Beryllium and lithium resource requirements for solid blanket designs for fusion reactors

International Nuclear Information System (INIS)

Powell, J.R.

1975-01-01

The lithium and beryllium requirements are analyzed for an economy of 10 6 MW(e) CTR 3 capacity using solid blanket fusion reactors. The total lithium inventory in fusion reactors is only approximately 0.2 percent of projected U. S. resources. The lithium inventory in the fusion reactors is almost entirely 6 Li, which must be extracted from natural lithium. Approximately 5 percent of natural lithium can be extracted as 6 Li. Thus the total feed of natural lithium required is approximately 20 times that actually used in fusion reactors, or approximately 4 percent of U. S. resources. Almost all of this feed is returned to the U. S. resource base after 6 Li is extracted, however. The beryllium requirements are on the order of 10 percent of projected U. S. resources. Further, the present cost of lithium and the cost of beryllium extraction could both be increased tenfold with only minor effects on CTR capital cost. Such an increase should substantially multiply the economically recoverable resources of lithium and beryllium. It is concluded that there are no lithium or beryllium resource limitations preventing large-scale implementation of solid blanket fusion reactors. (U.S.)

Contribution to the modelling of gas-solid reactions and reactors; Contribution a la modelisation des reactions et des reacteurs gaz-solide

Energy Technology Data Exchange (ETDEWEB)

Patisson, F

2005-09-15

Gas-solid reactions control a great number of major industrial processes involving matter transformation. This dissertation aims at showing that mathematical modelling is a useful tool for both understanding phenomena and optimising processes. First, the physical processes associated with a gas-solid reaction are presented in detail for a single particle, together with the corresponding available kinetic grain models. A second part is devoted to the modelling of multiparticle reactors. Different approaches, notably for coupling grain models and reactor models, are illustrated through various case studies: coal pyrolysis in a rotary kiln, production of uranium tetrafluoride in a moving bed furnace, on-grate incineration of municipal solid wastes, thermogravimetric apparatus, nuclear fuel making, steel-making electric arc furnace. (author)

A reactor/separator device for use in automated solid phase immunoassay

International Nuclear Information System (INIS)

Farina, P.R.; Ordonez, K.P.; Siewers, I.J.

1979-01-01

A reactor/separator device is described for use in automated solid phase immunoassay, including radioimmunoassays. The device is a column fitted at the bottom portion with a water impermeable disc which can hold, for example, immunoabsorbents, immobilized antisera or ion exchange resins. When the contents of the column supported by the disc are brought into contact with an aqueous phase containing reagents or reactants, a chemical reaction is initiated. After the reaction, centrifugally applied pressure forces the aqueous phase through the filter disc making it water permeable and separating a desired component for subsequent analysis. The reactor/separator device of the present invention permits kinetic solid phase assays (non-equilibrium conditions) to be carried out which would be difficult to perform by other conventional methods. (author)

Radiation Damage in Reactor Materials. Part of the Proceedings of the Symposium on Radiation Damage in Solids and Reactor Materials

Energy Technology Data Exchange (ETDEWEB)

NONE

1963-08-15

Radiation damage has presented a new design parameter for the selection of materials to be used in fuel and cladding elements, moderators, structural components and pressure vessels in nuclear reactors. The severe and novel requirements for certain optimum combinations of physical and nuclear properties have emphasized the need for a better understanding of the basic mechanisms of radiation damage. This knowledge is not only essential for progress in the field of nuclear energy, but has direct applications to space technology and semi-conductor research as well. The IAEA, as part of its programme of promoting nuclear technology, therefore convened the Symposium on Radiation Damage in Solids and Reactor Materials, 7-11 May 1962. At the invitation of, and with generous material assistance from, the Government of Italy, the Symposium was held at Venice. The Symposium was primarily concerned with the investigation of the fundamental processes of radiation that underlie the behaviour of metals, alloys and ceramics that are actually useful or potentially useful reactor materials. Two sessions were devoted to studies of irradiation effects on simple metals, as these effects are easiest to interpret. Other topics included general theory, alloys, fissionable and moderator materials and special experimental techniques for radiation damage studies. The properties influenced by irradiation which were of main concern were those of primary importance to the behaviour of solids as reactor materials (e. g. dimensional stability, phase transformation, radiation hardening, fracture, fission-gas escape from uranium and its compounds). Other properties, such as optical, electrical and magnetic properties, and effects on semiconductors, ionic and other non-metallic crystals are also of interest in that these studies can increase our knowledge of the mechanism of radiation damage in solids and provide a tool for investigation into the physics of the solid state by offering a means of

Radiation Damage in Reactor Materials. Part of the Proceedings of the Symposium on Radiation Damage in Solids and Reactor Materials

International Nuclear Information System (INIS)

1963-01-01

Radiation damage has presented a new design parameter for the selection of materials to be used in fuel and cladding elements, moderators, structural components and pressure vessels in nuclear reactors. The severe and novel requirements for certain optimum combinations of physical and nuclear properties have emphasized the need for a better understanding of the basic mechanisms of radiation damage. This knowledge is not only essential for progress in the field of nuclear energy, but has direct applications to space technology and semi-conductor research as well. The IAEA, as part of its programme of promoting nuclear technology, therefore convened the Symposium on Radiation Damage in Solids and Reactor Materials, 7-11 May 1962. At the invitation of, and with generous material assistance from, the Government of Italy, the Symposium was held at Venice. The Symposium was primarily concerned with the investigation of the fundamental processes of radiation that underlie the behaviour of metals, alloys and ceramics that are actually useful or potentially useful reactor materials. Two sessions were devoted to studies of irradiation effects on simple metals, as these effects are easiest to interpret. Other topics included general theory, alloys, fissionable and moderator materials and special experimental techniques for radiation damage studies. The properties influenced by irradiation which were of main concern were those of primary importance to the behaviour of solids as reactor materials (e. g. dimensional stability, phase transformation, radiation hardening, fracture, fission-gas escape from uranium and its compounds). Other properties, such as optical, electrical and magnetic properties, and effects on semiconductors, ionic and other non-metallic crystals are also of interest in that these studies can increase our knowledge of the mechanism of radiation damage in solids and provide a tool for investigation into the physics of the solid state by offering a means of

High-temperature process heat reactor with solid coolant and radiant heat exchange

International Nuclear Information System (INIS)

Alekseev, A.M.; Bulkin, Yu.M.; Vasil'ev, S.I.

1984-01-01

The high temperature graphite reactor with the solid coolant in which heat transfer is realized by radiant heat exchange is described. Neutron-physical and thermal-technological features of the reactor are considered. The reactor vessel is made of sheet carbon steel in the form of a sealed rectangular annular box. The moderator is a set of graphite blocks mounted as rows of arched laying Between the moderator rows the solid coolant annular layings made of graphite blocks with high temperature nuclear fuel in the form of coated microparticles are placed. The coolant layings are mounted onto ring movable platforms, the continuous rotation of which is realizod by special electric drives. Each part of the graphite coolant laying consecutively passes through the reactor core neutron cut-off zones and technological zone. In the core the graphite is heated up to the temperature of 1350 deg C sufficient for effective radiant heat transfer. In the neutron cut-off zone the chain reaction and further graphite heating are stopped. In the technological zone the graphite transfers the accumulated heat to the walls of technological channels in which the working medium moves. The described reactor is supposed to be used in nuclear-chemical complex for ammonia production by the method of methane steam catalytic conversion

Study of the obtainment of Mo_2C by gas-solid reaction in a fixed and rotary bed reactor

International Nuclear Information System (INIS)

Araujo, C.P.B. de; Souza, C.P. de; Souto, M.V.M.; Barbosa, C.M.; Frota, A.V.V.M.

2016-01-01

Carbides' synthesis via gas-solid reaction overcomes many of the difficulties found in other processes, requiring lower temperatures and reaction times than traditional metallurgic routes, for example. In carbides' synthesis in fixed bed reactors (FB) the solid precursor is permeated by the reducing/carburizing gas stream forming a packed bed without mobility. The use of a rotary kiln reactor (RK) adds a mixing character to this process, changing its fluid-particle dynamics. In this work ammonium molybdate was subjected to carbo-reduction reaction (CH4 / H2) in both reactors under the same gas flow (15L / h) and temperature (660 ° C) for 180 minutes. Complete conversion was observed Mo2C (dp = 18.9nm modal particles sizes' distribution) in the fixed bed reactor. In the RK reactor this conversion was only partial (∼ 40%) and Mo2C and MoO3 (34nm dp = bimodal) could be observed on the produced XRD pattern. Partial conversion was attributed to the need to use higher solids loading in the reactor CR (50% higher) to avoid solids to centrifuge. (author)

The gas-solid trickle-flow reactor for the catalytic oxidation of hydrogen sulphide: a trickle-phase model

NARCIS (Netherlands)

Verver, A.B.; van Swaaij, Willibrordus Petrus Maria

1987-01-01

The oxidation of H2S by O2 producing elemental sulphur has been studied at temperatures of 100–300°C and at atmospheric pressure in a laboratory-scale gas-solid trickle-flow reactor. In this reactor one of the reaction products, i.e. sulphur, is removed continuously by flowing solids. A porous,

An integration scheme for stiff solid-gas reactor models

Directory of Open Access Journals (Sweden)

Bjarne A. Foss

2001-04-01

Full Text Available Many dynamic models encounter numerical integration problems because of a large span in the dynamic modes. In this paper we develop a numerical integration scheme for systems that include a gas phase, and solid and liquid phases, such as a gas-solid reactor. The method is based on neglecting fast dynamic modes and exploiting the structure of the algebraic equations. The integration method is suitable for a large class of industrially relevant systems. The methodology has proven remarkably efficient. It has in practice performed excellent and been a key factor for the success of the industrial simulator for electrochemical furnaces for ferro-alloy production.

Modelling solid-convective flash pyrolysis of straw and wood in the Pyrolysis Centrifuge Reactor

DEFF Research Database (Denmark)

Bech, Niels; Larsen, Morten Boberg; Jensen, Peter Arendt

2009-01-01

in the Pyrolysis Centrifuge Reactor, a novel solid-convective flash pyrolysis reactor. The model relies on the original concept for ablative pyrolysis of particles being pyrolysed through the formation of an intermediate liquid compound which is further degraded to form liquid organics, char, and gas. To describe...

A model for a countercurrent gas—solid—solid trickle flow reactor for equilibrium reactions. The methanol synthesis

NARCIS (Netherlands)

Westerterp, K.R.; Kuczynski, M.

1987-01-01

The theoretical background for a novel, countercurrent gas—solid—solid trickle flow reactor for equilibrium gas reactions is presented. A one-dimensional, steady-state reactor model is developed. The influence of the various process parameters on the reactor performance is discussed. The physical

Solid-Core, Gas-Cooled Reactor for Space and Surface Power

International Nuclear Information System (INIS)

King, Jeffrey C.; El-Genk, Mohamed S.

2006-01-01

The solid-core, gas-cooled, Submersion-Subcritical Safe Space (S and 4) reactor is developed for future space power applications and avoidance of single point failures. The Mo-14%Re reactor core is loaded with uranium nitride fuel in enclosed cavities, cooled by He-30%Xe, and sized to provide 550 kWth for seven years of equivalent full power operation. The beryllium oxide reflector disassembles upon impact on water or soil. In addition to decreasing the reactor and shadow shield mass, Spectral Shift Absorber (SSA) materials added to the reactor core ensure that it remains subcritical in the worst-case submersion accident. With a 0.1 mm thick boron carbide coating on the outside surface of the core block and 0.25 mm thick iridium sleeves around the fuel stacks, the reflector outer diameter is 43.5 cm and the combined reactor and shadow shield mass is 935.1 kg. With 12.5 atom% gadolinium-155 added to the fuel, 2.0 mm diameter gadolinium-155 sesquioxide intersititial pins, and a 0.1 mm thick gadolinium-155 sesquioxide coating, the S and 4 reactor has a slightly smaller reflector outer diameter of 43.0 cm, and a total reactor and shield mass of 901.7 kg. With 8.0 atom% europium-151 added to the fuel, 2.0 mm diameter europium-151 sesquioxide interstitial pins, and a 0.1 mm thick europium-151 sesquioxide coating, the reflector's outer diameter and the total reactor and shield mass are further reduced to 41.5 cm and 869.2 kg, respectively

SoLid: Search for Oscillations with Lithium-6 Detector at the SCK-CEN BR2 reactor

Science.gov (United States)

Ban, G.; Beaumont, W.; Buhour, J. M.; Coupé, B.; Cucoanes, A. S.; D'Hondt, J.; Durand, D.; Fallot, M.; Fresneau, S.; Giot, L.; Guillon, B.; Guilloux, G.; Janssen, X.; Kalcheva, S.; Koonen, E.; Labare, M.; Moortgat, C.; Pronost, G.; Raes, L.; Ryckbosch, D.; Ryder, N.; Shitov, Y.; Vacheret, A.; Van Mulders, P.; Van Remortel, N.; Weber, A.; Yermia, F.

2016-04-01

Sterile neutrinos have been considered as a possible explanation for the recent reactor and Gallium anomalies arising from reanalysis of reactor flux and calibration data of previous neutrino experiments. A way to test this hypothesis is to look for distortions of the anti-neutrino energy caused by oscillation from active to sterile neutrino at close stand-off (˜ 6- 8m) of a compact reactor core. Due to the low rate of anti-neutrino interactions the main challenge in such measurement is to control the high level of gamma rays and neutron background. The SoLid experiment is a proposal to search for active-to-sterile anti-neutrino oscillation at very short baseline of the SCK•CEN BR2 research reactor. This experiment uses a novel approach to detect anti-neutrino with a highly segmented detector based on Lithium-6. With the combination of high granularity, high neutron-gamma discrimination using 6LiF:ZnS(Ag) and precise localization of the Inverse Beta Decay products, a better experimental sensitivity can be achieved compared to other state-of-the-art technology. This compact system requires minimum passive shielding allowing for very close stand off to the reactor. The experimental set up of the SoLid experiment and the BR2 reactor will be presented. The new principle of neutrino detection and the detector design with expected performance will be described. The expected sensitivity to new oscillations of the SoLid detector as well as the first measurements made with the 8 kg prototype detector deployed at the BR2 reactor in 2013-2014 will be reported.

Solid radioactive waste processing system for light water cooled reactor plants

International Nuclear Information System (INIS)

Anon.

1979-01-01

Design, construction and performance requirements are given for the operation of the solid radioactive waste processing system for light water-cooled reactor plants. All radioactive or contaminated materials, including spent air and liquid filter elements, spent bead resins, filter sludge, spent powdered resins, evaporator and reverse osmosis concentrates, and dry radioactive wastes are to be processed in appropriate portions of the system. Sections of the standard cover: overall system requirements; equipment requirement; controls and instrumentation; physical arrangement; system capacity and redundancy; operation and maintenance; and system construction and testing. Provisions contained in this standard are to take precedence over ANS-51.1-1973(N18.2-1973) and its revision, ANS-51.8-1975(N18.2a-1975), Sections 2.2 and 2.3. The product resulting from the solid radioactive waste processing system must meet criteria imposed by standards and regulations for transportation and burial (Title 10, Code of Federal Regulations, Part 71, Title 49, Code of Federal Regulations, Parts 100 to 199). As a special feature, all statements in this standard which are related to nuclear safety are set off in boxes

Materials compatibility considerations for a fusion-fission hybrid reactor design

International Nuclear Information System (INIS)

DeVan, J.H.; Tortorelli, P.F.

1983-01-01

The Tandem Mirror Hybrid Reactor is a fusion reactor concept that incorporates a fission-suppressed breeding blanket for the production of 233 U to be used in conventional fission power reactors. The present paper reports on compatibility considerations related to the blanket design. These considerations include solid-solid interactions and liquid metal corrosion. Potential problems are discussed relative to the reference blanket operating temperature (490 0 C) and the recycling time of breeding materials (<1 year)

Radiation protection at the RA Reactor in 1993, Part II, Decontamination and actions, collection of liquid effluents and solid radioactive waste

International Nuclear Information System (INIS)

Mandic, M.; Vukovic, Z.; Lazic, S.; Plecas, I.; Voko, A.

1993-01-01

Certain amount of solid waste results from RA reactor operation, the mean quantity of which depends on the duration of reactor operation and related activities. During repair, when reactor is not operated as well under accidental conditions, the quantity of waste is higher, dependent on the type of repair and comprehensiveness of decontamination of the working surface, contaminated tools and components. The waste is sorted and packed on the spot where they appeared according to the existing regulations and principles of radiation protection with aim to minimize unnecessary exposure of the radiation protection personnel who deals with control, transport, radioactive waste treatment and decontamination. During exceptional operations (decontamination, repair, bigger volume of contaminated material, etc.) professional staff of the Radiation protection department gives recommendations and helps in planning the actions related to repair, sorting and packaging of radioactive waste in special containers, identification of the contaminants, etc. [sr

Modelling of slaughterhouse solid waste anaerobic digestion: determination of parameters and continuous reactor simulation.

Science.gov (United States)

López, Iván; Borzacconi, Liliana

2010-10-01

A model based on the work of Angelidaki et al. (1993) was applied to simulate the anaerobic biodegradation of ruminal contents. In this study, two fractions of solids with different biodegradation rates were considered. A first-order kinetic was used for the easily biodegradable fraction and a kinetic expression that is function of the extracellular enzyme concentration was used for the slowly biodegradable fraction. Batch experiments were performed to obtain an accumulated methane curve that was then used to obtain the model parameters. For this determination, a methodology derived from the "multiple-shooting" method was successfully used. Monte Carlo simulations allowed a confidence range to be obtained for each parameter. Simulations of a continuous reactor were performed using the optimal set of model parameters. The final steady-states were determined as functions of the operational conditions (solids load and residence time). The simulations showed that methane flow peaked at a flow rate of 0.5-0.8 Nm(3)/d/m(reactor)(3) at a residence time of 10-20 days. Simulations allow the adequate selection of operating conditions of a continuous reactor. (c) 2010 Elsevier Ltd. All rights reserved.

Organic free radicals and micropores in solid graphitic carbonaceous matter at the Oklo natural fission reactors, Gabon

International Nuclear Information System (INIS)

Rigali, M.J.; Nagy, B.

1997-01-01

The presence, concentration, and distribution of organic free radicals as well as their association with specific surface areas and microporosities help characterize the evolution and behavior of the Oklo carbonaceous matter. Such information is necessary in order to evaluate uranium mineralization, liquid bitumen solidification, and radio nuclide containment at Oklo. In the Oklo ore deposits and natural fission reactors carbonaceous matter is often referred to as solid graphitic bitumen. The carbonaceous parts of the natural reactors may contain as much as 65.9% organic C by weight in heterogeneous distribution within the clay-rich matrix. The solid carbonaceous matter immobilized small uraninite crystals and some fission products enclosed in this uraninite and thereby facilitated radio nuclide containment in the reactors. Hence, the Oklo natural fission reactors are currently the subjects of detailed studies because they may be useful analogues to support performance assessment of radio nuclide containment at anthropogenic radioactive waste repository sites. Seven carbonaceous matter rich samples from the 1968 ± 50 Ma old natural fission reactors and the associated Oklo uranium ore deposit were studied by electron spin resonance (ESR) spectroscopy and by measurements of specific surface areas (BET method). Humic acid, fulvic acid, and fully crystalline graphite standards were also examined by ESR spectroscopy for comparison with the Oklo solid graphitic bitumens. With one exception, the ancient Oklo bitumens have higher organic free radical concentrations than the modem humic and fulvic acid samples. The presence of carbon free radicals in the graphite standard could not be determined due to the conductivity of this material. 72 refs., 7 figs., 1 tab

Management of radioactive liquid and solid wastes at the Research Reactor Institute, Kyoto University, (3)

International Nuclear Information System (INIS)

Tsutsui, Tenson; Shimoura, K.; Koyama, A.

1977-11-01

In this report, the management of radioactive liquid and solid wastes at the Research Reactor Institute, Kyoto University during past 6 years, from April in 1971 to March in 1977 are reviewed. (auth.)

Characterization of fluidization regime in circulating fluidized bed reactor with high solid particle concentration using computational fluid dynamics

Energy Technology Data Exchange (ETDEWEB)

Chalermsinsuwan, Benjapon; Thummakul, Theeranan; Piumsomboon, Pornpote [Chulalongkorn University, Bangkok (Thailand); Gidaspow, Dimitri [Armour College of Engineering, Chicago (United States)

2014-02-15

The hydrodynamics inside a high solid particle concentration circulating fluidized bed reactor was investigated using computational fluid dynamics simulation. Compared to a low solid particle reactor, all the conventional fluidization regimes were observed. In addition, two unconventional fluidization regimes, circulating-turbulent and dense suspension bypassing regimes, were found with only primary gas injection. The circulating-turbulent fluidization regime showed uniformly dense solid particle distribution in all the system directions, while the dense suspension bypassing fluidization regime exhibited the flow of solid particles at only one side system wall. Then, comprehensive fluidization regime clarification and mapping were evaluated using in-depth system parameters. In the circulating-turbulent fluidization regime, the total granular temperature was low compared to the adjacent fluidization regimes. In the dense suspension bypassing fluidization regime, the highest total granular temperature was obtained. The circulating-turbulent and dense suspension bypassing fluidization regimes are suitable for sorption and transportation applications, respectively.

Enhanced performance of solid oxide electrolysis cells by integration with a partial oxidation reactor: Energy and exergy analyses

International Nuclear Information System (INIS)

Visitdumrongkul, Nuttawut; Tippawan, Phanicha; Authayanun, Suthida; Assabumrungrat, Suttichai; Arpornwichanop, Amornchai

2016-01-01

Highlights: • Process design of solid oxide electrolyzer integrated with a partial oxidation reactor is studied. • Effect of key operating parameters of partial oxidation reactor on the electrolyzer performance is presented. • Exergy analysis of the electrolyzer process is performed. • Partial oxidation reactor can enhance the solid oxide electrolyzer performance. • Partial oxidation reactor in the process is the highest exergy destruction unit. - Abstract: Hydrogen production without carbon dioxide emission has received a large amount of attention recently. A solid oxide electrolysis cell (SOEC) can produce pure hydrogen and oxygen via a steam electrolysis reaction that does not emit greenhouse gases. Due to the high operating temperature of SOEC, an external heat source is required for operation, which also helps to improve SOEC performance and reduce operating electricity. The non-catalytic partial oxidation reaction (POX), which is a highly exothermic reaction, can be used as an external heat source and can be integrated with SOEC. Therefore, the aim of this work is to study the effect of operating parameters of non-catalytic POX (i.e., the oxygen to carbon ratio, operating temperature and pressure) on SOEC performance, including exergy analysis of the process. The study indicates that non-catalytic partial oxidation can enhance the hydrogen production rate and efficiency of the system. In terms of exergy analysis, the non-catalytic partial oxidation reactor is demonstrated to be the highest exergy destruction unit due to irreversible chemical reactions taking place, whereas SOEC is a low exergy destruction unit. This result indicates that the partial oxidation reactor should be improved and optimally designed to obtain a high energy and exergy system efficiency.

Radiation protection at the RA Reactor in 1989, Part -2, Decontamination, collection of treatment of fluid and solid radioactive waste, Annex 3

International Nuclear Information System (INIS)

Mandic, M.; Vukovic, Z.; Plecas, I.; Knezevic, Lj.; Lazic, S.; Bacic, S.

1989-01-01

Certain amount of solid waste results from RA reactor operation, the mean quantity of which depends on the duration of reactor operation and related activities. During repair, when reactor is not operated as well under accidental conditions, the quantity of waste is higher, dependent on the type of repair and comprehensiveness of decontamination of the working surface, contaminated tools and components. The waste is sorted and packed on the spot where they appeared according to the existing regulations and principles of radiation protection with aim to minimize unnecessary exposure of the radiation protection personnel who deals with control, transport, radioactive waste treatment and decontamination. During exceptional operations (decontamination, repair, bigger volume of contaminated material, etc.) professional staff of the Radiation protection department gives recommendations and helps in planning the actions related to repair, sorting and packaging of radioactive waste in special containers, identification of the contaminants, etc. [sr

Characterization of solids in the Three Mile Island Unit 2 reactor defueling water

International Nuclear Information System (INIS)

Campbell, D.O.

1987-12-01

Because of the impact of poor water clarity on defueling operations at the Three Mile Island Unit 2 Nuclear Power Station, a study was undertaken to characterize suspended particulates in the reactor defueling water. The examination included cascade filtration through Nuclepore filters of progressively smaller pore sizes, using three water samples obtained at different times and after varying degrees of clarification. The solids collected on the filters were examined with a scanning electron microscope and analyzed with energy-dispersive x-ray fluorescence. A wide variety of solids was observed, and 26 elements were detected. These included all the materials expected from the reactor system (uranium, zirconium, silver, cadmium, indium, iron, chromium, and nickel), chemicals and zeolites used to decontaminate the water (aluminum, silicon, sodium), common impurities (potassium, chlorine, sulfur, magnesium, calcium, and others), as well as some unexpected metals (molybdenum, manganese, bromine, and lead). There was also evidence for the presence of organic material. A diverse assortment of particles with widely varying surface properties was found to be present

Biological treatment of petroleum sludges in liquid/solids contact reactors

Energy Technology Data Exchange (ETDEWEB)

Stroo, H F [Remediation Technologies, Inc., Kent, WA (USA)

1989-10-01

Biological treatment of hazardous wastes (bioremediation) is now recognized as an effective and cost-efficient approach for on-site cleanup of petroleum-contaminated soils and sludges. These strategies may require pretreatment of oily sludges produced as refinery wastes. Recent work has shown that liquid/solids contact (LSC) bioreactors are capable of adequate pretreatment at lower cost than competing technologies. Since LSC operations aim to maximize microbial numbers and activity, inexpensive microbiological monitoring can provide rapid feedback on performance. LSC technology represents a method for rapid biological treatment of petroleum sludges in a contained reactor. The technology has proven highly effective for a variety of oil refinery sludges, with degradation rates up to ten times faster than those observed during land treatment. The most promising use of LSC is a pretreatment. Because biological treatment in LSC can degrade and detoxify contaminants rapidly and relatively inexpensively, with little risk of off-site contamination, this technology should be considered by refiners having to close sites or treat current waste-streams. 7 refs., 1 figs., 1 tab.

CO_2 capture with solid sorbent: CFD model of an innovative reactor concept

International Nuclear Information System (INIS)

Barelli, L.; Bidini, G.; Gallorini, F.

2016-01-01

Highlights: • A new reactor solution based on rotating fixed beds was presented. • The preliminary design of the reactor was approached. • A CFD model of the reactor, including CO_2 capture kinetic, was developed. • The CFD model is validated with experimental results. • Sorbent exploitation increasing is possible thanks to the new reactor. - Abstract: In future decarbonization scenarios, CCS with particular reference to post-combustion technologies will be an important option also for energy intensive industries. Nevertheless, today CCS systems are rarely installed due to high energy and cost penalties of current technology based on chemical scrubbing with amine solvent. Therefore, innovative solutions based on new/optimized solvents, sorbents, membranes and new process designs, are R&D priorities. Regarding the CO_2 capture through solid sorbents, a new reactor solution based on rotating fixed beds is presented in this paper. In order to design the innovative system, a suitable CFD model was developed considering also the kinetic capture process. The model was validated with experimental results obtained by the authors in previous research activities, showing a potential reduction of energy penalties respect to current technologies. In the future, the model will be used to identify the control logic of the innovative reactor in order to verify improvements in terms of sorbent exploitation and reduction of system energy consumption.

Radiation protection at the RA Reactor in 1995, Part -2, Annex 2, Decontamination and actions, collection of liquid effluents and solid radioactive waste

International Nuclear Information System (INIS)

Mandic, M.; Vukovic, Z.; Lazic, S.; Plecas, I.; Voko, A.

1995-01-01

Certain amount of solid waste results from RA reactor operation, the mean quantity of which depends on the duration of reactor operation and related activities. During repair, when reactor is not operated as well under accidental conditions, the quantity of waste is higher, dependent on the type of repair and comprehensiveness of decontamination of the working surface, contaminated tools and components. The waste is sorted and packed on the spot where they appeared according to the existing regulations and principles of radiation protection with aim to minimize unnecessary exposure of the radiation protection personnel who deals with control, transport, radioactive waste treatment and decontamination. During exceptional operations (decontamination, repair, bigger volume of contaminated material, etc.) professional staff of the Radiation protection department gives recommendations and helps in planning the actions related to repair, sorting and packaging of radioactive waste in special containers, identification of the contaminants, etc. [sr

Radiation protection at the RA Reactor in 1998, Part 2, Annex 2, Decontamination and actions, collection of liquid effluents and solid radioactive waste

International Nuclear Information System (INIS)

Mandic, M.; Vukovic, Z.; Bacic, S.; Plecas, I.

1998-01-01

Certain amount of solid waste results from RA reactor operation, the mean quantity of which depends on the duration of reactor operation and related activities. During repair, when reactor is not operated as well under accidental conditions, the quantity of waste is higher, dependent on the type of repair and comprehensiveness of decontamination of the working surface, contaminated tools and components. The waste is sorted and packed on the spot where they appeared according to the existing regulations and principles of radiation protection with aim to minimize unnecessary exposure of the radiation protection personnel who deals with control, transport, radioactive waste treatment and decontamination. During exceptional operations (decontamination, repair, bigger volume of contaminated material, etc.) professional staff of the Radiation protection department gives recommendations and helps in planning the actions related to repair, sorting and packaging of radioactive waste in special containers, identification of the contaminants, etc. [sr

Anaerobic treatment of wastewater with high suspended solids from a bulk drug industry using fixed film reactor (AFFR).

Science.gov (United States)

Gangagni Rao, A; Venkata Naidu, G; Krishna Prasad, K; Chandrasekhar Rao, N; Venkata Mohan, S; Jetty, Annapurna; Sarma, P N

2005-01-01

Studies were carried out on the treatment of wastewater from a bulk drug industry using an anaerobic fixed film reactor (AFFR) designed and fabricated in the laboratory. The chemical oxygen demand (COD) and total dissolved solids (TDS) of the wastewater were found to be very high with low biochemical oxygen demand (BOD) to COD ratio and high total suspended solid (TSS) concentration. Acclimatization of seed consortia and startup of the reactor was carried out by directly using the wastewater, which resulted in reducing the period of startup to 30 days. The reactor was studied at different organic loading rates (OLR) and it was found that the optimum OLR was 10 kg COD/m(3)/day. The wastewater under investigation, which had a considerable quantity of SS, was treated anaerobically without any pretreatment. COD and BOD of the reactor outlet wastewater were monitored and at steady state and optimum OLR 60-70% of COD and 80-90% of BOD were removed. The reactor was subjected to organic shock loads at two different OLR and the reaction could withstand the shocks and performance could be restored to normalcy at that OLR. The results obtained indicated that AFFR could be used efficiently for the treatment of wastewater from a bulk drug industry having high COD, TDS and TSS.

Solid-state track recorder neutron dosimetry in light water reactor pressure vessel surveillance mockups

International Nuclear Information System (INIS)

Ruddy, F.H.; Roberts, J.H.; Gold, R.; Preston, C.C.

1984-09-01

Solid-State Track Recorder (SSTR) measurements of neutron-induced fission rates have been made in several pressure vessel mockup facilities as part of the US Nuclear Regulatory Commission's (NRC) Light Water Reactor Pressure Vessel Surveillance Dosimetry Improvement Program (LWR-PV-SDIP). The results of extensive physics-dosimetry measurements made at the Pool Critical Assembly (PCA) at Oak Ridge National Laboratory (ORNL) in Oak Ridge, TN are summarized. Included are 235 U, 238 U, 237 Np and 232 Th fission rates in the PCA 12/13, 8/7, and 4/12 SSC configurations. Additional low power measurements have been made in an engineering mockup at the VENUS critical assembly at CEN-SCK, Mol, Belgium. 237 Np and 238 U fission rates were made at selected locations in the VENUS mockup, which models the in-core and near-core regions of a pressurized water reactor (PWR). Absolute core power measurements were made at VENUS by exposing solid-state track recorders (SSTRs) to polished fuel pellets within in-core fuel pins. 8 references, 4 figures, 10 tables

Oxidation of nitrobenzene by ozone in the presence of faujasite zeolite in a continuous flow gas-liquid-solid reactor.

Science.gov (United States)

Reungoat, J; Pic, J S; Manéro, M H; Debellefontaine, H

2010-01-01

This work investigates the oxidation of nitrobenzene (NB) by ozone in the presence of faujasite zeolite. Experiments were carried out in a gas-liquid-solid reactor were ozone transfer and NB oxidation took place at the same time. Three configurations of the reactor were compared: empty, filled with inert glass beads and filled with faujasite pellets. First, ozone transfer coefficient (k(L)a) and decomposition rate constant (k(C)) were determined for each configuration. In presence of solid, k(L)a was 2.0 to 2.6 times higher and k(C) was 5.0 to 6.4 times higher compared to the empty reactor. Then, the various configurations were evaluated in terms of NB removal and chemical oxygen demand (COD) decrease. The faujasite reactor showed higher removal of NB and decrease of COD compared to other configurations under the same conditions suggesting that the faujasite increases the oxidation rate of NB. Oxidation of NB in presence of faujasite also proved to be limited by the transfer of ozone from the gas to the liquid phase.

Utilization of gases from biomass gasification in a reforming reactor coupled to an integrated planar solid oxide fuel cell: Simulation analysis

Directory of Open Access Journals (Sweden)

Costamagna Paola

2004-01-01

Full Text Available One of the high-efficiency options currently under study for a rational employment of hydrogen are fuel cells. In this scenario, the integrated planar solid oxide fuel cell is a new concept recently proposed by Rolls-Royce. The basic unit of a modular plant is the so called "strip", containing an electro-chemical reactor formed by a number of IP-SOFC modules, and a reforming reactor. For a better under standing of the behavior of a system of this kind, a simulation model has been set up for both the electrochemical reactor and the reformer; both models follow the approach typically employed in the simulation of chemical reactors, based on the solution of mass and energy balances. In the case of the IP-SOFC electro chemical reactor, the model includes the calculation of the electrical resistance of the stack (that is essentially due to ohmic losses, activation polar is action and mass transport limitations, the mass balances of the gaseous flows, the energy balances of gaseous flows (anodic and cathodic and of the solid. The strip is designed in such a way that the reaction in the reforming reactor is thermally sustained by the sensible heat of the hot air exiting the electrochemical section; this heat exchange is taken into account in the model of the reformer, which includes the energy balance of gaseous flows and of the solid structure. Simulation results are reported and discussed for both the electrochemical reactor in stand-alone configuration (including comparison to experimental data in a narrow range of operating conditions and for the complete strip.

Solid-state track recorder neutron dosimetry in the Three-Mile Island Unit-2 reactor cavity

International Nuclear Information System (INIS)

Gold, R.; Roberts, J.H.; Ruddy, F.H.; Preston, C.C.; McElroy, W.N.

1985-04-01

Solid-state track recorder (SSTR) neutron dosimetry has been conducted in the Three-Mile Island Unit (TMI-2) reactor cavity (i.e., the annular gap between the pressure vessel and the biological shield) for nondestructive assessment of the fuel distribution. Two axial stringers were deployed in the annular gap with 17 SSTR dosimeters located on each stringer. SSTR experimental results reveal that neutron streaming, upward from the bottom of the reactor cavity region, dominates the observed neutron intensity. These absolute thermal neutron flux observations are consistent with the presence of a significant amount of fuel debris lying at the bottom of the reactor vessel. A conservative lower bound estimated from these SSTR data implies that there are at least 2 tonnes of fuel, which is roughly 4 fuel assemblies, at the bottom of the vessel. The existence of significant neutron streaming also explains the high count rate observed with the source range monitors (SRMs) that are located in the TMI-2 reactor cavity

Flow electrochemical biosensors based on enzymatic porous reactor and tubular detector of silver solid amalgam

Energy Technology Data Exchange (ETDEWEB)

Josypčuk, Bohdan, E-mail: josypcuk@jh-inst.cas.cz [J. Heyrovský Institute of Physical Chemistry of AS CR, v.v.i., Department of Biophysical Chemistry, Dolejskova 3, Prague (Czech Republic); Barek, Jiří [Charles University in Prague, Faculty of Science, University Center of Excellence UNCE “Supramolecular Chemistry”, Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry, Albertov 6, CZ-128 43 Prague 2 (Czech Republic); Josypčuk, Oksana [J. Heyrovský Institute of Physical Chemistry of AS CR, v.v.i., Department of Biophysical Chemistry, Dolejskova 3, Prague (Czech Republic); Charles University in Prague, Faculty of Science, University Center of Excellence UNCE “Supramolecular Chemistry”, Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry, Albertov 6, CZ-128 43 Prague 2 (Czech Republic)

2013-05-17

Graphical abstract: -- Highlights: •Flow amperometric enzymatic biosensor was constructed. •The biosensor is based on a reactor of a novel material – porous silver solid amalgam. •Tubular amalgam detector was used for determination of decrease of O{sub 2} concentration. •Covalent bonds amalgam−thiol−enzyme contributed to the sensor long-term stability. •LOD of glucose was 0.01 mmol L{sup −1} with RSD = 1.3% (n = 11). -- Abstract: A flow amperometric enzymatic biosensor for the determination of glucose was constructed. The biosensor consists of a flow reactor based on porous silver solid amalgam (AgSA) and a flow tubular detector based on compact AgSA. The preparation of the sensor and the determination of glucose occurred in three steps. First, a self-assembled monolayer of 11-mercaptoundecanoic acid (MUA) was formed at the porous surface of the reactor. Second, enzyme glucose oxidase (GOx) was covalently immobilized at MUA-layer using N-ethyl-N′-(3-dimethylaminopropyl) carboimide and N-hydroxysuccinimide chemistry. Finally, a decrease of oxygen concentration (directly proportional to the concentration of glucose) during enzymatic reaction was amperometrically measured on the tubular detector under flow injection conditions. The following parameters of glucose determination were optimized with respect to amperometric response: composition of the mobile phase, its concentration, the potential of detection and the flow rate. The calibration curve of glucose was linear in the concentration range of 0.02–0.80 mmol L{sup −1} with detection limit of 0.01 mmol L{sup −1}. The content of glucose in the sample of honey was determined as 35.5 ± 1.0 mass % (number of the repeated measurements n = 7; standard deviation SD = 1.2%; relative standard deviation RSD = 3.2%) which corresponds well with the declared values. The tested biosensor proved good long-term stability (77% of the current response of glucose was retained after 35 days)

Current safety issues related to research reactor operation

International Nuclear Information System (INIS)

Alcala-Ruiz, F.

2000-01-01

The Agency has included activities on research reactor safety in its Programme and Budget (P and B) since its inception in 1957. Since then, these activities have traditionally been oriented to fulfil the Agency's functions and obligations. At the end of the decade of the eighties, the Agency's Research Reactor Safety Programme (RRSP) consisted of a limited number of tasks related to the preparation of safety related publications and the conduct of safety missions to research reactor facilities. It was at the beginning of the nineties when the RRSP was upgraded and expanded as a subprogramme of the Agency's P and B. This subprogramme continued including activities related to the above subjects and started addressing an increasing number of issues related to the current situation of research reactors (in operation and shut down) around the world such as reactor ageing, modifications and decommissioning. The present paper discusses some of the above issues as recognised by various external review or advisory groups (e.g., Peer Review Groups under the Agency's Performance Programme Appraisal System (PPAS) or the standing International Nuclear Safety Advisory Group (INSAG)) and the impact of their recommendations on the preparation and implementation of the part of the Agency's P and B relating to the above subject. (author)

Study of gas-solid contact in an ultra-rapid reactor for cumene catalytic cracking; Etude du contact gaz-solide dans un reacteur a co-courant descendant par la mise en oeuvre du craquage catalytique du cumene

Energy Technology Data Exchange (ETDEWEB)

Bayle, J

1996-11-05

Few studies have been carried out on the notion of gas-solid contact in ultra-rapid reactors. Both gas and solid move in the reactor and the contact can be directly estimated when using a chemical reaction such as cumene cracking. It`s a pure and light feedstock whose kinetics can be determined in a fixed bed. The study was carried out on a downflow ultra-rapid reactor (ID = 20 mm, length = 1 m) at the University of Western Ontario. It proved that the quench and the ultra-rapid separation of gas and solid must be carefully designed in the pilot plant. Cumene conversion dropped when reducing gas-solid contact, which led to push the temperature over 550 deg. C and increase the cat/oil ratio at 25 working at solid mass fluxes below 85 kg/m{sup 2}.s. Change of selectivity at very short residence time were also observed due to deactivation effects. Experiments made by Roques (1994) with phosphorescent pigments on the Residence Time Distribution of solids gave Hydrodynamic data on a cold flow copy of the pilot plant. Experiments made on packed bed gave kinetic data on the cracking of cumene. These data were combined to optimize a mono dimensional plug flow model for cumene cracking. (author)

Automatic reactor for solid-phase synthesis of molecularly imprinted polymeric nanoparticles (MIP NPs) in water.

Science.gov (United States)

Poma, Alessandro; Guerreiro, Antonio; Caygill, Sarah; Moczko, Ewa; Piletsky, Sergey

We report the development of an automated chemical reactor for solid-phase synthesis of MIP NPs in water. Operational parameters are under computer control, requiring minimal operator intervention. In this study, "ready for use" MIP NPs with sub-nanomolar affinity are prepared against pepsin A, trypsin and α-amylase in only 4 hours.

Scrap tyre recycling process with molten zinc as direct heat transfer and solids separation fluid: A new reactor concept.

Science.gov (United States)

Riedewald, Frank; Goode, Kieran; Sexton, Aidan; Sousa-Gallagher, Maria J

2016-01-01

Every year about 1.5 billion tyres are discarded worldwide representing a large amount of solid waste, but also a largely untapped source of raw materials. The objective of the method was to prove the concept of a novel scrap tyre recycling process which uses molten zinc as the direct heat transfer fluid and, simultaneously, uses this media to separate the solids products (i.e. steel and rCB) in a sink-float separation at an operating temperature of 450-470 °C. This methodology involved: •construction of the laboratory scale batch reactor,•separation of floating rCB from the zinc,•recovery of the steel from the bottom of the reactor following pyrolysis.

SACCHARIFICATION OF NATIVE CASSAVA STARCH AT HIGH DRY SOLIDS IN AN ENZYMATIC MEMBRANE REACTOR

Directory of Open Access Journals (Sweden)

I Nyoman Widiasa

2012-02-01

Full Text Available This study is aimed to develop a novel process scheme for hydrolysis of native cassava starch at high dry solids using an enzymatic membrane reactor (EMR. Firstly, liquefied cassava starch having solids content up to 50% by weight was prepared by three stage liquefactions in a conventional equipment using a commercially available heat stable a-amylase (Termamyl 120L. The liquefied cassava starch was further saccharified in an EMR using glucoamylase (AMG E. By using the developed process scheme, a highly clear hydrolysate with dextrose equivalent (DE approximately 97 could be produced, provided the increase of solution viscosity during the liquefaction was precisely controlled. The excessive space time could result in reduction in conversion degree of starch. Moreover, a residence time distribution study confirmed that the EMR could be modelled as a simple continuous stirred tank reactor (CSTR. Using Lineweaver-Burk analysis, the apparent Michaelis-Menten constant (Km and glucose production rate constant (k2 were 552 (g/l and 4.04 (min-1, respectively. Application of simple CSTR model with those kinetic parameters was quietly appropriate to predict the reactor’s performance at low space time.

Neutron dosimetry in the Three-Mile Island Unit 2 reactor cavity with solid-state track recorders

International Nuclear Information System (INIS)

Gold, R.; Roberts, J.H.; Ruddy, F.H.; Preston, C.C.; McElroy, W.N.; Rao, S.V.; Greenborg, J.; Fricke, V.R.

1986-01-01

Solid-state track recorder (SSTR) neutron dosimetry has been conducted in the Three-Mile Island Unit 2 (TMI-2) reactor cavity, for nondestructive assessment of the fuel distribution. Two axial stringers were deployed in the annular gap with 17 SSTR dosimeters located on each stringer. SSTR experimental results reveal that neutron streaming, upward from the bottom of the reactor cavity region, dominates the observed neutron intensity. These absolute thermal neutron flux observations are consistent with the presence of a significant amount of fuel debris lying at the bottom of the reactor vessel. A conservative lower bound estimated from these SSTR data implies that at least 2 tonnes of fuel, which is roughly 4 fuel assemblies, is lying at the bottom of the vessel. This existence of significant neutron streaming also explains the high count rate observed with the source range monitors that are located in the TMI-2 reactor cavity. (author)

Automatic reactor for solid-phase synthesis of molecularly imprinted polymeric nanoparticles (MIP NPs) in water

OpenAIRE

Poma, Alessandro; Guerreiro, Antonio; Caygill, Sarah; Moczko, Ewa; Piletsky, Sergey

2014-01-01

We report the development of an automated chemical reactor for solid-phase synthesis of MIP NPs in water. Operational parameters are under computer control, requiring minimal operator intervention. In this study, “ready for use” MIP NPs with sub-nanomolar affinity are prepared against pepsin A, trypsin and α-amylase in only 4 hours.

Slurry reactors

Energy Technology Data Exchange (ETDEWEB)

Kuerten, H; Zehner, P [BASF A.G., Ludwigshafen am Rhein (Germany, F.R.)

1979-08-01

Slurry reactors are designed on the basis of empirical data and model investigations. It is as yet not possible to calculate the flow behavior of such reactors. The swarm of gas bubbles and cluster formations of solid particles and their interaction in industrial reactors are not known. These effects control to a large extent the gas hold-up, the gas-liquid interface and, similarly as in bubble columns, the back-mixing of liquids and solids. These hydrodynamic problems are illustrated in slurry reactors which constructionally may be bubble columns, stirred tanks or jet loop reactors. The expected effects are predicted by means of tests with model systems modified to represent the conditions in industrial hydrogenation reactors. In his book 'Mass Transfer in Heterogeneous Catalysis' (1970) Satterfield complained of the lack of knowledge about the design of slurry reactors and hence of the impossible task of the engineer who has to design a plant according to accepted rules. There have been no fundamental changes since then. This paper presents the problems facing the engineer in designing slurry reactors, and shows new development trends.

Dynamic Modeling and Control Studies of a Two-Stage Bubbling Fluidized Bed Adsorber-Reactor for Solid-Sorbent CO{sub 2} Capture

Energy Technology Data Exchange (ETDEWEB)

Modekurti, Srinivasarao; Bhattacharyya, Debangsu; Zitney, Stephen E.

2013-07-31

A one-dimensional, non-isothermal, pressure-driven dynamic model has been developed for a two-stage bubbling fluidized bed (BFB) adsorber-reactor for solid-sorbent carbon dioxide (CO{sub 2}) capture using Aspen Custom Modeler® (ACM). The BFB model for the flow of gas through a continuous phase of downward moving solids considers three regions: emulsion, bubble, and cloud-wake. Both the upper and lower reactor stages are of overflow-type configuration, i.e., the solids leave from the top of each stage. In addition, dynamic models have been developed for the downcomer that transfers solids between the stages and the exit hopper that removes solids from the bottom of the bed. The models of all auxiliary equipment such as valves and gas distributor have been integrated with the main model of the two-stage adsorber reactor. Using the developed dynamic model, the transient responses of various process variables such as CO{sub 2} capture rate and flue gas outlet temperatures have been studied by simulating typical disturbances such as change in the temperature, flowrate, and composition of the incoming flue gas from pulverized coal-fired power plants. In control studies, the performance of a proportional-integral-derivative (PID) controller, feedback-augmented feedforward controller, and linear model predictive controller (LMPC) are evaluated for maintaining the overall CO{sub 2} capture rate at a desired level in the face of typical disturbances.

Mirror reactor surface study

Energy Technology Data Exchange (ETDEWEB)

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

1976-09-01

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

Mirror reactor surface study

International Nuclear Information System (INIS)

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

1976-01-01

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

Neutronic calculations for the conceptual design of an in-reactor solid breeder experiment, TRIO-01

International Nuclear Information System (INIS)

Childs, R.L.; Gabriel, T.A.; Lillie, R.A.

1981-03-01

Neutronics calculations have been performed to obtain tritium production and heat generation rates for the irradiation of solid tritium breeding materials in the Oak Ridge Research Reactor (ORR). Two breeder materials, Li 2 O and LiAlO 2 , were considered. Burnup calculations were performed to estimate the amount of 6 Li present as a function of time

Method and apparatus for suppressing water-solid overpressurization of coolant in nuclear reactor power apparatus

International Nuclear Information System (INIS)

Aanstad, O.J.; Sklencar, A.M.

1983-01-01

A reactor-coolant relief valve is opened for increase in mass influx if the rate of change of coolant pressure exceeds a setpoint during a predetermined interval, if, during this interval, the coolant temperature is less than a setpoint and if the level of the fluid in the pressurizer is above a predetermined setpoint (water-solid state). (author)

SoLid Detector Technology

Science.gov (United States)

Labare, Mathieu

2017-09-01

SoLid is a reactor anti-neutrino experiment where a novel detector is deployed at a minimum distance of 5.5 m from a nuclear reactor core. The purpose of the experiment is three-fold: to search for neutrino oscillations at a very short baseline; to measure the pure 235U neutrino energy spectrum; and to demonstrate the feasibility of neutrino detectors for reactor monitoring. This report presents the unique features of the SoLid detector technology. The technology has been optimised for a high background environment resulting from low overburden and the vicinity of a nuclear reactor. The versatility of the detector technology is demonstrated with a 288 kg detector prototype which was deployed at the BR2 nuclear reactor in 2015. The data presented includes both reactor on, reactor off and calibration measurements. The measurement results are compared with Monte Carlo simulations. The 1.6t SoLid detector is currently under construction, with an optimised design and upgraded material technology to enhance the detector capabilities. Its deployement on site is planned for the begin of 2017 and offers the prospect to resolve the reactor anomaly within about two years.

Neutron dosimetry in the Three-Mile Island Unit 2 reactor cavity with solid-state track recorders

International Nuclear Information System (INIS)

Gold, R.; Roberts, J.H.; Ruddy, F.H.; Preston, C.C.; McElroy, W.N.; Rao, S.V.; Greenborg, J.; Fricke, V.R.

1985-01-01

Solid-state track recorder (SSTR) neutron dosimetry has been conducted in the Three-Mile Island Unit 2 (TMI-2) reactor cavity (i.e., the annular gap between the pressure vessel and the biological shield) for nondestructive assessment of the fuel distribution. Two axial stringers were deployed in the annular gap with 17 SSTR dosimeters located on each stringer. SSTR experimental results reveal that neutron streaming, upward from the bottom of the reactor cavity region, dominates the observed neutron intensity. These absolute thermal neutron flux observations are consistent with the presence of a significant amount of fuel debris lying at the bottom of the reactor vessel. A conservative lower bound estimated from these SSTR data implies that at least 2 tonnes of fuel, which is roughly 4 fuel assemblies, is lying at the bottom of the vessel. The existence of significant neutron streaming also explains the high count rate observed with the source range monitors (SRMs) that are located in the TMI-2 reactor cavity

Radiation protection at the RA Reactor in 1985, Part -4, decontamination and treatment of solid radioactive materials for the needs of RA reactor

International Nuclear Information System (INIS)

Plecas, I.; Vukovic, Z.; Blagojevic, R.; Kostadinovic, A.

1985-01-01

This report describes the activity of the decontamination and treatment team for the needs of the RA reactor, its equipment, working conditions, methods for decontamination, means of decontamination, type and quantity of decontaminated surfaces, number of decontaminated objects, quantity of collected radioactive solid wastes, their packaging, transport to the storage place and topography od radiation field in the storage during 1985 [sr

Development status of oxygen solid electrolyte sensors in HLMC in respect to monoblock reactor facilities

International Nuclear Information System (INIS)

Martynov, P.N.; Askhadullin, R.Sh.; Storozhenko, A.N.; Shelemet'ev, V.M.; Sadovnichij, R.P.; Ivanov, I.I.

2014-01-01

The results of developing sensors on the base of solid electrolytes to control oxygen in lead and lead-bismuth coolants are considered. It is found out that ceramic detecting elements on the base of solid electrolytes from oxide ceramics are able to work a long time in conditions of high temperatures and thermal shocks in molten metals (in gases). They show stable conducting and mechanical properties, thermal resistance, low gas permeability. Using considered detecting elements different sensors, including ones for monoblock reactors and facilities, are developed and manufactured. The given sensors can be used for both continuous and periodical oxygen control in heavy liquid metal coolants [ru

Solidification of liquid concentrate and solid waste generated as by-products of the liquid radwaste treatment systems in light-water reactors

International Nuclear Information System (INIS)

Neilson, R.M. Jr.; Colombo, P.

