mike; Anastassopoulou, Jane

    2009-07-01

    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.

  2. MAX-DOAS observation of HCHO and CHOCHO over Athens and Nairobi

    Science.gov (United States)

    Alvarado, Leonardo; Richter, Andreas; Peters, Enno; Wittrock, Folkard; Burrows, John; Vrekoussis, Mihalis; Gratsea, Myrto; Gerasopoulos, Vangelis

    2014-05-01

    Formaldehyde (HCHO) is the most abundant among the carbonyls, while glyoxal (CHOCHO) is the most predominant of the alpha dicarbonyls in the atmosphere. Both species originate from a wide range of natural and anthropogenic sources. In addition, HCHO and CHOCHO are being emitted during biomass burning and the emitted amounts depending on the type of biomass burned as well as the temperatures of the fire. Due to their short lifetime, CHOCHO and HCHO are used as indicators of photochemical activity and intermediate products of the process of degradation of VOCs. While sources and chemistry of CHOCHO and HCHO are similar in many respects, the variation in production efficiency for different sources can be used to better constrain source attribution of VOCs e.g. by analysing the ratio of HCHO to CHOCHO. Atmospheric HCHO and CHOCHO columns can be determined by remote sensing using the Differential Optical Absorption Spectroscopy (DOAS) method. The DOAS method allows the determination of atmospheric amounts of trace gases with narrow absorption bands in the ultraviolet and visible. In this study we report the first HCHO and CHOCHO results from the MAX-DOAS stations in Athens (38N, 24E) and Nairobi (1S, 36E) which are part of the Bremian DOAS Network for Atmospheric Measurements (BREDOM). The results show higher values of CHOCHO and HCHO in summer than in the winter season. Moreover, analyses of the ratio of HCHO to CHOCHO are presented as well as preliminary comparison of CHOCHO columns with satellite data from GOME-2 and OMI.

  3. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T. (Inventor); Sahimi, Muhammad (Inventor); Fayyaz-Najafi, Babak (Inventor); Harale, Aadesh (Inventor); Park, Byoung-Gi (Inventor); Liu, Paul K. T. (Inventor)

    2011-01-01

    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.

  4. D and DR Reactors

    Data.gov (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...

  5. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T.; Sahimi, Muhammad; Fayyaz-Najafi, Babak; Harale, Aadesh; Park, Byoung-Gi; Liu, Paul K. T.

    2011-03-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Mavromichalaki

    2005-11-01

    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.

  7. Retrieval of aerosol optical depth in the visible range with a Brewer spectrophotometer in Athens

    Science.gov (United States)

    Diémoz, Henri; Eleftheratos, Kostas; Kazadzis, Stelios; Amiridis, Vassilis; Zerefos, Christos S.

    2016-04-01

    A MkIV Brewer spectrophotometer has been operating in Athens since 2004. Direct-sun measurements originally scheduled for nitrogen dioxide retrievals were reprocessed to provide aerosol optical depths (AODs) at a wavelength of about 440 nm. A novel retrieval algorithm was specifically developed and the resulting AODs were compared to those obtained from a collocated Cimel filter radiometer belonging to the Aerosol Robotic Network (AERONET). The series are perfectly correlated, with Pearson's correlation coefficients being as large as 0.996 and with 90 % of AOD deviations between the two instruments being within the World Meteorological Organisation (WMO) traceability limits. In order to reach such a high agreement, several instrumental factors impacting the quality of the Brewer retrievals must be taken into account, including sensitivity to the internal temperature, and the state of the external optics and pointing accuracy must be carefully checked. Furthermore, the long-term radiometric stability of the Brewer was investigated and the performances of in situ Langley extrapolations as a way to track the absolute calibration of the Brewer were assessed. Other sources of error, such as slight shifts of the wavelength scale, are discussed and some recommendations to Brewer operators are drawn. Although MkIV Brewers are rarely employed to retrieve AODs in the visible range, they represent a key source of information about aerosol changes in the past three decades and a potential worldwide network for present and future coordinated AOD measurements. Moreover, a better understanding of the AOD retrieval at visible wavelengths will also contribute in improving similar techniques in the more challenging UV range.

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

    Directory of Open Access Journals (Sweden)

    Reviewed by Antonis LIONARAKIS

    2008-01-01

    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

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

    Science.gov (United States)

    Argyraki, Ariadne; Kelepertzis, Efstratios

    2014-06-01

    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.

  10. Urban vegetation cover extraction from hyperspectral imagery and geographic information system spatial analysis techniques: case of Athens, Greece

    Science.gov (United States)

    Petropoulos, George P.; Kalivas, Dionissios P.; Georgopoulou, Iro A.; Srivastava, Prashant K.

    2015-01-01

    The present study aimed at evaluating the performance of two different pixel-based classifiers [spectral angle mapper (SAM) and support vector machines (SVMs)] in discriminating different land-cover classes in a typical urban setting, focusing particularly on urban vegetation cover by utilizing hyperspectral (EO-1 Hyperion) data. As a case study, the city of Athens, Greece, was used. Validation of urban vegetation predictions was based on the error matrix statistics. Additionally, the final urban vegetation cover maps were compared at a municipality level against reference urban vegetation cover estimates derived from the digitization of very high-resolution imagery. To ensure consistency and comparability of the results, the same training and validation points dataset were used to compare the different classifiers. The results showed that SVMs outperformed SAM in terms of both classification and urban vegetation cover mapping with an overall accuracy of 86.53% and Kappa coefficient 0.823, whereas for SAM classification, the accuracy statistics obtained were 75.13% and 0.673, respectively. Our results confirmed the ability of both techniques, when combined with Hyperion imagery, to extract urban vegetation cover for the case of a densely populated city with complex urban features, such as Athens. Our findings offer significant information at the local scale as regards to the presence of open green spaces in the urban environment of Athens. Such information is vital for successful infrastructure development, urban landscape planning, and improvement of urban environment. More widely, this study also contributes significantly toward an objective assessment of Hyperion in detecting and mapping urban vegetation cover.

  11. 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

    2009-09-01

    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.

  12. Newcastle disease virus in little owls (Athene noctua) and African penguins (Spheniscus demersus) in an Israeli zoo.

    Science.gov (United States)

    Haddas, R; Meir, R; Perk, S; Horowitz, I; Lapin, E; Rosenbluth, E; Lublin, A

    2014-12-01

    Newcastle disease is a contagious and often fatal disease, capable of affecting all species of birds. A velogenic Newcastle disease virus (vNDV) outbreak occurred in an Israeli zoo, in which Little owls (Athene noctua) and African penguins (Spheniscus demersus) were found positive for presence of NDV. Some of them have died. The diagnostic process included: post-mortem examination, histopathology, real-time RT-PCR assay, virus isolation, serology, intracerebral pathogenicity index and phylogenetic analysis. A vNDV was diagnosed and found to be closely related to isolates from vNDV outbreaks that occurred in commercial poultry flocks during 2011. All isolates were classified as lineage 5d.

  13. 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

    2012-01-01

    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...

  14. Reactor and method of operation

    Science.gov (United States)

    Wheeler, John A.

    1976-08-10

    A nuclear reactor having a flattened reactor activity curve across the reactor includes fuel extending over a lesser portion of the fuel channels in the central portion of the reactor than in the remainder of the reactor.

  15. Black Carbon Particle Number Distribution Measurements during the ATHENS-2013 Winter Campaign

    Science.gov (United States)

    Gkatzelis, Georgios; Papanastasiou, Dimitris; Florou, Kalliopi; Kaltsonoudis, Christos; Louvaris, Eyaggelos; Bezentakos, Spiridon; Biskos, Georgios; Pandis, Spuros

    2014-05-01

    Black Carbon (BC) particles emitted by anthropogenic sources play an important role both in climate change and in air quality degradation. Open burning in forests and savannas, combustion of diesel and solid fuels for cooking and heating in homes represent the majority of BC emissions. Earlier work has focused on the BC atmospheric direct radiative forcing that is mostly related to its mass concentration and optical properties of the corresponding particles. A variety of measurement techniques are used to measure the mass concentration of BC by taking advantage of its optical or physical properties. Moreover, the carbonaceous particles containing BC are also important for the indirect forcing of climate. This effect is mostly related to the number concentration of BC particles. The number distribution of BC particles especially below 100 nm is quite uncertain due to limitations of the existing measurement techniques. In this work we employed a thermodenuder-based method as an approach for the measurement of the BC number distribution. More specifically, we combined a thermodenuder (TD) operating at temperatures up to 300 ° C, with a Scanning Mobility Particle Sizer (SMPS) and a High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF AMS). Aerosol size and composition measurements were carried out both at ambient and at elevated TD temperatures in Athens field campaign during January and February of 2013. In parallel, a Multi-Angle Absorption Photometer (MAAP) provided information about the BC mass concentration while a Hygroscopic Tandem Differential Mobility Analyzer (HTDMA) measured the mixing state and the hygroscopicity of the particles as a function of their size. These measurements were then combined to estimate the number concentration of BC particles. Our analysis focused on different periods during the study. During some of them one source dominated the carbonaceous aerosol concentration. Such periods included rush hour traffic, nighttime wood

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

    Directory of Open Access Journals (Sweden)

    Nikos Kaskampas

    2011-12-01

    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

  17. Patients' perception of quality of pre-operative informed consent in athens, Greece: a pilot study.

    Directory of Open Access Journals (Sweden)

    Matthew E Falagas

    Full Text Available BACKGROUND: We sought to perform a study to record and evaluate patients' views of the way surgeons communicate informed consent (IC in Greece. METHODOLOGY/PRINCIPAL FINDINGS: A prospective pilot study was carried out in Athens from 9/2007 to 4/2008. The study sample was extracted from patients, operated by eight different surgeons, who volunteered to fill in a post-surgery self-report questionnaire on IC. A composite delivered information index and a patient-physician relationship index were constructed for the purposes of the analysis. In total, 77 patients (42 males volunteered to respond to the questionnaire. The delivered information index scores ranged from 3 to 10, the mean score was 8, and the standard deviation (SD was 1.9. All patients were aware of their underlying diagnosis and reason for surgery. However, a considerable proportion of the respondents (14.3% achieved a score below or equal to 5. The patient-physician relationship scores ranged from 0 to 20, the mean score was 16 and the standard deviation (SD was 4.3. The better the patient-physician relationship, the more information was finally delivered to the patient from the physician (Spearman's rank-order correlation coefficient was 0.4 and p<0.001. Delivered information index was significantly higher among participants who comprehended the right to informed consent, compared to participants who did not (p<0.001, and among participants who were given information regarding other possible therapeutic options (p = 0.001. 43% of the respondents answered that less than 10 minutes were spent on the consent process, 58.4% of patients stated that they had not been informed about other possible therapeutic choices and 28.6% did not really comprehend their legal rights to IC. CONCLUSIONS: Despite the inherent limitations and the small sample size that do not permit to draw any firm conclusions, results indicate that a successful IC process may be associated with specific elements such as

  18. 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: adrian.covaci@ua.ac.be; 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)

    2005-07-15

    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

  19. Averroës in The school of Athens: a Renaissance man and his contribution to Western thought and neuroscience.

    Science.gov (United States)

    Belen, Deniz; Bolay, Hayrunnisa

    2009-02-01

    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.

  20. “One good man in a corrupt ancient society”: The Steward in Shakespeare’s Timon of Athens

    Directory of Open Access Journals (Sweden)

    Florence Toh Haw Ching

    2012-07-01

    Full Text Available Within the master-servant relationships of the hierarchical Renaissance era, loyalty is often assumed as a common and expected attribute. However, the present study reveals this assumption as a misconception. From the evidence gathered, the paper highlights the declining virtue of loyalty particularly among the servant class of the Elizabethan era. Despite that, the Steward in Shakespeare’s Timon of Athens (1605 portrayed commendable examples and extent of loyalty towards his master, Timon. This represents a stark contrast to the selfish and disloyal community of Shakespeare’s seventeenth-century England. Through discussions of the scenes in which the servant character displayed acts of loyalty towards the protagonist, the paper emphasizes the significant contribution of the selected character in preserving the well-being of his master.  It is hoped that through an understanding of the loyalty shown by the Steward towards his master, Timon, the study will heighten understanding of Shakespeare’s servant characters leading to further appreciation of the dramatist’s work, Timon of Athens. Keywords: Elizabethan society, loyalty, master-servant relationship, Renaissance play

  1. FROM THE "NATIONAL" TO THE POLITICAL CONSCIOUSNESS IN ATHENS OF THE 6TH CENTURY BCE, AND THE EMERGENCE OF DEMOCRACY

    Directory of Open Access Journals (Sweden)

    Eleni Krikona

    2016-04-01

    Full Text Available This paper addresses the construction of a "national" identity of the Athenian inhabitants during the tyrannical governance of Peisistratos and his sons (561/0-511/0 BCE mainly through a series of religious practices, such as the transfer of cults from the rural areas to the city (asty of Athens, the reorganization of the Panathenaia, the establishment of the City Dionysia, etc. The present paper investigates how this developed "national" consciousness in the late 6th century, in the sense of the citizens’ nationalization within the borders of the Athenian city-state, could enable the political unification of Attica and the emergence of Democracy, taking into account the constitutional reforms of Kleisthenes the Alcmeonid, after the expulsion of the Peisistratidai. This paper focuses on the interpretation of the concept of political equality and the formation of a political identity of the Athenians in the late 6th century onwards, two notions which are treated here as very closely integrated. It was that political consciousness, following the constitutional changes of Kleisthenes, which led the Athenians to their first great military victories in the early 5th century over the Persians. These victories, which indisputably confirmed the strength of the constitution, will be brought, in short, into discussion in order to clarify the transition of Athens from the narrow borders of an archaic city-state to the rise of its naval empire in the "golden" 5th century via the newly established Democracy.  

  2. The Economic Crisis in Greece and Its Impact on the Seasonality of Suicides in the Athens Greater Area

    Science.gov (United States)

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

    2017-01-01

    Objective 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. Methods 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. Results 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). Conclusion 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). PMID:28096870

  3. Prevalence of attention deficit hyperactivity disorder in schoolchildren in Athens, Greece. Association of ADHD subtypes with social and academic impairment.

    Science.gov (United States)

    Skounti, M; Giannoukas, S; Dimitriou, E; Nikolopoulou, S; Linardakis, E; Philalithis, A

    2010-11-01

    The aim of this study was to explore the prevalence of attention deficit hyperactivity disorder (ADHD) and social and academic impairment in 6- to 11-year-old children residents of Athens, Greece. We screened 603 elementary schoolchildren following grades first to sixth. A two-stage screening process was employed including a standardized ADHD test for teachers and the Teacher Report Form (TRF). Among the 603 children, 36 (6.0%) met the study criteria for ADHD. The estimated prevalence was 8% for boys and 3.8% for girls. The most prevalent subtype of ADHD was the combined type (3.8%), followed by the ADHD inattentive (1.7%) and the ADHD hyperactive-impulsive type (0.5%). The ADHD-combined type was strongly associated with clinical impairment in both areas of functioning (academic and social), where the ADHD inattentive subtype was found to be strongly associated with academic problems. The ADHD hyperactive-impulsive type was the less prevalent and the less impaired subtype in this study. None of the 36 children had been previously diagnosed as having ADHD or other primary disorder. In conclusion, the prevalence of ADHD among schoolchildren in Athens and the risk factors were found to be comparable to those reported in other countries worldwide. Additionally, impairment in social and academic functioning was strongly associated with the subtypes of the disorder.

  4. Interdecadal variations and trends of the Urban Heat Island in Athens (Greece) and its response to heat waves

    Science.gov (United States)

    Founda, D.; Pierros, F.; Petrakis, M.; Zerefos, C.

    2015-07-01

    The study explores the interdecadal and seasonal variability of the urban heat island (UHI) intensity in the city of Athens. Daily air temperature data from a set of urban and surrounding non urban stations over the period 1970-2004 were used. Nighttime and daytime heat island revealed different characteristics as regards the mean amplitude, seasonal variability and temporal variation and trends. The difference of the annual mean air temperature between urban and rural stations exhibited a progressive statistically significant increase over the studied period, with rates equal to + 0.2 °C/decade. A gradual and constant increase of the daytime UHI intensity was detected, in contrast to the nighttime UHI intensity which increases only in summer, after the mid 1980s. UHI phenomenon was found to be related to higher increasing rates of hot days frequency at the urban stations. It was found that the interaction between heat waves and heat island in Athens, results to pronounced amplification of nocturnal UHI intensity under exceptionally hot weather.

  5. Particulate matter (PM2.5) and carbon monoxide from secondhand smoke outside bars and restaurants in downtown Athens, Georgia.

    Science.gov (United States)

    St Helen, Gideon; Hall, Daniel B; Kudon, Louis H; Pearce, John; Baptiste, Shanece; Ferguson, Sylvia; Green, Tiffany; Naeher, Luke P

    2011-10-01

    In the study described in this article, the authors' objective was to measure particles waiting areas and patios of restaurants and bars in downtown Athens, Georgia, where indoor smoking is banned. The authors also wanted to investigate whether the measured concentrations are directly associated with the number of cigarettes lit in these settings. Real-time PM2.5 and CO were monitored on four summer weekend afternoons/evenings in outdoor waiting areas or patios at five locations in Athens. In addition, smokers and pedestrians present or passing and motorized vehicles passing each sampling location were counted. PM2.5 levels were significantly higher than levels at the control location (all p-values > .001). Carbon monoxide levels outside the restaurant and bar sites did not differ significantly from the control. The results of the authors' study indicate that (1) secondhand smoke (SHS) leads to significant increases in PM2.5 outside of restaurants and bars; and (2) although CO can be used as a proxy for SHS in these outdoor environments, its levels remain relatively low.

  6. Logic and theory of algorithms: 4th Conference on Computability in Europe, CiE 2008, Athens, Greece, June 15-20, 2008: Proceedings

    NARCIS (Netherlands)

    Beckman, A.; Dimitracopoulos, C.; Löwe, B.

    2008-01-01

    This book constitutes the refereed proceedings of the 4th International Conference on Computability in Europe, CiE 2008, held in Athens, Greece, in June 2008. The 36 revised full papers presented together with 25 invited tutorials and lectures were carefully reviewed and selected from 108 submission

  7. 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, J.M.; Brink, van den N.W.

    2012-01-01

    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 s

  8. 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

    2009-01-01

    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

  9. Reactor Physics Programme

    Energy Technology Data Exchange (ETDEWEB)

    De Raedt, C

    2000-07-01

    The Reactor Physics and 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 on reactor fuel. This expertise is applied within the Reactor Physics and MYRRHA Research 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. Progress and achievements in 1999 in the following areas are reported on: (1) investigations on the use of military plutonium in commercial power reactors; (2) neutron and gamma calculations performed for BR-2 and for other reactors; (3) the updating of neutron and gamma cross-section libraries; (4) the implementation of reactor codes; (6) the management of the UNIX workstations; and (6) fuel cycle studies.

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

    Science.gov (United States)

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

    2016-08-01

    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. Design, Implementation and Assessment of Videoconferencing Sessions in Earth and Life Sciences: The Case of the Agricultural University of Athens

    Directory of Open Access Journals (Sweden)

    George Papadopoulos

    2013-04-01

    Full Text Available In this paper we present the methodology employed in the Agricultural University of Athens for the delivery of specific courses with the use of video conferencing technology. Earth and Life Science higher education courses (agricultural, environmental and biomedical courses present specific requirements relevant to the exposure of the students to practical issues, and the exchange of expertise. The employment of video conferencing seems be a valuable solution for addressing a number of these requirements. We describe these requirements as they emerged from our study, and present the implementation of video conferencing sessions (design, application, and assessment. Through this paper we aim at describing examples of meaningful employment of video conferencing, particularly in higher education, share the positive and negative aspects of our approach, and provide insights for similar interventions in education and training.

  12. Transits of Venus and Solar diameter measures from ground: method and results from Athens (2004) and Huairou (2012)

    CERN Document Server

    Sigismondi, Costantino; Wang, Xiaofan; Xie, Wenbin; Carinci, Massimo; Mimmo, Alessio

    2015-01-01

    The variation of the solar diameter in time and in position angle has implications in astrophysics and in general relativity, as the long series of studies attest. The Transits of Venus in 2004 and 2012 have been carefully studied because of the rarity of the phenomenon and its historical importance due the AU measure and to the discovery of Venus atmosphere. The characterization of Venus atmosphere and the measure of the solar diameter to the milliarcsecond level of precision have been studied also from satellite images. The results of the solar diameter measurements made with the observations in Athens (2004) and at the Huairou Solar Observing Station in China (2012) are presented. The topic of the oblateness of the Sun at sunset and its intrinsic value is drafted to introduce the general public to the relativistic relevance of measuring the solar figure, in the occasion of the International Year of Light 2015.

  13. Homelessness and Other Risk Factors for HIV Infection in the Current Outbreak Among Injection Drug Users in Athens, Greece.

    Science.gov (United States)

    Sypsa, Vana; Paraskevis, Dimitrios; Malliori, Meni; Nikolopoulos, Georgios K; Panopoulos, Anastasios; Kantzanou, Maria; Katsoulidou, Antigoni; Psichogiou, Mina; Fotiou, Anastasios; Pharris, Anastasia; Van De Laar, Marita; Wiessing, Lucas; Jarlais, Don Des; Friedman, Samuel R; Hatzakis, Angelos

    2015-01-01

    Objectives. We examined HIV prevalence and risk factors among injection drug users (IDUs) in Athens, Greece, during an HIV outbreak. Methods. We used respondent-driven sampling (RDS) to recruit 1404 IDUs to the Aristotle intervention in August to October 2012. We interviewed participants and tested for HIV. We performed bivariate and multivariate analyses. Results. Estimated HIV prevalence was 19.8% (RDS-weighted prevalence = 14.8%). Odds of infection were 2.3 times as high in homeless as in housed IDUs and 2.1 times as high among IDUs who injected at least once per day as among less frequent injectors (both, P homelessness as well as scaling up prevention services, such as needle and syringe distribution and other risk reduction interventions.

  14. Energy flux parametrization as an opportunity to get Urban Heat Island insights: The case of Athens, Greece (Thermopolis 2009 Campaign).

    Science.gov (United States)

    Loupa, G; Rapsomanikis, S; Trepekli, A; Kourtidis, K

    2016-01-15

    Energy flux parameterization was effected for the city of Athens, Greece, by utilizing two approaches, the Local-Scale Urban Meteorological Parameterization Scheme (LUMPS) and the Bulk Approach (BA). In situ acquired data are used to validate the algorithms of these schemes and derive coefficients applicable to the study area. Model results from these corrected algorithms are compared with literature results for coefficients applicable to other cities and their varying construction materials. Asphalt and concrete surfaces, canyons and anthropogenic heat releases were found to be the key characteristics of the city center that sustain the elevated surface and air temperatures, under hot, sunny and dry weather, during the Mediterranean summer. A relationship between storage heat flux plus anthropogenic energy flux and temperatures (surface and lower atmosphere) is presented, that results in understanding of the interplay between temperatures, anthropogenic energy releases and the city characteristics under the Urban Heat Island conditions.

  15. The thrill of victory and the agony of defeat: spontaneous expressions of medal winners of the 2004 Athens Olympic Games.

    Science.gov (United States)

    Matsumoto, David; Willingham, Bob

    2006-09-01

    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.

  16. Economic recession and emergence of an HIV-1 outbreak among drug injectors in Athens metropolitan area: a longitudinal study.

    Directory of Open Access Journals (Sweden)

    Dimitrios Paraskevis

    Full Text Available BACKGROUND: During 2011, a dramatic increase (1600% of reported HIV-1 infections among injecting drug users (IDUs was noted in Athens, Greece. We herein assess the potential causal pathways associated with this outbreak. METHODS: Our study employed high resolution HIV-1 phylogenetic and phylogeographic analyses. We examined also longitudinal data of ecological variables such as the annual growth of gross domestic product (GDP of Greece in association with HIV-1 and HCV sentinel prevalence in IDUs, unemployment and homelessness rates and HIV transmission networks in Athens IDUs before and during economic recession (2008-2012. RESULTS: IDU isolates sampled in 2011 and 2012 suggested transmission networks in 94.6% and 92.7% of the cases in striking contrast with the sporadic networking (5% during 1998-2009. The geographic origin of most HIV-1 isolates was consistent with the recently documented migratory waves in Greece. The decline in GDP was inversely correlated with annual prevalence rates of HIV and HCV and with unemployment and homelessness rates in IDUs (all p<0.001. The slope of anti-HCV prevalence in the sentinel populations of IDUs and in "new" drug injectors was found 120 and 1.9-fold (p = 0.007, p = 0.08 respectively higher in 2008-2012 (economic recession compared with 2002-2006. The median (25th, 75th size of transmission networks were 34 (12, 58 and 2 (2, 2 (p = 0.057 in 2008-2012 and 1998-2007, respectively. The coverage of harm reduction services was low throughout the study period. CONCLUSIONS: Scaling-up harm reduction services and addressing social and structural factors related to the current economic crisis should be urgently considered in environments where HIV-1 outbreaks may occur.

  17. Aims, methods and preliminary findings of the Physical Activity, Nutrition and Allergies in Children Examined in Athens (PANACEA epidemiological study

    Directory of Open Access Journals (Sweden)

    Papadimitriou Anastasios

    2007-07-01

    Full Text Available Abstract Background To determine the prevalence of asthma symptoms in a sample of Greek children aged 10–12 years, and to evaluate these rates in relation to anthropometric, lifestyle characteristics and dietary habits. Methods During 2006, 700 schoolchildren (323 male and 377 female, aged 10–12 years (4th to 6th school grade, were selected from 18 schools located in the greater Athens area. The schools were randomly selected from a list provided by the regional educational offices. To achieve a representative sample the schools enrolled were selected from various region of the Athens area. For each child a questionnaire was completed that was developed for the purposes of the study to retrieve information on: age, sex, school class, other socio-demographic characteristics, anthropometric measurements, dietary habits (through a semi-quantitative Food Frequency Questionnaire and physical activity status; the presence of asthma and allergies was assessed by the standard ISAAC questionnaire. Results The prevalence of wheezing in the past was 25% in boys and 19% in girls, while the prevalence of current wheezing was 9.0% in boys and 5.8% in girls. The prevalence of any asthma symptoms was 27.6% in boys and 20.4% in girls. Multiple logistic regression analysis revealed that increased body weight and sedentary lifestyle is associated with asthma symptoms only in boys. Conclusion The present cross-sectional study cannot establish causal relationships between asthma and increased body weight of schoolchildren; however, our findings underline the associations between asthma, increased body weight, and physical activity at population level, and urge for actions that should be taken by public health policy makers in order to prevent these conditions among children.

  18. Slant column MAX-DOAS measurements of nitrogen dioxide, formaldehyde, glyoxal and oxygen dimer in the urban environment of Athens

    Science.gov (United States)

    Gratsea, Myrto; Vrekoussis, Mihalis; Richter, Andreas; Wittrock, Folkard; Schönhardt, Anja; Burrows, John; Kazadzis, Stelios; Mihalopoulos, Nikos; Gerasopoulos, Evangelos

    2016-06-01

    Slant column (SC) densities of nitrogen dioxide (NO2), formaldehyde (HCHO), glyoxal (CHOCHO) and oxygen dimer (O4) were successfully retrieved for the first time in Athens, by using spectral measurements from a ground-based multi-azimuth Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) system. The data span the period from October 2012 to March 2014 and measurements were conducted at NOA's (National Observatory of Athens) station in Penteli (38.0°N, 23.9°E, 527 m a.s.l.) at eight azimuth angles and eight off-axis elevation angles. The SCNO2, SCHCHO and SCCHOCHO measurements at +1ο elevation angle, pointing towards the urban area, range from 0.6 to 24·1016, 0.8-9.6·1016 and 0.3-5.2·1015 molec cm-2 (mean daily values throughout the whole period), respectively. Seasonal modulation characterised by summertime maximum and wintertime minimum was observed for HCHO and CHOCHO, while for NO2 the maximum values were recorded during winter. Changes in the diurnal variability of all trace gases with season and day of the week are investigated suggesting a strong link to primary anthropogenic sources for NO2 and a weaker one, compared to photochemistry, for HCHO and CHOCHO. In addition, the impact of the reduced anthropogenic emissions during weekends on the measured SC values was quantified and 30%-50% lower SCNO2 values were found during weekends. The contribution of local urban emissions to the overall recorded amounts of the selected species was assessed. Using meteorological data from NOA's station in Penteli, the impact of the local circulation patterns on the SC levels was estimated, and a strong relation between western wind direction, which is related to the industrial area, and enhanced SC measurements was found.

  19. LMFBR type reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kawakami, Hiroto

    1995-02-07

    A reactor container of the present invention has a structure that the reactor container is entirely at the same temperature as that at the inlet of the reactor and, a hot pool is incorporated therein, and the reactor container has is entirely at the same temperature and has substantially uniform temperature follow-up property transiently. Namely, if the temperature at the inlet of the reactor core changes, the temperature of the entire reactor container changes following this change, but no great temperature gradient is caused in the axial direction and no great heat stresses due to axial temperature distribution is caused. Occurrence of thermal stresses caused by the axial temperature distribution can be suppressed to improve the reliability of the reactor container. In addition, since the laying of the reactor inlet pipelines over the inside of the reactor is eliminated, the reactor container is made compact and the heat shielding structures above the reactor and a protection structure of container walls are simplified. Further, secondary coolants are filled to the outside of the reactor container to simplify the shieldings. The combined effects described above can improve economical property and reliability. (N.H.).

