Compact hydrogen production systems for solid polymer fuel cells

Science.gov (United States)

Ledjeff-Hey, K.; Formanski, V.; Kalk, Th.; Roes, J.

Generally there are several ways to produce hydrogen gas from carbonaceous fuels like natural gas, oil or alcohols. Most of these processes are designed for large-scale industrial production and are not suitable for a compact hydrogen production system (CHYPS) in the power range of 1 kW. In order to supply solid polymer fuel cells (SPFC) with hydrogen, a compact fuel processor is required for mobile applications. The produced hydrogen-rich gas has to have a low level of harmful impurities; in particular the carbon monoxide content has to be lower than 20 ppmv. Integrating the reaction step, the gas purification and the heat supply leads to small-scale hydrogen production systems. The steam reforming of methanol is feasible at copper catalysts in a low temperature range of 200-350°C. The combination of a small-scale methanol reformer and a metal membrane as purification step forms a compact system producing high-purity hydrogen. The generation of a SPFC hydrogen fuel gas can also be performed by thermal or catalytic cracking of liquid hydrocarbons such as propane. At a temperature of 900°C the decomposition of propane into carbon and hydrogen takes place. A fuel processor based on this simple concept produces a gas stream with a hydrogen content of more than 90 vol.% and without CO and CO2.

Plasma gasification of refuse derived fuel in a single-stage system using different gasifying agents.

Science.gov (United States)

Agon, N; Hrabovský, M; Chumak, O; Hlína, M; Kopecký, V; Masláni, A; Bosmans, A; Helsen, L; Skoblja, S; Van Oost, G; Vierendeels, J

2016-01-01

The renewable evolution in the energy industry and the depletion of natural resources are putting pressure on the waste industry to shift towards flexible treatment technologies with efficient materials and/or energy recovery. In this context, a thermochemical conversion method of recent interest is plasma gasification, which is capable of producing syngas from a wide variety of waste streams. The produced syngas can be valorized for both energetic (heat and/or electricity) and chemical (ammonia, hydrogen or liquid hydrocarbons) end-purposes. This paper evaluates the performance of experiments on a single-stage plasma gasification system for the treatment of refuse-derived fuel (RDF) from excavated waste. A comparative analysis of the syngas characteristics and process yields was done for seven cases with different types of gasifying agents (CO2+O2, H2O, CO2+H2O and O2+H2O). The syngas compositions were compared to the thermodynamic equilibrium compositions and the performance of the single-stage plasma gasification of RDF was compared to that of similar experiments with biomass and to the performance of a two-stage plasma gasification process with RDF. The temperature range of the experiment was from 1400 to 1600 K and for all cases, a medium calorific value syngas was produced with lower heating values up to 10.9 MJ/Nm(3), low levels of tar, high levels of CO and H2 and which composition was in good agreement to the equilibrium composition. The carbon conversion efficiency ranged from 80% to 100% and maximum cold gas efficiency and mechanical gasification efficiency of respectively 56% and 95%, were registered. Overall, the treatment of RDF proved to be less performant than that of biomass in the same system. Compared to a two-stage plasma gasification system, the produced syngas from the single-stage reactor showed more favourable characteristics, while the recovery of the solid residue as a vitrified slag is an advantage of the two-stage set-up. Copyright �

Roll compaction and granulation system for nuclear fuel material

International Nuclear Information System (INIS)

Goldmann, L.H. Jr.; Holley, C.C.

1981-01-01

A roll compaction and roll granulation system has been designed and fabricated to replace conventional preslugging and crushing operations typically used in the fabrication of mixed oxide nuclear fuel pellets. This equipment will be of maintenance advantage with only the compaction and granulation rolls inside containment. The prototype is being tested and the results will be reported within a year

35-We polymer electrolyte membrane fuel cell system for notebook computer using a compact fuel processor

Science.gov (United States)

Son, In-Hyuk; Shin, Woo-Cheol; Lee, Yong-Kul; Lee, Sung-Chul; Ahn, Jin-Gu; Han, Sang-Il; kweon, Ho-Jin; Kim, Ju-Yong; Kim, Moon-Chan; Park, Jun-Yong

A polymer electrolyte membrane fuel cell (PEMFC) system is developed to power a notebook computer. The system consists of a compact methanol-reforming system with a CO preferential oxidation unit, a 16-cell PEMFC stack, and a control unit for the management of the system with a d.c.-d.c. converter. The compact fuel-processor system (260 cm 3) generates about 1.2 L min -1 of reformate, which corresponds to 35 We, with a low CO concentration (notebook computers.

Dimensional Behavior of Matrix Graphite Compacts during Heat Treatments for HTGR Fuel Element Fabrication

International Nuclear Information System (INIS)

Lee, Young-Woo; Yeo, Seunghwan; Cho, Moon Sung

2015-01-01

The carbonization is a process step where the binder that is incorporated during the matrix graphite powder preparation step is evaporated and the residue of the binder is carbonized during the heat treatment at about 1073 K. This carbonization step is followed by the final high temperature heat treatment where the carbonized compacts are heat treated at 2073-2173 K in vacuum for a relatively short time (about 2 hrs). In order to develop a fuel compact fabrication technology, and for fuel matrix graphite to meet the required material properties, it is essential to investigate the relationship among the process parameters of the matrix graphite powder preparation, the fabrication parameters of fuel element green compact and the heat treatments conditions, which has a strong influence on the further steps and the material properties of fuel element. In this work, the dimensional changes of green compacts during the carbonization and final heat treatment are evaluated when compacts have different densities from different pressing conditions and different final heat treatment temperatures are employed, keeping other process parameters constant, such as the binder content, carbonization time, temperature and atmosphere (two hours ant 1073K and N2 atmosphere). In this work, the dimensional variations of green compacts during the carbonization and final heat treatment are evaluated when compacts have different densities from different pressing conditions and different final heat treatment temperatures are employed

Ceramographic Examinations of Irradiated AGR-1 Fuel Compacts

Energy Technology Data Exchange (ETDEWEB)

Paul Demkowicz; Scott Ploger; John Hunn

2012-05-01

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

Ceramographic Examinations of Irradiated AGR-1 Fuel Compacts

International Nuclear Information System (INIS)

Demkowicz, Paul; Ploger, Scott; Hunn, John

2012-01-01

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

35-We polymer electrolyte membrane fuel cell system for notebook computer using a compact fuel processor

Energy Technology Data Exchange (ETDEWEB)

Son, In-Hyuk; Shin, Woo-Cheol; Lee, Sung-Chul; Ahn, Jin-Gu; Han, Sang-Il; kweon, Ho-Jin; Kim, Ju-Yong; Park, Jun-Yong [Energy 1 Group, Energy Laboratory at Corporate R and D Center in Samsung SDI Co., Ltd., 575, Shin-dong, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-731 (Korea); Lee, Yong-Kul [Department of Chemical Engineering, Dankook University, Youngin 448-701 (Korea); Kim, Moon-Chan [Department of Environmental Engineering, Chongju University, Chongju 360-764 (Korea)

2008-10-15

A polymer electrolyte membrane fuel cell (PEMFC) system is developed to power a notebook computer. The system consists of a compact methanol-reforming system with a CO preferential oxidation unit, a 16-cell PEMFC stack, and a control unit for the management of the system with a d.c.-d.c. converter. The compact fuel-processor system (260 cm{sup 3}) generates about 1.2 L min{sup -1} of reformate, which corresponds to 35 We, with a low CO concentration (<30 ppm, typically 0 ppm), and is thus proven to be capable of being targetted at notebook computers. (author)

Compact toroid injection fueling in a large field-reversed configuration

Science.gov (United States)

Asai, T.; Matsumoto, T.; Roche, T.; Allfrey, I.; Gota, H.; Sekiguchi, J.; Edo, T.; Garate, E.; Takahashi, Ts.; Binderbauer, M.; Tajima, T.

2017-07-01

A repetitively driven compact toroid (CT) injector has been developed for the large field-reversed configuration (FRC) facility of the C-2/C-2U, primarily for particle refueling. A CT is formed and injected by a magnetized coaxial plasma gun (MCPG) exclusively developed for the C-2/C-2U FRC. To refuel the particles of long-lived FRCs, multiple CT injections are required. Thus, a multi-stage discharge circuit was developed for a multi-pulsed CT injection. The drive frequency of this system can be adjusted up to 1 kHz and the number of CT shots per injector is two; the system can be further upgraded for a larger number of injection pulses. The developed MCPG can achieve a supersonic ejection velocity in the range of ~100 km s-1. The key plasma parameters of electron density, electron temperature and the number of particles are ~5  ×  1021 m-3, ~30 eV and 0.5-1.0  ×  1019, respectively. In this project, single- and double-pulsed counter CT injection fueling were conducted on the C-2/C-2U facility by two CT injectors. The CT injectors were mounted 1 m apart in the vicinity of the mid-plane. To avoid disruptive perturbation on the FRC, the CT injectors were operated at the lower limit of the particle inventory. The experiments demonstrated successful refueling with a significant density build-up of 20-30% of the FRC particle inventory per single CT injection without any deleterious effects on the C-2/C-2U FRC.

Monitoring of homogeneity of fuel compacts for high-temperature reactors

International Nuclear Information System (INIS)

Mottet, P.; Guery, M.; Chegne, J.

Apparatus using either gamma transmission or gamma scintillation spectrometry (with NaI(Tl) detector) was developed for monitoring the homogeneity of distribution of fissile and fertile particles in fuel compacts for high-temperature reactors. Three methods were studied: Longitudinal gamma transmission which gives a total distribution curve of heavy metals (U and Th); gamma spectrometry with a well type scintillator, which rapidly gives the U and Th count rates per fraction of compact; and longitudinal gamma spectrometry, giving axial distribution curves for uranium and thorium; apparatus with four scintillators and optimization of the parameters for the measurement, permitting significantly decreasing the duration of the monitoring. These relatively simple procedures should facilitate the industrial monitoring of high-temperature reactor fuel

Two-stage DNA compaction induced by silver ions suggests a cooperative binding mechanism

Science.gov (United States)

Jiang, Wen-Yan; Ran, Shi-Yong

2018-05-01

The interaction between silver ions and DNA plays an important role in the therapeutic use of silver ions and in related technologies such as DNA sensors. However, the underlying mechanism has not been fully understood. In this study, the dynamics of Ag+-DNA interaction at a single-molecule level was studied using magnetic tweezers. AgNO3 solutions with concentrations ranging from 1 μM to 20 μM led to a 1.4-1.8 μm decrease in length of a single λ-DNA molecule, indicating that Ag+ has a strong binding with DNA, causing the DNA conformational change. The compaction process comprises one linear declining stage and another sigmoid-shaped stage, which can be attributed to the interaction mechanism. Considering the cooperative effect, the sigmoid trend was well explained using a phenomenological model. By contrast, addition of silver nanoparticle solution induced no detectable transition of DNA. The dependence of the interaction on ionic strength and DNA concentration was examined via morphology characterization and particle size distribution measurement. The size of the Ag+-DNA complex decreased with an increase in Ag+ ionic strength ranging from 1 μM to 1 mM. Morphology characterization confirmed that silver ions induced DNA to adopt a compacted globular conformation. At a fixed [AgNO3]:[DNA base pairs] ratio, increasing DNA concentration led to increased sizes of the complexes. Intermolecular interaction is believed to affect the Ag+-DNA complex formation to a large extent.

NOFBX Single-Stage-to-Orbit Mars Ascent Vehicle Engine, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — We propose the continuation of our research and development of a Nitrous Oxide Fuel Blend (NOFBXTM) Single-Stage-to-Orbit (SSTO) monopropellant propulsion system for...

Compact PEM fuel cell system combined with all-in-one hydrogen generator using chemical hydride as a hydrogen source

International Nuclear Information System (INIS)

Kim, Jincheol; Kim, Taegyu

2015-01-01

Highlights: • Compact fuel cell system was developed for a portable power generator. • Novel concept using an all-in-one reactor for hydrogen generation was proposed. • Catalytic reactor, hydrogen chamber and separator were combined in a volume. • The system can be used to drive fuel cell-powered unmanned autonomous systems. - Abstract: Compact fuel cell system was developed for a portable power generator. The power generator features a polymer electrolyte membrane fuel cell (PEMFC) using a chemical hydride as a hydrogen source. The hydrogen generator extracted hydrogen using a catalytic hydrolysis from a sodium borohydride alkaline solution. A novel concept using an all-in-one reactor was proposed in which a catalyst, hydrogen chamber and byproduct separator were combined in a volume. In addition, the reactor as well as a pump, cooling fans, valves and controller was integrated in a single module. A 100 W PEMFC stack was connected with the hydrogen generator and was evaluated at various load conditions. It was verified that the stable hydrogen supply was achieved and the developed system can be used to drive fuel cell-powered unmanned autonomous systems.

Normal and compact spent fuel storage in light water reactor power plants

International Nuclear Information System (INIS)

Kuenel, R.R.

1978-01-01

The compact storage of light water reactor spent fuel is a safe, cheap and reliable contribution towards overcoming the momentarily existing shortage in spent fuel reprocessing. The technical concept is described and physical behaviour discussed. The introduction of compact storage racks in nuclear power plants increases the capacity from 100 to about 240 %. The increase in decay heat is not more than about 14%, the increase in activity inventory and hazard potential does not exceed 20%. In most cases the existing power plant equipment fulfils the new requirements. (author)

Determination of uranium in coated fuel particle compact by potassium fluoride fusion-gravimetric method

International Nuclear Information System (INIS)

Ito, Mitsuo; Iso, Shuichi; Hoshino, Akira; Suzuki, Shuichi.

1992-03-01

Potassium fluoride-gravimetric method has been developed for the determination of uranium in TRISO type-coated fuel particle compact. Graphite matrix in the fuel compact is burned off by heating it in a platinum crucible at 850degC. The coated fuel particles thus obtained are decomposed by fusion with potassium fluoride at 900degC. The melt was dissolved with sulfuric acid. Uranium is precipitated as ammonium diuranate, by passing ammonia gas through the solution. The resulting precipitate is heated in a muffle furnace at 850degC, to convert uranium into triuranium octoxide. Uranium in the triuranium octoxide was determined gravimetrically. Ten grams of caoted fuel particles were completely decomposed by fusion with 50 g of potassium fluoride at 900degC for 3 hrs. Analytical result for uranium in the fuel compact by the proposed method was 21.04 ± 0.05 g (n = 3), and was in good agreement with that obtained by non-destructive γ-ray measurement method : 21.01 ± 0.07 g (n = 3). (author)

Measurement of Weight of Kernels in a Simulated Cylindrical Fuel Compact for HTGR

International Nuclear Information System (INIS)

Kim, Woong Ki; Lee, Young Woo; Kim, Young Min; Kim, Yeon Ku; Eom, Sung Ho; Jeong, Kyung Chai; Cho, Moon Sung; Cho, Hyo Jin; Kim, Joo Hee

2011-01-01

The TRISO-coated fuel particle for the high temperature gas-cooled reactor (HTGR) is composed of a nuclear fuel kernel and outer coating layers. The coated particles are mixed with graphite matrix to make HTGR fuel element. The weight of fuel kernels in an element is generally measured by the chemical analysis or a gamma-ray spectrometer. Although it is accurate to measure the weight of kernels by the chemical analysis, the samples used in the analysis cannot be put again in the fabrication process. Furthermore, radioactive wastes are generated during the inspection procedure. The gamma-ray spectrometer requires an elaborate reference sample to reduce measurement errors induced from the different geometric shape of test sample from that of reference sample. X-ray computed tomography (CT) is an alternative to measure the weight of kernels in a compact nondestructively. In this study, X-ray CT is applied to measure the weight of kernels in a cylindrical compact containing simulated TRISO-coated particles with ZrO 2 kernels. The volume of kernels as well as the number of kernels in the simulated compact is measured from the 3-D density information. The weight of kernels was calculated from the volume of kernels or the number of kernels. Also, the weight of kernels was measured by extracting the kernels from a compact to review the result of the X-ray CT application

Multi-stage internal gear/turbine fuel pump

Energy Technology Data Exchange (ETDEWEB)

Maier, Eugen; Raney, Michael Raymond

2004-07-06

A multi-stage internal gear/turbine fuel pump for a vehicle includes a housing having an inlet and an outlet and a motor disposed in the housing. The multi-stage internal gear/turbine fuel pump also includes a shaft extending axially and disposed in the housing. The multi-stage internal gear/turbine fuel pump further includes a plurality of pumping modules disposed axially along the shaft. One of the pumping modules is a turbine pumping module and another of the pumping modules is a gerotor pumping module for rotation by the motor to pump fuel from the inlet to the outlet.

Early stage fuel cell funding

International Nuclear Information System (INIS)

Bergeron, C.

2004-01-01

'Full text:' Early stage venture funding requires an in depth understanding of both current and future markets as well as the key technical hurdles that need to be overcome for new technology to commercialize into successful products for mass markets. As the leading fuel cell and hydrogen investor, Chrysalix continuously reviews global trends and new technologies, evaluates them with industry leaders worldwide and tries to match them up with the best possible management teams when selecting its early stage investments. Chrysalix Energy Limited Partnership is an early-stage venture capital firm focusing on fuel cell and related fueling technology companies and is a private equity joint venture between Ballard Power Systems, BASF Venture Capital, The BOC Group, The Boeing Company, Duke Energy, Mitsubishi Corporation and Shell Hydrogen. Operating independently, Chrysalix offers a unique value proposition to its clients throughout the business planning, start-up and operations phases of development. Chrysalix provides early-stage funding to new companies as well as management assistance, technological knowledge, organized networking with industry players and experience in the management of intellectual property. (author)

Moisture desorption in mechanically masticated fuels: effects of particle fracturing and fuelbed compaction

Science.gov (United States)

Jesse K. Kreye; J.Morgan Varner; Eric E. Knapp

2012-01-01

Mechanical mastication is increasingly used as a wildland fuel treatment, reducing standing trees and shrubs to compacted fuelbeds of fractured woody fuels. One major shortcoming in our understanding of these fuelbeds is how particle fracturing influences moisture gain or loss, a primary determinant of fire behaviour. To better understand fuel moisture dynamics, we...

Ash related behaviour in staged and non-staged combustion of biomass fuels and fuel mixtures

International Nuclear Information System (INIS)

Becidan, Michaël; Todorovic, Dusan; Skreiberg, Øyvind; Khalil, Roger A.; Backman, Rainer; Goile, Franziska; Skreiberg, Alexandra; Jovovic, Aleksandar; Sørum, Lars

2012-01-01

The fate of selected elements (with focus on the important players in corrosion i.e. Na, K, Pb, Zn, Cl and S) are investigated for three biomasses (wood, demolition wood and coffee waste) and six mixtures of these as pellets both with and without air staging in a laboratory reactor. In order to get a complete overview of the combustion products, both online and offline analytical methods are used. Information is collected about: flue gas composition, particle (fly ash) size distribution and composition, bottom ash composition and melting properties. The main findings are: (1) complex interactions are taking place between the mixed fuels during combustion; (2) the mode of occurrence of an element as well as the overall structure of the fuel are important for speciation; (3) the pelletisation process, by bringing chemical elements into intimate contact, may affect partitioning and speciation; (4) staging and mixing might simultaneously have positive and negative effects on operation; (5) staging affects the governing mechanisms of fly ash (aerosols) formation. -- Highlights: ► Complex interactions are taking place between the mixed fuels during combustion. ► The mode of occurrence of an element as well as the overall structure of the fuel are important for speciation. ► The pelletisation process, by bringing chemical elements into intimate contact, may affect partitioning and speciation. ► Staging and mixing might simultaneously have positive and negative effects on operation. ► Staging affects the governing mechanisms of fly ash (aerosols) formation.

Numerical studies of a compact gasoline reformer for fuel cell vehicle applications

International Nuclear Information System (INIS)

McIntyre, C.S.; Harrison, S.J.; Oosthuizen, P.H.; Peppley, B.A.

2004-01-01

There has been recent interest in the development of compact fuel processors to produce hydrogen for fuel cell powered vehicles. Gasoline is a promising candidate for distributed or on-board processing because of its high energy density and well-developed infrastructure. A compact fuel processor is under development which utilizes autothermal reforming (ATR) to extract hydrogen from iso-octane, which is used as a surrogate for gasoline. The processor consists of a double-pass packed-bed catalytic reactor to promote partial oxidation, steam reforming, and water-gas-shift reactions. As part of this system development, a commercial computational fluid dynamics (CFD) package was used to model flow and chemical reactions. Reformer performance is presented in terms of hydrogen content in the product stream, reformer efficiency (LHV efficiency) and iso-octane conversion. Results are compared to on-going experimental studies. (author)

Fuel management strategy for the compact core design of RSG GAS (MPR-30)

Energy Technology Data Exchange (ETDEWEB)

Sembiring, T.M.; Liem, P.H.; Tukiran, S. [National Nuclear Energy Agency (Batan), PUSPIPTEK-Serpong Tangerang (Indonesia)

2000-07-01

The rearrangement of the core configuration of the RSG GAS reactor to obtain a compact core is in progress. A fuel management strategy is proposed for the equilibrium compact core of this reactor by reducing the number of in-core irradiation positions. The reduced irradiation positions are based on the activities during 12 years operation. The obtained compact core gives significant extension of the operation cycle length so that the reactor availability and utilization can be enhanced. The equilibrium compact silicide core obtained met the imposed design constraints and safety requirements. (author)

Fuel management strategy for the compact core design of RSG GAS (MPR-30)

International Nuclear Information System (INIS)

Sembiring, T.M.; Liem, P.H.; Tukiran, S.

2000-01-01

The rearrangement of the core configuration of the RSG GAS reactor to obtain a compact core is in progress. A fuel management strategy is proposed for the equilibrium compact core of this reactor by reducing the number of in-core irradiation positions. The reduced irradiation positions are based on the activities during 12 years operation. The obtained compact core gives significant extension of the operation cycle length so that the reactor availability and utilization can be enhanced. The equilibrium compact silicide core obtained met the imposed design constraints and safety requirements. (author)

Updated baseline for a staged Compact Linear Collider

CERN Document Server

Boland, M J; Giansiracusa, P J; Lucas, T G; Rassool, R P; Balazs, C; Charles, T K; Afanaciev, K; Emeliantchik, I; Ignatenko, A; Makarenko, V; Shumeiko, N; Patapenka, A; Zhuk, I; Abusleme Hoffman, A C; Diaz Gutierrez, M A; Gonzalez, M Vogel; Chi, Y; He, X; Pei, G; Pei, S; Shu, G; Wang, X; Zhang, J; Zhao, F; Zhou, Z; Chen, H; Gao, Y; Huang, W; Kuang, Y P; Li, B; Li, Y; Shao, J; Shi, J; Tang, C; Wu, X; Ma, L; Han, Y; Fang, W; Gu, Q; Huang, D; Huang, X; Tan, J; Wang, Z; Zhao, Z; Laštovička, T; Uggerhoj, U; Wistisen, T N; Aabloo, A; Eimre, K; Kuppart, K; Vigonski, S; Zadin, V; Aicheler, M; Baibuz, E; Brücken, E; Djurabekova, F; Eerola, P; Garcia, F; Haeggström, E; Huitu, K; Jansson, V; Karimaki, V; Kassamakov, I; Kyritsakis, A; Lehti, S; Meriläinen, A; Montonen, R; Niinikoski, T; Nordlund, K; Österberg, K; Parekh, M; Törnqvist, N A; Väinölä, J; Veske, M; Farabolini, W; Mollard, A; Napoly, O; Peauger, F; Plouin, J; Bambade, P; Chaikovska, I; Chehab, R; Davier, M; Kaabi, W; Kou, E; LeDiberder, F; Pöschl, R; Zerwas, D; Aimard, B; Balik, G; Baud, J-P; Blaising, J-J; Brunetti, L; Chefdeville, M; Drancourt, C; Geoffroy, N; Jacquemier, J; Jeremie, A; Karyotakis, Y; Nappa, J M; Vilalte, S; Vouters, G; Bernard, A; Peric, I; Gabriel, M; Simon, F; Szalay, M; van der Kolk, N; Alexopoulos, T; Gazis, E N; Gazis, N; Ikarios, E; Kostopoulos, V; Kourkoulis, S; Gupta, P D; Shrivastava, P; Arfaei, H; Dayyani, M K; Ghasem, H; Hajari, S S; Shaker, H; Ashkenazy, Y; Abramowicz, H; Benhammou, Y; Borysov, O; Kananov, S; Levy, A; Levy, I; Rosenblat, O; D'Auria, G; Di Mitri, S; Abe, T; Aryshev, A; Higo, T; Makida, Y; Matsumoto, S; Shidara, T; Takatomi, T; Takubo, Y; Tauchi, T; Toge, N; Ueno, K; Urakawa, J; Yamamoto, A; Yamanaka, M; Raboanary, R; Hart, R; van der Graaf, H; Eigen, G; Zalieckas, J; Adli, E; Lillestøl, R; Malina, L; Pfingstner, J; Sjobak, K N; Ahmed, W; Asghar, M I; Hoorani, H; Bugiel, S; Dasgupta, R; Firlej, M; Fiutowski, T A; Idzik, M; Kopec, M; Kuczynska, M; Moron, J; Swientek, K P; Daniluk, W; Krupa, B; Kucharczyk, M; Lesiak, T; Moszczynski, A; Pawlik, B; Sopicki, P; Wojtoń, T; Zawiejski, L; Kalinowski, J; Krawczyk, M; Żarnecki, A F; Firu, E; Ghenescu, V; Neagu, A T; Preda, T; Zgura, I-S; Aloev, A; Azaryan, N; Budagov, J; Chizhov, M; Filippova, M; Glagolev, V; Gongadze, A; Grigoryan, S; Gudkov, D; Karjavine, V; Lyablin, M; Olyunin, A; Samochkine, A; Sapronov, A; Shirkov, G; Soldatov, V; Solodko, A; Solodko, E; Trubnikov, G; Tyapkin, I; Uzhinsky, V; Vorozhtov, A; Levichev, E; Mezentsev, N; Piminov, P; Shatilov, D; Vobly, P; Zolotarev, K; Bozovic-Jelisavcic, I; Kacarevic, G; Lukic, S; Milutinovic-Dumbelovic, G; Pandurovic, M; Iriso, U; Perez, F; Pont, M; Trenado, J; Aguilar-Benitez, M; Calero, J; Garcia-Tabares, L; Gavela, D; Gutierrez, J L; Lopez, D; Toral, F; Moya, D; Ruiz-Jimeno, A; Vila, I; Argyropoulos, T; Blanch Gutierrez, C; Boronat, M; Esperante, D; Faus-Golfe, A; Fuster, J; Fuster Martinez, N; Galindo Muñoz, N; García, I; Giner Navarro, J; Ros, E; Vos, M; Brenner, R; Ekelöf, T; Jacewicz, M; Ögren, J; Olvegård, M; Ruber, R; Ziemann, V; Aguglia, D; Alipour Tehrani, N; Aloev, A; Andersson, A; Andrianala, F; Antoniou, F; Artoos, K; Atieh, S; Ballabriga Sune, R; Barnes, M J; Barranco Garcia, J; Bartosik, H; Belver-Aguilar, C; Benot Morell, A; Bett, D R; Bettoni, S; Blanchot, G; Blanco Garcia, O; Bonnin, X A; Brunner, O; Burkhardt, H; Calatroni, S; Campbell, M; Catalan Lasheras, N; Cerqueira Bastos, M; Cherif, A; Chevallay, E; Constance, B; Corsini, R; Cure, B; Curt, S; Dalena, B; Dannheim, D; De Michele, G; De Oliveira, L; Deelen, N; Delahaye, J P; Dobers, T; Doebert, S; Draper, M; Duarte Ramos, F; Dubrovskiy, A; Elsener, K; Esberg, J; Esposito, M; Fedosseev, V; Ferracin, P; Fiergolski, A; Foraz, K; Fowler, A; Friebel, F; Fuchs, J-F; Fuentes Rojas, C A; Gaddi, A; Garcia Fajardo, L; Garcia Morales, H; Garion, C; Gatignon, L; Gayde, J-C; Gerwig, H; Goldblatt, A N; Grefe, C; Grudiev, A; Guillot-Vignot, F G; Gutt-Mostowy, M L; Hauschild, M; Hessler, C; Holma, J K; Holzer, E; Hourican, M; Hynds, D; Inntjore Levinsen, Y; Jeanneret, B; Jensen, E; Jonker, M; Kastriotou, M; Kemppinen, J M K; Kieffer, R B; Klempt, W; Kononenko, O; Korsback, A; Koukovini Platia, E; Kovermann, J W; Kozsar, C-I; Kremastiotis, I; Kulis, S; Latina, A; Leaux, F; Lebrun, P; Lefevre, T; Linssen, L; Llopart Cudie, X; Maier, A A; Mainaud Durand, H; Manosperti, E; Marelli, C; Marin Lacoma, E; Martin, R; Mazzoni, S; Mcmonagle, G; Mete, O; Mether, L M; Modena, M; Münker, R M; Muranaka, T; Nebot Del Busto, E; Nikiforou, N; Nisbet, D; Nonglaton, J-M; Nuiry, F X; Nürnberg, A; Olvegard, M; Osborne, J; Papadopoulou, S; Papaphilippou, Y; Passarelli, A; Patecki, M; Pazdera, L; Pellegrini, D; Pepitone, K; Perez, F; Perez Codina, E; Perez Fontenla, A; Persson, T H B; Petrič, M; Pitters, F; Pittet, S; Plassard, F; Rajamak, R; Redford, S; Renier, Y; Rey, S F; Riddone, G; Rinolfi, L; Rodriguez Castro, E; Roloff, P; Rossi, C; Rude, V; Rumolo, G; Sailer, A; Santin, E; Schlatter, D; Schmickler, H; Schulte, D; Shipman, N; Sicking, E; Simoniello, R; Skowronski, P K; Sobrino Mompean, P; Soby, L; Sosin, M P; Sroka, S; Stapnes, S; Sterbini, G; Ström, R; Syratchev, I; Tecker, F; Thonet, P A; Timeo, L; Timko, H; Tomas Garcia, R; Valerio, P; Vamvakas, A L; Vivoli, A; Weber, M A; Wegner, R; Wendt, M; Woolley, B; Wuensch, W; Uythoven, J; Zha, H; Zisopoulos, P; Benoit, M; Vicente Barreto Pinto, M; Bopp, M; Braun, H H; Csatari Divall, M; Dehler, M; Garvey, T; Raguin, J Y; Rivkin, L; Zennaro, R; Aksoy, A; Nergiz, Z; Pilicer, E; Tapan, I; Yavas, O; Baturin, V; Kholodov, R; Lebedynskyi, S; Miroshnichenko, V; Mordyk, S; Profatilova, I; Storizhko, V; Watson, N; Winter, A; Goldstein, J; Green, S; Marshall, J S; Thomson, M A; Xu, B; Gillespie, W A; Pan, R; Tyrk, M A; Protopopescu, D; Robson, A; Apsimon, R; Bailey, I; Burt, G; Constable, D; Dexter, A; Karimian, S; Lingwood, C; Buckland, M D; Casse, G; Vossebeld, J; Bosco, A; Karataev, P; Kruchinin, K; Lekomtsev, K; Nevay, L; Snuverink, J; Yamakawa, E; Boisvert, V; Boogert, S; Boorman, G; Gibson, S; Lyapin, A; Shields, W; Teixeira-Dias, P; West, S; Jones, R; Joshi, N; Bodenstein, R; Burrows, P N; Christian, G B; Gamba, D; Perry, C; Roberts, J; Clarke, J A; Collomb, N A; Jamison, S P; Shepherd, B J A; Walsh, D; Demarteau, M; Repond, J; Weerts, H; Xia, L; Wells, J D; Adolphsen, C; Barklow, T; Breidenbach, M; Graf, N; Hewett, J; Markiewicz, T; McCormick, D; Moffeit, K; Nosochkov, Y; Oriunno, M; Phinney, N; Rizzo, T; Tantawi, S; Wang, F; Wang, J; White, G; Woodley, M

2016-01-01

The Compact Linear Collider (CLIC) is a multi-TeV high-luminosity linear e+e- collider under development. For an optimal exploitation of its physics potential, CLIC is foreseen to be built and operated in a staged approach with three centre-of-mass energy stages ranging from a few hundred GeV up to 3 TeV. The first stage will focus on precision Standard Model physics, in particular Higgs and top-quark measurements. Subsequent stages will focus on measurements of rare Higgs processes, as well as searches for new physics processes and precision measurements of new states, e.g. states previously discovered at LHC or at CLIC itself. In the 2012 CLIC Conceptual Design Report, a fully optimised 3 TeV collider was presented, while the proposed lower energy stages were not studied to the same level of detail. This report presents an updated baseline staging scenario for CLIC. The scenario is the result of a comprehensive study addressing the performance, cost and power of the CLIC accelerator complex as a function of...

Aerodynamic Performance of a Compact, High Work-Factor Centrifugal Compressor at the Stage and Subcomponent Level

Science.gov (United States)

Braunscheidel, Edward P.; Welch, Gerard E.; Skoch, Gary J.; Medic, Gorazd; Sharma, Om P.

2015-01-01

The measured aerodynamic performance of a compact, high work-factor, single-stage centrifugal compressor, comprising an impeller, diffuser, 90deg-bend, and exit guide vane is reported. Performance levels are based on steady-state total-pressure and total-temperature rake and angularity-probe data acquired at key machine rating planes during recent testing at NASA Glenn Research Center. Aerodynamic performance at the stage level is reported for operation between 70 to 105 percent of design corrected speed, with subcomponent (impeller, diffuser, and exit-guide-vane) flow field measurements presented and discussed at the 100 percent design-speed condition. Individual component losses from measurements are compared with pre-test CFD predictions on a limited basis.

Concept of automated system for spent fuel utilization ('Reburning') from compact nuclear reactors

International Nuclear Information System (INIS)

Ianovski, V.V.; Lozhkin, O.V.; Nesterov, M.M.; Tarasov, N.A.; Uvarov, V.I.

1997-01-01

On the basic concept of an automated system of nuclear power installation safety is developed the utilization project of spent fuel from compact nuclear reactors. The main features of this project are: 1. design and creation of the mobile model-industrial installation; 2. development of the utilization and storage diagram of the spent fuel from compact nuclear reactors, with the specific recommendation for the natatorial means using both for the nuclear fuel reburning, for its transportation in places of the storage; 3. research of an opportunity during the utilization process to obtain additional power resources, ozone and others to increase of justifying expenses at the utilization; 4. creation of new generation engineering for the automation of remote control processes in the high radiation background conditions. 7 refs., 1 fig

Detection and analysis of particles with failed SiC in AGR-1 fuel compacts

Energy Technology Data Exchange (ETDEWEB)

Hunn, John D., E-mail: hunnjd@ornl.gov [Oak Ridge National Laboratory (ORNL), P.O. Box 2008, Oak Ridge, TN 37831-6093 (United States); Baldwin, Charles A.; Gerczak, Tyler J.; Montgomery, Fred C.; Morris, Robert N.; Silva, Chinthaka M. [Oak Ridge National Laboratory (ORNL), P.O. Box 2008, Oak Ridge, TN 37831-6093 (United States); Demkowicz, Paul A.; Harp, Jason M.; Ploger, Scott A. [Idaho National Laboratory (INL), P.O. Box 1625, Idaho Falls, ID 83415-6188 (United States)

2016-09-15

Highlights: • Cesium release was used to detect SiC failure in HTGR fuel. • Tristructural-isotropic particles with SiC failure were isolated by gamma screening. • SiC failure was studied by X-ray tomography and SEM. • SiC degradation was observed after irradiation and subsequent safety testing. - Abstract: As the primary barrier to release of radioactive isotopes emitted from the fuel kernel, retention performance of the SiC layer in tristructural isotropic (TRISO) coated particles is critical to the overall safety of reactors that utilize this fuel design. Most isotopes are well-retained by intact SiC coatings, so pathways through this layer due to cracking, structural defects, or chemical attack can significantly contribute to radioisotope release. In the US TRISO fuel development effort, release of {sup 134}Cs and {sup 137}Cs are used to detect SiC failure during fuel compact irradiation and safety testing because the amount of cesium released by a compact containing one particle with failed SiC is typically ten or more times higher than that released by compacts without failed SiC. Compacts with particles that released cesium during irradiation testing or post-irradiation safety testing at 1600–1800 °C were identified, and individual particles with abnormally low cesium retention were sorted out with the Oak Ridge National Laboratory (ORNL) Irradiated Microsphere Gamma Analyzer (IMGA). X-ray tomography was used for three-dimensional imaging of the internal coating structure to locate low-density pathways through the SiC layer and guide subsequent materialography by optical and scanning electron microscopy. All three cesium-releasing particles recovered from as-irradiated compacts showed a region where the inner pyrocarbon (IPyC) had cracked due to radiation-induced dimensional changes in the shrinking buffer and the exposed SiC had experienced concentrated attack by palladium; SiC failures observed in particles subjected to safety testing were

Detection and Analysis of Particles with Failed SiC in AGR-1 Fuel Compacts

International Nuclear Information System (INIS)

Hunn, John D.; Baldwin, Charles A.; Gerczak, Tyler J.; Montgomery, Fred C.; Morris, Robert N.; Silva, Chinthaka M.; Demkowicz, Paul A.; Harp, Jason M.; Ploger, Scott A.

2014-01-01

As the primary barrier to release of radioactive isotopes emitted from the fuel kernel, retention performance of the SiC layer in tristructural isotropic (TRISO) coated particles is critical to the overall safety of reactors that utilize this fuel design. Most isotopes are well-retained by intact SiC coatings, so pathways through this layer due to cracking, structural defects, or chemical attack can significantly contribute to radioisotope release. In the US TRISO fuel development effort, release of "1"3"4Cs and "1"3"7Cs are used to detect SiC failure during fuel compact irradiation and safety testing because the amount of cesium released by a compact containing one particle with failed SiC is typically ten or more times higher than that released by compacts without failed SiC. Compacts with particles that released cesium during the AGR-1 irradiation test or post-irradiation safety testing at 1600– 1800°C were identified, and individual particles with abnormally low cesium retention were sorted out with the ORNL Irradiated Microsphere Gamma Analyzer (IMGA). X-ray tomography was used for three-dimensional imaging of the internal coating structure to locate low-density pathways through the SiC layer and guide subsequent materialography by optical and scanning electron microscopy. All three cesium-releasing particles recovered from as-irradiated compacts showed a region where the inner pyrocarbon (IPyC) had cracked due to radiation-induced dimensional changes in the shrinking buffer and the exposed SiC had experienced concentrated attack by palladium; SiC failures observed in particles subjected to safety testing were related to either fabrication defects or showed extensive Pd corrosion through the SiC where it had been exposed by similar IPyC cracking. (author)

Compactly supported linearised observables in single-field inflation

Energy Technology Data Exchange (ETDEWEB)

Fröob, Markus B.; Higuchi, Atsushi [Department of Mathematics, University of York, Heslington, York, YO10 5DD (United Kingdom); Hack, Thomas-Paul, E-mail: mbf503@york.ac.uk, E-mail: thomas-paul.hack@itp.uni-leipzig.de, E-mail: atsushi.higuchi@york.ac.uk [Institut für Theoretische Physik, Universität Leipzig, Brüderstraße 16, 04103 Leipzig (Germany)

2017-07-01

We investigate the gauge-invariant observables constructed by smearing the graviton and inflaton fields by compactly supported tensors at linear order in general single-field inflation. These observables correspond to gauge-invariant quantities that can be measured locally. In particular, we show that these observables are equivalent to (smeared) local gauge-invariant observables such as the linearised Weyl tensor, which have better infrared properties than the graviton and inflaton fields. Special cases include the equivalence between the compactly supported gauge-invariant graviton observable and the smeared linearised Weyl tensor in Minkowski and de Sitter spaces. Our results indicate that the infrared divergences in the tensor and scalar perturbations in single-field inflation have the same status as in de Sitter space and are both a gauge artefact, in a certain technical sense, at tree level.

Impacts of burnup-dependent swelling of metallic fuel on the performance of a compact breed-and-burn fast reactor

Energy Technology Data Exchange (ETDEWEB)

Hartanto, Donny; Heo, Woong; Kim, Chi Hyung; Kim, Yong Hee [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon (Korea, Republic of)

2016-04-15

The U-Zr or U-TRU-Zr cylindrical metallic fuel slug used in fast reactors is known to swell significantly and to grow during irradiation. In neutronics simulations of metallic-fueled fast reactors, it is assumed that the slug has swollen and contacted cladding, and the bonding sodium has been removed from the fuel region. In this research, a realistic burnup-dependent fuel-swelling simulation was performed using Monte Carlo code McCARD for a single-batch compact sodium-cooled breed-and-burn reactor by considering the fuel-swelling behavior reported from the irradiation test results in EBR-II. The impacts of the realistic burnup-dependent fuel swelling are identified in terms of the reactor neutronics performance, such as core lifetime, conversion ratio, axial power distribution, and local burnup distributions. It was found that axial fuel growth significantly deteriorated the neutron economy of a breed-and-burn reactor and consequently impaired its neutronics performance. The bonding sodium also impaired neutron economy, because it stayed longer in the blanket region until the fuel slug reached 2% burnup.

Development of compaction technique for spent fuel skeletons

Energy Technology Data Exchange (ETDEWEB)

Yoon, Ji Sup; Kim, Young Hwan; Jung, Jae Hoo [Korea Atomic Energy Research Institute, Taejon (Korea)

1999-12-01

To increase the utilization of uranium resources contained in the spent fuel, the spent fuel is reused. For this, the spent fuel is dismantled or spent fuel rod is extracted from the spent fuel assembly. When the rod is extracted, the remaining components of spent fuel assembly, so called a NFBC(Non-Fuel Bearing Components), should be compacted for the final disposal. To this end, several companies developed the NFBC compactors. German company, named as GNS has developed the direct compression devices of the NFBCs for the rod consolidation and installed it at the PKA(2) of pilot conditioning plant. B and W (Babcock and Wilcox) in USA adopted cutting method rather than the compression method and developed the special cutting devices of NFBC which can be applied underwater environment. In this study the characteristics of these two methods was investigated, in terms of fabrication cost of devices, maintainability in a high radioactive environment, required power and work volume for operation. Also, the optimal power source is selected by comparing the maximum power versus the work volume for operation. In addition to these, the reduction ratio of the bulk volume is obtained while varying the cutting length of the NFBC through a series of experiments. Based on the results of analysis and experiments, the cutting method after compression is selected as an optimal volume reduction method and its design specification is obtained. 8 refs., 62 figs., 32 tabs. (Author)

Durability Properties of Palm Oil Fuel Ash Self Compacting Concrete

Directory of Open Access Journals (Sweden)

T. Ofuyatan

2015-02-01

Full Text Available Self Compacting Concrete (SCC is a new innovation in technology that can flow readily into place under its own self weight and fill corner areas of reinforcement structures without the need to vibrate and without segregation of its constitute. The problem of durability of concrete structures due to inadequate compaction by skilled workers has become a source of concern globally. The shortage of skilled manpower, noise and vibration of equipment on construction sites has led to the development of self compacting concrete. This paper presents an experimental study on the durability properties of Self Compacting Concrete with partial placement of Palm Oil Fuel Ash (POFA. Twelve POFA self-compacting concretes of various strength grades were designed at varying percentages of 0, 5, 10, 15, 20, 25 and 30%. The concrete with no placement of ash served as control. Conplast SP432MS was used as superplasticiser in the mix. The experiments are carried out by adopting a water-powder ratio of 0.36. Workability of the fresh concrete is determined by using tests such as: slump flow, T50, V-funnel and L-Box tests. The durability of concrete is tested by acid resistance, sulphate attack and saturated water absorption at the age of 14, 28, 56 and 90 days.

Raytheon's next generation compact inline cryocooler architecture

Science.gov (United States)

Schaefer, B. R.; Bellis, L.; Ellis, M. J.; Conrad, T.

2014-01-01

Since the 1970s, Raytheon has developed, built, tested and integrated high performance cryocoolers. Our versatile designs for single and multi-stage cryocoolers provide reliable operation for temperatures from 10 to 200 Kelvin with power levels ranging from 50 W to nearly 600 W. These advanced cryocoolers incorporate clearance seals, flexure suspensions, hermetic housings and dynamic balancing to provide long service life and reliable operation in all relevant environments. Today, sensors face a multitude of cryocooler integration challenges such as exported disturbance, efficiency, scalability, maturity, and cost. As a result, cryocooler selection is application dependent, oftentimes requiring extensive trade studies to determine the most suitable architecture. To optimally meet the needs of next generation passive IR sensors, the Compact Inline Raytheon Stirling 1-Stage (CI-RS1), Compact Inline Raytheon Single Stage Pulse Tube (CI-RP1) and Compact Inline Raytheon Hybrid Stirling/Pulse Tube 2-Stage (CI-RSP2) cryocoolers are being developed to satisfy this suite of requirements. This lightweight, compact, efficient, low vibration cryocooler combines proven 1-stage (RS1 or RP1) and 2-stage (RSP2) cold-head architectures with an inventive set of warm-end mechanisms into a single cooler module, allowing the moving mechanisms for the compressor and the Stirling displacer to be consolidated onto a common axis and in a common working volume. The CI cryocooler is a significant departure from the current Stirling cryocoolers in which the compressor mechanisms are remote from the Stirling displacer mechanism. Placing all of the mechanisms in a single volume and on a single axis provides benefits in terms of package size (30% reduction), mass (30% reduction), thermodynamic efficiency (>20% improvement) and exported vibration performance (≤25 mN peak in all three orthogonal axes at frequencies from 1 to 500 Hz). The main benefit of axial symmetry is that proven balancing

Raytheon's next generation compact inline cryocooler architecture

International Nuclear Information System (INIS)

Schaefer, B. R.; Bellis, L.; Ellis, M. J.; Conrad, T.

2014-01-01

Since the 1970s, Raytheon has developed, built, tested and integrated high performance cryocoolers. Our versatile designs for single and multi-stage cryocoolers provide reliable operation for temperatures from 10 to 200 Kelvin with power levels ranging from 50 W to nearly 600 W. These advanced cryocoolers incorporate clearance seals, flexure suspensions, hermetic housings and dynamic balancing to provide long service life and reliable operation in all relevant environments. Today, sensors face a multitude of cryocooler integration challenges such as exported disturbance, efficiency, scalability, maturity, and cost. As a result, cryocooler selection is application dependent, oftentimes requiring extensive trade studies to determine the most suitable architecture. To optimally meet the needs of next generation passive IR sensors, the Compact Inline Raytheon Stirling 1-Stage (CI-RS1), Compact Inline Raytheon Single Stage Pulse Tube (CI-RP1) and Compact Inline Raytheon Hybrid Stirling/Pulse Tube 2-Stage (CI-RSP2) cryocoolers are being developed to satisfy this suite of requirements. This lightweight, compact, efficient, low vibration cryocooler combines proven 1-stage (RS1 or RP1) and 2-stage (RSP2) cold-head architectures with an inventive set of warm-end mechanisms into a single cooler module, allowing the moving mechanisms for the compressor and the Stirling displacer to be consolidated onto a common axis and in a common working volume. The CI cryocooler is a significant departure from the current Stirling cryocoolers in which the compressor mechanisms are remote from the Stirling displacer mechanism. Placing all of the mechanisms in a single volume and on a single axis provides benefits in terms of package size (30% reduction), mass (30% reduction), thermodynamic efficiency (>20% improvement) and exported vibration performance (≤25 mN peak in all three orthogonal axes at frequencies from 1 to 500 Hz). The main benefit of axial symmetry is that proven balancing

Microscopic analysis of irradiated AGR-1 coated particle fuel compacts

Energy Technology Data Exchange (ETDEWEB)

Ploger, Scott A., E-mail: scott.ploger@inl.gov [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3855 (United States); Demkowicz, Paul A. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3855 (United States); Hunn, John D.; Kehn, Jay S. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6093 (United States)

2014-05-01

The AGR-1 experiment involved irradiation of 72 TRISO-coated particle fuel compacts to a peak compact-average burnup of 19.5% FIMA with no in-pile failures observed out of 3 × 10{sup 5} total particles. Irradiated AGR-1 fuel compacts have been cross-sectioned and analyzed with optical microscopy to characterize kernel, buffer, and coating behavior. Six compacts have been examined, spanning a range of irradiation conditions (burnup, fast fluence, and irradiation temperature) and including all four TRISO coating variations irradiated in the AGR-1 experiment. The cylindrical specimens were sectioned both transversely and longitudinally, then polished to expose from 36 to 79 individual particles near midplane on each mount. The analysis focused primarily on kernel swelling and porosity, buffer densification and fracturing, buffer–IPyC debonding, and fractures in the IPyC and SiC layers. Characteristic morphologies have been identified, 981 particles have been classified, and spatial distributions of particle types have been mapped. No significant spatial patterns were discovered in these cross sections. However, some trends were found between morphological types and certain behavioral aspects. Buffer fractures were found in 23% of the particles, and these fractures often resulted in unconstrained kernel protrusion into the open cavities. Fractured buffers and buffers that stayed bonded to IPyC layers appear related to larger pore size in kernels. Buffer–IPyC interface integrity evidently factored into initiation of rare IPyC fractures. Fractures through part of the SiC layer were found in only four classified particles, all in conjunction with IPyC–SiC debonding. Compiled results suggest that the deliberate coating fabrication variations influenced the frequencies of IPyC fractures and IPyC–SiC debonds.