1977-01-01

The treatment of liquid concentrate and solid waste produced in light-water reactors as by-products of liquid radwaste treatment systems consists of five basic operations: waste collection, waste pretreatment, solidification agent handling, mixing/packaging (solidification) and waste package handling. This paper will concern itself primarily with the solidification operation, however, the other operations enumerated as well as the types of wastes treated and their origins will be briefly described, especially with regards to their effects on solidification. During solidification, liquid concentrate and solid wastes are incorporated with a solidification agent to form a monolithic, free-standing solid. The basic solidification agent types either currently used in the United States or proposed for use include absorbants, hydraulic cement, urea-formaldehyde, other polymer systems, and bitumen. The operation, formulations and limitations of these agents as used for radwaste solidification will be discussed. Properties relevant to the evaluation of solidified waste forms will be identified and relative comparisons made for wastes solidified by various processes

Genetic structure of the Danish red deer (Cervus elaphus)

DEFF Research Database (Denmark)

NIELSEN, ELSEMARIE KRAGH; OLESEN, CARSTEN RIIS; PERTOLDI, CINO

2008-01-01

specimens and seven museum specimens. There was a significant difference in mean expected heterozygosity (HE) between the three enclosed areas and the 11 unenclosed areas. Significant departures from Hardy-Weinberg equilibrium were observed in the three enclosed areas and in nine of the unenclosed areas...

A solid-breeder blanket and power conversion system for the Mirror Advanced Reactor Study (MARS)

International Nuclear Information System (INIS)

Bullis, R.; Clarkson, I.

1983-01-01

A solid-breeder blanket has been designed for a commercial fusion power reactor based on the tandem mirror concept (MARS). The design utilizes lithium oxide, cooled by helium which powers a conventional steam electric generating cycle. Maintenance and fabricability considerations led to a modular configuration 6 meters long which incorporates two magnets, shield, blanket and first wall. The modules are arranged to form the 150 meter long reactor central cell. Ferritic steel is used for the module primary structure. The lithium oxide is contained in thin-walled vanadium alloy tubes. A tritium breeding ratio of 1.25 and energy multiplication of 1.1 is predicted. The blanket design appears feasible with only a modest advance in current technology

Reactor physical experimental program EROS in the frame of the molten salt applying reactor concepts development

International Nuclear Information System (INIS)

Hron, Miloslav; Kyncl, Jan; Mikisek, Miroslav

2009-01-01

After the relatively broad program of experimental activities, which have been involved in the complex R and D program for the Molten Salt Reactor (MSR) - SPHINX (SPent Hot fuel Incinerator by Neutron fluX) concept development in the Czech Republic, there has been a next stage (namely large-scale experimental verification of design inputs by use of MSR-type inserted zones into the existing light water moderated experimental reactor LR-0 called EROS project) started, which will be focused to the experimental verification of the rector physical or neutronic properties of other types of reactor concepts applying molten salts in the role of liquid fuel and/or coolant. This tendency is based on the recently accepted decision of the MSR SSC of GIF to consider for further period of its activity two baseline concepts- fast neutron molten salt reactor non-moderated (FMSR-NM) as a long-term alternative to solid fuelled fast neutron reactors and simultaneously, advanced high temperature reactor (AHTR) with pebble bed type solid fuel cooled by liquid salts. There will be a brief description of the prepared and performed experimental programs in these directions (as well as the preliminary results obtained so far) introduced in the paper. (author)

Hydrodynamic Modelling of Municipal Solid Waste Residues in a Pilot Scale Fluidized Bed Reactor

Directory of Open Access Journals (Sweden)

João Cardoso

2017-11-01

Full Text Available The present study investigates the hydrodynamics and heat transfer behavior of municipal solid waste (MSW gasification in a pilot scale bubbling fluidized bed reactor. A multiphase 2-D numerical model following an Eulerian-Eulerian approach within the FLUENT framework was implemented. User defined functions (UDFs were coupled to improve hydrodynamics and heat transfer phenomena, and to minimize deviations between the experimental and numerical results. A grid independence study was accomplished through comparison of the bed volume fraction profiles and by reasoning the grid accuracy and computational cost. The standard deviation concept was used to determine the mixing quality indexes. Simulated results showed that UDFs improvements increased the accuracy of the mathematical model. Smaller size ratio of the MSW-dolomite mixture revealed a more uniform mixing, and larger ratios enhanced segregation. Also, increased superficial gas velocity promoted the solid particles mixing. Heat transfer within the fluidized bed showed strong dependence on the MSW solid particles sizes, with smaller particles revealing a more effective process.

Experience in utilizing research reactors in Yugoslavia

Energy Technology Data Exchange (ETDEWEB)

Pop-Jordanov, J.; Raisic, N. [Boris Kidric Institute of Nuclear Sciences VINCA, Belgrade (Yugoslavia); Copic, M.; Gabrovsek, Z. [Jozef Stefan Institute Ljubljana (Yugoslavia)

1972-07-01

The nuclear institutes in Yugoslavia possess three research reactors. Since 1958, two heavy-water reactors have been in operation at the 'Boris Kidric' Institute, a zero-power reactor RB and a 6. 5-MW reactor RA. At the Jozef Stefan Institute, a 250-kW TRIGA Mark II reactor has been operating since 1966. All reactors are equipped with the necessary experimental facilities. The main activities based on these reactors are: (1) fundamental research in solid-state and nuclear physics; (2) R and D activities related to nuclear power program; and (3) radioisotope production. In fundamental physics, inelastic neutron scattering and diffraction phenomena are studied by means of the neutron beam tubes and applied to investigations of the structures of solids and liquids. Valuable results are also obtained in n - γ reaction studies. Experiments connected with the fuel -element development program, owing to the characteristics of the existing reactors, are limited to determination of the fuel element parameters, to studies on the purity of uranium, and to a small number of capsule irradiations. All three reactors are also used for the verification of different methods applied in the analysis of power reactors, particularly concerning neutron flux distributions, the optimization of reactor core configurations and the shielding effects. An appreciable irradiation space in the reactors is reserved for isotope production. Fruitful international co-operation has been established in all these activities, on the basis of either bilateral or multilateral arrangements. The paper gives a critical analysis of the utilization of research reactors in a developing country such as Yugoslavia. The investments in and the operational costs of research reactors are compared with the benefits obtained in different areas of reactor application. The impact on the general scientific, technological and educational level in the country is also considered. In particular, an attempt is made ro

Experience in utilizing research reactors in Yugoslavia

International Nuclear Information System (INIS)

Pop-Jordanov, J.; Raisic, N.; Copic, M.; Gabrovsek, Z.

1972-01-01

The nuclear institutes in Yugoslavia possess three research reactors. Since 1958, two heavy-water reactors have been in operation at the 'Boris Kidric' Institute, a zero-power reactor RB and a 6. 5-MW reactor RA. At the Jozef Stefan Institute, a 250-kW TRIGA Mark II reactor has been operating since 1966. All reactors are equipped with the necessary experimental facilities. The main activities based on these reactors are: (1) fundamental research in solid-state and nuclear physics; (2) R and D activities related to nuclear power program; and (3) radioisotope production. In fundamental physics, inelastic neutron scattering and diffraction phenomena are studied by means of the neutron beam tubes and applied to investigations of the structures of solids and liquids. Valuable results are also obtained in n - γ reaction studies. Experiments connected with the fuel -element development program, owing to the characteristics of the existing reactors, are limited to determination of the fuel element parameters, to studies on the purity of uranium, and to a small number of capsule irradiations. All three reactors are also used for the verification of different methods applied in the analysis of power reactors, particularly concerning neutron flux distributions, the optimization of reactor core configurations and the shielding effects. An appreciable irradiation space in the reactors is reserved for isotope production. Fruitful international co-operation has been established in all these activities, on the basis of either bilateral or multilateral arrangements. The paper gives a critical analysis of the utilization of research reactors in a developing country such as Yugoslavia. The investments in and the operational costs of research reactors are compared with the benefits obtained in different areas of reactor application. The impact on the general scientific, technological and educational level in the country is also considered. In particular, an attempt is made ro

UV-A photocatalytic treatment of Legionella pneumophila bacteria contaminated airflows through three-dimensional solid foam structured photocatalytic reactors

Energy Technology Data Exchange (ETDEWEB)

Josset, Sebastien; Hajiesmaili, Shabnam; Begin, Dominique; Edouard, David; Pham-Huu, Cuong [Laboratoire des Materiaux, Surfaces et Procedes pour la Catalyse (LMSPC), European Laboratory for Catalysis and Surface Sciences (ELCASS), CNRS, Strasbourg University, 25 rue Becquerel 67087 Strasbourg (France); Lett, Marie-Claire [Laboratoire de Genetique Moleculaire, Genomique, Microbiologie, CNRS, Strasbourg University, 28, rue Goethe 67083 Strasbourg Cedex (France); Keller, Nicolas, E-mail: nkeller@chimie.u-strasbg.fr [Laboratoire des Materiaux, Surfaces et Procedes pour la Catalyse (LMSPC), European Laboratory for Catalysis and Surface Sciences (ELCASS), CNRS, Strasbourg University, 25 rue Becquerel 67087 Strasbourg (France); Keller, Valerie [Laboratoire des Materiaux, Surfaces et Procedes pour la Catalyse (LMSPC), European Laboratory for Catalysis and Surface Sciences (ELCASS), CNRS, Strasbourg University, 25 rue Becquerel 67087 Strasbourg (France)

2010-03-15

A 3D-structured photocatalytic media was designed for allowing a tubular reactor to work in a traversing-flow mode at low pressure drops with a strong increase in the surface area-to-volume ratio inside the reactor. A protective polysiloxane coating was performed for protecting a structured polyurethane foam and anchoring the active TiO{sub 2} particles. Filled with the 3D-structured solid foam supporting TiO{sub 2} photocatalyst, the reactor could thus take advantages from the static mixer effect and from the low pressure drop resulting from the reticulated foam support. Very efficient decontamination levels towards airborne Legionella pneumophila bacteria were reached in a single-pass test mode.

Fluidized-bed design for ICF reactor blankets using solid-lithium compounds

International Nuclear Information System (INIS)

Sucov, E.W.; Malick, F.S.; Green, L.; Hall, B.O.

1983-01-01

A fluidized-bed concept for blankets of dry or wetted first-wall ICF reactors using solid-lithium compounds is described. The reaction chamber is a right cylinder, 32 m high and 20 m in diameter; the blanket is composed of 36 steel tanks, 32 m high, which carry the sintered Li 2 O particles in the fluidizing helium gas. Each tank has a radial thickness of 2 m which generates a tritium breeding ration (TBR) of 1.27 and absorbs over 98% of the neutron energy; reducing the thickness to 1.2 m produces a TBR of 1.2 and energy absorption of 97% which satisfy the design goals. Calculations of tritium diffusion through the grains and heat removal from the grains showed that neither could be removed by the carrier gas; tritium and heat are therefore removed by removing the grains themselves by varying the helium flow rate. The particles are continuously fed into the bottom of the tanks at 300 0 C and removed at the top at 475 0 C. Tritium and heat extraction are easily and conveniently done outside the reactor

Inulinase production in a packed bed reactor by solid state fermentation.

Science.gov (United States)

Dilipkumar, M; Rajamohan, N; Rajasimman, M

2013-07-01

In this work, production of inulinase was carried out in a packed bed reactor (PBR) under solid state fermentation. Kluyveromyces marxianus var. marxianus was used to produce the inulinase using pressmud as substrate. The parameters like air flow rate, packing density and particle size were optimized using response surface methodology (RSM) to maximize the inulinase production. The optimum conditions for the maximum inulinase production were: air flow rate - 0.82 L/min, packing density - 40 g/L and particle size - 0.0044 mm (mesh - 14/20). At these optimized conditions, the production of inulinase was found to be 300.5 unit/gram of dry substrate (U/gds). Copyright © 2013 Elsevier Ltd. All rights reserved.

Material for shutting down gas cooled nuclear reactors

International Nuclear Information System (INIS)

Jackson, F.

1977-01-01

Some disadvantage of conventional emergency shutdown means for nuclear reactors employing a supply of B steel shot or B powder are mentioned. With regard to B powder it is stated that there is some uncertainty as to whether the powder once dispersed into the core will settle in the active part of the core in sufficient quantities to ensure shutdown. The system described aims to avoid these disadvantages. Pellets are provided comprising a solid neutron poison material and a solid organic substance that remains solid at the relatively low temperature normally expected to prevail in the reactor coolant channel away from the reactor core. The organic substance melts at a higher temperature expected to prevail in the coolant channel within the core., and is adherent on melting to the coolant channel wall and to the solid neutron poison, being thus capable of causing adherence of the latter to the coolant channel wall in the reactor core. The pellets are preferably given a moisture resistant coating to prevent them sticking together and to impart free flowing characteristics. The neutron poison may consist of B, Cd, Gd, or their compounds, and for the coating a suitable polymer may be used. Steel filings may be incorporated in the pellets to aid easy flowing under gravity. Examples of manufacture of the pellets are given. (U.K.)

A side-by-side comparison of two systems of sequencing coupled reactors for anaerobic digestion of the organic fraction of municipal solid waste.

Science.gov (United States)

Poggi-Varaldo, Héctor M; Alzate-Gaviria, Liliana M; Pérez-Hernández, Antonino; Nevarez-Morillón, Virginia G; Rinderknecht-Seijas, Noemí

2005-06-01

The objective of this work was to compare the performance of two laboratory-scale, mesophilic systems aiming at the anaerobic digestion of the organic fraction of municipal solid wastes (OFMSW). The first system consisted of two coupled reactors packed with OFMSW (PBR1.1-PBR1.2) and the second system consisted of an upflow anaerobic sludge bed reactor (UASB) coupled to a packed reactor (UASB2.1-PBR2.2). For the start-up phase, both reactors PBR 1.1 and the UASB 2.1 (also called leading reactors) were inoculated with a mixture of non-anaerobic inocula and worked with leachate and effluent full recirculation, respectively. Once a full methanogenic regime was achieved in the leading reactors, their effluents were fed to the fresh-packed reactors PBR1.2 and PBR2.2, respectively. The leading PBR 1.1 reached its full methanogenic regime after 118 days (Tm, time to achieve methanogenesis) whereas the other leading UASB 2.1 reactor reached its full methanogenesis regime after only 34 days. After coupling the leading reactors to the corresponding packed reactors, it was found that both coupled anaerobic systems showed similar performances regarding the degradation of the OFMSW. Removal efficiencies of volatile solids and cellulose and the methane pseudo-yield were 85.95%, 80.88% and 0.109 NL CH4 g(-1) VS(fed) in the PBR-PBR system; and 88.75%, 82.61% and 0.115 NL CH4 g(-1) VS(fed0 in the UASB-PBR system [NL, normalized litre (273 degrees K, 1 ata basis)]. Yet, the second system UASB-PBR system showed a faster overall start-up.

Progress of decommissioning of Rikkyo reactor in FY2014

International Nuclear Information System (INIS)

Suzuki, M.; Kato, M.; Tanzawa, T.; Kawaguchi, K.; Terasawa, T.; Yamada, Shigeru; Nakai, Masaru

2015-01-01

Institute for Atomic Energy, Rikkyo University, applied in 2012 for changes in the decommissioning plan toward the abolition of the reactor facilities, and received approval. It promoted the decommissioning work of the research reactors in a plan for two years from 2012, conducted the removal of the structure installed in the reactor tank and storage management measures, and implemented the function stop of the disposal facility of liquid waste and the removal of part of them. These procedures achieved the safe storage condition of core internal structure / equipment with relatively high radioactivity due to neutron irradiation. In addition, the maintenance management of partial facilities and equipment that had been maintained in operational conditions had come to be unnecessary. Based on these results, the implementation plan for decommissioning scheduled for 2015-2016 was prepared. The contents of main works are as follows: (1) dismantling and removal of disposal facilities for liquid waste and storage management of subsequently generated radioactive waste in the reactor building control area, (2) storage management of radioactive solid waste of solid waste storage facilities in the reactor building control area, (3) dismantling and removal of solid waste storage facilities that become unnecessary, and (4) release of part of the controlled area associated with the above actions. (A.O.)

Interactions between bacteria and solid surfaces in relation to bacterial transport in porous media

NARCIS (Netherlands)

Rijnaarts, H.H.M.

1994-01-01

Interactions between bacteria and solid surfaces strongly influence the behaviour of bacteria in natural and engineered ecosystems. Many biofilm reactors and terrestrial environments are porous media. The purpose of the research presented in this thesis is to gain a better insight into the

Numerical modeling of disperse material evaporation in axisymmetric thermal plasma reactor

Directory of Open Access Journals (Sweden)

Stefanović Predrag Lj.

2003-01-01

Full Text Available A numerical 3D Euler-Lagrangian stochastic-deterministic (LSD model of two-phase flow laden with solid particles was developed. The model includes the relevant physical effects, namely phase interaction, panicle dispersion by turbulence, lift forces, particle-particle collisions, particle-wall collisions, heat and mass transfer between phases, melting and evaporation of particles, vapour diffusion in the gas flow. It was applied to simulate the processes in thermal plasma reactors, designed for the production of the ceramic powders. Paper presents results of extensive numerical simulation provided (a to determine critical mechanism of interphase heat and mass transfer in plasma flows, (b to show relative influence of some plasma reactor parameters on solid precursor evaporation efficiency: 1 - inlet plasma temperature, 2 - inlet plasma velocity, 3 - particle initial diameter, 4 - particle injection angle a, and 5 - reactor wall temperature, (c to analyze the possibilities for high evaporation efficiency of different starting solid precursors (Si, Al, Ti, and B2O3 powder, and (d to compare different plasma reactor configurations in conjunction with disperse material evaporation efficiency.

Parametric study on vapor-solid-solid growth mechanism of multiwalled carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Shukrullah, S., E-mail: zshukrullah@gmail.com [Center of Innovative Nanostructures and Nanodevices, Universiti Teknologi PETRONAS, 32610, Bandar Seri Iskandar, Perak (Malaysia); Mohamed, N.M. [Center of Innovative Nanostructures and Nanodevices, Universiti Teknologi PETRONAS, 32610, Bandar Seri Iskandar, Perak (Malaysia); Shaharun, M.S. [Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS, 32610, Bandar Seri Iskandar, Perak (Malaysia); Naz, M.Y. [Department of Mechanical Engineering, Universiti Teknologi PETRONAS, 32610, Bandar Seri Iskandar, Perak (Malaysia)

2016-06-15

This study aimed at investigating the effect of the fluidized bed chemical vapor deposition (FBCVD) process parameters on growth mechanism, morphology and purity of the multiwalled carbon nanotubes (MWCNTs). Nanotubes were produced in a vertical FBCVD reactor by catalytic decomposition of ethylene over Al{sub 2}O{sub 3} supported nano-iron catalyst buds at different flow rates. FESEM, TEM, Raman spectroscopy and TGA thermograms were used to elaborate the growth parameters of the as grown MWCNTs. As the growth process was driven by the process temperatures well below the iron-carbon eutectic temperature (1147 °C), the appearance of graphite platelets from the crystallographic faces of the catalyst particles suggested a solid form of the catalyst during CNT nucleation. A vapor-solid-solid (VSS) growth mechanism was predicted for nucleation of MWCNTs with very low activation energy. The nanotubes grown at optimized temperature and ethylene flow rate posed high graphitic symmetry, purity, narrow diameter distribution and shorter inter-layer spacing. In Raman and TGA analyses, small I{sub D}/I{sub G} ratio and residual mass revealed negligible ratios of structural defects and amorphous carbon in the product. However, several structural defects and impurity elements were spotted in the nanotubes grown under unoptimized process parameters. - Graphical abstract: Arrhenius plot of relatively pure MWCNTs grown over Al2O3 supported nano-iron buds. - Highlights: • Vapor–solid–solid growth mechanism of MWCNTs was studied in a vertical FBCVD reactor. • MWCNTs were grown over Al2O3 supported nano-iron buds at very low activation energy. • FBCVD reactor was operated at temperatures well below the iron-carbon eutectic point. • Ideally graphitized structures were obtained at a process temperature of 800 °C. • Tube diameter revealed a narrow distribution of 20–25 nm at the optimum temperature.

Parametric study on vapor-solid-solid growth mechanism of multiwalled carbon nanotubes

International Nuclear Information System (INIS)

Shukrullah, S.; Mohamed, N.M.; Shaharun, M.S.; Naz, M.Y.

2016-01-01

This study aimed at investigating the effect of the fluidized bed chemical vapor deposition (FBCVD) process parameters on growth mechanism, morphology and purity of the multiwalled carbon nanotubes (MWCNTs). Nanotubes were produced in a vertical FBCVD reactor by catalytic decomposition of ethylene over Al_2O_3 supported nano-iron catalyst buds at different flow rates. FESEM, TEM, Raman spectroscopy and TGA thermograms were used to elaborate the growth parameters of the as grown MWCNTs. As the growth process was driven by the process temperatures well below the iron-carbon eutectic temperature (1147 °C), the appearance of graphite platelets from the crystallographic faces of the catalyst particles suggested a solid form of the catalyst during CNT nucleation. A vapor-solid-solid (VSS) growth mechanism was predicted for nucleation of MWCNTs with very low activation energy. The nanotubes grown at optimized temperature and ethylene flow rate posed high graphitic symmetry, purity, narrow diameter distribution and shorter inter-layer spacing. In Raman and TGA analyses, small I_D/I_G ratio and residual mass revealed negligible ratios of structural defects and amorphous carbon in the product. However, several structural defects and impurity elements were spotted in the nanotubes grown under unoptimized process parameters. - Graphical abstract: Arrhenius plot of relatively pure MWCNTs grown over Al2O3 supported nano-iron buds. - Highlights: • Vapor–solid–solid growth mechanism of MWCNTs was studied in a vertical FBCVD reactor. • MWCNTs were grown over Al2O3 supported nano-iron buds at very low activation energy. • FBCVD reactor was operated at temperatures well below the iron-carbon eutectic point. • Ideally graphitized structures were obtained at a process temperature of 800 °C. • Tube diameter revealed a narrow distribution of 20–25 nm at the optimum temperature.

Studies on solid-state physics carried out with the Saclay reactor (1962)

International Nuclear Information System (INIS)

Herpin, A.

1962-01-01

This paper deals only with solid-state physics experiments carried out on outgoing beams: rather than giving a general review of the work performed, if refers to only a few of the most important studies or those nearest completion. These are being made with the experimental beams of the two Saclay reactors EL-2, with a central flux of 10 13 n/cm 2 , and - since 1958 - EL-3, whose central flux is equal ta 10 14 n/cm 2 . The experiments are being carried out by two separate groups of physicists, employing different techniques, namely neutron diffraction using a crystal spectrometer, and inelastic scattering using a time-of-flight spectrometer. (author) [fr

Measurement of Narora reactor building relative settlement

International Nuclear Information System (INIS)

Deo, P.M.; Pande, K.C.; Patwardhan, H.S.

1977-01-01

The civil construction of the reactor building of Narora Atomic Power Project has a special problem. The stability of the structure is liable to settlement as this location falls in seismic zone. To obviate the possibility of large scale unequal settlements, the reactor building is founded on a 4 meter thick rigid raft concreted in three layers, at a depth of 13 meters below ground. Stainless steel tanks will be embedded at 17 locations to measure relative settlements. The relative elevation difference will be detected by electrical probes when the water level in any one of the tanks touches the tip of the probes. The design envisages a maximum permissible unequal settlements of about 10 mm. over a period of 20 years. (K.B.)

Age-related degradation of boiling water reactor vessel internals

International Nuclear Information System (INIS)

Ware, A.G.; Shah, V.N.

1992-01-01

Researchers at the Idaho National Engineering Laboratory performed an assessment of the aging of the reactor internals in boiling water reactors (BWRs), and identified the unresolved technical issues related to the degradation of these components. The overall life-limiting mechanism is intergranular stress corrosion cracking (IGSCC). Irradiation-assisted stress corrosion cracking, fatigue, and thermal aging embrittlement are other potential degradation mechanisms. Several failures in BWR internals have been caused by a combination of factors such as environment, high residual or preload stresses, and flow-induced vibration. The ASME Code Section XI in-service inspection requirements are insufficient for detecting aging-related degradation at many locations in reactor internals. Many of the potential locations for IGSCC or fatigue are not accessible for inspection. (orig.)

Performance Monitoring for Nuclear Safety Related Instrumentation at PUSPATI TRIGA Reactor (RTP)

International Nuclear Information System (INIS)

Zareen Khan Abdul Jalil Khan; Ridzuan Abdul Mutalib; Mohd Sabri Minhat

2015-01-01

The Reactor TRIGA PUSPATI (RTP) at Malaysia Nuclear Agency is a TRIGA Mark II type reactor and pool type cooled by natural circulation of light water. This paper describe on performance monitoring for nuclear safety related instrumentation in TRIGA PUSPATI Reactor (RTP) of based on various parameter of reactor safety instrument channel such as log power, linear power, Fuel temperature, coolant temperature will take into consideration. Methodology of performance on estimation and monitoring is to evaluate and analysis of reactor parameters which is important of reactor safety and control. And also to estimate power measurement, differential of log and linear power and fuel temperature during reactor start-up, operation and shutdown .This study also focus on neutron power fluctuation from fission chamber during reactor start-up and operation. This work will present result of performance monitoring from RTP which indicated the safety parameter identification and initiate safety action on crossing the threshold set point trip. Conclude that performance of nuclear safety related instrumentation will improved the reactor control and safety parameter during reactor start-up, operation and shutdown. (author)

Effect of hydraulic retention time and sludge recirculation on greenhouse gas emission and related microbial communities in two-stage membrane bioreactor treating solid waste leachate.

Science.gov (United States)

Nuansawan, Nararatchporn; Boonnorat, Jarungwit; Chiemchaisri, Wilai; Chiemchaisri, Chart

2016-06-01

Methane (CH4) and nitrous oxide (N2O) emissions and responsible microorganisms during the treatment of municipal solid waste leachate in two-stage membrane bioreactor (MBR) was investigated. The MBR system, consisting of anaerobic and aerobic stages, were operated at hydraulic retention time (HRT) of 5 and 2.5days in each reactor under the presence and absence of sludge recirculation. Organic and nitrogen removals were more than 80% under all operating conditions during which CH4 emission were found highest under no sludge recirculation condition at HRT of 5days. An increase in hydraulic loading resulted in a reduction in CH4 emission from anaerobic reactor but an increase from the aerobic reactor. N2O emission rates were found relatively constant from anaerobic and aerobic reactors under different operating conditions. Diversity of CH4 and N2O producing microorganisms were found decreasing when hydraulic loading rate to the reactors was increased. Copyright © 2016 Elsevier Ltd. All rights reserved.

The SoLid experiment

Science.gov (United States)

Kalousis, L. N.; SoLid Collaboration

2017-09-01

The SoLid experiment is a short-baseline project, probing the disappearance of reactor antineutrinos using a novel detector design. Installed at a very short distance of ˜ 5.5 - 10 m from the BR2 research reactor at SCK·CEN in Mol (Belgium) it will be able to search for active-to-sterile neutrino oscillations, exploring most of the allowed parameter region. SoLid will make use of a highly segmented detector, built from 5 cm PVT cubes, interleaved with 6LiF:ZnS(Ag) screens, and read out by optical fibers and Silicon Photomultipliers (SiPMs). The detector granularity allows for the localization of the positron and neutron signals from antineutrino interactions and the robust neutron identification capabilities, offered by the 6LiF:ZnS(Ag) inorganic scintillator, provide background suppression to an unparalleled level. This paper reviews the experimental layout and current status of SoLid. Emphasis is put on the challenges one faces towards this measurement, focusing on the decisions and strategy adapted by the SoLid collaboration. The analysis scheme and the details of the oscillation framework are also presented, highlighting the sensitivity contour and physics potential of SoLid. Finally, other physics topics, such as, reactor monitoring or measurement of the 235U spectrum are also covered.

Comparison of the microbial communities in solid-state anaerobic digestion (SS-AD) reactors operated at mesophilic and thermophilic temperatures.

Science.gov (United States)

Li, Yueh-Fen; Nelson, Michael C; Chen, Po-Hsu; Graf, Joerg; Li, Yebo; Yu, Zhongtang

2015-01-01

The microbiomes involved in liquid anaerobic digestion process have been investigated extensively, but the microbiomes underpinning solid-state anaerobic digestion (SS-AD) are poorly understood. In this study, microbiome composition and temporal succession in batch SS-AD reactors, operated at mesophilic or thermophilic temperatures, were investigated using Illumina sequencing of 16S rRNA gene amplicons. A greater microbial richness and evenness were found in the mesophilic than in the thermophilic SS-AD reactors. Firmicutes accounted for 60 and 82 % of the total Bacteria in the mesophilic and in the thermophilic SS-AD reactors, respectively. The genus Methanothermobacter dominated the Archaea in the thermophilic SS-AD reactors, while Methanoculleus predominated in the mesophilic SS-AD reactors. Interestingly, the data suggest syntrophic acetate oxidation coupled with hydrogenotrophic methanogenesis as an important pathway for biogas production during the thermophilic SS-AD. Canonical correspondence analysis (CCA) showed that temperature was the most influential factor in shaping the microbiomes in the SS-AD reactors. Thermotogae showed strong positive correlation with operation temperature, while Fibrobacteres, Lentisphaerae, Spirochaetes, and Tenericutes were positively correlated with daily biogas yield. This study provided new insight into the microbiome that drives SS-AD process, and the findings may help advance understanding of the microbiome in SS-AD reactors and the design and operation of SS-AD systems.

Pellet acceleration studies relating to the refuelling of a steady-state fusion reactor

International Nuclear Information System (INIS)

Dimock, D.; Jensen, K.; Jensen, V.O.; Joergensen, L.W.; Pecseli, H.L.; Soerensen, H.; Oester, F.

1975-11-01

Several methods for refuelling a steady state-fusion reactor have been proposed, and the pellet method seems advantageous if the pellet can be accelerated to the necessary velocity. A study group was formed to analyze this acceleration problem. Two pellet velocity values were considered: 10 4 m/s and 300 m/s. A pellet velocity of 10 4 m/s may be suitable in the case of a reactor, whereas 300 m/s is believed to be a reasonable velocity at which to perform realistic ablation experiments in the near future. A pneumatic acceleration method was found promising. The pressure is either supplied separately or by evaporation of a part of the pellet. In the latter case, a spark behind the pellet should provide the evoporation and the necessary heating of the driving gas. A preliminary test at room temperature with pellets made of beeswax (the density being ten times that of solid hydrogen, and plastic properties similar to those of solid hydrogen) resulted in a pellet velocity of 100 m/s at a modest value of the energy supplied to the spark. (Auth.)

Combustion flame-plasma hybrid reactor systems, and chemical reactant sources

Science.gov (United States)

Kong, Peter C

2013-11-26

Combustion flame-plasma hybrid reactor systems, chemical reactant sources, and related methods are disclosed. In one embodiment, a combustion flame-plasma hybrid reactor system comprising a reaction chamber, a combustion torch positioned to direct a flame into the reaction chamber, and one or more reactant feed assemblies configured to electrically energize at least one electrically conductive solid reactant structure to form a plasma and feed each electrically conductive solid reactant structure into the plasma to form at least one product is disclosed. In an additional embodiment, a chemical reactant source for a combustion flame-plasma hybrid reactor comprising an elongated electrically conductive reactant structure consisting essentially of at least one chemical reactant is disclosed. In further embodiments, methods of forming a chemical reactant source and methods of chemically converting at least one reactant into at least one product are disclosed.

Recent progress in safety-related applications of reactor noise analysis

International Nuclear Information System (INIS)

Hirota, Jitsuya; Shinohara, Yoshikuni; Saito, Keiichi

1982-01-01

Recent progress in safety-related applications of reactor noise analysis is reviewed, mainly referring to various papers presented at the Third Specialists' Meeting on Reactor Noise (SMORN-III) held in Tokyo in 1981. Advances in application of autoregressive model, coherence analysis and pattern recognition technique are significant since SMORN-II in 1977. Development of reactor diagnosis systems based on noise analysis is in progress. Practical experiences in the safety-related applications to power plants are being accumulated. Advances in quantitative monitoring of vibration of internal structures in PWR and diagnosis of core stability and control system characteristics in BWR are notable. Acoustic methods are also improved to detect sodium boiling in LMFBR. The Reactor Noise Analysis Benchmark Test performed by Japan in connection with SMORN-III is successful so that it is possible to proceed to the second stage of the benchmark test. (author)

Molecular ecology of anaerobic reactor systems

DEFF Research Database (Denmark)

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

2003-01-01

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

Method and apparatus for treating liquid contaminated with radioactive particulate solids

International Nuclear Information System (INIS)

Hirs, G.

1976-01-01

A method and apparatus reduces the amount of radioactive solids resulting from the filtration of particulate contaminants from liquid in a nuclear reactor plant. A filtration system includes a pre-filter comprising a sheet filter medium through which the reactor liquid passes to remove relatively large particulate contaminants for storage or disposal. The reactor liquid is then passed through a bed of granular filter medium to accumulate substantially all the previously non-filtered contaminants and thereby provide a clarified liquid suitable for reuse in the reactor. Backwash liquid is flowed through the granular filter bed to remove and entrain the accumulated contaminants into a slurry which is received by a reservoir where the slurry is maintained quiescently to settle the contaminants. Removal of liquid from the reservoir concentrates the contaminants for storage or further processing, without the necessity of large quantities of filter aids that would increase the quantity of storage-requiring contaminated solids

Hydrogen problems related to reactor accidents

International Nuclear Information System (INIS)

Bujor, A.

1993-09-01

At reactor accidents, the combustion of hydrogen causes pressure and temperature transients which pose supplementary loads in containment. In certain conditions, they could reach hazardous levels and impair the integrity of the containment and the operability of the safety systems. The mechanisms of chemical reactions specific for the hydrogen-oxygen system are presented. Conditions in which combustion can occur and the various combustion modes, including the transition to detonation are also described. The related safety aspects and mitigation methods are discussed. Examples for particular applications and safety approaches for various types of reactors, included those promoted for the advanced reactors are also given. Presentation of the experimental research completed at AECL-Research, Whiteshell Laboratory is given, where the multi-point ignition effects for constant volume and for vented combustion of dry hydrogen-air mixtures in various geometries have been investigated. Various aspects of modelling and simulation of hydrogen combustion are discussed. The adaptations and the new models implemented in the codes VENT and CONTAIN, aimed to widen the simulation capabilities of hydrogen combustion models are described. The capabilities and limitations of the modelling assumptions of these two codes are also evaluated. (EG) (11 tabs., 39 ills., 82 refs.)

Comparative Analysis of Performance and Microbial Characteristics Between High-Solid and Low-Solid Anaerobic Digestion of Sewage Sludge Under Mesophilic Conditions.

Science.gov (United States)

Lu, Qin; Yi, Jing; Yang, Dianhai

2016-01-01

High-solid anaerobic digestion of sewage sludge achieves highly efficient volatile solid reduction, and production of volatile fatty acid (VFA) and methane compared with conventional low-solid anaerobic digestion. In this study, the potential mechanisms of the better performance in high-solid anaerobic digestion of sewage sludge were investigated by using 454 high-throughput pyrosequencing and real-time PCR to analyze the microbial characteristics in sewage sludge fermentation reactors. The results obtained by 454 high-throughput pyrosequencing revealed that the phyla Chloroflexi, Bacteroidetes, and Firmicutes were the dominant functional microorganisms in high-solid and low-solid anaerobic systems. Meanwhile, the real-time PCR assays showed that high-solid anaerobic digestion significantly increased the number of total bacteria, which enhanced the hydrolysis and acidification of sewage sludge. Further study indicated that the number of total archaea (dominated by Methanosarcina) in a high-solid anaerobic fermentation reactor was also higher than that in a low-solid reactor, resulting in higher VFA consumption and methane production. Hence, the increased key bacteria and methanogenic archaea involved in sewage sludge hydrolysis, acidification, and methanogenesis resulted in the better performance of high-solid anaerobic sewage sludge fermentation.

Safety-related parameters for the MAPLE research reactor and a comparison with the IAEA generic 10-MW research reactor

International Nuclear Information System (INIS)

Carlson, P.A.; Lee, A.G.; Smith, H.J.; Ellis, R.J.

1989-07-01

A summary is presented of some of the principle safety-related physics parameters for the MAPLE Research Reactor, and a comparison with the IAEA Generic 10-MW Reactor is given. This provides a means to assess the operating conditions and fuelling requirements for safe operation of the MAPLE Research Reactor under accepted standards

arXiv Performance of a full scale prototype detector at the BR2 reactor for the SoLid experiment

CERN Document Server

Abreu, Y.; Arnold, L.; Ban, G.; Beaumont, W.; Bongrand, M.; Boursette, D.; Castle, B.C.; Clark, K.; Coupé, B.; Cussans, D.; De Roeck, A.; D'Hondt, J.; Durand, D.; Fallot, M.; Ghys, L.; Giot, L.; Guillon, B.; Ihantola, S.; Janssen, X.; Kalcheva, S.; Kalousis, L.N.; Koonen, E.; Labare, M.; Lehaut, G.; Manzanillas, L.; Mermans, J.; Michiels, I.; Moortgat, C.; Newbold, D.; Park, J.; Pestel, V.; Petridis, K.; Piñera, I.; Pommery, G.; Popescu, L.; Pronost, G.; Rademacker, J.; Ryckbosch, D.; Ryder, N.; Saunders, D.; Schune, M.-H.; Simard, L.; Vacheret, A.; Van Dyck, S.; Van Mulders, P.; van Remortel, N.; Vercaemer, S.; Verstraeten, M.; Weber, A.; Yermia, F.

2018-05-03

The SoLid collaboration has developed a new detector technology to detect electron anti-neutrinos at close proximity to the Belgian BR2 reactor at surface level. A 288 kg prototype detector was deployed in 2015 and collected data during the operational period of the reactor and during reactor shut-down. Dedicated calibration campaigns were also performed with gamma and neutron sources. This paper describes the construction of the prototype detector with a high control on its proton content and the stability of its operation over a period of several months after deployment at the BR2 reactor site. All detector cells provide sufficient light yields to achieve a target energy resolution of better than 20%/√E(MeV). The capability of the detector to track muons is exploited to equalize the light response of a large number of channels to a precision of 3% and to demonstrate the stability of the energy scale over time. Particle identification based on pulse-shape discrimination is demonstrated with calibration so...

Nuclear reactor apparatus

International Nuclear Information System (INIS)

Braun, H.E.; Bonnet, H.P.

1978-01-01

The reactor and its containment, instead of being supported on a solid concrete pad, are supported on a truss formed of upper and lower reinforced horizontal plates and vertical walls integrated into a rigid structure. The plates and walls from chambers within which the auxiliary components of the reactor, such as valves, pumping equipment and various tanks, are disposed. Certain of the chambers are also access passages for personnel, pipe chases, valve chambers and the like. In particular the truss includes an annular chamber. This chamber is lined and sealed by a corrosion-resistant liner and contains coolant and serves as a refueling cooling storage tank. This tank is directly below the primary-coolant conductor loops which extend from the reactor above the upper plate. The upper plate includes a sump connected to the tank through which coolant flows into the tank in the event of the occurrence of a loss-of-coolant accident. The truss extends beyond the containment and has chambers in the extending annulus. Pumps for circulating the coolant between the refueling coolant storage tank and the reactor are provided in certain of these chambers. The pumps are connected to the reactor by relatively short coolant conductors. Access to these pumps is readily afforded through hatches in the extending annulus

Studies on solid-state physics carried out with the Saclay reactor (1962); Etudes de physique du solide realisees a la pile de Saclay (1962)

Energy Technology Data Exchange (ETDEWEB)

Herpin, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1962-07-01

This paper deals only with solid-state physics experiments carried out on outgoing beams: rather than giving a general review of the work performed, if refers to only a few of the most important studies or those nearest completion. These are being made with the experimental beams of the two Saclay reactors EL-2, with a central flux of 10{sup 13} n/cm{sup 2}, and - since 1958 - EL-3, whose central flux is equal ta 10{sup 14} n/cm{sup 2}. The experiments are being carried out by two separate groups of physicists, employing different techniques, namely neutron diffraction using a crystal spectrometer, and inelastic scattering using a time-of-flight spectrometer. (author) [French] Cet expose ne relate que des experiences de physique du solide faites sur des faisceaux sortis; plutot que de donner une revue de l'ensemble des travaux effectues, on ne cite que quelques etudes que l'on peut considerer comme plus essentielles ou mieux achevees. On utilise les faisceaux experimentaux des deux piles de Saclay, EL-2 dont le flux au centre est de 10{sup 13}n/cm{sup 2} et, depuis 1958, EL-3 pour laquelle il est egal a 10{sup 14} n/cm{sup 2}. Les experiences sont realisees par deux groupes de physiciens distincts, employant des techniques differentes, la diffraction des neutrons qui utilise un spectrometre a cristal, et la diffusion inelastique avec un spectrometre a temps de vol. (auteur)

IAEA Activities in the Area of Fast Reactors and Related Fuels and Fuel Cycles

International Nuclear Information System (INIS)

Monti, S.; Basak, U.; Dyck, G.; Inozemtsev, V.; Toti, A.; Zeman, A.

2013-01-01

Summary: • The IAEA role to support fast reactors and associated fuel cycle development programmes; • Main IAEA activities on fast reactors and related fuel and fuel cycle technology; • Main IAEA deliverables on fast reactors and related fuel and fuel cycle technology

Diversity and dynamics of dominant and rare bacterial taxa in replicate sequencing batch reactors operated under different solids retention time

KAUST Repository

Bagchi, Samik

2014-10-19

In this study, 16S rRNA gene pyrosequencing was applied in order to provide a better insight on the diversity and dynamics of total, dominant, and rare bacterial taxa in replicate lab-scale sequencing batch reactors (SBRs) operated at different solids retention time (SRT). Rank-abundance curves showed few dominant operational taxonomic units (OTUs) and a long tail of rare OTUs in all reactors. Results revealed that there was no detectable effect of SRT (2 vs. 10 days) on Shannon diversity index and OTU richness of both dominant and rare taxa. Nonmetric multidimensional scaling analysis showed that the total, dominant, and rare bacterial taxa were highly dynamic during the entire period of stable reactor performance. Also, the rare taxa were more dynamic than the dominant taxa despite expected low invasion rates because of the use of sterile synthetic media.

Study of the obtainment of Mo{sub 2}C by gas-solid reaction in a fixed and rotary bed reactor; Estudo da obtencao de Mo{sub 2}C por reacao gas-solido em reator de leito fixo e rotativo

Energy Technology Data Exchange (ETDEWEB)

Araujo, C.P.B. de; Souza, C.P. de; Souto, M.V.M.; Barbosa, C.M.; Frota, A.V.V.M., E-mail: cpbaraujo@gmail.com [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

2016-07-01

Carbides' synthesis via gas-solid reaction overcomes many of the difficulties found in other processes, requiring lower temperatures and reaction times than traditional metallurgic routes, for example. In carbides' synthesis in fixed bed reactors (FB) the solid precursor is permeated by the reducing/carburizing gas stream forming a packed bed without mobility. The use of a rotary kiln reactor (RK) adds a mixing character to this process, changing its fluid-particle dynamics. In this work ammonium molybdate was subjected to carbo-reduction reaction (CH4 / H2) in both reactors under the same gas flow (15L / h) and temperature (660 ° C) for 180 minutes. Complete conversion was observed Mo2C (dp = 18.9nm modal particles sizes' distribution) in the fixed bed reactor. In the RK reactor this conversion was only partial (∼ 40%) and Mo2C and MoO3 (34nm dp = bimodal) could be observed on the produced XRD pattern. Partial conversion was attributed to the need to use higher solids loading in the reactor CR (50% higher) to avoid solids to centrifuge. (author)

Engineering reactors for catalytic reactions

Indian Academy of Sciences (India)

126, No. 2, March 2014, pp. 341–351. c Indian Academy of Sciences. ... enhancement was realized by catalyst design, appropriate choice of reactor, better injection and .... Gas–liquid and liquid–solid transport processes in catalytic reactors.5.

Management of research reactor; dynamic characteristics analysis for reactor structures related with vibration of HANARO fuel assembly

Energy Technology Data Exchange (ETDEWEB)

Ahn, Chang Kee; Shim, Joo Sup [Shinwa Technology Information, Seoul (Korea)

2001-04-01

The objective of this study is to deduce the dynamic correlation between the fuel assembly and the reactor structure. Dynamic characteristics analyses for reactor structure related with vibration of HANARO fuel assembly have been performed For the dynamic characteristic analysis, the in-air models of the round and hexagonal flow tubes, 18-element and 36-element fuel assemblies, and reactor structure were developed. By calculating the hydrodynamic mass and distributing it on the in-air models, the in-water models of the flow tubes, the fuel assemblies, and the reactor structure were developed. Then, modal analyses for developed in-air and in-water models have been performed. Especially, two 18-element fuel assemblies and three 36-element fuel assemblies were included in the in-water reactor models. For the verification of the modal analysis results, the natural frequencies and the mode shapes of the fuel assembly were compared with those obtained from the experiment. Finally the analysis results of the reactor structure were compared with them performed by AECL Based on the reactor model without PCS piping, the in-water reactor model including the fuel assemblies was developed, and its modal analysis was performed. The analysis results demonstrate that there are no resonance between the fuel assembly and the reactor structures. 26 refs., 419 figs., 85 tabs. (Author)

SoLid: An innovative anti-neutrino detector for searching oscillations at the SCK•CEN BR2 reactor

Science.gov (United States)

Abreu, Yamiel; SoLid Collaboration

2017-02-01

The SoLid experiment intends to search for active-to-sterile anti-neutrino oscillations at a very short baseline from the SCK•CEN BR2 research reactor (Mol, Belgium). A novel detector approach to measure reactor anti-neutrinos was developed based on an innovative sandwich of composite polyvinyl-toluene and 6LiF:ZnS(Ag) scintillators. The system is highly segmented and read out by a network of wavelength shifting fibers and SiPM. High experimental sensitivity can be achieved compared to other standard technologies thanks to the combination of high granularity, good neutron-gamma discrimination using 6LiF:ZnS(Ag) scintillator and precise localisation of the Inverse Beta Decay products. This technology can be considered as a new generation of an anti-neutrino detector. This compact system requires limited passive shielding and relies on spatial topology to determine the different classes of backgrounds. We will describe the principle of detection and the detector design. Particular focus on the neutron discrimination will be made, as well as on the capability to use cosmic muons for channel equalisation and energy calibration. The performance of the first 288 kg SoLid module (SM1), based on the data taken at BR2 from February to September 2015, will be presented. We will conclude with the next phase, which will start in 2016, and the future plans of the experiment.

TOKOPS: Tokamak Reactor Operations Study: The influence of reactor operations on the design and performance of tokamaks with solid-breeder blankets: Final report

International Nuclear Information System (INIS)

Conn, R.W.; Ghoniem, N.M.; Firestone, M.A.

1986-09-01

Reactor system operation and procedures have a profound impact on the conception and design of power plants. These issues are studied here using a model tokamak system employing a solid-breeder blanket. The model blanket is one which has evolved from the STARFIRE and BCSS studies. The reactor parameters are similar to those characterizing near-term fusion engineering reactors such as INTOR or NET (Next European Tokamak). Plasma startup, burn analysis, and methods for operation at various levels of output power are studied. A critical, and complicating, element is found to be the self-consistent electromagnetic response of the system, including the presence of the blanket and the resulting forces and loadings. Fractional power operation, and the strategy for burn control, is found to vary depending on the scaling law for energy confinement, and an extensive study is reported. Full-power reactor operation is at a neutron wall loading pf 5 MW/m 2 and a surface heat flux of 1 MW/m 2 . The blanket is a pressurized steel module with bare beryllium rods and low-activation HT-9-(9-C-) clad LiAlO 2 rods. The helium coolant pressure is 5 MPa, entering the module at 297 0 C and exiting at 550 0 C. The system power output is rated at 1000 MW(e). In this report, we present our findings on various operational scenarios and their impact on system design. We first start with the salient aspects of operational physics. Time-dependent analyses of the blanket and balance of plant are then presented. Separate abstracts are included for each chapter

Fischer-Tropsch Slurry Reactor modeling

Energy Technology Data Exchange (ETDEWEB)

Soong, Y.; Gamwo, I.K.; Harke, F.W. [Pittsburgh Energy Technology Center, PA (United States)] [and others

1995-12-31

This paper reports experimental and theoretical results on hydrodynamic studies. The experiments were conducted in a hot-pressurized Slurry-Bubble Column Reactor (SBCR). It includes experimental results of Drakeol-10 oil/nitrogen/glass beads hydrodynamic study and the development of an ultrasonic technique for measuring solids concentration. A model to describe the flow behavior in reactors was developed. The hydrodynamic properties in a 10.16 cm diameter bubble column with a perforated-plate gas distributor were studied at pressures ranging from 0.1 to 1.36 MPa, and at temperatures from 20 to 200{degrees}C, using a dual hot-wire probe with nitrogen, glass beads, and Drakeol-10 oil as the gas, solid, and liquid phase, respectively. It was found that the addition of 20 oil wt% glass beads in the system has a slight effect on the average gas holdup and bubble size. A well-posed three-dimensional model for bed dynamics was developed from an ill-posed model. The new model has computed solid holdup distributions consistent with experimental observations with no artificial {open_quotes}fountain{close_quotes} as predicted by the earlier model. The model can be applied to a variety of multiphase flows of practical interest. An ultrasonic technique is being developed to measure solids concentration in a three-phase slurry reactor. Preliminary measurements have been made on slurries consisting of molten paraffin wax, glass beads, and nitrogen bubbles at 180 {degrees}C and 0.1 MPa. The data show that both the sound speed and attenuation are well-defined functions of both the solid and gas concentrations in the slurries. The results suggest possibilities to directly measure solids concentration during the operation of an autoclave reactor containing molten wax.

First results of the deployment of a SoLid detector module at the SCK•CEN BR2 reactor

Science.gov (United States)

Ryder, N.

The SoLid experiment aims to resolve the reactor neutrino anomaly by searching for electron-to-sterile anti-neutrino oscillations. The search will be performed between 5.5 and 10 m from the highly enriched uranium core of the BR2 reactor at SCK-CEN. The experiment utilises a novel approach to anti-neutrino detection based on a highly segmented, composite scintillator detector design. High experimental sensitivity can be achieved using a combination of high neutron-gamma discrimination using 6 LiF:ZnS(Ag) and precise localisation of the inverse beta decay products. This compact detector system requires limited passive shielding as it relies on spacial topology to determine the different classes of backgrounds. The first full scale, 288 kg, detector module was deployed at the BR2 reactor in November 2014. A phased three tonne experimental deployment will begin in the second half of 2016, allowing a precise search for oscillations that will resolve the reactor anomaly using a three tonne detector running for three years. In this talk the novel detector design is explained and initial detector performance results from the module level deployment are presented along with an estimation of the physics reach of the next phase.

Thermal pretreatment of the solid fraction of manure: Impact on the biogas reactor performance and microbial community

DEFF Research Database (Denmark)

Mladenovska, Z; Hartmann, H.; Kvist, T.

2006-01-01

Application of thermal treatment at 100-140 degrees C as a pretreatment method prior to anaerobic digestion of a mixture of cattle and swine manure was investigated. In a batch test, biogasification of manure with thermally pretreated solid fraction proceeded faster and resulted in the increase...... of methane yield. The performances of two thermophilic continuously stirred tank reactors (CSTR) treating manure with solid fraction pretreated for 40 minutes at 140 degrees C and non-treated manure were compared. The digester fed with the thermally pretreated manure had a higher methane productivity...... and butyrate - was low. The kinetic parameters of the VFA conversion revealed a reduced affinity of the microbial community from the CSTR fed with thermally pre-treated manure for acetate, propionate and butyrate. The bacterial and archaeal populations identified by t-RLFP analysis of 16S rRNA genes were found...

First experience with the new solid methane moderator at the IBR-2 reactor

International Nuclear Information System (INIS)

Beliakov, A.A.; Shabalin, E.P.; Tretyakov, I.T.

2001-01-01

In the 1999 Fall the solid methane moderator (CM) has been installed and tested at full power at the IBR-2 pulsed reactor. Its main features are a beryllium reflector and a light water premoderator. Radiation load on the methane was three times as much as that of IPNS facility, namely, 0.1 W/g. Effects of temperature, operation time, concentration of a hydrogen scavenger, and annealing procedure on both neutron and service performances were studied. Maximum operation time of a newly loaded portion of methane was 4 days. In this time around 30% of methane is transformed into hydrogen, ethane, and high molecular hydrocarbons, and yet no deterioration in cold neutron intensity was detected. Among new knowledge, the most important are two facts observed: two-fold decrease in hydrogen formation rate when methane is poisoned with 2.5% to 5% of ethylene, and low formation rate of solid, inremovable products of radiolysis - (1.5/3)10 -7 g/J, which means that after 10 years of operation the methane chamber will be filled with only 100 g of residue. Gain of factor 20 in cold neutron flux was obtained as compared to the routine grooved light water moderator. Presently, it is the highest among the intense pulsed neutron sources. (author)

Contribution to the use of a solid moderator gas reactor, for naval propulsion

International Nuclear Information System (INIS)

Pheline, J.; Gautier, A.

1960-01-01

In this contribution, the authors discuss works performed in France for the development of nuclear propulsion in merchant ships, notably for an oil tanker of 50.000 tons with 17 knot speed, i.e. a 20.000 Hp engine with an energy produced by a 60 MW gas reactor with a solid moderator and comprising 400 channels loaded with uranium oxide enriched ay 2.8 per cent and sheathed with a refractory alloy. The authors discuss the possible materials for the moderator, the heat transfer medium, the sheath, the fuel and the structures, and report technological studies (mechanical tests, irradiation tests) performed to investigate material properties and their behaviour in operation conditions. They report tests performed to investigate core structure characteristics with respect to neutrons. They finally briefly present a prototype

Perspectives and possibilities for solid state physcis investigations at thhe pulsed reactor IBR-2 of the JINR Dubna

International Nuclear Information System (INIS)

Feldmann, K.; Frauenheim, T.; Lauckner, J.; Weniger, J.; Muehle, E.