  20. Light water reactor safety

    CERN Document Server

    Pershagen, B

    2013-01-01

    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

  1. Nuclear reactor physics

    CERN Document Server

    Stacey, Weston M

    2010-01-01

    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

  2. 雅典城邦早期的体育发展特征研究%Research on the Athens Early Sports Development Characteristics

    Institute of Scientific and Technical Information of China (English)

    陈补林

    2015-01-01

    Athens was a typical representative of the ancient Greek civilization. Freedom, equality, democracy and legal system are the main features of Athenian culture. In politics, economy, culture, education, sports and other areas of development, Athens is the key factor to Athens ancient Greek civilization. By means of literature, the early development of Athenian sports is summarized. The study finds that the "perfect" culture is the ultimate appeal of Athens sports; relying on the family, school, sports, fitness venues and festivals of Athens, to integrate sports in the daily life of the citizens;children play games, young people in school physical exercise, bodybuilding and adult games, sports fashion, aesthetic and physical responsibility; teachers in teaching demonstration, focusing on the practice of supervision, making good use of teaching, and encourage the all-round development of teenagers; the biggest defect in Athens sports lies in the focus on the individual and lack of team cooperation.%雅典是古希腊城邦文明的典型代表,自由、民主、平等与法制是雅典文化的主要特征。雅典在政治、经济、文化、教育、体育等领域的发展是促使古希腊城邦文明崛起的关键因素。文章借助文献资料法,对雅典城邦体育的早期发展进行总结与归纳。研究发现:“完人”培养是雅典体育的最终诉求;依托家庭、学校、运动会、健身场馆以及节日庆典,雅典将体育融入公民的日常生活;儿童玩游戏,青少年在学校锻炼身体,成人坚持健身并参与比赛,体育成为时尚、审美和责任;体育教师以示范教学为主,注重对练习者的督导,善于利用分层教学,并鼓励青少年的全面发展;雅典体育的最大缺陷在于,过分突出个人,缺乏团队合作。

  3. Spinning fluids reactor

    Science.gov (United States)

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

    2012-11-20

    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.

  4. Reactor Vessel Surveillance Program for Advanced Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Kyeong-Hoon; Kim, Tae-Wan; Lee, Gyu-Mahn; Kim, Jong-Wook; Park, Keun-Bae; Kim, Keung-Koo

    2008-10-15

    This report provides the design requirements of an integral type reactor vessel surveillance program for an integral type reactor in accordance with the requirements of Korean MEST (Ministry of Education, Science and Technology Development) Notice 2008-18. This report covers the requirements for the design of surveillance capsule assemblies including their test specimens, test block materials, handling tools, and monitors of the surveillance capsule neutron fluence and temperature. In addition, this report provides design requirements for the program for irradiation surveillance of reactor vessel materials, a layout of specimens and monitors in the surveillance capsule, procedures of installation and retrieval of the surveillance capsule assemblies, and the layout of the surveillance capsule assemblies in the reactor.

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

    Science.gov (United States)

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

    2016-04-01

    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

  6. 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

    2004-08-06

    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

  7. SNTP program reactor design

    Science.gov (United States)

    Walton, Lewis A.; Sapyta, Joseph J.

    1993-06-01

    The Space Nuclear Thermal Propulsion (SNTP) program is evaluating the feasibility of a particle bed reactor for a high-performance nuclear thermal rocket engine. Reactors operating between 500 MW and 2,000 MW will produce engine thrusts ranging from 20,000 pounds to 80,000 pounds. The optimum reactor arrangement depends on the power level desired and the intended application. The key components of the reactor have been developed and are being tested. Flow-to-power matching considerations dominate the thermal-hydraulic design of the reactor. Optimal propellant management during decay heat cooling requires a three-pronged approach. Adequate computational methods exist to perform the neutronics analysis of the reactor core. These methods have been benchmarked to critical experiment data.

  8. Fast Spectrum Reactors

    CERN Document Server

    Todd, Donald; Tsvetkov, Pavel

    2012-01-01

    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...

  9. Hybrid reactors. [Fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Moir, R.W.

    1980-09-09

    The rationale for hybrid fusion-fission reactors is the production of fissile fuel for fission reactors. A new class of reactor, the fission-suppressed hybrid promises unusually good safety features as well as the ability to support 25 light-water reactors of the same nuclear power rating, or even more high-conversion-ratio reactors such as the heavy-water type. One 4000-MW nuclear hybrid can produce 7200 kg of /sup 233/U per year. To obtain good economics, injector efficiency times plasma gain (eta/sub i/Q) should be greater than 2, the wall load should be greater than 1 MW.m/sup -2/, and the hybrid should cost less than 6 times the cost of a light-water reactor. Introduction rates for the fission-suppressed hybrid are usually rapid.

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

    Science.gov (United States)

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

    2017-03-14

    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.

  11. 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.

    Science.gov (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

    2017-03-21

    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.

  12. Multi purpose research reactor

    Energy Technology Data Exchange (ETDEWEB)

    Raina, V.K. [Research Reactor Design and Projects Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)]. E-mail: vkrain@magnum.barc.ernet.in; Sasidharan, K. [Research Reactor Design and Projects Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Sengupta, Samiran [Research Reactor Design and Projects Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Singh, Tej [Research Reactor Services Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2006-04-15

    At present Dhruva and Cirus reactors provide the majority of research reactor based facilities to cater to the various needs of a vast pool of researchers in the field of material sciences, physics, chemistry, bio sciences, research and development work for nuclear power plants and production of radio isotopes. With a view to further consolidate and expand the scope of research and development in nuclear and allied sciences, a new 20 MWt multi purpose research reactor is being designed. This paper describes some of the design features and safety aspects of this reactor.

  13. INVAP's Research Reactor Designs

    Directory of Open Access Journals (Sweden)

    Eduardo Villarino

    2011-01-01

    Full Text Available INVAP, an Argentine company founded more than three decades ago, is today recognized as one of the leaders within the research reactor industry. INVAP has participated in several projects covering a wide range of facilities, designed in accordance with the requirements of our different clients. For complying with these requirements, INVAP developed special skills and capabilities to deal with different fuel assemblies, different core cooling systems, and different reactor layouts. This paper summarizes the general features and utilization of several INVAP research reactor designs, from subcritical and critical assemblies to high-power reactors.

  14. LMFBR type reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kanbe, Mitsuru

    1997-04-04

    An LMFBR type reactor comprises a plurality of reactor cores in a reactor container. Namely, a plurality of pot containing vessels are disposed in the reactor vessel and a plurality of reactor cores are formed in a state where an integrated-type fuel assembly is each inserted to a pot, and a coolant pipeline is connected to each of the pot containing-vessel to cool the reactor core respectively. When fuels are exchanged, the integrated-type fuel assembly is taken out together with the pot from the reactor vessel in a state where the integrated-type fuel assembly is immersed in the coolants in the pot as it is. Accordingly, coolants are supplied to each of the pot containing-vessel connected with the coolant pipeline and circulate while cooling the integrated-type fuel assembly for every pot. Then, when the fuels are exchanged, the integrated type fuel assembly is taken out to the outside of the reactor together with the pot by taking up the pot from the pot-containing vessel. Then, neutron economy is improved to thereby improve reactor power and the breeding ratio. (N.H.)

  15. Circulation of a multiresistant, conjugative, IncA/C plasmid within the nosocomial Providencia stuartii population in the Athens area.

    Science.gov (United States)

    Giakkoupi, Panagiota; Tryfinopoulou, Kyriaki; Polemis, Michalis; Pappa, Olga; Miriagou, Vivi; Vatopoulos, Alkiviadis

    2015-05-01

    The objective of the study is to report a multidrug-resistant outbreak of Providencia stuartii that occurred in inpatients in the Athens area in 2012 resulting from a very successful transmissible A/C multidrug-resistant plasmid. Thirteen multidrug-resistant P. stuartii clinical isolates from 5 hospitals were studied. Molecular typing was performed by pulsed-field gel electrophoresis. Antibiotic resistance genes and their genetic surround were detected by PCR and sequencing. Plasmid analysis included conjugation experiments using liquid cultures, sizing by S1 digestion, and incompatibility replicon typing by PCR. Isolates were grouped into 2 distinct clonal types A and B, exhibiting similarity less than 70%. Isolates of type A were recovered from patients hospitalized in 4 different hospitals with no obvious epidemiological linkage, while isolates of type B were recovered from patients treated in a single hospital. Both clonal types harbored a conjugative plasmid of 130 bp and IncA/C replicon type carrying 5 β-lactamase genes bla(SHV-5), bla(VEB-1), bla(VIM-1), bla(OXA-10), and bla(TEM-1) and aminoglycosides resistant determinants. All β-lactamase genes were included in stable structures as IS26, IS1999, and In-e541. The current plasmid seemed to have many common determinants with previously reported plasmids derived from P. stuartii and Proteus mirabilis clinical isolates and exhibited the ability to circulate in nosocomial bacterial populations.

  16. Impacts of the solar eclipse of 29 March 2006 on the surface ozone and nitrogen dioxide concentrations at Athens, Greece

    Directory of Open Access Journals (Sweden)

    C. Tzanis

    2007-10-01

    Full Text Available The behavior of surface ozone and nitrogen dioxide concentration as well as the variations in various meteorological parameters before, during and after the total solar eclipse of 29 March 2006 has been examined. This analysis is based on measurements performed at four stations located in the greater Athens basin in Greece. The experimental data demonstrated that the solar eclipse phenomenon affects the surface ozone and nitrogen dioxide concentrations as well as the temperature, the relative humidity and the wind speed near the ground. The reduction of the solar ultraviolet radiation at 312 and 365 nm reached 97% and 93% respectively, while the air temperature dropped, the relative humidity increased and the wind speed decreased. The percentage change (decrease of surface ozone concentration was maximized one hour after the maximum phase of the eclipse due to the decreased efficiency of the photochemical ozone formation. The surface nitrogen dioxide concentration increased and the time lag of the nitrogen dioxide response to the solar eclipse was found to be different for each station. A plausible cause for the increase in NO2 concentration may be the conversion of NO to NO2 through reaction with pre-existing O3 along with the low photolysis rates of NO2 as a consequence of the decreased solar radiation during the solar eclipse event.In general, the time response to the eclipse phenomenon was different for each of the aforementioned parameters.

  17. Inter-comparison of lidar and ceilometer retrievals for aerosol and Planetary Boundary Layer profiling over Athens, Greece

    Directory of Open Access Journals (Sweden)

    G. Tsaknakis

    2011-06-01

    Full Text Available This study presents an inter-comparison of two active remote sensors (lidar and ceilometer to determine the mixing layer height and structure of the Planetary Boundary Layer (PBL and to retrieve tropospheric aerosol vertical profiles over Athens, Greece. This inter-comparison was performed under various strongly different aerosol loads/types (urban air pollution, biomass burning and Saharan dust event, implementing two different lidar systems (one portable Raymetrics S.A. lidar system running at 355 nm and one multi-wavelength Raman lidar system running at 355 nm, 532 nm and 1064 nm and one CL31 Vaisala S.A. ceilometer (running at 910 nm. Spectral conversions of the ceilometer's data were performed using the Ångström exponent estimated by ultraviolet multi-filter radiometer (UV-MFR measurements. The inter-comparison was based on two parameters: the mixing layer height determined by the presence of the suspended aerosols and the attenuated backscatter coefficient. Additionally, radiosonde data were used to derive the PBL height. In general, a good agreement was found between the ceilometer and the lidar techniques in both inter-compared parameters in the height range from 500 m to 5000 m, while the limitations of each instrument are also examined.

  18. 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.

    2011-12-01

    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.

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

    Science.gov (United States)

    Macias-Duarte, Alberto; Conway, Courtney J.

    2015-01-01

    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.

  20. 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

    2011-02-01

    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.

  1. The relationship between acculturation factors and symptoms of depression: a cross-sectional study with immigrants living in Athens.

    Science.gov (United States)

    Gonidakis, Fragiskos; Korakakis, Panagiotis; Ploumpidis, Dimitris; Karapavlou, Dafni-Alexandra; Rogakou, Efi; Madianos, Michael G

    2011-09-01

    The process of acculturation observed in immigrants is part of an adjustment to the values and norms of a new society, and possibly the loss of norms of the society of origin. Acculturation has been linked to stress-related psychological disorders such as depression. The present study investigates the relationship between three acculturation domains (everyday life behaviors, wishful orientation/nostos, and ethnic identity) and symptoms of depression in a sample of foreign immigrants living in Athens, Greece. The sample consisted of 317 immigrants who visited two non-governmental organization polyclinics. All participants were interviewed using the Immigrant Acculturation Scale (IAS) and the Center for Epidemiological Studies Depression Scale (CES-D). The results showed that 133 (42%) out of the 317 interviewees were in a depressive state (CES-D > 15). The main finding was that high CES-D scores were related to low scores in the IAS Everyday Life and Wishful Orientation factors, while no relationship was found between depressive symptomatology and the IAS Identity factor. Short duration of stay in Greece, lack of steady job, and lack of residence permit were also related to high CES-D scores. In conclusion, adaptation to mainstream culture daily behaviors as well as the wish to integrate with individuals from the mainstream culture and settle permanently in the new country could be seen as part of an adaptive mechanism that protects the individual from experiencing depressive symptomatology.

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

    Directory of Open Access Journals (Sweden)

    Marios Panagiotou

    2014-01-01

    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.

  3. On the influence of the urban heat island on the cooling load of a school building in Athens, Greece

    Science.gov (United States)

    Bagiorgas, H. S.; Mihalakakou, G.

    2016-02-01

    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.

  4. Light water reactor program

    Energy Technology Data Exchange (ETDEWEB)

    Franks, S.M.

    1994-12-31

    The US Department of Energy`s Light Water Reactor Program is outlined. The scope of the program consists of: design certification of evolutionary plants; design, development, and design certification of simplified passive plants; first-of-a-kind engineering to achieve commercial standardization; plant lifetime improvement; and advanced reactor severe accident program. These program activities of the Office of Nuclear Energy are discussed.

  5. Space Nuclear Reactor Engineering

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-03-06

    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.

  6. Reactor Materials Research

    Energy Technology Data Exchange (ETDEWEB)

    Van Walle, E

    2001-04-01

    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)

  7. Nuclear reactor design

    CERN Document Server

    2014-01-01

    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.

  8. Status of French reactors

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-08-01

    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.

  9. Slurry reactor design studies

    Energy Technology Data Exchange (ETDEWEB)

    Fox, J.M.; Degen, B.D.; Cady, G.; Deslate, F.D.; Summers, R.L. (Bechtel Group, Inc., San Francisco, CA (USA)); Akgerman, A. (Texas A and M Univ., College Station, TX (USA)); Smith, J.M. (California Univ., Davis, CA (USA))

    1990-06-01

    The objective of these studies was to perform a realistic evaluation of the relative costs of tublar-fixed-bed and slurry reactors for methanol, mixed alcohols and Fischer-Tropsch syntheses under conditions where they would realistically be expected to operate. The slurry Fischer-Tropsch reactor was, therefore, operated at low H{sub 2}/CO ratio on gas directly from a Shell gasifier. The fixed-bed reactor was operated on 2.0 H{sub 2}/CO ratio gas after adjustment by shift and CO{sub 2} removal. Every attempt was made to give each reactor the benefit of its optimum design condition and correlations were developed to extend the models beyond the range of the experimental pilot plant data. For the methanol design, comparisons were made for a recycle plant with high methanol yield, this being the standard design condition. It is recognized that this is not necessarily the optimum application for the slurry reactor, which is being proposed for a once-through operation, coproducing methanol and power. Consideration is also given to the applicability of the slurry reactor to mixed alcohols, based on conditions provided by Lurgi for an Octamix{trademark} plant using their standard tubular-fixed reactor technology. 7 figs., 26 tabs.

  10. Gas cooled fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1972-06-01

    Although most of the development work on fast breeder reactors has been devoted to the use of liquid metal cooling, interest has been expressed for a number of years in alternative breeder concepts using other coolants. One of a number of concepts in which interest has been retained is the Gas-Cooled Fast Reactor (GCFR). As presently envisioned, it would operate on the uranium-plutonium mixed oxide fuel cycle, similar to that used in the Liquid Metal Fast Breeder Reactor (LMFBR), and would use helium gas as the coolant.

  11. Microfluidic electrochemical reactors

    Science.gov (United States)

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

    2011-03-22

    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.

  12. 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.

    1980-07-01

    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.

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

    Science.gov (United States)

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

    2015-06-01

    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.

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

    Science.gov (United States)

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

    2016-05-01

    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.

  15. Factor structure of the Athens Insomnia Scale and its associations with demographic characteristics and depression in adolescents.

    Science.gov (United States)

    Yen, Cheng-Fang; King, Bryan H; Chang, Yu-Ping

    2010-03-01

    The eight-item Athens Insomnia Scale (AIS-8) is an instrument that has been used frequently to assess insomnia problems. Previous research on adults has found that the AIS-8 functioned as a sole component. This study aimed to examine the prevalence rates of insomnia problems on the AIS-8, the factor structure of the AIS-8 in adolescents and its associations with demographic characteristics and depression in adolescents. A total of 8319 adolescent students (4334 girls and 3985 boys, mean age = 14.7 years, standard deviation = 1.7 years) in southern Taiwan were recruited into this study and completed the AIS-8. We performed an exploratory factor analysis to examine the factor structure of the AIS-8, and used the parallel analysis for making decisions regarding factor retention. We also used multiple regression analysis models to determine the associations between insomnia and demographic characteristics and depression. The results found that a high proportion of adolescents had insomnia problems as measured by the AIS-8. The AIS-8 was composed of two different factors when used among a large adolescent population, including insomnia symptoms (factor 1) and subjective sleep and daytime distress (factor 2). While being male, being younger, and having depression were associated positively with the severity of insomnia symptoms (factor 1), being older, living in urban areas, and having depression were associated positively with the severity of subjective sleep and daytime distress (factor 2). Clinicians and researchers should consider the different meanings of the two factors of the AIS-8 when using this tool to assess insomnia problems in adolescents.

  16. Chemical and spectroscopic investigation of the Raphael's cartoon of the School of Athens from the Pinacoteca Ambrosiana

    Science.gov (United States)

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

    2016-12-01

    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.

  17. 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.

    2011-12-01

    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.

  18. Development of a road transport emission inventory for Greece and the Greater Athens Area: effects of important parameters.

    Science.gov (United States)

    Fameli, K M; Assimakopoulos, V D

    2015-02-01

    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.

  19. Road traffic emissions impact on air quality of the Greater Athens Area based on a 20 year emissions inventory.

    Science.gov (United States)

    Progiou, Athena G; Ziomas, Ioannis C

    2011-12-01

    During the last decades, the Greater Athens Area (GAA), among many other urban agglomerations, faces atmospheric pollution problems mainly associated with high levels of particulates, nitrogen dioxide and ozone. The major pollution source for the GAA is road transportation. In this sense, the aim of this work was to investigate the existence of a direct relationship linking air pollutant concentration levels and road traffic emissions. To this aim, air pollutant emissions from road traffic were calculated for the period 1990-2009 and then the relationship with the corresponding air pollutant concentrations was investigated. The calculated results have revealed that all pollutants examined show a strong decreasing trend whereas the age of the vehicles and the corresponding engine technology determine the amount of the pollutants emitted. In addition, the NO(2)/NO(x) emission ratio presents a constant increase in the course of the years, according to the respective NO(2)/NO(x) concentration ratio. Furthermore, the comparison between emission calculations and the corresponding measured concentrations shows a highly significant correlation providing therefore evidence to policy makers that all pollution abatement measures can be defined and assessed with regard to their anticipated effect on air pollutant emissions. Detailed analysis of the 2009 emissions shows that, in general, passenger cars are the major polluters for CO, NMVOCs and CH(4), whereas PM(10) and NO(x) are mostly associated with heavy duty vehicles (HDVs). Finally, it appears that vehicles aged more than 15 years are responsible for the major part of the air pollutants emitted.

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

    Science.gov (United States)

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

    2012-01-01

    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.

  1. Reactor BR2. Introduction

    Energy Technology Data Exchange (ETDEWEB)

    Gubel, P

    2001-04-01

    The BR2 is a materials testing reactor and is still one of SCK-CEN's important nuclear facilities. After an extensive refurbishment to compensate for the ageing of the installation, the reactor was restarted in April 1997. During the last three years, the availability of the installation was maintained at an average level of 97.6 percent. In the year 2000, the reactor was operated for a total of 104 days at a mean power of 56 MW. In 2000, most irradiation experiments were performed in the CALLISTO PWR loop. The report describes irradiations achieved or under preparation in 2000, including the development of advanced facilities and concept studies for new programmes. An overview of the scientific irradiation programmes as well as of the R and D programme of the BR2 reactor in 2000 is given.

  2. Reactor Neutrino Spectra

    CERN Document Server

    Hayes, A C

    2016-01-01

    We present a review of the antineutrino spectra emitted from reactors. Knowledge of these and their associated uncertainties are crucial for neutrino oscillation studies. The spectra used to-date have been determined by either conversion of measured electron spectra to antineutrino spectra or by summing over all of the thousands of transitions that makeup the spectra using modern databases as input. The uncertainties in the subdominant corrections to beta-decay plague both methods, and we provide estimates of these uncertainties. Improving on current knowledge of the antineutrino spectra from reactors will require new experiments. Such experiments would also address the so-called reactor neutrino anomaly and the possible origin of the shoulder observed in the antineutrino spectra measured in recent high-statistics reactor neutrino experiments.

  3. New reactor type proposed

    CERN Multimedia

    2003-01-01

    "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).

  4. 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

    Science.gov (United States)

    Fameli, Kyriaki-Maria; Assimakopoulos, Vasiliki D.

    2016-07-01

    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.

  5. Helias reactor studies

    Energy Technology Data Exchange (ETDEWEB)

    Beidler, C.D. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Grieger, G. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Harmeyer, E. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Kisslinger, J. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Karulin, N. [Nuclear Fusion Institute, Moscow (Russian Federation); Maurer, W. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany); Nuehrenberg, J. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Rau, F. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Sapper, J. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Wobig, H. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany)

    1995-10-01

    The present status of Helias reactor studies is characterised by the identification and investigation of specific issues which result from the particular properties of this type of stellarator. On the technical side these are issues related to the coil system, while physics studies have concentrated on confinement, alpha-particle behaviour and ignition conditions. The usual assumptions have been made in those fields which are common to all toroidal fusion reactors: blanket and shield, refuelling and exhaust, safety and economic aspects. For blanket and shield sufficient space has been provided, a detailed concept will be developed in future. To date more emphasis has been placed on scoping and parameter studies as opposed to fixing a specific set of parameters and providing a detailed point study. One result of the Helias reactor studies is that physical dimensions are on the same order as those of tokamak reactors. However, it should be noticed that this comparison is difficult in view of the large spectrum of tokamak reactors ranging from a small reactor like Aries, to a large device such as SEAFP. The notion that the large aspect ratio of 10 or more in Helias configurations also leads to large reactors is misleading, since the large major radius of 22 m is compensated by the average plasma radius of 1.8 m and the average coil radius of 5 m. The plasma volume of 1400 m{sup 3} is about the same as the ITER reactor and the magnetic energy of the coil system is about the same or even slightly smaller than envisaged in ITER. (orig.)

  6. Future Reactor Experiments

    OpenAIRE

    He, Miao

    2013-01-01

    The measurement of the neutrino mixing angle $\\theta_{13}$ opens a gateway for the next generation experiments to measure the neutrino mass hierarchy and the leptonic CP-violating phase. Future reactor experiments will focus on mass hierarchy determination and the precision measurement of mixing parameters. Mass hierarchy can be determined from the disappearance of reactor electron antineutrinos based on the interference effect of two separated oscillation modes. Relative and absolute measure...

  7. Reactor Neutrino Experiments

    OpenAIRE

    Cao, Jun

    2007-01-01

    Precisely measuring $\\theta_{13}$ is one of the highest priority in neutrino oscillation study. Reactor experiments can cleanly determine $\\theta_{13}$. Past reactor neutrino experiments are reviewed and status of next precision $\\theta_{13}$ experiments are presented. Daya Bay is designed to measure $\\sin^22\\theta_{13}$ to better than 0.01 and Double Chooz and RENO are designed to measure it to 0.02-0.03. All are heading to full operation in 2010. Recent improvements in neutrino moment measu...

  8. 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....

  9. Moon base reactor system

    Science.gov (United States)

    Chavez, H.; Flores, J.; Nguyen, M.; Carsen, K.

    1989-01-01

    The objective of our reactor design is to supply a lunar-based research facility with 20 MW(e). The fundamental layout of this lunar-based system includes the reactor, power conversion devices, and a radiator. The additional aim of this reactor is a longevity of 12 to 15 years. The reactor is a liquid metal fast breeder that has a breeding ratio very close to 1.0. The geometry of the core is cylindrical. The metallic fuel rods are of beryllium oxide enriched with varying degrees of uranium, with a beryllium core reflector. The liquid metal coolant chosen was natural lithium. After the liquid metal coolant leaves the reactor, it goes directly into the power conversion devices. The power conversion devices are Stirling engines. The heated coolant acts as a hot reservoir to the device. It then enters the radiator to be cooled and reenters the Stirling engine acting as a cold reservoir. The engines' operating fluid is helium, a highly conductive gas. These Stirling engines are hermetically sealed. Although natural lithium produces a lower breeding ratio, it does have a larger temperature range than sodium. It is also corrosive to steel. This is why the container material must be carefully chosen. One option is to use an expensive alloy of cerbium and zirconium. The radiator must be made of a highly conductive material whose melting point temperature is not exceeded in the reactor and whose structural strength can withstand meteor showers.

  10. Conference report on the 28th annual meeting of the European Musculo-Skeletal Oncology Society, 29 April-1 May 2015, Athens.

    Science.gov (United States)

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

    2015-01-01

    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.

  11. Changes in Nitrogen to Phosphorus ratio in the Inner Saronikos Gulf (West Aegean Sea) in relation to the operation of the Sewage Treatment Plant of Athens, Greece

    Science.gov (United States)

    Psyllidou-Giouranovits, Rosa

    2013-04-01

    In this work we provide an overview of nitrogen (N) to phosphorus (P) ratio in the inner Saronikos gulf as it has changed over the last twenty five (25) years in relation to the sewage discharges from the Sewage Treatment Plant of Athens in Psittalia Island. Saronikos gulf receives effluents from Athens Metropolitan area (population over 5 million). Until 1994, domestic and industrial sewage of Athens was discharged untreated into the surface water layer of Keratsini and Elefsis bay, whereas, after 1994, the sewage of the Athens Metropolitan area were primarily treated in Psitallia Sewage Treatment Plant and discharged in the inner Saronikos Gulf. Additionally, the secondary stage of the Psittalia Sewage Plant operated in the end of 2004 affecting the nitrogen to phosphorus (DIN:P) ratio (DIN stands for nitrate+nitrite+ammonium). The treated effluent plume frorm Psittalia Sewage Treatment Plant is trapped within the seasonal pycnocline developed during May-November, whereas, during the mixing period (December-April) it reaches the sea-surface. During the last 25 years, significant temporal variation of nutrient concentrations has been observed which has revealed an increase of the DIN:P ratio near the Psittalia Sewage Treatment Plant. In the vicinity of the sewage outfall in Psittalia, DIN:P ratio in the deep layer (30m-bottom) did not show significant variation between the two periods: before and after the operation of the Sewage Treatment Plant (12.9 before the operation of the sewage treatment and 13.3 after the operation of the sewage treatment) showing that inorganic nitrogen and phosphate changed almost with the same rate. However, the limiting factor for phytoplankton growth remains nitrogen. On the contrary, significant increase of DIN:P ratio was observed in the surface layer between the two periods, during summer (stratified period). DIN:P increased from 5.9 for the period 1987-1995 (before the Sewage Treatment Plant operation) to 19.6 for the period 1995

  12. 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.

    1998-01-01

    the ozone levels reach values up to 66% greater than values outside the basin. There is also an increase in ozone and PAN mixing ratios from the south to the north and from lower to higher locations, within the GAA. On-line PAN-measurements with a time resolution of 5 min at three sites located almost along...... 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....

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

    Energy Technology Data Exchange (ETDEWEB)

    P. Delmolino

    2005-05-06

    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.

  14. REACTOR GROUT THERMAL PROPERTIES

    Energy Technology Data Exchange (ETDEWEB)

    Steimke, J.; Qureshi, Z.; Restivo, M.; Guerrero, H.

    2011-01-28

    Savannah River Site has five dormant nuclear production reactors. Long term disposition will require filling some reactor buildings with grout up to ground level. Portland cement based grout will be used to fill the buildings with the exception of some reactor tanks. Some reactor tanks contain significant quantities of aluminum which could react with Portland cement based grout to form hydrogen. Hydrogen production is a safety concern and gas generation could also compromise the structural integrity of the grout pour. Therefore, it was necessary to develop a non-Portland cement grout to fill reactors that contain significant quantities of aluminum. Grouts generate heat when they set, so the potential exists for large temperature increases in a large pour, which could compromise the integrity of the pour. The primary purpose of the testing reported here was to measure heat of hydration, specific heat, thermal conductivity and density of various reactor grouts under consideration so that these properties could be used to model transient heat transfer for different pouring strategies. A secondary purpose was to make qualitative judgments of grout pourability and hardened strength. Some reactor grout formulations were unacceptable because they generated too much heat, or started setting too fast, or required too long to harden or were too weak. The formulation called 102H had the best combination of characteristics. It is a Calcium Alumino-Sulfate grout that contains Ciment Fondu (calcium aluminate cement), Plaster of Paris (calcium sulfate hemihydrate), sand, Class F fly ash, boric acid and small quantities of additives. This composition afforded about ten hours of working time. Heat release began at 12 hours and was complete by 24 hours. The adiabatic temperature rise was 54 C which was within specification. The final product was hard and displayed no visible segregation. The density and maximum particle size were within specification.

