WorldWideScience

Sample records for agr reactor windscale

  1. The reliability of thermocouples in the Windscale AGR

    International Nuclear Information System (INIS)

    A brief description is given of two surveys carried out during 1977/78 on Windscale AGR thermocouples. One was concerned with fuel pin thermocouples, the other with channel gas inlet thermocouples. (author)

  2. Development of techniques to dispose of the Windscale AGR heat exchangers

    International Nuclear Information System (INIS)

    In a gas-cooled nuclear power plant the gas side of the heat exchanger tubes becomes contaminated with radioactive deposits carried from the reactor in the coolant stream. In order to dispose of the heat exchangers in the safest and most cost-effective way during plant decommissioning, the deposits have to be removed. In situ chemical decontamination is considered to be the only viable method. This paper describes the research and development of chemical decontamination methods for the Windscale AGR heat exchangers, and the testing of a selected method on an in situ superheater. The research involved characterization of tube corrosion and radioactivity deposits, laboratory testing of chemical reagents on actual tube samples, and the provision and operation of a plant to apply the selected reagent. Disposal of radioactive effluent is an important consideration in chemical decontamination and in the present case was the major factor in determining the process

  3. Windscale advanced gas-cooled reactor (WAGR) decommissioning project overview

    International Nuclear Information System (INIS)

    The current BNFL reactor decommissioning projects are presented. The projects concern power reactor sites at Berkely, Trawsfynydd, Hunterstone, Bradwell, Hinkley Point; UKAEA Windscale Pile 1; Research reactors within UK Scottish Universities at East Kilbride and ICI (both complete); WAGR. The BNFL environmental role include contract management; effective dismantling strategy development; implementation and operation; sentencing, encapsulation and transportation of waste. In addition for the own sites it includes strategy development; baseline decommissioning planning; site management and regulator interface. The project objectives for the Windscale Advanced Gas-Cooled Reactor (WAGR) are 1) Safe and efficient decommissioning; 2) Building of good relationships with customer; 3) Completion of reactor decommissioning in 2005. The completed WAGR decommissioning campaigns are: Operational Waste; Hot Box; Loop Tubes; Neutron Shield; Graphite Core and Restrain System; Thermal Shield. The current campaign is Lower Structures and the remaining are: Pressure vessel and Insulation; Thermal Columns and Outer Vault Membrane. An overview of each campaign is presented

  4. A comparison of measured fission gas release for Windscale AGR fuel irradiated above 18 GWd/tU with those predicted using the computer code MINIPAT D

    International Nuclear Information System (INIS)

    MINIPAT D is a computer code for predicting fission product gas release into the voidage of thermal reactor fuel pins. It also calculates the variation of internal pressure within a pin during irradiation. This paper examines how well the code predicts fission gas release from high burn-up AGR fuel. All the data are provided from the Windscale prototype AGR. Fuel pins included in the investigation came from elements where the mean burn-up exceeded 18 GWd/tU. Values of predicted-to-measured gas release (p/m) for the mean pin in an element have been obtained for pins from eighteen stringers. Whilst there is a spread in the values of p/m, on average MINIPAT D predicts correctly gas release volumes from AGR fuel irradiated above 18 GWd/tU. An analysis conducted in terms of 1n(p/m) gives a standard deviation of approx. 0.7. This is equivalent to a factor of 2 in p/m. The majority of the spread in 1n(p/m) can be attributed to uncertainty in the characterisation of the irradiation conditions and fuel pin properties. The fission gas release measurements for Windscale AGR pins belonging to the same element exhibit a round-the-ring variation which can sometimes be quite significant i.e. a factor of four minimum to maximum. This variation is primarily due to the presence of cross-channel neutron flux tilts during irradiation. It is demonstrated in this paper that MINIPAT D is in general capable of modelling these variations. (author)

  5. Reactor fault simulation at the closure of the Windscale advanced gas-cooled reactor: analysis of reactor transient tests

    International Nuclear Information System (INIS)

    The testing of fault transient analysis methods by direct simulation of fault sequences on a commercial reactor is clearly excluded on safety and economic grounds. The closure of the Windscale prototype advanced gas-cooled reactor (WAGR) therefore offered a unique opportunity to test fault study methods under extreme conditions relatively unfettered by economic constraints, although subject to appropriate safety regulations. One aspect of these important experiments was a series of reactor transient tests. The objective of these reactor transients was to increase confidence in the fault study computer models used for commercial AGR safety assessment by extending their range of validation to cover large amplitude and fast transients in temperature, power and flow, relevant to CAGR faults, and well beyond the conditions achievable experimentally on commercial reactors. A large number of tests have now been simulated with the fault study code KINAGRAX. Agreement with measurement is very good and sensitivity studies show that such discrepancies as exist may be due largely to input data errors. It is concluded that KINAGRAX is able to predict steady state conditions and transient amplitudes in both power and temperature to within a few percent. (author)

  6. The nuclear reactor accident at Windscale - October, 1957: Environmental aspects

    International Nuclear Information System (INIS)

    The nature and cause of the nuclear reactor accident at Windscale in October, 1957, have been described in the summary report of the Committee of Inquiry set up by the Atomic Energy Authority. This report was published in a Command Paper Atomic Energy Office, 1957). The events leading up to the accident occurred on the 8th October, during a routine release of the energy which had become stored in the graphite moderator as a result of the normal operation of the reactor. The Committee concluded that the accident had been caused by local overheating of the uranium fuel elements, the canning of which then failed exposing the uranium and allowing it to oxidize. The temperatures in the affected channels continued to rise, leading to the combustion of the graphite. The amount of radioactivity released during the accident is not known precisely, but approximate estimates were made from the measurements of the radioactive iodine deposited on the ground in this country, and from measurements on air filters obtained both in the United Kingdom and on the continent of Europe

  7. Results of gamma-scanning measurements on Windscale AGR stringer Mk4/S46 and implications for civil AGRs

    International Nuclear Information System (INIS)

    Axial rating distributions in a WAGR fuel stringer were determined retrospectively using the measured gamma count rates from five fission products after cooling times of 70 to 100 days. The results from all five isotopes were in general agreement with predictions using the Windscale code CAMPARI, but revealed mutually consistent discrepancies with prediction near the top axial reflector. The measurements were conducted to test the gamma-scanning apparatus and methods of analysis in preparation for the post irradiation examination of CAGR fuel. It was concluded from the results that accuracies of +- 2% to +- 3% (1 sigma) should be attainable in the determination of relative ratings using the measured gamma count rates from the isotopes 140Ba, 103Ru, 95Zr, 144Ce and 137Cs. The accuracies will, however, depend on the type of fuel being examined and the fission product used. In particular, care must be taken when using 137Cs since it may migrate from its point of formation, and cooling times of less than 110 days must be achieved to measure relative concentrations of the short-lived isotope 140Ba with sufficient accuracy. (author)

  8. Measurement of sulphur-35 in the coolant gas of the Windscale Advanced Gas-Cooled Reactor

    International Nuclear Information System (INIS)

    Sulphur is an important element in some food chains and the release of radioactive sulphur to the environment must be closely controlled if the chemical form is such that it is available or potentially available for entering food chains. The presence of sulphur-35 in the coolant gas of the Windscale Advanced Gas-Cooled Reactor warranted a study to assess the quantity and chemical form of the radioactive sulphur in order to estimate the magnitude of the potential environmental hazard which might arise from the release of coolant gas from Civil Advanced Gas-Cooled Reactors. A combination of gas chromatographic and radiochemical analyses revealed carbonyl sulphide to be the only sulphur-35 compound present in the coolant gas of the Windscale Reactor. The concentration of carbonyl sulphide was found to lie in the range 40 to 100 x 10-9 parts by volume and the sulphur-35 specific activity was about 20 mCi per gramme. The analytical techniques are described in detail. The sulphur-35 appears to be derived from the sulphur and chlorine impurities in the graphite. A method for the preparation of carbonyl sulphide labelled with sulphur-35 is described. (author)

  9. Microscopical examination of carbon deposits formed in the Windscale advanced gas cooled reactor

    International Nuclear Information System (INIS)

    Methods are described of sampling and examining carbon deposits on fuel cladding in the Windscale advanced gas-cooled reactor. Deposition is observed on fuel cladding in both the reactor core and experimental loops in carbon dioxide coolants containing various amounts of carbon monoxide and methane. Deposit distribution over the cladding surface indicated that nucleation is dependent on local surface conditions. Microscopical examination showed that deposit thickness increases by carbon filament growth into the coolant gas stream and that the process can be markedly influenced by metallic impurities. There is evidence that nickel can play a particularly significant role in deposition in loop experiments but similar effects have not been observed in the reactor core. (author)

  10. Some Windscale experience of the underwater examination of water reactor fuel assemblies

    International Nuclear Information System (INIS)

    Windscale Nuclear Laboratories have been involved in the underwater post irradiation examination of irradiated water reactor fuel since the early 1970's. Since the work of the laboratories covers a wide range of fuel types, the equipment has had to be capable of handling any design, long or short, circular or square. There has so far been no element of routine work in the tasks performed at Windscale, for in this period fuel assemblies from 9 LWR's and WSGHWR have been examined successfully. Individual jobs have ranged from visual examination which may be carried out at several magnifications, to the complete breakdown of a PWR assembly to its separate rods and grids. Between these limits rod bow and rod diameter have been measured, rod withdrawal forces determined, and eddy current test methods devised. Cutting equipment has been used for a variety of dismantling tasks, and underwater cameras have been employed for monochrome and colour photography, using standard and macro lenses. The equipment is described. (author)

  11. The Windscale inquiry

    International Nuclear Information System (INIS)

    The three questions posed by Mr. Justice Parker at the onset of the enquiry, namely, 1. Should oxide fuel from UK reactors be reprocessed in this country. 2. If yes, should it be at Windscale and 3. If yes, should the plant be used to process foreign fuels are discussed in relation to the findings of the enquiry. (UK)

  12. Description of the advanced gas cooled type of reactor (AGR)

    International Nuclear Information System (INIS)

    The present report comprises a technical description of the Advanced Gas cooled Reactor (AGR), a reactor type which has only been built in Great Britain. 14 AGR reactors have been built, located at 6 different sites and each station is supplied with twin-reactors. The Torness AGR plant on the Lothian coastline of Scotland, 60 km east of Edinburgh, has been chosen as the reference plant and is described in some detail. Data on the other 6 stations, Dungeness B, Hinkely Point B, Hunterston G, Hartlepool, Heysham I and Heysham II, are given only in tables with a summary of design data. Where specific data for Torness AGR has not been available, corresponding data from other AGR plans has been used, primarily from Heysham II, which belongs to the same generation of AGR reactors. The information presented is based on the open literature. The report is written as a part of the NKS/RAK-2 subproject 3: 'Reactors in Nordic Surroundings', which comprises a description of nuclear power plants neighbouring the Nordic countries. (au) 11 refs

  13. Nuclear-reactor accidents: Chernobyl, TMI, and Windscale. January 1974-September 1988 (Citations from Pollution Abstracts). Report for January 1974-September 1988

    International Nuclear Information System (INIS)

    This bibliography contains citations concerning studies and measurements of the radiological consequences of nuclear-reactor accidents. The citations cover specifically the Chernobyl reactor in the USSR, the Three Mile Island (TMI) reactor in the US, and the Windscale reactor in the UK. Included are detection and monitoring of the fallout, the resultant runoff into rivers, lakes, and the sea, the radiation effects on people, and the transfrontier radioactive contamination of the environment. (Contains 105 citations fully indexed and including a title list.)

  14. Progress in the development of tooling and dismantling methodologies for the Windscale advanced gas cooled reactor (WAGR)

    International Nuclear Information System (INIS)

    Decommissioning of the Windscale Advanced Gas-Cooled Reactor (WAGR) is a major UK reactor decommissioning project co-funded by the UK Government, the European Commission and Magnox Electric. WAGR was a CO2 cooled, graphite moderated reactor which served as a test bed for the development of Advanced Gas-Cooled Reactor technology in the UK. It operated from 1963 until shutdown in 1981. AEA Technology plc are currently the Managing Agents on behalf of UKAEA for the WAGR decommissioning project and are responsible for the co-ordination of the project up to the point when the contents of the reactor core and associated radioactive materials are removed and either disposed of or packaged for disposal at some time in the future. Decommissioning has progressed to the point where the reactor has been dismantled down to the level of the hot gas collection manifold with the removal of the top biological shield, the refuelling standpipes and the top section of the reactor pressure vessel. The 4 heat exchangers have also been removed and committed to shallow land burial. This paper describes the work carried out by AEA Technology under separate contracts of UKAEA in developing some of the equipment and deployment methods for the next phase of active operations required in preparation for the dismantling of the core structure. Most recent work has concentrated on the development of specialist tooling for removal of items of operational waste stored within the reactor core, equipment for cutting and removal of the highly radioactive stainless steel 'loop' pressure tubes, diamond wire cutting equipment for sectioning large diameter pipework, and equipment for dismantling the reactor neutron shield. The paper emphasises the process of adaptation and extension of existing technologies for cost-effective application in the decommissioning environment, the need for adequate forward planning of decommissioning methodologies together with large-scale 'mock-up' testing of equipment to

  15. Nuclear reactor accidents: Chernobyl, TMI (Three Mile Island), and Windscale. January 1974-September 1989 (Citations from Pollution Abstracts). Report for January 1974-September 1989

    International Nuclear Information System (INIS)

    This bibliography contains citations concerning studies and measurements of the radiological consequences of nuclear reactor accidents. The citations cover specifically the Chernobyl reactor in the USSR, the Three Mile Island (TMI) reactor in the US, and the Windscale reactor in the UK. Included are detection and monitoring of the fallout, the resultant runoff into rivers, lakes, the sea, the radiation effects on people, and the transfrontier radio ative contamination of the environment. (This updated bibliography contains 164 citations, 59 of which are new entries to the previous edition.)

  16. Advanced gas-cooled reactors (AGR)

    International Nuclear Information System (INIS)

    The paper describes the advanced gas-cooled reactor system, Hunterston ''B'' power station, which is a development of the earlier natural uranium Magnox type reactor. Data of construction, capital cost, operating performance, reactor safety and also the list of future developments are given

  17. An assessment of the radiological impact of the Windscale reactor fire, October 1957

    International Nuclear Information System (INIS)

    The assessment described has involved a review of previously unpublished data, in order to establish the quantities of nuclides released from materials undergoing irradiation in the pile at the time of the fire. Of these additional nuclides, only polonium-210 has been shown to make a significant contribution to the estimate of the collective effective dose equivalent to the population from the Windscale fire. The previous estimate of 1.2 x 103 man Sv for the collective effective dose equivalent commitment to the population of the UK and Northern Europe has been increased by 67% to 2.0 x 103 man Sv. This change is within the range of uncertainty of the original estimate. The influence of the addition on the theoretical estimate of the upper limit of possible health effects is discussed in this addendum and its foreword. With the inclusion of the additional nuclides, the inhalation pathway has become the overall largest contributor to this population dose, followed by the milk ingestion pathway; the largest nuclide contribution comes from iodine-131, followed by polonium-210. Some perspective may be provided on the contribution due to polonium-210 by noting that it is approximately one-tenth of that arising annually due to naturally occurring polonium-210, and less than one-hundredth of that due annually to the total natural background radiation. (author)

  18. Methods of Control-Rod Calibration in the Windscale Advanced Gas-Cooled Reactor

    International Nuclear Information System (INIS)

    Different techniques were used to calibrate control rods and to measure individual rod worths during the commissioning of the WAGR. These methods are described and the results are presented. The methods described are: (a ) Air poisoning - Changes in air pressure allow axial movement of rods at the critical condition. Thus rod movement can be related to pressure variation which is equivalent to a reactivity change. Also, rod slope measurements can be made for different rod insertions. (b) Rod slopes - The rods are withdrawn to make the reactor supercritical; then later they are inserted to make the reactor subcritical. From a measurement of the doubling and halving times the change in reactivity between the super- and subcritical states can be determined.- (c ) Absorber addition and withdrawal - The number of fixed localized absorbers is varied to give a method similar to the use of uniform air poisoning. (d) Pulsatron - This technique is used to give subcritical measurements of rod worth. (e) Rod run-in - The reactor is initially critical, and then the rods are run into the core. Analysis of the flux response relates reactivity to rod movement. (author)

  19. Performance of AGR fuel - past, present and future

    International Nuclear Information System (INIS)

    The evolution of the Commercial Advanced Gas-cooled Reactor (CAGR) fuel element design, from trials in the Windscale AGR prototype to fuel currently being loaded, is briefly described. Fuel element performance has been monitored by an extensive post-irradiation examination programme, the results of which have been used to confirm or improve all aspects of the fuel design. As the CAGR system matures, there is less need for further design changes. Increases in discharge irradiation and improvements in manufacturing methods will further improve the economics of the AGR system. In order to achieve this, modest changes to the current successful fuel element design are being implemented or investigated. (Author)

  20. CO2 direct cycles suitable for AGR type reactors

    International Nuclear Information System (INIS)

    The perspectives given by the gas turbines under pressure, to build simple nuclear power plants and acieving significantly high yield, are specified. The CO2 is characterised by by good efficiency under moderate temperature (500 to 750 Celsius degrees), compactness and the simpleness of machines and the safe exploitation (supply, storage, relief cooling, thermosyphon). The revision of thermal properties of the CO2 and loss elements show that several direct cycles would fit in particular to the AGR type reactors. Cycles that would diverge a little from classical models and able to lead to power and heat generation can lead by simple means to the best results. Several satisfying solutions present for the starting up, the power regulation and the stopping. The nuclear power plant components and the functioning safety are equally considered in the present report. The conclusions stimulate the studies and realizations of carbon dioxide gas turbines in when approprite

  1. A comparison of predicted and measured graphite moderator behaviour during 16 years' operation of the Windscale advanced gas-cooled reactor

    International Nuclear Information System (INIS)

    The Windscale AGR has operated since January 1963 at a cumulative load factor of nearly 70% during which time the peak irradiation damage dose has built up to more than 5x10 n/cm2 (equivalent DIDO nickel), well beyond its original design life. This paper recounts the findings of monitoring measurements on the moderator at high exposure levels with regard to radiolytic oxidation and various aspects of dimensional change behaviour. It is shown that the measured dimensional changes are in good agreement with predictions based on small specimens irradiated in MTR's, thus confirming the absence of any size effect and adding confidence to predictive methods. However, recent measurements of channel straightness show that the observed distortions are only about 10% of the maximum predictions, perhaps due to localised creep at the brick ends creating flats which impart some stability to the columns of moderator bricks. The magnitude of radiolytic oxidation determined by trepanning specimens from the core in 1976 was found to be only about 5%, whereas it was thought possible that peak weight losses would conceivably be as high as 11% due to the depleted concentration of methane inhibitor reaching the brick interior by diffusion processes. It has subsequently been shown by calculation that this result is consistent with the existence of radial pressure drops across the moderator brick walls giving greater penetration of methane inhibitor. (author)

  2. The Windscale fire in 1957

    International Nuclear Information System (INIS)

    On thursday 10. october 1957 a fire was detected in the reactor number 1 at the Windscale plant. It was the beginning of the first major nuclear accident that led to radioactive contamination outside the site. The 2 reactors at Windscale were designed to produce plutonium, each reactor was made up of 70.000 fuel elements and 2000 tons of graphite and was cooled by a powerful air flow. Air was driven through the core by 8 huge propellers and was rejected through a 125 m-high chimney. The Wigner energy played a crucial role in that accident. Whenever graphite is irradiated at low temperature, a part of the energy of the incident neutrons is stored inside the graphite in the form of potential energy due to the displacement of atoms inside the crystal lattice. The Wigner energy was a strong constraint to the reactor operation and a Wigner energy relieving heating of graphite was due to be performed regularly. It was during the 9. heating process that graphite caught fire. (A.C.)

  3. Windscale - power versus pollution

    International Nuclear Information System (INIS)

    Protests from British environmental groups, scientists, politicians and private citizens has forced the Government to postpone a decision on plans to create the world's largest nuclear fuel oxide reprocessing complex at Windscale, on the north-west coast of England. Subjects considered here are the vast increase in the the quantity of lethal nuclear waste stored at Windscale, the risk of explosion or plant malfunction causing radioactive fall-out, the increased radioactive discharge into the Irish Sea and into the atmosphere and the danger of terrorism or sabotage. It is stated that critics of the Windscale project have yet to be convinced that the nuclear power industry is as risk-free as its proponents maintain in public statements. To satisfy the great anxieties shared by a large number of people about the expansion plan, a full public inquiry is essential. (U.K.)

  4. The Windscale enquiry

    International Nuclear Information System (INIS)

    Comments are made on some of the recommendations in the inspector's report on the proposal to build a reprocessing plant for thermal oxide fuel at Windscale, and on some of the arguments put forward at the public inquiry. The subjects discussed are: safety and the assessment of risk; treatment of highly radioactive wastes; alternative energy sources and energy conservation by domestic thermal insulation; and the question whether processing for foreign countries at Windscale might increase the risks of nuclear weapons proliferation. The paper ends with comments on the press coverage of the public inquiry and on the standard of the inquiry itself. (U.K.)

  5. The Windscale Fire, October 1957

    International Nuclear Information System (INIS)

    This report contains a review of the scientific literature relating to the Windscale reactor accident in 1957. In particular, dose calculations are examined. It is found that hitherto no computation of the collective dose has been published. The report finds that computation of collective doses according to internationally accepted models leads to the conclusion that the accident produced several late effects such as deaths from cancer. Included is a survey of official statistics including thyroid cancer mortality, other cancers, infant mortality and stillbirths. No significant deviation from the expected rates has been observed in those areas affected by the fall-out from the accident, and thus it can be concluded that the dose-effect models are not wildly inaccurate. It is concluded, however, that in view of the latent period for thyroid cancers, and of the low incidence of these diseases, a more detailed survey would present an opportunity to test the accuracy of the thyroid dose-effect model. (author)

  6. The Windscale experiment

    International Nuclear Information System (INIS)

    The discharge of radioactive waste into the Irish Sea from the Windscale reprocessing plant in Cumbria is discussed from an Irish viewpoint. A history of accidents at the plant is reviewed, and past, present and future levels of discharge to the environment are outlined. The effect on the Irish population of discharges to the marine environment is evaluated by consideration of the food chain and the exposure pathways to man, in particular the concentration of radioactive caesium and plutonium in the flesh of fish in the Irish Sea. The general health effects attributed to radiation exposures are given, and a cluster of Downs Syndrome babies born to mothers who were at the same school in Co. Louth is attributed to increased exposure during the 1957 fire at the Windscale plant. The author concludes that, because of military implications and the need for plutonium for nulcear weapons, the reprocessing plant will continue to operate, but with greatly reduced levels of discharges permitted

  7. Penney's Windscale thoughts

    International Nuclear Information System (INIS)

    The paper concerns the official file on the nuclear fire at Windscale in October 1957, which was written by Sir William Penney. The file was based on a 10-day investigation, and describes the physical causes and consequences of the fire. The events of the accident are described, along with the political events of the time concerning the U.S.A. and nuclear weapons, attempts to put out the fire, iodine fall-out in the milk, and polonium 210 contamination. (UK)

  8. The Windscale Advanced Gas Cooled Reactor (WAGR) Decommissioning Project A Close Out Report for WAGR Decommissioning Campaigns 1 to 10 - 12474

    Energy Technology Data Exchange (ETDEWEB)

    Halliwell, Chris [Sellafield Ltd, Sellafield (United Kingdom)

    2012-07-01

    The reactor core of the Windscale Advanced Gas-Cooled Reactor (WAGR) has been dismantled as part of an ongoing decommissioning project. The WAGR operated until 1981 as a development reactor for the British Commercial Advanced Gas cooled Reactor (CAGR) power programme. Decommissioning began in 1982 with the removal of fuel from the reactor core which was completed in 1983. Subsequently, a significant amount of engineering work was carried out, including removal of equipment external to the reactor and initial manual dismantling operations at the top of the reactor, in preparation for the removal of the reactor core itself. Modification of the facility structure and construction of the waste packaging plant served to provide a waste route for the reactor components. The reactor core was dismantled on a 'top-down' basis in a series of 'campaigns' related to discrete reactor components. This report describes the facility, the modifications undertaken to facilitate its decommissioning and the strategies employed to recognise the successful decommissioning of the reactor. Early decommissioning tasks at the top of the reactor were undertaken manually but the main of the decommissioning tasks were carried remotely, with deployment systems comprising of little more than crane like devices, intelligently interfaced into the existing structure. The tooling deployed from the 3 tonne capacity (3te) hoist consisted either purely mechanical devices or those being electrically controlled from a 'push-button' panel positioned at the operator control stations, there was no degree of autonomy in the 3te hoist or any of the tools deployed from it. Whilst the ATC was able to provide some tele-robotic capabilities these were very limited and required a good degree of driver input which due to the operating philosophy at WAGR was not utilised. The WAGR box proved a successful waste package, adaptable through the use of waste box furniture specific to the

  9. Society's response to Windscale

    International Nuclear Information System (INIS)

    In surveying public attitudes to the proposals for expansion at Windscale consideration is given to events leading to the public enquiry, comments on the inquiry itself, and the issues raised in discussions and demonstrations which followed. Some drawbacks are pointed out concerning alternative sources of energy which have been suggested. The question of risk and some recent estimations or risks involved in various industries and activities are discussed. The philosophy of protest is discussed and attention is paid to the suggestion for special procedures for public consultation as envisaged by the Secretary of State for the Environment. (U.K.)

  10. Status of the NGNP Fuel Experiment AGR-2 Irradiated in the Advanced Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Blaine Grover

    2012-10-01

    The United States Department of Energy’s Next Generation Nuclear Plant (NGNP) Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating up to seven separate low enriched uranium (LEU) tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States, and will be irradiated over the next several years to demonstrate and qualify new TRISO coated particle fuel for use in high temperature gas reactors. The goals of the irradiation experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing. The experiments, which will each consist of at least six separate capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control of each capsule. The sweep gas will also have on-line fission product monitoring on its effluent to track performance of the fuel in each individual capsule during irradiation. The first experiment (designated AGR-1) started irradiation in December 2006 and was completed in November 2009. The second experiment (AGR-2), which utilized the same experiment design as well as control and monitoring systems as AGR-1, started irradiation in June 2010 and is currently scheduled to be completed in April 2013. The design of this experiment and support systems will be briefly discussed, followed by the progress and status of the experiment to date.

  11. Irradiation performance of AGR-1 high temperature reactor fuel

    Energy Technology Data Exchange (ETDEWEB)

    Paul A. Demkowicz; John D. Hunn; Robert N. Morris; Charles A. Baldwin; Philip L. Winston; Jason M. Harp; Scott A. Ploger; Tyler Gerczak; Isabella J. van Rooyen; Fred C. Montgomery; Chinthaka M. Silva

    2014-10-01

    The AGR-1 experiment contained 72 low-enriched uranium oxide/uranium carbide TRISO-coated particle fuel compacts in six capsules irradiated to burnups of 11.2 to 19.5% FIMA, with zero TRISO coating failures detected during the irradiation. The irradiation performance of the fuel–including the extent of fission product release and the evolution of kernel and coating microstructures–was evaluated based on detailed examination of the irradiation capsules, the fuel compacts, and individual particles. Fractional release of 110mAg from the fuel compacts was often significant, with capsule-average values ranging from 0.01 to 0.38. Analysis of silver release from individual compacts indicated that it was primarily dependent on fuel temperature history. Europium and strontium were released in small amounts through intact coatings, but were found to be significantly retained in the outer pyrocrabon and compact matrix. The capsule-average fractional release from the compacts was 1×10 4 to 5×10 4 for 154Eu and 8×10 7 to 3×10 5 for 90Sr. The average 134Cs release from compacts was <3×10 6 when all particles maintained intact SiC. An estimated four particles out of 2.98×105 experienced partial cesium release due to SiC failure during the irradiation, driving 134Cs release in two capsules to approximately 10 5. Identification and characterization of these particles has provided unprecedented insight into the nature and causes of SiC coating failure in high-quality TRISO fuel. In general, changes in coating morphology were found to be dominated by the behavior of the buffer and inner pyrolytic carbon (IPyC), and infrequently observed SiC layer damage was usually related to cracks in the IPyC. Palladium attack of the SiC layer was relatively minor, except for the particles that released cesium during irradiation, where SiC corrosion was found adjacent to IPyC cracks. Palladium, silver, and uranium were found in the SiC layer of irradiated particles, and characterization

  12. The Windscale 1957 fire and the lessons gained

    International Nuclear Information System (INIS)

    In 1957 the Windscale-1 reactor (UK), devoted to military nuclear weapon research, was destroyed by fire during an operation of Wigner energy evacuation from the graphite core. This accident was the most serious known before the TMI event in 1979 and the radioactive releases in the atmosphere were highly greater. This paper gives a general description of the Windscale reactors principle with some details about the Wigner effect and the graphite annealing procedure developed to counterbalance this effect. Then, it describes the accident itself and the emergency procedure followed to extinguish the fire. Finally, as a consequence of the accident, several analyses and inquiries were carried out to study the details of the accident and to determine its environmental impact. These studies have led to the creation of the U.K. Nuclear Inspectorate. (J.S). 4 refs

  13. The long term storage of advanced gas-cooled reactor (AGR) fuel

    International Nuclear Information System (INIS)

    The approach being taken by BNFL in managing the AGR lifetime spent fuel arisings from British Energy reactors is given. Interim storage for up to 80 years is envisaged for fuel delivered beyond the life of the Thorp reprocessing plant. Adopting a policy of using existing facilities, to comply with the principles of waste minimisation, has defined the development requirements to demonstrate that this approach can be undertaken safely and business issues can be addressed. The major safety issues are the long term integrity of both the fuel being stored and structure it is being stored in. Business related issues reflect long term interactions with the rest of the Sellafield site and storage optimisation. Examples of the development programme in each of these areas is given. (author)

  14. Windscale Report: a nuclear apologia

    International Nuclear Information System (INIS)

    Government representatives have pointed repeatedly with pride to Britain's longest nuclear planning inquiry, The Windscale Inquiry, as a model of open examination of a sensitive nuclear proposal. The official Report of the Windscale Inquiry, published in March 1978, bears little relationship to the proceedings of the Inquiry, according to the author. Instead, the Report is a heavy-handed nuclear apologia, he says, so clumsily one-sided as to provoke unease even among many Britons previously unmoved by the issue which gave rise to the inquiry. Windscale, built following WW II to produce plutonium for Britain's nuclear weapons, is now operated by British Nuclear Fuels Ltd. In 1973, BNFL began to plan construction of a new full-scale oxide-fuel reprocessing plant. Protests delayed construction until the inquiry was planned and the inquiry team was formulated in March 1977. When the Inquiry ended, the inspector closeted himself to write the Report. The Report recommended that the oxide fuel reprocessing plant be built immediately. BNFL had asserted that the proposed thermal oxide reprocessing plant, THORP, was necessary for the management of spent fuel from British and other nuclear plants; that it was desirable for ''energy conservation,'' by recovering uranium and plutonium for re-use; that radioactive emissions within and outside the plant would pose no hazard; and that the servicing of foreign customers would not increase the risk of proliferation of nuclear weapons, but would rather help to persuade other countries not to reprocess their own fuel. The inspector agreed without qualification and with emphasis. In doing so he made no attempt even to describe the detailed evidence on either side, or to discuss the cases advanced by objectors. The author discusses the principal conclusions of the report and cites its futility

  15. The economics of nuclear fuel reprocessing: a case study of the Windscale Thorp plant

    International Nuclear Information System (INIS)

    The economics of the THORP fuel reprocessing plant under construction at Windscale in Cumbria are discussed, comparing the costs of reprocessing with disposal of oxide fuels. The possibility of a fast reactor programme in the UK is then introduced into the discussion and the economics of using reprocessed plutonium as the fuel considered. (U.K.)

  16. Design and Status of the NGNP Fuel Experiment AGR-3/4 Irradiated in the Advanced Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Blaine Grover

    2012-10-01

    The United States Department of Energy’s Next Generation Nuclear Plant (NGNP) Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating up to seven separate low enriched uranium (LEU) tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States, and will be irradiated over the next several years to demonstrate and qualify new TRISO coated particle fuel for use in high temperature gas reactors. The goals of the irradiation experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing. The experiments, which will each consist of at least six separate capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control of each capsule. The sweep gas will also have on-line fission product monitoring on its effluent to track performance of the fuel in each individual capsule during irradiation. The first experiment (designated AGR-1) started irradiation in December 2006 and was completed in November 2009. The second experiment (AGR-2) started irradiation in June 2010 and is currently scheduled to be completed in April 2013. The third and fourth experiments have been combined into a single experiment designated AGR-3/4, which started its irradiation in December 2011 and is currently scheduled to be completed in November 2013. Since the purpose of this experiment is to provide data on fission product migration and retention in the NGNP reactor, the design of this experiment is

  17. Decommissioning of Windscale pile 1

    International Nuclear Information System (INIS)

    The Windscale Piles were constructed in the late 1940's primarily for the production of plutonium in support of the British atomic weapons programme. In 1957 Pile 1 suffered a fire during the routine release of stored Wigner energy by nuclear heating. Following the fire as much material as possible was recovered, an inventory and status report prepared and the pile sealed and placed under surveillance and maintenance, the only practicable option at the time. Over the last decade in addition to general improvements in routine monitoring equipment there has been extensive investigative work carried out to better understand the damage caused by the fire and assess the options for further action. These studies concluded that the preferred option was for the Pile core to be removed, treated and packaged for intermediate storage prior to final disposal. The paper will describe the core investigations, the assessed conditions, and the options considered. It will also describe the tendering process to allow contractors to propose solutions against a cardinal point specification, the outline of the preferred solution and the progress of the work to date. (author)

  18. A UKAEA review of gas-cooled reactors in the United Kingdom

    International Nuclear Information System (INIS)

    The commercial use of nuclear power for electrical generation commenced in the UK in the 1950s with the Calder Hall reactors. Based on this concept, eighteen commercial reactor units, with two further units outside the UK, were constructed and have been in operation for periods ranging from 10 to 19 years. The paper reviews this experience mainly from the aspects of safety and the achieved costs, which compare favourably with current figures for fossil fired generation. The further development of the gas-cooled system in the UK commenced with the construction of the Windscale AGR, which came into operation in 1962. This led to the ordering of 14 large commercial AGR units, 4 of which have been in service since 1976, 6 are at an advanced stage of construction and 4 are at an early stage of construction. The paper reviews the main safety features of the AGR and considers the costs, taking achieved costs for the units which are in service and a combination of historical costs and projected costs for the units under construction. Again a clear advantage over fossil fuelled stations is shown. The paper also includes a preliminary account of the use of the prototype AGR at Windscale for the series of experiments concerning plateout, over-temperature in the fuel and simulated fault transients in the core which were carried out earlier in 1981. (author)

  19. Five years operational experience of a mini-computer based auto-control system on the windscale advanced gas cooled reactor

    International Nuclear Information System (INIS)

    For the two 600 psi experimental loop facilities it was decided to use an auto-control system based on a mini-computer. In order to ease the job of re-programming for each new set of calculations that part of the software was implemented in BASIC. The scanning routines and other routines controlling the interfaces to the actuators were written in assembler language and were not designed to be modified between experiments. Data from the two experimental loop facilities is also fed into a separate minicomputer based data logging and alarm system which serves the whole reactor system. For ultimate safety protection the loops are also connected into the completely independent analogue reactor trip system. (orig./HP)

  20. A review of irradiated fuel particle releases from the Windscale Piles, 1950-1957

    International Nuclear Information System (INIS)

    Radiological assessments have assumed that the mass of irradiated uranium oxide particles inadvertently released to the atmosphere from the Windscale Piles, two nuclear reactors at Windscale Works, Sellafield, England, during the 1950s was 20 kg. This paper re-examines the assumptions upon which this figure was based and concludes that the value is a realistically conservative estimate of the release, consistent with current radiological protection practice. The mass estimate is derived from a reanalysis of plant data produced at the time. The environmental data on which the initial estimates were based are reconfirmed, and additional support is provided by an interpretation of modelling studies of both the total deposition and milk concentrations resulting from that deposition. Milk-monitoring data from the time are shown to be consistent with the release assumptions used in the dispersion modelling exercise. Finally, the issue of statistical undersampling is addressed using the particle numbers and size distributions produced by the modelling exercise

  1. The Windscale CAGR handling rig - ten years testing

    International Nuclear Information System (INIS)

    It is stated that in order to meet the requirement for Commercial Advanced Gas Cooled Reactor (CAGR) stations to load and discharge fuel whilst maintaining full power it is essential that the fuel stringers, each of which consists of light fuel elements stacked vertically with their associated service and shielding units, should be able to withstand the full range of coolant gas flow forces to which they will be subjected in practice. In order to test this it was decided to construct a full scale fuel stringer test rig which could subject the stringers to good simulation of the coolant conditions in the reactor when refuelling at power. This was built and commissioned at Windscale (UKAEA) in 1976 and has been operating for more than 10 years, and it is thought that the time has been reached to review its performance and record its success in meeting its objectives. The paper describes the rig and the results of fuel stringer testing. The rig has also been used for the testing of other components, and future work with it is also indicated. (U.K.)

  2. After Parker: A review of the Windscale inquiry and subsequent developments

    International Nuclear Information System (INIS)

    For 100 days in 1977, an Inquiry, conducted by Mr. Justice Parker, was held in Great Britain to look at the implications of building a plant at Windscale, on the Cumbrian coast, to reprocess oxide fuel from thermal nuclear reactors. The events, beginning with two public debates before the Inquiry and extending through two debates in the House of Commons after the publication of Mr. Justice Parker's report, and the decision by Parliament, on 15 May 1978 to proceed with the thermal oxide reprocessing plant (THORP) are briefly reviewed. The attitudes and published opinions of the organizations opposed to the plant construction, to the whole evaluation process are discussed

  3. A dose reconstruction case study - the retrospective assessment of neutron dose for workers on the Windscale Piles at Sellafield

    International Nuclear Information System (INIS)

    The Windscale Piles were air-cooled reactors which started operation in 1951 to irradiate natural uranium fuel elements. It is now nearly 40 years since the Windscale Piles ceased operation after a fire during the release of Wigner energy in Reactor 1 on 10 October 1957. The spotlight returned to the Windscale Piles during the recent childhood leukaemia cases because the two fathers concerned worked there during the 1950s. Operators working on the Piles wore film badges and QFEs, but no suitable personal neutron dosemeter was available at that time and no neutron doses were entered onto dose records. For the purposes of litigation, a major dose reconstruction exercise was carried out to retrospectively assess the likely neutron doses received by the two individuals. The paper describes the main steps and processes required to carry out the reconstruction exercise. Within the overall exercise, two technical aspects required particular attention. Firstly, expert interpretation was used to convert contemporary survey measurements into useable data requiring some knowledge of the neutron spectrum and the capabilities of the early neutron instruments. Secondly, it was necessary to model the reactors to predict neutron dose rates for key scenarios identified in the dose reconstruction process for which archive survey information was not located. Finally, the methodology used to convert the survey data and model predictions into neutron doses for the individuals concerned is discussed and contrasted with other potential approaches. (author)

  4. The Windscale Inquiry: the public inquiry system on trial

    International Nuclear Information System (INIS)

    This thesis is concerned with the Windscale Inquiry of 1977 and its effect on the public inquiry system. It focusses both on the major influences of the Windscale Inquiry process, and on the participants, their aims, motivations, expectations and achievements. It provides the most detailed examination of the Inquiry to date and, as a result, uncovers aspects of the process while have not been explored previously. The central questions of the thesis are: Was the outcome of the Windscale Inquiry inevitable or could it have reached different conclusions? and did the Windscale Inquiry demonstrate that the public inquiry system could be used by a government to reach a decision which it favoured? The thesis argues that the outcome of the Windscale Inquiry was almost inevitable. In fact it was found that the Inspector had made up his mind in favour of oxide reprocessing before the Inquiry opened. However, this finding does not express fully the Inquiry's impact, because, as the thesis shows, the Inquiry became a mechanism which forced the nuclear industry and the government to explain, and substantially alter, some parts of their policies. The process of bringing the government and industry to account, did not alter the THORP decision, but it demonstrated that any subsequent inquiries could subject nuclear developments to searching criticism and investigation. Indeed it is suggested that the Windscale Inquiry made it impossible for subsequent Governments to proceed with nuclear expansion without subjecting them to the public inquiry process. Part I of the thesis examines the history and structure of the public Inquiry system and the relevant aspects of planning law. Part II describes the history of reprocessing and the themes which led to the public inquiry being established. Part III forms the most detailed part of the thesis and examines the Windscale Inquiry process focussing on the participants and the issues involved. (author)

  5. AGR-1 Thermocouple Data Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jeff Einerson

    2012-05-01

    This report documents an effort to analyze measured and simulated data obtained in the Advanced Gas Reactor (AGR) fuel irradiation test program conducted in the INL's Advanced Test Reactor (ATR) to support the Next Generation Nuclear Plant (NGNP) R&D program. The work follows up on a previous study (Pham and Einerson, 2010), in which statistical analysis methods were applied for AGR-1 thermocouple data qualification. The present work exercises the idea that, while recognizing uncertainties inherent in physics and thermal simulations of the AGR-1 test, results of the numerical simulations can be used in combination with the statistical analysis methods to further improve qualification of measured data. Additionally, the combined analysis of measured and simulation data can generate insights about simulation model uncertainty that can be useful for model improvement. This report also describes an experimental control procedure to maintain fuel target temperature in the future AGR tests using regression relationships that include simulation results. The report is organized into four chapters. Chapter 1 introduces the AGR Fuel Development and Qualification program, AGR-1 test configuration and test procedure, overview of AGR-1 measured data, and overview of physics and thermal simulation, including modeling assumptions and uncertainties. A brief summary of statistical analysis methods developed in (Pham and Einerson 2010) for AGR-1 measured data qualification within NGNP Data Management and Analysis System (NDMAS) is also included for completeness. Chapters 2-3 describe and discuss cases, in which the combined use of experimental and simulation data is realized. A set of issues associated with measurement and modeling uncertainties resulted from the combined analysis are identified. This includes demonstration that such a combined analysis led to important insights for reducing uncertainty in presentation of AGR-1 measured data (Chapter 2) and interpretation of

  6. Windscale: a case history in the political art of muddling through

    International Nuclear Information System (INIS)

    This chapter concentrates mainly upon those factors which preceded and eventually led to the Windscale Inquiry (into the BNFL proposal to construct a plant to reprocess spent nuclear fuel from reactors using oxide fuels). This will help to illustrate some of the many covert themes which permeated the Inquiry as an exercise in conflict-management, and hopefully should assist in the understanding of the limitations of this form of decision-making process. The chapter will conclude with a comment upon the role of the Inquiry in the wider political context of the British energy 'debate' and upon the likely implications of the Inquiry for future decision-making ventures on similar technological developments. (author)

  7. AGR-1, AGR-2 and AGR-3/4 Dimensional Change Data Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Herberger, Sarah E. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-02-01

    A series of Advanced Gas Reactor (AGR) experiments have been completed in the Advanced Test Reactor at Idaho National Laboratory in support of qualification and development of tristructural isotropic fuel. Each AGR test consists of multiple independently controlled and monitored capsules containing fuel compacts placed in a graphite cylinder. These capsules are instrumented with thermocouples embedded in the graphite, enabling temperature control. The fuel compacts are composed of fuel particles surrounded by a graphitic A3 matrix material. Dimensional change in AGR fuel compacts is vital because the swelling or shrinkage affects the size of the gas gaps that are used to control temperatures. Analysis of dimensional change in the AGR fuel compacts is needed to establish the variables directly relating to compact shrinkage. The variables initially identified for consideration were matrix density, compact density, fuel packing fraction, uranium loading, fuel particle diameter, cumulative fast neutron fluence, and volume average time average fuel temperature. In addition to the data available from the AGR experiments, the analysis included specimens formed from the same A3 matrix material used in Advanced Graphite Creep (AGC) experiments, which provide graphite creep data during irradiation for design and licensing purposes. The primary purpose of including the AGC specimens was to encompass dimensional behavior at zero packing fraction, zero uranium loading, and zero particle diameter. All possible combinations of first-order variable regressions were considered in the analysis. The study focused on identifying the best regression models for percent change in diameter, length, and volume. Bootstrap analysis was used to ensure the resulting regression models were robust and well-performing. The variables identified as very significant in predicting change in one or more dimensions (diameter, length, and volume) are volume average time average temperature, fast fluence

  8. AGR core safety assessment methodologies

    International Nuclear Information System (INIS)

    To demonstrate the safety of its gas-cooled graphite-moderated AGR reactors, nuclear safety assessments of the cores are based upon a methodology which demonstrates no component failures, geometrical stability of the structure and material properties bounded by a database. All AGRs continue to meet these three criteria. However, predictions of future core behaviour indicate that the safety case methodology will eventually need to be modified to deal with new phenomena. A new approach to the safety assessment of the cores is currently under development, which can take account of these factors while at the same time providing the same level of protection for the cores. This approach will be based on the functionality of the core: unhindered movement of control rods, continued adequate cooling of the fuel and the core, continued ability to charge and discharge fuel. (author). 5 figs

  9. Determination of nuclear heating thermocoupled fuel pins in AGR instrumented stringers

    International Nuclear Information System (INIS)

    Mismatches in linear rating between standard and thermocoupled fuel pins in instrumented CAGR fuel clusters are minimised at start-of-life by choice of enrichment, but change with irradiation due to differential plutonium production and uranium depletion. Calculation of mismatches are assessed by comparison with gamma-scanning measurements on a Windscale AGR Mk 5 cluster. It is concluded that start-of-life calculations of relative linear ratings are accurate to +- 2% (1sigma), and that changes with irradiation are predicted to +- 25% (1sigma). (author)

  10. Scottish Nuclear Limited: the AGR - past, present and future

    International Nuclear Information System (INIS)

    This article reviews the historical development of the AGR (advanced gas-cooled reactor) in Scotland from its inception to its current successfully established position. It examines where the AGRs will go in the future and concludes with the strategic role of the existing and new plant in the market-led electricity supply industry. (Author)

  11. AGR-1 Data Qualification Report

    Energy Technology Data Exchange (ETDEWEB)

    Michael Abbott

    2010-03-01

    ABSTRACT Projects for the very high temperature reactor (VHTR) Technology Development Office (TDO) program provide data in support of Nuclear Regulatory Commission licensing of the VHTR. Fuel and materials to be used in the reactor are tested and characterized to quantify performance in high temperature and high fluence environments. The VHTR program has established the NGNP Data Management and Analysis System (NDMAS) to ensure that VHTR data are (1) qualified for use, (2) stored in a readily accessible electronic form, and (3) analyzed to extract useful results. This document focuses on the first NDMAS objective. It describes the data streams associated with the first Advanced Gas Reactor experiment (AGR-1), the processing of these data within NDMAS, and reports the qualification status of the data. Data qualification activities within NDMAS for specific types of data are determined by the data qualification category assigned by the data generator. They include: (1) capture testing, to confirm that the data stored within NDMAS are identical to the raw data supplied, (2) accuracy testing, to confirm that the data are an accurate representation of the system or object being measured, and (3) documentation that the data were collected under an NQA-1 or equivalent quality assurance program. The NDMAS database processing and qualification status of the following five data streams is reported in this document: 1. Fuel fabrication data. All data have been processed into the NDMAS database and qualified (1,819 records). 2. Fuel irradiation data. Data from all 13 AGR-1 reactor cycles have been processed into the NDMAS database and tested. Of these, 85% have been qualified and 15% have failed NDMAS accuracy testing. 3. FPMS data. Reprocessed (January 2010) data from all 13 AGR-1 reactor cycles have been processed into the database and capture tested. Final qualification of these data will be recorded after QA approval of an Engineering Calculations and Analysis Report

  12. Safety testing of AGR-2 UO2 compacts 3-3-2 and 3-4-2

    Energy Technology Data Exchange (ETDEWEB)

    Hunn, John D. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Morris, Robert Noel [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Baldwin, Charles A. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Montgomery, Fred C. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

    2015-09-01

    Post-irradiation examination (PIE) is in progress on tristructural-isotropic (TRISO) coated-particle fuel compacts from the Advanced Gas Reactor (AGR) Fuel Development and Qualification Program second irradiation experiment (AGR-2) [Collin 2014]. The AGR-2 PIE will build upon new information and understanding acquired throughout the recently-concluded six-year AGR-1 PIE campaign [Demkowicz et al. 2015] and establish a database for the different AGR-2 fuel designs.

  13. Safety testing of AGR-2 UO2 compacts 3-3-2 and 3-4-2

    International Nuclear Information System (INIS)

    Post-irradiation examination (PIE) is in progress on tristructural-isotropic (TRISO) coated-particle fuel compacts from the Advanced Gas Reactor (AGR) Fuel Development and Qualification Program second irradiation experiment (AGR-2) [Collin 2014]. The AGR-2 PIE will build upon new information and understanding acquired throughout the recently-concluded six-year AGR-1 PIE campaign [Demkowicz et al. 2015] and establish a database for the different AGR-2 fuel designs.

  14. Consequences of Windscale accident (October 1957) and study of the validity of the Sutton's mathematical model of atmospheric diffusion (1960)

    International Nuclear Information System (INIS)

    The reactor accident that happens at the number 1 pile of Windscale in 1957 was followed by a discharge of radioactive products into the atmosphere from the 1.X.1957 at 4.30 PM to the 12.X.1957 at 3.10 PM. On october the 11th it was possible to say that there was no more risk either of external irradiation or inhalation. But in adopting a M.A.C. of 0,1 μcurie of iodine 131 per litre of milk, the Authority had to control the milk delivery till november 23rd on a 500 km2 area. On the other hand, this exceptional accident permit to verify that Sutton's atmospheric diffusion model could give an easy means to foresee, with a sufficient approximation, the consequences of a dispersion of radioactive products into the atmosphere. (author)

  15. AgrAbility Project

    Science.gov (United States)

    ... hours ago AgrAbility's 25 Years, 25 Stories Rosendo Ramirez is a farmworker in California, a job that ... Rosendo continues to work. www.agrability.org/25years/ramirez/ ... See More See Less Rosendo Ramirez: Ingenuity, perseverance, ...

  16. AGR-1 Safety Test Predictions using the PARFUME code

    Energy Technology Data Exchange (ETDEWEB)

    Blaise Collin

    2012-05-01

    The PARFUME modeling code was used to predict failure probability of TRISO-coated fuel particles and diffusion of fission products through these particles during safety tests following the first irradiation test of the Advanced Gas Reactor program (AGR-1). These calculations support the AGR-1 Safety Testing Experiment, which is part of the PIE effort on AGR-1. Modeling of the AGR-1 Safety Test Predictions includes a 620-day irradiation followed by a 300-hour heat-up phase of selected AGR-1 compacts. Results include fuel failure probability, palladium penetration, and fractional release of fission products. Results show that no particle failure is predicted during irradiation or heat-up, and that fractional release of fission products is limited during irradiation but that it significantly increases during heat-up.

  17. Uncertainty Quantification of Calculated Temperatures for the AGR-1 Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Binh T. Pham; Jeffrey J. Einerson; Grant L. Hawkes

    2013-03-01

    This report documents an effort to quantify the uncertainty of the calculated temperature data for the first Advanced Gas Reactor (AGR-1) fuel irradiation experiment conducted in the INL’s Advanced Test Reactor (ATR) in support of the Next Generation Nuclear Plant (NGNP) R&D program. Recognizing uncertainties inherent in physics and thermal simulations of the AGR-1 test, the results of the numerical simulations can be used in combination with the statistical analysis methods to improve qualification of measured data. Additionally, the temperature simulation data for AGR tests can be used for validation of the fuel transport and fuel performance simulation models. The crucial roles of the calculated fuel temperatures in ensuring achievement of the AGR experimental program objectives require accurate determination of the model temperature uncertainties. The report is organized into three chapters. Chapter 1 introduces the AGR Fuel Development and Qualification program and provides overviews of AGR-1 measured data, AGR-1 test configuration and test procedure, and thermal simulation. Chapters 2 describes the uncertainty quantification procedure for temperature simulation data of the AGR-1 experiment, namely, (i) identify and quantify uncertainty sources; (ii) perform sensitivity analysis for several thermal test conditions; (iii) use uncertainty propagation to quantify overall response temperature uncertainty. A set of issues associated with modeling uncertainties resulting from the expert assessments are identified. This also includes the experimental design to estimate the main effects and interactions of the important thermal model parameters. Chapter 3 presents the overall uncertainty results for the six AGR-1 capsules. This includes uncertainties for the daily volume-average and peak fuel temperatures, daily average temperatures at TC locations, and time-average volume-average and time-average peak fuel temperatures.

  18. The UK Windscale inquiry - towards the end of the nuclear debate

    International Nuclear Information System (INIS)

    In June, 1977 the Honourable Mr Justice Parker opened the Windscale Inquiry into an application by British Nuclear Fuels Limited for planning permission for 'a plant for reprocessing irradiated oxide nuclear fuels and support site services' at their Windscale and Calder works in Cumbria. The Report of the Inquiry, concluding in favour of the development, was presented in January, 1978. The consequent legislation authorising the construction of the plant was passed in the House of Commons in May, 1978 by 224 votes to 80. The author looks at the debate surrounding the enquiry

  19. AGR-2 AND AGR-3/4 RELEASE-TO-BIRTH RATIO DATA ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Binh T; Einerson, Jeffrey J; Scates, Dawn M; Maki, John T; Petti, David A

    2014-09-01

    A series of Advanced Gas Reactor (AGR) irradiation tests is being conducted in the Advanced Test Reactor at Idaho National Laboratory in support of development and qualification of tristructural isotropic (TRISO) low enriched fuel used in the High Temperature Gas-cooled Reactor (HTGR). Each AGR test consists of multiple independently controlled and monitored capsules containing fuel compacts placed in a graphite cylinder shrouded by a steel shell. These capsules are instrumented with thermocouples embedded in the graphite enabling temperature control. AGR configuration and irradiation conditions are based on prismatic HTGR technology distinguished primarily by the use of helium coolant, a low-power-density ceramic core capable of withstanding very high temperatures, and TRISO coated particle fuel. Thus, these tests provide valuable irradiation performance data to support fuel process development, qualify fuel for normal operating conditions, and support development and validation of fuel performance and fission product transport models and codes. The release-rate-to-birth-rate ratio (R/B) for each of fission product isotopes (i.e., krypton and xenon) is calculated from release rates in the sweep gas flow measured by the germanium detectors used in the AGR Fission Product Monitoring (FPM) System installed downstream from each irradiated capsule. Birth rates are calculated based on the fission power in the experiment and fission product generation models. Thus, this R/B is a measure of the ability of fuel kernel, particle coating layers, and compact matrix to retain fission gas atoms preventing their release into the sweep gas flow, especially in the event of particle coating failures that occurred during AGR-2 and AGR-3/4 irradiations. The major factors that govern gaseous radioactive decay, diffusion, and release processes are found to be material diffusion coefficient, temperature, and isotopic decay constant. For each of all AGR capsules, ABAQUS-based three

  20. AGR-2 Data Qualification Report for ATR Cycle 154B

    Energy Technology Data Exchange (ETDEWEB)

    Binh Pham; Jeff Einerson

    2014-01-01

    This report provides the data qualification status of Advanced Gas Reactor-2 (AGR-2) fuel irradiation experimental data from Advanced Test Reactor (ATR) Cycle 154B as recorded in the Nuclear Data Management and Analysis System (NDMAS). This is the last cycle of AGR-2 irradiation, as the test train was pulled from the ATR core during the outage portion of ATR Cycle 155A. The AGR-2 data streams addressed in this report include thermocouple (TC) temperatures, sweep gas data (flow rates including new Fission Product Monitoring (FPM) downstream flows from Fission Product Monitoring System (FPMS) detectors, pressure, and moisture content), and FPMS data (release rates and release-to-birth rate ratios [R/Bs]) for each of the six capsules in the AGR-2 experiment. The final data qualification status for these data streams is determined by a Data Review Committee (DRC) comprised of AGR technical leads, Sitewide Quality Assurance (QA), and NDMAS analysts. The Data Review Committee reviewed the data acquisition process, considered whether the data met the requirements for data collection as specified in QA-approved Very High Temperature Reactor (VHTR) data collection plans, examined the results of NDMAS data testing and statistical analyses, and confirmed the qualification status of the data as given in this report.

  1. AGR-1 Data Qualification Interim Report

    Energy Technology Data Exchange (ETDEWEB)

    Machael Abbott

    2009-08-01

    Projects for the very-high-temperature reactor (VHTR) program provide data in support of Nuclear Regulatory Commission licensing of the VHTR. Fuel and materials to be used in the reactor are tested and characterized to quantify performance in high temperature and high fluence environments. The VHTR Program has established the NGNP Data Management and Analysis System (NDMAS) to ensure that VHTR data are (1) qualified for use, (2) stored in a readily accessible electronic form, and (3) analyzed to extract useful results. This document focuses on the first NDMAS objective. It describes the data streams associated with the first Advanced Gas Reactor (AGR-1) experiment, the processing of these data within NDMAS, and reports the interim FY09 qualification status of the AGR-1 data to date. Data qualification activities within NDMAS for specific types of data are determined by the data qualification category, which is assigned by the data generator, and include: (1) capture testing, to confirm that the data stored within NDMAS are identical to the raw data supplied, (2) accuracy testing, to confirm that the data are an accurate representation of the system or object being measured, and (3) documentation that the data were collected under an NQA-1 or equivalent QA program. The interim qualification status of the following four data streams is reported in this document: (1) fuel fabrication data, (2) fuel irradiation data, (3) fission product monitoring system (FPMS) data, and (4) Advanced Test Reactor (ATR) operating conditions data. A final report giving the NDMAS qualification status of all AGR-1 data (including cycle 145A) is planned for February 2010.

  2. A comparison of the observed and the expected cancers of the haematopoietic and lymphatic systems among workers at Windscale

    International Nuclear Information System (INIS)

    Data are given about the cases of cancers of the haematopoietic and lymphatic systems among workers at Windscale Works, BNFL during the period 1950 to 1974. The number of cancers of these types expected to occur in the working population at Windscale has been estimated for the same period. For none of these types is the observed number of cancers significantly different at the 95% confidence level from that expected. (author)

  3. Experience with a servo-hydraulic mechanical testing machine installed in a new shielded active facility at Windscale Nuclear Power Development Laboratories

    International Nuclear Information System (INIS)

    An Instron model 1273 servo-hydraulic machine has been installed within a lead-shielded cell at Windscale in order to provide a facility capable of performing a wide range of mechanical tests on nuclear reactor structural materials and fuel assembly components. This particular type of machine was chosen because it has design features associated with the load frame, location of the actuator and adjustment and clamping of the cross-head that are especially well suited to remote operation within a shielded cell. The design of the testing facility is described and the programmes of work that have been completed over the past 11/2 years of operation are reviewed. (author)

  4. Chemical cleaning of UK AGR boilers

    International Nuclear Information System (INIS)

    For a number of years, the waterside pressure drops across the advanced gas-cooled reactor (AGR) pod boilers have been increasing. The pressure drop increases have accelerated with time, which is the converse behaviour to that expected for rippled magnetite formation (rapid initial increase slowing down with time). Nonetheless, magnetite deposition remains the most likely cause for the increasing boiler resistances. A number of potential countermeasures have been considered in response to the boiler pressure drop increases. However, there was no detectable reduction in the rate of pressure drop increase. Chemical cleaning was therefore considered and a project to substantiate and then implement chemical cleaning was initiated. (authors)

  5. AGR-1 Post Irradiation Examination Final Report

    International Nuclear Information System (INIS)

    The post-irradiation examination (PIE) of the Advanced Gas Reactor (AGR)-1 experiment was a multi-year, collaborative effort between Idaho National Laboratory (INL) and Oak Ridge National Laboratory (ORNL) to study the performance of UCO (uranium carbide, uranium oxide) tristructural isotropic (TRISO) coated particle fuel fabricated in the U.S. and irradiated at the Advanced Test Reactor at INL to a peak burnup of 19.6% fissions per initial metal atom. This work involved a broad array of experiments and analyses to evaluate the level of fission product retention by the fuel particles and compacts (both during irradiation and during post-irradiation heating tests to simulate reactor accident conditions), investigate the kernel and coating layer morphology evolution and the causes of coating failure, and explore the migration of fission products through the coating layers. The results have generally confirmed the excellent performance of the AGR-1 fuel, first indicated during the irradiation by the observation of zero TRISO coated particle failures out of 298,000 particles in the experiment. Overall release of fission products was determined by PIE to have been relatively low during the irradiation. A significant finding was the extremely low levels of cesium released through intact coatings. This was true both during the irradiation and during post-irradiation heating tests to temperatures as high as 1800°C. Post-irradiation safety test fuel performance was generally excellent. Silver release from the particles and compacts during irradiation was often very high. Extensive microanalysis of fuel particles was performed after irradiation and after high-temperature safety testing. The results of particle microanalysis indicate that the UCO fuel is effective at controlling the oxygen partial pressure within the particle and limiting kernel migration. Post-irradiation examination has provided the final body of data that speaks to the quality of the AGR-1 fuel, building

  6. AGR-1 Post Irradiation Examination Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Demkowicz, Paul Andrew [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-08-01

    The post-irradiation examination (PIE) of the Advanced Gas Reactor (AGR)-1 experiment was a multi-year, collaborative effort between Idaho National Laboratory (INL) and Oak Ridge National Laboratory (ORNL) to study the performance of UCO (uranium carbide, uranium oxide) tristructural isotropic (TRISO) coated particle fuel fabricated in the U.S. and irradiated at the Advanced Test Reactor at INL to a peak burnup of 19.6% fissions per initial metal atom. This work involved a broad array of experiments and analyses to evaluate the level of fission product retention by the fuel particles and compacts (both during irradiation and during post-irradiation heating tests to simulate reactor accident conditions), investigate the kernel and coating layer morphology evolution and the causes of coating failure, and explore the migration of fission products through the coating layers. The results have generally confirmed the excellent performance of the AGR-1 fuel, first indicated during the irradiation by the observation of zero TRISO coated particle failures out of 298,000 particles in the experiment. Overall release of fission products was determined by PIE to have been relatively low during the irradiation. A significant finding was the extremely low levels of cesium released through intact coatings. This was true both during the irradiation and during post-irradiation heating tests to temperatures as high as 1800°C. Post-irradiation safety test fuel performance was generally excellent. Silver release from the particles and compacts during irradiation was often very high. Extensive microanalysis of fuel particles was performed after irradiation and after high-temperature safety testing. The results of particle microanalysis indicate that the UCO fuel is effective at controlling the oxygen partial pressure within the particle and limiting kernel migration. Post-irradiation examination has provided the final body of data that speaks to the quality of the AGR-1 fuel, building

  7. Dimethylamine as a replacement for ammonia dosing in the secondary circuit of an advanced gas-cooled reactor (AGR) power station

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, Chris; Mitchell, Malcolm S. [EDF Energy, Hartlepool Power Station, Hartlepool (United Kingdom); Bull, Andrew E.A.; Quirk, Graham P.; Rudge, Andy [EDF Energy Nuclear Generation, Barnwood, Gloucester (United Kingdom). Central Technical Organisation; Woolsey, Ian S.