1982-02-01

Three time-of-flight spectrometers (spectrometer of high resolution NSWR, spectrometer of inverted geometry KDSOG and spectrometer of polarized neutrons SPN-1) are presented, which will be working at the pulsed IBR-2 reactor of the JINR Dubna. Considering the parameters and the special methods of measurement of these spectrometers, the possibilities of their applications for the investigations of structural, magnetic and electronic properties of solids by means of elastic, inelastic and quasielastic neutron scattering are discussed. (author)

Status report of Indonesian research reactor

International Nuclear Information System (INIS)

Arbie, B.; Supadi, S.

1992-01-01

A general description of three Indonesian research reactor, its irradiation facilities and its future prospect are described. Since 1965 Triga Mark II 250 KW Bandung, has been in operation and in 1972 the design powers were increased to 1000 KW. Using core grid form Triga 250 KW BATAN has designed and constructed Kartini Reactor in Yogyakarta which started its operation in 1979. Both of this Triga type reactors have served a wide spectrum of utilization such as training manpower in nuclear engineering, radiochemistry, isotope production and beam research in solid state physics. Each of this reactor have strong cooperation with Bandung Institute of Technology at Bandung and Gajah Mada University at Yogyakarta which has a faculty of Nuclear Engineering. Since 1976 the idea to have high flux reactor has been foreseen appropriate to Indonesian intention to prepare infrastructure for nuclear industry for both energy and non-energy related activities. The idea come to realization with the first criticality of RSG-GAS (Multipurpose Reactor G.A. Siwabessy) in July 1987 at PUSPIPTEK Serpong area. It is expected that by early 1992 the reactor will reached its full power of 30 MW and by end 1992 its expected that irradiation facilities will be utilized in the future for nuclear scientific and engineering work. (author)

SoLid: An innovative anti-neutrino detector for searching oscillations at the SCK• CEN BR2 reactor

Energy Technology Data Exchange (ETDEWEB)

Abreu, Yamiel, E-mail: yamiel.abreu@uantwerpen.be

2017-02-11

The SoLid experiment intends to search for active-to-sterile anti-neutrino oscillations at a very short baseline from the SCK• CEN BR2 research reactor (Mol, Belgium). A novel detector approach to measure reactor anti-neutrinos was developed based on an innovative sandwich of composite polyvinyl-toluene and {sup 6}LiF:ZnS(Ag) scintillators. The system is highly segmented and read out by a network of wavelength shifting fibers and SiPM. High experimental sensitivity can be achieved compared to other standard technologies thanks to the combination of high granularity, good neutron–gamma discrimination using {sup 6}LiF:ZnS(Ag) scintillator and precise localisation of the Inverse Beta Decay products. This technology can be considered as a new generation of an anti-neutrino detector. This compact system requires limited passive shielding and relies on spatial topology to determine the different classes of backgrounds. We will describe the principle of detection and the detector design. Particular focus on the neutron discrimination will be made, as well as on the capability to use cosmic muons for channel equalisation and energy calibration. The performance of the first 288 kg SoLid module (SM1), based on the data taken at BR2 from February to September 2015, will be presented. We will conclude with the next phase, which will start in 2016, and the future plans of the experiment.

Cellulase production by Trichoderma harzianum in static and mixed solid-state fermentation reactors under nonaseptic conditions

Energy Technology Data Exchange (ETDEWEB)

Deschamps, F.; Giuliano, C.; Asther, M.; Huet, M.C.; Roussos, S.

1985-09-01

Cellulase production from lignocellulosic materials was studied in solid-state cultivation by both static and mixed techniques under nonaseptic conditions. The effects of fermentation conditions, such as moisture content, pH, temperature, and aeration, on cellulase production by Trichoderma harzianum using a mixture of wheat straw (80%) and bran (20%) were investigated. With a moisture content of 74% and a pH of 5.8, 18 IU filter paper activity and 198 IU endoglucanase activity/g initial substrate content were obtained in 66 hours. The extension from static column cultivation to stirred tank reactor of 65 l capacity gave similar yields of cellulase.

Separated type nuclear superheating reactor

International Nuclear Information System (INIS)

Hida, Kazuki.

1993-01-01

In a separated type nuclear superheating reactor, fuel assemblies used in a reactor core comprise fuel rods made of nuclear fuel materials and moderator rods made of solid moderating materials such as hydrogenated zirconium. Since the moderating rods are fixed or made detachable, high energy neutrons generated from the fuel rods are moderated by the moderating rods to promote fission reaction of the fuel rods. Saturated steams supplied from the BWR type reactor by the fission energy are converted to high temperature superheated steams while passing through a steam channel disposed between the fuel rods and the moderating rods and supplied to a turbine. Since water is not used but solid moderating materials sealed in a cladding tube are used as moderation materials, isolation between superheated steams and water as moderators is not necessary. Further, since leakage of heat is reduced to improve a heat efficiency, the structure of the reactor core is simplified and fuel exchange is facilitated. (N.H.)

Radiological monitoring related to the operation of PUSPATI's Triga Reactor

International Nuclear Information System (INIS)

Fatimah Mohamad Amin; Mohamad Yusof Mohamad Ali; Lau How Mooi; Idris Besar.

1983-01-01

Reactor operation is one of the main activities carried out at the Tun Ismail Atomic Research Centre (PUSPATI) which requires radiological monitoring. This paper describes the programme for radiological monitoring which is related to the operation of the 1 MW Triga MK II research reactor which was commissioned in July, 1982. This programme includes monitoring of the radiation and contamination levels of the reactor and its associated facilities and environmental monitoring of PUSPATI's site and its environs. The data presented in this paper covers the period between 1982 to 1983 which includes both the pre-operational and operational phases of the monitoring programme. (author)

Improvement in or relating to methods and apparatus for refuelling nuclear reactors

International Nuclear Information System (INIS)

Shumyakin, E.P.; Sabir-de-Ribas, K.I.; Druzhinsky, I.A.; Kondratiev, P.V.; Andreichikov, B.I.; Slepov, L.M.; Borisjuk, E.V.; Smirnov, A.M.

1977-01-01

This invention relates to improvements in the methods and in the apparatus used for refuelling liquid metal cooled fast reactors and in particular to systems for cooling the fuel assemblies as they are removed from the reactor. (UK)

Immobilization of metal-humic acid complexes in anaerobic granular sludge for their application as solid-phase redox mediators in the biotransformation of iopromide in UASB reactors.

Science.gov (United States)

Cruz-Zavala, Aracely S; Pat-Espadas, Aurora M; Rangel-Mendez, J Rene; Chazaro-Ruiz, Luis F; Ascacio-Valdes, Juan A; Aguilar, Cristobal N; Cervantes, Francisco J

2016-05-01

Metal-humic acid complexes were synthesized and immobilized by a granulation process in anaerobic sludge for their application as solid-phase redox mediators (RM) in the biotransformation of iopromide. Characterization of Ca- and Fe-humic acid complexes revealed electron accepting capacities of 0.472 and 0.556milli-equivalentsg(-1), respectively. Once immobilized, metal-humic acid complexes significantly increased the biotransformation of iopromide in upflow anaerobic sludge blanket (UASB) reactors. Control UASB reactor (without humic material) achieved 31.6% of iopromide removal, while 80% was removed in UASB reactors supplied with each metal-humic acid complex. Further analyses indicated multiple transformation reactions taking place in iopromide including deiodination, N-dealkylation, decarboxylation and deacetylation. This is the first successful application of immobilized RM, which does not require a supporting material to maintain the solid-phase RM in long term operation of bioreactors. The proposed redox catalyst could be suitable for enhancing the redox conversion of different recalcitrant pollutants present in industrial effluents. Copyright © 2016 Elsevier Ltd. All rights reserved.

Flow-based method for epinephrine determination using a solid reactor based on molecularly imprinted poly(FePP-MAA-EGDMA)

International Nuclear Information System (INIS)

Sartori, Lucas Rossi; Santos, Wilney de Jesus Rodrigues; Kubota, Lauro Tatsuo; Segatelli, Mariana Gava; Tarley, Cesar Ricardo Teixeira

2011-01-01

A solid phase reactor based on molecularly imprinted poly(iron (III) protoporphyrin-methacrylic acid-ethylene glycol dimethacrylate) (MIP-MAA) has been synthesized by bulk method and applied as an selective material for the epinephrine determination in the presence of hydrogen peroxide. In order to prove the selective behaviour of MIP, two blank polymers named non-imprinted polymer (NIP1), non-imprinted polymer in the absence of hemin (NIP2) as well as a poly(iron (III) protoporphyrin-4-vynilpyridine-ethylene glycol dimethacrylate) (MIP-4VPy) were synthesized. The epinephrine-selective MIP-MAA reactor was used in a flow injection system, in which an epinephrine solution (120 μL) at pH 8.0 percolates in the presence of hydrogen peroxide (300 μmol L -1 ) through MIP-MAA. The oxidation of epinephrine by hydrogen peroxide is increased by using MIP-MAA, being the product formed monitored by amperometry at 0.0 V vs. Ag/AgCl. The MIP-MAA showed better selective behaviour than NIP1, NIP2 and MIP-4VPy, demonstrating the effectiveness of molecular imprinting effect. Highly improved response was observed for epinephrine in detriment of similar substances (phenol, ascorbic acid, methyl-L-DOPA, p-aminophenol, catechol, L-DOPA and guaiacol). The method provided a calibration curve ranging from 10 to 500 μmol L -1 and a limit of detection of 5.2 μmol L -1 . Kinetic data indicated a value of maximum rate V max (0.993 μA) and apparent Michaelis-Menten constant of K m app (725.6 μmol L -1 ). The feasibility of biomimetic solid reactor was attested by its successful application for epinephrine determination in pharmaceutical formulation.

Hydrodynamic study of an internal airlift reactor for microalgae culture.

Science.gov (United States)

Rengel, Ana; Zoughaib, Assaad; Dron, Dominique; Clodic, Denis

2012-01-01

Internal airlift reactors are closed systems considered today for microalgae cultivation. Several works have studied their hydrodynamics but based on important solid concentrations, not with biomass concentrations usually found in microalgae cultures. In this study, an internal airlift reactor has been built and tested in order to clarify the hydrodynamics of this system, based on microalgae typical concentrations. A model is proposed taking into account the variation of air bubble velocity according to volumetric air flow rate injected into the system. A relationship between riser and downcomer gas holdups is established, which varied slightly with solids concentrations. The repartition of solids along the reactor resulted to be homogenous for the range of concentrations and volumetric air flow rate studied here. Liquid velocities increase with volumetric air flow rate, and they vary slightly when solids are added to the system. Finally, liquid circulation time found in each section of the reactor is in concordance with those employed in microalgae culture.

Development of a coupled reactor with a catalytic combustor and steam reformer for a 5 kW solid oxide fuel cell system

International Nuclear Information System (INIS)

Kang, Sanggyu; Lee, Kanghun; Yu, Sangseok; Lee, Sang Min; Ahn, Kook-Young

2014-01-01

Highlights: • Proposes the scale-up strategy to develop a large-scale coupled reactor. • Investigation of performance of steam reformer coupled with catalytic combustor. • Experimental parameters are inlet temp., air excess ratio, SCR, fuel utilization. • Evaluation of the heat transfer distribution along the gas flow direction. • The mean value of methane conversion rate is approximately 93.4%. - Abstract: The methane (CH 4 ) conversion rate of a steam reformer can be increased by thermal integration with a catalytic combustor, called a coupled reactor. In the present study, a 5 kW coupled reactor has been developed based on a 1 kW coupled reactor in previous work. The geometric parameters of the space velocity, diameter and length of the coupled reactor selected from the 1 kW coupled reactor are tuned and applied to the design of the 5 kW coupled reactor. To confirm the scale-up strategy, the performance of 5 kW coupled reactor is experimentally investigated with variations of operating parameters such as the fuel utilization in the solid oxide fuel cell (SOFC) stack, the inlet temperature of the catalytic combustor, the excess air ratio of the catalytic combustor, and the steam to carbon ratio (SCR) in the steam reformer. The temperature distributions of coupled reactors are measured along the gas flow direction. The gas composition at the steam reformer outlet is measured to find the CH 4 conversion rate of the coupled reactor. The maximum value of the CH 4 conversion rate is approximately 93.4%, which means the proposed scale-up strategy can be utilized to develop a large-scale coupled reactor

Radiation protection at the RA Reactor in 1993, RA research reactor, Part

International Nuclear Information System (INIS)

Ninkovic, M.; Pavlovic, R.; Mandic, M.; Sipka, V.; Grsic, Z.

1993-01-01

Radiation protection tasks which enable safe operation of the RA reactor, and are defined according the the legal regulations and IAEA safety recommendations are sorted into four categories in this report: (1) Control of the working environment, dosimetry and radiation protection at the RA reactor; (2) decontamination, collecting and treatment of fluid effluents and solid wastes; (3) Radioactivity control in the vicinity of the reactor and (4)meteorology measurements; (3). Each of the category is described as a separate annex of this report [sr

RA Research nuclear reactor, Part II: radiation protection at the RA reactor in 1987

International Nuclear Information System (INIS)

Ninkovic, M.; Ajdacic, N.; Zaric, M.; Vukovic, Z.

1987-01-01

Radiation protection tasks which enable safe operation of the RA reactor, and are defined according the the legal regulations and IAEA safety recommendations are sorted into four categories in this report: (1) Control of the working environment, dosimetry at the RA reactor and radiation protection; (2) Radioactivity control in the vicinity of the reactor and meteorology measurements; (3) Decontamination and relevant actions, collecting and treatment of fluid effluents; and and solid radioactive wastes [sr

Radiation protection at the RA Reactor in 1988, Part -2, RA reactor annual report

International Nuclear Information System (INIS)

Ninkovic, M.; Ajdacic, N.; Zaric, M.; Vukovic, Z.

1988-01-01

Radiation protection tasks which enable safe operation of the RA reactor, and are defined according the the legal regulations and IAEA safety recommendations are sorted into four categories in this report: (1) Control of the working environment, dosimetry at the RA reactor and radiation protection; (2) Radioactivity control in the vicinity of the reactor and meteorology measurements; (3) Decontamination and relevant actions, collecting and treatment of fluid effluents; and and solid radioactive wastes [sr

Biogasification of solid wastes by two-phase anaerobic fermentation

International Nuclear Information System (INIS)

Ghosh, S.; Vieitez, E.R.; Liu, T.; Kato, Y.

1997-01-01

Municipal, industrial and agricultural solid wastes, and biomass deposits, cause large-scale pollution of land and water. Gaseous products of waste decomposition pollute the air and contribute to global warming. This paper describes the development of a two-phase fermentation system that alleviates methanogenic inhibition encountered with high-solids feed, accelerates methane fermentation of the solid bed, and captures methane (renewable energy) for captive use to reduce global warming. The innovative system consisted of a solid bed reactor packed with simulated solid waste at a density of 160 kg/m 3 and operated with recirculation of the percolated culture (bioleachate) through the bed. A rapid onset of solids hydrolysis, acidification, denitrification and hydrogen gas formation was observed under these operating conditions. However, these fermentative reactions stopped at a total fatty acids concentration of 13,000 mg/l (as acetic) at pH 5, with a reactor head-gas composition of 75 percent carbon dioxide, 20 percent nitrogen, 2 percent hydrogen and 3 percent methane. Fermentation inhibition was alleviated by moving the bioleachate to a separate methane-phase fermenter, and recycling methanogenic effluents at pH 7 to the solid bed. Coupled operation of the two reactors promoted methanogenic conversion of the high-solids feed. (author)

Evolution of the liquid metal reactor: The Integral Fast Reactor (IFR) concept

International Nuclear Information System (INIS)

Till, C.E.; Chang, Y.I.

1989-01-01

The Integral Fast Reactor (IFR) concept has been under development at Argonne National Laboratory since 1984. A key feature of the IFR concept is the metallic fuel. Metallic fuel was the original choice in early liquid metal reactor development. Solid technical accomplishments have been accumulating year after year in all aspects of the IFR development program. But as we make technical progress, the ultimate potential offered by the IFR concept as a next generation advanced reactor becomes clearer and clearer. The IFR concept can meet all three fundamental requirements needed in a next generation reactor. This document discusses these requirements: breeding, safety, and waste management. 5 refs., 4 figs

Report on safety related occurrences and reactor trips July 1, 1979 - December 31, 1979

International Nuclear Information System (INIS)

Olsson, S.; Andermo, L.

1980-01-01

This is a report on all reported safety related occurrences and reactor trips in Swedish nuclear power plants in operation during July 1 to December 31, 1979 inclusive. The facilities involved are Barsebaeck 1 and 2, Oskarshamn 1 and 2 and Ringhals 1 and 2. During this period of 6 months 76 safety related occurrences and 27 reactor trips have been reported to the Nuclear Power Inspectorate. It is to the greatest extent conventional components such as valves and pumps which bring about the safety related occurrences or occurrences leading to outages or power reductions. However, the component errors discovered in the safety related systems have not affected the function of their redundant system and other diverse systems have not been involved. Therefore the reactor safety has been satisfactory. The total number of reactor trips are normal. The average value for these 6 months is 4.5 trips/unit. Approximetely one half of the reactor trips happened at zero or very low power operation. The fact that even small deviations from prescribed operation result in an automatic and safe shut down of the reactor, does not always imply a conflict with operational availability. The greatest outages are caused by occurrences without safety significance. (author)

Special needs of the developing countries as related to research reactors

International Nuclear Information System (INIS)

1979-02-01

After a short review of the particular operating conditions for research reactors in developing countries, these reactors are presented in a tabular survey. The appendix deals mostly with the possible ways to reduce the degree of enrichment of the uranium fuel. This attempted reduction is closely related with the attempts to improve the non-proliferation policy

Operational strategies for thermophilic anaerobic digestion of organic fraction of municipal solid waste in continuously stirred tank reactors

DEFF Research Database (Denmark)

Angelidaki, Irini; Cui, J.; Chen, X.

2006-01-01

Three operational strategies to reduce inhibition due to ammonia during thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste (SS-OFMSW) rich in proteins were investigated. Feed was prepared by diluting SS-OFMSW (ratio of 1:4) with tap water or reactor process...... ammonium bicarbonate additions. Dilution of SS-OFMSW with fresh water showed a stable performance with volatile fatty acids of solids (VS). Use of recirculated process water after stripping ammonia showed even better performance with a methane yield...... of 0.43 m(3) kg(-1)VS. Recirculation of process water alone on the other hand, resulted in process inhibition at both TAN levels of 3.5 and 5.5 g-N l(-1). However, after a short period, the process recovered and adapted to the tested TAN levels. Thus, use of recirculated process water after stripping...

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

NARCIS (Netherlands)

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

2009-01-01

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

Inquiry relating to modifications of reactor installation in Genkai No. 1 and 2 nuclear power plants of Kyushu Electric Power Company, Inc

International Nuclear Information System (INIS)

1979-01-01

Application was made to the Minister of International Trade and Industry for the license relating to the modifications of reactor installation in the Genkai No. 1 and 2 nuclear power plants, Kyushu Electric Power Company, Inc., on February 27, 1979, from the president of the company. After the safety evaluation was finished by the Ministry of International Trade and Industry, inquiry was conducted to the head of the Atomic Energy Safety Commission (AESC) on June 15, 1979 from the Minister of International Trade and Industry. The investigation and discussion were commenced by the AESC on June 19, 1979. The modifications of the reactor installation are the increase of new fuel storage capacity from about 1/3 to about 2/3 of in-core fuel for each plant, the new establishment of a miscellaneous solid waste incinerator which is common to both plants, and the enlargement of a solid waste storage which is also common to both plants. The contents of the safety examination for each item written above are presented. The prevention of criticality is carefully practiced for the new fuel storage by putting fuel assemblies in stainless steel can type racks and locating the fuel assemblies at the proper distance. The miscellaneous solid waste incinerator building is designed as the B class aseismatic structure and also as the controlled area with adequate shielding and ventilating facilities. The decontamination factor of the incinerator facility is more than 10 5 , and the necessary monitoring system is provided in the building. Concerning the solid waste storage, the additional storage area is about 1600 m 2 , and the storage capacity is about ten years quantity. This building is designed as the B class aseismatic structure. (Nakai, Y.)

Effect of increasing total solids contents on anaerobic digestion of food waste under mesophilic conditions: performance and microbial characteristics analysis.

Directory of Open Access Journals (Sweden)

Jing Yi

Full Text Available The total solids content of feedstocks affects the performances of anaerobic digestion and the change of total solids content will lead the change of microbial morphology in systems. In order to increase the efficiency of anaerobic digestion, it is necessary to understand the role of the total solids content on the behavior of the microbial communities involved in anaerobic digestion of organic matter from wet to dry technology. The performances of mesophilic anaerobic digestion of food waste with different total solids contents from 5% to 20% were compared and the microbial communities in reactors were investigated using 454 pyrosequencing technology. Three stable anaerobic digestion processes were achieved for food waste biodegradation and methane generation. Better performances mainly including volatile solids reduction and methane yield were obtained in the reactors with higher total solids content. Pyrosequencing results revealed significant shifts in bacterial community with increasing total solids contents. The proportion of phylum Chloroflexi decreased obviously with increasing total solids contents while other functional bacteria showed increasing trend. Methanosarcina absolutely dominated in archaeal communities in three reactors and the relative abundance of this group showed increasing trend with increasing total solids contents. These results revealed the effects of the total solids content on the performance parameters and the behavior of the microbial communities involved in the anaerobic digestion of food waste from wet to dry technologies.

Effect of Increasing Total Solids Contents on Anaerobic Digestion of Food Waste under Mesophilic Conditions: Performance and Microbial Characteristics Analysis

Science.gov (United States)

Jin, Jingwei; Dai, Xiaohu

2014-01-01

The total solids content of feedstocks affects the performances of anaerobic digestion and the change of total solids content will lead the change of microbial morphology in systems. In order to increase the efficiency of anaerobic digestion, it is necessary to understand the role of the total solids content on the behavior of the microbial communities involved in anaerobic digestion of organic matter from wet to dry technology. The performances of mesophilic anaerobic digestion of food waste with different total solids contents from 5% to 20% were compared and the microbial communities in reactors were investigated using 454 pyrosequencing technology. Three stable anaerobic digestion processes were achieved for food waste biodegradation and methane generation. Better performances mainly including volatile solids reduction and methane yield were obtained in the reactors with higher total solids content. Pyrosequencing results revealed significant shifts in bacterial community with increasing total solids contents. The proportion of phylum Chloroflexi decreased obviously with increasing total solids contents while other functional bacteria showed increasing trend. Methanosarcina absolutely dominated in archaeal communities in three reactors and the relative abundance of this group showed increasing trend with increasing total solids contents. These results revealed the effects of the total solids content on the performance parameters and the behavior of the microbial communities involved in the anaerobic digestion of food waste from wet to dry technologies. PMID:25051352

Effect of increasing total solids contents on anaerobic digestion of food waste under mesophilic conditions: performance and microbial characteristics analysis.

Science.gov (United States)

Yi, Jing; Dong, Bin; Jin, Jingwei; Dai, Xiaohu

2014-01-01

The total solids content of feedstocks affects the performances of anaerobic digestion and the change of total solids content will lead the change of microbial morphology in systems. In order to increase the efficiency of anaerobic digestion, it is necessary to understand the role of the total solids content on the behavior of the microbial communities involved in anaerobic digestion of organic matter from wet to dry technology. The performances of mesophilic anaerobic digestion of food waste with different total solids contents from 5% to 20% were compared and the microbial communities in reactors were investigated using 454 pyrosequencing technology. Three stable anaerobic digestion processes were achieved for food waste biodegradation and methane generation. Better performances mainly including volatile solids reduction and methane yield were obtained in the reactors with higher total solids content. Pyrosequencing results revealed significant shifts in bacterial community with increasing total solids contents. The proportion of phylum Chloroflexi decreased obviously with increasing total solids contents while other functional bacteria showed increasing trend. Methanosarcina absolutely dominated in archaeal communities in three reactors and the relative abundance of this group showed increasing trend with increasing total solids contents. These results revealed the effects of the total solids content on the performance parameters and the behavior of the microbial communities involved in the anaerobic digestion of food waste from wet to dry technologies.

Improvements in or relating to nuclear reactors

International Nuclear Information System (INIS)

Timofeev, A.V.; Batjukov, V.I.; Fadeev, A.I.; Shapkin, A.F.; Shikhiyan, T.G.; Ordynsky, G.V.; Drachev, V.P.; Pogodin, E.N.

1980-01-01

A refuelling installation for nuclear reactor complexes is described for recharging the reactor vessels of such complexes with new fuel assemblies and for removing spent fuel assemblies from the reactor vessel. (U.K.)

Experimental Methods Related to Coupled Fast-Thermal Systems at the RB Reactor

International Nuclear Information System (INIS)

Pesic, M.

2002-01-01

In addition to the review of RB reactor characteristics this presentation is focused on the coupled fast-thermal systems achieved at the reactor. The following experimental methods are presented: neutron spectra measurements; steady state experiments and kinetic measurements ( β eff ) related to the coupled fast-thermal cores

Operation of Packed-Bed Reactors Studied in Microgravity

Science.gov (United States)

Motil, Brian J.; Balakotaiah, Vemuri

2004-01-01

The operation of a packed bed reactor (PBR) involves gas and liquid flowing simultaneously through a fixed-bed of solid particles. Depending on the application, the particles can be various shapes and sizes but are generally designed to force the two fluid phases through a tortuous route of narrow channels connecting the interstitial space. The PBR is the most common type of reactor in industry because it provides for intimate contact and high rates of transport between the phases needed to sustain chemical or biological reactions. The packing may also serve as either a catalyst or as a support for growing biological material. Furthermore, this type of reactor is relatively compact and requires minimal power to operate. This makes it an excellent candidate for unit operations in support of long-duration human space activities.

Flow-based method for epinephrine determination using a solid reactor based on molecularly imprinted poly(FePP-MAA-EGDMA)

Energy Technology Data Exchange (ETDEWEB)

Sartori, Lucas Rossi [Programa de Pos-Graduacao em Ciencias Farmaceuticas, Universidade Federal de Alfenas (Unifal-MG), Rua Gabriel Monteiro da Silva, 714, 37130-000, Alfenas/MG (Brazil); Santos, Wilney de Jesus Rodrigues [Departamento de Quimica Analitica, Instituto de Quimica, Universidade Estadual de Campinas (Unicamp), Cidade Universitaria Zeferino Vaz s/n,13083-970, Campinas/SP (Brazil); Kubota, Lauro Tatsuo [Departamento de Quimica Analitica, Instituto de Quimica, Universidade Estadual de Campinas (Unicamp), Cidade Universitaria Zeferino Vaz s/n,13083-970, Campinas/SP (Brazil); Instituto Nacional de Ciencia e Tecnologia (INCT) de Bioanalitica, Universidade Estadual de Campinas (Unicamp), Instituto de Quimica, Departamento de Quimica Analitica, Cidade Universitaria Zeferino Vaz s/n, 13083-970, Campinas/SP (Brazil); Segatelli, Mariana Gava [Departamento de Quimica, Universidade Estadual de Londrina (UEL), Rod. Celso Garcia PR 445 Km 380, 86051-990, Londrina/PR (Brazil); Tarley, Cesar Ricardo Teixeira, E-mail: tarley@uel.br [Programa de Pos-Graduacao em Ciencias Farmaceuticas, Universidade Federal de Alfenas (Unifal-MG), Rua Gabriel Monteiro da Silva, 714, 37130-000, Alfenas/MG (Brazil); Instituto Nacional de Ciencia e Tecnologia (INCT) de Bioanalitica, Universidade Estadual de Campinas (Unicamp), Instituto de Quimica, Departamento de Quimica Analitica, Cidade Universitaria Zeferino Vaz s/n, 13083-970, Campinas/SP (Brazil)

2011-03-12

A solid phase reactor based on molecularly imprinted poly(iron (III) protoporphyrin-methacrylic acid-ethylene glycol dimethacrylate) (MIP-MAA) has been synthesized by bulk method and applied as an selective material for the epinephrine determination in the presence of hydrogen peroxide. In order to prove the selective behaviour of MIP, two blank polymers named non-imprinted polymer (NIP1), non-imprinted polymer in the absence of hemin (NIP2) as well as a poly(iron (III) protoporphyrin-4-vynilpyridine-ethylene glycol dimethacrylate) (MIP-4VPy) were synthesized. The epinephrine-selective MIP-MAA reactor was used in a flow injection system, in which an epinephrine solution (120 {mu}L) at pH 8.0 percolates in the presence of hydrogen peroxide (300 {mu}mol L{sup -1}) through MIP-MAA. The oxidation of epinephrine by hydrogen peroxide is increased by using MIP-MAA, being the product formed monitored by amperometry at 0.0 V vs. Ag/AgCl. The MIP-MAA showed better selective behaviour than NIP1, NIP2 and MIP-4VPy, demonstrating the effectiveness of molecular imprinting effect. Highly improved response was observed for epinephrine in detriment of similar substances (phenol, ascorbic acid, methyl-L-DOPA, p-aminophenol, catechol, L-DOPA and guaiacol). The method provided a calibration curve ranging from 10 to 500 {mu}mol L{sup -1} and a limit of detection of 5.2 {mu}mol L{sup -1}. Kinetic data indicated a value of maximum rate V{sub max} (0.993 {mu}A) and apparent Michaelis-Menten constant of K{sub m}{sup app}(725.6 {mu}mol L{sup -1}). The feasibility of biomimetic solid reactor was attested by its successful application for epinephrine determination in pharmaceutical formulation.

Report on safety related occurrences and reactor trips July 1, 1976-December 31, 1976

International Nuclear Information System (INIS)

Andermo, L.

1977-04-01

This is a systematically arranged report on all reported safety related occurrences and reactor trips in Swedish nuclear power plants in operation during July 1, 1976 to December 31, 1976 inclusive. The facilities involved are Oskarshamn 1 and 2, Ringhals 1 and 2 and Barsebaeck 1. During this period of the 6 months 37 safety related occurrences and 34 reactor trips have been reported to the Nuclear Power Inspectorate. As earlier experiences have shown it is to the greatest extent the conventional components which bring about the safety related occurrences or occurrences leading to outages or power reductions. However, the component errors discovered in the safety related systems have not affected the function of their redundant systems and other diverse systems have not been involved. Therefore the reactor safety has been satisfactory. The fact that even small deviations from prescribed operation results in automatic and safe shut down of the reactor, does not always imply a conflict with operational availability. The number of reactor trips are almost as low as during the last period, which is a drastic reduction compared to earlier time periods. The greatest outages are caused by occurrences without safety significance.(author)

The use of wire mesh reactors to characterise solid fuels and provide improved understanding of larger scale thermochemical processes

Energy Technology Data Exchange (ETDEWEB)

Lu Gao; Long Wu; Nigel Paterson; Denis Dugwell; Rafael Kandiyoti [Imperial College London, London (United Kingdom). Department of Chemical Engineering

2008-07-01

Most reaction products from the pyrolysis and the early stages of gasification of solid fuels are chemically reactive. Secondary reactions between primary products and with heated fuel particles tend to affect the final product distributions. The extents and pathways of these secondary reactions are determined mostly by the heating rate and the size and shape of the reaction zone and of the sample itself. The wire-mesh reactor (WMR) configuration discussed in this paper allows products to be separated from reactants and enables the rapid quenching of products, allowing suppression of secondary reactions. This paper presents an overview of the development of wire-mesh reactors, describing several diverse applications. The first of these involves an analysis of the behaviour of injectant coal particles in blast furnace tuyeres and raceways. The data has offered explanations for helping to understand why, at high coal injection rates, problems can be encountered in the operation of blast furnaces. Another project focused on determining the extents of pyrolysis and gasification reactivities of a suite of Chinese coals under intense reaction conditions. The results showed variations in coal reactivities that were related to the C content. In another project demonstrating the versatility of the WMR configuration, the high pressure version of the reactor is being used for developing the Zero Emission Coal Alliance (ZECA) concept. The work aims to examine and explain the chemical and transport mechanisms underlying the pyrolysis, hydropyrolysis and hydrogasification stages of the process. The results obtained till date have shown the effects of the operating conditions on the extent of hydropyrolysis/gasification of a bituminous coal and two lignites. The lignites were more reactive than the coal, and the data suggests that high levels of conversion will be achievable under the anticipated ZECA process conditions. 29 refs., 15 figs., 7 tabs.

Report on safety related occurrences and reactor trips July 1, 1977 - December 31, 1977

International Nuclear Information System (INIS)

Andermo, L.; Sundman, B.

1974-04-01

This is a systematically arranged report on all reported safety related occurrences and reactor trips in Swedish nuclear power plants in operation during July 1 to December 31, 1977 inclusive. The facilities involved are Barsebaeck 1 and 2, Oskarshamn 1 and 2 and Ringhals 1 and 2. During this period of 6 months 48 safety related occurrences and 49 reactor trips have been reported to the Nuclear Power Inspectorate. Included is also one incident June 21 in Barsebaeck 2 which was not included in the last compilation of occurrences. As earlier experiences have shown it is to the greatest extent the conventional components which bring about the safety related occurrences or occurrences leading to outages or power reductions. However, the component errors discovered in the safety related systems have not affected the function of their redundant systems and other diverse systems have not been involved. Therefore the reactor safety has been satisfactory. The total number of reactor trips have increased nearly 30% since the last period. Those occurred during power operation however, were less. More than 50% of the reactor trips happened in the shutdown condition. The fact that even small deviations from prescribed operation result in automatic and safe shut down of the reactor, does not always imply a conflict with operational availability. The greatest outages are caused by occurrences withou02068NRM 0000169 450

Breeding blankets for thermonuclear reactors

International Nuclear Information System (INIS)

Rocaboy, Alain.

1982-06-01

Materials with structures suitable for this purpose are studied. A bibliographic review of the main solid and liquid lithiated compounds is then presented. Erosion, dimensioning and maintenance problems associated with the limiter and the first wall of the reactor are studied from the point of view of the constraints they impose on the design of the blankets. Detailed studies of the main solid and liquid blanket concepts enable the best technological compromises to be determined for the indispensable functions of the blanket to be assured under acceptable conditions. Our analysis leads to four classes of solution, which cannot at this stage be considered as final recommendations, but which indicate what sort of solutions it is worthwhile exploring and comparing in order to be in a position to suggest a realistic blanket at the time when plasma control is sufficiently good for power reactors to be envisaged. Some considerations on the general architecture of the reactor are indicated. Energy storage with pulsed reactors is discussed in the appendix, and a first approach made to minimizing the total tritium recovery [fr

State of exposure control for workers engaging in radiation works and state of radioactive waste management in nuclear reactor facilities for test and research and nuclear reactor facilities at research and development stage, fiscal year 1995

International Nuclear Information System (INIS)

1996-01-01

This is the summary of the reports submitted in fiscal year 1995 by the installers of the nuclear reactor facilities for test and research or at research and development stage, conforming to the related law. The individual dose equivalent of the workers engaging in radiation works in fiscal year 1995 was sufficiently lower than the prescribed limit in all reactor facilities. As for the released quantities of gaseous and liquid wastes, the radioactive substances in the air and water outside the monitor zones never exceeded the prescribed concentration limit in all reactor facilities. In the reactor facilities, for which the target values of release control have been determined, the values were less than the targets in all cases. The increase of stored radioactive solid waste decreased as the dismantling works of the reactor auxiliary system of the nuclear powered ship 'Mutsu' were finished in fiscal year 1994. As the amount of stored radioactive solid waste approaches the installed capacity, the preservation capacity of the existing waste preservation building was increased. (K.I.)

Prokaryotic diversity and dynamics in a full-scale municipal solid waste anaerobic reactor from start-up to steady-state conditions.

Science.gov (United States)

Cardinali-Rezende, Juliana; Colturato, Luís F D B; Colturato, Thiago D B; Chartone-Souza, Edmar; Nascimento, Andréa M A; Sanz, José L

2012-09-01

The prokaryotic diversity of an anaerobic reactor for the treatment of municipal solid waste was investigated over the course of 2 years with the use of 16S rDNA-targeted molecular approaches. The fermentative Bacteroidetes and Firmicutes predominated, and Proteobacteria, Actinobacteria, Tenericutes and the candidate division WWE1 were also identified. Methane production was dominated by the hydrogenotrophic Methanomicrobiales (Methanoculleus sp.) and their syntrophic association with acetate-utilizing and propionate-oxidizing bacteria. qPCR demonstrated the predominance of the hydrogenotrophic over aceticlastic Methanosarcinaceae (Methanosarcina sp. and Methanimicrococcus sp.), and Methanosaetaceae (Methanosaeta sp.) were measured in low numbers in the reactor. According to the FISH and CARD-FISH analyses, Bacteria and Archaea accounted for 85% and 15% of the cells, respectively. Different cell counts for these domains were obtained by qPCR versus FISH analyses. The use of several molecular tools increases our knowledge of the prokaryotic community dynamics from start-up to steady-state conditions in a full-scale MSW reactor. Copyright © 2012 Elsevier Ltd. All rights reserved.

Advantages of liquid fluoride thorium reactor in comparison with light water reactor

Energy Technology Data Exchange (ETDEWEB)

Bahri, Che Nor Aniza Che Zainul, E-mail: anizazainul@gmail.com; Majid, Amran Ab.; Al-Areqi, Wadeeah M. [Nuclear Science Program, School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia)

2015-04-29

Liquid Fluoride Thorium Reactor (LFTR) is an innovative design for the thermal breeder reactor that has important potential benefits over the traditional reactor design. LFTR is fluoride based liquid fuel, that use the thorium dissolved in salt mixture of lithium fluoride and beryllium fluoride. Therefore, LFTR technology is fundamentally different from the solid fuel technology currently in use. Although the traditional nuclear reactor technology has been proven, it has perceptual problems with safety and nuclear waste products. The aim of this paper is to discuss the potential advantages of LFTR in three aspects such as safety, fuel efficiency and nuclear waste as an alternative energy generator in the future. Comparisons between LFTR and Light Water Reactor (LWR), on general principles of fuel cycle, resource availability, radiotoxicity and nuclear weapon proliferation shall be elaborated.

Particulate COD balance of particulate cod in eletrocuagulation/flotation reactor treating tannery effluent

Directory of Open Access Journals (Sweden)

Rodrigo Babora Borri

2012-04-01

Full Text Available Mass balance or particulate organic matter was studied in terms of COD, by means of electrocoagulation/flotation (ECF reactor treating tannery effluent. Reactor was operated in fill and draw (batch mode. Operating in hydraulic residence time of 65 minutes, ECF reactor reached 55 % COD removal. Although volatile solids were also removed from liquid phase (removal of 40%, fixed solids concentration, and hence total solids concentration, showed to be higher in withdrawn effluent than in ECF’s influent. This was assigned to NaCl added in order to enhance conductivity in wastewater.

Technical Meeting on Fast Reactors and Related Fuel Cycle Facilities with Improved Economic Characteristics. Presentations

International Nuclear Information System (INIS)

2013-01-01

The objectives of the meeting were: • To identify the main issues and technical features that affect capital and energy production costs of fast reactors and related fuel cycle facilities; • To present fast reactor concepts and designs with enhanced economic characteristics, as well as innovative technical solutions (components, subsystems, etc.) that have the potential to reduce the capital costs of fast reactors and related fuel cycle facilities; • To present energy models and advanced tools for the cost assessment of innovative fast reactors and associated nuclear fuel cycles; • To discuss the results of studies and ongoing R&D activities that address cost reduction and the future economic competitiveness of fast reactors; • To identify research and technology development needs in the field, also in view of new IAEA initiatives to help and support Member States in improving the economic competitiveness of fast reactors and associated nuclear fuel cycles

Light-water reactors. Safety problems and related studies in France

International Nuclear Information System (INIS)

Lelievre, J.

1975-01-01

The program of theoretical and experimental studies developed by the CEA on the safety of PWR reactors is presented: studies relative to the consequences of a LOCA following a rupture of the primary system, studies relative to fuel element behavior, studies on steels, reliability studies and studies of non-destructive testing methods [fr

Integral reactor system and method for fuel cells

Science.gov (United States)

Fernandes, Neil Edward; Brown, Michael S; Cheekatamarla, Praveen; Deng, Thomas; Dimitrakopoulos, James; Litka, Anthony F

2013-11-19

A reactor system is integrated internally within an anode-side cavity of a fuel cell. The reactor system is configured to convert hydrocarbons to smaller species while mitigating the lower production of solid carbon. The reactor system may incorporate one or more of a pre-reforming section, an anode exhaust gas recirculation device, and a reforming section.

Fusion reactor materials

Energy Technology Data Exchange (ETDEWEB)

none,

1989-01-01

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

Fusion reactor materials

International Nuclear Information System (INIS)

1989-01-01

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

Modelling of sludge blanket height and flow pattern in UASB reactors treating municipal wastewater

International Nuclear Information System (INIS)

Singh, K.S.; Viraraghavan, T.

2002-01-01

Two upflow anaerobic sludge blanket (UASB) reactors were started-up and operated for approximately 900 days to examine the feasibility of treating municipal wastewater under low temperature conditions. A modified solid distribution model was formulated by incorporating the variation of biogas production rate with a change in temperature. This model was used to optimize the sludge blanket height of UASB reactors for an effective operation of gas-liquid-solid (GLS) separation device. This model was found to simulate well the solid distribution as confirmed experimental observation of solid profile along the height of the reactor. Mathematical analysis of tracer curves indicated the presence of a mixed type of flow pattern in the sludge-bed zone of the reactor. It was found that the dead-zone and by-pass flow fraction were impacted by the change in operating temperatures. (author)

Digestion of thermally hydrolyzed sewage sludge by anaerobic sequencing batch reactor

International Nuclear Information System (INIS)

Wang Zhijun; Wang Wei; Zhang Xihui; Zhang Guangming

2009-01-01

Laboratory experiments were conducted to investigate the performance of an anaerobic sequencing batch reactor (ASBR) for the digestion of thermally hydrolyzed sewage sludge. Both mesophilic ASBR and continuous-flow stirred tank reactors (CSTR) were evaluated with an equivalent loading rate of 2.71 kg COD/m 3 day at 20-day hydraulic retention time (HRT) and 5.42 kg COD/m 3 day at 10-day HRT. The average total chemical oxygen demand (TCOD) removals of the ASBR at the 20-day and 10-day HRT were 67.71% and 61.66%, respectively. These were 12.38% and 27.92% higher than those obtained by CSTR. As a result, the average daily gas production of ASBR was 15% higher than that of the CSTR at 20-day HRT, and 31% higher than that of the CSTR at 10-day HRT. Solids in thermally hydrolyzed sludge accumulated within ASBR were able to reach a high steady state with solid content of 65-80 g/L. This resulted in a relatively high solid retention time (SRT) of 34-40 days in the ASBR at 10-day HRT. However, too much solid accumulation resulted in the unsteadiness of the ASBR, making regular discharge of digested sludge from the bottom of the ASBR necessary to keep the reactor stable. The evolution of the gas production, soluble chemical oxygen demand (SCOD) and volatile fatty acids (VFAs) in an operation cycle of ASBR also showed that the ASBR was steady and feasible for the treatment of thermally hydrolyzed sludge

Enhanced treatment efficiency of an anaerobic sequencing batch reactor (ASBR) for cassava stillage with high solids content.

Science.gov (United States)

Luo, Gang; Xie, Li; Zhou, Qi

2009-06-01

Cassava stillage is a high strength organic wastewater with high suspended solids (SS) content. The efficiency of cassava stillage treatment using an anaerobic sequencing batch reactor (ASBR) was significantly enhanced by discharging settled sludge to maintain a lower sludge concentration (about 30 g/L) in the reactor. Three hydraulic retention times (HRTs), namely 10 d, 7.5 d, 5 d, were evaluated at this condition. The study demonstrated that at an HRT of 5 d and an organic loading rate (OLR) of 11.3 kg COD/(m(3) d), the total chemical oxygen demand (TCOD) and soluble COD (SCOD) removal efficiency can still be maintained at above 80%. The settleability of digested cassava stillage was improved significantly, and thus only a small amount of settled sludge needed to be discharged to maintain the sludge concentration in the reactor. Furthermore, the performance of ASBR operated at low and high sludge concentration (about 79.5 g/L without sludge discharged) was evaluated at an HRT of 5 d. The TCOD removal efficiency and SS in the effluent were 61% and 21.9 g/L respectively at high sludge concentration, while the values were 85.1% and 2.4 g/L at low sludge concentration. Therefore, low sludge concentration is recommended for ASBR treating cassava stillage at an HRT 5 d due to lower TCOD and SS in the effluent, which could facilitate post-treatment.

Transient thermal characteristics of a core channel in a molten salt reactor

International Nuclear Information System (INIS)

Sakashita, H.; Ishiguro, R.; Sugiyama, K.

1987-01-01

The present paper deals with the thermal characteristics of Molten Salt Reactor (MSR). Analyses of the fundamental behavior of internal heat generating fluid and graphite contiguous to the fluid are performed. As a result, it is known that the transient thermal characteristics of MSR differ fundamentally from those of a solid-fuel reactor, and the simplified method of thermal analysis which is commonly used for solid-fuel reactors gives optimistic predictions than the actual phenomena. (author)

The experimental nuclear reactor: AQUILON

International Nuclear Information System (INIS)

Girard, Y.; Koechlin, J.C.; Moreau, J.M.

1958-01-01

'Aquilon' is an experimental reactor specially designed for the neutronic study of heterogeneous multiplying media with solid fuel and liquid moderator. Since this study is in general incompatible with energy production, the power of the reactor has been limited to a minimum so as to be able to obtain a simple and compact structure, easy access, good handling and great flexibility of operation and utilisation. (author) [fr

Source-to-incident flux relation for a tokamak fusion test reactor blanket module

International Nuclear Information System (INIS)

Imel, G.R.

1982-01-01

The source-to-incident 14-MeV flux relation for a blanket module on the Tokamak Fusion Test Reactor is derived. It is shown that assumptions can be made that allow an analytical expression to be derived, using point kernel methods. In addition, the effect of a nonuniform source distribution is derived, again by relatively simple point kernel methods. It is thought that the methodology developed is valid for a variety of blanket modules on tokamak reactors

Hydrodynamic models for slurry bubble column reactors

Energy Technology Data Exchange (ETDEWEB)

Gidaspow, D. [IIT Center, Chicago, IL (United States)

1995-12-31

The objective of this investigation is to convert a {open_quotes}learning gas-solid-liquid{close_quotes} fluidization model into a predictive design model. This model is capable of predicting local gas, liquid and solids hold-ups and the basic flow regimes: the uniform bubbling, the industrially practical churn-turbulent (bubble coalescence) and the slugging regimes. Current reactor models incorrectly assume that the gas and the particle hold-ups (volume fractions) are uniform in the reactor. They must be given in terms of empirical correlations determined under conditions that radically differ from reactor operation. In the proposed hydrodynamic approach these hold-ups are computed from separate phase momentum balances. Furthermore, the kinetic theory approach computes the high slurry viscosities from collisions of the catalyst particles. Thus particle rheology is not an input into the model.

The CANDUR Reactor - The Practical Path to RU and TH use in Nuclear Reactors

International Nuclear Information System (INIS)

Kuran, Sermet; Yang, Dezi

2012-01-01

The CANDU heavy water reactor has unrivalled flexibility for using a variety of fuels, such as Natural Uranium (NU), Low Enriched Uranium (LEU), Recycled Uranium (RU), Mixed Oxide (MOX), and Thorium (Th). Recently, this unique CANDU reactor feature attracted considerable attention due to favourable commercial, environmental and strategic needs. This paper summarizes the solid progress over the last three years and outlines CANDU Energy Incorporated's (CEI) multi-stage vision of utilizing various fuels in currently operational and new build CANDU reactors. In CEI's fuel-cycle vision, CANDU reactors will operate in conjunction with other reactor types and use advanced fuels to produce more energy and ensure the most efficient and least costly method of utilizing Light Water Reactor (LWR) used fuel. With this vision and the tandem goal of systematic adoption of Thorium based fuels, CANDU reactors will be a strong technology partner in ensuring the availability of long-term stable resources for nuclear power plants

Proceedings of first SWCR-KURRI academic seminar on research reactors and related research topics

International Nuclear Information System (INIS)

Kimura, Itsuro; Cong, Zhebao

1986-01-01

These are the proceedings of an academic seminar on research reactors and related research topics held at the Southwest Centre for Reactor Engineering Research and Design in Chengdu, Sichuan, People's Republic of China in September 24-26 in 1985. Included are the chairmen's addresses and 10 papers presented at the seminar in English. The titles of these papers are: (1) Nuclear Safety and Safeguards, (2) General Review of Thorium Research in Japanese Universities, (3) Comprehensive Utilization and Economic Analysis of the High Flux Engineering Test Reactor, (4) Present States of Applied Health Physics in Japan, (5) Neutron Radiography with Kyoto University Reactor, (6) Topics of Experimental Works with Kyoto University Reactor, (7) Integral Check of Nuclear Data for Reactor Structural Materials, (8) The Reactor Core, Physical Experiments and the Operation Safety Regulation of the Zero Energy Thermal Reactor for PWR Nuclear Power Plant, (9) HFETR Core Physical Parameters at Power, (10) Physical Consideration for Loads of Operated Ten Cycles in HFETR. (author)

OECD Nuclear Energy Agency Activities Related to Fast Reactor Development

International Nuclear Information System (INIS)

Dujardin, Thierry; Gulliford, Jim

2013-01-01

• Despite impact of Fukushima, there remains a high level of interest in continued development of advanced nuclear systems and fuel cycles: – better use of natural resources; – minimisation of waste and reduction of constraints on deep geological repositories. • Ambitious R&D programmes on-going at national level in many countries, also through international projects: – expected to lead to development of advanced reactors and fuel cycle facilities. • OECD/NEA will continue to support member countries in field of fast reactor development and related advanced fuel cycles: – forum for exchange of information; – collaborative activities

Summary of the progress of reactor physics in Japan reviewing the activities related to NEA Committee on Reactor Physics

International Nuclear Information System (INIS)

Hirota, Jitsuya

1984-09-01

The progress of fast and thermal reactor physics, fusion neutronics and shielding researches in these twenty years can be clearly recognized in the reviews of reactor physics activities in Japan which had been perpared by the Special Committee on Reactor Physics: the joint committee under Atomic Energy Society of Japan and JAERI. Many topics of those discussed at the NEACRP meetings concerned fast reactor physics. Information exchange on the topics such as adjustment of group cross sections by integral data, central worth discrepancy, sodium void effect and heterogeneous core stimulated the researches in Japan. And achievements in Japan including those in the JAERI Fast Critical Facility FCA were reported and contributed largely to the international co-operation. In addition, the contribution from Japan was also made concerning a study of fusion blanket. Among various specialists' meetings recommended by NEACRP, those on nuclear data and benchmarks for reactor shielding were often held since 1973 and helpful to the progress of shielding researches in Japan. The Third Specialists' Meeting on Reactor Noise (SMORN-III) was held in Tokyo in 1981, indicating the recent progress in safety-related applications of reactor noise analysis. The NEACRP benchmark tests were quite useful to the progress of reactor physics in Japan, which included the benchmark calculations of BWR lattice cell, key parameters and burn-up characteristics of a large LMFBR, FBR and PWR shielding, and so on. It may be noted that the benchmark test on reactor noise analysis methods was successfully conducted by Japan in connection with SMORN-III. In addition, the co-operation was positively made to the compilation of light water lattice data, and the preparation of reviews on actinide production and burn-up, and blanket physics. (J.P.N.)

Relation of radiation damage of metallic solids to electronic structure. Pt. 5

International Nuclear Information System (INIS)

Shalaev, A.M.; Adamenko, A.A.

1977-01-01

The problem of relating a damage in metal solids to the parameters of radiation fluxes and the physical nature of a target is considered. Basing upon experimental and theoretical investigations into the processes of interaction of particle fluxes with solids, the following conclusions have been reached. Threshold energy of ion displacement in the crystal lattice of a metal solid is dependent on the energy of a bombarding particle, which is due to ionization and electroexcitation stimulated by energy transfer from a fast particle to a system of collectivized electrons. The rate of metal solid damage by radiation depends on the state of the crystal lattice, in particular on its defectness. Variations of local electron density in the vicinity of a defect are related with changing thermodynamic characteristics of radiation-induced defect formation. A type of atomic bond in a solid affects the rate of radiation damage. The greatest damage occurs in materials with a covalent bond

Survey and evaluation of handling and disposing of solid low-level nuclear fuel cycle wastes

International Nuclear Information System (INIS)

Mullarkey, T.B.; Jentz, T.L.; Connelly, J.M.; Kane, J.P.