  15. Scaleable, High Efficiency Microchannel Sabatier Reactor Project

    Data.gov (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...

  16. Origins of n-alkanes, carbonyl compounds and molecular biomarkers in atmospheric fine and coarse particles of Athens, Greece.

    Science.gov (United States)

    Andreou, G; Rapsomanikis, S

    2009-10-15

    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

  17. CO Pollution: a comparative study during high traffic conditions in the cities of Athens, Naples and Islamabad. Health impacts

    Science.gov (United States)

    Polichetti, Juliano; Grigoropoulos, Konstantinos; Ferentinos, George; Tselentis, Vasilios; Nastos, Panagiotis; Xatzioakeimidis, Konstantinos; Dimas, Konstantinos; Khan, Ubaidullah

    2010-05-01

    Since the 19th century anthropogenic activities in urban areas have increased dramatically due to socio-economic evolution, increased urbanization and transport needs. Fifty seven years ago London experienced the impacts of an acute atmospheric pollution episode, due to elevated levels of black carbon aerosols (BC) and SO2, leading to the realization that uncontrolled emissions to the atmosphere lead to severe impacts on human health. Many large cities (Mega cities) in the developed and developing world have, for the last two decades, been plagued by high levels of atmospheric pollution, a problem that the European and worldwide scientific community are at present studying with measurable success. However, due to rapid industrial development and the ever increasing traffic, many more studies are required to support decision makers and governments on measures to reduce atmospheric pollution and mitigate the associated serious health effects on the population. Registered health problems are numerous and dramatic in all ages groups, but particularly so in infants, and patients suffering from chronic diseases due to increased levels of pollutants and nocive substance inhaled, entering the lungs and blood stream and finally being deposited in several organs. Recent studies indicate that cardiac arrhythmias associated to increased atmospheric pollution pose a serious threat to human health. K.N.Grigoropoulos,et al.2008. This study is based on monitoring and mapping CO levels in six areas 3 different cities i.e. Athens, Naples and Islamabad, the objective being to present and analyze the spatial and temporal variability of carbon monoxide (CO) levels leading to the estimation of the concentration levels and the quantities inhaled by pedestrians on a daily basis. It is well know that exposure to carbon monoxide concentration values in excess of 200ppm for 2-3 h usually create headaches, tiredness, fatigue and nausea, whereas human exposure of values of 800 ppm for over

  18. LMFBR type reactor

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Takeshi; Iida, Masaaki; Moriki, Yasuyuki

    1994-10-18

    A reactor core is divided into a plurality of coolants flowrate regions, and electromagnetic pumps exclusively used for each of the flowrate regions are disposed to distribute coolants flowrates in the reactor core. Further, the flowrate of each of the electromagnetic pumps is automatically controlled depending on signals from a temperature detector disposed at the exit of the reactor core, so that the flowrate of the region can be controlled optimally depending on the burning of reactor core fuels. Then, the electromagnetic pumps disposed for every divided region are controlled respectively, so that the coolants flowrate distribution suitable to each of the regions can be attained. Margin for fuel design is decreased, fuels are used effectively, as well as an operation efficiency can be improved. Moreover, since the electromagnetic pump has less flow resistance compared with a mechanical type pump, and flow resistance of the reactor core flowrate control mechanism is eliminated, greater circulating flowrate can be ensured after occurrence of accident in a natural convection using a buoyancy of coolants utilizable for after-heat removal as a driving force. (N.H.).

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

    CERN Document Server

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

    2015-01-01

    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 at the National Observatory of Athens, procuring two fast-frame cameras, 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 m...

  20. The road traffic accident of Emmanuel Roides: A case report of cranio-maxillofacial trauma in Athens towards the end of the 19th century

    Directory of Open Access Journals (Sweden)

    Evangelia Ch. PAPADOPOULOU

    2013-08-01

    Full Text Available Introduction: The author of the famous novel “Pope Joan” Emmanuel Roides was a victim of a road traffic accident in Athens towards the end of the 19th century, resulting in a maxillary fracture.Material and method: The critical study “The tragic notebook of Emmanuel Roides”, written by K. G. Kassinis,was studied in detail, to find out how the road traffic accident was happened, the consequences of Emmanuel Roides’s injury, as well as its management.Results: On July 27, 1885 Emmanuel Roides was hit by two carriages in such a way that passing the wheel of one carriage above his head caused a maxillary fracture.Doctors engaged in the surgical management and his overall care were general surgeons as well as a dentist.Conclusions: Emmanuel Roides’s case enriches our knowledge about management of maxillofacial injuries in Athens towards the end of the 19th century, bringing forward the timeless problem of road traffic accidentsand road safety, as basic etiological factors of viscerocranium fractures.

  1. 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

    2015-12-01

    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.

  2. Chemical composition and sources of ambient aerosol in an urban environment over Athens, Greece: Case study on the role of wintertime biomass burning

    Science.gov (United States)

    Theodosi, Christina

    2016-04-01

    This study examines the chemical composition of aerosols over the Greater Athens Area (GAA). To achieve this, particulate matter sampling has been conducted on a 6h-24h basis and more than 700 aerosol samples were collected at downtown Athens, in Thissio from January 2013 to December 2015. All samples, after mass quantification, were analyzed for major anions (Cl^-, Br^-, NO{_3^-}, SO{_4-2}, PO{_4-3}, C_2O{_4-2}), cations (NH{_4^+}, K^+, Na^+, Mg+2, Ca+2), trace elements (Al, As, Ca, Cd, Co, Cr, Cu, Fe, V, Zn, Mn, Ni, Pb, P, S, Sb), organic carbon (OC) and elemental carbon (EC). Aerosol chemical mass closure calculations indicated that carbonaceous aerosol constitutes a major component, along with nitrate and sulfate anions, dust, cations and EC. Moreover, during the winter periods of December 2012-January 2013 and December 2013-January 2014, air pollution due to excessive use of biomass for domestic heating has been reported as a major environmental problem in the area. To assess the importance of biomass burning as a source of air pollution over the GAA three main sugars specific biomass burning tracers (levoglucosan, mannosan and galactosan) and Polycyclic aromatic hydrocarbons (PAHs) were also analyzed during the winter period. Acknowledgments This work was supported by the State Scholarship Foundation ("IKY Fellowships of Excellence for Postgraduate Studies in Greece - Siemens Programme") in the framework of the Hellenic Republic-Siemens Settlement Agreement.

  3. NELIOTA: ESA's new NEO lunar impact monitoring project with the 1.2m telescope at the National Observatory of Athens

    Science.gov (United States)

    Bonanos, Alceste; Liakos, Alexios; Xilouris, Manolis; Boumis, Panayotis; Bellas-Velidis, Ioannis; Marousis, Athanassios; Dapergolas, Anastasios; Fytsilis, Anastasios; Noutsopoulos, Andreas; Charmandaris, Vassilis; Tsiganis, Kleomenis; Tsinganos, Kanaris; Els, Sebastian; Koschny, Detlef; Lock, Tim; Navarro, Vicente

    2016-08-01

    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 via lunar monitoring. 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, starting in the Summer 2016, in search of NEO impact flashes on the Moon. The project involves: (i) a complete refurbishment of the 40 year old 1.2m Kryoneri telescope of the National Observatory of Athens, (ii) development of a Lunar imager for the prime focus with two fast-frame sCMOS cameras, and (iii) procurement of servers for data processing and storage. Furthermore, we have developed a software system that controls the telescope and the cameras, processes the images and automatically detects lunar flashes. NELIOTA provides a web-based user interface, where the impact events, after their verification and characterization, will be reported and made available to the scientific community and the general public. The novelty of this project is the dedication of a large, 1.2m telescope for lunar monitoring, which is expected to characterize the frequency and distribution of NEOs weighing as little as a few grams.

  4. Reactor Structural Materials: Reactor Pressure Vessel Steels

    Energy Technology Data Exchange (ETDEWEB)

    Chaouadi, R

    2000-07-01

    The objectives of SCK-CEN's R and D programme on Rector Pressure Vessel (RPV) Steels are:(1) to complete the fracture toughness data bank of various reactor pressure vessel steels by using precracked Charpy specimens that were tested statically as well as dynamically; (2) to implement the enhanced surveillance approach in a user-friendly software; (3) to improve the existing reconstitution technology by reducing the input energy (short cycle welding) and modifying the stud geometry. Progress and achievements in 1999 are reported.

  5. Comparison of Placido disc and Scheimpflug image-derived topography-guided excimer laser surface normalization combined with higher fluence CXL: the Athens Protocol, in progressive keratoconus

    Directory of Open Access Journals (Sweden)

    Kanellopoulos AJ

    2013-07-01

    Full Text Available Anastasios John Kanellopoulos,1,2 George Asimellis11Laservision.gr Eye Institute, Athens, Greece; 2New York University School of Medicine, Department of Opthalmology, NY, NY, USABackground: The purpose of this study was to compare the safety and efficacy of two alternative corneal topography data sources used in topography-guided excimer laser normalization, combined with corneal collagen cross-linking in the management of keratoconus using the Athens protocol, ie, a Placido disc imaging device and a Scheimpflug imaging device.Methods: A total of 181 consecutive patients with keratoconus who underwent the Athens protocol between 2008 and 2011 were studied preoperatively and at months 1, 3, 6, and 12 postoperatively for visual acuity, keratometry, and anterior surface corneal irregularity indices. Two groups were formed, depending on the primary source used for topoguided photoablation, ie, group A (Placido disc and group B (Scheimpflug rotating camera. One-year changes in visual acuity, keratometry, and seven anterior surface corneal irregularity indices were studied in each group.Results: Changes in visual acuity, expressed as the difference between postoperative and preoperative corrected distance visual acuity were +0.12 ± 0.20 (range +0.60 to -0.45 for group A and +0.19 ± 0.20 (range +0.75 to -0.30 for group B. In group A, K1 (flat keratometry changed from 45.202 ± 3.782 D to 43.022 ± 3.819 D, indicating a flattening of -2.18 D, and K2 (steep keratometry changed from 48.670 ± 4.066 D to 45.865 ± 4.794 D, indicating a flattening of -2.805 D. In group B, K1 (flat keratometry changed from 46.213 ± 4.082 D to 43.190 ± 4.398 D, indicating a flattening of -3.023 D, and K2 (steep keratometry changed from 50.774 ± 5.210 D to 46.380 ± 5.006 D, indicating a flattening of -4.394 D. For group A, the index of surface variance decreased to -5.07% and the index of height decentration to -26.81%. In group B, the index of surface variance

  6. Thermionic Reactor Design Studies

    Energy Technology Data Exchange (ETDEWEB)

    Schock, Alfred

    1994-08-01

    Paper presented at the 29th IECEC in Monterey, CA in August 1994. The present paper describes some of the author's conceptual designs and their rationale, and the special analytical techniques developed to analyze their (thermionic reactor) performance. The basic designs, first published in 1963, are based on single-cell converters, either double-ended diodes extending over the full height of the reactor core or single-ended diodes extending over half the core height. In that respect they are similar to the thermionic fuel elements employed in the Topaz-2 reactor subsequently developed in the Soviet Union, copies of which were recently imported by the U.S. As in the Topaz-2 case, electrically heated steady-state performance tests of the converters are possible before fueling.

  7. Nuclear Rocket Engine Reactor

    CERN Document Server

    Lanin, Anatoly

    2013-01-01

    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.

  8. Operation of Reactor

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    3.1 Annual Report of SPR Operation Chu Shaochu Having overseen by National Nuclear Safety Administration and specialists, the reactor restarted up successfully after Safety renovation on April 16, 1996. In August 1996 the normal operation of SPR was approved by the authorities of Naitonal Nuclear Safety Administration. 1 Operation status In 1996, the reactor operated safely for 40 d and the energy released was about 137.3 MW·d. The operation status of SPR is shown in table 1. The reactor started up to higher power (power more than 1 MW) and lower power (for physics experiments) 4 times and 14 times respectively. Measurement of control rod efficiency and other measurement tasks were 2 times and 5 times respectively.

  9. An Overview of Reactor Concepts, a Survey of Reactor Designs.

    Science.gov (United States)

    1985-02-01

    Public Affairs Office and is releasaole to the National Technical Information Services (NTIS). At NTIS, it will be available to the general public...Reactors that use deu- terium (heavy water) as a coolant can use natural uranium as a fuel. The * Canadian reactor, CANDU , utilizes this concept...reactor core at the top and discharged at the Dotton while the reactor is in operation. The discharged fuel can then b inspected to see if it can De used

  10. Oscillatory flow chemical reactors

    Directory of Open Access Journals (Sweden)

    Slavnić Danijela S.

    2014-01-01

    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.

  11. 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

    2007-06-01

    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

  12. 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)

    1994-03-01

    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.

  13. Reactor Materials Research

    Energy Technology Data Exchange (ETDEWEB)

    Van Walle, E

    2002-04-01

    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.

  14. Reactor operation environmental information document

    Energy Technology Data Exchange (ETDEWEB)

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

    1989-12-01

    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.

  15. High Flux Isotope Reactor (HFIR)

    Data.gov (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...

  16. Reactor operation safety information document

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    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)

  17. FLOODPLAIN, ATHENS COUNTY, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — The Floodplain Mapping/Redelineation study deliverables depict and quantify the flood risks for the study area. The primary risk classifications used are the...

  18. Grande Bretagne Hotel Athens

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Grande Bretagne酒店在过去的130年间被认为是雅典的“贵族包厢”。它坐落于市中心最著名的街区之一.对面是宪法广场,国会议院和国家花园,酒店的地理位置非常理想.通过短时间的步行就可以到达附近的高级购物区,餐馆,露天咖啡馆,博物馆和商务区,到目前为止,这家酒店已经接待了很多的国际领导人和知名人士。

  19. 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

    2017-03-01

    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

  20. Architectures, Concepts and Technologies for Service Oriented Computing : proceedings of ACT4SOC 2010, 4th International Workshop on Architectures, Concepts and Technologies for Service Oriented Computing in cnjunction with ICSOFT 2010, Athens, Greece, July 2010

    NARCIS (Netherlands)

    Sinderen, van Marten; Sapkota, Brahmananda

    2010-01-01

    This volume contains the proceedings of the Fourth International Workshop on Architectures, Concepts and Technologies for Service Oriented Computing (ACT4SOC 2010), held on July 23 in Athens, Greece, in conjunction with the Fourth International Conference on Software and Data Technologies (ICSOFT 20

  1. Thermal Reactor Safety

    Energy Technology Data Exchange (ETDEWEB)

    1980-06-01

    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.

  2. Chromatographic and Related Reactors.

    Science.gov (United States)

    1988-01-07

    special information about effects of surface heteroge- neity in the methanation reaction. Studies of an efficient multicolumn assembly for measuring...of organic basic catalysts such as pyridine and 4-methylpicoline. It was demonstrated that the chromatographic reactor gave special information about...Programmed Reaction to obtain special information about surface heterogeneity in the methanation reaction. Advantages of stopped flow over steady state

  3. Nuclear Reactors and Technology

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-01-01

    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.

  4. Fusion reactor materials

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1989-01-01

    This paper discuses the following topics on fusion reactor materials: irradiation, facilities, test matrices, and experimental methods; dosimetry, damage parameters, and activation calculations; materials engineering and design requirements; fundamental mechanical behavior; radiation effects; development of structural alloys; solid breeding materials; and ceramics.

  5. WATER BOILER REACTOR

    Science.gov (United States)

    King, L.D.P.

    1960-11-22

    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.

  6. The First Reactor.

    Science.gov (United States)

    Department of Energy, Washington, DC.

    On December 2, 1942, in a racquet court underneath the West Stands of Stagg Field at the University of Chicago, a team of scientists led by Enrico Fermi created the first controlled, self-sustaining nuclear chain reaction. This updated and revised story of the first reactor (or "pile") is based on postwar interviews (as told to Corbin…

  7. MULTISTAGE FLUIDIZED BED REACTOR

    Science.gov (United States)

    Jonke, A.A.; Graae, J.E.A.; Levitz, N.M.

    1959-11-01

    A multistage fluidized bed reactor is described in which each of a number of stages is arranged with respect to an associated baffle so that a fluidizing gas flows upward and a granular solid downward through the stages and baffles, whereas the granular solid stopsflowing downward when the flow of fluidizing gas is shut off.

  8. Brazilian multipurpose reactor

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2014-07-01

    The Brazilian Multipurpose Reactor (RMB) Project is an action of the Federal Government, through the Ministry of Science Technology and Innovation (MCTI) and has its execution under the responsibility of the Brazilian National Nuclear Energy Commission (CNEN). Within the CNEN, the project is coordinated by the Research and Development Directorate (DPD) and developed through research units of this board: Institute of Nuclear Energy Research (IPEN); Nuclear Engineering Institute (IEN); Centre for Development of Nuclear Technology (CDTN); Regional Center of Nuclear Sciences (CRCN-NE); and Institute of Radiation Protection and Dosimetry (IRD). The Navy Technological Center in Sao Paulo (CTMSP) and also the participation of other research centers, universities, laboratories and companies in the nuclear sector are important and strategic partnerships. The conceptual design and the safety analysis of the reactor and main facilities, related to nuclear and environmental licensing, are performed by technicians of the research units of DPD / CNEN. The basic design was contracted to engineering companies as INTERTHECNE from Brazil and INVAP from Argentine. The research units from DPD/CNEN are also responsible for the design verification on all engineering documents developed by the contracted companies. The construction and installation should be performed by specific national companies and international partnerships. The Nuclear Reactor RMB will be a open pool type reactor with maximum power of 30 MW and have the OPAL nuclear reactor of 20 MW, built in Australia and designed by INVAP, as reference. The RMB reactor core will have a 5x5 configuration, consisting of 23 elements fuels (EC) of U{sub 3}Si{sub 2} dispersion-type Al having a density of up to 3.5 gU/cm{sup 3} and enrichment of 19.75% by weight of {sup 23{sup 5}}U. Two positions will be available in the core for materials irradiation devices. The main objectives of the RMB Reactor and the other nuclear and radioactive

  9. Modeling Chemical Reactors I: Quiescent Reactors

    CERN Document Server

    Michoski, C E; Schmitz, P G

    2010-01-01

    We introduce a fully generalized quiescent chemical reactor system in arbitrary space $\\vdim =1,2$ or 3, with $n\\in\\mathbb{N}$ chemical constituents $\\alpha_{i}$, where the character of the numerical solution is strongly determined by the relative scaling between the local reactivity of species $\\alpha_{i}$ and the local functional diffusivity $\\mathscr{D}_{ij}(\\alpha)$ of the reaction mixture. We develop an operator time-splitting predictor multi-corrector RK--LDG scheme, and utilize $hp$-adaptivity relying only on the entropy $\\mathscr{S}_{\\mathfrak{R}}$ of the reactive system $\\mathfrak{R}$. This condition preserves these bounded nonlinear entropy functionals as a necessarily enforced stability condition on the coupled system. We apply this scheme to a number of application problems in chemical kinetics; including a difficult classical problem arising in nonequilibrium thermodynamics known as the Belousov-Zhabotinskii reaction where we utilize a concentration-dependent diffusivity tensor $\\mathscr{D}_{ij}(...

  10. Alternative approaches to fusion. [reactor design and reactor physics for Tokamak fusion reactors

    Science.gov (United States)

    Roth, R. J.

    1976-01-01

    The limitations of the Tokamak fusion reactor concept are discussed and various other fusion reactor concepts are considered that employ the containment of thermonuclear plasmas by magnetic fields (i.e., stellarators). Progress made in the containment of plasmas in toroidal devices is reported. Reactor design concepts are illustrated. The possibility of using fusion reactors as a power source in interplanetary space travel and electric power plants is briefly examined.

  11. Methodological aspects of a GIS-based environmental health inspection program used in the Athens 2004 Olympic and Para Olympic Games

    Directory of Open Access Journals (Sweden)

    Pantelopoulos Efstathios

    2005-09-01

    Full Text Available Abstract Background The use of geographical information system (GIS technologies in public health surveillance is gradually gaining momentum around the world and many applications have already been reported in the literature. In this study, GIS technology was used to help county departments of Public Health to implement environmental health surveillance for the Athens 2004 Olympic and Para Olympic Games. Methods In order to assess the workload in each Olympic county, 19 registry forms and 17 standardized inspection forms were developed to register and inspect environmental health items requiring inspection (Hotels, restaurants, swimming pools, water supply system etc, respectively. Furthermore, related databases were created using Epi Info 2002 and a geographical information system (GIS were used to implement an integrated Environmental Health inspection program. The project was conducted in Athens by the Olympic Planning Unit (OPU of the National School of Public Health, in close cooperation with the Ministry of Health and Social Solidarity and the corresponding departments of Public Health in all municipalities that were scheduled to host events during the Athens 2004 Olympic and Para Olympic games. Results A total of 44,741 premises of environmental health interest were geocoded into GIS databases and several electronic maps were developed. Using such maps in association with specific criteria, we first identified the maximum workload required to execute environmental health inspections in all premises within the eleven Olympic County Departments of Public Health. Six different scenarios were created for each county, based on devised algorithms in order to design the most effective and realistic inspection program using the available inspectors from each municipality. Furthermore, GIS applications were used to organize the daily inspection program for the Olympic games, provide coloured displays of the inspection results and link those

  12. Development of a Decision Support Tree Approach for Mapping Urban Vegetation Cover From Hyperspectral Imagery and GIS: the case of Athens, Greece

    Science.gov (United States)

    Georgopoulou, Iro; Petropoulos, George P.; Kalivas, Dionissios P.

    2013-04-01

    Urban vegetation represents one of the main factors directly influencing human life. Consequently, extracting information on its spatial distribution is of crucial importance to ensure, between other, sustainable urban planning and successful environmental management. To this end, remote sensing & Geographical Information Systems (GIS) technology has demonstrated a very promising, viable solution. In comparison to multispectral systems, use of hyperspectral imagery in particular, enhances dramatically our ability to accurately identify different targets on the Earth's surface. In our study, a decision tree-based classification method is presented for mapping urban vegetation cover from hyperspectral imagery. The ability of the proposed method is demonstrated using as a case study the city of Athens, Greece, for which satellite hyperspectral imagery from Hyperion sensor has been acquired. Hyperion collects spectral data in 242 spectral bands from visible to middle-infrared regions of electromagnetic spectrum and at a spatial resolution of 30 meters. Validation of our proposed method is carried out on a GIS environment based on the error matrix statistics, using as reference very high resolution imagery acquired nearly concurrently to Hyperion at our study region, supported by field visits conducted in the studied area. Additionally, the urban vegetation cover maps derived from our proposed here technique are compared versus analogous results obtained against other classification methods traditionally used in mapping urban vegetation cover. Our results confirmed the ability of our approach combined with Hyperion imagery to extract urban vegetation cover for the case of a densely-populated city with complex urban features, such as Athens. Our findings can potentially offer significant information at local scale as regards the presence of open green spaces in urban environment, since such information is vital for the successful infrastructure development, urban

  13. Reactor monitoring using antineutrino detectors

    Science.gov (United States)

    Bowden, N. S.

    2011-08-01

    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 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 reactor as part of International Atomic Energy Agency (IAEA) and/or other reactor safeguards regimes. Several efforts to develop this monitoring technique are underway worldwide.

  14. Reactor vessel support system. [LMFBR

    Science.gov (United States)

    Golden, M.P.; Holley, J.C.

    1980-05-09

    A reactor vessel support system includes a support ring at the reactor top supported through a box ring on a ledge of the reactor containment. The box ring includes an annular space in the center of its cross-section to reduce heat flow and is keyed to the support ledge to transmit seismic forces from the reactor vessel to the containment structure. A coolant channel is provided at the outside circumference of the support ring to supply coolant gas through the keyways to channels between the reactor vessel and support ledge into the containment space.

  15. Methanogenesis in Thermophilic Biogas Reactors

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær

    1995-01-01

    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...

  16. Impacts of the solar eclipse of 29 March 2006 on the surface ozone concentration, the solar ultraviolet radiation and the meteorological parameters at Athens, Greece

    Directory of Open Access Journals (Sweden)

    C. Tzanis

    2008-01-01

    Full Text Available In this study the variations in the surface ozone concentration, the solar ultraviolet radiation and the meteorological parameters at the ground before, during and after the total solar eclipse of 29 March 2006 have been examined. This analysis is based on the measurements performed at four stations located in the greater Athens basin in Greece. The experimental data demonstrated that the solar eclipse phenomenon affects the surface ozone concentration as well as the temperature, the relative humidity and the wind speed near the ground. The decrease in the surface ozone concentration that observed after the beginning of the eclipse event lasted almost two hours, probably due to the decreased efficiency of the photochemical ozone formation. The reduction of the solar ultraviolet radiation at 312 and 365 nm reached 97% and 93% respectively, while the air temperature dropped, the relative humidity increased and the wind speed decreased.

  17. Implementation of road and soil dust emission parameterizations in the aerosol model CAMx: Applications over the greater Athens urban area affected by natural sources

    Science.gov (United States)

    Athanasopoulou, E.; Tombrou, M.; Russell, A. G.; Karanasiou, A.; Eleftheriadis, K.; Dandou, A.

    2010-09-01

    A detailed dust emission parameterization was developed for aerosol production by human and natural activity. The road dust scheme includes tire wear, break wear, road abrasion and vehicle-induced re-suspension. The natural dust scheme includes wind (Aeolian) erosion from soil surfaces and land disturbances, and considers the effects of soil and atmospheric parameters on dust productivity. Emission rates are chemically and size-resolved and are incorporated in the CAMx aerosol model coupled with the ISORROPIA II inorganic module. Emissions and concentrations are predicted for five simulation periods, using a domain covering Greece with a fine mesh over the greater Athens area. Re-suspended mass is the main dust component, calculated 4-5 times higher than exhaust emissions. Soil dust emissions are much greater than road dust during high winds but are of less importance inside the city with maximums located at the periphery of the urban core. Comparison with observations suggests that the road dust component seems adequately estimated in traffic-affected areas and accounts for 15-40% of the total PM10. Calcium, regarded as a soil dust tracer, is calculated to be 2-4 μg m-3 in areas with high Aeolian emission rates, similar to measured values. Sodium and magnesium predictions show their marine origin, and reasonably replicate the observed mass and size distribution during well-established onshore flows. Nitrates are predicted as measured during lower winds, but are underestimated when stronger winds prevail from the west. This is caused by an overestimated industrial influence of Athens. As a result, ammonia is bound to the excess of sulfate, rather than reacting with nitric acid. Secondary species are influenced slightly by heterogeneous chemistry on dust particles.

  18. Changes of temperature data for energy studies over time and their impact on energy consumption and CO2 emissions. The case of Athens and Thessaloniki – Greece

    Energy Technology Data Exchange (ETDEWEB)

    Papakostas, K.T.; Michopoulos, A.; Kyriakis, N. [Process Equipment Design Laboratory, Mechanical Engineering Department, Energy Division, Aristotle University of Thessaloniki - 54124 Thessaloniki (Greece); Mavromatis, T. [Department of Meteorology-Climatology, School of Geology, Faculty of Sciences, Aristotle University of Thessaloniki - 54124 Thessaloniki (Greece)

    2013-07-01

    In steady-state methods for estimating energy consumption of buildings, the commonly used data include the monthly average dry bulb temperatures, the heating and cooling degree-days and the dry bulb temperature bin data. This work presents average values of these data for the 1983-1992 and 1993-2002 decades, calculated for Athens and Thessaloniki, determined from hourly dry bulb temperature records of meteorological stations (National Observatory of Athens and Aristotle University of Thessaloniki). The results show that the monthly average dry bulb temperatures and the annual average cooling degree-days of the 1993-2002 decade are increased, compared to those of the 1983-1992 decade, while the corresponding annual average heating degree-days are reduced. Also, the low temperature bins frequency results decreased in the 1993-2002 decade while the high temperature ones increased, compared to the 1983-1992 decade. The effect of temperature data variations on the energy consumption and on CO2 emissions of buildings was examined by calculating the energy demands for heating and cooling and the CO2 emissions from diesel-oil and electricity use of a typical residential building-model. From the study it is concluded that the heating energy requirements during the decade 1993-2002 were decreased, as compared to the energy demands of the decade 1983-1992, while the cooling energy requirements were increased. The variations of CO2 emissions from diesel oil and electricity use were analog to the energy requirements alterations. The results indicate a warming trend, at least for the two regions examined, which affect the estimation of heating and cooling demands of buildings. It, therefore, seems obvious that periodic adaptation of the temperature data used for building energy studies is required.

  19. Road transport emissions and capacity of forests in the region of Athens for sequestring these emissions: carbon flow before and after forest fires

    Directory of Open Access Journals (Sweden)

    Petros Chatzimpiros

    2016-06-01

    Full Text Available One important component of the urban contribution to carbon dioxide atmospheric emissions is road transport. Carbon dioxide (CO2 emissions from urban road transport in the centre of Athens recorded over a period of five years (2000–2005 are compared with the carbon sequestration capacity of regional forests, prior to and after the devastating forest fires in Attica in 2007 and 2009, which is the administrative region of Athens. The comparison of carbon flow reveals two complementary aspects of the same socio-environmental issue: persistent sources versus weakening sinks for CO2 within a mixed (urban and rural setting. Road transport emissions are calculated bottom-up using traffic data from in-situ measurements along segments of main roads. The sequestration capacity of forests is estimated by combining satellite images of changes in land cover with literature values of biomass growth rates. Over the study period, the per capita CO2 emissions averaged 0.72 t CO2/cap/year, which is four times higher than the sequestration capacity of forests before and six times higher after the fires. This imbalance highlights the inadequacy of the local carbon sink. Although there is no biogeochemical need to neutralise carbon budgets locally, defining the CO2 flows from urban activities and local ecosystems is likely to raise awareness and promote global environmental sustainability. The results are compared with top-down estimates of CO2 emissions at a regional scale, where suburban areas are dominant, and the differences are discussed in the light of local socioeconomic factors.