Final Report on Two-Stage Fast Spectrum Fuel Cycle Options

International Nuclear Information System (INIS)

Yang, Won Sik; Lin, C. S.; Hader, J. S.; Park, T. K.; Deng, P.; Yang, G.; Jung, Y. S.; Kim, T. K.; Stauff, N. E.

2016-01-01

This report presents the performance characteristics of two ''two-stage'' fast spectrum fuel cycle options proposed to enhance uranium resource utilization and to reduce nuclear waste generation. One is a two-stage fast spectrum fuel cycle option of continuous recycle of plutonium (Pu) in a fast reactor (FR) and subsequent burning of minor actinides (MAs) in an accelerator-driven system (ADS). The first stage is a sodium-cooled FR fuel cycle starting with low-enriched uranium (LEU) fuel; at the equilibrium cycle, the FR is operated using the recovered Pu and natural uranium without supporting LEU. Pu and uranium (U) are co-extracted from the discharged fuel and recycled in the first stage, and the recovered MAs are sent to the second stage. The second stage is a sodium-cooled ADS in which MAs are burned in an inert matrix fuel form. The discharged fuel of ADS is reprocessed, and all the recovered heavy metals (HMs) are recycled into the ADS. The other is a two-stage FR/ADS fuel cycle option with MA targets loaded in the FR. The recovered MAs are not directly sent to ADS, but partially incinerated in the FR in order to reduce the amount of MAs to be sent to the ADS. This is a heterogeneous recycling option of transuranic (TRU) elements

Compact Process Development at Babcock & Wilcox

Energy Technology Data Exchange (ETDEWEB)

Eric Shaber; Jeffrey Phillips

2012-03-01

Multiple process approaches have been used historically to manufacture cylindrical nuclear fuel compacts. Scale-up of fuel compacting was required for the Next Generation Nuclear Plant (NGNP) project to achieve an economically viable automated production process capable of providing a minimum of 10 compacts/minute with high production yields. In addition, the scale-up effort was required to achieve matrix density equivalent to baseline historical production processes, and allow compacting at fuel packing fractions up to 46% by volume. The scale-up approach of jet milling, fluid-bed overcoating, and hot-press compacting adopted in the U.S. Advanced Gas Reactor (AGR) Fuel Development Program involves significant paradigm shifts to capitalize on distinct advantages in simplicity, yield, and elimination of mixed waste. A series of compaction trials have been completed to optimize compaction conditions of time, temperature, and forming pressure using natural uranium oxycarbide (NUCO) fuel at packing fractions exceeding 46% by volume. Results from these trials are included. The scale-up effort is nearing completion with the process installed and operable using nuclear fuel materials. Final process testing is in progress to certify the process for manufacture of qualification test fuel compacts in 2012.

Final Report on Two-Stage Fast Spectrum Fuel Cycle Options

Energy Technology Data Exchange (ETDEWEB)

Yang, Won Sik [Purdue Univ., West Lafayette, IN (United States); Lin, C. S. [Purdue Univ., West Lafayette, IN (United States); Hader, J. S. [Purdue Univ., West Lafayette, IN (United States); Park, T. K. [Purdue Univ., West Lafayette, IN (United States); Deng, P. [Purdue Univ., West Lafayette, IN (United States); Yang, G. [Purdue Univ., West Lafayette, IN (United States); Jung, Y. S. [Purdue Univ., West Lafayette, IN (United States); Kim, T. K. [Argonne National Lab. (ANL), Argonne, IL (United States); Stauff, N. E. [Argonne National Lab. (ANL), Argonne, IL (United States)

2016-01-30

This report presents the performance characteristics of two “two-stage” fast spectrum fuel cycle options proposed to enhance uranium resource utilization and to reduce nuclear waste generation. One is a two-stage fast spectrum fuel cycle option of continuous recycle of plutonium (Pu) in a fast reactor (FR) and subsequent burning of minor actinides (MAs) in an accelerator-driven system (ADS). The first stage is a sodium-cooled FR fuel cycle starting with low-enriched uranium (LEU) fuel; at the equilibrium cycle, the FR is operated using the recovered Pu and natural uranium without supporting LEU. Pu and uranium (U) are co-extracted from the discharged fuel and recycled in the first stage, and the recovered MAs are sent to the second stage. The second stage is a sodium-cooled ADS in which MAs are burned in an inert matrix fuel form. The discharged fuel of ADS is reprocessed, and all the recovered heavy metals (HMs) are recycled into the ADS. The other is a two-stage FR/ADS fuel cycle option with MA targets loaded in the FR. The recovered MAs are not directly sent to ADS, but partially incinerated in the FR in order to reduce the amount of MAs to be sent to the ADS. This is a heterogeneous recycling option of transuranic (TRU) elements

Fuel staging tests at the Kymijaervi power plant

International Nuclear Information System (INIS)

Kivelae, M.; Rotter, H.; Virkki, J.

1990-01-01

The aim of this study was to measure nitrogen oxide (NO x ) emissions and find the methods to reduce them in plants using coal and natural gas as fuel. The tests involved were made at the Kymijaervi Power Plant, Lahti, Finland. Coal and natural gas was used alone or mixed. With natural gas when using flue gas recirculation, the NO x emission level dropped from 330 mg/m 3 down to 60 mg/m 3 . A negative side effect was that the flue gas temperature increased. At coal combustion and staged combustion, the flue gas recirculation had no significant effect on the NO x emission level. At coal combustion, the staging of combustion air halved the NO x emission but the combustibles increased strongly. With fuel staging, using coal as main fuel and gas as staging fuel, the NO x emission level was decreased from 340 mg/m 3 to 170 mg/m 3 . At the same time the combustibles increased 2 %- units. Also the flue gas temperature increased a little. At the tests, the proportion of natural gas was rather high, one third of the fuel energy input, but it could not be decreased, because the gas flow ratio was already too low to ensure good mixing

Compact reformer for the solid polymer fuel cell policy and best

Energy Technology Data Exchange (ETDEWEB)

Goulding, P.S.; Deegan, M.; Gough, A. [Newcastle University (United Kingdom)

1998-07-01

This report summarises the results of a study investigating the feasibility of the Compact Reformer concept, and examining its design and manufacture. The development and testing of a hybrid reformer and thin coat catalyst systems are described, and details of the modeling of the reactor, and the optimisation and costing of the solid polymer fuel cell are given. (UK)

Compact approach to long-term monitored retrievable storage of spent fuel

International Nuclear Information System (INIS)

Muir, D.W.

1986-01-01

We examine a new approach to monitored retrievable storage (MRS) that is extremely compact in terms of total land use and may offer increased security and reduced environmental impact, relative to current designs. This approach involves embedding the spent fuel assemblies in monolithic blocks of metallic aluminum. While this would clearly require increased effort in the spent-fuel packaging phase, it would offer in return the above-mentioned environmental advantages, plus the option of easily extending the surface-storage time scale from several years to several decades if a need for longer storage times should arise in the future

Development of a compact, fiber-coupled, six degree-of-freedom measurement system for precision linear stage metrology

International Nuclear Information System (INIS)

Yu, Xiangzhi; Gillmer, Steven R.; Woody, Shane C.; Ellis, Jonathan D.

2016-01-01

A compact, fiber-coupled, six degree-of-freedom measurement system which enables fast, accurate calibration, and error mapping of precision linear stages is presented. The novel design has the advantages of simplicity, compactness, and relatively low cost. This proposed sensor can simultaneously measure displacement, two straightness errors, and changes in pitch, yaw, and roll using a single optical beam traveling between the measurement system and a small target. The optical configuration of the system and the working principle for all degrees-of-freedom are presented along with the influence and compensation of crosstalk motions in roll and straightness measurements. Several comparison experiments are conducted to investigate the feasibility and performance of the proposed system in each degree-of-freedom independently. Comparison experiments to a commercial interferometer demonstrate error standard deviations of 0.33 μm in straightness, 0.14 μrad in pitch, 0.44 μradin yaw, and 45.8 μrad in roll.

Development of a compact, fiber-coupled, six degree-of-freedom measurement system for precision linear stage metrology

Energy Technology Data Exchange (ETDEWEB)

Yu, Xiangzhi, E-mail: xiangzhi.yu@rochester.edu; Gillmer, Steven R. [Department of Mechanical Engineering, University of Rochester, Rochester, New York 14627 (United States); Woody, Shane C. [InSituTec Incorporated, 7140 Weddington Road, Concord, North Carolina 28027 (United States); Ellis, Jonathan D. [Department of Mechanical Engineering, University of Rochester, Rochester, New York 14627 (United States); The Institute of Optics, University of Rochester, Rochester, New York 14627 (United States)

2016-06-15

A compact, fiber-coupled, six degree-of-freedom measurement system which enables fast, accurate calibration, and error mapping of precision linear stages is presented. The novel design has the advantages of simplicity, compactness, and relatively low cost. This proposed sensor can simultaneously measure displacement, two straightness errors, and changes in pitch, yaw, and roll using a single optical beam traveling between the measurement system and a small target. The optical configuration of the system and the working principle for all degrees-of-freedom are presented along with the influence and compensation of crosstalk motions in roll and straightness measurements. Several comparison experiments are conducted to investigate the feasibility and performance of the proposed system in each degree-of-freedom independently. Comparison experiments to a commercial interferometer demonstrate error standard deviations of 0.33 μm in straightness, 0.14 μrad in pitch, 0.44 μradin yaw, and 45.8 μrad in roll.

Dual fuel gradients in uranium silicide plates

Energy Technology Data Exchange (ETDEWEB)

Pace, B.W. [Babock and Wilcox, Lynchburg, VA (United States)

1997-08-01

Babcock & Wilcox has been able to achieve dual gradient plates with good repeatability in small lots of U{sub 3}Si{sub 2} plates. Improvements in homogeneity and other processing parameters and techniques have allowed the development of contoured fuel within the cladding. The most difficult obstacles to overcome have been the ability to evaluate the bidirectional fuel loadings in comparison to the perfect loading model and the different methods of instilling the gradients in the early compact stage. The overriding conclusion is that to control the contour of the fuel, a known relationship between the compact, the frames and final core gradient must exist. Therefore, further development in the creation and control of dual gradients in fuel plates will involve arriving at a plausible gradient requirement and building the correct model between the compact configuration and the final contoured loading requirements.

Development of hull compaction system for nuclear recycle facility

International Nuclear Information System (INIS)

Manole, A.A.; Karkhanis, P.P.; Agarwal, Kailash; Basu, Sekhar

2013-01-01

India has adopted closed fuel cycle strategy for efficient management of available resources to meet long term energy requirements. Nuclear Recycle Facility (NRF) provides a vital link in three-stage Indian nuclear power programme. In a NRF for PHWR fuel cycle, reprocessing of spent fuel bundles from PHWRs is carried out using a chop-leach process where the spent fuel bundles are chopped into small pieces using a spent fuel chopper and the contents inside the zircaloy clad are dissolved using concentric nitric acid. This process generates empty zircaloy shells called 'hulls'. The present practice followed for management of hulls is to transfer them into SS drums and store these drums in underground RCC tile holes at a Waste Management Facility (WMF). This waste needs to be stored in an engineered WMF for at least 30-60 years before transferred to a final repository. The storage volumes required for this hull waste will keep increasing as the reprocessing capacity is being enhanced multi-folds. Compaction of hull waste has been employed internationally to reduce the volume required for storage. Hence indigenous development of hull compaction system was initiated by NRB to meet the future requirements. This is being achieved through a set of experiments and analysis with the available resources within the country. This paper describes the process of compaction, conceptualization of the system and benefits accrued from it. (author)

Raytheon's next generation compact inline cryocooler architecture

Energy Technology Data Exchange (ETDEWEB)

Schaefer, B. R.; Bellis, L.; Ellis, M. J.; Conrad, T. [Raytheon Space and Airborne Systems, 2000 E. El Segundo Blvd., El Segundo, CA 90245 (United States)

2014-01-29

Since the 1970s, Raytheon has developed, built, tested and integrated high performance cryocoolers. Our versatile designs for single and multi-stage cryocoolers provide reliable operation for temperatures from 10 to 200 Kelvin with power levels ranging from 50 W to nearly 600 W. These advanced cryocoolers incorporate clearance seals, flexure suspensions, hermetic housings and dynamic balancing to provide long service life and reliable operation in all relevant environments. Today, sensors face a multitude of cryocooler integration challenges such as exported disturbance, efficiency, scalability, maturity, and cost. As a result, cryocooler selection is application dependent, oftentimes requiring extensive trade studies to determine the most suitable architecture. To optimally meet the needs of next generation passive IR sensors, the Compact Inline Raytheon Stirling 1-Stage (CI-RS1), Compact Inline Raytheon Single Stage Pulse Tube (CI-RP1) and Compact Inline Raytheon Hybrid Stirling/Pulse Tube 2-Stage (CI-RSP2) cryocoolers are being developed to satisfy this suite of requirements. This lightweight, compact, efficient, low vibration cryocooler combines proven 1-stage (RS1 or RP1) and 2-stage (RSP2) cold-head architectures with an inventive set of warm-end mechanisms into a single cooler module, allowing the moving mechanisms for the compressor and the Stirling displacer to be consolidated onto a common axis and in a common working volume. The CI cryocooler is a significant departure from the current Stirling cryocoolers in which the compressor mechanisms are remote from the Stirling displacer mechanism. Placing all of the mechanisms in a single volume and on a single axis provides benefits in terms of package size (30% reduction), mass (30% reduction), thermodynamic efficiency (>20% improvement) and exported vibration performance (≤25 mN peak in all three orthogonal axes at frequencies from 1 to 500 Hz). The main benefit of axial symmetry is that proven balancing

Fuel Accident Condition Simulator (FACS) Furnace for Post-Irradiation Heating Tests of VHTR Fuel Compacts

Energy Technology Data Exchange (ETDEWEB)

Paul A Demkowicz; Paul Demkowicz; David V Laug

2010-10-01

Abstract –Fuel irradiation testing and post-irradiation examination are currently in progress as part of the Next Generation Nuclear Plant Fuels Development and Qualification Program. The PIE campaign will include extensive accident testing of irradiated very high temperature reactor fuel compacts to verify fission product retention characteristics at high temperatures. This work will be carried out at both the Idaho National Laboratory (INL) and the Oak Ridge National Laboratory, beginning with accident tests on irradiated fuel from the AGR-1 experiment in 2010. A new furnace system has been designed, built, and tested at INL to perform high temperature accident tests. The Fuel Accident Condition Simulator furnace system is designed to heat fuel specimens at temperatures up to 2000°C in helium while monitoring the release of volatile fission metals (e.g. Cs, Ag, Sr, Eu, and I) and fission gases (Kr, Xe). Fission gases released from the fuel to the sweep gas are monitored in real time using dual cryogenic traps fitted with high purity germanium detectors. Condensable fission products are collected on a plate attached to a water-cooled cold finger that can be exchanged periodically without interrupting the test. Analysis of fission products on the condensation plates involves dry gamma counting followed by chemical analysis of selected isotopes. This paper will describe design and operational details of the Fuel Accident Condition Simulator (FACS) furnace system, as well as preliminary system calibration results.

Compact fuel storage rack for fuel pools

International Nuclear Information System (INIS)

Parras, F.; Louvat, J.P.

1986-01-01

ETS LEMER and FRAMATOME propose a new compact storage rack. This rack permits a considerable increase of the storage capacity of cooling pools. A short description of the structure and the components is presented, to propose racks that are: . Inalterable, . Compact, . Insensitive to earthquakes. Installation in pools already in operation is simplified by their light structure and the bearing device [fr

Irradiation-induced creep in fuel compacts for high-temperature reactor applications

Energy Technology Data Exchange (ETDEWEB)

Veringa, H; Blackstone, R [Stichting Energieonderzoek Centrum Nederland, Petten; Loelgen, R

1977-01-01

Restrained shrinkage experiments at neutron fluences up to 3 x 10/sup 21/ n cm/sup -2/ DNE in the temperature range 600 to 1200/sup 0/C were performed on three different dummy coated-particle fuel compacts in the high-flux reactor at Petten. The data were evaluated to obtain the steady-state radiation creep coefficient of the compacts. It was found that, for the materials investigated, the creep coefficient is temperature dependent, but no clear relationship with Young's modulus could be established. Under certain conditions this irradiation-induced plasticity influences the elastic properties, with the concomitant increase of the creep coefficient. This effect coincides with the formation and further opening up of cracks due to stresses caused by irradiation-induced shrinkage of matrix material.

Irradiation-induced creep in fuel compacts for high-temperature reactor applications

International Nuclear Information System (INIS)

Veringa, H.; Blackstone, R.; Loelgen, R.

1977-01-01

Restrained shrinkage experiments at neutron fluences up to 3 x 10 21 n cm -2 DNE in the temperature range 600 to 1200 0 C were performed on three different dummy coated-particle fuel compacts in the high-flux reactor at Petten. The data were evaluated to obtain the steady-state radiation creep coefficient of the compacts. It was found that, for the materials investigated, the creep coefficient is temperature dependent, but no clear relationship with Young's modulus could be established. Under certain conditions this irradiation-induced plasticity influences the elastic properties, with the concomitant increase of the creep coefficient. This effect coincides with the formation and further opening up of cracks due to stresses caused by irradiation-induced shrinkage of matrix material. (author)

Optimal dual-fuel propulsion for minimum inert weight or minimum fuel cost

Science.gov (United States)

Martin, J. A.

1973-01-01

An analytical investigation of single-stage vehicles with multiple propulsion phases has been conducted with the phasing optimized to minimize a general cost function. Some results are presented for linearized sizing relationships which indicate that single-stage-to-orbit, dual-fuel rocket vehicles can have lower inert weight than similar single-fuel rocket vehicles and that the advantage of dual-fuel vehicles can be increased if a dual-fuel engine is developed. The results also indicate that the optimum split can vary considerably with the choice of cost function to be minimized.

Compact approach to monitored retrievable storage of spent fuel

International Nuclear Information System (INIS)

Muir, D.W.

1984-09-01

Recent federal waste-management legislation has raised national interest in monitored retrievable storage (MRS) of unprocessed spent fuel from civilian nuclear power plants. We have reviewed the current MRS design approaches, and we have examined an alternative concept that is extremely compact in terms of total land use. This approach may offer substantial advantages in the areas of monitoring and in safeguards against theft, as well as in reducing the chances of groundwater contamination. Total facility costs are roughly estimated and found to be generally competitive with other MRS concepts. 4 references, 3 figures, 3 tables

Compact Design of 10 kW Proton Exchange Membrane Fuel Cell Stack Systems with Microcontroller Units

Directory of Open Access Journals (Sweden)

Hsiaokang Ma

2014-04-01

Full Text Available In this study, fuel, oxidant supply and cooling systems with microcontroller units (MCU are developed in a compact design to fit two 5 kW proton exchange membrane fuel cell (PEMFC stacks. At the initial stage, the testing facility of the system has a large volume (2.0 m × 2.0 m × 1.5 m with a longer pipeline and excessive control sensors for safe testing. After recognizing the performance and stability of stack, the system is redesigned to fit in a limited space (0.4 m × 0.5 m × 0.8 m. Furthermore, the stack performance is studied under different hydrogen recycling modes. Then, two similar 5 kW stacks are directly coupled with diodes to obtain a higher power output and safe operation. The result shows that the efficiency of the 5 kW stack is 43.46% with a purge period of 2 min with hydrogen recycling and that the hydrogen utilization rate µf is 66.31%. In addition, the maximum power output of the twin-coupled module (a power module with two stacks in electrical cascade/parallel arrangement is 9.52 kW.

FRM-II project status and safety of its compact fuel element

International Nuclear Information System (INIS)

Nuding, M.; Rottmann, M.; Axmann, A.; Boening, K.

2000-01-01

The construction of the new research reactor FRM-II is close to completion and the nuclear start-up is scheduled to begin in January 2001. This contribution provides an overview on the concept of the facility and the safety features of the reactor. It also describes some of the tests performed during the licensing procedure of the compact fuel element and their results. At the end a short status report is given. (author)

FRM-II project status and safety of its compact fuel element

Energy Technology Data Exchange (ETDEWEB)

Nuding, M.; Rottmann, M.; Axmann, A.; Boening, K. [Technical University of Munich, D-85747 Garching (Germany)

2000-07-01

The construction of the new research reactor FRM-II is close to completion and the nuclear start-up is scheduled to begin in January 2001. This contribution provides an overview on the concept of the facility and the safety features of the reactor. It also describes some of the tests performed during the licensing procedure of the compact fuel element and their results. At the end a short status report is given. (author)

Nitrogen Chemistry During Burnout in Fuel-Staged Combustion

DEFF Research Database (Denmark)

Kristensen, Per Gravers; Glarborg, Peter; Dam-Johansen, Kim

1996-01-01

A parametric study involving flow reactor experiments and chemical kinetic modeling is presented for the burnout zone in fuel-staging (reburning). The results provide guidelines for optimizing the reburn process and provide a test basis for verifying kinetic models for nitrogen chemistry at tempe......A parametric study involving flow reactor experiments and chemical kinetic modeling is presented for the burnout zone in fuel-staging (reburning). The results provide guidelines for optimizing the reburn process and provide a test basis for verifying kinetic models for nitrogen chemistry...

Designing a miniaturised heated stage for in situ optical measurements of solid oxide fuel cell electrode surfaces, and probing the oxidation of solid oxide fuel cell anodes using in situ Raman spectroscopy

KAUST Repository

Brightman, E.; Maher, R.; Offer, G. J.; Duboviks, V.; Heck, C.; Cohen, L. F.; Brandon, N. P.

2012-01-01

A novel miniaturised heated stage for in operando optical measurements on solid oxide fuel cell electrode surfaces is described. The design combines the advantages of previously reported designs, namely, (i) fully controllable dual atmosphere operation enabling fuel cell pellets to be tested in operando with either electrode in any atmosphere being the focus of study, and (ii) combined electrochemical measurements with optical spectroscopy measurements with the potential for highly detailed study of electrochemical processes; with the following advances, (iii) integrated fitting for mounting on a mapping stage enabling 2-D spatial characterisation of the surface, (iv) a compact profile that is externally cooled, enabling operation on an existing microscope without the need for specialized lenses, (v) the ability to cool very rapidly, from 600 °C to 300 °C in less than 5 min without damaging the experimental apparatus, and (vi) the ability to accommodate a range of pellet sizes and thicknesses. © 2012 American Institute of Physics.

Design considerations for single-stage and two-stage pneumatic pellet injectors

International Nuclear Information System (INIS)

Gouge, M.J.; Combs, S.K.; Fisher, P.W.; Milora, S.L.

1988-09-01

Performance of single-stage pneumatic pellet injectors is compared with several models for one-dimensional, compressible fluid flow. Agreement is quite good for models that reflect actual breech chamber geometry and incorporate nonideal effects such as gas friction. Several methods of improving the performance of single-stage pneumatic pellet injectors in the near term are outlined. The design and performance of two-stage pneumatic pellet injectors are discussed, and initial data from the two-stage pneumatic pellet injector test facility at Oak Ridge National Laboratory are presented. Finally, a concept for a repeating two-stage pneumatic pellet injector is described. 27 refs., 8 figs., 3 tabs

The irradiation induced creep in fuel compact materials for H.T.R. applications

International Nuclear Information System (INIS)

Veringa, H.; Blackstone, R.; Loelgen, R.

1976-01-01

Restrained shrinkage experiments up to 3 x 10 21 ncm -2 (DNE) in the temperature range of 600-1,200 0 C on three different dummy coated particle fuel compact materials were performed in the High Flux Reactor at Petten, the Netherlands. The data were evaluated to obtain the steady state irradiation creep coefficient of the compacts. It was found that for the materials investigated, the creep coefficient is temperature-dependent, but no clear relationship to the Young's modulus could be established. Under certain conditions, this irradiation-induced plasticity influences the elastic properties, while also the creep coefficient increases. This effect coincides with the formation and further opening of cracks due to stresses caused by irradiation shrinkage of the matrix material. (orig.) [de

Compact high-flux two-stage solar collectors based on tailored edge-ray concentrators

Science.gov (United States)

Friedman, Robert P.; Gordon, Jeffrey M.; Ries, Harald

1995-08-01

Using the recently-invented tailored edge-ray concentrator (TERC) approach for the design of compact two-stage high-flux solar collectors--a focusing primary reflector and a nonimaging TERC secondary reflector--we present: 1) a new primary reflector shape based on the TERC approach and a secondary TERC tailored to its particular flux map, such that more compact concentrators emerge at flux concentration levels in excess of 90% of the thermodynamic limit; and 2) calculations and raytrace simulations result which demonstrate the V-cone approximations to a wide variety of TERCs attain the concentration of the TERC to within a few percent, and hence represent practical secondary concentrators that may be superior to corresponding compound parabolic concentrator or trumpet secondaries.

May compact storage facilities be licensed

International Nuclear Information System (INIS)

Gleim, A.; Winter, G.

1980-01-01

The authors examine as potential statements fo fact for licensing so-called compact storage facilities for spent fuel elements Sec. 6 to 9c of the German Atomic Energy Act and Sec. 4 of the German Radiation Protection Ordinance. They find that none of these provisions were applicable to compact stroage facilities. In particular, the storage of spent fuel elements was no storage of nuclear fuels licensable under Sec. 6 of the Atomic Energy Act, because Sec. 6 did not cover spent fuel elements. Also in the other wording of the Atomic Energy Act there was no provision, which could be used as a statement of fact for licensing compact storage facilities. Such facilities could not be licensed and, for that reason, were not permitted. (IVR) [de

TRISO fuel thermal simulations in the LS-VHTR

Energy Technology Data Exchange (ETDEWEB)

Ramos, Mario C.; Scari, Maria E.; Costa, Antonella L.; Pereira, Claubia; Veloso, Maria A.F., E-mail: marc5663@gmail.com, E-mail: melizabethscari@yahoo.com, E-mail: antonella@nuclear.ufmg.br, E-mail: claubia@nuclear.ufmg.br, E-mail: dora@nuclear.ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Instituto Nacional de Ciência e Tecnologia de Reatores Nucleares Inovadores/CNPq (Brazil)

2017-07-01

The liquid-salt-cooled very high-temperature reactor (LS-VHTR) is a reactor that presents very good characteristics in terms of energy production and safety aspects. It uses as fuel the TRISO particles immersed in a graphite matrix with a cylindrical shape called fuel compact, as moderator graphite and as coolant liquid salt Li{sub 2}BeF{sub 4} called Flibe. This work evaluates the thermal hydraulic performance of the heat removal system and the reactor core by performing different simplifications to represent the reactor core and the fuel compact under steady-state conditions, starting the modeling from a single fuel element, until complete the studies with the entire core model developed in the RELAP5-3D code. Two models were considered for representation of the fuel compact, homogeneous and non-homogeneous models, as well as different geometries of the heat structures was considered. The aim to develop several models was to compare the thermal hydraulic characteristics resulting from the construction of a more economical and less discretized model with much more refined models that can lead to more complexes analyzes to representing TRISO effect particles in the fuel compact. The different results found, mainly, for the core temperature distributions are presented and discussed. (author)

Failure mechanisms for compacted uranium oxide fuel cores

International Nuclear Information System (INIS)

Berghaus, D.G.; Peacock, H.B.

1980-01-01

Tension, compression, and shear tests were performed on test specimens of aluminum-clad, compacted powder fuel cores to determine failure mechanisms of the core material. The core, which consists of 70% uranium oxide in an aluminum matrix, frequently fails during post-extrusion drawing. Tests were conducted to various strain levels up to failure of the core. Sections were made of tested specimens to microscopically study initiation of failure. Two failure modes wee observed. Tensile failure mode is initiated by prior tensile failure of uranium oxide particles with the separation path strongly influenced by the arrangement of particles. Delamination mode consists of the separation of laminae formed during extrusion of tubes. Separation proceeds from fine cracks formed parallel to the laminae. Tensile failure mode was experienced in tension and shear tests. Delamination mode was produced in compression tests

A method for determining optimum phasing of a multiphase propulsion system for a single-stage vehicle with linearized inert weight

Science.gov (United States)

Martin, J. A.

1974-01-01

A general analytical treatment is presented of a single-stage vehicle with multiple propulsion phases. A closed-form solution for the cost and for the performance and a derivation of the optimal phasing of the propulsion are included. Linearized variations in the inert weight elements are included, and the function to be minimized can be selected. The derivation of optimal phasing results in a set of nonlinear algebraic equations for optimal fuel volumes, for which a solution method is outlined. Three specific example cases are analyzed: minimum gross lift-off weight, minimum inert weight, and a minimized general function for a two-phase vehicle. The results for the two-phase vehicle are applied to the dual-fuel rocket. Comparisons with single-fuel vehicles indicate that dual-fuel vehicles can have lower inert weight either by development of a dual-fuel engine or by parallel burning of separate engines from lift-off.

Coupled 3D neutronic and thermohydraulic calculations for a compact fuel element with disperse UMo fuel at FRM II

International Nuclear Information System (INIS)

Breitkreutz, H.; Roehrmoser, A.; Petry, W.

2010-01-01

The newly developed X 2 program system is intended to be used for high-detail 3D calculations on compact research reactor cores. Using this system, the efforts to calculate scenarios for a new fuel element for FRM II using disperse UMo (8wt% Mo, 50% enrichment) are continued. By now, a radial symmetric core model with averaged built-in components for the D 2 O tank is used. Two different scenarios are compared: The minimum fuel density of 7.5 g U/cm 3 and 8.0 g U/cm 3 with 60 days cycle length. In addition, two 'flux loss compensating' scenarios based on 8.0 g U/cm 3 with 10% higher power/longer reactor cycles are regarded. (author)

High Power Compact Single-Frequency Volume Bragg Er-Doped Fiber Laser, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The purpose of this NASA SBIR Phase I proposal is to develop the prototype of a compact single-frequency mode one longitudinal and one transverse mode laser...

Concept of safe tank-type water cooled and moderated reactor with HTGR microparticle fuel compacts

International Nuclear Information System (INIS)

Gol'tsev, A.O.; Kukharkin, N.E.; Mosevitskij, I.S.; Ponomarev-Stepnoj, N.N.; Popov, S.V.; Udyanskij, Yu.N.; Tsibul'skij, V.F.

1993-01-01

Concept of safe tank-type water-cooled and moderated reactor on the basis of HTGR fuel microparticles which enable to avoid environment contamination with radioactive products under severe accidents, is proposed. Results of neutron-physical and thermal-physical studies of water cooled and moderated reactor with HTGR microparticle compacts are presented. Characteristics of two reactors with thermal power of 500 and 1500 MW are indicated within the concept frames. The reactor behaviour under severe accident connected with complete loss of water coolant is considered. It is shown that under such an accident the fission products release from fuel microparticles does not occur

Role of wall heat transfer and other system variables on fuel compaction and recriticality

International Nuclear Information System (INIS)

Dhir, V.K.; Castle, J.N.; Catton, I.; Kastenberg, W.E.; Doshi, J.B.

1976-01-01

The assessment of the molten fuel gaining recriticality after a hypothetical core disruptive accident in a fast reactor is an important safety consideration. Recriticality of the disrupted core can be envisioned to occur, if the fuel rearranges itself into a denser configuration either due to gravity slumping of the molten fuel or due to pressure or heat transfer driven compaction of the earlier dispersed fuel. In this paper the role played by wall heat transfer, internal radiation and the bottle pressure on the physical state of the molten fuel pool is discussed. It is suggested that in the absence of a solid crust the heat transfer process from the molten fuel to the surrounding steel will be very efficient because of melting and buoyancy driven removal of less dense steel through the pool of heavier UO 2 . The internal radiation at the high fuel temperature significantly increase the effective thermal conductivity of the molten fuel and lead to increased heat transfer in situations where a solid crust of UO 2 exists between molten UO 2 and molten steel. IN a boiled-up bottled pool, the pool pressure is shown to increase very rapidly with time and thus necessitate higher fission heating of the fuel to maintain it in a certain boiled up state. Finally, the results of the above discussion are applied to study the recriticality of a fuel pool formed during a hypothetical core disrupted accident in a fast reactor

A compact PE memory for vision chips

Science.gov (United States)

Cong, Shi; Zhe, Chen; Jie, Yang; Nanjian, Wu; Zhihua, Wang

2014-09-01

This paper presents a novel compact memory in the processing element (PE) for single-instruction multiple-data (SIMD) vision chips. The PE memory is constructed with 8 × 8 register cells, where one latch in the slave stage is shared by eight latches in the master stage. The memory supports simultaneous read and write on the same address in one clock cycle. Its compact area of 14.33 μm2/bit promises a higher integration level of the processor. A prototype chip with a 64 × 64 PE array is fabricated in a UMC 0.18 μm CMOS technology. Five types of the PE memory cell structure are designed and compared. The testing results demonstrate that the proposed PE memory architecture well satisfies the requirement of the vision chip in high-speed real-time vision applications, such as 1000 fps edge extraction.

A compact PE memory for vision chips

International Nuclear Information System (INIS)

Shi Cong; Chen Zhe; Yang Jie; Wu Nanjian; Wang Zhihua

2014-01-01

This paper presents a novel compact memory in the processing element (PE) for single-instruction multiple-data (SIMD) vision chips. The PE memory is constructed with 8 × 8 register cells, where one latch in the slave stage is shared by eight latches in the master stage. The memory supports simultaneous read and write on the same address in one clock cycle. Its compact area of 14.33 μm 2 /bit promises a higher integration level of the processor. A prototype chip with a 64 × 64 PE array is fabricated in a UMC 0.18 μm CMOS technology. Five types of the PE memory cell structure are designed and compared. The testing results demonstrate that the proposed PE memory architecture well satisfies the requirement of the vision chip in high-speed real-time vision applications, such as 1000 fps edge extraction. (semiconductor integrated circuits)

Comparisons of single-stage and two-stage approaches to genomic selection.

Science.gov (United States)

Schulz-Streeck, Torben; Ogutu, Joseph O; Piepho, Hans-Peter

2013-01-01

Genomic selection (GS) is a method for predicting breeding values of plants or animals using many molecular markers that is commonly implemented in two stages. In plant breeding the first stage usually involves computation of adjusted means for genotypes which are then used to predict genomic breeding values in the second stage. We compared two classical stage-wise approaches, which either ignore or approximate correlations among the means by a diagonal matrix, and a new method, to a single-stage analysis for GS using ridge regression best linear unbiased prediction (RR-BLUP). The new stage-wise method rotates (orthogonalizes) the adjusted means from the first stage before submitting them to the second stage. This makes the errors approximately independently and identically normally distributed, which is a prerequisite for many procedures that are potentially useful for GS such as machine learning methods (e.g. boosting) and regularized regression methods (e.g. lasso). This is illustrated in this paper using componentwise boosting. The componentwise boosting method minimizes squared error loss using least squares and iteratively and automatically selects markers that are most predictive of genomic breeding values. Results are compared with those of RR-BLUP using fivefold cross-validation. The new stage-wise approach with rotated means was slightly more similar to the single-stage analysis than the classical two-stage approaches based on non-rotated means for two unbalanced datasets. This suggests that rotation is a worthwhile pre-processing step in GS for the two-stage approaches for unbalanced datasets. Moreover, the predictive accuracy of stage-wise RR-BLUP was higher (5.0-6.1%) than that of componentwise boosting.

Compact teleoperated laparoendoscopic single-site robotic surgical system: Kinematics, control, and operation.

Science.gov (United States)

Isaac-Lowry, Oran Jacob; Okamoto, Steele; Pedram, Sahba Aghajani; Woo, Russell; Berkelman, Peter

2017-12-01

To date a variety of teleoperated surgical robotic systems have been developed to improve a surgeon's ability to perform demanding single-port procedures. However typical large systems are bulky, expensive, and afford limited angular motion, while smaller designs suffer complications arising from limited motion range, speed, and force generation. This work was to develop and validate a simple, compact, low cost single site teleoperated laparoendoscopic surgical robotic system, with demonstrated capability to carry out basic surgical procedures. This system builds upon previous work done at the University of Hawaii at Manoa and includes instrument and endoscope manipulators as well as compact articulated instruments designed to overcome single incision geometry complications. A robotic endoscope holder was used for the base, with an added support frame for teleoperated manipulators and instruments fabricated mostly from 3D printed parts. Kinematics and control methods were formulated for the novel manipulator configuration. Trajectory following results from an optical motion tracker and sample task performance results are presented. Results indicate that the system has successfully met the goal of basic surgical functionality while minimizing physical size, complexity, and cost. Copyright © 2017 John Wiley & Sons, Ltd.

Compact inertial confinement multireactor concepts

International Nuclear Information System (INIS)

Pendergrass, J.H.

1985-01-01

Inertial confinement fusion (ICF) commercial-applications plant-optimum driver pulse repetition rates may exceed reactor pulse-repetition-rate capabilities. Thus, more than one reactor may be required for low-cost production of electric power, process heat, fissionable fuels, etc., in ICF plants. Substantial savings in expensive reactor containment cells and blankets can be realized by placing more than one reactor in a cell and by surrounding more than one reactor cavity with a single blanket system. There are also some potential disadvantages associated with close coupling in compact multicavity blankets and multireactor cells. Tradeoffs associated with several scenarios have been studied

Comparison of single-stage and temperature-phased two-stage anaerobic digestion of oily food waste

International Nuclear Information System (INIS)

Wu, Li-Jie; Kobayashi, Takuro; Li, Yu-You; Xu, Kai-Qin

2015-01-01

Highlights: • A single-stage and two two-stage anaerobic systems were synchronously operated. • Similar methane production 0.44 L/g VS_a_d_d_e_d from oily food waste was achieved. • The first stage of the two-stage process became inefficient due to serious pH drop. • Recycle favored the hythan production in the two-stage digestion. • The conversion of unsaturated fatty acids was enhanced by recycle introduction. - Abstract: Anaerobic digestion is an effective technology to recover energy from oily food waste. A single-stage system and temperature-phased two-stage systems with and without recycle for anaerobic digestion of oily food waste were constructed to compare the operation performances. The synchronous operation indicated the similar ability to produce methane in the three systems, with a methane yield of 0.44 L/g VS_a_d_d_e_d. The pH drop to less than 4.0 in the first stage of two-stage system without recycle resulted in poor hydrolysis, and methane or hydrogen was not produced in this stage. Alkalinity supplement from the second stage of two-stage system with recycle improved pH in the first stage to 5.4. Consequently, 35.3% of the particulate COD in the influent was reduced in the first stage of two-stage system with recycle according to a COD mass balance, and hydrogen was produced with a percentage of 31.7%, accordingly. Similar solids and organic matter were removed in the single-stage system and two-stage system without recycle. More lipid degradation and the conversion of long-chain fatty acids were achieved in the single-stage system. Recycling was proved to be effective in promoting the conversion of unsaturated long-chain fatty acids into saturated fatty acids in the two-stage system.

Combustion of coal gas fuels in a staged combustor

Science.gov (United States)

Rosfjord, T. J.; Mcvey, J. B.; Sederquist, R. A.; Schultz, D. F.

1982-01-01

Gaseous fuels produced from coal resources generally have heating values much lower than natural gas; the low heating value could result in unstable or inefficient combustion. Coal gas fuels may contain ammonia which if oxidized in an uncontrolled manner could result in unacceptable nitrogen oxide exhaust emission levels. Previous investigations indicate that staged, rich-lean combustion represents a desirable approach to achieve stable, efficient, low nitrogen oxide emission operation for coal-derived liquid fuels contaning up to 0.8-wt pct nitrogen. An experimental program was conducted to determine whether this fuel tolerance can be extended to include coal-derived gaseous fuels. The results of tests with three nitrogen-free fuels having heating values of 100, 250, and 350 Btu/scf and a 250 Btu/scf heating value doped to contain 0.7 pct ammonia are presented.

Control of Single-Stage Single-Phase PV inverter

DEFF Research Database (Denmark)

Ciobotaru, Mihai; Teodorescu, Remus; Blaabjerg, Frede

2005-01-01

In this paper the issue of control strategies for single-stage photovoltaic (PV) inverter is addressed. Two different current controllers have been implemented and an experimental comparison between them has been made. A complete control structure for the single-phase PV system is also presented......-forward; - and the grid current controller implemented in two different ways, using the classical proportional integral (PI) and the novel proportional resonant (PR) controllers. The control strategy was tested experimentally on 1.5 kW PV inverter....

Compact gasoline fuel processor for passenger vehicle APU

Science.gov (United States)

Severin, Christopher; Pischinger, Stefan; Ogrzewalla, Jürgen

Due to the increasing demand for electrical power in today's passenger vehicles, and with the requirements regarding fuel consumption and environmental sustainability tightening, a fuel cell-based auxiliary power unit (APU) becomes a promising alternative to the conventional generation of electrical energy via internal combustion engine, generator and battery. It is obvious that the on-board stored fuel has to be used for the fuel cell system, thus, gasoline or diesel has to be reformed on board. This makes the auxiliary power unit a complex integrated system of stack, air supply, fuel processor, electrics as well as heat and water management. Aside from proving the technical feasibility of such a system, the development has to address three major barriers:start-up time, costs, and size/weight of the systems. In this paper a packaging concept for an auxiliary power unit is presented. The main emphasis is placed on the fuel processor, as good packaging of this large subsystem has the strongest impact on overall size. The fuel processor system consists of an autothermal reformer in combination with water-gas shift and selective oxidation stages, based on adiabatic reactors with inter-cooling. The configuration was realized in a laboratory set-up and experimentally investigated. The results gained from this confirm a general suitability for mobile applications. A start-up time of 30 min was measured, while a potential reduction to 10 min seems feasible. An overall fuel processor efficiency of about 77% was measured. On the basis of the know-how gained by the experimental investigation of the laboratory set-up a packaging concept was developed. Using state-of-the-art catalyst and heat exchanger technology, the volumes of these components are fixed. However, the overall volume is higher mainly due to mixing zones and flow ducts, which do not contribute to the chemical or thermal function of the system. Thus, the concept developed mainly focuses on minimization of those

Coupling of the four design stages in the management of nuclear fuel

International Nuclear Information System (INIS)

Marinez R, R. L.

2016-01-01

In this work, the main characteristics of the system to solve the four stages of the nuclear fuel management are presented; the above for boiling water reactors (BWR). The novelty of the system is that a complete solution is obtained in a coupled way; the involved stages are fuel lattice design, fuel assembly design, fuel reload design and control rod pattern design. To do this, in each stage of the process some heuristics techniques are applied, and each stage has its own objective function. The used heuristic techniques are neural network and a hybrid between scatter search and path re linking for fuel lattice design; for fuel assembly design a simple local search was applied and finally, for both fuel reload and control rod pattern designs, the tabu search technique was used. The system have two loops, one external loop and one internal loop, the first one starts with fuel lattice design and concludes with control rod pattern design; on the other hand, the internal loop executes an iterative process between both fuel reload design and control rod pattern designs, to start this loop a seed fuel reload is required, which is obtained applying Haling principle. The internal loop is finished when four iterations were achieved, while the external loop is finished when two iterations were achieved, this number of iterations was fixed due to the great quantity of required computational resources. An 18- months equilibrium cycle was considered to have a reference value to compare against the obtained results with our system, this cycle have two fuel fresh batches with the same average uranium enrichment, but different gadolinia content. The above cycle achieved a 10,896 Mwd/Tu of energy and was divided into 12 burnup steps. The obtained results show the advantage to solve the complete problem in a coupled way, even though a great quantity of computational resources are used. It is necessary to note that the energy value was not achieved in all cases, only in some

Three-peat NREL Intern Pushes Boundaries of Early-Stage Fuels Research on

Science.gov (United States)

-Stage Fuels Research on Way to Master's Degree January 4, 2018 Woman preparing a fuel evaluation in a . Mission & Programs Awards History Leadership Community Education Center Economic Impact Environment

Hydrogen from methanol for fuel cells in mobile systems: development of a compact reformer

Energy Technology Data Exchange (ETDEWEB)

Hoehlein, B [Forschungszentrum Juelich GmbH (Germany); Boe, M [H. Topsoee A/S, Lyngby (Denmark); Boegild-Hansen, J [H. Topsoee A/S, Lyngby (Denmark); Broeckerhoff, P [Forschungszentrum Juelich GmbH (Germany); Colsman, G [Forschungszentrum Juelich GmbH (Germany); Emonts, B [Forschungszentrum Juelich GmbH (Germany); Menzer, R [Forschungszentrum Juelich GmbH (Germany); Riedel, E

1996-07-01

On-board generation of hydrogen from methanol with a reformer in connection with the use of a proton-exchange membrane fuel cell (PEMFC) is an attractive option for a passenger car drive. Special considerations are required to obtain low weight and volume. Furthermore, the PEMFC of today cannot tolerate more than 10 ppm of carbon monoxide in the fuel. Therefore a gas conditioning step is needed after the methanol reformer. Our main research activities focus on the conceptual design of a drive system for a passenger car with methanol reformer and PEMFC: Engineering studies with regard to different aspects of this design including reformer, catalytic burner, gas conditioning, balances of the fuel cycles and basic design of a compact methanol reformer. The work described here was carried out within the framework of a JOULE II project of the European Union (1993-1995). Extensive experimental studies have been carried out at the Forschungszentrum Juelich GmbH (KFA) in Germany and at Haldor Topsoee A/S in Denmark. (orig.)

Design and analysis of a single stage to orbit nuclear thermal rocket reactor engine

Energy Technology Data Exchange (ETDEWEB)

Labib, Satira, E-mail: Satira.Labib@duke-energy.com; King, Jeffrey, E-mail: kingjc@mines.edu

2015-06-15

Graphical abstract: - Highlights: • Three NTR reactors are optimized for the single stage launch of 1–15 MT payloads. • The proposed rocket engines have specific impulses in excess of 700 s. • Reactivity and submersion criticality requirements are satisfied for each reactor. - Abstract: Recent advances in the development of high power density fuel materials have renewed interest in nuclear thermal rockets (NTRs) as a viable propulsion technology for future space exploration. This paper describes the design of three NTR reactor engines designed for the single stage to orbit launch of payloads from 1 to 15 metric tons. Thermal hydraulic and rocket engine analyses indicate that the proposed rocket engines are able to reach specific impulses in excess of 800 s. Neutronics analyses performed using MCNP5 demonstrate that the hot excess reactivity, shutdown margin, and submersion criticality requirements are satisfied for each NTR reactor. The reactors each consist of a 40 cm diameter core packed with hexagonal tungsten cermet fuel elements. The core is surrounded by radial and axial beryllium reflectors and eight boron carbide control drums. The 40 cm long reactor meets the submersion criticality requirements (a shutdown margin of at least $1 subcritical in all submersion scenarios) with no further modifications. The 80 and 120 cm long reactors include small amounts of gadolinium nitride as a spectral shift absorber to keep them subcritical upon submersion in seawater or wet sand following a launch abort.

Design and analysis of a single stage to orbit nuclear thermal rocket reactor engine

International Nuclear Information System (INIS)

Labib, Satira; King, Jeffrey

2015-01-01

Graphical abstract: - Highlights: • Three NTR reactors are optimized for the single stage launch of 1–15 MT payloads. • The proposed rocket engines have specific impulses in excess of 700 s. • Reactivity and submersion criticality requirements are satisfied for each reactor. - Abstract: Recent advances in the development of high power density fuel materials have renewed interest in nuclear thermal rockets (NTRs) as a viable propulsion technology for future space exploration. This paper describes the design of three NTR reactor engines designed for the single stage to orbit launch of payloads from 1 to 15 metric tons. Thermal hydraulic and rocket engine analyses indicate that the proposed rocket engines are able to reach specific impulses in excess of 800 s. Neutronics analyses performed using MCNP5 demonstrate that the hot excess reactivity, shutdown margin, and submersion criticality requirements are satisfied for each NTR reactor. The reactors each consist of a 40 cm diameter core packed with hexagonal tungsten cermet fuel elements. The core is surrounded by radial and axial beryllium reflectors and eight boron carbide control drums. The 40 cm long reactor meets the submersion criticality requirements (a shutdown margin of at least $1 subcritical in all submersion scenarios) with no further modifications. The 80 and 120 cm long reactors include small amounts of gadolinium nitride as a spectral shift absorber to keep them subcritical upon submersion in seawater or wet sand following a launch abort

System-level Reliability Assessment of Power Stage in Fuel Cell Application

DEFF Research Database (Denmark)

Zhou, Dao; Wang, Huai; Blaabjerg, Frede

2016-01-01

reliability. In a case study of a 5 kW fuel cell power stage, the parameter variations of the lifetime model prove that the exponential factor of the junction temperature fluctuation is the most sensitive parameter. Besides, if a 5-out-of-6 redundancy is used, it is concluded both the B10 and the B1 system......High efficient and less pollutant fuel cell stacks are emerging and strong candidates of the power solution used for mobile base stations. In the application of the backup power, the availability and reliability hold the highest priority. This paper considers the reliability metrics from...... the component-level to the system-level for the power stage used in a fuel cell application. It starts with an estimation of the annual accumulated damage for the key power electronic components according to the real mission profile of the fuel cell system. Then, considering the parameter variations in both...