1976-10-01

The report identifies the types and quantities of low-level solid radwaste for each portion of the nuclear fuel cycle, based on operating experiences at existing sites and design information for future installations. These facts are used to evaluate reference 1000 MWe reactor plants in terms of solid radwaste generation. The effect of waste volumes on disposal methods and land usage has also been determined, based on projections of nuclear power growth through the year 2000. The relative advantages of volume reduction alternatives are included. Major conclusions are drawn concerning available land burial space, light water reactors and fuel fabrication and reprocessing facilities. Study was conducted under the direction of an industry task force and the National Environmental Studies Project, a technical program of the Atomic Industrial Forum. Data was obtained from questionnaires sent to 8 fuel fabrication facilities, 39 reactor sites and 6 commercial waste disposal sites. Additional data were gathered from interviews with architect engineering firms, site visits, contacts with regulatory agencies and published literature

Studies in solid state ionics

International Nuclear Information System (INIS)

Jakes, D.; Rosenkranz, J.

1987-01-01

Studies performed over 10 years by the high temperature chemistry group are reviewed. Attention was paid to different aspects of ionic solids from the point of view of practical as well as theoretical needs of nuclear technology. Thus ceramic fuel compound like uranates, urania-thoria system, solid electrolytes based on oxides and ionics transformations were studied under reactor irradiation. (author) 13 figs., 3 tabs., 46 refs

Dynamic behavior of a solid particle bed in a liquid pool

International Nuclear Information System (INIS)

Liu Ping; Yasunaka, Satoshi; Matsumoto, Tatsuya; Morita, Koji; Fukuda, Kenji; Yamano, Hidemasa; Tobita, Yoshiharu

2007-01-01

Dynamic behavior of solid particle beds in a liquid pool against pressure transients was investigated to model the mobility of core materials in a postulated disrupted core of a liquid metal fast reactor. A series of experiments was performed with a particle bed of different bed heights, comprising different monotype solid particles, where variable initial pressures of the originally pressurized nitrogen gas were adopted as the pressure sources. Computational simulations of the experiments were performed using SIMMER-III, a fast reactor safety analysis code. Comparisons between simulated and experimental results show that the physical model for multiphase flows used in the SIMMER-III code can reasonably represent the transient behaviors of pool multiphase flows with rich solid phases, as observed in the current experiments. This demonstrates the basic validity of the SIMMER-III code on simulating the dynamic behaviors induced by pressure transients in a low-energy disrupted core of a liquid metal fast reactor with rich solid phases

Technical Meeting on Fast Reactors and Related Fuel Cycle Facilities with Improved Economic Characteristics. Working Material

International Nuclear Information System (INIS)

2013-01-01

The objectives of the meeting were: - To identify the main issues and technical features that affect capital and energy production costs of fast reactors and related fuel cycle facilities; - To present fast reactor concepts and designs with enhanced economic characteristics, as well as innovative technical solutions (components, subsystems, etc.) that have the potential to reduce the capital costs of fast reactors and related fuel cycle facilities; - To present energy models and advanced tools for the cost assessment of innovative fast reactors and associated nuclear fuel cycles; - To discuss the results of studies and on-going R&D activities that address cost reduction and the future economic competitiveness of fast reactors; and - To identify research and technology development needs in the field, also in view of new IAEA initiatives to help and support Member States in improving the economic competitiveness of fast reactors and associated nuclear fuel cycles

Report of scientific results 1976. Section nuclear chemistry and reactor

International Nuclear Information System (INIS)

1976-01-01

The report of the section Nuclear Chemistry and Reactor presents the results of R and D in the fields of neutron scattering, radiation damage in solids, reactor chemistry, trace elements research in biomedicine, geochemistry, reactor operation, radioisotope production, and gives a survey of publications and lectures. (HK) [de

Optimization study of ultracold neutron sources at TRIGA reactors using MCNP

International Nuclear Information System (INIS)

Pokotilovskij, Yu.N.; Rogov, A.D.

1997-01-01

Monte Carlo simulation for the optimization of ultracold and very cold neutron sources for TRIGA reactors is performed. The calculations of thermal and cold neutron fluxes from the TRIGA reactor for different positions and configurations of a very cold solid methane moderator were performed with using the MCNP program. The production of neutrons in the ultracold and very cold energy range was calculated for the most promising final moderators (converters): very cold solid deuterium and heavy methane. The radiation energy deposition was calculated for the optimized solid methane-heavy methane cold neutron moderator

Development of advanced blanket materials for solid breeder blanket of fusion reactor

International Nuclear Information System (INIS)

Ishitsuka, E.

2002-01-01

Advanced solid breeding blanket design in the DEMO reactor requires the tritium breeder and neutron multiplier that can withstand the high temperature and high dose of neutron irradiation. Therefore, the development of such advanced blanket materials is indispensable. In this paper, the cooperation activities among JAERI, universities and industries in Japan on the development of these advanced materials are reported. Advanced tritium breeding material to prevent the grain growth in high temperature had to be developed because the tritium release behavior degraded by the grain growth. As one of such materials, TiO 2 -doped Li 2 TiO 3 has been studied, and TiO 2 -doped Li 2 TiO 3 pebbles was successfully fabricated. For the advanced neutron multiplier, the beryllium intermetallic compounds that have high melting point and good chemical stability have been studied. Some characterization of Be 12 Ti was studied. The pebble fabrication study for Be 12 Ti was also performed and Be 12 Ti pebbles were successfully fabricated. From these activities, the bright prospect to realize the DEMO blanket by the application of TiO 2 -doped Li 2 TiO 3 and beryllium intermetallic compounds was obtained. (author)

Thermophysical properties of fast reactor fuel

International Nuclear Information System (INIS)

Fink, J.K.

1984-01-01

This paper identifies the fuel properties for which more data are needed for fast-reactor safety analysis. In addition, a brief review is given of current research on the vapor pressure over liquid UO 2 and (U,PU)O/sub 2-x/, the solid-solid phase transition in actinide oxides, and the thermal conductivity of molten urania

Fuel cracking in relation to fuel oxidation in support of an out-reactor instrumented defected fuel experiment

Energy Technology Data Exchange (ETDEWEB)

Quastel, A.; Thiriet, C. [Atomic Energy of Canada Limited, Chalk River, ON (Canada); Lewis, B., E-mail: brent.lewis@uoit.ca [Univ. of Ontario Inst. of Tech., Oshawa, ON (Canada); Corcoran, E., E-mail: emily.corcoran@rmc.ca [Royal Military College of Canada, Kingston, ON (Canada)

2014-07-01

An experimental program funded by the CANDU Owners Group (COG) is studying an out-reactor instrumented defected fuel experiment in Stern Laboratories (Hamilton, Ontario) with guidance from Atomic Energy of Canada Limited (AECL). The objective of this test is to provide experimental data for validation of a mechanistic fuel oxidation model. In this experiment a defected fuel element with UO{sub 2} pellets will be internally heated with an electrical heater element, causing the fuel to crack. By defecting the sheath in-situ the fuel will be exposed to light water coolant near normal reactor operating conditions (pressure 10 MPa and temperature 265-310{sup o}C) causing fuel oxidation, especially near the hotter regions of the fuel in the cracks. The fuel thermal conductivity will change, resulting in a change in the temperature distribution of the fuel element. This paper provides 2D r-θ plane strain solid mechanics models to simulate fuel thermal expansion, where conditions for fuel crack propagation are investigated with the thermal J integral to predict fuel crack stress intensity factors. Finally since fuel crack geometry can affect fuel oxidation this paper shows that the solid mechanics model with pre-set radial cracks can be coupled to a 2D r-θ fuel oxidation model. (author)

Continuous Heterogeneous Photocatalysis in Serial Micro-Batch Reactors.

Science.gov (United States)

Pieber, Bartholomäus; Shalom, Menny; Antonietti, Markus; Seeberger, Peter H; Gilmore, Kerry

2018-01-29

Solid reagents, leaching catalysts, and heterogeneous photocatalysts are commonly employed in batch processes but are ill-suited for continuous-flow chemistry. Heterogeneous catalysts for thermal reactions are typically used in packed-bed reactors, which cannot be penetrated by light and thus are not suitable for photocatalytic reactions involving solids. We demonstrate that serial micro-batch reactors (SMBRs) allow for the continuous utilization of solid materials together with liquids and gases in flow. This technology was utilized to develop selective and efficient fluorination reactions using a modified graphitic carbon nitride heterogeneous catalyst instead of costly homogeneous metal polypyridyl complexes. The merger of this inexpensive, recyclable catalyst and the SMBR approach enables sustainable and scalable photocatalysis. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The reactor core configuration and important systems related to physics tests of Daya Bay NPP

International Nuclear Information System (INIS)

Tao Shaoping

1995-06-01

A brief introduction to reactor core configuration and important systems related to physics tests of Daya Bay NPP is given. These systems involve the reactor core system (COR), the full length rod control system (RGL), the in-core instrumentation system (RIC), the out-of-core nuclear instrumentation system (RPN), and the LOCA surveillance system (LSS), the centralized data processing system (KIT) and the test data acquisition system (KDO). In addition, that the adjustment and evaluation of boron concentration related to other systems, for example the reactor coolant system (RCP), the chemical and volume control system (RCV), the reactor boron and water makeup system (REA), the nuclear sampling system (REN) and the reactor control system (RRC), etc. is also described. Analysis of these systems helps not only to familiarize their functions and acquires a deepen understanding for the principle procedure, points for attention and technical key of the core physics tests, but also to further analyze the test results. (3 refs., 11 figs., 1 tab.)

10 CFR 72.108 - Spent fuel, high-level radioactive waste, or reactor-related greater than Class C waste...

Science.gov (United States)

2010-01-01

... 10 Energy 2 2010-01-01 2010-01-01 false Spent fuel, high-level radioactive waste, or reactor... RADIOACTIVE WASTE, AND REACTOR-RELATED GREATER THAN CLASS C WASTE Siting Evaluation Factors § 72.108 Spent fuel, high-level radioactive waste, or reactor-related greater than Class C waste transportation. The...

Nuclear and thermal analyses of supercritical-water-cooled solid breeder blanket for fusion DEMO reactor

Energy Technology Data Exchange (ETDEWEB)

Yanagi, Yoshihiko; Sato, Satoshi; Enoeda, Mikio; Hatano, Toshihisa; Kikuchi, Shigeto; Kuroda, Toshimasa; Kosaku, Yasuo; Ohara, Yoshihiro [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

2001-11-01

Within a design study of a fusion DEMO reactor aiming at demonstrating technologies of fusion power plant, supercritical water is applied as a coolant of solid breeder blanket to attain high thermal efficiency. The blanket has multi-layer composed of solid breeder pebbles (Li{sub 2}O) and neutron multiplier pebbles (Be) which are radially separated by cooling panels. The first wall and the breeding region are cooled by supercritical water below and above the pseudo-critical temperature, respectively. Temperature distribution and tritium breeding ratio (TBR) have been estimated by one-dimensional nuclear and thermal calculations. The local TBR as high as 1.47 has been obtained after optimization of temperature distribution in the breeder region under the following conditions: neutron wall loading of 5 MW/m{sup 2}, {sup 6}Li enrichment of 30% and coolant temperature at inlet of breeder region of 380degC. In the case of the higher coolant temperature 430degC of the breeder region the local TBR was reduced to be 1.40. This means that the net TBR higher than 1.0 could be expected with the supercritical-water-cooled blanket, whose temperature distribution in the breeder region would be optimized by following the coolant temperature, and where a coverage of the breeder region is assumed to be 70%. (author)

Standard Test Method for Application and Analysis of Solid State Track Recorder (SSTR) Monitors for Reactor Surveillance, E706(IIIB)

CERN Document Server

American Society for Testing and Materials. Philadelphia

2003-01-01

1.1 This test method describes the use of solid-state track recorders (SSTRs) for neutron dosimetry in light-water reactor (LWR) applications. These applications extend from low neutron fluence to high neutron fluence, including high power pressure vessel surveillance and test reactor irradiations as well as low power benchmark field measurement. (1) This test method replaces Method E 418. This test method is more detailed and special attention is given to the use of state-of-the-art manual and automated track counting methods to attain high absolute accuracies. In-situ dosimetry in actual high fluence-high temperature LWR applications is emphasized. 1.2 This test method includes SSTR analysis by both manual and automated methods. To attain a desired accuracy, the track scanning method selected places limits on the allowable track density. Typically good results are obtained in the range of 5 to 800 000 tracks/cm2 and accurate results at higher track densities have been demonstrated for some cases. (2) Trac...

Biogas production from solid pineapple waste

Energy Technology Data Exchange (ETDEWEB)

Tanticharoen, M.; Bhumiratana, S.; Tientanacom, S.; Pengsobha, L.

1984-01-01

Solid pineapple waste composed of shell and core was used as substrate in anaerobic fermentation producing CH4. The experiments were carried out using four 30-L vessels and no mixing, a 200-L plug-flow reactor, and a 5-cubic m stirred tank. Because of high acidity of the substrate, the loading rate is as low as 2.5 g dry solid added/L-day. The average gas yield is 0.3-0.5 L/g dry substrate. A pretreatment of wet solid with sludge effluent prior loading to the digester resulted in better stability of the biodigester than without pretreatment. These studies showed that loading rate can be much higher than those previously used. The 2-stage process was tested to determine a conversion efficiency of high loading and at much shorter reactor retention times. The results of the entire program indicated that biogas production from cannery pineapple waste is technically feasible.

Set-Up and Validation of a Dynamic Solid/Gas Bioreactor

KAUST Repository

Lloyd-Randol, Jennifer D.

2012-05-01

The limited availability of fossil resourses mandates the development of new energy vectors, which is one of the Grand Challenges of the 21st Century [1]. Biocatalytic energy conversion is a promising solution to meet the increased energy demand of industrialized societies. Applications of biocatalysis in the gas-phase are so far limited to production of fine chemicals and pharmaceuticals. However, this technology has the potential for large scale biocatalytic applications [2], e.g. for the formation of novel energy carriers. The so-called solid/gas biocatalysis is defined as the application of a biocatalyst immobilized on solid-phase support acting on gaseous substrates [3]. This process combines the advantages of bio-catalysis (green chemistry, mild reaction conditions, high specicity & selectivity) and heterogeneous dynamic gas-phase processes (low diffusion limitation, high conversion, simple scale-up). This work presents the modifications of a PID Microactivity Reference reactor in order to make it suitable for solid/gas biocatalysis. The reactor design requirements are based on previously published laboratory scale solid/gas systems with a feed of saturated vapors [4]. These vapors are produced in saturation flasks, which were designed and optimized during this project. Other modifications included relocation of the gas mixing chamber, redesigning the location and heating mechanism for the reactor tube, and heating of the outlet gas line. The modified reactor system was verified based on the Candida antarctica lipase B catalyzed transesterication of ethyl acetate with 1-hexanol to hexyl acetate and ethanol and results were compared to liquid-phase model reactions. Products were analyzed on line by a gas chromatograph with a flame ionization detector. C. antarc- tica physisorbed on silica particles produced a 50% conversion of hexanol at 40 C in the gas-phase. A commercial immobilized lipase from Iris Biotech produced 99% and 97% conversions of hexanol in

BWR type reactors

International Nuclear Information System (INIS)

Nakajima, Yoshitaka

1983-01-01

Purpose: To decrease the control rod exchanging frequency by increasing the working life of control rods for ordinary operation with large neutron irradiation dose, to thereby decrease the exposure dose for operators performing exchanging work, as well as decrease the amount of radioactive wastes resulted upon exchange of the control rods. Constitution: Hafnium solid metal is employed as the neutron absorber of control rods for usual operation inserted into and withdrawn from fuel assemblies for the reactor power control over the entire cycle of the ordinary reactor operation and boron carbide powder is employed as the neutron absorber for emergency control rods to be inserted between the fuel assemblies only upon reactor scram or shutdown, whereby the working life of the control rods for ordinary reactor operation with greater neutron irradiation dose can be improved. Accordingly, the control rod exchanging frequency can be reduced to decrease the exposure dose to the operator for conducting the exchanging work. (Yoshihara, H.)

Current research work at the TRIGA reactor in Ljubljana

International Nuclear Information System (INIS)

Najzer, M.; Dimic, V.

1978-01-01

The research programmes at this TRIGA reactor cover quite broad and different research fields. They can be grouped in the following topics: reactor dynamics and operation, neutron activation analysis, solid state physics research, reactor dosimetry, radiography and fuel burn-up determination. In this presentation a short overview is given of those investigations which are not described in detail in separate papers

Process modeling of a reversible solid oxide cell (r-SOC) energy storage system utilizing commercially available SOC reactor

International Nuclear Information System (INIS)

Mottaghizadeh, Pegah; Santhanam, Srikanth; Heddrich, Marc P.; Friedrich, K. Andreas; Rinaldi, Fabio

2017-01-01

Highlights: • An electric energy storage system was developed based on a commercially available SOC reactor. • Heat generated in SOFC mode of r-SOC is utilized in SOEC operation of r-SOC using latent heat storage. • A round trip efficiency of 54.3% was reached for the reference system at atmospheric pressure. • An improved process system design achieved a round-trip efficiency of 60.4% at 25 bar. - Abstract: The increase of intermittent renewable energy contribution in power grids has urged us to seek means for temporal decoupling of electricity production and consumption. A reversible solid oxide cell (r-SOC) enables storage of surplus electricity through electrochemical reactions when it is in electrolysis mode. The reserved energy in form of chemical compounds is then converted to electricity when the cell operates as a fuel cell. A process system model was implemented using Aspen Plus® V8.8 based on a commercially available r-SOC reactor experimentally characterized at DLR. In this study a complete self-sustaining system configuration is designed by optimal thermal integration and balance of plant. Under reference conditions a round trip efficiency of 54.3% was achieved. Generated heat in fuel cell mode is exploited by latent heat storage tanks to enable endothermic operation of reactor in its electrolysis mode. In total, out of 100 units of thermal energy stored in heat storage tanks during fuel cell mode, 90% was utilized to offset heat demand of system in its electrolysis mode. Parametric analysis revealed the significance of heat storage tanks in thermal management even when reactor entered its exothermic mode of electrolysis. An improved process system design demonstrates a system round-trip efficiency of 60.4% at 25 bar.

Niobium carbide synthesis by solid-gas reaction using a rotating cylinder reactor

International Nuclear Information System (INIS)

Fontes, F.A.O.; Gomes, K.K.P.; Oliveira, S.A.; Souza, C.P.; Sousa, J.F.; Rio Grande do Norte Univ., Natal, RN

2004-01-01

A rotating cylinder reactor was designed for the synthesis of niobium carbide powders at 1173 K. Niobium carbide, NbC, was prepared by carbothermal reduction starting from commercial niobium pentoxide powders. The reactor was heated using a custom-made, two-part, hinged, electric furnace with programmable temperature control. The design and operational details of the reactor are presented. The longitudinal temperature gradient inside the reactor was determined. Total reaction time was monitored by a gas chromatograph equipped with an FID detector for determination of methane concentrations. The results show that time of reaction depended on rotation speed. NbC was also prepared in a static-bed alumina reactor using the same conditions as in the previous case. The niobium carbide powders were characterized by X-ray diffraction and compared with commercially available products. Morphological, particle size distribution and surface area analyses were obtained using SEM, LDPS and BET, respectively. Therefore, the present study offers a significant technological contribution to the synthesis of NbC powders in a rotating cylinder reactor. (author)

Argentinean activities related to Fast Reactors

International Nuclear Information System (INIS)

Azpitarte, Osvaldo

2012-01-01

CNEA objectives in the area of Generation IV nuclear reactors: Implement a programme for the monitoring of the global progress of new technologies for Generation IV nuclear reactors and their fuel cycles, in order to generate and assess associated lines of R&D. – Perform studies and evaluations for defining the Generation IV line or lines on which CNEA would be interested; – Promote the participation on specific international projects; – Implementation of experimental facilities

Safety assessments relating to the use of new fuels in research reactors: application to the case of FRM 2 reactor fuel

International Nuclear Information System (INIS)

Abou Yehia, H.; Bars, G.; Tran Dai

2001-01-01

After giving a brief reminder of the procedure applied in France for the licensing of the use of a new fuel type or design in a research reactor, we outline the main safety aspects associated with such a modification. Finally, by way of an example, we focus on the safety assessment relating to the IRIS irradiation device used in SILOE reactor, in particular for the qualification of the fuel dedicated to FRM II reactor of the Technical University of Munich. This qualification was carried out on a U 3 Si 2 fuel plate enriched to about 90 % in weight of 235 U and containing 1.5 g of uranium per cm 3 . The evaluation performed by the IPSN for GRS did not call into question the choice of U 3 Si 2 fuel plates for the FRM-II reactor. (authors)

Ultrasound periodic inspections of reactor pressure vessels

International Nuclear Information System (INIS)

Haniger, L.

1980-01-01

Two versions are described of ultrasonic equipment for periodic inspections of reactor pressure vessels. One uses the principle of exchangeable programmators with solid-state logic while the other uses programmable logic with semiconductor memories. The equipment is to be used for inspections of welded joints on the upper part of the V-1 reactor pressure vessel. (L.O.)

PLUTONIUM METALLIC FUELS FOR FAST REACTORS

Energy Technology Data Exchange (ETDEWEB)

STAN, MARIUS [Los Alamos National Laboratory; HECKER, SIEGFRIED S. [Los Alamos National Laboratory

2007-02-07

Early interest in metallic plutonium fuels for fast reactors led to much research on plutonium alloy systems including binary solid solutions with the addition of aluminum, gallium, or zirconium and low-melting eutectic alloys with iron and nickel or cobalt. There was also interest in ternaries of these elements with plutonium and cerium. The solid solution and eutectic alloys have most unusual properties, including negative thermal expansion in some solid-solution alloys and the highest viscosity known for liquid metals in the Pu-Fe system. Although metallic fuels have many potential advantages over ceramic fuels, the early attempts were unsuccessful because these fuels suffered from high swelling rates during burn up and high smearing densities. The liquid metal fuels experienced excessive corrosion. Subsequent work on higher-melting U-PuZr metallic fuels was much more promising. In light of the recent rebirth of interest in fast reactors, we review some of the key properties of the early fuels and discuss the challenges presented by the ternary alloys.

TA-2 Water Boiler Reactor Decommissioning Project

International Nuclear Information System (INIS)

Durbin, M.E.; Montoya, G.M.

1991-06-01

This final report addresses the Phase 2 decommissioning of the Water Boiler Reactor, biological shield, other components within the biological shield, and piping pits in the floor of the reactor building. External structures and underground piping associated with the gaseous effluent (stack) line from Technical Area 2 (TA-2) Water Boiler Reactor were removed in 1985--1986 as Phase 1 of reactor decommissioning. The cost of Phase 2 was approximately $623K. The decommissioning operation produced 173 m 3 of low-level solid radioactive waste and 35 m 3 of mixed waste. 15 refs., 25 figs., 3 tabs

Measurements at the RA Reactor related to the VISA-2 project - Part 1, Start-up of the RA reactor and measurement of new RA reactor core parameters

International Nuclear Information System (INIS)

Markovic, H.

1962-07-01

The objective of the measurements was determining the neutron flux in the RA reactor core. Since the number of fuel channels is increased from 56 to 68 within the VISA-2 project, it was necessary to attain criticality of the RA reactor and measure the neutron flux properties. The 'program of RA reactor start-up' has been prepared separately and it is included in this report. Measurements were divided in two phases. First phase was measuring of the neutron flux after the criticality was achieved but at zero power. During phase two measurements were repeated at several power levels, at equilibrium xenon poisoning. This report includes experimental data of flux distributions and absolute values of the thermal and fast neutron flux in the RA reactor experimental channels and values of cadmium ratio for determining the neutron epithermal flux. Data related to calibration of regulatory rods for cold un poisoned core are included [sr

A Review on the Potential Use of Austenitic Stainless Steels in Nuclear Fusion Reactors

Science.gov (United States)

Şahin, Sümer; Übeyli, Mustafa

2008-12-01

Various engineering materials; austenitic stainless steels, ferritic/martensitic steels, vanadium alloys, refractory metals and composites have been suggested as candidate structural materials for nuclear fusion reactors. Among these structural materials, austenitic steels have an advantage of extensive technological database and lower cost compared to other non-ferrous candidates. Furthermore, they have also advantages of very good mechanical properties and fission operation experience. Moreover, modified austenitic stainless (Ni and Mo free) have relatively low residual radioactivity. Nevertheless, they can't withstand high neutron wall load which is required to get high power density in fusion reactors. On the other hand, a protective flowing liquid wall between plasma and solid first wall in these reactors can eliminate this restriction. This study presents an overview of austenitic stainless steels considered to be used in fusion reactors.

Laser or charged-particle-beam fusion reactor with direct electric generation by magnetic flux compression

International Nuclear Information System (INIS)

Lasche, G.P.

1988-01-01

A method for recovering energy in an inertial confinement fusion reactor having a reactor chamber and a sphere forming means positioned above an opening in the reactor chamber is described, comprising: embedding a fusion target fuel capsule having a predetermined yield in the center of a hollow solid lithium tube and subsequently embedding the hollow solid lithium tube in a liquid lithium medium; using the sphere forming means for forming the liquid lithium into a spherical shaped liquid lithium mass having a diameter smaller than the length of the hollow solid lithium tube with the hollow solid lithium tube being positioned along a diameter of the spherical shaped mass, providing the spherical shaped liquid lithium mass with the fusion fuel target capsule and hollow solid lithium tube therein as a freestanding liquid lithium shaped spherical shaped mass without any external means for maintaining the spherical shape by dropping the liquid lithium spherical shaped mass from the sphere forming means into the reactor chamber; producing a magnetic field in the reactor chamber; imploding the target capsule in the reactor chamber to produce fusion energy; absorbing fusion energy in the liquid lithium spherical shaped mass to convert substantially all the fusion energy to shock induced kinetic energy of the liquid lithium spherical shaped mass which expands the liquid lithium spherical shaped mass; and compressing the magnetic field by expansion of the liquid lithium spherical shaped mass and recovering useful energy

A new model for the in-reactor corrosion of zirconium alloys

International Nuclear Information System (INIS)

Cox, B.

1997-01-01

Previous models for the in-reactor corrosion of zirconium alloys have assumed that the mechanism is a completely solid-state diffusion process, determined by the growth and breakdown of the protective oxide film. In-reactor kinetics have been related to out-reactor kinetics with the oxide-metal interface temperature calculated from effects of heat flux. Recent experimental results have suggested that oxide dissolution and reprecipitation may be a major process leading to the formation of thick porous oxide films in-reactor. The model described here is based on the dissolution of primary recoil tracks in the oxide as the primary process distinguishing in-reactor from out-reactor corrosion. The consequences of such a model would be a very different microscopic morphology of in-reactor and out-reactor thick films, a significant irradiation effect on non-heat transfer surfaces, and a change in the kinetics of the overall process. This model should be equally applicable to PWR and BWR water chemistries because of the amphoteric nature of ZrO 2 , and the effects of LiOH should operate by an essentially identical mechanism. A reciprocal rate equation should fit these processes and with additive terms seems capable of accommodating all water chemistry effects, except for discontinuous processes such as nodular corrosion. (author). 60 refs, 6 figs

Analytical study of solids-gas two phase flow

International Nuclear Information System (INIS)

Hosaka, Minoru

1977-01-01

Fundamental studies were made on the hydrodynamics of solids-gas two-phase suspension flow, in which very small solid particles are mixed in a gas flow to enhance the heat transfer characteristics of gas cooled high temperature reactors. Especially, the pressure drop due to friction and the density distribution of solid particles are theoretically analyzed. The friction pressure drop of two-phase flow was analyzed based on the analytical result of the single-phase friction pressure drop. The calculated values of solid/gas friction factor as a function of solid/gas mass loading are compared with experimental results. Comparisons are made for Various combinations of Reynolds number and particle size. As for the particle density distribution, some factors affecting the non-uniformity of distribution were considered. The minimum of energy dispersion was obtained with the variational principle. The suspension density of particles was obtained as a function of relative distance from wall and was compared with experimental results. It is concluded that the distribution is much affected by the particle size and that the smaller particles are apt to gather near the wall. (Aoki, K.)

Future prospects of reactor Ra at VINCA institute

International Nuclear Information System (INIS)

Davidovic, M.; Babic-Stojic, B.; Dobrijevic, R.

1997-01-01

Reactor RA at Nuclear Research Institute Vinca belongs to a group of the medium thermal neutron flux reactors, according to classification at end of nineties. At the beginning reactor RA has been used as a powerful source of neutrons and gamma-quanta for various experiments (interaction of neutrons and gamma-quanta with materials) and for production of artificial radioactive materials for commercial use. Very successful utilization of this neutron spectrum has been in its use for structural studies of crystal materials and liquid metals, for magnetic structure studies of various magnetic materials, as well as, dynamic properties of ferro magnetics, ferroelectrics, etc. This kind of spectrometers still exist at reactor RA and with an improved detection system could be used again if reactor starts functioning. Besides this, a part of activity was devoted to construction of neutron guide tubes for thermal neutrons and this could also be accomplished relatively easy in the future. A part of the activities of the reactor should in the future be devoted to the training of students in the field of solid state physics and nuclear physics. Particular attention will be paid to the use of established technologies in production of radioactive isotopes and a new class of isotopes for custom use will be developed as well as highly commercial and prospective products (silicon doping, radiography, etc.). (author)

Sterilization of swine wastewater treated by anaerobic reactors using UV photo-reactors

Directory of Open Access Journals (Sweden)

Erlon Lopes Pereira

2014-09-01

Full Text Available The use of ultraviolet radiation is an established procedure with growing application forthe disinfection of contaminated wastewater. This study aimed to evaluate the efficiency of artificial UV radiation, as a post treatment of liquid from anaerobic reactors treating swine effluent. The UV reactors were employed to sterilize pathogenic microorganisms. To this end, two photo-reactors were constructed using PVC pipe with100 mm diameter and 1060 mmlength, whose ends were sealed with PVC caps. The photo-reactors were designed to act on the liquid surface, as the lamp does not get into contact with the liquid. To increase the efficiency of UV radiation, photo-reactors were coated with aluminum foil. The lamp used in the reactors was germicidal fluorescent, with band wavelength of 230 nm, power of 30 Watts and manufactured by Techlux. In this research, the HRT with the highest removal efficiency was 0.063 days (90.6 minutes, even treating an effluent with veryhigh turbidity due to dissolved solids. It was concluded that the sterilization method using UV has proved to be an effective and appropriate process, among many other procedures.

IAEA activities related to research reactor fuel conversion and spent fuel return programs

International Nuclear Information System (INIS)

Goldman, Ira N.; Adelfang, Pablo; Ritchie, Iain G.

2005-01-01

The IAEA has been involved for more than twenty years in supporting international nuclear non-proliferation efforts associated with reducing the amount of highly enriched uranium (HEU) in international commerce. IAEA projects and activities have directly supported the Reduced Enrichment for Research and Test Reactors (RERTR) programme, as well as directly associated efforts to return research reactor fuel to the country where it was originally enriched. IAEA efforts have included the development and maintenance of several data bases with information related to research reactors and research reactor spent fuel inventories that have been essential in planning and managing both RERTR and spent fuel return programmes. Other IAEA regular budget programs have supported research reactor fuel conversion from HEU to low enriched uranium (LEU), and in addressing issues common to many member states with spent fuel management problems and concerns. The paper briefly describes IAEA involvement since the early 1980's in these areas, including regular budget and Technical Co-operation programme activities, and focuses on efforts in the past five years to continue to support and accelerate U.S. and Russian research reactor spent fuel return programmes. (author)

Szilard-Chalmers effect in solid H I O{sub 4}. 2 H{sub 2} O by neutron irradiation (source-reactor)

Energy Technology Data Exchange (ETDEWEB)

Takriti, S [radiochemistry laboratory, syrian atomic energy commission P.O. Box 6091 Damascus, (Syrian Arab Republic)

1995-10-01

The Szilard-Chalmers effect in solid periodic acid was investigated. In order to study the initial distribution of {sup 128I} o{sub 4} as a function of neutron flux, samples were irradiated utilizing both neutron source ({sup 241} Am-Be), the manual vertical irradiation channel and the thermal column of ET-R R-1 research reactor in Egypt. The initial retention reached a maximum of 40% after 120 minutes at 5.5 x 10 {sup 8} n s{sup -1} cm {sup -2}. The data was analysed using first order reaction. As a result, the activation Ko= 2.82 x 10 {sup 11} (S{sup -1}), respectively. Kinetics comparison of the dehydration and irradiation reactions for this solid showed disorder in the crystallographic form. Such disorder may be the result of dehydration or irradiation reactions, where the loss of water molecule will lead to formation of vacancies which, in turn, are responsible for the distribution process. 6 figs., 1 tab.

Taylor flow hydrodynamics in gas-liquid-solid micro reactors

NARCIS (Netherlands)

Warnier, M.J.F.

2009-01-01

Chemical reactions in which a gas phase component reacts with a liquid phase omponent at the surface of a solid catalyst are often encountered in chemical industry. The rate of such a gas-liquid-solid reaction is often limited by the mass transfer rate of the gas phase component, which depends on

Volume reduction and solidification of liquid and solid low-level radioactive waste

International Nuclear Information System (INIS)

May, J.R.

1979-01-01

This paper presents a brief background of the development of a method of radioactive waste volume reduction using a unique fluidized bed calciner/incinerator. The volume reduction system is capable of processing a variety of liquid chemical wastes, spent ion exchange resin beads, filter treatment sludges, contaminated lubricating oils, and miscellaneous combustible solids such as paper, rags, protective clothing, wood, etc. All of these wastes are processed in one chemical reaction vessel. Detailed process data is presented that shows the system is capable of reducing the total volume of disposable radioactive waste generated by light water reactors by a factor of 10. Equally important to reducing the volume of power reactor radwaste is the final form of the stored or disposable radwaste. This paper also presents process data related to a new radwaste solidification system, presently being developed, that is particularly suited for immobilizing the granular solids and ashes resulting from volume reduction by calcination and/or incineration

Status of EC solid breeder blanket designs and R and D for demo fusion reactors

International Nuclear Information System (INIS)

Proust, E.; Anzidei, L.; Moons, F.

1994-01-01

Within the European Community Fusion Technology Program two solid breeder blankets for a DEMO reactor are being developed. The two blankets have various features in common: helium as coolant and as tritium purge gas, the martensitic steel MANET as structural material and beryllium as neutron multiplier. The configurations of the two blankets are however different: in the B.I.T. (Breeder Inside Tube) concept the breeder materials are LiAlO 2 or Li 2 ZrO 3 in the form of annular pellets contained in tubes surrounded by beryllium blocks, the coolant helium being outside the tubes, whereas in the B.O.T. (Breeder out of Tube) the breeder and multiplier material are Li 4 SiO 4 and beryllium pebbles forming a mixed bed placed outside the tubes containing the coolant helium. The main critical issues for both blankets are the behavior of the breeder ceramics and of beryllium under irradiation and the tritium control. Other issues are the low temperature irradiation induced embrittlement of MANET, the mechanical effects caused by major plasma disruptions, and safety and reliability. The R and D work concentrate on these issues. The development of martensitic steels including MANET is part of a separate program. Breeder ceramics and beryllium irradiations have been so far performed for conditions which do not cover the peak values injected in the DEMO blankets. Further irradiations in thermal reactors and in fast reactors, especially for beryllium, are required. An effective tritium control requires the development of permeation barriers and/or of methods of oxidation of the tritium in the main helium cooling systems. First promising results have been obtained also in field of mechanical effects from plasma disruptions and safety and reliability, however further work is required in the reliability field and to validate the codes for the calculations of the plasma disruption effects. (authors). 8 figs., 2 tabs., 53 refs

Static fuel molten salt reactors - simpler, cheaper and safer

International Nuclear Information System (INIS)

Scott, Ian

2015-01-01

refuelling. These reactors are relatively straightforward simplifications of conventional solid fuelled reactors. The fuel assemblies are similar both in design and in construction materials. Replacement of water as coolant with a (fissile free) molten salt removes explosion risks from the reactor containment. There are many possible designs of reactors utilising this form of fuel. One design, a fast spectrum actinide burning reactor called the Stable Salt Reactor has been developed to the stage where realistic capital cost estimates can be made. This was done independently of Moltex Energy by Atkins Ltd. The capital cost (UK prices) for a 1GWe nuclear island was estimated (rough order of magnitude, reflecting the early stage of the design) as £718 per kW, a small fraction of the cost for any conventional nuclear island. Of particular interest to this conference may be the potential for a thorium breeding version of the reactor. Simply replacing the coolant salt with one based on ThF 4 turns the reactor into an efficient 233 U breeder. The basic principles of this version will be described during the talk. (author)

FLUIDDYNAMIC ASPECTS OF GAS-PHASE ETHYLENE POLYMERIZATION REACTOR DESIGN

Directory of Open Access Journals (Sweden)

Guardani R.

1998-01-01

Full Text Available The relative importance of design variables affecting the fluiddynamic behavior of a fluidized bed reactor for the gas-phase ethylene polymerization is discussed, based on mathematical modeling. The three-phase bubbling fluidized bed model is based on axially distributed properties for the bubble, cloud and emulsion phases, combined with correlations for population balance and entrainment. Under the operating conditions adopted in most industrial processes, the reactor performance is affected mainly by the reaction rate and solids entrainment. Simulation results indicate that an adequate design of the freeboard and particle collecting equipment is of primary importance in order to produce polymeric particles with the desired size distribution, as well as to keep entrainment and catalyst feed rates at adequate levels.

Re-fermentation of washed spent solids from batch hydrogenogenic fermentation for additional production of biohydrogen from the organic fraction of municipal solid waste.

Science.gov (United States)

Muñoz-Páez, Karla M; Ríos-Leal, Elvira; Valdez-Vazquez, Idania; Rinderknecht-Seijas, Noemí; Poggi-Varaldo, Héctor M

2012-03-01

In the first batch solid substrate anaerobic hydrogenogenic fermentation with intermittent venting (SSAHF-IV) of the organic fraction of municipal solid waste (OFMSW), a cumulative production of 16.6 mmol H(2)/reactor was obtained. Releases of hydrogen partial pressure first by intermittent venting and afterward by flushing headspace of reactors with inert gas N(2) allowed for further hydrogen production in a second to fourth incubation cycle, with no new inoculum nor substrate nor inhibitor added. After the fourth cycle, no more H(2) could be harvested. Interestingly, accumulated hydrogen in 4 cycles was 100% higher than that produced in the first cycle alone. At the end of incubation, partial pressure of H(2) was near zero whereas high concentrations of organic acids and solvents remained in the spent solids. So, since approximate mass balances indicated that there was still a moderate amount of biodegradable matter in the spent solids we hypothesized that the organic metabolites imposed some kind of inhibition on further fermentation of digestates. Spent solids were washed to eliminate organic metabolites and they were used in a second SSAHF-IV. Two more cycles of H(2) production were obtained, with a cumulative production of ca. 2.4 mmol H(2)/mini-reactor. As a conclusion, washing of spent solids of a previous SSAHF-IV allowed for an increase of hydrogen production by 15% in a second run of SSAHF-IV, leading to the validation of our hypothesis. Copyright © 2011 Elsevier Ltd. All rights reserved.

IAEA activities related to research reactor fuel conversion and spent fuel return programmes

International Nuclear Information System (INIS)

Ritchie, I.G.; Adelfang, P.; Goldman, I.N.

2004-01-01

Full text: The IAEA has been involved for more than twenty years in supporting international nuclear non-proliferation efforts associated with reducing the amount of highly enriched uranium (HEU) in international commerce. IAEA projects and activities have directly supported the Reduced Enrichment for Research and Test Reactors (RERTR) programme, as well as directly associated efforts to return research reactor fuel to the country of origin where it was originally enriched. IAEA efforts have included the development and maintenance of several data bases with information related to research reactors and research reactor spent fuel inventories that have been essential in planning and managing both RERTR and spent fuel return programmes. Other IAEA regular budget programmes have supported research reactor fuel conversion from HEU to low enriched uranium, and in addressing issues common to many member states with spent fuel management problems and concerns. The paper briefly describes IAEA involvement since the early 1980's in these areas, including regular budget and Technical Co-operation programme activities, and focuses on efforts in the past five years to continue to support and accelerate U.S. and Russian research reactor spent fuel return programmes. It is hoped that an announcement of the extension of the U.S. Acceptance Programme, which is expected in the very near future, will facilitate the life extensions of many productive TRIGA reactors around the world. (author)

Related activities on management of ageing of Dalat Research Reactor

Energy Technology Data Exchange (ETDEWEB)

Lam, Pham Van [Reactor Dept., Nuclear Research Institute, Dalat (Viet Nam)

1998-10-01

The Dalat Nuclear Research Reactor (DNRR) is a pool type research reactor which was reconstructed in 1982 from the previous 250 kW TRIGA-MARK II reactor. The reactor core, the control and instrumentation system, the primary and secondary cooling systems as well as other associated systems were newly designed and installed. The renovated reactor reached its initial criticality in November 1983 and attained its nominal power of 500 kW in February 1984. Since then DNRR has been operated safely. Retained structures of the former reactor such as the reactor aluminum tank, the graphite reflector, the thermal column, the horizontal beam tubes and the radiation concrete shielding are 35 years old. During the recent years, in-service inspection has been carried out, the reactor control and instrumentation system were renovated due to ageing and obsolescence of its components, reactor general inspection and refurbishment were performed. Efforts are being made to cope with ageing of old reactor components to maintain safe operation of the DNRR. (author)

Simultaneous measurement of local particle movement, solids concentrations and bubble properties in fluidized bed reactors using a novel fiber optical technique

Energy Technology Data Exchange (ETDEWEB)

Tayebi, Davoud

1999-12-31

This thesis develops a new method for simultaneous measurements of local flow properties in highly concentrated multiphase flow systems such as gas-solid fluidized bed reactors. The method is based on fiber optical technique and tracer particles. A particle present in the measuring volume in front of the probe is marked with a fluorescent dye. A light source illuminates the particles and the detecting fibres receive reflected light from uncoated particles and fluorescent light from the tracer particle. Using optical filters, the fluorescent light can be distinguished and together with a small fraction of background light from uncoated particles can be used for determination of local flow properties. Using this method, one can simultaneously measure the local movement of a single tracer particle, local bubble properties and the local solids volume fractions in different positions in the bed. The method is independent of the physical properties of the tracer particles. It is also independent of the local solids concentrations in the range of 0 to 60 vol.-%, but is mainly designed for highly concentrated flow systems. A computer programme that uses good signals from at least three sensors simultaneously to calculate the tracer particle velocity in two dimensions have been developed. It also calculates the bubble properties and local solids volume fractions from the same time series. 251 refs., 150 figs., 5 tabs.

Simultaneous measurement of local particle movement, solids concentrations and bubble properties in fluidized bed reactors using a novel fiber optical technique

Energy Technology Data Exchange (ETDEWEB)

Tayebi, Davoud

1998-12-31

This thesis develops a new method for simultaneous measurements of local flow properties in highly concentrated multiphase flow systems such as gas-solid fluidized bed reactors. The method is based on fiber optical technique and tracer particles. A particle present in the measuring volume in front of the probe is marked with a fluorescent dye. A light source illuminates the particles and the detecting fibres receive reflected light from uncoated particles and fluorescent light from the tracer particle. Using optical filters, the fluorescent light can be distinguished and together with a small fraction of background light from uncoated particles can be used for determination of local flow properties. Using this method, one can simultaneously measure the local movement of a single tracer particle, local bubble properties and the local solids volume fractions in different positions in the bed. The method is independent of the physical properties of the tracer particles. It is also independent of the local solids concentrations in the range of 0 to 60 vol.-%, but is mainly designed for highly concentrated flow systems. A computer programme that uses good signals from at least three sensors simultaneously to calculate the tracer particle velocity in two dimensions have been developed. It also calculates the bubble properties and local solids volume fractions from the same time series. 251 refs., 150 figs., 5 tabs.

Basic research on high-uranium density fuels for research and test reactors

International Nuclear Information System (INIS)

Ugajin, M.; Itoh, A.; Akabori, M.

1992-01-01

High-uranium density fuels, uranium silicides (U 3 Si 2 , U 3 Si) and U 6 Me-type uranium alloys (Me = Fe, Mn, Ni), were prepared and examined metallurgically as low-enriched uranium (LEU) fuels for research and test reactors. Miniature aluminum-dispersion plate-type fuel (miniplate) and aluminum-clad disk-type fuel specimens were fabricated and subjected to the neutron irradiation in JMTR (Japan Materials Testing Reactor). Fuel-aluminum compatibility tests were conducted to elucidate the extent of reaction and to identify reaction products. The relative stability of the fuels in an aluminum matrix was established at 350degC or above. Experiments were also performed to predict the chemical form of the solid fission-products in the uranium silicide (U 3 Si 2 ) simulating a high burnup anticipated for reactor service. (author)

Biological treatment of soils contaminated with hydrophobic organics using slurry and solid phase techniques

International Nuclear Information System (INIS)

Cassidy, D.P.; Irvine, R.L.

1995-01-01

Both slurry-phase and solid-phase bioremediation are effective ex situ soil decontamination methods. Slurry is energy intensive relative to solid-phase treatment, but provides homogenization and uniform nutrient distribution. Limited contaminant bioavailability at concentrations above the required cleanup level reduces biodegradation rates and renders solid phase bioremediation more cost effective than complete treatment in a bioslurry reactor. Slurrying followed by solid-phase bioremediation combines the advantages and minimizes the weaknesses of each treatment method when used alone. A biological treatment system consisting of slurrying followed by aeration in solid phase bioreactors was developed and tested in the laboratory using a silty clay load contaminated with diesel fuel. The first set of experiments was designed to determine the impact of the water content and mixing time during slurrying on the ate and extent of contaminant removal in continuously aerated solid phase bioreactors. The second set of experiments compared the volatile and total diesel fuel removal in solid phase bioreactors using periodic and continuous aeration strategies

Synthesis and characterization of tungsten carbide doped cobalt via gas-solid reaction in rotary bed reactor; Sintese e caracterizacao de carbeto de tungstenio dopado com cobalto via reacao gas-solido em reator de leito rotativo

Energy Technology Data Exchange (ETDEWEB)

Tertuliano, R.S.C.; Araujo, C.P.B. de; Frota, A.V.V.M.; Moriyama, A.L.L.; Souza, C.P. de, E-mail: ruasavio@hotmail.com [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Departamento de Engenharia Quimica

2016-07-01

The search for materials with high added value, high applicability and sustainability, motivates innovations in all areas of engineering. In this context, so-called doped carbides, ceramic and metal compounds are included. This work proposes the synthesis and characterization of tungsten carbide doped cobalt (WC-Co) through the gas-solid reaction in a rotating bed reactor. The production stages of the material are: precursor synthesis by wetting, drying at 80 deg C, characterization of the precursor by MEV, DRX and FRX, gas-solid reaction at 750 deg C in a reducing atmosphere of CH{sub 4} / H{sub 2} in a rotary reactor at 34 rpm and characterization of the reaction product by the techniques already mentioned. The results showed that tungsten carbide powders were produced with cobalt inserted into the structure, with high surface area, nanometric grains and with potential for applications in the areas of catalysis, reactors and fuel cells, showing the relevance of this type of research.

Constitutive relations for nuclear reactor core materials

International Nuclear Information System (INIS)

Zaverl, F. Jr.; Lee, D.

1978-01-01

A strain rate dependent constitutive equation is proposed which is capable of describing inelastic deformation behavior of anisotropic metals, such as Zircaloys, under complex loading conditions. The salient features of the constitutive equations are that they describe history dependent inelastic deformation behaviour of anisotropic metals under three-dimensional stress states in the presence of fast neutron flux. It is shown that the general form of the constitutive relations is consistent with experimental observations made under both unirradiated and irradiated conditions. The utility of the model is demonstrated by examining the analytical results obtained for a segment of tubing undergoing different loading histories in a reactor. (Auth.)

Performance evaluation of full scale UASB reactor in treating stillage wastewater

Directory of Open Access Journals (Sweden)

A.Mirsepasi , H. R. Honary , A. R. Mesdaghinia, A. H. Mahvi , H. Vahid , H. Karyab

2006-04-01

Full Text Available Upflow anaerobic sludge blanket (UASB reactors have been widely used for treatment of industrial wastewater. In this study two full-scale UASB reactors were investigated. Volume of each reactor was 420 m3. Conventional parameters such as pH, temperature and efficiency of COD, BOD, TOC removal in each reactor were investigated. Also several initial parameters in designing and operating of UASB reactors, such as upflow velocity, organic loading rate (OLR and hydraulic retention time were investigated. After modifying in operation conditions in UASB-2 reactor, average COD removal efficiency at OLR of 10–11 kg COD / m3 day was 55 percent. In order to prevent solids from settling, upflow velocity was increased to 0.35 m/h. Also to prevent solids from settling, the hydraulic retention time of wastewater in UASB-2 reactor was increased from 200 to 20 hours. This was expected that with good operation of UASB-2 reactor and with expanding of granules in the bed of the reactor, COD removal efficiency will be increased to more than 80 percent. But, because of deficiency on granulation and operation in UASB-2 reactor, this was not achieved. COD removal efficiency in the UASB-1 reactor was little. To enhance COD efficiency of UASB-1 reactor, several parameters were needed to be changed. These changes included enhancing of OLRs and upflow velocity, decreasing hydraulic retention time and operating with new sludge.

Evaluation and modeling of biochemical methane potential (BMP) of landfilled solid waste: a pilot scale study

DEFF Research Database (Denmark)

Bilgili, M Sinan; Demir, Ahmet; Varank, Gamze

2009-01-01

The main goal of this study was to present a comparison of landfill performance with respect to solids decomposition. Biochemical methane potential (BMP) test was used to determine the initial and the remaining CH(4) potentials of solid wastes during 27 months of landfilling operation in two pilot...... scale landfill reactors. The initial methane potential of solid wastes filled to the reactors was around 0.347 L/CH(4)/g dry waste, which decreased with operational time of landfill reactors to values of 0.117 and 0.154 L/CH(4)/g dry waste for leachate recirculated (R1) and non-recirculated (R2...

Anaerobic digestion of solid waste in RAS: Effect of reactor type on the biochemical acidogenic potential (BAP) and assessment of the biochemical methane potential (BMP) by a batch assay

DEFF Research Database (Denmark)

Suhr, Karin Isabel; Letelier-Gordo, Carlos Octavio; Lund, Ivar

2015-01-01

the biochemical acidogenic potential of solid waste from juvenile rainbow trout was evaluated by measuring the yield of volatile fatty acids (VFA) during anaerobic digestion by batch or fed-batch reactor operation at hydrolysis time (HT) / hydraulic retention time (HRT) of 1, 5, or 10 days (and for batch......Anaerobic digestion is a way to utilize the potential energy contained in solid waste produced in recirculating aquaculture systems (RASs), either by providing acidogenic products for driving heterotrophic denitrification on site or by directly producing combustive methane. In this study...

Reactor protection system

International Nuclear Information System (INIS)

Fairbrother, D.B.; Lesniak, L.M.; Orgera, E.G.

1977-10-01

The report describes the reactor protection system (RPS-II) designed for use on Babcock and Wilcox 145-, later 177-, and 205-fuel assembly pressurized water reactors. In this system, relays in the trip logic have been replaced by solid state devices. A calculating module for the low DNBR, pump status, and offset trip functions has replaced the overpower trip (based on flow and imbalance), the power/RC pump trip, and the variable low-pressure trip. Included is a description of the changes from the present Oconee-type reactor protection system (RPS-I), a functional and hardware description of the calculating module, a description of the software programmed in the calculating module, and a discussion of the qualification program conducted to ensure that the degree of protection provided by RPS-II is not less than that provided by previously licensed systems supplied by B and W

Reproduction of the RA reactor fuel element fabrication

International Nuclear Information System (INIS)

Novakovic, M.

1961-12-01

This document includes the following nine reports: Final report on task 08/12 - testing the Ra reactor fuel element; design concept for fabrication of RA reactor fuel element; investigation of the microstructure of the Ra reactor fuel element; Final report on task 08/13 producing binary alloys with Al, Mo, Zr, Nb and B additions; fabrication of U-Al alloy; final report on tasks 08/14 and 08/16; final report on task 08/32 diffusion bond between the fuel and the cladding of the Ra reactor fuel element; Final report on task 08/33, fabrication of the RA reactor fuel element cladding; and final report on task 08/36, diffusion of solid state metals [sr

A new model for the in-reactor corrosion of zirconium alloys

Energy Technology Data Exchange (ETDEWEB)

Cox, B [University of Toronto, ON (Canada). Centre for Nuclear Engineering

1997-02-01

Previous models for the in-reactor corrosion of zirconium alloys have assumed that the mechanism is a completely solid-state diffusion process, determined by the growth and breakdown of the protective oxide film. In-reactor kinetics have been related to out-reactor kinetics with the oxide-metal interface temperature calculated from effects of heat flux. Recent experimental results have suggested that oxide dissolution and reprecipitation may be a major process leading to the formation of thick porous oxide films in-reactor. The model described here is based on the dissolution of primary recoil tracks in the oxide as the primary process distinguishing in-reactor from out-reactor corrosion. The consequences of such a model would be a very different microscopic morphology of in-reactor and out-reactor thick films, a significant irradiation effect on non-heat transfer surfaces, and a change in the kinetics of the overall process. This model should be equally applicable to PWR and BWR water chemistries because of the amphoteric nature of ZrO{sub 2}, and the effects of LiOH should operate by an essentially identical mechanism. A reciprocal rate equation should fit these processes and with additive terms seems capable of accommodating all water chemistry effects, except for discontinuous processes such as nodular corrosion. (author). 60 refs, 6 figs.