  20. MEANS FOR COOLING REACTORS

    Science.gov (United States)

    Wheeler, J.A.

    1957-11-01

    A design of a reactor is presented in which the fuel elements may be immersed in a liquid coolant when desired without the necessity of removing them from the reactor structure. The fuel elements, containing the fissionable material are in plate form and are disposed within spaced slots in a moderator material, such as graphite to form the core. Adjacent the core is a tank containing the liquid coolant. The fuel elements are mounted in spaced relationship on a rotatable shaft which is located between the core and the tank so that by rotation of the shaft the fuel elements may be either inserted in the slots in the core to sustain a chain reaction or immersed in the coolant.

  1. Compact fusion reactors

    CERN Document Server

    CERN. Geneva

    2015-01-01

    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.

  2. Reactor Neutrino Spectra

    OpenAIRE

    Hayes, A. C.; Vogel, Petr

    2016-01-01

    We present a review of the antineutrino spectra emitted from reactors. Knowledge of these spectra and their associated uncertainties is crucial for neutrino oscillation studies. The spectra used to date have been determined either by converting measured electron spectra to antineutrino spectra or by summing over all of the thousands of transitions that make up the spectra, using modern databases as input. The uncertainties in the subdominant corrections to β-decay plague both methods, and we ...

  3. REACTOR MODERATOR STRUCTURE

    Science.gov (United States)

    Greenstreet, B.L.

    1963-12-31

    A system for maintaining the alignment of moderator block structures in reactors is presented. Integral restraining grids are placed between each layer of blocks in the moderator structure, at the top of the uppermost layer, and at the bottom of the lowermost layer. Slots are provided in the top and bottom surfaces of the moderator blocks so as to provide a keying action with the grids. The grids are maintained in alignment by vertical guiding members disposed about their peripheries. (AEC)

  4. BOILER-SUPERHEATED REACTOR

    Science.gov (United States)

    Heckman, T.P.

    1961-05-01

    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.)

  5. 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)

    2011-07-01

    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)

  6. Thermionic Reactor Design Studies

    Energy Technology Data Exchange (ETDEWEB)

    Schock, Alfred

    1994-06-01

    During the 1960's and early 70's the author performed extensive design studies, analyses, and tests aimed at thermionic reactor concepts that differed significantly from those pursued by other investigators. Those studies, like most others under Atomic Energy Commission (AEC and DOE) and the National Aeronautics and Space Administration (NASA) sponsorship, were terminated in the early 1970's. Some of this work was previously published, but much of it was never made available in the open literature. U.S. interest in thermionic reactors resumed in the early 80's, and was greatly intensified by reports about Soviet ground and flight tests in the late 80's. This recent interest resulted in renewed U.S. thermionic reactor development programs, primarily under Department of Defense (DOD) and Department of Energy (DOE) sponsorship. Since most current investigators have not had an opportunity to study all of the author's previous work, a review of the highlights of that work may be of value to them. The present paper describes some of the author's conceptual designs and their rationale, and the special analytical techniques developed to analyze their performance. The basic designs, first published in 1963, are based on single-cell converters, either double-ended diodes extending over the full height of the reactor core or single-ended diodes extending over half the core height. In that respect they are similar to the thermionic fuel elements employed in the Topaz-2 reactor subsequently developed in the Soviet Union, copies of which were recently imported by the U.S. As in the Topaz-2 case, electrically heated steady-state performance tests of the converters are possible before fueling. Where the author's concepts differed from the later Topaz-2 design was in the relative location of the emitter and the collector. Placing the fueled emitter on the outside of the cylindrical diodes permits much higher axial conductances to reduce ohmic

  7. Turning points in reactor design

    Energy Technology Data Exchange (ETDEWEB)

    Beckjord, E.S.

    1995-09-01

    This article provides some historical aspects on nuclear reactor design, beginning with PWR development for Naval Propulsion and the first commercial application at Yankee Rowe. Five turning points in reactor design and some safety problems associated with them are reviewed: (1) stability of Dresden-1, (2) ECCS, (3) PRA, (4) TMI-2, and (5) advanced passive LWR designs. While the emphasis is on the thermal-hydraulic aspects, the discussion is also about reactor systems.

  8. Fast reactor programme in India

    Indian Academy of Sciences (India)

    P Chellapandi; P R Vasudeva Rao; Prabhat Kumar

    2015-09-01

    Role of fast breeder reactor (FBR) in the Indian context has been discussed with appropriate justification. The FBR programme since 1985 till 2030 is highlighted focussing on the current status and future direction of fast breeder test reactor (FBTR), prototype fast breeder reactor (PFBR) and FBR-1 and 2. Design and technological challenges of PFBR and design and safety targets with means to achieve the same are the major highlights of this paper.

  9. Acceptability of reactors in space

    Energy Technology Data Exchange (ETDEWEB)

    Buden, D.

    1981-04-01

    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.

  10. Spiral-shaped disinfection reactors

    KAUST Repository

    Ghaffour, Noreddine

    2015-08-20

    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.

  11. Hydrogen Production in Fusion Reactors

    OpenAIRE

    Sudo, S.; Tomita, Y.; Yamaguchi, S.; Iiyoshi, A.; Momota, H; Motojima, O.; Okamoto, M.; Ohnishi, M.; Onozuka, M; Uenosono, C.

    1993-01-01

    As one of methods of innovative energy production in fusion reactors without having a conventional turbine-type generator, an efficient use of radiation produced in a fusion reactor with utilizing semiconductor and supplying clean fuel in a form of hydrogen gas are studied. Taking the candidates of reactors such as a toroidal system and an open system for application of the new concepts, the expected efficiency and a concept of plant system are investigated.

  12. Neutrino Oscillation Studies with Reactors

    CERN Document Server

    Vogel, Petr; Zhang, Chao

    2015-01-01

    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.

  13. FAST NEUTRONIC REACTOR

    Science.gov (United States)

    Snell, A.H.

    1957-12-01

    This patent relates to a reactor and process for carrying out a controlled fast neutron chain reaction. A cubical reactive mass, weighing at least 920 metric tons, of uranium metal containing predominantly U/sup 238/ and having a U/sup 235/ content of at least 7.63% is assembled and the maximum neutron reproduction ratio is limited to not substantially over 1.01 by insertion and removal of a varying amount of boron, the reactive mass being substantially freed of moderator.

  14. Biparticle fluidized bed reactor

    Science.gov (United States)

    Scott, C.D.

    1993-12-14

    A fluidized bed reactor system which utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase is described. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary particulate phase, continuously introduced and removed in either cocurrent or countercurrent mode, acts in a secondary role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Introduction and removal of the sorbent phase is accomplished through the use of feed screw mechanisms and multivane slurry valves. 3 figures.

  15. Licensed reactor nuclear safety criteria applicable to DOE reactors

    Energy Technology Data Exchange (ETDEWEB)

    1991-04-01

    The Department of Energy (DOE) Order DOE 5480.6, Safety of Department of Energy-Owned Nuclear Reactors, establishes reactor safety requirements to assure that reactors are sited, designed, constructed, modified, operated, maintained, and decommissioned in a manner that adequately protects health and safety and is in accordance with uniform standards, guides, and codes which are consistent with those applied to comparable licensed reactors. This document identifies nuclear safety criteria applied to NRC (Nuclear Regulatory Commission) licensed reactors. The titles of the chapters and sections of USNRC Regulatory Guide 1.70, Standard Format and Content of Safety Analysis Reports for Nuclear Power Plants, Rev. 3, are used as the format for compiling the NRC criteria applied to the various areas of nuclear safety addressed in a safety analysis report for a nuclear reactor. In each section the criteria are compiled in four groups: (1) Code of Federal Regulations, (2) US NRC Regulatory Guides, SRP Branch Technical Positions and Appendices, (3) Codes and Standards, and (4) Supplemental Information. The degree of application of these criteria to a DOE-owned reactor, consistent with their application to comparable licensed reactors, must be determined by the DOE and DOE contractor.

  16. Reactor Physics Analysis Models for a CANDU Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hang Bok

    2007-10-15

    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.

  17. A Methodology to Validate the InSAR Derived Displacement Field of the September 7th, 1999 Athens Earthquake Using Terrestrial Surveying. Improvement of the Assessed Deformation Field by Interferometric Stacking

    OpenAIRE

    Ioannis Papoutsis; Panagiotis Elias; Spyros Karamitsos; Dimitrios Paradissis; Charalabos Kontoes; Ioannis Kotsis

    2008-01-01

    The primary objective of this paper is the evaluation of the InSAR derived displacement field caused by the 07/09/1999 Athens earthquake, using as reference an external data source provided by terrestrial surveying along the Mornos river open aqueduct. To accomplish this, a processing chain to render comparable the leveling measurements and the interferometric derived measurements has been developed. The distinct steps proposed include a solution for reducing the orbital and atmospheric inter...

  18. Brookhaven leak reactor to close

    CERN Multimedia

    MacIlwain, C

    1999-01-01

    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).

  19. Thermochemical reactor systems and methods

    Energy Technology Data Exchange (ETDEWEB)

    Lipinski, Wojciech; Davidson, Jane Holloway; Chase, Thomas Richard

    2016-11-29

    Thermochemical reactor systems that may be used to produce a fuel, and methods of using the thermochemical reactor systems, utilizing a reactive cylindrical element, an optional energy transfer cylindrical element, an inlet gas management system, and an outlet gas management system.

  20. Chemical-vapor-deposition reactor

    Science.gov (United States)

    Chern, S.

    1979-01-01

    Reactor utilizes multiple stacked trays compactly arranged in paths of horizontally channeled reactant gas streams. Design allows faster and more efficient deposits of film on substrates, and reduces gas and energy consumption. Lack of dead spots that trap reactive gases reduces reactor purge time.

  1. Antineutrino Monitoring of Thorium Reactors

    CERN Document Server

    Akindele, Oluwatomi A; Norman, Eric B

    2015-01-01

    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 fuels 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 (MSR) breed U-233, that if diverted constitute an IAEA direct use material. The antineutrino spectrum from the fission of U-233 has been determined, the feasibility of detecting the diversion of a significant quantity, 8 kg of U-233, within the IAEA timeliness goal of 30 days has been evaluated. The antineutrino emission from a thorium reactor operating under normal conditions is compared to a diversion scenario at a 25 meter standoff by evaluating the daily antineutrino count rate and the energy spectrum of the detected antineutrinos. It was found that the diversion of a signifi...

  2. Engineering reactors for catalytic reactions

    Indian Academy of Sciences (India)

    Vivek V Ranade

    2014-03-01

    Catalytic reactions are ubiquitous in chemical and allied industries. A homogeneous or heterogeneous catalyst which provides an alternative route of reaction with lower activation energy and better control on selectivity can make substantial impact on process viability and economics. 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 discussed. Some examples where performance enhancement was realized by catalyst design, appropriate choice of reactor, better injection and dispersion strategies and recent advances in process intensification/ multifunctional reactors are discussed to illustrate the approach.

  3. Unsteady processes in catalytic reactors

    Energy Technology Data Exchange (ETDEWEB)

    Matros, Yu.Sh.

    1985-01-01

    In recent years a realization has occurred that reaction and reactor dynamics must be considered when designing and operating catalytic reactors. In this book, the author has focussed on both the processes occurring on individual porous-catalyst particles as well as the phenomena displayed by collections of these particles in fixed-bed reactors. The major topics discussed include the effects of unsteady-state heat and mass transfer, the influence of inhomogeneities and stagnant regions in fixed beds, and reactor operation during forced cycling of operating conditions. Despite the title of the book, attention is also paid to the determination of the number and stability of fixed-bed steady states, with the aim of describing the possibility of controlling reactors at unstable steady states. However, this development is somewhat dated, given the recent literature on multiplicity phenomena and process control.

  4. A model of reactor kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, A.S.; Thompson, B.R.

    1988-09-01

    The analytical model of nuclear reactor transients, incorporating both mechanical and nuclear effects, simulates reactor kinetics. Linear analysis shows the stability borderline for small power perturbations. In a stable system, initial power disturbances die out with time. With an unstable combination of nuclear and mechanical characteristics, initial disturbances persist and may increase with time. With large instability, oscillations of great magnitude occur. Stability requirements set limits on the power density at which particular reactors can operate. The limiting power density depends largely on the product of two terms: the fraction of delayed neutrons and the frictional damping of vibratory motion in reactor core components. As the fraction of delayed neutrons is essentially fixed, mechanical damping largely determines the maximum power density. A computer program, based on the analytical model, calculates and plots reactor power as a nonlinear function of time in response to assigned values of mechanical and nuclear characteristics.

  5. Metallic fuels for advanced reactors

    Science.gov (United States)

    Carmack, W. J.; Porter, D. L.; Chang, Y. I.; Hayes, S. L.; Meyer, M. K.; Burkes, D. E.; Lee, C. B.; Mizuno, T.; Delage, F.; Somers, J.

    2009-07-01

    In the framework of the Generation IV Sodium Fast Reactor Program, the Advanced Fuel Project has conducted an evaluation of the available fuel systems supporting future sodium cooled fast reactors. This paper presents an evaluation of metallic alloy fuels. Early US fast reactor developers originally favored metal alloy fuel due to its high fissile density and compatibility with sodium. The goal of fast reactor fuel development programs is to develop and qualify a nuclear fuel system that performs all of the functions of a conventional fast spectrum nuclear fuel while destroying recycled actinides. This will provide a mechanism for closure of the nuclear fuel cycle. Metal fuels are candidates for this application, based on documented performance of metallic fast reactor fuels and the early results of tests currently being conducted in US and international transmutation fuel development programs.

  6. Neutrino Experiments at Reactors

    Science.gov (United States)

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

    1968-09-09

    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.

  7. Neutronic Reactor Shield

    Science.gov (United States)

    Fermi, Enrico; Zinn, Walter H.

    The argument of the present Patent is a radiation shield suitable for protection of personnel from both gamma rays and neutrons. Such a shield from dangerous radiations is achieved to the best by the combined action of a neutron slowing material (a moderator) and a neutron absorbing material. Hydrogen is particularly effective for this shield since it is a good absorber of slow neutrons and a good moderator of fast neutrons. The neutrons slowed down by hydrogen may, then, be absorbed by other materials such as boron, cadmium, gadolinium, samarium or steel. Steel is particularly convenient for the purpose, given its effectiveness in absorbing also the gamma rays from the reactor (both primary gamma rays and secondary ones produced by the moderation of neutrons). In particular, in the present Patent a shield is described, made of alternate layers of steel and Masonite (an hydrolized ligno-cellulose material). The object of the present Patent is not discussed in any other published paper.

  8. Licensed reactor nuclear safety criteria applicable to DOE reactors

    Energy Technology Data Exchange (ETDEWEB)

    1993-11-01

    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.

  9. Reactor service life extension program

    Energy Technology Data Exchange (ETDEWEB)

    Caskey, G.R.; Sindelar, R.L.; Ondrejcin, R.S.; Baumann, E.W.

    1990-12-31

    A review of the Savannah River Site production reactor systems was initiated in 1980 and led to implementation of the Reactor Materials Program in 1984 to assess reactor safety and reactor service life. The program evaluated performance of the reactor tanks, primary coolant piping, and thermal shields, components of welded construction that were fabricated from Type 304 stainless steel. The structural integrity analysis of the primary coolant system has shown that the pressure boundary is not susceptible to gross rupture, including a double ended guillotine break or equivalent large area bank. Residual service life is potentially limited by two material degradation modes, irradiation damage and intergranular stress corrosion cracking. Analysis of the structural integrity of the tanks and piping has shown that continued safe operation of the reactors for several additional decades is not limited by the material performance of the primary coolant system. Although irradiation damage has not degraded material behavior to an unacceptable level, past experience has revealed serious difficulties with repair welding on irradiated stainless steel. Stress corrosion can be mitigated by newly identified limits on impurity concentrations in the coolant water and by stress mitigation of weld residual stresses. Work continues in several areas: the effects of helium on mechanical behavior of irradiated stainless steel; improved weld methods for piping and the reactor tanks; and a surveillance program to track irradiation effects on the tank walls.

  10. Reactor service life extension program

    Energy Technology Data Exchange (ETDEWEB)

    Caskey, G.R.; Sindelar, R.L.; Ondrejcin, R.S.; Baumann, E.W.

    1990-01-01

    A review of the Savannah River Site production reactor systems was initiated in 1980 and led to implementation of the Reactor Materials Program in 1984 to assess reactor safety and reactor service life. The program evaluated performance of the reactor tanks, primary coolant piping, and thermal shields, components of welded construction that were fabricated from Type 304 stainless steel. The structural integrity analysis of the primary coolant system has shown that the pressure boundary is not susceptible to gross rupture, including a double ended guillotine break or equivalent large area bank. Residual service life is potentially limited by two material degradation modes, irradiation damage and intergranular stress corrosion cracking. Analysis of the structural integrity of the tanks and piping has shown that continued safe operation of the reactors for several additional decades is not limited by the material performance of the primary coolant system. Although irradiation damage has not degraded material behavior to an unacceptable level, past experience has revealed serious difficulties with repair welding on irradiated stainless steel. Stress corrosion can be mitigated by newly identified limits on impurity concentrations in the coolant water and by stress mitigation of weld residual stresses. Work continues in several areas: the effects of helium on mechanical behavior of irradiated stainless steel; improved weld methods for piping and the reactor tanks; and a surveillance program to track irradiation effects on the tank walls.

  11. Use of Artificial Burrows by Burrowing Owls (Athene cunicularia) at the HAMMER Facility on the U.S. Department of Energy Hanford Site

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, Amanda K.; Sackschewsky, Michael R.; Duberstein, Corey A.

    2005-09-30

    In 2003 the U.S. Department of Energy (DOE) constructed an Emergency Vehicle Operations Course (EVOC) at the Hazardous Material Management and Emergency Response Training and Education Center (HAMMER) in the southern portion of the Hanford Site. Preliminary surveys during 2001 identified an active burrowing owl (Athene cunicularia) burrow and three burrowing owls within the proposed development area. Burrowing owls were classified as a federal species of concern, a Washington State ?candidate? species, a Washington Department of Fish and Wildlife priority species, and a Hanford Site Biological Resources Management Plan Level III resource. Therefore, the mitigation action plan for the project included the installation of twenty artificial burrows around EVOC in the spring of 2003. The mitigation plan established a success criterion of five percent annual use of the burrows by owls. In July 2005, a field survey of the EVOC burrow complex was conducted to determine use and demography at each site. Burrow locations were mapped and signs of activity (feces, owl tracks, castings, feathers) were recorded. Out of the twenty burrows, twelve were found to be active. Of the eight inactive burrows three appeared to have been active earlier in the 2005 breeding season. A total of nineteen owls were counted but demography could not be determined. It appears that the EVOC mitigation exceeded burrow use goals during 2005. Continued site monitoring and maintenance, according to mitigation plan guidelines should be conducted as prescribed.

  12. 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

    2015-04-01

    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.

  13. Artificial neural network models as a useful tool to forecast human thermal comfort using microclimatic and bioclimatic data in the great Athens area (Greece).

    Science.gov (United States)

    Moustris, Kostas P; Tsiros, Ioannis X; Ziomas, Ioannis C; Paliatsos, Athanasios G

    2010-01-01

    The present study deals with the development and application of Artificial Neural Network (ANN) models as a tool for the evaluation of human thermal comfort conditions in the urban environment. ANNs are applied to forecast for three consecutive days during the hot period of the year (May-September) the human thermal comfort conditions as well as the daily number of consecutive hours with high levels of thermal discomfort in the great area of Athens (Greece). Modeling was based on bioclimatic data calculated by two widely used biometereorogical indices (the Discomfort Index and the Cooling Power Index) and microclimatic data (air temperature, relative humidity and wind speed) from 7 different meteorological stations for the period 2001-2005. Model performance showed that the risk of human discomfort conditions exceeding certain thresholds can be successfully forecasted by the ANN models. In addition, despite the limitations of the models, the results of the study demonstrated that ANNs, when adequately trained, could have a high applicability in the area of prevention human thermal discomfort levels in urban areas, based on a series of relatively limited number of bioclimatic data values calculated prior to the period of interest.

  14. Integrated Green Roofs System and its Role of Achieving Sustainability in Residential Buildings in Urban Area in Athens, Greece and Famagusta, North Cyprus

    Directory of Open Access Journals (Sweden)

    Seyed Mehran shahidipour

    2014-06-01

    Full Text Available In this paper, the characteristics and importance of the green roof in urban area would investigate in some residential buildings in Athens, Greece and then, some strategies give to integrate green roof in residential buildings in Famagusta, north Cyprus due to the importance of energy saving and thermal comfort in residential buildings. These days, sustainable architecture is spreading around the world. Therefore, Sustainable architecture has important role in design buildings and urban design due to high amount of energy use and global warming around the world. There are different methods in sustainable design and one of them that has significant role is design green roof. Green roof integrated to the roof of the buildings to provide the suitable indoor temperature without spending high amount of budget. The methodology is qualitative type that trough the literature review and survey would be understood the importance and role of the green roof in both architecture and urban area. There are many significant architects like Wright that they understood how greenery would improve the function of the building in terms of provide thermal comfort and indoor temperature for the residences, and green roof as well. In Famagusta, there is not any green roof however, the design and integrating of green roof is inexpensive. Green roof should design properly depend on the characteristic of the climate of every place so, the location, temperature, and humidity, location, and wind have influence on the design of the green roof.

  15. 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.

    Science.gov (United States)

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

    2014-02-01

    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), paraben (100%), 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.

  16. 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

    2006-12-01

    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.

  17. Assessment of torsatrons as reactors

    Energy Technology Data Exchange (ETDEWEB)

    Lyon, J.F. (Oak Ridge National Lab., TN (United States)); Painter, S.L. (Australian National Univ., Canberra, ACT (Australia))

    1992-12-01

    Stellarators have significant operational advantages over tokamaks as ignited steady-state reactors because stellarators have no dangerous disruptions and no need for continuous current drive or power recirculated to the plasma, both easing the first wall, blanket, and shield design; less severe constraints on the plasma parameters and profiles; and better access for maintenance. This study shows that a reactor based on the torsatron configuration (a stellarator variant) could also have up to double the mass utilization efficiency (MUE) and a significantly lower cost of electricity (COE) than a conventional tokamak reactor (ARIES-I) for a range of assumptions. Torsatron reactors can have much smaller coil systems than tokamak reactors because the coils are closer to the plasma and they have a smaller cross section (higher average current density because of the lower magnetic field). The reactor optimization approach and the costing and component models are those used in the current stage of the ARIES-I tokamak reactor study. Typical reactor parameters for a 1-GW(e) Compact Torsatron reactor example are major radius R[sub 0] = 6.6-8.8 m, on-axis magnetic field B[sup 0] = 4.8-7.5 T, B[sub max] (on coils) = 16 T, MUE 140-210 kW(e)/tonne, and COE (in constant 1990 dollars) = 67-79 mill/kW(e)h. The results are relatively sensitive to assumptions on the level of confinement improvement and the blanket thickness under the inboard half of the helical windings but relatively insensitive to other assumptions.

  18. Concept for LEU Burst Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Steven Karl [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kimpland, Robert Herbert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-07

    Design and performance of a proposed LEU burst reactor are sketched. Salient conclusions reached are the following: size would be ~1,500 kg or greater, depending on the size of the central cavity; internal stresses during burst require split rings for relief; the reactor would likely require multiple control and safety rods for fine control; the energy spectrum would be comparable to that of HEU machines; and burst yields and steady-state power levels will be significantly greater in an LEU reactor.

  19. Nuclear reactor downcomer flow deflector

    Energy Technology Data Exchange (ETDEWEB)

    Gilmore, Charles B. (Greensburg, PA); Altman, David A. (Pittsburgh, PA); Singleton, Norman R. (Murrysville, PA)

    2011-02-15

    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.

  20. Safety of VVER-440 reactors

    CERN Document Server

    Slugen, Vladimir

    2011-01-01

    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

  1. Random processes in nuclear reactors

    CERN Document Server

    Williams, M M R

    1974-01-01

    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

  2. Fuel Fabrication and Nuclear Reactors

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-02-02

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-15

    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)

  4. 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)

    2016-02-29

    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.

  5. ADAPTIVE CONTROL SYSTEM OF INDUSTRIAL REACTORS

    Directory of Open Access Journals (Sweden)

    Vyacheslav K. Mayevski

    2014-01-01

    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.

  6. 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)

    2016-03-31

    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.

  7. Breeder Reactors, Understanding the Atom Series.

    Science.gov (United States)

    Mitchell, Walter, III; Turner, Stanley E.

    The theory of breeder reactors in relationship to a discussion of fission is presented. Different kinds of reactors are characterized by the cooling fluids used, such as liquid metal, gas, and molten salt. The historical development of breeder reactors over the past twenty-five years includes specific examples of reactors. The location and a brief…

  8. Evolution of the tandem mirror reactor concept

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, G.A.; Logan, B.G.

    1982-03-09

    We discuss the evolution of the tandem mirror reactor concept from the original conceptual reactor design (1977) through the first application of the thermal barrier concept to a reactor design (1979) to the beginning of the Mirror Advanced Reactor Study (1982).

  9. 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

    2003-07-01

    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)

  10. Advanced Catalytic Hydrogenation Retrofit Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Reinaldo M. Machado

    2002-08-15

    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.

  11. Advanced Carbothermal Electric Reactor Project

    Data.gov (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...

  12. 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.

    1989-12-01

    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)

  13. Unique features of space reactors

    Science.gov (United States)

    Buden, David

    Space reactors are designed to meet a unique set of requirements; they must be sufficiently compact to be launched in a rocket to their operational location, operate for many years without maintenance and servicing, operate in extreme environments, and reject heat by radiation to space. To meet these restrictions, operating temperatures are much greater than in terrestrial power plants, and the reactors tend to have a fast neutron spectrum. Currently, a new generation of space reactor power plants is being developed. The major effort is in the SP-100 program, where the power plant is being designed for seven years of full power, and no maintenance operation at a reactor outlet operating temperature of 1350 K.

  14. Thermal Analysis for Mobile Reactor

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Mobile reactor design in the paper is consisted of two grades of thermal electric conversion. The first grade is the thermionic conversion inside the core and the second grade is thermocouple conversion

  15. Teaching About Nature's Nuclear Reactors

    CERN Document Server

    Herndon, J M

    2005-01-01

    Naturally occurring nuclear reactors existed in uranium deposits on Earth long before Enrico Fermi built the first man-made nuclear reactor beneath Staggs Field in 1942. In the story of their discovery, there are important lessons to be learned about scientific inquiry and scientific discovery. Now, there is evidence to suggest that the Earth's magnetic field and Jupiter's atmospheric turbulence are driven by planetary-scale nuclear reactors. The subject of planetocentric nuclear fission reactors can be a jumping off point for stimulating classroom discussions about the nature and implications of planetary energy sources and about the geomagnetic field. But more importantly, the subject can help to bring into focus the importance of discussing, debating, and challenging current thinking in a variety of areas.

  16. Advanced Carbothermal Electric Reactor Project

    Data.gov (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...

  17. Solid State Reactor Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Mays, G.T.

    2004-03-10

    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

  18. Microchannel Reactors for ISRU Applications

    Science.gov (United States)

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

    2005-02-01

    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.

  19. Reactor antineutrinos and nuclear physics

    Science.gov (United States)

    Balantekin, A. B.

    2016-11-01

    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.

  20. Reactor Simulator Testing

    Science.gov (United States)

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

    2013-01-01

    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.

  1. Novel Catalytic Membrane Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Stuart Nemser, PhD

    2010-10-01

    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.

  2. LMFBR type reactor

    Energy Technology Data Exchange (ETDEWEB)

    Iwashige, Kengo

    1996-06-21

    In an LMFBR type reactor, partitions are disposed to a coolant channel at positions lower than the free liquid level, and the width of the partitions is adapted to have a predetermined condition. Namely, when low temperature fluid overflowing the wall of the coolant channel, flows down and collided against the free liquid surface in the coolant channel, since the dropping speed thereof is reduced abruptly, large pressure waves are caused by kinetic force of the low temperature fluid. However, if appropriate numbers of partitions having an appropriate shape are formed, the dropping speed of the low temperature fluid is moderated to reduce the pressure waves. In addition, since the pressure waves are dispersed to the circumferential and lateral directions of the coolant flow channel respectively, the propagation of the pressure waves can be prevented effectively. Further, when the flow of the low temperature fluid is changed to the circumferential direction, for example, by earthquakes, since the partitions act as members resisting against the circumferential change of the low temperature fluid, the change of the direction can be suppressed. (N.H.)

  3. Calculation of reactor antineutrino spectra in TEXONO

    CERN Document Server

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

    2002-01-01

    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

  4. Tritium management in fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Galloway, T.R.

    1978-05-01

    This is a review paper covering the key environmental and safety issues and how they have been handled in the various magnetic and inertial confinement concepts and reference designs. The issues treated include: tritium accident analyses, tritium process control, occupational safety, HTO formation rate from the gas-phase, disposal of tritium contaminated wastes, and environmental impact--each covering the Joint European Tokamak (J.E.T. experiment), Tokamak Fusion Test Reactor (TFTR), Russian T-20, The Next Step (TNS) designs by Westinghouse/ORNL and General Atomic/ANL, the ANL and ORNL EPR's, the G.A. Doublet Demonstration Reactor, the Italian Fintor-D and the ORNL Demo Studies. There are also the following full scale plant reference designs: UWMAK-III, LASL's Theta Pinch Reactor Design (RTPR), Mirror Fusion Reactor (MFR), Tandem Mirror Reactor (TMR), and the Mirror Hybrid Reactor (MHR). There are four laser device breakeven experiments, SHIVA-NOVA, LLL reference designs, ORNL Laser Fusion power plant, the German ''Saturn,'' and LLL's Laser Fusion EPR I and II.