    2012-06-15

    Increasing flow resistance observed over recent years within the helical once-through boilers in the four advanced gas-cooled reactors at Hartlepool and Heysham 1 Power Stations have reduced boiler performance, resulting in reductions in feedwater flow, steam temperatures, and power output and in the need to carry out periodic chemical cleaning. The root cause is believed to be the development of magnetite deposits with high flow impedance in the 9Cr1Mo evaporator section of the boiler tubing. To prevent continued increases in boiler flow resistance, dimethylamine is being trialled, in one of the four affected units, as a replacement to the conventional ammonia dosing. Dimethylamine increases the pH at temperature around the secondary circuit and, based on full scale boiler rig simulations, is expected to reduce iron transport and prevent flow resistance increases within the evaporator section of the boiler. The dimethylamine plant trial commenced in January 2011 and is ongoing. The feedwater concentration of dimethylamine has been increased progressively towards a final target value of 900 {mu}g . kg{sup -1} and its effect on iron transport and boiler pressure loss is being closely monitored. The high steam temperature (> 500 C) of the secondary circuit leads to some decomposition of dimethylamine, which is being carefully monitored at various locations around the circuit. The decomposition products identified with dimethylamine dosing include ammonia, methylamine, formic acid, carbon dioxide and, as yet, unidentified neutral organic species. The effect of dimethylamine dosing on iron transport and boiler pressure drops and its decomposition behaviour around the secondary circuit during the plant trial will be presented in this paper. (orig.)

  8. Radiological and medical consequences of the Windscale fire of october 1957

    International Nuclear Information System (INIS)

    A fire in a Windscale pile released a few percent of the radioactive inventory before being extinguished with water on 11 October 1957. About 20 KCi of radio iodine dominated the potential exposure pathways to man. Environmental surveys resulted in 3000 tons of milk being poured to sea from an area extending up to 40 km. The restrictions lasted for six weeks in some areas. Compensation was paid. Fourteen employees were exposed to external radiation above the UK occupational limit of that time, 3R in 3 months, the maximum being 5R. Clinical effects were neither expected nor seen at this level of exposure. The health of approximately 500 workers concerned has been followed and is good, as is the health of the 2500 employed at the time. Health data is given for some 14,000 employees over a period of forty years. The employees and public living nearby, downwind, had thyroid doses up to 20 mSv and children up to 40 mSv mostly from inhalation. Where local milk was consumed, the children thyroid dose was about 160 mSv. A study of thyroid cancer in Cumbria, population 500,000, up to 1986 has shown that the incidence of thyroid cancer is lower than the national average. The incidence around Windscale is very low. Obstetric studies showed that in the nearby village of Seascale, children have fared better than average. The one recognised problem is 9 cases of leukaemia and lymphoma in the young of the Seascale area over 40 years. It does not seem to be connected with the Windscale fire of 1957, nor with radioactivity in the environment. National studies have been set up to seek an explanation. The predicted risks to populations in Cumbria, UK, and Europe are given

  9. AGR design for heysham II and Torness

    International Nuclear Information System (INIS)

    The background to the decision to build two AGR stations at Heysham and Torness is reviewed. The stations will each have twin 660MW(c) reactors based on the design of these at Hinkley Point B and Hunterston B, but including design changes introduced to meet enhanced safety requirements. The main features of the new design are described. Changes include: the provision of greater diversity in the shut-down and post-trip cooling systems; increased segregation of post-trip cooling and protection systems against fires and other hazards; measures for withstanding a major earthquake and extreme winds; greater provision for inservice inspection. The station layout is illustrated. Some generating costs are shown in comparison with a PWR and a coal-fired unit. (U.K.)

  10. The Windscale inquiry and its impact on the national nuclear programme

    International Nuclear Information System (INIS)

    This lecture by the Director of Information Services, British Nuclear Fuels Ltd., endeavours to convey something of the flavour of the recent Windscale Inquiry that lasted for 100 days and the results of which encompassed about four million words. It is stated that in at least the short term nuclear power in this country will only expand at a rate that is acceptable to the general public, largely as influenced by members of parliament and the media, including the press. It probably will not expand at a rate acceptable to scientists or deemed necessary by them. The pressure that led to the inquiry will not lessen because the inquiry is over; if anything it will increase. Nevertheless, eventually the nuclear power industry must win and the public will be forced to learn to live with it since the alternative, a society short of energy, is intolerable. Unless the industry has a reasonably consistent work load and a reasonably consistent demand for its products it will become moribund. Comparisons are made with the history of the coal industry. It is believed that one of the main lessons to be learnt form the Windscale Inquiry is that the Nuclear Power Industry's immediate future lies largely in its own hands. An outline is included of the past and probable future work of British Nuclear Fuels Ltd. with emphasis on the reprocessing of irradiated oxide fuel. (author)

  11. Consequences of Windscale accident (October 1957) and study of the validity of the Sutton's mathematical model of atmospheric diffusion (1960); Etude des consequences de l'accident de Windscale (Octobre 1957) et de la validite du modele mathematique de diffusion atmospherique de Sutton (1960)

    Energy Technology Data Exchange (ETDEWEB)

    Doury, A. [Commissariat a l' Energie Atomique (S.C.R.G.R.) Saclay (France).Centre d' Etudes Nucleaires; Martin, J.J. [Electricite de France (EDF)(S.L.P.R.), 37 - Chinon (France)

    1960-07-01

    The reactor accident that happens at the number 1 pile of Windscale in 1957 was followed by a discharge of radioactive products into the atmosphere from the 1.X.1957 at 4.30 PM to the 12.X.1957 at 3.10 PM. On october the 11{sup th} it was possible to say that there was no more risk either of external irradiation or inhalation. But in adopting a M.A.C. of 0,1 {mu}curie of iodine 131 per litre of milk, the Authority had to control the milk delivery till november 23{sup rd} on a 500 km{sup 2} area. On the other hand, this exceptional accident permit to verify that Sutton's atmospheric diffusion model could give an easy means to foresee, with a sufficient approximation, the consequences of a dispersion of radioactive products into the atmosphere. (author) [French] L'accident survenu a la pile numero 1 de Windscale en 1957 a entraine l'emission de matieres radioactives dans l'atmosphere du 10 octobre a 16h30 au 12 octobre a 15h10. Le 11 octobre, on pouvait dire qu'il n'y avait plus de risque d'irradiation externe ni de danger par inhalation. Mais en adoptant une C.M.A. de 0,1 {mu}curie d'iode 131 par litre de lait, les autorites ont du reglementer la consommation du lait jusqu'au 23 novembre sur une etendue d'environ 500 km{sup 2}. D'autre part, cet accident exceptionnel a permis de verifier que le modele de diffusion atmospherique de Sutton pouvait fournir un moyen commode de prevoir avec une approximation suffisante les consequences d'une dispersion de produits radioactifs dans l'atmosphere. (auteur)

  12. Advances in AGR fuel fabrication - now and the future

    International Nuclear Information System (INIS)

    To date, over 3 million AGR fuel pins have been manufactured at Springfields for the UK AGR programme. During this time, AGR fuel design and manufacture has developed and evolved in response to the needs of the reactor operators to enhance fuel reliability and performance. More recently, major advances have been made in the systems and organisational culture which support fuel manufacture at Fuel Division. The introduction of MRP II in 1989 into Fuel Division enabled significant reductions in stock and work-in-progress, together with reductions in manufacturing lead times. Other successful initiatives introduced into Fuel Division have been Just-in-Time (JIT) and AST (Additional Skills Training) which have built on the success of MRP II. All of these initiatives are evidence of Fuel Division's ''Total Quality'' approach to fabricating fuel. Fuel Division is currently in the final stages of commissioning the New Oxide Fuels Complex (NOFC) where both AGR and PWR fuel will be manufactured to the highest standards of quality, safety and environmental protection. NOFC is a totally integrated plant which represents a Pound 200M investment, demonstrating Fuel Division's commitment to building on its 40+ years of fuel fabrication experience and ensuring secure supply of fuel to its customers for years to come. (author)

  13. AGR-2 IRRADIATION TEST FINAL AS-RUN REPORT

    Energy Technology Data Exchange (ETDEWEB)

    Blaise, Collin

    2014-07-01

    This document presents the as-run analysis of the AGR-2 irradiation experiment. AGR-2 is the second of the planned irradiations for the Advanced Gas Reactor (AGR) Fuel Development and Qualification Program. Funding for this program is provided by the U.S. Department of Energy as part of the Very High Temperature Reactor (VHTR) Technical Development Office (TDO) program. The objectives of the AGR-2 experiment are to: (a) Irradiate UCO (uranium oxycarbide) and UO2 (uranium dioxide) fuel produced in a large coater. Fuel attributes are based on results obtained from the AGR-1 test and other project activities. (b) Provide irradiated fuel samples for post-irradiation experiment (PIE) and safety testing. (c) Support the development of an understanding of the relationship between fuel fabrication processes, fuel product properties, and irradiation performance. The primary objective of the test was to irradiate both UCO and UO2 TRISO (tri-structural isotropic) fuel produced from prototypic scale equipment to obtain normal operation and accident condition fuel performance data. The UCO compacts were subjected to a range of burnups and temperatures typical of anticipated prismatic reactor service conditions in three capsules. The test train also includes compacts containing UO2 particles produced independently by the United States, South Africa, and France in three separate capsules. The range of burnups and temperatures in these capsules were typical of anticipated pebble bed reactor service conditions. The results discussed in this report pertain only to U.S. produced fuel. In order to achieve the test objectives, the AGR-2 experiment was irradiated in the B-12 position of the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) for a total irradiation duration of 559.2 effective full power days (EFPD). Irradiation began on June 22, 2010, and ended on October 16, 2013, spanning 12 ATR power cycles and approximately three and a half calendar years. The test

  14. AGR-2 Safety Test Predictions Using the PARFUME Code

    Energy Technology Data Exchange (ETDEWEB)

    Blaise Collin

    2014-09-01

    This report documents calculations performed to predict failure probability of TRISO-coated fuel particles and diffusion of fission products through these particles during safety tests following the second irradiation test of the Advanced Gas Reactor program (AGR-2). The calculations include the modeling of the AGR-2 irradiation that occurred from June 2010 to October 2013 in the Advanced Test Reactor (ATR) and the modeling of a safety testing phase to support safety tests planned at Oak Ridge National Laboratory and at Idaho National Laboratory (INL) for a selection of AGR-2 compacts. The heat-up of AGR-2 compacts is a critical component of the AGR-2 fuel performance evaluation, and its objectives are to identify the effect of accident test temperature, burnup, and irradiation temperature on the performance of the fuel at elevated temperature. Safety testing of compacts will be followed by detailed examinations of the fuel particles to further evaluate fission product retention and behavior of the kernel and coatings. The modeling was performed using the particle fuel model computer code PARFUME developed at INL. PARFUME is an advanced gas-cooled reactor fuel performance modeling and analysis code (Miller 2009). It has been developed as an integrated mechanistic code that evaluates the thermal, mechanical, and physico-chemical behavior of fuel particles during irradiation to determine the failure probability of a population of fuel particles given the particle-to-particle statistical variations in physical dimensions and material properties that arise from the fuel fabrication process, accounting for all viable mechanisms that can lead to particle failure. The code also determines the diffusion of fission products from the fuel through the particle coating layers, and through the fuel matrix to the coolant boundary. The subsequent release of fission products is calculated at the compact level (release of fission products from the compact). PARFUME calculates the

  15. Design and development of steam generators for the AGR power stations at Heysham II/Torness

    International Nuclear Information System (INIS)

    The current AGR steam generator design is a development of the successful once-through units supplied for the Oldbury Magnox and Hinkley/Hunterston AGR power stations. These units have demonstrated proven control and reliability in service. In this paper the factors which have dictated the design and layout of the latest AGR steam generators are described and reference made to the latest high temperature design techniques that have been employed. Details of development work to support the design and establish the performance characteristics over the range of plant operating conditions are also given. To comply with current UK safety standards, the AGR steam generators and associated plant are designed to accommodate seismic loadings. In addition, provision is made for an independent heat removal system for post reactor trip operations. (author)

  16. The leakage of radioactive liquor into the ground, British Nuclear Fuels Ltd., Windscale, 15 March 1979

    International Nuclear Information System (INIS)

    On 15 March 1979 radioactive liquor of recent origin was confirmed to be present in the ground adjacent to the Buffer Storage Plant Building B212 at the Windscale and Calder Works in Cumbria of British Nuclear Fuels Ltd. BNFL's initial investigations to identify the source of this leakage were closely followed by an investigation carried out by HM Nuclear Installations Inspectorate into how control of the radioactive liquor came to be lost and whether there had been any breaches of licence conditions or of the requirements of the Health and Safety at Work etc Act 1974. This report presents the findings of these investigations and concludes by outlining the actions taken and the requirements placed on British Nuclear Fuels Ltd. (author)

  17. Engineering design of the Windscale advanced gas-cooled reactor decommissioning machine and robotic manipulator

    International Nuclear Information System (INIS)

    The paper reviews the background to the Decommissioning System and the stages through which it was developed before arriving at the final concept. Included is the steel materials radioactive inventory which gives radioactivity and weight of steel materials to be size reduced and handled by the System. A detailed description of the decommissioning machine and handling system is given. It describes how the problem of radiation shine where manipulator platform service lines pass through the floor shield was overcome by careful design. Key dates of important stages in the supply of the system are included. (author)

  18. Emission of fission products and other activities during the accident to Windscale Pile no. 1 in October 1957

    International Nuclear Information System (INIS)

    Information on the release of activity from Windscale during the accident of October 1957 is reviewed, and some previously unpublished data are given. The activities of 131I released to atmosphere, retained on the pile filters and washed out of the pile are compared with the activity in the channels involved in the fire. The information on the physical form of the released activity is summarised. (author)

  19. DETERMINATION OF THE AGR-1 CAPSULE TO FPMS SPECTROMETER TRANSPORT VOLUMES FROM LEADOUT FLOW TEST DATA

    International Nuclear Information System (INIS)

    The AGR-1 experiment is a fueled multiple-capsule irradiation experiment being conducted in the Advanced Test Reactor (ATR) in support of the Advanced Gas Reactor (AGR) Fuel Development and Qualification Program. A flow experiment conducted during the AGR-1 irradiation provided data that included the effect of flow rate changes on the decay of a short-lived radionuclide (23Ne). This data has been analyzed to determine the capsule-specific downstream transport volume through which the capsule effluents must pass before arrival at the fission product monitoring system spectrometers. These resultant transport volumes when coupled with capsule outlet flow rates determine the transport times from capsule-to-detector. In this work an analysis protocol is developed and applied in order to determine capsule-specific transport volumes to precisions of better than +/- 7%

  20. AGR-1 Irradiation Test Final As-Run Report

    Energy Technology Data Exchange (ETDEWEB)

    Blaise P. Collin

    2012-06-01

    This document presents the as-run analysis of the AGR-1 irradiation experiment. AGR-1 is the first of eight planned irradiations for the Advanced Gas Reactor (AGR) Fuel Development and Qualification Program. Funding for this program is provided by the US Department of Energy (DOE) as part of the Next-Generation Nuclear Plant (NGNP) project. The objectives of the AGR-1 experiment are: 1. To gain experience with multi-capsule test train design, fabrication, and operation with the intent to reduce the probability of capsule or test train failure in subsequent irradiation tests. 2. To irradiate fuel produced in conjunction with the AGR fuel process development effort. 3. To provide data that will support the development of an understanding of the relationship between fuel fabrication processes, fuel product properties, and irradiation performance. In order to achieve the test objectives, the AGR-1 experiment was irradiated in the B-10 position of the Advanced Test Reactor (ATR) at the Idaho National Laboratory (INL) for a total duration of 620 effective full power days of irradiation. Irradiation began on December 24, 2006 and ended on November 6, 2009 spanning 13 ATR cycles and approximately three calendar years. The test contained six independently controlled and monitored capsules. Each capsule contained 12 compacts of a single type, or variant, of the AGR coated fuel. No fuel particles failed during the AGR-1 irradiation. Final burnup values on a per compact basis ranged from 11.5 to 19.6 %FIMA, while fast fluence values ranged from 2.21 to 4.39 ?1025 n/m2 (E >0.18 MeV). We’ll say something here about temperatures once thermal recalc is done. Thermocouples performed well, failing at a lower rate than expected. At the end of the irradiation, nine of the originally-planned 19 TCs were considered functional. Fission product release-to-birth (R/B) ratios were quite low. In most capsules, R/B values at the end of the irradiation were at or below 10-7 with only one

  1. AGR 3/4 Irradiation Test Final As Run Report

    Energy Technology Data Exchange (ETDEWEB)

    Collin, Blaise P. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-06-01

    Several fuel and material irradiation experiments have been planned for the Idaho National Laboratory Advanced Reactor Technologies Technology Development Office Advanced Gas Reactor Fuel Development and Qualification Program (referred to as the INL ART TDO/AGR fuel program hereafter), which supports the development and qualification of tristructural-isotropic (TRISO) coated particle fuel for use in HTGRs. The goals of these experiments are to provide irradiation performance data to support fuel process development, qualify fuel for normal operating conditions, support development and validation of fuel performance and fission product transport models and codes, and provide irradiated fuel and materials for post irradiation examination and safety testing (INL 05/2015). AGR-3/4 combined the third and fourth in this series of planned experiments to test TRISO coated low enriched uranium (LEU) oxycarbide fuel. This combined experiment was intended to support the refinement of fission product transport models and to assess the effects of sweep gas impurities on fuel performance and fission product transport by irradiating designed-to-fail fuel particles and by measuring subsequent fission metal transport in fuel-compact matrix material and fuel-element graphite. The AGR 3/4 fuel test was successful in irradiating the fuel compacts to the burnup and fast fluence target ranges, considering the experiment was terminated short of its initial 400 EFPD target (Collin 2015). Out of the 48 AGR-3/4 compacts, 42 achieved the specified burnup of at least 6% fissions per initial heavy-metal atom (FIMA). Three capsules had a maximum fuel compact average burnup < 10% FIMA, one more than originally specified, and the maximum fuel compact average burnup was <19% FIMA for the remaining capsules, as specified. Fast neutron fluence fell in the expected range of 1.0 to 5.5×1025 n/m2 (E >0.18 MeV) for all compacts. In addition, the AGR-3/4 experiment was globally successful in keeping the

  2. For sale: 7 AGR stations and a brand new PWR

    International Nuclear Information System (INIS)

    Britain's seven AGR stations and the Sizewell B PWR will pass to private ownership under the UK government's plan to privatise the two nuclear generators, Nuclear Electric and Scottish Nuclear, sometime next year. Under the new set-up, the two generators will become operating subsidiaries of a holding company which will be headquartered in Scotland. The companies' ageing Magnox gas-cooled reactors will remain in a separate public sector company before being transferred to British Nuclear Fuels (BNFL) at the time of privatisation. (author)

  3. PIE on Safety-Tested AGR-1 Compact 5-1-1

    Energy Technology Data Exchange (ETDEWEB)

    Hunn, John D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Morris, Robert Noel [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Baldwin, Charles A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Montgomery, Fred C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gerczak, Tyler J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-08-01

    Post-irradiation examination (PIE) is being performed in support of tristructural isotropic (TRISO) coated particle fuel development and qualification for High-Temperature Gas-cooled Reactors (HTGRs). AGR-1 was the first in a series of TRISO fuel irradiation experiments initiated in 2006 under the Advanced Gas Reactor (AGR) Fuel Development and Qualification Program; this work continues to be funded by the Department of Energy's Office of Nuclear Energy as part of the Advanced Reactor Technologies (ART) initiative. AGR-1 fuel compacts were fabricated at Oak Ridge National Laboratory (ORNL) in 2006 and irradiated for three years in the Idaho National Laboratory (INL) Advanced Test Reactor (ATR) to demonstrate and evaluate fuel performance under HTGR irradiation conditions. PIE is being performed at INL and ORNL to study how the fuel behaved during irradiation, and to examine fuel performance during exposure to elevated temperatures at or above temperatures that could occur during a depressurized conduction cooldown event. This report summarizes safety testing of irradiated AGR-1 Compact 5-1-1 in the ORNL Core Conduction Cooldown Test Facility (CCCTF) and post-safety testing PIE.

  4. Uncertainty Quantification of Calculated Temperatures for the AGR 3/4 Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Binh Thi-Cam [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    A series of Advanced Gas Reactor (AGR) irradiation experiments are being conducted within the Advanced Reactor Technology (ART) Fuel Development and Qualification Program. The main objectives of the fuel experimental campaign are to provide the necessary data on fuel performance to support fuel process development, qualify a fuel design and fabrication process for normal operation and accident conditions, and support development and validation of fuel performance and fission product transport models and codes (PLN 3636, “Technical Program Plan for INL Advanced Reactor Technologies Technology Development Office/Advanced Gas Reactor Fuel Development and Qualification Program”). The AGR 3/4 test was inserted in the Northeast Flux Trap position in the Advanced Test Reactor (ATR) core at Idaho National Laboratory (INL) in December 2011 and successfully completed irradiation in mid-April 2014, resulting in irradiation of the tristructural isotropic (TRISO) fuel for 369.1 effective full-power days (EFPDs) during approximately 2.4 calendar years. The AGR 3/4 data, including the irradiation data and calculated results, were qualified and stored in the Nuclear Data Management and Analysis System (NDMAS). To support the U.S. TRISO fuel performance assessment and to provide data for validation of fuel performance and fission product transport models and codes, the daily as run thermal analysis has been performed separately on each of twelve AGR 3/4 capsules for the entire irradiation as discussed in ECAR-2807, “AGR 3/4 Daily As Run Thermal Analyses”. The ABAQUS code’s finite element-based thermal model predicts the daily average volume average (VA) fuel temperature (FT), peak FT, and graphite matrix, sleeve, and sink temperature in each capsule. The JMOCUP simulation codes were also created to perform depletion calculations for the AGR 3/4 experiment (ECAR-2753, “JMOCUP As-Run Daily Physics Depletion Calculation for the AGR 3/4 TRISO Particle Experiment in ATR

  5. Uncertainty Quantification of Calculated Temperatures for the AGR 3/4 Experiment

    International Nuclear Information System (INIS)

    A series of Advanced Gas Reactor (AGR) irradiation experiments are being conducted within the Advanced Reactor Technology (ART) Fuel Development and Qualification Program. The main objectives of the fuel experimental campaign are to provide the necessary data on fuel performance to support fuel process development, qualify a fuel design and fabrication process for normal operation and accident conditions, and support development and validation of fuel performance and fission product transport models and codes (PLN 3636, 'Technical Program Plan for INL Advanced Reactor Technologies Technology Development Office/Advanced Gas Reactor Fuel Development and Qualification Program'). The AGR 3/4 test was inserted in the Northeast Flux Trap position in the Advanced Test Reactor (ATR) core at Idaho National Laboratory (INL) in December 2011 and successfully completed irradiation in mid-April 2014, resulting in irradiation of the tristructural isotropic (TRISO) fuel for 369.1 effective full-power days (EFPDs) during approximately 2.4 calendar years. The AGR 3/4 data, including the irradiation data and calculated results, were qualified and stored in the Nuclear Data Management and Analysis System (NDMAS). To support the U.S. TRISO fuel performance assessment and to provide data for validation of fuel performance and fission product transport models and codes, the daily as run thermal analysis has been performed separately on each of twelve AGR 3/4 capsules for the entire irradiation as discussed in ECAR-2807, 'AGR 3/4 Daily As Run Thermal Analyses'. The ABAQUS code's finite element-based thermal model predicts the daily average volume average (VA) fuel temperature (FT), peak FT, and graphite matrix, sleeve, and sink temperature in each capsule. The JMOCUP simulation codes were also created to perform depletion calculations for the AGR 3/4 experiment (ECAR-2753, 'JMOCUP As-Run Daily Physics Depletion Calculation for the AGR 3/4 TRISO Particle

  6. The 1977-1979 geological and hydrogeological investigations at the Windscale Works, Sellafield, Cumbria

    International Nuclear Information System (INIS)

    In late 1976 an investigation was initiated to examine the geological and hydrogeological conditions beneath the Windscale Works, Sellafield, which is owned by British Nuclear Fuels Ltd. Sixty-two boreholes have been drilled, forming a grid of monitoring points. The geological succession comprises predominantly a sequence of gravels, sands, silts and clays which are very variable in thickness and lithology and which are overlain by up to 3m of Made Ground. These unconsolidated deposits of glacial and fluvioglacial origin overlie a fine-grained, well cemented Triassic sandstone, the St Bees Sandstone. The surface of the sandstone incorporates a channel which runs westwards across the site. The unconsolidated glacial deposits contain two types of groundwater bodies. Perched groundwater occurs in several areas but the main occurrence is in the deposits underlying the entire site at depths of between 3 and 15m below ground level. In the central section an extensive silty sand deposit divides the main groundwater body into an upper and lower aquifer. Water levels in the upper aquifer are at greater elevations than those in the lower. The St Bees Sandstone also contains groundwater which appears to be in hydraulic continuity with that in the glacial deposits. Groundwater flow in the main glacial and sandstone aquifers is westwards towards the coast. However the flow directions are complicated by two groundwater recharge mounds, one of natural origin and one which may be of partly artificial origin resulting from the industrialisation of the site. (author)

  7. Reactor accidents in perspective

    International Nuclear Information System (INIS)

    In each of the three major reactor accidents which have led to significant releases to the environment, and discussed in outline in this note, the reactor has been essentially destroyed - certainly Windscale and Chernobyl reactors will never operate and the cleanup operation for Three Mile Island is currently estimated to have cost in excess of US Pound 500 000 000. In each of the accidents there has not been any fatality off site in the short term and any long-term health detriment is unlikely to be seen in comparison with the natural cancer incidence rate. At Chernobyl, early fatalities did occur amongst those concerned with fighting the incident on site and late effects are to be expected. The assumption of a linear non-threshold risk, and hence no level of zero risk is the main problem in communication with the public, and the author calls for simplification of the presentation of the concepts of radiological protection. (U.K.)

  8. An assessment of the primary mechanisms controlling the pre-interlinkage release of stable fission gas using an AGR database

    International Nuclear Information System (INIS)

    Since 1981 measurements have been made at Windscale of the stable fission gas release from Commercial Advanced Gas-Cooled Reactor pins. In all, to date, over 900 measurements have been made on fuel irradiated in the Hunterston B and Hinkley Point B reactors, the vast majority exhibiting only pre-interlinkage release. The pins, which consist of hollow pelleted uranium dioxide fuel clad in stainless steel, have been irradiated with a wide range of cladding temperatures, fuel ratings and burnups and the observed releases are shown to be extremely well correlated with these primary irradiation parameters. The database has therefore proved an almost ideal basis for benchmarking current theories of pre-interlinkage gas release. The primary mechanism of release is shown to be diffusion to free surfaces and analysis allows inferences to be drawn as to the diffusion processes occurring and the dimensions of the free surfaces involved in release. (author)

  9. Quantity of 135I Released from the AGR 1, AGR 2, and AGR 3/4 Experiments and Discovery of 131I at the FPMS Traps during the AGR-3/4 Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Dawn Scates

    2014-09-01

    A series of three Advanced Gas Reactor (AGR) experiments have been conducted in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL). From 2006 through 2014, these experiments supported the development and qualification of the new U.S. tristructural isotropic (TRISO) particle fuel for Very High Temperature Reactors (VHTR). Each AGR experiment consisted of multiple fueled capsules, each plumbed for independent temperature control using a mix of helium and neon gases. The gas leaving a capsule was routed to individual Fission Product Monitor (FPM) detectors. For intact fuel particles, the TRISO particle coatings provide a substantial barrier to fission product release. However, particles with failed coatings, whether because of a minute percentage of initially defective particles, those which fail during irradiation, or those designed to fail (DTF) particles, can release fission products to the flowing gas stream. Because reactive fission product elements like iodine and cesium quickly deposit on cooler capsule components and piping structures as the effluent gas leaves the reactor core, only the noble fission gas isotopes of Kr and Xe tend to reach FPM detectors. The FPM system utilizes High Purity Germanium (HPGe) detectors coupled with a thallium activated sodium iodide NaI(Tl) scintillator. The HPGe detector provides individual isotopic information, while the NaI(Tl) scintillator is used as a gross count rate meter. During irradiation, the 135mXe concentration reaching the FPM detectors is from both direct fission and by decay of the accumulated 135I. About 2.5 hours after irradiation (ten 15.3 minute 135mXe half lives) the directly produced 135mXe has decayed and only the longer lived 135I remains as a source. Decay systematics dictate that 135mXe will be in secular equilibrium with its 135I parent, such that its production rate very nearly equals the decay rate of the parent, and its concentration in the flowing gas stream will appear to decay

  10. The description of Wigner energy and its release from Windscale Pile graphite for application to waste packaging and disposal

    International Nuclear Information System (INIS)

    The graphite core of Windscale Pile 1 is to be dismantled and packaged for interim storage, together with graphite items, such as dowels and boats from both Pile 1 and 2. These retain substantial amounts of Wigner energy and thus to support their packaging, storage and ultimate disposal, it is necessary to understand the release of the Wigner energy in slow, low temperature cycles, driven by the exothermic curing of the grout. The basic theories of the accumulation of Wigner energy and its release are reviewed. These show that the lattice defects introduced by neutron irradiation form a population of sites of different energies which is independent of the graphite type. The release of energy from each type of site can be described by a rate expression which is first order in the stored energy of the site, S, and has an associated activation energy, E, of decay. The overall rate of release, S, is given by a sum over the population of sites and has an effective lower limit determined by irradiation temperatures or post-irradiation conditions. In order to predict the release of Wigner energy activation energy spectra are derived from differential scanning calorimetry of samples of Windscale graphite. It is shown, by numerical solution of the release equation, that the derived spectra predict well both the experimental data and the release of energy from specimens derived from the same sample of Windscale graphite but subjected to different temperature cycles. Simulation of stored energy release in anticipated storage conditions, where the graphite is subjected to a slow temperature cycle driven by the exothermic curing of the grout, shows that only a small portion of the total stored energy is released. The slower the cycle, the greater the proportion of energy release, but the rate of release is slower. (author)

  11. Evidence to the Windscale Inquiry on the safety assessment of nuclear fuel reprocessing storage and ancillary activities

    International Nuclear Information System (INIS)

    The evidence falls under the following headings: proof of evidence - part 1; description of witness; nature of evidence; need for a safety analysis; general form of a safety analysis; THORP safety analysis; safety information provided to the inquiry; why has complete information not been provided (query); who should conduct the safety analysis (query); conclusions; proof of evidence - part 2; nature of this further evidence (details of some accident sequences and their consequences are presented for Windscale); hazard areas considered for accidents; HAW (high-active waste) tank release; SFS (spent fuel storage) pond release; determination of consequences; conclusions. (U.K.)

  12. Corrosion Inhibition Studies in Support of the Long Term Storage of AGR Fuel

    International Nuclear Information System (INIS)

    Thorp receipt and storage (TR&S), Sellafield, UK has been chosen as the optimum facility to be used for the long term, interim wet storage of Advanced Gas Reactor (AGR) fuel. TR&S is currently a demineralised water pond due to a materials compatibility issue. However, a proportion of AGR spent fuel is known to be susceptible to corrosion through inter-granular attack (IGA). To avoid this, the chosen interim storage regime for AGR fuel is sodium hydroxide dosed pond water to pH 11.4. Some fuel has been safely stored in these conditions for 24 years in other Sellafield fuel ponds. For the period until the materials that are incompatible with pH 11.4 have been removed from the pond, a temporary pond water chemistry will be introduced to offer some corrosion protection. Lead container studies have been used to evaluate sodium nitrate (10 ppm) and ‘Low Dose’ sodium hydroxide (pH 9). ‘Low Dose’ conditions have been chosen for implementation. Objectives: • To underpin and implement temporary pond water chemistry for AGR storage; • To develop and deliver a programme of work to support the transition and safety case delivery for interim storage of AGR fuel

  13. Application of materials and fabrication with respect to current and next generation AGR steam generators (based on Hinkley B and Hunterston B AGRs)

    International Nuclear Information System (INIS)

    The Magnox Reactor experience is briefly reviewed showing the progressive development through Oldbury to the current A.G.R. The increasing power density has given rise to more restrictions in the fabrication of the steam generator. This has resulted in a steadily increasing demand for mechanised fabrication techniques to ensure adequate precision during manufacture. The Hinkley Hunterston A.G.R. reflects this in the development and utilisation of orbital welding, 1 D bends and remote repair devices together with controlled atmosphere heat treatment. Identification of fretting phenomena associated with the original design of Hinkley B steam generator supports resulted in a welded support design and an extensive substantiation programme. The theme of continuity of experience is maintained in the programme of work now in hand for the second generation A.G.R.'s (Heysham II and Torness). Material specifications have been strongly influenced by the current A.G.R programme and fabrication experience. Special attention is being given to improved fabrication techniques, typically improved orbital welding equipment will be implemented progressively in accordance with production acceptance trials. (author)

  14. Seminar on Comparative assessment of the environmental impact of radionuclides released during three major nuclear accidents: Kyshtym, Windscale, Chernobyl. Vol. 1

    International Nuclear Information System (INIS)

    These proceedings of seminar on comparative assessment of the environmental impact of radionuclides released during three major nuclear accidents (Kyshtym, Windscale, Chernobyl) are divided into 5 parts bearing on: part 1: accident source terms; part 2: atmospheric dispersion, resuspension, chemical and physical forms of contamination; part 3: environmental contamination and transfer; part 4: radiological implications for man and his environment; part 5: countermeasures

  15. Evaluation of graphite safety issues for the British production piles at Windscale: Graphite sampling in preparation for the dismantling of Pile 1 and the further safe storage of Pile 2

    International Nuclear Information System (INIS)

    The two air-cooled graphite-moderated production piles at the UK Sellafield site (formerly Windscale) have not operated since the late 1950s following the fire in Pile no. 1 in 1957. Although limited graphite trepanning took place immediately following the fire (mainly in the undamaged reactor, Pile no. 2), it has been deemed necessary to obtain new samples and extensive data to support the intended programme, which is for further 'Safe Storage' of Pile 2 and for the dismantling of Pile no. 1. The reactors (especially Pile no.2) contain significant Wigner energy, and elaborate precautions have been applied to ensure that intrusive operations cannot lead to energy releases. The paper discusses the visual surveys, trepanning procedure and the analytical data which have been obtained from the samples. There appear to be no obstacles to the continued storage of Pile no.2. For Pile no.1, the data will be used to support the safety case now being developed for dismantling and will define acceptable handling, storage and disposal procedures for the graphite blocks. (author)

  16. Plant Measurement, Sampling and Analysis for Accountancy Purposes with Particular Reference to Separation Plants at Windscale

    International Nuclear Information System (INIS)

    All figures for special materials accountancy purposes contain one or more of three parameters, namely plant measurement, sampling and analysis. For plant measurements it is best to use weighings wherever possible, e.g. the plutonium in the feed to the New Separation Plant is based on the weight of uranium rods fed. Methods used for measuring volumes are discussed, e.g. (a) pneumercator, and (b) tracer method using radioactive caesium. Judged accuracies and precisions of each method are given. The sampling of solutions in a batch process is done by using evacuated tubes after thorough homogenization of the solution. For ''flowing'' streams, where high accuracy is required, a continuous sampler has been devised and is used on the feed to the New Separation Plant. Drilling of metal ingots is the normal sampling method at Windscale, whereas for other solids the method is to homogenize as far as possible (e.g. a Y cone blender is used for plutonium oxide) and then sample. For the chemical analysis, the precision required of the method depends on the number of determinations in each accounting period. Thus a large number of analyses are required for an accurate but imprecise method. It may be more economical to use fewer determinations with a more precise method. Methods for determining plutonium are discussed in detail, e.g. (a) radiochemistry, (b) colorimetrically using thoronol, (c) plutonium separation, complexing with EDTA and back titration of the excess EDTA, (d) titrimetry (e) isotope dilution followed by mass spectrometry and (f) differential spectrometry. Methods for determining uranium are outlined, e.g. (a) gravimetry as U3O8, (b) ether extraction followed by gravimetry or colorimetry, (c) titrimetry, (d) isotope dilution followed by mass spectrometry and (e) enrichment determination by mass spectrometry or line shift emission spectrography. With all accounting methods standards are used to give quality control and to show any inaccuracy which requires to be

  17. AGR-5/6/7 LEUCO Kernel Fabrication Readiness Review

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, Douglas W. [Idaho National Lab. (INL), Idaho Falls, ID (United States). Fuel Design and Development; Bailey, Kirk W. [Idaho National Lab. (INL), Idaho Falls, ID (United States). ART Quality Assurance Engineer

    2015-02-01

    In preparation for forming low-enriched uranium carbide/oxide (LEUCO) fuel kernels for the Advanced Gas Reactor (AGR) fuel development and qualification program, Idaho National Laboratory conducted an operational readiness review of the Babcock & Wilcox Nuclear Operations Group – Lynchburg (B&W NOG-L) procedures, processes, and equipment from January 14 – January 16, 2015. The readiness review focused on requirements taken from the American Society Mechanical Engineers (ASME) Nuclear Quality Assurance Standard (NQA-1-2008, 1a-2009), a recent occurrence at the B&W NOG-L facility related to preparation of acid-deficient uranyl nitrate solution (ADUN), and a relook at concerns noted in a previous review. Topic areas open for the review were communicated to B&W NOG-L in advance of the on-site visit to facilitate the collection of objective evidences attesting to the state of readiness.

  18. DETERMINATION OF THE QUANTITY OF I-135 RELEASED FROM THE AGR-1 TEST FUELS AT THE END OF ATR OPERATING CYCLE 138B

    Energy Technology Data Exchange (ETDEWEB)

    J. K. Hartwell; D. M. Scates; J. B. Walter; M. W. Drigert

    2007-05-01

    The AGR-1 experiment is a multiple fueled-capsule irradiation experiment being conducted in the Advanced Test Reactor (ATR) in support of the Advanced Gas Reactor (AGR) Fuel Development and Qualification Program. The experiment began irradiation in the ATR with a cycle that reached full power on December 26, 2006 and ended with shutdown of the reactor for a brief outage on February 10, 2007 at 0900. The AGR-1 experiment will continue cyclical irradiation for about 2.5 years. In order to allow estimation of the amount of radioiodine released during the first cycle, purge gas flow to all capsules continued for about 4 days after reactor shutdown. The FPMS data acquired during part of that shutdown flow period has been analyzed to elucidate the level of 135I released during the operating cycle.

  19. 15 CFR 740.18 - Agricultural commodities (AGR).

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Agricultural commodities (AGR). 740.18... EXCEPTIONS § 740.18 Agricultural commodities (AGR). (a) Eligibility requirements. License Exception AGR permits the export of agricultural commodities to Cuba, as well as the reexport of U.S....

  20. Estudio de Salud Agrícola

    Science.gov (United States)

    En 1993, científicos del Instituto Nacional del Cáncer, Instituto Nacional de Ciencias Ambientales y la Agencia de Protección Ambiental de Estados Unidos iniciaron un estudio conocido como Estudio de Salud Agrícola (AHS).

  1. Data Compilation for AGR-1 Variant 3 Coated Particle Composite LEU01-49T

    Energy Technology Data Exchange (ETDEWEB)

    Hunn, John D [ORNL; Lowden, Richard Andrew [ORNL

    2006-07-01

    This document is a compilation of characterization data for the AGR-1 variant 3 coated particle composite LEU01-49T, a composite of three batches of TRISO-coated 350 {micro}m diameter 19.7% low enrichment uranium oxide/uranium carbide kernels (LEUCO). The AGR-1 TRISO-coated particles consist of a spherical kernel coated with a {approx} 50% dense carbon buffer layer (100 {micro}m nominal thickness) followed by a dense inner pyrocarbon layer (40 {micro}m nominal thickness) followed by a SiC layer (35 {micro}m nominal thickness) followed by another dense outer pyrcoarbon layer (40 {micro}m nominal thickness). The coated particles were produced by ORNL for the Advanced Gas Reactor Fuel Development and Qualification (AGR) program to be put into compacts for the fuel shakedown irradiation (AGR-1) experiment. The kernels were obtained from BWXT and identified as composite G73D-20-6302. The BWXT kernel lot G73D-20-69302 was riffled into sublots for characterization and coating by ORNL and identified as LEUO01-?? (where ?? is a series of integers beginning with 01).

  2. AGR-3/4 Final Data Qualification Report for ATR Cycles 151A through 155B-1

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Binh T. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-01

    This report provides the qualification status of experimental data for the entire Advanced Gas Reactor 3/4 (AGR 3/4) fuel irradiation. AGR-3/4 is the third in a series of planned irradiation experiments conducted in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) for the AGR Fuel Development and Qualification Program, which supports development of the advanced reactor technology under the INL ART Technology Development Office (TDO). The main objective of AGR-3/4 irradiation is to provide a known source of fission products for subsequent transport through compact matrix and structural graphite materials due to the presence of designed-to-fail fuel particles. Full power irradiation of the AGR 3/4 test began on December 14, 2011 (ATR Cycle 151A), and was completed on April 12, 2014 (end of ATR Cycle 155B) after 369.1 effective full power days of irradiation. The AGR-3/4 test was in the reactor core for eight of the ten ATR cycles between 151A and 155B. During the unplanned outage cycle, 153A, the experiment was removed from the ATR northeast flux trap (NEFT) location and stored in the ATR canal. This was to prevent overheating of fuel compacts due to higher than normal ATR power during the subsequent Powered Axial Locator Mechanism cycle, 153B. The AGR 3/4 test was inserted back into the ATR NEFT location during the outage of ATR Cycle 154A on April 26, 2013. Therefore, the AGR-3/4 irradiation data received during these 2 cycles (153A and 153B) are irrelevant and their qualification status isnot included in this report. Additionally, during ATR Cycle 152A the ATR core ran at low power for a short enough duration that the irradiation data are not used for physics and thermal calculations. However, the qualification status of irradiation data for this cycle is still covered in this report. As a result, this report includes data from 8 ATR Cycles: 151A, 151B, 152A, 152B, 154A, 154B, 155A, and 155B, as recorded in the Nuclear Data Management and

  3. Manufacture of steam generator units and components for the AGR power stations at Heysham II and Torness

    International Nuclear Information System (INIS)

    The current AGR Steam Generator is a development of the successful once-through units supplied for the Oldbury Magnox and Hinkley B/Hunterston B AGR power stations. In this paper a brief outline of the evolution of the steam generator design from the earlier gas cooled reactor stations is presented. A description of the main items of fabrication development is given. The production facilities for the manufacture of the units are described. Reference is also made to some of the work on associated components. The early experience on the construction site of installation of the steam generators is briefly outlined. (author)

  4. Data Compilation for AGR-1 Baseline Coated Particle Composite LEU01-46T

    Energy Technology Data Exchange (ETDEWEB)

    Hunn, John D [ORNL; Lowden, Richard Andrew [ORNL

    2006-04-01

    This document is a compilation of characterization data for the AGR-1 baseline coated particle composite LEU01-46T, a composite of four batches of TRISO-coated 350 {micro}m 19.7% low enrichment uranium oxide/uranium carbide kernels (LEUCO). The AGR-1 TRISO-coated particles consist of a spherical kernel coated with a {approx} 50% dense carbon buffer layer (100 {micro}m nominal thickness) followed by a dense inner pyrocarbonlayer (40 {micro}m nominal thickness) followed by a SiC layer (35 {micro}m nominal thickness) followed by another dense outer pyrocarbon layer (40 {micro}m nominal thickness). The coated particles, were produced by ORNL for the Advanced Gas Reactor Fuel Development and Qualification (AGR) program to be put into compacts for insertion in the first irradiation test capsule, AGR-1. The kernels were obtained from BWXT and identified as composite (G73D-20-69302). The BWXT kernel lot G73D-20-69302 was riffled into sublots for characterization and coating by ORNL and identified as LEU01-?? (where ?? is a series of integers beginning with 01). Additional particle batches were coated with only buffer or buffer plus inner pyrocarbon (IPyC) layers using similar process conditions as used for the full TRISO batches comprising the LEU01-46T composite. These batches were fabricated in order to qualify that the process conditions used for buffer and IPyC would produce acceptable densities, as described in sections 8 and 9. These qualifying batches used 350 {micro}m natural uranium oxide/uranium carbide kernels (NUCO). The kernels were obtained from BWXT and identified as composite G73B-NU-69300. The use of NUCO surrogate kernels is not expected to significantly effect the densities of the buffer and IPyC coatings. Confirmatory batches using LEUCO kernels from G73D-20-69302 were coated and characterized to verify this assumption. The AGR-1 Fuel Product Specification and Characterization Guidance (INL EDF-4380, Rev. 6) provides the requirements necessary for

  5. AGR-2 irradiation test final as-run report, Rev. 1

    Energy Technology Data Exchange (ETDEWEB)

    Collin, Blaise

    2014-08-01

    This document presents the as-run analysis of the AGR-2 irradiation experiment. AGR-2 is the second of the planned irradiations for the Advanced Gas Reactor (AGR) Fuel Development and Qualification Program. Funding for this program is provided by the U.S. Department of Energy as part of the Very High Temperature Reactor (VHTR) Technical Development Office (TDO) program. The objectives of the AGR-2 experiment are to: (a) Irradiate UCO (uranium oxycarbide) and UO2 (uranium dioxide) fuel produced in a large coater. Fuel attributes are based on results obtained from the AGR-1 test and other project activities; (b) Provide irradiated fuel samples for post-irradiation experiment (PIE) and safety testing; and, (c) Support the development of an understanding of the relationship between fuel fabrication processes, fuel product properties, and irradiation performance. The primary objective of the test was to irradiate both UCO and UO2 TRISO (tri-structural isotropic) fuel produced from prototypic scale equipment to obtain normal operation and accident condition fuel performance data. The UCO compacts were subjected to a range of burnups and temperatures typical of anticipated prismatic reactor service conditions in three capsules. The test train also includes compacts containing UO2 particles produced independently by the United States, South Africa, and France in three separate capsules. The range of burnups and temperatures in these capsules were typical of anticipated pebble bed reactor service conditions. The results discussed in this report pertain only to U.S. produced fuel. In order to achieve the test objectives, the AGR-2 experiment was irradiated in the B-12 position of the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) for a total irradiation duration of 559.2 effective full power days (EFPD). Irradiation began on June 22, 2010, and ended on October 16, 2013, spanning 12 ATR power cycles and approximately three and a half calendar years. The test

  6. AGR-2 Irradiation Test Final As-Run Report, Rev 2

    Energy Technology Data Exchange (ETDEWEB)

    Blaise Collin

    2014-08-01

    This document presents the as-run analysis of the AGR-2 irradiation experiment. AGR-2 is the second of the planned irradiations for the Advanced Gas Reactor (AGR) Fuel Development and Qualification Program. Funding for this program is provided by the U.S. Department of Energy as part of the Very High Temperature Reactor (VHTR) Technical Development Office (TDO) program. The objectives of the AGR-2 experiment are to: (a) Irradiate UCO (uranium oxycarbide) and UO2 (uranium dioxide) fuel produced in a large coater. Fuel attributes are based on results obtained from the AGR-1 test and other project activities. (b) Provide irradiated fuel samples for post-irradiation experiment (PIE) and safety testing. (c) Support the development of an understanding of the relationship between fuel fabrication processes, fuel product properties, and irradiation performance. The primary objective of the test was to irradiate both UCO and UO2 TRISO (tri-structural isotropic) fuel produced from prototypic scale equipment to obtain normal operation and accident condition fuel performance data. The UCO compacts were subjected to a range of burnups and temperatures typical of anticipated prismatic reactor service conditions in three capsules. The test train also includes compacts containing UO2 particles produced independently by the United States, South Africa, and France in three separate capsules. The range of burnups and temperatures in these capsules were typical of anticipated pebble bed reactor service conditions. The results discussed in this report pertain only to U.S. produced fuel. In order to achieve the test objectives, the AGR-2 experiment was irradiated in the B-12 position of the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) for a total irradiation duration of 559.2 effective full power days (EFPD). Irradiation began on June 22, 2010, and ended on October 16, 2013, spanning 12 ATR power cycles and approximately three and a half calendar years. The test

  7. Cost effective use of software in AGR safety applications

    International Nuclear Information System (INIS)

    Economic pressures on Scottish Nuclear have been significant since its retention in state ownership following the UK's Electrical Supply Industry (ESI) privatisation two years ago, and will continue to increase as other utilities' generation costs become more competitive. Software systems play a significant role in both the maintenance of safety claims and in the output of Scottish Nuclear's Advanced Gas-cooled Reactor (AGR) generating plant. This paper takes as its theme Scottish Nuclear's positive and negative experiences with high reliability software. A cost effective software life cycle for the maintenance of safety related software with unreliability demands in the range 1.0E-1 to 1.0E-2 pfd for reactor control and fuel handling applications based on a customer-software integrator-software supplier model is described. Experience from the evolution of this life cycle has led to the concept of an integrated software maintenance environment. The problems leading to Scottish Nuclear's move away from the use of software for safety critical (1.0E-4 pfd) applications and its substitution by non-processor technology on the fuel route are outlined. Finally the paper describes Scottish Nuclear's medium term policy for the engineering of safety critical applications. (Author) 2 refs., 3 figs

  8. Uncertainty Quantification of Calculated Temperatures for the U.S. Capsules in the AGR-2 Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Lybeck, Nancy [Idaho National Lab. (INL), Idaho Falls, ID (United States); Einerson, Jeffrey J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Pham, Binh T. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hawkes, Grant L. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-01

    A series of Advanced Gas Reactor (AGR) irradiation experiments are being conducted within the Advanced Reactor Technology (ART) Fuel Development and Qualification Program. The main objectives of the fuel experimental campaign are to provide the necessary data on fuel performance to support fuel process development, qualify a fuel design and fabrication process for normal operation and accident conditions, and support development and validation of fuel performance and fission product transport models and codes (PLN-3636). The AGR-2 test was inserted in the B-12 position in the Advanced Test Reactor (ATR) core at Idaho National Laboratory (INL) in June 2010 and successfully completed irradiation in October 2013, resulting in irradiation of the TRISO fuel for 559.2 effective full power days (EFPDs) during approximately 3.3 calendar years. The AGR-2 data, including the irradiation data and calculated results, were qualified and stored in the Nuclear Data Management and Analysis System (NDMAS) (Pham and Einerson 2014). To support the U.S. TRISO fuel performance assessment and to provide data for validation of fuel performance and fission product transport models and codes, the daily as-run thermal analysis has been performed separately on each of four AGR-2 U.S. capsules for the entire irradiation as discussed in (Hawkes 2014). The ABAQUS code’s finite element-based thermal model predicts the daily average volume-average fuel temperature and peak fuel temperature in each capsule. This thermal model involves complex physical mechanisms (e.g., graphite holder and fuel compact shrinkage) and properties (e.g., conductivity and density). Therefore, the thermal model predictions are affected by uncertainty in input parameters and by incomplete knowledge of the underlying physics leading to modeling assumptions. Therefore, alongside with the deterministic predictions from a set of input thermal conditions, information about prediction uncertainty is instrumental for the ART

  9. AGR-1 Irradiation Test Final As-Run Report, Rev. 3

    International Nuclear Information System (INIS)

    This document presents the as-run analysis of the AGR-1 irradiation experiment. AGR-1 is the first of eight planned irradiations for the Advanced Gas Reactor (AGR) Fuel Development and Qualification Program. Funding for this program is provided by the US Department of Energy (DOE) as part of the Next-Generation Nuclear Plant (NGNP) project. The objectives of the AGR-1 experiment are: 1. To gain experience with multi-capsule test train design, fabrication, and operation with the intent to reduce the probability of capsule or test train failure in subsequent irradiation tests. 2. To irradiate fuel produced in conjunction with the AGR fuel process development effort. 3. To provide data that will support the development of an understanding of the relationship between fuel fabrication processes, fuel product properties, and irradiation performance. In order to achieve the test objectives, the AGR-1 experiment was irradiated in the B-10 position of the Advanced Test Reactor (ATR) at the Idaho National Laboratory (INL) for a total duration of 620 effective full power days of irradiation. Irradiation began on December 24, 2006 and ended on November 6, 2009 spanning 13 ATR cycles and approximately three calendar years. The test contained six independently controlled and monitored capsules. Each capsule contained 12 compacts of a single type, or variant, of the AGR coated fuel. No fuel particles failed during the AGR-1 irradiation. Final burnup values on a per compact basis ranged from 11.5 to 19.6 %FIMA, while fast fluence values ranged from 2.21 to 4.39 x 1025 n/m2 (E >0.18 MeV). We'll say something here about temperatures once thermal recalc is done. Thermocouples performed well, failing at a lower rate than expected. At the end of the irradiation, nine of the originally-planned 19 TCs were considered functional. Fission product release-to-birth (R/B) ratios were quite low. In most capsules, R/B values at the end of the irradiation were at or below 10-7 with only one

  10. AGR-1 Irradiation Test Final As-Run Report, Rev. 3

    Energy Technology Data Exchange (ETDEWEB)

    Collin, Blaise P.

    2015-01-01

    This document presents the as-run analysis of the AGR-1 irradiation experiment. AGR-1 is the first of eight planned irradiations for the Advanced Gas Reactor (AGR) Fuel Development and Qualification Program. Funding for this program is provided by the US Department of Energy (DOE) as part of the Next-Generation Nuclear Plant (NGNP) project. The objectives of the AGR-1 experiment are: 1. To gain experience with multi-capsule test train design, fabrication, and operation with the intent to reduce the probability of capsule or test train failure in subsequent irradiation tests. 2. To irradiate fuel produced in conjunction with the AGR fuel process development effort. 3. To provide data that will support the development of an understanding of the relationship between fuel fabrication processes, fuel product properties, and irradiation performance. In order to achieve the test objectives, the AGR-1 experiment was irradiated in the B-10 position of the Advanced Test Reactor (ATR) at the Idaho National Laboratory (INL) for a total duration of 620 effective full power days of irradiation. Irradiation began on December 24, 2006 and ended on November 6, 2009 spanning 13 ATR cycles and approximately three calendar years. The test contained six independently controlled and monitored capsules. Each capsule contained 12 compacts of a single type, or variant, of the AGR coated fuel. No fuel particles failed during the AGR-1 irradiation. Final burnup values on a per compact basis ranged from 11.5 to 19.6 %FIMA, while fast fluence values ranged from 2.21 to 4.39 x 1025 n/m2 (E >0.18 MeV). We’ll say something here about temperatures once thermal recalc is done. Thermocouples performed well, failing at a lower rate than expected. At the end of the irradiation, nine of the originally-planned 19 TCs were considered functional. Fission product release-to-birth (R/B) ratios were quite low. In most capsules, R/B values at the end of the irradiation were at or below

  11. Identification of the agr Peptide of Listeria monocytogenes

    Science.gov (United States)

    Zetzmann, Marion; Sánchez-Kopper, Andrés; Waidmann, Mark S.; Blombach, Bastian; Riedel, Christian U.

    2016-01-01

    Listeria monocytogenes (Lm) is an important food-borne human pathogen that is able to strive under a wide range of environmental conditions. Its accessory gene regulator (agr) system was shown to impact on biofilm formation and virulence and has been proposed as one of the regulatory mechanisms involved in adaptation to these changing environments. The Lm agr operon is homologous to the Staphylococcus aureus system, which includes an agrD-encoded autoinducing peptide that stimulates expression of the agr genes via the AgrCA two-component system and is required for regulation of target genes. The aim of the present study was to identify the native autoinducing peptide (AIP) of Lm using a luciferase reporter system in wildtype and agrD deficient strains, rational design of synthetic peptides and mass spectrometry. Upon deletion of agrD, luciferase reporter activity driven by the PII promoter of the agr operon was completely abolished and this defect was restored by co-cultivation of the agrD-negative reporter strain with a producer strain. Based on the sequence and structures of known AIPs of other organisms, a set of potential Lm AIPs was designed and tested for PII-activation. This led to the identification of a cyclic pentapeptide that was able to induce PII-driven luciferase reporter activity and restore defective invasion of the agrD deletion mutant into Caco-2 cells. Analysis of supernatants of a recombinant Escherichia coli strain expressing AgrBD identified a peptide identical in mass and charge to the cyclic pentapeptide. The Lm agr system is specific for this pentapeptide since the AIP of Lactobacillus plantarum, which also is a pentapeptide yet with different amino acid sequence, did not induce PII activity. In summary, the presented results provide further evidence for the hypothesis that the agrD gene of Lm encodes a secreted AIP responsible for autoregulation of the agr system of Lm. Additionally, the structure of the native Lm AIP was identified.

  12. Reactors

    International Nuclear Information System (INIS)

    Purpose: To provide a spray cooling structure wherein the steam phase in a bwr reactor vessel can sufficiently be cooled and the upper cap and flanges in the vessel can be cooled rapidly which kept from direct contaction with cold water. Constitution: An apertured shielding is provided in parallel spaced apart from the inner wall surface at the upper portion of a reactor vessel equipped with a spray nozzle, and the lower end of the shielding and the inner wall of the vessel are closed to each other so as to store the cooling water. Upon spray cooling, cooling water jetting out from the nozzle cools the vapor phase in the vessel and then hits against the shielding. Then the cooling water mostly falls as it is, while partially enters through the apertures to the back of the shielding plate, abuts against stoppers and falls down. The stoppers are formed in an inverted L shape so that the spray water may not in direct contaction with the inner wall of the vessel. (Horiuchi, T.)

  13. Improving thermal model prediction through statistical analysis of irradiation and post-irradiation data from AGR experiments

    International Nuclear Information System (INIS)

    As part of the High Temperature Reactors (HTR) R and D program, a series of irradiation tests, designated as Advanced Gas-cooled Reactor (AGR), have been defined to support development and qualification of fuel design, fabrication process, and fuel performance under normal operation and accident conditions. The AGR tests employ fuel compacts placed in a graphite cylinder shrouded by a steel capsule and instrumented with thermocouples (TC) embedded in graphite blocks enabling temperature control. While not possible to obtain by direct measurements in the tests, crucial fuel conditions (e.g., temperature, neutron fast fluence, and burnup) are calculated using core physics and thermal modeling codes. This paper is focused on AGR test fuel temperature predicted by the ABAQUS code's finite element-based thermal models. The work follows up on a previous study, in which several statistical analysis methods were adapted, implemented in the NGNP Data Management and Analysis System (NDMAS), and applied for qualification of AGR-1 thermocouple data. Abnormal trends in measured data revealed by the statistical analysis are traced to either measuring instrument deterioration or physical mechanisms in capsules that may have shifted the system thermal response. The main thrust of this work is to exploit the variety of data obtained in irradiation and post-irradiation examination (PIE) for assessment of modeling assumptions. As an example, the uneven reduction of the control gas gap in Capsule 5 found in the capsule metrology measurements in PIE helps identify mechanisms other than TC drift causing the decrease in TC readings. This suggests a more physics-based modification of the thermal model that leads to a better fit with experimental data, thus reducing model uncertainty and increasing confidence in the calculated fuel temperatures of the AGR-1 test

  14. The Windscale inquiry. Report by the Hon. Mr. Justice Parker, presented to the Secretary of State for the Environment on 26 January 1978

    International Nuclear Information System (INIS)

    This Volume 2 contains Annex 1 - list of appearances, and Annex 2 - list of documents, to the official Report by the Inspector appointed to conduct a local inquiry for the purpose of hearing objections and representations relating to an application by British Nuclear Fuels Limited for planning permission for a plant for reprocessing irradiated oxide nuclear fuels and support services at the Windscale and Calder Works. The volume also contains an alphabetical index to the list of documents. (Volume 1 contains the report of the Inspector and three other of the five Annexes to the report, and Volume 3 contains the Index to the Report). (U.K.)