Studies on rate equations for defects in irradiated solids using the local analysis method

International Nuclear Information System (INIS)

Carvalho e Camargo, M.U. de.

1983-10-01

The void formation and swelling phenomenon in material for nuclear reactors structures, mainly for fast reactors, has been studied by several authors. A simple calculation covering the basic instance of radiation damage in irradiated solid solution, using the local analysis in rate theory is presented here. A simple description of pratical and fundamental interest for the complex problem of solid solution under irradiation is given. (Author) [pt

Hydrodynamics of the continuously filtering slurry reactor. Influence of load of solids and particle size distribution.

NARCIS (Netherlands)

Huizenga, P.; Kuipers, J.A.M.; van Swaaij, Willibrordus Petrus Maria

1997-01-01

Internal filtration in slurry bubble columns offers a possible solution to the filtration problems related to this reactor type. The applicability of the concept has already been demonstrated at full-scale for waste water treatment. Theoretical description of internal filtration is lacking, however.

Hydrodynamics of the continuously filtering slurry reactor. Influence of load of solids and particle size distribution

NARCIS (Netherlands)

Huizenga, P.; Kuipers, J.A.M.; van Swaaij, W.P.M.

1997-01-01

Internal filtration in slurry bubble columns offers a possible solution to the filtration problems related to this reactor type. The applicability of the concept has already been demonstrated at full-scale for waste water treatment. Theoretical description of internal filtration is lacking, however.

Comparison of different liquid anaerobic digestion effluents as inocula and nitrogen sources for solid-state batch anaerobic digestion of corn stover

International Nuclear Information System (INIS)

Xu Fuqing; Shi Jian; Lv Wen; Yu Zhongtang; Li Yebo

2013-01-01

Highlights: ► Compared methane production of solid AD inoculated with different effluents. ► Food waste effluent (FWE) had the largest population of acetoclastic methanogens. ► Solid AD inoculated with FWE produced the highest methane yield at F/E ratio of 4. ► Dairy waste effluent (DWE) was rich of cellulolytic and xylanolytic bacteria. ► Solid AD inoculated with DWE produced the highest methane yield at F/E ratio of 2. - Abstract: Effluents from three liquid anaerobic digesters, fed with municipal sewage sludge, food waste, or dairy waste, were evaluated as inocula and nitrogen sources for solid-state batch anaerobic digestion of corn stover in mesophilic reactors. Three feedstock-to-effluent (F/E) ratios (i.e., 2, 4, and 6) were tested for each effluent. At an F/E ratio of 2, the reactor inoculated by dairy waste effluent achieved the highest methane yield of 238.5 L/kgVS feed , while at an F/E ratio of 4, the reactor inoculated by food waste effluent achieved the highest methane yield of 199.6 L/kgVS feed . The microbial population and chemical composition of the three effluents were substantially different. Food waste effluent had the largest population of acetoclastic methanogens, while dairy waste effluent had the largest populations of cellulolytic and xylanolytic bacteria. Dairy waste also had the highest C/N ratio of 8.5 and the highest alkalinity of 19.3 g CaCO 3 /kg. The performance of solid-state batch anaerobic digestion reactors was closely related to the microbial status in the liquid anaerobic digestion effluents.

Comparison of different liquid anaerobic digestion effluents as inocula and nitrogen sources for solid-state batch anaerobic digestion of corn stover

Energy Technology Data Exchange (ETDEWEB)

Xu Fuqing; Shi Jian [Department of Food, Agricultural and Biological Engineering, Ohio State University, Ohio Agricultural Research and Development Center, 1680 Madison Ave., Wooster, OH 44691 (United States); Lv Wen; Yu Zhongtang [Department of Animal Sciences, Ohio State University, Columbus, OH 43210 (United States); Li Yebo, E-mail: li.851@osu.edu [Department of Food, Agricultural and Biological Engineering, Ohio State University, Ohio Agricultural Research and Development Center, 1680 Madison Ave., Wooster, OH 44691 (United States)

2013-01-15

Highlights: Black-Right-Pointing-Pointer Compared methane production of solid AD inoculated with different effluents. Black-Right-Pointing-Pointer Food waste effluent (FWE) had the largest population of acetoclastic methanogens. Black-Right-Pointing-Pointer Solid AD inoculated with FWE produced the highest methane yield at F/E ratio of 4. Black-Right-Pointing-Pointer Dairy waste effluent (DWE) was rich of cellulolytic and xylanolytic bacteria. Black-Right-Pointing-Pointer Solid AD inoculated with DWE produced the highest methane yield at F/E ratio of 2. - Abstract: Effluents from three liquid anaerobic digesters, fed with municipal sewage sludge, food waste, or dairy waste, were evaluated as inocula and nitrogen sources for solid-state batch anaerobic digestion of corn stover in mesophilic reactors. Three feedstock-to-effluent (F/E) ratios (i.e., 2, 4, and 6) were tested for each effluent. At an F/E ratio of 2, the reactor inoculated by dairy waste effluent achieved the highest methane yield of 238.5 L/kgVS{sub feed}, while at an F/E ratio of 4, the reactor inoculated by food waste effluent achieved the highest methane yield of 199.6 L/kgVS{sub feed}. The microbial population and chemical composition of the three effluents were substantially different. Food waste effluent had the largest population of acetoclastic methanogens, while dairy waste effluent had the largest populations of cellulolytic and xylanolytic bacteria. Dairy waste also had the highest C/N ratio of 8.5 and the highest alkalinity of 19.3 g CaCO{sub 3}/kg. The performance of solid-state batch anaerobic digestion reactors was closely related to the microbial status in the liquid anaerobic digestion effluents.

Reactor vessel decommissioning project. Final report

International Nuclear Information System (INIS)

Schoonen, D.H.

1984-09-01

This report describes a reactor vessel decommissioning project; it documents and explains the project objectives, scope, performance results, and sodium removal process. The project was successfully completed in FY-1983, within budget and without significant problems or adverse impact on the environment. Waste generated by the operation included the reactor vessel, drained sodium, and liquid, solid, and gaseous wastes which were significantly less than project estimates. Personnel radiation exposures were minimized, such that the project total was one-half the predicted exposure level. Except for the sodium removed, the material remaining in the reactor vessel is essentially the same as when the vessel arrived for processing

Changes in water chemistry and primary productivity of a reactor cooling reservoir (Par Pond)

International Nuclear Information System (INIS)

Tilly, L.J.

1975-01-01

Water chemistry and primary productivity of a reactor cooling reservoir have been studied for 8 years. Initially the primary productivity increased sixfold, and the dissolved solids doubled. The dissolved-solids increase appears to have been caused by additions of makeup water from the Savannah River and by evaporative concentration during the cooling process. As the dissolved-solids concentrations and the conductivity of makeup water leveled off, the primary productivity stabilized. Major cation and anion concentrations generally followed total dissolved solids through the increase and plateau; however, silica concentrations declined steadily during the initial period of increased plankton productivity. Standing crops of net seston and centrifuge seston did not increase during this initial period. The collective data show the effects of thermal input to a cooling reservoir, illustrate the need for limnological studies before reactor siting, and suggest the possibility of using makeup-water additions to power reactor cooling basins as a reservoir management tool

Responses of the biogas process to pulses of oleate in reactors treating mixtures of cattle and pig manure

DEFF Research Database (Denmark)

Nielsen, Henrik Bjørn; Ahring, Birgitte Kiær

2006-01-01

The effect of oleate on the anaerobic digestion process was investigated. Two thermophilic continuously stirred tank reactors (CSTR) were fed with mixtures of cattle and pig manure with different total solid (TS) and volatile solid (VS) content. The reactors were subjected to increasing pulses...

Reactor performance and energy analysis of solid state anaerobic co-digestion of dairy manure with corn stover and tomato residues.

Science.gov (United States)

Li, Yangyang; Xu, Fuqing; Li, Yu; Lu, Jiaxin; Li, Shuyan; Shah, Ajay; Zhang, Xuehua; Zhang, Hongyu; Gong, Xiaoyan; Li, Guoxue

2018-03-01

Anaerobic co-digestion is commonly believed to be benefical for biogas production. However, additional of co-substrates may require additional energy inputs and thus affect the overall energy efficiency of the system. In this study, reactor performance and energy analysis of solid state anaerobic digestion (SS-AD) of tomato residues with dairy manure and corn stover were investigated. Different fractions of tomato residues (0, 20, 40, 60, 80 and 100%, based on volatile solid weight (VS)) were co-digested with dairy manure and corn stover at 15% total solids. Energy analysis based on experimental data was conducted for three scenarios: SS-AD of 100% dairy manure, SS-AD of binary mixture (60% dairy manure and 40% corn stover, VS based), and SS-AD of ternary mixture (36% dairy manure, 24% corn stover, and 40% tomato residues, VS based). For each scenario, the energy requirements for individual process components, including feedstock collection and transportation, feedstock pretreatment, biogas plant operation, digestate processing and handling, and the energy production were examined. Results showed that the addition of 20 and 40% tomato residues increased methane yield compared to that of the dairy manure and corn stover mixture, indicating that the co-digestion could balance nutrients and improve the performance of solid-state anaerobic digestion. The energy required for heating substrates had the dominant effect on the total energy consumption. The highest volatile solids (VS) reduction (57.0%), methane yield (379.1 L/kg VS feed ), and net energy production were achieved with the mixture of 24% corn stover, 36% dairy manure, and 40% tomato residues. Thus, the extra energy input for adding tomato residues for co-digestion could be compensated by the increase of methane yield. Copyright © 2017 Elsevier Ltd. All rights reserved.

Thorium-based Molten Salt Reactor (TMSR) project in China

International Nuclear Information System (INIS)

Dai, Zhimin; Liu, Wei

2013-01-01

Making great efforts in development of nuclear energy is one of the long-term-plan in China's energy strategies. The advantages of Thorium-based nuclear energy are: rich resource in nature, less nuclear waste, low toxicity, nuclear non-proliferation and so on. Furthermore, China is a country with abundant thorium, thus it is necessary to develop the Thorium-based Molten Salt Reactor (TMSR) in China. Shanghai Institute of Applied Physics, Chinese Academy of Sciences (SINAP) had designed and constructed the first China's light-water reactor and developed a zero-power thorium-based molten salt reactor successfully in the early 1970s. The applied research project 'thorium molten salt reactor nuclear power system' by SINAP together with several other institutes had been accepted and granted by China government in 2011. The whole project has been divided into three stages: Firstly, built a 2 MW-zero-power high temperature solid molten salt reactor in 2015 and a 2 MW-zero-power high temperature liquid molten salt reactor in 2017. Secondly, in 2020 built a 10 MW high temperature liquid molten salt reactor. Thirdly, on the base of previous work, a 100 MW high temperature molten salt reactor should be achieving in 2030. After more than one years of efforts, a high quality scientific research team has been formed, which is able to design the molten salt reactor, the molten salt loop and related key equipment, the systems of molten salt preparation, purification and the radioactive gas removal. In the past one year, the initial physical design of high temperature molten salt reactor has been completed; the nuclear chemistry and radiation chemical laboratory has been built, a high temperature salt (HTS) loop and radioactive gas removal experiment device system have been successfully developed and constructed. Further, the preliminary study on reactor used carbon-carbon composite material has been investigated. (author)

Hydrolysis-acidogenesis of food waste in solid-liquid-separating continuous stirred tank reactor (SLS-CSTR) for volatile organic acid production.

Science.gov (United States)

Karthikeyan, Obulisamy Parthiba; Selvam, Ammaiyappan; Wong, Jonathan W C

2016-01-01

The use of conventional continuous stirred tank reactor (CSTR) can affect the methane (CH4) recovery in a two-stage anaerobic digestion of food waste (FW) due to carbon short circuiting in the hydrolysis-acidogenesis (Hy-Aci) stage. In this research, we have designed and tested a solid-liquid-separating CSTR (SLS-CSTR) for effective Hy-Aci of FW. The working conditions were pH 6 and 9 (SLS-CSTR-1 and -2, respectively); temperature-37°C; agitation-300rpm; and organic loading rate (OLR)-2gVSL(-1)day(-1). The volatile fatty acids (VFA), enzyme activities and bacterial population (by qPCR) were determined as test parameters. Results showed that the Hy-Aci of FW at pH 9 produced ∼35% excess VFA as compared to that at pH 6, with acetic and butyric acids as major precursors, which correlated with the high enzyme activities and low lactic acid bacteria. The design provided efficient solid-liquid separation there by improved the organic acid yields from FW. Copyright © 2015 Elsevier Ltd. All rights reserved.

Development of a three dimension multi-physics code for molten salt fast reactor

International Nuclear Information System (INIS)

Cheng Maosong; Dai Zhimin

2014-01-01

Molten Salt Reactor (MSR) was selected as one of the six innovative nuclear reactors by the Generation IV International Forum (GIF). The circulating-fuel in the can-type molten salt fast reactor makes the neutronics and thermo-hydraulics of the reactor strongly coupled and different from that of traditional solid-fuel reactors. In the present paper: a new coupling model is presented that physically describes the inherent relations between the neutron flux, the delayed neutron precursor, the heat transfer and the turbulent flow. Based on the model, integrating nuclear data processing, CAD modeling, structured and unstructured mesh technology, data analysis and visualization application, a three dimension steady state simulation code system (MSR3DS) for the can-type molten salt fast reactor is developed and validated. In order to demonstrate the ability of the code, the three dimension distributions of the velocity, the neutron flux, the delayed neutron precursor and the temperature were obtained for the simplified MOlten Salt Advanced Reactor Transmuter (MOSART) using this code. The results indicate that the MSR3DS code can provide a feasible description of multi-physical coupling phenomena in can-type molten salt fast reactor. Furthermore, the code can well predict the flow effect of fuel salt and the transport effect of the turbulent diffusion. (authors)

Revue des aspects hydrodynamiques des réacteurs catalytiques gaz-liquide-solide à lit fixe arrosé Hydrodynamics of Gas-Liquid-Solid Trickle-Bed Reactors: a Critical Review

Directory of Open Access Journals (Sweden)

Attou A.

2006-12-01

élation empirique de la perte de pression et du taux de rétention de liquide ne correspond à une erreur relative moyenne de prédiction acceptable. Seul le modèle phénoménologique étendu d'Al-Dahhan et al. (1998 semble constituer une technique satisfaisante pour la prédiction des deux paramètres hydrodynamiques en régime ruisselant. Néanmoins, son principal inconvénient réside dans la nécessité de déterminer préalablement les deux coefficients du modèle au moyen d'expériences sur des écoulements monophasiques gazeux. De telles expériences restent difficiles à réaliser dans la pratique. Il est cependant regrettable de constater qu'aucune des ces méthodes, qui se distinguent par leurs résultats, n'est basée sur une approche physique des phénomènes hydrodynamiques permettant d'améliorer la connaissance de ces écoulements et de prédire leur comportement en dehors des domaines de conditions expérimentales testées. De ce travail, il ressort la nécessité d'appliquer les outils classiques de la mécanique des fluides diphasique à la description de ces écoulements, en apportant une attention particulière aux phénomènes d'interactions hydrodynamiques auxquelles sont soumises les trois phases du système (gaz, liquide et solide. While it is recognised that the hydrodynamic aspects have a considerable importance in the design and the operation of gas-liquid-solid trickle-bed reactors, the accuracy of the proposed calculation methods remains poor. Most studies in this field have been performed in atmospheric conditions in contrast of industrial reactors operating at quite high pressures. Only recently, some experimental results have been obtained at elevated pressures and correlations have been proposed in these conditions in order to predict the tricking-pulsing transition, the pressure drop and the liquid holdup. The scope of this article is twice. Firstly, the knowledge on the several hydrodynamic aspects of three-phase trickle-bed reactors, including

Reactor design, cold-model experiment and CFD modeling for chemical looping combustion

Energy Technology Data Exchange (ETDEWEB)

Zhang, Shaohua; Ma, Jinchen; Hu, Xintao; Zhao, Haibo; Wang, Baowen; Zheng, Chuguang [Huazhong Univ. of Science and Technology, Wuhan (China). State Key Lab. of Coal Combustion

2013-07-01

Chemical looping combustion (CLC) is an efficient, clean and cheap technology for CO{sub 2} capture, and an interconnected fluidized bed is more appropriate solution for CLC. This paper aims to design a reactor system for CLC, carry out cold-model experiment of the system, and model fuel reactor using commercial CFD software. As for the CLC system, the air reactor (AR) is designed as a fast fluidized bed while the fuel reactor (FR) is a bubbling bed; a cyclone is used for solid separation of the AR exit flow. The AR and FR are separated by two U-type loop seals to remain gas sealed. Considered the chemical kinetics of oxygen carrier, fluid dynamics, pressure balance and mass balance of the system simultaneously, some key design parameters of a CH{sub 4}-fueled and Fe{sub 2}O{sub 3}/Al{sub 2}O{sub 3}-based CLC reactor (thermal power of 50 kWth) are determined, including key geometric parameters (reactor cross-sectional area and reactor height) and operation parameters (bed material quantity, solid circulation rate, apparent gas velocity of each reactor). A cold-model bench having same geometric parameters with its prototype is built up to study the effects of various operation conditions (including gas velocity in the reactors and loop seals, and bed material height, etc.) on the solids circulation rate, gas leakage, and pressure balance. It is witnessed the cold-model system is able to meet special requirements for CLC system such as gas sealing between AR and FR, the circulation rate and particles residence time. Furthermore, the thermal FR reactor with oxygen carrier of Fe{sub 2}O{sub 3}/Al{sub 2}O{sub 3} and fuel of CH{sub 4} is simulated by commercial CFD solver FLUENT. It is found that for the design case the combustion efficiency of CH{sub 4} reaches 88.2%. A few part of methane is unburned due to fast, large bubbles rising through the reactor.

Tasks related to increase of RA reactor exploitation and experimental potential, 03. Crane for handling the vertical experimental channels of the RA reactor - design project

International Nuclear Information System (INIS)

Pavicevic, M.

1963-07-01

Within the work related to improvement of experimental potential of the RA reactor, this document describes the design project of the new crane for handling the vertical experimental channels of the RA reactor, engineering drawings of the crane main elements, mechanical part, design project of the electrical part of the crane and cost estimation

Fusion reactor design and technology program in China

International Nuclear Information System (INIS)

Huang, J.H.

1994-01-01

A fusion-fission hybrid reactor program was launched in 1987. The purpose of development of the hybrid reactor is twofold: to solve the problem of nuclear fuel supply for an expected large-scale development of fission reactor plants, and to maintain the momentum of fusion research. The program is described and the activities and progress of the program are presented. Two conceptual designs of an engineering test reactor with tokamak configuration were developed at the Southwestern Institute of Physics and the Institute of Plasma Physics. The results are a tokamak engineering test breeder (TETB) series design and a fusion-fission hybrid reactor design (SSEHR), characterized by a liquid-Li self-cooled blanket and an He-cooled solid tritium breeder blanket respectively. In parallel with the design studies, relevant technological experiments on a small or medium scale have been supported by this program. These include LHCD, ICRH and pellet injection in the area of plasma engineering; neutronics integral experiments with U, Pu, Fe and Be; various irradiation tests of austenitic and ferritic steels, magnetohydrodynamic (MHD) pressure drop experiments using a liquid metal loop; research into permeation barriers for tritium and hydrogen isotopes; solid tritium breeder tests using an in-situ loop in a fission reactor. All these experiments have proceeded successfully. The second step of this program is now starting. It seems reasonable that most of the research carried out in the first step will continue. ((orig.))

Rotary Bed Reactor for Chemical-Looping Combustion with Carbon Capture. Part 1: Reactor Design and Model Development

KAUST Repository

Zhao, Zhenlong

2013-01-17

Chemical-looping combustion (CLC) is a novel and promising technology for power generation with inherent CO2 capture. Currently, almost all of the research has been focused on developing CLC-based interconnected fluidized-bed reactors. In this two-part series, a new rotary reactor concept for gas-fueled CLC is proposed and analyzed. In part 1, the detailed configuration of the rotary reactor is described. In the reactor, a solid wheel rotates between the fuel and air streams at the reactor inlet and exit. Two purging sectors are used to avoid the mixing between the fuel stream and the air stream. The rotary wheel consists of a large number of channels with copper oxide coated on the inner surface of the channels. The support material is boron nitride, which has high specific heat and thermal conductivity. Gas flows through the reactor at elevated pressure, and it is heated to a high temperature by fuel combustion. Typical design parameters for a thermal capacity of 1 MW have been proposed, and a simplified model is developed to predict the performances of the reactor. The potential drawbacks of the rotary reactor are also discussed. © 2012 American Chemical Society.

Reference values on safety regulation of land disposal of low level radioactive solid waste (the second interim report) and its incorporation into legal regulations

International Nuclear Information System (INIS)

Aoki, Terumi

1994-01-01

Safety regulation of land disposal of low level radioactive solid waste in Japan is based on 'the basic philosophy on the safety regulation of land disposal of low level radioactive solid waste' determined by the Nuclear safety Committee (October 1985). The basic philosophy on the upper limit of radioactivity of disposed wastes was published as the reference values in the interim report (February 1987) and in the second interim report (June 1992). In the second interim report, the upper limits of radioactivity are established for three types of solid radioactive wastes: 1) metals, incombustible or flame resistant wastes generated nuclear reactor facilities and solidified in vessels, 2) large metallic structures generated from decommissioning of reactor facilities and difficult to solidify in vessels, and 3) radioactive concrete waste generated from decommissioning of reactor facilities. The upper limits of radioactivity are presented for C-14, Co-60, Ni-63, Sr-90, Cs-137, alfa-emmitters, Ca-41 (for concrete) and Eu-152 (for concrete). Related laws and regulations in Japan on safe disposal of low level wastes are explained. (T.H.)

Nuclear reactor

International Nuclear Information System (INIS)

Tilliette, Z.

1975-01-01

A description is given of a nuclear reactor and especially a high-temperature reactor in which provision is made within a pressure vessel for a main cavity containing the reactor core and a series of vertical cylindrical pods arranged in spaced relation around the main cavity and each adapted to communicate with the cavity through two collector ducts or headers for the primary fluid which flows downwards through the reactor core. Each pod contains two superposed steam-generator and circulator sets disposed in substantially symmetrical relation on each side of the hot primary-fluid header which conveys the primary fluid from the reactor cavity to the pod, the circulators of both sets being mounted respectively at the bottom and top ends of the pod

Reactor Noise: A study of Neutronic Fluctuations in Low-Power Nuclear Reactors, with Special Emphasis on Accurate Time-Domain Analysis. RCN Report

Energy Technology Data Exchange (ETDEWEB)

Dragt, J. B.

1968-10-15

Nuclear reactors can be considered as devices in which nuclear energy is produced as a result of neutron-induced fission reactions. Reactor physics is a branch of applied physics, and is concerned with the physical aspects of the design and study of nuclear reactors. The motivation is the achievement of configurations, which meet certain requirements regarding safety, reliability, economy, etc. The reactor physical method is to study neutron populations in a reactor. This study has two aspects : - the microscopic aspect: a study of the nuclear processes that take place. This aspect belongs to nuclear physics. Reaction probabilities can be expressed in cross sections,which are assumed to be known for the second part: - the macroscopic aspect, concerned with neutron migration and multiplication. All basic features may be traced back to a knowledge of neutron distribution functions. For most phenomena it is sufficient to study the singulet density, i.e. the mean number of neutrons per unit volume, unit velocity, moving in unit solid angle. For the subject of this thesis this singulet density will appear to be insufficient. The theory for the macroscopic aspect is part of statistical mechanics, and is closely related to other statistical theories, for phenomena like transfer of radiation in stellar atmosphere, penetration of radiation in scattering media, cosmic ray showers, etc.

Reactor Noise: A study of Neutronic Fluctuations in Low-Power Nuclear Reactors, with Special Emphasis on Accurate Time-Domain Analysis. RCN Report

International Nuclear Information System (INIS)

Dragt, J.B.

1968-10-01

Nuclear reactors can be considered as devices in which nuclear energy is produced as a result of neutron-induced fission reactions. Reactor physics is a branch of applied physics, and is concerned with the physical aspects of the design and study of nuclear reactors. The motivation is the achievement of configurations, which meet certain requirements regarding safety, reliability, economy, etc. The reactor physical method is to study neutron populations in a reactor. This study has two aspects : - the microscopic aspect: a study of the nuclear processes that take place. This aspect belongs to nuclear physics. Reaction probabilities can be expressed in cross sections,which are assumed to be known for the second part: - the macroscopic aspect, concerned with neutron migration and multiplication. All basic features may be traced back to a knowledge of neutron distribution functions. For most phenomena it is sufficient to study the singulet density, i.e. the mean number of neutrons per unit volume, unit velocity, moving in unit solid angle. For the subject of this thesis this singulet density will appear to be insufficient. The theory for the macroscopic aspect is part of statistical mechanics, and is closely related to other statistical theories, for phenomena like transfer of radiation in stellar atmosphere, penetration of radiation in scattering media, cosmic ray showers, etc

Relative hazard potential: the basis for definition of safety criteria for fast reactors

International Nuclear Information System (INIS)

Cave, L.; Ilberg, D.

1977-02-01

One of the main safety criteria to be met for larger thermal reactors is that the probability of exceeding the dose limits imposed by 10 CRF 100 should not be greater than 10 per reactor year. The potential hazard presented by a fast reactor could be substantially greater than that due to an LWR. The potential for harm of a reactor system may be judged by the effects which would arise from a severe accident. Several different types of effects may be considered: number of latent fatal cancers; number of deaths due to acute effects; number of thyroid tumors or nodules; extent of property damage; and genetic effects. Analytical methods for comparison are employed in this paper. A second important parameter reviewed in this report is the radio-toxicity attributed to the various isotopes. It was found that the worst conceivable accident to a 1000 MW(e) fast reactor would lead to effects on health greater by an order of magnitude than the worst accident usually considered for an LWR. Therefore, some reconsideration of the need for additional safety criteria for LMFBRs, as a guide to designers in relation to the control of the effects of very severe accidents, is desirable

Heat transfer problems in gas-cooled solid blankets

International Nuclear Information System (INIS)

Fillo, J.A.; Powell, J.R.

1976-01-01

In all fusion reactors using the deuterium-tritium fuel cycle, a large fraction approximately 80 percent of the fusion energy will be released as approximately 14 MeV neutrons which must be slowed down in a relatively thick blanket surrounding the plasma, thereby, converting their kinetic energy to high temperature heat which can be continuously removed by a coolant stream and converted in part to electricity in a conventional power turbine. Because of the primary goal of achieving minimum radioactivity, to date Brookhaven blanket concepts have been restricted to the use of some form of solid lithium, with inert gas-cooling and in some design cases, water-cooling of the shell structure. Aluminum and graphite have been identified as very promising structural materials for fusion blankets, and conceptual designs based on these materials have been made. Depending on the thermal loading on the ''first'' wall which surrounds the plasma as well as blanket design, heat transfer problems may be noticeably different in gas-cooled solid blankets. Approaches to solution of heat removal problems as well as explanation of: (a) the after-heat problems in blankets; (b) tritium breeding in solids; and (c) materials selection for radiation shields relative to the minimum activity blanket efforts at Brookhaven are discussed

Zero drift and solid Earth tide extracted from relative gravimetric data with principal component analysis

OpenAIRE

Hongjuan Yu; Jinyun Guo; Jiulong Li; Dapeng Mu; Qiaoli Kong

2015-01-01

Zero drift and solid Earth tide corrections to static relative gravimetric data cannot be ignored. In this paper, a new principal component analysis (PCA) algorithm is presented to extract the zero drift and the solid Earth tide, as signals, from static relative gravimetric data assuming that the components contained in the relative gravimetric data are uncorrelated. Static relative gravity observations from Aug. 15 to Aug. 23, 2014 are used as statistical variables to separate the signal and...

Solid breeder test blanket module design and analysis

Energy Technology Data Exchange (ETDEWEB)

Ying, A. [University of California Los Angeles, Los Angeles, CA 90095-1597 (United States)]. E-mail: ying@fusion.ucla.edu; Abdou, M. [University of California Los Angeles, Los Angeles, CA 90095-1597 (United States); Calderoni, P. [University of California Los Angeles, Los Angeles, CA 90095-1597 (United States); Sharafat, S. [University of California Los Angeles, Los Angeles, CA 90095-1597 (United States); Youssef, M. [University of California Los Angeles, Los Angeles, CA 90095-1597 (United States); An, Z. [University of California Los Angeles, Los Angeles, CA 90095-1597 (United States); Abou-Sena, A. [University of California Los Angeles, Los Angeles, CA 90095-1597 (United States); Kim, E. [University of California Los Angeles, Los Angeles, CA 90095-1597 (United States); Reyes, S. [LANL, Livermore, CA (United States); Willms, S. [LANL, Los Alamos, NM (United States); Kurtz, R. [PNNL, Richland, WA (United States)

2006-02-15

This paper presents the design and analysis for the US ITER solid breeder blanket test articles. Objectives of solid breeder blanket testing during the first phase of the ITER operation focus on exploration of fusion break-in phenomena and configuration scoping. Specific emphasis is placed on first wall structural response, evaluation of neutronic parameters, assessment of thermomechanical behavior and characterization of tritium release. The tests will be conducted with three unit cell arrays/sub-modules. The development approach includes: (1) design the unit cell/sub-module for low temperature operations and (2) refer to a reactor blanket design and use engineering scaling to reproduce key parameters under ITER wall loading conditions, so that phenomena under investigation can be measured at a reactor-like level.

Contribution to the use of a solid moderator gas reactor, for naval propulsion; Contribution a l'etude d'un reacteur a gaz, a moderateur solide, pour propulsion navale

Energy Technology Data Exchange (ETDEWEB)

Pheline, J.; Gautier, A.

1960-01-04

In this contribution, the authors discuss works performed in France for the development of nuclear propulsion in merchant ships, notably for an oil tanker of 50.000 tons with 17 knot speed, i.e. a 20.000 Hp engine with an energy produced by a 60 MW gas reactor with a solid moderator and comprising 400 channels loaded with uranium oxide enriched ay 2.8 per cent and sheathed with a refractory alloy. The authors discuss the possible materials for the moderator, the heat transfer medium, the sheath, the fuel and the structures, and report technological studies (mechanical tests, irradiation tests) performed to investigate material properties and their behaviour in operation conditions. They report tests performed to investigate core structure characteristics with respect to neutrons. They finally briefly present a prototype.

UCLA program in reactor studies: The ARIES tokamak reactor study

International Nuclear Information System (INIS)

1991-01-01

The ARIES research program is a multi-institutional effort to develop several visions of tokamak reactors with enhanced economic, safety, and environmental features. The aims are to determine the potential economics, safety, and environmental features of a range of possible tokamak reactors, and to identify physics and technology areas with the highest leverage for achieving the best tokamak reactor. Four ARIES visions are currently planned for the ARIES program. The ARIES-1 design is a DT-burning reactor based on ''modest'' extrapolations from the present tokamak physics database and relies on either existing technology or technology for which trends are already in place, often in programs outside fusion. ARIES-2 and ARIES-4 are DT-burning reactors which will employ potential advances in physics. The ARIES-2 and ARIES-4 designs employ the same plasma core but have two distinct fusion power core designs; ARIES-2 utilize the lithium as the coolant and breeder and vanadium alloys as the structural material while ARIES-4 utilizes helium is the coolant, solid tritium breeders, and SiC composite as the structural material. Lastly, the ARIES-3 is a conceptual D- 3 He reactor. During the period Dec. 1, 1990 to Nov. 31, 1991, most of the ARIES activity has been directed toward completing the technical work for the ARIES-3 design and documenting the results and findings. We have also completed the documentation for the ARIES-1 design and presented the results in various meetings and conferences. During the last quarter, we have initiated the scoping phase for ARIES-2 and ARIES-4 designs

Thermal conductivity of fusion solid breeder materials

International Nuclear Information System (INIS)

Liu, Y.Y.; Tam, S.W.

1986-06-01

Several simple and useful formulae for estimating the thermal conductivity of lithium-containing ceramic tritium breeder materials for fusion reactor blankets are given. These formulae account for the effects of irradiation, as well as solid breeder configuration, i.e., monolith or a packed bed. In the latter case, a coated-sphere concept is found more attractive in incorporating beryllia (a neutron multiplier) into the blanket than a random mixture of solid breeder and beryllia spheres

Development of an engineering-scale nuclear test of a solid-breeder fusion-blanket concept

International Nuclear Information System (INIS)

Deis, G.A.; Bohn, T.S.; Hsu, P.Y.; Miller, L.G.; Scott, A.J.; Watts, K.D.; Welch, E.C.

1983-08-01

As part of the Phase I effort on Program Element-II (PE-II) of the Office of Fusion Energy/Argonne National Laboratory First Wall/Blanket/Shield Engineering Technology Program, a study has been performed to develop preconceptual hardware designs and preliminary test program descriptions for two fission-reactor-based tests of a water-cooled, solid-breeder fusion reactor blanket concept. First, a list of potentially acceptable reactor facilities is developed, based on a list of required reactor characteristics. From this set of facilities, two facilities are selected for study: the Oak Ridge Research Reactor (ORR) and the Power Burst Facility (PBF). A test which employs a cylindrical unit cell of a solid-breeder fusion reactor blanket, with pressurized-water cooling is designed for each facility. The test design is adjusted to the particular characteristics of each reactor. These two test designs are then compared on the basis of technical issues and cost. Both tests can satisfy the PE-II mission: blanket thermal hydraulic and thermomechanical issues. In addition, both reactors will produce prototypical tritium production rates and profiles and release characteristics with little or no additional modifications

Organic matter and containment of uranium and fissiogenic isotopes at the Oklo natural reactors

International Nuclear Information System (INIS)

Nagy, B.; Rigali, M.J.; Davis, D.W.; Parnell, J.

1991-01-01

Some of the Precambrian natural fission reactors at Oklo in Gabon contain abundant organic matter, part of which was liquefied at the time of criticality and subsequently converted to a graphitic solid. The liquid organic matter helps to reduce U(VI) to U(IV) from aqueous solutions, resulting in the precipitation of uraninite. It is known that in the prevailing reactor environments, precipitated uraninite grains incorporated fission products. We report here observations which show that these uraninite crystals were held immobile within the re-solidified, graphitic bituminous organics at Oklo thus enhanced radionuclide containment. Uraninite encased in solid graphitic matter in the organic-rich reactor zones lost virtually no fissiogenic lanthanide isotopes. The first major episode of uranium and lead migration was caused by the intrusion of a swarm of adjacent dolerite dykes about 1,100 Myr after the reactors went critical. Our results from Oklo imply that the use of organic, hydrophobic solids such as graphitic bitumen as a means of immobilizing radionuclides in pre-treated nuclear waste warrants further investigation. (author)

The International Science and Technology Center (ISTC) and ISTC projects related to research reactors. Information review

International Nuclear Information System (INIS)

Tocheniy, L.; Rudneva, V.Ya.

1998-01-01

1. ISTC - history, activities, outlook: The ISTC is an intergovernmental organization established by agreement between the Russian Federation, the European Union, Japan, and the United States. Since 1994, Finland, Sweden, Norway, Georgia, Armenia, Belarus, Kazakhstan and the Kyrgyz Republic have acceded to the Agreement and Statute. At present, the Republic of Korea is finishing the process of accession to the ISTC. All work of the ISTC is aimed at the goals defined in the ISTC Agreement: - To give CIS weapons scientists, particularly those who possess knowledge and skills related to weapons of mass destruction and their delivery systems, the opportunities to redirect their talents to peaceful activities; - To contribute to solving national and international technical problems; - To support the transition to market-based economies; - To support basic and applied research; - To help integrate CIS weapons scientists into the international scientific community. The projects may be funded both through governmental funds of the Funding Parties specified for the ISTC, and by organizations, nominated as Funding Partners of the ISTC. According to the ISTC Statute, approved by the appropriate national organizations, funds used within ISTC projects are exempt from CIS taxes. As of March 1998, more than 1500 proposals had been submitted to the Center, of which 541 were approved for funding, for a total value of approximately US dollars 165 million. The number of scientists and engineers participating in the projects is more than 17,000. 2. Projects Related to Research Reactors: There are about 20 funded and as yet non-funded projects related to various problems of research reactors. Many of them address safety issues. Information review of the results and plans of both ongoing projects and as yet non-funded proposals related to research reactors will be presented with the aim assisting international researchers to establish partnerships or collaboration with ISTC projects

Task types and error types involved in the human-related unplanned reactor trip events

International Nuclear Information System (INIS)

Kim, Jae Whan; Park, Jin Kyun

2008-01-01

In this paper, the contribution of task types and error types involved in the human-related unplanned reactor trip events that have occurred between 1986 and 2006 in Korean nuclear power plants are analysed in order to establish a strategy for reducing the human-related unplanned reactor trips. Classification systems for the task types, error modes, and cognitive functions are developed or adopted from the currently available taxonomies, and the relevant information is extracted from the event reports or judged on the basis of an event description. According to the analyses from this study, the contributions of the task types are as follows: corrective maintenance (25.7%), planned maintenance (22.8%), planned operation (19.8%), periodic preventive maintenance (14.9%), response to a transient (9.9%), and design/manufacturing/installation (6.9%). According to the analysis of the error modes, error modes such as control failure (22.2%), wrong object (18.5%), omission (14.8%), wrong action (11.1%), and inadequate (8.3%) take up about 75% of the total unplanned trip events. The analysis of the cognitive functions involved in the events indicated that the planning function had the highest contribution (46.7%) to the human actions leading to unplanned reactor trips. This analysis concludes that in order to significantly reduce human-induced or human-related unplanned reactor trips, an aide system (in support of maintenance personnel) for evaluating possible (negative) impacts of planned actions or erroneous actions as well as an appropriate human error prediction technique, should be developed

Task types and error types involved in the human-related unplanned reactor trip events

Energy Technology Data Exchange (ETDEWEB)

Kim, Jae Whan; Park, Jin Kyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2008-12-15

In this paper, the contribution of task types and error types involved in the human-related unplanned reactor trip events that have occurred between 1986 and 2006 in Korean nuclear power plants are analysed in order to establish a strategy for reducing the human-related unplanned reactor trips. Classification systems for the task types, error modes, and cognitive functions are developed or adopted from the currently available taxonomies, and the relevant information is extracted from the event reports or judged on the basis of an event description. According to the analyses from this study, the contributions of the task types are as follows: corrective maintenance (25.7%), planned maintenance (22.8%), planned operation (19.8%), periodic preventive maintenance (14.9%), response to a transient (9.9%), and design/manufacturing/installation (6.9%). According to the analysis of the error modes, error modes such as control failure (22.2%), wrong object (18.5%), omission (14.8%), wrong action (11.1%), and inadequate (8.3%) take up about 75% of the total unplanned trip events. The analysis of the cognitive functions involved in the events indicated that the planning function had the highest contribution (46.7%) to the human actions leading to unplanned reactor trips. This analysis concludes that in order to significantly reduce human-induced or human-related unplanned reactor trips, an aide system (in support of maintenance personnel) for evaluating possible (negative) impacts of planned actions or erroneous actions as well as an appropriate human error prediction technique, should be developed.

Reactor protection system. Revision 1

International Nuclear Information System (INIS)

Fairbrother, D.B.; Vincent, D.R.; Lesniak, L.M.

1975-04-01

The reactor protection system-II (RPS-II) designed for use on Babcock and Wilcox 145- and 205-fuel assembly pressurized water reactors is described. In this system, relays in the trip logic have been replaced by solid state devices. A calculating module for the low DNBR, pump status, and offset trip functions has replaced the overpower trip (based on flow and imbalance), the power/RC pump trip, and the variable low pressure trip. Included is a description of the changes from the present Oconee-type reactor protection system (RPS-I), a functional and hardware description of the calculating module, and a discussion of the qualification program conducted to ensure that the degree of protection provided by RPS-II is not less than that provided by previously licensed systems supplied by B and W. (U.S.)

The use of genetic algorithms with niching methods in nuclear reactor related problems

International Nuclear Information System (INIS)

Sacco, Wagner Figueiredo

2000-03-01

Genetic Algorithms (GAs) are biologically motivated adaptive systems which have been used, with good results, in function optimization. However, traditional GAs rapidly push an artificial population toward convergence. That is, all individuals in the population soon become nearly identical. Niching Methods allow genetic algorithms to maintain a population of diverse individuals. GAs that incorporate these methods are capable of locating multiple, optimal solutions within a single population. The purpose of this study is to test existing niching techniques and two methods introduced herein, bearing in mind their eventual application in nuclear reactor related problems, specially the nuclear reactor core reload one, which has multiple solutions. Tests are performed using widely known test functions and their results show that the new methods are quite promising, specially in real world problems like the nuclear reactor core reload. (author)

CFD-DEM simulation of a conceptual gas-cooled fluidized bed nuclear reactor

International Nuclear Information System (INIS)

Almeida, Lucilla C.; Su, Jian

2015-01-01

Several conceptual designs of the fluidized-bed nuclear reactor have been proposed due to its many advantages over conventional nuclear reactors such as PWRs and BWRs. Amongst their characteristics, the enhanced heat transfer and mixing enables a more uniform temperature distribution, reducing the risk of hot-spot and excessive fuel temperature, in addition to resulting in a higher burnup of the fuel. Furthermore, the relationship between the bed height and reactor neutronics turns the coolant flow rate control into a power production mechanism. Moreover, the possibility of removing the fuel by gravity from the movable core in case of a loss-of-cooling accident increases its safety. High-accuracy modeling of particles and coolant flow in fluidized bed reactors is needed to evaluate reliably the thermal-hydraulic efficiency and safety margin. The two-way coupling between solid and fluid can account for high-fidelity solid-solid interaction and reasonable accuracy in fluid calculation and fluid-solid interaction. In the CFD-DEM model, the particles are modeled as a discrete phase, following the DEM approach, whereas the fluid flow is treated as a continuous phase, described by the averaged Navier-Stokes equations on a computational cell scale. In this work, the coupling methodology between Fluent and Rocky is described. The numerical approach was applied to the simulation of a bubbling fluidized bed and the results were compared to experimental data and showed good agreement. (author)

Reactor power measuring device

International Nuclear Information System (INIS)

Izumi, Mikio; Sano, Yuji; Seki, Eiji; Yoshida, Toshifumi; Ito, Toshiaki.

1993-01-01

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.)

Utilization of nuclear research reactors

International Nuclear Information System (INIS)

1980-01-01

prior to the beginning of the course was of particular value. Interesting scientific visits and demonstrations at the Isotope Institute and at the Central Research Institute for Physics (IFKI), both of the Hungarian Academy of Sciences, were also arranged. During the Study Tour at the Central Institute for Nuclear Research in Rossendorf near Dresden, German Democratic Republic, the participants had the opportunity to observe the organization of a 10 MW nuclear reactor where radioisotopes and radiopharmaceuticals are produced on a commercial scale. Lectures were delivered by local scientists on some of their programmes in applied research in solid state physics and material sciences. At the Technical University of Dresden, the group visited the homogeneous solid-moderated zero-power training reactor (AKR), primarily dedicated to nuclear education and training. Studies on different theoretical and experimental aspects of radiation protection (solid state nuclear track and thermoluminescent detectors) are also being carried out. The last day of the Study Tour was devoted to a visit to the College for Advanced Technology at Zittau, where a training reactor with a power of a few watts has been recently installed. (author)

Safeguarding research reactors

International Nuclear Information System (INIS)

Powers, J.A.

1983-03-01

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

Mathematical simulation of hazardous ion retention from radioactive waste in fixed bed reactor

International Nuclear Information System (INIS)

Sohsah, M.A.; Gohneim, M.M.; Othman, S.H.; El-Anadouli, B.E.

2007-01-01

Reactor design for fluid-solid, noncatalytic reaction depends on the prediction of the performance of the reactor kinetically. The most mathematical models used to handle fixed bed reactor in which the solid bed constitute one of the reactants, while a second reactant is in the fluid phase are complex and difficult to handle. A new mathematical model which easier to handle has been developed to describe the system under investigation. The model was examined theoretically and experimentally. A column backed with chelating cloth filter to separate radionuclide form radioactive waste solution is used as a practical application for the model. Comparison of the model predictions with the experimental results gives satisfactory agreement at most of the process stages

Economic assumptions for evaluating reactor-related options for managing plutonium

International Nuclear Information System (INIS)

Rothwell, G.

1996-01-01

This paper discusses the economic assumptions in the U.S. National Academy of Sciences' report, Management and Disposition of Excess Weapons Plutonium: Reactor-Related Options (1995). It reviews the Net Present Value approach for discounting and comparing the costs and benefits of reactor-related options. It argues that because risks associated with the returns to plutonium management are unlikely to be constant over time, it is preferable to use a real risk-free rate to discount cash flows and explicitly describe the probability distributions for costs and benefits, allowing decision makers to determine the risk premium of each option. As a baseline for comparison, it assumes that one economic benefit of changing the current plutonium management system is a reduction in on-going Surveillance and Maintenance (S and M) costs. This reduction in the present value of S and M costs can be compared with the discounted costs of each option. These costs include direct construction costs, indirect costs, operating costs minus revenues, and decontamination and decommissioning expenses. The paper also discusses how to conduct an uncertainty analysis. It finishes by summarizing conclusions and recommendations and discusses how these recommendations might apply to the evaluation of Russian plutonium management options. (author)

Research reactors - an overview

International Nuclear Information System (INIS)

West, C.D.

1997-01-01

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

Dry fermentation of manure with straw in continuous plug flow reactor: Reactor development and process stability at different loading rates.

Science.gov (United States)

Patinvoh, Regina J; Kalantar Mehrjerdi, Adib; Sárvári Horváth, Ilona; Taherzadeh, Mohammad J

2017-01-01

In this work, a plug flow reactor was developed for continuous dry digestion processes and its efficiency was investigated using untreated manure bedded with straw at 22% total solids content. This newly developed reactor worked successfully for 230days at increasing organic loading rates of 2.8, 4.2 and 6gVS/L/d and retention times of 60, 40 and 28days, respectively. Organic loading rates up to 4.2gVS/L/d gave a better process stability, with methane yields up to 0.163LCH 4 /gVS added /d which is 56% of the theoretical yield. Further increase of organic loading rate to 6gVS/L/d caused process instability with lower volatile solid removal efficiency and cellulose degradation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Diamond as a solid state micro-fission chamber for thermal neutron detection at the VR-1 research reactor

International Nuclear Information System (INIS)

Pomorski, Michal; Mer-Calfati, Christine; Foulon, Francois; Sklenka, Lubomir; Rataj, Jan; Bily, Tomas

2015-01-01

Diamond exhibits a combination of properties which makes it attractive for neutron detection in hostile conditions. In the particular case of detection in a nuclear reactor, it is resilient to radiation, exhibits a natural low sensitivity to gamma rays, and its small size (as compared with that of gas ionisation chambers) enables fluency monitoring with a high position resolution. We report here on the use of synthetic CVD diamond as a solid state micro-fission chamber with U-235 converting material for in-core thermal neutron monitoring. Two types of thin diamond detectors were developed for this application. The first type of detector is fabricated using thin diamond membrane obtained by etching low-cost commercially available single crystal CVD intrinsic diamond, so called 'optical grade' material. Starting from a few hundred of micrometre thick samples, the sample is sliced with a laser and then plasma etched down to a few tenths of micrometre. Here we report the result obtained with a 17 μm thick device. The detection surface of this detector is equal to 1 mm 2 . Detectors with surfaces up to 1 cm 2 can be fabricated with this technique. The second type of detector is fabricated by growing successively two thin films of diamond, by the microwave enhanced chemical vapour deposition technique, on HPHT single crystal diamond. A first, a film of boron doped (p+) single crystal diamond, a few microns thick, is deposited. Then a second film of intrinsic diamond with a thickness of a few tens of microns is deposited. This results in a P doped, Intrinsic, Metal structure (PIM) structure in which the intrinsic volume id the active part of the detector. Here we report the results obtained with a 20 μm thick intrinsic whose detection surface is equal to 0.5 mm 2 , with the possibility to enlarge the surface of the detector up to 1 cm 2 . These two types of detector were tested at the VR-1 research reactor at the Czech Technical University in Prague. The

Treatment of pig excreta using an SCFBR anaerobic reactor

Directory of Open Access Journals (Sweden)

Kevin G. Molina T.

1999-01-01

Full Text Available A new anaerobic reactor called the Sludge Central Fixed Bed Reactor (SCFBR was built and evaluated for the treatment of liquid residue from the pig farms. The SCFBR has three main parts. The lower area is for sludge, the middle part consists of a concentrically packed zone and an upper area for the separation of solids, liquids and gases. The 28.51 SCFBR reactor was evaluated over a period of 210 days, using three organic loads of 0.548,0.421 and 1.239 g COD/1 day. Initially, the reactor was fed non-continuously using 10 and 10.7 days Hydraulic Retention Times (HRT. The HRT was later decreased to 3.87 days using continuous feeding. For the three 0.548, 0.421 and 1.239 g COD/1 day organic loads, Chemical Oxygen Demand (COD removal was 68%, 81% and 73% respectively and Volatile Solids (VS removal was 53.5%, 55.8% and 50.1% respectively. The SCFBR performed well, as shown by the removal efficiency and stability obtained. A microphotograph of sludge from the lower zone is presented, showing high Methanosaeta (Methanothrix presence.

International Conference on Fast Reactors and Related Fuel Cycles: Safe Technologies and Sustainable Scenarios (FR13). Presentations

International Nuclear Information System (INIS)

2013-01-01

The conference, which was held from 4 to 7 of March 2013 in Paris, provided a forum to exchange information on national and international programmes, and more generally new developments and experience, in the field of fast reactors and related fuel cycle technologies. A first goal was to identify and discuss strategic and technical options that have been proposed by individual countries or companies. Another goal was to promote the development of fast reactors and related fuel cycle technologies in a safe, proliferation resistant and economic way. A third goal was to identify gaps and key issues that need to be addressed in relation to the industrial deployment of fast reactors with a closed fuel cycle. A fourth goal was to engage young scientists and engineers in this field, in particular with sustainability, innovation, simulation, safety, economics and public acceptance

Solid state fermentation for foods and beverages

NARCIS (Netherlands)

Chen, J.; Zhu, Y.; Nout, M.J.R.; Sarkar, P.K.

2013-01-01

The book systematically describes the production of solid-state fermented food and beverage in terms of the history and development of SSF technology and SSF foods, bio-reactor design, fermentation process, various substrate origins and sustainable development. It emphasizes Oriental traditional

Solid State Division progress report for period ending March 31, 1992

International Nuclear Information System (INIS)

Green, P.H.; Hinton, L.W.

1992-09-01

During this period, the division conducted a broad, interdisciplinary materials research program with emphasis on theoretical solid state physics, superconductivity, neutron scattering, synthesis and characterization of materials, ion beam and laser processing, and the structure of solids and surfaces. The High Flux Isotope Reactor was returned to full operation

Solid State Division progress report for period ending March 31, 1992

Energy Technology Data Exchange (ETDEWEB)

Green, P.H.; Hinton, L.W. (eds.)

1992-09-01

During this period, the division conducted a broad, interdisciplinary materials research program with emphasis on theoretical solid state physics, superconductivity, neutron scattering, synthesis and characterization of materials, ion beam and laser processing, and the structure of solids and surfaces. The High Flux Isotope Reactor was returned to full operation.

Aspects and application of etch-pit technique in the distribution detection of uranium in solids

International Nuclear Information System (INIS)

Sachett, I.A.

1973-01-01

Some aspects related to the use of standard glass microscope slide as solid state track detector are presented, as well as studies of measurement of distribution of uranium in various solids determined by means of this technique. The behavior of the various parameters related to the properties of the detector and the results of their measurements are treated. Results obtained on the determination of distribution of uranium in samples of fuel elements of the 'ARGONAUTA' research reactor of Instituto de Engenharia Nuclear - Rio de Janeiro, are included. The samples were taken from the fuel-cladding interface. Finally, some data on levels of contamination of the laboratory equipment in use by uranium during the course of this work are presented [pt

Sludge granulation in an UASB-moving bed biofilm hybrid reactor for efficient organic matter removal and nitrogen removal in biofilm reactor.

Science.gov (United States)

Chatterjee, Pritha; Ghangrekar, M M; Rao, Surampalli

2018-02-01

A hybrid upflow anaerobic sludge blanket (UASB)-moving bed biofilm (MBB) and rope bed biofilm (RBB) reactor was designed for treatment of sewage. Possibility of enhancing granulation in an UASB reactor using moving media to improve sludge retention was explored while treating low-strength wastewater. The presence of moving media in the top portion of the UASB reactor allowed a high solid retention time even at very short hydraulic retention times and helped in maintaining selection pressure in the sludge bed to promote formation of different sized sludge granules with an average settling velocity of 67 m/h. These granules were also found to contain plenty of extracellular polymeric substance (EPS) such as 58 mg of polysaccharides (PS) per gram of volatile suspended solids (VSS) and protein (PN) content of 37 mg/g VSS. Enriched sludge of nitrogen-removing bacteria forming a porous biofilm on the media in RBB was also observed in a concentration of around 894 g/m 2 . The nitrogen removing sludge also had a high EPS content of around 22 mg PS/g VSS and 28 mg PN/g VSS. This hybrid UASB-MBB-RBB reactor with enhanced anaerobic granular sludge treating both carbonaceous and nitrogenous matter may be a sustainable solution for decentralized sewage treatment.