Automated assembling of single fuel cell units for use in a fuel cell stack

Science.gov (United States)

Jalba, C. K.; Muminovic, A.; Barz, C.; Nasui, V.

2017-05-01

The manufacturing of PEMFC stacks (POLYMER ELEKTROLYT MEMBRAN Fuel Cell) is nowadays still done by hand. Over hundreds of identical single components have to be placed accurate together for the construction of a fuel cell stack. Beside logistic problems, higher total costs and disadvantages in weight the high number of components produce a higher statistic interference because of faulty erection or material defects and summation of manufacturing tolerances. The saving of costs is about 20 - 25 %. Furthermore, the total weight of the fuel cells will be reduced because of a new sealing technology. Overall a one minute cycle time has to be aimed per cell at the manufacturing of these single components. The change of the existing sealing concept to a bonded sealing is one of the important requisites to get an automated manufacturing of single cell units. One of the important steps for an automated gluing process is the checking of the glue application by using of an image processing system. After bonding the single fuel cell the sealing and electrical function can be checked, so that only functional and high qualitative cells can get into further manufacturing processes.

MICRO/NANO-STRUCTURAL EXAMINATION AND FISSION PRODUCT IDENTIFICATION IN NEUTRON IRRADIATED AGR-1 TRISO FUEL

Energy Technology Data Exchange (ETDEWEB)

van Rooyen, I. J.; Lillo, T. M.; Wen, H. M.; Hill, C. M.; Holesinger, T. G.; Wu, Y. Q.; Aguiara, J. A.

2016-11-01

Advanced microscopic and microanalysis techniques were developed and applied to study irradiation effects and fission product behavior in selected low-enriched uranium oxide/uranium carbide TRISO-coated particles from fuel compacts in six capsules irradiated to burnups of 11.2 to 19.6% FIMA. Although no TRISO coating failures were detected during the irradiation, the fraction of Ag-110m retained in individual particles often varied considerably within a single compact and at the capsule level. At the capsule level Ag-110m release fractions ranged from 1.2 to 38% and within a single compact, silver release from individual particles often spanned a range that extended from 100% retention to nearly 100% release. In this paper, selected irradiated particles from Baseline, Variant 1 and Variant 3 type fueled TRISO coated particles were examined using Scanning Electron Microscopy, Atom Probe Tomography; Electron Energy Loss Spectroscopy; Precession Electron Diffraction, Transmission Electron Microscopy, Scanning Transmission Electron Microscopy (STEM), High Resolution Electron Microscopy (HRTEM) examinations and Electron Probe Micro-Analyzer. Particle selection in this study allowed for comparison of the fission product distribution with Ag retention, fuel type and irradiation level. Nano sized Ag-containing features were predominantly identified in SiC grain boundaries and/or triple points in contrast with only two sitings of Ag inside a SiC grain in two different compacts (Baseline and Variant 3 fueled compacts). STEM and HRTEM analysis showed evidence of Ag and Pd co-existence in some cases and it was found that fission product precipitates can consist of multiple or single phases. STEM analysis also showed differences in precipitate compositions between Baseline and Variant 3 fuels. A higher density of fission product precipitate clusters were identified in the SiC layer in particles from the Variant 3 compact compared with the Variant 1 compact. Trend analysis shows

Developing Xenopus Embryos Recover by Compacting and Expelling Single-Wall Carbon Nanotubes

Science.gov (United States)

Holt, Brian D.; Shawky, Joseph H.; Dahl, Kris Noel; Davidson, Lance A.; Islam, Mohammad F.

2015-01-01

Single-wall carbon nanotubes are high aspect ratio nanomaterials that are being developed for use in materials, technological and biological applications due to their high mechanical stiffness, optical properties, and chemical inertness. Because of their prevalence, it is inevitable that biological systems will be exposed to nanotubes, yet studies of the effects of nanotubes on developing embryos have been inconclusive and are lacking for single-wall carbon nanotubes exposed to the widely studied model organism Xenopus laevis (African clawed frog). Microinjection of experimental substances into the Xenopus embryo is a standard technique for toxicology studies and cellular lineage tracing. Here we report the surprising finding that superficial (12.5 ± 7.5 μm below the membrane) microinjection of nanotubes dispersed with Pluronic F127 into one-to-two cell Xenopus embryos resulted in the formation and expulsion of compacted, nanotube-filled, punctate masses, at the blastula to mid-gastrula developmental stages, which we call “boluses”. Such expulsion of microinjected materials by Xenopus embryos has not been reported before and is dramatically different from the typical distribution of the materials throughout the progeny of the microinjected cells. Previous studies of microinjections of nanomaterials such as nanodiamonds, quantum dots or spherical nanoparticles report that nanomaterials often induce toxicity and remain localized within the embryos. In contrast, our results demonstrate an active recovery pathway for embryos after exposure to Pluronic F127-coated nanotubes, which we speculate is due to a combined effect of the membrane activity of the dispersing agent, Pluronic F127, and the large aspect ratio of nanotubes. PMID:26153061

Developing Xenopus embryos recover by compacting and expelling single wall carbon nanotubes.

Science.gov (United States)

Holt, Brian D; Shawky, Joseph H; Dahl, Kris Noel; Davidson, Lance A; Islam, Mohammad F

2016-04-01

Single wall carbon nanotubes are high aspect ratio nanomaterials being developed for use in materials, technological and biological applications due to their high mechanical stiffness, optical properties and chemical inertness. Because of their prevalence, it is inevitable that biological systems will be exposed to nanotubes, yet studies of the effects of nanotubes on developing embryos have been inconclusive and are lacking for single wall carbon nanotubes exposed to the widely studied model organism Xenopus laevis (African clawed frog). Microinjection of experimental substances into the Xenopus embryo is a standard technique for toxicology studies and cellular lineage tracing. Here we report the surprising finding that superficial (12.5 ± 7.5 µm below the membrane) microinjection of nanotubes dispersed with Pluronic F127 into one- to two-cell Xenopus embryos resulted in the formation and expulsion of compacted, nanotube-filled, punctate masses, at the blastula to mid-gastrula developmental stages, which we call "boluses." Such expulsion of microinjected materials by Xenopus embryos has not been reported before and is dramatically different from the typical distribution of the materials throughout the progeny of the microinjected cells. Previous studies of microinjections of nanomaterials such as nanodiamonds, quantum dots or spherical nanoparticles report that nanomaterials often induce toxicity and remain localized within the embryos. In contrast, our results demonstrate an active recovery pathway for embryos after exposure to Pluronic F127-coated nanotubes, which we speculate is due to a combined effect of the membrane activity of the dispersing agent, Pluronic F127, and the large aspect ratio of nanotubes. Copyright © 2015 John Wiley & Sons, Ltd.

A Two-stage DC-DC Converter for the Fuel Cell-Supercapacitor Hybrid System

DEFF Research Database (Denmark)

Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.

2009-01-01

A wide input range multi-stage converter is proposed with the fuel cells and supercapacitors as a hybrid system. The front-end two-phase boost converter is used to optimize the output power and to reduce the current ripple of fuel cells. The supercapacitor power module is connected by push...... and designed. A 1kW prototype controlled by TMS320F2808 DSP is built in the lab. Simulation and experimental results confirm the feasibility of the proposed two stage dc-dc converter system.......-pull-forward half bridge (PPFHB) converter with coupled inductors in the second stage to handle the slow transient response of the fuel cells and realize the bidirectional power flow control. Moreover, this cascaded structure simplifies the power management. The control strategy for the whole system is analyzed...

Development of the compaction machine for the production of new shapes of pressed biofuels

Science.gov (United States)

Šooš, Ľubomír; Matúš, Miloš; Beniak, Juraj; Križan, Peter

2018-01-01

Briquettes and especially pellets became the fuel of the 21st century. These are pressed biofuels made from the biomass which have the required heat, shape, size, density and mechanical properties. Today, these pressed biofuels are made in the form of a block, cylinder, n-angle octagonal, either without or with the holes. Several analyses confirm that neither a block, nor the cylinder is the optimal shape for the production of pressed biofuels, both in terms of the production, storage, automated transport in the combustion process and the optimum combustion process. For this reason, we began to analyse different shape, size, density and mechanical properties of briquettes and pellets. In the first part of this article, the biofuel is described from these points of view. The result of this analysis is the new optimized spheroid shape of the pressed biofuels. The goal of the second part of the article is the construction design of a new compacting machine for manufacturing of the optimized shape of the compacted piece. The task is demanding due to the fact that in comparison to the production of cylindrical or square-shaped compacted pieces, the manufacturing of ‘quasi-spherical’ compacted pieces is discontinuous. Furthermore, unlike the standard types of compaction presses which compact the material between the two cylinders, it is necessary to hold the compacted piece for certain time under high pressure and at the high temperature. In this way, the lignin contained in compacted raw material becomes plastic and no further binding material needs to be added. The kinematics of a new compactor was therefore divided into two stages- ‘the stage of compacting’ and ‘the stage of load bearing capacity. This article describes an innovative and patent protected principle of compactor construction. The prototype of a designed machine has already been produced in our department. The first test results of this machine production as described in the conclusion of the

Single-Mode, High Repetition Rate, Compact Ho:YLF Laser for Space-Borne Lidar Applications

Science.gov (United States)

Bai, Yingxin; Yu, Jirong; Wong, Teh-Hwa; Chen, Songsheng; Petros, Mulugeta; Singh, Upendra N.

2014-01-01

A single transverse/longitudinal mode, compact Q-switched Ho:YLF laser has been designed and demonstrated for space-borne lidar applications. The pulse energy is between 34-40 mJ for 100-200 Hz operation. The corresponding peak power is >1 MW.

Compact spent fuel storage at the Atucha I nuclear power plant

International Nuclear Information System (INIS)

Antonaccio, Carlos; Conde, Alberto; Flores, Alexis; Masciotra, Humberto; Sala, Guillermo; Zanni, Pablo

2000-01-01

The object of this report is to verify the possibility to increase the available storage of irradiated fuel assemblies, placed in the spent fuel pools of the Atucha I nuclear power plant. There is intends the realization of structural modifications in the storage bracket-suspension beam (single and double) for the upper and lower level of the four spent fuel pools. With these modifications that increase the storage capacity 25%, would arrive until the year 2014, it dates dear for the limit of the commercial operation of nuclear power plant. The increase of the capacity in function of the permissible stress for the supports of the bracket-suspension beam. They should be carried out 5000 re-accommodations of irradiated fuel assemblies. The task would demand approximately 3 years. (author)

Functioning of blocks of compacted bentonite in a repository for spent nuclear fuels

International Nuclear Information System (INIS)

Boergesson, Lennart; Kalbantner, P.; Sjoeblom, R.

2001-12-01

The main purpose of the presented work is to provide The Swedish Nuclear Fuel and Waste Management Company (SKB) with a proposed set of requirements regarding the functioning of the blocks of compacted bentonite. These blocks are intended to constitute the bentonite envelope which after uptake of water will form the buffer between the canister and the rock. The purpose is also to provide a basis for SKB for their direction of the continued development work for the selection of a reference technology and for creating a quality system for the buffer material. No attempts are made in the report to derive the functional requirements. Instead, such requirements are postulated based on realistic scenarios regarding the chain of processes from excavation - transport - preparation of press powder - compaction - handling and emplacement in the deposition hole. It is the strategy of SKB to use a natural material which after the above-mentioned processes forms a buffer with properties which closely resemble those of the original material. This implies that all process steps must be designed in such a way that the properties of the bentonite do not change to any significant degree with respect to the disposal function. The main results in the report are as follows: A set of functional requirements are compiled and presented. These concord with the different descriptions given on the process steps. The requirements are generic and are assessed to be relatively invariant for various operational requirements and process controls. The process chain comprising excavation of bentonite - transport - preparation of press powder - compaction - handling and emplacement are explained. The presentations of functional requirements and processes are foreseen to constitute a basis for a comparison between uniaxial and isostatic compaction and can be an important basis for SKB's quality work. The development of cracks in the bentonite blocks has been identified as an important aspect for the

Means, methods and performances of the AREVA's HTR compact controls

International Nuclear Information System (INIS)

Banchet, J.; Guillermier, P.; Tisseur, D.; Vitali, M. P.

2008-01-01

In the AREVA's HTR development program, the reactor plant is composed of a prismatic core containing graphite cylindrical fuel elements, called compacts, where TRISO particles are dispersed. Starting from its past compacting process, the latter being revamped through the use of state of the art equipments, CERCA, 100% AREVA NP's subsidiary, was able to recover the quality of past compacts production. The recovered compacting process is composed of the following manufacturing steps: graphite matrix granulation, mix between the obtained granulates and particles, compacting and calcining at low pressure and temperature. To adapt this past process to new manufacturing equipments, non destructive examination tests were carried out to assess the compact quality, the latter being assessed via in house developed equipments and methods at each step of the design of experiments. As for the manufacturing process, past quality control methods were revamped to measure compact dimensional features (diameter, perpendicularity and cone effect), visual aspect, SiC layer failure fraction (via anodic disintegration and burn leach test) and homogeneity via 2D radiography coupled to ceramography. Although meeting quality requirements, 2D radiography method could not provide a quantified specification for compact homogeneity characterization. This limitation yielded the replacement of this past technique by a method based on X-Ray tomography. Development was conducted on this new technique to enable the definition of a criterion to quantify compact homogeneity, as well as to provide information about the distances in between particles. This study also included a comparison between simulated and real compacts to evaluate the accuracy of the technique as well as the influence of particle packing fraction on compact homogeneity. The developed quality control methods and equipments guided the choices of manufacturing parameters adjustments at the development stage and are now applied for

Comminution circuits for compact itabirites

Directory of Open Access Journals (Sweden)

Pedro Ferreira Pinto

Full Text Available Abstract In the beneficiation of compact Itabirites, crushing and grinding account for major operational and capital costs. As such, the study and development of comminution circuits have a fundamental importance for feasibility and optimization of compact Itabirite beneficiation. This work makes a comparison between comminution circuits for compact Itabirites from the Iron Quadrangle. The circuits developed are: a crushing and ball mill circuit (CB, a SAG mill and ball mill circuit (SAB and a single stage SAG mill circuit (SSSAG. For the SAB circuit, the use of pebble crushing is analyzed (SABC. An industrial circuit for 25 million tons of run of mine was developed for each route from tests on a pilot scale (grinding and industrial scale. The energy consumption obtained for grinding in the pilot tests was compared with that reported by Donda and Bond. The SSSAG route had the lowest energy consumption, 11.8kWh/t and the SAB route had the highest energy consumption, 15.8kWh/t. The CB and SABC routes had a similar energy consumption of 14.4 kWh/t and 14.5 kWh/t respectively.

Delayed Single Stage Perineal Posterior Urethroplasty.

Science.gov (United States)

Ali, Shahzad; Shahnawaz; Shahzad, Iqbal; Baloch, Muhammad Umar

2015-06-01

To determine the delayed single stage perineal posterior urethroplasty for treatment of posterior urethral stricture/distraction defect. Descriptive case series. Department of Urology, Jinnah Postgraduate Medical Centre, Karachi, from January 2009 to December 2011. Patients were selected for delayed single stage perineal posterior urethroplasty for treatment of posterior urethral stricture / distraction defect. All were initially suprapubically catheterized followed by definitive surgery after at least 3 months. Thirty male patients were analyzed with a mean follow-up of 10 months, 2 patients were excluded as they developed failure in first 3 months postoperatively. Mean patient's age was 26.25 ± 7.9 years. On follow-up, 7 patients (23.3%) experienced recurrent stricture during first 10 months. Five (16.6%) patients were treated successfully with single direct visual internal urethrotomy. Two patients (6.6%) had more than one direct visual internal urethrotomy and considered failed. Re-do perineal urethroplasty was eventually performed. The overall success rate was 93.3% with permissive criteria allowing single direct visual internal urethrotomy and 76.6% with strict criteria allowing no more procedures postoperatively. Posterior anastomotic urethroplasty offers excellent long-term results to patients with posterior urethral trauma and distraction defect even after multiple prior procedures.

Hanford Spent Nuclear Fuel Project evaluation of multi-canister overpack venting and monitoring options during staging of K basins fuel

Energy Technology Data Exchange (ETDEWEB)

Wiborg, J.C.

1995-12-01

This engineering study recommends whether multi-canister overpacks containing spent nuclear fuel from the Hanford K Basins should be staged in vented or a sealed, but ventable, condition during staging at the Canister Storage Building prior to hot vacuum conditioning and interim storage. The integrally related issues of MCO monitoring, end point criteria, and assessing the practicality of avoiding venting and Hot Vacuum Conditioning for a portion of the spent fuel are also considered.

Prediction of in-vitro developmental competence of early cleavage-stage mouse embryos with compact time-lapse equipment.

Science.gov (United States)

Pribenszky, Csaba; Losonczi, Eszter; Molnár, Miklós; Lang, Zsolt; Mátyás, Szabolcs; Rajczy, Klára; Molnár, Katalin; Kovács, Péter; Nagy, Péter; Conceicao, Jason; Vajta, Gábor

2010-03-01

Single blastocyst transfer is regarded as an efficient way to achieve high pregnancy rates and to avoid multiple pregnancies. Risk of cancellation of transfer due to a lack of available embryos may be reduced by early prediction of blastocyst development. Time-lapse investigation of mouse embryos shows that the time of the first and second cleavage (to the 2- and 3-cell stages, respectively) has a strong predictive value for further development in vitro, while cleavage from the 3-cell to the 4-cell stage has no predictive value. In humans, embryo fragmentation during preimplantation development has been associated with lower pregnancy rates and a higher incidence of developmental abnormalities. Analysis of time-lapse records shows that most fragmentation is reversible in the mouse and is resorbed in an average of 9 h. Daily or bi-daily microscopic checks of embryo development, applied routinely in human IVF laboratories, would fail to detect 36 or 72% of these fragmentations, respectively. Fragmentation occurring in a defined time frame has a strong predictive value for in-vitro embryo development. The practical compact system used in the present trial, based on the 'one camera per patient' principle, has eliminated the usual disadvantages of time-lapse investigations and is applicable for the routine follow-up of in-vitro embryo development. Copyright 2009 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

Operating single quantum emitters with a compact Stirling cryocooler.

Science.gov (United States)

Schlehahn, A; Krüger, L; Gschrey, M; Schulze, J-H; Rodt, S; Strittmatter, A; Heindel, T; Reitzenstein, S

2015-01-01

The development of an easy-to-operate light source emitting single photons has become a major driving force in the emerging field of quantum information technology. Here, we report on the application of a compact and user-friendly Stirling cryocooler in the field of nanophotonics. The Stirling cryocooler is used to operate a single quantum emitter constituted of a semiconductor quantum dot (QD) at a base temperature below 30 K. Proper vibration decoupling of the cryocooler and its surrounding enables free-space micro-photoluminescence spectroscopy to identify and analyze different charge-carrier states within a single quantum dot. As an exemplary application in quantum optics, we perform a Hanbury-Brown and Twiss experiment demonstrating a strong suppression of multi-photon emission events with g((2))(0) Stirling-cooled single quantum emitter under continuous wave excitation. Comparative experiments performed on the same quantum dot in a liquid helium (LHe)-flow cryostat show almost identical values of g((2))(0) for both configurations at a given temperature. The results of this proof of principle experiment demonstrate that low-vibration Stirling cryocoolers that have so far been considered exotic to the field of nanophotonics are an attractive alternative to expensive closed-cycle cryostats or LHe-flow cryostats, which could pave the way for the development of high-quality table-top non-classical light sources.

Operating single quantum emitters with a compact Stirling cryocooler

Energy Technology Data Exchange (ETDEWEB)

Schlehahn, A.; Krüger, L.; Gschrey, M.; Schulze, J.-H.; Rodt, S.; Strittmatter, A.; Heindel, T., E-mail: tobias.heindel@tu-berlin.de; Reitzenstein, S. [Institute of Solid State Physics, Technische Universität Berlin, 10623 Berlin (Germany)

2015-01-15

The development of an easy-to-operate light source emitting single photons has become a major driving force in the emerging field of quantum information technology. Here, we report on the application of a compact and user-friendly Stirling cryocooler in the field of nanophotonics. The Stirling cryocooler is used to operate a single quantum emitter constituted of a semiconductor quantum dot (QD) at a base temperature below 30 K. Proper vibration decoupling of the cryocooler and its surrounding enables free-space micro-photoluminescence spectroscopy to identify and analyze different charge-carrier states within a single quantum dot. As an exemplary application in quantum optics, we perform a Hanbury-Brown and Twiss experiment demonstrating a strong suppression of multi-photon emission events with g{sup (2)}(0) < 0.04 from this Stirling-cooled single quantum emitter under continuous wave excitation. Comparative experiments performed on the same quantum dot in a liquid helium (LHe)-flow cryostat show almost identical values of g{sup (2)}(0) for both configurations at a given temperature. The results of this proof of principle experiment demonstrate that low-vibration Stirling cryocoolers that have so far been considered exotic to the field of nanophotonics are an attractive alternative to expensive closed-cycle cryostats or LHe-flow cryostats, which could pave the way for the development of high-quality table-top non-classical light sources.

Evaluation of the fuel-element assembly non-hermeticity at its early stage

International Nuclear Information System (INIS)

Bliznyakova, V.A.; Shevel', V.N.; Ostapenko, V.I.

1983-01-01

The given paper deals with control of the fuel-element assembly shell state at the early stage of failure development. Technique for the fuel-element assembly shell state evaluation are described. A method for assembly failure detection, used at WWR of the Institute for Nuclear Research is described also

Fractional release of short-lived noble gases and iodine from HTGR fuel compact containing a fraction of coated fuel particles with through-coating defects

International Nuclear Information System (INIS)

Ogawa, Toru; Fukuda, Kosaku; Kobayashi, Fumiaki; Kikuchi, Teruo; Tobita, Tsutomu; Kashimura, Satoru; Kikuchi, Hironobu; Yamamoto, Katsumune.

1986-10-01

Fractional release (R/B) data of short-lived noble gases and iodine from sweep-gas irradiated HTGR fuel compacts were analyzed. Empirical formulas to predict R/B of 88 Kr as a function of temperature and fraction through-coating defects, and to calculate ratios of R/B's of other shortlived gases to that of 88 Kr were proposed. A method to predict R/B of iodine was also proposed. As for 131 I, a fission product of major safety concern, (R/B) I 131 ≅ (R/B) Xe 133 was predicted. Applying those methods, R/B from OGL-1 fuel element (5th and 6th) was predicted to show a good agreement with observation. (author)

Thermodynamic analysis of single-stage and multi-stage adsorption refrigeration cycles with activated carbon–ammonia working pair

International Nuclear Information System (INIS)

Xu, S.Z.; Wang, L.W.; Wang, R.Z.

2016-01-01

Highlights: • Activated carbon–ammonia multi-stage adsorption refrigerator was analyzed. • COP, exergetic efficiency and entropy production of cycles were calculated. • Single-stage cycle usually has the advantages of simple structure and high COP. • Multi-stage cycles adapt to critical conditions better than single-stage cycle. • Boundary conditions for choosing optimal cycle were summarized as tables. - Abstract: Activated carbon–ammonia multi-stage adsorption refrigeration cycle was analyzed in this article, which realized deep-freezing for evaporating temperature under −18 °C with heating source temperature much lower than 100 °C. Cycle mathematical models for single, two and three-stage cycles were established on the basis of thorough thermodynamic analysis. According to simulation results of thermodynamic evaluation indicators such as COP (coefficient of performance), exergetic efficiency and cycle entropy production, multi-stage cycle adapts to high condensing temperature, low evaporating temperature and low heating source temperature well. Proposed cycle with selected working pair can theoretically work under very severe conditions, such as −25 °C evaporating temperature, 40 °C condensing temperature, and 70 °C heating source temperature, but under these working conditions it has the drawback of low cycle adsorption quantity. It was found that both COP and exergetic efficiency are of great reference value in the choice of cycle, whereas entropy production is not so useful for cycle stage selection. Finally, the application boundary conditions of single-stage, two-stage, and three-stage cycles were summarized as tables according to the simulation results, which provides reference for choosing optimal cycle under different conditions.

Electron Microscopic Examination of Irradiated TRISO Coated Particles of Compact 6-3-2 of AGR-1 Experiment

Energy Technology Data Exchange (ETDEWEB)

Van Rooyen, Isabella Johanna [Idaho National Lab. (INL), Idaho Falls, ID (United States); Demkowicz, Paul Andrew [Idaho National Lab. (INL), Idaho Falls, ID (United States); Riesterer, Jessica Lori [Idaho National Lab. (INL), Idaho Falls, ID (United States); Miller, Brandon Douglas [Idaho National Lab. (INL), Idaho Falls, ID (United States); Janney, Dawn Elizabeth [Idaho National Lab. (INL), Idaho Falls, ID (United States); Harp, Jason Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ploger, Scott Arden [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2012-12-01

The electron microscopic examination of selected irradiated TRISO coated particles of the AGR-1 experiment of fuel compact 6-3-2 are presented in this report. Compact 6-3-2 refers to the compact in Capsule 6 at level 3 of Stack 2. The fuel used in capsule 6 compacts, are called the “baseline” fuel as it is fabricated with refined coating process conditions used to fabricate historic German fuel, because of its excellent irradiation performance with UO2 kernels. The AGR-1 fuel is however made of low-enriched uranium oxycarbide (UCO). Kernel diameters are approximately 350 µm with a U-235 enrichment of approximately 19.7%. Compact 6-3-2 has been irradiated to 11.3% FIMA compact average burn-up with a time average, volume average temperature of 1070.2°C and with a compact average fast fluence of 2.38E21 n/cm

CEA and AREVA R and D on V/HTR fuel fabrication with the CAPRI experimental manufacturing line

International Nuclear Information System (INIS)

Charollais, Francois; Fonquernie, Sophie; Perrais, Christophe; Perez, Marc; Cellier, Francois; Vitali, Marie-Pierre

2006-01-01

In the framework of the French V/HTR fuel development and qualification program, the Commissariat a l'Energie Atomique (CEA) and AREVA through its program called ANTARES (Areva New Technology for Advanced Reactor Energy Supply) conduct R and D projects covering the mastering of UO 2 coated particle and fuel compact fabrication technology. To fulfill this task, a review of past knowledge, of existing technologies and a preliminary laboratory scale work program have been conducted with the aim of retrieving the know-how on HTR coated particle and compact manufacture: - The different stages of UO 2 kernel fabrication GSP Sol-Gel process have been reviewed, reproduced and improved; - The experimental conditions for the chemical vapour deposition (CVD) of coatings have been defined on dummy kernels and development of innovative characterization methods has been carried out; - Former CERCA compacting process has been reviewed and updated. In parallel, an experimental manufacturing line for coated particles, named GAIA, and a compacting line based on former CERCA compacting experience have been designed, constructed and are in operation since early 2005 at CEA Cadarache and CERCA Romans, respectively. These two facilities constitute the CAPRI line (CEA and AREVA PRoduction Integrated line). The major objectives of the CAPRI line are: - to recover and validate past knowledge; - to permit the optimisation of reference fabrication processes for kernels and coatings and the investigation of alternative and innovative fuel design (UCO kernel, ZrC coating); - to test alternative compact process options; - to fabricate and characterize fuel required for irradiation and qualification purpose; - to specify needs for the fabrication of representative V/HTR TRISO fuel meeting industrial standards. This paper presents the progress status of the R and D conducted on V/HTR fuel particle and compact manufacture by mid 2005. (authors)

Delayed Single Stage Perineal Posterior Urethroplasty

International Nuclear Information System (INIS)

Ali, S.; Shahnawaz; Shahzad, I.; Baloch, M. U.

2015-01-01

Objective: To determine the delayed single stage perineal posterior urethroplasty for treatment of posterior urethral stricture/distraction defect. Study Design: Descriptive case series. Place and Duration of Study: Department of Urology, Jinnah Postgraduate Medical Centre, Karachi, from January 2009 to December 2011. Methodology: Patients were selected for delayed single stage perineal posterior urethroplasty for treatment of posterior urethral stricture / distraction defect. All were initially suprapubically catheterized followed by definitive surgery after at least 3 months. Results: Thirty male patients were analyzed with a mean follow-up of 10 months, 2 patients were excluded as they developed failure in first 3 months postoperatively. Mean patients age was 26.25 ± 7.9 years. On follow-up, 7 patients (23.3 percentage) experienced recurrent stricture during first 10 months. Five (16.6 percentage) patients were treated successfully with single direct visual internal urethrotomy. Two patients (6.6 percentage) had more than one direct visual internal urethrotomy and considered failed. Re-do perineal urethroplasty was eventually performed. The overall success rate was 93.3 percentage with permissive criteria allowing single direct visual internal urethrotomy and 76.6% with strict criteria allowing no more procedures postoperatively. Conclusion: Posterior anastomotic urethroplasty offers excellent long-term results to patients with posterior urethral trauma and distraction defect even after multiple prior procedures. (author)

Analysis of compaction initiation in human embryos by using time-lapse cinematography.

Science.gov (United States)

Iwata, Kyoko; Yumoto, Keitaro; Sugishima, Minako; Mizoguchi, Chizuru; Kai, Yoshiteru; Iba, Yumiko; Mio, Yasuyuki

2014-04-01

To analyze the initiation of compaction in human embryos in vitro by using time-lapse cinematography (TLC), with the goal of determining the precise timing of compaction and clarifying the morphological changes underlying the compaction process. One hundred and fifteen embryos donated by couples with no further need for embryo-transfer were used in this study. Donated embryos were thawed and processed, and then their morphological behavior during the initiation of compaction was dynamically observed via time-lapse cinematography (TLC) for 5 days. Although the initiation of compaction occurred throughout the period from the 4-cell to 16-cell stage, 99 (86.1 %) embryos initiated compaction at the 8-cell stage or later, with initiation at the 8-cell stage being most frequent (22.6 %). Of these 99 embryos, 49.5 % developed into good-quality blastocysts. In contrast, of the 16 (13.9 %) embryos that initiated compaction prior to the 8-cell stage, only 18.8 % developed into good-quality blastocysts. Embryos that initiated compaction before the 8-cell stage showed significantly higher numbers of multinucleated blastomeres, due to asynchronism in nuclear division at the third mitotic division resulting from cytokinetic failure. The initiation of compaction primarily occurs at the third mitotic division or later in human embryos. Embryos that initiate compaction before the 8-cell stage are usually associated with aberrant embryonic development (i.e., cytokinetic failure accompanied by karyokinesis).

Electron Microscopic Examination of Irradiated TRISO Coated Particles of Compact 6-3-2 of AGR-1 Experiment

Energy Technology Data Exchange (ETDEWEB)

Van Rooyen, Isabella Johanna [Idaho National Lab. (INL), Idaho Falls, ID (United States); Demkowicz, Paul Andrew [Idaho National Lab. (INL), Idaho Falls, ID (United States); Riesterer, Jessica Lori [Idaho National Lab. (INL), Idaho Falls, ID (United States); Miller, Brandon Douglas [Idaho National Lab. (INL), Idaho Falls, ID (United States); Janney, Dawn Elizabeth [Idaho National Lab. (INL), Idaho Falls, ID (United States); Harp, Jason Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ploger, Scott Arden [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2012-12-01

The electron microscopic examination of selected irradiated TRISO coated particles of the AGR-1 experiment of fuel compact 6-3-2 are presented in this report. Compact 6-3-2 refers to the compact in Capsule 6 at level 3 of Stack 2. The fuel used in capsule 6 compacts, are called the “baseline” fuel as it is fabricated with refined coating process conditions used to fabricate historic German fuel, because of its excellent irradiation performance with UO₂ kernels. The AGR-1 fuel is however made of low-enriched uranium oxycarbide (UCO). Kernel diameters are approximately 350 µm with a U-235 enrichment of approximately 19.7%. Compact 6-3-2 has been irradiated to 11.3% FIMA compact average burn-up with a time average, volume average temperature of 1070.2°C and with a compact average fast fluence of 2.38E21 n/cm

Single conversion stage amplifier - SICAM

Energy Technology Data Exchange (ETDEWEB)

Ljusev, P.

2005-12-15

This Ph.D. thesis presents a thorough analysis of the so called SICAM - SIngle Converter stage AMplifier approach to building direct energy conversion audio power amplifiers. The mainstream approach for building isolated audio power amplifiers today consists of isolated DC power supply and Class D amplifier, which essentially represents a two stage solution, where each of the components can be viewed as separate and independent part. The proposed SICAM solution strives for direct energy conversion from the mains to the audio output, by dedicating the operation of the components one to another and integrating their functions, so that the final audio power amplifier represents a single-stage topology with higher efficiency, lower volume, less board space, lower component count and subsequently lower cost. The SICAM approach is both applicable to non-isolated and isolated audio power amplifiers, but the problems encountered in these two cases are different. Non-isolated SICAM solutions are intended for both AC mains-connected and battery-powered devices. In non-isolated mains-connected SICAMs the main idea is to simplify the power supply or even provide integrated power factor correction (PFC) functions, while still maintaining low component stress and good audio performance by generally decreasing the input voltage level to the Class D audio power amplifier. On the other hand, non-isolated battery-powered SICAMs have to cope with the ever changing battery voltage and provide output voltage levels which are both lower and higher than the battery voltage, while still being simple and single-stage energy conversion solutions. In isolated SICAMs the isolation transformer adjusts the voltage level on the secondary side to the desired level, so the main challenges here are decreasing the size of the magnetic core and reducing the number and size of bulky reactive components as much as possible. The main focus of this thesis is directed towards the isolated SICAMs and

Design study and evaluation of fuel fabrication systems for FR fuel cycle

International Nuclear Information System (INIS)

Namekawa, Takashi; Tanaka, Kenya; Kawaguchi, Koichi; Koike, Kazuhiro; Shimuta, Hiroshi; Suzuki, Yoshihiro

2004-01-01

The plant concept for each FBR fuel fabrication system has been constructed and evaluated, which achieves economical improvement, decrease in the environmental burden, better resource utilization, and proliferation resistance by the various innovative techniques employed. The results are as follows: (1) For oxide fuels, the simplified pelletizing method has a high technical feasibility, and it is possible to apply this method to practical process at early stage, because this method is based on wealth results of a conventional method. (2) For oxide fuels, the sphere packing fuel fabrication system by gelation and vibro-compaction processes has the advantage of lesser dispersion of the fine powder due to the use of solution and granule in the process. However this system shoulders additional cost for the liquid waste treatment process to dispose a large bulk of process liquid waste. (3) For the metal fuel, the casting system is generally expected to have high economical efficiency even for small-scale facilities, although verification for fabrication of the TRU alloy slug is required. (author)

Parametric analyses of single-zone thorium-fueled molten salt reactor fuel cycle options

International Nuclear Information System (INIS)

Powers, J.J.; Worrall, A.; Gehin, J.C.; Harrison, T.J.; Sunny, E.E.

2013-01-01

Analyses of fuel cycle options based on thorium-fueled Molten Salt Reactors (MSRs) have been performed in support of fuel cycle screening and evaluation activities for the United States Department of Energy. The MSR options considered are based on thermal spectrum MSRs with 3 different separations levels: full recycling, limited recycling, and 'once-through' operation without active separations. A single-fluid, single-zone 2250 MWth (1000 MWe) MSR concept consisting of a fuel-bearing molten salt with graphite moderator and reflectors was used as the basis for this study. Radiation transport and isotopic depletion calculations were performed using SCALE 6.1 with ENDF/B-VII nuclear data. New methodology developed at Oak Ridge National Laboratory (ORNL) enables MSR analysis using SCALE, modeling material feed and removal by taking user-specified parameters and performing multiple SCALE/TRITON simulations to determine the resulting equilibrium operating conditions. Parametric analyses examined the sensitivity of the performance of a thorium MSR to variations in the separations efficiency for protactinium and fission products. Results indicate that self-sustained operation is possible with full or limited recycling but once-through operation would require an external neutron source. (authors)

Acoustic emission during the compaction of brittle UO2 particles

International Nuclear Information System (INIS)

Hegron, Lise

2014-01-01

One of the options considered for recycling minor actinides is to incorporate about 10% to UO 2 matrix. The presence of open pores interconnected within this fuel should allow the evacuation of helium and fission gases to prevent swelling of the pellet and ultimately its interaction with the fuel clad surrounding it. Implementation of minor actinides requires working in shielded cell, reducing their retention and outlawing additions of organic products. The use of fragmentable particles of several hundred micrometers seems a good solution to control the microstructure of the green compacts and thus control the open porosity after sintering. The goal of this study is to monitor the compaction of brittle UO 2 particles by acoustic emission and to link the particle characteristics to the open porosity obtained after the compact sintering. The signals acquired during tensile strength tests on individual granules and compacts show that the acoustic emission allows the detection of the mechanism of fragmentation and enables identification of a characteristic waveform of this fragmentation. The influences of compaction stress, of the initial particle size distribution and of the internal cohesion of the granules, on the mechanical strength of the compact and on the microstructure and open porosity of the sintered pellets, are analyzed. By its ability to identify the range of fragmentation of the granules during compaction, acoustic emission appears as a promising technique for monitoring the compaction of brittle particles in the manufacture of a controlled porosity fuel. (author) [fr

Utilization of radiographic and ultrasonic testing for an evaluation of plate type fuel elements during manufacturing stages

International Nuclear Information System (INIS)

Brito, Mucio Jose Drummond de; Silva Junior, Silverio Ferreira da; Messias, Jose Marcos; Braga, Daniel Martins; Paula, Joao Bosco de

2005-01-01

Structural discontinuities can be introduced in the plate type fuel elements during the manufacturing stages due to mechanical processing conditions. The use of nondestructive testing methods to monitoring the fuel elements during the manufacturing stages presents a significant importance, contributing for manufacturing process improvement and cost reducing. This paper describes a procedure to be used detection and evaluation of structural discontinuities in plate type fuel elements during the manufacturing stages using the ultrasonic testing method and the radiographic testing method. The main results obtained are presented and discussed. (author)

Compact quantum dots for single-molecule imaging.

Science.gov (United States)

Smith, Andrew M; Nie, Shuming

2012-10-09

Single-molecule imaging is an important tool for understanding the mechanisms of biomolecular function and for visualizing the spatial and temporal heterogeneity of molecular behaviors that underlie cellular biology (1-4). To image an individual molecule of interest, it is typically conjugated to a fluorescent tag (dye, protein, bead, or quantum dot) and observed with epifluorescence or total internal reflection fluorescence (TIRF) microscopy. While dyes and fluorescent proteins have been the mainstay of fluorescence imaging for decades, their fluorescence is unstable under high photon fluxes necessary to observe individual molecules, yielding only a few seconds of observation before complete loss of signal. Latex beads and dye-labeled beads provide improved signal stability but at the expense of drastically larger hydrodynamic size, which can deleteriously alter the diffusion and behavior of the molecule under study. Quantum dots (QDs) offer a balance between these two problematic regimes. These nanoparticles are composed of semiconductor materials and can be engineered with a hydrodynamically compact size with exceptional resistance to photodegradation (5). Thus in recent years QDs have been instrumental in enabling long-term observation of complex macromolecular behavior on the single molecule level. However these particles have still been found to exhibit impaired diffusion in crowded molecular environments such as the cellular cytoplasm and the neuronal synaptic cleft, where their sizes are still too large (4,6,7). Recently we have engineered the cores and surface coatings of QDs for minimized hydrodynamic size, while balancing offsets to colloidal stability, photostability, brightness, and nonspecific binding that have hindered the utility of compact QDs in the past (8,9). The goal of this article is to demonstrate the synthesis, modification, and characterization of these optimized nanocrystals, composed of an alloyed HgxCd1-xSe core coated with an

Single-stage-to-orbit versus two-stage-two-orbit: A cost perspective

Science.gov (United States)

Hamaker, Joseph W.

1996-03-01

This paper considers the possible life-cycle costs of single-stage-to-orbit (SSTO) and two-stage-to-orbit (TSTO) reusable launch vehicles (RLV's). The analysis parametrically addresses the issue such that the preferred economic choice comes down to the relative complexity of the TSTO compared to the SSTO. The analysis defines the boundary complexity conditions at which the two configurations have equal life-cycle costs, and finally, makes a case for the economic preference of SSTO over TSTO.

Single stage reconstruction of complex anterior urethral strictures

Directory of Open Access Journals (Sweden)

Deepak Dubey

2001-01-01

Full Text Available Purpose: Single stage reconstruction of long, com-plex urethral strictures is technically demanding and may require the use of more than one tissue transfer technique. We describe our experience in the manage-ment of such strictures with a variety of urethroplasty techniques. Materials and Methods: Between 1989 and 1999, 25 men (mean age 38.5 years underwent single stage re-construction of panurethral, multiple segment or focally dense strictures [mean length 11.2 cm (range 8-17 cm]. 8 patients had combined substitution urethroplasty with a circumpenile fasciocutaneous flap and a free graft of bladder/buccal mucosa or tunica vaginalis . flap. In 10 patients a single tissue transfer technique was used. 3 patients underwent an augmented roof/floor strip ure-throplasty with a penile skin flap. 4 patients with multi-ple segment strictures (separate pendulous and bulbar underwent distal onlay flap and proximal anastomotic urethroplasty. Results: The median ,follow-up was 46.5 months (range 6-88 months. The mean postoperative flow rate improved to 22.5 ml/sec. 2 patients developed fistulae requiring repair. Recurrent stricture developed in 5 (20.8% patients, of which 2 were managed with visual internal urethrotomy, 2 with anastomotic urethroplasty and 1 with a two-stage procedure. Pseudodiverticulum and post-void dribbling were seen in 6 (25% patients. Conclusions: Successful outcome of single stage re-construction of long complex strictures can be achieved with a combination of various tissue transfer methods. The urologist who has a thorough knowledge of penile skin and urethral vascular anatomy and a wide array of substitution techniques in his armamentarium can un-dertake approach to such strictures.

Fuel-element failures in Hanford single-pass reactors 1944--1971

Energy Technology Data Exchange (ETDEWEB)

Gydesen, S.P.

1993-07-01

The primary objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation dose that individuals could have received as a result of emissions since 1944 from the US Department of Energy`s (DOE) Hanford Site near Richland, Washington. To estimate the doses, the staff of the Source Terms Task use operating information from historical documents to approximate the radioactive emissions. One source of radioactive emissions to the Columbia River came from leaks in the aluminum cladding of the uranium metal fuel elements in single-pass reactors. The purpose of this letter report is to provide photocopies of the documents that recorded these failures. The data from these documents will be used by the Source Terms Task to determine the contribution of single-pass reactor fuel-element failures to the radioactivity of the reactor effluent from 1944 through 1971. Each referenced fuel-element failure occurring in the Hanford single-pass reactors is addressed. The first recorded failure was in 1948, the last in 1970. No records of fuel-element failures were found in documents prior to 1948. Data on the approximately 2000 failures which occurred during the 28 years (1944--1971) of Hanford single-pass reactor operations are provided in this report.

Fuels planning: science synthesis and integration; environmental consequences fact sheet 14: Fuels reduction and compaction

Science.gov (United States)

Deborah Page-Dumroese

2005-01-01

Moving equipment and logs over the surface of forest soils causes gouges and ruts in the mineral soil, displaces organic matter, and can cause compaction. Compaction is the component of soil productivity most influenced by forest management, but the degree to which soils may be compacted depends on initial soil bulk density. For example, low bulk density soils (such as...

The manufacture, quality control and performance of KANUPP fuel

International Nuclear Information System (INIS)

Butt, M.I.; Salim, M.; Ahmad, I.

1989-01-01

KANUPP is a 137 MWe CANDU reactor. The fuel material is high-density sintered pellets (95-97% T.D.) of natural UO 2 in Zircaloy 4 sheaths. Reactor-grade UO 2 powder is precompacted, granulated, blended with 0.2% zinc stearate, and compacted into green pellets. The pellets are sintered in a reducing atmosphere, then finished by grinding, culled, and loaded into Zr-4 tubes. The welded elements are assembled into a fuel bundle. Quality control and quality assurance procedures are followed during all stages of manufacturing. The entire core of KANUPP now consists of locally manufactured fuel. Several bundles have already achieved the design burnup (8650 MWD/TU). There have never been any failures of these fuel bundles. (6 refs., 5 figs., 8 tabs.)

Development of ceramics based fuel, Phase I, Kinetics of UO2 sintering by vibration compacting of UO2 powder (Introductory report)

International Nuclear Information System (INIS)

Ristic, M.M.

1962-10-01

After completing the Phase I of the task related to development of ceramics nuclear fuel the following reports are presented: Kinetics of UO 2 sintering; Vibrational compacting and sintering of UO 2 ; Characterisation of of UO 2 powder by DDK and TGA methods; Separation of UO 2 powder

Comparative assessment of single-stage and two-stage anaerobic digestion for the treatment of thin stillage.

Science.gov (United States)

Nasr, Noha; Elbeshbishy, Elsayed; Hafez, Hisham; Nakhla, George; El Naggar, M Hesham

2012-05-01

A comparative evaluation of single-stage and two-stage anaerobic digestion processes for biomethane and biohydrogen production using thin stillage was performed to assess the impact of separating the acidogenic and methanogenic stages on anaerobic digestion. Thin stillage, the main by-product from ethanol production, was characterized by high total chemical oxygen demand (TCOD) of 122 g/L and total volatile fatty acids (TVFAs) of 12 g/L. A maximum methane yield of 0.33 L CH(4)/gCOD(added) (STP) was achieved in the two-stage process while a single-stage process achieved a maximum yield of only 0.26 L CH(4)/gCOD(added) (STP). The separation of acidification stage increased the TVFAs to TCOD ratio from 10% in the raw thin stillage to 54% due to the conversion of carbohydrates into hydrogen and VFAs. Comparison of the two processes based on energy outcome revealed that an increase of 18.5% in the total energy yield was achieved using two-stage anaerobic digestion. Copyright © 2012 Elsevier Ltd. All rights reserved.

Transport and leaching of technetium and uranium from spent UO2 fuel in compacted bentonite clay

International Nuclear Information System (INIS)

Ramebaeck, H.; Albinsson, Y.; Skaalberg, M.; Eklund, U.B.; Kjellberg, L.; Werme, L.

2000-01-01

The transport properties of Tc and U in compacted bentonite clay and the leaching behaviour of these elements from spent nuclear fuel in the same system were investigated. Pieces of spent UO 2 fuel were embedded in bentonite clay (ρ d =2100 kg/m 3 ). A low saline synthetic groundwater was used as the aqueous phase. After certain experimental times, the bentonite clay was cut into 0.1 mm thick slices, which were analysed for their content of Tc and U. Measurements were made using inductively coupled plasma mass spectrometry. Tc analysis comprised chemical separation. The analysis of U was done by means of detecting 236 U, since the natural content of U in bentonite clay made it impossible to distinguish between U originating from the fuel and the clay. The influence of different additives mixed into the clay was studied. The results showed an influence on both transport and leaching behaviour when metallic Fe was mixed into the clay. This indicates that Tc and U are reduced to their lower oxidation states as a result of this additive

design, construction and measured performance of a single-stage

African Journals Online (AJOL)

2012-11-03

Nov 3, 2012 ... Abstract. The design philosophy, construction and measured performances of a single stage, single entry centrifugal pump .... the tachometer spindle to be held against a recess in the motor shaft. The constructed centrifugal ...

Efficacy of single-stage and two-stage Fowler–Stephens laparoscopic orchidopexy in the treatment of intraabdominal high testis

Directory of Open Access Journals (Sweden)

Chang-Yuan Wang

2017-11-01

Conclusion: In the case of testis with good collateral circulation, single-stage F-S laparoscopic orchidopexy had the same safety and efficacy as the two-stage F-S procedure. Surgical options should be based on comprehensive consideration of intraoperative testicular location, testicular ischemia test, and collateral circumstances surrounding the testes. Under the appropriate conditions, we propose single-stage F-S laparoscopic orchidopexy be preferred. It may be appropriate to avoid unnecessary application of the two-stage procedure that has a higher cost and causes more pain for patients.