  15. Mortality and cancer registration experience of the Sellafield employees known to have been involved in the 1957 Windscale accident

    International Nuclear Information System (INIS)

    The mortality and cancer morbidity experience of the 470 male Sellafield employees known to be involved in the 1957 Windscale accident is reported. All these employees are known to have been involved in dealing with the fire itself, or in the clean-up operation afterwards. The size of the study population is small, leading to predicted low power to reveal any effects, but the cohort is of interest because of the involvement of the workers in the accident. For 1957-97, using rates for England and Wales to calculate the expected numbers, the all causes standardised mortality ratio (SMR) is 100 (observed=258, expected=258.80), and the all malignant neoplasms SMR is 79 (observed=58, expected=73.12) which is not significantly different from 100. For 1971-91, the all malignant neoplasms standardised registration ratio (SRR) of 85 (observed=59, expected=69.23) is not significantly different from 100. Significant excesses of deaths from diseases of the circulatory system (SMR=121) and from ischaemic heart disease (SMR=128), and a significant deficit of deaths from cancer of the genito-urinary organs (SMR=31), were found. There were no significant differences in mortality rates between workers who had received high recorded external doses during the fire and those who had received low doses, though the power of this comparison was low. Comparison of the mortality rates of workers directly involved in the accident with workers in post, but not so involved, showed no significant differences. This study has been unable to detect any effect of the 1957 fire upon the mortality and cancer morbidity experience of those workers involved in it. (author)

  16. Gas Reactor International Cooperative Program. Interim report. Construction and operating experience of selected European Gas-Cooled Reactors

    Energy Technology Data Exchange (ETDEWEB)

    1978-09-01

    The construction and operating experience of selected European Gas-Cooled Reactors is summarized along with technical descriptions of the plants. Included in the report are the AVR Experimental Pebble Bed Reactor, the Dragon Reactor, AGR Reactors, and the Thorium High Temperature Reactor (THTR). The study demonstrates that the European experience has been favorable and forms a good foundation for the development of Advanced High Temperature Reactors.

  17. Gas Reactor International Cooperative Program. Interim report. Construction and operating experience of selected European Gas-Cooled Reactors

    International Nuclear Information System (INIS)

    The construction and operating experience of selected European Gas-Cooled Reactors is summarized along with technical descriptions of the plants. Included in the report are the AVR Experimental Pebble Bed Reactor, the Dragon Reactor, AGR Reactors, and the Thorium High Temperature Reactor (THTR). The study demonstrates that the European experience has been favorable and forms a good foundation for the development of Advanced High Temperature Reactors

  18. Windscale nuclear power development laboratories power ramp experience in the Winfrith SGHWR (UK)

    International Nuclear Information System (INIS)

    SGHWR fuel has sufficient power ramping capability to permit considerable latitude in fuel management schemes. However, beyond some limiting ramping conditions, there is risk of fuel defecting. Controlled ramp experiments were therefore carried out in the reactor in order to determine the defect mechanism and define the fuel operating limitations. Cladding cracks produced during these power ramps are considered to have been a consequence of fission product stress-corrosion attack. A critical stress level for cracking, based on laboratory stress corrosion tests, have been used successfully in conjunction with computer codes to calculate cladding stresses and strains in fuel rods. Initial analysis of the conditions under which a fuel element defected at 11.6 MWd/kgU suggests that the threshold stress for failure may be decreased compared with elements at lower burn-up (5-6 MWd/kgU)

  19. El microbioma de un suelo agrícola supresivo

    OpenAIRE

    Vida, Carmen; de Vicente, Antonio; Cazorla, Francisco M.

    2015-01-01

    La aplicación de enmiendas orgánicas es una estrategia agrícola que puede provocar la mejora del estado fitosanitario de los suelos agrícolas. Esta medida se incluye en el control integrado de la podredumbre blanca radicular del aguacate, causada por el hongo fitopatógeno Rosellinia necatrix en la zona Mediterránea. En este trabajo se evalúa la capacidad supresiva de suelos agrícolas del cultivo de aguacate, enmendados con cáscara de almendra compostada. Además se caracteriza la microbiota qu...

  20. Large packages for reactor decommissioning waste

    International Nuclear Information System (INIS)

    This study was carried out jointly by the Atomic Energy Establishment at Winfrith (now called the Winfrith Technology Centre), Windscale Laboratory and Ove Arup and Partners. The work involved the investigation of the design of large transport containers for intermediate level reactor decommissioning waste, ie waste which requires shielding, and is aimed at European requirements (ie for both LWR and gas cooled reactors). It proposes a design methodology for such containers covering the whole lifetime of a waste disposal package. The design methodology presented takes account of various relevant constraints. Both large self shielded and returnable shielded concepts were developed. The work was generic, rather than specific; the results obtained, and the lessons learned, remain to be applied in practice

  1. Validation of the Physics Analysis used to Characterize the AGR-1 TRISO Fuel Irradiation Test

    Energy Technology Data Exchange (ETDEWEB)

    Sterbentz, James W.; Harp, Jason M.; Demkowicz, Paul A.; Hawkes, Grant L.; Chang, Gray S.

    2015-05-01

    The results of a detailed physics depletion calculation used to characterize the AGR-1 TRISO-coated particle fuel test irradiated in the Advanced Test Reactor (ATR) at the Idaho National Laboratory are compared to measured data for the purpose of validation. The particle fuel was irradiated for 13 ATR power cycles over three calendar years. The physics analysis predicts compact burnups ranging from 11.30-19.56% FIMA and cumulative neutron fast fluence from 2.21?4.39E+25 n/m2 under simulated high-temperature gas-cooled reactor conditions in the ATR. The physics depletion calculation can provide a full characterization of all 72 irradiated TRISO-coated particle compacts during and post-irradiation, so validation of this physics calculation was a top priority. The validation of the physics analysis was done through comparisons with available measured experimental data which included: 1) high-resolution gamma scans for compact activity and burnup, 2) mass spectrometry for compact burnup, 3) flux wires for cumulative fast fluence, and 4) mass spectrometry for individual actinide and fission product concentrations. The measured data are generally in very good agreement with the calculated results, and therefore provide an adequate validation of the physics analysis and the results used to characterize the irradiated AGR-1 TRISO fuel.

  2. Nasal Carriage as a Source of agr-Defective Staphylococcus aureus Bacteremia

    OpenAIRE

    Smyth, Davida S.; Kafer, Jared M.; Wasserman, Gregory A.; Velickovic, Lili; Mathema, Barun; Robert S Holzman; Knipe, Tiffany A.; Becker, Karsten; von Eiff, Christof; Peters, Georg; Chen, Liang; Kreiswirth, Barry N.; Novick, Richard P.; Shopsin, Bo

    2012-01-01

    Inactivating mutations in the Staphylococcus aureus virulence regulator agr are associated with worse outcomes in bacteremic patients. However, whether agr dysfunction is primarily a cause or a consequence of early bacteremia is unknown. Analysis of 158 paired S. aureus clones from blood and nasal carriage sites in individual patients revealed that recovery of an agr-defective mutant from blood was usually predicted by the agr functionality of carriage isolates. Many agr-positive blood isolat...

  3. Determination of the Quantity of I-135 Released from the AGR Experiment Series

    Energy Technology Data Exchange (ETDEWEB)

    Scates, Dawn Marie [Idaho National Laboratory; Walter, John Bradley [Idaho National Laboratory; Reber, Edward Lawrence [Idaho National Laboratory; Sterbentz, James William [Idaho National Laboratory; Petti, David Andrew [Idaho National Laboratory

    2014-10-01

    A series of three Advanced Gas Reactor (AGR) experiments have been conducted in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL). From 2006 through 2014, these experiments supported the development and qualification of the new U.S. tri structural isotropic (TRISO) particle fuel for Very High Temperature Reactors (VHTR). Each AGR experiment consisted of multiple fueled capsules, each plumbed for independent temperature control using a mix of helium and neon gases. The gas leaving a capsule was routed to individual Fission Product Monitor (FPM) detectors. For intact fuel particles, the TRISO particle coatings provide a substantial barrier to fission product release. However, particles with failed coatings, whether because of a minute percentage of initially defective particles, those which fail during irradiation, or those designed to fail (DTF) particles, can release fission products to the flowing gas stream. Because reactive fission product elements like iodine and cesium quickly deposit on cooler capsule components and piping structures as the effluent gas leaves the reactor core, only the noble fission gas isotopes of Kr and Xe tend to reach FPM detectors. The FPM system utilizes High Purity Germanium (HPGe) detectors coupled with a thallium activated sodium iodide NaI(Tl) scintillator. The germanium detector provides individual isotopic information, while the NaI(Tl) scintillator is used as a gross count rate meter. During irradiation, the 135mXe concentration reaching the FPM detectors is from both direct fission and by decay of the accumulated 135I. About ~2.5 hours after irradiation (ten 15.3 minute 135mXe half lives) the directly produced 135mXe has decayed and only the longer lived 135I remains as a source. Decay systematics dictate that 135mXe will be in secular equilibrium with its 135I parent, such that it’s production rate very nearly equals the decay rate of the parent, and its concentration in the flowing gas stream will appear to

  4. AGR2 Predicts Tamoxifen Resistance in Postmenopausal Breast Cancer Patients

    Directory of Open Access Journals (Sweden)

    Roman Hrstka

    2013-01-01

    Full Text Available Endocrine resistance is a significant problem in breast cancer treatment. Thus identification and validation of novel resistance determinants is important to improve treatment efficacy and patient outcome. In our work, AGR2 expression was determined by qRT-PCR in Tru-Cut needle biopsies from tamoxifen-treated postmenopausal breast cancer patients. Our results showed inversed association of AGR2 mRNA levels with primary treatment response (P=0.0011 and progression-free survival (P=0.0366 in 61 ER-positive breast carcinomas. As shown by our experimental and clinical evaluations, elevated AGR2 expression predicts decreased efficacy of tamoxifen treatment. From this perspective, AGR2 is a potential predictive biomarker enabling selection of an optimal algorithm for adjuvant hormonal therapy in postmenopausal ER-positive breast cancer patients.

  5. Processing and microstructural characterisation of a UO{sub 2}-based ceramic for disposal studies on spent AGR fuel

    Energy Technology Data Exchange (ETDEWEB)

    Hiezl, Z., E-mail: z.hiezl11@imperial.ac.uk [Department of Materials, Imperial College, London SW7 2AZ (United Kingdom); Hambley, D.I. [Spent Fuel Management and Disposal, UK National Nuclear Laboratory (NNL), Central Laboratory, Sellafield CA20 1PG (United Kingdom); Padovani, C. [Radioactive Waste Management Limited (formerly the Radioactive Waste Management Directorate of the Nuclear Decommissioning Authority), Harwell OX11 0RH (United Kingdom); Lee, W.E. [Department of Materials, Imperial College, London SW7 2AZ (United Kingdom)

    2015-01-15

    Preparation and characterisation of a Simulated Spent Nuclear Fuel (SIMFuel), which replicates the chemical state and microstructure of Spent Nuclear Fuel (SNF) discharged from a UK Advanced Gas-cooled Reactor (AGR) after a cooling time of 100 years is described. Given the relatively small differences in radionuclide inventory expected over longer time periods, the SIMFuel studied in this work is expected to be also representative of spent fuel after significantly longer periods (e.g. 1000 years). Thirteen stable elements were added to depleted UO{sub 2} and sintered to simulate the composition of fuel pellets after burn-ups of 25 and 43 GWd/tU and, as a reference, pure UO{sub 2} pellets were also investigated. The fission product distribution was calculated using the FISPIN code provided by the UK National Nuclear Laboratory. SIMFuel pellets were up to 92% dense and during the sintering process in H{sub 2} atmosphere Mo–Ru–Rh–Pd metallic precipitates and grey-phase ((Ba, Sr)(Zr, RE) O{sub 3} oxide precipitates) formed within the UO{sub 2} matrix. These secondary phases are present in real PWR and AGR SNF. Metallic precipitates are generally spherical and have submicron particle size (0.8 ± 0.7 μm). Spherical oxide precipitates in SIMFuel measured up to 30 μm in diameter, but no data were available in the public domain to compare this to AGR SNF. The grain size of actual AGR SNF (∼3–30 μm) is larger than that measured in AGR SIMFuel (∼2–5 μm)

  6. Processing and microstructural characterisation of a UO2-based ceramic for disposal studies on spent AGR fuel

    International Nuclear Information System (INIS)

    Preparation and characterisation of a Simulated Spent Nuclear Fuel (SIMFuel), which replicates the chemical state and microstructure of Spent Nuclear Fuel (SNF) discharged from a UK Advanced Gas-cooled Reactor (AGR) after a cooling time of 100 years is described. Given the relatively small differences in radionuclide inventory expected over longer time periods, the SIMFuel studied in this work is expected to be also representative of spent fuel after significantly longer periods (e.g. 1000 years). Thirteen stable elements were added to depleted UO2 and sintered to simulate the composition of fuel pellets after burn-ups of 25 and 43 GWd/tU and, as a reference, pure UO2 pellets were also investigated. The fission product distribution was calculated using the FISPIN code provided by the UK National Nuclear Laboratory. SIMFuel pellets were up to 92% dense and during the sintering process in H2 atmosphere Mo–Ru–Rh–Pd metallic precipitates and grey-phase ((Ba, Sr)(Zr, RE) O3 oxide precipitates) formed within the UO2 matrix. These secondary phases are present in real PWR and AGR SNF. Metallic precipitates are generally spherical and have submicron particle size (0.8 ± 0.7 μm). Spherical oxide precipitates in SIMFuel measured up to 30 μm in diameter, but no data were available in the public domain to compare this to AGR SNF. The grain size of actual AGR SNF (∼3–30 μm) is larger than that measured in AGR SIMFuel (∼2–5 μm)

  7. AGR2 Predicts Tamoxifen Resistance in Postmenopausal Breast Cancer Patients

    OpenAIRE

    Roman Hrstka; Veronika Brychtova; Pavel Fabian; Borivoj Vojtesek; Marek Svoboda

    2013-01-01

    Endocrine resistance is a significant problem in breast cancer treatment. Thus identification and validation of novel resistance determinants is important to improve treatment efficacy and patient outcome. In our work, AGR2 expression was determined by qRT-PCR in Tru-Cut needle biopsies from tamoxifen-treated postmenopausal breast cancer patients. Our results showed inversed association of AGR2 mRNA levels with primary treatment response (P = 0.0011) and progression-free survival (P = 0.0366)...

  8. Gas mixing processes in nuclear AGR boilers

    International Nuclear Information System (INIS)

    To ensure the safe operation and control of Nuclear (A.G.R.) boilers, 2-D computational models are currently under development. The aim of these models is to predict the flow and temperature distribution of the gas and water side under different operational conditions. These models are based on numerical solutions of the 2-D flow and heat transfer equations for turbulent flow in boilers. Measurements on a closely pitched tube bank with water cooling have demonstrated considerable discrepancies between experimental results and computer predictions. This investigation is therefore being carried out to study theoretically and experimentally the flow and heat transfer process under such a boiler condition. A two dimensional computer model has been developed which incorporates the effects of gas mixing and the interactions between the gas and water side. To cover the complete heat exchanger the governing equations are written in the lumped parameter form. The governing equations have been solved by a computer code written in FORTRAN-77. To test the validity of this model, the computer predictions have been compared with experimental results. Results to date indicate reasonable agreement with experiment and a further refinement of the computer model is indicated. (author)

  9. Heysham II/Torness AGR steam generator

    International Nuclear Information System (INIS)

    The AGR Steam Generators for Heysham II and Torness Power Stations have been installed at site and are being operated in the initial low temperature commissioning plant engineering tests. In this paper a description of the high pressure once-through steam generators together with layout arrangements, materials employed, operating parameters, plant operating conditions and constraints is given. An outline of the development of the design through thermo-hydraulic considerations, mechanical design, instrumentation to component testing is presented. Special features of the design directed to accommodate such requirements as seismic loadings, waterside static and dynamic stability, gas flow induced vibration, thermal expansions are described in detail. The fabrication facilities employed and techniques selected and developed for the manufacture and assembly of the heating surfaces are presented. These include welding processes, tube manipulation and heat treatment with details of the automation applied to the processes. Operating experience in the early commissioning plant engineering tests at Site is described with an emphasis on those tests which provide the final confirmation of the design prior to operation at full load. The paper concludes with a description of the outstanding commissioning activities up to raise power. (author)

  10. Reactor and fuel behaviour under severe transient conditions in WAGR

    International Nuclear Information System (INIS)

    The Windscale prototype advanced gas-cooled reactor (WAGR) closed down in 1981. Following the formal shutdown a collaborative series of safety related experiments were performed, jointly funded by the UKAEA, CEGB and SSEB. Reactor transient tests were carried out, simulating aspects of postulated CAGR faults under conditions far beyond those achievable on commercial plant. Modelling of these tests with a CAGR fault study code has shown that a high degree of confidence can be placed in the predictions of the code. The experiments also included pressurised high temperature transients on individual fuel stringers in a loop of the reactor, which were intended to take the fuel pin cladding close to melting. Post-irradiation examination of the fuel has confirmed the success of the experiments, demonstrating the durability of the present CAGR fuel design under such conditions. (author)

  11. AGR-3/4 Data Qualification Report for ATR Cycles 151A, 151B, 152A, 152B, 154A, and 154B

    Energy Technology Data Exchange (ETDEWEB)

    Binh T. Pham

    2014-02-01

    This data report provides the qualification status of Advanced Gas Reactor-3/4 (AGR-3/4) fuel irradiation experimental data from Advanced Test Reactor (ATR) Cycles 151A, 151B, 152A, 152B, 154A, and 154B, as recorded in the Nuclear Data Management and Analysis System (NDMAS). Of these cycles, ATR Cycle 152A is a low power cycle that occurred when the ATR core was briefly at low power. The irradiation data are not used for physics and thermal calculation, but the qualification status of these cycle data is still covered in this report. On the other hand, during ATR Cycles 153A (unplanned Outage cycle) and 153B (Power Axial Locator Mechanism [PALM] cycle), the AGR-3/4 was pulled out from the ATR core and stored in the canal to avoid being overheated. Therefore, qualification of the AGR-3/4 irradiation data from these 2 cycles was excluded in this report. By the end of ATR Cycle 154B, AGR-3/4 was irradiated for a total of 264.1 effective full power days. The AGR-3/4 data streams addressed in this report include thermocouple (TC) temperatures, sweep gas data (flow rates, pressure, and moisture content), and Fission Product Monitoring System (FPMS) data (release rates and release-to-birth rate ratios [R/Bs]) for each of the twelve capsules in the AGR-3/4 experiment. The final data qualification status for these data streams is determined by a Data Review Committee (DRC) composed of AGR technical leads, Sitewide Quality Assurance (QA), and NDMAS analysts. The DRC convened on February 12, 2014, reviewed the data acquisition process, and considered whether the data met the requirements for data collection as specified in QA-approved Very High Temperature Reactor (VHTR) Technology Development Office (TDO) data collection plans. The DRC also examined the results of NDMAS data testing and statistical analyses, and confirmed the qualification status of the data as given in this report.

  12. Operational and reliability experience with reactor instrumentation

    International Nuclear Information System (INIS)

    In the last 15 years the CEGB has experienced progressive plant development, integration and changes in operating regime through nine nuclear (gas-cooled reactor) power stations with corresponding instrumentation advances leading towards more refined centralized control. Operation and reliability experience with reactor instrumentation is reported in this paper with reference to the progressive changes related to the early magnox, late magnox and AGR periods. Data on instrumentation reliability in terms of reactor forced outages are presented and show that the instrumentation contributions to loss of generating plant availability are small. Reactor safety circuits, neutron flux and temperature measurements, gas analysis and vibration monitoring are discussed. In reviewing the reactor instrumentation the emphasis is on reporting recent experience, particularly on AGR equipment, but overall performance and changes to magnox equipment are included so that some appreciation can be obtained of instrumentation requirements with respect to plant lifetimes. (author)

  13. New insight into transmembrane topology of Staphylococcus aureus histidine kinase AgrC.

    Science.gov (United States)

    Wang, Lina; Quan, Chunshan; Xiong, Wen; Qu, Xiaojing; Fan, Shengdi; Hu, Wenzhong

    2014-03-01

    Staphylococcus aureus accessory gene regulator (agr) locus controls the expression of virulence factors through a classical two-component signal transduction system that consists of a receptor histidine protein kinase AgrC and a cytoplasmic response regulator AgrA. An autoinducing peptide (AIP) encoded by agr locus activates AgrC, which transduces extracellular signals into the cytoplasm. Despite extensive investigations to identify AgrC-AIP interaction sites, precise signal recognition mechanisms remain unknown. This study aims to clarify the membrane topology of AgrC by applying the green fluorescent protein (GFP) fusion technique and the substituted cysteine accessibility method (SCAM). However, our findings were inconsistent with profile obtained previously by alkaline phosphatase. We report the topology of AgrC shows seven transmembrane segments, a periplasmic N-terminus, and a cytoplasmic C-terminus. PMID:24361366

  14. AGROCOOP Tienda Online Cooperativas Agrícolas

    OpenAIRE

    Segura Rama, José Ignacio

    2016-01-01

    El presente Trabajo Fin de Master versa sobre la elaboración, creación, programación, diseño y puesta en marcha de una tienda online AVANZADA para cooperativas agrícolas, queremos mostrar como poder crear una tienda e-comerce para cooperativas agrícolas de nuestro País. Con ello queremos así abrir el mercado de estas, ademas de mostrar como usar un gran compendio de tecnologías. Vamos a agrupar y poner en común, un conjunto amplio de distintas técnicas de programación web, que ...

  15. Producción agrícola controlada

    OpenAIRE

    Abraham Rojano A.; Raquel Salazar M.; Álvaro Llamas G.

    2004-01-01

    A diferencia de la producción de bienes industriales donde se puede trabajar día y noche y en diferentes lugares al mismo tiempo, la producción agrícola tiene componentes físicos y químicos en interacción con componentes vivos. Los factores físicos y químicos son factibles de trabajar con enfoques industriales de acuerdo a las reglas básicas del control; sin embargo, el componente vivo de la producción agrícola esta condicionado hasta la fecha por un proceso ineludible: la foto...

  16. Fabrication and Comparison of Fuels for Advanced Gas Reactor Irradiation Tests

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey Phillips; Charles Barnes; John Hunn

    2010-10-01

    As part of the program to demonstrate TRISO-coated fuel for the Next Generation Nuclear Plant, a series of irradiation tests of Advanced Gas Reactor (AGR) fuel are being performed in the Advanced Test Reactor (ATR) at the Idaho National Laboratory. In the first test, called “AGR-1,” graphite compacts containing approximately 300,000 coated particles were irradiated from December 2006 until November 2009. Development of AGR-1 fuel sought to replicate the properties of German TRISO-coated particles. No particle failures were seen in the nearly 3-year irradiation to a burn up of 19%. The AGR-1 particles were coated in a two-inch diameter coater. Following fabrication of AGR-1 fuel, process improvements and changes were made in each of the fabrication processes. Changes in the kernel fabrication process included replacing the carbon black powder feed with a surface-modified carbon slurry and shortening the sintering schedule. AGR-2 TRISO particles were produced in a six-inch diameter coater using a change size about twenty-one times that of the two-inch diameter coater used to coat AGR-1 particles. Changes were also made in the compacting process, including increasing the temperature and pressure of pressing and using a different type of press. Irradiation of AGR-2 fuel began in late spring 2010. Properties of AGR-2 fuel compare favorably with AGR-1 and historic German fuel. Kernels are more homogeneous in shape, chemistry and density. TRISO-particle sphericity, layer thickness standard deviations, and defect fractions are also comparable. In a sample of 317,000 particles from deconsolidated AGR-2 compacts, 3 exposed kernels were found in a leach test. No SiC defects were found in a sample of 250,000 deconsolidated particles, and no IPyC defects in a sample of 64,000 particles. The primary difference in properties between AGR-1 and AGR-2 compacts is that AGR-2 compacts have a higher matrix density, 1.6 g/cm3 compared to about 1.3 g/cm3 for AGR-1 compacts. Based on

  17. Fabrication and Comparison of Fuels for Advanced Gas Reactor Irradiation Tests

    International Nuclear Information System (INIS)

    As part of the program to demonstrate TRISO-coated fuel for the Next Generation Nuclear Plant, a series of irradiation tests of Advanced Gas Reactor (AGR) fuel are being performed in the Advanced Test Reactor (ATR) at the Idaho National Laboratory. In the first test, called 'AGR-1,' graphite compacts containing approximately 300,000 coated particles were irradiated from December 2006 until November 2009. Development of AGR-1 fuel sought to replicate the properties of German TRISO-coated particles. No particle failures were seen in the nearly 3-year irradiation to a burn up of 19%. The AGR-1 particles were coated in a two-inch diameter coater. Following fabrication of AGR-1 fuel, process improvements and changes were made in each of the fabrication processes. Changes in the kernel fabrication process included replacing the carbon black powder feed with a surface-modified carbon slurry and shortening the sintering schedule. AGR-2 TRISO particles were produced in a six-inch diameter coater using a change size about twenty-one times that of the two-inch diameter coater used to coat AGR-1 particles. Changes were also made in the compacting process, including increasing the temperature and pressure of pressing and using a different type of press. Irradiation of AGR-2 fuel began in late spring 2010. Properties of AGR-2 fuel compare favorably with AGR-1 and historic German fuel. Kernels are more homogeneous in shape, chemistry and density. TRISO-particle sphericity, layer thickness standard deviations, and defect fractions are also comparable. In a sample of 317,000 particles from deconsolidated AGR-2 compacts, 3 exposed kernels were found in a leach test. No SiC defects were found in a sample of 250,000 deconsolidated particles, and no IPyC defects in a sample of 64,000 particles. The primary difference in properties between AGR-1 and AGR-2 compacts is that AGR-2 compacts have a higher matrix density, 1.6 g/cm3 compared to about 1.3 g/cm3 for AGR-1 compacts. Based on fuel

  18. Analysis of Fission Products on the AGR-1 Capsule Components

    Energy Technology Data Exchange (ETDEWEB)

    Paul A. Demkowicz; Jason M. Harp; Philip L. Winston; Scott A. Ploger

    2013-03-01

    The components of the AGR-1 irradiation capsules were analyzed to determine the retained inventory of fission products in order to determine the extent of in-pile fission product release from the fuel compacts. This includes analysis of (i) the metal capsule components, (ii) the graphite fuel holders, (iii) the graphite spacers, and (iv) the gas exit lines. The fission products most prevalent in the components were Ag-110m, Cs 134, Cs 137, Eu-154, and Sr 90, and the most common location was the metal capsule components and the graphite fuel holders. Gamma scanning of the graphite fuel holders was also performed to determine spatial distribution of Ag-110m and radiocesium. Silver was released from the fuel components in significant fractions. The total Ag-110m inventory found in the capsules ranged from 1.2×10 2 (Capsule 3) to 3.8×10 1 (Capsule 6). Ag-110m was not distributed evenly in the graphite fuel holders, but tended to concentrate at the axial ends of the graphite holders in Capsules 1 and 6 (located at the top and bottom of the test train) and near the axial center in Capsules 2, 3, and 5 (in the center of the test train). The Ag-110m further tended to be concentrated around fuel stacks 1 and 3, the two stacks facing the ATR reactor core and location of higher burnup, neutron fluence, and temperatures compared with Stack 2. Detailed correlation of silver release with fuel type and irradiation temperatures is problematic at the capsule level due to the large range of temperatures experienced by individual fuel compacts in each capsule. A comprehensive Ag 110m mass balance for the capsules was performed using measured inventories of individual compacts and the inventory on the capsule components. For most capsules, the mass balance was within 11% of the predicted inventory. The Ag-110m release from individual compacts often exhibited a very large range within a particular capsule.

  19. Anisotropie d'agrégats de cobalt

    OpenAIRE

    Morel, Robert

    2009-01-01

    Ce mémoire présente une revue sur la croissance d'agrégats de cobalt par condensation en phase gazeuse. Suit une revue des différent mécanismes physiques à l'origine de l'anisotropie magnétique du cobalt, et de leurs manifestations dans des particules nanométriques.

  20. El Ingeniero Agrícola en la Agroindustria

    Directory of Open Access Journals (Sweden)

    Ramos Sarria Ramiro

    1985-12-01

    Full Text Available En este artículo se da a conocer la capacidad técnica y administrativa que posee el Ingeniero Agrícola, para organizar un sistema coherente que logre definir, planificar y promover una política de desarrollo científico y tecnológico en la agroindustria.

  1. Producción agrícola controlada

    Directory of Open Access Journals (Sweden)

    Abraham Rojano A.

    2004-01-01

    Full Text Available A diferencia de la producción de bienes industriales donde se puede trabajar día y noche y en diferentes lugares al mismo tiempo, la producción agrícola tiene componentes físicos y químicos en interacción con componentes vivos. Los factores físicos y químicos son factibles de trabajar con enfoques industriales de acuerdo a las reglas básicas del control; sin embargo, el componente vivo de la producción agrícola esta condicionado hasta la fecha por un proceso ineludible: la fotosíntesis. Esto es, una vez que el proceso agrícola inicia, se puede jugar un poco con las variables en el transcurso, sin embargo el final es inevitable como parte de una ley fundamental del ciclo natural, i.e., nacer, crecer, reproducir y morir. Por lo tanto, el proceso agrícola, a grandes rasgos presenta el reto de controlar: a variables físicas y químicas como función de espacio y tiempo tales como temperatura, humedad, luz, conductividad eléctrica, pH, concentraciones de CO2, relación de actividad fotosintética (PAR, entre otras; y b variables biológicas como el crecimiento, la producción de biomasa, y transpiración efectiva. Aun mas, el control de las variables mencionadas lleva consigo el desafió de mantener la producción agrícola dentro del campo de la ética y de las restricciones del mercado.

  2. Differential expression of anterior gradient gene AGR2 in prostate cancer

    International Nuclear Information System (INIS)

    The protein AGR2 is a putative member of the protein disulfide isomerase family and was first identified as a homolog of the Xenopus laevis gene XAG-2. AGR2 has been implicated in a number of human cancers. In particular, AGR2 has previously been found to be one of several genes that encode secreted proteins showing increased expression in prostate cancer cells compared to normal prostatic epithelium. Gene expression levels of AGR2 were examined in prostate cancer cells by microarray analysis. We further examined the relationship of AGR2 protein expression to histopathology and prostate cancer outcome on a population basis using tissue microarray technology. At the RNA and protein level, there was an increase in AGR2 expression in adenocarcinoma of the prostate compared to morphologically normal prostatic glandular epithelium. Using a tissue microarray, this enhanced AGR2 expression was seen as early as premalignant PIN lesions. Interestingly, within adenocarcinoma samples, there was a slight trend toward lower levels of AGR2 with increasing Gleason score. Consistent with this, relatively lower levels of AGR2 were highly predictive of disease recurrence in patients who had originally presented with high-stage primary prostate cancer (P = 0.009). We have shown for the first time that despite an increase in AGR2 expression in prostate cancer compared to non-malignant cells, relatively lower levels of AGR2 are highly predictive of disease recurrence following radical prostatectomy

  3. Need for USA high level waste (HLW) alternate geological repository (AGR) and for a different methodology to enhance its acceptance

    International Nuclear Information System (INIS)

    In early February 2010, the administration stopped work and withdrew the Department of Energy (DOE) application for a construction permit for the Yucca Mountain geological repository from the Nuclear Regulatory Commission (NRC). Also, a 'blue ribbon' Commission was appointed to explore alternatives for storage, processing, and disposal, including evaluation of advanced fuel cycles and to provide a final report in 24 months. That decision, however, failed to recognize that: (1) the U.S. will need an early alternate geological repository (AGR) for its HLW irrespective of the findings of the 'blue ribbon' Commission; (2) the once-through spent fuel inventory from commercial nuclear power reactors will continue to rise and so will the damages against the government for its failure to remove spent fuel from reactors sites, as specified in contracts; (3) there are prepackaged DOE and nuclear weapons HLW ready for shipment to a repository which must be taken into account because of government penalties for failure to do so; (4) the current Nuclear Waste Policy Act (NWPA) needs to be modified to allow the early search and approval of Alternate Geological Repository (AGR) and for an interim centralized HLW storage facility to reduce government liabilities; and (5) the methodology used to license Yucca Mountain needs to undergo serious modifications, including a different non-politicized management and siting credo. This paper reviews and discusses all the preceding shortcomings and proposes significant changes to pursue AGR as soon as possible and to get site approval by the NRC first under a formal, stepwise, well-structured risk-informed decision approach as recommended.

  4. Optical techniques for nuclear reactor inspection

    International Nuclear Information System (INIS)

    Optical inspection techniques available and relevant to the various stages of the life cycle of a nuclear reactor are briefly reviewed. Experience in the three main types of nuclear reactor of interest to the CEGB, Magnox, AGR and PWR, is discussed. Conventional optical systems and stereoscopic viewing systems are described together with specialized and novel techniques, mainly Marchwood Engineering Laboratory's developments, which have proved valuable in tackling a variety of inspection problems. (U.K.)

  5. The identification of an homogenous critical group using statistical extreme-value theory: application to laverbread consumers and the Windscale effluent discharges

    International Nuclear Information System (INIS)

    The International Commission of Radiological Protection states that a critical group should be representative of those individuals in the population expected to receive the highest dose. The appropriate dose limit should then be applied to the mean dose of this group. The edible seaweed Porphyra (laverbread) has been identified as the link in the critical exposure pathway limiting discharges of controlled low-level radioactive liquid waste from Windscale. The frequency distributions of the largest values of samples of 10, 20, 30, 40 and 50 male and female, child and adult consumers of laverbread are determined from the parent distributions by Monte Carlo sampling methods. From these results the extreme-value distribution of adult males of samples of 30 is taken to be a good estimate of the critical group, from which the median consumption rate of laverbread consumed per day is 55 g. The annual collective organ dose delivered to the lower large intestine of the total laverbread consumer group is estimated to be 266 man-rem. (author)

  6. The Windscale inquiry. Report by the Hon. Justice Parker, presented to the Secretary of State for the Environment on 26 January 1978

    International Nuclear Information System (INIS)

    This Volume I contains the official Report by the Inspector appointed to conduct a local enquiry for the purpose of hearing objections and representations relating to an application by British Nuclear Fuels Limited for planning permission for a plant for reprocessing irradiated oxide nuclear fuels and support services at their Windscale and Calder Works. The report falls under the following headings: introduction; essential background; history of the application; scope of the Inquiry; summary of contentions and structure of the report; the nuclear weapons proliferation question; terrorism and civil liberties; the need for reprocessing of oxide fuel and relationship to the FBR question; financial aspects; routine discharges - risks; risks - accidents; size of plant; public hostility; conventional planning issues; the Inquiry itself; overall conclusion and recommendation; summary of principal conclusions and recommendations; miscellaneous matters. The volume also contains three of the five Annexes to the Report: Annex 3 - somatic risk estimates; Annex 4 - genetic risk estimates; and Annex 5 - mean genetic dose to local population. (Annex 1 - list of appearances and Annex 2 - list of documents, are contained in Volume 2, and the Index to the Report is Volume 3). (U.K.)

  7. The behaviour of defected AGR fuel pins during water storage

    International Nuclear Information System (INIS)

    Results are presented of measurements made on the release of radioactivity to simulated Board AGR pond water from irradiated CAGR fuel pins, which have suspected genuine or artificially induced clad defects. Six fuel pins have been examined, one having the top end cap removed, two having suspected end cap defects and three with a 1 mm hole pierced through the clad; two of these three latter pins were only partially immersed and had the end cap in the gas space removed. The work completes the first phase of a series of experiments carried out at AEE Winfrith to gain an understanding of the behaviour of defective AGR fuel pins during aqueous storage. Data are given on the release fractions found for Cs-137, Sr-90, Ru-106, Sb-125 and Ce-144. Analytical data from earlier experiments which have recently become available are also presented. (U.K.)

  8. An Assessment of ORNL PIE Capabilities for the AGR Program Capsule Post Irradiation Examination

    Energy Technology Data Exchange (ETDEWEB)

    Morris, Robert Noel [ORNL

    2006-09-01

    ORNL has facilities and experienced staff that can execute +the Advanced Gas Reactor (AGR) Post Irradiation Examination (PIE) task. While the specific PIE breakdown needs to be more formally defined, the basic outline is clear and the existing capabilities can be assessed within the needs of the tasks defined in the program plan. A one-to-one correspondence between the program plan tasks and the current ORNL PIE status was conducted and while some shortcomings were identified, the general capability is available. Specific upgrade needs were identified and reviewed. A path forward was formulated. Building 3525 is available for this work and this building is currently receiving renewed attention from management so that it will be in good working order prior to the expected PIE start date. This building is equipped with the tools necessary for PIEs of this nature, but the long hiatus in coated particle fuel work has left it with aging analysis tools. This report identified several of these tools and rough estimates of what would be required to update and replace them. In addition, other ORNL buildings are available to support Building 3525 in specialized tasks along with the normal laboratory infrastructure. Before the AGR management embarks on any equipment development effort, the PIE tasks should be updated against current program (modeling and data) needs and better defined so that the items to be measured, their measurement uncertainties, and thru-put needs can be reviewed. A Data Task Matrix (DTM) should be prepared so that the program data needs can be compared against the identified PIE tasks and what is practical in the hot cell environment to make sure nothing is overlooked. Finally, thought should be given to the development of standardized equipment designs between sites to avoid redundant design efforts and different measurement techniques. This is a potentially cost saving effort that can also avoid data inconsistencies.

  9. Trabajadores agrícolas y subjetividad en California

    Directory of Open Access Journals (Sweden)

    Florencio Posadas Segura

    2014-01-01

    Full Text Available En este trabajo se explora el problema de la subjetividad de los trabajadores agríco - las, partiendo de la hipótesis de que éstos consideran malas sus condiciones de vida y de trabajo. Mediante el trabajo de campo se demostraron sus conocimientos y opi - niones sobre su situación laboral y existencial en el Valle de San Joaquín California durante 2007 y 2008. Se descubrió que la visión del trabajador agrícola está basada en la subjetivación y reinterpretación de sus circunstancias objetivas de trabajo y de vida. Se concluyó que los trabajadores agrícolas opinan que sus condiciones son pé - simas porque sus derechos laborales, sociales y humanos no se reconocen o respetan, la crisis económica, social y política de Estados Unidos les perjudica y el Tratado de Libre Comercio entre México, Estados Unidos y Canadá ( TLCAN sólo podría beneficiarles con una reforma migratoria.

  10. Lessons Learned From Gen I Carbon Dioxide Cooled Reactors

    Energy Technology Data Exchange (ETDEWEB)

    David E. Shropshire

    2004-04-01

    This paper provides a review of early gas cooled reactors including the Magnox reactors originating in the United Kingdom and the subsequent development of the Advanced Gas-cooled Reactors (AGR). These early gas cooled reactors shared a common coolant medium, namely carbon dioxide (CO2). A framework of information is provided about these early reactors and identifies unique problems/opportunities associated with use of CO2 as a coolant. Reactor designers successfully rose to these challenges. After years of successful use of the CO2 gas cooled reactors in Europe, the succeeding generation of reactors, called the High Temperature Gas Reactors (HTGR), were designed with Helium gas as the coolant. Again, in the 21st century, with the latest reactor designs under investigation in Generation IV, there is a revived interest in developing Gas Cooled Fast Reactors that use CO2 as the reactor coolant. This paper provides a historical perspective on the 52 CO2 reactors and the reactor programs that developed them. The Magnox and AGR design features and safety characteristics were reviewed, as well as the technologies associated with fuel storage, reprocessing, and disposal. Lessons-learned from these programs are noted to benefit the designs of future generations of gas cooled nuclear reactors.

  11. Lessons learned from Gen-I carbon dioxide cooled reactors

    International Nuclear Information System (INIS)

    This paper provides a review of early gas cooled reactors including the Magnox reactors originating in the United Kingdom and the subsequent development of the Advanced Gas-cooled Reactors (AGR). These early gas cooled reactors shared a common coolant medium, namely carbon dioxide (CO2). A framework of information is provided about these early reactors and identifies unique problems/opportunities associated with use of CO2 as a coolant. Reactor designers successfully rose to these challenges. After years of successful use of the CO2 gas cooled reactors in Europe, the succeeding generation of reactors, called the High Temperature Gas Reactors (HTGR), were designed with Helium gas as the coolant. Again, in the 21. century, with the latest reactor designs under investigation in Generation IV, there is a revived interest in developing Gas Cooled Fast Reactors that use CO2 as the reactor coolant. This paper provides a historical perspective on the 52 CO2 reactors and the reactor programs that developed them. The Magnox and AGR design features and safety characteristics were reviewed, as well as the technologies associated with fuel storage, reprocessing, and disposal. Lessons-learned from these programs are noted to benefit the designs of future generations of gas cooled nuclear reactors. (author)

  12. The roles of water addition and gas composition in AGR accident management

    International Nuclear Information System (INIS)

    Severe Accident Guidelines (SAGs) are being produced in line with best international practice for managing a severe accident in an AGR. Such an accident would be extremely unlikely due to the long timescales for recovery prior to core damage. A number of actions proposed in the SAGs are concerned with the prevention of air ingress and the deliberate injection of water into the core. Air ingress is minimized by sealing breaches and by the controlled injection of inert gases into the vessel, although at high temperatures the change in reactor gas from CO2 to CO provides a more inert atmosphere and reduces any ingressing oxygen. Consideration would be given to the injection of water into the core if the installed cooling systems could not be recovered sufficiently in a direct or improvised manner. In such cases sufficient cooling should be possible by injecting water uniformly across the core into a few tens of channels. Ideally the water would be injected before significant fission product release had occurred and before the graphite had become hot enough to oxidise in steam. This advice is reinforced by experiments with a simulated fuel pin in the presence of reactor graphite which showed that fission products released from the pin could be transported on fine (0.1 μm) graphite aerosols. (author). 4 refs, 6 figs

  13. Dynamic fracture effects on remote stress amplification in AGR graphite bricks

    International Nuclear Information System (INIS)

    During service, AGR graphite moderator bricks degrade due to the reactor environment; leading to a internal stress 'turn-around'. Prompt secondary cracking (PSC) might be caused by the combination of a cantilever effect and the dynamic stress superposition of a propagating crack which is likely to initiate after stress turn around. In order to access the lifespan of these critical components and phenomena affects, a newly implemented modelling technique in EDF's Code-Aster, known as extended Finite Element Method with cohesive zones (XCZM) has been utilised to investigate strain wave stress amplification. XCZM was used on 3 tetrahedral meshed 2D graphite brick like geometries: one without defects, one with a 'methane hole' 1/3 along the crack paths and another with a crack 2/3 along the crack paths. The crack paths were assumed to be straight to enable direct comparison. The results showed that a secondary crack was found to be initiated by the dynamic effects of the primary crack directly opposite, which was on top of the static cantilever stress increase. It was also shown that a 'methane hole' 2/3 along the primary crack path was found to arrest a crack and the dynamic material response subsequently reinitiating it. This may have consequences when interpreting crack profiles and positions in reactor outages

  14. Agricultura, questao agrária e reforma agrária no Brasil do século XX

    OpenAIRE

    Sonia Regina de Mendonça

    2003-01-01

    Este trabalho tem início com uma indagação: por que tem sido tão freqüente, no meio acadêmico e na produção historiográfica brasileira, durante anos recentes, a falta de clareza com que são tratados significantes tão distintos quanto “reforma agrária” e “questão agrária”? Recordando, com base em Pierre Bourdieu, que o poder simbólico consegue transformar relações de dominação/submissão, em relações afetivas e, mais ainda, que quanto maior o sentimento mobilizado, maior é o grau de ocultamento...

  15. An analysis of nuclear fuel burnup in the AGR-1 TRISO fuel experiment using gamma spectrometry, mass spectrometry, and computational simulation techniques

    International Nuclear Information System (INIS)

    Highlights: • The burnup of irradiated AGR-1 TRISO fuel was analyzed using gamma spectrometry. • The burnup of irradiated AGR-1 TRISO fuel was also analyzed using mass spectrometry. • Agreement between experimental results and neutron physics simulations was excellent. - Abstract: AGR-1 was the first in a series of experiments designed to test US TRISO fuel under high temperature gas-cooled reactor irradiation conditions. This experiment was irradiated in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) and is currently undergoing post-irradiation examination (PIE) at INL and Oak Ridge National Laboratory. One component of the AGR-1 PIE is the experimental evaluation of the burnup of the fuel by two separate techniques. Gamma spectrometry was used to non-destructively evaluate the burnup of all 72 of the TRISO fuel compacts that comprised the AGR-1 experiment. Two methods for evaluating burnup by gamma spectrometry were developed, one based on the Cs-137 activity and the other based on the ratio of Cs-134 and Cs-137 activities. Burnup values determined from both methods compared well with the values predicted from simulations. The highest measured burnup was 20.1% FIMA (fissions per initial heavy metal atom) for the direct method and 20.0% FIMA for the ratio method (compared to 19.56% FIMA from simulations). An advantage of the ratio method is that the burnup of the cylindrical fuel compacts can be determined in small (2.5 mm) axial increments and an axial burnup profile can be produced. Destructive chemical analysis by inductively coupled mass spectrometry (ICP-MS) was then performed on selected compacts that were representative of the expected range of fuel burnups in the experiment to compare with the burnup values determined by gamma spectrometry. The compacts analyzed by mass spectrometry had a burnup range of 19.3% FIMA to 10.7% FIMA. The mass spectrometry evaluation of burnup for the four compacts agreed well with the gamma

  16. Advanced gas cooled reactors - Designing for safety

    International Nuclear Information System (INIS)

    The Advanced Gas-Cooled Reactor Power Stations recently completed at Heysham in Lancashire, England, and Torness in East Lothian, Scotland represent the current stage of development of the commercial AGR. Each power station has two reactor turbo-generator units designed for a total station output of 2x660 MW(e) gross although powers in excess of this have been achieved and it is currently intended to uprate this as far as possible. The design of both stations has been based on the successful operating AGRs at Hinkley Point and Hunterston which have now been in-service for almost 15 years, although minor changes were made to meet new safety requirements and to make improvements suggested by operating experience. The construction of these new AGRs has been to programme and within budget. Full commercial load for the first reactor at Torness was achieved in August 1988 with the other three reactors following over the subsequent 15 months. This paper summarises the safety principles and guidelines for the design of the reactors and discusses how some of the main features of the safety case meet these safety requirements. The paper also summarises the design problems which arose during the construction period and explains how these problems were solved with the minimum delay to programme

  17. Regulation of protein A synthesis by the sar and agr loci of Staphylococcus aureus.

    OpenAIRE

    Cheung, A L; Eberhardt, K.; Heinrichs, J H

    1997-01-01

    The synthesis of protein A in Staphylococcus aureus is regulated by global regulatory loci such as sar and agr. Phenotypic data indicate that both sar and agr suppress protein A synthesis; like agr, sar also regulates protein A production at the transcriptional level. To determine the genetic requirement of sar in protein A suppression, we transformed shuttle plasmids containing various sar fragments into a sar mutant. Our results indicated that the 560-bp sarA transcript, or, more probably, ...

  18. Design and Expected Performance of the AGR-1 Fission Product Monitoring System (FPMS)

    Energy Technology Data Exchange (ETDEWEB)

    John K. (Jack) Hartwell; Dawn M. Scates

    2005-09-01

    The effluent from each test capsule of the AGR-1 experiment will be monitored by a detector system consisting of a gamma-ray spectrometer and a gross radiation detector. This collection of radiation measurement systems will be known as the AGR-1 Fission Product Monitoring System (FPMS). Proper design and functioning of the FPMS is critical to the success of the AGR-1 fuel test experiment.This document describes the AGR-1 FPMS and presents calculations indicating that this design will meet the pertinent test requirements.

  19. A review of CAGR fuel performance

    International Nuclear Information System (INIS)

    The performance of CAGR fuel in the Board's reactors is reviewed in the light of operating experience and the post-irradiation examination assessments which have been carried out. The results show that the extrapolation of the design from the Windscale AGR prototype has been very successful. Future trends in fuel design in order to achieve the higher burn-up targets now being specified are discussed. (author)

  20. A review of CAGR fuel performance

    International Nuclear Information System (INIS)

    The performance of CAGR fuel in the Electricity Board's reactors is reviewed in the light of operating experience and the post-irradiation examination assessments which have been carried out. The results show that the extrapolation of the design from the Windscale AGR prototype has been very successful. Future trends in fuel design in order to achieve the higher burn-up targets now being specified are discussed. (author)

  1. Ceramographic Examinations of Irradiated AGR-1 Fuel Compacts

    Energy Technology Data Exchange (ETDEWEB)

    Paul Demkowicz; Scott Ploger; John Hunn

    2012-05-01

    The AGR 1 experiment involved irradiating 72 cylindrical fuel compacts containing tri-structural isotropic (TRISO)-coated particles to a peak burnup of 19.5% fissions per initial metal atom with no in-pile failures observed out of almost 300,000 particles. Five irradiated AGR 1 fuel compacts were selected for microscopy that span a range of irradiation conditions (temperature, burnup, and fast fluence). These five compacts also included all four TRISO coating variations irradiated in the AGR experiment. The five compacts were cross-sectioned both transversely and longitudinally, mounted, ground, and polished after development of careful techniques for preserving particle structures against preparation damage. Approximately 40 to 80 particles within each cross section were exposed near enough to mid-plane for optical microscopy of kernel, buffer, and coating behavior. The microstructural analysis focused on kernel swelling and porosity, buffer densification and fracture, debonding between the buffer and inner pyrolytic carbon (IPyC) layers, and fractures in the IPyC and SiC layers. Three basic particle morphologies were established according to the extent of bonding between the buffer and IPyC layers: complete debonding along the interface (Type A), no debonding along the interface (Type B), and partial debonding (Type AB). These basic morphologies were subdivided according to whether the buffer stayed intact or fractured. The resulting six characteristic morphologies were used to classify particles within each cross section, but no spatial patterns were clearly observed in any of the cross-sectional morphology maps. Although positions of particle types appeared random within compacts, examining a total of 830 classified particles allowed other relationships among morphological types to be established.

  2. Microscopic analysis of irradiated AGR-1 coated particle fuel compacts

    Energy Technology Data Exchange (ETDEWEB)

    Scott Ploger; Paul Demkowicz; John Hunn; Robert Morris

    2012-10-01

    The AGR-1 experiment involved irradiation of 72 TRISO-coated particle fuel compacts to a peak burnup of 19.5% FIMA with no in-pile failures observed out of 3×105 total particles. Irradiated AGR-1 fuel compacts have been cross-sectioned and analyzed with optical microscopy to characterize kernel, buffer, and coating behavior. Five compacts have been examined so far, spanning a range of irradiation conditions (burnup, fast fluence, and irradiation temperature) and including all four TRISO coating variations irradiated in the AGR-1 experiment. The cylindrical specimens were sectioned both transversely and longitudinally, then polished to expose between approximately 40-80 individual particles on each mount. The analysis focused primarily on kernel swelling and porosity, buffer densification and fracturing, buffer-IPyC debonding, and fractures in the IPyC and SiC layers. Characteristic morphologies have been identified, over 800 particles have been classified, and spatial distributions of particle types have been mapped. No significant spatial patterns were discovered in these cross sections. However, some trends were found between morphological types and certain behavioral aspects. Buffer fractures were found in approximately 23% of the particles, and these fractures often resulted in unconstrained kernel swelling into the open cavities. Fractured buffers and buffers that stayed bonded to IPyC layers appear related to larger pore size in kernels. Buffer-IPyC interface integrity evidently factored into initiation of rare IPyC fractures. Fractures through part of the SiC layer were found in only three particles, all in conjunction with IPyC-SiC debonding. Compiled results suggest that the deliberate coating fabrication variations influenced the frequencies of IPyC fractures, IPyC-SiC debonds, and SiC fractures.

  3. Ceramographic Examinations of Irradiated AGR-1 Fuel Compacts

    Energy Technology Data Exchange (ETDEWEB)

    Paul Demkowicz; Scott Ploger; John Hunn; Jay S. Kehn

    2012-09-01

    The AGR 1 experiment involved irradiating 72 cylindrical fuel compacts containing tri-structural isotropic (TRISO)-coated particles to a peak burnup of 19.5% fissions per initial metal atom with no in-pile failures observed out of almost 300,000 particles. Six irradiated AGR 1 fuel compacts were selected for microscopy that span a range of irradiation conditions (temperature, burnup, and fast fluence). These six compacts also included all four TRISO coating variations irradiated in the AGR experiment. The six compacts were cross-sectioned both transversely and longitudinally, mounted, ground, and polished after development of careful techniques for preserving particle structures against preparation damage. From 36 to 79 particles within each cross section were exposed near enough to midplane for optical microscopy of kernel, buffer, and coating behavior. The microstructural analysis focused on kernel swelling and porosity, buffer densification and fracture, debonding between the buffer and inner pyrolytic carbon (IPyC) layers, and fractures in the IPyC and SiC layers. Three basic particle morphologies were established according to the extent of bonding between the buffer and IPyC layers: complete debonding along the interface (Type A), no debonding along the interface (Type B), and partial debonding (Type AB). These basic morphologies were subdivided according to whether the buffer stayed intact or fractured. The resulting six characteristic morphologies were used to classify particles within each cross section, but no spatial patterns were clearly observed in any of the cross-sectional morphology maps. Although positions of particle types appeared random within compacts, examining a total of 931 classified particles allowed other relationships among morphological types to be established.

  4. AGR-2 Final Data Qualification Report for U.S. Capsules - ATR Cycles 147A Through 154B

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Binh T; Einerson, Jeffrey J

    2014-07-01

    This report provides the data qualification status of AGR-2 fuel irradiation experimental data in four U.S. capsules from all 15 Advanced Test Reactor (ATR) Cycles 147A, 148A, 148B, 149A, 149B, 150A, 150B, 151A, 151B, 152A, 152B, 153A, 153B, 154A, and 154B, as recorded in the Nuclear Data Management and Analysis System (NDMAS). Thus, this report covers data qualification status for the entire AGR-2 irradiation and will replace four previously issued AGR-2 data qualification reports (e.g., INL/EXT-11-22798, INL/EXT-12-26184, INL/EXT-13-29701, and INL/EXT-13-30750). During AGR-2 irradiation, two cycles, 152A and 153A, occurred when the ATR core was briefly at low power, so AGR-2 irradiation data are not used for physics and thermal calculations. Also, two cycles, 150A and 153B, are Power Axial Locator Mechanism (PALM) cycles when the ATR power is higher than during normal cycles. During the first PALM cycle, 150A, the experiment was temporarily moved from the B-12 location to the ATR water canal and during the second PALM cycle, 153B, the experiment was temporarily moved from the B-12 location to the I-24 location to avoid being overheated. During the “Outage” cycle, 153A, seven flow meters were installed downstream from seven Fission Product Monitoring System (FPMS) monitors to measure flows from the monitors and these data are included in the NDMAS database. The AGR-2 data streams addressed in this report include thermocouple (TC) temperatures, sweep gas data (flow rates including new FPM downstream flows, pressure, and moisture content), and FPMS data (release rates and release-to-birth rate ratios [R/Bs]) for each of the four U.S. capsules in the AGR-2 experiment (Capsules 2, 3, 5, and 6). The final data qualification status for these data streams is determined by a Data Review Committee comprised of AGR technical leads, Very High Temperature Reactor (VHTR) Program Quality Assurance (QA), and NDMAS analysts. The Data Review Committee, which convened just

  5. Modelling of radiolytically corroded commercial AGR graphite fuel bricks

    International Nuclear Information System (INIS)

    Profiling of cross-sectional slices taken from a commercial AGR(CAGR) moderator fuel brick provides a method for modelling graphite property changes associated with radiolytic corrosion. A measure of the change in overall brick strength can be obtained by loading to failure the profiled slice under simulated loaded-core conditions. The application of this technique to predict the behaviour of radiolytically corroded CAGR fuel bricks is described. The effect on brick strength of different corrosion profiles, which result from exposure in different coolant gas mixtures, is examined and a simple relationship between strength and an expression describing the corrosion profile derived. (author)

  6. Design of the Advanced Gas Reactor Fuel Experiments for Irradiation in the Advanced Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    S. Blaine Grover

    2005-10-01

    The United States Department of Energy’s Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating eight particle fuel tests in the Advanced Test Reactor (ATR) located at the newly formed Idaho National Laboratory (INL) to support development of the next generation Very High Temperature Reactor (VHTR) in the United States. The ATR has a long history of irradiation testing in support of reactor development and the INL has been designated as the new United States Department of Energy’s lead laboratory for nuclear energy development. These AGR fuel experiments will be irradiated over the next ten years to demonstrate and qualify new particle fuel for use in high temperature gas reactors. The experiments will be irradiated in an inert sweep gas atmosphere with on-line temperature monitoring and control combined with on-line fission product monitoring of the sweep gas. The final design phase has just been completed on the first experiment (AGR-1) in this series and the support systems and fission product monitoring system that will monitor and control the experiment during irradiation. This paper discusses the development of the experimental hardware and support system designs and the status of the experiment.

  7. Rapid Staphylococcus aureus agr Type Determination by a Novel Multiplex Real-Time Quantitative PCR Assay

    OpenAIRE

    Francois, Patrice; Koessler, Thibaud; Huyghe, Antoine; Harbarth, Stephan; Bento, Manuela; Lew, Daniel; Etienne, Jérôme; Pittet, Didier; Schrenzel, Jacques

    2006-01-01

    The accessory gene regulator (agr) is a crucial regulatory component of Staphylococcus aureus involved in the control of bacterial virulence factor expression. We developed a real-time multiplex quantitative PCR assay for the rapid determination of S. aureus agr type. This assay represents a rapid and affordable alternative to sequence-based strategies for assessing relevant epidemiological information.

  8. Rapid Staphylococcus aureus agr type determination by a novel multiplex real-time quantitative PCR assay.

    Science.gov (United States)

    Francois, Patrice; Koessler, Thibaud; Huyghe, Antoine; Harbarth, Stephan; Bento, Manuela; Lew, Daniel; Etienne, Jérôme; Pittet, Didier; Schrenzel, Jacques

    2006-05-01

    The accessory gene regulator (agr) is a crucial regulatory component of Staphylococcus aureus involved in the control of bacterial virulence factor expression. We developed a real-time multiplex quantitative PCR assay for the rapid determination of S. aureus agr type. This assay represents a rapid and affordable alternative to sequence-based strategies for assessing relevant epidemiological information. PMID:16672433

  9. Rapid Staphylococcus aureus agr Type Determination by a Novel Multiplex Real-Time Quantitative PCR Assay

    Science.gov (United States)

    Francois, Patrice; Koessler, Thibaud; Huyghe, Antoine; Harbarth, Stephan; Bento, Manuela; Lew, Daniel; Etienne, Jérôme; Pittet, Didier; Schrenzel, Jacques

    2006-01-01

    The accessory gene regulator (agr) is a crucial regulatory component of Staphylococcus aureus involved in the control of bacterial virulence factor expression. We developed a real-time multiplex quantitative PCR assay for the rapid determination of S. aureus agr type. This assay represents a rapid and affordable alternative to sequence-based strategies for assessing relevant epidemiological information. PMID:16672433

  10. de cultivos agrícolas, en la agricultura urbana

    Directory of Open Access Journals (Sweden)

    Marcial A. Méndez F.

    2006-01-01

    Full Text Available El uso de las aguas residuales se presenta como una de las fuentes alternativas para el riego en la agricultura urbana. Esto entraña un conjunto de interrogantes en cuanto a su manejo y las posibles afectaciones que ellas puedan ocasionar a los frutos cosechados, al suelo y al medio ambiente. Las informaciones que se presentan, son solo los primeros resultados de los estudios introductorios hasta ahora realizados. Las aguas residuales del afluente Luyanó en el municipio Arroyo Naranjo, de acuerdo con los análisis realizados, se clasifican como aguas de baja contaminación (según los valores DBO5 y DQO obtenidos. Estas aguas, además, toxicológicamente no constituyen un riesgo de contaminación ni para el suelo ni para el medio ambiente, aunque no deben utilizarse sin tratamiento previo en cultivos de consumo directo, dada la carga microbiana que presentan. Las parcelas experimentales que se establecieron con cultivos de zanahoria, rábano y flor del Marigold, mostraron en las primeras cosechas que es posible alcanzar en ellas altos rendimientos agrícolas, dado el valor fertilizante de estas aguas residuales. Los resultados de la cosecha del rábano, según análisis bacteriológicos realizados, no mostraron ningún tipo de contaminación. El suelo y el entorno agrícola, tampoco presentaron afectaciones.

  11. A magyar agrárgazdaság napjainkban

    OpenAIRE

    Kapronczai, Istvan

    2011-01-01

    Ã chim L. András parasztpolitikus a nagybirtok elleni harc jelentős vezetője a XIX–XX. század fordulóján. A cikk a halálának centenáriuma alkalmából tartott emlékkonferencián elhangzott előadás alapján készült azzal az igénnyel, hogy bemutassa napjaink magyar agrárgazdaságát, és megkíséreljen párhuzamot vonni a 100 évvel ezelőtti kor, illetve a mai agrárgazdasággal szemben álló kihívások között. A 100 évvel ezelőtti viszonyok és a maiak között meglepő párhuzamok rajzolódtak ki: földosztás, a ...