10 CFR 72.128 - Criteria for spent fuel, high-level radioactive waste, reactor-related greater than Class C waste...

Science.gov (United States)

2010-01-01

... 10 Energy 2 2010-01-01 2010-01-01 false Criteria for spent fuel, high-level radioactive waste, reactor-related greater than Class C waste, and other radioactive waste storage and handling. 72.128... STORAGE OF SPENT NUCLEAR FUEL, HIGH-LEVEL RADIOACTIVE WASTE, AND REACTOR-RELATED GREATER THAN CLASS C...

SEBREZ: an inertial-fusion-reactor concept

International Nuclear Information System (INIS)

Meier, W.R.

1982-01-01

The neutronic aspects of an inertial fusion reactor concept that relies on asymmetrical neutronic effects to enhance the tritium production in the breeding zones have been studied. We find that it is possible to obtain a tritium breeding ratio greater than 1.0 with a chamber configuration in which the breeding zones subtend only a fraction of the total solid angle. This is the origin of the name SEBREZ which stands for SEgregated BREeding Zones. It should be emphasized that this is not a reactor design study; rather this study illustrates certain neutronic effects in the context of a particular reactor concept. An understanding of these effects forms the basis of a design technique which has broader application than just the SEBREZ concept

Variability in properties of grouted Phosphate/Sulfate N-Reactor Waste

International Nuclear Information System (INIS)

Lokken, R.O.; Martin, P.F.C.; Bowen, W.M.; Harty, H.; Treat, R.L.

1987-02-01

A Transportable Grout Facility (TGF) is being constructed at the Hanford site in Washington State to convert various low-level liquid wastes to a grout waste form for onsite disposal. The TGF Project is managed by Rockwell Hanford Operations (Rockwell). Oak Ridge National Laboratory (ORNL) has provided a grout formulation for Phosphate/Sulfate N-Reactor Waste, the first waste stream scheduled for grouting beginning in late 1987. The formulation includes a blend of portland cement, fly ash, attapulgite clay, and an illitic clay. Grout will be produced by mixing the blend with Phosphate/Sulfate N-Reactor Waste. These wastes result from decontamination and ion-exchange regeneration activities at Hanford's N-Reactor. Pacific Northwest Laboratory (PNL) is conducting studies on grouted Phosphate/Sulfate N-Reactor Waste to verify that the grout can be successfully processed and, when hardened, that it will meet all performance and regulatory requirements. As part of these studies, PNL is assessing the variability that may be encountered when processing Phosphate/Sulfate N-Reactor Waste grout. Sources of variability that may affect grout properties include the composition and concentrations of the waste and dry solids, temperature, efficiency of dry solids blending, and dry blend storage time. 13 refs., 20 figs., 9 tabs

Investigation of molten salt fast reactor

International Nuclear Information System (INIS)

Kubota, Kenichi; Konomura, Mamoru

2002-01-01

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

Microbial diversity and dynamics during methane production from municipal solid waste

Energy Technology Data Exchange (ETDEWEB)

Bareither, Christopher A., E-mail: christopher.bareither@colostate.edu [Civil and Environmental Engineering, Colorado State University, Ft. Collins, CO 80532 (United States); Geological Engineering, University of Wisconsin-Madison, Madison, WI 53706 (United States); Wolfe, Georgia L., E-mail: gwolfe@wisc.edu [Bacteriology, University of Wisconsin-Madison, Madison, WI 53706 (United States); McMahon, Katherine D., E-mail: tmcmahon@engr.wisc.edu [Bacteriology, Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI 53706 (United States); Benson, Craig H., E-mail: chbenson@wisc.edu [Civil and Environmental Engineering, Geological Engineering, University of Wisconsin-Madison, Madison, WI 53706 (United States)

2013-10-15

Highlights: ► Similar bacterial communities developed following different start-up operation. ► Total methanogens in leachate during the decelerated methane phase reflected overall methane yield. ► Created correlations between methanogens, methane yield, and available substrate. ► Predominant bacteria identified with syntrophic polysaccharide degraders. ► Hydrogenotrophic methanogens were dominant in the methane generation process. - Abstract: The objectives of this study were to characterize development of bacterial and archaeal populations during biodegradation of municipal solid waste (MSW) and to link specific methanogens to methane generation. Experiments were conducted in three 0.61-m-diameter by 0.90-m-tall laboratory reactors to simulate MSW bioreactor landfills. Pyrosequencing of 16S rRNA genes was used to characterize microbial communities in both leachate and solid waste. Microbial assemblages in effluent leachate were similar between reactors during peak methane generation. Specific groups within the Bacteroidetes and Thermatogae phyla were present in all samples and were particularly abundant during peak methane generation. Microbial communities were not similar in leachate and solid fractions assayed at the end of reactor operation; solid waste contained a more abundant bacterial community of cellulose-degrading organisms (e.g., Firmicutes). Specific methanogen populations were assessed using quantitative polymerase chain reaction. Methanomicrobiales, Methanosarcinaceae, and Methanobacteriales were the predominant methanogens in all reactors, with Methanomicrobiales consistently the most abundant. Methanogen growth phases coincided with accelerated methane production, and cumulative methane yield increased with increasing total methanogen abundance. The difference in methanogen populations and corresponding methane yield is attributed to different initial cellulose and hemicellulose contents of the MSW. Higher initial cellulose and

Microbial diversity and dynamics during methane production from municipal solid waste

International Nuclear Information System (INIS)

Bareither, Christopher A.; Wolfe, Georgia L.; McMahon, Katherine D.; Benson, Craig H.

2013-01-01

Highlights: ► Similar bacterial communities developed following different start-up operation. ► Total methanogens in leachate during the decelerated methane phase reflected overall methane yield. ► Created correlations between methanogens, methane yield, and available substrate. ► Predominant bacteria identified with syntrophic polysaccharide degraders. ► Hydrogenotrophic methanogens were dominant in the methane generation process. - Abstract: The objectives of this study were to characterize development of bacterial and archaeal populations during biodegradation of municipal solid waste (MSW) and to link specific methanogens to methane generation. Experiments were conducted in three 0.61-m-diameter by 0.90-m-tall laboratory reactors to simulate MSW bioreactor landfills. Pyrosequencing of 16S rRNA genes was used to characterize microbial communities in both leachate and solid waste. Microbial assemblages in effluent leachate were similar between reactors during peak methane generation. Specific groups within the Bacteroidetes and Thermatogae phyla were present in all samples and were particularly abundant during peak methane generation. Microbial communities were not similar in leachate and solid fractions assayed at the end of reactor operation; solid waste contained a more abundant bacterial community of cellulose-degrading organisms (e.g., Firmicutes). Specific methanogen populations were assessed using quantitative polymerase chain reaction. Methanomicrobiales, Methanosarcinaceae, and Methanobacteriales were the predominant methanogens in all reactors, with Methanomicrobiales consistently the most abundant. Methanogen growth phases coincided with accelerated methane production, and cumulative methane yield increased with increasing total methanogen abundance. The difference in methanogen populations and corresponding methane yield is attributed to different initial cellulose and hemicellulose contents of the MSW. Higher initial cellulose and

Potential of duplex fuel in prebreeder, breeder, and power reactor designs: tests and analyses (AWBA Development Program)

International Nuclear Information System (INIS)

Chao, T.L.; Brennan, J.J.; Duncombe, E.; Schneider, M.J.; Johnson, R.G.R.

1982-09-01

Dual region fuel pellets, called duplex pellets, are comprised of an outer annular region of relatively high uranium fuel enrichment and a center pellet of fertile material with no enrichment. UO 2 and ThO 2 are the fissile and fertile materials of interest. Both prebreeders and breeders are discussed as are the performance advantages of duplex pellets over solid pellets in these two pressurized water reactor types. Advantages of duplex pellets for commercial reactor fuel rods are also discussed. Both irradiation test data and analytical results are used in comparisons. Manufacturing of duplex fuel is discussed

Reactor siting risk comparisons related to recommendations of NUREG-0625

International Nuclear Information System (INIS)

Barsell, A.W.; Dombek, F.S.; Orvis, D.D.

1980-11-01

This document evaluates how implementing the remote siting recommendations for nuclear reactors (NUREG-0625) made by the Siting Policy Task Force of the US Nuclear Regulatory Commission (NRC) can reduce potential public risk. The document analyzes how population density affects site-specific risk for both light water reactors (LWRs) and high-temperature gas-cooled reactors

Reactor science and technology: operation and control of reactors

International Nuclear Information System (INIS)

Qiu Junlong

1994-01-01

This article is a collection of short reports on reactor operation and research in China in 1991. The operation of and research activities linked with the Heavy Water Research Reactor, Swimming Pool Reactor and Miniature Neutron Source Reactor are briefly surveyed. A number of papers then follow on the developing strategies in Chinese fast breeder reactor technology including the conceptual design of an experimental fast reactor (FFR), theoretical studies of FFR thermo-hydraulics and a design for an immersed sodium flowmeter. Reactor physics studies cover a range of topics including several related to work on zero power reactors. The section on reactor safety analysis is concerned largely with the assessment of established, and the presentation of new, computer codes for use in PWR safety calculations. Experimental and theoretical studies of fuels and reactor materials for FBRs, PWRs, BWRs and fusion reactors are described. A final miscellaneous section covers Mo-Tc isotope production in the swimming pool reactor, convective heat transfer in tubes and diffusion of tritium through plastic/aluminium composite films and Li 2 SiO 3 . (UK)

Technical Meeting on Fast Reactors and Related Fuel Cycle Facilities with Improved Economic Characteristics. Working Material

International Nuclear Information System (INIS)

2013-01-01

In recent years, engineering oriented work, rather than basic research and development (R&D), has led to significant progress in improving the economics of innovative fast reactors and associated fuel cycle facilities, while maintaining and even enhancing the safety features of these systems. Optimization of plant size and layout, more compact designs, reduction of the amount of plant materials and the building volumes, higher operating temperatures to attain higher generating efficiencies, improvement of load factor, extended core lifetimes, high fuel burnup, etc. are good examples of achievements to date that have improved the economics of fast neutron systems. The IAEA, through its Technical Working Group on Fast Reactors (TWG-FR) and Technical Working Group on Nuclear Fuel Cycle Options and Spent Fuel Management (TWG-NFCO), devotes many of its initiatives to encouraging technical cooperation and promoting common research and technology development projects among Member States with fast reactor and advanced fuel cycle development programmes, with the general aim of catalysing and accelerating technology advances in these fields. In particular the theme of fast reactor deployment, scenarios and economics has been largely debated during the recent IAEA International Conference on Fast Reactors and Related Fuel Cycles: Safe Technologies and Sustainable Scenarios, held in Paris in March 2013. Several papers presented at this conference discussed the economics of fast reactors from different national and regional perspectives, including business cases, investment scenarios, funding mechanisms and design options that offer significant capital and energy production cost reductions. This Technical Meeting on Fast Reactors and Related Fuel Cycle Facilities with Improved Economic Characteristics addresses Member States’ expressed need for information exchange in the field, with the aim of identifying the main open issues and launching possible initiatives to help and

Zirconium carbide coating for corium experiments related to water-cooled and sodium-cooled reactors

Energy Technology Data Exchange (ETDEWEB)

Plevacova, K. [CEA, DEN, STRI, LMA, Cadarache, 3108 St. Paul lez Durance (France); Journeau, C., E-mail: christophe.journeau@cea.fr [CEA, DEN, STRI, LMA, Cadarache, 3108 St. Paul lez Durance (France); Piluso, P. [CEA, DEN, STRI, LMA, Cadarache, 3108 St. Paul lez Durance (France); Zhdanov, V.; Baklanov, V. [IAE, National Nuclear Centre, Material Structure Investigation Dept., Krasnoarmeiskaya, 10, Kurchatov City (Kazakhstan); Poirier, J. [CEMHTI, 1D, av. de la Recherche Scientifique, 45071 Orleans Cedex 2 (France)

2011-07-01

Since the TMI and Chernobyl accidents the risk of nuclear severe accident is intensively studied for existing and future reactors. In case of a core melt-down accident in a nuclear reactor, a complex melt, called corium, forms. To be able to perform experiments with prototypic corium materials at high temperature, a coating which resists to different corium melts related to Generation I and II Water Reactors and Generation IV sodium fast reactor was researched in our experimental platforms both in IAE NNC in Kazakhstan and in CEA in France. Zirconium carbide was selected as protective coating for graphite crucibles used in our induction furnaces: VCG-135 and VITI. The method of coating application, called reactive wetting, was developed. Zirconium carbide revealed to resist well to the (U{sub x}, Zr{sub y})O{sub 2-z} water reactor corium. It has also the advantage not to bring new elements to this chemical system. The coating was then tested with sodium fast reactor corium melts containing steel or absorbers. Undesirable interactions were observed between the coating and these materials, leading to the carburization of the corium ingots. Concerning the resistance of the coating to oxide melts without ZrO{sub 2}, the zirconium carbide coating keeps its role of protective barrier with UO{sub 2}-Al{sub 2}O{sub 3} below 2000 deg. C but does not resist to a UO{sub 2}-Eu{sub 2}O{sub 3} mixture.

Feasibility study for fast reactor and related fuel cycle. Preliminary studies in 1998

International Nuclear Information System (INIS)

Hayafune, Hiroki; Enuma, Yasuhiro; Kubota, Kenichi; Yoshida, Masashi; Uno, Osamu; Ishikawa, Hiroyasu; Kobayashi, Jun; Umetsu, Youichiro; Ichimiya, Masakazu

1999-10-01

Prior to the feasibility study for fast reactors (FRs) starting from the 1999 fiscal year, planned in the medium and long-term program of JNC, preliminarily studies were performed on 'FR systems except sodium cooled MOX fueled reactors'. Small scale or module type reactors, heavy metal (Pb or Pb-Bi) cooled reactors, gas cooled reactors, light water cooled reactors, and molten salt reactors were studied on the basis of literature. They were evaluated from the viewpoint of the technical possibility (the structure integrity, earthquake resistance, safety, productivity, operability, maintenance repair, difficulty of the development), the long-term targets (market competitiveness as an energy system, utilization of uranium resources, reduction of radioactive waste, security of the non-proliferation), and developmental risk. As the result, the following concepts should be studied for future commercialized FRs. Small scale and module type reactor: Middle-sized reactor with an excellent economical efficiency. Small power reactor with a multipurpose design concept. Gas cooled reactor: CO2 gas cooled reactor, He gas cooled reactor. Heavy metal cooled reactor: Russian type lead cooled reactor. Light water cooled reactor: Light water cooled high converter reactor and super critical pressure light water cooled reactor. Molten salt reactor: Trichloride molten salt reactor which matches the U-Pu cycle. (author)

Reactor safety method

International Nuclear Information System (INIS)

Vachon, L.J.

1980-01-01

This invention relates to safety means for preventing a gas cooled nuclear reactor from attaining criticality prior to start up in the event the reactor core is immersed in hydrogenous liquid. This is accomplished by coating the inside surface of the reactor coolant channels with a neutral absorbing material that will vaporize at the reactor's operating temperature

Acceleration of solid pellets using a plasma gun

International Nuclear Information System (INIS)

Buller, T.L.; Turnbull, R.J.; Kim, K.

1979-01-01

The use of solid pellets of hydrogen isotopes to refuel thermonuclear fusion reactors based on the tokamak configuration will require that the pellets be accelerated to high velocities. One possible method of acceleration is to interact a fast plasma from a plasma gun with the pellets. In this paper preliminary results are given on the acceleration of solid pellets with a plasma gun. The plasma-gun requirements for successful acceleration to high velocities are discussed

Guideline related to training and re-training of research reactor personnel

International Nuclear Information System (INIS)

1983-01-01

The guideline, which entered into force on 1 July 1983, lays down training and re-training requirements to be met by research reactor personnel in the framework of the Radiation Protection Ordinance of 26 November 1969, the Regulation related to the Licensing of Nuclear Facilities of 21 June 1979, and the Regulation related to Further Education in the Field of Radiation Protection 27 January 1975. It contains the scope of application; the principles and objectives; the minimum requirements relating to technical qualification of plant managers, shift personnel, and responsible radiation protection officers; appointment and certification; the preservation of the technical qualification; and exceptional and transitional regulations

Impact of the volume of gaseous phase in closed reactors on ANC results and modelling

Science.gov (United States)

Drapeau, Clémentine; Delolme, Cécile; Lassabatere, Laurent; Blanc, Denise

2016-04-01

The understanding of the geochemical behavior of polluted solid materials is often challenging and requires huge expenses of time and money. Nevertheless, given the increasing amounts of polluted solid materials and related risks for the environment, it is more and more crucial to understand the leaching of majors and trace metals elements from these matrices. In the designs of methods to quantify pollutant solubilization, the combination of experimental procedures with modeling approaches has recently gained attention. Among usual methods, some rely on the association of ANC and geochemical modeling. ANC experiments - Acid Neutralization Capacity - consists in adding known quantities of acid or base to a mixture of water and contaminated solid materials at a given liquid / solid ratio in closed reactors. Reactors are agitated for 48h and then pH, conductivity, redox potential, carbon, majors and heavy metal solubilized are quantified. However, in most cases, the amounts of matrix and water do not reach the total volume of reactors, leaving some space for air (gaseous phase). Despite this fact, no clear indication is given in standard procedures about the effect of this gaseous phase. Even worse, the gaseous phase is never accounted for when exploiting or modeling ANC data. The gaseous phase may exchange CO2 with the solution, which may, in turn, impact both pH and element release. This study lies within the most general framework for the use of geochemical modeling for the prediction of ANC results for the case of pure phases to real phase assemblages. In this study, we focus on the effect of the gaseous phase on ANC experiments on different mineral phases through geochemical modeling. To do so, we use PHREEQC code to model the evolution of pH and element release (including majors and heavy metals) when several matrices are put in contact with acid or base. We model the following scenarios for the gaseous phase: no gas, contact with the atmosphere (open system

Homogenous reactor, elaborations, not released up to end

International Nuclear Information System (INIS)

Takibayev, Zh.S.

2002-01-01

Nowadays the nuclear power uses mainly water moderated reactors, where water or heavy water works as neutron inhibitor or coolant, and fuel solid state is situated in reactor core discretely as fuel element packed in fuel assembly. Such fuel composition in solid state reactors leads to rise in price of reactor itself and, of course, many other inconveniences. Firstly, burning out depth is limited; secondary, agents absorbed neutrons are accumulated in fission products, i. e. it leads to poisoning slag derive and thirdly, there are too many outside agents in reactor core in the form of fuel elements and different constructional materials. It worsens neutron balance of reactor. There are many other inconveniences. Specialists understand this problem. They are looking for escaping of difficulty proposing to begin a wide-ranging design, for example, of a new generation of homogeneous reactor especially with salt liquid, liquid metal fuel. But this problem nowadays can not be nearly decided. It is clear enough that within at least 50-100 years the existing monopoly will not change its attitude to use of new elaboration, for example, reactor with salt liquid fuel unless a sharp necessity of opening up not only 1-2 % of uranium in the case of reactors on thermal neutrons or nearby 10-20 % for fast reactors as nowadays but effective use of all potential of nuclear fission energy contained in natural uranium and thorium resources will be realized. In the report the scheme of nuclear reactor with liquid metal or salt liquid is shown. Such approach can be in future one of possible variants of problem solution in effective opening up of all uranium-plutonium energy resource of our planet. The scheme shows only possible allocations of the container and the pipeline. Their proportioning is one of main problems of future elaborations. A mutual allocation of the container and pipelines was carried out in such way, that demand to the last ones where less than to the container

Method of producing gaseous products using a downflow reactor

Science.gov (United States)

Cortright, Randy D; Rozmiarek, Robert T; Hornemann, Charles C

2014-09-16

Reactor systems and methods are provided for the catalytic conversion of liquid feedstocks to synthesis gases and other noncondensable gaseous products. The reactor systems include a heat exchange reactor configured to allow the liquid feedstock and gas product to flow concurrently in a downflow direction. The reactor systems and methods are particularly useful for producing hydrogen and light hydrocarbons from biomass-derived oxygenated hydrocarbons using aqueous phase reforming. The generated gases may find used as a fuel source for energy generation via PEM fuel cells, solid-oxide fuel cells, internal combustion engines, or gas turbine gensets, or used in other chemical processes to produce additional products. The gaseous products may also be collected for later use or distribution.

Fuel Development For Gas-Cooled Fast Reactors

Energy Technology Data Exchange (ETDEWEB)

M. K. Meyer

2006-06-01

The Generation IV Gas-cooled Fast Reactor (GFR) concept is proposed to combine the advantages of high-temperature gas-cooled reactors (such as efficient direct conversion with a gas turbine and the potential for application of high-temperature process heat), with the sustainability advantages that are possible with a fast-spectrum reactor. The latter include the ability to fission all transuranics and the potential for breeding. The GFR is part of a consistent set of gas-cooled reactors that includes a medium-term Pebble Bed Modular Reactor (PBMR)-like concept, or concepts based on the Gas Turbine Modular Helium Reactor (GT-MHR), and specialized concepts such as the Very High Temperature Reactor (VHTR), as well as actinide burning concepts [ ]. To achieve the necessary high power density and the ability to retain fission gas at high temperature, the primary fuel concept proposed for testing in the United States is a dispersion coated fuel particles in a ceramic matrix. Alternative fuel concepts considered in the U.S. and internationally include coated particle beds, ceramic clad fuel pins, and novel ceramic ‘honeycomb’ structures. Both mixed carbide and mixed nitride-based solid solutions are considered as fuel phases.

Heterogeneous catalytic materials solid state chemistry, surface chemistry and catalytic behaviour

CERN Document Server

Busca, Guido

2014-01-01

Heterogeneous Catalytic Materials discusses experimental methods and the latest developments in three areas of research: heterogeneous catalysis; surface chemistry; and the chemistry of catalysts. Catalytic materials are those solids that allow the chemical reaction to occur efficiently and cost-effectively. This book provides you with all necessary information to synthesize, characterize, and relate the properties of a catalyst to its behavior, enabling you to select the appropriate catalyst for the process and reactor system. Oxides (used both as catalysts and as supports for cata

Treatment for dismantled radioactive solid waste from the TRIGA Mark-2 and 3

International Nuclear Information System (INIS)

Park, Seung Kook; Jung, Kyung Hwan

1999-06-01

Radioactive wastes are generally classified into 3 type depending on their physical property: liquid, solid and gaseous type. State-of -the art concerning liquid waste treatment has already been published; KAERI/TR-1315/99. Solid wastes classification package and treatment method will be studied to effectively manage them during the practical decommissioning work. All of the spent fuel produced during the operation of the TRIGA Mark-2 and 3 have been transported to the US last year, 1998, according to the spent fuel management strategy set-up by the US government for the non-proliferation of nuclear energy. Solid wastes are mainly all equipment existing inside of the reactors, activated concrete among the bio-shielded concrete, pipes, pimps, resin filter and it's housings, heat-exchangers, liquid waste storage tanks, to radioactive waste storage treatment facilities and so on. Solid wastes are generally low-level. They are classified according to the national regulation and nuclear law and IAEA Safety Standard Series ST-1(1996). Medium level radioactive wastes from reactor structures, mainly stainless steel component from the Rotary Specimen Rack(RSR) will be properly dismantled and stored in a shield container such as TIF(TRIGA Irradiated Fuel) container. While, low-level solid waste will be treated and packed in a ISO container(4m 3 ISO container for example) according to the IAEA recommendation. And combustible solid waste such as cloths, gloves, paper etc. will be packed in a 200 liters drum. This state-of-the art shows a general feature of the solid radioactive waste management which will be produced during the decommissioning of the TRIGA Mark-2 and 3 research reactors. (author). 17 refs., 17 tabs., 2 figs

Sludge accumulation in shallow maturation ponds treating UASB reactor effluent: results after 11 years of operation.

Science.gov (United States)

Possmoser-Nascimento, Thiago Emanuel; Rodrigues, Valéria Antônia Justino; von Sperling, Marcos; Vasel, Jean-Luc

2014-01-01

Polishing ponds are natural systems used for the post-treatment of upflow anaerobic sludge blanket (UASB) effluents. They are designed as maturation ponds and their main goal is the removal of pathogens and nitrogen and an additional removal of residual organic matter from the UASB reactor. This study aimed to evaluate organic matter and suspended solids removal as well as sludge accumulation in two shallow polishing ponds in series treating sanitary effluent from a UASB reactor with a population equivalent of 200 inhabitants in Brazil, operating since 2002. For this evaluation, long-term monitoring of biochemical oxygen demand and total suspended solids and bathymetric surveys have been undertaken. The ponds showed an irregular distribution of total solids mass in the sludge layer of the two ponds, with mean accumulation values of 0.020 m(3) person(-1) year(-1) and 0.004 m(3) person(-1) year(-1) in Ponds 1 and 2, leading to around 40% and 8% of the liquid volume occupied by the sediments after 11 years of operation. The first pond showed better efficiency in relation to organic matter removal, although its contribution was limited, due to algal growth. No simple input-output mass balance of solids can be applied to the ponds due to algal growth in the liquid phase and sludge digestion in the sludge.

An improved heat transfer configuration for a solid-core nuclear thermal rocket engine

International Nuclear Information System (INIS)

Clark, J.S.; Walton, J.T.; Mcguire, M.L.

1992-07-01

Interrupted flow, impingement cooling, and axial power distribution are employed to enhance the heat-transfer configuration of a solid-core nuclear thermal rocket engine. Impingement cooling is introduced to increase the local heat-transfer coefficients between the reactor material and the coolants. Increased fuel loading is used at the inlet end of the reactor to enhance heat-transfer capability where the temperature differences are the greatest. A thermal-hydraulics computer program for an unfueled NERVA reactor core is employed to analyze the proposed configuration with attention given to uniform fuel loading, number of channels through the impingement wafers, fuel-element length, mass-flow rate, and wafer gap. The impingement wafer concept (IWC) is shown to have heat-transfer characteristics that are better than those of the NERVA-derived reactor at 2500 K. The IWC concept is argued to be an effective heat-transfer configuration for solid-core nuclear thermal rocket engines. 11 refs

Flow injection analysis-flame atomic absorption spectrometry system for indirect determination of sulfite after on-line reduction of solid-phase manganese (IV) dioxide reactor.

Science.gov (United States)

Zare-Dorabei, Rouholah; Boroun, Shokoufeh; Noroozifar, Meissam

2018-02-01

A new and simple flow injection method followed by atomic absorption spectrometry was developed for indirect determination of sulfite. The proposed method is based on the oxidation of sulfite to sulphate ion using solid-phase manganese dioxide (30% W/W suspended on silica gel beads) reactor. MnO 2 will be reduced to Mn(II) by sample injection in to the column under acidic carrier stream of HNO 3 (pH 2) with flow rate of 3.5mLmin -1 at room temperature. Absorption measurement of Mn(II) which is proportional to the concentration of sulfite in the sample was carried out by atomic absorption spectrometry. The calibration curve was linear up to 25mgL -1 with a detection limit (DL) of 0.08mgL -1 for 400µL injection sample volume. The presented method is efficient toward sulfite determination in sugar and water samples with a relative standard deviation (RSD) less than 1.2% and a sampling rate of about 60h -1 . Copyright © 2017 Elsevier B.V. All rights reserved.

Tritium dynamics in fusion reactor solid breeder

International Nuclear Information System (INIS)

Violante, V.

1986-01-01

In the field of the NET research progrm, the chemical and diffusive processes involved in solid ceramic breeder materials have been analysed. A mathematical model describing the phenomena has been developed to obtain a quantitative evaluation for a first design approach. The data obtained by means of the above mentioned model are in good agreement with the data obtained by other research groups working in Europe and in United States. The computer codes BLANKET2, MC2, FWBC, have been developed to simulate the phenomena

Hydrothermal Processing of Macroalgal Feedstocks in Continuous-Flow Reactors

Energy Technology Data Exchange (ETDEWEB)

Elliott, Douglas C.; Hart, Todd R.; Neuenschwander, Gary G.; Rotness, Leslie J.; Roesijadi, Guri; Zacher, Alan H.; Magnuson, Jon K.

2014-02-03

Wet macroalgal slurries have been converted into a biocrude by hydrothermal liquefaction (HTL) in a bench-scale continuous-flow reactor system. Carbon conversion to a gravity-separable oil product of 58.8% was accomplished at relatively low temperature (350 °C) in a pressurized (subcritical liquid water) environment (20 MPa) when using feedstock slurries with a 21.7% concentration of dry solids. As opposed to earlier work in batch reactors reported by others, direct oil recovery was achieved without the use of a solvent, and biomass trace mineral components were removed by processing steps so that they did not cause processing difficulties. In addition, catalytic hydrothermal gasification (CHG) was effectively applied for HTL byproduct water cleanup and fuel gas production from water-soluble organics. Conversion of 99.2% of the carbon left in the aqueous phase was demonstrated. Finally, as a result, high conversion of macroalgae to liquid and gas fuel products was found with low levels of residual organic contamination in byproduct water. Both process steps were accomplished in continuous-flow reactor systems such that design data for process scale-up was generated.

A Conceptual Supercritical Water Cooled Reactor Design Using a Cruciform Solid Moderator

Energy Technology Data Exchange (ETDEWEB)

Joo, Hyung Kook; Bae, Kang Mok; Yoo, Jae Woon; Lee, Hyun Chul; Noh, Jae Man; Bae, Yoon Yong

2006-01-15

A Super Critical Water-Cooled Reactor(SCWR) concept proposed by Gen-IV has an advantage of a high thermal efficiency. However, there are some difficulties in neutronic core design for a SCWR due to lower moderator density resulting from the high operating temperature over the pseudo-critical temperature. In this report, the design concepts for the fuel assembly and the core for a SCWR were described as a feasibility study on the SCWR core design. HELIOS lattice code which will be used for group constants generation was verified for the application to the low coolant density condition of a SCWR. The TAF module for a thermal hydraulic feedback in MASTER was modified to consider high pressure and temperature of the supercritical coolant with single-phase fluid. A cruciform ZrH{sub 2} solid moderator was proposed for the SCWR fuel assembly design to compensate the lower coolant density. The axial zoning concept with three different enrichments for a fuel rod was used for the axial power shape control. Gadolinia burnable poison rods were used to reduce excess reactivity. Control rod system was grouped into 6 banks to control the excess reactivity of the core during normal operation. An orifice concept for each assembly was applied to control a coolant flow rate individually. As a result of the neutronic analysis for the equilibrium SCWR core, the maximum linear heat generation rete limit was satisfied and the maximum coolant temperature of the core outlet was {approx}590 .deg. C which is lower than 620 .deg. C of the maximum clad temperature limit.

Adapting Dynamic Mathematical Models to a Pilot Anaerobic Digestion Reactor

Directory of Open Access Journals (Sweden)

F. Haugen, R. Bakke, and B. Lie

2013-04-01

Full Text Available A dynamic model has been adapted to a pilot anaerobic reactor fed diarymanure. Both steady-state data from online sensors and laboratory analysis anddynamic operational data from online sensors are used in the model adaptation.The model is based on material balances, and comprises four state variables,namely biodegradable volatile solids, volatile fatty acids, acid generatingmicrobes (acidogens, and methane generating microbes (methanogens. The modelcan predict the methane gas flow produced in the reactor. The model may beused for optimal reactor design and operation, state-estimation and control.Also, a dynamic model for the reactor temperature based on energy balance ofthe liquid in the reactor is adapted. This model may be used for optimizationand control when energy and economy are taken into account.

Process and technological aspects of municipal solid waste gasification. A review

International Nuclear Information System (INIS)

Arena, Umberto

2012-01-01

Highlights: ► Critical assessment of the main commercially available MSW gasifiers. ► Detailed discussion of the basic features of gasification process. ► Description of configurations of gasification-based waste-to-energy units. ► Environmental performance analysis, on the basis of independent sources data. - Abstract: The paper proposes a critical assessment of municipal solid waste gasification today, starting from basic aspects of the process (process types and steps, operating and performance parameters) and arriving to a comparative analysis of the reactors (fixed bed, fluidized bed, entrained bed, vertical shaft, moving grate furnace, rotary kiln, plasma reactor) as well as of the possible plant configurations (heat gasifier and power gasifier) and the environmental performances of the main commercially available gasifiers for municipal solid wastes. The analysis indicates that gasification is a technically viable option for the solid waste conversion, including residual waste from separate collection of municipal solid waste. It is able to meet existing emission limits and can have a remarkable effect on reduction of landfill disposal option.

Entrained Flow Reactor Study of KCl Capture by Solid Additives

DEFF Research Database (Denmark)

Wang, Guoliang; Jensen, Peter Arendt; Wu, Hao

been proved to be very promising additives and havereceived extensive studies during the past decades. However, mostprevious studies were carried out in fixed-bed reactors where the reaction conditions are obviously different from that in suspension fired boilers.Detailed knowledge on the reaction...

Management of solid wastes during decommissioning of research reactors. Evaluation of gross clearance levels and mathematical simulation of solid waste assay techniques

International Nuclear Information System (INIS)

Gopalakrishnan, R.K.; Sobhan Babu, K.; Sharma, D.N.

2008-01-01

Full text: Decommissioning of nuclear facilities constitute a challenge mainly due to the huge and complex nature of radioactive waste generated during this process. In the context of management and disposal of waste and reuse/recycle of usable materials during decommissioning of reactors, clearance levels for relevant radio nuclides are of vital importance. Radionuclide specific clearance levels are developed by IAEA and such levels allow the facility for free release of materials to the environment without further regulatory consideration. An effort has been made in this paper to establish clearance levels for radionuclides associated with various system and structural components of a research reactor and rather than radionuclide specific clearance levels, these values are derived for gross activity concentration, which is more practical for radioactive waste categorization, disposal and reuse or recycle of usable materials. The first step towards the derivation of clearance levels is the calculation of annual doses relating to unit activity concentration for each nuclide using various enveloping scenarios. After the estimation of doses, the limiting enveloping scenario (the one that gives the highest dose) is identified. The clearance levels are then derived by dividing the reference dose level (10 μSv/y) by the annual dose calculated per unit activity concentration for the limiting enveloping scenario The clearance level for gross beta-gamma activity concentration is then evaluated as the product of the limiting clearance level and the number of radionuclides characterized for the structural components. Simulation studies were also carried out for the design of a monitoring system for estimation of activity concentration of the decommissioned materials, especially rubbles/ concrete, using mathematical models. Conventional solid waste assay techniques would not suffice to the requirement of decommissioning waste categorization since very low level activity

Diamond as a solid state micro-fission chamber for thermal neutron detection at the VR-1 research reactor

Energy Technology Data Exchange (ETDEWEB)

Pomorski, Michal; Mer-Calfati, Christine [CEA-LIST, Diamond Sensors Laboratory, 91191, Gif-sur-Yvette (France); Foulon, Francois [CEA, National Institute for Nuclear Science and Technology, 91191, Gif-sur-Yvette (France); Sklenka, Lubomir; Rataj, Jan; Bily, Tomas [Department of Nuclear Reactors,Faculty of Nuclear Science and Physical Engineering, Czech Technical University, V. Holesovickach 2, 180 00 PRAHA 8 (Czech Republic)

2015-07-01

Diamond exhibits a combination of properties which makes it attractive for neutron detection in hostile conditions. In the particular case of detection in a nuclear reactor, it is resilient to radiation, exhibits a natural low sensitivity to gamma rays, and its small size (as compared with that of gas ionisation chambers) enables fluency monitoring with a high position resolution. We report here on the use of synthetic CVD diamond as a solid state micro-fission chamber with U-235 converting material for in-core thermal neutron monitoring. Two types of thin diamond detectors were developed for this application. The first type of detector is fabricated using thin diamond membrane obtained by etching low-cost commercially available single crystal CVD intrinsic diamond, so called 'optical grade' material. Starting from a few hundred of micrometre thick samples, the sample is sliced with a laser and then plasma etched down to a few tenths of micrometre. Here we report the result obtained with a 17 μm thick device. The detection surface of this detector is equal to 1 mm{sup 2}. Detectors with surfaces up to 1 cm{sup 2} can be fabricated with this technique. The second type of detector is fabricated by growing successively two thin films of diamond, by the microwave enhanced chemical vapour deposition technique, on HPHT single crystal diamond. A first, a film of boron doped (p+) single crystal diamond, a few microns thick, is deposited. Then a second film of intrinsic diamond with a thickness of a few tens of microns is deposited. This results in a P doped, Intrinsic, Metal structure (PIM) structure in which the intrinsic volume id the active part of the detector. Here we report the results obtained with a 20 μm thick intrinsic whose detection surface is equal to 0.5 mm{sup 2}, with the possibility to enlarge the surface of the detector up to 1 cm{sup 2}. These two types of detector were tested at the VR-1 research reactor at the Czech Technical University in

FFTF radioactive solid waste handling and transport

International Nuclear Information System (INIS)

Thomson, J.D.

1982-01-01

The equipment necessary for the disposal of radioactive solid waste from the Fast Flux Test Facility (FFTF) is scheduled to be available for operation in late 1982. The plan for disposal of radioactive waste from FFTF will utilize special waste containers, a reusable Solid Waste Cask (SWC) and a Disposable Solid Waste Cask (DSWC). The SWC will be used to transport the waste from the Reactor Containment Building to a concrete and steel DSWC. The DSWC will then be transported to a burial site on the Hanford Reservation near Richland, Washington. Radioactive solid waste generated during the operation of the FFTF consists of activated test assembly hardware, reflectors, in-core shim assemblies and control rods. This radioactive waste must be cleaned (sodium removed) prior to disposal. This paper provides a description of the solid waste disposal process, and the casks and equipment used for handling and transport

Reactor vessel pressure transient protection for pressurized water reactors

International Nuclear Information System (INIS)

Zech, G.

1978-09-01

During the past few years the NRC has been studying the issue of protection of the reactor pressure vessels at Pressurized Water Reactors (PWRs) from transients when the vessels are at a relatively low temperature. This effort was prompted by concerns related to the safety margins available to vessel damage as a result of such events. Nuclear Reactor Regulation Category A Technical Activity No. A-26 was established to set forth the NRC plan for resolution of the generic aspects of this safety issue. The purpose of the report is to document the completion of this generic technical activity

Hot cell works and related irradiation tests in fission reactor for development of new materials for nuclear application

International Nuclear Information System (INIS)

Shikama, Tatsuo

1999-01-01

Present status of research works in Oarai Branch, Institute for Materials Research, Tohoku University, utilizing Japan Materials Testing Reactor and related hot cells will be described.Topics are mainly related with nuclear materials studies, excluding fissile materials, which is mainly aiming for development of materials for advanced nuclear systems such as a nuclear fusion reactor. Conflict between traditional and routined procedures and new demands will be described and future perspective is discussed. (author)

Global scaling analysis for the pebble bed advanced high temperature reactor

International Nuclear Information System (INIS)

Blandford, E.D.; Peterson, P.F.

2009-01-01

Scaled Integral Effects Test (IET) facilities play a critical role in the design certification process of innovative reactor designs. Best-estimate system analysis codes, which minimize deliberate conservatism, require confirmatory data during the validation process to ensure an acceptable level of accuracy as defined by the regulator. The modular Pebble Bed Advanced High Temperature Reactor (PB-AHTR), with a nominal power output of 900 MWth, is the most recent UC Berkeley design for a liquid fluoride salt cooled, solid fuel reactor. The PB-AHTR takes advantage of technologies developed for gas-cooled high temperature thermal and fast reactors, sodium fast reactors, and molten salt reactors. In this paper, non-dimensional scaling groups and similarity criteria are presented at the global system level for a loss of forced circulation transient, where single-phase natural circulation is the primary mechanism for decay heat removal following a primary pump trip. Due to very large margin to fuel damage temperatures, the peak metal temperature of primary-loop components was identified as the key safety parameter of interest. Fractional Scaling Analysis (FSA) methods were used to quantify the intensity of each transfer process during the transient and subsequently rank them by their relative importance while identifying key sources of distortion between the prototype and model. The results show that the development of a scaling hierarchy at the global system level informs the bottom-up scaling analysis. (author)

Basic researches on thermo-hydraulic non-equilibrium phenomena related to nuclear reactor safety

International Nuclear Information System (INIS)

Sakurai, Akira; Kataoka, Isao; Aritomi, Masanori.

1989-01-01

A review was made of recent developments of fundamental researches on thermo-hydraulic non-equilibrium phenomena related to light water reactor safety, in relation to problems to be solved for the improvement of safety analysis codes. As for the problems related to flow con ditions, fundamental researches on basic conservation equations and constitutive equations for transient two-phase flow were reviewed. Regarding to the problems related to thermal non-equilibrium phenomena, fundamental researches on film boiling in pool and forced convection, transient boiling heat transfer and flow behavior caused by pressure transients were reviewed. (author)

Aging considerations for PWR [pressurized water reactor] control rod drive mechanisms and reactor internals

International Nuclear Information System (INIS)

Ware, A.G.

1988-01-01

This paper describes age-related degradation mechanisms affecting life extension of pressurized water reactor control rod drive mechanisms and reactor internals. The major sources of age-related degradation for control rod drive mechanisms are thermal transients such as plant heatups and cooldowns, latchings and unlatchings, long-term aging effects on electrical insulation, and the high temperature corrosive environment. Flow induced loads, the high-temperature corrosive environment, radiation exposure, and high tensile stresses in bolts all contribute to aging related degradation of reactor internals. Another problem has been wear and fretting of instrument guide tubes. The paper also discusses age-related failures that have occurred to date in pressurized water reactors

Definition of breeding gain for molten salt reactors - 147

International Nuclear Information System (INIS)

Nagy, K.; Kloosterman, J.L.; Lathouwers, D.; Van der Hagen, T.H.J.J.

2010-01-01

The graphite-moderated Molten Salt Reactor (MSR) is a potential breeder reactor using the thorium fuel cycle. The MSR has unique properties due to the possibility of making changes to the salt composition during operation. Most important is the extraction of protactinium, which separates the fissile uranium production into two volumes: the reactor core and the external stockpile. The paper focuses on the definition of breeding gain in such a system. The prospects of using breeding gain expressions defined for solid fuel reactors are investigated and new definitions are given which incorporate the processes occurring in the reactor core and the external stockpile. The difference of the growth rate of the mass of fissile material and breeding gain is pointed out. The new definitions are applied to an optimization study of the graphite-salt lattice of a breeder MSR. (authors)

Some studies related to decommissioning of nuclear reactors

International Nuclear Information System (INIS)

Bergman, C.; Menon, S.

1990-02-01

Decommissioning of large nuclear reactors has not yet taken place in the Nordic countries. Small nuclear installations, however, have been dismantled. This NKA-programme has dealt with some interesting and important factors which have to be analysed before a large scale decommissioning programme starts. Prior to decommissioning, knowledge is required regarding the nuclide inventory in various parts of the reactor. Measurements were performed in regions close to the reactor tank and the biological shield. These experimental data are used to verify theoretical calculations. All radioactive waste generated during decommissioning will have to be tansported to a repository. Studies show that in all the Nordic countries there are adequate transport systems with which decommissioning waste can be transported. Another requirement for orderly decommissioning planning is that sufficient information about the plant and its operation history must be available. It appears that if properly handled and sorted, all such information can be extracted from existing documentation. (authors)

The computerized reactor period measurement system for China fast burst reactor-II

International Nuclear Information System (INIS)

Zhao Wuwen; Jiang Zhiguo

1996-01-01

The article simply introduces the hardware, principle, and software of the computerized reactor period measurement system for China Fast Burst Reactor-II (CFBR-II). It also gives the relation between fission yield and pre-reactivity of CFBR-II reactor system of bared reactor with decoupled-component and system of bared reactor with multiple light-material. The computerized measurement system makes the reactor period measurement into automatical and intelligent and also improves the speed and precision of period data on-line process

Computer measurement system of reactor period for China fast burst reactor-II

International Nuclear Information System (INIS)

Zhao Wuwen; Jiang Zhiguo

1997-01-01

The author simply introduces the hardware, principle, and software of the reactor period computer measure system for China Fast Burst Reactor-II (CFBR-II). It also gives the relation between Fission yield and Pre-reactivity of CFBR-II reactor system of bared reactor with decoupled-component and system of bared reactor with multiple light-material. The computer measure system makes the reactor period measurement into automation and intellectualization and also improves the speed and precision of period data process on-line

Thermal-hydraulic analysis techniques for axisymmetric pebble bed nuclear reactor cores

International Nuclear Information System (INIS)

Stroh, K.R.

1979-03-01

The pebble bed reactor's cylindrical core volume contains a random bed of small, spherical fuel-moderator elements. These graphite spheres, containing a central region of dispersed coated-particle fissile and fertile material, are cooled by high pressure helium flowing through the connected interstitial voids. A mathematical model and numerical solution technique have been developed which allow calculation of macroscopic values of thermal-hydraulic variables in an axisymmetric pebble bed nuclear reactor core. The computer program PEBBLE is based on a mathematical model which treats the bed macroscopically as a generating, conducting porous medium. The steady-state model uses a nonlinear Forchheimer-type relation between the coolant pressure gradient and mass flux, with newly derived coefficients for the linear and quadratic resistance terms. The remaining equations in the model make use of mass continuity, and thermal energy balances for the solid and fluid phases

The High Flux Reactor Petten, present status and prospects

Energy Technology Data Exchange (ETDEWEB)

Ahlf, J [Institute for Advanced Materials, Joint Research Centre, Petten (Netherlands)

1990-05-01

The High Flux Reactor (HFR) in Petten, The Netherlands, is a light water cooled and moderated multipurpose research reactor of the closed-tank in pool type. It is operated with highly enriched Uranium fuel at a power of 45 MW. The reactor is owned by the European Communities and operated under contract by the Dutch ECN. The HFR programme is funded by The Netherlands and Germany, a smaller share comes from the specific programmes of the Joint Research Centre (JRC) and from third party contract work. Since its first criticality in 1961 the reactor has been continuously upgraded by implementing developments in fuel element technology and increasing the power from 20 MW to the present 45 MV. In 1984 the reactor vessel was replaced by a new one with an improved accessibility for experiments. In the following years also other ageing equipment has been replaced (primary heat exchangers, pool heat exchanger, beryllium reflector elements, nuclear and process instrumentation, uninterruptable power supply). Control room upgrading is under preparation. A new safety analysis is near to completion and will form the basis for a renewed license. The reactor is used for nuclear energy related research (structural materials and fuel irradiations for LWR's, HTR's and FBR's, fusion materials irradiations). The beam tubes are used for nuclear physics as well as solid state and materials sciences. Radioisotope production at large scale, processing of gemstones and silicon with neutrons, neutron radiography and activation analysis are actively pursued. A clinical facility for boron neutron capture therapy is being designed at one of the large cross section beam tubes. It is foreseen to operate the reactor at least for a further decade. The exploitation pattern may undergo some changes depending on the requirements of the supporting countries and the JRC programmes. (author)

The High Flux Reactor Petten, present status and prospects

International Nuclear Information System (INIS)

Ahlf, J.

1990-01-01

The High Flux Reactor (HFR) in Petten, The Netherlands, is a light water cooled and moderated multipurpose research reactor of the closed-tank in pool type. It is operated with highly enriched Uranium fuel at a power of 45 MW. The reactor is owned by the European Communities and operated under contract by the Dutch ECN. The HFR programme is funded by The Netherlands and Germany, a smaller share comes from the specific programmes of the Joint Research Centre (JRC) and from third party contract work. Since its first criticality in 1961 the reactor has been continuously upgraded by implementing developments in fuel element technology and increasing the power from 20 MW to the present 45 MV. In 1984 the reactor vessel was replaced by a new one with an improved accessibility for experiments. In the following years also other ageing equipment has been replaced (primary heat exchangers, pool heat exchanger, beryllium reflector elements, nuclear and process instrumentation, uninterruptable power supply). Control room upgrading is under preparation. A new safety analysis is near to completion and will form the basis for a renewed license. The reactor is used for nuclear energy related research (structural materials and fuel irradiations for LWR's, HTR's and FBR's, fusion materials irradiations). The beam tubes are used for nuclear physics as well as solid state and materials sciences. Radioisotope production at large scale, processing of gemstones and silicon with neutrons, neutron radiography and activation analysis are actively pursued. A clinical facility for boron neutron capture therapy is being designed at one of the large cross section beam tubes. It is foreseen to operate the reactor at least for a further decade. The exploitation pattern may undergo some changes depending on the requirements of the supporting countries and the JRC programmes. (author)

Summary of IEA-R1 research a reactor licensing related to its power increase from 2 to 10 MW

International Nuclear Information System (INIS)

1989-04-01

This work is a summary of IEA-R1 research reactor licensing related to its power increase from 2 to 10 MW. It reports also safety requirements, fuel elements, and reactor control modifications inherent to power increase. (A.C.A.S.)

Static seals and their application in water-cooled nuclear reactor systems

International Nuclear Information System (INIS)

Anon.

1976-01-01

Information relative to six types of static seals commonly used in the primary cooling systems of nuclear reactors is compiled. This information includes a description of each type of seal, its material of construction, design features, operating experience, and advantages and disadvantages. The types covered include spiral-wound asbestos-filled gaskets, hollow metallic O-rings, Belleville spring type of gasketed joints, integrated elastomer and metal retainer gaskets, and solid metal gaskets with heavy cross sections. Omega, canopy, and lip seals are discussed briefly, and information on flange design for gasketing is also presented

Advancement in reactor coolant chemistry management programs and related technology development in Taiwan

International Nuclear Information System (INIS)

Huang, C.S.; Lin, Chien C.

2000-01-01

Taiwan Power Company (TPC) has three nuclear power plants in operation with a total capacity of 51 GWe, contributing about 30% of electricity generation in Taiwan. The first two plants, Chinshan (CSNPP) and Kuosheng (KSNPP), are boiling water reactor plants, and the third one, Maanshan (MASNPP), is a pressurized water reactor plant. Each plant has two identical reactors. As many nuclear power plant operators worldwide, TPC is committed to operate the plants efficiently, economically, and safely. TPC has developed and implemented several chemistry improvement programs in recent years to improve the coolant chemistry in order to ( l ) protect structure materials from corrosion, (2) reduce radiation exposures to workers and (3) reduce radwaste production and radiation release to the environment. This paper describes TPC's experience in some water chemistry management, radwaste reduction and radiation exposure control programs. Future programs under planning, including implementation of hydrogen water chemistry (HWC) in BWRs, installation of condensate pre-filters, and development of on-line water chemistry monitoring system, are also be briefly discussed. In addition, some material related research and development programs will also be presented. (author)

Statistical evaluation of design-error related nuclear reactor accidents

International Nuclear Information System (INIS)

Ott, K.O.; Marchaterre, J.F.

1981-01-01

In this paper, general methodology for the statistical evaluation of design-error related accidents is proposed that can be applied to a variety of systems that evolves during the development of large-scale technologies. The evaluation aims at an estimate of the combined ''residual'' frequency of yet unknown types of accidents ''lurking'' in a certain technological system. A special categorization in incidents and accidents is introduced to define the events that should be jointly analyzed. The resulting formalism is applied to the development of U.S. nuclear power reactor technology, considering serious accidents (category 2 events) that involved, in the accident progression, a particular design inadequacy. 9 refs

Upflow anaerobic sludge reactors for the treatment of combined industrial effluent in subtropical conditions: a comparison between UASB and UASF reactors

International Nuclear Information System (INIS)

Yasar, A.; Ahmad, N.; Chaudhry, M.N.; Sarwar, M.; Masood, T.; Yaqub, A.

2005-01-01

The performance of anaerobic biological process is heavily process conditions dependent. In this study, an attempt has been made to investigate the influence of process conditions like temperature, sludge age and hydraulic retention time (HRT) on the efficiency of an upflow anaerobic sludge blanket (UASB) reactor and upflow anaerobic sludge filter (UASF) to treat combined industrial wastewater. Reactors were operated at easing ambient temperatures (38, 30, 20 and 14 deg. C) and correspondingly increasing sludge ages (60, 90, 120 and 150 days). At temperature 38 deg. C and sludge age of 60 days, UASF showed better performance than VASE reactor. This mainly due to the enhanced filtration through well-graded sand filter and fairly good biological activity in UASF. At this stage, lack of sludge granulation in VASE reactor resulted in poor biological activity; hence, relatively poor performance. At temperatures 30 and 20 deg. C with sludge ages of 90 and 120 days, respectively, UASB gave better results than UASF. The reason was rapid biological degradation due to proper sludge granulation and favorable temperature. At temperature 14 deg. C, a substantial decrease in the efficiency of UASB reactor as compared to the UASF was evident. Drop in efficiency was because of inhabitation of methanogenic bacteria and liquidation of sludge granules. These factors mounted to a decrease in biological activity, stoppage as production and an increase in total suspended solids (TSS) in the effluent. The influence of hydraulic retention time (ranging between 3-12 hours at an increment of 3 hours) on the removal efficiency of both UASB and UASF was not significant. At favorable temperature (20 to 30 deg. C) and sludge age (90 to 120 days) UASB reactor appeared to be more efficient than UASF.(author)

Concepts for space nuclear multi-mode reactors

International Nuclear Information System (INIS)

Myrabo, L.; Botts, T.E.; Powell, J.R.