  5. Innovative hybrid biological reactors using membranes; Reactores biologico hibrido innovadores utilizando membranas

    Energy Technology Data Exchange (ETDEWEB)

    Diez, R.; Esteban-Garcia, A. L.; Florio, L. de; Rodriguez-Hernandez, L.; Tejero, I.

    2011-07-01

    In this paper we present two lines of research on hybrid reactors including the use of membranes, although with different functions: RBPM, biofilm reactors and membranes filtration RBSOM, supported biofilm reactors and oxygen membranes. (Author) 14 refs.

  6. Establishment of licensing process for development reactors

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Jong Chull; Yune, Young Gill; Kim, Woong Sik (and others)

    2006-02-15

    A study on licensing processes for development reactors has been performed to prepare the licensing of development reactors developed in Korea. The contents and results of the study are summarized as follows. The licensing processes for nuclear reactors in Korea, U.S.A., Japan, France, U.K., Canada, and IAEA were surveyed and analyzed to obtain technical bases necessary for establishing licensing processes applicable to development reactors in Korea. Based on the technical bases obtained the above analysis, the purpose, power output, and design characteristics of development reactors were analyzed in detail. The analysis results suggested that development reactors should be classified as a new reactor category (called as 'development reactor') separated from the current reactor categories such as the research reactor and the power reactor. Therefore, it is proposed to establish a new reactor category classified as 'development reactor' for the development reactors. And licensing processes, including licensing technical requirements, licensing document requirements, and other regulatory requirements, were also proposed for the development reactors. In order to institutionalize the licensing processes developed in this study, it is necessary to revise the current laws. Therefore, draft provisions of Atomic Energy Act, Enforcement Decree of the Atomic Energy Act, and Enforcement Regulation of the Atomic Energy Act have been developed for the preparation of the future legalization of the licensing processes proposed for the development reactors. Conclusively, a proposal of licensing processes and draft provisions of laws have been developed for the development reactors. The results proposed in this study can be applied directly to the licensing of the future development reactors. Furthermore, they will also contribute to establishing successfully the licensing processes of the development reactors.

  7. 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)

    2001-07-15

    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)

  8. Reactor Simulator Testing

    Science.gov (United States)

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

    2013-01-01

    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. Keywords: fission, space power, nuclear, liquid metal, NaK.

  9. Comparison of the Diet of Two Desert-living Owls, the Long-eared Owl ( Asio otus and Little Owl ( Athene noctua from Southern Mongolia

    Directory of Open Access Journals (Sweden)

    Dawn M. Scott

    2005-06-01

    Full Text Available The diet of two sympatric owl species, the long-eared owl ( Asio otus and the little owl ( Athene noctua was investigated in an arid area of southern Mongolia using pellet analysis. In total 334 pellets of long-eared owl and 52 pellets of little owl were analysed, revealing the presence of five small mammal species (Dipodidae, three Muridae and one Soricidae, small birds and invertebrate fragments. Accumulative composition plots indicated a batch size of 35 - 60 pellets was sufficient to reveal representative diet composition. Small mammals comprised the largest component of the diet of long- eared owls with four species recorded, Phodopus was the most frequently occurring (85 %, followed by Meriones (33 %. Bird and invertebrate remains were also found in long-eared owl pellets but comprised less than 2 %. In contrast, invertebrates were the highest occurring component of the diet of little owls (35 %, with small mammals occurring in only 40 % of pellets. Meriones was the most frequently recorded small mammal in little owl pellets (23 % and contributed the greatest in terms of overall rodent biomass. There was a highly statistically significant difference in the diet of the two species (÷ 2 = 2043, d.f. = 4, P < 0.001. Levin’s measure of niche breadth was greater for little owls (0.71 than long-eared owls (0.51, but overall the two species had low niche overlap using Levin’s index (0.22. These results are discussed in relation to previous findings of these two species.

  10. Roost and diet selection by Southern Spotted Owlet Athene brama brama (Temminck, 1821 in the Cauvery Delta of Nagapattinam District, southern India

    Directory of Open Access Journals (Sweden)

    V. Vanitha

    2014-06-01

    Full Text Available The Spotted Owlet Athene brama is the commonest among the 62 species of owls of India and also a widely distributed bio-control agent of agricultural pests in India. We studied the roost site selection and diet composition of the Southern Spotted Owlet A.b. brama in the Cauvery Delta in southern India during 2007-08. The roost selection evaluated based on roost site characteristics observed from 22 roost sites revealed that the owlets preferred to roost closer to human habitation than in agricultural fields, with all the roosts found among trees. Albizia saman (Rain Tree was the most commonly used roost tree species. Tree species with 20-30 m height and 1-3 m gbh were most preferred for roosting due to the presence of a greater number of branches. Roost species and size class selection appeared to depend on availability of suitable locations with better protection from weather and concealment to avoid disturbance from humans and other birds. Diet composition examined through analysis of 55 regurgitated pellets revealed that undigested food items from insects constituted the bulk of the owls diet (57% followed by mammals (rodents (24.4%, reptiles (7.8% and birds (7.3%. However, it is argued that mammals in the form of digestible parts could have contributed more to the diet of the owlet than any other taxa. Higher consumption of rodents and insects is discussed in the light of reducing agricultural pests; adequate roosting sites (mature trees and creating awareness among the local community about the role of Spotted Owlets will improve their population and help control agricultural pests more effectively.

  11. Modelling effects of chemical exposure on birds wintering in agricultural landscapes: The western burrowing owl (Athene cunicularia hypugaea) as a case study

    Science.gov (United States)

    Engelman, Catherine A.; Grant, William E.; Mora, Miguel A.; Woodin, Marc

    2012-01-01

    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

  12. Modelling effects of chemical exposure on birds wintering in agricultural landscapes: The western burrowing owl (Athene cunicularia hypugaea) as a case study

    Science.gov (United States)

    Engelman, C.A.; Grant, W.E.; Mora, M.A.; Woodin, M.

    2012-01-01

    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

  13. Reactivity determination in accelerator driven reactors using reactor noise analysis

    Directory of Open Access Journals (Sweden)

    Kostić Ljiljana 1

    2002-01-01

    Full Text Available Feynman-alpha and Rossi-alpha methods are used in traditional nuclear reactors to determine the subcritical reactivity of a system. The methods are based on the measurement of the mean value, variance and the covariance of detector counts for different measurement times. Such methods attracted renewed attention recently with the advent of the so-called accelerator driven reactors (ADS proposed some time ago. The ADS systems, intended to be used either in energy generation or transuranium transmutation, will use a subcritical core with a strong spallation source. A spallation source has statistical properties that are different from those traditionally used by radioactive sources. In such reactors the monitoring of the subcritical reactivity is very important, and a statistical method, such as the Feynman-alpha method, is capable of resolving this problem.

  14. Heterogeneous Transmutation Sodium Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    S. E. Bays

    2007-09-01

    The threshold-fission (fertile) nature of Am-241 is used to destroy this minor actinide by capitalizing upon neutron capture instead of fission within a sodium fast reactor. This neutron-capture and its subsequent decay chain leads to the breeding of even neutron number plutonium isotopes. A slightly moderated target design is proposed for breeding plutonium in an axial blanket located above the active “fast reactor” driver fuel region. A parametric study on the core height and fuel pin diameter-to-pitch ratio is used to explore the reactor and fuel cycle aspects of this design. This study resulted in both non-flattened and flattened core geometries. Both of these designs demonstrated a high capacity for removing americium from the fuel cycle. A reactivity coefficient analysis revealed that this heterogeneous design will have comparable safety aspects to a homogeneous reactor of comparable size. A mass balance analysis revealed that the heterogeneous design may reduce the number of fast reactors needed to close the current once-through light water reactor fuel cycle.

  15. Thermonuclear Reflect AB-Reactor

    CERN Document Server

    Bolonkin, Alexander

    2008-01-01

    The author offers a new kind of thermonuclear reflect reactor. The remarkable feature of this new reactor is a three net AB reflector, which confines the high temperature plasma. The plasma loses part of its energy when it contacts with the net but this loss can be compensated by an additional permanent plasma heating. When the plasma is rarefied (has a small density), the heat flow to the AB reflector is not large and the temperature in the triple reflector net is lower than 2000 - 3000 K. This offered AB-reactor has significantly less power then the currently contemplated power reactors with magnetic or inertial confinement (hundreds-thousands of kW, not millions of kW). But it is enough for many vehicles and ships and particularly valuable for tunnelers, subs and space apparatus, where air to burn chemical fuel is at a premium or simply not available. The author has made a number of innovations in this reactor, researched its theory, developed methods of computation, made a sample computation of typical pr...

  16. Imaging Fukushima Daiichi reactors with muons

    Directory of Open Access Journals (Sweden)

    Haruo Miyadera

    2013-05-01

    Full Text Available A study of imaging the Fukushima Daiichi reactors with cosmic-ray muons to assess the damage to the reactors is presented. Muon scattering imaging has high sensitivity for detecting uranium fuel and debris even through thick concrete walls and a reactor pressure vessel. Technical demonstrations using a reactor mockup, detector radiation test at Fukushima Daiichi, and simulation studies have been carried out. These studies establish feasibility for the reactor imaging. A few months of measurement will reveal the spatial distribution of the reactor fuel. The muon scattering technique would be the best and probably the only way for Fukushima Daiichi to make this determination in the near future.

  17. Fast breeder reactors an engineering introduction

    CERN Document Server

    Judd, A M

    1981-01-01

    Fast Breeder Reactors: An Engineering Introduction is an introductory text to fast breeder reactors and covers topics ranging from reactor physics and design to engineering and safety considerations. Reactor fuels, coolant circuits, steam plants, and control systems are also discussed. This book is comprised of five chapters and opens with a brief summary of the history of fast reactors, with emphasis on international and the prospect of making accessible enormous reserves of energy. The next chapter deals with the physics of fast reactors and considers calculation methods, flux distribution,

  18. 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

    2012-02-01

    Full Text Available Anastasios John KanellopoulosLaservision.gr 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

  19. Plasma reactor waste management systems

    Science.gov (United States)

    Ness, Robert O., Jr.; Rindt, John R.; Ness, Sumitra R.

    1992-01-01

    The University of North Dakota is developing a plasma reactor system for use in closed-loop processing that includes biological, materials, manufacturing, and waste processing. Direct-current, high-frequency, or microwave discharges will be used to produce plasmas for the treatment of materials. The plasma reactors offer several advantages over other systems, including low operating temperatures, low operating pressures, mechanical simplicity, and relatively safe operation. Human fecal material, sunflowers, oats, soybeans, and plastic were oxidized in a batch plasma reactor. Over 98 percent of the organic material was converted to gaseous products. The solids were then analyzed and a large amount of water and acid-soluble materials were detected. These materials could possibly be used as nutrients for biological systems.

  20. Nuclear Reactor Engineering Analysis Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Carlos Chavez-Mercado; Jaime B. Morales-Sandoval; Benjamin E. Zayas-Perez

    1998-12-31

    The Nuclear Reactor Engineering Analysis Laboratory (NREAL) is a sophisticated computer system with state-of-the-art analytical tools and technology for analysis of light water reactors. Multiple application software tools can be activated to carry out different analyses and studies such as nuclear fuel reload evaluation, safety operation margin measurement, transient and severe accident analysis, nuclear reactor instability, operator training, normal and emergency procedures optimization, and human factors engineering studies. An advanced graphic interface, driven through touch-sensitive screens, provides the means to interact with specialized software and nuclear codes. The interface allows the visualization and control of all observable variables in a nuclear power plant (NPP), as well as a selected set of nonobservable or not directly controllable variables from conventional control panels.

  1. Utilisation of thorium in reactors

    Science.gov (United States)

    Anantharaman, K.; Shivakumar, V.; Saha, D.

    2008-12-01

    India's nuclear programme envisages a large-scale utilisation of thorium, as it has limited deposits of uranium but vast deposits of thorium. The large-scale utilisation of thorium requires the adoption of closed fuel cycle. The stable nature of thoria and the radiological issues associated with thoria poses challenges in the adoption of a closed fuel cycle. A thorium fuel based Advanced Heavy Water Reactor (AHWR) is being planned to provide impetus to development of technologies for the closed thorium fuel cycle. Thoria fuel has been loaded in Indian reactors and test irradiations have been carried out with (Th-Pu) MOX fuel. Irradiated thorium assemblies have been reprocessed and the separated 233U fuel has been used for test reactor KAMINI. The paper highlights the Indian experience with the use of thorium and brings out various issues associated with the thorium cycle.

  2. A tubular focused sonochemistry reactor

    Institute of Scientific and Technical Information of China (English)

    ZHOU GuangPing; LIANG ZhaoFeng; LI ZhengZhong; ZHANG YiHui

    2007-01-01

    This paper presents a new sonochemistry reactor, which consists of a cylindrical tube with a certain length and piezoelectric transducers at tube's end with the longitudinal vibration. The tube can effectively transform the longitudinal vibration into the radial vibration and thereby generates ultrasound. Furthermore, ultrasound can be focused to form high-intensity ultrasonic field inside tube. The reactor boasts of simple structure and its whole vessel wall can radiate ultrasound so that the electroacoustic transfer efficiency is high. The focused ultrasonic field provides good condition for sonochemical reaction. The length of the reactor can be up to 2 meters, and liquids can pass through it continuously, so it can be widely applied in liquid processing such as sonochemistry.

  3. A compact Tokamak transmutation reactor

    Institute of Scientific and Technical Information of China (English)

    QiuLi-Jian; XiaoBing-Jia

    1997-01-01

    The low aspect ration tokamak is proposed for the driver of a transmutation reactor.The main parameters of the reactor core,neutronic analysis of the blanket are given>the neutron wall loading can be lowered from the magnitude order of 1 MW/m2 to 0.5MW/m2 which is much easier to reach in the near future,and the transmutation efficiency (fission/absorption ratio)is raised further.The blanket power density is about 200MW/m3 which is not difficult to deal with.The key components such as diverter and center conductor post are also designed and compared with conventional TOkamak,Finally,by comparison with the other drivers such as FBR,PWR and accelerator,it can be anticipated that the low aspect ratio transmutation reactor would be one way of fusion energy applications in the near future.

  4. 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

    1955-02-11

    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.

  5. Fundamentals of Nuclear Reactor Physics

    CERN Document Server

    Lewis, E E

    2008-01-01

    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

  6. PITR: Princeton Ignition Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    1978-12-01

    The principal objectives of the PITR - Princeton Ignition Test Reactor - are to demonstrate the attainment of thermonuclear ignition in deuterium-tritium, and to develop optimal start-up techniques for plasma heating and current induction, in order to determine the most favorable means of reducing the size and cost of tokamak power reactors. This report describes the status of the plasma and engineering design features of the PITR. The PITR geometry is chosen to provide the highest MHD-stable values of beta in a D-shaped plasma, as well as ease of access for remote handling and neutral-beam injection.

  7. Analysis of Adiabatic Batch Reactor

    Directory of Open Access Journals (Sweden)

    Erald Gjonaj

    2016-05-01

    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.

  8. External fuel thermionic reactor system.

    Science.gov (United States)

    Mondt, J. F.; Peelgren, M. L.

    1971-01-01

    Thermionic reactors are prime candidates for nuclear electric propulsion. The national thermionic reactor effort is concentrated on the flashlight concept with the external-fuel concept as the backup. The external-fuel concept is very adaptable to a completely modular power subsystem which is attractive for highly reliable long-life applications. The 20- to 25-cm long, externally-fueled converters have been designed, fabricated, and successfully tested with many thermal cycles by electrical heating. However, difficulties have been encountered during encapsulation for nuclear heated tests and none have been started to date. These nuclear tests are required to demonstrate the concept feasibility.

  9. Reactor shutdown delays medical procedures

    Science.gov (United States)

    Gwynne, Peter

    2008-01-01

    A longer-than-expected maintenance shutdown of the Canadian nuclear reactor that produces North America's entire supply of molybdenum-99 - from which the radioactive isotopes technetium-99 and iodine-131 are made - caused delays to the diagnosis and treatment of thousands of seriously ill patients last month. Technetium-99 is a key component of nuclear-medicine scans, while iodine-131 is used to treat cancer and other diseases of the thyroid. Production eventually resumed, but only after the Canadian government had overruled the Canadian Nuclear Safety Commission (CNSC), which was still concerned about the reactor's safety.

  10. 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

    2005-04-28

    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.

  11. Oregon State University TRIGA Reactor annual report

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, T.V.; Johnson, A.G.; Bennett, S.L.; Ringle, J.C.

    1979-08-31

    The use of the Oregon State University TRIGA Reactor during the year ending June 30, 1979, is summarized. Environmental and radiation protection data related to reactor operation and effluents are included.

  12. Reactor Antineutrino Signals at Morton and Boulby

    CERN Document Server

    Dye, Steve

    2016-01-01

    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...

  13. Transmutation of actinides in power reactors.

    Science.gov (United States)

    Bergelson, B R; Gerasimov, A S; Tikhomirov, G V

    2005-01-01

    Power reactors can be used for partial short-term transmutation of radwaste. This transmutation is beneficial in terms of subsequent storage conditions for spent fuel in long-term storage facilities. CANDU-type reactors can transmute the main minor actinides from two or three reactors of the VVER-1000 type. A VVER-1000-type reactor can operate in a self-service mode with transmutation of its own actinides.

  14. Food habits and prey spectrum of Spotted Owlet (Athene brama) in Madurai District, Tamil Nadu, southern India%印度泰米尔纳德邦马杜赖地区横斑腹小鸮(Athene brama)的食性及猎物谱

    Institute of Scientific and Technical Information of China (English)

    Ramachandran SANTHANAKRISHNAN; Abdul Hameed MOHAMED SAMSOOR ALI; Uthirapathi ANBARASAN

    2011-01-01

    我们于2007年至2009年通过食丸分析研究了印度泰米尔纳德邦马杜赖地区横斑腹小鸮(Athene brama)的食性及猎物谱.共分析了食丸4181个,记录了共16种猎物的40278个残余物.每个食丸中的猎物种类为1-31个,平均9.6±3.03个.分析表明,该地区横斑腹小鸮的主要猎物为无脊椎动物(昆虫类占83.0%,蛛形类占1.1%,多足类占0.2%),其次为脊椎动物(爬行类占3.3%,哺乳类占2.9%).哺乳类猎物主要包括各种小家鼠(Mus spp.)、黑家鼠(Rattus rattus)、臭鼩鼱(Suncus murinus)、印度沙鼠(Tatera indica)、小板齿鼠(Bandicota bengalenais)及小型翼手类动物.

  15. Laminar Entrained Flow Reactor (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2014-02-01

    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.

  16. Some new viewpoints in reactor noise analysis

    Institute of Scientific and Technical Information of China (English)

    罗征培; 李富; 等

    1996-01-01

    It is propsed that the linearity criterion and order criterion via frequency spectrum features without any limitation of the model's phase can be used in reactor noise analysis.The time constant,natural frequency as well as the recovered transfer function of reactors can bhe obtained via the analyzable model based on reactor noise.

  17. Heat-pipe thermionic reactor concept

    DEFF Research Database (Denmark)

    Storm Pedersen, E.

    1967-01-01

    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...

  18. Heavy Water Reactor; Reacteurs a eau lourde

    Energy Technology Data Exchange (ETDEWEB)

    Yu, St.; HOpwood, J.; Meneley, D. [Energie Atomique du Canada (Canada)

    2000-04-01

    This document deals with the Heavy Water Reactor (HWR) technology and especially the Candu (Canada Deuterium Uranium) reactor. This reactors type offers many advantages that promote them for the future. General concepts, a description of the Candu nuclear power plants, the safety systems, the fuel cycle and economical and environmental aspects are included. (A.L.B.)

  19. Operating Modes Of Chemical Reactors Of Polymerization

    Directory of Open Access Journals (Sweden)

    Meruyert Berdieva

    2012-05-01

    Full Text Available In the work the issues of stable technological modes of operation of main devices of producing polysterol reactors have been researched as well as modes of stable operation of a chemical reactor have been presented, which enables to create optimum mode parameters of polymerization process, to prevent emergency situations of chemical reactor operation in industrial conditions.

  20. Nuclear Reactors and Technology; (USA)

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-01-01

    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.

  1. A Simple Tubular Reactor Experiment.

    Science.gov (United States)

    Hudgins, Robert R.; Cayrol, Bertrand

    1981-01-01

    Using the hydrolysis of crystal violet dye by sodium hydroxide as an example, the theory, apparatus, and procedure for a laboratory demonstration of tubular reactor behavior are described. The reaction presented can occur at room temperature and features a color change to reinforce measured results. (WB)

  2. Silica-Immobilized Enzyme Reactors

    Science.gov (United States)

    2007-08-01

    immobilized artificial membrane chromatography and lysophospholipid micellar electrokinetic chromatography . J. Chromatogr. A 1998, 810, 95-103. 50...Journal of Liquid Chromatography and Related Technologies. Air Force Research Laboratory Materials and Manufacturing Directorate Airbase...immobilized enzyme reactors (IMERs) can also be integrated directly to further analytical methods such as liquid chromatography or mass spectrometry.[6] In

  3. British high flux beam reactor.

    Science.gov (United States)

    Egelstaff, P A

    1970-10-24

    The neutron scattering technique has become an accepted method for the study of condensed matter. Because of the great scientific and technical value of neutron experiments and the growing body of users, several proposals have been made during the past decade for a nuclear reactor devoted primarily to this technique. This article reviews the reasons for and history behind these proposals.

  4. Nuclear reactors and fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2014-07-01

    The Nuclear Fuel Center (CCN) of IPEN produces nuclear fuel for the continuous operation of the IEA-R1 research reactor of IPEN. The serial production started in 1988, when the first nuclear fuel element was delivered for IEA-R1. In 2011, CCN proudly presents the 100{sup th} nuclear fuel element produced. Besides routine production, development of new technologies is also a permanent concern at CCN. In 2005, U{sub 3}O{sub 8} were replaced by U{sub 3}Si{sub 2}-based fuels, and the research of U Mo is currently under investigation. Additionally, the Brazilian Multipurpose Research Reactor (RMB), whose project will rely on the CCN for supplying fuel and uranium targets. Evolving from an annual production from 10 to 70 nuclear fuel elements, plus a thousand uranium targets, is a huge and challenging task. To accomplish it, a new and modern Nuclear Fuel Factory is being concluded, and it will provide not only structure for scaling up, but also a safer and greener production. The Nuclear Engineering Center has shown, along several years, expertise in the field of nuclear, energy systems and correlated areas. Due to the experience obtained during decades in research and technological development at Brazilian Nuclear Program, personnel has been trained and started to actively participate in design of the main system that will compose the Brazilian Multipurpose Reactor (RMB) which will make Brazil self-sufficient in production of radiopharmaceuticals. The institution has participated in the monitoring and technical support concerning the safety, licensing and modernization of the research reactors IPEN/MB-01 and IEA-R1. Along the last two decades, numerous specialized services of engineering for the Brazilian nuclear power plants Angra 1 and Angra 2 have been carried out. The contribution in service, research, training, and teaching in addition to the development of many related technologies applied to nuclear engineering and correlated areas enable the institution to

  5. Tropospheric Vertical Profiles of Aerosol Optical, Microphysical and Concentration Properties in the Frame of the Hygra-CD Campaign (Athens, Greece 2014: A Case Study of Long-Range Transport of Mixed Aerosols

    Directory of Open Access Journals (Sweden)

    Papayannis Alexandros

    2016-01-01

    Full Text Available Combined multi-wavelength aerosol Raman lidar and sun photometry measurements were performed during the HYGRA-CD campaign over Athens, Greece during May-June 2014. The retrieved aerosol optical properties (3 aerosol backscatter at 355-532-1064 nm and 2 aerosol extinction profiles at 355-532 nm were used as input to an inversion code to retrieve the aerosol microphysical properties (effective radius reff and number concentration N using regularization techniques. Additionally, the volume concentration profile was derived for fine particles using the LIRIC code. In this paper we selected a complex case study of long-range transport of mixed aerosols (biomass burning particles mixed with dust arriving over Athens between 10-12 June 2014 in the 1.5-4 km height. Between 2-3 km height we measured mean lidar ratios (LR ranging from 45 to 58 sr (at 355 and 532 nm, while the Ångström exponent (AE aerosol extinction-related values (355nm/532nm ranged between 0.8-1.3. The retrieved values of reff and N ranged from 0.19±0.07 to 0.22±0.07 μm and 460±230 to 2200±2800 cm-3, respectively. The aerosol linear depolarization ratio (δ at 532 nm was lower than 5-7% (except for the Saharan dust cases, where δ~10-15%.

  6. Heterogeneous Recycling in Fast Reactors

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-07-30

    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.

  7. A new MTR fuel for a new MTR reactor: UMo for the Jules Horowitz reactor

    Energy Technology Data Exchange (ETDEWEB)

    Guigon, B. [CEA Cadarache, F-13108 Saint Paul lez Durance (France); Vacelet, H. [CERCA, Romans (France); Dornbusch, D. [Technicatome, Aix en Provence (France)

    2000-07-01

    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 the main characteristics of the Jules Horowitz Reactor are presented. Safety criteria are explained. Finally, merits and disadvantages of UMo compared to the standard U{sub 3}Si{sub 2} fuel are discussed. (author)

  8. Neutrino Mixing Discriminates Geo-reactor Models

    CERN Document Server

    Dye, S T

    2009-01-01

    Geo-reactor models suggest the existence of natural nuclear reactors at different deep-earth locations with loosely defined output power. Reactor fission products undergo beta decay with the emission of electron antineutrinos, which routinely escape the earth. Neutrino mixing distorts the energy spectrum of the electron antineutrinos. Characteristics of the distorted spectrum observed at the earth's surface could specify the location of a geo-reactor, discriminating the models and facilitating more precise power measurement. The existence of a geo-reactor with known position could enable a precision measurement of the neutrino oscillation parameter delta-mass-squared.

  9. Reactor monitoring and safeguards using antineutrino detectors

    CERN Document Server

    Bowden, N S

    2008-01-01

    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.

  10. Reactor assessments of advanced bumpy torus configurations

    Energy Technology Data Exchange (ETDEWEB)

    Uckan, N.A.; Owen, L.W.; Spong, D.A.; Miller, R.L.; Ard, W.B.; Pipkins, J.F.; Schmitt, R.J.

    1983-01-01

    Recently, several configurational approaches and concept improvement schemes were introduced for enhancing the performance of the basic ELMO Bumpy Torus (EBT) concept and for improving its reactor potential. These configurations include planar racetrack and square geometries, Andreoletti coil systems, and bumpy torus-stellarator hybrids (which include twisted racetrack and helical axis stellarator-snakey torus). Preliminary evaluations of reactor implications of each of these configurations have been carried out based on magnetics (vacuum) calculations, transport and scaling relationships, and stability properties. Results indicate favorable reactor projections with a significant reduction in reactor physical size as compared to conventional EBT reactor designs carried out in the past.

  11. Detection of antineutrinos for reactor monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yeong Duk [Center for Underground Physics, Institute of Basic Science, Daejeon (Korea, Republic of)

    2016-04-15

    Reactor neutrinos have been detected in the past 50 years by various detectors for different purposes. Beginning in the 1980s, neutrino physicists have tried to use neutrinos to monitor reactors and develop an optimized detector for nuclear safeguards. Recently, motivated by neutrino oscillation physics, the technology and scale of reactor neutrino detection have progressed considerably. In this review, I will give an overview of the detection technology for reactor neutrinos, and describe the issues related to further improvements in optimized detectors for reactor monitoring.

  12. CFD Simulation on Ethylene Furnace Reactor Tubes

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Different mathematical models for ethylene furnace reactor tubes were reviewed. On the basis of these models a new mathematical simulation approach for reactor tubes based on computational fluid dynamics (CFD) technique was presented. This approach took the flow, heat transfer, mass transfer and thermal cracking reactions in the reactor tubes into consideration. The coupled reactor model was solved with the SIMPLE algorithm. Some detailed information about the flow field, temperature field and concentration distribution in the reactor tubes was obtained, revealing the basic characteristics of the hydrodynamic phenomena and reaction behavior in the reactor tubes. The CFD approach provides the necessary information for conclusive decisions regarding the production optimization, the design and improvement of reactor tubes, and the new techniques implementation.

  13. Advanced reactor physics methods for heterogeneous reactor cores

    Science.gov (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.