  12. Mk A2 AGR irradiated fuel transport flask - A new UK flask design

    International Nuclear Information System (INIS)

    The transport of irradiated fuel from the UKs Advanced Gas Cooled Reactors to the reprocessing plant at Sellafield has, up to now, been undertaken using a composite lead in steel cuboid flask fitted with a detachable aluminum shock absorber. The commissioning of further AGR power stations necessitated the procurement of additional transport flasks and the opportunity was taken, by the CEGB, in line with their policy of continuous review to reassess the existing design against the need to produce a flask which would be acceptable for continued operation for the next 25-30 years. The design philosophy adopted was to meet the 1985 IAEA Regulations with the inclusion of cost effective margins as an insurance against possible changes in the Regulations which might occur during the lifetime of the design. Additionally, the response of the flask to possible real accident scenarios applicable to the method of transport used in the UK, provided an input to the design concept as did the need to adopt the ALARP concept applicable to radiation dose rates experienced during on site handling

  13. Neutronic of heterogenous gas cooled reactors

    International Nuclear Information System (INIS)

    At present, one of the main technical features of the advanced gas cooled reactor under development is its fuel element concept, which implies a neutronic homogeneous design, thus requiring higher enrichment compared with present commercial nuclear power plants.In this work a neutronic heterogeneous gas cooled reactor design is analyzed by studying the neutronic design of the Advanced Gas cooled Reactor (AGR), a low enrichment, gas cooled and graphite moderated nuclear power plant.A search of merit figures (some neutronic parameter, characteristic dimension, or a mixture of both) which are important and have been optimized during the reactor design stage is been done, to aim to comprise how a gas heterogeneous reactor is been design, given that semi-infinity arrangement criteria of rods in LWRs and clusters in HWRs can t be applied for a solid moderator and a gas refrigerator.The WIMS code for neutronic cell calculations is been utilized to model the AGR fuel cell and to calculate neutronic parameters such as the multiplication factor and the pick factor, as function of the fuel burnup.Also calculation is been done for various nucleus characteristic dimensions values (fuel pin radius, fuel channel pitch) and neutronic parameters (such as fuel enrichment), around the design established parameters values.A fuel cycle cost analysis is carried out according to the reactor in study, and the enrichment effect over it is been studied.Finally, a thermal stability analysis is been done, in subcritical condition and at power level, to study this reactor characteristic reactivity coefficients.Present results shows (considering the approximation used) a first set of neutronic design figures of merit consistent with the AGR design.

  14. Nacionalismos e reforma agrária nos anos 50

    Directory of Open Access Journals (Sweden)

    Moreira Vânia Maria Losada

    1998-01-01

    Full Text Available O artigo visa recuperar os elementos fundamentais do ideário nacionalista durante a década de 1950, destacando a centralidade do conceito de desenvolvimento auto-sustentado. A diversidade política e ideológica do movimento nacionalista é problematizada através da análise de duas correntes preponderantes do período em foco: o nacional-desenvolvimentismo, de caráter liberal, e o nacionalismo econômico, isto é, a vertente defendida pelas esquerdas. Finalmente, é focalizado a importância da reforma agrária dentro do projeto social defendido sobretudo pelos nacionalistas econômicos, enquanto fator indispensável a uma industrialização com cidadania.

  15. AGR-3/4 Irradiation Test Train Disassembly and Component Metrology First Look Report

    Energy Technology Data Exchange (ETDEWEB)

    Stempien, John Dennis [Idaho National Lab. (INL), Idaho Falls, ID (United States); Rice, Francine Joyce [Idaho National Lab. (INL), Idaho Falls, ID (United States); Harp, Jason Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Winston, Philip Lon [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-03-01

    The AGR-3/4 experiment was designed to study fission product transport within graphitic matrix material and nuclear-grade graphite. To this end, this experiment consisted of 12 capsules, each fueled with 4 compacts containing UCO TRISO particles as driver fuel and 20 UCO designed-to-fail (DTF) fuel particles in each compact. The DTF fuel was fabricated with a thin pyrocarbon layer which was intended to fail during irradiation and provide a source of fission products. These fission products could then migrate through the compact and into the surrounding concentric rings of graphitic matrix material and/or nuclear graphite. Through post-irradiation examination (PIE) of the rings (including physical sampling and gamma scanning) fission product concentration profiles within the rings can be determined. These data can be used to elucidate fission product transport parameters (e.g. diffusion coefficients within the test materials) which will be used to inform and refine models of fission product transport. After irradiation in the Advanced Test Reactor (ATR) had been completed in April 2014, the AGR-3/4 experiment was shipped to the Hot Fuel Examination Facility (HFEF) at the Materials and Fuels Complex (MFC) for inspection, disassembly, and metrology. The AGR-3/4 test train was received at MFC in two separate shipments between February and April 2015. Visual examinations of the test train exterior did not indicate dimensional distortion, and only two small discolored areas were observed at the bottom of Capsules 8 and 9. No corresponding discoloration was found on the inside of these capsules, however. Prior to disassembly, the two test train sections were subject to analysis via the Precision Gamma Scanner (PGS), which did not indicate that any gross fuel relocation had occurred. A series of specialized tools (including clamps, cutters, and drills) had been designed and fabricated in order to carry out test train disassembly and recovery of capsule components (graphite

  16. 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.

  17. Comparison of fission product release predictions using PARFUME with results from the AGR-1 irradiation experiment

    Energy Technology Data Exchange (ETDEWEB)

    Blaise Collin

    2014-09-01

    This report documents comparisons between post-irradiation examination measurements and model predictions of silver (Ag), cesium (Cs), and strontium (Sr) release from selected tristructural isotropic (TRISO) fuel particles and compacts during the first irradiation test of the Advanced Gas Reactor program that occurred from December 2006 to November 2009 in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL). The modeling was performed using the particle fuel model computer code PARFUME (PARticle FUel ModEl) developed at INL. PARFUME is an advanced gas-cooled reactor fuel performance modeling and analysis code (Miller 2009). It has been developed as an integrated mechanistic code that evaluates the thermal, mechanical, and physico-chemical behavior of fuel particles during irradiation to determine the failure probability of a population of fuel particles given the particle-to-particle statistical variations in physical dimensions and material properties that arise from the fuel fabrication process, accounting for all viable mechanisms that can lead to particle failure. The code also determines the diffusion of fission products from the fuel through the particle coating layers, and through the fuel matrix to the coolant boundary. The subsequent release of fission products is calculated at the compact level (release of fission products from the compact) but it can be assessed at the particle level by adjusting the diffusivity in the fuel matrix to very high values. Furthermore, the diffusivity of each layer can be individually set to a high value (typically 10-6 m2/s) to simulate a failed layer with no capability of fission product retention. In this study, the comparison to PIE focused on fission product release and because of the lack of failure in the irradiation, the probability of particle failure was not calculated. During the AGR-1 irradiation campaign, the fuel kernel produced and released fission products, which migrated through the successive

  18. AGR-2 Irradiated Test Train Preliminary Inspection and Disassembly First Look

    Energy Technology Data Exchange (ETDEWEB)

    Ploger, Scott [Idaho National Lab. (INL), Idaho Falls, ID (United States); Demkowciz, Paul [Idaho National Lab. (INL), Idaho Falls, ID (United States); Harp, Jason [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-05-01

    The AGR 2 irradiation experiment began in June 2010 and was completed in October 2013. The test train was shipped to the Materials and Fuels Complex in July 2014 for post-irradiation examination (PIE). The first PIE activities included nondestructive examination of the test train, followed by disassembly of the test train and individual capsules and detailed inspection of the capsule contents, including the fuel compacts and their graphite fuel holders. Dimensional metrology was then performed on the compacts, graphite holders, and steel capsule shells. AGR 2 disassembly and metrology were performed with the same equipment used successfully on AGR 1 test train components. Gamma spectrometry of the intact test train gave a preliminary look at the condition of the interior components. No evidence of damage to compacts or graphite components was evident from the isotopic and gross gamma scans. Disassembly of the AGR 2 test train and its capsules was conducted rapidly and efficiently by employing techniques refined during the AGR 1 disassembly campaign. Only one major difficulty was encountered while separating the test train into capsules when thermocouples (of larger diameter than used in AGR 1) and gas lines jammed inside the through tubes of the upper capsules, which required new tooling for extraction. Disassembly of individual capsules was straightforward with only a few minor complications. On the whole, AGR 2 capsule structural components appeared less embrittled than their AGR 1 counterparts. Compacts from AGR 2 Capsules 2, 3, 5, and 6 were in very good condition upon removal. Only relatively minor damage or markings were visible using high resolution photographic inspection. Compact dimensional measurements indicated radial shrinkage between 0.8 to 1.7%, with the greatest shrinkage observed on Capsule 2 compacts that were irradiated at higher temperature. Length shrinkage ranged from 0.1 to 0.9%, with by far the lowest axial shrinkage on Capsule 3 compacts

  19. Comparison of silver, cesium, and strontium release predictions using PARFUME with results from the AGR-1 irradiation experiment

    Science.gov (United States)

    Collin, Blaise P.; Petti, David A.; Demkowicz, Paul A.; Maki, John T.

    2015-11-01

    The PARFUME (PARticle FUel ModEl) code was used to predict the release of fission products silver, cesium, and strontium from tristructural isotropic coated fuel particles and compacts during the first irradiation experiment (AGR-1) of the Advanced Gas Reactor Fuel Development and Qualification program. The PARFUME model for the AGR-1 experiment used the fuel compact volume average temperature for each of the 620 days of irradiation to calculate the release of silver, cesium, and strontium from a representative particle for a select number of AGR-1 compacts. Post-irradiation examination (PIE) measurements provided data on release of these fission products from fuel compacts and fuel particles, and retention of silver in the compacts outside of the silicon carbide (SiC) layer. PARFUME-predicted fractional release of silver, cesium, and strontium was determined and compared to the PIE measurements. For silver, comparisons show a trend of over-prediction at low burnup and under-prediction at high burnup. PARFUME has limitations in the modeling of the temporal and spatial distributions of the temperature and burnup across the compacts, which affects the accuracy of its predictions. Nevertheless, the comparisons on silver release lie in the same order of magnitude. Results show an overall over-prediction of the fractional release of cesium by PARFUME. For particles with failed SiC layers, the over-prediction is by a factor of up to 3, corresponding to a potential over-estimation of the diffusivity in uranium oxycarbide (UCO) by a factor of up to 250. For intact particles, whose release is much lower, the over-prediction is by a factor of up to 100, which could be attributed to an over-estimated diffusivity in SiC by about 40% on average. The release of strontium from intact particles is also over-predicted by PARFUME, which also points towards an over-estimated diffusivity of strontium in either SiC or UCO, or possibly both. The measured strontium fractional release

  20. Survival of Listeria monocytogenes in Soil Requires AgrA-Mediated Regulation.

    Science.gov (United States)

    Vivant, Anne-Laure; Garmyn, Dominique; Gal, Laurent; Hartmann, Alain; Piveteau, Pascal

    2015-08-01

    In a recent paper, we demonstrated that inactivation of the Agr system affects the patterns of survival of Listeria monocytogenes (A.-L. Vivant, D. Garmyn, L. Gal, and P. Piveteau, Front Cell Infect Microbiol 4:160, http://dx.doi.org/10.3389/fcimb.2014.00160). In this study, we investigated whether the Agr-mediated response is triggered during adaptation in soil, and we compared survival patterns in a set of 10 soils. The fate of the parental strain L. monocytogenes L9 (a rifampin-resistant mutant of L. monocytogenes EGD-e) and that of a ΔagrA deletion mutant were compared in a collection of 10 soil microcosms. The ΔagrA mutant displayed significantly reduced survival in these biotic soil microcosms, and differential transcriptome analyses showed large alterations of the transcriptome when AgrA was not functional, while the variations in the transcriptomes between the wild type and the ΔagrA deletion mutant were modest under abiotic conditions. Indeed, in biotic soil environments, 578 protein-coding genes and an extensive repertoire of noncoding RNAs (ncRNAs) were differentially transcribed. The transcription of genes coding for proteins involved in cell envelope and cellular processes, including the phosphotransferase system and ABC transporters, and proteins involved in resistance to antimicrobial peptides was affected. Under sterilized soil conditions, the differences were limited to 86 genes and 29 ncRNAs. These results suggest that the response regulator AgrA of the Agr communication system plays important roles during the saprophytic life of L. monocytogenes in soil. PMID:26002901

  1. Comparison of fission product release predictions using PARFUME with results from the AGR-1 safety tests

    Energy Technology Data Exchange (ETDEWEB)

    Blaise Collin

    2014-09-01

    Safety tests were conducted on fourteen fuel compacts from AGR-1, the first irradiation experiment of the Advanced Gas Reactor (AGR) Fuel Development and Qualification program, at temperatures ranging from 1600 to 1800°C to determine fission product release at temperatures that bound reactor accident conditions. The PARFUME (PARticle FUel ModEl) code was used to predict the release of fission products silver, cesium, strontium, and krypton from fuel compacts containing tristructural isotropic (TRISO) coated particles during the safety tests, and the predicted values were compared with experimental results. Preliminary comparisons between PARFUME predictions and post-irradiation examination (PIE) results of the safety tests show different trends in the prediction of the fractional release depending on the species, and it leads to different conclusions regarding the diffusivities used in the modeling of fission product transport in TRISO-coated particles: • For silver, the diffusivity in silicon carbide (SiC) might be over-estimated by a factor of at least 102 to 103 at 1600°C and 1700°C, and at least 10 to 102 at 1800°C. The diffusivity of silver in uranium oxy-carbide (UCO) might also be over-estimated, but the available data are insufficient to allow definitive conclusions to be drawn. • For cesium, the diffusivity in UCO might be over-estimated by a factor of at least 102 to 103 at 1600°C, 105 at 1700°C, and 103 at 1800°C. The diffusivity of cesium in SiC might also over-estimated, by a factor of 10 at 1600°C and 103 at 1700°C, based upon the comparisons between calculated and measured release fractions from intact particles. There is no available estimate at 1800°C since all the compacts heated up at 1800°C contain particles with failed SiC layers whose release dominates the release from intact particles. • For strontium, the diffusivity in SiC might be over-estimated by a factor of 10 to 102 at 1600 and 1700°C, and 102 to 103 at 1800°C. These

  2. Ingeniería Agrícola

    Directory of Open Access Journals (Sweden)

    Pedro Valdés Hernández

    2007-01-01

    Full Text Available Este trabajo consiste en realizar los fundamentos metodológicos para la estructuración del programa de la disciplina Ciencias de la Ingeniería para el nuevo “Plan de Estudio D” de la Carrera Ingeniería Agrícola, que se caracteriza por un enfoque sistémico de los contenidos, un diseño del sistema de habilidades de las asignaturas que la conforman de forma general, se incorpora la semipresencialidad durante la impartición de las asignaturas en no más del 20 % del total de horas, se introducen las acciones a realizar de forma explícita para la formación de los valores trascendentales de la carrera, se establecen las acciones concretas por cada estrategia curricular, sobresaliendo el nivel informático que se exige por cada asignatura y el idioma Inglés. Por lo que existen doce aspectos que se recomiendan mejorar o incorporar como novedosos en el programa.

  3. Obreros agrícolas migrantes en Sinaloa

    Directory of Open Access Journals (Sweden)

    Florencio Posadas Segura

    2015-01-01

    Full Text Available el objetivo de este artículo es demostrar la presencia sig-nificativa de los obreros agrícolas migrantes, algunas carac-terísticas que la explican y la pauperización que experimen-tan. La causa principal de la migración es la desocupación;los empresarios controlan los métodos de contratación, tras-portación y explotación, y los jornaleros rurales migrantestrabajan más, ganan menos y su situación es mayormentemiserable. Esto se ilustra con el caso de Villa Benito Juárez,Sinaloa, que prueba la gran importancia de los asalariadosestacionales del campo, como auténticos productores de lariqueza, y la paradoja de su condición de pobreza aguda. Elpatrón migratorio interno y externo descubierto contradicelos estereotipos prevalecientes, en el marco de la reestruc-turación productiva y laboral de la agricultura mexicana yla incorporación de fuerza de trabajo asalariada pagada pordebajo de su valor, segmentada y dosificada conveniente-mente de acuerdo con la estrategia del capital, guiada por elespíritu de la ganancia máxima.

  4. Modelling of caesium deposition in CAGR reactor circuits

    International Nuclear Information System (INIS)

    A laboratory rig at BNL has been used to measure the deposition of radiocaesium in a CO2 gas stream onto steel surfaces in a thermal gradient furnace. The results of these measurements show that at high temperatures the deposition can be described by a model in which caesium diffuses into and out of the oxide film on the steel surface, with an evaporation boundary condition at the gas-oxide interface. A simple version of the model gives the deposition rate (dN)/dt = ngAot1/2 where ng is the concentration of caesium in the gas and Ao, the 'absorptivity', is a property of the surface. At low temperatures (below about 300 deg. C), caesium was retained by the surface. More recently, the experimental programme has been extended to cover deposition on graphite surfaces. Results show that significant retention takes place at temperatures typical of the cooler region of a CAGR circuit, although desorption is rapid at higher temperatures. A computer programme, CAESAR3, has been written to apply this model to the circuit of a CAGR. The programme handles a flexible set of parameters and can accommodate changing temperatures, pressures, flow rates, leak rates and source terms in a circuit which may have two interconnected branches. Measurements have been made of caesium distributions in the boilers of the Windscale prototype AGR and in the Hinkley Point 'B' CAGR. The results obtained are broadly in agreement with the model, although there are a number of apparent differences. Possible reasons for these are discussed. (author)

  5. Methods for studying fuel management in advanced gas cooled reactors

    International Nuclear Information System (INIS)

    The methods used for studying fuel and absorber management problems in AGRs are described. The basis of the method is the use of ARGOSY lattice data in reactor calculations performed at successive time steps. These reactor calculations may be quite crude but for advanced design calculations a detailed channel-by-channel representation of the whole core is required. The main emphasis of the paper is in describing such an advanced approach - the ODYSSEUS-6 code. This code evaluates reactor power distributions as a function of time and uses the information to select refuelling moves and determine controller positions. (author)

  6. A Survey of the Fuel Cycles Operated in the United Kingdom

    International Nuclear Information System (INIS)

    (a) The natural uranium/ magnox fuel cycle. The United Kingdom have chosen the natural uranium graphite-moderated gas-cooled reactor as the basis of their nuclear power programme. They have operated the reactors at Calder Hall and Chapelcross for seven years; the Berkeley and Bradwell reactors of the CEGB are now operating, and reactors at seven other sites are under construction or planned. The fuel for these reactors is designed and manufactured at the U.K.A.E.A. Springfields factory and then transported to the reactor site for loading. After irradiation and discharge the fuel is transported to the U.K.A.E.A. site at Windscale for separation of uranium and plutonium from fission products. The paper outlines the UK experience of design and manufacture of fuel, re actor operation, transport of irradiated fuel and subsequent processing of the fuel. Mention is made of the behaviour of fuel in a reactor and alternative charging and discharging programmes, the subject is further elaborated in another paper. (b) Reactors using enriched fuels. The UK are developing an advanced gas-cooled reactor (AGR), the prototype reactor of which came on power in 1963. The fuel is manufactured from enriched uranium oxide canned in stainless steel and it will be reprocessed through a ''head-end'' which will be added to the Windscale Magnox separation plant. The enriched uranium for the AGR is produced in the UK Diffusion Plant at Capenhurst. An alternative to enriched uranium oxide as a fuel is plutonium-enriched natural-uranium oxide. The paper outlines the experience in production of oxide fuel for AGR, the operating experience with the reactor so far and the plans for reprocessing the fuel. The alternative use of a plutonium fuel is considered and the effects of this on costs and the fuel cycle. Finally the paper outlines the place of Magnox and AGR reactors in the UK power programme. (author)

  7. Qual o custo governamental do seguro agrícola?

    Directory of Open Access Journals (Sweden)

    Vitor Augusto Ozaki

    2013-03-01

    Full Text Available Para 2011, estavam previstos R$ 570 milhões ao Programa de Subvenção ao Prêmio do Seguro Rural (PSR, mas apenas R$ 253,4 milhões foram alocados ao Programa em função de contingenciamentos do governo. Apesar disso, foi possível segurar 5,6 milhões de hectares com uma importância segurada de R$ 7,3 bilhões. Mas qual deveria ser o volume de recursos direcionados ao PSR para que todo o crédito de custeio das lavouras pudesse ser coberto pelo mercado segurador? O estudo apresenta uma metodologia para calcular qual deve ser o valor orçamentário médio do PSR para cobrir cem por cento do custeio das lavouras. Para 2011, os resultados sugerem que o volume de recursos deveria ter sido quatro vezes maior do que o valor empenhado. Ademais, os resultados foram desagregados por estado e por culturas agrícolas. A importância do PSR para a massificação do seguro rural é indiscutível. Porém, além dos recursos do PSR estarem subdimensionados, outro problema ameaça a continuidade do Programa. Pelo terceiro ano consecutivo, o PSR tem sofrido graves contingenciamentos que têm impactado negativamente o mercado. Portanto, fica evidente a necessidade de maior esforço do governo federal em ampliar os recursos da subvenção e destiná-los única e integralmente ao PSR.

  8. Radionuclide compositions of spent fuel and high level waste from commercial nuclear reactors

    International Nuclear Information System (INIS)

    This report provides information on radionuclide compositions of spent fuel and high level waste produced during reprocessing. The reactor types considered are Magnox, AGR, PWR and CFR. The activities of the radionuclides are calculated using the FISPIN code. The results are presented in a form suitable for radioactive waste management calculations. (author)

  9. Saúde e mercado de trabalho no Brasil: diferenciais entre ocupados agrícolas e não agrícolas

    Directory of Open Access Journals (Sweden)

    Alexandre Gori Maia

    2010-12-01

    Full Text Available Este trabalho analisa as diferenças no estado de saúde entre e dentro dos grupos de ocupados agrícolas e não agrícolas no Brasil, utilizando medidas de autoavaliação do estado de saúde captadas no suplemento da PNAD (Pesquisa Nacional por Amostra de Domicílios de 2008. As análises baseiam-se na composição socioeconômica dos ocupados agrícolas e não agrícolas e nas estimativas de equações simultâneas para captar as relações não lineares entre saúde, renda e jornada de trabalho. Um dos pressupostos do trabalho é que a baixa prevalência de saudáveis entre os ocupados agrícolas estaria associada, sobretudo, à composição socioeconômica desse grupo, e não à maior insalubridade a que os ocupados das atividades agrícolas estariam submetidos em condições socioeconômicas semelhantes às dos não agrícolas. Analogamente, a desigualdade no estado de saúde seria menor entre os ocupados agrícolas devido aos hábitos mais homogêneos, não só no que se refere ao tipo de atividade, mas também em relação à qualidade de vida e ao acesso a uma série de itens de consumo, típico das localidades menos desenvolvidas onde as atividades agrícolas prevalecem.This paper analyzes differences of health conditions between and within agricultural and non-agricultural workers in Brazil. Self-reported health measures of the Health Supplement of Pesquisa Nacional por Amostra de Domicílios (PNAD, from 2008, are used. Results are based on the description of the socioeconomic characteristics of each group of employees and on estimates of a simultaneous equation to measure non-linear relations between health conditions, income and work hours. The main hypothesis is that the lower prevalence of workers with good health among agricultural workers is mainly due to socioeconomic characteristics of this group and not necessarily to higher insalubrious conditions that such workers would be submitted to in equivalent socioeconomic conditions

  10. Modelling the effects of flexible operation on AGR fuel integrity

    International Nuclear Information System (INIS)

    The Commercial Advanced Gas Cooled Reactor (CAGR) is fuelled with so-called pins' consisting of a stainless steel cladding containing enriched uranium dioxide pellets. Post Irradiation Examination (PIE) of CAGR pins has revealed the common phenomenon of bonding of the clad material to a thin sliver of the UO2 fuel material. This phenomenon is associated with the development of small cracks in the inner surface of the clad. The NIMROD model has been developed to allow the study of clad behaviour in new CAGR operational regimes when the core contains fuel exhibiting these characteristics. This model is described and is a code module within the fuel performance code ENIGMA. ENIGMA calculates the thermal mechanical response of a fuel pin to a specified rating history. The NIMROD module uses the boundary conditions supplied by ENIGMA to calculate the effect of the power history on the bonded clad and the consequent crack growth and wall thinning. The successful validation of this model has been based on data available from CAGR PIE and a transient test series performed at the OECD Halden test reactor. The validations have used measured in-reactor power histories with the observed crack damage and wall thinning from the subsequent PIE. A discussion of the predictions and implications of the model for CAGR performance in some possible reactor scenarios is presented. (UK)

  11. ¿Qué determina la productividad agrícola departamental en Colombia?

    OpenAIRE

    Luis Armando Galvis Aponte

    2001-01-01

    Las condiciones geográficas de un país o región inciden sobre su desempeño económico a través de la productividad agrícola y la salud de la población. En este trabajo se analiza una de esas vías, la de la productividad agrícola, a partir de un modelo econométrico de corte transversal aplicado a los departamentos de Colombia. Se estimó la relación entre el PIB agrícola per cápita y algunas variables geográficas, y se concluyó que en 1997 más del 80% de la variabilidad de los niveles de product...

  12. Saberes agrícolas tradicionales como programa académico

    Directory of Open Access Journals (Sweden)

    J. Antonio Gómez Espinoza

    2008-01-01

    Full Text Available En el marco de las crisis social y ambiental del tercer milenio, se hace necesario repensar la universidad, sus paradigmas, el concepto de educación y su modelo educativo para impactar en la construcción de la nueva sociedad. Los Saberes Agrícolas Tradicionales (SAT aportan elementos conceptuales básicos para la implementación y desarrollo de una sociedad sustentable. A partir del rescate, la sistematización de los SAT y el diálogo intercultural SAT-ciencia, se propone incorporar los Saberes Agrícolas Tradicionales como programa académico en las Instituciones de Enseñanza y Aprendizaje Agrícola del nivel Superior (IEAS.

  13. Biotecnología agrícola

    Directory of Open Access Journals (Sweden)

    Melgarejo, Paloma

    2014-08-01

    Full Text Available The domestication of plants can be considered as the first genetic manipulation of living organisms and it is associated with the origin of agriculture, and represents the major contribution of biotechnology to the development of mankind. The challenges the agricultural sector faces in the coming decades are population growth and the increasing demand for raw materials for food, feed, as well as the consumer preferences, environmental and legal aspects, and the overall globalisation of the economy. The agricultural biotechnology applications will undoubtedly play a role in meeting these challenges. Spain has competent scientific groups devoted to basic and applied research, with a wide knowledge on agricultural biotechnology. The transfer of the business sector needs to the scientific field, coordinating the R&D companies and research groups from universities and public research organisms is an objective to be attained in the future.La domesticación de plantas, primera manipulación genética de los organismos vivos y origen de la Agricultura, representa la mayor contribución de la biotecnología al desarrollo de la humanidad. Los retos a superar en las próximas décadas para el sector agrario están determinados por el aumento demográfico y la demanda de materias primas para alimentación humana y animal, por las preferencias en el consumo, por aspectos medioambientales y legales, y por la globalización de la economía. Las aplicaciones de la biotecnología agrícola van a jugar un papel incuestionable en el logro de estos retos. Nuestro país posee unos buenos grupos en investigación básica y aplicada, con amplios conocimientos de la agrobiotecnología. El traslado de las necesidades del sector empresarial a la investigación, coordinando los departamentos de I+D+I de las empresas y los grupos de investigación de las universidades y organismos públicos de investigación es una finalidad a conseguir en el futuro.

  14. Boom Agrícola y Persistencia de la Pobreza Rural en Argentina

    OpenAIRE

    Guardia, Laura; Tornarolli, Leopoldo

    2010-01-01

    El presente capítulo realiza un análisis de la evolución de la pobreza rural en Argentina desde 1991 a 2006, a partir de las diversas fuentes de información disponibles. Este período se caracteriza por importantes cambios en el sector agrícola, entre los que se destaca la explosiva expansión de la agricultura en gran parte del territorio nacional, liderada por el cultivo de la soja. Este “boom agrícola” ha sido el resultado de importantes cambios tecnológicos y organizativos que se traduce...

  15. Preparation for Future Defuelling and Decommissioning Works on EDF Energy's UK Fleet of Advanced Gas Cooled Reactors

    International Nuclear Information System (INIS)

    EDF Energy/Nuclear Generation is the owner and operator of 14 Advanced Gas cooled Reactors (AGR) and one Pressurised Water Reactor (PWR), on 8 nuclear stations in the UK. EDF Energy/Nuclear Generation is responsible for all the activities associated with the end of life of its nuclear installations: de-fuelling, decommissioning and waste management. As the first AGR is forecast to cease generation within 10 years, EDF Energy has started planning for the decommissioning. This paper covers: - broad outline of the technical strategy and arrangements for future de-fuelling and decommissioning works on the UK AGR fleet, - high level strategic drivers and alignment with wider UK nuclear policy, - overall programme of preparation and initial works, - technical approaches to be adopted during decommissioning. (authors)

  16. Fusões no Crédito Agrícola: o caso da Caixa Agrícola do Litoral Alentejano

    OpenAIRE

    Batista, Ana Carina Gomes

    2009-01-01

    Nos últimos anos, as Fusões e Aquisições têm constituído um dos meios privilegiados pela banca para assinalarem a sua posição competitiva. Diversos autores debruçam-se sobre a análise das motivações e consequências das Fusões e Aquisições, outros estudos visam encontrar evidência que favoreça a relação entre concentração e poder de mercado. O presente trabalho estuda o processo de fusão que ocorreu entre a Caixa Agrícola do Baixo Sado e Caixa Agrícola da Costa Alentejana, a qua...

  17. AGR-1 Irradiated Test Train Preliminary Inspection and Disassembly First Look

    Energy Technology Data Exchange (ETDEWEB)

    Paul Demkowicz; Lance Cole; Scott Ploger; Philip Winston; Binh Pham; Michael Abbott

    2011-01-01

    The AGR-1 irradiation experiment ended on November 6, 2009, after 620 effective full power days in the Advanced Test Reactor, achieving a peak burnup of 19.6% FIMA. The test train was shipped to the Materials and Fuels Complex in March 2010 for post-irradiation examination. The first PIE activities included non-destructive examination of the test train, followed by disassembly of the test train and individual capsules and detailed inspection of the capsule contents, including the fuel compacts and the graphite fuel holders. Dimensional measurements of the compacts, graphite holders, and steel capsules shells were performed using a custom vision measurement system (for outer diameters and lengths) and conventional bore gauges (for inner diameters). Gamma spectrometry of the intact test train gave a preliminary look at the condition of the interior components. No evidence of damage to compacts or graphite components was evident from the isotopic and gross gamma scans. Neutron radiography of the intact Capsule 2 showed a high degree of detail of interior components and confirmed the observation that there was no major damage to the capsule. Disassembly of the capsules was initiated using procedures qualified during out-of-cell mockup testing. Difficulties were encountered during capsule disassembly due to irradiation-induced changes in some of the capsule components’ properties, including embrittled niobium and molybdenum parts that were susceptible to fracture and swelling of the graphite fuel holders that affected their removal from the capsule shells. This required various improvised modifications to the disassembly procedure to avoid damage to the fuel compacts. Ultimately the capsule disassembly was successful and only one compact from Capsule 4 (out of 72 total in the test train) sustained damage during the disassembly process, along with the associated graphite holder. The compacts were generally in very good condition upon removal. Only relatively minor

  18. IFPE/CAGR-UOX-SWELL, Fuel swelling Data Obtained from the AGR/Halden Ramp Test Programme

    International Nuclear Information System (INIS)

    Description: An extensive study of fuel swelling in oxide fuel has been performed on fuel which has been ramp-tested in the Halden Heavy Boiling Water Reactor. The ramp-tests were performed to study the mechanisms of P CI in Advanced Gas-cooled Reactor fuel (AGR) but the initial clad deformation measurements were later supplemented by the use of Transmission Electron Microscopy (Tem) and Scanning Electron Microscopy (Sem). The driving force for P CI arises from a combination of pellet thermal expansion and the creation of fission gas porosity during a temperature/rating transient. Fuel specimens from thirteen ramped rods and two control-reference rods have been examined using Tem and Sem. Swelling measurements have been made at four or five radial locations in the fuel. At least six full grain boundaries were used for the inter-granular study at each location and three complete trans-granular fractures employed for the intra-granular bubbles. In the latter case, the trans-granular regions were examined under very high magnifications to reveal pores as small as 20-25 nm diameter. The Sem study comprises nearly three thousand micrographs. The microscope study was augmented by use of the Enigma fuel modelling code to obtain estimates of the local temperatures and conditions from which the Sem/Tem samples were obtained. Nea-1705/02: The analysis from the 4135, 4136 and 4140 data has been incorporated. Data 4000, 4004, 4064, 4065, 4162, and 4163 have been revised. Many of the tables have been improved. The main report has been extensively modified from the earlier version

  19. AGR fuel pin pellet-clad interaction failure limits and activity release fractions

    International Nuclear Information System (INIS)

    The limiting conditions beyond which pellet-clad interaction can flail AGR fuel are described. They have been determined by many experiments involving post-irradiation examination and testing, loop experiments and cycling and up-rating of both individual fuel stringers and the whole WAGR core. The mechanisms causing this interaction are well understood and are quantitatively expressed in computer codes. Strain concentration effects over fuel cracks determine power cycling endurance while additional strain concentrations at clad ridges and from cross pin temperature gradients contribute to up-rating failures. An equation summarising tube burst test data so as to determine the ductility available at any transient is given. The hollow fuel and more ductile clad of the Civil AGR fuel pins leads to a much improved performance over the original fuel design. The Civil AGRs operate well within these limiting conditions and substantial increases beyond the design burn-up are confidently expected. The activity release on pin failure and its development during continued operation of failed fuel have also been investigated. A retention of radioiodine and caesium of 90-99% compared to the noble gases has been demonstrated. Measured fission gas releases into the free volume of Civil AGR fuel pins have been very low (< 0.1%)

  20. INITIAL IRRADIATION OF THE FIRST ADVANCED GAS REACTOR FUEL DEVELOPMENT AND QUALIFICATION EXPERIMENT IN THE ADVANCED TEST REACTOR

    Energy Technology Data Exchange (ETDEWEB)

    S. Blaine Grover; David A. Petti

    2007-09-01

    The United States Department of Energy’s Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating eight separate tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States. The ATR has a long history of irradiation testing in support of reactor development and the INL has been designated as the United States Department of Energy’s lead laboratory for nuclear energy development. The ATR is one of the world’s premiere test reactors for performing long term, high flux, and/or large volume irradiation test programs. These AGR fuel experiments will be irradiated over the next ten years to demonstrate and qualify new particle fuel for use in high temperature gas reactors. The experiments, which will each consist of six separate capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control for each capsule. The swept gas will also have on-line fission product monitoring to track performance of the fuel in each individual capsule during irradiation.

  1. Supercritical CO2 direct cycle Gas Fast Reactor (SC-GFR) concept.

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Steven Alan; Parma, Edward J., Jr.; Suo-Anttila, Ahti Jorma (Computational Engineering Analysis, Albuquerque, NM); Al Rashdan, Ahmad (Texas A& M University, College Station, TX); Tsvetkov, Pavel Valeryevich (Texas A& M University, College Station, TX); Vernon, Milton E.; Fleming, Darryn D.; Rochau, Gary Eugene

    2011-05-01

    This report describes the supercritical carbon dioxide (S-CO{sub 2}) direct cycle gas fast reactor (SC-GFR) concept. The SC-GFR reactor concept was developed to determine the feasibility of a right size reactor (RSR) type concept using S-CO{sub 2} as the working fluid in a direct cycle fast reactor. Scoping analyses were performed for a 200 to 400 MWth reactor and an S-CO{sub 2} Brayton cycle. Although a significant amount of work is still required, this type of reactor concept maintains some potentially significant advantages over ideal gas-cooled systems and liquid metal-cooled systems. The analyses presented in this report show that a relatively small long-life reactor core could be developed that maintains decay heat removal by natural circulation. The concept is based largely on the Advanced Gas Reactor (AGR) commercial power plants operated in the United Kingdom and other GFR concepts.

  2. Axisymmetric whole pin life modelling of advanced gas-cooled reactor nuclear fuel

    International Nuclear Information System (INIS)

    Thermo-mechanical contributions to pellet–clad interaction (PCI) in advanced gas-cooled reactors (AGRs) are modelled in the ABAQUS finite element (FE) code. User supplied sub-routines permit the modelling of the non-linear behaviour of AGR fuel through life. Through utilisation of ABAQUS’s well-developed pre- and post-processing ability, the behaviour of the axially constrained steel clad fuel was modelled. The 2D axisymmetric model includes thermo-mechanical behaviour of the fuel with time and condition dependent material properties. Pellet cladding gap dynamics and thermal behaviour are also modelled. The model treats heat up as a fully coupled temperature-displacement study. Dwell time and direct power cycling was applied to model the impact of online refuelling, a key feature of the AGR. The model includes the visco-plastic behaviour of the fuel under the stress and irradiation conditions within an AGR core and a non-linear heat transfer model. A multiscale fission gas release model is applied to compute pin pressure; this model is coupled to the PCI gap model through an explicit fission gas inventory code. Whole pin, whole life, models are able to show the impact of the fuel on all segments of cladding including weld end caps and cladding pellet locking mechanisms (unique to AGR fuel). The development of this model in a commercial FE package shows that the development of a potentially verified and future-proof fuel performance code can be created and used

  3. AGR3 in Breast Cancer: Prognostic Impact and Suitable Serum-Based Biomarker for Early Cancer Detection

    Science.gov (United States)

    Garczyk, Stefan; von Stillfried, Saskia; Antonopoulos, Wiebke; Hartmann, Arndt; Schrauder, Michael G.; Fasching, Peter A.; Anzeneder, Tobias; Tannapfel, Andrea; Ergönenc, Yavuz; Knüchel, Ruth

    2015-01-01

    Blood-based early detection of breast cancer has recently gained novel momentum, as liquid biopsy diagnostics is a fast emerging field. In this study, we aimed to identify secreted proteins which are up-regulated both in tumour tissue and serum samples of breast cancer patients compared to normal tissue and sera. Based on two independent tissue cohorts (n = 75 and n = 229) and one serum cohort (n = 80) of human breast cancer and healthy serum samples, we characterised AGR3 as a novel potential biomarker both for breast cancer prognosis and early breast cancer detection from blood. AGR3 expression in breast tumours is significantly associated with oestrogen receptor α (P<0.001) and lower tumour grade (P<0.01). Interestingly, AGR3 protein expression correlates with unfavourable outcome in low (G1) and intermediate (G2) grade breast tumours (multivariate hazard ratio: 2.186, 95% CI: 1.008-4.740, P<0.05) indicating an independent prognostic impact. In sera analysed by ELISA technique, AGR3 protein concentration was significantly (P<0.001) elevated in samples from breast cancer patients (n = 40, mainly low stage tumours) compared to healthy controls (n = 40). To develop a suitable biomarker panel for early breast cancer detection, we measured AGR2 protein in human serum samples in parallel. The combined AGR3/AGR2 biomarker panel achieved a sensitivity of 64.5% and a specificity of 89.5% as shown by receiver operating characteristic (ROC) curve statistics. Thus our data clearly show the potential usability of AGR3 and AGR2 as biomarkers for blood-based early detection of human breast cancer. PMID:25875093

  4. Safety design features for current UK advanced gas-cooled reactors

    International Nuclear Information System (INIS)

    The nuclear power stations planned for Heysham II and Torness will each have twin 660 MW(e) Advanced Gas-cooled Reactors (AGR) based on the design of those which have been operating at Hinkley Point 'B' and Hunterston 'B' since 1976. This paper has described the way in which the shutdown and cooling systems for the Heysham II and Torness AGRs have been selected in order to meet current UK safety requirements. Fault tree analyses have been used to identify the credible fault sequences, the probabilities of which have been calculated. By this means the relative importance of the various protective systems has been established and redundancy and reliability requirements identified. This systematic approach has led to a balanced design giving protection over the complete spectrum of fault sequences. Current safety requirements for thermal reactors in the UK and particular requirements in the design of the Heysham II and Torness reactors are discussed

  5. Aptitud relativa agrícola del municipio de Tuxpan, Nayarit, utilizando el modelo Almagra del Sistema MicroLEIS

    OpenAIRE

    José López García; Diego de la Rosa Acosta; José Irán Bojórquez Serrano

    2006-01-01

    Se realizó la evaluación de tierras para uso agrícola en la llanura fluviomarina dentro del municipio de Tuxpan, Nayarit, con base en un levantamiento de suelos semidetallado. Se evaluó la aptitud relativa agrícola, mediante la modificación del modelo Almagra del sistema MicroLEIS 4.1, el cual permite definir la aptitud relativa agrícola, de lo cual resulta el Almagra-Tuxpan, al crearse una base de datos con las condiciones específicas de esta región. Con base en el modelo Almagra...

  6. Disputa territorial, conceitualização e atualidade da Reforma Agrária no Brasil

    OpenAIRE

    Fernandes Rocha, Herivelto

    2013-01-01

    A questão Agrária, ou seja, os problemas agrários gerados pela expansão e reprodução ampliada do capitalismo no campo, no Brasil está intrinsecamente relacionada com a conflitualidade entre diferentes modelos de desenvolvimento que disputam o controle territorial do país. Na primeira parte deste trabalho apresentamos uma análise da conceitualização da Reforma Agrária, tomando como base os trabalho dos principais autores que trataram do tema, e os resultados da implementação desta política púb...

  7. A review of control rod calibration methods for irradiated AGRs

    International Nuclear Information System (INIS)

    Methods of calibrating control rods with particular reference to irradiated CAGR are surveyed. Some systematic spatial effects are found and an estimate of their magnitude made. It is concluded that control rod oscillation provides a promising method of calibrating rods at power which is as yet untried on CAGR. Also the rod drop using inverse kinetics provides a rod calibration but spatial effects may be large and these would be difficult to correct theoretically. The pulsed neutron technique provides a calibration route with small errors due to spatial effects provided a suitable K-tube can be developed. The xenon transient method is shown to have statial effects which have not needed consideration in earlier reactors but which in CAGR would need very careful evaluation. (author)

  8. A review of control rod calibration methods for irradiated AGRs

    International Nuclear Information System (INIS)

    Methods of calibrating control rods with particular reference to irradiated CAGR are surveyed. Some systematic spatial effects are found and an estimate of their magnitude made. It is concluded that control rod oscillation provides a promising method of calibrating rods at power which is as yet untried on CAGR. Also the rod drop using inverse kinetics provides a rod calibration but spatial effects may be large and these would be difficult to correct theoretically. The pulsed neutron technique provides a calibration route with small errors due to spatial effects provided a suitable K-tube can be developed. The xenon transient method is shown to have spatial effects which have not needed consideration in earlier reactors but which in CAGR would need very careful evaluation. (author)

  9. N Reactor

    Data.gov (United States)

    Federal Laboratory Consortium — The last of Hanfordqaodmasdkwaspemas7ajkqlsmdqpakldnzsdflss nine plutonium production reactors to be built was the N Reactor.This reactor was called a dual purpose...

  10. Irradiation of the First Advanced Gas Reactor Fuel Development and Qualification Experiment in the Advanced Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    S. Blaine Grover; David A. Petti

    2008-10-01

    The United States Department of Energy’s Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating eight separate tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States. The ATR has a long history of irradiation testing in support of reactor development and the INL has been designated as the United States Department of Energy’s lead laboratory for nuclear energy development. These AGR fuel experiments will be irradiated over the next ten years to demonstrate and qualify new particle fuel for use in high temperature gas reactors. The experiments, which will each consist of six separate capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control for each capsule. The swept gas will also have on-line fission product monitoring to track performance of the fuel in each individual capsule during irradiation. The design of the first experiment (designated AGR-1) was completed in 2005, and the fabrication and assembly of the test train as well as the support systems and fission product monitoring system that monitor and control the experiment during irradiation were completed in September 2006. The experiment was inserted in the ATR in December 2006, and is serving as a shakedown test of the multi-capsule experiment design that will be used in the subsequent irradiations as well as a test of the early variants of the fuel produced under this program. The experiment test train as well as the monitoring, control, and data collection systems are discussed and the status of the experiment is provided.

  11. Some aspects of the dynamics of AGR gas circulators

    International Nuclear Information System (INIS)

    The various types of vibration found on the gas circulators of an advanced gas-cooled reactor (Hinkley Point 'B' design) are categorized and described briefly. Those due to rotor unbalance or its lack of straightness are considered in detail where it is attempted to highlight certain aspects of the dynamic behaviour which are considered of particular importance to designers either because of the results themselves or the techniques used in obtaining them; for example, the practical utilization of the finite-element technique in the mathematical modelling process. One interesting aspect relates to the interaction between the circulator rotor modes of vibration and those of the over-hung impeller. Another deals with the condition of a permanent rotor bend near the impeller as the source of vibration excitation. Various states of rotor unbalance have also been simulated. The work led to general conclusions which were utilized in resolving specific questions related to the balancing of refurbished circulators; it also increased the understanding of their dynamic behaviour thus leading to more operational confidence. (author)

  12. La Ingeniería Agrícola en el País

    Directory of Open Access Journals (Sweden)

    Bustamante M. Hellodoro

    1985-12-01

    Full Text Available Es sumamente difícil situar en la historia, el origen de la Ingeniería Agrícola, aunque podría remontarse al propio origen de la tierra, de las plantas y de las aguas. La Ingeniería Agrícola está ocupando un campo de acción que se ha desarrollado a pesar de las limitaciones que le ofrece el mismo desarrollo del país y al escepticismo sin fundamento de algunos pregoneros del pesimismo nacional; le corresponde enfrentar además hoy al cáncer del desempleo y a la falta de oportunidad para demostrar al país que la inversión hecha por el estado en la formación de estos profesionales es productiva.

  13. Diseño de un sistema de riego agrícola controlado a distancia

    OpenAIRE

    Monge Álvarez, Jesús

    2015-01-01

    En este TFM se plantea el diseño de un prototipo que constituya una innovación incremental de una de las tecnologías de riego agrícola más recientes: los pívots de regadío. Los dos objetivos que se pretenden conseguir con este prototipo son: un uso más eficiente del agua empleada en el regadío agrícola y evitar largos desplazamientos para la simple puesta en marcha o monitorización del pívot. Su parte hardware está basada en la placa computadora Raspberry Pi junto con la placa Custard Pi 2...

  14. FABRICATION PROCESS AND PRODUCT QUALITY IMPROVEMENTS IN ADVANCED GAS REACTOR UCO KERNELS

    Energy Technology Data Exchange (ETDEWEB)

    Charles M Barnes

    2008-09-01

    A major element of the Advanced Gas Reactor (AGR) program is developing fuel fabrication processes to produce high quality uranium-containing kernels, TRISO-coated particles and fuel compacts needed for planned irradiation tests. The goals of the AGR program also include developing the fabrication technology to mass produce this fuel at low cost. Kernels for the first AGR test (“AGR-1) consisted of uranium oxycarbide (UCO) microspheres that werre produced by an internal gelation process followed by high temperature steps tot convert the UO3 + C “green” microspheres to first UO2 + C and then UO2 + UCx. The high temperature steps also densified the kernels. Babcock and Wilcox (B&W) fabricated UCO kernels for the AGR-1 irradiation experiment, which went into the Advance Test Reactor (ATR) at Idaho National Laboratory in December 2006. An evaluation of the kernel process following AGR-1 kernel production led to several recommendations to improve the fabrication process. These recommendations included testing alternative methods of dispersing carbon during broth preparation, evaluating the method of broth mixing, optimizing the broth chemistry, optimizing sintering conditions, and demonstrating fabrication of larger diameter UCO kernels needed for the second AGR irradiation test. Based on these recommendations and requirements, a test program was defined and performed. Certain portions of the test program were performed by Oak Ridge National Laboratory (ORNL), while tests at larger scale were performed by B&W. The tests at B&W have demonstrated improvements in both kernel properties and process operation. Changes in the form of carbon black used and the method of mixing the carbon prior to forming kernels led to improvements in the phase distribution in the sintered kernels, greater consistency in kernel properties, a reduction in forming run time, and simplifications to the forming process. Process parameter variation tests in both forming and sintering steps led

  15. Corrosion studies of thermally sensitised AGR fuel element brace in pH7 and pH9.2 borate solutions

    International Nuclear Information System (INIS)

    Brace and cladding of AGR fuel elements sensitised in reactor are susceptible to intergranular and crevice corrosion, which may initiate in the pH7 borate pond storage environment of CEGB/SSEB stations. This report considers the benefit in corrosion control that is provided by raising the pond solution pH to 9.2, whilst maintaining the boron level at 1250 gm-3. The greater corrosion protection provided by pH9.2 solution compared to the pH7 borate solution is demonstrated by a series of tests with non-active laboratory sensitised brace samples exposed to solutions dosed with chloride or sulphate in order to promote localised corrosion. The corrosion tests undertaken consisted of 5000 hour immersions at 320C and shorter term electrochemically monitored experiments (rest potential, impedance, anodic current) generally conducted at 220C. The pH9.2 solution effectively inhibited the initiation of crevice and intergranular corrosion in the presence of low levels of chloride and sulphate, whereas the pH7 solution did not always do so. However, the pH9.2 solution, dosed with 40 gm-3 chloride, failed to suppress fully crevice corrosion initiated in unborated 40 gm-3 chloride solution at 220C. Fluoride is not deleterious at low levels ∼ 10 gm-3 in the borate solutions. The significant improvement in corrosion control demonstrated for the change from pH7 to pH9.2 borate solution on laboratory sensitised brace samples should ideally be confirmed using complete irradiated AGR fuel elements. (U.K.)

  16. Design for reactor core safety in nuclear power plants

    International Nuclear Information System (INIS)

    This Guide covers the neutronic, thermal, hydraulic, mechanical, chemical and irradiation considerations important to the safe design of a nuclear reactor core. The Guide applies to the types of thermal neutron reactor power plants that are now in common use and fuelled with oxide fuels: advanced gas cooled reactor (AGR), boiling water reactor (BWR), pressurized heavy water reactor (PHWR) (pressure tube and pressure vessel type) and pressurized water reactor (PWR). It deals with the individual components and systems that make up the core and associated equipment and with design provisions for the safe operation of the core and safe handling of the fuel and other core components. The Guide discusses the reactor vessel internals and the reactivity control and shutdown devices mounted on the vessel. Possible effects on requirements for the reactor coolant, the reactor coolant system and its pressure boundary (including the pressure vessel) are considered only as far as necessary to clarify the interface with the Safety Guide on Reactor Coolant and Associated Systems in Nuclear Power Plants (IAEA Safety Series No. 50-SG-D13) and other Guides. In relation to instrumentation and control systems the guidance is mainly limited to functional requirements

  17. Desarrollo y perspectiva de la Ingeniería Agrícola

    Directory of Open Access Journals (Sweden)

    Julio E. Ospina Mejía

    2011-02-01

    Full Text Available La Ingeniería Agrícola es la rama de la ingeniería orientada a dar respuesta a los problemas que plantea la agricultura moderna, mediante la aplicación de principios de las ciencias naturales y las matemáticas, procurando la conservación y el aumento del potencial del suelo, la producción de alimentos de calidad, el mantenimiento del medio ambiente y la dignificación del hombre rural. El objetivo de la ingeniería agrícola es la generación y aplicación de conocimientos científicos y tecnológicos de la ingeniería a la producción agropecuaria y otros biosistemas orientados a las áreas de adecuación de tierras, maquinaria agrícola, manejo de recursos hídricos, construcciones rurales, manejo poscosecha y procesamiento de producto agropecuarios, con criterios de sostenibilidad y competitividad.

  18. AGR-2 Data Qualification Report for ATR Cycles 151B-2, 152A, 152B, 153A, 153B and 154A

    Energy Technology Data Exchange (ETDEWEB)

    Binh T. Pham; Jeffrey J. Einerson

    2013-09-01

    This report documents the data qualification status of AGR-2 fuel irradiation experimental data from Advanced Test Reactor (ATR) Cycles 152A, 152B, 153A, 153B, and 154A, as recorded in the Nuclear Data Management and Analysis System (NDMAS). The AGR-2 data streams addressed include thermocouple (TC) temperatures, sweep gas data (flow rate, pressure, and moisture content), and fission product monitoring system (FPMS) data for each of the six capsules in the experiment. A total of 13,400,520 every minute instantaneous TC and sweep gas data records were received and processed by NDMAS for this period. Of these data, 8,911,791 records (66.5% of the total) were determined to be Qualified based on NDMAS accuracy testing and data validity assessment. For temperature, there were 4,266,081 records (74% of the total TC data) that were Failed due to TC instrument failures. For sweep gas flows, there were 222,648 gas flow records (2.91% of the flow data) that were Failed. The inlet gas flow failures due to gas flow cross-talk and leakage problems that occurred after Cycle 150A were corrected by using the same gas mixture in all six capsules and the Leadout. For FPMS data, NDMAS received and processed preliminary release rate and release-to-birth rate ratio (R/B) data for three reactor cycles (Cycles 149B, 150B, and 151A) . This data consists of 45,983 release rate records and 45,235 R/B records for the 12 radionuclides reported. The qualification status of these FPMS data has been set to In Process until receipt of Quality Assurance-approved data generator reports. All of the above data have been processed and tested using a SAS®-based enterprise application software system, stored in a secure Structured Query Language database, made available on the NDMAS Web portal (http://ndmas.inl.gov), and approved by the INL STIM for release to both internal and appropriate external Very High Temperature Reactor Program participants.

  19. Modelling 3D crack propagation in ageing graphite bricks of Advanced Gas-Cooled Reactor Power Plant

    International Nuclear Information System (INIS)

    In this paper, crack propagation in Advanced Gas-cooled Reactor (AGR) graphite bricks with ageing properties is studied using the eXtended Finite Element Method (X-FEM). A parametric study for crack propagation, including the influence of different initial crack shapes and propagation criteria, is conducted. The results obtained in the benchmark study show that the crack paths from X-FEM are similar to the experimental ones. The accuracy of the strain energy release rate computation in a heterogeneous material is also evaluated using a finite difference approach. Planar and non-planar 3D crack growth simulations are presented to demonstrate the robustness and the versatility of the method utilized. Finally, this work contributes to the better understanding of crack propagation behaviour in AGR graphite bricks and so contributes to the extension of the AGR plant lifetimes in the UK by reducing uncertainties. (author)

  20. A reforma agrária no segundo mandato de Fernando Henrique Cardoso

    Directory of Open Access Journals (Sweden)

    José de Souza Martins

    2003-11-01

    Full Text Available Já no primeiro mandato do presidente Fernando Henrique Cardoso, a política agrária sofreu reorientações significativas, que marcariam seu segundo mandato, a partir da nomeação de Raul Jungmann como ministro do Desenvolvimento Agrário. A reforma agrária finalmente encontrou o seu sujeito, a agricultura familiar, e o Estado encontrou a sua missão agrária como gestor do território. Foram assim estabelecidas as bases concretas para o exercício da função social da propriedade, recuperando o Estado, na prática, o domínio eminente do território do país. Importante providência nesse sentido foi a anulação dos títulos irregulares de propriedade de sessenta milhões de hectares de terra. O governo firmou a prerrogativa do Estado de "rotinizar" a redistribuição da terra concentrada e regular e assegurar o direito de propriedade em associação com a dupla alternativa de dois modelos agrícolas conviventes: o agronegócio e a agricultura familiar.During Fernando Henrique Cardoso's first term in office, the agrarian policy underwent significant changes that marked his second term, as of when Raul Jungmann was appointed Minister of Agricultural Development. Agrarian reform finally encountered its subject, subsistence crop farming, and the State found its agrarian mission as manager of the territory. Thus, the concrete foundations for the exercise of the social function of landownership were established, and the State recovered, in practice, the eminent domination of the country's territory. One of the important provisions was the annulment of irregular land deeds regarding 60 million hectares. The government determined it to be the prerogative of the State to make routine redistribution of concentrated land and to regulate and assure landownership rights associated to the double alternatives of two cohabitating agricultural models: agro-business and subsistence farming.

  1. Reactor Physics

    International Nuclear Information System (INIS)

    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

  2. Reactor Physics

    International Nuclear Information System (INIS)

    SCK-CEN's Reactor Physics and MYRRHA Department offers expertise in various areas of reactor physics, in particular in neutron and gamma calculations, reactor dosimetry, reactor operation and control, reactor code benchmarking and reactor safety calculations. 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 materials testing 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 2001 are summarised

  3. 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.

  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. Reactor safeguards

    CERN Document Server

    Russell, Charles R

    2013-01-01

    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

  6. Research Reactors

    Energy Technology Data Exchange (ETDEWEB)

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

    1968-09-01

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

  7. Listeria monocytogenes differential transcriptome analysis reveals temperature-dependent Agr regulation and suggests overlaps with other regulons.

    Directory of Open Access Journals (Sweden)

    Dominique Garmyn

    Full Text Available Listeria monocytogenes is a ubiquitous, opportunistic pathogenic organism. Environmental adaptation requires constant regulation of gene expression. Among transcriptional regulators, AgrA is part of an auto-induction system. Temperature is an environmental cue critical for in vivo adaptation. In order to investigate how temperature may affect AgrA-dependent transcription, we compared the transcriptomes of the parental strain L. monocytogenes EGD-e and its ΔagrA mutant at the saprophytic temperature of 25°C and in vivo temperature of 37°C. Variations of transcriptome were higher at 37°C than at 25°C. Results suggested that AgrA may be involved in the regulation of nitrogen transport, amino acids, purine and pyrimidine biosynthetic pathways and phage-related functions. Deregulations resulted in a growth advantage at 37°C, but affected salt tolerance. Finally, our results suggest overlaps with PrfA, σB, σH and CodY regulons. These overlaps may suggest that through AgrA, Listeria monocytogenes integrates information on its biotic environment.

  8. Programa computacional para calcular a potência requerida de máquinas e implementos agrícolas

    Directory of Open Access Journals (Sweden)

    Pablo Pereira Corrêa Klaver

    2013-12-01

    Full Text Available O uso de programas computacionais no setor agrícola permite atingir objetivos específicos na área. Dentre esses, um dos mais complexos é a seleção adequada de máquinas e implementos agrícolas visando à otimização de operações agrícolas, devido, principalmente, à grande variedade de equipamentos existentes no mercado e a gama de tarefas e situações de trabalho que estas são submetidas no campo. O objetivo deste trabalho foi desenvolver um programa computacional para calcular a potência requerida de máquinas e implementos agrícolas normalmente utilizados na condução de operações de campo, desde o preparo do solo até as operações de implantação de culturas. Desenvolvido em linguagem PHP, o programa computacional baseia-se na norma ASAE D497.4 - Agricultural Machinery Management Data como referência para desenvolvimento de cálculos. A partir do programa desenvolvido, tornou-se possível a execução de tarefas para cálculos de avaliação da demanda de potência de máquinas e implementos agrícolas de forma simplificada pela internet.

  9. Human oral isolate Lactobacillus fermentum AGR1487 induces a pro-inflammatory response in germ-free rat colons.

    Science.gov (United States)

    Anderson, Rachel C; Ulluwishewa, Dulantha; Young, Wayne; Ryan, Leigh J; Henderson, Gemma; Meijerink, Marjolein; Maier, Eva; Wells, Jerry M; Roy, Nicole C

    2016-01-01

    Lactobacilli are thought to be beneficial for human health, with lactobacilli-associated infections being confined to immune-compromised individuals. However, Lactobacillus fermentum AGR1487 negatively affects barrier integrity in vitro so we hypothesized that it caused a pro-inflammatory response in the host. We compared germ-free rats inoculated with AGR1487 to those inoculated with another L. fermentum strain, AGR1485, which does not affect in vitro barrier integrity. We showed that rats inoculated with AGR1487 had more inflammatory cells in their colon, higher levels of inflammatory biomarkers, and increased colonic gene expression of pro-inflammatory pathways. In addition, our in vitro studies showed that AGR1487 had a greater capacity to activate TLR signaling and induce pro-inflammatory cytokines in immune cells. This study indicates the potential of strains of the same species to differentially elicit inflammatory responses in the host and highlights the importance of strain characterization in probiotic approaches to treat inflammatory disorders. PMID:26843130

  10. hidráulicos de las máquinas agrícolas

    Directory of Open Access Journals (Sweden)

    Luciano Pérez Sobrevilla

    2006-01-01

    Full Text Available Como parte de las investigaciones que se llevan a cabo en la Universidad Autónoma Chapingo de México, en el Departamento de Ingeniería Mecánica Agrícola (DIMA y en la Universidad Agraria de La Habana, en el Centro de Mecanización Agropecuaria (CEMA, dirigidas al estudio de la Oleohidráulica y fundamentados en los resultados de una investigación, se elaboran recomendaciones sobre la utilización de aceites recuperados y su explotación racional en los sistemas hidráulicos de las máquinas agrícolas, partiendo de que el aceite hidráulico recuperado mostró la misma susceptibilidad a la contaminación que el aceite hidráulico nuevo, durante todo el período de observación. De esta forma y con los resultados encontrados se debe mostrar al usuario los beneficios que pueden significar el uso de aceites reciclados, tanto para su economía como para la reducción de la contaminación del medio ambiente. De acuerdo con lo anterior se pretende: introducir el uso de un equipo de recuperación de aceites hidráulicos en el Laboratorio de Hidráulica y Neumática del DIMA (LAHNDI, para recuperar aceites hidráulicos residuales, mediante un proceso de centrifugación y filtración, para de esta forma reducir el costo de producción de los aceites hidráulicos utilizados en máquinas agrícolas e industriales.