Correlating particle hardness with powder compaction performance.

Science.gov (United States)

Cao, Xiaoping; Morganti, Mikayla; Hancock, Bruno C; Masterson, Victoria M

2010-10-01

Assessing particle mechanical properties of pharmaceutical materials quickly and with little material can be very important to early stages of pharmaceutical research. In this study, a wide range of pharmaceutical materials were studied using atomic force microscopy (AFM) nanoindentation. A significant amount of particle hardness and elastic modulus data were provided. Moreover, powder compact mechanical properties of these materials were investigated in order to build correlation between the particle hardness and powder compaction performance. It was found that the materials with very low or high particle hardness most likely exhibit poor compaction performance while the materials with medium particle hardness usually have good compaction behavior. Additionally, the results from this study enriched Hiestand's special case concept on particle hardness and powder compaction performance. This study suggests that the use of AFM nanoindentation can help to screen mechanical properties of pharmaceutical materials at early development stages of pharmaceutical research.

Development of compact toroids injector for direct plasma controls

International Nuclear Information System (INIS)

Azuma, K.; Oda, Y.; Onozuka, M.; Uyama, T.; Nagata, M.; Fukumoto, N.

1995-01-01

The application of the compact toroids injector for direct plasma controls has been investigated. The compact toroids injection can fuel particles directly into the core of the plasma and modify the plasma profiles at the desired locations. The acceleration tests of the compact toroids have been conducted at Himeji Institute of Technology. The tests showed that the hydrogen compact toroid was accelerated up to 80km/s and the plasma density of the compact toroid was compressed to 1.2 x 10 21 m -3 . (orig.)

A fast and compact Fuel Rod Performance Simulator code for predictive, interpretive and educational purpose

International Nuclear Information System (INIS)

Lorenzen, J.

1990-01-01

A new Fuel rod Performance Simulator code FRPS has been developed, tested and benchmarked and is now available in different versions. The user may choose between the batch version INTERPIN producing results in form of listings or beforehand defined plots, or the interactive simulator code SIMSIM which is stepping through a power history under the control of user. Both versions are presently running on minicomputers and PC:s using EGA-Graphics. A third version is the implementation in a Studsvik Compact Simulator with FRPS being one of its various modules receiving the dynamic inputs from the simulator

Powder compaction in systems of bimodal distribution

Science.gov (United States)

Chattopadhyay, A. K.; Whittemore, O. J., Jr.

1973-01-01

The compaction of mixtures involving different particle sizes is discussed. The various stages of the compaction process include the rearrangement of particles, the filling of the interstices of the large particles by the smaller ones, and the change in particle size and shape upon further densification through the application of pressure. Experimental approaches and equipment used for compacting material are discussed together with the theoretical relations of the compacting process.

Compacted and Sintered Microstructure Depending on Uranium Powder Size in Zr-U Metallic Fuel

Energy Technology Data Exchange (ETDEWEB)

Yun, Chang Gun; Jun, Hyun-Joon; Ju, Jung Hwan; Lee, Ho Jin; Lee, Chong-Tak; Kim, Hyung Lae [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2017-03-15

In case of the uranium (U) and zirconium (Zr) powders which have been utilized for the production of a metallic fuel in the various nuclear applications, the homogenous distribution of U powders in the Zr-U pellet has influenced significantly on the nuclear fuel performance. The inhomogeneity in a powder process was changed by various intricate factors, e.g. powder size, shape, distribution and so on. Particularly, the U inhomogeneity in the Zr-U pellets occurs by segregation derived from the great gaps of densities between Zr and U during compaction of the mixed powders. In this study, the relationship between powder size and homogeneity was investigated by using the different-sized U powders. The microstructure in Zr-U pellets reveals more homogeneity when the weight ration of Zr and U powders are close to 1. In addition, homogeneous pellets which were produced by fine U powders have higher density because the homogeneity affects the alloying reaction during sintering and the densification behavior of pore induced by powder size.

Development of compact toroids injector for direct plasma controls

Energy Technology Data Exchange (ETDEWEB)

Azuma, K. [Mitsubishi Heavy Industries Ltd., Takasago (Japan); Oda, Y. [Mitsubishi Heavy Industries Ltd., Takasago (Japan); Onozuka, M. [Mitsubishi Heavy Industries Ltd., Takasago (Japan); Uyama, T. [Himeji Inst. of Tech. (Japan); Nagata, M. [Himeji Inst. of Tech. (Japan); Fukumoto, N. [Himeji Inst. of Tech. (Japan)

1995-12-31

The application of the compact toroids injector for direct plasma controls has been investigated. The compact toroids injection can fuel particles directly into the core of the plasma and modify the plasma profiles at the desired locations. The acceleration tests of the compact toroids have been conducted at Himeji Institute of Technology. The tests showed that the hydrogen compact toroid was accelerated up to 80km/s and the plasma density of the compact toroid was compressed to 1.2 x 10{sup 21}m{sup -3}. (orig.).

Article mounting and position adjustment stage

Science.gov (United States)

Cutburth, Ronald W.; Silva, Leonard L.

1988-01-01

An improved adjustment and mounting stage of the type used for the detection of laser beams is disclosed. A ring sensor holder has locating pins on a first side thereof which are positioned within a linear keyway in a surrounding housing for permitting reciprocal movement of the ring along the keyway. A rotatable ring gear is positioned within the housing on the other side of the ring from the linear keyway and includes an oval keyway which drives the ring along the linear keyway upon rotation of the gear. Motor-driven single-stage and dual (x, y) stage adjustment systems are disclosed which are of compact construction and include a large laser transmission hole.

Compact disposal of high-energy electron beams using passive or laser-driven plasma decelerating stage

Energy Technology Data Exchange (ETDEWEB)

Bonatto, A.; Schroeder, C. B.; Vay, J. -L.; Geddes, C. R.; Benedetti, C.; Esarey and, E.; Leemans, W. P.

2014-07-13

A plasma decelerating stage is investigated as a compact alternative for the disposal of high-energy beams (beam dumps). This could benefit the design of laser-driven plasma accelerator (LPA) applications that require transportability and or high-repetition-rate operation regimes. Passive and laser-driven (active) plasma-based beam dumps are studied analytically and with particle-in-cell (PIC) simulations in a 1D geometry. Analytical estimates for the beam energy loss are compared to and extended by the PIC simulations, showing that with the proposed schemes a beam can be efficiently decelerated in a centimeter-scale distance.

85,000-GPM, single-stage, single-suction LMFBR intermediate centrifugal pump

International Nuclear Information System (INIS)

Fair, C.E.; Cook, M.E.; Huber, K.A.; Rohde, R.

1983-01-01

The mechanical and hydraulic design features of the 85,000-gpm, single-stage, single-suction pump test article, which is designed to circulate liquid-sodium coolant in the intermediate heat-transport system of a Large-Scale Liquid Metal Fast Breeder Reactor (LS-LMFBR), are described. The design and analytical considerations used to satisfy the pump performance and operability requirements are presented. The validation of pump hydraulic performance using a hydraulic scale-model pump is discussed, as is the featute test for the mechanical-shaft seal system

Compact piezoelectric micromotor with a single bulk lead zirconate titanate stator

Science.gov (United States)

Yan, Liang; Lan, Hua; Jiao, Zongxia; Chen, Chin-Yin; Chen, I.-Ming

2013-04-01

The advance of micro/nanotechnology promotes the development of micromotors in recent years. In this article, a compact piezoelectric ultrasonic micromotor with a single bulk lead zirconate titanate stator is proposed. A traveling wave is generated by superposition of bending modes with 90° phase difference excited by d15 inverse piezoelectric effects. The operating principle simplifies the system structure significantly, and provides a miniaturization solution. A research prototype with the size of 0.75× 0.75×1.55 mm is developed. It can produce start-up torque of 0.27μNmand maximum speed of 2760 r/min at 14RMS.

Methodology of theory of stage-by-stage long-term preparation of sportsmen in single combats

Directory of Open Access Journals (Sweden)

Arziutov G.

2010-04-01

Full Text Available Results over of researches are brought on methodology of theory of stage-by-stage preparation of sportsmen in single combats. The structuralness of theory lies in possibility simple verifications of its substantive provisions, principles and laws. Development of methodology enables to begin creation of map of trainer on the stages of long-term preparation. Laws, conformities to law, principles and rules, must be collected in a map. A map enables the trainers of reserve sport to use its content during all stages of preparation of sportsman.

Status of Research on Pebble Bed HTR Fuel Fabrication Technology in Indonesia

International Nuclear Information System (INIS)

Rachmawati, M.; Sarjono; Ridwan; Langenati, R.

2014-01-01

Research on pebble bed HTR fuel fabrication is conducted in Indonesia. One of the aims is to build a knowledge base on pebble bed HTR fuel element fabrication technology for fuel procurement. The steps of research strategies are firstly to understand the basic design research of TRISO fuel, properties, and requirements, and secondly to understand the TRISO fuel manufacturing technology, which comprises fabrication and quality control, including its facility. Both steps are adopted from research and experiences of the countries with HTR fuel element fabrication technology. From the knowledge gained in the research, an experimental design of the process and a set of prototype process equipment for fabrication are developed, namely kernels production using external gelation process, TRISO coating of the kernel, and pebble compacting. Experiments using the prototypes have been conducted. Characterization of the kernel product, i.e. diameter, sphericity, density and O/U ratio, shows that the kernel product is still not in compliance with the specification requirements. These are deemed to be caused mainly by the selected vibrating system and the viscosity adjustment. Another major cause is the selected NH3 and air feeding method for both NH3 and air layer in the preparation for spherical droplets of liquid. The FB-CVD TRISO coating of the kernel has been experimented but unsuccessful by using an FB-CVD once‐through continuous coating process. For the pebble compacting, the process is still in the early stage of setting-up compaction equipment. This paper summarizes the current status of research on HTR fuel fabrication technology in Indonesia, the proposed process and its equipment setting-up for improvement of the kernel production. The knowledge and lessons learned gained from the research is useful and can be an assistance in planning for fuel development laboratory facilities procurement, formulating User Requirement Document and Bid Invitation Specification for

Response Of Lowland Rice To Soil Compaction

International Nuclear Information System (INIS)

Idawati; Haryanto

2000-01-01

Soil compaction, as a new tillage practice for paddy soil, is to substitute pudding in order to reduce land preparation cost. To study response of lowland rice to soil compaction, a pot experiment has been conducted which took place in the greenhouse of P3TIR-BATAN. Soil for experiment was taken from pusakanegara. Two factors (degree of soil compaction and rice variety) were combined. Degree of compaction was split into 3 levels (DI = normal; D215% more compact than normal; 30 % more compact than normal), and rice variety into 2 levels (IR64 and Atomita IV). KH 2 32 PO 4 solution was injected into the soil surrounding rice clump to test the root activity at blooming stage of rice plant. Data resulted from this experiment is presented together with additional data from some other experiments of fertilization in the research s erie to study soil compaction. Some information's from experiment results are as following. Both rice varieties tested gave the same response to soil compaction. Root activity, according to data of 32 P absorbed by plant, was not harmed by soil compaction at the degree tested in the experiment. This prediction is supported by the growth by rice observed at generative growth stage, in pot experiment as well as in field experiment, which showed that soil compaction tested did not decrease rice yield but in opposite in tended to increase the yield. In practising soil compaction in land preparation, fertilizers should be applied by deep placement to have higher increasing is rice yield

Experimental determination of optimal clamping torque for AB-PEM Fuel cell

Directory of Open Access Journals (Sweden)

Noor Ul Hassan

2016-04-01

Full Text Available Polymer electrolyte Membrane (PEM fuel cell is an electrochemical device producing electricity by the reaction of hydrogen and oxygen without combustion. PEM fuel cell stack is provided with an appropriate clamping torque to prevent leakage of reactant gases and to minimize the contact resistance between gas diffusion media (GDL and bipolar plates. GDL porous structure and gas permeability is directly affected by the compaction pressure which, consequently, drastically change the fuel cell performance. Various efforts were made to determine the optimal compaction pressure and pressure distributions through simulations and experimentation. Lower compaction pressure results in increase of contact resistance and also chances of leakage. On the other hand, higher compaction pressure decreases the contact resistance but also narrows down the diffusion path for mass transfer from gas channels to the catalyst layers, consequently, lowering cell performance. The optimal cell performance is related to the gasket thickness and compression pressure on GDL. Every stack has a unique assembly pressure due to differences in fuel cell components material and stack design. Therefore, there is still need to determine the optimal torque value for getting the optimal cell performance. This study has been carried out in continuation of deve­lopment of Air breathing PEM fuel cell for small Unmanned Aerial Vehicle (UAV application. Compaction pressure at minimum contact resistance was determined and clamping torque value was calcu­la­ted accordingly. Single cell performance tests were performed at five different clamping torque values i.e 0.5, 1.0, 1.5, 2.0 and 2.5 N m, for achieving optimal cell per­formance. Clamping pressure distribution tests were also performed at these torque values to verify uniform pressure distribution at optimal torque value. Experimental and theoretical results were compared for making inferences about optimal cell perfor­man­ce. A

Standard examination stage for the fuels and materials examination facility

International Nuclear Information System (INIS)

Hess, J.W.; Frandsen, G.B.

1980-01-01

A Standard Examination Stage (SES) has been designed, fabricated, and tested for use in the Fuel and Materials Examination Facility (FMEF) at the Hanford Reservation near Richland, WA. The SES will perform multiple functions in a variety of nuclear fuel, absorber, and blanket pin handling, positioning, and examination operations in 11 of 22 work stations in the FMEF Nondestructive Examination (NDE) cell. Preprogrammable, automated, closed loop computer control provides precision positioning in the X, Y and Z directions and in pin rotational positioning. Modular construction of both the mechanical hardware and the electrical and control system has been used to facilitate in-cell maintainability

Single-session versus staged procedures for elective multivessel percutaneous coronary intervention.

Science.gov (United States)

Toyota, Toshiaki; Morimoto, Takeshi; Shiomi, Hiroki; Yamaji, Kyohei; Ando, Kenji; Ono, Koh; Shizuta, Satoshi; Saito, Naritatsu; Kato, Takao; Kaji, Shuichiro; Furukawa, Yutaka; Nakagawa, Yoshihisa; Kadota, Kazushige; Horie, Minoru; Kimura, Takeshi

2018-06-01

To clarify the effect of single-session multivessel percutaneous coronary intervention (PCI) strategy relative to the staged multivessel strategy on clinical outcomes in patients with stable coronary artery disease (CAD) or non-ST-elevation acute coronary syndrome. In the Coronary REvascularisation Demonstrating Outcome Study in Kyoto PCI/coronary artery bypass grafting registry cohort-2, there were 2018 patients who underwent elective multivessel PCI. Primary outcome measure was composite of all-cause death, myocardial infarction and stroke at 5-year follow-up. Single-session multivessel PCI and staged multivessel PCI were performed in 707 patients (35.0%) and 1311 patients (65.0%), respectively. The cumulative 5-year incidence of and adjusted risk for the primary outcome measure were not significantly different between the single-session and staged groups (26.7% vs 23.0%, p=0.45; HR 0.91, 95% CI 0.72 to 1.16, p=0.47). The 30-day incidence of all-cause death was significantly higher in the single-session group than in the staged group (1.1% vs 0.2%, p=0.009). However, the causes of death in 11 patients who died within 30 days were generally not related to the procedural complications, but related to the serious clinical status before PCI. For the subgroup analyses including age, gender, extent of CAD, severe chronic kidney disease and heart failure, there was no significant interaction between the subgroup factors and the effect of the single-session strategy relative to the staged strategy for the primary outcome measure. The single-session multivessel PCI strategy was associated with at least comparable 5-year clinical outcomes compared with the staged multivessel PCI, although the prevalence of the single-session strategy was low in the present study. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Optimization of material flow in the nuclear fuel cycle using a cyclic multi-stage production-to-inventory model

International Nuclear Information System (INIS)

DePorter, E.L.

1977-01-01

The nuclear fuel cycle is modelled as a cyclic, multi-stage production-to-inventory system. The objective is to meet a known deterministic demand for energy while minimizing acquisition, production, and inventory holding costs for all stages of the fuel cycle. The model allows for cyclic flow (feedback) of materials, material flow conversion factors at each stage, production lag times at each stage, and for escalating costs of uranium ore. It does not allow shortages to occur in inventories. The model is optimized by the application of the calculus of variations and specifically through recently developed theorems on the solution of functionals constrained by inequalities. The solution is a set of optimal cumulative production trajectories which define the stagewise production rates. Analysis of these production rates reveals the optimal nuclear fuel cycle costs and that inventories (stockpiles) occur in uranium fields, enriched uranium hexafluoride, and fabricated fuel assemblies. An analysis of the sensitivity of the model to variation in three important parameters is performed

Fuel temperature prediction during high burnup HTGR fuel irradiation test. US-JAERI irradiation test for HTGR fuel

International Nuclear Information System (INIS)

Sawa, Kazuhiro; Fukuda, Kousaku; Acharya, R.

1995-01-01

This report describes the preirradiation thermal analysis of the HRB-22 capsule designed for an irradiation test in a removable beryllium position of the High Flux Isotope Reactor(HFIR) at Oak Ridge National Laboratory. This test is being carried out under Annex 2 of the Arrangement between the U.S. Department of Energy and the Japan Atomic Energy Research Institute on Cooperation in Research and Development regarding High-Temperature Gas-cooled Reactors. The fuel used in the test is an advanced type. The advanced fuel was designed aiming at burnup of about 10%FIMA(% fissions per initial metallic atom) which was higher than that of the first charge fuel for the High Temperature Engineering Test Reactor(HTTR) and was produced in Japan. CACA-2, a heavy isotope and fission product concentration calculational code for experimental irradiation capsules, was used to determine time-dependent fission power for the fuel compacts. The Heat Engineering and Transfer in Nine Geometries(HEATING) code was used to solve the steady-state heat conduction problem. The diameters of the graphite fuel body, which contains the fuel compacts, and of the primary pressure vessel were determined such that the requirements of running the fuel compacts at an average temperature less than 1250degC and of not exceeding a maximum fuel temperature of 1350degC were met throughout the four cycles of irradiation. The detail design of the capsule was carried out based on this analysis. (author)

Solution combustion synthesis of strontium aluminate, SrAl2O4, powders: single-fuel versus fuel-mixture approach.

Science.gov (United States)

Ianoş, Robert; Istratie, Roxana; Păcurariu, Cornelia; Lazău, Radu

2016-01-14

The solution combustion synthesis of strontium aluminate, SrAl2O4, via the classic single-fuel approach and the modern fuel-mixture approach was investigated in relation to the synthesis conditions, powder properties and thermodynamic aspects. The single-fuel approach (urea or glycine) did not yield SrAl2O4 directly from the combustion reaction. The absence of SrAl2O4 was explained by the low amount of energy released during the combustion process, in spite of the highly negative values of the standard enthalpy of reaction and standard Gibbs free energy. In the case of single-fuel recipes, the maximum combustion temperatures measured by thermal imaging (482 °C - urea, 941 °C - glycine) were much lower than the calculated adiabatic temperatures (1864 °C - urea, 2147 °C - glycine). The fuel-mixture approach (urea and glycine) clearly represented a better option, since (α,β)-SrAl2O4 resulted directly from the combustion reaction. The maximum combustion temperature measured in the case of a urea and glycine fuel mixture was the highest one (1559 °C), which was relatively close to the calculated adiabatic temperature (1930 °C). The addition of a small amount of flux, such as H3BO3, enabled the formation of pure α-SrAl2O4 directly from the combustion reaction.

Development of fuel cell systems for aircraft applications based on synthetic fuels

Energy Technology Data Exchange (ETDEWEB)

Pasel, J.; Samsun, R.C.; Doell, C.; Peters, R.; Stolten, D. [Forschungszentrum Juelich GmbH (Germany)

2010-07-01

At present, in the aviation sector considerable scientific project work deals with the development of fuel cell systems based on synthetic fuels to be integrated in future aircraft. The benefits of fuel cell systems in aircraft are various. They offer the possibility to simplify the aircraft layout. Important systems, i.e. the gas turbine powered auxiliary power unit (APU) for electricity supply, the fuel tank inserting system and the water tank, can be substituted by one single system, the fuel cell system. Additionally, the energy demand for ice protection can be covered assisted by fuel cell systems. These measures reduce the consumption of jet fuel, increase aircraft efficiency and allow the operation at low emissions. Additionally, the costs for aircraft related investments, for aircraft maintenance and operation can be reduced. On the background of regular discussions about environmental concerns (global warming) of kerosene Jet A-1 and its availability, which might be restricted in a few years, the aircraft industry is keen to employ synthetic, sulfur-free fuels such as Fischer-Tropsch fuels. These comprise Bio-To-Liquid and Gas-To-Liquid fuels. Within this field of research the Institute of Energy Research (IEF-3) in Juelich develops complete and compact fuel cell systems based on the autothermal reforming of these kinds of fuels in cooperation with industry. This paper reports about this work. (orig.)

Fabrication and characterization of fully ceramic microencapsulated fuels

Energy Technology Data Exchange (ETDEWEB)

Terrani, K.A., E-mail: kurt.terrani@gmail.com [Fuel Cycle and Isotopes Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Kiggans, J.O.; Katoh, Y. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Shimoda, K. [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Montgomery, F.C.; Armstrong, B.L.; Parish, C.M. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Hinoki, T. [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Hunn, J.D. [Fuel Cycle and Isotopes Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Snead, L.L. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

2012-07-15

The current generation of fully ceramic microencapsulated fuels, consisting of Tristructural Isotropic fuel particles embedded in a silicon carbide matrix, is fabricated by hot pressing. Matrix powder feedstock is comprised of alumina-yttria additives thoroughly mixed with silicon carbide nanopowder using polyethyleneimine as a dispersing agent. Fuel compacts are fabricated by hot pressing the powder-fuel particle mixture at a temperature of 1800-1900 Degree-Sign C using compaction pressures of 10-20 MPa. Detailed microstructural characterization of the final fuel compacts shows that oxide additives are limited in extent and are distributed uniformly at silicon carbide grain boundaries, at triple joints between silicon carbide grains, and at the fuel particle-matrix interface.

Compact frequency-modulation Q-switched single-frequency fiber laser at 1083 nm

International Nuclear Information System (INIS)

Zhang, Yuanfei; Feng, Zhouming; Xu, Shanhui; Mo, Shupei; Yang, Changsheng; Li, Can; Gan, Jiulin; Chen, Dongdan; Yang, Zhongmin

2015-01-01

A compact frequency-modulation Q-switched single-frequency fiber laser is demonstrated at 1083 nm. The short linear resonant cavity consists of a 12 mm long homemade Yb 3+ -doped phosphate fiber and a pair of fiber Bragg gratings (FBGs) in which the Q-switching and the frequency excursion is achieved by a tensile-induced period modulation. Over 375 MHz frequency-tuning range is achieved with a modulation frequency varying from tens to hundreds of kilohertz. The highest peak power of the output pulse reaching 6.93 W at the repetition rate of 10 kHz is obtained. (paper)

Simplified nuclear fuel reprocessing flowsheet: a single-cycle Purex process

International Nuclear Information System (INIS)

Montuir, M.; Dinh, B.; Baron, P.

2004-01-01

A simplified flowsheet with only one purification cycle instead of three is proposed for reprocessing spent nuclear fuel using the Purex process. A single-cycle flowsheet minimizes the process equipment required, the number of control points before transfer between process units, and the solvent and effluent quantities. For the uranium stream, an alpha barrier is used to strip any residual contaminants (Np, Th, Pu) from the uranium-loaded solvent. This additional step eliminates the need for a second uranium cycle. For the plutonium stream, an additional βγ co-decontamination step and a higher plutonium concentration are required before the oxalate conversion step; a plutonium 'half-cycle' is added downstream. The unloaded solvent from this half-cycle is returned to the selective plutonium stripping step, allowing significant plutonium half-cycle losses. It should be possible to reduce the number of stages in the half-cycle extraction step by recycling the raffinate to the upstream separation process. (authors)

TRANSPA: a code for transient thermal analysis of a single fuel pin

International Nuclear Information System (INIS)

Prenger, F.C.

1985-02-01

An analytical model (TRANSPA) for the transient thermal analysis of a single uranium carbide fuel pin was developed. This model uses thermal boundary conditions obtained from COBRA-WC output and calculates the transient thermal response of a single fuel pin to changes in internal power generation, coolant flowrate, or fuel pin physical configuration. The model uses the MITAS finite difference thermal analyzer. MITAS provides the means to input separate conductance models through the use of a user subroutine input capability. The model is a lumped-mass representation of the fuel pin using 26 nodes and 42 conductors. Run time for each transient analysis is approximately one minute of central processor time on the NOS operating system

Fabrication of HTTR first loading fuel

International Nuclear Information System (INIS)

Kato, S.; Yoshimuta, S.; Hasumi, T.; Sato, K.; Sawa, K.; Suzuki, S.; Mogi, H.; Shiozawa, S.; Tanaka, T.

2001-01-01

This paper summarizes the fabrication of the first loading fuel for HTTR, High Temperature engineering Test Reactor constructed by JAERI, Japan Atomic Energy Research Institute. The fuel fabrication started at the HTR fuel facility of NFI, Nuclear Fuel Industries, Ltd., June 1995. 4,770 fuel rods were fabricated through the fuel kernel, coated fuel particle and fuel compaction process, then 150 fuel elements were assembled in the reactor building December 1997. Fabrication technology for the fuel was established through a lot of R and D activities and fabrication experience of irradiation examination samples spread over about 30 years. Most of all, very high quality and production efficiency of fuel were achieved by the development of the fuel kernel process using the vibration dropping technology, the continuous 4-layer coating process and the automatic compaction process. As for the inspection technology, the development of the automatic measurement equipment for coated layer thickness of a coated fuel particle and uranium content of a fuel compact contributed to the higher reliability and rationalization of the inspection process. The data processing system for the fabrication and quality control, which was originally developed by NFI, made possible not only quick feedback of statistical quality data to the fabrication processes, but also automatic document preparation, such as inspection certificates and accountability control reports. The quality of the first loading fuel fully satisfied the design specifications for the fuel. In particular, average bare uranium fraction and SiC defective fraction of fuel compacts were 2x10 -6 and 8x10 -5 , respectively. According to the preceding irradiation examinations being performed at JMTR, Japan Materials Testing Reactor of JAERI, the specimen sampled from the first loading fuel shows good irradiation performance. (author)

Proportioning equipment for vibration filling and compacting of grain materials in pipe containers, especially of fuel elements

International Nuclear Information System (INIS)

Pinkas, V.; Filip, Z.; Beranek, J.

1981-01-01

The equipment consists of a base plate to which are attached the fastening collar fo the pipe container and the guide column with the height-adjustable support. The filling pipe is fixed to the support. The proportioning equipment prevents particles of grain material from segregation, thus allowing to achieve homogeneity of the material in the whole volume to be compacted. It also allows determining the height of the column of material in the pipe container without destructive effects on the stacked material. The equipment is designed for the manufacture of shortened fuel elements. (J.B.)

Structural design concept and static analysis of CANDU spent fuel compact dry storage system

International Nuclear Information System (INIS)

Choi, K. S.; Yang, K. H.; Paek, C. R.; Jung, J. S.; Lee, H. Y.

2003-01-01

In this study, an structural design concept on CANDU spent fuel compact dry storage system MACSTOR/KN-400 module has been established with a view to optimally design the structural members of the system. Design loads, loading combination and structural safety criteria of the module were reviewed assuming W olsung Site. The static analysis of the module showed that compressive stress concentration due to dead load and live load occurred around the center of roof slab. Maximum stress resulted from dead load is about twice as much as the stress from live load, and structural behavior of module caused by wind load was not significant. The static analysis results will have influence on the reinforcement bar design of structural members with other structural analyses

Comparing a single-stage geocoding method to a multi-stage geocoding method: how much and where do they disagree?

Directory of Open Access Journals (Sweden)

Rice Kenneth

2007-03-01

Full Text Available Abstract Background Geocoding methods vary among spatial epidemiology studies. Errors in the geocoding process and differential match rates may reduce study validity. We compared two geocoding methods using 8,157 Washington State addresses. The multi-stage geocoding method implemented by the state health department used a sequence of local and national reference files. The single-stage method used a single national reference file. For each address geocoded by both methods, we measured the distance between the locations assigned by each method. Area-level characteristics were collected from census data, and modeled as predictors of the discordance between geocoded address coordinates. Results The multi-stage method had a higher match rate than the single-stage method: 99% versus 95%. Of 7,686 addresses were geocoded by both methods, 96% were geocoded to the same census tract by both methods and 98% were geocoded to locations within 1 km of each other by the two methods. The distance between geocoded coordinates for the same address was higher in sparsely populated and low poverty areas, and counties with local reference files. Conclusion The multi-stage geocoding method had a higher match rate than the single-stage method. An examination of differences in the location assigned to the same address suggested that study results may be most sensitive to the choice of geocoding method in sparsely populated or low-poverty areas.

Effect of proton-conduction in electrolyte on electric efficiency of multi-stage solid oxide fuel cells

Science.gov (United States)

Matsuzaki, Yoshio; Tachikawa, Yuya; Somekawa, Takaaki; Hatae, Toru; Matsumoto, Hiroshige; Taniguchi, Shunsuke; Sasaki, Kazunari

2015-07-01

Solid oxide fuel cells (SOFCs) are promising electrochemical devices that enable the highest fuel-to-electricity conversion efficiencies under high operating temperatures. The concept of multi-stage electrochemical oxidation using SOFCs has been proposed and studied over the past several decades for further improving the electrical efficiency. However, the improvement is limited by fuel dilution downstream of the fuel flow. Therefore, evolved technologies are required to achieve considerably higher electrical efficiencies. Here we present an innovative concept for a critically-high fuel-to-electricity conversion efficiency of up to 85% based on the lower heating value (LHV), in which a high-temperature multi-stage electrochemical oxidation is combined with a proton-conducting solid electrolyte. Switching a solid electrolyte material from a conventional oxide-ion conducting material to a proton-conducting material under the high-temperature multi-stage electrochemical oxidation mechanism has proven to be highly advantageous for the electrical efficiency. The DC efficiency of 85% (LHV) corresponds to a net AC efficiency of approximately 76% (LHV), where the net AC efficiency refers to the transmission-end AC efficiency. This evolved concept will yield a considerably higher efficiency with a much smaller generation capacity than the state-of-the-art several tens-of-MW-class most advanced combined cycle (MACC).

Single-stage Acetabular Revision During Two-stage THA Revision for Infection is Effective in Selected Patients.

Science.gov (United States)

Fink, Bernd; Schlumberger, Michael; Oremek, Damian

2017-08-01

The treatment of periprosthetic infections of hip arthroplasties typically involves use of either a single- or two-stage (with implantation of a temporary spacer) revision surgery. In patients with severe acetabular bone deficiencies, either already present or after component removal, spacers cannot be safely implanted. In such hips where it is impossible to use spacers and yet a two-stage revision of the prosthetic stem is recommended, we have combined a two-stage revision of the stem with a single revision of the cup. To our knowledge, this approach has not been reported before. (1) What proportion of patients treated with single-stage acetabular reconstruction as part of a two-stage revision for an infected THA remain free from infection at 2 or more years? (2) What are the Harris hip scores after the first stage and at 2 years or more after the definitive reimplantation? Between June 2009 and June 2014, we treated all patients undergoing surgical treatment for an infected THA using a single-stage acetabular revision as part of a two-stage THA exchange if the acetabular defect classification was Paprosky Types 2B, 2C, 3A, 3B, or pelvic discontinuity and a two-stage procedure was preferred for the femur. The procedure included removal of all components, joint débridement, definitive acetabular reconstruction (with a cage to bridge the defect, and a cemented socket), and a temporary cemented femoral component at the first stage; the second stage consisted of repeat joint and femoral débridement and exchange of the femoral component to a cementless device. During the period noted, 35 patients met those definitions and were treated with this approach. No patients were lost to followup before 2 years; mean followup was 42 months (range, 24-84 months). The clinical evaluation was performed with the Harris hip scores and resolution of infection was assessed by the absence of clinical signs of infection and a C-reactive protein level less than 10 mg/L. All

On the possibility of reprocessing of fuel elements of dispersion type with copper matrix by pyrochemical methods

International Nuclear Information System (INIS)

Vasin, B.D.; Ivanov, V.A.; Shchetinskij, A.V.; Vavilov, S.K.; Savochkin, Yu.P.; Bychkov, A.V.; Kormilitsyn, M.V.

2005-01-01

A consideration is given to pyrochemical processes suitable for separation of uranium dioxide from structural materials when reprocessing cermet type fuel elements. The estimation of the possibility to apply liquid antimony and bismuth, potassium and copper chlorides melts is made. The specimens compacted of copper and uranium dioxide powders in a stainless steel can are used as simulators of fuel element sections. It is concluded that the dissolution of structural materials in molten salts at the stage of uranium dioxide concentration is the process of choice for reprocessing of dispersion type fuel elements [ru

Investigation of Advanced Propellants to Enable Single Stage to Orbit Launch Vehicles

National Research Council Canada - National Science Library

Mossman, Jason

2006-01-01

Single-Stage-To-Orbit (SSTO) launch vehicles designs offer the promise of reduced complexity and cost compared to multi-stage vehicles, as only one stage need be developed, produced, and maintained...

Ideal magnetohydrodynamic simulations of low beta compact toroid injection into a hot strongly magnetized plasma

Energy Technology Data Exchange (ETDEWEB)

Liu, Wei [Los Alamos National Laboratory; Hsu, Scott [Los Alamos National Laboratory; Li, Hui [Los Alamos National Laboratory

2009-01-01

We present results from three-dimensional ideal magnetohydrodynamic simulations of low {beta} compact toroid (CT) injection into a hot strongly magnetized plasma, with the aim of providing insight into CT fueling of a tokamak with parameters relevant for ITER (International Thermonuclear Experimental Reactor). A regime is identified in terms of CT injection speed and CT-to-background magnetic field ratio that appears promising for precise core fueling. Shock-dominated regimes, which are probably unfavorable for tokamak fueling, are also identified. The CT penetration depth is proportional to the CT injection speed and density. The entire CT evolution can be divided into three stages: (1) initial penetration, (2) compression in the direction of propagation and reconnection, and (3) coming to rest and spreading in the direction perpendicular to injection. Tilting of the CT is not observed due to the fast transit time of the CT across the background plasma.

Single-Cylinder Diesel Engine Tests with Unstabilized Water-in-Fuel Emulsions

Science.gov (United States)

1978-08-01

A single-cylinder, four-stroke cycle diesel engine was operated on unstabilized water-in-fuel emulsions. Two prototype devices were used to produce the emulsions on-line with the engine. More than 350 test points were run with baseline diesel fuel an...

Restrained shrinkage experiments on coated particle fuel compacts in the temperature range 600-1200 deg C

International Nuclear Information System (INIS)

Blackstone, R.; Veringa, H.J.; Loelgen, R.

1976-05-01

Information on irradiation induced creep in reactor graphite and in fuel compact material is an essential ingredient in the design of any reactor core layout, because the creep plasticity of these materials diminishes the stresses which are built up in the fuel element during reactor operation. The restrained shrinkage method in which the shrinkage of a dumbbell shaped creep specimen is restrained by a graphite material which shows less irradiation shrinkage, offers a good possibility of performing a large series of tensile creep experiments in a limited irradiation volume. The irradiations, evaluations and the results of a series of restrained shrinkage experiments in which six different materials were tested, of which five were dummy coated particle compacts and one pure matrix material are described and discussed. These materials were irradiated in the High Flux Reactor of the Euratom Joint Research Centre in Petten/Netherlands. The irradiations were performed in three successive capsules at irradiation temperatures of 600 deg C, 900 deg C, 1050 deg C and 1200 deg C up to a neutron fluence of maximum 3x10 21 n.cm 2 (DNE). The post-irradiation examinations yielded plastic strains up to 2,3%, and values for the radiation creep coefficient were calculated, ranging from 4 to 8.10 -12 at 600 deg C and 8 to 30.10 -12 at 1200 deg C always given per dyn.cm -2 tensile stresses and per 10 20 n.cm -2 fluence units. Generally it was found that the creep behavior of these materials and the temperature dependence of the creep process could be compared with those for normal reactor graphites

Improvements in or relating to the manufacture of compact bodies from particulate material

International Nuclear Information System (INIS)

Lefevre, R.L.R.; Barbier, Y.M.J.; Thomas, J.P.; Sturge, D.W.J.

1976-01-01

It is stated that a problem arises in the manufacture of compact bodies of nuclear fuel from fuel particles. The particles may comprise spheroidal kernels of sintered UO 2 coated with layers of pyrocarbon and SiC and overcoated with layers of soft graphite. These particles are compressed in dies to form compact bodies, the layers of overcoating deforming to fill the spaces between the fuel particles. When the compact bodies are to be of elongated form pressure is applied axially through rams entering the ends of the die cavity, but this unfortunately leads to a variation in volume loading and matrix density of the particles, so that those particles and associated matrix at the ends of the elongated body are compacted to a higher degree than those at the center. Attempts to rectify this by increasing the pressure of compaction often results in breakage of the particles subjected to the greatest pressure. The method of manufacture described seeks to overcome this difficulty. The material is placed in a shaped die cavity, that partly defines the shape of the body, and is compacted between oppositely acting pairs of rams that extend over the full length of the cavity. Forces are then applied normal to the longitudinal axis of the cavity. The rams are shaped to combine with the cavity to define the shape of the compacted body. The addition of some end-compaction is advantageous, and for this purpose additional forces may be applied in the direction of the longitudinal axis. The die cavity may contain a mandrel arranged so that a hollow compact body is formed by compaction. (U.K.)

Mass-Radius diagram for compact stars

International Nuclear Information System (INIS)

Carvalho, G A; Jr, R M Marinho; Malheiro, M

2015-01-01

The compact stars represent the final stage in the evolution of ordinary stars, they are formed when a star ceases its nuclear fuel, in this point the process that sustain its stability will stop. After this, the internal pressure can no longer stand the gravitational force and the star colapses [2]. In this work we investigate the structure of these stars which are described by the equations of Tolman-Openheimer-Volkof (TOV) [1]. These equations show us how the pressure varies with the mass and radius of the star. We consider the TOV equations for both relativistic and non-relativistic cases. In the case of compact stars (white dwarfs and neutron stars) the internal pressure that balances the gravitational pressure is essentialy the pressure coming from the degeneracy of fermions. To have solved the TOV equations we need a equation of state that shows how this internal pressure is related to the energy density or mass density. Instead of using politropic equations of state we have solved the equations numericaly using the exact relativistic energy equation for the model of fermion gas at zero temperature. We obtain results for the mass-radius relation for white dwarfs and we compared with the results obtained using the politropic equations of state. In addition we discussed a good fit for the mass-radius relation. (paper)

Diffusion in compacted betonite

International Nuclear Information System (INIS)

Muurinen, A.; Rantanen, J.

1985-01-01

The objective of this report is to collect the literature bearing on the diffusion in compacted betonite, which has been suggested as possible buffer material for the disposal of spent fuel. Diffusion in a porous, water-saturated material is usually described as diffusion in the pore-water where sorption on the solid matter can delay the migration in the instationary state. There are also models which take into consideration that the sorbed molecules can also move while being sorbed. Diffusion experiments in compacted bentonite have been reported by many authors. Gases, anions, cations and actinides have been used as diffusing molecules. The report collects the results and the information on the measurement methods. On the basis of the results can be concluded that different particles possibly follow different diffusion mechanisms. The parameters which affect the diffusion seem to be for example the size, the electric charge and the sorption properties of the diffusing molecule. The report also suggest the parameters to be used in the diffusion calculation of the safety analyses of spent fuel disposal. (author)

Numerical Simulation of single-stage axial fan operation under dusty flow conditions

Science.gov (United States)

Minkov, L. L.; Pikushchak, E. V.

2017-11-01

Assessment of the aerodynamic efficiency of the single-stage axial flow fan under dusty flow conditions based on a numerical simulation using the computational package Ansys-Fluent is proposed. The influence of dust volume fraction on the dependences of the air volume flow rate and the pressure drop on the rotational speed of rotor is demonstrated. Matching functions for formulas describing a pressure drop and volume flow rate in dependence on the rotor speed and dust content are obtained by numerical simulation for the single-stage axial fan. It is shown that the aerodynamic efficiency of the single-stage axial flow fan decreases exponentially with increasing volume content of dust in the air.

Single Fuel Concept for Croatian Army Ground Vehicles

Directory of Open Access Journals (Sweden)

Robert Spudić

2008-05-01

Full Text Available During the process of approaching the European associationsand NATO the Republic of Croatia has accepted the singlefuel concept for all ground vehicles of the Croatian Army.Croatia has also undertaken to insure that all aircraft, motorvehicles and equipment with turbo-engines or with pressurizedfuel injection, for participation in NATO and PfP led operationscan • operate using the kerosene-based aviation fuel(NATO F-34. The paper gives a brief overview and the resultsof the earned out activities in the Armed Forces of the Republicof Croatia, the expected behaviour of the motor vehicle andpossible delays caused by the use of kerosene fuel (NATOF-34 as fuel for motor vehicles. The paper also gives the advantagesand the drawbacks of the single fuel concept. By acquiringnew data in the Croatian Armed Forces and experienceexchange with other nations about the method of using fuelF-34, the development of the technologies of engine manufacturingand its vital parts or by introducing new standards in theproductjon of fuels and additives new knowledge will certainlybe acquired for providing logistics support in the area of operations,and its final implementation will be a big step forward forthe Republic of Croatia towards Europe and NATO.

Study on the properties of the fuel compact for High Temperature Gas-cooled Reactor

International Nuclear Information System (INIS)

Lee, Chung-yong; Lee, Sung-yong; Choi, Min-young; Lee, Seung-jae; Jo, Young-ho; Lee, Young-woo; Cho, Moon-sung

2015-01-01

High Temperature Gas-cooled Reactors (HTGR), one of the Gen-IV reactors, have been using the fuel element which is manufactured by the graphite matrix, surrounding Tristructural-isotropic (TRISO)-coated Uranium particles. Factors with these characteristics effecting on the matrix of fuel compact are chosen and their impacts on the properties are studied. The fuel elements are considered with two types of concepts for HTGR, which are the block type reactor and the pebble bed reactor. In this paper, the cylinder-formed fuel element for the block type reactor is focused on, which consists of the large part of graphite matrix. One of the most important properties of the graphite matrix is the mechanical strength with the high reliability because the graphite matrix should be enabled to protect the TRISO particles from the irradiation environment and the impact from the outside. In this study, the three kinds of candidate graphites and the two kinds of candidate binder (Phenol and Polyvinyl butyral) were chosen and mixed with each other, formed and heated to measure mechanical properties. The objective of this research is to optimize the materials and composition of the mixture and the forming process by evaluating the mechanical properties before/after carbonization and heat treatment. From the mechanical test results, the mechanical properties of graphite pellets was related to the various conditions such as the contents and kinds of binder, the kinds of graphite and the heat treatments. In the result of the compressive strength and Vicker's hardness, the 10 wt% phenol binder added R+S graphite pellet was relatively higher mechanical properties than other pellets. The contents of Phenol binder, the kinds of graphite powder and the temperature of carbonization and heat treatment are considered important factors for the properties. To optimize the mechanical properties of fuel elements, the role of binders and the properties of graphites will be investigated as

Promising results after single-stage reconstruction of the nipple and areola complex

DEFF Research Database (Denmark)

Børsen-Koch, Mikkel; Bille, Camilla; Thomsen, Jørn B

2013-01-01

Introduction: Reconstruction of the nipple-areola complex (NAC) traditionally marks the end of breast reconstruction. Several different surgical techniques have been described, but most are staged procedures. This paper describes a simple single-stage approach. Material and Methods: We used...... reconstruction was 43 min. (30-50 min.). Conclusion: This simple single-stage NAC reconstruction seems beneficial for both patient and surgeon as it seems to be associated with faster reconstruction and reduced procedure-related time without compromising the aesthetic outcome or the morbidity associated...

Dependence of compressive strength of green compacts on pressure, density and contact area of powder particles

International Nuclear Information System (INIS)

Salam, A.; Akram, M.; Shahid, K.A.; Javed, M.; Zaidi, S.M.

1994-08-01

The relationship between green compressive strength and compacting pressure as well as green density has been investigated for uniaxially pressed aluminium powder compacts in the range 0 - 520 MPa. Two linear relationships occurred between compacting pressure and green compressive strength which corresponded to powder compaction stages II and III respectively, increase in strength being large during stage II and quite small in stage III with increasing pressure. On the basis of both, the experimental results and a previous model on cold compaction of powder particles, relationships between green compressive strength and green density and interparticle contact area of the compacts has been established. (author) 9 figs

Compact toroid refueling of reactors

International Nuclear Information System (INIS)

Gouge, M.J.; Hogan, J.T.; Milora, S.L.; Thomas, C.E.

1988-04-01

The feasibility of refueling fusion reactors and devices such as the International Thermonuclear Engineering Reactor (ITER) with high-velocity compact toroids is investigated. For reactors with reasonable limits on recirculating power, it is concluded that the concept is not economically feasible. For typical ITER designs, the compact toroid fueling requires about 15 MW of electrical power, with about 5 MW of thermal power deposited in the plasma. At these power levels, ideal ignition (Q = ∞) is not possible, even for short-pulse burns. The pulsed power requirements for this technology are substantial. 6 ref., 1 figs

Status of the Munich compact core reactor project

International Nuclear Information System (INIS)

Boening, K.; Glaeser, W.; Meier, J.; Rau, G.; Roehrmoser, A.; Steichele, E.

1991-01-01

A new national, high performance research reactor is being planned in Munich which shall provide an unperturbed thermal neutron flux of about 8.10 14 cm -2 s -1 at only 20 MW power. This object can be achieved with the concept of a small, light water cooled 'compact core' situated in the center of a large heavy water moderator tank. In the first part of this paper an overview is given on the status of the necessary fuel enrichment is discussed. In becomes clear that the potential of the compact core concept can only be developed without compromises when using highly enriched uranium in combination with the new high density fuel. (orig.)

Single-stage Modified Duhamel procedure for Hirschsprung′s disease : Our experience

Directory of Open Access Journals (Sweden)

Paras R Kothari

2012-01-01

Full Text Available Introduction: Primary single-stage pull-through for Hirschsprung′s disease (HD has been reported to give comparable surgical outcomes to staged operations with less morbidity. Herein, we present our experience with single-stage Modified Duhamel procedure for management of HD. Patients and Methods: This was a review of 48 cases of HD who underwent single-stage Modified Duhamel procedure without a protective colostomy. Results: The age at surgery ranged from 6 months to 10 years (median - 9 months, mean - 2.3 years. The average weight of the child was 7.2 kg (range, 4.9-22 kg. 38 (79.2% patients had classical rectosigmoid HD, the rest being long segment HD (the proximal most level being the splenic flexure. The average duration of surgery was 175 minutes (range, 130-245 minutes. The average blood loss was 45 ml. The average hospital stay was 7.2 days (range: 6-10 days. The major postoperative complications (n=3 included postoperative adhesive intestinal obstruction, anastomotic leak and persistent constipation due to residual aganglionosis. Each required a re-exploration. Minor complications included surgical site infection (n=3 and post-operative enterocolitis (n=3, which were managed conservatively. Six patients had constipation for a limited period post-operatively. All patients have a satisfactory functional outcome and normal development and growth. Conclusions: For HD, we recommend that single-stage Modified Duhamel procedure should be the preferred approach in view of its low morbidity, satisfactory functional outcome and avoidance of stoma, multiple surgeries and economic benefit in view of decreased hospital stay.

Lot-sizing for a single-stage single-product production system with rework of perishable production defectives

NARCIS (Netherlands)

Teunter, R.; Flapper, S.D.P.

2003-01-01

We consider a single-stage single-product production system. Produced units may be non-defective, reworkable defective, or non-reworkable defective. The system switches between production and rework. After producing a fixed number (N) of units, all reworkable defective units are reworked. Reworkable

Aligning laboratory and field compaction practices for asphalt - the influence of compaction temperature on mechanical properties

NARCIS (Netherlands)

Bijleveld, Frank; Miller, Seirgei Rosario; de Bondt, A.H.; Doree, Andries G.