  14. Reactor pulse repeatability studies at the annular core research reactor

    Energy Technology Data Exchange (ETDEWEB)

    DePriest, K.R. [Applied Nuclear Technologies, Sandia National Laboratories, Mail Stop 1146, Post Office Box 5800, Albuquerque, NM 87185-1146 (United States); Trinh, T.Q. [Nuclear Facility Operations, Sandia National Laboratories, Mail Stop 0614, Post Office Box 5800, Albuquerque, NM 87185-1146 (United States); Luker, S. M. [Applied Nuclear Technologies, Sandia National Laboratories, Mail Stop 1146, Post Office Box 5800, Albuquerque, NM 87185-1146 (United States)

    2011-07-01

    The Annular Core Research Reactor (ACRR) at Sandia National Laboratories is a water-moderated pool-type reactor designed for testing many types of objects in the pulse and steady-state mode of operations. Personnel at Sandia began working to improve the repeatability of pulse operations for experimenters in the facility. The ACRR has a unique UO{sub 2}-BeO fuel that makes the task of producing repeatable pulses difficult with the current operating procedure. The ACRR produces a significant quantity of photoneutrons through the {sup 9}Be({gamma}, n){sup 8}Be reaction in the fuel elements. The photoneutrons are the result of the gammas produced during fission and in fission product decay, so their production is very much dependent on the reactor power history and changes throughout the day/week of experiments in the facility. Because the photoneutrons interfere with the delayed-critical measurements required for accurate pulse reactivity prediction, a new operating procedure was created. The photoneutron effects at delayed critical are minimized when using the modified procedure. In addition, the pulse element removal time is standardized for all pulse operations with the modified procedure, and this produces less variation in reactivity removal times. (authors)

  15. In-reactor performance of pressure tubes in CANDU reactors

    Science.gov (United States)

    Rodgers, D. K.; Coleman, C. E.; Griffiths, M.; Bickel, G. A.; Theaker, J. R.; Muir, I.; Bahurmuz, A. A.; Lawrence, S. St.; Resta Levi, M.

    2008-12-01

    The pressure tubes in CANDU reactors have been operating for times up to about 25 years. The in-reactor performance of Zr-2.5Nb pressure tubes has been evaluated by sampling and periodic inspection. This paper describes the behaviour and discusses the factors controlling the behaviour of these components in currently operating CANDU reactors. The mechanical properties (such as ultimate tensile strength, UTS, and fracture toughness), and delayed-hydride-cracking properties (crack growth rate Vc, and threshold stress intensity factor, KIH) change with irradiation; the former reach a limiting value at a fluence of Pressure tubes exhibit elongation and diametral expansion. The deformation behaviour is a function of operating conditions and material properties that vary from tube-to-tube and as a function of axial location. Semi-empirical predictive models have been developed to describe the deformation response of average tubes as a function of operating conditions. For corrosion and, more importantly deuterium pickup, semi-empirical predictive models have also been developed to represent the behaviour of an average tube. The effect of material variability on corrosion behaviour is less well defined compared with other properties. Improvements in manufacturing have increased fracture resistance by minimising trace elements, especially H and Cl, and reduced variability by tightening controls on forming parameters, especially hot-working temperatures.

  16. Borgerkrig fra Athen til Auschwitz

    DEFF Research Database (Denmark)

    Flohr, Mikkel

    2015-01-01

    The starting point of this article is the concept of civil war in Giorgio Agamben’s Homo Sacer-series. In spite of its relative obscurity, Agamben insists that it is the fundamental political structure, which has characterized all of western history since Ancient Greece. As such it constitutes a ...

  17. Athens, Kylon, and the Dipolieia

    Directory of Open Access Journals (Sweden)

    Dimitri Nakassis

    2011-08-01

    Full Text Available Shared elements, especially topographical and judicial, in the ritual and myth of the Dipolieia and the narrative of the murder of the Cylonian conspirators imply that the two accounts came to be assimilated in Athenian consciousness.

  18. Nineteenth Workshop Athens, GA, USA

    CERN Document Server

    Lewis, S P; Schöttler, H B; Computer Simulation Studies in Condensed-Matter Physics XIX

    2008-01-01

    This volume represents a "status report" emanating from presentations made during the 19th Annual Workshop on Computer Simulations Studies in Condensed Matter Physics at the Center for Simulational Physics at the University of Georgia in February, 2006. It provides a broad overview of the most recent advances in the field, spanning the range from equilibrium and non-equilibrium behavior in statistical physics to biological and soft condensed matter systems. Results on nanomagents and materials are included as are several descriptions of advances in methodology.

  19. HYDRAULICS, ATHENS COUNTY, OHIO, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Hydraulic data include spatial datasets and data tables necessary for documenting the hydrologic procedures for estimating flood discharges for a flood insurance...

  20. HYDROLOGY, ATHENS COUNTY, OHIO, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Hydrology data include spatial datasets and data tables necessary for documenting the hydrologic procedures for estimating flood discharges for a flood insurance...

  1. Fluidized bed coal combustion reactor

    Science.gov (United States)

    Moynihan, P. I.; Young, D. L. (Inventor)

    1981-01-01

    A fluidized bed coal reactor includes a combination nozzle-injector ash-removal unit formed by a grid of closely spaced open channels, each containing a worm screw conveyor, which function as continuous ash removal troughs. A pressurized air-coal mixture is introduced below the unit and is injected through the elongated nozzles formed by the spaces between the channels. The ash build-up in the troughs protects the worm screw conveyors as does the cooling action of the injected mixture. The ash layer and the pressure from the injectors support a fluidized flame combustion zone above the grid which heats water in boiler tubes disposed within and/or above the combustion zone and/or within the walls of the reactor.

  2. Nuclear reactor alignment plate configuration

    Energy Technology Data Exchange (ETDEWEB)

    Altman, David A; Forsyth, David R; Smith, Richard E; Singleton, Norman R

    2014-01-28

    An alignment plate that is attached to a core barrel of a pressurized water reactor and fits within slots within a top plate of a lower core shroud and upper core plate to maintain lateral alignment of the reactor internals. The alignment plate is connected to the core barrel through two vertically-spaced dowel pins that extend from the outside surface of the core barrel through a reinforcement pad and into corresponding holes in the alignment plate. Additionally, threaded fasteners are inserted around the perimeter of the reinforcement pad and into the alignment plate to further secure the alignment plate to the core barrel. A fillet weld also is deposited around the perimeter of the reinforcement pad. To accomodate thermal growth between the alignment plate and the core barrel, a gap is left above, below and at both sides of one of the dowel pins in the alignment plate holes through with the dowel pins pass.

  3. Transport simulation for EBT reactor

    Energy Technology Data Exchange (ETDEWEB)

    Uckan, T.; Uckan, N.A.; Jaeger, E.F.

    1983-08-01

    Transport simulation and modeling studies for the ELMO Bumpy Torus (EBT) reactor are carried out by using zero-dimensional (0-D) and one-and-one-half-dimensional (1 1/2-D) transport calculations. The time-dependent 0-D model is used for global analysis, whereas the 1 1/2-D radial transport code is used for accurate determination of density, temperature, and ambipolar potential profiles and of the role of these profiles in reactor plasma performance. Analysis with the 1 1/2-D transport code shows that profile effects near the outer edge of the hot electron ring lead to enhanced confinement by at least a factor of 2 to 5 beyond the simple scaling that is obtained from the global analysis. The radial profiles of core plasma density and temperatures (or core pressure) obtained from 1 1/2-D transport calculations are found to be similar to those theoretically required for stability.

  4. Gas-liquid autoxidation reactors

    Energy Technology Data Exchange (ETDEWEB)

    Morbidelli, M.; Paludetto, R.; Carra, S.

    1986-01-01

    A procedure for the simulation of autoxidation gas-liquid reactors has been developed based both on mathematical models and laboratory experiments. It has been shown that the complex radical chain mechanism of the autoxidation process can be simulated through two global parallel reactions, whose rates are obtained by assuming pseudo-steady-state concentration values for all the radical species involved. Using ethylbenzene autoxidation as a model reaction, an experimental analysis has been performed in order to estimate all the kinetic parameters of the model. The effect of the interaction between gas-liquid mass-transfer phenomena and the complex kinetic mechanism on the overall performance of an autoxidation reactor has been examined in detail within the framework of the liquid film model.

  5. Fast breeder reactor protection system

    Science.gov (United States)

    van Erp, J.B.

    1973-10-01

    Reactor protection is provided for a liquid-metal-fast breeder reactor core by measuring the coolant outflow temperature from each of the subassemblies of the core. The outputs of the temperature sensors from a subassembly region of the core containing a plurality of subassemblies are combined in a logic circuit which develops a scram alarm if a predetermined number of the sensors indicate an over temperature condition. The coolant outflow from a single subassembly can be mixed with the coolant outflow from adjacent subassemblies prior to the temperature sensing to increase the sensitivity of the protection system to a single subassembly failure. Coherence between the sensors can be required to discriminate against noise signals. (Official Gazette)

  6. 27 November 2013 - Greek Deputy Minister of Health Z. Makri with Governor of Thessaly K. Agorastos visiting the LHC superconducting magnet test hall with Senior Scientists D. Delikaris, E. Hatziangeli and E. Tsesmelis. E. Gazis, ATLAS Collaboration, National Technical University of Athens also present.

    CERN Document Server

    Anna Pantelia

    2013-01-01

    27 November 2013 - Greek Deputy Minister of Health Z. Makri with Governor of Thessaly K. Agorastos visiting the LHC superconducting magnet test hall with Senior Scientists D. Delikaris, E. Hatziangeli and E. Tsesmelis. E. Gazis, ATLAS Collaboration, National Technical University of Athens also present.

  7. Reactor vessel lower head integrity

    Energy Technology Data Exchange (ETDEWEB)

    Rubin, A.M.

    1997-02-01

    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.

  8. The ARIES tokamak reactor study

    Energy Technology Data Exchange (ETDEWEB)

    1989-10-01

    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.

  9. Actinide transmutation in nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Bultman, J.H.

    1995-01-17

    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).

  10. Assessment of the thorium fuel cycle in power reactors

    Energy Technology Data Exchange (ETDEWEB)

    Kasten, P.R.; Homan, F.J.; Allen, E.J.

    1977-01-01

    A study was conducted at Oak Ridge National Laboratory to evaluate the role of thorium fuel cycles in power reactors. Three thermal reactor systems were considered: Light Water Reactors (LWRs); High-Temperature Gas-Cooled Reactors (HTGRs); and Heavy Water Reactors (HWRs) of the Canadian Deuterium Uranium Reactor (CANDU) type; most of the effort was on these systems. A summary comparing thorium and uranium fuel cycles in Fast Breeder Reactors (FBRs) was also compiled.

  11. Investigation of molten salt fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kubota, Kenichi; Konomura, Mamoru [Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan)

    2002-05-01

    On survey research for practicability strategy of fast reactor (FR) (phase 1), to extract future practicability image candidates of FR from wide options, in addition to their survey and investigation objects of not only solid fuel reactors of conventional research object but also molten salt reactor as a flowing fuel reactor, investigation on concept of molten salt FR plant was carried out. As a part of the first step of the survey research for practicability strategy, a basic concept on plant centered at nuclear reactor facility using chloride molten salt reactor capable of carrying out U-Pu cycle was examined, to perform a base construction to evaluate economical potential for a practical FBR. As a result, a result could be obtained that because of inferior fuel inventory and heat transmission to those in Na cooling reactor in present knowledge, mass of reactor vessel and intermediate heat exchanger were to widely increased to expect reduction of power generation unit price even on considering cheapness of its fuel cycle cost. Therefore, at present step further investigation on concept design of the chloride molten salt reactor plant system is too early in time, and it is at a condition where basic and elementary researches aiming at upgrading of economical efficiency such as wide reduction of fuel inventory, a measure expectable for remarkable rationalization effect of reprocessing system integrating a reactor to a processing facility, and so on. (G.K.)

  12. Multi-wavelength Raman lidar, sunphotometric and aircraft measurements in combination with inversion models for the estimation of the aerosol optical and physico-chemical properties over Athens, Greece

    Directory of Open Access Journals (Sweden)

    R. E. Mamouri

    2012-01-01

    Full Text Available A novel procedure has been developed to retrieve, simultaneously, the optical, microphysical and chemical properties of tropospheric aerosols with a multi-wavelength Raman lidar system in the troposphere over an urban site (Athens, Greece: 37.9° N, 23.6° E, 200 m a.s.l. using data obtained during the European Space Agency (ESA THERMOPOLIS project which took place between 15–31 July 2009 over the Greater Athens Area (GAA. We selected to apply our procedure for a case study of intense aerosol layers occurred on 20–21 July 2009. The National Technical University of Athens (NTUA EOLE 6-wavelength Raman lidar system has been used to provide the vertical profiles of the optical properties of aerosols (extinction and backscatter coefficients, lidar ratio and the water vapor mixing ratio. An inversion algorithm was used to derive the mean aerosol microphysical properties (mean effective radius – reff, single-scattering albedo (ω and mean complex refractive index (m at selected heights in the 2–3 km height region. We found that reff was 0.3–0.4 μm, ω at 532 nm ranged from 0.63 to 0.88 and m ranged from 1.45 + 0.015i to 1.56 + 0.05i, in good accordance with in situ aircraft measurements. The final data set of the aerosol microphysical properties along with the water vapor and temperature profiles were incorporated into the ISORROPIA model to infer an in situ aerosol composition consistent with the retrieved m and ω values. The retrieved aerosol chemical composition in the 2–3 km height region gave a variable range of sulfate (0–60% and organic carbon (OC content (0–50%, although the OC content increased (up to 50% and the sulfate content dropped (up to 30% around 3 km height; in connection with the retrieved low ω value (0.63, indicates the presence of absorbing biomass burning smoke mixed with urban haze. Finally, the retrieved aerosol microphysical properties

  13. 雅典举办两届现代奥运会历史背景及全球性贡献考略%The Historical Background of Two Modern Olympic Games Held in Athens and Their Global Contributions

    Institute of Scientific and Technical Information of China (English)

    马岳良

    2012-01-01

    从19世纪末到21世纪初,雅典举办了两届现代奥运会,这是奥林匹克运动跨世纪发展和人类文明急速演进的最好见证。本文通过历史追溯认为,首届现代奥运会是在欧洲工业化时代爆发的文艺复兴、宗教改革和启蒙运动推动近代体育的发展,从而使以人文主义为主旨的奥林匹克运动得以复兴;28届雅典奥运会则是在经济全球化、文化多元化趋势加快得以复兴,人类高扬“和平与发展”主题的大背景下复归的。雅典举办两届现代奥运会对人类的文明与发展具有历史性和开创性贡献。%From the 19th century to the 21th century, twice modem Olympic Games were held in Athens which is the best witness of trans - century development of the Olympic movement and the rapid evolution of human civiliza-tion. This paper holds the view that with the retrospection to the history, the first modem Olympic Games is the renaissance during the outbreak of the industrial age in Europe, the religious reform and the development that the enlightenment promotes modem sports, so that the Olympic Movement as the mayor idea of humanism gets revita - lized; and that the 28th Athens Olympic Games was held in the background that the economic globalization and the tendency of cultural diversity speed up, and that humans uplift the theme of "peace and development" ; and that the two modem Olympic Games held in Athens have made historical and pioneering contributions to the human civilization and development.

  14. Multi-wavelength Raman lidar, sun photometric and aircraft measurements in combination with inversion models for the estimation of the aerosol optical and physico-chemical properties over Athens, Greece

    Science.gov (United States)

    Mamouri, R. E.; Papayannis, A.; Amiridis, V.; Müller, D.; Kokkalis, P.; Rapsomanikis, S.; Karageorgos, E. T.; Tsaknakis, G.; Nenes, A.; Kazadzis, S.; Remoundaki, E.

    2012-07-01

    A novel procedure has been developed to retrieve, simultaneously, the optical, microphysical and chemical properties of tropospheric aerosols with a multi-wavelength Raman lidar system in the troposphere over an urban site (Athens, Greece: 37.9° N, 23.6° E, 200 m a.s.l.) using data obtained during the European Space Agency (ESA) THERMOPOLIS project, which took place between 15-31 July 2009 over the Greater Athens Area (GAA). We selected to apply our procedure for a case study of intense aerosol layers that occurred on 20-21 July 2009. The National Technical University of Athens (NTUA) EOLE 6-wavelength Raman lidar system has been used to provide the vertical profiles of the optical properties of aerosols (extinction and backscatter coefficients, lidar ratio) and the water vapor mixing ratio. An inversion algorithm was used to derive the mean aerosol microphysical properties (mean effective radius (reff), single-scattering albedo ω) and mean complex refractive index (m)) at selected heights in the 2-3 km height region. We found that reff was 0.14-0.4 (±0.14) μm, ω was 0.63-0.88 (±0.08) (at 532 nm) and m ranged from 1.44 (±0.10) + 0.01 (±0.01)i to 1.55 (±0.12) + 0.06 (±0.02)i, in good agreement (only for the reff values) with in situ aircraft measurements. The water vapor and temperature profiles were incorporated into the ISORROPIA II model to propose a possible in situ aerosol composition consistent with the retrieved m and ω values. The retrieved aerosol chemical composition in the 2-3 km height region gave a variable range of sulfate (0-60%) and organic carbon (OC) content (0-50%), although the OC content increased (up to 50%) and the sulfate content dropped (up to 30%) around 3 km height; the retrieved low ω value (0.63), indicates the presence of absorbing biomass burning smoke mixed with urban haze. Finally, the retrieved aerosol microphysical properties were compared with column-integrated sun photometer CIMEL data.

  15. Early HIV diagnosis through use of rapid diagnosis test (RDT in the community and direct link to HIV care: a pilot project for vulnerable populations in Athens, Greece

    Directory of Open Access Journals (Sweden)

    Eleni Kakalou

    2014-11-01

    Full Text Available Introduction: An increase in the incidence of HIV new infections among intravenous drug users (IDUs by 1500%, was noted in the center of Athens in 2011. Increasing problematic drug use, homelessness, health cuts amidst the economic crisis, have contributed to the epidemic. New cases doubled within a year, challenging the HIV care delivery system (1. Materials and Methods: A pilot project funded by the National Strategic Reference Framework (NSRF 2007–2013 of the European Union (EU, was launched from August 2012 to March 2014. It was a partnership between the HIV Clinic of Evangelismos Hospital and the NGO PRAKSIS. The project is aimed at offering early diagnosis and comprehensive care to hard to reach populations. RDT diagnosis through mobile units, direct linkage to care, elimination of waiting times, flexibility, psychosocial support and link to harm reduction services for active IDUs were offered to the beneficiaries. Results: A total of 117 people enrolled in the program following HIV RDT offered by mobile units of the NGO PRAKSIS in community sites. Sixty-eight percent were IDUs, 12% were men who have sex with men (MSM and 19.5% were heterosexuals. Men were 74.3% and women were 25.6%. Country born patients were 43.5% and non-country born patients were 56.4%. Nine people were HIV negative but needed post-exposure prophylaxis (PEP, treatment for Hepatitis C and one test was false positive. Two deaths occurred and six people were deported. Of the remaining 100 patients, 84 enrolled in the care program. Of those 77% (65/84 remain in care for three months after the end of the project. Care retention was 73.5% (39/53 for IDUs, 91% (10/11 for MSM, 80% (16/20 for heterosexuals, 73% (25/35 for country born and 82% (40/49 for non-country born individuals. Among those that remain in care, 77.7% (42/54 with 90% have undetectable viral load. Mean value of CD4 cells at enrollment was 298 cells/mm3. At follow up, three months after the end of the

  16. Molten-Salt Depleted-Uranium Reactor

    CERN Document Server

    Dong, Bao-Guo; Gu, Ji-Yuan

    2015-01-01

    The supercritical, reactor core melting and nuclear fuel leaking accidents have troubled fission reactors for decades, and greatly limit their extensive applications. Now these troubles are still open. Here we first show a possible perfect reactor, Molten-Salt Depleted-Uranium Reactor which is no above accident trouble. We found this reactor could be realized in practical applications in terms of all of the scientific principle, principle of operation, technology, and engineering. Our results demonstrate how these reactors can possess and realize extraordinary excellent characteristics, no prompt critical, long-term safe and stable operation with negative feedback, closed uranium-plutonium cycle chain within the vessel, normal operation only with depleted-uranium, and depleted-uranium high burnup in reality, to realize with fission nuclear energy sufficiently satisfying humanity long-term energy resource needs, as well as thoroughly solve the challenges of nuclear criticality safety, uranium resource insuffic...

  17. 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: jbisang@fiq.unl.edu.ar [Programa de Electroquimica Aplicada e Ingenieria Electroquimica (PRELINE), Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santiago del Estero 2829, S3000AOM Santa Fe (Argentina)

    2011-07-01

    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.

  18. Sulfide toxicity kinetics of a uasb reactor

    Directory of Open Access Journals (Sweden)

    D. R. Paula Jr.

    2009-12-01

    Full Text Available The effect of sulfide toxicity on kinetic parameters of anaerobic organic matter removal in a UASB (up-flow anaerobic sludge blanket reactor is presented. Two lab-scale UASB reactors (10.5 L were operated continuously during 12 months. The reactors were fed with synthetic wastes prepared daily using glucose, ammonium acetate, methanol and nutrient solution. One of the reactors also received increasing concentrations of sodium sulfide. For both reactors, the flow rate of 16 L.d-1 was held constant throughout the experiment, corresponding to a hydraulic retention time of 15.6 hours. The classic model for non-competitive sulfide inhibition was applied to the experimental data for determining the overall kinetic parameter of specific substrate utilization (q and the sulfide inhibition coefficient (Ki. The application of the kinetic parameters determined allows prediction of methanogenesis inhibition and thus the adoption of operating parameters to minimize sulfide toxicity in UASB reactors.

  19. Introduction to the neutron kinetics of nuclear power reactors

    CERN Document Server

    Tyror, J G; Grant, P J

    2013-01-01

    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

  20. Microstructured reactors for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Aartun, Ingrid

    2005-07-01

    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

  1. Plasma spark discharge reactor and durable electrode

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young I.; Cho, Daniel J.; Fridman, Alexander; Kim, Hyoungsup

    2017-01-10

    A plasma spark discharge reactor for treating water. The plasma spark discharge reactor comprises a HV electrode with a head and ground electrode that surrounds at least a portion of the HV electrode. A passage for gas may pass through the reactor to a location proximate to the head to provide controlled formation of gas bubbles in order to facilitate the plasma spark discharge in a liquid environment.

  2. Experimental Breeder Reactor I Preservation Plan

    Energy Technology Data Exchange (ETDEWEB)

    Julie Braun

    2006-10-01

    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.

  3. Reactor Bolshoi Moshchnosti Kalani; Reacteurs RBMK

    Energy Technology Data Exchange (ETDEWEB)

    Bastien, D. [Conservatoire National des Arts et Metiers (CNAM), 75 - Paris (France)

    2000-01-01

    The Reactor Bolshoi Molshchnosti Kalani (RBMK) are pressure tubes reactor, boiling light water cooled. Exported since 1990 from the ex-USSR, they are today in three independent countries: Russian, Ukraine and Lithuania. Since this date, data exchange with the occident allowed the better knowledge of this reactor type. The design, the technical description (core, fuel, primary system), the safety and the improvement since Chernobyl are detailed. (A.L.B.)

  4. NASA Reactor Facility Hazards Summary. Volume 1

    Science.gov (United States)

    1959-01-01

    The Lewis Research Center of the National Aeronautics and Space Administration proposes to build a nuclear research reactor which will be located in the Plum Brook Ordnance Works near Sandusky, Ohio. The purpose of this report is to inform the Advisory Committee on Reactor Safeguards of the U. S. Atomic Energy Commission in regard to the design Lq of the reactor facility, the characteristics of the site, and the hazards of operation at this location. The purpose of this research reactor is to make pumped loop studies of aircraft reactor fuel elements and other reactor components, radiation effects studies on aircraft reactor materials and equipment, shielding studies, and nuclear and solid state physics experiments. The reactor is light water cooled and moderated of the MTR-type with a primary beryllium reflector and a secondary water reflector. The core initially will be a 3 by 9 array of MTR-type fuel elements and is designed for operation up to a power of 60 megawatts. The reactor facility is described in general terms. This is followed by a discussion of the nuclear characteristics and performance of the reactor. Then details of the reactor control system are discussed. A summary of the site characteristics is then presented followed by a discussion of the larger type of experiments which may eventually be operated in this facility. The considerations for normal operation are concluded with a proposed method of handling fuel elements and radioactive wastes. The potential hazards involved with failures or malfunctions of this facility are considered in some detail. These are examined first from the standpoint of preventing them or minimizing their effects and second from the standpoint of what effect they might have on the reactor facility staff and the surrounding population. The most essential feature of the design for location at the proposed site is containment of the maximum credible accident.

  5. Heat for industry from nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Kikoin, I.K.; Novikov, V.M.

    Two factors which incline nations toward the use of heat from nuclear reactors for industrial use are: 1) exhaustion of cheap fossil fuel resources, and 2) ecological problems associated both with extraction of fossil fuel from the earth and with its combustion. In addition to the usual problems that beset nuclear reactors, special problems associated with using heat from nuclear reactors in various industries are explored.

  6. D-D tokamak reactor studies

    Energy Technology Data Exchange (ETDEWEB)

    Evans, K.E. Jr.; Baker, C.C.; Brooks, J.N.; Ehst, D.A.; Finn, P.A.; Jung, J.; Mattas, R.F.; Misra, B.; Smith, D.L.; Stevens, H.C.

    1980-11-01

    A tokamak D-D reactor design, utilizing the advantages of a deuterium-fueled reactor but with parameters not unnecessarily extended from existing D-T designs, is presented. Studies leading to the choice of a design and initial studies of the design are described. The studies are in the areas of plasma engineering, first-wall/blanket/shield design, magnet design, and tritium/fuel/vacuum requirements. Conclusions concerning D-D tokamak reactors are stated.

  7. Compendium in astronomy a volume dedicated to professor John Xanthakis on the occasion of completing twenty-five years of scientific activities as fellow of the National Academy of Athens

    CERN Document Server

    Theocaris, Pericles; Mavridis, L

    1982-01-01

    When we first approached some colleagues allover the world to sound them about a volume dedicated to Professor John Xanthakis on the occasion of completing twenty-five years of scientific activities as fellow of the National Academy of Athens, any possible doubts as to the feasibility of the project were quickly dispelled by their warm and encouraging response. In a short time 50 authors from 15 countries, coming from a wide range of Professor Xanthakis' immediate colleagues, pupils and friends joined to produce the 36 contributions included in this volume. Some of those who where originally approached found themselves un­ able to contribute, because of the time-limit necessarily imposed. Happi­ ly, they were only few in number, and we should like to record our grat­ itude to them for their good wishes for the success of the venture. Their warm words were among the many sources of inspiring encouragement extended to us.

  8. A Methodology to Validate the InSAR Derived Displacement Field of the September 7th, 1999 Athens Earthquake Using Terrestrial Surveying. Improvement of the Assessed Deformation Field by Interferometric Stacking

    Science.gov (United States)

    Kotsis, Ioannis; Kontoes, Charalabos; Paradissis, Dimitrios; Karamitsos, Spyros; Elias, Panagiotis; Papoutsis, Ioannis

    2008-01-01

    The primary objective of this paper is the evaluation of the InSAR derived displacement field caused by the 07/09/1999 Athens earthquake, using as reference an external data source provided by terrestrial surveying along the Mornos river open aqueduct. To accomplish this, a processing chain to render comparable the leveling measurements and the interferometric derived measurements has been developed. The distinct steps proposed include a solution for reducing the orbital and atmospheric interferometric fringes and an innovative method to compute the actual InSAR estimated vertical ground subsidence, for direct comparison with the leveling data. Results indicate that the modeled deformation derived from a series of stacked interferograms, falls entirely within the confidence interval assessed for the terrestrial surveying data. PMID:27879926

  9. A Methodology to Validate the InSAR Derived Displacement Field of the September 7th, 1999 Athens Earthquake Using Terrestrial Surveying. Improvement of the Assessed Deformation Field by Interferometric Stacking

    Directory of Open Access Journals (Sweden)

    Ioannis Papoutsis

    2008-06-01

    Full Text Available The primary objective of this paper is the evaluation of the InSAR derived displacement field caused by the 07/09/1999 Athens earthquake, using as reference an external data source provided by terrestrial surveying along the Mornos river open aqueduct. To accomplish this, a processing chain to render comparable the leveling measurements and the interferometric derived measurements has been developed. The distinct steps proposed include a solution for reducing the orbital and atmospheric interferometric fringes and an innovative method to compute the actual InSAR estimated vertical ground subsidence, for direct comparison with the leveling data. Results indicate that the modeled deformation derived from a series of stacked interferograms, falls entirely within the confidence interval assessed for the terrestrial surveying data.

  10. 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)

    2014-09-01

    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.

  11. High Performance Photocatalytic Oxidation Reactor System Project

    Data.gov (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...

  12. Savannah River Site reactor safety assessment. Draft

    Energy Technology Data Exchange (ETDEWEB)

    Woody, N.D.; Brandyberry, M.D. [eds.] [Westinghouse Savannah River Co., Aiken, SC (United States); Baker, W.H.; Brandyberry, M.D.; Kearnaghan, D.P.; O`Kula, K.R.; Woody, N.D. [Westinghouse Savannah River Co., Aiken, SC (United States); Amos, C.N.; Weingardt, J.J. [Science Applications International Corp., San Diego, CA (United States)

    1991-02-28

    This report gives the results of a Savannah River Site (SRS) Production Reactor risk assessment. Measures of adverse consequences to health and safety resulting from representations of severe accidents in SRS reactors are presented. In addition, the report gives a summary of the methods employed to represent these accidents and to assess the resultant consequences. The report is issued to provide timely information to the US Department of Energy (DOE) on the risk of operation of SRS reactors, for insights into severe accident phenomena that contribute to this risk, and in support of improved bases for other Site programs in Heavy Water Reactor safety.

  13. History of fast reactor fuel development

    Energy Technology Data Exchange (ETDEWEB)

    Kittel, J.H.; Frost, B.R.T. (Argonne National Lab., IL (United States)); Mustelier, J.P. (COGEMA, Velizy-Villacoublay (France))

    1992-01-01

    Most of the first generation of fast reactors that were operated at significant power levels employed solid metal fuels. They were constructed in the United States and United Kingdom in the 1950s and included Experimental Breeder Reactor (EBR)-I and -II operated by Argonne National Laboratory, United States, the Enrico Fermi Reactor operated by the Atomic Power Development Associates, United States and DFR operated by the U.K. Atomic Energy Authority (UKAEA). Their paper tracer pre-development of fast reactor fuel from these early days through the 1980s including ceramic fuels.