  11. Sistemas de producción agrícola sostenible

    Directory of Open Access Journals (Sweden)

    Róger Martínez Castillo

    2009-01-01

    Full Text Available El desarrollo sostenible se fundamenta en principios éticos, como el respeto y armonía con la naturaleza; valores políticos, como la democracia participativa y equidad social; y normas morales, como racionalidad ambiental. El desarrollo sostenible es igualitario, descentralizado y autogestionario, capaz de satisfacer las necesidades básicas de la población, respetando la diversidad cultural y mejorando la calidad de vida. La agricultura y el desarrollo sostenible se refieren a la necesidad de minimizar la degradación de la tierra agrícola, maximizando a su vez la producción. Este considera el conjunto de las actividades agrícolas, como el manejo de suelos y aguas,el manejo de cultivos y la conservación de la biodiversidad; considerando a su vez el suministro de alimentos y materias primas. La sostenibilidad de los sistemas de producción agrícola se refiere a la capacidad del sistema para mantener su productividad a pesar de las perturbaciones económicas y naturales, externas o internas. La sostenibilidad es función de las características naturales del sistema y las presiones e intervenciones que sufre, así como aquellas intervenciones sociales, económicas y técnicas que se hacen para contrarrestar presiones negativas; destacándose la resiliencia del sistema.

  12. Readiness Review of BWXT for Fabrication of AGR-5/6/7 TRISO Particles

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, Douglas William [Idaho National Lab. (INL), Idaho Falls, ID (United States); Sharp, Michelle Tracy [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-02-01

    INL readiness review assessment of BWXT readiness to commence fabrication of low-enriched TRISO coated fuel particles for the AGR-5/6/7 irradiation experiments. BWXT self-identified equipment issues preventing operation. INL identified two findings. The first was that disposition codes had not been assigned and documented on BWXT forms to ensure that off-specification materials could not be used in the fabrication of TRISO particles. The second was that chemical purity specifications were not reliably passed on to chemical suppliers, which resulted in the receipt of one acetylene cylinder with suspect impurity levels.

  13. Agroecologia: um caminho multidimensional para o desenvolvimento agrário do Litoral Paranaense.

    OpenAIRE

    Borsatto, Ricardo Serra

    2007-01-01

    Ao se estudar o meio agrário do litoral paranaense é fácil constatar as dificuldades que este enfrenta para encontrar um caminho que permita o seu desenvolvimento sustentável. A presente dissertação visa contribuir nas discussões e consequentemente na procura de soluções para este panorama, objetivando conhecer e discutir se o conhecimento gerado pela Agroecologia pode contribuir para o desenvolvimento sustentável do litoral paranaense. Para tanto é utilizada a teoria do pensamento complexo, ...

  14. Sinopsis de Membracidae (Hemiptera: Membracoidea) de Colombia, relacionados con ecosistemas agrícolas

    OpenAIRE

    González Mozo, Laura Catalina

    2014-01-01

    Los Membracidae son insectos chupadores de savia en una gran variedad de especies vegetales silvestres y de importancia agrícola, como cultivos o árboles de sombrío. Las especies de esta familia se reconocen por la modificación del pronoto, al formar un casco dorsal. En los Membrácidos se conocen además relaciones ecológicas de simbiosis con himenópteros trofobiontes. En estas asociaciones, los himenópteros se alimentan del rocío de miel que producen los Membracidae y a su vez protegen a esto...

  15. Research reactors

    International Nuclear Information System (INIS)

    This article proposes an overview of research reactors, i.e. nuclear reactors of less than 100 MW. Generally, these reactors are used as neutron generators for basic research in matter sciences and for technological research as a support to power reactors. The author proposes an overview of the general design of research reactors in terms of core size, of number of fissions, of neutron flow, of neutron space distribution. He outlines that this design is a compromise between a compact enough core, a sufficient experiment volume, and high enough power densities without affecting neutron performance or its experimental use. The author evokes the safety framework (same regulations as for power reactors, more constraining measures after Fukushima, international bodies). He presents the main characteristics and operation of the two families which represent almost all research reactors; firstly, heavy water reactors (photos, drawings and figures illustrate different examples); and secondly light water moderated and cooled reactors with a distinction between open core pool reactors like Melusine and Triton, pool reactors with containment, experimental fast breeder reactors (Rapsodie, the Russian BOR 60, the Chinese CEFR). The author describes the main uses of research reactors: basic research, applied and technological research, safety tests, production of radio-isotopes for medicine and industry, analysis of elements present under the form of traces at very low concentrations, non destructive testing, doping of silicon mono-crystalline ingots. The author then discusses the relationship between research reactors and non proliferation, and finally evokes perspectives (decrease of the number of research reactors in the world, the Jules Horowitz project)

  16. Reactor physics and reactor computations

    International Nuclear Information System (INIS)

    Mathematical methods and computer calculations for nuclear and thermonuclear reactor kinetics, reactor physics, neutron transport theory, core lattice parameters, waste treatment by transmutation, breeding, nuclear and thermonuclear fuels are the main interests of the conference

  17. Research reactors

    International Nuclear Information System (INIS)

    There are currently 284 research reactors in operation, and 12 under construction around the world. Of the operating reactors, nearly two-thirds are used exclusively for research, and the rest for a variety of purposes, including training, testing, and critical assembly. For more than 50 years, research reactor programs have contributed greatly to the scientific and educational communities. Today, six of the world's research reactors are being shut down, three of which are in the USA. With government budget constraints and the growing proliferation concerns surrounding the use of highly enriched uranium in some of these reactors, the future of nuclear research could be impacted

  18. Reactor container

    International Nuclear Information System (INIS)

    Object: To provide a jet and missile protective wall of a configuration being inflated toward the center of a reactor container on the inside of a body of the reactor container disposed within a biological shield wall to thereby increase safety of the reactor container. Structure: A jet and missile protective wall comprised of curved surfaces internally formed with a plurality of arch inflations filled with concrete between inner and outer iron plates and shape steel beam is provided between a reactor container surrounded by a biological shield wall and a thermal shield wall surrounding the reactor pressure vessel, and an adiabatic heat insulating material is filled in space therebetween. (Yoshino, Y.)

  19. Relaciones de largo plazo entre el sector agrícola y el no agrícola: un estudio de cointegración para la economía peruana

    OpenAIRE

    Javier Escobal

    1993-01-01

    La evidencia internacional indica que existe cointegración en el largo plazo entre el producto agrícola y el producto no-agrícola para una serie de países. Este artículo intenta probar la validez de tal afirmación para el caso peruano, empleando para ello series anuales para estas variables desde principios de siglo. La contrastación empírica que se lleva a cabo sugiere la existencia de un vector de cointegración desde 1917 hasta 1959 aproximadamente. A partir de esta fecha la relación de coi...

  20. Trabajadores agrícolas migrantes en Baja California. Vinculación con la migración internacional

    Directory of Open Access Journals (Sweden)

    Ma. Eugenia Anguiano Téllez

    1989-09-01

    Full Text Available En este ensayo los jornaleros agrícolas migrantes son clasificados en dos estratos: el primero, considera la migración internacional, es decir, aquéllos que se internan en Estados Unidos con el propósito de conseguir empleo; y el segundo, corresponde a la migración interna de los trabajadores agrícolas que permanecen en Baja California para laborar en los valles de Mexicali y San Quintín.En este trabajo se señalan las diferencias entre estos dos estratos, tanto de carácter económico como en los niveles de educación; asimismo, se comparan las características de los jornaleros agrícolas migrantes que cruzan a Estados Unidos por Mexicali y por Tijuana, según su actividad económica de procedencia y su expectativa de empleo en los Estados Unidos.

  1. The agr Inhibitors Solonamide B and Analogues Alter Immune Responses to Staphylococccus aureus but Do Not Exhibit Adverse Effects on Immune Cell Functions

    DEFF Research Database (Denmark)

    Baldry, Mara; Kitir, Betül; Frøkiær, Hanne;

    2016-01-01

    with agr, while immune cell activity and integrity is generally not affected. Furthermore, treatment of S. aureus with selected solonamides was found to only marginally influence the interaction with fibronectin and biofilm formation, thus addressing the concern that application of compounds inducing...... an agr-negative state may have adverse interactions with host factors in favor of host colonization....

  2. La industria de maquinaria agrícola en Argentina frente a la estructura sectorial del mercado internacional

    OpenAIRE

    Langard, Federico

    2011-01-01

    En el marco de una continua reestructuración de las empresas trasnacionales productoras de maquinaria agrícola a nivel mundial, se observa una, significativa tendencia a la concentración de las mismas y a la oligopolización de la oferta mundial, situación que sin lugar a dudas impacta en nuestro país. El trabajo analiza la dinámica del comercio mundial de maquinaria agrícola, vinculada al desempeño del sector en Argentina. Para ello, se examina el comportamiento de las firmas nacionales y ext...

  3. Evaluación de residuos agrícolas para la producción del hongo Pleurotus ostreatus

    OpenAIRE

    María Bernarda Ruilova Cueva; Aldo Hernández Monzón

    2014-01-01

    Se caracterizaron los residuos agrícolas de la provincia de Bolívar, Ecuador, desde el punto de vista de su composición físico-química para su empleo en el cultivo del hongo Pleurotus ostreatus. Los residuos agrícolas utilizados fueron: maíz, trigo, cebada, lenteja, bagazo de caña de azúcar y cascarilla de arroz. Se realizaron análisis de: humedad, cenizas, extracto etéreo, proteína, fibra, extracto libre de nitrógeno, fibra detergente neutra, fibra detergente ácida, lignina, celulosa, hemice...

  4. Huella hídrica de productos agrícolas producidos en la sierra central y comercializados en Lima

    OpenAIRE

    Tito Mallma Capcha; Jesús Mejía Marcacuzco

    2015-01-01

    El objetivo ha sido determinar un modelo para obtener la huella hídrica de los principales productos agrícolas de la sierra central del Perú que son comercializados en los mercados de la ciudad de Lima, para ello se desarrolló un modelo conceptual que determine el requerimiento de agua de los cultivos que junto a los respectivos rendimientos han permitido establecer el contenido de agua virtual de cada producto agrícola expresado en l/kg; con este resultado y la cantidad de producto comercial...

  5. Unidades integrales de servicios técnicos de maquinaria agrícola

    Directory of Open Access Journals (Sweden)

    José Suárez

    2011-01-01

    Full Text Available En cada municipio cubano se inició la creación de centros encargados de prestar servicios de mecanización agrícola y asistencia técnica a los productores. Para esto deben disponer de tractores, cosechadoras y otras máquinas e implementos propios, así como de talleres para la reparación y mantenimiento. Cada uno de estos centros será una Unidad Integral de Servicios Técnicos (UIST con el carácter de Unidad Empresarial de Base (UEB subordinada a la Empresa Agropecuaria Municipal. Para constituir estas Unidades fue necesario realizar un estudio de la disponibilidad de talleres, equipamiento, maquinaria y personal de mecanización en las empresas agrícolas y otras entidades productivas de todos los municipios del país, pues ellos constituirán el núcleo fundamental del nuevo sistema. Se ha conformado la propuesta del esquema de funcionamiento de las Unidades, especialmente en lo que respecta a áreas, funciones, equipamiento, modelo de gestión, contratación de servicios, planificación, organización, control, relaciones con otras entidades productivas y de dirección, etc. Estas Unidades se están creando en municipios seleccionados, con vistas a evaluar los resultados, y, teniendo en cuenta las experiencias obtenidas, conformar el programa para extender el sistema a todo el país.

  6. Completing the Design of the Advanced Gas Reactor Fuel Development and Qualification Experiments for Irradiation in the Advanced Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    S. Blaine Grover

    2006-10-01

    The United States Department of Energy’s Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating eight separate low enriched uranium (LEU) oxycarbide (UCO) tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the newly formed Idaho National Laboratory (INL). These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States. The ATR has a long history of irradiation testing in support of reactor development and the INL has been designated as the new United States Department of Energy’s lead laboratory for nuclear energy development. The ATR is one of the world’s premiere test reactors for performing long term, high flux, and/or large volume irradiation test programs. These AGR fuel experiments will be irradiated over the next ten years to demonstrate and qualify new particle fuel for use in high temperature gas reactors. The goals of the irradiation experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing. The experiments, which will each consist of six separate capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control for each capsule. The swept gas will also have on-line fission product monitoring to track performance of the fuel in each individual capsule during irradiation.

  7. Completing the Design of the Advanced Gas Reactor Fuel Development and Qualification Experiments for Irradiation in the Advanced Test Reactor

    International Nuclear Information System (INIS)

    The United States Department of Energy's Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating eight separate low enriched uranium (LEU) oxycarbide (UCO) tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the newly formed Idaho National Laboratory (INL). These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States. The ATR has a long history of irradiation testing in support of reactor development and the INL has been designated as the new United States Department of Energy's lead laboratory for nuclear energy development. The ATR is one of the world's premiere test reactors for performing long term, high flux, and/or large volume irradiation test programs. These AGR fuel experiments will be irradiated over the next ten years to demonstrate and qualify new particle fuel for use in high temperature gas reactors. The goals of the irradiation experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing. The experiments, which will each consist of six separate capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control for each capsule. The swept gas will also have on-line fission product monitoring to track performance of the fuel in each individual capsule during irradiation

  8. Una aproximación a las características actuales de la mano de obra agrícola en el valle de Mexicali

    Directory of Open Access Journals (Sweden)

    José Ascención Moreno Mena

    1994-07-01

    Full Text Available Este trabajo aborda, de manera sintética, algunas características de la estructura agraria, así como de productores agrícolas del valle de Mexicali. Se presenta un acercamiento a las condiciones en que se desarrolla la mano de obra actual en el sector agrícola del municipio de Mexicali. Para ello se toma como base información primaria obtenida de dos encuestas realizadas durante el periodo 1991-1994; laprimera producto de un muestreo no aleatorio por cuotas aplicada a 150 trabajadores agrícolas del algodón; y la segunda de carácter aleatoria aplicada en 499 viviendas de trabajadores agrícolas en el valle de Mexicali por el Instituto de investigaciones Sociales de la Universidad Autónoma de Baja California y el Programa Nacional de Solidaridad con Jornaleros Agrícolas.

  9. The inverse kinetics technique for reactor shutdown measurement -an experimental assessment

    International Nuclear Information System (INIS)

    It is proposed to use the Inverse Kinetics Technique to measure the subcritical reactivity as a function of time during the testing of the nitrogen injection systems on AGRs. An experimental assessment of the technique by investigating known transients created by control rod movements on a small (2m high, 1m radius) experimental reactor is described. Spatial effects were observed close to the moving rods but otherwise derived reactivities were independent of detector position and agreed well with the existing calibrations. This prompted the suggestion that data from installed reactor instrumentation could be used to calibrate CAGR control rods. (author)

  10. Reactor building

    International Nuclear Information System (INIS)

    The whole reactor building is accommodated in a shaft and is sealed level with the earth's surface by a building ceiling, which provides protection against penetration due to external effects. The building ceiling is supported on walls of the reactor building, which line the shaft and transfer the vertical components of forces to the foundations. The thickness of the walls is designed to withstand horizontal pressure waves in the floor. The building ceiling has an opening above the reactor, which must be closed by cover plates. Operating equipment for the reactor can be situated above the building ceiling. (orig./HP)

  11. Heterogeneous reactors

    International Nuclear Information System (INIS)

    The microscopic study of a cell is meant for the determination of the infinite multiplication factor of the cell, which is given by the four factor formula: K(infinite) = n(epsilon)pf. The analysis of an homogeneous reactor is similar to that of an heterogeneous reactor, but each factor of the four factor formula can not be calculated by the formulas developed in the case of an homogeneous reactor. A great number of methods was developed for the calculation of heterogeneous reactors and some of them are discussed. (Author)

  12. Status of national gas cooled reactor programmes

    International Nuclear Information System (INIS)

    This report has been compiled as a central source of summary-level information on the present status of High Temperature Gas-Cooled Reactor (HTGR) programmes in the world and on future plans for the continued development and deployment of HTGRs. Most of the information concerns the programmes in the United States, Germany, Japan and the Soviet Union, countries that have had large programmes related to HTGR technology for several years. Summary-level information is also provided in the report on HTGR-related activities in several other countries who either have an increasing interest in the technology and/or who are performing some development efforts related to HTGR technology. The report contains a summary-level update on the MAGNOX and AGR programmes. This is the twelfth issue of the document, the first of which was issued in March, 1979. The report has been prepared in the IAEA Nuclear Power Technology Development Section. Figs and tabs

  13. Safety and dose management during decommissioning of a fire damaged nuclear reactor

    International Nuclear Information System (INIS)

    Windscale Piles 1 and 2 in Cumbria in the UK were constructed in the early 1950s. They were not intended to produce electricity but were for military purposes only. They were graphite-moderated, air-cooled reactors with horizontal fuel channels fuelled with uranium rods clad in finned aluminium. In October 1957, Windscale Pile 1 suffered a core fire during a planned release of Wigner energy and both Piles were subsequently closed down. Following the fire, Pile 2 was defuelled entirely and as much fuel as was possible was removed from Pile 1. However, it is estimated that up to 15 Te of fuel remains in the core, a large proportion of which is located in the central Fire Affected Zone (FAZ). The condition of the fuel and graphite moderator in the FAZ is not known. It is possible that the moderator could contain voidage, greatly reduced density graphite and fused materials in a disordered matrix. It is probable that there is residual Wigner energy in the graphite. Use of water as part of the attempt to extinguish the fire, together with the possibility that the solidification of molten materials or other local sealing mechanisms could have excluded air mean that uranium hydrides, carbides and other pyrophorics may be present within the core. Pile 1 is now being decommissioned and a considerable amount of preparatory work has already been carried out during Phase 1. Phase 2 decommissioning, which will remove the residual fuel, the moderator and associated steelwork, condition the wastes and place them in a purpose built store is now underway. This work will be carried out for the site licensee, the United Kingdom Energy Authority, by a consortium of British Nuclear Fuels plc, Rolls Royce and NUKEM. This paper will describe the methods to be used to decommission Pile 1 and the systems and procedures which will be used to ensure that it is done safely and with the lowest reasonably practicable environmental impact. It will also describe the methods which will be used to

  14. Plasma reactor

    OpenAIRE

    Molina Mansilla, Ricardo; Erra Serrabasa, Pilar; Bertrán Serra, Enric

    2008-01-01

    [EN] A plasma reactor that can operate in a wide pressure range, from vacuum and low pressures to atmospheric pressure and higher pressures. The plasma reactor is also able to regulate other important settings and can be used for processing a wide range of different samples, such as relatively large samples or samples with rough surfaces.

  15. Reactor physics

    International Nuclear Information System (INIS)

    Progress in research on reactor physics in 1997 at the Belgian Nuclear Research Centre SCK/CEN is described. Activities in the following four domains are discussed: core physics, ex-core neutron transport, experiments in Materials Testing Reactors, international benchmarks

  16. Maximum permissible dietary contamination after the accidental release of radioactive materials from a nuclear reactor

    International Nuclear Information System (INIS)

    After the accident to No. 1 pile at Windscale on October 10, 1957 (Atomic Energy Office, 1957), the Atomic Energy Authority asked the Medical Research Council for advice on the maximum intake of certain radioactive isotopes that should be regarded as permissible, under emergency conditions, for members of the general population living in, or deriving food from, an area contaminated owing to an accident to a reactor. The Council's Committee on Protection against Ionizing Radiations, together with its Subcommittees on Internal and External Radiations, has considered this problem, and concludes that the intake of radioactive materials by ingestion of contaminated food would generally be the limiting source of hazard after any such accident. Intake by inhalation, or radiation from the exterior, would become of importance only in rather special circumstances. In the following report, therefore, the Committee proposes maximum permissible levels of dietary contamination for the relevant isotopes in the emergency conditions envisaged. In proposing these levels, the Protection Committee has used the fullest information available on the radiation doses that would be delivered to different body tissues and at different ages by the isotopes concerned, and on the ways in which these materials would enter the body

  17. Specialists' meeting on gas-cooled reactor core and high temperature instrumentation, Windermere, UK, 15-17 June 1982. Summary report

    International Nuclear Information System (INIS)

    The Specialists' Meeting on ''Gas-Cooled Reactor Core and High Temperature Instrumentation'' was held at the Beech Hill Hotel, Windermere in England on June 15-17 1982. The meeting was sponsored by the IAEA on the recommendation of the International Working Group on Gas Cooled Reactors and was hosted by the Windscale Nuclear Power Development Laboratories of the UKAEA. The meeting was attended by 43 participants from Belgium, France, Federal Republic of Germany, Japan, United Kingdom of Great Britain and Northern Ireland and the United States of America. The objective of the meeting was to provide a forum, both formal and informal, for the exchange and discussion of technical information relating to instrumentation being used or under development for the measurement of core parameters, neutron flux, temperature, coolant flow etc. in gas cooled reactors. The technical part of the meeting was divided into five subject sessions: (A) Temperature Measurement (B) Neutron Detection Instrumentation (C) HTR Instrumentation - General (D) Gas Analysis and Failed Fuel Detection (E) Coolant Mass Flow and Leak Detection. A total of twenty-five papers were presented by the participants on behalf of their organizations during the meeting. A programme of the meeting and list of participants are given in appendices to this report

  18. AGR-1 Compact 4-1-1 Post-Irradiation Examination Results

    Energy Technology Data Exchange (ETDEWEB)

    Demkowicz, Paul Andrew [Idaho National Lab. (INL), Idaho Falls, ID (United States); Harp, Jason M. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Winston, Philip L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ploger, Scott A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); van Rooyen, Isabella J. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-02-01

    Destructive post-irradiation examination was performed on AGR-1 fuel Compact 4-1-1, which was irradiated to a final compact-average burnup of 19.4% FIMA (fissions per initial metal atom) and a time-average, volume-average temperature of 1072°C. The analysis of this compact focused on characterizing the extent of fission product release from the particles and examining particles to determine the condition of the kernels and coating layers. The work included deconsolidation of the compact and leach-burn-leach analysis, visual inspection and gamma counting of individual particles, metallurgical preparation of selected particles, and examination of particle cross-sections with optical microscopy, electron microscopy, and elemental analysis. Deconsolidation-leach-burn-leach (DLBL) analysis revealed no particles with failed TRISO or failed SiC layers (as indicated by very low uranium inventory in all of the leach solutions). The total fractions of the predicted compact inventories of fission products Ce-144, Cs-134, Cs-137, and Sr-90 that were present in the compact outside of the SiC layers were <2×10-6, based on DLBL data. The Ag-110m fraction in the compact outside the SiC layers was 3.3×10-2, indicating appreciable release of silver through the intact coatings and subsequent retention in the OPyC layers or matrix. The Eu-154 fraction was 2.4×10-4, which is equivalent to the inventory in one average particle, and indicates a small but measurable level of release from the intact coatings. Gamma counting of 61 individual particles indicated no particles with anomalously low fission product retention. The average ratio of measured inventory to calculated inventory was close to a value of 1.0 for several fission product isotopes (Ce-144, Cs-134, and Cs-137), indicating good retention and reasonably good agreement with the predicted inventories. Measured-to-calculated (M/C) activity ratios for fission products Eu-154, Eu-155, Ru-106, Sb

  19. Ingeniería agrícola, una alternativa para las necesidades del agro

    OpenAIRE

    Julio E. Ospina M.; Jaime Salazar Contreras

    2011-01-01

    La ingeniería agrícola como profesión que articula los conceptos de la ingeniería y los procesos biológicos, está llamada a desempeñar un papel protagónico en el desarrollo del campo colombiano. Por ello requerimos espacio político para poder hacer parte de los estamentos de decisión y difundir estrategias en: - Control de erosión. - Desarrollo de tecnología apropiada a través de la investigación en las universidades colombianas. - Racionalización de las pérdidas en frutas, hortalizas y cerea...

  20. Ingeniería agrícola, una alternativa para las necesidades del agro

    Directory of Open Access Journals (Sweden)

    Julio E. Ospina M.

    2011-02-01

    Full Text Available La ingeniería agrícola como profesión que articula los conceptos de la ingeniería y los procesos biológicos, está llamada a desempeñar un papel protagónico en el desarrollo del campo colombiano. Por ello requerimos espacio político para poder hacer parte de los estamentos de decisión y difundir estrategias en: - Control de erosión. - Desarrollo de tecnología apropiada a través de la investigación en las universidades colombianas. - Racionalización de las pérdidas en frutas, hortalizas y cereales, entre otros".

  1. Modelo de Precificação de Capital: Segmento de Commodities Agrícola

    Directory of Open Access Journals (Sweden)

    TÁCITO AUGUSTO FARIAS

    2014-12-01

    Full Text Available O objetivo do artigo é a aplicação do modelo de precificação de ativos conhecido na literatura de economia financeira como CAPITAL ASSET PRICING MODEL – MODELO DE PRECIFICAÇÃO DE ATIVOS DE CAPITAL, utilizando como ferramentas os balanços patrimoniais das empresas selecionadas. Brasil Ecodiesel indústria e comercio de biocombustíveis e óleos vegetais s.a. (v-agro e SLC Agrícola s.a. no período relativo ao ano de 2009 e 2010. Resultado fundamental: ambas as empresas no período em estudo apresentaram um beta inferior a 1, ou seja, risco menor que o risco do mercado. Descrevemos alguns resultados estatísticos que mostram o comportamento de ambas as empresas do setor de frigorifico. 

  2. Underwater examination of irradiated AGR fuel elements in power station cooling ponds

    International Nuclear Information System (INIS)

    Mobile equipment has been developed for the on-site underwater inspection of fuel elements discharged from Nuclear Electric's AGR Power Stations. High quality macroscopic images of the fuel pins are obtained using a rigid endoscopic probe coupled to a TV camera. This paper sets out the reasons why on-site endoscopy is particularly valuable, describes in-pond operations and provides details of the optical system employed. The equipment is used to obtain numerical data relevant to fuel performance. In particular, image detail can be interpreted to assess the thickness of deposition, sometimes present on pins. Clad collapse and fuel pin length changes can also be quantified. The techniques used, and their calibration, are outlined. Operational experiences over the past three years is reviewed. (author)

  3. Monitoring and performance analysis of AGR boilers during commissioning and power raising

    International Nuclear Information System (INIS)

    The installed boiler plant, for two 1300 MW AGR stations, is comprehensively instrumented for boiler control, performance assessment and component monitoring to ensure the integrity and safe operation of the plant during normal and faulty operating conditions. Plant instrumentation and computer systems installed at site for vibration analysis during the engineering runs and data acquisition during the power raising stage have been described. The results, from early rig investigations and the vibration testing during the unfueled engineering runs, indicate that the behaviour of the plant within the practical range of operating conditions is free from vibration problems. Also the analysis of the steady state thermal and hydrodynamic behaviour of the boiler plant during the power raising phase confirms the methods and computer models used for the boiler design. (author)

  4. Productividad del agua en algunos cultivos agrícolas en Cuba

    Directory of Open Access Journals (Sweden)

    Felicita González Robaina

    2014-01-01

    Full Text Available Para el mejor uso económico y social del agua se requieren de métodos para evaluar su productividad, a fin de tomar mejores decisiones en cuanto a políticas y estrategias de utilización de manera sostenible. Los administradores del agua para el riego necesitan iden- tificar tendencias en los patrones de uso y niveles de eficiencia con vistas a fijar metas y mejorar la productividad por unidad de volumen utilizado y/o consumido. El objetivo de este trabajo fue presentar los indicadores de productividad agronómica del agua de 17 cultivos a partir de la información obtenida en más de 100 experimentos de campo disponibles en la base de datos sobre necesidades hídricas del Instituto de Investigaciones de Ingeniería Agrícola. Se determinaron los rendimientos máximo y mínimo y sus respectivos valores de consumo, agua aplicada por riego y la productividad agronómica del agua aplicada para los 17 cultivos estudiados. Cultivos como los frijoles, maíz, boniato y los plátanos obtienen incrementos de rendimiento superiores al 100% cuando se aplica el agua necesaria para satisfacer su demanda hídrica, mientras que la yuca obtuvo valores menores del 50%. Los altos valores obtenidos de productividad en base al agua utilizada como riego no son un buen indicador del uso eficiente del agua por las plantas para las condiciones de la zona de estudio, donde se informan para los años analizados, porcentajes de lluvia aprovechable de hasta el 41%, supliendo ésta una parte importante de las necesidades de los cultivos agrícolas.

  5. Compact Reactor

    International Nuclear Information System (INIS)

    Weyl's Gauge Principle of 1929 has been used to establish Weyl's Quantum Principle (WQP) that requires that the Weyl scale factor should be unity. It has been shown that the WQP requires the following: quantum mechanics must be used to determine system states; the electrostatic potential must be non-singular and quantified; interactions between particles with different electric charges (i.e. electron and proton) do not obey Newton's Third Law at sub-nuclear separations, and nuclear particles may be much different than expected using the standard model. The above WQP requirements lead to a potential fusion reactor wherein deuterium nuclei are preferentially fused into helium nuclei. Because the deuterium nuclei are preferentially fused into helium nuclei at temperatures and energies lower than specified by the standard model there is no harmful radiation as a byproduct of this fusion process. Therefore, a reactor using this reaction does not need any shielding to contain such radiation. The energy released from each reaction and the absence of shielding makes the deuterium-plus-deuterium-to-helium (DDH) reactor very compact when compared to other reactors, both fission and fusion types. Moreover, the potential energy output per reactor weight and the absence of harmful radiation makes the DDH reactor an ideal candidate for space power. The logic is summarized by which the WQP requires the above conditions that make the prediction of DDH possible. The details of the DDH reaction will be presented along with the specifics of why the DDH reactor may be made to cause two deuterium nuclei to preferentially fuse to a helium nucleus. The presentation will also indicate the calculations needed to predict the reactor temperature as a function of fuel loading, reactor size, and desired output and will include the progress achieved to date

  6. Contaminación difusa originada por la actividad agrícola de riego, a la escala de la cuenca hidrográfica

    OpenAIRE

    Duarte, António Francisco Canatário

    2006-01-01

    Tese de Doutoramento apresentada à Escuela Técnica Superior de Ingenieros Agrónomos y Montes da Universidad de Córdoba. La creciente preocupación por los problemas ambientales originados por la actividad agrícola, particularmente la contaminación del agua, motiva a repensar la gestión de los sistemas y a definir códigos de buenas practicas agrícolas. Además de la importancia de la monitorización y control de los medios acuáticos que reciben los contaminantes, los modelos de simula...

  7. Relaciones de largo plazo entre el sector agrícola y el no agrícola: un estudio de cointegración para la economía peruana

    Directory of Open Access Journals (Sweden)

    Javier Escobal

    1993-06-01

    Full Text Available La evidencia internacional indica que existe cointegración en el largo plazo entre el producto agrícola y el producto no-agrícola para una serie de países. Este artículo intenta probar la validez de tal afirmación para el caso peruano, empleando para ello series anuales para estas variables desde principios de siglo. La contrastación empírica que se lleva a cabo sugiere la existencia de un vector de cointegración desde 1917 hasta 1959 aproximadamente. A partir de esta fecha la relación de cointegración cambia radicalmente mostrando a un sector agrícola que, en vez de liderar el proceso de crecimiento, se ajusta frente a la evolución de los demás sectores económicos. Esta dinámica es explicable si se toma en cuenta que, durante buena parte de la primera mitad de este siglo, el Perú siguió un modelo primario exportador, tanto de productos agrícolas (algodón y azúcar, principalmente como de minerales. Dicho modelo generó una relación estable de largo plazo entre el sector agrícola y el resto de la economía. Sin embargo, a principios de la década del cincuenta se empiezan a gestar las bases de un modelo sustitutivo de importaciones, radicalizado hacia principios de la década del sesenta y que entra en crisis a mediados de los setenta. Dicho cambio estructural implicó, en términos del modelo aquí planteado, que la relación de cointegración que primó a partir de la década del cuarenta obligara al sector agrícola y minero a ajustarse a la evolución de los sectores industrial y terciario.

  8. The high temperature reactor - an interim balance of development and operation

    International Nuclear Information System (INIS)

    The high temperature reactor is the modern version of the gas cooled reactor. The interim balance presented in this report therefore refers to all gas cooled types of reactor, i.e. Magnox, AGR, and HTR. The period covered by the balance begins 28 years ago, when the British gas cooled reactor of Calder Hall went critical for the firt time. The experience accumulated with the German experimental HTR plant, the Juelich AVR reactor, has been extremely satisfactory, both with respect to the operating behaviour and to safety. The HTR fuel elements have a high safety margin against excessive operating temperatures. Although the dominating role played by the light water reactor line has so far prevented the commercial application of high temperature reactors, developments in recent years seem to indicate new market chances for the high temperature reactor line. In this connection, special importance attaches to the prototype THTR-300, which is about to be commissioned, and to the HTR-100 and HTR-500 conceptual design drafts and the modular reactor. As the design data of the THTR-300 and the HTR-500 are partly identical, the latter plant is characterized by foreseeable preparation and construction times; in addition, the licensability of the HTR-500 has already been confirmed. A medium sized reactor like this could be the link between electricity generation and the generation of process heat and space heat. (orig.)

  9. NEUTRONIC REACTOR

    Science.gov (United States)

    Anderson, H.L.

    1960-09-20

    A nuclear reactor is described comprising fissionable material dispersed in graphite blocks, helium filling the voids of the blocks and the spaces therebetween, and means other than the helium in thermal conductive contact with the graphite for removing heat.

  10. 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.

  11. Nuclear reactors

    International Nuclear Information System (INIS)

    This draft chart contains graphical symbols from which the type of (nuclear) reactor can be seen. They will serve as illustrations for graphical sketches. Important features of the individual reactor types are marked out graphically. The user can combine these symbols to characterize a specific reactor type. The basic graphical symbol is a square with a point in the centre. Functional groups can be depicted for closer specification. If two functional groups are not clearly separated, this is symbolized by a dotted line or a channel. Supply and discharge lines for coolant, moderator and fuel are specified in accordance with DIN 2481 and can be further specified by additional symbols if necessary. The examples in the paper show several different reactor types. (orig./AK)

  12. The Choice of thermal reactor systems. A report by the National Nuclear Corporation Limited

    International Nuclear Information System (INIS)

    The report to the Secretary of State in Great Britain by the National Nuclear Corporation following their assessment of the three thermal reactor systems, the AGR, PWR and SGHWR type reactors, which was performed in order to assist in the decision on the choice of thermal reactors for the U.K., is in three parts. Part I is an assessment of the three systems. It comprises: a description of the general method of assessment; a commentary in which are summarised discussions on the most important issues influencing reactor choice, i.e. safety, component failure, operational characteristics, development programme, construction programme; implications for the U.K. industry; costs; and reference design of each system. Part II consists of related questions and answers accompanied by commentaries on public acceptability and views from industry. Part III contains some conclusions including an analysis on the implications of the choices open and a summary of the main features of the assessment. (U.K.)

  13. Multifunctional reactors

    OpenAIRE

    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 emphasis in research in the last decade. A survey is given of modern developments and the first successful applications on a large scale. It is explained why their application in many instances is ...

  14. NUCLEAR REACTOR

    Science.gov (United States)

    Anderson, C.R.

    1962-07-24

    A fluidized bed nuclear reactor and a method of operating such a reactor are described. In the design means are provided for flowing a liquid moderator upwardly through the center of a bed of pellets of a nentron-fissionable material at such a rate as to obtain particulate fluidization while constraining the lower pontion of the bed into a conical shape. A smooth circulation of particles rising in the center and falling at the outside of the bed is thereby established. (AEC)

  15. Nuclear reactor

    International Nuclear Information System (INIS)

    In order to reduce neutron embrittlement of the pressue vessel of an LWR, blanked off elements are fitted at the edge of the reactor core, with the same dimensions as the fuel elements. They are parallel to each other, and to the edge of the reactor taking the place of fuel rods, and are plates of neutron-absorbing material (stainless steel, boron steel, borated Al). (HP)

  16. Breeder reactors

    International Nuclear Information System (INIS)

    The reasons for the development of fast reactors are briefly reviewed (a propitious neutron balance oriented towards a maximum uranium burnup) and its special requirements (cooling, fissile material density and reprocessing) discussed. The three stages in the French program of fast reactor development are outlined with Rapsodie at Cadarache, Phenix at Marcoule, and Super Phenix at Creys-Malville. The more specific features of the program of research and development are emphasized: kinetics and the core, the fuel and the components

  17. Project WAGR: The UK demonstration project for power reactor decommissioning - removing the core and looking to completion

    Energy Technology Data Exchange (ETDEWEB)

    Benest, T. G. [United Kingdom Atomic Energy Authority, Headquarters, London (United Kingdom)

    2003-07-01

    The United Kingdom Atomic Energy Authority (UKAEA) has built and operated a wide range of nuclear facilities since the late 1940's. UKAEA's present mission is to restore the environment of these facilities in a safe and environmentally responsible manner. This restoration includes the decommissioning of a number of redundant research and power reactors, one of which is the Windscale Advanced Gas-cooled Reactor (WAGR). Following shut down, UKAEA decided to continue the prototype function of the reactor into the decommissioning phase to develop dismantling techniques and establish waste routes. The reactor core and pressure vessel are now being dismantled in a programme of 10 campaigns, seven of which have been completed since 1998. It is anticipated that the current programme will be completed by summer 2005. This paper outlines the history of the reactor, the operation of the waste-processing route, the installed dismantling equipment and the successful completion of the first seven campaigns. This earlier work has been described in a number of publications and conferences, so this paper concentrates on recent work to select and develop cutting equipment to dismantle the core support structures and the pressure vessel. The decommissioning of the Windscale Advance Gas-cooled reactor is being undertaken to demonstrate that a power reactor can be decommissioned shortly after shutdown. The removal of the core and pressure vessel has been broken down into a series of 10 campaigns associated with particular core components. The first 7 campaigns have been successfully completed and the 8., is expected to commence in September 2003 17 months earlier than planned. Dismantling methodologies and tools have been developed specifically for each of these campaigns. Full-scale mock-ups have been used to test the tools, train the operators and assess the duration of operations. However, despite successful trials, operational experience has shown that some of these tools

  18. Programa doctorado en mecanización agrícola un nuevo paso en el desarrollo científico de la ingeniería agrícola

    OpenAIRE

    Ciro E. Iglesias Coronel

    2006-01-01

    En el presente trabajo se brinda una panorámica del Programa Doctoral en Mecanización Agrícola, el cual se encuentra en estado de desarrollo en la actualidad, con el objetivo de darlo a conocer y recoger sugerencias para su mejora antes de su presentación a la Comisión Nacional de Grado Científico

  19. A "reforma agrária assistida pelo mercado" do Banco Mundial na Colômbia e no Brasil (1994-2002

    Directory of Open Access Journals (Sweden)

    João Márcio Mendes Pereira

    2015-01-01

    Full Text Available RESUMOO artigo analisa a implantação da "reforma agrária assistida pelo mercado" (RAAM do Banco Mundial na Colômbia e no Brasil. Mostra que a RAAM foi concebida e implementada como um modelo contrário às reformas agrárias redistributivas, baseadas na desapropriação de terras pelo Estado. Também analisa os resultados da RAAM nos dois países, argumentando que a sua função principal não foi econômica, mas sim política, ao ajustar a política agrária à agenda neoliberal e servir como instrumento para esvaziar a luta popular pela democratização da estrutura agrária em sociedades altamente desiguais.

  20. Use of oxygen dosing to prevent flow accelerated corrosion in British Energy's Advanced Gas-Cooled Reactors

    International Nuclear Information System (INIS)

    Flow accelerated corrosion (FAC) was recognized as major threat to the carbon steel feed and economizer tubing of the once-through boilers of the UK's Advanced Gas-cooled Reactors (AGRs) following the observation of FAC damage of the boiler inlet orifice assemblies at two plants in 1977, and subsequent review of the likelihood of further damage elsewhere within the boilers of all AGRs. In most cases, replacement of susceptible tubing was not feasible; due to the inaccessibility of the boiler components within the reactor concrete pressure vessel. Preventing further FAC damage within the boilers therefore had to rely largely on changes to the boiler feedwater chemistry. Following extensive research programs carried out in the late 1970s and early 1980s two main feedwater chemistry regimes were adopted to suppress FAC in different AGRs. The four units found to be at greatest risk of FAC damage adopted an oxygen dosed All Volatile Treatment (AVT) regime during commissioning, while four other units retained the original deoxygenated ammonia dosed AVT regime, but with an increased feedwater pH. The deoxygenated ammonia dosed chemistry regime was also adopted in four AGR units subsequently built, which used 1%Cr0.5%Mo feed and economizer tubing in their once-through boilers. The oxygen dosed AVT chemistry regime adopted in four units having helical once-through boilers has proved highly effective in preventing FAC, with no evidence of damage after around 150,000 hours of operation. However, FAC damage was eventually found in some of the other units operating with a deoxygenated feedwater chemistry regime, in spite of having adopted an elevated feedwater pH. These units have now successfully converted to an oxygen dosed AVT feedwater chemistry regime to prevent further FAC damage, with the result that all 14 AGR reactors now operate with variants of the original oxygen dosed feedwater chemistry regime developed during the 1980s. The paper outlines the development of

  1. Aspectos constitucionais do direito agrário emenda constitucional N° 10/64

    Directory of Open Access Journals (Sweden)

    José Carlos Vieira

    1988-07-01

    Full Text Available This paper, presents a brief history of the constitutional work applied to property rights in Brazil, mainly to those regarding land property. lt also shows the development of agrarian rights as an independent branch of the juridical prescription up to its effective recognition. It slightly shows the important role of the social function of property in constitutional texts as to support governmental actions aiming at an agrarian reform, and any other tendency to alter the rural profile of the country. This work is aimed to show that, despite a set of laws related to the agrarian reality of this country, the facts and data make it clear that nothing has been done about it up to today. The research Our constitutional texts shows that some advances towards the effectiveness of the social function of property principles have been made; nevertheless, the constitution to be promulgated by the year 1988, surprisingly takes a step backwards as to this chapter for it decreases the scope that it had in former constitutions and even in the original ones by authoritarian governments.O presente trabalho contém um resumo histórico do tratamento constitucional reservado ao direito de propriedade no Brasil, especialmente à propriedade da terra, bem assim a evolução do direito agrário como ramo autônomo do ordenamento jurídico, até o seu efetivo reconhecimento como tal. Registra, mesmo que rapidamente, a importância que teve a adotação do princípio da "função social da propriedade" nos textos constitucionais, de forma a respaldar ações governamentais objetivando a realização da reforma agrária e outras medidas tendentes a alterar o perfil rural do país. O trabalho procura mostrar, também, que, malgrado dispor o pais de um rol de leis capazes de dar suporte a propostas destinadas a promover uma efetiva mudança na realidade agrária, os fatos demonstram claramente que isto não ocorreu até hoje. A pesquisa nos textos constitucionais mostra

  2. Valoración físico-química y fitotóxica de las aguas residuales depuradas/regeneradas destinadas al riego agrícola

    Directory of Open Access Journals (Sweden)

    J.A. Pérez Donato

    2015-01-01

    Full Text Available La aplicación más extendida de la reutilización de aguas residuales domésticas depuradas/regeneradas es el riego agrícol a. Las normativas comunes sobre calidad de aguas regeneradas para reutilización contemplan paráme tros físico-químicos y biológico s para minimizar riesgos sanitarios, pero pocas veces tienen en c uenta parámetros fitotóxicos que puede n ser limitantes para aplicacio nes agrícolas. Los parámetros físico-químicos y fitotóxicos cambian al avanzar en el grado de depuración/regeneración de las aguas residuales, por lo que resulta d e interés conocer que etapa de la instalación proporciona el agua a decuada para el riego. Este tr abajo presenta un estudio de correlaci ón de fitotoxicidad con parámet ros físico-químicos en agua de muestras tomadas al final de cada un a de las etapas de tratamiento conve ncional de aguas residuales domésticas, que incluye reactor b iológico de lodos activados y tratamiento terciario con filtración de arena, cloración, filtr ación en cartucho y desalinización por electrodiálisis reversible.En cad a muestra se midió: demanda química de oxígeno, pH, conductividad , carbono orgánico, fósforo total, proteínas solubles, y los ione s de Na, K, Ca, Mg, B, F y Cl. Los criter ios de fitotoxicidad se evaluar on mediante el biomarcador Lactuca sativa. Los resultados mostraron reducciones importantes de los pa rámetros físico-químicos en el proceso de electrodiálisis, mien tras que los efectos de fitotox icidad mostraron reducciones en los pro cesos anteriores a la etapa fin al de electrodiálisis. Se concluye que l os parámetros físico-químicos , conjuntamente con el marcador biológico, constituyen aspectos d e interés práctico que relaciona e l tipo de tratamiento con la ca lidad físico-química y la fitotoxicida d del agua depurada/regenerada obtenida y su idoneidad para aplicaciones de riego agrícola.

  3. Comparative analysis of agr groups and virulence genes among subclinical and clinical mastitis Staphylococcus aureus isolates from sheep flocks of the Northeast of Brazil

    OpenAIRE

    de Almeida, Lara M.; de Almeida, Mayra Zilta P.R.B.; Carla L. Mendonça; Mamizuka, Elsa M.

    2013-01-01

    Staphylococcus aureus is one of the most frequent mastitis causative agents in small ruminants. The expression of most virulence genes of S. aureus is controlled by an accessory gene regulator (agr) locus. This study aimed to ascertain the prevalence of the different agr groups and to evaluate the occurrence of encoding genes for cytotoxin, adhesins and toxins with superantigen activity in S. aureus isolates from milk of ewes with clinical and subclinical mastitis in sheep flocks raised for m...

  4. Agrégation d'informations et alternative au krigeage en environnement aléatoire

    OpenAIRE

    Ribereau, Pierre; Rullière, Didier

    2011-01-01

    Nous définissons une notion d'information d'une variable aléatoire, qui permet en particulier de modéliser les erreurs d'estimation. Nous bâtissons un opérateur d'agrégation d'informations, qui reste cohérent avec la réduction des erreurs d'estimation lors de la réitération d'observations d'une même variable aléatoire. Nous évoquons alors les problèmes liés à l'usage du krigeage en environnement bruité, et proposons l'usage de l'opérateur d'agrégation comme alternative à la construction de su...

  5. “O Montado Multifuncional e a Integração na Politica Agrícola Comum”

    OpenAIRE

    Pinto-Correia, Teresa

    2011-01-01

    Resumo do Seminário “As diferentes funcionalidades dos montados nas políticas europeias - Caso da Política Agrícola Comum (PAC)” : Os montados são sistemas agro-silvo-pastoris equilibrados e sustentáveis, que favorecem a conservação dos recursos naturais. Estes sistemas desempenham importantes funções ecológicas, económicas e paisagísticas nas regiões em que estão inseridos, por permitirem conciliar a exploração agrícola, pecuária e cinegética com a preservação de um ecossistema de el...

  6. La prensa agrícola del porfiriato como Fuente para la historia económica. (Ensayo de Fuentes

    Directory of Open Access Journals (Sweden)

    Ma. Cecilia Zuleta

    1999-01-01

    Full Text Available Al llegar al poder el presidente de MCxico Porfirio DSaz, la &te política del país consideró que el principal problema de MCxico era el atraso económico, por lo que era indispensable impulsar.el "desarrollo económico", cuya actividad primordial, era la agricultura comercial. Por tanto, comenzó a producirse entre los sectores intelectuales, políticos y de negocios una revalorización de la importancia de la actividad agrícola y con ello, el surgimiento de publicaciones especializadas en asuntos agrícolas que son, en la actualidad, una fuente importante para reconstruir la historia econ6- mica del periodo.

  7. The sealing and testing of high integrity containers for the long term storage of AGR spent fuel

    International Nuclear Information System (INIS)

    The CEGB are designing and developing a dry storage facility for spent AGR fuel elements. The Store would be a large central facility capable of receiving fuel from any AGR Station or Sellafield and would act as a buffer in the overall spent fuel management strategy. The storage period could be long term, up to 100 years, and the store itself must be modular in construction to allow an indeterminate quantity of fuel to be stored economically and with minimum operating costs. Natural convection cooling is preferred to remove decay heat from the fuel and the technique involves sealing of fuel in containers which are placed in concrete vaults with a stack induced once-through cooling system. The remote sealing and testing of the containers prior to storage is the main topic dealt with below. (author)

  8. Research reactors - an overview

    Energy Technology Data Exchange (ETDEWEB)

    West, C.D.

    1997-03-01

    A broad overview of different types of research and type reactors is provided in this paper. Reactor designs and operating conditions are briefly described for four reactors. The reactor types described include swimming pool reactors, the High Flux Isotope Reactor, the Mark I TRIGA reactor, and the Advanced Neutron Source reactor. Emphasis in the descriptions is placed on safety-related features of the reactors. 7 refs., 7 figs., 2 tabs.

  9. AGR-1 Fuel Compact 6-3-2 Post-Irradiation Examination Results

    Energy Technology Data Exchange (ETDEWEB)

    Paul demkowicz; jason Harp; Scott Ploger

    2012-12-01

    Destructive post-irradiation examination was performed on fuel Compact 6-3-2, which was irradiated in the AGR-1 experiment to a final compact average burnup of 11.3% FIMA and a time-average, volume-average temperature of 1070°C. The analysis of this compact was focused on characterizing the extent of fission product release from the particles and examining particles to determine the condition of the kernels and coating layers. The work included deconsolidation of the compact and leach-burn-leach analysis, visual inspection and gamma counting of individual particles, measurement of fuel burnup by several methods, metallurgical preparation of selected particles, and examination of particle cross-sections with optical microscopy. A single particle with a defective SiC layer was identified during deconsolidation-leach-burn-leach analysis, which is in agreement with previous measurements showing elevated cesium in the Capsule 6 graphite fuel holder associated with this fuel compact. The fraction of the compact europium inventory released from the particles and retained in the matrix was relatively high (approximately 6E-3), indicating release from intact particle coatings. The Ag-110m inventory in individual particles exhibited a very broad distribution, with some particles retaining =80% of the predicted inventory and others retaining less than 25%. The average degree of Ag-110m retention in 60 gamma counted particles was approximately 50%. This elevated silver release is in agreement with analysis of silver on the Capsule 6 components, which indicated an average release of 38% of the Capsule 6 inventory from the fuel compacts. In spite of the relatively high degree of silver release from the particles, virtually none of the Ag-110m released was found in the compact matrix, and presumably migrated out of the compact and was deposited on the irradiation capsule components. Release of all other fission products from the particles appears to be less than a single

  10. Materials and boiler rig testing to support chemical cleaning of once-through AGR boilers

    Energy Technology Data Exchange (ETDEWEB)

    Tice, D.R.; Platts, N.; Raffel, A.S. [Serco Assurance (United Kingdom); Rudge, A. [British Energy Generation Ltd. (United Kingdom)

    2002-07-01

    An extensive programme of work has been carried out to evaluate two candidate inhibited cleaning solutions for possible implementation on plant, which would be the first chemical clean of an AGR boiler. The two candidate cleaning solutions considered were a Stannine-inhibited citric acid/formic acid mixture (GOM106) and inhibited hydrofluoric acid. Citric acid-based cleaning processes are widely used within the UK Power Industry. The GOM106 solution, comprising a mixture of 3% citric acid, 0.5% formic acid and 0.05% Stannine LTP inhibitor, buffered with ammonia to pH 3.5, was developed specifically for the AGR boilers during the 1970's. Although a considerable amount of materials testing work was carried out by British Energy's predecessor companies to produce a recommended cleaning procedure there were some remaining concerns with the use of GOM106, from these earlier studies, for example, an increased risk of pitting attack associated with the removal of thick 9Cr oxide deposits and a risk of unacceptable damage in critical locations such as the upper transition joints and other weld locations. Hence, additional testing was still required to validate the solution for use on plant. Inhibited hydrofluoric acid (HFA) was also evaluated as an alternative reagent to GOM106. HFA has been used extensively for cleaning mild and low'alloy steel boiler tubes in fossil-fired plant in the UK and elsewhere in Europe and is known to remove oxide quickly. Waste treatment is also easier than for the GOM106 process and some protection against damage to the boiler tube materials is provided by complexing of fluoride with ferric ion. Validation of the potential reagents and inhibitors was achieved by assessing the rate and effectiveness of oxide removal from specimens of helical boiler tubing and welds, together with establishing the extent of any metal loss or localised damage. The initial materials testing resulted in the inhibited ammoniated citric / formic acid

  11. Materials and boiler rig testing to support chemical cleaning of once-through AGR boilers

    International Nuclear Information System (INIS)

    An extensive programme of work has been carried out to evaluate two candidate inhibited cleaning solutions for possible implementation on plant, which would be the first chemical clean of an AGR boiler. The two candidate cleaning solutions considered were a Stannine-inhibited citric acid/formic acid mixture (GOM106) and inhibited hydrofluoric acid. Citric acid-based cleaning processes are widely used within the UK Power Industry. The GOM106 solution, comprising a mixture of 3% citric acid, 0.5% formic acid and 0.05% Stannine LTP inhibitor, buffered with ammonia to pH 3.5, was developed specifically for the AGR boilers during the 1970's. Although a considerable amount of materials testing work was carried out by British Energy's predecessor companies to produce a recommended cleaning procedure there were some remaining concerns with the use of GOM106, from these earlier studies, for example, an increased risk of pitting attack associated with the removal of thick 9Cr oxide deposits and a risk of unacceptable damage in critical locations such as the upper transition joints and other weld locations. Hence, additional testing was still required to validate the solution for use on plant. Inhibited hydrofluoric acid (HFA) was also evaluated as an alternative reagent to GOM106. HFA has been used extensively for cleaning mild and low'alloy steel boiler tubes in fossil-fired plant in the UK and elsewhere in Europe and is known to remove oxide quickly. Waste treatment is also easier than for the GOM106 process and some protection against damage to the boiler tube materials is provided by complexing of fluoride with ferric ion. Validation of the potential reagents and inhibitors was achieved by assessing the rate and effectiveness of oxide removal from specimens of helical boiler tubing and welds, together with establishing the extent of any metal loss or localised damage. The initial materials testing resulted in the inhibited ammoniated citric / formic acid reagent being

  12. Storage of thermal reactor fuels – Implications for the back end of the fuel cycle in the UK

    OpenAIRE

    Hambley David

    2016-01-01

    Fuel from UK's Advanced Gas-Cooled Reactors (AGRs) is being reprocessed, however reprocessing will cease in 2018 and the strategy for fuel that has not been reprocessed is for it to be placed into wet storage until it can be consigned to a geological disposal facility in around 2080. Although reprocessing of LWR fuel has been undertaken in the UK, and this option is not precluded for current and future LWRs, all utilities planning to operate LWRs are intending to use At-Reactor storage pendin...

  13. A Review of the UK Fast Reactor Programme: March 1980

    International Nuclear Information System (INIS)

    Towards the end of 1979 the Government announced a new programme of thermal reactor stations to be built over ten years (totalling 15GW), in addition to the two AGR stations at Torness and Heysham 'B' which had been approved by the previous Government. The first station of the new programme will be based on a Westinghouse PWR, subject to safety clearance and the outcome of a public inquiry, and it is envisaged that the remaining stations of the programme would be split between PWRs and AGRs. The AEA Chairman wrote formally to the Secretary of State for Energy in December 1979, putting forward on behalf of the Electricity Supply Authorities, NNC, BNFL and the AEA a recommended strategy for building the Commercial Demonstration Fast Reactor (CDFR), subject to normal licensing procedure and to public inquiry, so as to ensure that the key options for introducing commercial fast reactors, when required, should remain open. A Government statement is expected during the next few months. Meanwhile the level of effort on fast reactor research and development in the UK has been maintained, the fast reactor remaining the largest of the UKAEA's reactor development projects with expenditure totalling somewhat over £80M per annum. The main feature of the UK fast reactor programme has continued to be the operation of PFR (Sections 2 and 7) which is yielding a wealth of experience and of information relevant to the design of commercial fast reactors. Bum-up of standard driver fuel has reached 6-7% by heavy atoms, while specially enriched lead fuel pins have reached 11 % without failure. An extensive programme of work in the reactor and its associated steam plant was completed in March 1980 and the reactor then started its fifth power run. The fuel reprocessing plant at DNE is being commissioned and has reprocessed some of the spent fuel remaining from the DFR. It will start soon on reprocessing fuel discharged from the PFR. During the year improvements to the design of the future

  14. Ensino agrícola e influência norte-americana no Brasil (1945-1961)

    OpenAIRE

    Sonia Regina de Mendonça

    2010-01-01

    O artigo trata das redefinições sofridas pelo Ensino Agrícola no Brasil, a partir da conjuntura marcada pelo fim da II Guerra Mundial/Guerra Fria, quando inúmeros acordos de "cooperação técnica" seriam firmados entre os governos brasileiro e estadunidense, objetivando "recuperar" seu novo público-alvo: o trabalhador rural adulto e analfabeto.

  15. La Mola d'Agres (Alacant): aproximació a la indústria lítica

    OpenAIRE

    Pardo Gordó, Salvador; Peña Sánchez, José Luis; Grau Almero, Elena

    2009-01-01

    Desde su descubrimiento, las excavaciones sistemáticas han colocado la Mola d"Agres (Alicante) como yacimiento referencia en el estudio de la Edad del Bronce en tierras valencianas. La finalidad del presente trabajo es realizar una aproximación a la industria lítica tallada a partir de los materiales recuperados en las últimas campañas (2000-2007), así como valorar este conjunto dentro del contexto de la Edad del Bronce.

  16. Three-component U-Pu-Th fuel for plutonium irradiation in heavy water reactors

    Directory of Open Access Journals (Sweden)

    Peel Ross

    2016-01-01

    Full Text Available This paper discusses concepts for three-component fuel bundles containing plutonium, uranium and thorium for use in pressurised heavy water reactors, and cases for and against implementation of such a nuclear energy system in the United Kingdom. Heavy water reactors are used extensively in Canada, and are deploying within India and China, whilst the UK is considering the use of heavy water reactors to manage its plutonium inventory of 140 tonnes. The UK heavy water reactor proposal uses a mixed oxide (MOX fuel of plutonium in depleted uranium, within the enhanced CANDU-6 (EC-6 reactor. This work proposes an alternative heterogeneous fuel concept based on the same reactor and CANFLEX fuel bundle, with eight large-diameter fuel elements loaded with natural thorium oxide and 35 small-diameter fuel elements loaded with a MOX of plutonium and reprocessed uranium stocks from UK MAGNOX and AGR reactors. Indicative neutronic calculations suggest that such a fuel would be neutronically feasible. A similar MOX may alternatively be fabricated from reprocessed <5% enriched light water reactor fuel, such as the fuel of the AREVA EPR reactor, to consume newly produced plutonium from reprocessing, similar to the DUPIC (direct use of PWR fuel in CANDU process.

  17. Analysis of Gln223Agr Polymorphism of Leptin Receptor Gene in Type II Diabetic Mellitus Subjects among Malaysians

    Directory of Open Access Journals (Sweden)

    Chong Pei Pei

    2013-09-01

    Full Text Available Leptin is known as the adipose peptide hormone. It plays an important role in the regulation of body fat and inhibits food intake by its action. Moreover, it is believed that leptin level deductions might be the cause of obesity and may play an important role in the development of Type 2 Diabetes Mellitus (T2DM, as well as in cardiovascular diseases (CVD. The Leptin Receptor (LEPR gene and its polymorphisms have not been extensively studied in relation to the T2DM and its complications in various populations. In this study, we have determined the association of Gln223Agr loci of LEPR gene in three ethnic groups of Malaysia, namely: Malays, Chinese and Indians. A total of 284 T2DM subjects and 281 healthy individuals were recruited based on International Diabetes Federation (IDF criteria. Genomic DNA was extracted from the buccal specimens of the subjects. The commercial polymerase chain reaction (PCR method was carried out by proper restriction enzyme MSP I to both amplify and digest the Gln223Agr polymorphism. The p-value among the three studied races was 0.057, 0.011 and 0.095, respectively. The values such as age, WHR, FPG, HbA1C, LDL, HDL, Chol and Family History were significantly different among the subjects with Gln223Agr polymorphism of LEPR (p < 0.05.