2015-01-01

The approach used to identify a compaction temperature in the laboratory, based on binder viscosity, provides a single compaction temperature whereas, on-site, a roller operates within a temperature window. The effect on the density and mechanical properties of rolling during a temperature window

Safety of a New Compact Male Intermittent Catheter: Randomized, Cross-Over, Single-Blind Study in Healthy Male Volunteers

DEFF Research Database (Denmark)

Bagi, Per; Hannibalsen, Jane; Permild, Rikke

2011-01-01

in hematuria (p = 0.54) or discomfort/stinging/pain at first micturition (p = 0.56). During insertion, handling was easier (p = 0.0001) and touching the coating was necessary less often (2.2 vs. 81.3% of catheterizations; p catheter; it was preferred by nurses for 20 of 23......Introduction: A new compact male intermittent catheter was compared with a regular intermittent male catheter in terms of safety and acceptability. Methods: In this randomized, single-blind, cross-over study, healthy male volunteers were catheterized twice with a compact catheter and twice...... with a regular catheter. Results: 28 participants were enrolled. Mean ± SD discomfort (visual analogue scale; primary objective) was 2.25 ± 1.5 and 2.52 ± 1.8 for the compact and regular catheters, respectively (difference -0.27; 95% confidence interval -0.73 to 0.19); there was no significant difference...

Development of OTM Syngas Process and Testing of Syngas Derived Ultra-clean Fuels in Diesel Engines and Fuel Cells

Energy Technology Data Exchange (ETDEWEB)

E.T. Robinson; John Sirman; Prasad Apte; Xingun Gui; Tytus R. Bulicz; Dan Corgard; John Hemmings

2005-05-01

This final report summarizes work accomplished in the Program from January 1, 2001 through December 31, 2004. Most of the key technical objectives for this program were achieved. A breakthrough material system has lead to the development of an OTM (oxygen transport membrane) compact planar reactor design capable of producing either syngas or hydrogen. The planar reactor shows significant advantages in thermal efficiency and a step change reduction in costs compared to either autothermal reforming or steam methane reforming with CO{sub 2} recovery. Syngas derived ultra-clean transportation fuels were tested in the Nuvera fuel cell modular pressurized reactor and in International Truck and Engine single cylinder test engines. The studies compared emission and engine performance of conventional base fuels to various formulations of ultra-clean gasoline or diesel fuels. A proprietary BP oxygenate showed significant advantage in both applications for reducing emissions with minimal impact on performance. In addition, a study to evaluate new fuel formulations for an HCCI engine was completed.

Limits to the use of highly compacted bentonite as a deterrent for microbially influenced corrosion in a nuclear fuel waste repository

International Nuclear Information System (INIS)

Stroes-Gascoyne, Simcha; Hamon, Connie J.; Maak, Peter

2010-01-01

Highly compacted bentonite-based sealing materials are being developed for use in future geological repositories for nuclear fuel waste. Such materials would ensure a diffusion-controlled hydrology and additionally form a sorption barrier against radionuclide migration after container breach. Due to some inherent physical characteristics, such as low water activity (a w ), small pores and high swelling pressure, an additional role of highly compacted bentonite may be the elimination of significant microbial activity near used fuel containers, which would reduce the occurrence of microbially influenced corrosion (MIC) to insignificant levels. Several recent studies have examined the indigenous microbial populations in compacted bentonite and the factors that control microbial activity in such environments. Laboratory experiments with Wyoming MX-80 bentonite plugs, compacted to dry densities (DD's) of 0.8 to 2.0 g/cm 3 , and infiltrated with sterile distilled deionised water were carried out. At DD's of 0.8 and 1.3 g/cm 3 , culturability of heterotrophic aerobic bacteria increased by up to four orders of magnitude above back-ground levels. Anaerobic heterotrophic bacteria and SRB did not increase significantly above background levels in any of the tests. At higher DD's all culturability remained at, or fell below, the background levels. However, even at the highest DD tested, some culturability remained and viability was only mildly affected by high DD's. Therefore, the potential for increased microbial activity exist if a substantial reduction in DD of bentonite were to occur in a repository. The microbes that survive in dry as-purchased or highly compacted bentonite appear to be largely spore-forming organisms. Chi Fru and Athar (2008) studied the bacterial colonization of compacted MX-80 bentonite from the surrounding granitic groundwater population, at various temperature ranges. Results suggested that high temperature rather than high DD

Compact Fuel-Cell System Would Consume Neat Methanol

Science.gov (United States)

Narayanan, Sekharipuram; Kindler, Andrew; Valdez, Thomas

2007-01-01

In a proposed direct methanol fuel-cell electric-power-generating system, the fuel cells would consume neat methanol, in contradistinction to the dilute aqueous methanol solutions consumed in prior direct methanol fuel-cell systems. The design concept of the proposed fuel-cell system takes advantage of (1) electro-osmotic drag and diffusion processes to manage the flows of hydrogen and water between the anode and the cathode and (2) evaporative cooling for regulating temperature. The design concept provides for supplying enough water to the anodes to enable the use of neat methanol while ensuring conservation of water for the whole fuel-cell system.

JP-8 Catalytic Cracking for Compact Fuel Processors

National Research Council Canada - National Science Library

Campbell, Timothy

2004-01-01

...), kerosene, and diesel to produce hydrogen for fuel cell use, several issues arise. First, these fuels have high sulfur content, which can poison and deactivate components of the reforming process and the fuel cell stack...

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-08-01

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

Single-stage versus two-stage anaerobic fluidized bed bioreactors in treating municipal wastewater: Performance, foulant characteristics, and microbial community.

Science.gov (United States)

Wu, Bing; Li, Yifei; Lim, Weikang; Lee, Shi Lin; Guo, Qiming; Fane, Anthony G; Liu, Yu

2017-03-01

This study examined the receptive performance, membrane foulant characteristics, and microbial community in the single-stage and two-stage anaerobic fluidized membrane bioreactor (AFMBR) treating settled raw municipal wastewater with the aims to explore fouling mechanisms and microbial community structure in both systems. Both AFMBRs exhibited comparable organic removal efficiency and membrane performances. In the single-stage AFMBR, less soluble organic substances were removed through biosorption by GAC and biodegradation than those in the two-stage AFMBR. Compared to the two-stage AFMBR, the formation of cake layer was the main cause of the observed membrane fouling in the single-stage AFMBR at the same employed flux. The accumulation rate of the biopolymers was linearly correlated with the membrane fouling rate. In the chemical-cleaned foulants, humic acid-like substances and silicon were identified as the predominant organic and inorganic fouants respectively. As such, the fluidized GAC particles might not be effective in removing these substances from the membrane surfaces. High-throughout pyrosequencing analysis further revealed that beta-Proteobacteria were predominant members in both AFMBRs, which contributed to the development of biofilms on the fluidized GAC and membrane surfaces. However, it was also noted that the abundance of the identified dominant in the membrane surface-associated biofilm seemed to be related to the permeate flux and reactor configuration. Copyright © 2016 Elsevier Ltd. All rights reserved.

Compaction dynamics of crunchy granular material

Directory of Open Access Journals (Sweden)

Guillard François

2017-01-01

Full Text Available Compaction of brittle porous material leads to a wide variety of densification patterns. Static compaction bands occurs naturally in rocks or bones, and have important consequences in industry for the manufacturing of powder tablets or metallic foams for example. Recently, oscillatory compaction bands have been observed in brittle porous media like snow or cereals. We will discuss the great variety of densification patterns arising during the compaction of puffed rice, including erratic compaction at low velocity, one or several travelling compaction bands at medium velocity and homogeneous compaction at larger velocity. The conditions of existence of each pattern are studied thanks to a numerical spring lattice model undergoing breakage and is mapped to the phase diagram of the patterns based on dimensionless characteristic quantities. This also allows to rationalise the evolution of the compaction behaviour during a single test. Finally, the localisation of compaction bands is linked to the strain rate sensitivity of the material.

Compaction dynamics of crunchy granular material

Science.gov (United States)

Guillard, François; Golshan, Pouya; Shen, Luming; Valdès, Julio R.; Einav, Itai

2017-06-01

Compaction of brittle porous material leads to a wide variety of densification patterns. Static compaction bands occurs naturally in rocks or bones, and have important consequences in industry for the manufacturing of powder tablets or metallic foams for example. Recently, oscillatory compaction bands have been observed in brittle porous media like snow or cereals. We will discuss the great variety of densification patterns arising during the compaction of puffed rice, including erratic compaction at low velocity, one or several travelling compaction bands at medium velocity and homogeneous compaction at larger velocity. The conditions of existence of each pattern are studied thanks to a numerical spring lattice model undergoing breakage and is mapped to the phase diagram of the patterns based on dimensionless characteristic quantities. This also allows to rationalise the evolution of the compaction behaviour during a single test. Finally, the localisation of compaction bands is linked to the strain rate sensitivity of the material.

Single-stage anterior high sacrectomy for locally recurrent rectal cancer.

Science.gov (United States)

Fawaz, Khaled; Khaled, Fawaz; Smith, Myles J; Moises, Cukier; Smith, Andrew J; Yee, Albert J M

2014-03-01

A review of prospectively collected data on a consecutive series of patients undergoing single-stage anterior high sacrectomy for locally recurrent rectal carcinoma (LRRC). To determine the clinical outcome of patients who underwent anterior high sacrectomy for LRRC. High sacrectomy for oncological resection remains technically challenging. Surgery has the potential to achieve cure in carefully selected patients. Complete (R0) tumor excision in LRRC may require sacrectomy. High sacral resections (S3 and above) typically require a combined anterior/supine and posterior/prone procedure. We investigated our experience performing single-stage anterior high sacrectomy for LRRC. A consecutive series of patients with LRRC without systemic metastases who underwent resection with curative intent requiring high sacrectomy were identified. A review of a prospectively maintained colorectal and spine cancer database data was performed. An oblique dome high sacral osteotomy was performed during a single-stage anterior procedure. Outcome measures included surgical resection margin status, hospital length of stay, postoperative complications, physical functioning status, and overall survival. Nineteen consecutive patients were treated between 2002 and 2011. High sacrectomy was performed at sacral level S1-S2 in 4 patients, S2-S3 in 9 patients, and through S3 in 6 patients. An R0 resection margin was achieved histologically in all 19 cases. There was 1 early (<30 d) postoperative death (1/19, 5%). At median follow-up of 38 months, 13 patients had no evidence of residual disease, 1 was alive with disease, and 4 had died of disease. Morbidities occurred in 15 of the 19 patients (79%). Although high sacrectomy may require a combined anterior and posterior surgical approach, our series demonstrates the feasibility of performing single-stage anterior high sacrectomy in LRRC, with acceptable risks and outcomes compared with the literature. The procedure described by us for LRRC lessens

Compact power reactor

International Nuclear Information System (INIS)

Wetch, J.R.; Dieckamp, H.M.; Wilson, L.A.

1978-01-01

There is disclosed a small compact nuclear reactor operating in the epithermal neutron energy range for supplying power at remote locations, as for a satellite. The core contains fuel moderator elements of Zr hydride with 7 w/o of 93% enriched uranium alloy. The core has a radial beryllium reflector and is cooled by liquid metal coolant such as NaK. The reactor is controlled and shut down by moving portions of the reflector

Release of fission products from irradiated SRP fuels at elevated temperatures: Data report on the second stage of the SRP source term study

International Nuclear Information System (INIS)

Woodley, R.E.

1987-03-01

The measurements of the release of fission products from irradiated Savannah River Plant (SRP) fuels at elevated temperatures reported herein extend the results of the first stage of the investigation to two additional fuel temperatures. In the first stage, two types of SRP fuels, a uranium-aluminum alloy designated MK-16 and a U 3 O 8 -aluminum cermet designated OX-2, were exposed to one of three different atmospheres, argon, air, or 80% steam-20% argon, at either of two different temperatures, 700 or 1100 0 C. In the second stage, the two fuels and three atmospheres remained the same, but the fuel temperatures, 850 and 1000 0 C, were intermediate to those previously employed. For each set of conditions, the measurements were repeated and, thus, the second stage of the study, like the first, consisted of 24 separate runs. This report presents the results of the 24 second-stage measurements

Compacted spent-fuel storage--designs and problems

International Nuclear Information System (INIS)

Rubinstein, H.J.; Gilcrest, J.D.; Kendall, W.R.

1979-01-01

Typical rack designs, licensing, contracting methods, installation and operational problems are described. Due to the lack of reprocessing and independent fuel storage facilities, new plants built in the United States will continue to install high-density spent-fuel storage racks. As to the rack designs, the most significant feature is the introduction of freestanding rack designs. The trends in spent-fuel storage appear to be toward the use of high-density racks, either with or without absorber, for all plants in the design, construction, or operation phase; the use of freestanding rack designs; and the separation of engineering and fabrication during procurement

Compact Ag@Fe3O4 Core-shell Nanoparticles by Means of Single-step Thermal Decomposition Reaction

Science.gov (United States)

Brollo, Maria Eugênia F.; López-Ruiz, Román; Muraca, Diego; Figueroa, Santiago J. A.; Pirota, Kleber R.; Knobel, Marcelo

2014-10-01

A temperature pause introduced in a simple single-step thermal decomposition of iron, with the presence of silver seeds formed in the same reaction mixture, gives rise to novel compact heterostructures: brick-like Ag@Fe3O4 core-shell nanoparticles. This novel method is relatively easy to implement, and could contribute to overcome the challenge of obtaining a multifunctional heteroparticle in which a noble metal is surrounded by magnetite. Structural analyses of the samples show 4 nm silver nanoparticles wrapped within compact cubic external structures of Fe oxide, with curious rectangular shape. The magnetic properties indicate a near superparamagnetic like behavior with a weak hysteresis at room temperature. The value of the anisotropy involved makes these particles candidates to potential applications in nanomedicine.

Prediction of reservoir compaction and surface subsidence

Energy Technology Data Exchange (ETDEWEB)

De Waal, J.A.; Smits, R.M.M.

1988-06-01

A new loading-rate-dependent compaction model for unconsolidated clastic reservoirs is presented that considerably improves the accuracy of predicting reservoir rock compaction and surface subsidence resulting from pressure depletion in oil and gas fields. The model has been developed on the basis of extensive laboratory studies and can be derived from a theory relating compaction to time-dependent intergranular friction. The procedure for calculating reservoir compaction from laboratory measurements with the new model is outlined. Both field and laboratory compaction behaviors appear to be described by one single normalized, nonlinear compaction curve. With the new model, the large discrepancies usually observed between predictions based on linear compaction models and actual (nonlinear) field behavior can be explained.

Criticality-safety analyses of compacted and water-flooded. SP-100 reactors

International Nuclear Information System (INIS)

Brandon, D.I.; Sapir, J.L.

1986-01-01

Reactivity calculations were performed to determine the sensitivity of three liquid metal-cooled, fast reactor designs to various accident environments. The concepts, proposed for the SP-100 Space Nuclear Power Program, included one thermionic and two fuel-pin designs. Numerous models of each core were developed to analyze the effect of core compaction and of water-flooded lattice spreading. Results indicate that those designs incorporating in-core control are least affected by core compaction and that the thermonic concept can best withstand expansion of the flooded fuel element array

Thorium utilisation in a small long-life HTR. Part III: Composite-rod fuel blocks

Energy Technology Data Exchange (ETDEWEB)

Verrue, Jacques, E-mail: jacques.verrue@polytechnique.org [Delft University of Technology, Reactor Institute Delft, Mekelweg 15, 2629 JB Delft (Netherlands); École Polytechnique (Member of ParisTech), 91128 Palaiseau Cedex (France); Ding, Ming, E-mail: dingm2005@gmail.com [Delft University of Technology, Reactor Institute Delft, Mekelweg 15, 2629 JB Delft (Netherlands); Harbin Engineering University, Nantong Street 145, 150001 Harbin (China); Kloosterman, Jan Leen, E-mail: j.l.kloosterman@tudelft.nl [Delft University of Technology, Reactor Institute Delft, Mekelweg 15, 2629 JB Delft (Netherlands)

2014-02-15

Highlights: • Composite-rod fuel blocks are proposed for a small block-type HTR. • An axial separation of fuel compacts is the most important feature. • Three patterns are presented to analyse the effects of the spatial distribution. • The spatial distribution has a large influence on the neutron spectrum. • Composite-rod fuel blocks reach a reactivity swing less than 4%. - Abstract: The U-Battery is a small long-life high temperature gas-cooled reactor (HTR) with power of 20 MWth. In order to increase its lifetime and diminish its reactivity swing, the concept of composite-rod fuel blocks with uranium and thorium was investigated. Composite-rod fuel blocks feature a specific axial separation between UO{sub 2} and ThO{sub 2} compacts in fuel rods. The design parameters, investigated by SCALE 6, include the number and spatial distribution of fuel compacts within the rods, the enrichment of uranium, the radii of fuel kernels and fuel compacts, and the packing fractions of uranium and thorium TRISO particles. The analysis shows that a lower moderation ratio and a larger inventory of heavy metals results in a lower reactivity swing. The optimal atomic carbon-to-heavy metal ratio depends on the mass fraction of U-235 and is commonly in the 160–200 range. The spatial distribution of the fuel compacts within the fuel rods has a large influence on the energy spectrum in each fuel compact and thus on the beginning-of-life reactivity and the reactivity swing. At end-of-life, the differences caused by the spatial distribution of the fuel compacts are smaller due to the fissions of U-233 in the ThO{sub 2} fuel compacts. This phenomenon enables to design fuel blocks with a very low reactivity swing, down to less than 4% in a 10-year lifetime. Among three types of thorium fuelled U-Battery blocks, the composite-rod fuel block achieves the highest end-of-life reactivity and the lowest reactivity swing.

A portable system powered with hydrogen and one single air-breathing PEM fuel cell

International Nuclear Information System (INIS)

Fernández-Moreno, J.; Guelbenzu, G.; Martín, A.J.; Folgado, M.A.; Ferreira-Aparicio, P.; Chaparro, A.M.

2013-01-01

Highlights: • A portable system based on hydrogen and single air breathing PEM fuel cell. • Control electronics designed for low single cell voltage (0.5–0.8 V). • Forced air convection and anode purging required to help water management. • Application consisting of a propeller able to display a luminous message. • Up to 20 h autonomy with continuous 1.1 W consumption, using 1 g H 2 . - Abstract: A portable system for power generation based on hydrogen and a single proton exchange membrane fuel cell (PEMFC) has been built and operated. The fuel cell is fed in the anode with hydrogen stored in a metal hydrides cartridge, and in the cathode with oxygen from quiescent ambient air (‘air breathing’). The control electronics of the system performs DC–DC conversion from the low voltage (0.5–0.8 V) and high current output (200–300 mA cm −2 ) of the single fuel cell, up to 3.3 V to power an electronic application. System components assist fuel cell operation, including an electronic valve for anode purging, a fan in front of the open cathode, two supercapacitors for auxiliary power requirements, four LED lights, and a display screen. The influence of the system components on fuel cell behaviour is analyzed. The cathode fan and anodic purging help excess water removal from the electrodes leading to steadier cell response at the expense of extra power consumption. The power system is able to provide above 1 W DC electricity to an external application during 20 h using 1 g of H 2 . An application consisting of a propeller able to display a luminous message is chosen to test system. It is shown that one single air breathing PEM fuel cell powered with hydrogen may provide high energy density and autonomy for portable applications

A compact seven switches topology and reduced DC-link capacitor size for single-phase stand-alone PV system with hybrid energy storages

DEFF Research Database (Denmark)

Liu, Xiong; Wang, Peng; Loh, Poh Chiang

2011-01-01

Single-phase stand-alone PV system is suitable for household applications in remote area. Hybrid battery/ultra-capacitor energy storage can reduce charge and discharge cycles and avoid deep discharges of battery. This paper proposes a compact seven switches structure for stand-alone PV system......, which otherwise needs nine switches configuration, inclusive of one switch for boost converter, four switches for single-phase inverter and four switches for two DC/DC converters of battery and ultra-capacitor. It is well-known that a bulky DC-link capacitor is always required to absorb second......-order harmonic current caused by single-phase inverter. In the proposed compact topology, a small size DC-link capacitor can achieve the same function through charging/discharging control of ultra-capacitor to mitigate second-order ripple current. Simulation results are provided to validate the effectiveness...

Flexibility of ADS for minor actinides transmutation in different two-stage PWR-ADS fuel cycle scenarios

International Nuclear Information System (INIS)

Zhou, Shengcheng; Wu, Hongchun; Zheng, Youqi

2018-01-01

Highlights: •ADS reloading scheme is optimized to raise discharge burnup and lower reactivity loss. •ADS is flexible to be combined with various pyro-chemical reprocessing technologies. •ADS is flexible to transmute MAs from different spent PWR fuels. -- Abstract: A two-stage Pressurized Water Reactor (PWR)-Accelerator Driven System (ADS) fuel cycle is proposed as an option to transmute minor actinides (MAs) recovered from the spent PWR fuels in the ADS system. At the second stage, the spent fuels discharged from ADS are reprocessed by the pyro-chemical process and the recovered actinides are mixed with the top-up MAs recovered from the spent PWR fuels to fabricate the new fuels used in ADS. In order to lower the amount of nuclear wastes sent to the geological repository, an optimized scattered reloading scheme for ADS is proposed to maximize the discharge burnup and lower the burnup reactivity loss. Then the flexibility of ADS for MA transmutation is evaluated in this research. Three aspects are discussed, including: different cooling time of spent ADS fuels before reprocessing, different reprocessing loss of spent ADS fuels, and different top-up MAs recovered from different kinds of spent PWR fuels. The ADS system is flexible to be combined with various pyro-chemical reprocessing technologies with specific spent fuels cooling time and unique reprocessing loss. The reduction magnitudes of the long-term decay heat and radiotoxicity of MAs by transmutation depend on the reprocessing loss. The ADS system is flexible to transmute MAs recovered from different kinds of spent PWR fuels, regardless of UOX or MOX fuels. The reduction magnitudes of the long-term decay heat and radiotoxicity of different MAs by transmutation stay on the same order.

Saturn V First Stage S-1C LOX Fuel Tanks

Science.gov (United States)

1960-01-01

This photograph shows the Saturn V assembled LOX (Liquid Oxygen) and fuel tanks ready for transport from the Manufacturing Engineering Laboratory at Marshall Space Flight Center in Huntsville, Alabama. The tanks were then shipped to the launch site at Kennedy Space Center for a flight. The towering 363-foot Saturn V was a multi-stage, multi-engine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams.

Process for the production of fuel combined articles for addition in block shaped high temperature fuel elements

International Nuclear Information System (INIS)

Hrovat, M.; Rachor, L.

1976-01-01

There is provided a process for the production of fuel compacts consisting of an isotropic, radiation-resistant graphite matrix of good heat conductivity having embedded therein coated fuel and/or fertile particles for insertion into high temperature fuel elements by providing the coated fuel and/or fertile particles with an overcoat of molding mixture consisting of graphite powder and a thermoplastic resin binder. The particles after the overcoating are provided with hardener and lubricant only on the surface and subsequently are compressed in a die heated to a constant temperature of about 150 0 C, hardened and discharged therefrom as finished compacts

Quantification of TRISO fuel heterogeneity effects in HTGR lattice physics calculations

International Nuclear Information System (INIS)

Perfetti, C. M.; Anghaie, S.; Dugan, E.; Marcille, T.

2010-01-01

A large number of LEU-MHR fuel compact models were generated with randomly distributed TRISO particle fuel and were simulated using MCNP5, and it was determined how several neutronic parameters, including k-infinite, the thermal and fast diffusion coefficients, and the four factors, varied across the randomly-generated cases. A sensitivity study was also performed to determine how the four factors depend on the definition of the thermal energy group. Values of k-infinite for the cases had a sample standard deviation of 248 pcm and were found to follow an approximately normal distribution about the mean value of k-infinite. Although all of the four factors were found to have similar sample standard deviations, the resonance escape probability was found to be the most variable parameter with a sample relative standard deviation between 0.07% and 0.08%. HTGR fuel compact homogenization methods typically examine only one reference fuel compact that contains a uniform distribution of TRISO particles, but in reality the TRISO particles are randomly distributed throughout the fuel compact. Thus, the neutronic parameters for actual fuel compacts differ randomly from those in the reference model. To license next-generation High-Temperature Gas Reactors engineers must quantify all uncertainties of the design and this random variation in neutron parameters is a previously unmeasured quantity; this study measures this uncertainty by examining the variation in k-infinite for HTGR fuel compact models with randomly distributed TRISO fuel. (authors)

System and method for single-phase, single-stage grid-interactive inverter

Science.gov (United States)

Liu, Liming; Li, Hui

2015-09-01

The present invention provides for the integration of distributed renewable energy sources/storages utilizing a cascaded DC-AC inverter, thereby eliminating the need for a DC-DC converter. The ability to segment the energy sources and energy storages improves the maintenance capability and system reliability of the distributed generation system, as well as achieve wide range reactive power compensation. In the absence of a DC-DC converter, single stage energy conversion can be achieved to enhance energy conversion efficiency.

Strategies and limits in multi-stage single-point incremental forming

DEFF Research Database (Denmark)

Skjødt, Martin; Silva, M.B.; Martins, P. A. F.

2010-01-01

paths. The results also reveal that the sequence of multi-stage forming has a large effect on the location of strain points in the principal strain space. Strain paths are linear in the first stage and highly non-linear in the subsequent forming stages. The overall results show that the experimentally......Multi-stage single-point incremental forming (SPIF) is a state-of-the-art manufacturing process that allows small-quantity production of complex sheet metal parts with vertical walls. This paper is focused on the application of multi-stage SPIF with the objective of producing cylindrical cups......-limit curves and fracture forming-limit curves (FFLCs), numerical simulation, and experimentation, namely the evaluation of strain paths and fracture strains in actual multi-stage parts. Assessment of numerical simulation with experimentation shows good agreement between computed and measured strain and strain...

Vibrational compacting of UO{sub 2} samples in the cladding; Vibraciono kompaktiranje uzoraka UO{sub 2} u zastitnoj kosuljici

Energy Technology Data Exchange (ETDEWEB)

Ristic, M M [Institute of Nuclear Sciences Vinca, Laboratorija za reaktorske materijale, Beograd (Serbia and Montenegro)

1962-12-15

Vibrational compacting was considered as a feasible method for fuel element fabrication. This report describes calibration of the vibrational compacting device. Vibrational compacting of UO{sub 2} was investigated. Obtained densities were not higher than 42% of the theoretical value, i.e. 70% of the possible compacting density. Influence of frequency, acceleration, power and time on the compacted samples was tested. Optimal conditions for UO{sub 2} compacting were as follows: frequency range from 2500 - 4000 Hz; acceleration range from 40 - 100 Hz; maximum power; time of compacting {approx} 5 min. Comparative evaluation of UO{sub 2} and SiO{sub 2} powders was done in order to improve the future development of this method for fabrication of fuel elements.

Evaluation of an automated single-channel sleep staging algorithm

Directory of Open Access Journals (Sweden)

Wang Y

2015-09-01

Full Text Available Ying Wang,1 Kenneth A Loparo,1,2 Monica R Kelly,3 Richard F Kaplan1 1General Sleep Corporation, Euclid, OH, 2Department of Electrical Engineering and Computer Science, Case Western Reserve University, Cleveland, OH, 3Department of Psychology, University of Arizona, Tucson, AZ, USA Background: We previously published the performance evaluation of an automated electroencephalography (EEG-based single-channel sleep–wake detection algorithm called Z-ALG used by the Zmachine® sleep monitoring system. The objective of this paper is to evaluate the performance of a new algorithm called Z-PLUS, which further differentiates sleep as detected by Z-ALG into Light Sleep, Deep Sleep, and Rapid Eye Movement (REM Sleep, against laboratory polysomnography (PSG using a consensus of expert visual scorers. Methods: Single night, in-lab PSG recordings from 99 subjects (52F/47M, 18–60 years, median age 32.7 years, including both normal sleepers and those reporting a variety of sleep complaints consistent with chronic insomnia, sleep apnea, and restless leg syndrome, as well as those taking selective serotonin reuptake inhibitor/serotonin–norepinephrine reuptake inhibitor antidepressant medications, previously evaluated using Z-ALG were re-examined using Z-PLUS. EEG data collected from electrodes placed at the differential-mastoids (A1–A2 were processed by Z-ALG to determine wake and sleep, then those epochs detected as sleep were further processed by Z-PLUS to differentiate into Light Sleep, Deep Sleep, and REM. EEG data were visually scored by multiple certified polysomnographic technologists according to the Rechtschaffen and Kales criterion, and then combined using a majority-voting rule to create a PSG Consensus score file for each of the 99 subjects. Z-PLUS output was compared to the PSG Consensus score files for both epoch-by-epoch (eg, sensitivity, specificity, and kappa and sleep stage-related statistics (eg, Latency to Deep Sleep, Latency to REM

Numerical model of a thermoelectric generator with compact plate-fin heat exchanger for high temperature PEM fuel cell exhaust heat recovery

DEFF Research Database (Denmark)

Xin, Gao; Andreasen, Søren Juhl; Chen, Min

2012-01-01

on a finite-element approach. On each discretized segment, fluid properties, heat transfer process and TEG performance are locally calculated for higher model precision. To benefit both the system design and fabrication, the way to model TEG modules is herein reconsidered; a database of commercialized compact......This paper presents a numerical model of an exhaust heat recovery system for a high temperature polymer electrolyte membrane fuel cell (HTPEMFC) stack. The system is designed as thermoelectric generators (TEGs) sandwiched in the walls of a compact plate-fin heat exchanger. Its model is based...... plate-fin heat exchangers is adopted. Then the model is validated against experimental data and the main variables are identified by means of a sensitivity analysis. Finally, the system configuration is optimized for recovering heat from the exhaust gas. The results exhibit the crucial importance...

Use of skin stretchers for single-stage bilateral mastectomies in a dog and a cat.

Science.gov (United States)

Miyazaki, Yuta; Aikawa, Takeshi; Shimatsu, Taichi; Nishimura, Masaaki; Sadahiro, Shigeo

2018-04-01

To describe the application of skin stretchers for closure of single-stage bilateral mastectomies in a dog and a cat. Clinical case report. A 12-year-old intact female Miniature Dachshund and a 13-year-old spayed female domestic short-hair cat. Skin stretchers were applied to the site of the skin adjacent to mammary glands for 2-4 days before surgery. Cable tension was adjusted every 6-8 hours to elongate the skin and to achieve primary closure of single-stage bilateral mastectomy without tension. Wound closure after single-stage bilateral mastectomy was achieved without tension or major complication in both animals. Use of skin stretchers allows primary closure of single-stage bilateral mastectomy in dogs and cats. © 2017 The American College of Veterinary Surgeons.

Physiological differentiation within a single-species biofilm fueled by serpentinization.

Science.gov (United States)

Brazelton, William J; Mehta, Mausmi P; Kelley, Deborah S; Baross, John A

2011-01-01

Carbonate chimneys at the Lost City hydrothermal field are coated in biofilms dominated by a single phylotype of archaea known as Lost City Methanosarcinales. In this study, we have detected surprising physiological complexity in single-species biofilms, which is typically indicative of multispecies biofilm communities. Multiple cell morphologies were visible within the biofilms by transmission electron microscopy, and some cells contained intracellular membranes that may facilitate methane oxidation. Both methane production and oxidation were detected at 70 to 80°C and pH 9 to 10 in samples containing the single-species biofilms. Both processes were stimulated by the presence of hydrogen (H(2)), indicating that methane production and oxidation are part of a syntrophic interaction. Metagenomic data included a sequence encoding AMP-forming acetyl coenzyme A synthetase, indicating that acetate may play a role in the methane-cycling syntrophy. A wide range of nitrogen fixation genes were also identified, many of which were likely acquired via lateral gene transfer (LGT). Our results indicate that cells within these single-species biofilms may have differentiated into multiple physiological roles to form multicellular communities linked by metabolic interactions and LGT. Communities similar to these Lost City biofilms are likely to have existed early in the evolution of life, and we discuss how the multicellular characteristics of ancient hydrogen-fueled biofilm communities could have stimulated ecological diversification, as well as unity of biochemistry, during the earliest stages of cellular evolution. Our previous work at the Lost City hydrothermal field has shown that its carbonate chimneys host microbial biofilms dominated by a single uncultivated "species" of archaea. In this paper, we integrate evidence from these previous studies with new data on the metabolic activity and cellular morphology of these archaeal biofilms. We conclude that the archaeal biofilm

The single SNR fuel assembly container (ESBB) to transport unirradiated SNR 300 fuel assemblies

International Nuclear Information System (INIS)

Hilbert, F.; Hottenrott, G.

1998-01-01

In this paper a new type B(U) package design is presented. The Single SNR Fuel Assembly Container (ESBB) is designed for the transport and storage of a single SNR 300 fuel assembly. This package is the main component for the future interim storage of the fuel assemblies in heavy storage casks. Its benefits are that it is compatible with the Category I transport system of Nuclear Cargo + Service NCS) used in Germany and that it can be easily handled at the current storage locations as well as in an interim storage facility. In total 205 fuel assemblies are currently stored in Hanau, Germany and Dounreay, U.K. Former studies have shown, that heavy transport and storage casks can be handled there only with considerable efforts. But the required category I transport to an interim storage is not reasonably feasible. To overcome these problems the ESBB was designed. It consists of a stainless steel tube with welded bottom, a welded plug as closure system and shock absorbers 26 packages at maximum can be transported in one batch with the NCS security vehicle. The safety analysis shows that the package complies with IAEA 1996. Standard calculations methods and computer codes like HEATING 7.2 (Childs 1993) have been used for the analysis. Criticality safety assessment is based on conservative assumptions as required in IAEA 1996. Drop tests carried out by BAM will be used to verify the design. These tests are scheduled for mid 1998. For the validation of the design prototypes have already been manufactured. Handling tests show that the design complies with the requirements. Preliminary drop tests show that the certification drop tests will be passed positively. (authors)

Advanced air staging techniques to improve fuel flexibility, reliability and emissions in fluidized bed co-combustion

Energy Technology Data Exchange (ETDEWEB)

Aamand, Lars-Erik; Leckner, Bo [Chalmers Technical Univ., Goeteborg (Sweden); Luecke, Karsten; Werther, Joachim [Technical Univ. of Hamburg-Harburg (Germany)

2001-12-01

A joint research project between the Technical University of Hamburg-Harburg and Chalmers Technical University. For operation under co-combustion the following results should be considered: The high ash content of the sewage sludge results in significantly increased ash flows. Although high alkali metal concentrations are found in the sewage sludge ash, no critical concentrations were reached and tendencies to fouling were not observed. The trace metal input rises with increased sludge fraction. However, emissions of metal compounds were well below legal limits. The trace metals tend to accumulate on the fly ash. In general, very low fuel nitrogen conversions to NO and N{sub 2}O of 2 - 4 % are achievable. With coal as a base fuel alternative air staging with secondary air supply after solids separation attains even lower NO emissions than normal staging without strongly affecting CO and SO{sub 2} emissions. Alternative staging also reduces N{sub 2}O emissions. An optimum for the excess air ratio in the riser of 1.05 was found for a total excess air ratio of 1.2. The higher the volatile content of the fuel is, the less effective the NO reduction due to air staging becomes. The measurements suggest that the optimum gas residence time regarding the emissions in CFB combustors is around 6 to 7 s. These times are achieved in commercial scale plants due to their large cyclones that perhaps partly can replace a large afterburner chamber. The circulating fluidized bed boiler can be operated in a very flexible way with various fuel mixtures up to an energy fraction of sludge of 25% without exceeding legal emission limits.

Compaction of Ti–6Al–4V powder using high velocity compaction technique

International Nuclear Information System (INIS)

Khan, Dil Faraz; Yin, Haiqing; Li, He; Qu, Xuanhui; Khan, Matiullah; Ali, Shujaat; Iqbal, M. Zubair

2013-01-01

Highlights: • We compacted Ti–6Al–4V powder by HVC technique. • As impact force rises up, the green density of the compacts increases gradually. • At impact force 1.857 kN relative sintered density of the compacts reaches 99.88%. • Spring back of the green compact’s decreases gradually with increasing impact force. • Mechanical properties of the samples increases with increasing impact force. - Abstract: High velocity compaction technique was applied to the compaction of pre-alloyed, hydride–dehydride Ti–6Al–4V powder. The powder was pressed in single stroke with a compaction speed of 7.10–8.70 ms −1 . When the speed was 8.70 ms −1 , the relative density of the compacts reaches up to 85.89% with a green density of 3.831 g cm −3 . The green samples were sintered at 1300 °C in Ar-gas atmosphere. Scanning electron microscope (SEM) was used to examine the surface of the sintered samples. Density and mechanical properties such as Vickers micro hardness and bending strength of the powder samples were investigated. Experimental results indicated that with the increase in impact force, the density and mechanical properties of the compacts increased. The sintered compacts exhibited a maximum relative density of 99.88% with a sintered density of 4.415 g cm −3 , hardness of 364–483 HV and the bending strength in the range of 103–126.78 MPa. The springback of the compacts decreased with increasing impact force

Near-optimal operation of dual-fuel launch vehicles

International Nuclear Information System (INIS)

Ardema, M.D.; Chou, H.C.; Bowles, J.V.

1994-01-01

Current studies of single-stage-to-orbit (SSTO) launch vehicles are focused on all-rocket propulsion systems. One option for such vehicles is the use of dual-fuel (liquid hydrocarbon and liquid hydrogen (LH 2 )), for a portion of the mission. As compared with LH 2 , hydrocarbon fuel has higher density and produces higher thrust-to-weight, but has lower specific impulse. The advantages of hydrocarbon fuel are important early in the ascent trajectory, and its use may be expected to lead to reduced vehicle size and weight. Because LH 2 is also needed for cooling purposes, in the early portion of the trajectory both fuels must be burned simultaneously. Later in the ascent, when vehicle weight is lower, specific impulse is the key parameter, indicating single-fuel LH 2 use

Fuel loads and fuel type mapping

Science.gov (United States)

Chuvieco, Emilio; Riaño, David; Van Wagtendonk, Jan W.; Morsdof, Felix; Chuvieco, Emilio

2003-01-01

Correct description of fuel properties is critical to improve fire danger assessment and fire behaviour modeling, since they guide both fire ignition and fire propagation. This chapter deals with properties of fuel that can be considered static in short periods of time: biomass loads, plant geometry, compactness, etc. Mapping these properties require a detail knowledge of vegetation vertical and horizontal structure. Several systems to classify the great diversity of vegetation characteristics in few fuel types are described, as well as methods for mapping them with special emphasis on those based on remote sensing images.

The efficacy of single-stage open intramedullary nailing of neglected femur fractures.

Science.gov (United States)

Boopalan, P R J V C; Sait, Azad; Jepegnanam, Thilak Samuel; Matthai, Thomas; Varghese, Viju Daniel

2014-02-01

Neglected femur fractures are not rare in the developing world. Treatment options include single-stage open reduction and intramedullary nailing, or open release, skeletal traction, and then second-stage open intramedullary nailing, with bone grafting. Single-stage procedures have the potential advantage of avoiding neurovascular complications secondary to acute lengthening, but they require a second operation, with potentially increased resource use and infection risk. We sought to determine the (1) likelihood of union, (2) complications and reoperations, and (3) functional results with single-stage open intramedullary nailing without bone grafting in patients with neglected femur fractures. Between January 2003 and December 2007, 17 consecutive patients presented to our practice with neglected femoral shaft fractures. All were treated with single-stage nailing without bone grafting. There were 15 men and two women with a median age of 27 years. The average time from fracture to treatment was 13 weeks (range, 4-44 weeks). Eleven patients underwent open nailing with interlocked nails and six were treated with cloverleaf Kuntscher nails. Patients were followed for a minimum of 6 months (mean, 33 months; range, 6-72 months). The mean preoperative ROM of the knee was 28° (range, 10°-150°) and femoral length discrepancy was 3.1 cm (range, 1-5 cm). All fractures united and the mean time to union was 16 weeks (range, 7-32 weeks). There were no neurologic complications secondary to acute lengthening. The mean postoperative ROM of the knee was 130° (range, 60°-150°). All patients were able to return to preinjury work. Sixteen patients regained their original femoral length. One-stage open intramedullary nailing of neglected femoral diaphyseal fractures without bone grafting was safe and effective, and obviated the need for a two-stage approach. Although the findings need to be replicated in larger numbers of patients, we believe this technique may be useful in

Agro-fuels, a cartography of stakes

International Nuclear Information System (INIS)

2008-09-01

This document proposes a dashboard of the main issues regarding agro-fuels. Nine sheets propose basic information and data on these issues: 1- agro-fuel production and consumption in the world (ethanol, vegetable oils, perspective for demand in the transport sector), 2- energy efficiency and greenhouse gas emissions (energy assessments and greenhouse effect of agro-fuels, discrepancies of results between first-generation European agro-fuels, case of agro-fuels produced in Southern countries), 3- needed surfaces in Europe (land use and cultivable areas for agro-fuel production in Europe and in France, competition between food and energy crops), 4- deforestation in the South (relationship between agriculture, deforestation and agro-fuels, between deforestation and greenhouse gas emissions), 5- impacts on biodiversity (use of pesticides and fertilizers, large scale cultivations and single-crop farming, cultivation of fallow land and permanent meadows, deforestation in the South, relationship between agro-fuels and GMOs), 6- impacts on water, soil and air (water quality and availability, soil erosion, compaction and fertility loss, air quality), 7- food-related and social stakes (issue of food security, social impacts of agro-fuel production with pressure on family agriculture and issues of land property), 8- public supports and economic efficiency (public promotion of agro-fuels, agro-fuel and oil prices, assessment of the 'avoided' CO 2 ton), and 9- perspectives for second-generation agro-fuels (definitions and processes, benefits with respect to first-generation fuels, possible impacts on the environment, barriers to their development)

The CIT [compact ignition tokamak] pellet injection system: Description and supporting research and development

International Nuclear Information System (INIS)

Gouge, M.J.; Combs, S.K.; Fisher, P.W.; Milora, S.L.

1989-01-01

The Compact Ignition Tokamak (CIT) will use an advance, high-velocity pellet injection system to achieve and maintain ignited plasmas. Two pellet injectors are provided: a moderate-velocity (1-to 1.5-km/s), single-stage pneumatic injector with high reliability and a high-velocity (4- to 5-km/s), two-stage pellet injector that uses frozen hydrogenic pellets encased in sabots. Both pellet injectors are qualified for operation with tritium feed gas. Issues such as performance, neutron activation of injector components, maintenance, design of the pellet injection vacuum line, gas loads to the reprocessing system, and equipment layout are discussed. Results and plans for supporting research and development (R and D) in the areas of tritium pellet fabrication and high-velocity, repetitive two-stage pneumatic injectors are presented. 7 refs., 4 figs., 2 tabs

Irradiation testing of coated particle fuel at Hanaro

International Nuclear Information System (INIS)

Goo Kim, Bong; Sung Cho, Moo; Kim, Yong Wan

2014-01-01

TRISO-coated particle fuel is developing to support development of VHTR in Korea. From August 2013, the first irradiation testing of coated particle fuel was begun to demonstrate and qualify TRISO fuel for use in VHTR in the HANARO at KAERI. This experiment is currently undergoing under the atmosphere of a mixed inert gas without on-line temperature monitoring and control combined with on-line fission product monitoring of the sweep gas. The irradiation device contains two test rods, one contains nine fuel compacts and the other five compacts and eight graphite specimens. Each compact has 263 coated particles. After a peak burn-up of about 4 at% and a peak fast neutron fluence of about 1.7 x 10 21 n/cm 2 , PIE will be carried out at KAERI's Irradiated Material Examination Facility. This paper is described characteristics of coated particle fuel, the design of test rod and irradiation device for coated particle fuel, discusses the technical results for irradiation testing at HANARO. (authors)

PIE on Safety-Tested Loose Particles from Irradiated Compact 4-4-2

Energy Technology Data Exchange (ETDEWEB)

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

2016-04-01

Post-irradiation examination (PIE) is being performed in support of tristructural isotropic (TRISO) coated particle fuel development and qualification for High Temperature Gas-cooled Reactors (HTGRs). This work is sponsored by the Department of Energy Office of Nuclear Energy (DOE-NE) through the Advanced Reactor Technologies (ART) Office under the Advanced Gas Reactor Fuel Development and Qualification (AGR) Program. The AGR-1 experiment was the first in a series of TRISO fuel irradiation tests initiated in 2006. The AGR-1 TRISO particles and fuel compacts were fabricated at Oak Ridge National Laboratory (ORNL) in 2006 using laboratory-scale equipment and irradiated for 3 years in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) to demonstrate and evaluate fuel performance under HTGR irradiation conditions. Post-irradiation examination was performed at INL and ORNL to study how the fuel behaved during irradiation, and to test fuel performance during exposure to elevated temperatures at or above temperatures that could occur during a depressurized conduction cooldown event. This report summarizes safety testing and post-safety testing PIE conducted at ORNL on loose particles extracted from irradiated AGR-1 Compact 4-4-2.

The early stages of oxidation of magnesium single crystal surfaces

International Nuclear Information System (INIS)

Hayden, B.E.; Schweizer, E.; Koetz, R.; Bradshaw, A.M.

1981-01-01

The early stages of oxidation of Mg(001) and Mg(100) single crystal surfaces at 300 K have been investigated by LEED, ELS, work function and ellipsometric measurements. A sharp decrease in work function on both surfaces during the first 12 L exposure indicates the incorporation of oxygen in the earliest stages of the interaction. The incorporated oxygen on Mg(001) gives rise to a broadening of the integral order LEED spots for an exposure 3 L. (orig.)

Design of single piece sabot for a single stage gas gun

Science.gov (United States)

Vemparala, Vignesh; Mathew, Arun Tom; Rao Koka, Tirumala

2017-11-01

Single piece sabot is a vital part in single stage gas guns for impact testing in aerospace industries. Depending on the type of projectile used the design of sabot varies to accommodate the testing equipment. The velocity of the projectile exiting the barrel is dependent on the material and shape of the sabot used. The material selected for the design of sabot is rigid polyurethane foam, due to their low elastic modulus and low density. Two samples of rigid PU foam is taken and tests are performed to get their exact material properties. These properties are incorporated in numerical simulation to determine the best fit for practical use. Since the PU foams has a wide range of porosity which plays a prominent role in deciding the exit velocity and accuracy of the projectile coming out of the barrel. By optimisation, to the best suitable material sample can be determined.

Bifunctional electrodes for unitised regenerative fuel cells

International Nuclear Information System (INIS)

Altmann, Sebastian; Kaz, Till; Friedrich, Kaspar Andreas

2011-01-01

Research highlights: → Different oxygen electrode configurations for the operation in a unitised reversible fuel cell were tested. → Polarisation curves and EIS measurements were recorded. → The mixture of catalysts performs best for the present stage of electrode development. → Potential improvements for the different compositions are discussed. - Abstract: The effects of different configurations and compositions of platinum and iridium oxide electrodes for the oxygen reaction of unitised regenerative fuel cells (URFC) are reported. Bifunctional oxygen electrodes are important for URFC development because favourable properties for the fuel cell and the electrolysis modes must be combined into a single electrode. The bifunctional electrodes were studied under different combinations of catalyst mixtures, multilayer arrangements and segmented configurations with single catalyst areas. Distinct electrochemical behaviour was observed for both modes and can be explained on the basis of impedance spectroscopy. The mixture of both catalysts performs best for the present stage of electrode development. Also, the multilayer electrodes yielded good results with the potential for optimisation. The influence of ionic and electronic resistances on the relative performance is demonstrated. However, penalties due to cross currents in the heterogeneous electrodes were identified and explained by comparing the performance curves with electrodes composed of a single catalyst. Potential improvements for the different compositions are discussed.

Nitrite reduction and methanogenesis in a single-stage UASB reactor.

Science.gov (United States)

Borges, L I; López-Vazquez, C M; García, H; van Lier, J B

2015-01-01

In this study, nitrite reduction and methanogenesis in a single-stage upflow anaerobic sludge blanket (UASB) reactor was investigated, using high-strength synthetic domestic wastewater as substrate. To assess long-term effects and evaluate the mechanisms that allow successful nitrite reduction and methanogenesis in a single-stage UASB, sludge was exposed to relatively high nitrite loading rates (315 ± 13 mgNO(2)(-)-N/(l.d)), using a chemical oxygen demand (COD) to nitrogen ratio of 18 gCOD/gNO(2)(-)-N, and an organic loading rate of 5.4 ± 0.2 gCOD/(l.d). In parallel, the effects of sludge morphology on methanogenesis inhibition were studied by performing short-term batch activity tests at different COD/NO(2)(-)-N ratios with anaerobic sludge samples. In long-term tests, denitrification was practically complete and COD removal efficiency did not change significantly after nitrite addition. Furthermore, methane production only decreased by 13%, agreeing with the reducing equivalents requirement for complete NO(2)(-) reduction to N₂. Apparently, the spatial separation of denitrification and methanogenesis zones inside the UASB reactor allowed nitrite reduction and methanogenesis to occur at the same moment. Batch tests showed that granules seem to protect methanogens from nitrite inhibition, probably due to transport limitations. Combined COD and N removal via nitrite in a single-stage UASB reactor could be a feasible technology to treat high-strength domestic wastewater.