1983-01-01

A number of nuclear multi-mode reactor power plants are conceptualized for use with solid core, fixed particle bed and rotating particle bed reactors. Multi-mode systems generate high peak electrical power in the open cycle mode, with MHD generator or turbogenerator converters and cryogenically stored coolants. Low level stationkeeping power and auxiliary reactor cooling (i.e., for the removal of reactor afterheat) are provided in a closed cycle mode. Depending on reactor design, heat transfer to the low power converters can be accomplished by heat pipes, liquid metal coolants or high pressure gas coolants. Candidate low power conversion cycles include Brayton turbogenerator, Rankine turbogenerator, thermoelectric and thermionic approaches. A methodology is suggested for estimating the system mass of multi-mode nuclear power plants as a function of peak electric power level and required mission run time. The masses of closed cycle nuclear and open cycle chemical power systems are briefly examined to identify the regime of superiority for nuclear multi-mode systems. Key research and technology issues for such power plants are also identified

Development of a computer program for the simulation of one-dimensional fixed- and moving-bed reactors

International Nuclear Information System (INIS)

Hartner, P.

1996-11-01

Chemical reactors with a flow through a bed of solid particles are of great importance in the processing industry. Modern computational tools allow for an improved characterization of the complex facts in such reactors leading to new opportunities of optimizing the reactor operation and environmental effects. This thesis is concerned with the development of the one-dimensional simulation software REASIM. The program covers the effects within a reacting bed and is designed for fixed and moving beds. To describe the reactor the balances for energy, momentum and mass are solved. The drying of the particles, pyrolysis and chemical gas-solid and gas-gas reactions are considered. For the description of the chemical gas-solid reactions a particle model for porous solids is developed. The calculation of mass transfer and of chemical reactions is strictly separated. All parameters necessary for the model can be measured in the laboratory. The model equations form a system of partial differential equations. This system is transformed to a set of ordinary differential equations. It is found that the best discretization method is the method of finite differences with the upwind-scheme for situations where convection is strong. The program has a modular structure making it is easy to replace parts of the program by new, improved modules if they become available. (author)

Thymol Hydrogenation in Bench Scale Trickle Bed Reactor

Czech Academy of Sciences Publication Activity Database

Dudas, J.; Hanika, Jiří; Lepuru, J.; Barkhuysen, M.

2005-01-01

Roč. 19, č. 3 (2005), s. 255-262 ISSN 0352-9568 Institutional research plan: CEZ:AV0Z40720504 Keywords : thymol hydrogenation * trickle bed reactor * gas-liquid-solid reaction Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 0.632, year: 2005

Biodrying process: A sustainable technology for treatment of municipal solid waste with high moisture content.

Science.gov (United States)

Tom, Asha P; Pawels, Renu; Haridas, Ajit

2016-03-01

Municipal solid waste with high moisture content is the major hindrance in the field of waste to energy conversion technologies and here comes the importance of biodrying process. Biodrying is a convective evaporation process, which utilizes the biological heat developed from the aerobic reactions of organic components. The numerous end use possibilities of the output are making the biodrying process versatile, which is possible by achieving the required moisture reduction, volume reduction and bulk density enhancement through the effective utilization of biological heat. In the present case study the detailed research and development of an innovative biodrying reactor has been carried out for the treatment of mixed municipal solid waste with high moisture content. A pilot scale biodrying reactor of capacity 565 cm(3) was designed and set up in the laboratory. The reactor dimensions consisted of an acrylic chamber of 60 cm diameter and 200 cm height, and it was enveloped by an insulation chamber. The insulation chamber was provided to minimise the heat losses through the side walls of the reactor. It simulates the actual condition in scaling up of the reactor, since in bigger scale reactors the heat losses through side walls will be negligible while comparing the volume to surface area ratio. The mixed municipal solid waste with initial moisture content of 61.25% was synthetically prepared in the laboratory and the reactor was fed with 109 kg of this substrate. Aerobic conditions were ensured inside the reactor chamber by providing the air at a constant rate of 40 litre per minute, and the direction of air flow was from the specially designed bottom air chamber to the reactor matrix top. The self heating inside reactor matrix was assumed in the range of 50-60°C during the design stage. Innovative biodrying reactor was found to be efficiently working with the temperature inside the reactor matrix rising to a peak value of 59°C by the fourth day of experiment (the

Characteristics and uses of a 250 kW TRIGA reactor

International Nuclear Information System (INIS)

Dimic, V.

1985-01-01

The 250 kW TRIGA Mark II reactor is a light water reactor with solid fuel elements in which the zirconium hydride moderator is homogeneously distributed between enriched uranium. Therefore the reactor has the large prompt negative temperature coefficient of reactivity, the fuel also has very high retention of radioactive fission products. The reactor core is a cylindrical configuration with an annular graphite reflector. The experimental facilities include a rotary specimen rack, a central incore radiation thimble, a pneumatic transfer system, and pulsing capability. Other experimental facilities include two radial and two tangential beam tubes, a graphite thermal column, and a graphite thermalizing column. At the steady state power of 250 kW the peak flux is 1x10 13 n/cm 2 s in the central test position. In addition, pulsing to about 2000 MW is usually provided giving peak fluxes of about 2x10 16 n/cm 2 sec. All TRIGA reactors produce a core-average thermal neutron flux of about 10 7 n.v per watt. Only with very large accelerators could such a high neutron flux be achieved. In order to give an appreciation for the research conducted at research reactors, the types of research could be summarized as follows: thermal neutron scattering, neutron radiography, neutron and nuclear physics, activation analysis, radiochemistry, biology and medicine, and teaching and training. Typical applied research with a 250 kW reactor has been conducted in medicine in biology, archeology, metallurgy and materials science, engineering and criminology. It is well known that research reactors have been used routinely to produce isotopes for industry and medicine. In some instances, reactors are the preferred method of isotope production. We can conclude that the 250 kW TRIGA research reactor is a useful and wide ranging source of radiation for basic and applied research. The operation cost for this instrument is relatively low. (author)

Krypton retention on solid adsorbents

International Nuclear Information System (INIS)

Monson, P.R. Jr.

1982-01-01

An experimental laboratory program was conducted to develop economical solid adsorbents for the retention of krypton from a dissolver off-gas stream. The study indicates that a solid adsorbent system is feasible and competitive with other developing systems which utilize fluorocarbon absorption nd cryogenic distillation. This technology may have potential applications not only in nuclear fuel reprocessing plants, but also in nuclear reactors and in environmental monitoring. Of the 13 prospective adsorbents evaluated with respect to adsorption capacity and cost, the commercially available hydrogen mordenite was the most cost-effective material at subambient temperatures (-40 0 to -80 0 C). Silver mordenite has a higher capacity for krypton retention, but is 50 times more expensive than hydrogen mordenite

Trends and Developments for Fast Neutron Reactors and Related Fuel Cycles

International Nuclear Information System (INIS)

Carré, Frank

2013-01-01

• FR13 – A unique and dedicated framework to share updates on national programs of Fast Reactor developments, projects of new builds and plans for the future: - Near term projects of sodium and lead-alloy Fast Reactors; - Gen-IV visions of sodium-cooled and alternative types of Fast Neutron Reactors (GFR, LFR…). • FR13 – A special emphasis put on Fast Reactor Safety, Sustainability of nuclear fuel cycle and Young Generation perspective. • FR13 – A catalyst for further collaborations and alliances: - To share visions of goals and advisable options for future Fast Reactors and Nuclear Fuel Cycle; - To share cost of R&D and large demonstrations (safety, security, recycling); - To progress towards harmonized international standards; - To integrate national projects into a consistent international roadmap

Research programs carried out at the TRIGA Mark II reactor Vienna

International Nuclear Information System (INIS)

Bock, H.

1978-01-01

During the period July 1976 to July 1978 approximately 170 papers have been published by staff members of the Atominstitute in scientific journals covering the main research fields which are: radiation physics; nuclear physics; reactor technology; neutron solid state physics; radiochemistry; health physics. In the department of reactor technology research work was is done on in-core instrumentation, failed fuel element detection systems and neutron radiography

Studies on the instrumentation of a beam-tube medium flux reactor

International Nuclear Information System (INIS)

Axmann, A.; Pollet, J.L.; Queudot, J.

1979-01-01

In the years 1977/78, the ad hoc commitee for medium-flux reactor development of the Federal Ministry for Research and Technology developed constructional concepts for a medium-flux reactor to be utilized by beam tube experiments. The HMI has elaborated contributions for discussions of the subject of instrumentation, in particular for experiments in solid state physics. These contributions are contained in the report. (orig./RW) [de

Regulatory analysis for the resolution of Generic Issue 115, enhancement of the reliability of the Westinghouse Solid State Protection System

International Nuclear Information System (INIS)

Basdekas, D.L.

1989-05-01

Generic Issue 115 addresses a concern related to the reliability of the Westinghouse reactor protection system for plants using the Westinghouse Solid State Protection System (SSPS). Several options for improving the reliability of the Westinghouse reactor trip function for these plants and their effect on core damage frequency (CDF) and overall risk were evaluated. This regulatory analysis includes a quantitative assessment of the costs and benefits associated with the various options for enhancing the reliability of the Westinghouse SSPS and provides insights for consideration and industry initiatives. No new regulatory requirements are proposed. 25 refs., 11 tabs

Solid phase transport in series fluidised bed reactors

International Nuclear Information System (INIS)

Hayes, M.R.

1980-01-01

In a multistage counter-current fluidised bed column, fluidised bed material is recycled within each stage and a fraction is continuously withdrawn to the next lower stage at a rate dependent only on the rate of removal of the fluidised bed material from the base of the column. It has a particular application to the ion exchange treatment of liquids containing suspended solids, for example leach solutions from uranium ores. (author)

Determination of Pu isotopic composition and 241Am by high resolution gamma spectrometry on solid samples

International Nuclear Information System (INIS)

Sarkar, Arnab; Paul, Sumana; Aggarwal, Suresh K.; Tomar, Bhupendra S.

2011-08-01

The present report gives a detailed account of the development of non-destructive assay technique using high resolution gamma-ray spectrometry (HRGS) for determination of plutonium (Pu) isotopic composition and the 241 Am content in solid Pu samples. Energy range 120-420 keV was used in this study. The methodology involves in situ relative efficiency calibration during the measurement process itself, to reduce the errors and increase the reliability of the method. Twenty solid Pu samples of power reactor and research reactor grade were analyzed by this method and the results were compared with those obtained by thermal ionization mass spectrometry. The accuracy of the final results depends strongly upon the accuracy of the available nuclear data (decay constant, gamma abundance etc.). MATLAB based programme was written to perform the analysis. A counting time of 4 hour was chosen for achieving good statistics on the results for samples having 100-200 mg of Pu. The attainable accuracy is found to be 0.5-1% for the fissile isotopes ( 239 Pu + 241 Pu) and 5-10% for 241 Am content. (author)

Strategy for nuclear wastes incineration in hybrid reactors

International Nuclear Information System (INIS)

Lelievre, F.

1998-01-01

The transmutation of nuclear wastes in accelerator-driven nuclear reactors offers undeniable advantages. But before going into the detailed study of a particular project, we should (i) examine the possible applications of such systems and (ii) compare the different configurations, in order to guide technological decisions. We propose an approach, answering both concerns, based on the complete description of hybrid reactors. It is possible, with only the transmutation objective and a few technological constraints chosen a posteriori, to determine precisely the essential parameters of such reactors: number of reactors, beam current, size of the core, sub-criticality... The approach also clearly pinpoints the strategic decisions, for which the scientist or engineer is not competent. This global scheme is applied to three distinct nuclear cycles: incineration of solid fuel without recycling, incineration of liquid fuel without recycling and incineration of liquid fuel with on-line recycling; and for two spectra, either thermal or fast. We show that the radiotoxicity reduction with a solid fuel is significant only with a fast spectrum, but the incineration times range from 20 to 30 years. The liquid fuel is appropriate only with on-line recycling, at equilibrium. The gain on the radiotoxicity can be considerable and we describe a number of such systems. The potential of ADS for the transmutation of nuclear wastes is confirmed, but we should continue the description of specific systems obtained through this approach. (author)

Preliminary feasibility study of the heat - pipe ENHS reactor

International Nuclear Information System (INIS)

Fratoni, M.; Kim, L.; Mattafirri, S.; Petroski, R.; Greenspan, E.

2007-01-01

This preliminary study assesses the feasibility of designing an Encapsulated Nuclear Heat Source (ENHS) reactor [1] to have a solid core from which heat is removed by liquid-metal heat pipes (HP). Like the SAFE space nuclear reactor core [2], the HP-ENHS core is comprised of fuel rods and HPs embedded in a solid structure arranged in a hexagonal lattice in a 3:1 ratio. The HPs extend beyond the core length and transfer heat to a secondary coolant that flows by natural circulation. The HP-ENHS reactor is designed to preserve many features of the ENHS reactor including 20-year operation without refueling, very small excess reactivity throughout life, natural circulation cooling, walk-away passive safety, and robust proliferation resistance. The target power level and specific power of the HP-ENHS reactor are those of the reference ENHS reactor [1]. Compared to previous ENHS reactor designs utilizing a lead or lead-bismuth alloy natural circulation cooling system, the HP-ENHS reactor offers a number of possible advantageous features including: (1) significantly enhanced decay heat removal capability; (2) no positive void reactivity coefficients; (3) no direct contact between the fuel clad and coolant, hence, relatively lower wet corrosion of the clad; (4) a core that is more robust for transportation; (5) higher temperature potentially offering higher efficiency and hydrogen production capability. The study focuses on four areas: material compatibility analysis, HP performance analysis, neutronic analysis and thermal-hydraulic analysis. Of four high-temperature structural materials evaluated, Mo TZM alloy is the preferred choice; its upper estimated feasible operating temperature is 1350 K. HP performance is evaluated as a function of working fluid type, operating temperature, wick design and HP diameter and length. Sodium is the preferred working fluid and the HP working temperature is 1300 K. The neutronic analysis found that it is possible to achieve criticality

Evaluation of Pressure Changes in HANARO Reactor Hall after a Reactor Shutdown

International Nuclear Information System (INIS)

Han, Geeyang; Han, Jaesam; Ahn, Gukhoon; Jung, Hoansung

2013-01-01

The major objective of this work is intended to evaluate the characteristics of the thermal behavior regarding how the decay heat will be affected by the reactor hall pressure change and the increase of pool water temperature induced in the primary coolant after a reactor shutdown. The particular reactor pool water temperature at the surface where it is evaporated owing to the decay heat resulting in the local heat transfer rate is related to the pressure change response in the reactor hall associated with the primary cooling system because of the reduction of the heat exchanger to remove the heat. The increase in the pool water temperature is proportional to the heat transfer rate in the reactor pool. Consequently, any limit on the reactor pool water temperature imposes a corresponding limit on the reactor hall pressure. At HANARO, the decay heat after a reactor shutdown is mainly removed by the natural circulation cooling in the reactor pool. This paper is written for the safety feature of the pressure change related leakage rate from the reactor hall. The calculation results show that the increase of pressure in the reactor hall will not cause any serious problems to the safety limits although the reactor hall pressure is slightly increased. Therefore, it was concluded that the pool water temperature increase is not so rapid as to cause the pressure to vary significantly in the reactor hall. Furthermore, the mathematical model developed in this work can be a useful analytical tool for scoping and parametric studies in the area of thermal transient analysis, with its proper representation of the interaction between the temperature and pressure in the reactor hall

On-site releases of noble gases and iodine in the event of core meltdown in a swimming pool reactor

International Nuclear Information System (INIS)

Montaignac, E. de.

1976-10-01

Research aimed at defining a standard model accident for swimming pool type reactors, has led to the adoption to the so-called BORAX accident which involves complete meltdown of the reactor core. This type of accident-an accident related to dimensional problems- is useful for calculations concerning reactor components which have to withstand the mechanical forces resulting from the accident. A study of the radiobiological consequences of this type of accident, involving the entire reactor core, required research to determine as accurately as possible how the iodine, noble gases and solid fission products are distributed between the melted core and the site. The joint document in the annexure served as the basis for discussion at the meeting (BEVS/SESR) on 9th March 1973, at which the SESR set the standard parameter values to be used for estimating fission product distributions on the site. (author)

CR-39 as induced track detector in reactor: irradiation effect

International Nuclear Information System (INIS)

Zylberberg, H.

1989-07-01

A systematic study about reactor's neutrons radiation effect and gamma radiation effect on the properties of CR-39 that are significant for its use as induced fission track detector is showed. The following studies deserved attention: kinetics of the fission track chemical development; efficiency to register and to develop fission track; losses of developable tracks; variation in the number of developable tracks and variation in the visible and ultraviolet radiation spectrum. The dissertation is organized in seven specific chapters: solid state nuclear tracks (SSNT); CR-39 as SSNT; objectives and problems presentation; preparation and characterization of CR-39 as SSNT; gamma irradiation effect on the properties of CR-39 as SSNT; reactor neutron irradiation effect on the properties of CR-39 as SSNT and, results discussions and conclusions. The main work contributions are the use of CR-39 in the determination of fissionable nuclide as thorium and uranium in solid and liquid samples; gamma radiation damage on CR-39 as well as the reactor's neutron damage on CR-39. (B.C.A.) 62 refs, 53 figs, 21 tabs

Response characteristics of self-powered flux detectors in CANDU reactors

International Nuclear Information System (INIS)

Allan, C.J.

1978-05-01

As part of the development of a new flux-detector assembly for future CANDU reactors, the sensitivities of a variety of vanadium, cobalt and platinum self-powered detectors have been determined in a simulated CANDU core installed in the ZED-2 test reactor at CRNL. While the vanadium and cobalt detectors had solid emitters, the platinum detectors were of two types, having either solid platinum emitters, or emitters consisting of a platinum sheath over an Inconel core. Almost all of the signal from the cobalt and vanadium detectors is due to neutron events in the emitters. For these detectors we have measured the total sensitivities per unit length. For the platinum detectors, reactor γ-rays and neutrons both contribute appreciably to the output signal, and in addition to the total sensitivity, we have determined the individual neutron and γ-ray sensitivities for these detectors. It was found that the detector sensitivities depend primarily on emitter diameter and that the observed variations can be fitted by means of power laws. (author)

Artificial neural network based modelling approach for municipal solid waste gasification in a fluidized bed reactor.

Science.gov (United States)

Pandey, Daya Shankar; Das, Saptarshi; Pan, Indranil; Leahy, James J; Kwapinski, Witold

2016-12-01

In this paper, multi-layer feed forward neural networks are used to predict the lower heating value of gas (LHV), lower heating value of gasification products including tars and entrained char (LHV p ) and syngas yield during gasification of municipal solid waste (MSW) during gasification in a fluidized bed reactor. These artificial neural networks (ANNs) with different architectures are trained using the Levenberg-Marquardt (LM) back-propagation algorithm and a cross validation is also performed to ensure that the results generalise to other unseen datasets. A rigorous study is carried out on optimally choosing the number of hidden layers, number of neurons in the hidden layer and activation function in a network using multiple Monte Carlo runs. Nine input and three output parameters are used to train and test various neural network architectures in both multiple output and single output prediction paradigms using the available experimental datasets. The model selection procedure is carried out to ascertain the best network architecture in terms of predictive accuracy. The simulation results show that the ANN based methodology is a viable alternative which can be used to predict the performance of a fluidized bed gasifier. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fission fragment assisted reactor concept for space propulsion: Foil reactor

International Nuclear Information System (INIS)

Wright, S.A.

1991-01-01

The concept is to fabricate a reactor using thin films or foils of uranium, uranium oxide and then to coat them on substrates. These coatings would be made so thin as to allow the escaping fission fragments to directly heat a hydrogen propellant. The idea was studied of direct gas heating and direct gas pumping in a nuclear pumped laser program. Fission fragments were used to pump lasers. In this concept two substrates are placed opposite each other. The internal faces are coated with thin foil of uranium oxide. A few of the advantages of this technology are listed. In general, however, it is felt that if one look at all solid core nuclear thermal rockets or nuclear thermal propulsion methods, one is going to find that they all pretty much look the same. It is felt that this reactor has higher potential reliability. It has low structural operating temperatures, very short burn times, with graceful failure modes, and it has reduced potential for energetic accidents. Going to a design like this would take the NTP community part way to some of the very advanced engine designs, such as the gas core reactor, but with reduced risk because of the much lower temperatures

High-temperature and breeder reactors - economic nuclear reactors of the future

International Nuclear Information System (INIS)

Djalilzadeh, A.M.

1977-01-01

The thesis begins with a review of the theory of nuclear fission and sections on the basic technology of nuclear reactors and the development of the first generation of gas-cooled reactors applied to electricity generation. It then deals in some detail with currently available and suggested types of high temperature reactor and with some related subsidiary issues such as the coupling of different reactor systems and various schemes for combining nuclear reactors with chemical processes (hydrogenation, hydrogen production, etc.), going on to discuss breeder reactors and their application. Further sections deal with questions of cost, comparison of nuclear with coal- and oil-fired stations, system analysis of reactor systems and the effect of nuclear generation on electricity supply. (C.J.O.G.)

Hairy foam: carbon nanofibers on solid foam as catalyst support : synthesis, mass transfer, and reactor modeling

NARCIS (Netherlands)

Wenmakers, P.W.A.M.

2010-01-01

The chemical reactor is at the heart of many chemical processes. The chemical industry strives for the most efficient, most compact, and safest chemical reactor. The efficiency of a chemical reactor is determined by the delicate balance of catalyst performance (i.e. selectivity and activity) and the

Saponification pretreatment and solids recirculation as a new anaerobic process for the treatment of slaughterhouse waste.

Science.gov (United States)

Affes, R; Palatsi, J; Flotats, X; Carrère, H; Steyer, J P; Battimelli, A

2013-03-01

Different configurations of anaerobic process, adapted to the treatment of solid slaughterhouse fatty waste, were proposed and evaluated in this study. The tested configurations are based on the combination of anaerobic digestion with/without waste saponification pretreatment (70 °C during 60 min) and with/without recirculation of the digestate solid fraction (ratio=20% w/w). After an acclimation period of substrate pulses-feeding cycles, the reactors were operated in a semi-continuous feeding mode, increasing organic loading rates along experimental time. The degradation of the raw substrate was shown to be the bottleneck of the whole process, obtaining the best performance and process yields in the reactor equipped with waste pretreatment and solids recirculation. Saponification promoted the emulsification and bioavailability of solid fatty residues, while recirculation of solids minimized the substrate/biomass wash-out and induced microbial adaptation to the treatment of fatty substrates. Copyright © 2013 Elsevier Ltd. All rights reserved.

Apparatus and method for determining solids circulation rate

Science.gov (United States)

Ludlow, J Christopher [Morgantown, WV; Spenik, James L [Morgantown, WV

2012-02-14

The invention relates to a method of determining bed velocity and solids circulation rate in a standpipe experiencing a moving packed bed flow, such as the in the standpipe section of a circulating bed fluidized reactor The method utilizes in-situ measurement of differential pressure over known axial lengths of the standpipe in conjunction with in-situ gas velocity measurement for a novel application of Ergun equations allowing determination of standpipe void fraction and moving packed bed velocity. The method takes advantage of the moving packed bed property of constant void fraction in order to integrate measured parameters into simultaneous solution of Ergun-based equations and conservation of mass equations across multiple sections of the standpipe.

The experimental nuclear reactor: AQUILON; Le reacteur nucleaire experimental: AQUILON

Energy Technology Data Exchange (ETDEWEB)

Girard, Y; Koechlin, J C; Moreau, J M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

'Aquilon' is an experimental reactor specially designed for the neutronic study of heterogeneous multiplying media with solid fuel and liquid moderator. Since this study is in general incompatible with energy production, the power of the reactor has been limited to a minimum so as to be able to obtain a simple and compact structure, easy access, good handling and great flexibility of operation and utilisation. (author) [French] 'Aquilon' est un reacteur experimental specialement concu pour l'etude neutronique de milieux multiplicateurs heterogenes a combustible solide et ralentisseur liquide. Cette etude etant en general incompatible avec la production d'energie, on a limite au minimum la puissance du reacteur pour pouvoir obtenir une structure simple et peu encombrante, un acces facile, une bonne maniabilite et une grande souplesse de fonctionnement et d'utilisation. (auteur)

Recycling of hazardous solid waste material using high-temperature solar process heat

Energy Technology Data Exchange (ETDEWEB)

Schaffner, B.; Meier, A.; Wuillemin, D.; Hoffelner, W.; Steinfeld, A.

2003-03-01

A novel high-temperature solar chemical reactor is proposed for the thermal recycling of hazardous solid waste material using concentrated solar power. A 10 kW solar reactor prototype was designed and tested for the carbothermic reduction of electric arc furnace dusts (EAFD). The reactor was subjected to mean solar flux intensities of 2000 kW/m2 and operated in both batch and continuous mode within the temperature range 1120-1400 K. Extraction of up to 99% and 90% of the Zn originally contained in the EAFD was achieved in the residue for the batch and continuous solar experiments, respectively. The condensed off-gas products consisted mainly of Zn, Pb, and Cl. No ZnO was detected when the O{sub 2} concentration remained below 2 vol.-%. The use of concentrated solar energy as the source of process heat offers the possibility of converting hazardous solid waste material into valuable commodities for processes in closed and sustainable material cycles. (author)

Modeling a Packed Bed Reactor Utilizing the Sabatier Process

Science.gov (United States)

Shah, Malay G.; Meier, Anne J.; Hintze, Paul E.

2017-01-01

A numerical model is being developed using Python which characterizes the conversion and temperature profiles of a packed bed reactor (PBR) that utilizes the Sabatier process; the reaction produces methane and water from carbon dioxide and hydrogen. While the specific kinetics of the Sabatier reaction on the RuAl2O3 catalyst pellets are unknown, an empirical reaction rate equation1 is used for the overall reaction. As this reaction is highly exothermic, proper thermal control is of the utmost importance to ensure maximum conversion and to avoid reactor runaway. It is therefore necessary to determine what wall temperature profile will ensure safe and efficient operation of the reactor. This wall temperature will be maintained by active thermal controls on the outer surface of the reactor. Two cylindrical PBRs are currently being tested experimentally and will be used for validation of the Python model. They are similar in design except one of them is larger and incorporates a preheat loop by feeding the reactant gas through a pipe along the center of the catalyst bed. The further complexity of adding a preheat pipe to the model to mimic the larger reactor is yet to be implemented and validated; preliminary validation is done using the smaller PBR with no reactant preheating. When mapping experimental values of the wall temperature from the smaller PBR into the Python model, a good approximation of the total conversion and temperature profile has been achieved. A separate CFD model incorporates more complex three-dimensional effects by including the solid catalyst pellets within the domain. The goal is to improve the Python model to the point where the results of other reactor geometry can be reasonably predicted relatively quickly when compared to the much more computationally expensive CFD approach. Once a reactor size is narrowed down using the Python approach, CFD will be used to generate a more thorough prediction of the reactors performance.

K-capture by Al-Si based Additives in an Entrained Flow Reactor

DEFF Research Database (Denmark)

Wang, Guoliang; Jensen, Peter Arendt; Wu, Hao

2016-01-01

A water slurry, consisting of KCl and Al-Si based additives (kaolin and coal fly ash) was fed into an entrained flow reactor (EFR) to study the K-capturing reaction of the additives at suspension-fired conditions. Solid products collected from the reactor were analysed with respect to total...... of KCl to K-aluminosilicate decreased. When reaction temperature increased from 1100 °C to 1450 °C, the conversion of KCl does not change significantly, which differs from the trend observed in fixed-bed reactor....

Present status of decommissioning in the Musashi Reactor Facility (4)

International Nuclear Information System (INIS)

Uchiyama, Takafumi; Tanzawa, Tomio; Mitsuhashi, Ishi; Morishima, Kayoko; Matsumoto, Tetsuo

2012-01-01

The decommissioning of the Musashi reactor was decided in 2003. Permanent shutdown of the reactor and stopping the operational functions were conducted in 2004. Transportation of the spent fuels was finished in 2006. After 2007, the system and equipment stopping the functions were stored as installed in the reactor facility as radioactive wastes. After separating nonradioactive wastes such as concretes from radioactive wastes with a contamination test, stopping the functions of liquid waste management facility was performed with newly installed drainage facility for radioisotope use in 2010. Solid waste management facility was also dismantled and removed in the same way as liquid waste management facility in 2011. Radioactive wastes packed in containers were moved and stored in the reactor facility. (T. Tanaka)

Status report of Indonesian research reactors

International Nuclear Information System (INIS)

Arbie, B.; Supadi, S.

1995-01-01

A general description of the three Indonesia research reactors, their irradiation facilities and future prospect are given. The 250 kW Triga Mark II in Bandung has been in operation since 1965 and in 1972 its designed power was increased to 1000 kW. The core grid from the previous 250 kW Triga Mark II was then used by Batan for designing and constructing the Kartini reactor in Yogyakarta. This reactor commenced its operation in 1979. Both Triga reactors have served a wide spectrum of utilization such as for manpower training in nuclear engineering, radiochemistry, isotope production, and beam research in solid state physics. The Triga reactor management in Bandung has a strong cooperation with the Bandung Institute of Technology and the one in Yogyakarta with the Gadjah Mada University which has a Nuclear Engineering Department at its Faculty of Engineering. In 1976 there emerged an idea to have a high flux reactor appropriate for Indonesia's intention to prepare an infrastructure for both nuclear energy and non-energy industry era. Such an idea was then realized with the achievement of the first criticality of the RSG-GAS reactor at the Serpong area. It is now expected that by early 1992 the reactor will reach its full 30 MW power level and by the end of 1992 the irradiation facilities be utilizable fully for future scientific and engineering work. As a part of the national LEU fuel development program a study has been underway since early 1989 to convert the RSG-GAS reactor core from using oxide fuel to using higher loading silicide fuel. (author)

Modeling solid-fuel dispersal during slow loss-of-flow-type transients

International Nuclear Information System (INIS)

DiMelfi, R.J.; Fenske, G.R.

1981-01-01

The dispersal, under certain accident conditions, of solid particles of fast-reactor fuel is examined in this paper. In particular, we explore the possibility that solid-fuel fragmentation and dispersal can be driven by expanding fission gas, during a slow LOF-type accident. The consequences of fragmentation are studied in terms of the size and speed of dispersed particles, and the overall quantity of fuel moved. (orig.)

Measuring device for the spatial neutron density distribution within a nuclear reactor

International Nuclear Information System (INIS)

Fracke, A.; Wachtler, H.

1974-01-01

A solid probe in a pneumatic tube is lead from the core to a measuring device outside the pressure vessel and reversely, in order to measure the local neutron density distribution inside a reactor core. The activiable solid probe is in the form of a steel spiral spring with densely open coils and semi-spherical end pieces. A good curve negotiating characteristic of the measuring probe and defined duration times are secured in the reactor core. Furthermore, the interior of the spiral can be filled with a lubricating medium, e.g. molybdenum sulphite, so that a better sliding of the measuring probe into the tubes of the pneumatic tube is ensured. (DG) [de

Converting a Microwave Oven into a Plasma Reactor: A Review

Directory of Open Access Journals (Sweden)

Victor J. Law

2018-01-01

Full Text Available This paper reviews the use of domestic microwave ovens as plasma reactors for applications ranging from surface cleaning to pyrolysis and chemical synthesis. This review traces the developments from initial reports in the 1980s to today’s converted ovens that are used in proof-of-principle manufacture of carbon nanostructures and batch cleaning of ion implant ceramics. Information sources include the US and Korean patent office, peer-reviewed papers, and web references. It is shown that the microwave oven plasma can induce rapid heterogeneous reaction (solid to gas and liquid to gas/solid plus the much slower plasma-induced solid state reaction (metal oxide to metal nitride. A particular focus of this review is the passive and active nature of wire aerial electrodes, igniters, and thermal/chemical plasma catalyst in the generation of atmospheric plasma. In addition to the development of the microwave oven plasma, a further aspect evaluated is the development of methodologies for calibrating the plasma reactors with respect to microwave leakage, calorimetry, surface temperature, DUV-UV content, and plasma ion densities.

First wall and blanket design for the STARFIRE commercial tokamak power reactor

International Nuclear Information System (INIS)

Morgan, G.D.; Trachsel, C.A.; Cramer, B.A.; Bowers, D.A.; Smith, D.L.

1979-01-01

The first wall and blanket design concepts being evaluated for the STARFIRE commercial tokamak reactor study are presented. The two concepts represent different approaches to the mechanical design of a tritium breeding blanket using the reference materials options. Each concept has a separate ferritic steel first wall cooled by heavy water (D 2 O), and a ferritic steel blanket with solid lithium oxide breeder cooled by helium. A separate helium purge system is used in both concepts to extract tritium. The two concepts are compared and relative advantages and disadvantages for each are discussed

Modernization of reactor instrumentation for research reactors at Trombay

International Nuclear Information System (INIS)

Darbhe, M.D.; Chaudhuri, H.

1989-01-01

The three research reactors at Trombay, viz., Apsara, Cirus and Zerlina were commissioned in 1956, 1960 and 1961 respectively. The nuclear instrumentation designs were based on the vacuum tube technology, which was prevalent during those days. The effect of component obsolescence of critical components like vacuum tubes, magnetic amplifiers and sensitrol meter relays was strongly felt since early 1970s. Also, the failure rates of the units were observed to show an increasing trend due to ageing and lack of good quality indigenous spares. Hence it was proposed to replace the nuclear instrumentation units for the three reactors, with those employing modern, state of the art solid state devices, keeping indigenous content as high as practicable. The work started in 1977 with the preparations of specifications and the project was scheduled to be completed in 1981. The project was divided into two phases. The Phase I comprising of nuclear channels common to all reactors and Phase II consisting exclusively of regulating system units of Cirus. The salient stages of project progress and completion were: (i) Fabrication and testing of final design prototypes was completed by end of 1982. (ii) Commissioning of new units at Apsara was completed in January 1984. (iii) Commissioning of new units at Cirus was completed in September 1984. An account of experience in all these stages and problems encountered is given. (author). 6 figs

Development of a down-flow hanging sponge reactor for the treatment of low strength sewage.

Science.gov (United States)

Yoochatchaval, Wilasinee; Onodera, Takashi; Sumino, Haruhiko; Yamaguchi, Takashi; Mizuochi, Motoyuki; Okadera, Tomohiro; Syutsubo, Kazuaki

2014-01-01

The process performance of a down-flow hanging sponge (DHS) reactor for treating low strength sewage (biochemical oxygen demand (BOD) 20-50 mg/L) was investigated in Bangkok, Thailand. The hydraulic retention time (HRT) was set at 4 h during the start-up period and was reduced to 1.5 h in a stepwise manner. Throughout the 300-day operational period, the DHS reactor shows high performance with respect to the removal of total suspended solid (>90% total suspended solid removal efficiency). No clogging of sponge media was observed in response to the self-digestion phenomena of the biofilm. At a HRT of 1.5 h, the BOD removal efficiency was sufficiently high (about 85%). The pathogen Escherichia coli and other coliform bacteria were removed almost completely as well (removal was 99.4% and 98.1%, respectively). Regarding the retained sludge activity measurement, the nitrite oxidation rate was higher than the ammonium oxidation rate (0.031 and 0.022 gram of nitrogen per gram of volatile suspended solids per day, respectively). In the 300 days of operation, the amount of excess sludge production was negligible. Thus, no sludge treatment system is required. Introduction of the DHS system in developing countries is recommended because this system requires a relatively small area, and has low electricity consumption and operation costs.

Feasible reactor power cutback logic development for an integral reactor

International Nuclear Information System (INIS)

Han, Soon-Kyoo; Lee, Chung-Chan; Choi, Suhn; Kang, Han-Ok

2013-01-01

Major features of integral reactors that have been developed around the world recently are simplified operating systems and passive safety systems. Even though highly simplified control system and very reliable components are utilized in the integral reactor, the possibility of major component malfunction cannot be ruled out. So, feasible reactor power cutback logic is required to cope with the malfunction of components without inducing reactor trip. Simplified reactor power cutback logic has been developed on the basis of the real component data and operational parameters of plant in this study. Due to the relatively high rod worth of the integral reactor the control rod assembly drop method which had been adapted for large nuclear power plants was not desirable for reactor power cutback of the integral reactor. Instead another method, the control rod assembly control logic of reactor regulating system controls the control rod assembly movements, was chosen as an alternative. Sensitivity analyses and feasibility evaluations were performed for the selected method by varying the control rod assembly driving speed. In the results, sensitivity study showed that the performance goal of reactor power cutback system could be achieved with the limited range of control rod assembly driving speed. (orig.)

L-Reactor 186-basin cleaning alternatives

International Nuclear Information System (INIS)

Turcotte, M.D.S.

1983-01-01

Operation of L Reactor will necessitate annual cleaning of the L Area 186 basins. Alternatives are presented for sediment discharge due to 186-basin cleaning activities as a basis for choosing the optimal cleaning method. Current cleaning activities (i.e. removal of accumulated sediments) for the P, C and K-Area 186 basins result in suspended solids concentrations in the effluent waters above the NPDES limits, requiring an exemption from the NPDES permit for these short-term releases. The objective of mitigating the 186-basin cleaning activities is to decrease the suspended solids concentrations to within permit limits while continuing satisfactory operation of the basins

Municipal Solid Waste Gasification with Solid Oxide Fuel Cells and Stirling Engine

DEFF Research Database (Denmark)

Rokni, Masoud

2014-01-01

Municipal Solid Waste (MSW) can be considered a valid biomass to be used in a power plant. The major advantage is the reduction of pollutants and greenhouse gases emissions not only within large cities but also globally. Another advantage is that by th eir use it is possible to reduce the waste...... studied to optimize the plant efficiency in terms of operating conditions. Compared with modern waste incinerators with heat recovery, the gasification process integrated with SOFC and Stirling engine permits an increase in electricity output up of 50%, which means that the solid waste gasification......, waste is subject to chemical treatments through air or/and steam utilization; the result is a synthesis gas, called “Syngas” which is principally composed of hydrogen and carbon monoxide. Traces of hydrogen sulfide could also be present which can easily be separated in a desulfurization reactor...

The international symposium on 'chemical engineering of gas-liquid-solid catalyst reactions'

Energy Technology Data Exchange (ETDEWEB)

Hammer, H

1978-06-01

A report on the International Symposium on ''Chemical Engineering of Gas-Liquid-Solid Catalyst Reactions'', sponsored by the University of Liege (3/2-3/78), covers papers on the hydrodynamics, modeling and simulation, operating behavior, and chemical kinetics of trickle-bed reactors; scale-up of a trickle-bed reactor for hydrotreating Kuwait vacuum distillate; experimental results obtained in trickle-bed reactors for hydroprocessing atmospheric residua, hydrogenation of methylstyrene, hydrogenation of butanone, and hydrodemetallization of petroleum residua; advantages and disadvantages of various three-phase reactor types (e.g., for the liquid-phase hydrogenation of carbon monoxide to benzene, SNG, or methanol) and hydrodynamics, mass and heat transfer, and modeling of bubble columns with suspended catalysts (slurry reactors), and their applications (e.g., in SNG and fermentation processes).

Performance of a continuously operated flocculent sludge UASB reactor with slaughterhouse wastewater

Energy Technology Data Exchange (ETDEWEB)

Sayed, S.; Zeeuw, W. de

1988-01-01

This investigation was carried out to assess the performance of a continuously operated, one-stage, flocculent sludge upflow anaerobic sludge blanket (UASB) reactor treating slaughterhouse wastewater at a process temperature of 30/sup 0/C. The results indicate that the type of substrate ingredients, coarse suspended solids, colloidal and soluble compounds in the wastewater, affect the performance of the reactor because of different mechanisms involved in their removal and their subsequent conversion into methane. Two different mechanisms are distinguished. An entrapment mechanism prevails for the elimination of coarse suspended solids while an adsorption mechanism is involved in the removal of the colloidal and soluble fractions of the wastewater. The results obtained lead to the conclusion that the system can satisfactorily handle organic space loads up to 5 kg COD m/sup -3/ day/sup -1/ at 30/sup 0/C. The data indicate, however, that continuing heavy accumulation of substrate components in the reactor is detrimental to the stability of the anaerobic treatment process as the accumulation can lead to sludge flotation and consequently to a complete loss of the active biomass from the reactor.

Terrestrial and extraterrestrial superresonators as drivers for an inertial confinement fusion reactor

International Nuclear Information System (INIS)

Seifritz, W.; Vath, W.

1992-01-01

This paper reports on the recirculating power fraction of a laser-driven inertial confinement fusion (ICF) reactor which can be reduced by using laser diodes to pump a neodymium solid-state laser. To overcome the high costs of two-dimensional arrays of laser diodes, two types of superresonators are proposed: a terrestrially based one and an extraterrestrially based one on a geostationary orbit. Both are designed in such a way that a sequence of short laser pulses (10 to 20 ns wide), each with an energy of 5 to 10 MJ and a frequency of 10 Hz, are produced to trigger a deuterium-tritium ICF reactor. The terrestrial superresonator needs a much smaller number of two-dimensional laser diode arrays than a conventionally pumped once-through solid-state laser system, and the extraterrestrial resonator is pumped by means of concentrated solar radiation. In practice, at least an order of magnitude fewer laser diodes and crystalline calcium fluoride gain media are needed to meet the requirements of a laser driver for an ICF reactor. If, finally, a liquid neodymium laser system could be used for an ICF reactor, the cooling of the gain slabs would be facilitated substantially

Tasks related to increase of RA reactor exploitation and experimental potential, 02. Verification of the system for detecting failures of the RA reactor fuel element cladding; Radovi na povecanju eksploatacionih i eksperimentalnih mogucnosti reaktora RA, 02. Provera sistema za detekciju pucanja kosuljice gorivnog elementa reaktora RA

Energy Technology Data Exchange (ETDEWEB)

Pavicevic, M [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Serbia and Montenegro)

1963-07-15

For the purpose of this task it was necessary to analyze the time dependent distribution of fission products in the fuel element and leaks through the cracks in the cladding; to calculate the quantity of solid fission products, volatile fission products and fission gases for the RA reactor; to collect the data for estimating the activity of the short-living isotopes created by neutron irradiation of D{sub 2}O; analyze the number of delayed neutrons in D{sub 2}O. Experiment were needed to estimate the distribution of Xe and Kr in the heavy water in the reactor channel and analyze the activity of D{sub 2}O and helium based on reactor operation data. For the purpose of verifying the efficiency and safety of the existing system for detecting the cracks of the fuel element cladding is presented in this report together with the review of similar systems at a number of reactors in the world.

Aspects of intellectual property related to the TRIGA reactor in Romania

International Nuclear Information System (INIS)

Chirita, Ion

2008-01-01

Full text: A TRIGA - type research reactor has been operating in Pitesti since 1979. In Romania, the first research reactor - of the WWR-C type - has been operating since 1957. Both these reactors have contributed to the formation of well - trained specialists, whose works constitute an important intellectual and industrial property. Institute for Nuclear Research (formerly INT, then INPR) is the holder of several published patents, such as: Procedure for decontamination of water and primary circuits of irradiation devices; Reconditioning of ion exchangers; Nozzle for flow water gaugers; Oscillating electromagnetic pump; Facility for determining nuclear fuel burnup; Portable monitor for contamination measurements; Cable joints with biological protection; Anti-seismic and thermal connection; Automatic facility for nuclear fuel irradiation testing; Method for determining power distribution specific for research rector fuel elements; Tight end-fittings; Cooling damage facility, etc. Many of these have been applied or can be applied to reactors of the TRIGA family or are already installed or under installation to research reactors of other types. (authors)

Sequential UASB and dual media packed-bed reactors for domestic wastewater treatment - experiment and simulation.

Science.gov (United States)

Rodríguez-Gómez, Raúl; Renman, Gunno

2016-01-01

A wastewater treatment system composed of an upflow anaerobic sludge blanket (UASB) reactor followed by a packed-bed reactor (PBR) filled with Sorbulite(®) and Polonite(®) filter material was tested in a laboratory bench-scale experiment. The system was operated for 50 weeks and achieved very efficient total phosphorus (P) removal (99%), 7-day biochemical oxygen demand removal (99%) and pathogenic bacteria reduction (99%). However, total nitrogen was only moderately reduced in the system (40%). A model focusing on simulation of organic material, solids and size of granules was then implemented and validated for the UASB reactor. Good agreement between the simulated and measured results demonstrated the capacity of the model to predict the behaviour of solids and chemical oxygen demand, which is critical for successful P removal and recovery in the PBR.

Reactor Engineering Department annual report

International Nuclear Information System (INIS)

1985-08-01

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)

Reactor Engineering Division annual report

International Nuclear Information System (INIS)

Matsuura, Shojiro; Nakahara, Yasuaki; Takano, Hideki

1982-09-01

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)

End-Member Formulation of Solid Solutions and Reactive Transport

Energy Technology Data Exchange (ETDEWEB)

Lichtner, Peter C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-09-01

A model for incorporating solid solutions into reactive transport equations is presented based on an end-member representation. Reactive transport equations are solved directly for the composition and bulk concentration of the solid solution. Reactions of a solid solution with an aqueous solution are formulated in terms of an overall stoichiometric reaction corresponding to a time-varying composition and exchange reactions, equivalent to reaction end-members. Reaction rates are treated kinetically using a transition state rate law for the overall reaction and a pseudo-kinetic rate law for exchange reactions. The composition of the solid solution at the onset of precipitation is assumed to correspond to the least soluble composition, equivalent to the composition at equilibrium. The stoichiometric saturation determines if the solid solution is super-saturated with respect to the aqueous solution. The method is implemented for a simple prototype batch reactor using Mathematica for a binary solid solution. Finally, the sensitivity of the results on the kinetic rate constant for a binary solid solution is investigated for reaction of an initially stoichiometric solid phase with an undersaturated aqueous solution.

HMI Department of Nuclear Chemistry and Reactor. Scientific report 1984

International Nuclear Information System (INIS)

1985-01-01

The report gives an account of ongoing R and D work in the following fields: 1) Neutron scattering (method development, crystallography); 2) Damage to solids due to radiation (i.a. reactions to failure, atom transport, changes in material properties); 3) Reactor chemistry (solidification products far radioactive wastes; gas/graphite reactions within the first wall of a fusion reactor); 4) Biomedical trace element research (transport and storage of bioelements, trace element analytics); 5) Geochemical reservoir exploration technique (distribution of elements, complexing etc.); 6) Reactor operation, utilization and possible extensions. Furthermore, a survey is given on publications and lectures as well as on correlations with other fields of research. (RB) [de

New treatment centers for radioactive waste from Russian designed VVER-reactors

International Nuclear Information System (INIS)

Chrubasik, A.

1997-01-01

The nuclear power plants using Russian designed VVER-type reactors, were engineered and designed without any wastes treatment facilities. The liquid and solid waste were collected in storage tanks and shelters. After many years of operation, the storage capabilities are exhausted. The treatment of the stored and still generated waste represents a problem of reactor safety and requires a short term solution. NUKEM has been commissioned to design and construct several new treatment centers to remove and process the stored waste. This paper describes the process and lessons learned on the development of this system. The new radioactive waste treatment center (RWTC) includes comprehensive systems to treat both liquid and solid wastes. The process includes: 1) treatment of evaporator concentrates, 2) treatment of ion exchange resins, 3) treatment of solid burnable waste, 4) treatment of liquid burnable waste, 5) treatment of solid decontaminable waste, 6) treatment of solid compactible waste. To treat these waste streams, various separate systems and facilities are needed. Six major facilities are constructed including: 1. A sorting facility with systems for waste segregation. 2. A high-force compactor facility for volume reduction of non-burnable waste. 3. An incinerator facility for destruction of: 1) solid burnable waste, 2) liquid burnable waste, 3) low level radioactive ion exchange resins. 4. A facility for melting of incineration residue. 5. A cementation facility for stabilization of: 1) medium level radioactive ion exchange resins, 2) solid non compactible waste, 3) compacted solid waste. 6. Separation of radionuclides from evaporator concentrates. This presentation will address the facilities, systems, and lessons learned in the development of the new treatment centers. (author)

Removal of radioactive sodium from experimental breeder reactor-II components and conversion to a disposable solid waste: alcohol recovery

International Nuclear Information System (INIS)

Krusl, J.R.; Washburn, R.A.

1985-01-01

Radioactive sodium is removed from Experimental Breeder Reactor-II components by immersing the components in denatured alcohol until the sodium has reacted with the alcohol. The resulting radioactive sodium-alcohol solution must be processed to separate and convert the sodium to a solid waste for disposal. A process was developed and is described that converts radioactive sodium dissolved in alcohol to a dry powdered carbonate waste product and recovers the alcohol for reuse. The sodium-alcohol waste solution, after adjustment for proper sodium and water content, is fed to a wiped-film evaporator operated at 190 0 C and maintained with a CO 2 atmosphere that converts the dissolved sodium to anhydrous Na 2 CO 3 . The end product, about85 to 90 wt% Na 2 CO 3 , is directed into a 208-l (55-gal) drum for disposal. Alcohol distilled during the process is condensed, collected, and dried for immediate reuse. The composition of the alcohol is not altered in the process

Characterization of the solid radioactive waste from Cernavoda NPP

International Nuclear Information System (INIS)

Iordache, M.; Lautaru, V.; Bujoreanu, D.

2005-01-01

During the operation of a nuclear plant significant quantities of radioactive waste result that have a very large diversity. At Cernavoda NPP large amounts of wastes are either non-radioactive wastes or radioactive wastes, each of these being managed completely different from each other. For a CANDU type reactor, the occurrence of radioactive wastes is due to contamination with the following types of radioactive substances: - fission products resulting from nuclear fuel burning; - activated products from materials composing the technological systems; - activated products in process fluids. Radioactive wastes can be in solid, liquid or gas form. At Cernavoda NPP the solid wastes represent about 70% of the waste volume which is produced during plant operation and as a consequence of maintenance and decontamination operations. The most important types of solid wastes that are obtained and then handled, processed (if necessary) and temporarily stored are: solid low-level radioactive wastes (classified as compactible and non-compactible), solid medium radioactive wastes, spent resins, used filters and filter cartridges. The liquid radioactive waste class includes organic liquids (used oil, scintillator liquids and used solvents) and aqueous wastes resulting from process system operating, from decontamination and maintenance operations. Radioactive gas wastes occur subsequently to the fission process inside the fuel elements as well as due to the neutron activation of process fluids in the reactor systems. As result of plant operation, iodine, noble gases, tritium and radioactive particles occur and are passed toward the ventilation stack in a controlled manner so that environmental release of radioactive materials with concentrations exceeding the maximum permissible level could not occur. (authors)

Solid, double-metal cyanide catalysts for synthesis of ...

Indian Academy of Sciences (India)

Sci. Vol. 126, No. 2, March 2014, pp. 499–509. c Indian Academy of Sciences. Solid, double-metal cyanide catalysts for ... drimers, HPs have a highly branched structural design ... geneous catalysts and corrosion of the reactor lin- ... Carbon dioxide is a greenhouse gas. .... polymer product was reprecipitated from the liquid.

Cassava Stillage Treatment by Thermophilic Anaerobic Continuously Stirred Tank Reactor (CSTR)

Science.gov (United States)

Luo, Gang; Xie, Li; Zou, Zhonghai; Zhou, Qi

2010-11-01

This paper assesses the performance of a thermophilic anaerobic Continuously Stirred Tank Reactor (CSTR) in the treatment of cassava stillage under various organic loading rates (OLRs) without suspended solids (SS) separation. The reactor was seeded with mesophilic anaerobic granular sludge, and the OLR increased by increments to 13.80 kg COD/m3/d (HRT 5d) over 80 days. Total COD removal efficiency remained stable at 90%, with biogas production at 18 L/d (60% methane). Increase in the OLR to 19.30 kg COD/m3/d (HRT 3d), however, led to a decrease in TCOD removal efficiency to 79% due to accumulation of suspended solids and incomplete degradation after shortened retention time. Reactor performance subsequently increased after OLR reduction. Alkalinity, VFA and pH levels were not significantly affected by OLR variation, indicating that no additional alkaline or pH adjustment is required. More than half of the SS in the cassava stillage could be digested in the process when HRT was 5 days, which demonstrated the suitability of anaerobic treatment of cassava stillage without SS separation.

Tritium-related materials problems in fusion reactors

International Nuclear Information System (INIS)

Hickman, R.G.

1976-01-01

Pressing materials problems that must be solved before tritium can be used to produce energy economically in fusion reactors are discussed. The following topics are discussed: (1) breeding tritium, (2) recovering bred tritium, (3) containing tritium, (4) fuel recycling, and (5) laser-fusion fueling

A miniature CSTR cascade for continuous flow of reactions containing solids

OpenAIRE

Mo, Yiming; Jensen, Klavs F

2016-01-01

Continuous handling of solids creates challenges for realizing continuous production of pharmaceuticals and fine chemicals. We present a new miniature continuous stirred-tank reactor (CSTR) cascade to handle solid-forming reactions in flow. Single-phase residence time distribution (RTD) measurements of the CSTR cascade reveal nearly ideal CSTR mixing behavior of the individual units. Consistency of experimental and predicted conversions of a Diels–Alder reaction further confirms the CSTR perf...