  18. La industria de maquinaria agrícola en Argentina frente a la estructura sectorial del mercado internacional

    Directory of Open Access Journals (Sweden)

    Federico Langard

    2011-01-01

    Full Text Available En el marco de una continua reestructuración de las empresas trasnacionales productoras de maquinaria agrícola a nivel mundial, se observa una, significativa tendencia a la concentración de las mismas y a la oligopolización de la oferta mundial, situación que sin lugar a dudas impacta en nuestro país. El trabajo analiza la dinámica del comercio mundial de maquinaria agrícola, vinculada al desempeño del sector en Argentina. Para ello, se examina el comportamiento de las firmas nacionales y extranjeras [radicadas y no radicadas en el país] a partir de su inserción internacional. Para mejorar el nivel de las observaciones, el amplio espectro del sector de maquinaria agrícola es dividido en diferentes subsectores según producto. Este diseño de investigación pone en evidencia las estrategias seguidas por el entramado de empresas locales y multinacionales, en el territorio local y regional, y se observan, de acuerdo a ello, variadas ventajas en los diferentes subsectores

  19. Reactor utilization

    International Nuclear Information System (INIS)

    In 1962, the RA reactor was operated almost three times more than in 1961, producing total of 25 555 MWh. Diagram containing comparative data about reactor operation for 1960, 1961, and 1962, percent of fuel used and U-235 burnup shows increase in reactor operation. Number of samples irradiated was 659, number of experiments done was 16. mean powered level was 5.93 MW. Fuel was added into the core twice during the reporting year. In fact the core was increased from 56 to 68 fuel channels and later to 84 fuel channels. Fuel was added to the core when the reactivity worth decreased to the minimum operation level due to burnup. In addition to this 5 central fuel channels were exchanged with fresh fuel in february for the purpose of irradiation in the VISA-2 channel

  20. Reactor Neutrinos

    CERN Document Server

    Lasserre, T; Lasserre, Thierry; Sobel, Henry 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 neutrino oscillation physics in the last years. It is now widely accepted that a new middle baseline disappearance reactor neutrino experiment with multiple detectors could provide a clean measurement of the last undetermined neutrino mixing angle theta13. We conclude by opening on possible use of neutrinos for Society: NonProliferation of Nuclear materials and Geophysics.

  1. Status of the Combined Third and Fourth NGNP Fuel Irradiations In the Advanced Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    S. Blaine Grover; David A. Petti; Michael E. Davenport

    2013-07-01

    The United States Department of Energy’s Next Generation Nuclear Plant (NGNP) Advanced Gas Reactor (AGR) Fuel Development and Qualification Program is irradiating up to seven low enriched uranium (LEU) tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States. The experiments will be irradiated over the next several years to demonstrate and qualify new TRISO coated particle fuel for use in high temperature gas reactors. The goals of the experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing. The experiments, which will each consist of several independent capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control of each capsule. The sweep gas will also have on-line fission product monitoring on its effluent to track performance of the fuel in each individual capsule during irradiation. The first experiment (designated AGR-1) started irradiation in December 2006 and was completed in November 2009. The second experiment (AGR-2) started irradiation in June 2010 and is currently scheduled to be completed in September 2013. The third and fourth experiments have been combined into a single experiment designated (AGR-3/4), which started its irradiation in December 2011 and is currently scheduled to be completed in April 2014. Since the purpose of this combined experiment is to provide data on fission product migration and retention in the NGNP reactor, the design of this experiment is

  2. Nuclear reactors

    International Nuclear Information System (INIS)

    A nuclear reactor has a large prompt negative temperature coefficient of reactivity. A reactor core assembly of a plurality of fluid-tight fuel elements is located within a water-filled tank. Each fuel element contains a solid homogeneous mixture of 50-79 w/o zirconium hydride, 20-50 w/o uranium and 0.5-1.5 W erbium. The uranium is not more than 20 percent enriched, and the ratio of hydrogen atoms to zirconium atoms is between 1.5:1 and 7:1. The core has a long lifetime, E.G., at least about 1200 days

  3. Nuclear reactors

    International Nuclear Information System (INIS)

    In a liquid cooled nuclear reactor, the combination is described for a single-walled vessel containing liquid coolant in which the reactor core is submerged, and a containment structure, primarily of material for shielding against radioactivity, surrounding at least the liquid-containing part of the vessel with clearance therebetween and having that surface thereof which faces the vessel make compatible with the liquid, thereby providing a leak jacket for the vessel. The structure is preferably a metal-lined concrete vault, and cooling means are provided for protecting the concrete against reaching a temperature at which damage would occur. (U.S.)

  4. Preliminary results of post-irradiation examination of the AGR-1 TRISO fuel compacts

    Energy Technology Data Exchange (ETDEWEB)

    Paul Demkowicz; John Hunn; Robert Morris; Jason Harp; Philip Winston; Charles Baldwin; Fred Montgomery; Scott Ploger; Isabella van Rooyen

    2012-10-01

    Five irradiated fuel compacts from the AGR-1 experiment have been examined in detail in order to assess in-pile fission product release behavior. Compacts were electrolytically deconsolidated and analyzed using the leach-burn-leach technique to measure fission product inventory in the compact matrix and identify any particles with a defective SiC layer. Loose particles were then gamma counted to measure the fission product inventory. One particle with a defective SiC layer was found in the five compacts examined. The fractional release of Ag 110m from the particles was significant. The total fraction of silver released from all the particles within a compact ranged from 0-0.63 and individual particles within a single compact often exhibited a very wide range of silver release. The average fractional release of Eu-154 from all particles in a compact was 2.4×10-4—1.3×10-2, which is indicative of release through intact coatings. The fractional Cs-134 inventory in the compact matrix was <2×10-5 when all coatings remained intact, indicating good cesium retention. Approximately 1% of the palladium inventory was found in the compact matrix for two of the compacts, indicating significant release through intact coatings.

  5. Lucienville's Agriculture Corp. Ltda. Cooperativa Agrícola Lucienville Ltda.

    Directory of Open Access Journals (Sweden)

    Patricia Boari

    2008-01-01

    Full Text Available Since the evolution of agriculture corporativism and through its memoirs and balance books the present study analyzes the development of Lucienville's Agriculture Corp. Ltda. during the historic peronism. On this stage the institution got a particular incidence on diverse economic activities of national agro (seed accumulation, its industrialization and commercialization, at the same time it strengthened its role as center of social services to the associates.A partir de la evolución del cooperativismo agrario argentino y a través de sus memorias y balances el presente estudio analiza el desenvolvimiento de la Cooperativa Agrícola Lucienville Ltda. durante el peronismo histórico. En esta etapa la institución adquiere particular incidencia en las diversas actividades económicas del agro regional (acopio de semillas, su industrialización y comercialización, al tiempo que refuerza su rol como centro de servicios sociales para los asociados.

  6. Management of UKAEA graphite liabilities

    International Nuclear Information System (INIS)

    The UK Atomic Energy Authority (UKAEA) is responsible for managing its liabilities for redundant research reactors and other active facilities concerned with the development of the UK nuclear technology programme since 1947. These liabilities include irradiated graphite from a variety of different sources including low irradiation temperature reactor graphite (the Windscale Piles 1 and 2, British Experimental Pile O, Graphite Low-energy Experimental Pile at Harwell and the Material Testing Reactors at Harwell and Dounreay), advanced gas-cooled reactor graphite (from the Windscale Advanced Gas-cooled Reactor (WAGR)) and graphite from fast reactor systems (neutron shield graphite from the Dounreay Prototype Fast Reactor and Dounreay Fast Reactor). The decommissioning and dismantling of these facilities will give rise to over 6000t of graphite requiring disposal. The first graphite will be retrieved from the dismantling of Windscale pile 1 and the Windscale AGR during the next five years. UKAEA has undertaken extensive studies to consider the best practicable options for disposing of these graphite liabilities in a manner that is safe while minimizing the associated costs and technical risks. These options include (but are not limited to): disposal as low-level waste (LLW), incineration, or encapsulation and disposal as intermediate-level waste (ILW). There are a number of technical issues associated with each of these proposed disposal options; these include Wigner energy, radionuclide inventory determination, encapsulation of graphite dust, galvanic coupling interactions enhancing the corrosion of mild steel, and public acceptability. UKAEA is currently developing packaging concepts and designing packaging plants for processing these graphite wastes in consultation with other holders of graphite wastes throughout Europe. 'Letters of comfort' have been sought from both the LLW and the ILW disposal organizations to support the development of these waste disposal

  7. Air sampling system for evaluating the thyroid dose commitment due to fission products released from reactor containment. Final report

    International Nuclear Information System (INIS)

    Accidental releases of radioactivity from fission reactors will consist of active vapors and aerosols. Composition of the released plume or cloud will depend on the energy of release and fission product volatility. In accidents at Windscale and SL-1, 131I was the predominant isotope present in both the initial cloud and later release. Thus an air sampling system was developed for efficient radioiodine collection. The air sampling, readout, and dose assessment system was developed to be used in the environment after loss of containment accidents. The system can detect less than 1 rem dose commitments to thyroids of 5 year old children for immersion times of 10 hours or less. The air mover can be operated on either 110V ac power or 12V dc power available from vehicles with cigar lighter sockets. An inorganic silver loaded silica gel adsorber was developed for high mehyl iodine, HOI, and elemental iodine efficiency and low noble gas efficiency. A peal away high efficiency particulate filter permits the gaseous and particulate sample fractions to be evaluated separately. Predicted particulate iodine is combined with the adsorbed component to account for the total radioiodine in a given sample

  8. Nuclear reactor

    International Nuclear Information System (INIS)

    In an improved reactor core for a high conversion BWR reactor, Pu-breeding type BWR type reactor, Pu-breeding type BWR type rector, FEBR type reactor, etc., two types of fuel assemblies are loaded such that fuel assemblies using a channel box of a smaller irradiation deformation ratio are loaded in a high conversion region, while other fuel assemblies are loaded in a burner region. This enables to suppress the irradiation deformation within an allowable limit in the high conversion region where the fast neutron flux is high and the load weight from the inside of the channel box due to the pressure loss is large. At the same time, the irradiation deformation can be restricted within an allowable limit without deteriorating the neutron economy in the burner region in which fast neutron flux is low and the load weight from the inside of the channel box is small since a channel box with smaller neutron absorption cross section or reduced wall thickness is charged. As a result, it is possible to prevent structural deformations such as swelling of the channel box, bending of the entire assemblies, bending of fuel rods, etc. (K.M.)

  9. Role of the Agr-like quorum-sensing system in regulating toxin production by Clostridium perfringens type B strains CN1793 and CN1795.

    Science.gov (United States)

    Chen, Jianming; McClane, Bruce A

    2012-09-01

    Clostridium perfringens type B causes enteritis and enterotoxemia in domestic animals. By definition, these bacteria must produce alpha toxin (CPA), beta toxin (CPB) and epsilon toxin (ETX) although most type B strains also produce perfringolysin O (PFO) and beta2 toxin (CPB2). A recently identified Agr-like quorum-sensing (QS) system in C. perfringens controls all toxin production by surveyed type A, C, and D strains, but whether this QS is involved in regulating toxin production by type B strains has not been explored. Therefore, the current study introduced agrB null mutations into type B strains CN1795 and CN1793. Both type B agrB null mutants exhibited reduced levels of CPB, PFO, and CPA in their culture supernatants, and this effect was reversible by complementation. The reduced presence of CPB in culture supernatant involved decreased cpb transcription. In contrast, the agrB null mutants of both type B strains retained wild-type production levels of ETX and CPB2. In a Caco-2 cell model of enteritis, culture supernatants of the type B agrB null mutants were less cytotoxic than supernatants of their wild-type parents. However, in an MDCK cell in vitro model for enterotoxemic effects, supernatants from the agrB null mutants or wild-type parents were equally cytotoxic after trypsin activation. Coupling these and previous results, it is now evident that strain-dependent variations exist in Agr-like QS system regulation of C. perfringens toxin production. The cell culture results further support a role for trypsin in determining which toxins contribute to disease involving type B strains. PMID:22689820

  10. Steam generator materials constraints in UK design gas-cooled reactors

    International Nuclear Information System (INIS)

    A widely reported problem with Magnox-type reactors was the oxidation of carbon steel components in gas circuits and steam generators. The effects of temperature, pressure, gas composition and steel composition on oxidation kinetics have been determined, thus allowing the probabilities of failure of critical components to be predicted for a given set of operating conditions. This risk analysis, coupled with regular inspection of reactor and boiler internals, has allowed continued operation of all U.K. Magnox plant. The Advanced Gas Cooled Reactor (AGR) is a direct development of the Magnox design. The first four AGRs commenced operation in 1976, at Hinkley Point 'B' and at Hunterston 'B'. All known materials problems with the steam generators have been diagnosed and solved by the development of appropriate operational strategies, together with minor plant modifications. Materials constraints no longer impose any restrictions to full load performance from the steam generators throughout the predicted life of the plant. Problems discussed in detail are: 1. oxidation of the 9 Cr - 1 Mo superheater. 2. Stress corrosion of the austenitic superheater. 3. Creep of the transition joints between the 9 Cr - 1 Mo and austenitic sections. With the 9 Cr - 1 Mo oxidation maximum temperature restriction virtually removed and creep constraints properly quantified, boiler operation in now favourably placed. Stress corrosion research has allowed the risk of tube failure to be related to time, temperature, stress and chemistry. As a result, the rigorous 'no wetting' policy has been relaxed for the normally high quality AGR feedwater, and the superheat margin has been reduced to 23 deg. C. This has increased the size of the operating window and reduced the number of expensive, and potentially harmful, plant trips. (author)

  11. Analysis of the horizontal flow in the advanced gas-cooled reactor

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Y. [Department of Mechanical Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom); He, S., E-mail: s.he@sheffield.ac.uk [Department of Mechanical Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom); Ganesan, P. [Department of Mechanical Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Gotts, J. [EDF Energy, Barnwood, Gloucester GL4 3RS (United Kingdom)

    2014-06-01

    Highlights: • CFD is used to assess the effect of horizontal flows in AGRs. • The horizontal flows can reduce the graphite brick temperature significantly. • Such effects are not taken into consideration in current engineering calculations. • There might be flow instabilities when the fuel channel flow is very low but horizontal flows reduce its possibility. - Abstract: The purpose of the paper is to report a computational investigation of horizontal flows in the UK advanced-gas-cooled reactor (AGR) by using computational fluid dynamics with ANSYS FLUENT. The study is relevant to practical issues encountered in some AGR stations currently in operation in the UK. It is carried out using a comparative approach based on the results of two contrasting models: one simulating the full effect of the cross flow, the other simulating the simplified approach currently employed by the industry which neglects the momentum of the horizontal cross flow. The study reveals that the horizontal cross flow plays a significant role in the cooling of the moderator brick, while the axial variation of the brick geometry also significantly changes the distribution of the temperature within the brick. It is also found that under some circumstances the so-called horizontal inter-brick leakage (HIBL) flow could influence the cooling performance in the narrow gaps, resulting in a local hot spot. Furthermore, there may be flow instabilities in the flows in AGR fuel channels due to the interactions between the flow in the main arrowhead flow passages and that in some narrow passages connected to it, but the influence on the brick temperature is negligible. Horizontal cross flow has an effect of reducing such instabilities.

  12. Final Assembly and Initial Irradiation of the First Advanced Gas Reactor Fuel Development and Qualification Experiment in the Advanced Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    S. B. Grover

    2007-05-01

    The United States Department of Energy’s Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating eight separate low enriched uranium (LEU) oxycarbide (UCO) tri-isotropic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The ATR has a long history of irradiation testing in support of reactor development and the INL has been designated as the new United States Department of Energy’s lead laboratory for nuclear energy development. The ATR is one of the world’s premiere test reactors for performing long term, high flux, and/or large volume irradiation test programs. These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States. The AGR fuel experiments will be irradiated over the next ten years to demonstrate and qualify new particle fuel for use in high temperature gas reactors. The goals of the irradiation experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing.1,2 The experiments, which will each consist of six separate capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control of each capsule. The sweep gas will also have on-line fission product monitoring on its effluent to track performance of the fuel in each individual capsule during irradiation. The final design phase for the first experiment was completed in 2005, and the fabrication and assembly of the first experiment test train (designated AGR-1) as well as the support systems and fission product monitoring system that will monitor and control the experiment

  13. Final Assembly and Initial Irradiation of the First Advanced Gas Reactor Fuel Development and Qualification Experiment in the Advanced Test Reactor

    International Nuclear Information System (INIS)

    The United States Department of Energy's Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating eight separate low enriched uranium (LEU) oxycarbide (UCO) tri-isotropic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The ATR has a long history of irradiation testing in support of reactor development and the INL has been designated as the new United States Department of Energy's lead laboratory for nuclear energy development. The ATR is one of the world's premiere test reactors for performing long term, high flux, and/or large volume irradiation test programs. These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States. The AGR fuel experiments will be irradiated over the next ten years to demonstrate and qualify new particle fuel for use in high temperature gas reactors. The goals of the irradiation experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing. The experiments, which will each consist of six separate capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control of each capsule. The sweep gas will also have on-line fission product monitoring on its effluent to track performance of the fuel in each individual capsule during irradiation. The final design phase for the first experiment was completed in 2005, and the fabrication and assembly of the first experiment test train (designated AGR-1) as well as the support systems and fission product monitoring system that will monitor and control the experiment during

  14. A History of Dosimetry for the Advanced Gas-cooled Reactors

    Directory of Open Access Journals (Sweden)

    Shaw Simon

    2016-01-01

    Full Text Available This paper presents a summary of the methods used in the first ∼40 years of AGR neutron dosimetry and nuclear heating calculations, and the influence of the earlier Magnox reactor dosimetry programme. While the current state-of-the-art Monte Carlo methods are extremely powerful they still require very careful consideration of the quality of the input data, nuclear data validation and variance reduction techniques; in particular, this paper examines the difficulties in assuring the adequate convergence of calculations when Monte Carlo acceleration is applied in the presence of significant streaming paths through attenuating or scattering media.

  15. Reactor container

    International Nuclear Information System (INIS)

    A reactor container has a suppression chamber partitioned by concrete side walls, a reactor pedestal and a diaphragm floor. A plurality of partitioning walls are disposed in circumferential direction each at an interval inside the suppression chamber, so that independent chambers in a state being divided into plurality are formed inside the suppression chamber. The partition walls are formed from the bottom portion of the suppression chamber up to the diaphragm floor to isolate pool water in a divided state. Operation platforms are formed above the suppression chamber and connected to an access port. Upon conducting maintenance, inspection or repairing, a pump is disposed in the independent chamber to transfer pool water therein to one or a plurality of other independent chambers to make it vacant. (I.N.)

  16. Reactor building

    International Nuclear Information System (INIS)

    The present invention concerns a structure of ABWR-type reactor buildings, which can increase the capacity of a spent fuel storage area at a low cost and improved earthquake proofness. In the reactor building, the floor of a spent fuel pool is made flat, and a depth of the pool water satisfying requirement for shielding is ensured. In addition, a depth of pool water is also maintained for a equipment provisionally storing pool for storing spent fuels, and a capacity for a spent fuel storage area is increased by utilizing surplus space of the equipment provisionally storing pool. Since the flattened floor of the spent fuel pool is flushed with the floor of the equipment provisionally storing pool, transfer of horizontal loads applied to the building upon occurrence of earthquakes is made smooth, to improve earthquake proofness of the building. (T.M.)

  17. Nuclear reactors

    International Nuclear Information System (INIS)

    Disclosed is a nuclear reactor cooled by a freezable liquid has a vessel for containing said liquid and comprising a structure shaped as a container, and cooling means in the region of the surface of said structure for effecting freezing of said liquid coolant at and for a finite distance from said surface for providing a layer of frozen coolant on and supported by said surface for containing said liquid coolant. In a specific example, where the reactor is sodium-cooled, the said structure is a metal-lined concrete vault, cooling is effected by closed cooling loops containing NaK, the loops extending over the lined surface of the concrete vault with outward and reverse pipe runs of each loop separated by thermal insulation, and air is flowed through cooling pipes embedded in the concrete behind the metal lining. 7 claims, 3 figures

  18. NEUTRONIC REACTORS

    Science.gov (United States)

    Anderson, J.B.

    1960-01-01

    A reactor is described which comprises a tank, a plurality of coaxial steel sleeves in the tank, a mass of water in the tank, and wire grids in abutting relationship within a plurality of elongated parallel channels within the steel sleeves, the wire being provided with a plurality of bends in the same plane forming adjacent parallel sections between bends, and the sections of adjacent grids being normally disposed relative to each other.

  19. Nuclear reactor

    International Nuclear Information System (INIS)

    The liquid metal (sodium) cooled fast breeder reactor has got fuel subassemblies which are bundled and enclosed by a common can. In order to reduce bending of the sides of the can because of the load caused by the coolant pressure the can has got a dodecagon-shaped crosssection. The surfaces of the can may be of equal width. One out of two surfaces may also be convex towards the center. (RW)

  20. Nuclear reactor

    International Nuclear Information System (INIS)

    A detector having high sensitivity to fast neutrons and having low sensitivity to thermal neutrons is disposed for reducing influences of neutron detector signals on detection values of neutron fluxes when the upper end of control rod pass in the vicinity of the neutron flux detector. Namely, the change of the neutron fluxes is greater in the thermal neutron energy region while it is smaller in the fast neutron energy region. This is because the neutron absorbing cross section of B-10 used as neutron absorbers of control rods is greater in the thermal neutron region and it is smaller in the fast neutron region. As a result, increase of the neutron detection signals along with the local neutron flux change can be reduced, and detection signals corresponding to the reactor power can be obtained. Even when gang withdrawal of operating a plurality of control rods at the same time is performed, the reactor operation cycle can be measured accurately, thereby enabling to shorten the reactor startup time. (N.H.)

  1. The DOE Advanced Gas Reactor Fuel Development and Qualification Program

    International Nuclear Information System (INIS)

    The high outlet temperatures and high thermal-energy conversion efficiency of modular High Temperature Gas-cooled Reactors (HTGRs) enable an efficient and cost effective integration of the reactor system with non-electricity generation applications, such as process heat and/or hydrogen production, for the many petrochemical and other industrial processes that require temperatures between 300 C and 900 C. The Department of Energy (DOE) has selected the HTGR concept for the Next Generation Nuclear Plant (NGNP) Project as a transformative application of nuclear energy that will demonstrate emissions-free nuclear-assisted electricity, process heat, and hydrogen production, thereby reducing greenhouse-gas emissions and enhancing energy security. The objective of the DOE Advanced Gas Reactor (AGR) Fuel Development and Qualification program is to qualify tristructural isotropic (TRISO)-coated particle fuel for use in HTGRs. The Advanced Gas Reactor Fuel Development and Qualification Program consists of five elements: fuel manufacture, fuel and materials irradiations, post-irradiation examination (PIE) and safety testing, fuel performance modeling, and fission-product transport and source term evaluation. An underlying theme for the fuel development work is the need to develop a more complete, fundamental understanding of the relationship between the fuel fabrication process and key fuel properties, the irradiation and accident safety performance of the fuel, and the release and transport of fission products in the NGNP primary coolant system. An overview of the program and recent progress is presented.

  2. Evidence that the Agr-like quorum sensing system regulates the toxin production, cytotoxicity and pathogenicity of Clostridium perfringens type C isolate CN3685.

    Science.gov (United States)

    Vidal, Jorge E; Ma, Menglin; Saputo, Julian; Garcia, Jorge; Uzal, Francisco A; McClane, Bruce A

    2012-01-01

    Clostridium perfringens possesses at least two functional quorum sensing (QS) systems, i.e. an Agr-like system and a LuxS-dependent AI-2 system. Both of those QS systems can reportedly control in vitro toxin production by C. perfringens but their importance for virulence has not been evaluated. Therefore, the current study assessed whether these QS systems might regulate the pathogenicity of CN3685, a C. perfringens type C strain. Since type C isolates cause both haemorrhagic necrotic enteritis and fatal enterotoxemias (where toxins produced in the intestines are absorbed into the circulation to target other internal organs), the ability of isogenic agrB or luxS mutants to cause necrotizing enteritis in rabbit small intestinal loops or enterotoxemic lethality in mice was evaluated. Results obtained strongly suggest that the Agr-like QS system, but not the LuxS-dependent AI-2 QS system, is required for CN3685 to cause haemorrhagic necrotizing enteritis, apparently because the Agr-like system regulates the production of beta toxin, which is essential for causing this pathology. The Agr-like system, but not the LuxS-mediated AI-2 system, was also important for CN3685 to cause fatal enterotoxemia. These results provide the first direct evidence supporting a role for any QS system in clostridial infections. PMID:22150719

  3. Existence of two groups of Staphylococcus aureus strains isolated from bovine mastitis based on biofilm formation, intracellular survival, capsular profile and agr-typing.

    Science.gov (United States)

    Bardiau, Marjorie; Caplin, Jonathan; Detilleux, Johann; Graber, Hans; Moroni, Paolo; Taminiau, Bernard; Mainil, Jacques G

    2016-03-15

    Staphylococcus (S.) aureus is recognised worldwide as an important pathogen causing contagious acute and chronic bovine mastitis. Chronic mastitis account for a significant part of all bovine cases and represent an important economic problem for dairy producers. Several properties (biofilm formation, intracellular survival, capsular expression and group agr) are thought to be associated with this chronic status. In a previous study, we found the existence of two groups of strains based on the association of these features. The aim of the present work was to confirm on a large international and non-related collection of strains the existence of these clusters and to associate them with case history records. In addition, the genomes of eight strains were sequenced to study the genomic differences between strains of each cluster. The results confirmed the existence of both groups based on capsular typing, intracellular survival and agr-typing: strains cap8-positive, belonging to agr group II, showing a low invasion rate and strains cap5-positive, belonging to agr group I, showing a high invasion rate. None of the two clusters were associated with the chronic status of the cow. When comparing the genomes of strains belonging to both clusters, the genes specific to the group "cap5-agrI" would suggest that these strains are better adapted to live in hostile environment. The existence of these two groups is highly important as they may represent two clusters that are adapted differently to the host and/or the surrounding environment. PMID:26931384

  4. Retrospectiva agroecológica a la interacción entre sistemas agrícolas tradicionales y modernos.

    Directory of Open Access Journals (Sweden)

    René Montalva

    2003-05-01

    Full Text Available En este trabajo se realiza un acercamiento desde la agroecología crítica a los orígenes y la expansión de la "agricultura moderna" y a su extensión hacia los sistemas agrícolas  tradicionales del tercer mundo. Asítambién, se analizan los efectos de esta transformación y de la adopción de las prácticas genéricas de la agricultura modema en los sistemas agrícolas familiares, principalmente campesinos e indígenas. Los antecedentes históricos recopilados ponen de manifisto que este proceso ha sido ampliamente desfavorable para los sistemas familiares, particulamente en aspectos económico -productivos, ambientales y sociales; encontrando el origen de gran parte de sus problemas actuales en la expansión de la "nueva agricultura" y en el modelo de desarrollo que hay tras ella. Con el respaldo de argumentos de tipo empírico y teóricos actuales, en este trabajo se concluye que, al igual que lo que ha ocurrido en otros lugares del planeta, la "rnodemización" de los sistemas agrícola familiares, con base tradicional, no dará solución al estado de pobreza material en la cual se encuentran campesinos e indígenas de los países del tercer mundo, sino que por el contrario producirá otros tipos de pobreza y problemas de diversa índole, muchos de ellos con efectos inciertos.

  5. Huella hídrica de productos agrícolas producidos en la sierra central y comercializados en Lima

    Directory of Open Access Journals (Sweden)

    Tito Mallma Capcha

    2015-06-01

    Full Text Available El objetivo ha sido determinar un modelo para obtener la huella hídrica de los principales productos agrícolas de la sierra central del Perú que son comercializados en los mercados de la ciudad de Lima, para ello se desarrolló un modelo conceptual que determine el requerimiento de agua de los cultivos que junto a los respectivos rendimientos han permitido establecer el contenido de agua virtual de cada producto agrícola expresado en l/kg; con este resultado y la cantidad de producto comercializado, se han determinado el agua virtual (AV transferida hacia el mercado de Lima, correspondiente a los catorce productos agrícolas considerados. Se obtuvieron valores que indican que los volúmenes de agua virtual entre los productos varían por las cantidades comercializadas y están en función de la producción que a su vez depende de factores como el clima, la demanda del consumidor y de la tecnología empleada en la producción. Así, el consumo de un kg de papa en la ciudad de Lima implica la transferencia de 300,71 litros de “agua virtual” desde la región Junín, donde se produce el producto. El producto que transfiere la mayor cantidad de agua virtual es la papa con 78 069 926,37 m3, seguido de la arveja verde con 16 889 273,96 m3, y el producto que transfiere la menor cantidad es la cebolla con 10 336,59 m3, en tanto que el volumen total de agua virtual transferida es de 165 595 592,28 m3.

  6. Informe sobre Cuestiones Agrícolas de un Viaje a California y a Méjico

    Directory of Open Access Journals (Sweden)

    Navarro Ospina Francisco

    1939-12-01

    Full Text Available La magnitud de la industria agrícola, del Estado de California, es imposible de abarcarla y apreciarla. El éxito de la industria frutera de California se debe, a demás de las condiciones excepcionales de la región, a los cuidados que se tienen con los cultivos y en gran parte a la ayuda y protección dados por el Gobierno, valiéndose del Departamento de Agricultura y de las Estaciones Experimentales, las cuales le prestan toda dase de facilidades al agricultor; no sólo en aquello que se relaciona directamente con el cultivo, control de plagas y enfermedades, sino también fomentando la creación de cooperativas y asociaciones para la venta de los frutos. Entre las industrias agrícolas de Méjico, merecen mencionarse, por su adaptabilidad en nuestro medio, la de la cabuya y la fabricación de almidones. Estas industrias han dado sorprendentes resultados en aquel país y entre nosotros seguramente se obtendrán iguales resultados si para ello se pone un conato decidido y se presta eficaz ayuda. Es hora ya, de que nuestro gobierno y en especial el Ministerio de Agricultura, tome alguna iniciativa para impulsar una industria agrícola que indudablemente puede llegar a ser de grande importancia para el país, como lo ha sido en el Brasil y en otras regiones del globo, regiones cuyas condiciones ni son mejores ni ofrecen las perspectivas de clima y situación geográfica de Colombia.

  7. Reactor core of nuclear reactor

    International Nuclear Information System (INIS)

    In a BWR type nuclear reactor, the number of first fuel assemblies (uranium) loaded in a reactor core is smaller than that of second fuel assemblies (mixed oxide), the average burnup degree upon take-out of the first fuel assemblies is reduced to less than that of the second fuel assemblies, and the number of the kinds of the fuel rods constituting the first fuel assemblies is made smaller than that of the fuel rods constituting the second fuel assemblies. As a result, the variety of the plutonium enrichment degree is reduced to make the distribution of the axial enrichment degree uniform, thereby enabling to simplify the distribution of the enrichment degree. Then the number of molding fabrication steps for MOX fuel assemblies can be reduced, thereby enabling to reduce the cost for molding and fabrication. (N.H.)

  8. Uso de plaguicidas en cultivos agrícolas como herramienta para el monitoreo de peligros en salud

    OpenAIRE

    Virya Bravo Durán; Elba de la Cruz Malavassi; Gustavo Herrera Ledezma; Fernando Ramírez Muñoz

    2013-01-01

    Costa Rica ha incrementado el uso de plaguicidas de mayor toxicidad, debido entre otras cosas al desarrollo de plagas más resistentes y la necesidad que tienen algunos productos agrícolas de exportación de mantener su posición en el mercado internacional. El ser humano al entrar en contacto con los plaguicidas puede experimentar efectos adversos en su salud desde agudos hasta crónicos que se manifiestan en diferentes grados. Para generar indicadores de peligro en salud en algunos cultivos por...

  9. Lluvia, escurrimiento y producción de sedimentos en una microcuenca agrícola del sistema de Tandilia

    OpenAIRE

    Ares, María Guadalupe

    2014-01-01

    La erosión hídrica es uno de los principales procesos de degradación que afectan a las tierras agrícolas a nivel mundial. Sus efectos tienen consecuencias en el sitio donde ocurre, al disminuir la capacidad productiva de las tierras. Al mismo tiempo ocasionan externalidades, debido a la sedimentación en canales y reservorios y a la contaminación que puede provocar. En Argentina, estadísticas del año 1990 indican que la erosión afecta 30 millones de hectáreas, y recientemente se ha establecido...

  10. Estudi econòmic de l'oli de colza com a biocarburant en explotacions agrícoles

    OpenAIRE

    Baquero Armans, Grau; Esteban Dalmau, Bernat; Puig Vidal, Rita; Riba Ruiz, Jordi-Roger; Rius Carrasco, Antoni

    2010-01-01

    Actualment els biocarburants ocupen una important àrea d’estudi, essent el biodièsel i el bioetanol els més utilitzats en el nostre territori. La major part d’aquests biocarburants són de primera generació i la seva fabricació a gran escala presenta seriosos problemes ambientals i socials a causa de la gran demanda de terres agrícoles [1-2]. Tot i això, la necessitat de reduir l’emissió de gasos d’efecte hivernacle n’incrementa la seva demanda. Actualment, és interessant pensar en implemen...

  11. Segmentación automática de texturas en imágenes agrícolas

    OpenAIRE

    Riomoros Callejo, M. Isabel

    2010-01-01

    En los últimos años, ha aparecido el concepto de Agricultura de Precisión, gracias al desarrollo de las nuevas tecnologías. Esto ha hecho que los problemas surgidos con las prácticas agrícolas tradicionales, tal es el caso de la utilización de herbicidas o el abonado generalizado, se vayan solventando conforme avanzan las investigaciones. En la Agricultura de Precisión se hace especial hincapié en las técnicas orientadas a la aplicación selectiva de tratamientos, es decir, al uso de herbic...

  12. Classificação de cores de embalagens de defensivos agrícolas utilizando Redes Bayesianas

    OpenAIRE

    Andrade, Eduardo de

    2013-01-01

    Resumo: O método empregado atualmente na classificação da cor de embalagens de defensivos agrícolas consiste na inspeção visual humana. Todavia a quantidade de embalagens recebidas mensalmente nas centrais de recolhimento e o grau de toxicidade da embalagem tornam esse trabalho exaustivo, insalubre e suscetível a falhas. O presente trabalho demonstra que através da aquisição de uma imagem digital da embalagem é possível realizar a classificação baseada na sua cor. O trabalho de classificação ...

  13. Perspectivas do uso de legislaçao na preservaçao do solo agrícola

    OpenAIRE

    Cavalet, Valdo José

    2012-01-01

    O processo de degradação dos recursos naturais e crescente em nosso planeta. Dentre os recursos naturais renováveis, o solo agrícola está perdendo a sua fertilidade num ritmo muito acelerado, sendo considerado o principal problema ambiental da atualidade. A causa mais direta da destruição do solo e o seu uso intensivo, desordenado e desprovido de um manejo adequado. Isto é resultante da prioridade dada pelos governantes a uma política que busca o crescimento econômico a qualquer custo, on...

  14. La prensa agrícola del porfiriato como Fuente para la historia económica. (Ensayo de Fuentes)

    OpenAIRE

    Ma. Cecilia Zuleta

    1999-01-01

    Al llegar al poder el presidente de MCxico Porfirio DSaz, la &te política del país consideró que el principal problema de MCxico era el atraso económico, por lo que era indispensable impulsar.el "desarrollo económico", cuya actividad primordial, era la agricultura comercial. Por tanto, comenzó a producirse entre los sectores intelectuales, políticos y de negocios una revalorización de la importancia de la actividad agrícola y con ello, el surgimiento de publicaciones especializ...

  15. Efectos del manejo agrícola sobre las aves paseriformes en el olivar mediterráneo

    OpenAIRE

    Castro Caro, Juan Carlos

    2016-01-01

    El olivar es uno de los usos predominantes de tierra en la cuenca mediterránea, donde 5 millones de hectáreas se dedican a este cultivo (la mitad de los cuales están en España), con significativas implicaciones sociales, ambientales y económicos. En las últimas décadas la intensificación agrícola ha llevado a una homogeneización y simplificación de los paisajes tierras de cultivo en toda Europa con consecuencias ambientales negativas. La contaminación del agua, la pérdida de bi...

  16. Fuentes de crecimiento del empleo en el sector agrícola del norte de México

    OpenAIRE

    José Alberto Salazar García; José Miguel Omaña Silvestre

    2001-01-01

    El desempleo de mano de obra es uno de los problemas más agudos que actualmente enfrentan las zonas rurales de México. Con la finalidad de determinar cómo el cambio en la estructura productiva del sector agrícola del norte de México ha afectado el empleo rural de la región, se calculan las fuentes de crecimiento del empleo de mano de obra de 1991 a 1998. Los resultados indican que en Baja California, Chihuahua y Sonora el cambio en la estructura productiva fue positivo al empleo, mientras que...

  17. Aprendizaje cooperativo interdisciplinario en el tema de gestión de residuos agrícolas y ganaderos

    OpenAIRE

    Suárez, María Dolores; Sáez, María Isabel; Cañero, Rafael; Casas, José Jesús; Guil-Guerrero, José Luis; Martínez, Tomás Francisco; Alarcón López, Francisco Javier; Rincón-Cervera, Miguel Ángel; Venegas-Venegas, Elena

    2012-01-01

    Este grupo docente pretende implementar metodologías innovadoras docentes y técnicas de evaluación desde un enfoque pluridisciplinar en las titulaciones relacionadas con la Agronomía y el Medio Ambiente de la Universidad de Almería, con un nexo común, la buena gestión de los residuos procedentes de las explotaciones agrícolas y ganaderas, aumentando su reutilización y minimizando su incidencia ambiental. Para ello se realizarán trabajos cooperativos dónde participarán de forma coordinada a...

  18. Design and performance of the helically coiled boilers of two AGR power stations in the United Kingdom

    International Nuclear Information System (INIS)

    The Hartlepool and Heysham-I AGR stations have been commissioned and operating since 1983. The main features, of the design of the helical once-through boilers raising the steam for power generation, are outlined. The modifications to the feed inlet flow ferrules, necessary to improve the boiler performance and optimize the power output, have been described. Comparisons between the thermal and hydrodynamic performance of the boilers before and following these alterations are given. The improvements in the computer code predictions of the plant performance have also been presented. (author)

  19. Transformaciones agrícolas en la Región Pampeana Argentina y el despoblamiento en las comunidades rurales

    OpenAIRE

    Stratta Fernández, Ricardo Rubén; Ríos Carmenado, Ignacio de los

    2010-01-01

    El objetivo de este trabajo, es realizar una caracterización del proceso histórico del desarrollo agrícola en la Región Pampeana, examinando al mismo tiempo, 1os rasgos principales del proceso de despoblamiento rural. La caracterización se realiza definiendo cuatro etapas históricas, de acuerdo a cuatro criterios que marcan las particularidades de cada una de ellas: 1) las condiciones económicas externas; 2) el marco político y económico interno; 3) el comportamiento de los factores de la pro...

  20. Capacidad supresiva contra Rosellinia necatrix de suelos agrícolas enmendados con cáscara de almendra

    OpenAIRE

    Vida, Carmen; Cazorla, Francisco M.; Bonilla, Nuria; de Vicente, Antonio

    2014-01-01

    El aguacate es uno de los principales cultivos subtropicales del sur de España y la podredumbre blanca de la raíz, causada por el hongo fitopatógeno Rosellinia necatrix, uno de sus problemas más graves. Desde hace tiempo, se ha utilizado la aplicación de enmiendas orgánicas como estrategia para mejorar la supresividad de los suelos agrícolas frente a determinadas enfermedades de plantas. En este trabajo, tratamos de evaluar la capacidad supresiva de los suelos enmendados con cá...

  1. Xi congreso nacional de ingeniería agrícola y áreas afines- conferencias magistrales

    OpenAIRE

    Facultad Nacional de Agronomía, Universidad Nacional de Colombia

    2013-01-01

    En este artículo podemos encontrar las conferencias magistrales de XI Congreso Nacional de Ingeniería Agrícola y Áreas Afines en el que se pueden encontrar las siguientes: Automatización en la industria azucarera de Brasil. Este texto presenta una historia resumida del desarrollo de la industria azucarera en Brasil, con énfasis en la producción de alcohol. Se muestra también, la composición de la matriz energética brasilera y la contribución de la energía proveniente de la biomasa, en especia...

  2. Cooperativa-escola nas Escolas Técnicas Agrícolas Cooperative-school at the Agricultural Technical Schools

    OpenAIRE

    Marques, P V; H.G. Love

    1993-01-01

    A dificuldade de gerenciar recursos e proporcionar melhores condições de ensino para os estudantes são algumas das deficiência das Escolas Técnicas Agrícolas (ETAs) brasileiras, problemas parcialmente superados por algumas escolas que adotaram a chamada Cooperativa-Escola. Neste trabalho, procura-se discutir alguns aspectos filosóficos referentes às ETAs e como a Cooperativa-Escola pode ajudar a solucionar seus principais problemas educativos e administrativos; um estudo de caso utilizando-se...

  3. Los Organismos Genéticamente Modificados: Opinión de un agrónomo

    OpenAIRE

    Durand, Jean-Louis

    2006-01-01

    Los organismos genéticamente modificados (OGM) inquietan: por ello se plantea investigar desde un punto de vista racional las consecuencias de su aparición para el conjunto de la sociedad. Una aproximación crítica a la cuestión de los OGM debe situarlos en el contexto general de la producción agrícola para el desarrollo sostenible. Los OGM combinan dos transformaciones profundas: una tecnológica, otra jurídico-comercial. Si la primera merece ser analizada con prudencia, es probablemente el as...

  4. The siting of UK nuclear reactors

    International Nuclear Information System (INIS)

    Choosing a suitable site for a nuclear power station requires the consideration and balancing of several factors. Some ‘physical’ site characteristics, such as the local climate and the potential for seismic activity, will be generic to all reactors designs, while others, such as the availability of cooling water, the area of land required and geological conditions capable of sustaining the weight of the reactor and other buildings will to an extent be dependent on the particular design of reactor chosen (or alternatively the reactor design chosen may to an extent be dependent on the characteristics of an available site). However, one particularly interesting tension is a human and demographic one. On the one hand it is beneficial to place nuclear stations close to centres of population, to reduce transmission losses and other costs (including to the local environment) of transporting electricity over large distances from generator to consumer. On the other it is advantageous to place nuclear stations some distance away from such population centres in order to minimise the potential human consequences of a major release of radioactive materials in the (extremely unlikely) event of a major nuclear accident, not only in terms of direct exposure but also concerning the management of emergency planning, notably evacuation. This paper considers the emergence of policies aimed at managing this tension in the UK. In the first phase of nuclear development (roughly speaking 1945–1965) there was a highly cautious attitude, with installations being placed in remote rural locations with very low population density. The second phase (1965–1985) saw a more relaxed approach, allowing the development of AGR nuclear power stations (which with concrete pressure vessels were regarded as significantly safer) closer to population centres (in ‘semi-urban’ locations, notably at Hartlepool and Heysham). In the third phase (1985–2005) there was very little new nuclear

  5. Calibration of dimensional change in finite element models using AGR moderator brick measurements

    International Nuclear Information System (INIS)

    Physically based models, resolved using the finite element (FE) method, are often used to model changes in geometry and the associated stress fields of graphite moderator bricks within a reactor. These models require inputs that describe the loading conditions (field variables), and coded relationships describing the behaviour of material properties. Historically, behaviour on material properties have been obtained from Materials Test Reactor (MTR) experiments, however data relating to samples trepanned from operating reactors are increasingly being used to improve models. Geometry measurements from operating reactors offer the potential for improving the coded relationship for dimensional change in FE models. A non-linear mixed-effect model is presented for calibrating the parameters of FE models that are sensitive to mid-brick diameter, using channel geometry measurements obtained from inspection campaigns. The work makes use of a novel technique: the development of a Bayesian emulator, which is a surrogate for the FE model. The use of an emulator allows the influence of the inputs to the finite element model to be evaluated, and delivers a substantial reduction in the computational burden of calibration

  6. Calibration of dimensional change in finite element models using AGR moderator brick measurements

    Energy Technology Data Exchange (ETDEWEB)

    McNally, K., E-mail: kevin.mcnally@hsl.gsi.gov.uk [Health and Safety Laboratory, Harpur Hill, Buxton, Derbyshire SK17 9JN (United Kingdom); Hall, G. [NGRG, School of MACE, University of Manchester, Manchester M13 9PL (United Kingdom); Tan, E. [Health and Safety Laboratory, Harpur Hill, Buxton, Derbyshire SK17 9JN (United Kingdom); Marsden, B.J. [NGRG, School of MACE, University of Manchester, Manchester M13 9PL (United Kingdom); Warren, N. [Health and Safety Laboratory, Harpur Hill, Buxton, Derbyshire SK17 9JN (United Kingdom)

    2014-08-01

    Physically based models, resolved using the finite element (FE) method, are often used to model changes in geometry and the associated stress fields of graphite moderator bricks within a reactor. These models require inputs that describe the loading conditions (field variables), and coded relationships describing the behaviour of material properties. Historically, behaviour on material properties have been obtained from Materials Test Reactor (MTR) experiments, however data relating to samples trepanned from operating reactors are increasingly being used to improve models. Geometry measurements from operating reactors offer the potential for improving the coded relationship for dimensional change in FE models. A non-linear mixed-effect model is presented for calibrating the parameters of FE models that are sensitive to mid-brick diameter, using channel geometry measurements obtained from inspection campaigns. The work makes use of a novel technique: the development of a Bayesian emulator, which is a surrogate for the FE model. The use of an emulator allows the influence of the inputs to the finite element model to be evaluated, and delivers a substantial reduction in the computational burden of calibration.

  7. Types of Nuclear Reactors

    International Nuclear Information System (INIS)

    The presentation is based on the following areas: Types of Nuclear Reactors, coolant, moderator, neutron spectrum, fuel type, pressurized water reactor (PWR), boiling water reactor (BWR) reactor pressurized heavy water (PHWR), gas-cooled reactor, RBMK , Nuclear Electricity Generation,Challenges in Nuclear Technology Deployment,EPR, APR1400, A P 1000, A PWR, ATMEA 1, VVER-1000, A PWR, VVER 1200, Boiling Water Reactor, A BWR, A BWR -II, ESBUR, Ke ren, AREVA, Heavy Water Reactor, Candu 6, Acr-1000, HWR, Bw, Iris, CAREM NuCcale, Smart, KLT-HOS, Westinghouse small modular Reactor, Gas Cooled Reactors, PBMR.

  8. Nuclear reactor

    International Nuclear Information System (INIS)

    A nuclear reactor is described in which the core components, including fuel-rod assemblies, control-rod assemblies, fertile rod-assemblies, and removable shielding assemblies, are supported by a plurality of separate inlet modular units. These units are referred to as inlet module units to distinguish them from the modules of the upper internals of the reactor. The modular units are supported, each removable independently of the others, in liners in the supporting structure for the lower internals of the reactor. The core assemblies are removably supported in integral receptacles or sockets of the modular units. The liners, units, sockets and assemblies have inlet openings for entry of the fluid. The modular units are each removably mounted in the liners with fluid seals interposed between the opening in the liner and inlet module into which the fluid enters in the upper and lower portion of the liner. Each assembly is similarly mounted in a corresponding receptacle with fluid seals interposed between the openings where the fluid enters in the lower portion of the receptacle or fitting closely in these regions. As fluid flows along each core assembly a pressure drop is produced along the fluid so that the fluid which emerges from each core assembly is at a lower pressure than the fluid which enters the core assembly. However because of the seals interposed in the mountings of the units and assemblies the pressures above and below the units and assemblies are balanced and the units are held in the liners and the assemblies are held in the receptacles by their weights as they have a higher specific gravity than the fluid. The low-pressure spaces between each module and its liner and between each core assembly and its module is vented to the low-pressure regions of the vessel to assure that fluid which leaks through the seals does not accumulate and destroy the hydraulic balance

  9. Solo agrícola e agricultura em espaço urbano: dinâmicas. O exemplo de Évora

    OpenAIRE

    Freire, Maria; Ramos, Isabel

    2014-01-01

    O objetivo do artigo é melhorar o entendimento sobre o significado da componente agrícola em espaço urbano para as sociedades e perspetivar estratégias no sentido de promover o património solo agrícola e a permanência e sustentabilidade do uso agrícola em espaço urbano. A metodologia de trabalho seguida compreende a análise da dinâmica de evolução urbana, associada à presença da agricultura em espaço urbano em Évora, numa perspetiva que inclui o seu significado nos domínios históricos, soc...

  10. Agrégation de critères interactifs au moyen de l'intégrale de Choquet discrète

    OpenAIRE

    Marichal, Jean-Luc

    1999-01-01

    L'opérateur le plus souvent utilisé pour agréger des critères dans les problèmes d'aide multicritère à la décision est la moyenne arithmétique pondérée. Cependant, dans de nombreux problèmes pratiques, les critères interagissent, ce qui nécessite l'emploi d'un agrégateur plus général. Nous montrons que, sous des hypothèses assez naturelles, l'intégrale de Choquet discrète est un opérateur d'agrégation approprié qui généralise la moyenne arithmétique pondérée par la prise en compte de l'intera...

  11. First principles investigations on the mechanical and vibrational properties for the selected B2-AgRE (RE=Sc, Y, La, Ce) intermetallics

    Energy Technology Data Exchange (ETDEWEB)

    Çoban, C., E-mail: cansucoban@yahoo.com [Balıkesir University, Department of Physics, Çağış Campus, 10145, Balıkesir (Turkey); Çiftci, Y.Ö., E-mail: yasemin@gazi.edu.tr [Gazi University, Department of Physics, Teknikokullar, 06500, Ankara (Turkey); Çolakoglu, K. [Gazi University, Department of Physics, Teknikokullar, 06500, Ankara (Turkey)

    2015-01-15

    We calculated the lattice constants, bulk modulus and its pressure derivative, elastic constants of B2- based AgRE (RE=Sc, Y, La, Ce) compounds using first principles calculations based on density functional theory (DFT). The elastic properties such as Zener anisotropy factor, Young's modulus, Poisson's ratio, and shear modulus were obtained using the calculated elastic constants. To understand bonding properties, the total charge density and Mulliken charge population were calculated. The phonon dispersion curves and one-phonon density of states were obtained and presented. Also, we presented the temperature variations of various thermodynamic properties such as entropy and heat capacity for the AgRE (RE=Sc, Y, La, Ce). We compared our results for AgRE (RE=Sc, Y, La, Ce) intermetallics with the previous data. Our calculated results for these compounds agree well with the previous theoretical calculations and the experiments.

  12. Entre a propriedade e o salário. Memórias dos trabalhos agrícolas em Alpiarça (anos 50/80

    Directory of Open Access Journals (Sweden)

    Dilce Freire

    2006-09-01

    Full Text Available Até aos anos 60 do século XX, Portugal foi um país essencialmente agrícola e rural. O rápido êxodo rural facilitou o abandono ou a transformação da agricultura. Apresenta-se aqui uma reflexão sobre os actuais processos de rememoração das práticas agrícolas numa vila do Ribatejo (Portugal e sobre a amnésia social verificada relativamente ao passado agrícola, que decorre das transformações ocorridas e dos valores sociais e culturais associados à reconstrução da identidade da vila de Alpiarça.

  13. Nuclear research reactors

    International Nuclear Information System (INIS)

    It's presented data about nuclear research reactors in the world, retrieved from the Sien (Nuclear and Energetic Information System) data bank. The information are organized in table forms as follows: research reactors by countries; research reactors by type; research reactors by fuel and research reactors by purpose. (E.G.)

  14. Nuclear reactor physics course for reactor operators

    International Nuclear Information System (INIS)

    The education and training of nuclear reactor operators is important to guarantee the safe operation of present and future nuclear reactors. Therefore, a course on basic 'Nuclear reactor physics' in the initial and continuous training of reactor operators has proven to be indispensable. In most countries, such training also results from the direct request from the safety authorities to assure the high level of competence of the staff in nuclear reactors. The aim of the basic course on 'Nuclear Reactor Physics for reactor operators' is to provide the reactor operators with a basic understanding of the main concepts relevant to nuclear reactors. Seen the education level of the participants, mathematical derivations are simplified and reduced to a minimum, but not completely eliminated

  15. Regadíos agrícolas, territorio y desarrollo rural

    Directory of Open Access Journals (Sweden)

    Moyano Estrada, Eduardo

    2008-02-01

    Full Text Available This article analyses how the topics linked to water management have changed in social perception and political agenda in Spain. From a hydraulic and agricultural-oriented logic it has shifted toward other more integral and multifunctional one, where the Ministry of Environment is the most relevant player. In such a social and political context, the new orientations of rural development policies are analysed, particularly in relation to the sustainable management of water resources in farming sector and their implications on territory. The authors propose a typology of irrigable areas in Spain, and analyse the process of implementation of the new European Regulation on Rural Development (Reg. 1690/2005. The conclusion is that this new policy could be a useful tool to promote the environmental sustainability of these areas only if there was a good coordination between agricultural and environmental departments at the regional level.En este artículo se analiza la percepción social y política de los temas relacionados con la gestión del agua en España, mostrando cómo se ha pasado de una lógica hidráulica y sectorial (agraria, canalizada a través de los ministerios de Obras Públicas y Agricultura, a otra integral y multifuncional, en la que se valoran sus implicaciones territoriales y en la que asume protagonismo el ministerio de Medio Ambiente. En ese contexto, se analizan las nuevas orientaciones de las políticas de desarrollo rural, especialmente en lo relacionado con la gestión sostenible de los recursos hídricos en la agricultura y sus efectos sobre el territorio. La diversidad del regadío agrícola en España es analizada por los autores, proponiendo una tipología de zonas regables con problemas de eficiencia, y valorando en qué medida las acciones contempladas en el nuevo Reglamento europeo de Desarrollo Rural (FEADER pueden ser un instrumento útil para avanzar en la sostenibilidad ambiental de dichas áreas. La conclusi

  16. Nuclear reactor

    International Nuclear Information System (INIS)

    Cover gas spaces for primary coolant vessel, such as a reactor container, a pump vessel and an intermediate heat exchanger vessel are in communication with each other by an inverted U-shaped pressure conduit. A transmitter and a receiver are disposed to the pressure conduit at appropriate positions. If vibration frequencies (pressure vibration) from low frequency to high frequency are generated continuously from the transmitter to the inside of the communication pipe, a resonance phenomenon (air-column resonance oscillation) is caused by the inherent frequency or the like of the communication pipe. The frequency of the air-column resonance oscillation is changed by the inner diameter and the clogged state of the pipelines. Accordingly, by detecting the change of the air-column oscillation characteristics by the receiver, the clogged state of the flow channels in the pipelines can be detected even during the reactor operation. With such procedures, steams of coolants flowing entrained by the cover gases can be prevented from condensation and coagulation at a low temperature portion of the pipelines, otherwise it would lead clogging in the pipelines. (I.N.)

  17. Análisis de la competitividad agrícola del municipio de Arauca (Arauca): corregimiento de Todos los Santos

    OpenAIRE

    Garzón Peña, Mary Ilsa

    2013-01-01

    El presente trabajo de investigación tuvo como propósito analizar la competitividad agrícola del municipio de Arauca (Arauca), específicamente en lo que respecta a los sistemas productivos de plátano y cacao ubicados en el corregimiento de Todos los Santos, toda vez que esta zona representa la única área productiva del municipio para estos dos cultivos. Dicho análisis se desarrolló basado en el comportamiento de la producción del período 2000-2010 y tomando como referencia el mercado agrícola...

  18. Actuaciones de un colector solar de aire para secado de productos agrícolas en países en vías de desarrollo

    OpenAIRE

    Esteban Biescas, Sandra

    2015-01-01

    El uso de secaderos solares para el secado de productos agrícolas es una de las tecnologías apropiadas en crecimiento en los países en vías de desarrollo. En el marco de las tecnologías apropiadas se define el presente Trabajo Fin de Grado para caracterizar el proceso de calentamiento de aire y la capacidad de secado de un secadero solar activo (de convección forzada) de tipo distribuido protegiendo así al máximo los productos agrícolas de los agentes externos. Este sistema se basa en el a...

  19. Elementos de diseño de maquinaria agrícola: informe de año sabático

    OpenAIRE

    Álvarez Mejía, Fernando

    2007-01-01

    El texto que aquí se presenta se adapta al programa de la asignatura Mecanismos que actualmente viene impartiéndose en la formación de los Ingenieros Agrícolas y servirá de guía al estudio de las máquinas agrícolas para profesiones afines al sector agropecuario. Los estudiantes deberán haber adquirido un conjunto de herramientas de ingeniería que consisten esencialmente de matemáticas, geometría, física y varias de las ciencias básicas como la resistencia de los materiales. Estas herramientas...

  20. Políticas de precios y subsidios agrícolas: impactos macroeconómico y sectorial: Perú 1985-1988.

    OpenAIRE

    Javier Escobal

    1989-01-01

    Este documento presenta y analiza las principales políticas aplicadas por el gobierno aprista para reactivar el agro peruano, evaluando su viabilidad financiera de corto y mediano plazo y sus efectos sobre el propio sector agrario y la economía en su conjunto. Describe y analiza la política de precios agrícolas, la política cambiaria y la política crediticia; evalúa los efectos de las políticas macroeconómicas descritas y de los subsidios agrícolas, en especial aquéllos que inciden sobre la i...

  1. Sostenibilitat de dos projectes de cooperació al desenvolupament agrícola a Tape Iguapegui (Argentina) i a Celica (Ecuador)

    OpenAIRE

    Bastos Pirra, Ramiro; Simón Bueno, Óscar

    2007-01-01

    Les comunitats camperoles de Tape Iguapegui (Algarrobito en castellà) i Celica agrupen respectivament a 25 i 52 famílies participants en dos projectes de desenvolupament agrícola, “Desarrollo agrícola en Algarrobito”i “Huertas familiars y granges comunitàries en Celica”. L’objectiu d’aquests projectes és millorar els sistemes de maneig agropecuari d’ambdues comunitats, basats principalment en el blat de moro de “Tumba Roza y Quema”. L’objectiu del present treball era evaluar a priori...

  2. Desarrollo de herramientas computacionales para el manejo de bases de datos ambientales. Estudio de caso ecosistema agrícola urbano en el D.F.

    OpenAIRE

    Carreón Barrios, Claudia Evelia

    2015-01-01

    El manejo eficiente de la información ambiental es un tópico de creciente interés en las actividades agrícolas, especialmente en términos del gran volumen de datos que se manejan, la complejidad de los procesos agrícolas y la demandante tarea de adquisición de información. La Ciudad de México no cuenta con bases de datos o herramientas computacionales orientadas hacia el análisis de los sistemas de agricultura urbana y que sustenten la formulación de una mejor toma de decisiones. En este cont...

  3. Los sistemas integrados de producción agrícola en el desarrollo sostenible dei norte de Minas Gerais, Brasil.

    OpenAIRE

    Cunha, Lize de Moraes Vieira da

    2010-01-01

    Los Sistemas Integrados de Producción Agrícola en el desarrollo sustentable dei Norte de Minas Gerais, Brasil” surge a partir de la ejecución de actividades de asistencia técnica y extensión rural realizadas en la Colonización Paraguaçu en la región semiárida dei estado de Minas Gerais. Registro de la trayectoria de la agricultura familiar y de la extensión rural. Com talleres, reuniones, visitas técnicas y encuestas fue posible caracterizar los sistemas agrícolas actuales, así como sus dific...

  4. Potencial de biodegradación de DDT y sus metabolitos en suelos agrícolas de Chinandega

    Directory of Open Access Journals (Sweden)

    Carlos E. Noguera Solís

    2008-04-01

    Full Text Available LA PRESENTE INVESTIGACIÓN EVALUÓ EL POTENCIAL DE BIODEGRADACIÓN DEL 1,1,1-Tricloro- 2,2-bis(4-clorofeniletano (DDT y sus metabolitos en suelos agrícolas pertenecientes a fincas del municipio de El Viejo, Chinandega, a través de dos ensayos: ensayo de biodegradación ex situ y ensayo de búsqueda e identificación de microorganismos capaces de biodegradar DDT. En el primer ensayo se determinó el porcentajede biodegradación, bajo condiciones idóneas, durante un período de 100 días en diferentes lotes de suelo con diferentes aditivos (cachaza y estiércol a través de la aplicación de cepas microbianas comerciales Environoc 201®. De ello se obtuvo como resultado un porcentaje de biodegradación mayor para el lote que no presentaba aditivos orgánicos, siendo éste de 23,92%. En el ensayo de búsqueda eidentificación de bacterias se lograron aislar e identificar cepas microbianas nativas de los suelos agrícolas objeto de estudio utilizando medios de cultivo con DDT como única fuente de carbono y energía. Como resultado se lograron identificar los siguientes microorganismos: Pseudomonas sp., Streptomyces sp., Phanerochaetechrysosporium y levaduras.

  5. La sucesión "mortis causa" en la explotación agrícola familiar

    Directory of Open Access Journals (Sweden)

    José Luis De Los Mozos

    2015-01-01

    Full Text Available Llevo nada menos que cuarenta años dando vueltas al tema de la sucesión mortis causa en el Derecho agrario y más concretamente, al de la sucesión en la explotación agrícola. Esto no constituye ningún mérito, naturalmente, no es más que una mera circunstancia que acredita, cuando mucho, la firmeza de una convicción. Durante este tiempo, con mayor o menor contacto con la realidad social, he seguido y sigo fiel a mis puntos de vista originarios; no es que nada haya cambiado en todos estos años, sino que ha cambiado casi todo.Pero es que las soluciones que me parecían entonces muy dudosas, ahora me parecen inadmisibles.La evolución económica y social, ha puesto de relieve que las ideas que se utilizaban hace medio siglo en la materia, actualmente han quedado obsoletas (...Contenido: Una distinción obligada y un recuerdo inevitable. El recurso a la atribución preferente. Las condicionantes de la atribución preferente. El concepto de explotación agrícola. La reforma del derecho sucesorio como recapitulación

  6. Modernização da Agricultura em Moçambique: determinantes da renda agrícola

    Directory of Open Access Journals (Sweden)

    Carlos E. Guanziroli

    2015-03-01

    Full Text Available O objetivo deste trabalho é verificar até que ponto as tecnologias oriundas da revolução verde foram efetivamente adotadas na África Subsaariana e, nos casos em que foram adotadas, se tiveram sucesso em melhorar a renda e a produtividade da agricultura. Para este fim, o trabalho faz primeiramente um breve resumo do estado das artes da revolução verde na África, mostrando quais países avançaram mais e como se correlaciona a utilização de fertilizantes químicos com os aumentos de produtividade. Faz-se também uma discussão sobre as características do processo de intensificação num caso em particular, o de Moçambique. Finalmente, com base nos microdados do Tratado de Inquérito Agrícola (TIA, se testa um modelo econométrico de MQO que visa avaliar os determinantes da renda agrícola e, em particular, do uso de fertilizantes químicos.