Compact Single-Layer Traveling-Wave Antenna DesignUsing Metamaterial Transmission Lines

Science.gov (United States)

Alibakhshikenari, Mohammad; Virdee, Bal Singh; Limiti, Ernesto

2017-12-01

This paper presents a single-layer traveling-wave antenna (TWA) that is based on composite right/left-handed (CRLH)-metamaterial (MTM) transmission line (TL) structure, which is implemented by using a combination of interdigital capacitors and dual-spiral inductive slots. By embedding dual-spiral inductive slots inside the CRLH MTM-TL results in a compact TWA. Dimensions of the proposed CRLH MTM-TL TWA is 21.5 × 30.0 mm2 or 0.372λ0 × 0.520λ0 at 5.2 GHz (center frequency). The fabricated TWA operates over 1.8-8.6 GHz with a fractional bandwidth greater than 120%, and it exhibits a peak gain and radiation efficiency of 4.2 dBi and 81%, respectively, at 5 GHz. By avoiding the use of lumped components, via-holes or defected ground structures, the proposed TWA design is economic for mass production as well as easy to integrate with wireless communication systems.

Experimental determination of thermal conductivity and gap conductance of fuel rod for HTGR

International Nuclear Information System (INIS)

Kikuchi, Teruo; Iwamoto, Kazumi; Ikawa, Katsuichi; Ishimoto, Kiyoshi

1985-01-01

The thermal conductivity of fuel compacts and the gap conductance between the fuel compact and the graphite sleeve in fuel rods for a high-temperature gas-cooled reactor (HTGR) were measured by the center heating method. These measurements were made as functions of volume percent particle loading and temperature for thermal conductivity and as functions of gap distance and gas composition for gap conductance. The thermal conductivity of fuel compacts decreases with increasing temperature and with increasing particle loading. The gap conductance increases with increasing temperature and decrease with increasing gap distance. A good gap conductance was observed with helium fill gas. It was seen that the gap conductance was dependent on the thermal conductivity of fill gas and conductance by radiation and could be neglected the conductance through solid-solid contact points of fuel compact and graphite sleeve. (author)

The nuclear fuel cycle

International Nuclear Information System (INIS)

Jones, P.M.S.

1987-01-01

This chapter explains the distinction between fissile and fertile materials, examines briefly the processes involved in fuel manufacture and management, describes the alternative nuclear fuel cycles and considers their advantages and disadvantages. Fuel management is usually divided into three stages; the front end stage of production and fabrication, the back end stage which deals with the fuel after it is removed from the reactor (including reprocessing and waste treatment) and the stage in between when the fuel is actually in the reactor. These stages are illustrated and explained in detail. The plutonium fuel cycle and thorium-uranium-233 fuel cycle are explained. The differences between fuels for thermal reactors and fast reactors are explained. (U.K.)

Performance of a methane-fueled single-cell SOFC stack at various levels of fuel utilization

International Nuclear Information System (INIS)

Ahmed, K.; Bolden, R.; Ramprakash and Foger, K.

1998-01-01

Fuel-gas mixtures representing 10 to 85% utilization of a methane-steam mixture at S/C=2 were fed to a single cell stack with a Ni-based anode at 875 deg C. Cell voltage and power output were recorded at current densities of 50 to 350 mA/cm 2 . The accompanying anode off-gas composition at some of these conditions were measured using on-line gas chromatograph and compared with the compositions predicted by a thermodynamic model based on the assumption of no carbon formation. Electrical losses were measured at a chosen current density at various levels of fuel utilization by the galvanostatic current-interruption technique. Cell voltage stability was monitored for up to 1000 h at two levels of fuel utilization. The stack performance was simulated using a mathematical model of the stack; the simulations were compared with the stack test data. Copyright (1998) Australasian Ceramic Society

Method and apparatus for dismantling and disposing of fuel assemblies

International Nuclear Information System (INIS)

Meuschke, R.E.; Schulties, J.R.

1985-01-01

This invention relates to apparatus and a method for dismantling, shearing, and compacting a fuel assembly frame skeleton. It uses an apparatus capable of hanging or being supported in the transfer canal of the spent fuel pit of the fuel handling building. This apparatus includes a bottom nozzle shear which is held under water to shear off the bottom nozzle and convey it to a scrap transfer bin. Then the remaining portion is brought to a skeleton compactor and shear, also held under water. The compacted skeleton is sheared into a number of smaller portions. After compacting and shearing, the individual portions are fed to the scrap transfer bin. The compacted and sheared skeleton assembly may be placed into a container that is adapted to hold four skeletons for off-site removal

Improvements in quality of as-manufactured fuels for high-temperature gas-cooled reactors

International Nuclear Information System (INIS)

Minato, Kazuo; Kikuchi, Hironobu; Tobita, Tsutomu; Fukuda, Kousaku; Kaneko, Mitsunobu; Suzuki, Nobuyuki; Yoshimuta, Shigeharu; Tomimoto, Hiroshi.

1997-01-01

The mechanisms of coating failure of the fuel particles for the high-temperature gas-cooled reactors during coating and compaction processes of the fuel fabrication were studied to determine a way to reduce the defective particle fraction of the as-manufactured fuels. Through the observation of the defective particles, it was found that the coating failure during the coating process was mainly caused by the strong mechanical shocks to the particles given by violent particle fluidization in the coater and by unloading and loading of the particles. The coating failure during the compaction process was probably related to the direct contact with neighboring particles in the fuel compacts. The coating process was improved by optimizing the mode of the particle fluidization and by developing the process without unloading and loading of the particles at intermediate coating process. The compaction process was improved by optimizing the combination of the pressing temperature and the pressing speed of the overcoated particles. Through these modifications of the fabrication process, the quality of the as-manufactured fuel compacts was improved outstandingly. (author)

Fuel rod simulator effects in flooding experiments single rod tests

International Nuclear Information System (INIS)

Nishida, M.

1984-09-01

The influence of a gas filled gap between cladding and pellet on the quenching behavior of a PWR fuel rod during the reflood phase of a LOCA has been investigated. Flooding experiments were conducted with a short length electrically heated single fuel rod simulator surrounded by glass housing. The gap of 0.05 mm width between the Zircaloy cladding and the internal Al 2 O 3 pellets of the rod was filled either wit helium or with argon to vary the radial heat resistance across the gap. This report presents some typical data and an evaluation of the reflood behavior of the fuel rod simulator used. The results show that the quench front propagates faster for increasing heat resistance in the gap between cladding and heat source of the rod. (orig.) [de

Advanced research reactor fuel development

Energy Technology Data Exchange (ETDEWEB)

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

2000-05-01

-plates will be conducted in the Advanced Test Reactor(ATR). 49 compacts with a uranium density of 8 gU/cc consist of 7 different atomized uranium-molybdenum alloy powders. The tensile strength increased and the elongation decreased with increasing the volume fraction of U-10Mo powders in dispersion fuel. The tensile strength was lower and elongation was larger in dispersion fuel using atomized U-10Mo powders than that using comminuted fuel powders. The green strength of the comminuted powder compacts was about twice as large as that of the atomized powder compacts. It is suggested that the compacting condition required to fabricate the atomized powder compacts is over the 350MPa. The comminuted irregular shaped particles and smaller particle size of fuel powders showed improved homogeneity of powder mixture. The homogeneity of powder mixtures increased to a minimum at approximately 0.10 wt% moisture and then decreased with moisture content.

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

International Nuclear Information System (INIS)

Harp, Jason M.; Demkowicz, Paul A.; Winston, Philip L.; Sterbentz, James W.

2014-01-01

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

Postirradiation examination of Peach Bottom HTGR Driver Fuel Element E06-01

International Nuclear Information System (INIS)

Dyer, F.F.; Wichner, R.P.; Martin, W.J.; Fairchild, L.L.; Kedl, R.J.; de Nordwall, H.J.

1976-04-01

The report presented describes the postirradiation examinations of driver fuel element E06-01, which had been irradiated an equivalent of 384 full-power days in Peach Bottom, Unit 1. The fuel element is described in detail and its temperature and irradiation service history briefly outlined. Results presented include: (1) visual observations; (2) critical dimensions of fuel compacts, sleeve, and spine; (3) axial distributions of gamma-emitting nuclides plus 3 H and 90 Sr; (4) radial distributions of these nuclides in the sleeve and spine at three axial locations in the fueled regions and three locations in the upper reflector; (5) metallographic examination of samples of fuel compact material; and (6) burnup determinations via radiochemical analyses at two compact locations

Durability testing of medium speed diesel engine components designed for operating on coal/water slurry fuel

Science.gov (United States)

McDowell, R. E.; Giammarise, A. W.; Johnson, R. N.

1994-01-01

Over 200 operating cylinder hours were run on critical wearing engine parts. The main components tested included cylinder liners, piston rings, and fuel injector nozzles for coal/water slurry fueled operation. The liners had no visible indication of scoring nor major wear steps found on their tungsten carbide coating. While the tungsten carbide coating on the rings showed good wear resistance, some visual evidence suggests adhesive wear mode was present. Tungsten carbide coated rings running against tungsten carbide coated liners in GE 7FDL engines exhibit wear rates which suggest an approximate 500 to 750 hour life. Injector nozzle orifice materials evaluated were diamond compacts, chemical vapor deposited diamond tubes, and thermally stabilized diamond. Based upon a total of 500 cylinder hours of engine operation (including single-cylinder combustion tests), diamond compact was determined to be the preferred orifice material.

Understanding and Mitigating Reservoir Compaction: an Experimental Study on Sand Aggregates

Science.gov (United States)

Schimmel, M.; Hangx, S.; Spiers, C. J.

2016-12-01

Fossil fuels continue to provide a source for energy, fuels for transport and chemicals for everyday items. However, adverse effects of decades of hydrocarbons production are increasingly impacting society and the environment. Production-driven reduction in reservoir pore pressure leads to a poro-elastic response of the reservoir, and in many occasions to time-dependent compaction (creep) of the reservoir. In turn, reservoir compaction may lead to surface subsidence and could potentially result in induced (micro)seismicity. To predict and mitigate the impact of fluid extraction, we need to understand production-driven reservoir compaction in highly porous siliciclastic rocks and explore potential mitigation strategies, for example, by using compaction-inhibiting injection fluids. As a first step, we investigate the effect of chemical environment on the compaction behaviour of sand aggregates, comparable to poorly consolidated, highly porous sandstones. The sand samples consist of loose aggregates of Beaujean quartz sand, sieved into a grainsize fraction of 180-212 µm. Uniaxial compaction experiments are performed at an axial stress of 35 MPa and temperature of 80°C, mimicking conditions of reservoirs buried at three kilometres depth. The chemical environment during creep is either vacuum-dry or CO2-dry, or fluid-saturated, with fluids consisting of distilled water, acid solution (CO2-saturated water), alkaline solution (pH 9), aluminium solution (pH 3) and solution with surfactants (i.e., AMP). Preliminary results show that compaction of quartz sand aggregates is promoted in a wet environment compared to a dry environment. It is inferred that deformation is controlled by subcritical crack growth when dry and stress corrosion cracking when wet, both resulting in grain failure and subsequent grain rearrangement. Fluids inhibiting these processes, have the potential to inhibit aggregate compaction.

Improving feeding powder distribution to the compaction zone in the roller compaction.

Science.gov (United States)

Yu, Mingzhe; Omar, Chalak; Schmidt, Alexander; Litster, James D; Salman, Agba D

2018-07-01

In the roller compaction process, powder flow properties have a significant influence on the uniformity of the ribbon properties. The objective of this work was to improve the powder flow in the feeding zone by developing novel feeding guiders which are located in the feeding zone close to the rollers in the roller compactor (side sealing system). Three novel feeding guiders were designed by 3D printing and used in the roller compactor, aiming to control the amount of powder passing across the roller width. The new feeding guiders were used to guide more powder to the sides between the rollers and less powder to the centre comparing to the original feeding elements. Temperature profile and porosity across the ribbon width indicated the uniformity of the ribbon properties. Using the novel feeding guiders resulted in producing ribbons with uniform temperature profile and porosity distribution across the ribbon width. The design of the feeding guiders contributed to improving the tensile strength of the ribbons produced from the compaction stage as well as reducing the fines produced from the crushing stage. Copyright © 2018 Elsevier B.V. All rights reserved.

Compaction of a Bed of Fragmentable Particles and Associated Acoustic Emission

International Nuclear Information System (INIS)

Hegron, L.; Sornay, P.; Favretto-Cristini, N.

2013-06-01

The nuclear fuel of light water power reactors are manufactured by powder metallurgy. This is also the method that is used for the production of fuels containing minor actinides that have high activity and long life. Given their radiotoxicity, it is necessary to simplify the manufacturing process to the maximum, limiting dissemination and retention of matter. In addition, the fuel must have a mostly open porosity. Implementation of particles of a few hundred micrometers and controlled cohesion could meet this dual objective. However, it should be ensured that the mechanical strength of compacts before sintering is sufficient without adding binder. The phenomena that occur during the manufacture of compact are thus analyzed and quantified. It is shown that only a portion of the particles breaks upon application of a stress up to 600 MPa and it is possible to detect this fragmentation by acoustic emission (AE). (authors)

Purifier-integrated methanol reformer for fuel cell vehicles

Science.gov (United States)

Han, Jaesung; Kim, Il-soo; Choi, Keun-Sup

We developed a compact, 3-kW, purifier-integrated modular reformer which becomes the building block of full-scale 30-kW or 50-kW methanol fuel processors for fuel cell vehicles. Our proprietary technologies regarding hydrogen purification by composite metal membrane and catalytic combustion by washcoated wire-mesh catalyst were combined with the conventional methanol steam-reforming technology, resulting in higher conversion, excellent quality of product hydrogen, and better thermal efficiency than any other systems using preferential oxidation. In this system, steam reforming, hydrogen purification, and catalytic combustion all take place in a single reactor so that the whole system is compact and easy to operate. Hydrogen from the module is ultrahigh pure (99.9999% or better), hence there is no power degradation of PEMFC stack due to contamination by CO. Also, since only pure hydrogen is supplied to the anode of the PEMFC stack, 100% hydrogen utilization is possible in the stack. The module produces 2.3 Nm 3/h of hydrogen, which is equivalent to 3 kW when PEMFC has 43% efficiency. Thermal efficiency (HHV of product H 2/HHV of MeOH in) of the module is 89% and the power density of the module is 0.77 kW/l. This work was conducted in cooperation with Hyundai Motor Company in the form of a Korean national project. Currently the module is under test with an actual fuel cell stack in order to verify its performance. Sooner or later a full-scale 30-kW system will be constructed by connecting these modules in series and parallel and will serve as the fuel processor for the Korean first fuel cell hybrid vehicle.

Casette for storage of spent fuel assemblies

International Nuclear Information System (INIS)

Ericsson, S.

1992-01-01

Describes a design of a casette for spent fuel storage in a fuelstorage pool. The new design, based on flexible spacers, allows the fuel assemblies to be packed more compact and the fuel storage pool used in a more economic way

Low grade bioethanol for fuel mixing on gasoline engine using distillation process

Science.gov (United States)

Abikusna, Setia; Sugiarto, Bambang; Suntoro, Dedi; Azami

2017-03-01

Utilization of renewable energy in Indonesia is still low, compared to 34% oil, 20% coal and 20% gas, utilization of energy sources for water 3%, geothermal 1%, 2% biofuels, and biomass 20%. Whereas renewable energy sources dwindling due to the increasing consumption of gasoline as a fuel. It makes us have to look for alternative renewable energy, one of which is bio ethanol. Several studies on the use of ethanol was done to the researchers. Our studies using low grade bio ethanol which begins with the disitillation independently utilize flue gas heat at compact distillator, produces high grade bio ethanol and ready to be mixed with gasoline. Stages of our study is the compact distillator design of the motor dynamic continued with good performance and emission testing and ethanol distilled. Some improvement is made is through the flue gas heat control mechanism in compact distillator using gate valve, at low, medium, and high speed engine. Compact distillator used is kind of a batch distillation column. Column design process using the shortcut method, then carried the tray design to determine the overall geometry. The distillation is done by comparing the separator with a tray of different distances. As well as by varying the volume of the feed and ethanol levels that will feed distilled. In this study, we analyzed the mixing of ethanol through variation between main jet and pilot jet in the carburetor separately interchangeably with gasoline. And finally mixing mechanism bio ethanol with gasoline improved with fuel mixer for performance.

Development of a compact bushing for NBI

Science.gov (United States)

de Esch, H. P. L.; Simonin, A.; Grand, C.; Lepetit, B.; Lemoine, D.; Márquez-Mijares, M.; Minea, T.; Caillault, L.; Seznec, B.; Jager, T.; Odic, E.; Kirkpatrick, M. J.; Teste, Ph.; Dessante, Ph.; Almaksour, K.

2017-08-01

Research into a novel type of compact bushing is being conducted through the HVIV (High Voltage holding In Vacuum) partnership between CEA-Cadarache1, GeePs-Centralesupélec4, LPGP3 and LCAR2. The bushing aims to concentrate the high electric field inside its interior, rather than in the vacuum tank. Hence the field emission current is also concentrated inside the bushing and it can be attempted to suppress this so-called dark current by conditioning the internal surfaces and by adding gas. LCAR have performed theoretical quantum mechanical studies of electron field emission and the role of adsorbates in changing the work function. LPGP studied the ionization of gas due to field emission current and the behavior of micro particles exposed to emissive electron current in the vacuum gap under high electric fields. Experiments at Geeps have clarified the role of surface conditioning in reducing the dark current. Geeps also found that adding low pressure nitrogen gas to the vacuum is much more effective than helium in reducing the field emission. An interesting observation is the growth of carbon structures after exposure of an electrode to the electric field. Finally, IRFM have performed experiments on a single stage test bushing that features a 36 cm high porcelain insulator and two cylindrical electrode surfaces in vacuum or low-pressure gas. Using 0.1 Pa N2 gas, the voltage holding exceeded 185 kV over a 40 mm "vacuum" gap without dark current. Above this voltage, exterior breakdowns occurred over the insulator, which was in air. The project will finish with the fabrication of a 2-stage compact bushing, capable to withstand 400 kV.

Single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation in surgical treatment for single-segment lumbar spinal tuberculosis

OpenAIRE

Zeng, Hao; Wang, Xiyang; Zhang, Penghui; Peng, Wei; Zhang, Yupeng; Liu, Zheng

2015-01-01

Objective: The aim of this study is to determine the feasibility and efficacy of surgical management of single-segment lumbar spinal tuberculosis (TB) by using single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation.Methods: Seventeen cases of single-segment lumbar TB were treated with single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reco...

Pre-irradiation testing of experimental fuel elements

International Nuclear Information System (INIS)

Basova, B.G.; Davydov, E.F.; Dvoretskij, V.G.; Ivanov, V.B.; Syuzev, V.N.; Timofeev, G.A.; Tsykanov, V.A.

1979-01-01

The problems of testing of experimental fuel elements of nuclear reactors on the basis of complex accountancy of the factors defining operating capacity of the fuel elements are considered. The classification of the parameters under control and the methods of initial technological testing, including testing of the fuel product, cladding and fished fuel element, is given. The requirements to the apparatus used for complex testing are formulated. One of the possible variants of representation of the information obtained in the form of the input certificate of a single fuel element under study is proposed. The processing flowsheet of the gathered information using the computer is given. The approach under consideration is a methodological basis of investigation of fuel element operating life at the testing stage of the experimental fuel elements

Compact reactor/ORC power source

International Nuclear Information System (INIS)

Meier, K.L.; Kirchner, W.L.; Willcutt, G.J.

1986-01-01

A compact power source that combines an organic Rankine Cycle (ORC) electric generator with a nuclear reactor heat source is being designed and fabricated. Incorporating existing ORC technology with proven reactor technology, the compact reactor/ORC power source offers high reliability while minimizing the need for component development. Thermal power at 125 kWt is removed from the coated particle fueled, graphite moderated reactor by heat pipes operating at 500 0 C. Outside the reactor vessel and connected to the heat pipes are vaporizers in which the toluene ORC working fluid is heated to 370 0 C. In the turbine-alternator-pump (TAP) combined-rotating unit, the thermal energy of the toluene is converted to 25 kWe of electric power. Lumped parameter systems analyses combined with a finite element thermal analysis have aided in the power source design. The analyses have provided assurance of reliable multiyear normal operation as well as full power operation with upset conditions, such as failed heat pipes and inoperative ORC vaporizers. Because of inherent high reliability, long life, and insensitivity to upset conditions, this power source is especially suited for use in remote, inaccessible locations where fuel delivery and maintenance costs are high. 10 refs

Practical Considerations Concerning the Interleaved Transition Mode Single-stage Ballast

DEFF Research Database (Denmark)

Teodorescu, Remus; Kjær, Søren Bækhøj; Munk-Nielsen, Stig

2002-01-01

The aim of this paper is to present a novel single-stage interleaved ballast focusing on practical design aspects like: key current expression, overall losses, harmonic analysis of the differential-mode EMI current and preheating ballast function. A new preheating method is also presented. A PSPICE...

A portable high-power diode laser-based single-stage ceramic tile grout sealing system

Science.gov (United States)

Lawrence, J.; Schmidt, M. J. J.; Li, L.; Edwards, R. E.; Gale, A. W.

2002-02-01

By means of a 60 W high-power diode laser (HPDL) and a specially developed grout material the void between adjoining ceramic tiles has been successfully sealed. A single-stage process has been developed which uses a crushed ceramic tile mix to act as a tough, inexpensive bulk substrate and a glazed enamel surface to provide an impervious surface glaze. The single-stage ceramic tile grout sealing process yielded seals produced in normal atmospheric conditions that displayed no discernible cracks and porosities. The single-stage grout is simple to formulate and easy to apply. Tiles were successfully sealed with power densities as low as 200 kW/ mm2 and at rates of up to 600 mm/ min. Bonding of the enamel to the crushed ceramic tile mix was identified as being primarily due to van der Waals forces and, on a very small scale, some of the crushed ceramic tile mix material dissolving into the glaze. In terms of mechanical, physical and chemical characteristics, the single-stage ceramic tile grout was found to be far superior to the conventional epoxy tile grout and, in many instances, matched and occasionally surpassed that of the ceramic tiles themselves. What is more, the development of a hand-held HPDL beam delivery unit and the related procedures necessary to lead to the commercialisation of the single-stage ceramic tile grout sealing process are presented. Further, an appraisal of the potential hazards associated with the use of the HPDL in an industrial environment and the solutions implemented to ensure that the system complies with the relevant safety standards are given.

Special issue on compact x-ray sources

Science.gov (United States)

Hooker, Simon; Midorikawa, Katsumi; Rosenzweig, James

2014-04-01

. New schemes for compact accelerators: laser- and beam-driven plasma accelerators; dielectric laser accelerators; THz accelerators. Latest results for compact accelerators. Target design and staging of advanced accelerators. Advanced injection and phase space manipulation techniques. Novel diagnostics: single-shot measurement of sub-fs bunch duration; measurement of ultra-low emittance. Generation and characterization of incoherent radiation: betatron and undulator radiation; Thomson/Compton scattering sources, novel THz sources. Generation and characterization of coherent radiation. Novel FEL simulation techniques. Advances in simulations of novel accelerators: simulations of injection and acceleration processes; simulations of coherent and incoherent radiation sources; start-to-end simulations of fifth generation light sources. Novel undulator schemes. Novel laser drivers for laser-driven accelerators: high-repetition rate laser systems; high wall-plug efficiency systems. Applications of compact accelerators: imaging; radiography; medical applications; electron diffraction and microscopy. Please submit your article by 15 May 2014 (expected web publication: winter 2014); submissions received after this date will be considered for the journal, but may not be included in the special issue.

Pressing device for producing compacts from source material in powder form in particular pulverized nuclear reactor fuel

International Nuclear Information System (INIS)

Heller, G.; Adelmann, M.; Konigs, W.; Wendorf, W.

1984-01-01

Pressing device for producing compacts from source material in powder form, in particular pulverized nuclear reactor fuel having a die-plate contained in platen and a bore associated with a ram, for receiving source material powder, a filling shoe, and a reservoir for powder connected by a hose to the filling shoe. The device is characterized by a passing wheel in the filling shoe as filling aid means; a tube containing a feedscrew disposed between the reservoir and hose as metering means; the reservoir having a bottom part with a can type place-on part with an opening eccentric to the axis; a coupling part and a cover part are placed on the open part of the can, these parts are also provided with a passageway to the feedscrew eccentric to the longitudinal axis

Single-staged uniportal VATS in the supine position for simultaneous bilateral primary spontaneous pneumothorax.

Science.gov (United States)

Kim, Kyung Soo

2017-05-15

Simultaneous bilateral primary spontaneous pneumothorax (SBPSP) is rare, but requires surgery on both sides, in patients with definite bilateral bullae to prevent life-threatening conditions. Recently, uniportal video-assisted thoracoscopic surgery (VATS) has been widely accepted as a less invasive technique for the treatment of pneumothorax. Thus, we introduced single-staged uniportal VATS technique in the supine position, for the management of two cases of SBPSP. A 17-year-old boy presented with bilateral spontaneous pneumothorax and he underwent single-staged uniportal VATS in the supine position. Single wide draping in consecutive bilateral approaches removes the needs of changing patients' position. Whole thoracoscopic procedure for wedge resection of bullae lesions was conducted without difficulty. The total operation time took 65 min and the patient discharged 3 days after the operation. The patient was followed for 24 months without recurrence of both sides. Another 18-year-old boy was admitted with bilateral spontaneous pneumothorax and single-staged uniportal VATS was also performed in the supine position. The total operation time took 79 min and the patient discharged on postoperative day 4. He was followed for 19 months without recurrence of both sides. Single-staged uniportal VATS approach yielded satisfactory results from simplicity that not requires position change compared to conventional multi-ports VATS in the lateral position, and with better cosmetics. This technique is thought to be a feasible procedure in selective patients with SBPSP or with contralateral bullae for preventive role.

Readiness Review of BWXT for Fabrication of AGR 5/6/7 Compacts

Energy Technology Data Exchange (ETDEWEB)

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

2017-02-01

In support of preparations for fabricating compacts for the Advanced Gas Reactor (AGR) fuel qualification irradiation experiments (AGR-5/6/7), Idaho National Laboratory (INL) conducted a readiness review of the BWX Technology (BWXT) procedures, processes, and equipment associated with compact fabrication activities at the BWXT Nuclear Operations Group (BWXT-NOG) facility outside Lynchburg, VirginiaVA. The readiness review used quality assurance requirements taken from the American Society of Mechanical Engineers (ASME) Nuclear Quality Assurance Standard (NQA-1-2008/1a-2009) as a basis to assess readiness to start compact fabrication.

Compact femtosecond electron diffractometer with 100 keV electron bunches approaching the single-electron pulse duration limit

International Nuclear Information System (INIS)

Waldecker, Lutz; Bertoni, Roman; Ernstorfer, Ralph

2015-01-01

We present the design and implementation of a highly compact femtosecond electron diffractometer working at electron energies up to 100 keV. We use a multi-body particle tracing code to simulate electron bunch propagation through the setup and to calculate pulse durations at the sample position. Our simulations show that electron bunches containing few thousands of electrons per bunch are only weakly broadened by space-charge effects and their pulse duration is thus close to the one of a single-electron wavepacket. With our compact setup, we can create electron bunches containing up to 5000 electrons with a pulse duration below 100 fs on the sample. We use the diffractometer to track the energy transfer from photoexcited electrons to the lattice in a thin film of titanium. This process takes place on the timescale of few-hundred femtoseconds and a fully equilibrated state is reached within 1 ps

Surgical reconstruction of pressure ulcer defects: a single- or two-stage procedure?

LENUS (Irish Health Repository)

Laing, Tereze A

2012-02-01

BACKGROUND: The surgical management of pressure ulcers traditionally involved staged procedures, with initial debridement of necrotic or infected material followed by reconstruction at a later date when the wound was deemed viable and free of gross infection. However, over the past decade, it has been suggested that a single-stage procedure, combining initial debridement and definitive reconstruction, may provide advantages over staged surgery. We present our experience with the staged approach and review the current evidence for both methods. SUBJECTS AND SETTINGS: : We reviewed medical records of all patients referred to our service for pressure ulcer management between October 2001 and October 2007. The National Rehabilitation Hospital is the national center in Ireland for primary rehabilitation of adults and children suffering from spinal and brain injury, serving patients locally and from around the country. METHODS: All subjects who were managed surgically underwent a 2-stage procedure, with initial debridement and subsequent reconstruction. The main outcome measures were length of hospital stay, postoperative morbidity and mortality, and time to complete ulcer healing. RESULTS: Forty-one of 108 patients with 58 pressure ulcers were managed surgically. All patients underwent initial surgical debridement and 20 patients underwent subsequent pressure ulcer reconstruction. Postreconstructive complications occurred in 5 patients (20%). The mean time to complete ulcer healing was 17.4 weeks. Partial flap necrosis occurred in 3 patients, but there were no episodes of flap failure. CONCLUSIONS: We achieved favorable results with a 2-stage reconstruction technique and suggest that the paucity of evidence related to single-stage procedures does not support a change in surgical management.

Analysis of the performance of fuel cells PWR with a single enrichment and radial distribution of enrichments

International Nuclear Information System (INIS)

Vargas, S.; Gonzalez, J. A.; Alonso, G.; Del Valle, E.; Xolocostli M, J. V.

2008-01-01

One of the main challenges in the design of fuel assemblies is the efficient use of uranium achieving burnt homogeneous of the fuel rods as well as the burnt maximum possible of the same ones to the unload. In the case of the assemblies type PWR has been decided actually for fuel assemblies with a single radial enrichment. The present work has like effect to show the because of this decision, reason why a comparison of the neutronic performance of two fuel cells takes place with the same enrichment average but one of them with radial distribution of enrichment and the other with a single enrichment equal to the average. The results shown in the present study of the behavior of the neutron flow as well as the power distribution through of assembly sustain the because of a single radial enrichment. (Author)

Limits to the use of highly compacted bentonite as a deterrent for microbiologically influenced corrosion in a nuclear fuel waste repository

Science.gov (United States)

Stroes-Gascoyne, Simcha; Hamon, Connie J.; Maak, Peter

Recent studies have suggested that microbial activity in highly compacted bentonite (⩾1600 kg/m 3) is severely suppressed. Therefore, it appears that the dry density of emplaced bentonite barriers in a geological repository for nuclear waste may be tailored such that a microbiologically unfavorable environment can be created adjacent to used fuel containers. This would ensure that microbiologically influenced corrosion is a negligible contributor to the overall corrosion process. However, this premise is valid only as long as the emplaced bentonite maintains a uniform high dry density (⩾1600 kg/m 3) because it has been shown that high dry density only suppresses microbial activity but not necessarily eliminates the viable microbial population in bentonite. In a repository, a reduction in the dry density of highly compacted bentonite may occur at a number of interface locations, such as placement gaps, contact regions with materials of different densities and contact points with water-carrying fractures in the rock. Experiments were carried out in our laboratory to examine the effects of a reduction in dry density (from 1600 kg/m 3 to about 1000 kg/m 3) on the recovery of microbial culturability in compacted bentonite. Results showed that upon expansion of compacted bentonite into a void, the resulting reduction in dry density stimulated or restored culturability of indigenous microbes. In a repository this would increase the possibility of in situ activity, which might be detrimental for the longevity of waste containers. Reductions in dry density, therefore, should be minimized or eliminated by adequate design and placement methods of compacted bentonite. Materials compliance models can be used to determine the required as-placed dry densities of bentonite buffer and gap fillings to achieve specific targets for long-term equilibrium dry densities for various container placement room designs. Locations where flowing fractures could be in contact with highly

Compact scanning transmission x-ray microscope at the photon factory

International Nuclear Information System (INIS)

Takeichi, Yasuo; Inami, Nobuhito; Ono, Kanta; Suga, Hiroki; Takahashi, Yoshio

2016-01-01

We report the design and performance of a compact scanning transmission X-ray microscope developed at the Photon Factory. Piezo-driven linear stages are used as coarse stages of the microscope to realize excellent compactness, mobility, and vibrational and thermal stability. An X-ray beam with an intensity of ∼10 7 photons/s was focused to a diameter of ∼40 nm at the sample. At the soft X-ray undulator beamline used with the microscope, a wide range of photon energies (250–1600 eV) is available. The microscope has been used to research energy materials and in environmental sciences

FY 1998 annual report on the development of fuel cell power generation techniques. Research and development of solid electrolyte fuel cells (research results); 1998 nendo nenryo denchi gijutsu kaihatsu. Kotai denkaishitsugata nenryo denchi no kenkyu kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

Described herein are the FY 1998 research and development results of solid electrolyte fuel cells. For R and D of the tubular type cell by the wet processing technique, the tests are conducted to evaluate the initial performance and long-term durability for continuous operation of the single tubular cell. For development of the several-kW class modules, computer-aided simulations are conducted. For R and D of material and substrate techniques, the thermal cycle characteristics, cell characteristics and stress of the cell modules are evaluated, in order to evaluate their reliability. The thermal cycle test results indicate that performance of the single-stage cell is unaffected by the thermal cycles. It is found by the stress evaluation that use of the separator plate having a higher thermal expansion coefficient than the electrolyte plate and use of the sealant having a thermal expansion coefficient close to that of the electrolyte plate are effective means to reduce stresses. For the research to reduce costs of the cell materials, their chemical, mechanical and thermal characteristics are evaluated. For the system research, the areas for which the compact systems are suitable and their optimization are studied. (NEDO)

Safety Consideration for a Wet Interim Spent Fuel Store at Conceptual Design Stage

International Nuclear Information System (INIS)

Astoux, Marion

2014-01-01

EDF Energy plans to build and operate two UK EPRs at the Hinkley Point C (HPC) site in Somerset, England. Spent fuel from the UK EPRs will need to be managed from the time it is discharged from the reactor until it is ultimately disposed of and this will involve storing the spent fuel for a period in the fuel building and thereafter in a dedicated interim facility until it can be emplaced within the UK Geological Disposal Facility. EDF Energy has proposed that this interim store should be located on the Hinkley Point site which is consistent with UK policy. This Interim Spent Fuel Store (ISFS) will have the capability to store for at least one hundred years the spent fuel arising from the operation of the two EPR units (sixty years operation). Therefore, specificities regarding the lifetime of the facility have to be accounted for its design. The choice of interim storage technology was considered in some depth for the HPC project and wet storage (pool) was selected. The facility is currently at conceptual design stage, although its construction will be part of main site construction phase. Safety functions and safety requirements for this storage facility have been defined, in compliance with WENRA 'Waste and Spent Fuel Storage - Safety Reference Level Report' and IAEA Specific Safety Guide no. 15 'Storage of Spent Nuclear Fuel'. EDF technical know-how, operational feedback on existing storage pools, UK regulatory context and Fukushima experience feedback have also been accounted for. Achievement of the safety functions as passively as reasonably practicable is a key issue for the design, especially in accident situations. Regarding lifetime aspects, ageing management of equipments, optimisation of the refurbishment, climate change, passivity of the facility, and long-term achievement of the safety functions are among the subjects to consider. Adequate Operational Limits and Conditions will also have to be defined, to enable the long-term achievement of the safety

Design and performance of a compact scanning transmission X-ray microscope at the Photon Factory

Energy Technology Data Exchange (ETDEWEB)

Takeichi, Y., E-mail: yasuo.takeichi@kek.jp; Mase, K.; Ono, K. [Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba 305-0801 (Japan); Department of Materials Structure Science, SOKENDAI (The Graduate University for Advanced Studies), 1-1 Oho, Tsukuba 305-0801 (Japan); Inami, N. [Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba 305-0801 (Japan); Suga, H. [Department of Earth and Planetary Systems Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526 (Japan); Miyamoto, C. [Department of Earth and Planetary Systems Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku 113-0033 (Japan); Ueno, T. [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Takahashi, Y. [Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba 305-0801 (Japan); Department of Earth and Planetary Systems Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526 (Japan); Department of Earth and Planetary Systems Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku 113-0033 (Japan)

2016-01-15

We present a new compact instrument designed for scanning transmission X-ray microscopy. It has piezo-driven linear stages, making it small and light. Optical components from the virtual source point to the detector are located on a single optical table, resulting in a portable instrument that can be operated at a general-purpose spectroscopy beamline without requiring any major reconstruction. Careful consideration has been given to solving the vibration problem common to high-resolution microscopy, so as not to affect the spatial resolution determined by the Fresnel zone plate. Results on bacteriogenic iron oxides, single particle aerosols, and rare-earth permanent magnets are presented as examples of its performance under diverse applications.

Low-enriched uranium-molybdenum fuel plate development

International Nuclear Information System (INIS)

Wiencek, T.C.; Prokofiev, I.G.

2000-01-01

To examine the fabricability of low-enriched uranium-molybdenum powders, full-size 450 x 60 x 0.5-mm (17.7 x 2.4 x 0.020-in.) fuel zone test plates loaded to 6 g U/cm 3 were produced. U-10 wt.% Mo powders produced by two methods, centrifugal atomization and grinding, were tested. These powders were supplied at no cost to Argonne National Laboratory by the Korean Atomic Energy Research Institute and Atomic Energy of Canada Limited, respectively. Fuel homogeneity indicated that both of the powders produced acceptable fuel plates. Operator skill during loading of the powder into the compacting die and fuel powder morphology were found to be important when striving to achieve homogeneous fuel distribution. Smaller, 94 x 22 x 0.6-mm (3.7 x 0.87 x 0.025-in.) fuel zone, test plates were fabricated using U-10 wt.% Mo foil disks instead of a conventional powder metallurgy compact. Two fuel plates of this type are currently undergoing irradiation in the RERTR-4 high-density fuel experiment in the Advanced Test Reactor. (author)

Irradiation Testing of TRISO-Coated Particle Fuel in Korea

International Nuclear Information System (INIS)

Kim, Bong Goo; Yeo, Sunghwan; Jeong, Kyung-Chai; Eom, Sung-Ho; Kim, Yeon-Ku; Kim, Woong Ki; Lee, Young Woo; Cho, Moon Sung; Kim, Yong Wan

2014-01-01

In Korea, coated particle fuel is being developed to support development of a VHTR. At the end of March 2014, the first irradiation test in HANARO at KAERI to demonstrate and qualify TRISO-coated particle fuel for use in a VHTR was terminated. This experiment was conducted in an inert gas atmosphere without on-line temperature monitoring and control, or on-line fission product monitoring of the sweep gas. The irradiation device contained two test rods, one has nine fuel compacts and the other five compacts and eight graphite specimens. Each compact contains about 260 TRISO-coated particles. The duration of irradiation testing at HANARO was about 135 full power days from last August 2013. The maximum average power per particle was about 165 mW/particle. The calculated peak burnup of the TRISO-coated fuel was a little less than 4 atom percent. Post-irradiation examination is being carried out at KAERI’s Irradiated Material Examination Facility beginning in September of 2014. This paper describes characteristics of coated particle fuel, the design of the test rod and irradiation device for this coated particle fuel, and discusses the technical results of irradiation testing at HANARO. (author)

Improving the AGR fuel testing power density profile versus irradiation-time in the advanced test reactor

International Nuclear Information System (INIS)

Chang, Gray S.; Lillo, Misti A.; Maki, John T.; Petti, David A.

2009-01-01

The Very High Temperature gas-cooled Reactor (VHTR), which is currently being developed, achieves simplification of safety through reliance on ceramic-coated fuel particles. Each TRISO-coated fuel particle has its own containment which serves as the principal barrier against radionuclide release under normal operating and accident conditions. These fuel particles, in the form of graphite fuel compacts, are currently undergoing a series of irradiation tests in the Advanced Test Reactor (ATR) at the Idaho National Laboratory (INL) to support the Advanced Gas-Cooled Reactor (AGR) fuel qualification program. A representive coated fuel particle with an 235 U enrichment of 19.8 wt% was used in this analysis. The fuel burnup analysis tool used to perform the neutronics study reported herein, couples the Monte Carlo transport code MCNP, with the radioactive decay and burnup code ORIGEN2. The fuel burnup methodology known as Monte-Carlo with ORIGEN2 (MCWO) was used to evaluate the AGR experiment assembly and demonstrate compliance with ATR safety requirements. For the AGR graphite fuel compacts, the MCWO-calculated fission power density (FPD) due to neutron fission in 235 U is an important design parameter. One of the more important AGR fuel testing requirements is to maintain the peak fuel compact temperature close to 1250degC throughout the proposed irradiation campaign of 550 effective full power days (EFPDs). Based on the MCWO-calculated FPD, a fixed gas gap size was designed to allow regulation of the fuel compact temperatures throughout the entire fuel irradiation campaign by filling the gap with a mixture of helium and neon gases. The chosen fixed gas gap can only regulate the peak fuel compact temperature in the desired range during the irradiation test if the ratio of the peak power density to the time-dependent low power density (P/T) at 550 EFPDs is less than 2.5. However, given the near constant neutron flux within the ATR driver core and the depletion of 235 U

First application experiments with the Stockholm compact soft x-ray microscope

International Nuclear Information System (INIS)

Bertilson, M; Hofsten, O von; Lindblom, M; Holmberg, A; Takman, P; Vogt, U; Hertz, H; Thieme, J

2009-01-01

Most soft x-ray microscopes operating in the water window (λ = 2.3 - 4.4 nm) rely on synchrotron radiation sources. In the future we believe scientists will use soft x-ray microscopes as one imaging tool among others in their own laboratory. For this purpose we have developed a full field soft x-ray microscope with a laser-plasma source compact enough to fit on an optical table. In this contribution we describe the current status of this microscope now featuring stable operation at λ = 3.37 nm or λ 2.48 nm. In-house fabricated single element zone plates offering the possibility to perform phase contrast imaging have been implemented. We also report on the first application experiments for compact soft x-ray microscopy, including results from studies of clay minerals and colloids existing in nature and results from phase optics experiments. Planned upgrades of the microscope include increasing the source brightness, implementing more efficient condenser optics, and installing a cryo sample stage for tomography. These improvements will open up for further applications, especially in the field of biological imaging.

Nuclear reactor fuel elements

International Nuclear Information System (INIS)

Butterfield, C.E.; Waite, E.

1982-01-01

A nuclear reactor fuel element comprising a column of vibration compacted fuel which is retained in consolidated condition by a thimble shaped plug. The plug is wedged into gripping engagement with the wall of the sheath by a wedge. The wedge material has a lower coefficient of expansion than the sheath material so that at reactor operating temperature the retainer can relax sufficient to accommodate thermal expansion of the column of fuel. (author)

Compacted graphite iron: Cast iron makes a comeback

Science.gov (United States)

Dawson, S.

1994-08-01

Although compacted graphite iron has been known for more than four decades, the absence of a reliable mass-production technique has resulted in relatively little effort to exploit its operational benefits. However, a proven on-line process control technology developed by SinterCast allows for series production of complex components in high-quality CGI. The improved mechanical properties of compacted graphite iron relative to conventional gray iron allow for substantial weight reduction in gasoline and diesel engines or substantial increases in horsepower, or an optimal combination of both. Concurrent with these primary benefits, CGI also provides significant emissions and fuel efficiency benefits allowing automakers to meet legislated performance standards. The operational and environmental benefits of compacted graphite iron together with its low cost and recyclability reinforce cast iron as a prime engineering material for the future.

Green strength of zirconium sponge and uranium dioxide powder compacts

International Nuclear Information System (INIS)

Balakrishna, Palanki; Murty, B. Narasimha; Sahoo, P.K.; Gopalakrishna, T.

2008-01-01

Zirconium metal sponge is compacted into rectangular or cylindrical shapes using hydraulic presses. These shapes are stacked and electron beam welded to form a long electrode suitable for vacuum arc melting and casting into solid ingots. The compact electrodes should be sufficiently strong to prevent breakage in handling as well as during vacuum arc melting. Usually, the welds are strong and the electrode strength is limited by the green strength of the compacts, which constitute the electrode. Green strength is also required in uranium dioxide (UO 2 ) powder compacts, to withstand stresses during de-tensioning after compaction as well as during ejection from the die and for subsequent handling by man and machine. The strengths of zirconium sponge and UO 2 powder compacts have been determined by bending and crushing respectively, and Weibul moduli evaluated. The green density of coarse sponge compact was found to be larger than that from finer sponge. The green density of compacts from lightly attrited UO 2 powder was higher than that from unattrited category, accompanied by an improvement in UO 2 green crushing strength. The factors governing green strength have been examined in the light of published literature and experimental evidence. The methodology and results provide a basis for quality control in metal sponge and ceramic powder compaction in the manufacture of nuclear fuel

Study on the Applicability of Electron Beam Welding Methods to Assembly a Fuel Compact and Al Cover Plate of Research Reactor Plate Type Fuel

Energy Technology Data Exchange (ETDEWEB)

Lee, Hae In; Lee, Yoon Sang; Lee, Don Dae; Jeong, Yong Jin; Kwon, Sun Chil; Kim, Soo Sung; Park, Jong Man [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2012-05-15

Among the research reactor plate type fuel fabrication processes, there is an assembly process between fuel meat compact and Al cover plates using a welding method prior to rolling process. The assembly process is such as the Al frame and Al cover plate should be welded properly as shown in Fig. 1. For welding, TIG(Tungsten Inert Gas) welding methods has been used conventionally, but in this study an electron beam welding(EB welding) technique which uses the electron beam of a high velocity for joining two materials is introduced to the assembly. The work pieces are melted as the kinetic energy of the electron beam is transformed into heat to join the two parts of the weld. The welding is often done in the conditions in a vacuum to prevent dispersion of the electron beam. The electron beam welding process has many ad-vantages such as contamination of the welds could be prevented, the penetration of the weld is deep, and also the strain of the welding area is less than other methods. In this study, to find optimal condition of the EB welding process, a welding speed, a beam current and an acceleration voltage were changed. To analyzing the welding results, the shape of the beads and defects of welding area was used. The width and depth of the beads were measured as well

Study on the Applicability of Electron Beam Welding Methods to Assembly a Fuel Compact and Al Cover Plate of Research Reactor Plate Type Fuel

International Nuclear Information System (INIS)

Lee, Hae In; Lee, Yoon Sang; Lee, Don Dae; Jeong, Yong Jin; Kwon, Sun Chil; Kim, Soo Sung; Park, Jong Man

2012-01-01

Among the research reactor plate type fuel fabrication processes, there is an assembly process between fuel meat compact and Al cover plates using a welding method prior to rolling process. The assembly process is such as the Al frame and Al cover plate should be welded properly as shown in Fig. 1. For welding, TIG(Tungsten Inert Gas) welding methods has been used conventionally, but in this study an electron beam welding(EB welding) technique which uses the electron beam of a high velocity for joining two materials is introduced to the assembly. The work pieces are melted as the kinetic energy of the electron beam is transformed into heat to join the two parts of the weld. The welding is often done in the conditions in a vacuum to prevent dispersion of the electron beam. The electron beam welding process has many ad-vantages such as contamination of the welds could be prevented, the penetration of the weld is deep, and also the strain of the welding area is less than other methods. In this study, to find optimal condition of the EB welding process, a welding speed, a beam current and an acceleration voltage were changed. To analyzing the welding results, the shape of the beads and defects of welding area was used. The width and depth of the beads were measured as well

Advanced coal-fueled gas turbine systems

Energy Technology Data Exchange (ETDEWEB)

Wenglarz, R.A.

1994-08-01

Several technology advances since the early coal-fueled turbine programs that address technical issues of coal as a turbine fuel have been developed in the early 1980s: Coal-water suspensions as fuel form, improved methods for removing ash and contaminants from coal, staged combustion for reducing NO{sub x} emissions from fuel-bound nitrogen, and greater understanding of deposition/erosion/corrosion and their control. Several Advanced Coal-Fueled Gas Turbine Systems programs were awarded to gas turbine manufacturers for for components development and proof of concept tests; one of these was Allison. Tests were conducted in a subscale coal combustion facility and a full-scale facility operating a coal combustor sized to the Allison Model 501-K industrial turbine. A rich-quench-lean (RQL), low nitrogen oxide combustor design incorporating hot gas cleanup was developed for coal fuels; this should also be applicable to biomass, etc. The combustor tests showed NO{sub x} and CO emissions {le} levels for turbines operating with natural gas. Water washing of vanes from the turbine removed the deposits. Systems and economic evaluations identified two possible applications for RQL turbines: Cogeneration plants based on Allison 501-K turbine (output 3.7 MW(e), 23,000 lbs/hr steam) and combined cycle power plants based on 50 MW or larger gas turbines. Coal-fueled cogeneration plant configurations were defined and evaluated for site specific factors. A coal-fueled turbine combined cycle plant design was identified which is simple, compact, and results in lower capital cost, with comparable efficiency and low emissions relative to other coal technologies (gasification, advanced PFBC).