  14. 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)

    1995-07-01

    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.

  15. Supercritical-pressure light water cooled reactors

    CERN Document Server

    Oka, Yoshiaki

    2014-01-01

    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

  16. Sandia National Laboratories Medical Isotope Reactor concept.

    Energy Technology Data Exchange (ETDEWEB)

    Coats, Richard Lee; Dahl, James J.; Parma, Edward J., Jr.

    2010-04-01

    This report describes the Sandia National Laboratories Medical Isotope Reactor and hot cell facility concepts. The reactor proposed is designed to be capable of producing 100% of the U.S. demand for the medical isotope {sup 99}Mo. The concept is novel in that the fuel for the reactor and the targets for the {sup 99}Mo production are the same. There is no driver core required. The fuel pins that are in the reactor core are processed on a 7 to 21 day irradiation cycle. The fuel is low enriched uranium oxide enriched to less than 20% {sup 235}U. The fuel pins are approximately 1 cm in diameter and 30 to 40 cm in height, clad with Zircaloy (zirconium alloy). Approximately 90 to 150 fuel pins are arranged in the core in a water pool {approx}30 ft deep. The reactor power level is 1 to 2 MW. The reactor concept is a simple design that is passively safe and maintains negative reactivity coefficients. The total radionuclide inventory in the reactor core is minimized since the fuel/target pins are removed and processed after 7 to 21 days. The fuel fabrication, reactor design and operation, and {sup 99}Mo production processing use well-developed technologies that minimize the technological and licensing risks. There are no impediments that prevent this type of reactor, along with its collocated hot cell facility, from being designed, fabricated, and licensed today.

  17. NCSU reactor sharing program. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Perez, P.B.

    1997-01-10

    The Nuclear Reactor Program at North Carolina State University provides the PULSTAR Research Reactor and associated facilities to eligible institutions with support, in part, from the Department of Energy Reactor Sharing Program. Participation in the NCSU Reactor Sharing Program continues to increase steadily with visitors ranging from advance high school physics and chemistry students to Ph.D. level research from neighboring universities. This report is the Final Technical Report for the DOE award reference number DE-FG05-95NE38136 which covers the period September 30, 1995 through September 30, 1996.

  18. Molecular ecology of anaerobic reactor systems

    DEFF Research Database (Denmark)

    Hofman-Bang, H. Jacob Peider; Zheng, D.; Westermann, Peter;

    2003-01-01

    Anaerobic reactor systems are essential for the treatment of solid and liquid wastes and constitute a core facility in many waste treatment plants. Although much is known about the basic metabolism in different types of anaerobic reactors, little is known about the microbes responsible...... to the abundance of each microbe in anaerobic reactor systems by rRNA probing. This chapter focuses on various molecular techniques employed and problems encountered when elucidating the microbial ecology of anaerobic reactor systems. Methods such as quantitative dot blot/fluorescence in-situ probing using various...

  19. Advances in light water reactor technologies

    CERN Document Server

    Saito, Takehiko; Ishiwatari, Yuki; Oka, Yoshiaki

    2010-01-01

    ""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

  20. Nanostructured Catalytic Reactors for Air Purification Project

    Data.gov (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...

  1. 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)

    1999-03-01

    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.

  2. Sodium fast reactors with closed fuel cycle

    CERN Document Server

    Raj, Baldev; Vasudeva Rao, PR 0

    2015-01-01

    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

  3. Autonomous Control of Space Nuclear Reactors Project

    Data.gov (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....

  4. Neutron imaging on the VR-1 reactor

    Science.gov (United States)

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

    2016-09-01

    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. Microchannel Methanation Reactors Using Nanofabricated Catalysts Project

    Data.gov (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...

  6. Nanostructured Catalytic Reactors for Air Purification Project

    Data.gov (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...

  7. Continuous steroid biotransformations in microchannel reactors.

    Science.gov (United States)

    Marques, Marco P C; Fernandes, Pedro; Cabral, Joaquim M S; Znidaršič-Plazl, Polona; Plazl, Igor

    2012-01-15

    The use of microchannel reactor based technologies within the scope of bioprocesses as process intensification and production platforms is gaining momentum. Such trend can be ascribed a particular set of characteristics of microchannel reactors, namely the enhanced mass and heat transfer, combined with easier handling and smaller volumes required, as compared to traditional reactors. In the present work, a continuous production process of 4-cholesten-3-one by the enzymatic oxidation of cholesterol without the formation of any by-product was assessed. The production was carried out within Y-shaped microchannel reactors in an aqueous-organic two-phase system. Substrate was delivered from the organic phase to aqueous phase containing cholesterol oxidase and the product formed partitions back to the organic phase. The aqueous phase was then forced through a plug-flow reactor, containing immobilized catalase. This step aimed at the reduction of hydrogen peroxide formed as a by-product during cholesterol oxidation, to avoid cholesterol oxidase deactivation due to said by-product. This setup was compared with traditional reactors and modes of operation. The results showed that microchannel reactor geometry outperformed traditional stirred tank and plug-flow reactors reaching similar conversion yields at reduced residence time. Coupling the plug-flow reactor containing catalase enabled aqueous phase reuse with maintenance of 30% catalytic activity of cholesterol oxidase while eliminating hydrogen peroxide. A final production of 36 m of cholestenone was reached after 300 hours of operation.

  8. Vertical Profiles of Aerosol Optical and Microphysical Properties During a Rare Case of Long-range Transport of Mixed Biomass Burning-polluted Dust Aerosols from the Russian Federation-kazakhstan to Athens, Greece

    Directory of Open Access Journals (Sweden)

    Papayannis Alexandros

    2016-01-01

    Full Text Available Multi-wavelength aerosol Raman lidar measurements with elastic depolarization at 532 nm were combined with sun photometry during the HYGRA-CD campaign over Athens, Greece, on May-June 2014. We retrieved the aerosol optical [3 aerosol backscatter profiles (baer at 355-532-1064 nm, 2 aerosol extinction (aaer profiles at 355-532 nm and the aerosol linear depolarization ratio (δ at 532 nm] and microphysical properties [effective radius (reff, complex refractive index (m, single scattering albedo (ω]. We present a case study of a long distance transport (~3.500-4.000 km of biomass burning particles mixed with dust from the Russian Federation-Kazakhstan regions arriving over Athens on 21-23 May 2014 (1.7-3.5 km height. On 23 May, between 2-2.75 km we measured mean lidar ratios (LR of 35 sr (355 nm and 42 sr (532 nm, while the mean Ångström exponent (AE aerosol backscatter-related values (355nm/532nm and 532nm/1064nm were 2.05 and 1.22, respectively; the mean value of δ at 532 nm was measured to be 9%. For that day the retrieved mean aerosol microphysical properties at 2-2.75 km height were: reff=0.26 μm (fine mode, reff=2.15 μm (coarse mode, m=1.36+0.00024i, ω=0.999 (355 nm, fine mode, ω=0.992(355 nm, coarse mode, ω=0.997 (532 nm, fine mode, and ω=0.980 (532 nm, coarse mode.

  9. Reactors for nuclear electric propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Buden, D.; Angelo, J.A. Jr.

    1981-01-01

    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.

  10. Biodegradation of MTBE in reactors

    DEFF Research Database (Denmark)

    Waul, Christopher Kevin

    2007-01-01

    The fuel oxygenate methyl tert-butyl ether (MTBE) was first introduced in the 1970’s to improve gasoline combustion efficiency and reduce emission of harmful gases. However, it has caused groundwater contamination in Denmark and in many locations worldwide through accidental releases from leaking...... such as ammonium or benzene, toluene, ethyl benzene and xylene (BTEX) oxidizers, which can be present together in a single system. The competition resulted in reduced and/or delayed degradation of MTBE when there were limitations of oxygen or space in the reactor. The fraction of biologically active (BA) MTBE...

  11. Coupled reactor kinetics and heat transfer model for heat pipe cooled reactors

    Science.gov (United States)

    Wright, Steven A.; Houts, Michael

    2001-02-01

    Heat pipes are often proposed as cooling system components for small fission reactors. SAFE-300 and STAR-C are two reactor concepts that use heat pipes as an integral part of the cooling system. Heat pipes have been used in reactors to cool components within radiation tests (Deverall, 1973); however, no reactor has been built or tested that uses heat pipes solely as the primary cooling system. Heat pipe cooled reactors will likely require the development of a test reactor to determine the main differences in operational behavior from forced cooled reactors. The purpose of this paper is to describe the results of a systems code capable of modeling the coupling between the reactor kinetics and heat pipe controlled heat transport. Heat transport in heat pipe reactors is complex and highly system dependent. Nevertheless, in general terms it relies on heat flowing from the fuel pins through the heat pipe, to the heat exchanger, and then ultimately into the power conversion system and heat sink. A system model is described that is capable of modeling coupled reactor kinetics phenomena, heat transfer dynamics within the fuel pins, and the transient behavior of heat pipes (including the melting of the working fluid). This paper focuses primarily on the coupling effects caused by reactor feedback and compares the observations with forced cooled reactors. A number of reactor startup transients have been modeled, and issues such as power peaking, and power-to-flow mismatches, and loading transients were examined, including the possibility of heat flow from the heat exchanger back into the reactor. This system model is envisioned as a tool to be used for screening various heat pipe cooled reactor concepts, for designing and developing test facility requirements, for use in safety evaluations, and for developing test criteria for in-pile and out-of-pile test facilities. .

  12. Compound cryopump for fusion reactors

    CERN Document Server

    Kovari, M; Shephard, T

    2013-01-01

    We reconsider an old idea: a three-stage compound cryopump for use in fusion reactors such as DEMO. The helium "ash" is adsorbed on a 4.5 K charcoal-coated surface, while deuterium and tritium are adsorbed at 15-22 K on a second charcoal-coated surface. The helium is released by raising the first surface to ~30 K. In a separate regeneration step, deuterium and tritium are released at ~110 K. In this way, the helium can be pre-separated from other species. In the simplest design, all three stages are in the same vessel, with a single valve to close the pump off from the tokamak during regeneration. In an alternative design, the three stages are in separate vessels, connected by valves, allowing the stages to regenerate without interfering with each other. The inclusion of the intermediate stage would not affect the overall pumping speed significantly. The downstream exhaust processing system could be scaled down, as much of the deuterium and tritium could be returned directly to the reactor. This could reduce ...

  13. K-East and K-West Reactors

    Data.gov (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...

  14. 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)

    2003-07-01

    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)

  15. Annual report on JEN-1 reactor; Informe periodico del Reactor JEN-1 correspondiente al ano 1971

    Energy Technology Data Exchange (ETDEWEB)

    Montes, J.

    1972-07-01

    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)

  16. Selective purge for hydrogenation reactor recycle loop

    Science.gov (United States)

    Baker, Richard W.; Lokhandwala, Kaaeid A.

    2001-01-01

    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.

  17. Radiochemical problems of fusion reactors. 1. Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Crespi, M.B.A.

    1984-02-01

    A list of fusion reactor candidate materials is given, for use in connection with blanket structure, breeding, moderation, neutron multiplication, cooling, magnetic field generation, electrical insulation and radiation shielding. The phenomena being studied for each group of materials are indicated. Suitable irradiation test facilities are discussed under the headings (1) accelerator-based neutron sources, (2) fission reactors, and (3) ion accelerators.

  18. Advanced tokamak concepts and reactor designs

    NARCIS (Netherlands)

    Oomens, A. A. M.

    2000-01-01

    From a discussion of fusion reactor designs based on today's well-established experience gained in the operation of large tokamaks, it is concluded that such reactors are economically not attractive. The physics involved in the various options for concept improvement is described, some examples

  19. Startup of an industrial adiabatic tubular reactor

    NARCIS (Netherlands)

    Verwijs, J.W.; Berg, van den H.; Westerterp, K.R.

    1992-01-01

    The dynamic behaviour of an adiabatic tubular plant reactor during the startup is demonstrated, together with the impact of a feed-pump failure of one of the reactants. A dynamic model of the reactor system is presented, and the system response is calculated as a function of experimentally-determine

  20. Rotor for a pyrolysis centrifuge reactor

    DEFF Research Database (Denmark)

    2015-01-01

    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....

  1. Helix reactor: great potential for flow chemistry

    NARCIS (Netherlands)

    Geerdink, P.; Runstraat, A. van den; Roelands, C.P.M.; Goetheer, E.L.V.

    2009-01-01

    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

  2. The Design of a Nuclear Reactor

    Indian Academy of Sciences (India)

    2016-09-01

    The aim of this largely pedagogical article is toemploy pre-college physics to arrive at an understanding of a system as complex as a nuclear reactor. We focus on three key issues: the fuelpin, the moderator, and lastly the dimensions ofthe nuclear reactor.

  3. Design of an organic simplified nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Shirvan, Koroush [Dept. of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge (United States); Forrest, Eric [Primary Standards Laboratory, Sandia National Laboratories, Albuquerque (United States)

    2016-08-15

    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.

  4. Technical features of the MR reactor decommissioning

    Directory of Open Access Journals (Sweden)

    Craig David

    2008-01-01

    Full Text Available This paper presents a preliminary technical design for the dismantling of the MR reactor. The goal of the design is the removal of reactor components allowing the re-use of the building for a different nuclear related purpose. The sequence of segmentation procedures is established. Considerations on the size reduction and tooling are presented.

  5. The First Reactor, 40th Anniversary (rev.)

    Energy Technology Data Exchange (ETDEWEB)

    Allardice, Corbin; Trapnell, Edward R; Fermi, Enrico; Fermi, Laura; Williams, Robert C

    1982-12-01

    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.

  6. MODERATOR ELEMENTS FOR UNIFORM POWER NUCLEAR REACTOR

    Science.gov (United States)

    Balent, R.

    1963-03-12

    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)

  7. Parametric sensitivity and runaway in tubular reactors

    Energy Technology Data Exchange (ETDEWEB)

    Morbidelli, M.; Varma, A.

    1982-09-01

    Parametric sensitivity of tubular reactors is analyzed to provide critical values of the heat of reaction and heat transfer parameters defining runaway and stable operations for all positive-order exothermic reactions with finite activation energies, and for all reactor inlet temperatures. Evaluation of the critical values does not involve any trial and error.

  8. Microbial degradation of MTBE in reactors

    DEFF Research Database (Denmark)

    Waul, Christopher Kevin; Arvin, Erik; Schmidt, Jens Ejbye

    2007-01-01

    , 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...

  9. Design of an Organic Simplified Nuclear Reactor

    Directory of Open Access Journals (Sweden)

    Koroush Shirvan

    2016-08-01

    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.

  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

    2007-02-15

    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. State space modeling of reactor core in a pressurized water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ashaari, A.; Ahmad, T.; M, Wan Munirah W. [Department of Mathematical Science, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Shamsuddin, Mustaffa [Institute of Ibnu Sina, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Abdullah, M. Adib [Swinburne University of Technology, Faculty of Engineering, Computing and Science, Jalan Simpang Tiga, 93350 Kuching, Sarawak (Malaysia)

    2014-07-10

    The power control system of a nuclear reactor is the key system that ensures a safe operation for a nuclear power plant. However, a mathematical model of a nuclear power plant is in the form of nonlinear process and time dependent that give very hard to be described. One of the important components of a Pressurized Water Reactor is the Reactor core. The aim of this study is to analyze the performance of power produced from a reactor core using temperature of the moderator as an input. Mathematical representation of the state space model of the reactor core control system is presented and analyzed in this paper. The data and parameters are taken from a real time VVER-type Pressurized Water Reactor and will be verified using Matlab and Simulink. Based on the simulation conducted, the results show that the temperature of the moderator plays an important role in determining the power of reactor core.

  12. State space modeling of reactor core in a pressurized water reactor

    Science.gov (United States)

    Ashaari, A.; Ahmad, T.; Shamsuddin, Mustaffa; M, Wan Munirah W.; Abdullah, M. Adib

    2014-07-01

    The power control system of a nuclear reactor is the key system that ensures a safe operation for a nuclear power plant. However, a mathematical model of a nuclear power plant is in the form of nonlinear process and time dependent that give very hard to be described. One of the important components of a Pressurized Water Reactor is the Reactor core. The aim of this study is to analyze the performance of power produced from a reactor core using temperature of the moderator as an input. Mathematical representation of the state space model of the reactor core control system is presented and analyzed in this paper. The data and parameters are taken from a real time VVER-type Pressurized Water Reactor and will be verified using Matlab and Simulink. Based on the simulation conducted, the results show that the temperature of the moderator plays an important role in determining the power of reactor core.

  13. Precision spectroscopy with reactor anti-neutrinos

    CERN Document Server

    Huber, P; Huber, Patrick; Schwetz, Thomas

    2004-01-01

    In this work we present an accurate parameterization of the anti-neutrino flux produced by the isotopes 235U, 239Pu and 241Pu in nuclear reactors. We determine the coefficients of this parameterization, as well as their covariance matrix, by performing a fit to spectra inferred from experimentally measured beta spectra. Subsequently we show that flux shape uncertainties play only a minor role in the KamLAND experiment, however, we find that future reactor neutrino experiments to measure the mixing angle $\\theta_{13}$ are sensitive to the fine details of the reactor neutrino spectra. Finally, we investigate the possibility to determine the isotopic composition in nuclear reactors through an anti-neutrino measurement. We find that with a 3 month exposure of a one ton detector the isotope fractions and the thermal reactor power can be determined at a few percent accuracy, which may open the possibility of an application for safeguard or non-proliferation objectives.

  14. Scanning tunneling microscope assembly, reactor, and system

    Science.gov (United States)

    Tao, Feng; Salmeron, Miquel; Somorjai, Gabor A

    2014-11-18

    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. Reactor assessments of advanced bumpy torus configurations

    Energy Technology Data Exchange (ETDEWEB)

    Uckan, N.A.; Owen, L.W.; Spong, D.A.; Miller, R.L.; Ard, W.B.; Pipkins, J.F.; Schmitt, R.J.

    1984-02-01

    Recently, several innovative approaches were introduced for enhancing the performance of the basic ELMO Bumpy Torus (EBT) concept and for improving its reactor potential. These include planar racetrack and square geometries, Andreoletti coil systems, and bumpy torus-stellarator hybrids (which include twisted racetrack and helical axis stellarator - snakey torus). Preliminary evaluations of reactor implications of each approach have been carried out based on magnetics (vacuum) calculations, transport and scaling relationships, and stability properties deduced from provisional configurations that implement the approach but are not necessarily optimized. Further optimization is needed in all cases to evaluate the full potential of each approach. Results of these studies indicate favorable reactor projections with a significant reduction in reactor physical size as compared to conventional EBT reactor designs carried out in the past.

  16. Reactivity control assembly for nuclear reactor. [LMFBR

    Science.gov (United States)

    Bollinger, L.R.

    1982-03-17

    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.

  17. Power Control Method for Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Baang, Dane; Suh, Yongsuk; Park, Cheol [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    Considering safety-oriented design concept and other control environment, we developed a simple controller that provides limiting function of power change- rate as well as fine tracking performance. The design result has been well-proven via simulation and actual application to a TRIGA-II type research reactor. The proposed controller is designed to track the PDM(Power Demand) from operator input as long as maintaining the power change rate lower than a certain value for stable reactor operation. A power control method for a TRIGA-II type research reactor has been designed, simulated, and applied to actual reactor. The control performance during commissioning test shows that the proposed controller provides fine control performance for various changes in reference values (PDM), even though there is large measurement noise from neutron detectors. The overshoot at low power level is acceptable in a sense of reactor operation.

  18. Ceramic oxygen transport membrane array reactor and reforming method

    Science.gov (United States)

    Kelly, Sean M.; Christie, Gervase Maxwell; Robinson, Charles; Wilson, Jamie R.; Gonzalez, Javier E.; Doraswami, Uttam R.

    2016-11-08

    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.

  19. 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

    2011-07-01

    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.

  20. Radiation protection at new reactors

    Energy Technology Data Exchange (ETDEWEB)

    Brissaud, A. [EDF INDUSTRY, Basic Design Department, EDF-SEPTEN, VILLEURBANNE Cedex (France)

    2000-05-01

    The theoritical knowledge and the feedback of operating experience concerning radiations in reactors is now considerable. It is available to the designer in the form of predictive softwares and data bases. Thus, it is possible to include the radiation protection component throughout all the design process. In France, the existing reactors have not been designed with quantified radiation protection targets, although considerable efforts have been made to reduce sources of radiation illustrated by the decrease of the average dose rates (typically a factor 5 between the first 900 MWe and the last 1300 MWe units). The EDF ALARA PROJECT has demonstrated that good practises, radiation protection awareness, careful work organization had a strong impact on operation and maintenance work volume. A decrease of the average collective dose by a factor 2 has been achieved without noticeable modifications of the units. In the case of new nuclear facilities projects (reactor, intermediate storage facility,...), or special operations (such as steam generator replacement), quantified radiation protection targets are included in terms of collective and average individual doses within the frame of a general optimization scheme. The target values by themselves are less important than the application of an optimization process throughout the design. This is because the optimization process requires to address all the components of the dose, particularly the work volume for operation and maintenance. A careful study of this parameter contributes to the economy of the project (suppression of unecessary tasks, time-saving ergonomy of work sites). This optimization process is currently applied to the design of the EPR. General radiation protection provisions have been addressed during the basic design phase by applying general rules aiming at the reduction of sources and dose rates. The basic design optimization phase has mainly dealt with the possibility to access the containment at full

  1. 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

    2000-07-01

    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.)

  2. PCCF flow analysis -- DR Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Calkin, J.F.

    1961-04-26

    This report contains an analysis of PCCF tube flow and Panellit pressure relations at DR reactor. Supply curves are presented at front header pressures from 480 to 600 psig using cold water and the standard 0.236 inch orifice with taper down stream and the pigtail valve (plug or ball) open. Demand curves are presented for slug column lengths of 200 inches to 400 inches using 1.44 inch O.D. solid poison pieces (either Al or Pb-Cd) and cold water with a rear header pressure of 50 psig. Figure 1 is a graph of Panellit pressure vs. flow with the above supply and demand curves and clearly shows the effect of front header pressure and charge length on flow.

  3. Coacervates as prebiotic chemical reactors

    Science.gov (United States)

    Kolb, Vera M.; Swanson, Mercedes; Menger, Fredric M.

    2012-10-01

    Coacervates are colloidal systems that are comprised of two immiscible aqueous layers, the colloid-rich layer, so-called coacervate, and the colloid-poor layer, so-called equilibrium liquid. Although immiscible, the two phases are both water-rich. Coacervates are important for prebiotic chemistry, but also have various practical applications, notably as transport vehicles of personal care products and pharmaceuticals. Our objectives are to explore the potential of coacervates as prebiotic chemical reactors. Since the reaction medium in coacervates is water, this creates a challenge, since most organic reactants are not water-soluble. To overcome this challenge we are utilizing recent Green Chemistry examples of the organic reactions in water, such as the Passerini reaction. We have investigated this reaction in two coacervate systems, and report here our preliminary results.

  4. Replacement reactor to revolutionise magnets

    CERN Document Server

    Atkins, G

    2002-01-01

    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

  5. Dynamic analysis of process reactors

    Energy Technology Data Exchange (ETDEWEB)

    Shadle, L.J.; Lawson, L.O.; Noel, S.D.

    1995-06-01

    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.

  6. 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.

    1989-12-01

    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.

  7. (Meeting on fusion reactor materials)

    Energy Technology Data Exchange (ETDEWEB)

    Jones, R.H. (Pacific Northwest Lab., Richland, WA (USA)); Klueh, R.L.; Rowcliffe, A.F.; Wiffen, F.W. (Oak Ridge National Lab., TN (USA)); Loomis, B.A. (Argonne National Lab., IL (USA))

    1990-11-01

    During his visit to the KfK, Karlsruhe, F. W. Wiffen attended the IEA 12th Working Group Meeting on Fusion Reactor Materials. Plans were made for a low-activation materials workshop at Culham, UK, for April 1991, a data base workshop in Europe for June 1991, and a molecular dynamics workshop in the United States in 1991. At the 11th IEA Executive Committee on Fusion Materials, discussions centered on the recent FPAC and Colombo panel review in the United States and EC, respectively. The Committee also reviewed recent progress toward a neutron source in the United States (CWDD) and in Japan (ESNIT). A meeting with D. R. Harries (consultant to J. Darvas) yielded a useful overview of the EC technology program for fusion. Of particular interest to the US program is a strong effort on a conventional ferritic/martensitic steel for fist wall/blanket operation beyond NET/ITER.

  8. Flexible Conversion Ratio Fast Reactor Systems Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Neil Todreas; Pavel Hejzlar

    2008-06-30

    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.

  9. The Swedish Zero Power Reactor R0

    Energy Technology Data Exchange (ETDEWEB)

    Landergaard, Olof; Cavallin, Kaj; Jonsson, Georg

    1961-05-15

    The reactor R0 is a critical facility built for heavy water and natural uranium or fuel of low enrichment,, The first criticality was achieved September 25, 1959. During a first period of more than two years the R0 will be operated as a bare reactor in order to simplify interpretation of results. The reactor tank is 3. 2 m high and 2. 25 m in diameter. The fuel suspension system is quite flexible in order to facilitate fuel exchange and lattice variations. The temperature of the water can be varied between about 10 and 90 C by means of a heater and a cooler placed in the external circulating system. The instrumentation of the reactor has to meet the safety requirements not only during operation but also during rearrangements of the core in the shut-down state. Therefore, the shut-down state is always defined by a certain low 'safe' moderator level in the reactor tank. A number of safety rods are normally kept above the moderator ready for action. For manual or automatic control of the reactor power a specially designed piston pump is needed, by which the moderator level is varied. The pump speed is controlled from the reactor power error by means of a Ward-Leonard system. Moderator level measurement is made by means of a water gauge with an accuracy of {+-} 0. 1 mm.

  10. Facility for a Low Power Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Chalker, R. G.

    1949-09-14

    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,

  11. Pyrometric fuel particle measurements in pressurised reactors

    Energy Technology Data Exchange (ETDEWEB)

    Hernberg, R.; Joutsenoja, T. [Tampere Univ. of Technology (Finland)

    1996-12-01

    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)

  12. Oxidation performance of graphite material in reactors

    Institute of Scientific and Technical Information of China (English)

    Xiaowei LUO; Xinli YU; Suyuan YU

    2008-01-01

    Graphite is used as a structural material and moderator for high temperature gas-cooled reactors (HTGR). When a reactor is in operation, graphite oxida-tion influences the safety and operation of the reactor because of the impurities in the coolant and/or the acci-dent conditions, such as water ingress and air ingress. In this paper, the graphite oxidation process is introduced, factors influencing graphite oxidation are analyzed and discussed, and some new directions for further study are pointed out.

  13. Sistemas de salvaguardia en reactores EPR

    OpenAIRE

    2015-01-01

    En este documento se describe brevemente el funcionamiento de los diversos sistemas de una planta nuclear operada con un reactor de tipo PWR. Más concretamente, el proyecto se centra en una descripción exhaustiva de los sistemas de salvaguardia y seguridad que regulan el funcionamiento de un reactor de tipo EPR, así como la central nuclear que contiene a dicho reactor. El proceso ha consistido en clasificar y resumir los distintos sistemas que operan en dicha planta, estudiando sus caracterís...

  14. Packed fluidized bed blanket for fusion reactor

    Science.gov (United States)

    Chi, John W. H.

    1984-01-01

    A packed fluidized bed blanket for a fusion reactor providing for efficient radiation absorption for energy recovery, efficient neutron absorption for nuclear transformations, ease of blanket removal, processing and replacement, and on-line fueling/refueling. The blanket of the reactor contains a bed of stationary particles during reactor operation, cooled by a radial flow of coolant. During fueling/refueling, an axial flow is introduced into the bed in stages at various axial locations to fluidize the bed. When desired, the fluidization flow can be used to remove particles from the blanket.

  15. Monitoring and control of anaerobic reactors

    DEFF Research Database (Denmark)

    Pind, Peter Frode; Angelidaki, Irini; Ahring, Birgitte Kiær;

    2003-01-01

    measurements are reviewed in detail. In the sequel, possible manipulated variables, such as the hydraulic retention time, the organic loading rate, the sludge retention time, temperature, pH and alkalinity are evaluated with respect to the two main reactor types: high-rate and low-rate. Finally, the different......The current status in monitoring and control of anaerobic reactors is reviewed. The influence of reactor design and waste composition on the possible monitoring and control schemes is examined. After defining the overall control structure, and possible control objectives, the possible process...

  16. Transients in reactors for power systems compensation

    Science.gov (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

  17. Assessing Pretreatment Reactor Scaling Through Empirical Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lischeske, James J.; Crawford, Nathan C.; Kuhn, Erik; Nagle, Nicholas J.; Schell, Daniel J.; Tucker, Melvin P.; McMillan, James D.; Wolfrum, Edward J.