  7. Mecanización agrícola, empleo y migración en el norte de Tamaulipas

    Directory of Open Access Journals (Sweden)

    José Luis Contreras Valenzuela

    1986-05-01

    Full Text Available El objetivo del presente trabajo es analizar el modelo de desarrollo agrícola recientemente adoptado en los distritos de riego del norte de Tamaulipas, y los efectos sobre el empleo y la migración de la población rural. Dicho análisis se efectuará a partir de dos premisas fundamentales: una de ellas es la internacionalización del proceso productivo que se manifiesta con la presencia de una nueva división internacional del trabajo y lo que en este ensayo es llamada economía campesina, que fue la fuente primaria de la acumulación de capital de la agricultura mexicana, la cual jugará un papel importante para la acumulación de capital de la agricultura de los Estados Unidos de América, mediante la oferta de fuerza de trabajo agrícola barata, permitiendo el desarrollo de la agricultura comercial, modelo que ahora se ha volcado sobre la economía campesina condenándola a su desaparición como forma de subsistencia de la población rural, a quien expulsa de sus unidades de producción mediante el acaparamiento y el rentismo.

  8. A Review of the United Kingdom Fast Reactor Programme

    International Nuclear Information System (INIS)

    On 25 February 1988 the Secretary of State for Energy, Mr Cecil Parkinson, announced the Government's plans for privatizing the UK's Electricity Supply Industry (ESI). In order to promote competition and greater efficiency the responsibility for supplying electricity in England and Wales will, according to Government plans, be vested in twelve regional distribution companies. These companies will jointly own and control a new national grid company. The Central Electricity Generating Board (CEGB) will cease to control the national grid and will be split into two companies. Some 30% of the existing capacity will be owned by one company, all of it non-nuclear. The remaining 70% of the capacity, including all nuclear stations, will be owned by a second company. The obligation to supply electricity to the consumer will be transferred to the distribution companies who will buy electricity as economically as possible from the generating companies, from the two generating companies planned for Scotland, from new or existing private generating companies and from abroad. The Government will ensure that diversity of supply will be maintained by specifying that a proportion of electricity should come from non-fossil fuels. Nuclear power will be regulated as at present, and a series of new pressurized water reactors (PWRs) will be encouraged. Arrangements for funding future R&D for the nuclear industry have still to be announced. About 18% of all electricity generated in the UK during 1987 was from nuclear stations. This proportion is expected to rise to around 25% in 1988 as the two advanced gas-cooled reactors (AGRs) reactors at Torness and the two AGR reactors at Heysham 2 reach full power. Each reactor will supply 1280 MWe. The first PWR in the UK (Sizewell B) is under construction and should reach full power in 1995. An application has been made for consent to build a second PWR at Hinkley Point, Somerset. The national nuclear waste disposal company, NIREX, owned by the

  9. 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.

  10. 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.

  11. The Next Generation Nuclear Plant/Advanced Gas Reactor Fuel Irradiation Experiments in the Advanced Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    S. Blaine Grover

    2009-09-01

    The United States Department of Energy’s Next Generation Nuclear Plant (NGNP) Program will be irradiating eight separate low enriched uranium (LEU) tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The ATR has a long history of irradiation testing in support of reactor development and the INL has been designated as the new United States Department of Energy’s lead laboratory for nuclear energy development. The ATR is one of the world’s premiere test reactors for performing long term, high flux, and/or large volume irradiation test programs. These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States, and will be irradiated over the next ten years to demonstrate and qualify new particle fuel for use in high temperature gas reactors. The goals of the irradiation experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing. The experiments, which will each consist of at least six separate capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control of each capsule. The sweep gas will also have on-line fission product monitoring on its effluent to track performance of the fuel in each individual capsule during irradiation. The first experiment (designated AGR-1) started irradiation in December 2006, and the second experiment (AGR-2) is currently in the design phase. The design of test trains, as well as the support systems and fission product monitoring system that will monitor and control the experiment during irradiation will be discussed. In

  12. Reactor container

    International Nuclear Information System (INIS)

    Purpose: To prevent shocks exerted on a vent head due to pool-swell caused within a pressure suppression chamber (disposed in a torus configuration around the dry well) upon loss of coolant accident in BWR type reactors. Constitution: The following relationship is established between the volume V (m3) of a dry well and the ruptured opening area A (m2) at the boundary expected upon loss of coolant accident: V >= 30340 (m) x A Then, the volume of the dry well is made larger than the ruptured open area, that is, the steam flow rate of leaking coolants upon loss of coolant accident to decrease the pressure rise in the dry well at the initial state where loss of coolant accident is resulted. Accordingly, the pressure of non-compressive gases jetted out from the lower end of the downcomer to the pool water is decreased to suppress the pool-swell. (Ikeda, J.)

  13. State, Bank and Agricultural Credit in Sinaloa and Sonora: The Banco de Sinaloa and Banco Agrícola Sonorense, 1933-1976 Estado, banca y crédito agrícola en Sinaloa y Sonora: El Banco de Sinaloa y el Banco Agrícola Sonorense, 1933-1976

    Directory of Open Access Journals (Sweden)

    Gustavo Aguilar Aguilar

    2011-01-01

    Full Text Available In the Northwest of México the increase in the agricultural productivity in the years between 1940 and 1970, was due to the expansion of the farming lands, the use of improved seeds and fertilizer, mechanization, the greater availability of credit, the irrigation system and road improvement. The important intervention from the Mexican state to implement policies of investment with the support of internationally development agencies, and grant credit facilities for the development of agriculture trough the creation of official agricultural banks and the facilities to the constitution of private commercial banks. After the disarticulation of the bank in México due to the revolution, is advanced with steady steps in restructuring the banking system with the creation of a new banking law, the foundation of Banco de México and the Comision Nacional Bancaria in 1924; Banco Nacional de Credito Agricola (1926, the Banco Nacional de Credito Ejidal (1935, Banco Nacional de Comercio Exterior (1937 and the Banco Nacional Agropecuario (1965, which gave financial support to small farmers and ejidatarios (members of a cooperative. The main farmers of Sinaloa and Sonora in collaboration with the federal government through the Comision Monetaria and the Banco de México founded the Banco de Sinaloa and Banco Agricola Sonorense in 1933. Explain the impact these financial institutions had in the agricultural credit of Sinaloa and Sonora will be the central objective of this work.En el Noroeste de México el incremento en la productividad agrícola entre los años de 1940 y 1970, fue debido a la expansión de las tierras de cultivo, el uso de fertilizantes y semillas mejoradas, la mecanización, la mayor disponibilidad de créditos, a los sistemas de irrigación y el mejoramiento de las carreteras. Así como la importante intervención del Estado mexicano al implementar políticas de inversión con el apoyo de agencias internacionales de desarrollo, y otorgar

  14. Genetic algorithms and artificial neural networks for loading pattern optimisation of advanced gas-cooled reactors

    International Nuclear Information System (INIS)

    A non-generational genetic algorithm (GA) has been developed for fuel management optimisation of Advanced Gas-Cooled Reactors, which are operated by British Energy and produce around 20% of the UK's electricity requirements. An evolutionary search is coded using the genetic operators; namely selection by tournament, two-point crossover, mutation and random assessment of population for multi-cycle loading pattern (LP) optimisation. A detailed description of the chromosomes in the genetic algorithm coded is presented. Artificial Neural Networks (ANNs) have been constructed and trained to accelerate the GA-based search during the optimisation process. The whole package, called GAOPT, is linked to the reactor analysis code PANTHER, which performs fresh fuel loading, burn-up and power shaping calculations for each reactor cycle by imposing station-specific safety and operational constraints. GAOPT has been verified by performing a number of tests, which are applied to the Hinkley Point B and Hartlepool reactors. The test results giving loading pattern (LP) scenarios obtained from single and multi-cycle optimisation calculations applied to realistic reactor states of the Hartlepool and Hinkley Point B reactors are discussed. The results have shown that the GA/ANN algorithms developed can help the fuel engineer to optimise loading patterns in an efficient and more profitable way than currently available for multi-cycle refuelling of AGRs. Research leading to parallel GAs applied to LP optimisation are outlined, which can be adapted to present day LWR fuel management problems

  15. First elevated-temperature performance testing of coated particle fuel compacts from the AGR-1 irradiation experiment

    International Nuclear Information System (INIS)

    In the AGR-1 irradiation experiment, 72 coated-particle fuel compacts were taken to a peak burnup of 19.5% fissions per initial metal atom with no in-pile failures. This paper discusses the first post-irradiation test of these mixed uranium oxide/uranium carbide fuel compacts at elevated temperature to examine the fuel performance under a simulated depressurized conduction cooldown event. A compact was heated for 400 h at 1600 °C. Release of 85Kr was monitored throughout the furnace test as an indicator of coating failure, while other fission product releases from the compact were periodically measured by capturing them on exchangeable, water-cooled deposition cups. No coating failure was detected during the furnace test, and this result was verified by subsequent electrolytic deconsolidation and acid leaching of the compact, which showed that all SiC layers were still intact. However, the deposition cups recovered significant quantities of silver, europium, and strontium. Based on comparison of calculated compact inventories at the end of irradiation versus analysis of these fission products released to the deposition cups and furnace internals, the minimum estimated fractional losses from the compact during the furnace test were 1.9 × 10−2 for silver, 1.4 × 10−3 for europium, and 1.1 × 10−5 for strontium. Other post-irradiation examination of AGR-1 compacts indicates that similar fractions of europium and silver may have already been released by the intact coated particles during irradiation, and it is therefore likely that the detected fission products released from the compact in this 1600 °C furnace test were from residual fission products in the matrix. Gamma analysis of coated particles deconsolidated from the compact after the heating test revealed that silver content within each particle varied considerably; a result that is probably not related to the furnace test, because it has also been observed in other as-irradiated AGR-1 compacts. X

  16. First elevated-temperature performance testing of coated particle fuel compacts from the AGR-1 irradiation experiment

    Energy Technology Data Exchange (ETDEWEB)

    Charles A. Baldwin; John D. Hunn; Robert N. Morris; Fred C. Montgomery; Chinthaka M. Silva; Paul A. Demkowicz

    2014-05-01

    In the AGR-1 irradiation experiment, 72 coated-particle fuel compacts were taken to a peak burnup of 19.5% fissions per initial metal atom with no in-pile failures. This paper discusses the first post-irradiation test of these mixed uranium oxide/uranium carbide fuel compacts at elevated temperature to examine the fuel performance under a simulated depressurized conduction cooldown event. A compact was heated for 400 h at 1600 degrees C. Release of 85Kr was monitored throughout the furnace test as an indicator of coating failure, while other fission product releases from the compact were periodically measured by capturing them on exchangeable, water-cooled deposition cups. No coating failure was detected during the furnace test, and this result was verified by subsequent electrolytic deconsolidation and acid leaching of the compact, which showed that all SiC layers were still intact. However, the deposition cups recovered significant quantities of silver, europium, and strontium. Based on comparison of calculated compact inventories at the end of irradiation versus analysis of these fission products released to the deposition cups and furnace internals, the minimum estimated fractional losses from the compact during the furnace test were 1.9 x 10-2 for silver, 1.4 x 10-3 for europium, and 1.1 x 10-5 for strontium. Other post-irradiation examination of AGR-1 compacts indicates that similar fractions of europium and silver may have already been released by the intact coated particles during irradiation, and it is therefore likely that the detected fission products released from the compact in this 1600 degrees C furnace test were from residual fission products in the matrix. Gamma analysis of coated particles deconsolidated from the compact after the heating test revealed that silver content within each particle varied considerably; a result that is probably not related to the furnace test, because it has also been observed in other as-irradiated AGR-1 compacts. X

  17. First elevated-temperature performance testing of coated particle fuel compacts from the AGR-1 irradiation experiment

    Energy Technology Data Exchange (ETDEWEB)

    Baldwin, Charles A., E-mail: baldwinca@ornl.gov [Oak Ridge National Laboratory (ORNL), P.O. Box 2008, Oak Ridge, TN 37831-6295 (United States); Hunn, John D.; Morris, Robert N.; Montgomery, Fred C.; Silva, Chinthaka M. [Oak Ridge National Laboratory (ORNL), P.O. Box 2008, Oak Ridge, TN 37831-6295 (United States); Demkowicz, Paul A. [Idaho National Laboratory (INL), P.O. Box 1625, Idaho Falls, ID 83414 (United States)

    2014-05-01

    In the AGR-1 irradiation experiment, 72 coated-particle fuel compacts were taken to a peak burnup of 19.5% fissions per initial metal atom with no in-pile failures. This paper discusses the first post-irradiation test of these mixed uranium oxide/uranium carbide fuel compacts at elevated temperature to examine the fuel performance under a simulated depressurized conduction cooldown event. A compact was heated for 400 h at 1600 °C. Release of {sup 85}Kr was monitored throughout the furnace test as an indicator of coating failure, while other fission product releases from the compact were periodically measured by capturing them on exchangeable, water-cooled deposition cups. No coating failure was detected during the furnace test, and this result was verified by subsequent electrolytic deconsolidation and acid leaching of the compact, which showed that all SiC layers were still intact. However, the deposition cups recovered significant quantities of silver, europium, and strontium. Based on comparison of calculated compact inventories at the end of irradiation versus analysis of these fission products released to the deposition cups and furnace internals, the minimum estimated fractional losses from the compact during the furnace test were 1.9 × 10{sup −2} for silver, 1.4 × 10{sup −3} for europium, and 1.1 × 10{sup −5} for strontium. Other post-irradiation examination of AGR-1 compacts indicates that similar fractions of europium and silver may have already been released by the intact coated particles during irradiation, and it is therefore likely that the detected fission products released from the compact in this 1600 °C furnace test were from residual fission products in the matrix. Gamma analysis of coated particles deconsolidated from the compact after the heating test revealed that silver content within each particle varied considerably; a result that is probably not related to the furnace test, because it has also been observed in other as

  18. Comparative analysis of agr groups and virulence genes among subclinical and clinical mastitis Staphylococcus aureus isolates from sheep flocks of the Northeast of Brazil.

    Science.gov (United States)

    de Almeida, Lara M; de Almeida, Mayra Zilta P R B; de Mendonça, Carla L; Mamizuka, Elsa M

    2013-01-01

    Staphylococcus aureus is one of the most frequent mastitis causative agents in small ruminants. The expression of most virulence genes of S. aureus is controlled by an accessory gene regulator (agr) locus. This study aimed to ascertain the prevalence of the different agr groups and to evaluate the occurrence of encoding genes for cytotoxin, adhesins and toxins with superantigen activity in S. aureus isolates from milk of ewes with clinical and subclinical mastitis in sheep flocks raised for meat production The agr groups I and II were identified in both cases of clinical and subclinical mastitis. Neither the arg groups III and IV nor negative agr were found. The presence of cflA gene was identified in 100% of the isolates. The frequency of hla and lukE-D genes was high - 77.3 and 82.8%, respectively and all isolates from clinical mastitis presented these genes. The sec gene, either associated to tst gene or not, was identified only in isolates from subclinical mastitis. None of the following genes were identified: bbp, ebpS, cna, fnbB, icaA, icaD, bap, hlg, lukM-lukF-PV and se-a-b-d-e. PMID:24294245

  19. Eficiência energética de um trator agrícola utilizando duas configurações de tomada de potência

    Directory of Open Access Journals (Sweden)

    Ulisses Giacomini Frantz

    2014-07-01

    Full Text Available A tomada de potência (TDP de um trator agrícola tem por principal finalidade transmitir a potência gerada no motor, para acionamento de órgãos ativos das máquinas agrícolas. Tendo em vista a necessidade de se aumentar a eficiência energética na agricultura, alguns fabricantes disponibilizam para os agricultores uma configuração de TDP que proporciona o acionamento dessas máquinas a um regime de rotação menor do motor do trator. Assim, a rotação da TDP é mantida podendo-se obter uma redução do consumo de combustível. Este trabalho objetivou quantificar o consumo de combustível de um trator agrícola, operando com duas configurações de TDP (normal e econômica em duas áreas agrícolas de relevo distinto. Como resultado, evidencia-se que, com a utilização da TDP econômica, tanto o consumo horário quanto o consumo operacional de combustível, em ambas as áreas trabalhadas, foi menor quando comparado à TDP normal.

  20. Treball pràctic d'edafologia i química agrícola. Curs 2008-2009

    OpenAIRE

    Universitat de Barcelona. Facultat de Farmàcia

    2008-01-01

    Pla docent de l'assignatura Treball pràctic d'edafologia i química agrícola de l'Ensenyament de Ciència i Tecnologia dels Aliments. Curs acadèmic 2008-2009. Departament Productes Naturals, Biologia Vegetal i Edafologia.

  1. Treball pràctic d'edafologia i química agrícola. Curs 2005-2006

    OpenAIRE

    Universitat de Barcelona. Facultat de Farmàcia

    2005-01-01

    Pla docent de l'assignatura Treball pràctic d'edafologia i química agrícola de l'Ensenyament de Ciència i Tecnologia dels Aliments. Curs acadèmic 2005-2006. Departament de Productes Naturals, Biologia Vegetal i Edafologia.

  2. Survey of research reactors

    International Nuclear Information System (INIS)

    A survey of reasearch reactors based on the IAEA Nuclear Research Reactor Data Base (RRDB) was done. This database includes information on 273 operating research reactors ranging in power from zero to several hundred MW. From these 273 operating research reactors 205 reactors have a power level below 5 MW, the remaining 68 reactors range from 5 MW up to several 100 MW thermal power. The major reactor types with common design are: Siemens Unterrichtsreaktors, 1.2 Argonaut reactors, Slowpoke reactors, the miniature neutron source reactors, TRIGA reactors, material testing reactors and high flux reactors. Technical data such as: power, fuel material, fuel type, enrichment, maximum neutron flux density and experimental facilities for each reactor type as well as a description of their utilization in physics and chemistry, medicine and biology, academic research and teaching, training purposes (students and physicists, operating personnel), industrial application (neutron radiography, silicon neutron transmutation doping facilities) are provided. The geographically distribution of these reactors is also shown. As conclusions the author discussed the advantages (low capital cost, low operating cost, low burn up, simple to operate, safe, less restrictive containment and sitting requirements, versatility) and disadvantages (lower sensitivity for NAA, limited radioisotope production, limited use of neutron beams, limited access to the core, licensing) of low power research reactors. 24 figs., refs. 15, Tab. 1 (nevyjel)

  3. Department of reactor technology

    International Nuclear Information System (INIS)

    The activities of the Department of Reactor Technology at Risoe during 1979 are described. The work is presented in five chapters: Reactor Engineering, Reactor Physics and Dynamics, Heat Transfer and Hydraulics, The DR 1 Reactor, and Non-Nuclear Activities. A list of the staff and of publications is included. (author)

  4. RB reactor noise analysis

    International Nuclear Information System (INIS)

    Statistical fluctuations of reactivity represent reactor noise. Analysis of reactor noise enables determining a series of reactor kinetic parameters. Fluctuations of power was measured by ionization chamber placed next to the tank of the RB reactor. The signal was digitized by an analog-digital converter. After calculation of the mean power, 3000 data obtained by sampling were analysed

  5. A Review of the United Kingdom Fast Reactor Programme, March 1987

    International Nuclear Information System (INIS)

    Nuclear power produced about 20% of the electricity supply in the United Kingdom in 1986, mostly from gas-cooled reactors, i.e. the 10 AGRs currently in operation and the 26 older MAGNOX reactors. Plans to increase the nuclear component of generating capacity by building the first PWR in the UK, Sizewell 'B', were strongly endorsed in the report by Sir Frank Layfield published on 26 January 1987. This resulted from the Public Inquiry into building Sizewell 'B', which was held between 11 January 1983 and 7 March 1985, the longest Public Inquiry ever held in the UK. The government gave the go-ahead for the building of Sizewell 'B' on 12 March 1987

  6. The breeder reactor in electricity supply

    International Nuclear Information System (INIS)

    Forecasts are made of Britain's energy prospects in the year 2000. It is concluded that fossil fuels and renewable energy sources will leave an energy gap and that dependence on nuclear power will be substantial. There will, however have been a rapid depletion of readily available uranium ore reserves and a growing availability of plutonium from thermal reactors. Britain's resources of plutonium and depleted uranium which the fast breeder reactor can use - will equal many thousand million tonnes of coal. Our nuclear programme should therefore include one or two FBRs. Resources should be pooled internationally and plants built to prove alternative options and consolidate an already highly developed technology. In Britain our earliest nuclear (Magnox) stations have served as well. In Scotland, where next year an estimated 30% of electricity output will be nuclear, Hunterston 'B' AGR has had a splendid first year of operation, and pumped storage capacity in Scotland has extended the benefits of low-cost generation. The FBR has many very satisfactory engineering features and is eminently controllable and well behaved. It is compact, with relatively low cooling-water requirements and it could be built, one hopes, close to our load centres. There can be confidence that it will be proved safe. An order for an FBR, on the earliest timescale that fits in with evidence of successful operation of the Dounreay PFR and an agreed international programme, would serve the national interest and ensure the survival of our plant manufacturers, so badly hit by the effects of stagnation of the U.K. economy. (author)

  7. A user's guide to COMULIP (a program for determining brick movements in an AGR core)

    International Nuclear Information System (INIS)

    COMULIP (COre Movements Using LInear Programming) is a set of computer programs which allows the user to find the maximum movements of bricks in a layer of 16 sided polygonal bricks and 4 sided interstitial bricks, as in the core of the Hinkley 'B' Advanced Gas Cooled Reactor. The user supplies the dimensions of the bricks and keys, the boundary constraints and specifies the brick and direction for which the maximum movement is to be found. To facilitate data input, a standard set of dimensions is entered together with individual brick dimensions which differ. The linear programming method is used to maximise an objective function, which in this case is the movement of a specified brick in a given direction, subject to a set of linear constraints, which define the geometrical condition that no brick should overlap. The elasticity of the bricks is not taken into account, the effect of this being small compared with that of the clearances. The model analysed is a two dimensional horizontal cross-section through the core. This report forms the user's guide to the computer programs and gives details of the input data required and the output produced, as well as a brief description of the solution technique. The program may be used to study the effect of dimensional changes and brick or key damage, which occur during the lifetime of the reactor, on the movement of bricks. (author)

  8. Metodologías para establecer valores de referencia de metales pesados en suelos agrícolas: perspectivas para Colombia

    Directory of Open Access Journals (Sweden)

    Germán Rueda Saa

    2011-07-01

    Full Text Available Los impactos ambientales de los metales pesados en los suelos están relacionados con su carácter tóxico cuando se acumulan o interactúan con algunas propiedades específicas, se movilizan a través del perfil a la cadena trófica mediante los cuerpos de agua o los cultivos y pueden llegar a afectar la salud humana. En países desarrollados el establecimiento de valores de referencia de estos metales ha permitido el mejoramiento de la planeación y la gestión ambiental del recurso suelo, y se ha convertido en un instrumento de control para las entidades ambientales que ha permitido evaluar el impacto en diferentes actividades agrícolas. En este artículo se analizan diversos conceptos relacionados con los niveles de metales pesados en suelos agrícolas y la incidencia de las características edafológicas en su concentración. Se revisan, igualmente, algunas metodologías para derivar valores de referencia específicos aplicables a suelos agrícolas colombianos, y se plantean algunas perspectivas orientadas a la protección y recuperación de suelos en el país. En Colombia en la actualidad no se cuenta con criterios y estándares de calidad para medir la contaminación por metales pesados en suelos agrícolas; por esto se hace necesario gestionar el apoyo de entidades gubernamentales con el fin de iniciar y desarrollar investigaciones en diferentes sectores agrícolas primarios, contribuyendo de esta forma a garantizar una producción más limpia y la sostenibilidad ambiental del recurso suelo.

  9. Plano de marketing Casa Agrícola Condes de Seia, S.A. 2012-2013

    OpenAIRE

    Manoel, Carolina Maria Santiago D'Orey

    2012-01-01

    Mestrado em Marketing O plano de marketing apresentado neste trabalho refere-se à Casa Agrícola Condes de Seia, S.A.. Tem como principais objectivos o aumento de vendas bem como a manuten-ção de relacionamentos duradouros, mutuamente vantajosos, com associações de produ-tores e com clientes que operam nesta área. O plano contém uma breve descrição da empresa, seguida da análise da situação. Esta inclui as análises interna e externa, missão, objectivos, ramos de actividade, análise SWOT,...

  10. Utilització de l'oli de colza com a biocarburant en explotacions agrícoles

    OpenAIRE

    Esteban Dalmau, Bernat; Baquero Armans, Grau; Puig Vidal, Rita; Riba Ruiz, Jordi-Roger; Rius Carrasco, Antoni

    2010-01-01

    La utilització de l’oli de colza com a carburant és una tecnologia que ja s’utilitza a altres països europeus com Alemanya i Dinamarca, degut principalment a dos factors: el gasoil agrícola està menys subvencionat i el grau de conscienciació mediambiental és major en aquest països. L’oli de colza és un biocarburant que s’obté del premsat de llavors de plantes oleaginoses i que, realitzant una petita modificació al sistema d’alimentació dels motors dièsel, pot ser utilitzat com a comb...

  11. Representações do universo rural e luta pela reforma agrária no Leste de Minas Gerais

    Directory of Open Access Journals (Sweden)

    Maria Eliza Linhares Borges

    2004-01-01

    Full Text Available O presente artigo se propõe a analisar o movimento de mobilização e organização político-ideológica dos setores subalternos do campo, no Vale do Rio Doce, região leste de Minas Gerais no imediato pré-golpe de 1964. Interessa-nos, especificamente, analisar as representações de mundo dos camponeses mostrando como elas orientaram suas formas de luta pela reforma agrária naquele período.The article analyzes the movement of political-ideological mobilization and organization of the subaltern rural sectors in the Rio Doce Valley, east of the state of Minas Gerais, Brazil, just before the 1964 coup. It aims specifically to analyze the worldviews of the peasants, showing how such views oriented their forms of struggle for land reform at that period.

  12. Fuentes de crecimiento del empleo en el sector agrícola del norte de México

    Directory of Open Access Journals (Sweden)

    José Alberto Salazar García

    2001-01-01

    Full Text Available El desempleo de mano de obra es uno de los problemas más agudos que actualmente enfrentan las zonas rurales de México. Con la finalidad de determinar cómo el cambio en la estructura productiva del sector agrícola del norte de México ha afectado el empleo rural de la región, se calculan las fuentes de crecimiento del empleo de mano de obra de 1991 a 1998. Los resultados indican que en Baja California, Chihuahua y Sonora el cambio en la estructura productiva fue positivo al empleo, mientras que en Coahuila, Sinaloa y Tamaulipas fue negativo. A nivel regional el cambio en la estructura productiva fue desfavorable al empleo; sin embargo, de 1991 a 1998 éste creció en 7.5 millones de jornadas a causa de un aumento en la superficie cosechada en 382 mil hectáreas.

  13. Mecanización agrícola ¿Deterioro o conservación del suelo?

    OpenAIRE

    Armando Alvarado Chaves

    2006-01-01

    “Mecanización agrícola; ¿Deterioro o conservación del suelo?” trata sobre el mito de que la mecanización o preparación de los suelos, en forma mecánica, es el detonante del deterioro de los suelos por erosión sobre todo por erosión hídrica y en menor grado por erosión eólica. La erosión de los suelos puede ser de poca o de gran magnitud, dependiendo de cuatro factores, los cuales se analizan como errores que se cometen en el momento de preparar los suelos. Estos errores son, en realidad, los ...

  14. Pertinencia social, evaluación y acreditación del agrónomo mexicano

    OpenAIRE

    Liberio Vicorino Ramírez; Gisela Judith Flores Leyva

    2004-01-01

    El objetivo del presente artículo es hacer una contribución a las propuestas sobre la formación de los profesionales de la agronomía, así como destacar el papel que en ellas juegan las diferentes vertientes que se conocen sobre la formación profesional del ingeniero agrónomo en México, en el contexto de la globalización y su consecuente pertinencia social. De manera complementaria, el propósito de este trabajo también es destacar la importancia de los procesos de evaluación y acreditación en ...

  15. Centre d’Investigació i Capacitació Agrària al Clot del Moro

    OpenAIRE

    Torras Montfort, Marc

    2012-01-01

    CICA neix amb la intenció de reanimar el Clot del Moro (Castella de n'Hug), partint d’una forta re-programació i seguint amb una proposta arquitectònica atrevida. La reprogramació del lloc mitjançant l’Escola de Capacitació Agrària i el Centre de Recerca, és clau per a la reanimació del lloc, ja que a part de ser viable pel lloc, aporten vida al llarg de tot el any al Centre. L’escola juntament amb la residència, ofereixen un ús diari del centre, compatible al mateix temps amb l’ús d...

  16. Staphylococcus epidermidis recovered from indwelling catheters exhibit enhanced biofilm dispersal and "self-renewal" through downregulation of agr

    DEFF Research Database (Denmark)

    Dai, Lu; Yang, Liang; Parsons, Chris;

    2012-01-01

    Background: In recent years, Staphylococcus epidermidis (Se) has become a major nosocomial pathogen and the most common cause of infections of implanted prostheses and other indwelling devices. This is due in part to avid biofilm formation by Se on device surfaces. However, it still remains unknown...... that how the process of Se biofilm development is associated with relapsed infection in such patients.Results: We have identified clinical Se isolates displaying enhanced biofilm dispersal and self-renewal relative to reference strain. These isolates also exhibit enhanced initial cell attachment...... these features.Conclusions: Collectively, these data reveal the role of agr system in long-term biofilm development and pathogenesis during Se caused indwelling devices-related relapsed infection....

  17. Evaluación de residuos agrícolas para la producción del hongo Pleurotus ostreatus

    Directory of Open Access Journals (Sweden)

    María Bernarda Ruilova Cueva

    2014-01-01

    Full Text Available Se caracterizaron los residuos agrícolas de la provincia de Bolívar, Ecuador, desde el punto de vista de su composición físico-química para su empleo en el cultivo del hongo Pleurotus ostreatus. Los residuos agrícolas utilizados fueron: maíz, trigo, cebada, lenteja, bagazo de caña de azúcar y cascarilla de arroz. Se realizaron análisis de: humedad, cenizas, extracto etéreo, proteína, fibra, extracto libre de nitrógeno, fibra detergente neutra, fibra detergente ácida, lignina, celulosa, hemicelulosa y minerales. Los residuos presentaron valores de humedad entre 9,12 y 13,91 %, después de dos meses de almacenamiento. Por su naturaleza leñosa son ricos en fibra, celulosa, lignina y hemicelulosa. El contenido de carbono fluctuó entre 50,12 y 56,55 %, y es la fuente directa de energía para su metabolismo. El contenido de nitrógeno fue variable 0,38-1,29 %. Se cultivó el hongo en los sustratos analizados y en la producción obtenida se valoró la eficiencia biológica y proteína. Se obtuvo en la mayoría de los casos una relación directa entre el contenido de nitrógeno con la eficiencia biológica y la proteína en el hongo.

  18. Funciones agua rendimiento para 14 cultivos agrícolas en condiciones del sur de La Habana

    Directory of Open Access Journals (Sweden)

    Felicita González Robaina

    2013-01-01

    Full Text Available El estudio de las funciones agua rendimiento y su uso dentro de la planificación del uso del agua es una vía importante para trazar estrategias de manejo que contribuyan al incremento en la producción agrícola. Utilizando los datos de consumo de agua, agua aplicada por riego, precipitaciones y los rendimientos obtenidos en más de 100 experimentos de campo realizados fundamentalmente en suelo Ferralítico Rojo de la zona sur de La Habana y con ayuda de herramientas de análisis de regresión en este trabajo se estiman las funciones rendimientos versus agua aplicada para 14 cultivos agrícolas. Respuestas de tipo lineal fueron encontradas para los cultivos de frijol, sorgo, ajo, cebolla, boniato, malanga y piña al relacionar el rendimiento con el agua aplicada por riego. Para los cultivos soya, pimiento, tomate, papa, plátano y banano esta relación se explica mejor a través de funciones cuadráticas. Para el caso particular del maíz, se propone la función por partes con un punto de ruptura alrededor de los 185 mm como mejor opción para explicar la respuesta al riego. Las funciones obtenidas pueden servir como herramientas para alcanzar los rendimientos potenciales de los cultivos estudiados y en la toma de decisiones cuando el recurso agua está limitado.

  19. Detecção de áreas agrícolas em tempo quase real com imagens Modis

    Directory of Open Access Journals (Sweden)

    Isaque Daniel Rocha Eberhardt

    2015-07-01

    Full Text Available Resumo: O objetivo deste trabalho foi desenvolver um método para identificação e monitoramento, em tempo quase real, de áreas agrícolas cultivadas com lavouras temporárias de verão, com uso de imagens orbitais Modis, no Estado do Rio Grande do Sul. A metodologia foi denominada detecção de áreas agrícolas em tempo quase real (DATQuaR e utiliza imagens do sensor Modis referentes aos índices de vegetação (IVs EVI e NDVI, disponibilizadas em composições de 16 dias. Foram utilizadas quatro métricas para agregar os valores de IVs por pixel, dentro dos períodos bimensais avaliados: média, máximo, mínimo e mediana. Para gerar as imagens (ImDATQuaR, a imagem agregada para o período imediatamente anterior foi subtraída da imagem agregada para o período em monitoramento. Essas imagens foram classificadas por meio de fatiamento e comparadas às classes de referência obtidas pela interpretação visual de pixels aleatorizados em imagens Landsat. Cada ImDATQuaR gerou dois mapas DATQuaR: um com filtragem de moda com janela 3x3 pixels e outro sem filtragem. O melhor mapa DATQuaR é produzido com uso de imagens EVI e filtragem - ao se subtrair a imagem de mínimo valor para o período anterior da imagem de máximo valor para o período monitorado - e atinge concordâncias com a referência superiores a 81%.

  20. Análisis conceptual del uso agrícola del suelo: Su incidencia en la sostenibilidad

    Directory of Open Access Journals (Sweden)

    Maldané Cuello Espinosa

    2013-05-01

    Full Text Available El tema del desarrollo sostenible ha sido muy discutido y analizado en las últimas décadas; no obstante, aún no se ha desarrollado satisfactoriamente; se inició en el año de 1987 con el informe Brundtland denominado Nuestro futuro común, de la Comisión Mundial para el Medio Ambiente. En el informe se puntualiza y se define concretamente al desarrollo sostenible como: “Satisfacer las necesidades del presente sin comprometer la capacidad de satisfacer las futuras generaciones”. En la actualidad, casi todas las personas coinciden con tan importante definición; sin embargo, no se ha plasmado a los niveles que se requiere para deshacer los trances que se exhiben en ese sentido a escala mundial, fruto de los ambiciosos intereses particulares.  El suelo es uno de los recursos que, en condiciones ambientalmente normales, bien puede llenar las expectativas de poder llevar a la praxis tan anhelada descripción, integrando con perspectiva de sistema agrícola los tres elementos claves que la componen: el elemento social, el económico y el ambiental.  El desarrollo de los sistemas agrícolas y sus aplicaciones e implicaciones en el proceso de la sostenibilidad, trae consigo cambios considerables en términos social, económico y ambiental, que, indudablemente, contribuye a tan anhelado proceso, en el sentido de poder lograr un cambio en el entorno común, alcanzando a armonizar la naturaleza, los beneficios económicos y las necesidades de la población.

  1. Influencia de cuatro distancias de trasplante sobre el rendimiento agrícola del cultivar de arroz Amistad-82.

    Directory of Open Access Journals (Sweden)

    Alexander Calero Hurtado

    2012-04-01

    Full Text Available El trabajo consistió en comparar cuatro distancias de trasplante sobre el rendimiento agrícola del cultivar de arroz Amistad-82, durante la siembra de primavera de 2012, el trasplante se realizó de forma manual, sobre un suelo pardo sialítico carbonatado en la finca “La Rosita” perteneciente a la CCS “Heriberto Orellane”, en la provincia de Sancti Spíritus, se utilizó un diseño de bloques al azar, se tomaron posturas jóvenes de 18 días de germinadas, cuatro distancias de plantación 10x15, 15x15, 20x15 y 20x20 cm y una postura por sitio. Se evaluaron los indicadores productivos como el número de tallos, panículas por metro cuadrado, longitud de la panícula, granos por panículas, granos llenos y vanos por panículas, peso de 1000 granos, el rendimiento, así como las ganancias y los costos de producción. Los mejores resultados sobre el rendimiento agrícola del cultivar de arroz Amistad-82 lo alcanzaron las distancias de trasplante 10x15 y 20x15 cm, porque lograron rendimientos superiores a las distancias 15x15 y 20x20 cm, mayor cantidad de granos por panículas y mayores porcentajes de granos llenos por panículas y superaron también el peso en 1000 granos y las ganancias.

  2. A experiência norte-americana com o seguro agrícola: lições ao Brasil?

    Directory of Open Access Journals (Sweden)

    Marcelo Fernandes Guimarães

    2009-03-01

    Full Text Available O seguro agrícola é um instrumento eficaz de gestão de riscos rurais. Paradoxalmente, sua utilização pelos agricultores é relativamente reduzida em quase todo o mundo. Uma notória exceção é os Estados Unidos da América, país onde essa modalidade alcançou reconhecido sucesso. O processo, porém, foi lento, muito dispendioso e envolveu a participação determinante do Estado em diversas ações complementares. Dessa forma, países que desejam incluir esse instrumento dentre as prioridades de sua política agrícola, como parece ser o caso brasileiro, devem estar atentos aos requisitos para o seu sucesso e aos resultados e problemas gerados ou ampliados por sua massificação. O estudo da experiência norte-americana fornece lições relevantes.Agricultural insurance is considered to be an effective to manage rural risks. Surprisingly, its adoption by farmers is very limited all over the world. An outstanding exception is the United States of America, country in which this instrument has achieved remarkable success. Nevertheless, the process of diffusion of agricultural insurance in the USA was slow and expensive. It has also required significant government intervention through a variety of complementary actions. In this context, countries willing to introduce this instrument among other agricultural policy tools, as it seems the case of Brazil, should proceed with caution. Agricultural insurance success has important pre-requisites and its general diffusion may amplify its problems. The analysis of the North American experience provides worthwhile lessons.

  3. Cooperativa-escola nas Escolas Técnicas Agrícolas Cooperative-school at the Agricultural Technical Schools

    Directory of Open Access Journals (Sweden)

    P.V. Marques

    1993-12-01

    Full Text Available A dificuldade de gerenciar recursos e proporcionar melhores condições de ensino para os estudantes são algumas das deficiência das Escolas Técnicas Agrícolas (ETAs brasileiras, problemas parcialmente superados por algumas escolas que adotaram a chamada Cooperativa-Escola. Neste trabalho, procura-se discutir alguns aspectos filosóficos referentes às ETAs e como a Cooperativa-Escola pode ajudar a solucionar seus principais problemas educativos e administrativos; um estudo de caso utilizando-se a técnica de auditoria administrativa foi desenvolvido numa ETA cuja Cooperativa-Escola é considerada um modelo de bom funcionamento e alguns procedimentos foram descritos, objetivando-se estender a prática de Cooperativa-Escola para outras escolas técnicas agrícolas brasileiras.Some of the problems with the Brazilian public Agricultural Technical School systems (ETAs are related to resource management and the need to improve teaching and learning conditions. Those deficiencies were partially corrected after setting up Cooperative-Schools that allow the ETAs to raise and to administrate funds. Administrative procedures of the ETAs and how the Cooperative-School could help solving their main educational and adminsitrative problems are discussed in this research. A case study using the management audit technique was developed in one ETA with a well known Cooperative-School. Some observed procedures are described with the intention of extending the practice of Cooperative-Schools to other Brazilian Agricultural Technical Schools.

  4. A review of the United Kingdom fast reactor programme

    International Nuclear Information System (INIS)

    Total energy consumption in the UK in 1989 was 340 million tonnes of coal or coal equivalent, made up as follows: coal 31%, petroleum 35%, natural gas 24%, nuclear electricity 8%, hydroelectricity 1% and imported electricity 1%. About half of the nuclear electricity generated came from 14 Advanced Gas-Cooled Reactors (AGRs) and about half from the 24 older gas-cooled Magnox reactors, one Steam-Generating Heavy-Water Reactor (SGHWR) and one fast reactor (the Prototype Fast Reactor, PFR, at Dounreay). The privatization of the Electricity Supply Industry (ESI) in the UK is proceeding. On 9 November 1989, however, it was announced by the Secretary of State for Energy that the privatization plan would be changed and that the CEGB's nuclear stations were to remain in state ownership, through the formation of an additional company, Nuclear Electric. At the same time, the Secretary of State for Scotland announced the formation of a similar state-owned company, Scottish Nuclear. Nuclear Electric was asked, in the interim, to examine priorities in the whole nuclear field with particular reference to the improvement of the economics and performance of existing reactors, to the development of the Sizewell and alternative reactors and to the development of longer-term options such as the fast reactor and fusion. Nuclear Electric has been asked to formulate its new policy by June 1990. The PFR programme will continue to be funded by the UK government until March 1994. AEA Technology is endeavouring to find alternative funding to maintain the operation of the PFR until at least the year 2000. The House of Commons Select Committee on Energy stated in its report that the fast reactor ''is a matter for the British Government to foster as a long-term option for the generation of electricity in this country'', and recommended that in the interim the Government reassesses its position on this new technology in the light of increasing concern about CO2 emissions and the long

  5. Research Nuclear Reactors

    International Nuclear Information System (INIS)

    Published in English and in French, this large report first proposes an overview of the use and history of research nuclear reactors. It discusses their definition, and presents the various types of research reactors which can be either related to nuclear power (critical mock-ups, material test reactors, safety test reactors, training reactors, prototypes), or to research (basic research, industry, health), or to specific particle physics phenomena (neutron diffraction, isotope production, neutron activation, neutron radiography, semiconductor doping). It reports the history of the French research reactors by distinguishing the first atomic pile (ZOE), and the activities and achievements during the fifties, the sixties and the seventies. It also addresses the development of instrumentation for research reactors (neutron, thermal, mechanical and fission gas release measurements). The other parts of the report concern the validation of neutronics calculations for different reactors (the EOLE water critical mock-up, the MASURCA air critical mock-up dedicated to fast neutron reactor study, the MINERVE water critical mock-up, the CALIBAN pulsed research reactor), the testing of materials under irradiation (OSIRIS reactor, laboratories associated with research reactors, the Jules Horowitz reactor and its experimental programs and related devices, irradiation of materials with ion beams), the investigation of accident situations (on the CABRI, Phebus, Silene and Jules Horowitz reactors). The last part proposes a worldwide overview of research reactors

  6. Reactor Physics Training

    International Nuclear Information System (INIS)

    University courses in nuclear reactor physics at the universities consist of a theoretical description of the physics and technology of nuclear reactors. In order to demonstrate the basic concepts in reactor physics, training exercises in nuclear reactor installations are also desirable. Since the number of reactor facilities is however strongly decreasing in Europe, it becomes difficult to offer to students a means for demonstrating the basic concepts in reactor physics by performing training exercises in nuclear installations. Universities do not generally possess the capabilities for performing training exercises. Therefore, SCK-CEN offers universities the possibility to perform (on a commercial basis) training exercises at its infrastructure consisting of two research reactors (BR1 and VENUS). Besides the organisation of training exercises in the framework of university courses, SCK-CEN also organizes theoretical courses in reactor physics for the education and training of nuclear reactor operators. It is indeed a very important subject to guarantee the safe operation of present and future nuclear reactors. In this framework, an understanding of the fundamental principles of nuclear reactor physics is also necessary for reactor operators. Therefore, the organisation of a basic Nuclear reactor physics course at the level of reactor operators in the initial and continuous training of reactor operators has proven to be indispensable. In most countries, such training also results from the direct request from the safety authorities to assure the high level of competence of the staff in nuclear reactors. The objectives this activity are: (1) to provide training and education activities in reactor physics for university students and (2) to organise courses in nuclear reactor physics for reactor operators

  7. Introduction of Nuclear Reactor Engineering

    International Nuclear Information System (INIS)

    This book introduces development, status, supply and demand and resource of nuclear reactor. It deals with basic knowledge of nuclear reactor, which are reactor system, heat recovery in reactor core, structural feature in reactor, materials of structure in reactor, shielding of gamma ray, shielding of reactor, safety and environmental problem of nuclear power plant, nuclear fuel and economical efficiency of nuclear energy.

  8. Modelagem matemática para seleção de conjuntos mecanizados agrícolas pelo menor custo operacional Mathematical modeling to select mechanized agricultural systems by the lowest operational cost

    OpenAIRE

    Fábio H.R. Baio; Andrew D. Rodrigues; Gilson S. dos Santos; Simone P. da Silva

    2013-01-01

    A seleção de uma máquina agrícola pode tornar-se uma tarefa árdua, pois há diversas variáveis que devem ser consideradas. A escolha do equipamento mais adequado para uma propriedade agrícola é uma das etapas mais importantes do processo produtivo. O objetivo deste trabalho foi desenvolver um modelo de computador por programação linear em plataforma web para seleção automatizada de conjuntos mecanizados agrícolas, baseados no menor custo operacional. O programa, desenvolvido em linguagem ASP.N...

  9. Fatigue crack growth and endurance data on 9% Cr 1% Mo steels for AGR applications

    International Nuclear Information System (INIS)

    Experimental investigations have been carried out on 9%Cr 1%Mo steels to examine: (1) The significance of carburisation on the fatigue endurance of plain and welded boiler tubes, and tube spacer strip; (2) the high cycle fatigue endurance of spacer strip and spacer weld metal; (3) fatigue crack growth rates in spacer strip and spacer weld metal. This report summarises the results of these investigations and where necessary compares the data to that in current data sheets. The effects of carburisation are variable depending on the structure and type of carburisation. The fatigue endurance properties of spacer strip and spacer weld metal are also similar and need not be considered separately for assessment or design purposes. Fatigue crack growth rates in spacer strip and space weld metal are similar and are influenced by both stress ratio and temperature. A design curve from a fast reactor data sheet may be used as an upper bound to these fatigue crack growth results. (author)

  10. The calculation of methane profiles in AGR graphite structures. Part I: cylindrical geometry

    International Nuclear Information System (INIS)

    A mathematical model has been developed to simulate the diffusion, permeable flow and radiolytic destruction of methane in graphite specimens utilised in the Advanced Gas Cooled Reactor development programme. The integration of the diffusion equations governing the rate of mass transport is carried out by the Harwell FACSIMILE program and in its simple form the model has shown good agreement with analytical solutions. The model has been extended to take into account the changes in water and carbon monoxide concentrations resulting from radiolytic reactions within the system and the magnitude of these effects has been assessed. A simple method for the introduction of the effect of water production arising directly from the methane destruction process has been derived and a technique for calculating the gas-in-gas diffusion coefficients for the migrating species from the molecular theory of gases is outlined. (author)

  11. Geografia da riqueza, fome e meio ambiente: pequena contribuição crítica ao atual modelo agrário/agrícola de uso dos recursos naturais

    Wealth geography, environment and hunger: small critic contribution to the current agrarian/agricultural model of the natural resources usage

    OpenAIRE

    Carlos Walter Porto Gonçalves

    2004-01-01

    PortuguesO texto discute a questão geopolítica implicada no debate sobre a fome e o meio ambiente. Critica o atual modelo agrário/agrícola de uso dos recursos naturais, afirma ser este um modelo de desenvolvimento econômico das regiões temperadas que tem sido imposto com um alto custo ecológico, cultural e político para o mundo todo. Este modelo tem se colocado em confronto com o conhecimento patrimonial, coletivo e comunitário característico de populações com racionalidades distintas da raci...

  12. Safeguarding research reactors

    International Nuclear Information System (INIS)

    The report is organized in four sections, including the introduction. The second section contains a discussion of the characteristics and attributes of research reactors important to safeguards. In this section, research reactors are described according to their power level, if greater than 25 thermal megawatts, or according to each fuel type. This descriptive discussion includes both reactor and reactor fuel information of a generic nature, according to the following categories. 1. Research reactors with more than 25 megawatts thermal power, 2. Plate fuelled reactors, 3. Assembly fuelled reactors. 4. Research reactors fuelled with individual rods. 5. Disk fuelled reactors, and 6. Research reactors fuelled with aqueous homogeneous fuel. The third section consists of a brief discussion of general IAEA safeguards as they apply to research reactors. This section is based on IAEA safeguards implementation documents and technical reports that are used to establish Agency-State agreements and facility attachments. The fourth and last section describes inspection activities at research reactors necessary to meet Agency objectives. The scope of the activities extends to both pre and post inspection as well as the on-site inspection and includes the examination of records and reports relative to reactor operation and to receipts, shipments and certain internal transfers, periodic verification of fresh fuel, spent fuel and core fuel, activities related to containment and surveillance, and other selected activities, depending on the reactor

  13. Research nuclear reactors

    International Nuclear Information System (INIS)

    Since the divergence of the first nuclear reactor in 1942, about 600 research or test reactors have been built throughout the world. Today 255 research reactors are operating in 57 countries and about 70% are over 25 years old. Whereas there are very few reactor types for power plants because of rationalization and standardisation, there is a great diversity of research reactors. We can divide them into 2 groups: heavy water cooled reactors and light water moderated reactors. Heavy water cooled reactors are dedicated to the production of high flux of thermal neutrons which are extracted from the core by means of neutronic channels. Light water moderated reactors involved pool reactors and slightly pressurized closed reactors, they are polyvalent but their main purposes are material testing, technological irradiations, radionuclide production and neutron radiography. At the moment 8 research reactors are being built in Canada, Germany, Iran, Japan, Kazakhstan, Morocco, Russia and Slovakia and 8 others are planned in 7 countries (France, Indonesia, Nigeria, Russia, Slovakia, Thailand and Tunisia. Different research reactors are described: Phebus, Masurca, Phenix and Petten HFR. The general principles of nuclear safety applied to test reactors are presented. (A.C.)

  14. Necesidades educacionales sobre riesgo de plaguicidas en el contexto socio-ambiental de las comunidades agrícolas de Sonora

    Directory of Open Access Journals (Sweden)

    M.I. Silveira Gramont

    2016-01-01

    Full Text Available Para proponer estrategias de educación y comunicación sobre plaguicidas en las comunidades agrícolas de Sonora, se requiere situar la problemática de la exposición a plaguicidas en el contexto socio-cultural y ambiental de las comunidades afectadas, tomando en cuenta los factores que contribuyen al mayor riesgo de exposición de los trabajadores agrícolas y de sus familias. Este estudio examina los factores poblacionales, educacionales, culturales y de trabajo de habitantes y trabajadores agrícolas de dichas comunidades, así como las limitaciones de infraestructura comunitaria y de condiciones de vivienda en relación al riesgo de contaminación por plaguicidas. Sobre la base de este análisis se proponen posibles alternativas educacionales orientadas a mitigar tal riesgo en el contexto socio-cultural de dichas comunidades. Método De los estudios reportados sobre la presencia de residuos de plaguicidas en productos agrícolas y acuícolas, en suelos, agua, medio ambiente y en líquidos corporales de niños y adultos de Sonora, se puede concluir que tanto los trabajadores agrícolas como la población que reside cerca de las zonas agrícolas, están sujetos a un mayor riesgo de contaminación por plaguicidas. Para la realización del presente estudio se seleccionaron cinco comunidades localizadas en los valles agrícolas más productivos de Sonora, en las cuales se han llevado a cabo investigaciones relacionadas con plaguicidas. Básicamente, se analizó la información obtenida de encuestas aplicadas a residentes y trabajadores agrícolas de dichas comunidades, para explorar su conocimiento sobre uso y manejo de plaguicidas, percepción del riesgo que tales sustancias representan y las prácticas de protección personal que llevan a cabo para la prevención de dichos riesgos (en el hogar y trabajo. También se describe la infraestructura de los poblados y las viviendas de sus habitantes en relación al potencial de riesgo de contaminaci

  15. Nuclear reactor building

    International Nuclear Information System (INIS)

    Purpose: To prevent seismic vibrations of external buildings from transmitting to the side walls of a reactor container in a tank type FBR reactor building. Constitution: The reactor building is structured such that the base mat for a reactor container chamber and a reactor container is separated from the base mat for the walls of building, and gas-tight material such as silicon rubber is filled in the gap therebetween. With such a constitution, even if the crane-supporting wall vibrates violently upon occurrence of earthqualkes, the seismic vibrations do not transmit toward the reactor container chamber. (Horiuchi, T.)

  16. Histórico e os limites da reforma agrária na contemporaneidade brasileira History and limits of the agrarian reform in the Brazilian contemporary time

    Directory of Open Access Journals (Sweden)

    Paulo Nakatani

    2012-06-01

    Full Text Available Objetiva-se reconstituir a trajetória da questão fundiária (e agrária na experiência de maior concentração de riqueza e recursos vivenciada no âmbito do sistema capitalista, partindo-se da premissa de que a crescente desigualdade do modelo brasileiro passa necessariamente pela questão agrária. Num segundo momento, procede-se à análise dos limites atualmente colocados a qualquer possibilidade de uma Reforma Agrária ampla e estrutural, dados pelo avanço do agronegócio nos últimos dez anos, pela desmobilização política de parcela significativa da sociedade no que se refere a esta questão e pelos próprios limites estruturais da economia brasileira nos quadros da globalização financeira. O texto será dividido em seis sessões: a colonização e origens do latifúndio; b O modelo agroexportador e a ruptura incompleta; c a questão agrária e a industrialização brasileira; d a questão agrária e o agronegócio; e os limites da reforma agrária na contemporaneidade; f considerações finais.This paper aims at reconstructing the history of the land (agrarian issue considering the greatest concentration of wealth and resources in the capitalist system. The standpoint is that the growing inequality of the Brazilian model is related to the agrarian issue. Secondly, we analyze the limits ­currently placed on any possibility of a comprehensive and structural agrarian reform, due to the advancement of the agribusiness over the last ten years, the political demobilization of a significant portion of society that put this issue aside, and the limits of the Brazilian economy in the context of the financial globalization. The paper is divided into six parts: a colonization and origins of the large landed estates; b the agro-export model and the incomplete rupture; c the agrarian issue and the Brazilian industrialization; d the agrarian issue and the agribusiness; e the limits of the agrarian reform in the contemporary time; f final

  17. Reactor Physics Programme

    International Nuclear Information System (INIS)

    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

  18. Ship propulsion reactors technology

    International Nuclear Information System (INIS)

    This paper takes the state of the art on ship propulsion reactors technology. The french research programs with the corresponding technological stakes, the reactors specifications and advantages are detailed. (A.L.B.)

  19. Undergraduate reactor control experiment

    International Nuclear Information System (INIS)

    A sequence of reactor and related experiments has been a central element of a senior-level laboratory course at Pennsylvania State University (Penn State) for more than 20 yr. A new experiment has been developed where the students program and operate a computer controller that manipulates the speed of a secondary control rod to regulate TRIGA reactor power. Elementary feedback control theory is introduced to explain the experiment, which emphasizes the nonlinear aspect of reactor control where power level changes are equivalent to a change in control loop gain. Digital control of nuclear reactors has become more visible at Penn State with the replacement of the original analog-based TRIGA reactor control console with a modern computer-based digital control console. Several TRIGA reactor dynamics experiments, which comprise half of the three-credit laboratory course, lead to the control experiment finale: (a) digital simulation, (b) control rod calibration, (c) reactor pulsing, (d) reactivity oscillator, and (e) reactor noise

  20. Process heat reactors

    International Nuclear Information System (INIS)

    The consumption of heat, for industrial and domestic needs, takes up half of the national energy supply; direct utilization of the heat produced by nuclear reactors could therefore contribute to reduce the deficit in the energetic results. The restraints proper to heat consumption (dispersal and variety of consumers, irregular demand) involve the development of the heat transport system structures and adequate nuclear reactors. With this in view, the Commissariat a l'Energie Atomique and Technicatome are developing the CAS reactor series, pressurized water reactors (PWR), (CAS 3G reactor with a power of 420 MW.th.), and the Thermos reactor (100 MW.th.), directly conceived to produce heat at 1200C and whose technology derives from the experimental pool reactors type. In order to prove the value of the Thermos design, an experimental reactor should soon be constructed in the Saclay nuclear research centre

  1. Reactor System Design

    International Nuclear Information System (INIS)

    SMART NPP(Nuclear Power Plant) has been developed for duel purpose, electricity generation and energy supply for seawater desalination. The objective of this project IS to design the reactor system of SMART pilot plant(SMART-P) which will be built and operated for the integrated technology verification of SMART. SMART-P is an integral reactor in which primary components of reactor coolant system are enclosed in single pressure vessel without connecting pipes. The major components installed within a vessel includes a core, twelve steam generator cassettes, a low-temperature self pressurizer, twelve control rod drives, and two main coolant pumps. SMART-P reactor system design was categorized to the reactor coe design, fluid system design, reactor mechanical design, major component design and MMIS design. Reactor safety -analysis and performance analysis were performed for developed SMART=P reactor system. Also, the preparation of safety analysis report, and the technical support for licensing acquisition are performed

  2. The discovery by Gh. Benga of the first water channel protein in 1985 in Cluj-Napoca, Romania, A few years before P. Agre (2003 Nobel Prize in Chemistry).

    Science.gov (United States)

    Cucuianu, M

    2006-01-01

    The first water channel protein, now called aquaporin 1, was identified or "seen" in situ in the human red blood cell membrane by Benga's group in 1985. It was again "seen" when it was by chance purified by Agre'group in 1988 and was again identified when its main feature, the water transport property, was found by Agre's group in 1992. Consequently, the omission of Gh. Benga from the 2003 Nobel Prize in Chemistry (half of which was awarded to P. Agre "for the discovery of the water channels") is a new mistake in the award of Nobel Prizes. The growing recognition of the priority of Gh. Benga over P. Agre in the discovery of water channels is documented in this paper. PMID:18386610

  3. The experimental qualification of a mathematical model used to assess the AGR core seismic response

    International Nuclear Information System (INIS)

    The seismic response of the graphite bricks contained in an Advanced Gas Cooled Reactor core has been determined analytically using a computer code, AGRCOR. The development of this code and the analysis techniques implemented within it are subjects of another paper. A test programme was undertaken to qualify AGRCOR and involved shaker table excitation of increasingly complex arrays of both sliced and full height bricks. The measured responses were then compared with those computed. Both single and multi-axis sinusoidal and earthquake excitation has been used. This paper describes the procedures used to test the more complex, full height brick arrays and discusses the correlation obtained between the measured and computed data. Generally, the agreement was found to be within the error bands calculated by combining all potential experimental and computational errors. Therefore the code was considered to be validated for these cases. In all other cases, the code results were found to be too high, hence conservative, by factors of up to x 4. (author)

  4. Nuclear Reactor RA Safety Report, Vol. 11, Reactor operation

    International Nuclear Information System (INIS)

    This volume includes the following chapters describing: Organisation of reactor operation (including operational safety, fuel management, and regulatory rules for RA reactor operation); Control and maintenance of reactor components (reactor core, nuclear fuel, heavy water and cover gas systems, mechanical structures, electric power supply system, reactor instrumentation); Quality assurance and Training of the reactor personnel

  5. The Chernobylsk reactor accident

    International Nuclear Information System (INIS)

    The construction, the safety philosophy, the major reactor physical parameters of RBMK-1000 type reactor units and the detailed description of the Chernobylsk-4 reactor accident, its causes and conclusions, the efforts to reduce the consequences on the reactor site and in the surroundings are discussed based on different types of Soviet documents including the report presented to the IAEA by the Soviet Atomic Energy Agency in August 1986. (V.N.)

  6. Zero energy reactor 'RB'

    International Nuclear Information System (INIS)

    In 1958 the zero energy reactor RB was built with the purpose of enabling critical experiments with various reactor systems to be carried out. The first core assembly built in this reactor consists of heavy water as moderator and natural uranium metal as fuel. In order to be able to obtain very accurate results when measuring the main characteristics of the assembly the reactor was built as a completely bare system. (author)

  7. High solids fermentation reactor

    Science.gov (United States)

    Wyman, Charles E.; Grohmann, Karel; Himmel, Michael E.; Richard, Christopher J.

    1993-01-01

    A fermentation reactor and method for fermentation of materials having greater than about 10% solids. The reactor includes a rotatable shaft along the central axis, the shaft including rods extending outwardly to mix the materials. The reactor and method are useful for anaerobic digestion of municipal solid wastes to produce methane, for production of commodity chemicals from organic materials, and for microbial fermentation processes.