COBRA-SFS predictions of single assembly spent fuel heat transfer data

International Nuclear Information System (INIS)

Lombardo, N.J.; Michener, T.E.; Wheeler, C.L.; Rector, D.R.

1986-04-01

The study reported here is one of several efforts to evaluate and qualify the COBRA-SFS computer code for use in spent fuel storage system thermal analysis. The ability of COBRA-SFS to predict the thermal response of two single assembly spent fuel heat transfer tests was investigated through comparisons of predictions with experimental test data. From these comparisons, conclusions regarding the computational treatment of the physical phenomena occurring within a storage system can be made. This objective was successfully accomplished as reasonable agreement between predictions and data were obtained for the 21 individual test cases of the two experiments

Indigenous development of system integration for proton exchange membrane fuel cell operation

International Nuclear Information System (INIS)

Hussain, S.; Arshad, M.; Anjum, A.R.

2011-01-01

System integration was developed for fuel cell to control various parameters including voltage, current, power, temperature, pressure of gas (H/sub 2/), humidification, etc. The compact software has also been developed for monitoring different parameters of fuel cell system. System integrated was installed on fuel cell stack to manipulate these parameters. The compact software has been linked with the integrated system for visual monitoring of different parameters of fuel cell system during operation on PC. The installation of software and integrated system on fuel cell stack is the key achievement for the safe operation of fuel cell stack and for the provision of requisite power to any electric device for optimum performance. The compact software was developed for micro controller in KIEL. Control card and driver card are controlled by software-driven micro controller. A communication protocol was designed and developed. PC software has been developed to control and watch the values of all parameters of fuel cell such as voltage, current, power, temperature, pressure of hydrogen, pressure of oxygen, operational times and performance of the system on computer screen. (author)

Single-stage osseointegrated implants for nasal prosthodontic rehabilitation: A clinical report.

Science.gov (United States)

de Carvalho, Bruna M D F; Freitas-Pontes, Karina M; de Negreiros, Wagner A; Verde, Marcus A R L

2015-08-01

Malignant tumors in the nasal region may be treated by means of invasive surgical procedures, with large facial losses. Nasal prostheses, retained by osseointegrated facial implants, instead of plastic surgery, will, in most patients, offer good biomechanical and cosmetic results. This clinical report describes the prosthetic rehabilitation of a patient with nasal cancer who had the entire nasal vestibule removed in a single-stage surgical procedure in order to shorten the rehabilitation time. The nasal prosthesis was built on a 3-magnet bar and was made of platinum silicone with intrinsic pigmentation, thereby restoring the patient's appearance and self-esteem. The authors concluded that single-stage implants may reduce the rehabilitation time to as little as 1 month, and the correct use of materials and techniques may significantly improve the nasal prosthesis. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Modeling compaction-induced energy dissipation of granular HMX

Energy Technology Data Exchange (ETDEWEB)

Gonthier, K.A. [Lamar Univ., Beaumont, TX (US). Dept. of Mechanical Engineering; Menikoff, R.; Son, S.F.; Asay, B.W. [Los Alamos National Lab., NM (US)

1998-12-31

A thermodynamically consistent model is developed for the compaction of granular solids. The model is an extension of the single phase limit of two-phase continuum models used to describe Deflagration-to-Detonation Transition (DDT) experiments. The focus is on the energetics and dissipation of the compaction process. Changes in volume fraction are partitioned into reversible and irreversible components. Unlike conventional DDT models, the model is applicable from the quasi-static to dynamic compaction regimes for elastic, plastic, or brittle materials. When applied to the compaction of granular HMX (a brittle material), the model predicts results commensurate with experiments including stress relaxation, hysteresis, and energy dissipation. The model provides a suitable starting point for the development of thermal energy localization sub-scale models based on compaction-induced dissipation.

Recording single neurons' action potentials from freely moving pigeons across three stages of learning.

Science.gov (United States)

Starosta, Sarah; Stüttgen, Maik C; Güntürkün, Onur

2014-06-02

While the subject of learning has attracted immense interest from both behavioral and neural scientists, only relatively few investigators have observed single-neuron activity while animals are acquiring an operantly conditioned response, or when that response is extinguished. But even in these cases, observation periods usually encompass only a single stage of learning, i.e. acquisition or extinction, but not both (exceptions include protocols employing reversal learning; see Bingman et al.(1) for an example). However, acquisition and extinction entail different learning mechanisms and are therefore expected to be accompanied by different types and/or loci of neural plasticity. Accordingly, we developed a behavioral paradigm which institutes three stages of learning in a single behavioral session and which is well suited for the simultaneous recording of single neurons' action potentials. Animals are trained on a single-interval forced choice task which requires mapping each of two possible choice responses to the presentation of different novel visual stimuli (acquisition). After having reached a predefined performance criterion, one of the two choice responses is no longer reinforced (extinction). Following a certain decrement in performance level, correct responses are reinforced again (reacquisition). By using a new set of stimuli in every session, animals can undergo the acquisition-extinction-reacquisition process repeatedly. Because all three stages of learning occur in a single behavioral session, the paradigm is ideal for the simultaneous observation of the spiking output of multiple single neurons. We use pigeons as model systems, but the task can easily be adapted to any other species capable of conditioned discrimination learning.

In Situ Multi-Species (O2, N2, Fuel, Other) Fiber Optic Sensor for Fuel Tank Ullage

Science.gov (United States)

Nguyen, Quang-Viet

2007-01-01

A rugged and compact fiber optic sensor system for in situ real-time measurement of nitrogen (N2), oxygen (O2), hydrocarbon (HC) fuel vapors, and other gases has been developed over the past several years at Glenn Research Center. The intrinsically-safe, solid-state fiber optic sensor system provides a 1% precision measurement (by volume) of multiple gases in a 5-sec time window. The sensor has no consumable parts to wear out and requires less than 25 W of electrical power to operate. The sensor head is rugged and compact and is ideal for use in harsh environments such as inside an aircraft fuel tank, or as a feedback sensor in the vent-box of an on-board inert gas generation system (OBIGGS). Multiple sensor heads can be monitored with a single optical detection unit for a cost-effective multi-point sensor system. The present sensor technology is unique in its ability to measure N2 concentration directly, and in its ability to differentiate different types of HC fuels. The present sensor system provides value-added aircraft safety information by simultaneously and directly measuring the nitrogen-oxygen-fuel triplet, which provides the following advantages: (1) information regarding the extent of inerting by N2, (2) information regarding the chemical equivalence ratio, (3) information regarding the composition of the aircraft fuel, and (4) by providing a self-consistent calibration by utilizing a singular sensor for all species. Using the extra information made available by this sensor permits the ignitability of a fuel-oxidizer mixture to be more accurately characterized, which may permit a reduction in the amount of inerting required on a real-time basis, and yet still maintain a fire-safe fuel tank. This translates to an increase in fuel tank fire-safety through a better understanding of the physics of fuel ignition, and at the same time, a reduction in compressed bleed air usage and concomitant aircraft operational costs over the long-run. The present fiber

Non-destructive system to evaluate critical properties of asphalt compaction : [research brief].

Science.gov (United States)

2013-12-01

The Wisconsin Highway Research Program sponsored a two-stage investigation to develop a non-destructive system to evaluate critical compaction properties and characteristics of asphalt pavements during the densification process. Stage One activities ...

Two-stage single-volume exchange transfusion in severe hemolytic disease of the newborn.

Science.gov (United States)

Abbas, Wael; Attia, Nayera I; Hassanein, Sahar M A

2012-07-01

Evaluation of two-stage single-volume exchange transfusion (TSSV-ET) in decreasing the post-exchange rebound increase in serum bilirubin level, with subsequent reduction of the need for repeated exchange transfusions. The study included 104 neonates with hyperbilirubinemia needing exchange transfusion. They were randomly enrolled into two equal groups, each group comprised 52 neonates. TSSV-ET was performed for the 52 neonates and the traditional single-stage double-volume exchange transfusion (SSDV-ET) was performed to 52 neonates. TSSV-ET significantly lowered rebound serum bilirubin level (12.7 ± 1.1 mg/dL), compared to SSDV-ET (17.3 ± 1.7 mg/dL), p < 0.001. Need for repeated exchange transfusions was significantly lower in TSSV-ET group (13.5%), compared to 32.7% in SSDV-ET group, p < 0.05. No significant difference was found between the two groups as regards the morbidity (11.5% and 9.6%, respectively) and the mortality (1.9% for both groups). Two-stage single-volume exchange transfusion proved to be more effective in reducing rebound serum bilirubin level post-exchange and in decreasing the need for repeated exchange transfusions.

Calculation of the external dose rate in the spent fuel pool for the case to use compact racks

International Nuclear Information System (INIS)

Passos, E.M. dos; Alves, A.S.M.

1988-01-01

The possible introduction of compact racks in the spent fuel pool of the Angra 1 Nuclear Power Plant largely inreases its storage capacity, but originates an increase of the gamma radiation sources. The precise evaluation of the effects of the adoption of this option on the external gamma dose rates and also on the thickness of the concrete shielding requires the utilization of sofisticated computer codes (QAD, ANISN), which allow the calculation of the gamma dose rates through thick shielding walls. This paper describes the utilized methodology for the calculation of the modified pool shieldings, showing the obtained results for the Angra 1 NPP case. The gamma dose rate was calculated with the point Kernel model, first analytically, and later through utilization of the tridimensional multigroup QAD computer code. (author) [pt

Development of the fabrication technology of the simulated DUPIC fuel

International Nuclear Information System (INIS)

Kang, Kweon Ho; Yang, M. S.; Bae, K. K. and others

2000-06-01

It is important to get basic data to analysis physical properties, behavior in reactor and performance of the DUPIC fuel because physical properties of the DUPIC fuel is different from the commercial UO 2 fuel. But what directly measures physical properties et al. of DUPIC fuel being resinterred simulated spent fuel through OREOX process is very difficult in laboratory owing to its high level radiation. Then fabrication of simulated DUPIC fuel is needed to measure its properties. In this study, processes on powder treatment, OREOX, compaction and sintering to fabricate simulated DUPIC fuel using simulated spent fuel are discribed. To fabricate simulated DUPIC fuel, the powder from 3 times OREOX and 5 times attrition milling simulated spent fuel is compacted with 1.3 ton/cm 2 . Pellets are sintered in 100% H 2 atmosphere over 10 h at 1800 deg C. Sintered densities of pellets are 10.2-10.5 g/cm 3

Compact, single-tube scanning tunneling microscope with thermoelectric cooling.

Science.gov (United States)

Jobbins, Matthew M; Agostino, Christopher J; Michel, Jolai D; Gans, Ashley R; Kandel, S Alex

2013-10-01

We have designed and built a scanning tunneling microscope with a compact inertial-approach mechanism that fits inside the piezoelectric scanner tube. Rigid construction allows the microscope to be operated without the use of external vibration isolators or acoustic enclosures. Thermoelectric cooling and a water-ice bath are used to increase temperature stability when scanning under ambient conditions.

Analysis of fuel pin mechanics in case of flow blockage of a single RBMK channel

International Nuclear Information System (INIS)

Pierro, F.; Moretti, F.; Mazzini, D.; D'Auria, F.

2005-01-01

The evaluation of the consequences of the pressure tube rupture due to accidental overheating is one of the key elements for addressing an RBMK safety analysis, since it causes the lost of design boundaries against the fission products release. Several events are expected to take place: thermal hydraulic crisis (energy unbalance), fuel overheating, fuel rod damage, pressure tube overheating, pressure tube failure and graphite stack damage, Hydrogen and fission products release. The present work deals with the research activity carried out at ''Dipartimento di Ingegneria Meccanica, Nucleare e della Produzione'' (DIMNP) of the University of Pisa aimed at assessing numerical models for safety analysis of the RBMK-1000. The attention is focused on the modelling of (1) a single fuel channel and its surrounding graphite column for evaluating the transient conditions enabling the different damaging phenomena, (2) a single fuel rod for investigating fuel pin behaviour, (3) the ruptured fuel channel for figuring the magnitude of the hydrodynamic loads acting on fuel rods. Different codes were employed to cover the competences for the investigation of each field; in particular, RELAP5 code for thermal-hydraulics, FRAPCON-3 and FRAPTRAN1-2 codes for fuel pin mechanics, FLUENT-6 for fluid dynamics. The paper discusses the numerical models, the analysis capabilities of numerical models in comparison with available data about the Leningrad NPP 1992 accident. Furthermore, the possibility to draw a failure map identifying the range of the cladding safety respect to the transient condition is outlined. (author)

Single-stage micro-scale solvent extraction in parallel microbore tubes using MDIMJ

International Nuclear Information System (INIS)

Darekar, Mayur; Singh, K.K.; Joshi, J.M.; Mukhopadhyay, S.; Shenoy, K.T.

2016-01-01

Single-stage micro-scale solvent extraction of U(VI) from simulated lean streams is explored using micro-scale contactor comprising of a MDIMJ (Monoblock Distributor with Integrated Microfluidic Junction) and PTFE microbore tubes. 30% (v/v) TBP in dodecane has been used as the extracting phase. The objective of the study is to demonstrate numbering up approach for scale-up of micro-scale extraction using indigenously conceptualized and fabricated MDIMJ. First the performance of MIDIMJ for equal flow distribution is tested. Then the effects of inlet flow rate and O/A ratio on stage efficiency and percentage extraction are studied. The experiments show that it is easy to scale-up single-stage micro-scale solvent extraction by using MDIMJ for numbering up approach. Maximum capacity tested is 4.8 LPH. With O/A = 2/1, more than 90% extraction is achieved in a very short contact time of less than 3s. The study thus demonstrates possibility of process intensification and easy scale-up of micro-scale solvent extraction

Performance of single cylinder, direct injection Diesel engine using water fuel emulsions

International Nuclear Information System (INIS)

Abu-Zaid, M.

2004-01-01

A single cylinder Diesel engine study of water-in-Diesel emulsions was conducted to investigate the effect of water emulsification on the engine performance and gases exhaust temperature. Emulsified Diesel fuels of 0, 5, 10, 15 and 20 water/Diesel ratios by volume, were used in a single cylinder, direct injection Diesel engine, operating at 1200-3300 rpm. The results indicate that the addition of water in the form of emulsion improves combustion efficiency. The engine torque, power and brake thermal efficiency increase as the water percentage in the emulsion increases. The average increase in the brake thermal efficiency for 20% water emulsion is approximately 3.5% over the use of Diesel for the engine speed range studied. The proper brake specific fuel consumption and gases exhaust temperature decrease as the percentage of water in the emulsion increases

Panorama 2015 - The global market for compact cars

International Nuclear Information System (INIS)

Vinot, Simon; Ivanic, Tanja

2014-12-01

The search for fuel-saving solutions has led to a trend for acquiring smaller and lighter cars. Small compact cars, whether powered by internal combustion or electric engines, have gained and are continuing to gain market share, in both mature automobile markets such as Europe or Japan and emerging markets such as India. (authors)

A compact reactor/ORC power source

International Nuclear Information System (INIS)

Meier, K.L.; Kirchner, W.L.; Willcutt, G.J.

1986-01-01

A compact power source that combines an organic Rankine cycle (ORC) electric generator with a nuclear reactor heat source is being designed and fabricated. Incorporating existing ORC technology with proven reactor technology, the compact reactor/ORC power source offers high reliability while minimizing the need for componenet development. Thermal power at 125 kWt is removed from the coated particle fueled, graphite moderated reactor by heat pipes operating at 500 0 C. Outside the reactor vessel and connected to the heat pipes are vaporizers in which the toluene ORC working fluid is heated to 370 0 C. In the turbine-alternator-pump (TAP) combined-rotating unit, the thermal energy of the toluene is converted to 25 kWe of electric power. Lumped parameter systems analyses combined with a finite element thermal analyses combined with a finite element thermal analysis have aided in the power source design. The analysis have provided assurance of reliable multiyear normal operation as well as full power operation with upset conditions, such as failed heat pipes and inoperative ORC vaporizers. Because of inherent high reliability, long life, and insensitivity to upset conditions, this power source is especially suited for use in remote, inaccessible locations where fuel delivery and maintenance costs are high

Effect of Granule Size on Diametric Tolerance of Annular Fuel Pellet

International Nuclear Information System (INIS)

Rhee, Young Woo; Kim, Dong Joo; Kim, Jong Hun; Yang, Jae Ho; Kim, Keon Sik; Kang, Ki Won; Song, Kun Woo

2008-01-01

A dual cooled annular fuel has been seriously considered as a favorable option for an extended power uprate of a Pressurized Water Reactor fuel assembly. An annular fuel shows a lot of advantages from the point of a fuel safety and its economy due to its unique configurational merit such as an increased heat transfer area and a thin pellet thickness. From the viewpoint of the fuel pellet fabrication, however, the unique shape of annular fuel pellet causes challenging difficulties to satisfy a diametric tolerance. A sintered cylindrical PWR fuel pellet fabricated by a conventional double-acting press has an hour-glass shape due to an inhomogeneous green density distribution in a powder compact. Thus, a sintered pellet usually undergoes a centerless grinding process in order to secure diametric tolerance specifications. In the case of an annular pellet fabrication using a conventional double-acting press, the same hour-glass shape would probably occur. An inhomogeneous green density distribution in a powder compact is attributed to granule-granule frictions and granule to pressing mold wall frictions. Frictions result in an irregular pressing load distribution in a powder compact. In order to mitigate the frictions, a lot of process variables should be considered such as pre-compaction pressure, lubricant content, granule size and compaction pressure. The purpose of this study is to investigate the effect of a granule size on the amount of deformation after sintering, in other words, the amount of an hour-glassing. The granules with classified size ranges were made to green annular pellets with the same height and diameters. The hour-glassing amounts of the sintered annular pellets were measured and compared with that of the annular pellet made by unclassified granule

Chilean fuel elements fabrication progress report

International Nuclear Information System (INIS)

Baeza, J.; Contreras, H.; Chavez, J.; Klein, J.; Mansilla, R.; Marin, J.; Medina, R.

1993-01-01

Due to HEU-LEU core conversion necessity for the Chilean MTR reactors, the Fuel Elements Plant is being implemented to LEU nuclear fuel elements fabrication. A glove box line for powder-compact processing designed at CCHEN, which supposed to operate under an automatic control system, is at present under initial tests. Results of first natural uranium fuel plates manufacturing runs are shown

Neutronic design of the RSG-GAS compact core without CIP

International Nuclear Information System (INIS)

Susilo, Jati; Kuntoro, Iman

2002-01-01

Improvement of the efficiency of reactor operation can be chivvied by some ways, such as, the uranium density of the fuel, loading pattern and configuration of core elements. The paper deals with determination of optimal configuration of the compact core with out CIP. Calculations were carried out by means of SRAC-PIJ module for cross section generation and SRAC-ASMBURN for core calculations. The optimal compact core obtained, showed that no-CIP compact core increase highest reactivity value about 0,84 % Δk/k and longest time operation about 1,19 time in the safety criteria that is power peaking factor less then 1,4 and margin control element worth less then volume in the first design that -2,2% Δk/k

Neutronic design of the RSG-GAS compact core without CIP

International Nuclear Information System (INIS)

Jati-Susilo; Iman-Kuntoro

2003-01-01

Improvement of the efficiency of reactor operation can be achieved by some ways, such as, the uranium density of the fuel, loading pattern and configuration of core elements. The paper deals with determination of optimal configuration of the compact core with out CIP. Calculations were carried out by means of SRAC-PIJ module for cross section generation and SRAC-ASMBURN for core calculations. The optimal compact core obtained, showed that no-CIP compact core increase highest reactivity value about 1.06 % Δk/k and longest time operation about 1.19 time in the safety criteria that is power peaking factor less then 1.4 and margin control element worth less then value in the first design that -2.2% Δk/k

UN TRISO Compaction in SiC for FCM Fuel Irradiations

Energy Technology Data Exchange (ETDEWEB)

Terrani, Kurt A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Trammell, Michael P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kiggans, James O. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jolly, Brian C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Skitt, Darren J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2016-11-01

The U.S. Department of Energy Office of Nuclear Energy (DOE-NE) Advanced Fuels Campaign (AFC) is conducting research and development to elevate the technology readiness level of Fully Ceramic Microencapsulated (FCM) fuels, a candidate nuclear fuel with potentially enhanced accident tolerance due to very high fission product retention. One of the early activities in FY17 was to demonstrate production of FCM pellets with uranium nitride TRISO particles. This was carried out in preparation of the larger pellet production campaign in support of the upcoming irradiation testing of this fuel form at INL’s Advanced Test Reactor.

A Multidisciplinary Performance Analysis of a Lifting-Body Single-Stage-to-Orbit Vehicle

Science.gov (United States)

Tartabini, Paul V.; Lepsch, Roger A.; Korte, J. J.; Wurster, Kathryn E.

2000-01-01

Lockheed Martin Skunk Works (LMSW) is currently developing a single-stage-to-orbit reusable launch vehicle called VentureStar(TM) A team at NASA Langley Research Center participated with LMSW in the screening and evaluation of a number of early VentureStar(TM) configurations. The performance analyses that supported these initial studies were conducted to assess the effect of a lifting body shape, linear aerospike engine and metallic thermal protection system (TPS) on the weight and performance of the vehicle. These performance studies were performed in a multidisciplinary fashion that indirectly linked the trajectory optimization with weight estimation and aerothermal analysis tools. This approach was necessary to develop optimized ascent and entry trajectories that met all vehicle design constraints. Significant improvements in ascent performance were achieved when the vehicle flew a lifting trajectory and varied the engine mixture ratio during flight. Also, a considerable reduction in empty weight was possible by adjusting the total oxidizer-to-fuel and liftoff thrust-to-weight ratios. However, the optimal ascent flight profile had to be altered to ensure that the vehicle could be trimmed in pitch using only the flow diverting capability of the aerospike engine. Likewise, the optimal entry trajectory had to be tailored to meet TPS heating rate and transition constraints while satisfying a crossrange requirement.

Study of radial die-wall pressure changes during pharmaceutical powder compaction.

Science.gov (United States)

Abdel-Hamid, Sameh; Betz, Gabriele

2011-04-01

In tablet manufacturing, less attention is paid to the measurement of die-wall pressure than to force-displacement diagrams. Therefore, the aim of this study was to investigate radial stress change during pharmaceutical compaction. The Presster(TM), a tablet-press replicator, was used to characterize compaction behavior of microcrystalline cellulose (viscoelastic), calcium hydrogen phosphate dihydrate (brittle), direct compressible mannitol (plastic), pre-gelatinized starch (plastic/elastic), and spray dried lactose monohydrate (plastic/brittle) by measuring radial die-wall pressure; therefore powders were compacted at different (pre) compaction pressures as well as different speeds. Residual die-wall pressure (RDP) and maximum die-wall pressure (MDP) were measured. Various tablet physical properties were correlated to radial die-wall pressure. With increasing compaction pressure, RDP and MDP (P compaction behavior of materials and detecting friction phenomena in the early stage of development.

Specifying and using pulverised fuel ash as an engineered fill

Energy Technology Data Exchange (ETDEWEB)

Clarke, B.G.; Coombs, R. [University of Newcastle upon Tyne, Newcastle upon Tyne (United Kingdom). Dept. of Civil Engineering

1996-12-31

Claims arising from incorrect use of fill materials are often due to a lack of understanding of material behaviour and incomplete or wrong specifications. This is especially the case when using waste products such as pulverised fuel ash (pfa). A review of current and proposed specifications and current practice highlights some of the problems arising when selecting design parameters and acceptance criteria for pfa. Pfa can be considered a particulate material and properties of a pfa can be ascertained at the design stage because the sources are known. Design parameters are post peak effective strength parameters taken from triaxial or direct shear tests on saturated specimens compacted to 90% of the average maximum dry density. Compaction characteristics and design parameters of a particular source can be determined from tests if it is stockpiled pfa, or historical records if it is conditioned pfa. Method compaction can be used to place pfa but site trials should be carried out to determine the best method. Experience has shown that six to eight passes are sufficient, but usually the movement of construction traffic during tipping and spreading pfa will give the minimum required density. Inundation has little effect on compacted ash provided the water content is within acceptable limits, that is within 20% of the average optimum water content. 6 refs., 6 figs., 3 tabs.

Effect of increased fuel exploitation on the main characteristics of spent WWER 440 fuel

International Nuclear Information System (INIS)

Zib, A.

2001-01-01

The article deals with the effect of a higher fuel exploitation on the main characteristics (particularly radioactivity and decay heat power) of spent WWER 440 fuel. The main characteristics were calculated by using the Origen code. The study was implemented as a three-stage process. In the first stage, the radioactivity and residual thermal power time evolution values were calculated for the 'typical fuel', i. e. fuel assembly with initial enrichment of 3.6% U-235, 3 years in reactor, and burnup of 30 MWd/kg U. In the second stage, ceteris paribus radioactivity and thermal power analyses of sensitivity to changes in the fuel burnup, initial fuel enrichment, and time in reactor were carried out for the typical fuel assembly. In the third stage, the effect of changes in all three variables was investigated for fuel assemblies possessing parameters that approach those applied at the Dukovany NPP. The effect of a higher fuel exploitation on the interim fuel storage is also mentioned. (author)

Evaluation of automatic vacuum- assisted compaction solutions

Directory of Open Access Journals (Sweden)

M. Brzeziński

2011-01-01

Full Text Available Currently on the mould-making machines market the companies like: DiSA, KUENKEL WAGNER, HAFLINGER, HEINRICH WAGNER SINTO, HUNTER, SAVELLI AND TECHNICAL play significant role. These companies are the manufacturers of various solutions in machines and instalations applied in foundry engineering. Automatic foundry machines for compaction of green sand have the major role in mechanisation and automation processes of making the mould. The concept of operation of automatic machines is based on the static and dynamic methods of compacting the green sand. The method which gains the importance is the compacting method by using the energy of the air pressure. It's the initial stage or the supporting process of compacting the green sand. However in the automatic mould making machines using this method it's essential to use the additional compaction of the mass in order to receive the final parameters of the form. In the constructional solutions of the machines there is the additional division which concerns the method of putting the sand into the mould box. This division distinquishes the transport of the sand with simultaneous compaction or the putting of the sand without the pre-compaction. As the solutions of the major manufacturers are often the subject for application in various foundries, the authors of the paper would like/have the confidence to present their own evaluation process confirmed by their own researches and independent analysis of the producers' solutions.

A high-power compact regenerative amplifier FEL

International Nuclear Information System (INIS)

Nguyen, D.C.; Sheffield, R.L.; Fortgang, C.M.; Kinross-Wright, J.M.; Ebrahim, N.A.; Goldstein, J.C.

1997-01-01

The Regenerative Amplifier FEL (RAFEL) is a new FEL approach aimed at achieving the highest optical power from a compact rf-linac FEL. The key idea is to feed back a small fraction ( 5 in single pass) wiggler to enable the FEL to reach saturation in a few passes. This paper summarizes the design of a high-power compact regenerative amplifier FEL and describes the first experimental demonstration of the RAFEL concept

Durability of Self Compacting Concrete

International Nuclear Information System (INIS)

Benmarce, A.; Boudjehem, H.; Bendjhaiche, R.

2011-01-01

Self compacting concrete (SCC) seem to be a very promising materials for construction thanks to their properties in a fresh state. Studying of the influence of the parameters of specific designed mixes to their mechanical, physical and chemical characteristics in a state hardened is an important stage so that it can be useful for new-to-the-field researchers and designers (worldwide) beginning studies and work involving self compacting concrete. The objective of this research is to study the durability of self compacting concrete. The durability of concrete depends very much on the porosity; the latter determines the intensity of interactions with aggressive agents. The pores inside of concrete facilitate the process of damage, which began generally on the surface. We are interested to measure the porosity of concrete on five SCC with different compositions (w/c, additives) and vibrated concrete to highlight the influence of the latter on the porosity, thereafter on the compressive strength and the transfer properties (oxygen permeability, chloride ion diffusion, capillary absorption). (author)

Planck 2013 results. XXVIII. The Planck Catalogue of Compact Sources

DEFF Research Database (Denmark)

Planck Collaboration,; Ade, P. A. R.; Aghanim, N.

2013-01-01

The Planck Catalogue of Compact Sources (PCCS) is the catalogue of sources detected in the Planck nominal mission data. It consists of nine single-frequency catalogues of compact sources containing reliable sources, both Galactic and extragalactic, detected over the entire sky. The PCCS covers th...

Irradiation performance of AGR-1 high temperature reactor fuel

Energy Technology Data Exchange (ETDEWEB)

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

2014-10-01

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

Upgrading of the Munich reactor with a compact core

International Nuclear Information System (INIS)

Boening, K.; Glaeser, W.; Meier, J.; Rau, G.; Roehrmoser, A.; Zhang, L.

1985-01-01

An extremely small reactor core has been proposed for the project of substantial modernization of the FRM research reactor at Munich. According to the present status this 'compact core' will be a cylinder with a diameter of about 20 cm and 70 cm high. The new high-density U 3 Si/Al dispersion fuel of about 45% enrichment is contained in 20 concentric fuel plate rings. The compact core is surrounded by a large heavy-water tank which will incorporate the user installations (beam tubes and irradiation channels). However, the primary cooling circuit will contain light water which is not only more economic but also essential for the performance of the small core. An important optimization potential to decrease easily the power density peaks in the core is to reduce further the enrichment in those fuel plate rings where the neutron flux is particularly high. Two-dimensional neutron transport calculations show that such a core, containing about 7.5 kg 235 U, should have an effective multiplication factor of about 1.22 and an unperturbed but realistic maximum thermal neutron flux in the heavy water tank of 7 to 8x10 14 cm -2 .s -1 at 20 MW reactor power. (author)

Milling Behavior of Matrix Graphite Powders with Different Binder Materials in HTGR Fuel Element Fabrication: I. Variation in Particle Size Distribution

International Nuclear Information System (INIS)

Lee, Young Woo; Cho, Moon Sung

2011-01-01

The fuel element for HTGR is manufactured by mixing coated fuel particles with matrix graphite powder and forming into either pebble type or cylindrical type compacts depending on their use in different HTGR cores. The coated fuel particle, the so-called TRISO particle, consists of 500-μm spherical UO 2 particles coated with the low density buffer Pyrolytic Carbon (PyC) layer, the inner and outer high density PyC layer and SiC layer sandwiched between the two inner and outer PyC layers. The coated TRISO particles are mixed with a matrix graphite powder properly prepared and pressed into a spherical shape or a cylindrical compact finally heat-treated at about 1900 .deg. C. These fuel elements can have different sizes and forms of compact. The basic steps for manufacturing a fuel element include preparation of graphite matrix powder, overcoating the fuel particles, mixing the fuel particles with a matrix powder, carbonizing green compact, and the final high-temperature heat treatment of the carbonized fuel compact. In order to develop a fuel compact fabrication technology, it is important to develop a technology to prepare the matrix graphite powder (MGP) with proper characteristics, which has a strong influence on further steps and the material properties of fuel element. In this work, the milling behavior of matrix graphite powder mixture with different binder materials and their contents was investigated by analyzing the change in particle size distribution with different milling time

Econometric comparisons of liquid rocket engines for dual-fuel advanced earth-to-orbit shuttles

Science.gov (United States)

Martin, J. A.

1978-01-01

Econometric analyses of advanced Earth-to-orbit vehicles indicate that there are economic benefits from development of new vehicles beyond the space shuttle as traffic increases. Vehicle studies indicate the advantage of the dual-fuel propulsion in single-stage vehicles. This paper shows the economic effect of incorporating dual-fuel propulsion in advanced vehicles. Several dual-fuel propulsion systems are compared to a baseline hydrogen and oxygen system.

Callus Distraction Versus Single-Stage Lengthening With Bone Graft for Treatment of Brachymetatarsia: A Systematic Review.

Science.gov (United States)

Jones, Marc D; Pinegar, David M; Rincker, Sarah A

2015-01-01

Brachymetatarsia deformity is a cosmetically displeasing anomaly that can become physically symptomatic. The surgical techniques most commonly used to repair the anomaly include single-stage lengthening with a bone graft, callus distraction, or a combination of bone grafting and callus distraction. A systematic review of the published data was performed to compare the outcomes of these 3 surgical procedures. A total of 61 studies reporting the use of callus distraction or single-stage lengthening, or both, for the treatment of brachymetatarsia were included in the present review. The incidence of major postoperative complications after callus distraction, single-stage lengthening, and the combination procedure was 49 (12.62%), 13 (3.72%), and 3 (33.33%), respectively. The number of minor complications with callus distraction, single-stage lengthening, and the combination procedure was 152 (39.18%), 55 (15.76%), and 1 (11.11%); the mean percentage of the original length achieved was 37.36%, 25.98% and 36.00%; and the mean length achieved was 17.5, 13.2, and 14.0 mm, respectively. The healing index (mo/cm) and healing time was 2.31 and 16.04 weeks, 1.90 and 9.35 weeks, and 3.93 and 14.62 weeks for callus distraction, single-stage lengthening, and the combination procedure, respectively. Our findings indicate that the callus distraction technique is associated with greater length gained but results in greater complication rates and requires almost twice the time to heal. Single-stage lengthening with a bone graft was associated with fewer complications and faster healing times than callus distraction but with lesser gains in length. From the information reported in the studies we reviewed, the prevalence of bilateral brachymetatarsia was 44.52%, and the female/male ratio was 13.7:1. Both of these findings seem to contradict the usual data given (72% for bilateral brachymetatarsia and a female/male ratio of 25:1). Copyright © 2015 American College of Foot and

Investigation on utilization of biogas and Karanja oil biodiesel in dual fuel mode in a single cylinder DI diesel engine

Energy Technology Data Exchange (ETDEWEB)

Prasanna Pattanaik, Bhabani; Nayak, Chandrakanta [Department of Mechanical Eng., Gandhi Institute for Technological Advancement, Madanpur, Bhubaneswar - 752054, Odisha (India); Kumar Nanda, Basanta [Department of Mechanical Eng., Maharaja Institute of Technology, Bhubaneswar, Odisha (India)

2013-07-01

In this work, experiments were performed on a single cylinder DI diesel engine by using bio-gas as a primary fuel and Karanja oil biodiesel and diesel oil as secondary fuels in dual fuel operation. The experiments were performed to measure performance parameters i.e. (brake specific fuel consumption, brake thermal efficiency and exhaust gas temperature) and emission parameters such as carbon monoxide, carbon dioxide, nitrogen oxide unburned hydro carbon and smoke etc. at different load conditions. For the dual-fuel system, the intake system of the test engine was modified to convert into biogas and biodiesel of a dual-fueled combustion engine. Biogas was injected during the intake process by gas injectors. The study showed that, the engine performance parameters like BP, BTE and EGT gradually increase with increase in engine load for all test conditions using both pilot fuels diesel and KOBD. However, the BSFC of the engine showed decreasing slope with increase in engine load for all test conditions. Above 40% engine load the BSFC values for all test fuels are very close to each other. The engine emission analysis showed that the CO2, CO and NOx emissions increase with increase in engine load for both single and dual fuel mode operation using both pilot fuels. The NOx concentration of exhaust gases in dual fuel mode is superior than that of single mode.

CFD simulations of compressed air two stage rotary Wankel expander – Parametric analysis

International Nuclear Information System (INIS)

Sadiq, Ghada A.; Tozer, Gavin; Al-Dadah, Raya; Mahmoud, Saad

2017-01-01

Highlights: • CFD ANSYS-Fluent 3D simulation of Wankel expander is developed. • Single and two-stage expander’s performance is compared. • Inlet and outlet ports shape and configurations are investigated. • Isentropic efficiency of two stage Wankel expander of 91% is achieved. - Abstract: A small scale volumetric Wankel expander is a powerful device for small-scale power generation in compressed air energy storage (CAES) systems and Organic Rankine cycles powered by different heat sources such as, biomass, low temperature geothermal, solar and waste heat leading to significant reduction in CO_2 emissions. Wankel expanders outperform other types of expander due to their ability to produce two power pulses per revolution per chamber additional to higher compactness, lower noise and vibration and lower cost. In this paper, a computational fluid dynamics (CFD) model was developed using ANSYS 16.2 to simulate the flow dynamics for a single and two stage Wankel expanders and to investigate the effect of port configurations, including size and spacing, on the expander’s power output and isentropic efficiency. Also, single-stage and two-stage expanders were analysed with different operating conditions. Single-stage 3D CFD results were compared to published work showing close agreement. The CFD modelling was used to investigate the performance of the rotary device using air as an ideal gas with various port diameters ranging from 15 mm to 50 mm; port spacing varying from 28 mm to 66 mm; different Wankel expander sizes (r = 48, e = 6.6, b = 32) mm and (r = 58, e = 8, b = 40) mm both as single-stage and as two-stage expanders with different configurations and various operating conditions. Results showed that the best Wankel expander design for a single-stage was (r = 48, e = 6.6, b = 32) mm, with the port diameters 20 mm and port spacing equal to 50 mm. Moreover, combining two Wankel expanders horizontally, with a larger one at front, produced 8.52 kW compared

Baking process of thin plate carbonaceous compact

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Yoshio; Shimada, Toyokazu

1987-06-27

As a production process of a thin plate carbonaceous compact for separator of phosphoric acid fuel cell, there is a process to knead carbonaceous powder and thermosetting resin solution, to form and harden the kneaded material and then to bake, carbonize and graphitize it. However in this baking and carbonization treatment, many thin plate compacts are set in a compiled manner within a heating furnace and receive a heat treatment from their circumference. Since the above compacts to be heated tend generally to be heated from their peripheries, their baked conditions are not homogeneous easily causing the formation of cracks, etc.. As a process to heat and bake homogeneously by removing the above problematical points, this invention offers a process to set in a heating furnace a laminate consisting of the lamination of thin plate carbonaceous compacts and the heat resistant soaking plates which hold the upper and lower ends of the above lamination, to fill the upper and under peripheries of the laminate above with high heat conductive packing material and its side periphery with low heat conductive packing material respectively and to heat and sinter it. In addition, the invention specifies the high and low heat conductive packing materials respectively. (1 fig, 2 tabs)

Fill Rates of Single-Stage and Multistage Supply Systems

OpenAIRE

Matthew J. Sobel

2004-01-01

A supply system's fill rate is the fraction of demand that is met from on-hand inventory. This paper presents formulas for the fill rate of periodic review supply systems that use base-stock-level policies. The first part of the paper contains fill-rate formulas for a single-stage system and general distributions of demand. When demand is normally distributed, an exact expression uses only the standard normal distribution and density functions, and a good approximation uses only the standard ...

Management of wastes from the nuclear fuel cycle

International Nuclear Information System (INIS)

Heafield, W.; Barlow, P.

1988-01-01

The management of wastes from the nuclear fuel cycle is a key activity which affects all stages of the cycle and in which there is intense public interest, particularly at the culmination of waste management activities where dispersal and disposal are practised or are proposed. The different categories of waste are considered - high, intermediate and low level. A description is given of how and where in the fuel cycle they are produced, giving indications of volumes and activities. The fundamental objectives of waste management are reviewed and the application of these objectives to select practicable waste management processes, covering process systems product and safety considerations is discussed. Current technology can deal with the wastes now in storage, those which will be generated from oxide fuel reprocessing and future decommissioning activities; examples of these technologies, ranging from compaction and incineration for low level waste, encapsulation for intermediate level waste through to vitrification for high level waste, are described. The specific objectives relating to disposal are considered in the context of international co-operation on development and national strategies aimed at providing safe, deep repositories over the next 20 years. (author)

Fuel management of HTR-10

International Nuclear Information System (INIS)

Wu Zongxin; Jing Xingqing

2001-01-01

The 10 MW high temperature cooled reactor (HTR-10) built in Tsinghua University is a pebble bed type of HTGR. The continuous recharge and multiple-pass of spherical fuel elements are used for fuel management. The initiative stage of core is composed of the mix of spherical fuel elements and graphite elements. The equilibrium stage of core is composed of identical spherical fuel elements. The fuel management during the transition from the initiative stage to the equilibrium stage is a key issue for HTR-10 physical design. A fuel management strategy is proposed based on self-adjustment of core reactivity. The neutron physical code is used to simulate the process of fuel management. The results show that the graphite elements, the recharging fuel elements below the burn-up allowance, and the discharging fuel elements over the burn-up allowance could be identified by burn-up measurement. The maximum of burn-up fuel elements could be controlled below the burn-up limit

Soil compaction and growth of woody plants

Energy Technology Data Exchange (ETDEWEB)

Kozlowski, T.T. [Univ. of California, Berkeley (United States). Dept. of Environmental Science, Policy and Management

1999-07-01

Although soil compaction in the field may benefit or inhibit the growth of plants, the harmful effects are much more common. This paper emphasizes the deleterious effects of predominantly high levels of soil compaction on plant growth and yield. High levels of soil compaction are common in heavily used recreation areas, construction sites, urban areas, timber harvesting sites, fruit orchards, agroforestry systems and tree nurseries. Compaction can occur naturally by settling or slumping of soil or may be induced by tillage tools, heavy machinery, pedestrian traffic, trampling by animals and fire. Compaction typically alters soil structure and hydrology by increasing soil bulk density; breaking down soil aggregates; decreasing soil porosity, aeration and infiltration capacity; and by increasing soil strength, water runoff and soil erosion. Appreciable compaction of soil leads to physiological dysfunctions in plants. Often, but not always, reduced water absorption and leaf water deficits develop. Soil compaction also induces changes in the amounts and balances of growth hormones in plants, especially increases in abscisic acid and ethylene. Absorption of the major mineral nutrients is reduced by compaction of both surface soils and subsoils. The rate of photosynthesis of plants growing in very compacted soil is decreased by both stomatal and non-stomatal inhibition. Total photosynthesis is reduced as a result of smaller leaf areas. As soils become increasingly compacted respiration of roots shifts toward an anaerobic state. Severe soil compaction adversely influences regeneration of forest stands by inhibiting seed germination and growth of seedlings, and by inducing seedling mortality. Growth of woody plants beyond the seedling stage and yields of harvestable plant products also are greatly decreased by soil compaction because of the combined effects of high soil strength, decreased infiltration of water and poor soil aeration, all of which lead to a decreased

Soil compaction and growth of woody plants

International Nuclear Information System (INIS)

Kozlowski, T.T.

1999-01-01

Although soil compaction in the field may benefit or inhibit the growth of plants, the harmful effects are much more common. This paper emphasizes the deleterious effects of predominantly high levels of soil compaction on plant growth and yield. High levels of soil compaction are common in heavily used recreation areas, construction sites, urban areas, timber harvesting sites, fruit orchards, agroforestry systems and tree nurseries. Compaction can occur naturally by settling or slumping of soil or may be induced by tillage tools, heavy machinery, pedestrian traffic, trampling by animals and fire. Compaction typically alters soil structure and hydrology by increasing soil bulk density; breaking down soil aggregates; decreasing soil porosity, aeration and infiltration capacity; and by increasing soil strength, water runoff and soil erosion. Appreciable compaction of soil leads to physiological dysfunctions in plants. Often, but not always, reduced water absorption and leaf water deficits develop. Soil compaction also induces changes in the amounts and balances of growth hormones in plants, especially increases in abscisic acid and ethylene. Absorption of the major mineral nutrients is reduced by compaction of both surface soils and subsoils. The rate of photosynthesis of plants growing in very compacted soil is decreased by both stomatal and non-stomatal inhibition. Total photosynthesis is reduced as a result of smaller leaf areas. As soils become increasingly compacted respiration of roots shifts toward an anaerobic state. Severe soil compaction adversely influences regeneration of forest stands by inhibiting seed germination and growth of seedlings, and by inducing seedling mortality. Growth of woody plants beyond the seedling stage and yields of harvestable plant products also are greatly decreased by soil compaction because of the combined effects of high soil strength, decreased infiltration of water and poor soil aeration, all of which lead to a decreased

A gas puff experiment for partial simulation of compact toroid formation on MARAUDER

International Nuclear Information System (INIS)

Englert, S.E.; Englert, T.J.; Degnan, J.H.; Gahl, J.M.

1994-01-01

Preliminary results will be reported of a single valve gas puff experiment to determine spatial and spectral distribution of a gas during the early ionization stages. This experiment has been developed as a diagnostic test-bed for partial simulation of compact toroid formation on MARAUDER. The manner in which the experimental hardware has been designed allows for a wide range of diagnostic access to evaluate early time evolution of the ionization process. This evaluation will help contribute to a clearer understanding of the initial conditions for the formation stage of the compact toroid in the MARAUDER experiment, where 60 of the same puff valves are used. For the experiment, a small slice of the MARAUDER cylindrical gas injection and expansion region geometry have been re-created but in cartesian coordinates. All of the conditions in the experiment adhere as closely as possible to the MARAUDER experiment. The timing, current rise time, capacitance, resistance and inductance are appropriate to both the simulation of one of the 60 puff valves and current delivery to the load. Both time-resolved images and spectral data have been gathered for visible light emission of the plasma. Processed images reveal characteristics of spatial distribution of the current. Spectral data provide information with respect to electron temperature and density, and entrainment of contaminants

Planck 2015 results: XXVI. The Second Planck Catalogue of Compact Sources

DEFF Research Database (Denmark)

Ade, P. A R; Aghanim, N.; Arguëso, F.

2016-01-01

The Second Planck Catalogue of Compact Sources is a list of discrete objects detected in single-frequency maps from the full duration of the Planck mission and supersedes previous versions. It consists of compact sources, both Galactic and extragalactic, detected over the entire sky. Compact sour...

Design methodology of single-feed compact near-isotropic antenna design

KAUST Repository

Su, Zhen

2017-06-07

The abundance of mobile wireless devices is giving rise to a new paradigm known as Internet of Things. In this paradigm, wireless devices will be everywhere and communicating with each other. Since they will be oriented randomly in the environment, they should be able to communicate equally in all directions in order to have stable communication link. Hence, compact near isotropic antennas are required, which can enable orientation insensitive communication. In this paper, we propose a simple design methodology to design a compact near-isotropic wire antenna based on equal vector potentials. As a proof of concept, a quarter wavelength monopole antennas has been designed that is wrapped on a 3D-printed box keeping the vector potentials in three orthogonal different directions equal. By optimizing the dimension of the antenna arms, a nearly isotropic radiation pattern is thus achieved. The results show that the antenna has a maximum gain of 2.2dBi at 900 MHz with gain derivation of 9.4dB.

Development of dynamic simulation code for fuel cycle of fusion reactor. 1. Single pulse operation simulation

Energy Technology Data Exchange (ETDEWEB)

Aoki, Isao; Seki, Yasushi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Sasaki, Makoto; Shintani, Kiyonori; Kim, Yeong-Chan

1997-11-01

A dynamic simulation code for the fuel cycle of a fusion experimental reactor has been developed. The code follows the fuel inventory change with time in the plasma chamber and the fuel cycle system during a single pulse operation. The time dependence of the fuel inventory distribution is evaluated considering the fuel burn and exhaust in the plasma chamber, purification and supply functions. For each subsystem of the plasma chamber and the fuel cycle system, the fuel inventory equation is written based on the equation of state considering the function of fuel burn, exhaust, purification, and supply. The processing constants of subsystem for the steady states were taken from the values in the ITER Conceptual Design Activity (CDA) report. Using the code, the time dependence of the fuel supply and inventory depending on the burn state and subsystem processing functions are shown. (author)

Diffusion of uranium in compacted sodium bentonite

International Nuclear Information System (INIS)

Muurinen, A.; Lehikoinen, J.

1992-09-01

In the study the diffusion of uranium dissolved from uranium oxide fuel was studied experimentally in compacted sodium bentonite (Wyoming bentonite MX-80). The experiments were carried out by the through-diffusion method. The parameters varied in the study were the density of bentonite, salt content of the solution and redox conditions. Uranium was dissolved under aerobic conditions in order to simulate oxic conditions possibly caused by radiolysis in the repository

Land subsidence and hydrodynamic compaction of sedimentary basins

Directory of Open Access Journals (Sweden)

H. Kooi

1998-01-01

Full Text Available A one-dimensional model is used to investigate the relationship between land subsidence and compaction of basin sediments in response to sediment loading. Analysis of the model equations and numerical experiments demonstrate quasi-linear systems behaviour and show that rates of land subsidence due to compaction: (i can attain a significant fraction (>40% of the long-term sedimentation rate; (ii are hydrodynamically delayed with respect to sediment loading. The delay is controlled by a compaction response time τc that can reach values of 10-5-107 yr for thick shale sequences. Both the behaviour of single sediment layers and multiple-layer systems are analysed. Subsequently the model is applied to the coastal area of the Netherlands to illustrate that lateral variability in compaction-derived land subsidence in sedimentary basins largely reflects the spatial variability in both sediment loading and compaction response time. Typical rates of compaction-derived subsidence predicted by the model are of the order of 0.1 mm/yr but may reach values in excess of 1 mm/yr under favourable conditions.