    2016-12-01

    Pretreatment is a critical step in the biochemical conversion of lignocellulosic biomass to fuels and chemicals. Due to the complexity of the physicochemical transformations involved, predictively scaling up technology from bench- to pilot-scale is difficult. This study examines how pretreatment effectiveness under nominally similar reaction conditions is influenced by pretreatment reactor design and scale using four different pretreatment reaction systems ranging from a 3 g batch reactor to a 10 dry-ton/d continuous reactor. The reactor systems examined were an Automated Solvent Extractor (ASE), Steam Explosion Reactor (SER), ZipperClave(R) reactor (ZCR), and Large Continuous Horizontal-Screw Reactor (LHR). To our knowledge, this is the first such study performed on pretreatment reactors across a range of reaction conditions (time and temperature) and at different reactor scales. The comparative pretreatment performance results obtained for each reactor system were used to develop response surface models for total xylose yield after pretreatment and total sugar yield after pretreatment followed by enzymatic hydrolysis. Near- and very-near-optimal regions were defined as the set of conditions that the model identified as producing yields within one and two standard deviations of the optimum yield. Optimal conditions identified in the smallest-scale system (the ASE) were within the near-optimal region of the largest scale reactor system evaluated. A reaction severity factor modeling approach was shown to inadequately describe the optimal conditions in the ASE, incorrectly identifying a large set of sub-optimal conditions (as defined by the RSM) as optimal. The maximum total sugar yields for the ASE and LHR were 95%, while 89% was the optimum observed in the ZipperClave. The optimum condition identified using the automated and less costly to operate ASE system was within the very-near-optimal space for the total xylose yield of both the ZCR and the LHR, and was

  18. Passive compact molten salt reactor (PCMSR), modular thermal breeder reactor with totally passive safety system

    Energy Technology Data Exchange (ETDEWEB)

    Harto, Andang Widi [Engineering Physics Department, Faculty of Engineering, Gadjah Mada University (Indonesia)

    2012-06-06

    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.

  19. Advanced research reactor fuel development

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chang Kyu; Pak, H. D.; Kim, K. H. [and others

    2000-05-01

    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

  20. Hydrodynamics of multi-phase packed bed micro-reactors

    NARCIS (Netherlands)

    Márquez Luzardo, N.M.

    2010-01-01

    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

  1. Progress of China Experimental Fast Reactor in 2011

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    1 Background Fast reactor is the reactor which realized the chain fission with fast neutron.As an optional type of generation Ⅳ reactor,fast reactor has three characters:1) It can change 238U to 239Pu and raise the uranium resource utilization

  2. Uncertainties in the Anti-neutrino Production at Nuclear Reactors

    OpenAIRE

    Djurcic, Z.(Argonne National Laboratory, Argonne, Illinois, 60439, U.S.A.); Detwiler, J. A.; Piepke, A.; Foster Jr., V. R.; Miller, L.; Gratta, G.

    2008-01-01

    Anti-neutrino emission rates from nuclear reactors are determined from thermal power measurements and fission rate calculations. The uncertainties in these quantities for commercial power plants and their impact on the calculated interaction rates in electron anti-neutrino detectors is examined. We discuss reactor-to-reactor correlations between the leading uncertainties and their relevance to reactor anti-neutrino experiments.

  3. Ex-vessel Steam Explosion Analysis for Pressurized Water Reactor and Boiling Water Reactor

    OpenAIRE

    Matjaž Leskovar; Mitja Uršič

    2016-01-01

    A steam explosion may occur during a severe accident, when the molten core comes into contact with water. The pressurized water reactor and boiling water reactor ex-vessel steam explosion study, which was carried out with the multicomponent three-dimensional Eulerian fuel–coolant interaction code under the conditions of the Organisation for Economic Co-operation and Development (OECD) Steam Explosion Resolution for Nuclear Applications project reactor exercise, is presented and discussed. In ...

  4. 巴基斯坦旁遮普中部横斑腹小鸮的食性%Food habits of the spotted owlet Athene brama in central Punjab, Pakistan

    Institute of Scientific and Technical Information of China (English)

    Muhammad MAHMOOD-UL-HASSAN; Mirza Azhar BEG; Muhammad MUSHTAQ-UL-HASSAN; Shahnaz Ahmed RANA

    2007-01-01

    横斑腹小鸮(Athene brama) 是巴基斯坦旁遮普中部农业生态系统中最常见但研究匮乏的猛禽.我们通过分析吐弃块(n=498)以了解其季节性和地域性食性变化.结果显示:小型哺乳类占所有食物生物量的98.4%,而昆虫类在数量上占据绝对优势 (56.4%).在小型哺乳类食物中,鼠类 (38.8%)是稳定的食物成分.而在昆虫食物中,甲虫最多(42.8%).横斑腹小鸮亦捕食鼩鼱类(2.3%)和鸟类 (1.7%). 昆虫类食物还有蟑螂(6.4%)、臭虫(3.3%)、蝗虫(6.7%)和蚂蚁 (3.2%).小家鼠(Mus musculus)和柔毛鼠(Rattus meltada)在鼠类食物中出现频次最多.不同地区中,Hafizabad 的食物多样性最高(2.07),而秋季的食物多样性最高(1.99).%The spotted owlet Athene brama is the most common but the least studied bird of prey inhabiting the agroecosystems of central Punjab, Pakistan. We analyzed pellets (n=498) of the spotted owlet to understand the seasonal and locality-related changes in its diet. Small mammals contributed 98.4% of the total prey biomass consumed by the owlet. Insects however, were predominant (56.4%) numerically. Among small mammals, rats and mice (38.8%) were a staple food item. Beetles (42.8%) were the most frequent insect prey. Shrews (2.3%) and birds (1.7%) also were consumed. Roaches (6.4%), bugs (3.3%), grasshoppers (6.7%), and ants (3.2%) were the other insect prey consumed by the owlet. The house mouse Mus musculus and the soft-furred field rat Rattus meltada were the most frequent rodents consumed. The greatest dietary diversity (2.07) was recorded at Hafizabad. Fall diet was the most diverse (1.99) of all seasonal samples.

  5. Optimization of a sequence of reactors

    DEFF Research Database (Denmark)

    Vidal, Rene Victor Valqui

    1991-01-01

    Concerns the optimal production of sulphuric acid in a sequence of reactors. Using a suitable approximation to the objective function, this problem can easily be solved using the maximum principle. A numerical example documents the applicability of the suggested approach...

  6. The Bifurcation Behavior of CO Coupling Reactor

    Institute of Scientific and Technical Information of China (English)

    徐艳; 马新宾; 许根慧

    2005-01-01

    The bifurcation behavior of the CO coupling reactor was examined based on the one-dimensional pseudohomogeneous axial dispersion dynamic model. The method of finite difference was used for solving the boundary value problem; the continuation technique and the direct method were applied to determine the bifurcation diagram.The effects of dimensionless adiabatic temperature rise, Damkoehler number, activation energy, heat transfer coefficient and feed ratio on the bifurcation behavior were investigated. It was shown that there existed static bifurcation and the oscillations did not occur in the reactor. The result also revealed that the reactor exhibited at most 1-3-1 multiplilicity patterns within the range of practical possible parameters and the measures, such as weakening the axial dispersion of reactor, enhancing heat transfer, decreasing the concentration of ethyl nitrite, were efficient for avoiding the possible risk of multiple steady states.

  7. Heat pipe reactors for space power applications

    Science.gov (United States)

    Koenig, D. R.; Ranken, W. A.; Salmi, E. W.

    1977-01-01

    A family of heat pipe reactors design concepts has been developed to provide heat to a variety of electrical conversion systems. Three power plants are described that span the power range 1-500 kWe and operate in the temperature range 1200-1700 K. The reactors are fast, compact, heat-pipe cooled, high-temperature nuclear reactors fueled with fully enriched refractory fuels, UC-ZrC or UO2. Each fuel element is cooled by an axially located molybdenum heat pipe containing either sodium or lithium vapor. Virtues of the reactor designs are the avoidance of single-point failure mechanisms, the relatively high operating temperature, and the expected long lifetimes of the fuel element components.

  8. Reactor Antineutrinos: From Confusion to Clarity

    Science.gov (United States)

    Dwyer, Dan

    2016-09-01

    Antineutrinos emitted by nuclear reactors have been a powerful tool for particle physics, demonstrating the existence of these weakly-interacting particles as well as their flavor oscillation. Despite these successes, our understanding of the total flux and energy spectra of reactor antineutrinos has been fraught with problems. I will give a brief overview of the unexpected developments in this field, and discuss upcoming measurements of antineutrinos, beta decays, and nuclear fission which are relevant to these questions. These measurements are expected to clarify many currently murky issues, including the hypothetical oscillation of reactor antineutrinos to sterile states. The results should also provide a unique perspective into the nuclear physics of fission reactors. DOE OHEP DE-AC02-05CH11231.

  9. Chemical reactor modeling multiphase reactive flows

    CERN Document Server

    Jakobsen, Hugo A

    2014-01-01

    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...

  10. µ-reactors for Heterogeneous Catalysis

    DEFF Research Database (Denmark)

    Jensen, Robert

    catalyst surface area by reacting off an adsorbed layer of oxygen with CO. This procedure can be performed at temperatures low enough that sintering of Pt nanoparticles is not an issue. Some results from the reactors are presented. In particular an unexpected oscillation phenomenon of CO-oxidation on Pt...... nanoparticles are presented in detail. The sensitivity of the reactors are currently being investigated with CO oxidation on Pt thin films as a test reaction, and the results so far are presented. We have at this point shown that we are able to reach full conversion with a catalyst area of 38 µm2 with a turn......This thesis is the summary of my work on the µ-reactor platform. The concept of µ-reactors is presented and some of the experimental challenges are outlined. The various experimental issues regarding the platform are discussed and the actual implementation of three generations of the setup...

  11. Corrosion Minimization for Research Reactor Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Eric Shaber; Gerard Hofman

    2005-06-01

    Existing university research reactors are being converted to use low-enriched uranium fue to eliminate the use of highly-enriched uranium. These conversions require increases in fuel loading that will result in the use of elements with more fuel plates, resulting in a net decrease in the water annulus between fuel plates. The proposed decrease in the water annulus raises questions about the requirements and stability of the surface hydroxide on the aluminum fuel cladding and the potential for runaway corrosion resulting in fuel over-temperature incidents. The Nuclear Regulatory Commission (NRC), as regulator for these university reactors, must ensure that proposed fuel modifications will not result in any increased risk or hazard to the reactor operators or the public. This document reviews the characteristics and behavior of aluminum hydroxides, analyzes the drivers for fuel plate corrosion, reviews relevant historical incidents, and provides recommendations on fuel design, surface treatment, and reactor operational practices to avoid corrosion issues.

  12. Interactions of Pellet with Reactor Relevant Plasma

    Institute of Scientific and Technical Information of China (English)

    PENGLilin; DENGBaiquan; YANJiancheng

    2003-01-01

    Extended algorithm has been developed for ablation rate calculations of Li, Be, B impurity pellets and five combinations of solid isotopic hydrogenic H2, HD, D2, DT, T2 pellets. Numerical calculations have been performed for reactor relevant plasma.

  13. Autonomous Control of Space Nuclear Reactors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Nuclear reactors to support future lunar and Mars robotic and manned missions impose new and innovative technological requirements for their control and protection...

  14. Advanced Test Reactor National Scientific User Facility

    Energy Technology Data Exchange (ETDEWEB)

    Frances M. Marshall; Jeff Benson; Mary Catherine Thelen

    2011-08-01

    The Advanced Test Reactor (ATR), at the Idaho National Laboratory (INL), is a large test reactor for providing the capability for studying the effects of intense neutron and gamma radiation on reactor materials and fuels. The ATR is a pressurized, light-water, high flux test reactor with a maximum operating power of 250 MWth. The INL also has several hot cells and other laboratories in which irradiated material can be examined to study material irradiation effects. In 2007 the US Department of Energy (DOE) designated the ATR as a National Scientific User Facility (NSUF) to facilitate greater access to the ATR and the associated INL laboratories for material testing research by a broader user community. This paper highlights the ATR NSUF research program and the associated educational initiatives.

  15. EMERGING TECHNOLOGY BULLETIN: SPOUTED BED REACTOR

    Science.gov (United States)

    The Spouted Bed Reactor (SBR) technology utilizes the unique attributes of the "spouting " fluidization regime, which can provide heat transfer rates comparable to traditional fluid beds, while providing robust circulation of highly heterogeneous solids, concurrent with very agg...

  16. Molten salt reactors - safety options galore

    Energy Technology Data Exchange (ETDEWEB)

    Gat, U. [Oak Ridge National Lab., TN (United States); Dodds, H.L. [Univ. of Tennessee, Knoxville, TN (United States)

    1997-03-01

    Safety features and attributes of molten salt reactors (MSR) are described. The unique features of fluid fuel reactors of on-line continuous processing and the ability for so-called external cooling result in simple and safe designs with low excess reactivity, low fission product inventory, and small source term. These, in turn, make a criticality accident unlikely and reduce the severity of a loss of coolant to where they are no longer severe accidents. A melt down is not an accident for a reactor that uses molten fuel. The molten salts are stable, non-reactive and efficient heat transfer media that operate at high temperatures at low pressures and are highly compatible with selected structural materials. All these features reduce the accident plethora. Freeze valves can be used for added safety. An ultimate safe reactor (U.S.R) is described with safety features that are passive, inherent and non-tamperable (PINT).

  17. Steady State Analysis of Small Molten Salt Reactor : Effect of Fuel Salt Flow on Reactor Characteristics

    OpenAIRE

    Yamamoto, Takahisa; MITACHI, Koshi; Suzuki, Takashi

    2005-01-01

    The Molten Salt Reactor (MSR) is a thermal neutron reactor with graphite moderation and operates on the thorium-uranium fuel cycle. The feature of the MSR is that fuel salt flows inside the reactor during the nuclear fission reaction. In the previous study, the authors developed numerical model with which to simulate the effects of fuel salt flow on the reactor characteristics. In this study, we apply the model to the steady-state analysis of a small MSR system and estimate the effects of fue...

  18. 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

    1993-09-01

    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).

  19. A fast and flexible reactor physics model for simulating neutron spectra and depletion in fast reactors

    Science.gov (United States)

    Recktenwald, Geoff; Deinert, Mark

    2010-03-01

    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.

  20. Developments and Tendencies in Fission Reactor Concepts

    Science.gov (United States)

    Adamov, E. O.; Fuji-Ie, Y.

    This chapter describes, in two parts, new-generation nuclear energy systems that are required to be in harmony with nature and to make full use of nuclear resources. The issues of transmutation and containment of radioactive waste will also be addressed. After a short introduction to the first part, Sect. 58.1.2 will detail the requirements these systems must satisfy on the basic premise of peaceful use of nuclear energy. The expected designs themselves are described in Sect. 58.1.3. The subsequent sections discuss various types of advanced reactor systems. Section 58.1.4 deals with the light water reactor (LWR) whose performance is still expected to improve, which would extend its application in the future. The supercritical-water-cooled reactor (SCWR) will also be shortly discussed. Section 58.1.5 is mainly on the high temperature gas-cooled reactor (HTGR), which offers efficient and multipurpose use of nuclear energy. The gas-cooled fast reactor (GFR) is also included. Section 58.1.6 focuses on the sodium-cooled fast reactor (SFR) as a promising concept for advanced nuclear reactors, which may help both to achieve expansion of energy sources and environmental protection thus contributing to the sustainable development of mankind. The molten-salt reactor (MSR) is shortly described in Sect. 58.1.7. The second part of the chapter deals with reactor systems of a new generation, which are now found at the research and development (R&D) stage and in the medium term of 20-30 years can shape up as reliable, economically efficient, and environmentally friendly energy sources. They are viewed as technologies of cardinal importance, capable of resolving the problems of fuel resources, minimizing the quantities of generated radioactive waste and the environmental impacts, and strengthening the regime of nonproliferation of the materials suitable for nuclear weapons production. Particular attention has been given to naturally safe fast reactors with a closed fuel cycle (CFC

  1. A comparison of radioactive waste from first generation fusion reactors and fast fission reactors with actinide recycling

    Energy Technology Data Exchange (ETDEWEB)

    Koch, M.; Kazimi, M.S.

    1991-04-01

    Limitations of the fission fuel resources will presumably mandate the replacement of thermal fission reactors by fast fission reactors that operate on a self-sufficient closed fuel cycle. This replacement might take place within the next one hundred years, so the direct competitors of fusion reactors will be fission reactors of the latter rather than the former type. Also, fast fission reactors, in contrast to thermal fission reactors, have the potential for transmuting long-lived actinides into short-lived fission products. The associated reduction of the long-term activation of radioactive waste due to actinides makes the comparison of radioactive waste from fast fission reactors to that from fusion reactors more rewarding than the comparison of radioactive waste from thermal fission reactors to that from fusion reactors. Radioactive waste from an experimental and a commercial fast fission reactor and an experimental and a commercial fusion reactor has been characterized. The fast fission reactors chosen for this study were the Experimental Breeder Reactor 2 and the Integral Fast Reactor. The fusion reactors chosen for this study were the International Thermonuclear Experimental Reactor and a Reduced Activation Ferrite Helium Tokamak. The comparison of radioactive waste parameters shows that radioactive waste from the experimental fast fission reactor may be less hazardous than that from the experimental fusion reactor. Inclusion of the actinides would reverse this conclusion only in the long-term. Radioactive waste from the commercial fusion reactor may always be less hazardous than that from the commercial fast fission reactor, irrespective of the inclusion or exclusion of the actinides. The fusion waste would even be far less hazardous, if advanced structural materials, like silicon carbide or vanadium alloy, were employed.

  2. Environmental Information Document: L-reactor reactivation

    Energy Technology Data Exchange (ETDEWEB)

    Mackey, H.E. Jr. (comp.)

    1982-04-01

    Purpose of this Environmental Information Document is to provide background for assessing environmental impacts associated with the renovation, restartup, and operation of L Reactor at the Savannah River Plant (SRP). SRP is a major US Department of Energy installation for the production of nuclear materials for national defense. The purpose of the restart of L Reactor is to increase the production of nuclear weapons materials, such as plutonium and tritium, to meet projected needs in the nuclear weapons program.

  3. Oscillation Parameters with forthcoming Reactor Neutrino Experiments

    CERN Document Server

    Lasserre, Thierry

    2010-01-01

    I review the status of the forthcoming reactor neutrino experiments that toe the cutting edge of neutrino oscillation research. Kilometer baseline oscillation experiments (Double Chooz, Daya Bay, and Reno) will soon play a relevant role providing clean information on the last undetermined neutrino mixing angle !13. A 50-70 km baseline reactor neutrino experiment could later provide the best sensitivity to the !12 mixing angle.

  4. Advanced Reactors Transition Program Resource Loaded Schedule

    Energy Technology Data Exchange (ETDEWEB)

    GANTT, D.A.

    2000-01-12

    The Advanced Reactors Transition (ART) Resource Loaded Schedule (RLS) provides a cost and schedule baseline for managing the project elements within the ART Program. The Fast Flux Test Facility (FETF) activities are delineated through the end of FY 2000, assuming continued standby. The Nuclear Energy (NE) Legacies and Plutonium Recycle Test Reactor (PRTR) activities are delineated through the end of the deactivation process. This revision reflects the 19 Oct 1999 baseline.

  5. Advanced Reactors Transition Program Resource Loaded Schedule

    Energy Technology Data Exchange (ETDEWEB)

    BOWEN, W.W.

    1999-11-08

    The Advanced Reactors Transition (ART) Resource Loaded Schedule (RLS) provides a cost and schedule baseline for managing the project elements within the ART Program. The Fast Flux Test Facility (FFTF) activities are delineated through the end of FY 2000, assuming continued standby. The Nuclear Energy (NE) Legacies and Plutonium Recycle Test Reactor (PRTR) activities are delineated through the end of the deactivation process. This document reflects the 1 Oct 1999 baseline.

  6. The Daya Bay Reactor Neutrino Experiment

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    On Aug.15, 201l, a new large-scale scientific facility in China, Daya Bay Reactor Neutrino Experiment, started to operate. It is located in Daya Bay Nuclear Power Plant in Guangdong Province, around 50kin to both Hong Kong and Shenzhen City. The main scientific goal is to precisely determine the neutrino mixing angle 013 by detecting neutrinos from the reactors at different distances.

  7. Design of an Organic Simplified Nuclear Reactor

    OpenAIRE

    Koroush Shirvan; Eric Forrest

    2016-01-01

    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 attr...

  8. Strengthening IAEA Safeguards for Research Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Reid, Bruce D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Anzelon, George A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Budlong-Sylvester, Kory [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-01

    During their December 10-11, 2013, workshop in Grenoble France, which focused on the history and future of safeguarding research reactors, the United States, France and the United Kingdom (UK) agreed to conduct a joint study exploring ways to strengthen the IAEA’s safeguards approach for declared research reactors. This decision was prompted by concerns about: 1) historical cases of non-compliance involving misuse (including the use of non-nuclear materials for production of neutron generators for weapons) and diversion that were discovered, in many cases, long after the violations took place and as part of broader pattern of undeclared activities in half a dozen countries; 2) the fact that, under the Safeguards Criteria, the IAEA inspects some reactors (e.g., those with power levels under 25 MWt) less than once per year; 3) the long-standing precedent of States using heavy water research reactors (HWRR) to produce plutonium for weapons programs; 4) the use of HEU fuel in some research reactors; and 5) various technical characteristics common to some types of research reactors that could provide an opportunity for potential proliferators to misuse the facility or divert material with low probability of detection by the IAEA. In some research reactors, for example, such characteristics include rapid on-line refueling, and a core design with room for such a large number of assemblies or targets that it is difficult to detect diversion or undeclared irradiation. In addition, infrastructure associated with research reactors, such as hot cells, where plutonium could be separated, could pose a safeguards challenge because, in some cases, they are not declared (because they are not located in the facility or because nuclear materials are not foreseen to be processed inside) and may not be accessible to inspectors in States without an Additional Protocol in force.

  9. Current status of fast reactor physics

    Energy Technology Data Exchange (ETDEWEB)

    Hummel, H.H.

    1979-01-01

    The subject of calculation of reactivity coefficients for fast reactors is developed, starting with a discussion of the status of relevant nuclear data and proceeding to the subjects of group cross section generation and of methods of obtaining reactivity coefficients from group cross sections. Reactivity coefficients measured in critical experiments are compared with calculated values. Dependence of reactivity coefficients on reactor design is discussed. Finally, results of the recent international comparison of calculated reactivity coefficients are presented.

  10. Automatic safety rod for reactors. [LMFBR

    Science.gov (United States)

    Germer, J.H.

    1982-03-23

    An automatic safety rod for a nuclear reactor containing neutron absorbing material and designed to be inserted into a reactor core after a loss-of-flow. Actuation is based upon either a sudden decrease in core pressure drop or the pressure drop decreases below a predetermined minimum value. The automatic control rod includes a pressure regulating device whereby a controlled decrease in operating pressure due to reduced coolant flow does not cause the rod to drop into the core.

  11. Monitoring and control of anaerobic reactors

    DEFF Research Database (Denmark)

    Pind, Peter Frode; Angelidaki, Irini; Ahring, Birgitte Kiær;

    2003-01-01

    control approaches that have been used are comprehensively described. These include simple and adaptive controllers, as well as more recent developments such as fuzzy controllers, knowledge-based controllers and controllers based on neural networks.......The current status in monitoring and control of anaerobic reactors is reviewed. The influence of reactor design and waste composition on the possible monitoring and control schemes is examined. After defining the overall control structure, and possible control objectives, the possible process...

  12. COUPLED FAST-THERMAL POWER BREEDER REACTOR

    Science.gov (United States)

    Avery, R.

    1961-07-18

    A nuclear reactor having a region operating predominantly on fast neutrons and another region operating predominantly on slow neutrons is described. The fast region is a plutonium core and the slow region is a natural uranium blanket around the core. Both of these regions are free of moderator. A moderating reflector surrounds the uranium blanket. The moderating material and thickness of the reflector are selected so that fissions in the uranium blanket make a substantial contribution to the reactivity of the reactor.

  13. Short-baseline reactor neutrino oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Mariani, C. [Department of Physics, Columbia University, New York, NY 10027 (United States)

    2011-08-15

    The neutrino mixing angle {theta}13 is currently a high-priority topic in the field of neutrino physics, with three different reactor neutrino experiments under way, searching for neutrino oscillations induced by this angle. A description of the reactor experiments searching for a non-zero value of {theta}13 is given, together with a discussion of their sensitivity within the next few years.

  14. Reactor Simulator Integration and Testing

    Science.gov (United States)

    Schoenfield, M. P.; Webster, K. L.; Pearson, J. B.

    2013-01-01

    As part of the Nuclear Systems Office Fission Surface Power Technology Demonstration Unit (TDU) project, a reactor simulator (RxSim) test loop was designed and built to perform integrated testing of the TDU components. In particular, the objectives of RxSim testing were 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 because 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 Technical Memorandum 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 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.

  15. Solid oxide electrochemical reactor science.

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, Neal P. (Colorado School of Mines, Golden, CO); Stechel, Ellen Beth; Moyer, Connor J. (Colorado School of Mines, Golden, CO); Ambrosini, Andrea; Key, Robert J. (Colorado School of Mines, Golden, CO)

    2010-09-01

    Solid-oxide electrochemical cells are an exciting new technology. Development of solid-oxide cells (SOCs) has advanced considerable in recent years and continues to progress rapidly. This thesis studies several aspects of SOCs and contributes useful information to their continued development. This LDRD involved a collaboration between Sandia and the Colorado School of Mines (CSM) ins solid-oxide electrochemical reactors targeted at solid oxide electrolyzer cells (SOEC), which are the reverse of solid-oxide fuel cells (SOFC). SOECs complement Sandia's efforts in thermochemical production of alternative fuels. An SOEC technology would co-electrolyze carbon dioxide (CO{sub 2}) with steam at temperatures around 800 C to form synthesis gas (H{sub 2} and CO), which forms the building blocks for a petrochemical substitutes that can be used to power vehicles or in distributed energy platforms. The effort described here concentrates on research concerning catalytic chemistry, charge-transfer chemistry, and optimal cell-architecture. technical scope included computational modeling, materials development, and experimental evaluation. The project engaged the Colorado Fuel Cell Center at CSM through the support of a graduate student (Connor Moyer) at CSM and his advisors (Profs. Robert Kee and Neal Sullivan) in collaboration with Sandia.

  16. Thermal-hydraulic interfacing code modules for CANDU reactors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W.S.; Gold, M.; Sills, H. [Ontario Hydro Nuclear, Toronto (Canada)] [and others

    1997-07-01

    The approach for CANDU reactor safety analysis in Ontario Hydro Nuclear (OHN) and Atomic Energy of Canada Limited (AECL) is presented. Reflecting the unique characteristics of CANDU reactors, the procedure of coupling the thermal-hydraulics, reactor physics and fuel channel/element codes in the safety analysis is described. The experience generated in the Canadian nuclear industry may be useful to other types of reactors in the areas of reactor safety analysis.

  17. Development of computer simulator for coal liquefaction reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yawata, T.; Kobayashi, M.; Ohi, S.; Itho, H.; Hiraide, M. [Nippon Oil Co., Ltd., Tokyo (Japan)

    1995-12-31

    The computer simulator for a coal liquefaction reactor is a useful engineering tool to analyse the data of such reactors. The authors applied this technique to a reactor in the NEDOL process to predict the performance of the reactor, and to assist in the design of a reactor for demonstration plant. The development program of the simulator and its utilization plan are discussed. 4 figs., 2 tabs.

  18. Optimally moderated nuclear fission reactor and fuel source therefor

    Science.gov (United States)

    Ougouag, Abderrafi M.; Terry, William K.; Gougar, Hans D.

    2008-07-22

    An improved nuclear fission reactor of the continuous fueling type involves determining an asymptotic equilibrium state for the nuclear fission reactor and providing the reactor with a moderator-to-fuel ratio that is optimally moderated for the asymptotic equilibrium state of the nuclear fission reactor; the fuel-to-moderator ratio allowing the nuclear fission reactor to be substantially continuously operated in an optimally moderated state.

  19. Design options for a bunsen reactor.

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Robert Charles

    2013-10-01

    This work is being performed for Matt Channon Consulting as part of the Sandia National Laboratories New Mexico Small Business Assistance Program (NMSBA). Matt Channon Consulting has requested Sandia's assistance in the design of a chemical Bunsen reactor for the reaction of SO2, I2 and H2O to produce H2SO4 and HI with a SO2 feed rate to the reactor of 50 kg/hour. Based on this value, an assumed reactor efficiency of 33%, and kinetic data from the literature, a plug flow reactor approximately 1%E2%80%9D diameter and and 12 inches long would be needed to meet the specification of the project. Because the Bunsen reaction is exothermic, heat in the amount of approximately 128,000 kJ/hr would need to be removed using a cooling jacket placed around the tubular reactor. The available literature information on Bunsen reactor design and operation, certain support equipment needed for process operation and a design that meet the specification of Matt Channon Consulting are presented.

  20. Decommissioning of the Salaspils Research Reactor

    Directory of Open Access Journals (Sweden)

    Abramenkovs Andris

    2011-01-01

    Full Text Available In May 1995, the Latvian government decided to shut down the Salaspils Research Reactor and to dispense with nuclear energy in the future. The reactor has been out of operation since July 1998. A conceptual study on the decommissioning of the Salaspils Research Reactor was drawn up by Noell-KRC-Energie- und Umwelttechnik GmbH in 1998-1999. On October 26th, 1999, the Latvian government decided to start the direct dismantling to “green-field” in 2001. The upgrading of the decommissioning and dismantling plan was carried out from 2003-2004, resulting in a change of the primary goal of decommissioning. Collecting and conditioning of “historical” radioactive wastes from different storages outside and inside the reactor hall became the primary goal. All radioactive materials (more than 96 tons were conditioned for disposal in concrete containers at the radioactive wastes depository “Radons” at the Baldone site. Protective and radiation measurement equipment of the personnel was upgraded significantly. All non-radioactive equipment and materials outside the reactor buildings were released for clearance and dismantled for reuse or conventional disposal. Contaminated materials from the reactor hall were collected and removed for clearance measurements on a weekly basis.