Engineering aspects of fluidized bed reactor operation applied to lactase treatment of whole whey

Energy Technology Data Exchange (ETDEWEB)

Metzdorf, C; Fauquex, P F; Flaschel, E; Renken, A

1985-01-01

An interesting possibility for the use of lactoserum in human nutrition is the hydrolysis of lactose to glucose and galactose, sugars which exhibit a better digestibility, a higher solubility, and which have a greater sweetening power than lactose. The hydrolysis is catalyzed by an enzyme, the ..beta..-galactosidase which, due to its high price, must be used continuously, preferentially in immobilized form. The enzyme used for these studies has been immobilized on silica gel precoated with chitosan. When whole whey or partially deproteinized whey is treated, a fluidized bed reactor seems to be the most appropriate to circumvent problems with protein adsorption and reactor plugging. However the fluidization of fine particles with a small density difference between the solid and the liquid may give rise to stability problems. In order to prevent unstable operation of the fluidized bed, the reactor has been equipped with special internals. They impose a radial distribution of the liquid and the solid phase and increase the linear velocity required to achieve a given expansion by a factor of five. Besides the resulting high solids content, the back-mixing of the liquid decreases significantly when static mixer-packings are used.

Development of technology for next generation reactor - Development of next generation reactor in Korea -

Energy Technology Data Exchange (ETDEWEB)

Park, Jong Kyun; Chang, Moon Heuy; Hwang, Yung Dong [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); and others

1993-09-01

The project, development of next generation reactor, aims overall related technology development and obtainment of related license in 2001. The development direction is to determine the reactor type and to build up the design concept in 1994. For development trend analysis of foreign next generation reactor, level-1 PSA, fuel cycle analysis and computer code development are performed on System 80+ and AP 600. Especially for design characteristics analysis and volume upgrade of AP 600, nuclear fuel and reactor core design analysis, coolant circuit design analysis, mechanical structure design analysis and safety analysis etc. are performed. (Author).

Fluidized-bed reactors processes and operating conditions

CERN Document Server

Yates, John G

2016-01-01

The fluidized-bed reactor is the centerpiece of industrial fluidization processes. This book focuses on the design and operation of fluidized beds in many different industrial processes, emphasizing the rationale for choosing fluidized beds for each particular process. The book starts with a brief history of fluidization from its inception in the 1940’s. The authors present both the fluid dynamics of gas-solid fluidized beds and the extensive experimental studies of operating systems and they set them in the context of operating processes that use fluid-bed reactors. Chemical engineering students and postdocs as well as practicing engineers will find great interest in this book.

Cleanup Verification Package for the 118-C-1, 105-C Solid Waste Burial Ground

Energy Technology Data Exchange (ETDEWEB)

M. J. Appel and J. M. Capron

2007-07-25

This cleanup verification package documents completion of remedial action for the 118-C-1, 105-C Solid Waste Burial Ground. This waste site was the primary burial ground for general wastes from the operation of the 105-C Reactor and received process tubes, aluminum fuel spacers, control rods, reactor hardware, spent nuclear fuel and soft wastes.

Cleanup Verification Package for the 118-C-1, 105-C Solid Waste Burial Ground

International Nuclear Information System (INIS)

Appel, M.J.; Capron, J.M.

2007-01-01

This cleanup verification package documents completion of remedial action for the 118-C-1, 105-C Solid Waste Burial Ground. This waste site was the primary burial ground for general wastes from the operation of the 105-C Reactor and received process tubes, aluminum fuel spacers, control rods, reactor hardware, spent nuclear fuel and soft wastes

Morphological evolution of copper nanoparticles: Microemulsion reactor system versus batch reactor system

Science.gov (United States)

Xia, Ming; Tang, Zengmin; Kim, Woo-Sik; Yu, Taekyung; Park, Bum Jun

2017-07-01

In the synthesis of nanoparticles, the reaction rate is important to determine the morphology of nanoparticles. We investigated morphology evolution of Cu nanoparticles in this two different reactors, microemulsion reactor and batch reactor. In comparison with the batch reactor system, the enhanced mass and heat transfers in the emulsion system likely led to the relatively short nucleation time and the highly homogeneous environment in the reaction mixture, resulting in suppressing one or two dimensional growth of the nanoparticles. We believe that this work can offer a good model system to quantitatively understand the crystal growth mechanism that depends strongly on the local monomer concentration, the efficiency of heat transfer, and the relative contribution of the counter ions (Br- and Cl-) as capping agents.

Electron beam absorption in solid and in water phantoms: depth scaling and energy-range relations

International Nuclear Information System (INIS)

Grosswendt, B.; Roos, M.

1989-01-01

In electron dosimetry energy parameters are used with values evaluated from ranges in water. The electron ranges in water may be deduced from ranges measured in solid phantoms. Several procedures recommended by national and international organisations differ both in the scaling of the ranges and in the energy-range relations for water. Using the Monte Carlo method the application of different procedures for electron energies below 10 MeV is studied for different phantom materials. It is shown that deviations in the range scaling and in the energy-range relations for water may accumulate to give energy errors of several per cent. In consequence energy-range relations are deduced for several solid phantom materials which enable a single-step energy determination. (author)

Internally Heated Screw Pyrolysis Reactor (IHSPR) heat transfer performance study

Science.gov (United States)

Teo, S. H.; Gan, H. L.; Alias, A.; Gan, L. M.

2018-04-01

1.5 billion end-of-life tyres (ELT) were discarded globally each year and pyrolysis is considered the best solution to convert the ELT into valuable high energy-density products. Among all pyrolysis technologies, screw reactor is favourable. However, conventional screw reactor risks plugging issue due to its lacklustre heat transfer performance. An internally heated screw pyrolysis reactor (IHSPR) was developed by local renewable energy industry, which serves as the research subject for heat transfer performance study of this particular paper. Zero-load heating test (ZLHT) was first carried out to obtain the operational parameters of the reactor, followed by the one dimensional steady-state heat transfer analysis carried out using SolidWorks Flow Simulation 2016. Experiments with feed rate manipulations and pyrolysis products analyses were conducted last to conclude the study.

Development of a Robust Tri-Carbide Fueled Reactor for Multi-Megawatt Space Power and Propulsion Applications

International Nuclear Information System (INIS)

Samim Anghaie; Knight, Travis W.; Plancher, Johann; Gouw, Reza

2004-01-01

An innovative reactor core design based on advanced, mixed carbide fuels was analyzed for nuclear space power applications. Solid solution, mixed carbide fuels such as (U,Zr,Nb)c and (U,Zr, Ta)C offer great promise as an advanced high temperature fuel for space power reactors

Reactor Engineering Division annual report

International Nuclear Information System (INIS)

1980-09-01

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)

Stationary liquid fuel fast reactor SLFFR – Part I: Core design

Energy Technology Data Exchange (ETDEWEB)

Jing, T.; Yang, G.; Jung, Y.S.; Yang, W.S., E-mail: yang494@purdue.edu

2016-12-15

Highlights: • An innovative fast reactor concept SLFFR based on liquid metal fuel is proposed for TRU burning. • A compact core design of 1000 MWt SLFFR is developed to achieve a zero conversion ratio and passive safety. • The core size and the control requirement are significantly reduced compared to the conventional solid fuel reactor with same conversion ratio. - Abstract: For effective burning of hazardous transuranic (TRU) elements of used nuclear fuel, a transformational advanced reactor concept named the stationary liquid fuel fast reactor (SLFFR) has been proposed based on a stationary molten metallic fuel. A compact core design of a 1000 MWt SLFFR has been developed using TRU-Ce-Co fuel, Ta-10W fuel container, and sodium coolant. Conservative design approaches have been adopted to stay within the current material performance database. Detailed neutronics and thermal-fluidic analyses have been performed to evaluate the steady-state performance characteristics. The analysis results indicate that the SLFFR of a zero TRU conversion ratio is feasible while satisfying the conservatively imposed thermal design constraints. A theoretical maximum TRU consumption rate of 1.01 kg/day is achieved with uranium-free fuel. Compared to the solid fuel reactors with the same TRU conversion ratio, the core size and the reactivity control requirement are reduced significantly. The primary and secondary control systems provide sufficient shutdown margins, and the calculated reactivity feedback coefficients show that the prompt fuel expansion coefficient is sufficiently negative.

An ultracold neutron source at the NC State University PULSTAR reactor

Science.gov (United States)

Korobkina, E.; Wehring, B. W.; Hawari, A. I.; Young, A. R.; Huffman, P. R.; Golub, R.; Xu, Y.; Palmquist, G.

2007-08-01

Research and development is being completed for an ultracold neutron (UCN) source to be installed at the PULSTAR reactor on the campus of North Carolina State University (NCSU). The objective is to establish a university-based UCN facility with sufficient UCN intensity to allow world-class fundamental and applied research with UCN. To maximize the UCN yield, a solid ortho-D 2 converter will be implemented coupled to two moderators, D 2O at room temperature, to thermalize reactor neutrons, and solid CH 4, to moderate the thermal neutrons to cold-neutron energies. The source assembly will be located in a tank of D 2O in the space previously occupied by the thermal column of the PULSTAR reactor. Neutrons leaving a bare face of the reactor core enter the D 2O tank through a 45×45 cm cross-sectional area void between the reactor core and the D 2O tank. Liquid He will cool the disk-shaped UCN converter to below 5 K. Independently, He gas will cool the cup-shaped CH 4 cold-neutron moderator to an optimum temperature between 20 and 40 K. The UCN will be transported from the converter to experiments by a guide with an inside diameter of 16 cm. Research areas being considered for the PULSTAR UCN source include time-reversal violation in neutron beta decay, neutron lifetime determination, support measurements for a neutron electric-dipole-moment search, and nanoscience applications.

Reactor Engineering Department annual report

International Nuclear Information System (INIS)

1984-08-01

Research and development activities in the Department of Reactor Engineering in fiscal 1983 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, integral experiment and analysis, fusion neutronics, shielding, reactor and nuclear instrumentation, reactor control and diagnosis, and safeguards technology, and activities of the Committee on Reactor Physics. (author)

Reactor Engineering Division annual report

International Nuclear Information System (INIS)

1976-09-01

Research activities conducted in Reactor Engineering Division in fiscal 1975 are summarized in this report. Works in the division are closely related to the development of multi-purpose High-temperature Gas Cooled Reactor, the development of Liquid Metal Fast Breeder Reactor by Power Reactor and Nuclear Fuel Development Corporation, and engineering research of thermonuclear fusion reactor. Many achievements are described concerning nuclear data and group constants, theoretical method and code development, integral experiment and analysis, shielding, heat transfer and fluid dynamics, reactor and nuclear instrumentation, dynamics analysis and control method development, fusion reactor technology and activities of the Committee on Reactor Physics. (auth.)

In-Vessel Composting of Simulated Long-Term Missions Space-Related Solid Wastes

Science.gov (United States)

Rodriguez-Carias, Abner A.; Sager, John; Krumins, Valdis; Strayer, Richard; Hummerick, Mary; Roberts, Michael S.

2002-01-01

Reduction and stabilization of solid wastes generated during space missions is a major concern for the Advanced Life Support - Resource Recovery program at the NASA, Kennedy Space Center. Solid wastes provide substrates for pathogen proliferation, produce strong odor, and increase storage requirements during space missions. A five periods experiment was conducted to evaluate the Space Operation Bioconverter (SOB), an in vessel composting system, as a biological processing technology to reduce and stabilize simulated long-term missions space related solid-wastes (SRSW). For all periods, SRSW were sorted into components with fast (FBD) and slow (SBD) biodegradability. Uneaten food and plastic were used as a major FBD and SBD components, respectively. Compost temperature (C), CO2 production (%), mass reduction (%), and final pH were utilized as criteria to determine compost quality. In period 1, SOB was loaded with a 55% FBD: 45% SBD mixture and was allowed to compost for 7 days. An eleven day second composting period was conducted loading the SOB with 45% pre-composted SRSW and 55% FBD. Period 3 and 4 evaluated the use of styrofoam as a bulking agent and the substitution of regular by degradable plastic on the composting characteristics of SRSW, respectively. The use of ceramic as a bulking agent and the relationship between initial FBD mass and heat production was investigated in period 5. Composting SRSW resulted in an acidic fermentation with a minor increase in compost temperature, low CO2 production, and slightly mass reduction. Addition of styrofoam as a bulking agent and substitution of regular by biodegradable plastic improved the composting characteristics of SRSW, as evidenced by higher pH, CO2 production, compost temperature and mass reduction. Ceramic as a bulking agent and increase the initial FBD mass (4.4 kg) did not improve the composting process. In summary, the SOB is a potential biological technology for reduction and stabilization of mission space-related

Fischer-Tropsch synthesis in a two-phase reactor with presaturation

Energy Technology Data Exchange (ETDEWEB)

Wache, W. [Bayernoil Raffineriegesellschaft mbH, Ingolstadt (Germany); Datsevich, L.; Jess, A. [Bayreuth Univ. (Germany). Dept. of Chemical Engineering

2006-07-01

In industry, the Fischer-Tropsch (FTS) synthesis is mostly carried out in multiphase slurry or multitubular reactors (MTR), where gaseous reactants and liquid products (hydrocarbons up to waxes) are contacted in the presence of a solid catalyst. Such reactors are characterized by a complex temperature control, necessity of gas recycling, complicated design and problematic scale-up. A new alternative to conventional FTS-processes is the presaturated-one-liquid-phase (POLF) technology. The basic principle of this concept is a recirculation of the liquid phase, in which a gaseous reactant(s) is (are) solved before entering the fixed-bed reactor. In a simple column reactor, this technology ensures the effective heat removal and intensive fluid-solid mass transfer. In comparison to conventional reactors, the plant design is very simple, the temperature control is uncomplicated and there is no danger of any runaways. That results in lower investment and operation costs as well as in higher reliability. The experiments show that the conversion of CO and the product distribution of hydrocarbons are practically independent on the mode of operation (two- or three-phase system). However, in the lab-scale apparatus, water is accumulated in the loop, which leads to a loss of the catalyst activity (due to Fe-carbonate). In a technical process, the water accumulation in a loop can be eluded by taking an oil free of water from the oil work-up unit. Our experiments with the removal of water from the stream by a zeolite demonstrate a much promising applicability of the POLF process to the industrial FTS. (orig.)

Improvements in or relating to nuclear reactors

International Nuclear Information System (INIS)

Savin, N.I.; Khramov, D.A.; Filippov, V.J.; Bugrov, V.V.

1979-01-01

A nuclear reactor is described, comprising a core accommodating a plurality of fuel assemblies and a refuelling device for replacing spent fuel assemblies. The design of the fuel assembly and of the refuelling device, and the method of carrying out the refuelling operation, are specified. (U.K.)

Characteristics of immobilized lactobacillus delbrueckii in a liquid-solid fluidized bed bioreactor for lactic acid production

Energy Technology Data Exchange (ETDEWEB)

Wang, Henian; Seki, M.; Furusaki, S. [The Univ. of Tokyo (Japan). Faculty of Engineering

1995-04-20

A fluidized bed bioreactor was employed for lactic acid production using immobilized cells. First, the cell release rate was discussed. A liquid-solid fluidized bed reactor with immobilized cells was used to perform continuous lactic acid fermentation without any operational problems. The performance of the reactor was investigated under different conditions. Cell release rate and contribution of free cells to lactic acid production were studied quantitatively. The results showed that under low gel holdup and low dilution rate conditions, free cells played a significant role in lactic acid production. However, increasing solid holdup decreased the free cell concentration in the broth due to high lactic acid concentration and also decreased the contribution of the free cells to lactic acid production. The effects of growth nutrients on reactor performance were investigated. 16 refs., 12 figs.

Evaluation of apoptosis and micronucleation induced by reactor neutron beams with two different cadmium ratios in total and quiescent cell populations within solid tumors

International Nuclear Information System (INIS)

Masunaga, Shin-ichiro; Ono, Koji; Sakurai, Yoshinori; Takagaki, Masao; Kobayashi, Tooru; Kinashi, Yuko; Suzuki, Minoru

2001-01-01

Purpose: Response of quiescent (Q) and total tumor cells in solid tumors to reactor neutron beam irradiation with two different cadmium (Cd) ratios was examined in terms of micronucleus (MN) frequency and apoptosis frequency, using four different tumor cell lines. Methods and Materials: C57BL mice bearing EL4 tumors, C3H/He mice bearing SCC VII or FM3A tumors, and Balb/c mice bearing EMT6/KU tumors received 5-bromo-2'-deoxyuridine (BrdU) continuously for 5 days via implanted mini-osmotic pumps to label all proliferating (P) cells. Thirty min after i.p. injection of sodium borocaptate- 10 B (BSH), or 3 h after oral administration of p-boronophenylalanine- 10 B (BPA), the tumors were irradiated with neutron beams. The tumors without 10 B-compound administration were irradiated with neutron beams or γ-rays. This neutron beam irradiation was performed using neutrons with two different Cd ratios. The tumors were then excised, minced, and trypsinized. The tumor cell suspensions thus obtained were incubated with cytochalasin-B (a cytokinesis blocker), and the MN frequency in cells without BrdU labeling (=Q cells) was determined using immunofluorescence staining for BrdU. Meanwhile, for apoptosis assay, 6 h after irradiation, tumor cell suspensions obtained in the same manner were fixed, and the apoptosis frequency in Q cells was also determined with immunofluorescence staining for BrdU. The MN and apoptosis frequencies in total (P+Q) tumor cells were determined from the tumors that were not pretreated with BrdU. Results: Without 10 B-compounds, the sensitivity difference between total and Q cells was reduced by neutron beam irradiation. Under our particular neutron beam irradiation condition, relative biological effectiveness (RBE) of neutrons was larger in Q cells than in total cells, and the RBE values were larger for low Cd-ratio than high Cd-ratio neutrons. With 10 B-compounds, both frequencies were increased for each cell population, especially for total cells. BPA

Catalytic and Gas-Solid Reactions Involving HCN over Limestone

DEFF Research Database (Denmark)

Jensen, Anker; Johnsson, Jan Erik; Dam-Johansen, Kim

1997-01-01

In coal-fired combustion systems solid calcium species may be present as ash components or limestone added to the combustion chamber. In this study heterogeneous reactions involving HCN over seven different limestones were investigated in a laboratory fixed-bed quartz reactor at 873-1,173 K...

The International Science and Technology Center (ISTC) and ISTC projects related to research reactors: information review

Energy Technology Data Exchange (ETDEWEB)

Tocheniy, L. V.; Rudneva, V. Ya. [ISTC, Moscow (Russian Federation)

1998-07-01

The ISTC is an intergovernmental organization established by agreement between the Russian Federation, the European Union, Japan, and the United States. Since 1994, Finland, Sweden, Norway, Georgia, Belarus, Kazakhstan and the Kyrgyz Republic have acceded to the Agreement and Statute. At present, the Republic of Korea is finishing the process of accession to the ISTC. All work of the ISTC is aimed at the goals defined in the ISTC Agreement: To give CIS weapons scientists, particularly those who possess knowledge and skills related to weapons of mass destruction and their delivery systems, the opportunities to redirect their talents to peaceful activities; To contribute to solving national and international technical problems; To support the transition to market-based economics; To support basic and applied research; To help integrate CIS weapons scientists into the international scientific community. The projects may be funded both through governmental funds of the Funding partners of the ISTC. According to the ISTC Statute, approved by the appropriate national organizations, funds used within ISTC projects are exempt from CIS taxes. As of March 1998, more than 1500 proposals had been submitted to the Center, of which 551 were approved for funding, for a total value of approximately US$166 million. The number of scientists and engineers participating in the projects is more than 18000. There are about 20 funded and as yet nonfunded projects related to various problems of research reactors. Many of them address safety issues. Information review of the results and plans of both ongoing projects and as yet nonfunded proposals related to research reactors will be presented with the aim assisting international researchers to establish partnerships or collaboration with ISTC projects. The following groups of ISTC projects will be represented: 1. complex computer simulator s for research reactors; 2. reactor facility decommissioning; 3. neutron sources for medicine; 4

Cleanup Verification Package for the 118-B-1, 105-B Solid Waste Burial Ground

International Nuclear Information System (INIS)

Capron, J.M.

2008-01-01

This cleanup verification package documents completion of remedial action, sampling activities, and compliance criteria for the 118-B-1, 105-B Solid Waste Burial Ground. This waste site was the primary burial ground for general wastes from the operation of the 105-B Reactor and P-10 Tritium Separation Project and also received waste from the 105-N Reactor. The burial ground received reactor hardware, process piping and tubing, fuel spacers, glassware, electrical components, tritium process wastes, soft wastes and other miscellaneous debris

Axial and Radial Gas Holdup in Bubble Column Reactor

International Nuclear Information System (INIS)

Wagh, Sameer M.; Ansari, Mohashin E Alan; Kene, Pragati T.

2014-01-01

Bubble column reactors are considered the reactor of choice for numerous applications including oxidation, hydrogenation, waste water treatment, and Fischer-Tropsch (FT) synthesis. They are widely used in a variety of industrial applications for carrying out gas-liquid and gas-liquid-solid reactions. In this paper, the computational fluid dynamics (CFD) model is used for predicting the gas holdup and its distribution along radial and axial direction are presented. Gas holdup increases linearly with increase in gas velocity. Gas bubbles tends to concentrate more towards the center of the column and follows a wavy path

Transport mechanisms and wetting dynamics in molecularly thin films of long-chain alkanes at solid/vapour interface : relation to the solid-liquid phase transition

OpenAIRE

Lazar, Paul

2005-01-01

Wetting and phase transitions play a very important role our daily life. Molecularly thin films of long-chain alkanes at solid/vapour interfaces (e.g. C30H62 on silicon wafers) are very good model systems for studying the relation between wetting behaviour and (bulk) phase transitions. Immediately above the bulk melting temperature the alkanes wet partially the surface (drops). In this temperature range the substrate surface is covered with a molecularly thin ordered, solid-like alkane film (...

Kinetic modelling of anaerobic hydrolysis of solid wastes, including disintegration processes

Energy Technology Data Exchange (ETDEWEB)

García-Gen, Santiago [Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain); Sousbie, Philippe; Rangaraj, Ganesh [INRA, UR50, Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs, Narbonne F-11100 (France); Lema, Juan M. [Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain); Rodríguez, Jorge, E-mail: jrodriguez@masdar.ac.ae [Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain); Institute Centre for Water and Environment (iWater), Masdar Institute of Science and Technology, PO Box 54224 Abu Dhabi (United Arab Emirates); Steyer, Jean-Philippe; Torrijos, Michel [INRA, UR50, Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs, Narbonne F-11100 (France)

2015-01-15

Highlights: • Fractionation of solid wastes into readily and slowly biodegradable fractions. • Kinetic coefficients estimation from mono-digestion batch assays. • Validation of kinetic coefficients with a co-digestion continuous experiment. • Simulation of batch and continuous experiments with an ADM1-based model. - Abstract: A methodology to estimate disintegration and hydrolysis kinetic parameters of solid wastes and validate an ADM1-based anaerobic co-digestion model is presented. Kinetic parameters of the model were calibrated from batch reactor experiments treating individually fruit and vegetable wastes (among other residues) following a new protocol for batch tests. In addition, decoupled disintegration kinetics for readily and slowly biodegradable fractions of solid wastes was considered. Calibrated parameters from batch assays of individual substrates were used to validate the model for a semi-continuous co-digestion operation treating simultaneously 5 fruit and vegetable wastes. The semi-continuous experiment was carried out in a lab-scale CSTR reactor for 15 weeks at organic loading rate ranging between 2.0 and 4.7 g VS/L d. The model (built in Matlab/Simulink) fit to a large extent the experimental results in both batch and semi-continuous mode and served as a powerful tool to simulate the digestion or co-digestion of solid wastes.

The International conference on fast reactors and related fuel cycles: next generation nuclear systems for sustainable development. Book of abstracts

International Nuclear Information System (INIS)

2017-01-01

The materials of the International Conference on Fast Reactors and Related Fuel Cycles (June 26-29, 2017, Yekaterinburg) are presented. The forum was organized by the IAEA with the assistance of Rosatom State Corporation. The theme of the conference: “The New Generation of Nuclear Systems for Sustainable Development”. About 700 specialists from more than 30 countries took part in the conference. The state and prospects for the development of the direction of fast reactors in countries dealing with this topic were discussed. A wide range of scientific issues covered the concepts of prospective reactors, reactor cores, fuel and fuel cycles, operation and decommissioning, safety, licensing, structural materials, industrial implementation [ru

Tritium diffusion in nonmetallic solids of interest for fusion reactors. Final report

International Nuclear Information System (INIS)

Elleman, T.

1979-01-01

Tritium diffusion measurements have been conducted in Al 2 O 3 , BeO, Y 2 O 3 , SiC, B 4 C, Si 3 N 4 and pyrolytic carbon as a basis for evaluating these materials as potential tritium barriers in fusion reactors. Deuterium solubility measurements were conducted with Al 2 O 3 , SiC and pyrolytic carbon to establish the pressure and temperature dependence of solubility and to identify solubility ranges. Hydrogen permeability measurements on commercially available Al 2 O 3 and SiC materials were used as a check on calculated permeabilities and to provide data on hydrogen permeation rates in polycrystalline materials. The diffusion, solubility and permeation results are presented and discussed in terms of fusion reactor applications

Electrochemical oxidation of recalcitrant organic compounds in biologically treated municipal solid waste leachate in a flow reactor.

Science.gov (United States)

Quan, Xuejun; Cheng, Zhiliang; Chen, Bo; Zhu, Xincai

2013-10-01

Biologically-treated municipal solid waste (MSW) leachate still contains many kinds of bio-recalcitrant organic matter. A new plate and frame electrochemical reactor was designed to treat these materials under flow conditions. In the electrochemical oxidation process, NH3 and color could be easily removed by means of electro-generated chlorine/hypochlorite within 20 min. The effects of major process parameters on the removal of organic pollutants were investigated systematically. Under experimental conditions, the optimum operation parameters were current density of 65 mA/cm2, flow velocity of 2.6 cm/sec in electrode gap, and initial chloride ion concentration of 5000 mg/L. The COD in the leachate could be reduced below 100 mg/L after 1 hr of treatment. The kinetics and mechanism of COD removal were investigated by simultaneously monitoring the COD change and chlorine/hypochlorite production. The kinetics of COD removal exhibited a two-stage kinetic model, and the decrease of electro-generated chlorine/hypochlorite production was the major mechanism for the slowing down of the COD removal rate in the second stage. The narrowing of the electrode gap is beneficial for COD removal and energy consumption.

The operation characteristics of biohydrogen production in continuous stirred tank reactor with molasses

Energy Technology Data Exchange (ETDEWEB)

Hong, C.; Wei, H.; Jie-xuan, D.; Xin, Y.; Chuan-ping, Y. [Northeast Forestry Univ., Harbin (China). School of Forestry; Li, Y.F. [Northeast Forestry Univ., Harbin (China). School of Forestry; Shanghai Univ. Engineering, Shanghai (China). College of Chemistry and Chemical Engineering

2010-07-01

The anaerobic fermentation biohydrogen production in a continuous stirred tank reactor (CSTR) was investigated as a means for treating molasses wastewater. The research demonstrated that the reactor has the capacity of continuously producing hydrogen in an initial biomass (as volatile suspension solids) of 17.74 g/L, temperature of approximately 35 degrees Celsius, hydraulic retention time of 6 hours. The reactor could begin the ethanol-type fermentation in 12 days and realize stable hydrogen production. The study also showed that the CSTR reactor has a favourable stability even with an organic shock loading. The hydrogen yield and chemical oxygen demand (COD) increased, as did the hydrogen content.

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.

Basic research using the 250 KW research reactor triga in Ljubljana, Yugoslavia

International Nuclear Information System (INIS)

Dimic, V.

1983-01-01

The 25 KW Triga Mark II reactor of J. 'Stefan Institute' was commissioned on May 1966. During the last two years, it has been operated for about 4200 hr/year. According to experience gained with the reactor, most of the cost of reactor operation will be earned through isotope production for local hospitals and industries, performing low cost applied experiments and organizing training courses. The rest was provided through the Research Communities of the Republic of Slovenia. The reactor has been operated for 15 years without major problems and many basic research programmes have been performed. The research is being conducted in the following mainfields: solid state physics, neutron dosimetry, neutron radiography and autoradiography, reactor physics, examination of nuclear fuel using gamma scanning, irradiation of semiconducting materials and neutron activation analysis. (A.J)

Fast Reactor Physics. Vol. II. Proceedings of a Symposium on Fast Reactor Physics and Related Safety Problems

International Nuclear Information System (INIS)

1968-01-01

Proceedings of a Symposium organized by the IAEA and held in Karlsruhe, 30 October - 3 November 1967. The meeting was attended by 183 scientists from 23 countries and three international organizations. Contents: (Vol.1) Review of national programmes (5 papers); Nuclear data for fast reactors (12 papers); Experimental methods (3 papers); Zoned systems (7 papers); Kinetics (7 papers). (Vol.11) Fast critical experiments (8 papers); Heterogeneity in fast critical experiments (5 papers); Fast power reactors (13 papers); Fast pulsed reactors (3 papers); Panel discussion. Each paper is in its original language (50 English, 11 French and 3 Russian) and is preceded by an abstract in English with a second one in the original language if this is not English. Discussions are in English. (author)

Sandia Pulsed Reactor Facility (SPRF) calculator-assisted pulse analysis and display system

International Nuclear Information System (INIS)

Estes, B.F.; Berry, D.T.

1980-02-01

Two solid-metal fast burst type reactors (SPR II and SPR III) are operated at the Sandia Pulsed Reactor Facility. Since startup of the reactors, oscilloscope traces have been used to record (by camera) the pulse (power) shape while log N systems have measured initial reactor period. Virtually no other pulse information is available. A decision was made to build a system that could collect the basic input data available from the reactor - fission chambers, photodiodes, and thermocouples - condition the signals and output the various parameters such as power, energy, temperature, period and lifetime on hard copy that would provide a record for operations personnel as well as the experimenter. Because the reactors operate in short time frames - pulse operation - it is convenient to utilize the classical Nordheim-Fuchs approximation of the diffusion equation to describe reactor behavior. This report describes the work performed to date in developing the calculator system and analytical models for computing the desired parameters

Performance and kinetic study of semi-dry thermophilic anaerobic digestion of organic fraction of municipal solid waste

International Nuclear Information System (INIS)

Sajeena Beevi, B.; Madhu, G.; Sahoo, Deepak Kumar

2015-01-01

Highlights: • Performance of the reactor was evaluated by the degradation of volatile solids. • Biogas yield at the end of the digestion was 52.9 L/kg VS. • Value of reaction rate constant, k, obtained was 0.0249 day −1 . • During the digestion 66.7% of the volatile solid degradation was obtained. - Abstract: Anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) is promoted as an energy source and waste disposal. In this study semi dry anaerobic digestion of organic solid wastes was conducted for 45 days in a lab-scale batch experiment for total solid concentration of 100 g/L for investigating the start-up performances under thermophilic condition (50 °C). The performance of the reactor was evaluated by measuring the daily biogas production and calculating the degradation of total solids and the total volatile solids. The biogas yield at the end of the digestion was 52.9 L/kg VS (volatile solid) for the total solid (TS) concentration of 100 g/L. About 66.7% of the volatile solid degradation was obtained during the digestion. A first order model based on the availability of substrate as the limiting factor was used to perform the kinetic studies of batch anaerobic digestion system. The value of reaction rate constant, k, obtained was 0.0249 day −1

Performance and kinetic study of semi-dry thermophilic anaerobic digestion of organic fraction of municipal solid waste

Energy Technology Data Exchange (ETDEWEB)

Sajeena Beevi, B., E-mail: sajeenanazer@gmail.com [Department of Chemical Engineering, Govt. Engineering College, Thrissur, Kerala 680 009 (India); Madhu, G., E-mail: profmadhugopal@gmail.com [Division of Safety & Fire Engineering, School of Engineering, Cochin University of Science and Technology, Cochin, Kerala 682 022 (India); Sahoo, Deepak Kumar, E-mail: dksahoo@gmail.com [Division of Safety & Fire Engineering, School of Engineering, Cochin University of Science and Technology, Cochin, Kerala 682 022 (India)

2015-02-15

Highlights: • Performance of the reactor was evaluated by the degradation of volatile solids. • Biogas yield at the end of the digestion was 52.9 L/kg VS. • Value of reaction rate constant, k, obtained was 0.0249 day{sup −1}. • During the digestion 66.7% of the volatile solid degradation was obtained. - Abstract: Anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) is promoted as an energy source and waste disposal. In this study semi dry anaerobic digestion of organic solid wastes was conducted for 45 days in a lab-scale batch experiment for total solid concentration of 100 g/L for investigating the start-up performances under thermophilic condition (50 °C). The performance of the reactor was evaluated by measuring the daily biogas production and calculating the degradation of total solids and the total volatile solids. The biogas yield at the end of the digestion was 52.9 L/kg VS (volatile solid) for the total solid (TS) concentration of 100 g/L. About 66.7% of the volatile solid degradation was obtained during the digestion. A first order model based on the availability of substrate as the limiting factor was used to perform the kinetic studies of batch anaerobic digestion system. The value of reaction rate constant, k, obtained was 0.0249 day{sup −1}.

Spectral shift reactor control method

International Nuclear Information System (INIS)

Impink, A.J. Jr.

1981-01-01

A method of operating a nuclear reactor having a core and coolant displacer elements arranged in the core wherein is established a reator coolant temperature set point at which it is desired to operate said reactor and first reactor coolant temperature band limits are provided within which said set point is located and it is desired to operate said reactor charactrized in that said reactor coolant displacer elements are moved relative to the reactor core for adjusting the volume of reactor coolant in said core as said reactor coolant temperature approaches said first band limits thereby to maintain said reactor coolant temperature near said set point and within said first band limits

Cold neutron source conceptual designing for Tehran Research Reactor

International Nuclear Information System (INIS)

Khajvand, N.; Mirvakili, S.M.; Faghihi, F.

2016-01-01

Highlights: • Cold neutron source conceptual designing for Tehran research reactor is carried out. • Type and geometry of moderator and dimensions of cold neutron source are analyzed. • Liquid hydrogen with more ortho-concentration can be better option as moderator. - Abstract: A cold neutron source (CNS) conceptual designing for the Tehran Research Reactor (TRR) were carried out using MCNPX code. In this study, a horizontal beam tube of the core which has appropriate the highest thermal flux is selected and parametric analysis to choose the type and geometry of the moderator, and the required CNS dimensions for maximizing the cold neutron production was performed. In this design the moderator cell has a spherical annulus structure, and the cold neutron flux and its brightness are calculated together with the nuclear heat load of the CNS for a variety of materials including liquid hydrogen, liquid deuterium, and solid methane. Based on our study, liquid hydrogen with more ortho-concentration than para and solid methane are the best options.

Advanced Test Reactor Safety Basis Upgrade Lessons Learned Relative to Design Basis Verification and Safety Basis Management

International Nuclear Information System (INIS)

G. L. Sharp; R. T. McCracken

2004-01-01

The Advanced Test Reactor (ATR) is a pressurized light-water reactor with a design thermal power of 250 MW. The principal function of the ATR is to provide a high neutron flux for testing reactor fuels and other materials. The reactor also provides other irradiation services such as radioisotope production. The ATR and its support facilities are located at the Test Reactor Area of the Idaho National Engineering and Environmental Laboratory (INEEL). An audit conducted by the Department of Energy's Office of Independent Oversight and Performance Assurance (DOE OA) raised concerns that design conditions at the ATR were not adequately analyzed in the safety analysis and that legacy design basis management practices had the potential to further impact safe operation of the facility.1 The concerns identified by the audit team, and issues raised during additional reviews performed by ATR safety analysts, were evaluated through the unreviewed safety question process resulting in shutdown of the ATR for more than three months while these concerns were resolved. Past management of the ATR safety basis, relative to facility design basis management and change control, led to concerns that discrepancies in the safety basis may have developed. Although not required by DOE orders or regulations, not performing design basis verification in conjunction with development of the 10 CFR 830 Subpart B upgraded safety basis allowed these potential weaknesses to be carried forward. Configuration management and a clear definition of the existing facility design basis have a direct relation to developing and maintaining a high quality safety basis which properly identifies and mitigates all hazards and postulated accident conditions. These relations and the impact of past safety basis management practices have been reviewed in order to identify lessons learned from the safety basis upgrade process and appropriate actions to resolve possible concerns with respect to the current ATR safety

TREATMENT OF METHANOLIC WASTEWATER BY ANAEROBIC DOWN-FLOW HANGING SPONGE (ANDHS) REACTOR AND UASB REACTOR

Science.gov (United States)

Sumino, Haruhiko; Wada, Keiji; Syutsubo, Kazuaki; Yamaguchi, Takashi; Harada, Hideki; Ohashi, Akiyoshi

Anaerobic down-flow hanging sponge (AnDHS) reactor and UASB reactor were operated at 30℃ for over 400 days in order to investigate the process performance and the sludge characteristics of treating methanolic wastewater (2 gCOD/L). The settings OLR of AnDHS reactor and of UASB reactor were 5.0 -10.0 kgCOD/m3/d and 5.0 kgCOD/m3/d. The average of the COD removal demonstrated by both reactors were over 90% throughout the experiment. From the results of methane producing activities and the PCR-DGGE method, most methanol was directly converted to methane in both reactors. The conversion was carried out by different methanogens: one closely related to Methanomethylovorans hollandica in the AnDHS retainted sludge and the other closely related to Methanosarcinaceae and Metanosarciales in the UASB retainted sludge.

Flow-injection spectrophotometric determination of captopril in pharmaceutical formulations using a new solid-phase reactor containing AgSCN immobilized in a polyurethane resin

Directory of Open Access Journals (Sweden)

Fernando Campanhã Vicentini

2012-06-01

Full Text Available A simple flow-injection analysis procedure was developed for determining captopril in pharmaceutical formulations employing a novel solid-phase reactor containing silver thiocyanate immobilized in a castor oil derivative polyurethane resin. The method was based on silver mercaptide formation between the captopril and Ag(I in the solid-phase reactor. During such a reaction, the SCN- anion was released and reacted with Fe3+, which generated the FeSCN2+ complex that was continuously monitored at 480 nm. The analytical curve was linear in the captopril concentration range from 3.0 × 10-4 mol L-1 to 1.1 × 10-3 mol L-1 with a detection limit of 8.0 × 10-5 mol L-1. Recoveries between 97.5% and 103% and a relative standard deviation of 2% for a solution containing 6.0 × 10-4 mol L-1 captopril (n = 12 were obtained. The sample throughput was 40 h-1 and the results obtained for captopril in pharmaceutical formulations using this procedure and those obtained using a pharmacopoeia procedure were in agreement at a 95% confidence level.Um procedimento simples de análise por injeção em fluxo foi desenvolvido para a determinação de captopril em formulações farmacêuticas empregando um novo reator em fase sólida contendo tiocianato de prata imobilizado em resina poliuretana obtida a partir de óleo de mamona. O método foi baseado na formação de um mercapto composto de prata, no reator em fase sólida, obtido entre o captopril e Ag (I imobilizada. Durante a reação, íons SCN- eram liberados e reagiam com Fe3+, gerando o complexo FeSCN2+, que foi continuamente monitorado em 480 nm. A curva analítica foi linear no intervalo de concentração de captopril entre 3,0 × 10-4 a 1,1 × 10-3 mol L-1 com um limite de detecção de 8,0 × 10-5 mol L-1. Recuperações entre 97,5-103% e desvio padrão relativo de 2% para uma solução contendo 6,0 × 10-4 mol L-1 de captopril (n = 12 foram obtidos. A frequência de amostragem foi de 40 h-1 e os resultados

Power Trip Set-points of Reactor Protection System for New Research Reactor

International Nuclear Information System (INIS)

Lee, Byeonghee; Yang, Soohyung

2013-01-01

This paper deals with the trip set-point related to the reactor power considering the reactivity induced accident (RIA) of new research reactor. The possible scenarios of reactivity induced accidents were simulated and the effects of trip set-point on the critical heat flux ratio (CHFR) were calculated. The proper trip set-points which meet the acceptance criterion and guarantee sufficient margins from normal operation were then determined. The three different trip set-points related to the reactor power are determined based on the RIA of new research reactor during FP condition, over 0.1%FP and under 0.1%FP. Under various reactivity insertion rates, the CHFR are calculated and checked whether they meet the acceptance criterion. For RIA at FP condition, the acceptance criterion can be satisfied even if high power set-point is only used for reactor trip. Since the design of the reactor is still progressing and need a safety margin for possible design changes, 18 MW is recommended as a high power set-point. For RIA at 0.1%FP, high power setpoint of 18 MW and high log rate of 10%pp/s works well and acceptance criterion is satisfied. For under 0.1% FP operations, the application of high log rate is necessary for satisfying the acceptance criterion. Considering possible decrease of CHFR margin due to design changes, the high log rate is suggested to be 8%pp/s. Suggested trip set-points have been identified based on preliminary design data for new research reactor; therefore, these trip set-points will be re-established by considering design progress of the reactor. The reactor protection system (RPS) of new research reactor is designed for safe shutdown of the reactor and preventing the release of radioactive material to environment. The trip set point of RPS is essential for reactor safety, therefore should be determined to mitigate the consequences from accidents. At the same time, the trip set-point should secure margins from normal operational condition to avoid

Reactor Engineering Division annual report

International Nuclear Information System (INIS)

1975-11-01

Research activities in fiscal 1974 in Reactor Engineering Division of eight laboratories and computing center are described. Works in the division are closely related with the development of a multi-purpose High-temperature Gas Cooled Reactor, the development of a Liquid Metal Fast Breeder Reactor in Power Reactor and Nuclear Fuel Development Corporation, and engineering of thermonuclear fusion reactors. They cover nuclear data and group constants, theoretical method and code development, integral experiment and analysis, shielding, heat transfer and fluid dynamics, reactor and nuclear instrumentation, dynamics analysis and control method development, fusion reactor technology and aspects of the computing center. (auth.)

The BGU/CERN solar hydrothermal reactor

CERN Document Server

Bertolucci, Sergio; Caspers, Fritz; Garb, Yaakov; Gross, Amit; Pauletta, Stefano

2014-01-01

We describe a novel solar hydrothermal reactor (SHR) under development by Ben Gurion University (BGU) and the European Organization for Nuclear Research CERN. We describe in broad terms the several novel aspects of the device and, by extension, of the niche it occupies: in particular, enabling direct off-grid conversion of a range of organic feedstocks to sterile useable (solid, liquid) fuels, nutrients, products using only solar energy and water. We then provide a brief description of the high temperature high efficiency panels that provide process heat to the hydrothermal reactor, and review the basics of hydrothermal processes and conversion taking place in this. We conclude with a description of a simulation of the pilot system that will begin operation later this year.

Nuclear reactor design

CERN Document Server

2014-01-01

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

The source term and waste optimization of molten salt reactors with processing

International Nuclear Information System (INIS)

Gat, U.; Dodds, H.L.

1993-01-01

The source term of a molten salt reactor (MSR) with fuel processing is reduced by the ratio of processing time to refueling time as compared to solid fuel reactors. The reduction, which can be one to two orders of magnitude, is due to removal of the long-lived fission products. The waste from MSRs can be optimized with respect to its chemical composition, concentration, mixture, shape, and size. The actinides and long-lived isotopes can be separated out and returned to the reactor for transmutation. These features make MSRs more acceptable and simpler in operation and handling

Pellets used for nuclear reactor scram and a method for manufacturing them

International Nuclear Information System (INIS)

1974-01-01

The invention deals with a pellet to be inserted in the core of a nuclear reactor for stopping the operation of the latter. The pellet is characterized in that it is in the form of a pellet capable of rolling easily, containing a neutron poison and a solid substance undergoing a change of state when it is raised to a predetermined temperature reached by the reactor-core, that change of state causing the pellet to desintegrate and inducing the deposition of the poison. This can be applied to the shut down of gas-cooled nuclear reactors [fr

Advanced Test Reactor (ATR) Facility 10CFR830 Safety Basis Related to Facility Experiments

International Nuclear Information System (INIS)

Tomberlin, T.A.

2002-01-01

The Idaho National Engineering and Environmental Laboratory (INEEL) Advanced Test Reactor (ATR), a DOE Category A reactor, was designed to provide an irradiation test environment for conducting a variety of experiments. The ATR Safety Analysis Report, determined by DOE to meet the requirements of 10 CFR 830, Subpart B, provides versatility in types of experiments that may be conducted. This paper addresses two general types of experiments in the ATR facility and how safety analyses for experiments are related to the ATR safety basis. One type of experiment is more routine and generally represents greater risks; therefore this type of experiment is addressed with more detail in the safety basis. This allows individual safety analyses for these experiments to be more routine and repetitive. The second type of experiment is less defined and is permitted under more general controls. Therefore, individual safety analyses for the second type of experiment tend to be more unique from experiment to experiment. Experiments are also discussed relative to ''major modifications'' and DOE-STD-1027-92. Application of the USQ process to ATR experiments is also discussed

Two Stage Anaerobic Reactor Design and Treatment To Produce Biogas From Mixed Liquor of Vegetable Waste

Science.gov (United States)

Budiastuti, H.; Ghozali, M.; Wicaksono, H. K.; Hadiansyah, R.

2018-01-01

Municipal solid waste has become a common challenged problem to be solved for developing countries including Indonesia. Municipal solid waste generating is always bigger than its treatment to reduce affect of environmental pollution. This research tries to contribute to provide an alternative solution to treat municipal solid waste to produce biogas. Vegetable waste was obtained from Gedebage Market, Bandung and starter as a source of anaerobic microorganisms was cow dung obtained from a cow farm in Lembang. A two stage anaerobic reactor was designed and built to treat the vegetable waste in a batch run. The capacity of each reactor is 20 liters but its active volume in each reactor is 15 liters. Reactor 1 (R1) was fed up with mixture of filtered blended vegetable waste and water at ratio of 1:1 whereas Reactor 2 (R2) was filled with filtered mixed liquor of cow dung and water at ratio of 1:1. Both mixtures were left overnight before use. Into R1 it was added EM-4 at concentration of 10%. pH in R1 was maintained at 5 - 6.5 whereas pH in R1 was maintained at 6.5 - 7.5. Temperature of reactors was not maintained to imitate the real environmental temperature. Parameters taken during experiment were pH, temperature, COD, MLVSS, and composition of biogas. The performance of reactor built was shown from COD efficiencies reduction obtained of about 60% both in R1 and R2, pH average in R1 of 4.5 ± 1 and R2 of 7 ± 0.6, average temperature in both reactors of 25 ± 2°C. About 1L gas produced was obtained during the last 6 days of experiment in which CH4 obtained was 8.951 ppm and CO2 of 1.087 ppm. The maximum increase of MLVSS in R1 reached 156% and R2 reached 89%.

Status review of large fast reactor core designs and their dynamics related features

International Nuclear Information System (INIS)

Spenke, H.; Kiefhaber, E.

1982-01-01

Since several years conventional and unconventional concepts of large fast reactor cores have been investigated in the Federal Republic of Germany at INTERATOM and Kernforschungszentrum Karlsruhe. The work was performed jointly with Belgonucleaire (Belgium). Basically, the studies were aimed at the determination of the performance potential of different core concepts for large fast reactors. Thus the following points were considered: power distribution, neutron fluence and residence time, doubling time, uranium ore consumption, dynamics and safety related features, economics, cooling strategy, core element bowing behaviour. In this paper, the state of the analysis will be presented with emphasis on those points relevant for this meeting. However, we have to make clear, that dynamic and accident studies are still under way and that we are not yet able to cover these aspects in a quantitative manner. This is due to the fact, that the efforts in the DeBeNe-countries have been concentrated on the work necessary for being granted the different licenses for SNR 300, fast breeder prototype reactor near Kalkar. As we expect to obtain these important licenses at the beginning of 1982, an increased man power can be devoted to studies of dynamic and safety problems of large fast cores from that time on. These studies have to fit into the planning recently announced by the utility ESK who will be ordering SNR 2, the first demonstration breeder reactor of Germany, Belgium, Netherlands and France. The planning calls for concept decisions in 1983, leading to an engineering contract for SNR 2 in 1983/1984. Accordingly we shall have to complete and evaluate the ongoing core concept Investigations till 1983 resulting in a subsequent final choice

Status of research reactor utilization and other related activities

International Nuclear Information System (INIS)

Calix, V.S.

2004-01-01

The report covers two parts; the first is on the progress of the cooperative projects planned for 2002 under the FNCA and the other part on the activities related to the PRR1, Philippine Research Reactor. In the 2001 Workshop at Beijing, the Country agreed to participate in the three areas for collaboration. A brief reports on these three projects are included. The Country representatives during this 2002 Workshop will do a more detailed presentation on Radioisotope Production (TcG) and Neutron Activation Analysis projects. The second part of this report deals with the issues/concerns impeding the rehabilitation of PRR1. In January 2002, the Institute created the PRR1 Strategic Plan Committee to look deeply into these issues and concerns. The results of the Committee's work are discussed. (author)

Biological nitrogen and carbon removal in a gravity flow biomass concentrator reactor for municipal sewage treatment.

Science.gov (United States)

Scott, Daniel; Hidaka, Taira; Campo, Pablo; Kleiner, Eric; Suidan, Makram T; Venosa, Albert D

2013-01-01

A novel membrane system, the Biomass Concentrator Reactor (BCR), was evaluated as an alternative technology for the treatment of municipal wastewater. Because the BCR is equipped with a membrane whose average poresize is 20 μm (18-28 μm), the reactor requires low-pressure differential to operate (gravity). The effectiveness of this system was evaluated for the removal of carbon and nitrogen using two identical BCRs, identified as conventional and hybrid, that were operated in parallel. The conventional reactor was operated under full aerobic conditions (i.e., organic carbon and ammonia oxidation), while the hybrid reactor incorporated an anoxic zone for nitrate reduction as well as an aerobic zone for organic carbon and ammonia oxidation. Both reactors were fed synthetic wastewater at a flow rate of 71 L d(-1), which resulted in a hydraulic retention time of 9 h. In the case of the hybrid reactor, the recycle flow from the aerobic zone to the anoxic zone was twice the feed flow rate. Reactor performance was evaluated under two solids retention times (6 and 15 d). Under these conditions, the BCRs achieved nearly 100% mixed liquor solids separation with a hydraulic head differential of less than 2.5 cm. The COD removal efficiency was over 90%. Essentially complete nitrification was achieved in both systems, and nitrogen removal in the hybrid reactor was close to the expected value (67%). Copyright © 2012 Elsevier Ltd. All rights reserved.

Treatment of slaughterhouse wastewater in anaerobic sequencing batch reactors

Energy Technology Data Exchange (ETDEWEB)

Masse, D. I.; Masse, L. [Agriculture and Agri-Food Canada, Lennoxville, PQ (Canada)

2000-09-01

Slaughterhouse waste water was treated in anaerobic sequencing batch reactors operated at 30 degrees C. Two of the batch reactors were seeded with anaerobic granular sludge from a milk processing plant reactor; two others received anaerobic non-granulated sludge from a municipal waste water treatment plant. Influent total chemical oxygen demand was reduced by 90 to 96 per cent at organic loading rates ranging from 2.07 kg to 4.93 kg per cubic meter. Reactors seeded with municipal sludge performed slightly better than those containing sludge from the milk processing plant. The difference was particularly noticeable during start-up, but the differences between the two sludges were reduced with time. The reactors produced a biogas containing 75 per cent methane. About 90.5 per cent of the chemical oxygen demand removed was methanized; volatile suspended solids accumulation was determined at 0.068 kg per kg of chemical oxygen demand removed. The high degree of methanization suggests that most of the soluble and suspended organic material in slaughterhouse waste water was degraded during the treatment in the anaerobic sequencing batch reactors. 30 refs., 1 tab., 6 figs.

Characterization of the solid radioactive waste From Cernavoda NPP

International Nuclear Information System (INIS)

Iordache, M.; Laotaru, V.

2005-01-01

Full text: During the operation of a nuclear plant significant quantities of radioactive waste result that have a very large diversity. At Cernavoda NPP large amounts of wastes are either non-radioactive wastes or radioactive wastes, each of these being managed completely different from which other. For a CANDU type reactor, the appearance of radioactive wastes is due to contamination with the following types of radioactive substances: - fission products resulting from nuclear fuel burning; - activated products from materials composing the technological systems; - activated products in process fluids. Radioactive wastes can be in solid, liquid or gas form. At Cernavoda NPP the solid wastes represent about 70% of the waste volume which is produced during plant operation and as a consequence of maintenance and decontamination operations. The most important types of solid wastes that are obtained and then handled, processed (if necessary) and temporarily stored are: solid low-level radioactive wastes (classified as compactible and non-compactible), solid medium radioactive wastes, spent resins, used filters and filter cartridges. The liquid radioactive waste class includes organic liquids (used oil, scintillator liquids and used solvents) and aqueous wastes resulting from process system operating, from decontamination and maintenance operations. Radioactive gas wastes occur subsequently to the fission process inside the fuel elements as well as due to the neutron activation of process fluids in the reactor systems. As result of plant operation, iodine, noble gases, tritium and radioactive particles occur and are passed toward the ventilation stack in a controlled manner so that environmental release of radioactive materials with concentrations exceeding the maximum permissible level could not occur. (authors)