  8. Fossil nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Maurette, M.

    1976-01-01

    The discussion of fossil nuclear reactors (the Oklo phenomenon) covers the earth science background, neutron-induced isotopes and reactor operating conditions, radiation-damage studies, and reactor modeling. In conclusion possible future studies are suggested and the significance of the data obtained in past studies is summarized. (JSR)

  9. Fusion reactor studies

    International Nuclear Information System (INIS)

    A review is given of fusion reactor systems studies, the objectives of these studies are outlined and some recent conceptual reactor designs are described. The need for further studies in greater depth is indicated so that progress towards a commercial fusion reactor may be consolidated. (U.K.)

  10. Reactor power measuring device

    International Nuclear Information System (INIS)

    The present invention provides a self-powered long detector having a sensitivity over the entire length of a reactor core as an entire control rod withdrawal range of a BWR type reactor, and a reactor power measuring device using a gamma ray thermometer which scarcely causes sensitivity degradation. That is, a hollow protection pipe is disposed passing through the reactor core from the outside of a reactor pressure vessel. The self-powered long detectors and the gamma ray thermometers are inserted and installed in the protection pipe. An average reactor power in an axial direction of the reactor relative to a certain position in the horizontal cross section of the reactor core is determined based on the power of the self-powered long detector over the entire length of the reactor core. Since the response of the self-powered detector relative to a local power change is rapid, the output is used as an input signal to a safety protection device of the reactor core. Further, a gamma ray thermometer secured in the reactor and having scarce sensitivity degradation is used instead of an incore travelling neutron monitor used for relative calibration of an existent neutron monitor secured in the reactor. (I.S.)

  11. Preparation of 1-group nuclear data for AGR fault studies and partial investigation of the adequacy of 1-group calculations of fault transients

    International Nuclear Information System (INIS)

    A route for the preparation of 1-group nuclear data for AGR fault studies using SKARK is outlined. The route starts from an initial 2-group 3D static calculation and involves the use of pseudo-absorbers to force agreement of the initial 1-group flux with the 2-group total flux. With data prepared in this manner static 1-group and 2-group calculations for various regulating rod insertions have been compared. The 1-group calculations were found to exaggerate flux shape changes from the initial state compared to the 2-group calculations. These results are used to quantify some of the errors in using a 1-group description of AGR fault transients. (author)

  12. Etude de l'anisotropie d'échange dans des agrégats de cobalt nanométriques

    OpenAIRE

    Portemont, Céline

    2006-01-01

    Ce travail porte sur l'étude de l'anisotropie d'échange dans des agrégats de cobalt nanométriques (1-6 nm de diamètre) fabriqués par une source à pulvérisation magnétron et condensation en phase vapeur. Des mesures de microscopie électronique en transmission à haute résolution et de diffraction de rayons X montrent que les agrégats sont icosaédriques. Cette structure, confirmée par des calculs utilisant un modèle atomistique, est déformée de façon non homogène. L'anisotropie magnétique de ces...

  13. PRAPRAG: software para planejamento racional de máquinas agrícolas PRAPRAG: software for rational planning of agricultural machines

    OpenAIRE

    Erivelto Mercante; Eduardo G. de Souza; Jerry A. Johann; Antonio Gabriel Filho; Miguel A. Uribe-Opazo

    2010-01-01

    O software PRAPRAG é uma ferramenta de escolha de máquinas e implementos agrícolas que apresentam o menor custo por área ou por quantidade produzida, bem como, faz o planejamento de aquisição das máquinas para a propriedade agrícola, do ponto de vista técnico e econômico. Foi utilizada a linguagem de programação Borland Delphi 3.0 e, a partir de prospectos das máquinas e implementos, criou-se um banco de dados onde o usuário pode cadastrar e modificar suas características de uso. O software m...

  14. Assentamentos rurais na Amazônia: contradições entre a política agrária e a política ambiental

    OpenAIRE

    François-Michel Le Tourneau; Marcel Bursztyn

    2010-01-01

    A ação do INCRA na Amazônia revela um paradoxo: por mais que a ocupação humana daquela região fosse uma estratégia dos governos militares, é na fase democrática recente que a reforma agrária brasileira intensifica a instalação de agricultores em assentamentos. A institucionalização de políticas de proteção do meio ambiente se revela contraditória com as práticas de proteção social que têm, na Amazônia, um foco de destaque num modelo de reforma agrária que provoca inevitáveis consequências amb...

  15. Zonificación del Municipio Gibara, útil de trabajo para el comienzo de las actividades extensión agrícola.

    OpenAIRE

    Raciel Ojeda Fernández; Severo Aranda Aranda; Daimarelis Rodríguez Leyva

    2003-01-01

    Se expone la zonificación del municipio Gibara fundamentado en un análisis sistémico del medio donde se desarrolla la producción agropecuaria. Para conseguir este resultado se comenzó con la búsqueda de informaciones del medio físico, socioeconómico y agrícola del municipio. Posteriormente se confeccionaron mapas de hidrología, suelos, temperatura, vías de comunicación terrestres, pluviometría y prácticas agrícolas; a continuación se analizó la información contenida en cada mapa superponiéndo...

  16. Análise da quantidade de azoto em excesso em solos agrícolas na zona vulnerável n.º 1

    OpenAIRE

    Silva, Pedro F. S.; Haie, Naim

    2006-01-01

    O conceito de Zona Vulnerável com vista a proteger as águas contra a poluição difusa causada por nitratos de origem agrícola, foi definido na Directiva 91/676/CEE, publicada no Jornal Oficial das Comunidades de 31 de Dezembro de 1997, a qual foi transposta para a ordem jurídica interna pelo Dec-Lei 235/97 de 3 de Setembro. Os objectivos deste diploma são: a redução da poluição das águas contra a poluição causada por nitratos de origem agrícola, bem como impedir a propagação desta poluição (ar...

  17. Transmissões presentes em tratores agrícolas no Brasil Transmissions present in agricultural tractors in Brazil

    Directory of Open Access Journals (Sweden)

    Rodrigo Lampert Ribas

    2010-10-01

    Full Text Available O sistema de transmissão de um trator agrícola tem por principal finalidade transmitir a potência gerada no motor ao sistema hidráulico, à tomada de potência e às rodas motrizes. A caixa de câmbio é formada por uma série de engrenagens que permitem a correta seleção da velocidade e do torque mais adequados a uma determinada operação. Assim, as transmissões podem ser classificadas, basicamente, em três categorias: mecânicas, hidrostáticas e hidrodinâmicas, sendo as transmissões mecânicas subdivididas em engrenagens deslizantes e sincronizadas. Este trabalho objetivou analisar os diferentes tipos de transmissões disponibilizados em 169 modelos de tratores fabricados no Brasil, com a finalidade de avaliar a real distribuição nas diferentes faixas de potência e estabelecer possíveis relações entre esses parâmetros. Como resultado, evidencia-se uma forte tendência de tratores agrícolas com potência menor que 111,8kW possuírem transmissão do tipo mecânica, e tratores acima de 111,8kW, do tipo hidrostática.The transmission system of an agricultural tractor has a main purpose to transmit the power generated in the hydraulic motor, the power take off and the drive wheels. The gearshift consists of a series of gears that allows the correct selection of speed and torque more appropriate to a particular operation. Then, the transmissions can be classified, basically, in three categories: mechanical, hydrostatic and hydrodynamic, being the mechanical transmissions subdivided in sliding gear and synchronized. Then, the objective of this research was to analyze the different types of transmissions available in 169 models of tractors made in Brazil in order to evaluate the real distribution of them in different power ranges and establish possible correlations. As a result, it was shown a strong tendency for agricultural tractors with power less than 111.8kW possessing mechanical transmission and tractors above 111.8k

  18. Metodologia para estimar o número de dias trabalháveis com máquinas agrícolas

    Directory of Open Access Journals (Sweden)

    Javier Solis Estrada

    2015-08-01

    Full Text Available No atual modelo de agricultura, é indispensável que o produtor conheça a real disponibilidade de tempo para a execução das operações agrícolas ao longo do ciclo das culturas. Este é o primeiro passo para se planejar e se obter maior eficiência na execução dessas operações, que estão sujeitas às variações do clima. As variáveis meteorológicas de uma determinada região influenciam diretamente no número de dias disponíveis para trabalhar com máquinas agrícolas. O objetivo deste trabalho foi estimar as probabilidades de ocorrência de dias favoráveis para o trabalho mecanizado, utilizando-se informações meteorológicas do município de Santa Maria, RS, Brasil. As condições para se considerar o dia como favorável para o trabalho com máquinas foram a precipitação < 5 mm e o armazenamento de água no solo (ARM entre 40 e 90% da capacidade de água disponível (CAD. O método da cadeia de Markov de primeira ordem foi utilizado para estimar as probabilidades condicionais de dias favoráveis ao trabalho com máquinas. Os resultados indicam que a metodologia aplicada para estimar as probabilidades de dias favoráveis ao uso de máquinas agrícolas foi viável, evidenciando as épocas mais apropriadas à execução de operações agrícolas mecanizadas no campo, para o município de Santa Maria, RS.

  19. Role of the Agr-Like Quorum-Sensing System in Regulating Toxin Production by Clostridium perfringens Type B Strains CN1793 and CN1795

    OpenAIRE

    Chen, Jianming; McClane, Bruce A.

    2012-01-01

    Clostridium perfringens type B causes enteritis and enterotoxemia in domestic animals. By definition, these bacteria must produce alpha toxin (CPA), beta toxin (CPB) and epsilon toxin (ETX) although most type B strains also produce perfringolysin O (PFO) and beta2 toxin (CPB2). A recently identified Agr-like quorum-sensing (QS) system in C. perfringens controls all toxin production by surveyed type A, C, and D strains, but whether this QS is involved in regulating toxin production by type B s...

  20. Comparative analysis of agr groups and virulence genes among subclinical and clinical mastitis Staphylococcus aureus isolates from sheep flocks of the Northeast of Brazil

    Directory of Open Access Journals (Sweden)

    Lara M. de Almeida

    2013-01-01

    Full Text Available Staphylococcus aureus is one of the most frequent mastitis causative agents in small ruminants. The expression of most virulence genes of S. aureus is controlled by an accessory gene regulator (agrlocus. This study aimed to ascertain the prevalence of the different agr groups and to evaluate the occurrence of encoding genes for cytotoxin, adhesins and toxins with superantigen activity in S. aureus isolates from milk of ewes with clinical and subclinical mastitis in sheep flocks raised for meat production The agr groups I and II were identified in both cases of clinical and subclinical mastitis. Neither the arg groups III and IV nor negative agr were found. The presence of cflA gene was identified in 100% of the isolates. The frequency of hla and lukE-D genes was high -77.3 and 82.8%, respectively and all isolates from clinical mastitis presented these genes. The sec gene, either associated to tst gene or not, was identified only in isolates from subclinical mastitis. None of the following genes were identified: bbp, ebpS, cna, fnbB, icaA, icaD, bap, hlg, lukM-lukF-PV and se-a-b-d-e.

  1. Relações contratuais de crédito agrícola e o papel dos agentes financeiros privados: teoria e evidências dos EUA

    Directory of Open Access Journals (Sweden)

    Fabio R Chaddad

    2003-01-01

    Full Text Available Este trabalho analisa a questão do financiamento da produção agrícola sob uma ótica sistêmica, considerando o papel dos agentes privados no fornecimento de crédito rural. Desenvolve-se a idéia de que o volume e o custo de recursos financeiros disponibilizados para a produção agrícola são afetados por "fricções" em diversas transações sequenciais interligando emprestadores e tomadores de crédito. O objetivo do trabalho é analisar as vantagens comparativas dos diversos agentes que atuam no mercado de crédito, enfocando o potencial de cada agente em reduzir as tais fricções. Esta análise comparativa baseia-se na leitura do funcionamento do mercado de crédito agrícola dos Estados Unidos e pode ser aplicada nara o desenvolvimento de novos arranjos contratuais no mercado brasileiro.

  2. Retos del crédito agrícola: estudio de caso de la intermediación financiera en el sur de Sonora, México

    Directory of Open Access Journals (Sweden)

    Mario Alberto Camiro Pérez

    2009-01-01

    Full Text Available En años recientes, la política agrícola oficial ha orientado sus esfuerzos para construir el sistema financiero rural sustentado en un arreglo institucional nuevo. En consecuencia, el Estado mexicano impulsó la creación de la Financiera Rural como banca de desarrollo, y así encaminar sus actividades en torno al crédito agrícola como servicio fundamental del sistema. Asimismo, con el fin de facilitar su transición como banca de segundo piso, se estableció un programa de apoyo a los intermediarios financieros rurales, para mejorar el servicio del crédito agrícola a los productores nacionales. En este contexto, el presente estudio analiza el papel de la Financiera Rural y los retos de la intermediación financiera, con base en un estudio de caso en el valle del Yaqui, Sonora, donde, a pesar de su potencial, las organizaciones de agricultores enfrentan restricciones importantes para acceder a servicios financieros e integrarlos a sus estrategias de desarrollo.

  3. 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

  4. Nuclear reactor repairing device

    International Nuclear Information System (INIS)

    Purpose: To enable free repairing of an arbitrary position in an LMFBR reactor. Constitution: A laser light emitted from a laser oscillator installed out of a nuclear reactor is guided into a portion to be repaired in the reactor by using a reflecting mirror, thereby welding or cutting it. The guidance of the laser out of the reactor into the reactor is performed by an extension tube depending into a through hole of a rotary plug, and the guidance of the laser light into a portion to be repaired is performed by the transmitting and condensing action of the reflecting mirror. (Kamimura, M.)

  5. Fundamentals of reactor chemistry

    International Nuclear Information System (INIS)

    In the Nuclear Engineering School of JAERI, many courses are presented for the people working in and around the nuclear reactors. The curricula of the courses contain also the subject material of chemistry. With reference to the foreign curricula, a plan of educational subject material of chemistry in the Nuclear Engineering School of JAERI was considered, and the fundamental part of reactor chemistry was reviewed in this report. Since the students of the Nuclear Engineering School are not chemists, the knowledge necessary in and around the nuclear reactors was emphasized in order to familiarize the students with the reactor chemistry. The teaching experience of the fundamentals of reactor chemistry is also given. (author)

  6. 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

  7. Generation III+ Reactor Portfolio

    International Nuclear Information System (INIS)

    While the power generation needs of utilities are unique and diverse, they are all faced with the double challenge of meeting growing electricity needs while curbing CO2 emissions. To answer these diverse needs and help tackle this challenge, AREVA has developed several reactor models which are briefly described in this document: The EPRTM Reactor: designed on the basis of the Konvoi (Germany) and N4 (France) reactors, the EPRTM reactor is an evolutionary model designed to achieve best-in-class safety and operational performance levels. The ATMEA1TM reactor: jointly designed by Mitsubishi Heavy Industries and AREVA through ATMEA, their common company. This reactor design benefits from the competencies and expertise of the two mother companies, which have commissioned close to 130 reactor units. The KERENATM reactor: Designed on the basis of the most recent German BWR reactors (Gundremmingen) the KERENATM reactor relies on proven technology while also including innovative, yet thoroughly tested, features. The optimal combination of active and passive safety systems for a boiling water reactor achieves a very low probability of severe accident

  8. The Maple reactor project

    International Nuclear Information System (INIS)

    MDS Nordion supplies the majority of the world's reactor-produced medical isotopes. These isotopes are currently produced in the NRU reactor at AECL's Chalk River Laboratories (CRL). Medical isotopes and related technology are relied upon around the world to prevent, diagnose and treat disease. The NRU reactor, which has played a key role in supplying medical isotopes to date, has been in operation for over 40 years. Replacing this aging reactor has been a priority for MDS Nordion to assure the global nuclear medicine community that Canada will continue to be a dependable supplier of medical isotopes. MDS Nordion contracted AECL to construct two MAPLE reactors dedicated to the production of medical isotopes. The MDS Nordion Medical Isotope Reactor (MMIR) project started in September 1996. This paper describes the MAPLE reactors that AECL has built at its CRL site, and will operate for MDS Nordion. (author)

  9. High temperature reactors

    International Nuclear Information System (INIS)

    With the advent of high temperature reactors, nuclear energy, in addition to producing electricity, has shown enormous potential for the production of alternate transport energy carrier such as hydrogen. High efficiency hydrogen production processes need process heat at temperatures around 1173-1223 K. Bhabha Atomic Research Centre (BARC), is currently developing concepts of high temperature reactors capable of supplying process heat around 1273 K. These reactors would provide energy to facilitate combined production of hydrogen, electricity, and drinking water. Compact high temperature reactor is being developed as a technology demonstrator for associated technologies. Design has been also initiated for a 600 MWth innovative high temperature reactor. High temperature reactor development programme has opened new avenues for research in areas like advanced nuclear fuels, high temperature and corrosion resistant materials and protective coatings, heavy liquid metal coolant technologies, etc. The paper highlights design of these reactors and their material related requirements

  10. 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.

  11. Investigations of the gas-side heat transfer and flow characteristics of steam generators in AGR stations

    International Nuclear Information System (INIS)

    This paper describes the experimental and analytical investigations of the gas-side heat transfer and flow characteristics of steam generators in the AGR stations carried out by CERL. The majority of the experimental work on heat transfer and flow characteristics of close-packed tube arrangements in cross-flow of gases is carried out in a pressurised heat exchanger rig. The rig is operated on-line by a dedicated PDP 11/40 computer over the range of Reynolds number 104 to 3x105. Atmospheric wind tunnels employing either small or large scale models of the specific sections of steam generators are used for a variety of supplementary and development studies. Various measurements techniques and, in particular, LDA and hot wire anemometry employed in these studies are described. The more important aspects of various investigations are illustrated by typical results. In order to ensure the efficient operation and integrity of steam generators under asymmetric boundary conditions a MIX suite of 2-dimensional codes has been developed. The codes calculate the gas and water/steam flow and temperature distributions in each channel of the steam generator taking into account thermal mixing in the gas as it passes through the generator. Application of the MIX codes to the solution of various operational problems is illustrated by typical examples and the continuing exercise of validating the codes against plant operational data is discussed. (author)

  12. Uso de plaguicidas en cultivos agrícolas como herramienta para el monitoreo de peligros en salud

    Directory of Open Access Journals (Sweden)

    Virya Bravo Durán

    2013-03-01

    Full Text Available Costa Rica ha incrementado el uso de plaguicidas de mayor toxicidad, debido entre otras cosas al desarrollo de plagas más resistentes y la necesidad que tienen algunos productos agrícolas de exportación de mantener su posición en el mercado internacional. El ser humano al entrar en contacto con los plaguicidas puede experimentar efectos adversos en su salud desde agudos hasta crónicos que se manifiestan en diferentes grados. Para generar indicadores de peligro en salud en algunos cultivos por el uso de estas sustancias, se utilizaron la cantidad de plaguicidas aplicada y su toxicidad. Los datos de uso se recopilan directamente de los productores, a través de un cuestionario, los ingredientes activos identificados se caracterizaron por su toxicidad y se clasificaron por la manifestación de los efectos. Se calculó como indicador la cantidad de plaguicidas aplicada (kg ia/ha/año por las clases de toxicidad consideradas más peligrosas: 1. Efectos de toxicidad aguda en grado de alto a extremo y 2. Tres o más efectos crónicos positivos. Se recomienda vigilar el uso de bromuro de metilo, metam sodio, terbufos, etoprofos, endosulfan, MCPA y carbofuran por toxicidad aguda de alta a extrema y mancozeb, paraquat, diazinon, 2,4-D y carbofuran por efectos crónicos.  

  13. Biodegradación de diesel mexicano por un consorcio de bacterias de un suelo agrícola

    Directory of Open Access Journals (Sweden)

    Santiago Cardona

    2003-01-01

    Full Text Available Se realiza la biodegradación de diesel presente en agua por medio de microorganismos de un suelo agrícola. Se determina la cinética de biotransformación y adsorción del diesel para su aplicación en los proyectos de saneamiento de suelos y acuíferos contaminados con diesel. Se presenta la metodología y los resultados de la biodegradación y la adsorción del diesel contenido en agua sintética así como la caracterización del suelo de cultivo seleccionado para el estudio. La degradación se realiza utilizando los microorganismos nativos del suelo de cultivo seleccionado, al cual se le suministra nitrógeno como nutriente y sin él. El peróxido de hidrógeno se suministra como fuente de oxígeno. Por último se presentan los análisis de las cinéticas que determinan la volatilización del diesel. Con los resultados obtenidos se determinan las ecuaciones cinéticas de degradación, adsorción y se calcularon las constantes de velocidad.

  14. Violencia laboral contra jornaleras agrícolas en tres comunidades del noroeste de México

    Directory of Open Access Journals (Sweden)

    Ma. del Carmen Arellano Gálvez

    2014-01-01

    Full Text Available El objetivo de este artículo es analizar las formas de violencia laboral contra mujeres jornaleras agrícolas en tres comunidades de Sinaloa, Sonora y Baja California, para lo que se utilizó una metodología cualitativa, a través de entrevistas grupales que se les hicieron a ellas. Los resultados señalan que las trabajadoras reconocen la violación a sus derechos laborales, como no contar con servicios médicos para ellas y sus hijos, ni ingresos por faltar al trabajo cuando éstos enferman y menos opciones laborales durante el embarazo. A diario viven el acoso y el hostigamiento ejercido por hombres posicionados en distintas jerarquías laborales, pero no son pasivas ante la violencia, ya que diseñan estrategias de autocuidado. Otras se organizan para brindar asesoría a mujeres sobre sus derechos laborales y las acompañan en los procesos de denuncia y búsqueda de justicia.

  15. Impactos Ambientais das Atividades Agrícolas em Roraima. = Environmental Impacts of Agriculture Activity in Roraima State.

    Directory of Open Access Journals (Sweden)

    Valdinar Ferreira Melo

    2008-07-01

    Full Text Available A agricultura foi a grande responsável pelo processo de colonização do Brasil. No entanto, estas atividades se desenvolveram ás expensas de ações negativamente impactantes ao meio ambiente. Este trabalho tem com objetivo abordar os impactos ambientais causados pela atividade agrícola no estado de Roraima, despertando o interesse da comunidade para o uso de uma agricultura fundamentada no conceito de sustentabilidade. A prática agropecuária no Brasil, inicialmente de forma empírica, sem muito conhecimento e preocupação com seus efeitos no ambiente, causou a dizimação de grande parte das florestas e a biodiversidade, mas, também, possibilitou a ocupação da terra e a definição dos limites territoriais brasileiros, definindo-se como de grande importância para a sustentação da economia, imprimindo ao Brasil sua vocação agrícola. A atividade nos anos 60 foi concebida para a validação de pacotes tecnológicos importados, contribuiu para a execução de práticas socialmente excludentes e ambientalmente danosas, com reflexos positivos na produção agrícola e comércio de insumos, à custa da implantação de sistemas monoculturais, com motomecanização, irrigação e emprego intensivo de fertilizantes químicos e pesticidas. A impropriedade ambiental deste modelo originou movimentos que culminaram com a conscientização para estas questões, tendo como respostas a elaboração de instrumentos técnicos e jurídicos, e formulação de propostas para avaliar e mitigar os impactos ambientais e modificar as ações humanas, tornando-as mais condizentes com novos paradigmas da sociedade. Em Roraima, esta atividade sofre uma nova mudança, onde as técnicas primitivas de exploração agrícola começam a ser substituídas por atividades tecnificadas com o uso intensivo de tecnologias, com risco de improbidade ambiental que pode culminar com a degradação do meio, caso não haja uma perícia profunda das caracter

  16. Los Objetos de Aprendizaje en la carrera de Ingeniería Agrícola: modalidad semipresencial

    Directory of Open Access Journals (Sweden)

    Nelson Nápoles Hernández

    2011-01-01

    Full Text Available De las innovaciones tecnológicas más significativas de los últimos años, sin duda Internet tiene el potencial de producir un cambio de paradigma en el modo en el que las personas se educan. Por ello, repercute en el modo en que se deben, preparar los materiales educativos para ponerlos a disposición en la comunidad universitaria. En la actualidad se comienza a vislumbrar que los Objetos de Aprendizajes (OA son especialmente atractivos para el mundo digital y por ende para la educación virtual. De ahí su importancia en las carreras agropecuarias cubanas especialmente en la de Ingeniería Agrícola, teniendo en cuenta los nuevos retos de la Nueva Universidad Cubana. Las exigencias en la elaboración de OA , permitirá que los contenidos que se elaboren para dicha carrera puedan soportarse correctamente en correspondencia con los estándares establecidos internacionalmente y estos puedan ser catalogados, clasificados e indizados sin dificultad alguna.

  17. Reactor Safety: Introduction

    International Nuclear Information System (INIS)

    The programme of the Reactor Safety Division focuses on the development of expertise on materials behaviour under irradiation for fission and fusion oriented applications. Furthermore, as nuclear energy needs international public acceptance with respect to safety and efficient management of natural resources and wants to reduce the burden of nuclear waste, the Reactor Safety Division enhanced its efforts to develop the MYRRHA project. MYRRHA, an accelerator driven sub-critical system, might have the potential to cope in Europe with the above mentioned constraints on acceptability and might serve as a technological platform for GEN IV reactor development, in particular the Liquid Metal Fast Reactor.The Reactor Safety Division gathers three research entities that are internationally recognised: the Reactor Materials Research department, the Reactor Physics and MYRRHA department and the Instrumentation department.The objectives of Reactor Materials Research are: to evaluate the integrity and behaviour of structural materials and nuclear fuels used in present and future nuclear power industry; to perform research to unravel and understand the parameters that determine the material and fuel behaviour under or after irradiation; to contribute to the interpretation and modelling of the materials and fuels behaviour in order to develop and assess strategies for optimum life management of nuclear power plant components. The programmes within the Reactor Materials Research department concentrate on four distinct disciplines: Reactor Pressure Vessel Steel embrittlement Stress corrosion cracking in reactor coolant environment, including Irradiation Assisted Stress Corrosion Cracking; Nuclear Fuel characterisation and development of new fuel types for commercial and test reactors. Development of materials for Fusion and advanced nuclear fission reactors. The safe operation of present nuclear power plants relies primarily on the integrity of the reactor pressure vessel

  18. Simulación fluido-térmica de un reactor de gasificación de lecho fijo descendente

    OpenAIRE

    Felisart Serlavóss, Bernat

    2013-01-01

    El proyecto consta de un estudio preliminar de las tecnologías de gasificación existentes y un posterior análisis de los procesos de gasificación en los reactores de lecho fijo con flujo descendente a equicorriente (downdraft) como son la pirolisis, oxidación del combustible y reducción de los gases creados. Se estudian las fuentes renovables posibles como combustible para su uso en la gasificación, se centra en los residuos agrícolas provenientes del maíz como son su coronta y sus cañas, ...

  19. Research reactors in Argentina

    International Nuclear Information System (INIS)

    Argentine Nuclear Development started in early fifties. In 1957, it was decided to built the first a research reactor. RA-1 reactor (120 kw, today licensed to work at 40 kW) started operation in January 1958. Originally RA-1 was an Argonaut (American design) reactor. In early sixties, the RA-1 core was changed. Fuel rods (20% enrichment) was introduced instead the old Argonaut core design. For that reason, a critical facility named RA-0 was built. After that, the RA-3 project started, to build a multipurpose 5 MW nuclear reactor MTR pool type, to produce radioisotopes and research. For that reason and to define the characteristics of the RA-3 core, another critical facility was built, RA-2. Initially RA-3 was a 90 % enriched fuel reactor, and started operation in 1967. When Atucha I NPP project started, a German design Power Reactor, a small homogeneous reactor was donated by the German Government to Argentina (1969). This was RA-4 reactor (20% enrichment, 1W). In 1982, RA-6 pool reactor achieved criticality. This is a 500 kW reactor with 90% enriched MTR fuel elements. In 1990, RA-3 started to operate fueled by 20% enriched fuel. In 1997, the RA-8 (multipurpose critical facility located at Pilcaniyeu) started to operate. RA-3 reactor is the most important CNEA reactor for Argentine Research Reactors development. It is the first in a succession of Argentine MTR reactors built by CNEA (and INVAP SE ) in Argentina and other countries: RA-6 (500 kW, Bariloche-Argentina), RP-10 (10MW, Peru), NUR (500 kW, Algeria), MPR (22 MW, Egypt). The experience of Argentinian industry permits to compete with foreign developed countries as supplier of research reactors. Today, CNEA has six research reactors whose activities have a range from education and promotion of nuclear activity, to radioisotope production. For more than forty years, Argentine Research Reactors are working. The experience of Argentine is important, and argentine firms are able to compete in the design and

  20. Considerations on the design of a helium circulator for a high temperature modular reactor system

    International Nuclear Information System (INIS)

    A modular helium cooled, high temperature reactor system with a thermal output of 200 MW per reactor has been developed by the KWU group for cogeneration of electricity and process steam. The flow of the reactor coolant - Helium at 60 bars and 250/700 deg. C is maintained by one circulator per reactor. The circulator is driven by a variable speed Siemens asynchronous motor and is submerged in the helium primary system. For operational reasons high reliability and availability of the circulator is required. The operational requirements for the circulator design are presented in this paper. The actual design has been carried out in close cooperation with the designer and manufacturer of all submerged circulators operating in AGR plants in Great Britain, James Howden Co. Renfrew, Scotland. Design solutions received so far and mainly based on sufficiently proven components - such as oil bath lubricated bearing systems - will be described. Special attention will be paid on the necessary test work; especially for the prototype to confirm the lay out. (author). 9 figs

  1. Thai research reactor

    International Nuclear Information System (INIS)

    The Office of Atomic Energy for Peace (OAEP) was established in 1962, as a reactor center, by the virtue of the Atomic Energy for Peace Act, under operational policy and authority of the Thai Atomic Energy for Peace Commission (TAEPC); and under administration of Ministry of Science, Technology and Energy. It owns and operates the only Thai Research Reactor (TRR-1/M1). The TRR-1/M1 is a mixed reactor system constituting of the old MTR type swimming pool, irradiation facilities and cooling system; and TRIGA Mark III core and control instrumentation. The general performance of TRR-1/M1 is summarized in Table I. The safe operation of TRR-1/M1 is regulated by Reactor Safety Committee (RSC), established under TAEPC, and Health Physics Group of OAEP. The RCS has responsibility and duty to review of and make recommendations on Reactor Standing Orders, Reactor Operation Procedures, Reactor Core Loading and Requests for Reactor Experiments. In addition,there also exist of Emergency Procedures which is administered by OAEP. The Reactor Operation Procedures constitute of reactor operating procedures, system operating procedures and reactor maintenance procedures. At the level of reactor routine operating procedures, there is a set of Specifications on Safety and Operation Limits and Code of Practice from which reactor shift supervisor and operators must follow in order to assure the safe operation of TRR-1/M1. Table II is the summary of such specifications. The OAEP is now upgrading certain major components of the TRR-1/M1 such as the cooling system, the ventilation system and monitoring equipment to ensure their adequately safe and reliable performance under normal and emergency conditions. Furthermore, the International Atomic Energy Agency has been providing assistance in areas of operation and maintenance and safety analysis. (author)

  2. Nuclear Reactor Physics

    Science.gov (United States)

    Stacey, Weston M.

    2001-02-01

    An authoritative textbook and up-to-date professional's guide to basic and advanced principles and practices Nuclear reactors now account for a significant portion of the electrical power generated worldwide. At the same time, the past few decades have seen an ever-increasing number of industrial, medical, military, and research applications for nuclear reactors. Nuclear reactor physics is the core discipline of nuclear engineering, and as the first comprehensive textbook and reference on basic and advanced nuclear reactor physics to appear in a quarter century, this book fills a large gap in the professional literature. Nuclear Reactor Physics is a textbook for students new to the subject, for others who need a basic understanding of how nuclear reactors work, as well as for those who are, or wish to become, specialists in nuclear reactor physics and reactor physics computations. It is also a valuable resource for engineers responsible for the operation of nuclear reactors. Dr. Weston Stacey begins with clear presentations of the basic physical principles, nuclear data, and computational methodology needed to understand both the static and dynamic behaviors of nuclear reactors. This is followed by in-depth discussions of advanced concepts, including extensive treatment of neutron transport computational methods. As an aid to comprehension and quick mastery of computational skills, he provides numerous examples illustrating step-by-step procedures for performing the calculations described and chapter-end problems. Nuclear Reactor Physics is a useful textbook and working reference. It is an excellent self-teaching guide for research scientists, engineers, and technicians involved in industrial, research, and military applications of nuclear reactors, as well as government regulators who wish to increase their understanding of nuclear reactors.

  3. Precaución, riesgo y sostenibilidad en los organismos agrícolas modificados genéticamente Precaución, riesgo y sostenibilidad en los organismos agrícolas modificados genéticamente

    Directory of Open Access Journals (Sweden)

    J. David Tábara

    2003-01-01

    Full Text Available El cultivo y la comercialización de Organismos Agrícolas Modificados Genéticamente (0MG es origen de multitud de importantes polémicas sociales, económicos y ecológicas, en cuya resolución a menudo se reclama la incorporación del principio y de prácticas de precaución. Este artículo introduce y analiza algunas de estas discusiones a partir de la perspectiva aportada por el proyecto europeo Precautionary Expertise for GM Crops (PEG sobre la aplicación de la precaución en el desarrollo y la comercialización de OMG agrícolas. A partir del material recogido en el caso español, los autores argumentan que gran parte de los desacuerdos que surgen de en la interpretación y aplicación de la precaución con relación a los OMG derivan de la adopción de una perspectiva más o menos reduccionista, o más o menos sistémica, tanto en la evaluación y regulación de los riesgos como en la bondad, los costes o los beneficios de su utilización. Por ello es posible detectar analíticamente, paro el caso español, una clara oposición entre aquellas interpretaciones de la precaución caso por caso, de aquellas que sostienen la necesidad de aplicar prácticas de evaluación y de gestión basadas en una precaución sistémica, más cercano a los principios y los postulados políticos de la sostenibilidad.The debate over GMO crops and their commercialisation becomes the source of a large number of conflicts with important social, economic and ecologic consequences the resolution of which often calls for the application of a precautionary approach and of the precautionary principle. This article introduces and analyses such discussions, and does so within the framework provided by the EU project Precautionary Expertise for GM (PEG. Based on first material gathered for the Spanish case study, the authors argue that a large majority of the disagreements around practical application of precaution over agricultural GMO in Spain come from a conception

  4. Reactor containment and reactor safety in the United States

    International Nuclear Information System (INIS)

    The reactor safety systems of two reactors are studied aiming at the reactor containment integrity. The first is a BWR type reactor and is called Peachbottom 2, and the second is a PWR type reactor, and is called surry. (E.G.)

  5. TRIGA reactor main systems

    International Nuclear Information System (INIS)

    This module describes the main systems of low power (<2 MW) and higher power (≥2 MW) TRIGA reactors. The most significant difference between the two is that forced reactor cooling and an emergency core cooling system are generally required for the higher power TRIGA reactors. However, those TRIGA reactors that are designed to be operated above 3 MW also use a TRIGA fuel that is specifically designed for those higher power outputs (3 to 14 MW). Typical values are given for the respective systems although each TRIGA facility will have unique characteristics that may only be determined by the experienced facility operators. Due to the inherent wide scope of these research reactor facilities construction and missions, this training module covers those systems found at most operating TRIGA reactor facilities but may also discuss non-standard equipment that was found to be operationally useful although not necessarily required. (author)

  6. Evaluation of research reactors

    International Nuclear Information System (INIS)

    The present status of research reactors with highly enriched (93%) uranium fuel at JAERI, JRR-2 and JMTR is described. JRR-2 is a heterogeneous type of reactor, using heavy water as moderator and coolant. It uses both MTR type and cylindrical type of fuel elements. The maximum thermal power and the thermal neutron flux are 10 MW and 2x1014 n/cm2 see respectively. The reactor has been used for various experiments such as solid state physics, material irradiation, reactor fuel irradiation and radioisotope production. The JMTR is a multi-purpose tank type material testing reactor, and light water moderator and coolant, operated at 50 MW. The evaluation of lower enriched fuel and its consequences for both reactors is considered more especially

  7. Multipurpose research reactors

    International Nuclear Information System (INIS)

    The international symposium on the utilization of multipurpose research reactors and related international co-operation was organized by the IAEA to provide for information exchange on current uses of research reactors and international co-operative projects. The symposium was attended by about 140 participants from 36 countries and two international organizations. There were 49 oral presentations of papers and 24 poster presentations. The presentations were divided into 7 sessions devoted to the following topics: neutron beam research and applications of neutron scattering (6 papers and 1 poster), reactor engineering (6 papers and 5 posters), irradiation testing of fuel and material for fission and fusion reactors (6 papers and 10 posters), research reactor utilization programmes (13 papers and 4 posters), neutron capture therapy (4 papers), neutron activation analysis (3 papers and 4 posters), application of small reactors in research and training (11 papers). A separate abstract was prepared for each of these papers. Refs, figs and tabs

  8. The nuclear soliton reactor

    International Nuclear Information System (INIS)

    The basic reactor physics of a completely novel nuclear fission reactor design - the soliton-reactor - is presented on the basis of a simple model. In such a reactor, the neutrons in the critical region convert either fertile material in the adjacent layers into fissile material or reduce the poisoning of fissile material in such a manner that successively new critical regions emerge. The result is an autocatalytically driven burn-up wave which propagates throughout the reactor. Thereby, the relevant characteristic spatial distributions (neutron flux, specific power density and the associated particle densities) are solitons - wave phenomena resulting from non-linear partial differential equations which do not change their shape during propagation. A qualitativley new kind of harnessing nuclear fission energy may become possible with fuel residence times comparable with the useful lifetime of the reactor system. In the long run, fast breeder systems which exploit the natural uranium and thorium resources, without any reprocessing capacity are imaginable. (orig.)

  9. 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...

  10. Fusion reactor research

    International Nuclear Information System (INIS)

    This work covers four separate areas: (1) development of technology for processing liquid lithium from blankets, (2) investigation of hydrogen isotope permeation in candidate structural metals and alloys for near-term fusion reactors, (3) analytical studies encompassing fusion reactor thermal hydraulics, tritium facility design, and fusion reactor safety, and (4) studies involving dosimetry and damage analysis. Recent accomplishments in each of these areas are summarized

  11. The Integral Fast Reactor

    International Nuclear Information System (INIS)

    The Integral Fast Reactor (IFR) is an innovative liquid metal reactor concept being developed at Argonne National Laboratory. It seeks to specifically exploit the inherent properties of liquid metal cooling and metallic fuel in a way that leads to substantial improvements in the characteristics of the complete reactor system. This paper describes the key features and potential advantages of the IFR concept, with emphasis on its safety characteristics. 3 refs., 4 figs., 1 tab

  12. The replacement research reactor

    International Nuclear Information System (INIS)

    As a consequences of the government decision in September 1997. ANSTO established a replacement research reactor project to manage the procurement of the replacement reactor through the necessary approval, tendering and contract management stages This paper provides an update of the status of the project including the completion of the Environmental Impact Statement. Prequalification and Public Works Committee processes. The aims of the project, management organisation, reactor type and expected capabilities are also described

  13. PFBR reactor protection

    International Nuclear Information System (INIS)

    Design philosophy adopted for Prototype Fast breeder Reactor (PFBR) is a classical one and has the following features: triplicated sensors for measuring important safety parameters; two independent reactor protection Logic Systems based on solid state devices; reactivity control achieved by control rods; gas equipped modules at the core blanket interface providing negative reactivity. Design verification of these features showed that safety of the reactor can be achieved by a traditional approach since the inherent features of LMFBR make this easy

  14. Reactor BR2

    International Nuclear Information System (INIS)

    The BR2 reactor is still SCK-CEN's most important nuclear facility. After an extensive refurbishment to compensate for the ageing of the installation, the reactor was restarted in April 1997. Various aspects concerning the operation of the BR2 Reactor, the utilisation of the CALLISTO loop and the irradiation programme, the BR2 R and D programme and the production of isotopes and of NTD-silicon are discussed. Progress and achievements in 1999 are reported

  15. TRIGA reactor characteristics

    International Nuclear Information System (INIS)

    This module describes the general design, characteristics and parameters of TRIGA reactors and fuels. It is recommended that most of this information should be incorporated into any reactor operator training program and, in many cases, the facility Safety Analysis Report. It is oriented to teach the basics of the physics and mechanical design of the TRIGA fuel as well as its unique operational characteristics and the differences between TRIGA fuels and others more traditional reactor fuels. (nevyjel)

  16. Reactor Safety Analysis

    International Nuclear Information System (INIS)

    The objective of SCK-CEN's programme on reactor safety is to develop expertise in probabilistic and deterministic reactor safety analysis. The research programme consists of four main activities, in particular the development of software for reliability analysis of large systems and participation in the international PHEBUS-FP programme for severe accidents, the development of an expert system for the aid to diagnosis; the development and application of a probabilistic reactor dynamics method. Main achievements in 1999 are reported

  17. Reactor Engineering Department annual report

    International Nuclear Information System (INIS)

    Research and development activities in the Department of Reactor Engineering in fiscal 1984 are described. The work of the Department is closely related to development of multipurpose Very High Temperature Gas Cooled Reactor and Fusion Reactor, and development of Liquid Metal Fast Breeder Reactor carried out by Power Reactor and Nuclear Fuel Development Corporation. Contents of the report are achievements in fields such as nuclear data and group constants, theoretical method and code development, reactor physics experiment and analysis, fusion neutronics, shielding, reactor and nuclear instrumentation, reactor control and diagnosis, safeguards technology, and activities of the Committee on Reactor Physics. (author)

  18. Reactor Engineering Division annual report

    International Nuclear Information System (INIS)

    Research and development activities in the Division of Reactor Engineering in fiscal 1981 are described. The work of the Division is closely related to development of multipurpose Very High Temperature Gas Cooled Reactor and fusion reactor, and development of Liquid Metal Fast Breeder Reactor carried out by Power Reactor and Nuclear Fuel Development Corporation. Contents of the report are achievements in fields such as nuclear data and group constants, theoretical method and code development, integral experiment and analysis, shielding, reactor and nuclear instrumentation, reactor control and diagnosis, and fusion reactor technology, and activities of the Committee on Reactor Physics. (author)

  19. Reactor Engineering Division annual report

    International Nuclear Information System (INIS)

    Research activities in the Division of Reactor Engineering in fiscal 1979 are described. The work of the Division is closely related to development of multi-purpose Very High Temperature Gas Cooled Reactor and fusion reactor, and development of Liquid Metal Fast Breeder Reactor carried out by Power Reactor and Nuclear Fuel Development Corporation. Contents of the report are achievements in fields such as nuclear data and group constants, theoretical method and code development, integral experiment and analysis, shielding, reactor and nuclear instrumentation, reactor control and diagnosis, and fusion reactor technology, and activities of the Committees on Reactor Physics and on Decomissioning of Nuclear Facilities. (author)

  20. New reactor concepts

    International Nuclear Information System (INIS)

    The document gives a summary of new nuclear reactor concepts from a technological point of view. Belgium supports the development of the European Pressurized-Water Reactor, which is an evolutionary concept based on the European experience in Pressurized-Water Reactors. A reorientation of the Belgian choice for this evolutionary concept may be required in case that a decision is taken to burn plutonium, when the need for flexible nuclear power plants arises or when new reactor concepts can demonstrate proved benefits in terms of safety and cost

  1. Reactor construction steels

    International Nuclear Information System (INIS)

    The basic functions of light water reactor components are shown on the example of a pressurized water reactor and the requirements resulting therefrom for steel, the basic structural material, are derived. A detailed analysis of three main groups of reactor steels is presented and the applications are indicated of low-alloyed steels, high-alloyed austenitic steels, and steels with a high content of Ni and of alloying additions for steam generator pipes. An outline is given of prospective fast breeder reactor steels. (J.K.)

  2. Commercialization of fast reactors

    International Nuclear Information System (INIS)

    Comparative analysis has been performed of capital and fuel cycle costs for fast BN-type and pressurized light water VVER-type reactors. As a result of materials demand and components costs comparison of NPPs with VVER-1000 and BN-600 reactors, respectively, conclusion was made, that under equal conditions of the comparison, NPP with fast reactor had surpassed the specific capital cost of NPP with VVER by about 30 - 40 %. Ways were determined for further decrease of this difference, as well as for the fuel cycle cost reduction, because at present it is higher than that of VVER-type reactors. (author)

  3. Mirror fusion reactors

    International Nuclear Information System (INIS)

    Conceptual design studies were made of fusion reactors based on the three current mirror-confinement concepts: the standard mirror, the tandem mirror, and the field-reversed mirror. Recent studies of the standard mirror have emphasized its potential as a fusion-fission hybrid reactor, designed to produce fuel for fission reactors. We have designed a large commercial hybrid and a small pilot-plant hybrid based on standard mirror confinement. Tandem mirror designs include a commercial 1000-MWe fusion power plant and a nearer term tandem mirror hybrid. Field-reversed mirror designs include a multicell commercial reactor producing 75 MWe and a single-cell pilot plant

  4. Natural convection type reactor

    International Nuclear Information System (INIS)

    In a natural convection type nuclear reactor, a reactor core is disposed such that the top of the reactor core is always situated in a flooded position even if pipelines connected to the pressure vessel are ruptured and the level at the inside of the reactor vessel is reduced due to flashing. Further, a lower dry well situated below the pressure vessel is disposed such that it is in communication with a through hole to a pressure suppression chamber situated therearound and the reactor core is situated at the level lower than that of the through hole. If pipelines connected to the pressure vessel are ruptured to cause loss of water, although the water level is lowered after the end of the flashing, the reactor core is always flooded till the operation of a pressure accummulation water injection system to prevent the top of the reactor core even from temporary exposure. Further, injected water is discharged to the outside of the pressure vessel, transferred to the lower dry well, and flows through the through hole to the pressure control chamber and cools the surface of the reactor pressure vessel from the outside. Accordingly, the reactor core is cooled to surely and efficiently remove the after-heat. (N.H.)

  5. INVAP's Research Reactor Designs

    International Nuclear Information System (INIS)

    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 IAEA safety

  6. Reactor power control device

    International Nuclear Information System (INIS)

    The present invention provides a control device which can conduct scram and avoid lowering of the power of a nuclear power plant upon occurrence of earthquakes. Namely, the device of the present invention comprises, in addition to an existent power control device, (1) an earthquake detector for detecting occurrence and annihilation of earthquakes and (2) a reactor control device for outputting control rod operation signals and reactor core flow rate control signals depending on the earthquake detection signals from the detector, and reactor and plant information. With such a constitution, although the reactor is vibrated by earthquakes, the detector detects slight oscillations of the reactor by initial fine vibration waves as premonitory symptoms of serious earthquakes. The earthquake occurrence signals are outputted to the reactor control device. The reactor control device, receiving the signals, changes the position of control rods by way of control rod driving mechanisms to make the axial power distribution in the reactor core to a top peak type. As a result, even if the void amount in the reactor core is reduced by the subsequent actual earthquakes, since the void amount is moved, effects on the increase of neutron fluxes by the actual earthquakes is small. (I.S.)

  7. Nuclear reactor internals arrangement

    International Nuclear Information System (INIS)

    A nuclear reactor internals arrangement is disclosed which facilitates reactor refueling. A reactor vessel and a nuclear core is utilized in conjunction with an upper core support arrangement having means for storing withdrawn control rods therein. The upper core support is mounted to the underside of the reactor vessel closure head so that upon withdrawal of the control rods into the upper core support, the closure head, the upper core support and the control rods are removed as a single unit thereby directly exposing the core for purposes of refueling

  8. Fusion Reactor Materials

    International Nuclear Information System (INIS)

    The objective of SCK-CEN's programme on fusion reactor materials is to contribute to the knowledge on the radiation-induced behaviour of fusion reactor materials and components as well as to help the international community in building the scientific and technical basis needed for the construction of the future reactor. Ongoing projects include: the study of the mechanical and chemical (corrosion) behaviour of structural materials under neutron irradiation and water coolant environment; the investigation of the characteristics of irradiated first wall material such as beryllium; investigations on the management of materials resulting from the dismantling of fusion reactors including waste disposal. Progress and achievements in these areas in 2001 are discussed

  9. Vantagem comparativa dinâmica e crescimento numa economia com dois setores: agrícola e industrial

    Directory of Open Access Journals (Sweden)

    Emerson Marinho

    2007-12-01

    Full Text Available Este artigo analisa os efeitos dos ganhos de produtividade na agricultura sobre o processo de industrialização e, conseqüentemente, sobre o crescimento de longo prazo da economia. Supõe-se no modelo que a produtividade na agricultura é endógena e que a experiência acumulada na indústria exerça impacto positivo sobre a produtividade agrícola. Uma condição necessária para o declínio do emprego industrial é que, devido à vantagem comparativa na agricultura, a economia do resto do mundo apresente baixa integração agricultura/indústria Mostra-se ainda sob que condições intervenções de política podem reverter o padrão de especialização induzido pela vantagem comparativa inicial e ainda assim obter ganhos de bem estar.This paper analyses the effects of agricultural productivity gains on the industrialization process and on the long run growth rate of the economy. The model allows endogenous gains in agricultural productivity and, besides that, it is assumed that accumulated experience in the manufacture sector exerts a positive impact on agricultural productivity. The model shown that a necessary condition to the decline of industrial employment, due to comparative advantage in agriculture, is that the economy of the rest of world has poor industry/ agriculture integration. Finally, it is also shown that interventionist can reverse specialization induced by initial comparative advantages.

  10. Torque nos rodados motrizes de um trator agrícola submetido a ensaios de tração

    Directory of Open Access Journals (Sweden)

    Diego A. Fiorese

    2015-09-01

    Full Text Available RESUMOA determinação do torque nos rodados motrizes dos tratores agrícolas complementa os ensaios de tração e permite o cálculo da distribuição dos esforços tratórios entre os eixos. O objetivo principal desta pesquisa foi determinar a demanda de torque nos rodados motrizes de um trator com potência do motor de 89 kW, buscando avaliar o torque demandado em função da utilização da tração dianteira assistida (TDA, para distintas marchas e conforme aumento da força de tração. Foram realizados ensaios de tração sobre pista de concreto utilizando-se um torciômetro instalado no eixo traseiro do trator, um carro dinamométrico e instrumentação eletrônica para aquisição de dados. Avaliaram-se a TDA ligada e desligada, quatro marchas (5, 7, 8 e 9 km h-1 e oito cargas na barra de tração (4, 8, 12, 16, 20, 24, 28, 30 kN. Os resultados analisados estatisticamente através de equações de regressão indicaram comportamento similar para todas as marchas sendo que, conforme o aumento da força de tração ocorreu crescimento linear da demanda de torque nos eixos motrizes. Com a TDA ligada nas cargas mais baixas o torque é maior no eixo dianteiro e nas cargas mais altas é maior no eixo traseiro.

  11. First high temperature safety tests of AGR-1 TRISO fuel with the Fuel Accident Condition Simulator (FACS) furnace

    International Nuclear Information System (INIS)

    Three TRISO fuel compacts from the AGR-1 irradiation experiment were subjected to safety tests at 1600 and 1800 °C for approximately 300 h to evaluate the fission product retention characteristics. Silver behavior was dominated by rapid release of an appreciable fraction of the compact inventory (3—34%) at the beginning of the tests, believed to be from inventory residing in the compact matrix and outer pyrocarbon (OPyC) prior to the safety test. Measurable release of silver from intact particles appears to become apparent only after ~60 h at 1800 °C. The release rate for europium and strontium was nearly constant for 300 h at 1600 °C (reaching maximum values of approximately 2x10-3 and 8x10-4 respectively), and at this temperature the release may be mostly limited to inventory in the compact matrix and OPyC prior to the safety test. The release rate for both elements increased after approximately 120 h at 1800 °C, possibly indicating additional measurable release through the intact particle coatings. Cesium fractional release from particles with intact coatings was <10-6 after 300 h at 1600 °C or 100 h at 1800 °C, but release from the rare particles that experienced SiC failure during the test could be significant. However, Kr release was still very low for 300 h 1600 °C (<2x10-6). At 1800 °C, krypton release increased noticeably after SiC failure, reflecting transport through the intact outer pyrocarbon layer. Nonetheless, the krypton and cesium release fractions remained less than approximately 10-3 after 277 h at 1800 °C.

  12. First high temperature safety tests of AGR-1 TRISO fuel with the Fuel Accident Condition Simulator (FACS) furnace

    Energy Technology Data Exchange (ETDEWEB)

    Demkowicz, Paul A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Reber, Edward L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Scates, Dawn M. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Scott, Les [Idaho National Lab. (INL), Idaho Falls, ID (United States); Collin, Blaise P. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    Three TRISO fuel compacts from the AGR-1 irradiation experiment were subjected to safety tests at 1600 and 1800 °C for approximately 300 h to evaluate the fission product retention characteristics. Silver behavior was dominated by rapid release of an appreciable fraction of the compact inventory (3–34%) at the beginning of the tests, believed to be from inventory residing in the compact matrix and outer pyrocarbon (OPyC) prior to the safety test. Measurable release of silver from intact particles appears to become apparent only after ~60 h at 1800 °C. The release rate for europium and strontium was nearly constant for 300 h at 1600 °C (reaching maximum values of approximately 2×10⁻³ and 8×10⁻⁴ respectively), and at this temperature the release may be mostly limited to inventory in the compact matrix and OPyC prior to the safety test. The release rate for both elements increased after approximately 120 h at 1800 °C, possibly indicating additional measurable release through the intact particle coatings. Cesium fractional release from particles with intact coatings was <10⁻⁶ after 300 h at 1600 °C or 100 h at 1800 °C, but release from the rare particles that experienced SiC failure during the test could be significant. However, Kr release was still very low for 300 h 1600 °C (<2 × 10⁻⁶). At 1800 °C, krypton release increased noticeably after SiC failure, reflecting transport through the intact outer pyrocarbon layer. Nonetheless, the krypton and cesium release fractions remained less than approximately 10⁻³ after 277 h at 1800 °C.

  13. First high temperature safety tests of AGR-1 TRISO fuel with the Fuel Accident Condition Simulator (FACS) furnace

    Science.gov (United States)

    Demkowicz, Paul A.; Reber, Edward L.; Scates, Dawn M.; Scott, Les; Collin, Blaise P.

    2015-09-01

    Three TRISO fuel compacts from the AGR-1 irradiation experiment were subjected to safety tests at 1600 and 1800 °C for approximately 300 h to evaluate the fission product retention characteristics. Silver behavior was dominated by rapid release of an appreciable fraction of the compact inventory (3-34%) at the beginning of the tests, believed to be from inventory residing in the compact matrix and outer pyrocarbon (OPyC) prior to the safety test. Measurable release of silver from intact particles appears to become apparent only after ∼60 h at 1800 °C. The release rate for europium and strontium was nearly constant for 300 h at 1600 °C (reaching maximum values of approximately 2 × 10-3 and 8 × 10-4 respectively), and at this temperature the release may be mostly limited to inventory in the compact matrix and OPyC prior to the safety test. The release rate for both elements increased after approximately 120 h at 1800 °C, possibly indicating additional measurable release through the intact particle coatings. Cesium fractional release from particles with intact coatings was release from the rare particles that experienced SiC failure during the test could be significant. However, Kr release was still very low for 300 h 1600 °C (release increased noticeably after SiC failure, reflecting transport through the intact outer pyrocarbon layer. Nonetheless, the krypton and cesium release fractions remained less than approximately 10-3 after 277 h at 1800 °C.

  14. Las técnicas geomáticas aplicadas en la agricultura: El catastro agrícola

    Directory of Open Access Journals (Sweden)

    Dámaso R. Ponvert Delisles

    2012-01-01

    Full Text Available Las técnicas Geomáticas, Geoinformáticas o de Geoinformación, como se prefiera nombrarlas, son un conjunto de tecnologías geoespaciales así como programas informáticos especializados para el análisis de los datos y su representación espacial. Entre las más importantes, destacan la Teledetección, los Sistemas de Información Geográfica (SIG, los Sistemas de Posicionamiento Global (GPS y la Cartografía, así como software para el procesamiento digital y representación CAD entre otros. Hoy en día sería casi imposible gestionar los procesos agrarios sin recurrir al empleo de alguna de estas técnicas. Una de las herramientas cartográficas temáticas fundamentales son los mapas catastrales, definidos como documentos cartográficos que representan los bienes inmuebles de un área agrícola con suficiente detalle espacial para facilitar la gestión a nivel de parcelas, sub-parcelas e incluso a escala intraparcelaria. Precisamente el trabajo tiene como objetivo demostrar la necesidad e importancia del empleo de las herramientas catastrales para lograr una gestión agraria y territorial eficiente. Para ello se hace analiza el avance del catastro como sistema en Cuba, llegando a la concepción contemporánea y se particulariza en los catastros especializados para el sector, mostrando un ejemplo concreto que permite a los directivos y especialistas de las PyMES apreciar sus bondades.

  15. The development of direct core monitoring in Nuclear Electric plc

    International Nuclear Information System (INIS)

    Monitoring of graphite behaviour in Nuclear Electric Magnox and AGR reactors is necessary to support operating safety cases and to ensure that reactor operation is optimized to sustain the necessary core integrity for the economic life of the reactors. The monitoring programme combines studies for pre-characterized ''installed'' samples with studies on samples trepanned from within the cores and also with studies of core and channel geometry using specially designed equipment. Nuclear Electric has two trepanning machines originally designed for Magnox-reactor work which have been used for a substantial programme over many years. They have recently been upgraded to improve sampling speed, safety and versatility - the last being demonstrated by their adaptation for a recently-won contract associated with decommissioning the Windscale piles. Radiological hazards perceived when the AGR trepanning system was designed resulted in very cumbersome equipment. This has worked well but has been inconvenient in operation. The development of a smaller and improved system for deploying the equipment is now reported. Channel dimension monitoring equipment is discussed in detail with examples of data recovered from both Magnox and AGR cores. A resolution of ± 2 of arc (tilt) and ± 0.01 mm change in diameter in attainable. It is also theoretically possible to establish brick stresses by measuring geometry changes which result from trepanning. Current development work on a revolving scanning laser rangefinder which will enable the measurement of diameters to a resolution of 0.001 mm will also be discussed. This paper also discusses non-destructive techniques for crack detection employing ultrasound or resistance networks, the use of special manipulators to deliver inspection and repair equipment and recent developments to install displacement monitors in peripheral regions of the cores, to aid the understanding of the interaction of the restraint system with the core - the region

  16. The research reactors their contribution to the reactors physics

    International Nuclear Information System (INIS)

    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.)

  17. A study on implementation of dynamic safety system in programmable logic controller for pressurized water reactor

    International Nuclear Information System (INIS)

    The dynamic safety system (DSS) is a computer based reactor protection system that has dynamic self-testing feature and fail-safe nature inherently. The inherent dynamic self-testing feature and fail-safe design provide a high level of reliability and low spurious trip rate. We can also reduce the time and human efforts to maintain the system by virtue of those features. Therefore, the application of the DSS to PWR has many advantages. The DSS has been applied only to advanced gas-cooled reactor (AGR) in the UK. In order to apply the DSS for PWR, the DSS has to be modified because there exist many differences between PWR and AGR for which the DSS was tested and installed. These differences are trip algorithms, monitored parameters, trip logics, and other conditions. In this study, the DSS algorithm is modified for PWR first. The modified DSS has several new features : 1) The modified DSS tests and processes time-dependent parameters, while the original DSS does not. 2) It has flexibility for handling several types of voting logic but the original DSS handles the only one type of voting - 2 out of 4 coincidence logic. Then, in this study, the modified DSS is implemented in programmable logic controller (PLC) using the ladder logic. Finally, the modified DSS is tested in two ways in this work : 1) The manual test is performed using direct input through the human computer interface (HCI) system. 2) The scenario based test is performed using input from the FISA-2/WS simulator. From the test results, it is shown that the modified DSS operates correctly in all conditions

  18. One piece reactor removal

    International Nuclear Information System (INIS)

    Japan Research Reactor No.3 (JRR-3) was the first reactor consisting of 'Japanese-made' components alone except for fuel and heavy water. After reaching its initial critical state in September 1962, JRR-3 had been in operation for 21 years until March 1983. It was decided that the reactor be removed en-bloc in view of the work schedule, cost and management of the reactor following the removal. In the special method developed jointly by the Japanese Atomic Energy Research Institute and Shimizu Construction Co., Ltd., the reactor main unit was cut off from the building by continuous core boring, with its major components bound in the block with biological shield material (heavy concrete), and then conveyed and stored in a large waste store building constructed near the reactor building. Major work processes described in this report include the cutting off, lifting, horizontal conveyance and lowering of the reactor main unit. The removal of the JRR-3 reactor main unit was successfully carried out safely and quickly by the en-block removal method with radiation exposure dose of the workers being kept at a minimum. Thus the high performance of the en-bloc removal method was demonstrated and, in addition, valuable knowhow and other data were obtained from the work. (Nogami, K.)

  19. Reactor Materials Research

    International Nuclear Information System (INIS)

    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)

  20. The fusion reactor

    International Nuclear Information System (INIS)

    Basic principles of the fusion reactor are outlined. Plasma heating and confinement schemes are described. These confinement systems include the linear Z pinch, magnetic mirrors and Tokamaks. A fusion reactor is described and a discussion is given of its environmental impact and its fuel situation. (R.L.)