Coupling of a 2.5 kW steam reformer with a 1 kW el PEM fuel cell

Science.gov (United States)

Mathiak, J.; Heinzel, A.; Roes, J.; Kalk, Th.; Kraus, H.; Brandt, H.

The University of Duisburg-Essen has developed a compact multi-fuel steam reformer suitable for natural gas, propane and butane. This steam reformer was combined with a polymer electrolyte membrane fuel cell (PEM FC) and a system test of the process chain was performed. The fuel processor comprises a prereformer step, a primary reformer, water gas shift reactors, a steam generator, internal heat exchangers in order to achieve an optimised heat integration and an external burner for heat supply as well as a preferential oxidation step (PROX) as CO purification. The fuel processor is designed to deliver a thermal hydrogen power output from 500 W to 2.5 kW. The PEM fuel cell stack provides about 1 kW electrical power. In the following paper experimental results of measurements of the single components PEM fuel cell and fuel processor as well as results of the coupling of both to form a process chain are presented.

Burnable poison fuel element and its fabrication

International Nuclear Information System (INIS)

Zukeran, Atsushi; Inoue, Kotaro; Aizawa, Hiroko.

1985-01-01

Purpose: To enable to optionally vary the excess reactivity and fuel reactivity. Method: Burnable poisons with a large neutron absorption cross section are contained in fuel material, by which the excess reactivity at the initial stage in the reactor is suppressed by the burnable poisons and the excess reactivity is released due to the reduction in the atomic number density of the burnable poisons accompanying the burning. The burnable poison comprises spherical or rod-like body made of a single material or spherical or rod-like member made of a plurality kind of materials laminated in a layer. These spheres or rods are dispersed in the fuel material. By adequately selecting the shape, combination and the arrangement of the burnable poisons, the axial power distribution of the fuel rods are flattened. (Moriyama, K.)

Micro-Fuel Cells{sup TM} for portable electronics

Energy Technology Data Exchange (ETDEWEB)

Hockaday, R.G.; DeJohn, M.; Navas, C.; Turner, P.S.; Vaz, H.L.; Vazul, L.L. [Energy Related Devices Inc., Los Alamos, NM (United States)

2000-05-01

The Micro-Fuel Cell{sup TM} is a new power supply which provides a superior alternative compared to rechargeable batteries. A prototype has been developed by Manhattan Scientifics Inc. in collaboration with Energy Related Devices Inc. This mass-producible high-energy power supply can be used for cellular telephones, portable computers and other portable devices. Instead of being recharged, it can be easily refueled with methanol. The approach taken in designing this product was to develop a competitive product with definite advantages over existing products. The Micro-Fuel Cell{sup TM} is based on the idea that a fuel cell can be built onto an engineered microplastic substrate. In this case, the integrated design makes use of thin film vacuum deposition techniques to coat patterned, etched-nuclear-particle-track plastic membranes. This process forms catalytically active surface area electrodes on either side of a single structured proton-exchange-membrane electrolyte. Methanol was the choice fuel for this system because compared to hydrogen and metal hydrides, it was considered to be safer and more compact. In addition, the theoretical specific energy of methanol is significantly higher than for lithium-ion batteries. The problem of crossover, whereby methanol fuel diffuses across the fuel cell from the anode to the cathode, has also been solved by using a selectively permeable membrane. 5 refs., 4 figs.

Ceramography of Irradiated tristructural isotropic (TRISO) Fuel from the AGR-2 Experiment

Energy Technology Data Exchange (ETDEWEB)

Rice, Francine Joyce [Idaho National Lab. (INL), Idaho Falls, ID (United States); Stempien, John Dennis [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2016-09-01

Ceramography was performed on cross sections from four tristructural isotropic (TRISO) coated particle fuel compacts taken from the AGR-2 experiment, which was irradiated between June 2010 and October 2013 in the Advanced Test Reactor (ATR). The fuel compacts examined in this study contained TRISO-coated particles with either uranium oxide (UO2) kernels or uranium oxide/uranium carbide (UCO) kernels that were irradiated to final burnup values between 9.0 and 11.1% FIMA. These examinations are intended to explore kernel and coating morphology evolution during irradiation. This includes kernel porosity, swelling, and migration, and irradiation-induced coating fracture and separation. Variations in behavior within a specific cross section, which could be related to temperature or burnup gradients within the fuel compact, are also explored. The criteria for categorizing post-irradiation particle morphologies developed for AGR-1 ceramographic exams, was applied to the particles in the AGR-2 compacts particles examined. Results are compared with similar investigations performed as part of the earlier AGR-1 irradiation experiment. This paper presents the results of the AGR-2 examinations and discusses the key implications for fuel irradiation performance.

High peak-power kilohertz laser system employing single-stage multi-pass amplification

Science.gov (United States)

Shan, Bing; Wang, Chun; Chang, Zenghu

2006-05-23

The present invention describes a technique for achieving high peak power output in a laser employing single-stage, multi-pass amplification. High gain is achieved by employing a very small "seed" beam diameter in gain medium, and maintaining the small beam diameter for multiple high-gain pre-amplification passes through a pumped gain medium, then leading the beam out of the amplifier cavity, changing the beam diameter and sending it back to the amplifier cavity for additional, high-power amplification passes through the gain medium. In these power amplification passes, the beam diameter in gain medium is increased and carefully matched to the pump laser's beam diameter for high efficiency extraction of energy from the pumped gain medium. A method of "grooming" the beam by means of a far-field spatial filter in the process of changing the beam size within the single-stage amplifier is also described.

Region-based Image Segmentation by Watershed Partition and DCT Energy Compaction

Directory of Open Access Journals (Sweden)

Chi-Man Pun

2012-02-01

Full Text Available An image segmentation approach by improved watershed partition and DCT energy compaction has been proposed in this paper. The proposed energy compaction, which expresses the local texture of an image area, is derived by exploiting the discrete cosine transform. The algorithm is a hybrid segmentation technique which is composed of three stages. First, the watershed transform is utilized by preprocessing techniques: edge detection and marker in order to partition the image in to several small disjoint patches, while the region size, mean and variance features are used to calculate region cost for combination. Then in the second merging stage the DCT transform is used for energy compaction which is a criterion for texture comparison and region merging. Finally the image can be segmented into several partitions. The experimental results show that the proposed approach achieved very good segmentation robustness and efficiency, when compared to other state of the art image segmentation algorithms and human segmentation results.

Thermo-Fluid Verification of Fuel Column with Crossflow Gap

International Nuclear Information System (INIS)

Lee, Sung Nam; Tak, Nam Il; Kim, Min Hwan; Noh, Jae Man

2013-01-01

Korea Atomic Energy Research Institute (KAERI) has been developing thermal-hydraulic code to design a safe and effective VHTR. Core reliable Optimization and Network thermo-fluid Analysis (CORONA) is a code that solves the fluid region as 1-D and the solid domain as 3-D. The postulated event is modeled to secure safety during design process. The reactor core of VHTR is piled with multi-fuel block layers. The helium gas goes through coolant channel holes after distributed from upper plenum. The fuel blocks are irradiated during operation and there might be cross gaps between blocks. These cross gaps change the passage of coolant channels and could affect the temperature of fuel compact. Therefore, two types of single fuel assembly (i. e., standard and Reserved Shutdown Control (RSC) hole fuel assemblies) were investigated in this study. The CORONA, thermo-fluid analysis code, has been developing to compute the reactor core of VHTR. Crossflow model was applied to predict temperature and flow distribution between fuel blocks in this study. The calculated results are compared with the data of commercial software, CFX. The temperature variations along the axial direction well agree for both standard / RSC fuel assemblies. The flow redistribution due to crossflow matches well. The hot spot temperature and locations might differ depending on the cross gap size. This research will be done in detail for further study

Microstructural evolution and Am migration behaviour in Am-containing fuels at the initial stage of irradiation

International Nuclear Information System (INIS)

Tanaka, Kosuke; Miwa, Shuhei; Sato, Isamu; Osaka, Masahiko; Hirosawa, Takashi; Obayashi, Hiroshi; Koyama, Shin-ichi; Yoshimochi, Hiroshi; Tanaka, Kenya

2010-01-01

In order to investigate the effect of americium addition to MOX fuels on the irradiation behaviour, the 'Am-1' programme is being conducted in JAEA. The Am-1 programme consists of two short-term irradiation tests of 10-minute and 24-hour irradiations and a steady-state irradiation test. The short-term irradiation tests were successfully completed and the post-irradiation examinations (PIE) are in progress. The PIE for Am-containing MOX fuels focused on the microstructural evolution and redistribution behaviour of Am at the initial stage of irradiation and the results to date are reported. The successful development of fabrication technology with remote handling and the evaluation of thermo-chemical properties based on the out-of-pile experiments are described with an emphasis on the effects of Am addition on the MOX fuel properties. (authors)

Compact very low temperature scanning tunneling microscope with mechanically driven horizontal linear positioning stage.

Science.gov (United States)

Suderow, H; Guillamon, I; Vieira, S

2011-03-01

We describe a scanning tunneling microscope for operation in a dilution refrigerator with a sample stage which can be moved macroscopically in a range up to a cm and with an accuracy down to the tens of nm. The position of the tip over the sample as set at room temperature does not change more than a few micrometers when cooling down. This feature is particularly interesting for work on micrometer sized samples. Nanostructures can be also localized and studied, provided they are repeated over micrometer sized areas. The same stage can be used to approach a hard single crystalline sample to a knife and cleave it, or break it, in situ. In situ positioning is demonstrated with measurements at 0.1 K in nanofabricated samples. Atomic resolution down to 0.1 K and in magnetic fields of 8 T is demonstrated in NbSe(2). No heat dissipation nor an increase in mechanical noise has been observed at 0.1 K when operating the slider.

Theoretical evaluation of the efficiency of gas single-stage reciprocating compressor medium pressure units

Science.gov (United States)

Busarov, S. S.; Vasil'ev, V. K.; Busarov, I. S.; Titov, D. S.; Panin, Ju. N.

2017-08-01

Developed earlier and tested in such working fluid as air, the technology of calculating the operating processes of slow-speed long-stroke reciprocating stages let the authors to obtain successful results concerning compression of gases to medium pressures in one stage. In this connection, the question of the efficiency of the application of slow-speed long-stroke stages in various fields of technology and the national economy, where the working fluid is other gas or gas mixture, is topical. The article presents the results of the efficiency evaluation of single-stage compressor units on the basis of such stages for cases when ammonia, hydrogen, helium or propane-butane mixture is used as the working fluid.

Density determination of sintered ceramic nuclear fuel materials

International Nuclear Information System (INIS)

Landspersky, H.; Medek, J.

1980-01-01

The feasibility was tested of using solids for pycnometric determination of the density of uranium dioxide-based sintered ceramic fuel materials manufactured by the sol-gel method in the shape of spherical particles of 0.7 to 1.0 mm in size and of particles smaller than 200 μm. For fine particles, this is the only usable method of determining their density which is a very important parameter of the fine fraction when it is employed for the manufacture of fuel elements by vibration compacting. The method consists in compacting a mixture of pycnometric material and dispersed particles of uranium dioxide, determining the size and weight of the compact, and in calculating the density of the material measured from the weight of the oxide sample in the mixture. (author)

Irradiation performance of AGR-1 high temperature reactor fuel

Energy Technology Data Exchange (ETDEWEB)

Demkowicz, Paul A., E-mail: paul.demkowicz@inl.gov [Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-6188 (United States); Hunn, John D. [Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831-6093 (United States); Ploger, Scott A. [Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-6188 (United States); Morris, Robert N.; Baldwin, Charles A. [Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831-6093 (United States); Harp, Jason M.; Winston, Philip L. [Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-6188 (United States); Gerczak, Tyler J. [Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831-6093 (United States); Rooyen, Isabella J. van [Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-6188 (United States); Montgomery, Fred C.; Silva, Chinthaka M. [Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831-6093 (United States)

2016-09-15

Highlights: • Post-irradiation examination was performed on AGR-1 coated particle fuel. • Cesium release from the particles was very low in the absence of failed SiC layers. • Silver release was often substantial, and varied considerably with temperature. • Buffer and IPyC layers were found to play a key role in TRISO coating behavior. • Fission products palladium and silver were found in the SiC layer of particles. - Abstract: The AGR-1 experiment contained 72 low-enriched uranium oxide/uranium carbide TRISO coated particle fuel compacts in six capsules irradiated to burnups of 11.2 to 19.6% FIMA, with zero TRISO coating failures detected during the irradiation. The irradiation performance of the fuel including the extent of fission product release and the evolution of kernel and coating microstructures was evaluated based on detailed examination of the irradiation capsules, the fuel compacts, and individual particles. Fractional release of {sup 110m}Ag from the fuel compacts was often significant, with capsule-average values ranging from 0.01 to 0.38. Analysis of silver release from individual compacts indicated that it was primarily dependent on fuel temperature history. Europium and strontium were released in small amounts through intact coatings, but were found to be significantly retained in the outer pyrocarbon and compact matrix. The capsule-average fractional release from the compacts was 1 × 10{sup −4} to 5 × 10{sup −4} for {sup 154}Eu and 8 × 10{sup −7} to 3 × 10{sup −5} for {sup 90}Sr. The average {sup 134}Cs fractional release from compacts was <3 × 10{sup −6} when all particles maintained intact SiC. An estimated four particles out of 2.98 × 10{sup 5} in the experiment experienced partial cesium release due to SiC failure during the irradiation, driving {sup 134}Cs fractional release in two capsules to approximately 10{sup −5}. Identification and characterization of these particles has provided unprecedented insight into

Mass-transfer in extraction and reextraction as a single-stage process

International Nuclear Information System (INIS)

Rodriguez del Cerro, M.; Trilleros, J.A.; Otero de la Gandara, J.L.

1987-01-01

The rate of mass transfer between water and naftenic acid and threebutilphosphate in kerosen are studied in the two possibilities to or from water. The two insoluble phases are brought in to intimate contact with dispersed phase droplets, in a single-stage process. The evolution of the equilibrium distribution of solute is taken in consideration. (author)

Millijoule Pulse Energy Second Harmonic Generation With Single-Stage Photonic Bandgap Rod Fiber Laser

DEFF Research Database (Denmark)

Laurila, Marko; Saby, Julien; Alkeskjold, Thomas Tanggaard

2011-01-01

In this paper, we demonstrate, for the first time, a single-stage Q-switched single-mode (SM) ytterbium-doped rod fiber laser delivering record breaking pulse energies at visible and UV light. We use a photonic bandgap rod fiber with a mode field diameter of 59μm based on a new distributed...

A high-order positivity-preserving single-stage single-step method for the ideal magnetohydrodynamic equations

Science.gov (United States)

Christlieb, Andrew J.; Feng, Xiao; Seal, David C.; Tang, Qi

2016-07-01

We propose a high-order finite difference weighted ENO (WENO) method for the ideal magnetohydrodynamics (MHD) equations. The proposed method is single-stage (i.e., it has no internal stages to store), single-step (i.e., it has no time history that needs to be stored), maintains a discrete divergence-free condition on the magnetic field, and has the capacity to preserve the positivity of the density and pressure. To accomplish this, we use a Taylor discretization of the Picard integral formulation (PIF) of the finite difference WENO method proposed in Christlieb et al. (2015) [23], where the focus is on a high-order discretization of the fluxes (as opposed to the conserved variables). We use the version where fluxes are expanded to third-order accuracy in time, and for the fluid variables space is discretized using the classical fifth-order finite difference WENO discretization. We use constrained transport in order to obtain divergence-free magnetic fields, which means that we simultaneously evolve the magnetohydrodynamic (that has an evolution equation for the magnetic field) and magnetic potential equations alongside each other, and set the magnetic field to be the (discrete) curl of the magnetic potential after each time step. In this work, we compute these derivatives to fourth-order accuracy. In order to retain a single-stage, single-step method, we develop a novel Lax-Wendroff discretization for the evolution of the magnetic potential, where we start with technology used for Hamilton-Jacobi equations in order to construct a non-oscillatory magnetic field. The end result is an algorithm that is similar to our previous work Christlieb et al. (2014) [8], but this time the time stepping is replaced through a Taylor method with the addition of a positivity-preserving limiter. Finally, positivity preservation is realized by introducing a parameterized flux limiter that considers a linear combination of high and low-order numerical fluxes. The choice of the free

Coupling of the four design stages in the management of nuclear fuel; Acoplamiento de las cuatro etapas de diseno en la administracion de combustible nuclear

Energy Technology Data Exchange (ETDEWEB)

Marinez R, R. L.

2016-07-01

In this work, the main characteristics of the system to solve the four stages of the nuclear fuel management are presented; the above for boiling water reactors (BWR). The novelty of the system is that a complete solution is obtained in a coupled way; the involved stages are fuel lattice design, fuel assembly design, fuel reload design and control rod pattern design. To do this, in each stage of the process some heuristics techniques are applied, and each stage has its own objective function. The used heuristic techniques are neural network and a hybrid between scatter search and path re linking for fuel lattice design; for fuel assembly design a simple local search was applied and finally, for both fuel reload and control rod pattern designs, the tabu search technique was used. The system have two loops, one external loop and one internal loop, the first one starts with fuel lattice design and concludes with control rod pattern design; on the other hand, the internal loop executes an iterative process between both fuel reload design and control rod pattern designs, to start this loop a seed fuel reload is required, which is obtained applying Haling principle. The internal loop is finished when four iterations were achieved, while the external loop is finished when two iterations were achieved, this number of iterations was fixed due to the great quantity of required computational resources. An 18- months equilibrium cycle was considered to have a reference value to compare against the obtained results with our system, this cycle have two fuel fresh batches with the same average uranium enrichment, but different gadolinia content. The above cycle achieved a 10,896 Mwd/Tu of energy and was divided into 12 burnup steps. The obtained results show the advantage to solve the complete problem in a coupled way, even though a great quantity of computational resources are used. It is necessary to note that the energy value was not achieved in all cases, only in some

Non-fuel bearing hardware melting technology

International Nuclear Information System (INIS)

Newman, D.F.

1993-01-01

Battelle has developed a portable hardware melter concept that would allow spent fuel rod consolidation operations at commercial nuclear power plants to provide significantly more storage space for other spent fuel assemblies in existing pool racks at lower cost. Using low pressure compaction, the non-fuel bearing hardware (NFBH) left over from the removal of spent fuel rods from the stainless steel end fittings and the Zircaloy guide tubes and grid spacers still occupies 1/3 to 2/5 of the volume of the consolidated fuel rod assemblies. Melting the non-fuel bearing hardware reduces its volume by a factor 4 from that achievable with low-pressure compaction. This paper describes: (1) the configuration and design features of Battelle's hardware melter system that permit its portability, (2) the system's throughput capacity, (3) the bases for capital and operating estimates, and (4) the status of NFBH melter demonstration to reduce technical risks for implementation of the concept. Since all NFBH handling and processing operations would be conducted at the reactor site, costs for shipping radioactive hardware to and from a stationary processing facility for volume reduction are avoided. Initial licensing, testing, and installation in the field would follow the successful pattern achieved with rod consolidation technology

Compaction of solid wastes in countries without disposal facility: A prelude of future troubles

International Nuclear Information System (INIS)

Benitez-Navarro, J.C.; Salgado-Mojena, M.

2002-01-01

This paper is intended to launch a technical debate, which will lead up to simple recommendations on what to do with compactable solid wastes in countries without disposal facilities. The paper discusses the problems caused by some practical uncertainties in the long-term management of the radioactive solid wastes produced outside the nuclear fuel cycle, in countries belonging to Groups A, B and C. Compaction is the preferred volume reduction method. But the compacted solid wastes are very probably not in a suitable form for future disposal and would need to be processed again in the near future. (author)

Safety Testing of AGR-2 UCO Compacts 6-4-2 and 2-3-1

Energy Technology Data Exchange (ETDEWEB)

Hunn, John D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Morris, Robert N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Baldwin, Charles A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Burns, Zachary M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Montgomery, Fred C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Skitt, Darren J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-08-01

Post-irradiation examination (PIE) and elevated-temperature safety testing are being performed on tristructural-isotropic (TRISO) coated-particle fuel compacts from the Advanced Gas Reactor (AGR) Fuel Development and Qualification Program second irradiation experiment (AGR-2). Details on this irradiation experiment have been previously reported [Collin 2014]. The AGR-2 PIE effort builds upon the understanding acquired throughout the AGR-1 PIE campaign [Demkowicz et al. 2015] and is establishing a database for the different AGR-2 fuel designs.

Nuclear fuel

International Nuclear Information System (INIS)

Azevedo, J.B.L. de.

1980-01-01

All stages of nuclear fuel cycle are analysed with respect to the present situation and future perspectives of supply and demand of services; the prices and the unitary cost estimation of these stages for the international fuel market are also mentioned. From the world resources and projections of uranium consumption, medium-and long term analyses are made of fuel availability for several strategies of use of different reactor types. Finally, the cost of nuclear fuel in the generation of electric energy is calculated to be used in the energetic planning of the electric sector. (M.A.) [pt

Fuel assembly

International Nuclear Information System (INIS)

Watanabe, Shoichi; Hirano, Yasushi.

1998-01-01

A one-half or more of entire fuel rods in a fuel assembly comprises MOX fuel rods containing less than 1wt% of burnable poisons, and at least a portion of the burnable poisons comprises gadolinium. Then, surplus reactivity at an initial stage of operation cycle is controlled to eliminate burnable poisons remained unburnt at a final stage, as well as increase thermal reactivity. In addition, the content of fission plutonium is determined to greater than the content of uranium 235, and fuel rods at corner portions are made not to incorporate burnable poisons. Fuel rods not containing burnable poisons are disposed at positions in adjacent with fuel rods facing to a water rod at one or two directions. Local power at radial center of the fuel assembly is increased to flatten the distortion of radial power distribution. (N.H.)

A compact, all-optical, THz wave generator based on self-modulation in a slab photonic crystal waveguide with a single sub-nanometer graphene layer.

Science.gov (United States)

Asadi, R; Ouyang, Z; Mohammd, M M

2015-07-14

We design a compact, all-optical THz wave generator based on self-modulation in a 1-D slab photonic crystal (PhC) waveguide with a single sub-nanometer graphene layer by using enhanced nonlinearity of graphene. It has been shown that at the bandgap edge of higher bands of a 1-D slab PhC, through only one sub-nanometer graphene layer we can obtain a compact, high modulation factor (about 0.98 percent), self-intensity modulator at a high frequency (about 0.6 THz) and low threshold intensity (about 15 MW per square centimeter), and further a compact, all-optical THz wave generator by integrating the self-modulator with a THz photodiode or photonic mixer. Such a THz source is expected to have a relatively high efficiency compared with conventional sources based on optical methods. The proposed THz source can find wide applications in THz science and technology, e.g., in THz imaging, THz sensors and detectors, THz communication systems, and THz optical integrated logic circuits.

A Modified Nitride-Based Fuel for Long Core Life and Proliferation Resistance

International Nuclear Information System (INIS)

Ebbinghaus, B; Choi, J; Meier, T

2003-01-01

A modified nitride-based uranium fuel to support the small, secured, transportable, and autonomous reactor (SSTAR) concept is initiated at Lawrence Livermore National laboratory (LLNL). This project centers on the evaluation of modified uranium nitride fuels imbedded with other inert (e.g. ZrN), neutron-absorbing (e.g. HfN) , or breeding (e.g. ThN) nitrides to enhance the fuel properties to achieve long core life with a compact reactor design. A long-life fuel could minimize the need for on-site refueling and spent-fuel storage. As a result, it could significantly improve the proliferation resistance of the reactor/fuel systems. This paper discusses the potential benefits and detriments of modified nitride-based fuels using the criteria of compactness, long-life, proliferation resistance, fuel safety, and waste management. Benefits and detriments are then considered in recommending a select set of compositions for further study

Development of a robust and compact kerosene–diesel reaction mechanism for diesel engines

International Nuclear Information System (INIS)

Tay, Kun Lin; Yang, Wenming; Mohan, Balaji; An, Hui; Zhou, Dezhi; Yu, Wenbin

2016-01-01

Highlights: • An approach is used to develop a robust kerosene–diesel reaction mechanism. • Ignition delay of the kerosene sub-mechanism is well validated with experiments. • The kerosene sub-mechanism reproduces the flame lift-off lengths of Jet-A reasonably well. • The kerosene sub-mechanism performs reasonably well under engine conditions. - Abstract: The use of kerosene fuels in internal combustion engines is getting more widespread. The North Atlantic Treaty Organization military is pushing for the use of a single fuel on the battlefield in order to reduce logistical issues. Moreover, in some countries, fuel adulteration is a serious matter where kerosene is blended with diesel and used in diesel engines. So far, most investigations done regarding the use of kerosene fuels in diesel engines are experimental and there is negligible simulation work done in this area possibly because of the lack of a robust and compact kerosene reaction mechanism. This work focuses on the development of a small but reliable kerosene–diesel reaction mechanism, suitable to be used for diesel engine simulations. The new kerosene–diesel reaction mechanism consists only of 48 species and 152 reactions. Furthermore, the kerosene sub-mechanism in this new mechanism is well validated for its ignition delay times and has proven to replicate kerosene combustion well in a constant volume combustion chamber and an optical engine. Overall, this new kerosene–diesel reaction mechanism is proven to be robust and practical for diesel engine simulations.

Fluid dynamics simulations of a fuel processing system; Stroemungsmechanische Modellierung eines Brenngaserzeugungssystems

Energy Technology Data Exchange (ETDEWEB)

Scharf, Florian

2012-07-01

The present thesis deals with the topic of the complete fluid dynamic modelling of the key components of a fuel processing system and based on it the development of the next generation reactors. Fuel cell auxilliary power units enable an energy efficient power generation for mobile applications with higher on-board power consumption. Enabling the operation of the fuel cell with the available middle-destillate on-board, the fuel is transformed to an hydrogen-rich gas in a fuel processing system consisting of the key components autothermal reformer, water-shift reactor and catalytic burner. The modules of the fuel processing system are thereby integrated within the reactors to obtain a lightweighted and compact overall system. The complete numerical description of theses systems are based on chemical-reaction models, vaporization models of fuel and water in the integrated reactant treatment and as well on models for the integrated heat-exchanger. The strong interaction between the single reactor zones require therefore modelling of the key components as an overall reactor system. The methodology of the present thesis is based on a tight integration of CFD simulations with experimental analysis and the construction of the reactors. The results of carried out prototype testings, post-mortem-analysis and laboratory experiments are taken as basis for the CFD modelling and the reactor construction. As numerical tool for fluid dynamic modelling the CFD software FLUENT was used. In the context of this thesis the CFD modelling library was extended with the purpose of the complete description of key components in the CFD overall model. In these CFD overall models the thermal interactions between the reactor zones as well as the influence of the pulsating fuel injection and the chemical reactions are taken into account. For this purpose a similarity theoretical CFD modell of the pulsating fuel injection was generated based on results from prototype testings and high

Experimental investigations of a single cylinder genset engine with common rail fuel injection system

Directory of Open Access Journals (Sweden)

Gupta Paras

2014-01-01

Full Text Available Performance and emissions characteristics of compression ignition (CI engines are strongly dependent on quality of fuel injection. In an attempt to improve engine combustion, engine performance and reduce the exhaust emissions from a single cylinder constant speed genset engine, a common rail direct injection (CRDI fuel injection system was deployed and its injection timings were optimized. Results showed that 34°CA BTDC start of injection (SOI timings result in lowest brake specific fuel consumption (BSFC and smoke opacity. Advanced injection timings showed higher cylinder peak pressure, pressure rise rate, and heat release rate due to relatively longer ignition delay experienced.

Single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation in surgical treatment for single-segment lumbar spinal tuberculosis.

Science.gov (United States)

Zeng, Hao; Wang, Xiyang; Zhang, Penghui; Peng, Wei; Liu, Zheng; Zhang, Yupeng

2015-01-01

The aim of this study is to determine the feasibility and efficacy of surgical management of single-segment lumbar spinal tuberculosis (TB) by using single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation. Seventeen cases of single-segment lumbar TB were treated with single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation. The mean follow-up was 36.9 months (range: 24-62 months). The kyphotic angle ranged from 15.2-35.1° preoperatively, with an average measurement of 27.8°. The American Spinal Injury Association (ASIA) score system was used to evaluate the neurological deficits and erythrocyte sedimentation rate (ESR) used to judge the activity of TB. Spinal TB was completely cured in all 17 patients. There was no recurrent TB infection. The postoperative kyphotic angle was 6.6-10.2°, 8.1° in average, and there was no significant loss of the correction at final follow-up. Solid fusion was achieved in all cases. Neurological condition in all patients was improved after surgery. Single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation can be a feasible and effective method the in treatment of single-segment lumbar spinal TB.

Study on the nitride fuel fabrication for FBR cycle (1)

International Nuclear Information System (INIS)

Shinkai, Yasuo; Ono, Kiyoshi; Tanaka, Kenya

2002-07-01

In the phase-II of JNC's 'Feasibility Study on Commercialized Fuel Reactor Cycle System (the F/S)', the nitride fuels are selected as candidate for fuels for heavy metal cooled reactor, gas cooled reactor, and small scale reactor. In particular, the coated fuel particles are a promising concept for gas cooled reactor. In addition, it is necessary to study in detail the application possibility of pellet nitride fuel and vibration compaction nitride fuel for heavy metal cooled reactor and small scale reactor in the phase-II. In 2001, we studied more about additional equipments for the nitride fuel fabrication in processes from gelation to carbothermic reduction in the vibration compaction method. The result of reevaluation of off-gas mass flow around carbothermic reduction equipment in the palletizing method, showed that quantity of off-gas flow reduced and its reduction led the operation cost to decrease. We studied the possibility of fabrication of large size particles in the coated fuel particles for helium gas cooled reactor and we made basic technical issues clear. (author)

FEM modeling on the compaction of Fe and Al composite powders

Directory of Open Access Journals (Sweden)

Han P.

2015-01-01

Full Text Available The compaction process of Fe and Al composite powders subjected to single action die compaction was numerically modeled by FEM method. The relationship between the overall relative density and compaction pressure of the compacts with various Al contents was firstly identified, and the influences of Al content on the local relative density, stress, and their distributions were studied. Then the compaction pressure effects on the above properties with fixed Al content were discussed. Furthermore, detailed flow behaviors of the composite powders during compaction and the relationship between the compaction pressure and the ejection force/spring back of the compact were analyzed. The results show that: (1 With each compaction pressure, higher relative density can be realized with the increase of Al content and the relative density distribution tends to be uniform; (2 When the Al content is fixed, higher compaction pressure can lead to composite compact with higher relative density, and the equivalent Von Mises stress in the central part of the compact increases gradually; (3 Convective flow occurs at the top and bottom parts of the compact close to the die wall, each indicates a different flow behavior; (4 The larger the compaction pressure for each case, the higher the residual elasticity, and the larger the ejection force needed.

Compact cryocooler heat exchangers

International Nuclear Information System (INIS)

Luna, J.; Frederking, T.H.K.

1991-01-01

Compact heat exchangers are subject to different constraints as a room temperature gas is cooled down by a cold stream returning from a JT valve (or a similar cryoprocess component). In particular, the optimization of exchangers for liquid helium systems has to cover a wide range in temperature and density of the fluid. In the present work we address the following thermodynamic questions: 1. The optimization of intermediate temperatures which optimize stage operation (a stage is assumed to have a constant cross section); 2. The optimum temperature difference available for best overall economic performance values. The results are viewed in the context of porous media concepts applied to rather low speeds of fluid flow in narrow passages. In this paper examples of fluid/solid constraints imposed in this non-classical low temperature area are presented

250 kV 6 mA compact Cockcroft-Walton high-voltage power supply

Energy Technology Data Exchange (ETDEWEB)

Ma, Zhan-Wen; Su, Xiao-Dong; Wei, Zhen; Huang, Zhi-Wu; Miao, Tian-You; Su, Tong-Ling [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Lu, Xiao-Long; Wang, Jun-Run; Yao, Ze-En, E-mail: zeyao@lzu.edu.cn [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Engineering Research Center for Neutron Application, Ministry of Education, Lanzhou University, Lanzhou 730000 (China)

2016-08-15

A compact power supply system for a compact neutron generator has been developed. A 4-stage symmetrical Cockcroft-Walton circuit is adopted to produce 250 kV direct current high-voltage. A 2-stage 280 kV isolation transformer system is used to drive the ion source power supply. For a compact structure, safety, and reliability during the operation, the Cockcroft-Walton circuit and the isolation transformer system are enclosed in an epoxy vessel containing the transformer oil whose size is about ∅350 mm × 766 mm. Test results indicate that the maximum output voltage of the power supply is 282 kV, and the stability of the output voltage is better than 0.63% when the high voltage power supply is operated at 250 kV, 6.9 mA with the input voltage varying ±10%.

Determination of heterogeneous medium parameters by single fuel element method

International Nuclear Information System (INIS)

Veloso, M.A.F.

1985-01-01

The neutron pulse propagation technique was employed to study an heterogeneous system consisting of a single fuel element placed at the symmetry axis of a large cylindrical D 2 O tank. The response of system for the pulse propagation technique is related to the inverse complex relaxation length of the neutron waves also known as the system dispersion law ρ (ω). Experimental values of ρ (ω) were compared with the ones derived from Fermi age - Diffusion theory. The main purpose of the experiment was to obtain the Feinberg-Galanin thermal constant (γ), which is the logaritmic derivative of the neutron flux at the fuel-moderator interface and a such a main input data for heterogeneous reactor theory calculations. The γ thermal constant was determined as the number giving the best agreement between the theoretical and experimental values of ρ (ω). The simultaneous determination of two among four parameters η,ρ,τ and L s is possible through the intersection of dispersion laws of the pure moderator system and the fuel moderator system. The parameters τ and η were termined by this method. It was shown that the thermal constant γ and the product η ρ can be computed from the real and imaginary parts of the fuel-moderator dispersion law. The results for this evaluation scheme showns a not stable behavior of γ as a function of frequency, a result not foreseen by the theoretical model. (Author) [pt

Modelling of the Optical Detector System in a Compact Disc Player

DEFF Research Database (Denmark)

Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle

2003-01-01

The cross-couplings between focus and radial tracking servos in compact disc players are important, but the optical cross couplings are not well described in the literature. In this paper an optical model of a compact disc player based on the three beam single foucault detector principle is found...

Staged combustion with piston engine and turbine engine supercharger

Science.gov (United States)

Fischer, Larry E [Los Gatos, CA; Anderson, Brian L [Lodi, CA; O'Brien, Kevin C [San Ramon, CA

2011-11-01

A combustion engine method and system provides increased fuel efficiency and reduces polluting exhaust emissions by burning fuel in a two-stage combustion system. Fuel is combusted in a piston engine in a first stage producing piston engine exhaust gases. Fuel contained in the piston engine exhaust gases is combusted in a second stage turbine engine. Turbine engine exhaust gases are used to supercharge the piston engine.

Contributions to LWR spent fuel storage and transport

International Nuclear Information System (INIS)

The papers included in this document describe the aspects of spent LWR fuel storage and transport-behaviour of spent fuel during storage; use of compact storage packs; safety of storage; design of storage facilities AR and AFR; description of transport casks and transport procedures

Adaptive kanban control mechanism for a single-stage hybrid system

Science.gov (United States)

Korugan, Aybek; Gupta, Surendra M.

2002-02-01

In this paper, we consider a hybrid manufacturing system with two discrete production lines. Here the output of either production line can satisfy the demand for the same type of product without any penalties. The interarrival times for demand occurrences and service completions are exponentially distributed i.i.d. variables. In order to control this type of manufacturing system we suggest a single stage pull type control mechanism with adaptive kanbans and state independent routing of the production information.

An experimental evaluation of the Gerdemann–Jablonski compaction equation

CSIR Research Space (South Africa)

Machaka, R

2015-05-01

Full Text Available properties of the material being compacted’ falls short on Denny’s criterion[12] of an ideal multi-stage compaction equation. Thus, the underlying mechanisms driving the compaction process seemingly cannot be described completely in terms of a one...–101. 11. D. Jeyasimman, K. Sivaprasad, S. Sivasankaran, and R. Narayanasamy: Powder Technol., 2014, vol. 258, pp. 189–97. 12. P.J. Denny: Powder Technol., 2002, vol. 127 (2), pp. 162–72. 13. M. Qian: Int. J. Powder Metall., 2010, vol. 46 (5), pp. 29–44. 14...

Compacting and sintering of agglomerated ultradispersed powders ZrO2

International Nuclear Information System (INIS)

Galakhov, A.V.; Vyazov, I.V.; Shevchenko, V.Ya.

1989-01-01

Results of investigation into the change of porous structure of shapings of submicron powders under compacting and its effect on the sintering kinetics are presented. ZrO 2 + 3%Y 2 O 3 (molar share) composition powders, produced by coprecipitation from Zr and Y mineral salts are used. Reduction of specific volume of interagglomerated pores is linked with the destruction of large soft agglomerates at the initial compacting shift. At this stage the filling of a part of interagglomerated pores with large agglomerate crushing products takes place. As a result of such a process a part of pores transfers from the class of interagglomerated to the class of intraagglomerated ones increasing their specific content in a compact

New current control based MPPT technique for single stage grid connected PV systems

International Nuclear Information System (INIS)

Jain, Sachin; Agarwal, Vivek

2007-01-01

This paper presents a new maximum power point tracking algorithm based on current control for a single stage grid connected photovoltaic system. The main advantage of this algorithm comes from its ability to predict the approximate amplitude of the reference current waveform or power that can be derived from the PV array with the help of an intermediate variable β. A variable step size for the change in reference amplitude during initial tracking helps in fast tracking. It is observed that if the reference current amplitude is greater than the array capacity, the system gets unstable (i.e. moves into the positive slope region of the p-v characteristics of the array). The proposed algorithm prevents the PV system from entering the positive slope region of the p-v characteristics. It is also capable of restoring stability if the system goes unstable due to a sudden environmental change. The proposed algorithm has been tested on a new single stage grid connected PV configuration recently developed by the authors to feed sinusoidal current into the grid. The system is operated in a continuous conduction mode to realize advantages such as low device current stress, high efficiency and low EMI. A fast MPPT tracker with single stage inverter topology operating in CCM makes the overall system highly efficient. Specific cases of the system, operating in just discontinuous current mode and discontinuous current mode and their relative merits and demerits are also discussed

HTR fuel modelling with the ATLAS code. Thermal mechanical behaviour and fission product release assessment

International Nuclear Information System (INIS)

Guillermier, Pierre; Daniel, Lucile; Gauthier, Laurent

2009-01-01

To support AREVA NP in its design on HTR reactor and its HTR fuel R and D program, the Commissariat a l'Energie Atomique developed the ATLAS code (Advanced Thermal mechanicaL Analysis Software) with the objectives: - to quantify, with a statistical approach, the failed particle fraction and fission product release of a HTR fuel core under normal and accidental conditions (compact or pebble design). - to simulate irradiation tests or benchmark in order to compare measurements or others code results with ATLAS evaluation. These two objectives aim at qualifying the code in order to predict fuel behaviour and to design fuel according to core performance and safety requirements. A statistical calculation uses numerous deterministic calculations. The finite element method is used for these deterministic calculations, in order to be able to choose among three types of meshes, depending on what must be simulated: - One-dimensional calculation of one single particle, for intact particles or particles with fully debonded layers. - Two-dimensional calculations of one single particle, in the case of particles which are cracked, partially debonded or shaped in various ways. - Three-dimensional calculations of a whole compact slice, in order to simulate the interactions between the particles, the thermal gradient and the transport of fission products up to the coolant. - Some calculations of a whole pebble, using homogenization methods are being studied. The temperatures, displacements, stresses, strains and fission product concentrations are calculated on each mesh of the model. Statistical calculations are done using these results, taking into account ceramic failure mode, but also fabrication tolerances and material property uncertainties, variations of the loads (fluence, temperature, burn-up) and core data parameters. The statistical method used in ATLAS is the importance sampling. The model of migration of long-lived fission products in the coated particle and more

Compressed gas combined single- and two-stage light-gas gun

Science.gov (United States)

Lamberson, L. E.; Boettcher, P. A.

2018-02-01

With more than 1 trillion artificial objects smaller than 1 μm in low and geostationary Earth orbit, space assets are subject to the constant threat of space debris impact. These collisions occur at hypervelocity or speeds greater than 3 km/s. In order to characterize material behavior under this extreme event as well as study next-generation materials for space exploration, this paper presents a unique two-stage light-gas gun capable of replicating hypervelocity impacts. While a limited number of these types of facilities exist, they typically are extremely large and can be costly and dangerous to operate. The design presented in this paper is novel in two distinct ways. First, it does not use a form of combustion in the first stage. The projectile is accelerated from a pressure differential using air and inert gases (or purely inert gases), firing a projectile in a nominal range of 1-4 km/s. Second, the design is modular in that the first stage sits on a track sled and can be pulled back and used in itself to study lower speed impacts without any further modifications, with the first stage piston as the impactor. The modularity of the instrument allows the ability to investigate three orders of magnitude of impact velocities or between 101 and 103 m/s in a single, relatively small, cost effective instrument.

A user input manual for single fuel rod behaviour analysis code FEMAXI-III

International Nuclear Information System (INIS)

Saito, Hiroaki; Yanagisawa, Kazuaki; Fujita, Misao.

1983-03-01

Principal objectives of Safety related research in connection with lighr water reactor fuel rods under normal operating condition are mainly addressed 1) to assess fuel integrity under steady state condition and 2) to generate initial condition under hypothetical accident. These assessments have to be relied principally upon steady state fuel behaviour computing code that is able to calculate fuel conditions to tbe occurred in a various manner. To achieve these objectives, efforts have been made to develope analytical computer code that calculates in-reactor fuel rod behaviour in best estimate manner. The computer code developed for the prediction of the long-term burnup response of single fuel rod under light water reactor condition is the third in a series of code versions:FEMAMI-III. The code calculates temperature, rod internal gas pressure, fission gas release and pellet-cladding interaction related rod deformation as a function of time-dependent fuel rod power and coolant boundary conditions. This document serves as a user input manual for the code FEMAMI-III which has opened to the public in year of 1982. A general description of the code input and output are included together with typical examples of input data. A detailed description of structures, analytical submodels and solution schemes in the code shall be given in the separate document to be published. (author)

Proton exchange membrane fuel cells modeling

CERN Document Server

Gao, Fengge; Miraoui, Abdellatif

2013-01-01

The fuel cell is a potential candidate for energy storage and conversion in our future energy mix. It is able to directly convert the chemical energy stored in fuel (e.g. hydrogen) into electricity, without undergoing different intermediary conversion steps. In the field of mobile and stationary applications, it is considered to be one of the future energy solutions.Among the different fuel cell types, the proton exchange membrane (PEM) fuel cell has shown great potential in mobile applications, due to its low operating temperature, solid-state electrolyte and compactness.This book pre

Single-phase highly densified SrBi{sub 2}Ta{sub 2}O{sub 9} compacts produced by high-pressure sintering

Energy Technology Data Exchange (ETDEWEB)

Pereira, Altair Soria; Souza, Ricson Rocha de; Sousa, Vania Caldas de, E-mail: altair@if.ufrgs.br [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre (Brazil)

2016-07-01

Full text: The development of high-performance lead-free piezoelectric ceramics is an important scientific and technological challenge, as environmental and health issues have imposed restrictions to the use of lead zirconate titanates, the most employed material in ferroelectric devices [1]. Strontium bismuth tantalate (SBT),SrBi{sub 2}Ta{sub 2}O{sub 9}, is an interesting alternative ferroelectric material as its polarization can be modified at low voltages and it shows limited polarization switching fatigue. However, the production of highly densified single-phase bulk SBT by conventional sintering procedures is strongly compromised by stoichiometric changes due to bismuth loss. In this work, high-pressure sintering has been exploited as an alternative procedure to obtain SBT highly-densified single-phase compacts. Using toroidal-type high-pressure chambers, samples were produced by reaction sintering of BiTaO{sub 4} and SrCO{sub 3} powders, mixed in the stoichiometric ratio corresponding to SrBi{sub 2}Ta{sub 2}O{sub 9}, at pressures of 2.5 GPa and 7.7 GPa, and temperatures up to 1250°C, during 10 min. X-ray diffraction and scanning electron microscopy associated to energy-dispersive X-ray spectroscopy were used to follow the phase composition and the microstructure evolution as a function of the processing conditions. A single-phase SBT compact, with a relative density of 93% and a homogeneous microstructure, was produced by sintering at 2.5 GPa/900°C [2]. References: [1] K. Panda, J. Mater. Sci. 44, 5049-5062 (2009). [2] Ricson R.Souza, Rejane K. Kirchner, Jose R. Jurado, Altair S. Pereira, Vania C. Sousa. Journal of Solid State Chemistry 233, 259-268 (2016). (author)

The Incidence of Complications in Single-stage Endoscopic Stone Removal for Patients with Common Bile Duct Stones: A Propensity Score Analysis.

Science.gov (United States)

Saito, Hirokazu; Kadono, Yoshihiro; Kamikawa, Kentaro; Urata, Atsushi; Imamura, Haruo; Matsushita, Ikuo; Kakuma, Tatsuyuki; Tada, Shuji

2018-02-15

Objective Single-stage endoscopic stone removal for choledocholithiasis is an advantageous approach because it is associated with a shorter hospital stay; however, few studies have reported the incidence of complications related to this procedure in detail. The aim of this study was to examine the incidence of complications and efficacy of this procedure. Methods This retrospective study investigated the incidence of complications in 345 patients with naive papilla who underwent therapeutic endoscopic retrograde cholangiopancreatography (ERCP) for choledocholithiasis at three institutions between April 2014 and March 2016 by a propensity score analysis. The efficacy of single-stage endoscopic stone removal was assessed based on a hospital stay of within 7 days and the number of ERCP attempts. Results Among 114 patients who underwent single-stage endoscopic stone removal, 15 patients (13.2%) experienced complications. Among the remaining 231 patients in the two-stage endoscopic stone removal group, complications were observed in 17 patients (7.4%). The propensity score analysis, which was adjusted for confounding factors, revealed that single-stage endoscopic stone removal was not a significant risk factor for complications (p=0.52). In patients in whom >10 min was required for deep cannulation, single-stage endoscopic stone removal was not a significant risk factor for complications in the propensity score analysis (p=0.37). In the single-stage group, the proportion of patients with a hospital stay of within 7 days was significantly higher and the number of ERCP attempts was significantly lower in comparison to the two-stage group (p <0.0001 and <0.0001, respectively). Conclusion Single-stage endoscopic stone removal did not increase the incidence of complications associated with ERCP and was effective for reducing the hospital stay and the number of ERCP attempts.

A tetrad of bicuspid aortic valve association: A single-stage repair

Science.gov (United States)

Barik, Ramachandra; Patnaik, A. N.; Mishra, Ramesh C.; Kumari, N. Rama; Gulati, A. S.

2012-01-01

We report a 27 years old male who presented with a combination of both congenital and acquired cardiac defects. This syndrome complex includes congenital bicuspid aortic valve, Seller's grade II aortic regurgitation, juxta- subclavian coarctation, stenosis of ostium of left subclavian artery and ruptured sinus of Valsalva aneurysm without any evidence of infective endocarditis. This type of constellation is extremely rare. Neither coarctation of aorta with left subclavian artery stenosis nor the rupture of sinus Valsalva had a favorable pathology for percutaneus intervention. Taking account into morbidity associated with repeated surgery and anesthesia patient underwent a single stage surgical repair of both the defects by two surgical incisions. The approaches include median sternotomy for rupture of sinus of Valsalva and lateral thoracotomy for coarctation with left subclavian artery stenosis. The surgery was uneventful. After three months follow up echocardiography showed mild residual gradient across the repaired coarctation segment, mild aortic regurgitation and no residual left to right shunt. This patient is under follow up. This is an extremely rare case of single stage successful repair of coarctation and rupture of sinus of Valsalva associated with congenital bicuspid aortic valve. PMID:22629035

Large Conization and Laparoendoscopic Single-Port Pelvic Lymphadenectomy in Early-Stage Cervical Cancer for Fertility Preservation

Directory of Open Access Journals (Sweden)

Polat Dursun

2013-01-01

Full Text Available Fertility preservation in early-stage cervical cancer is a hot topic in gynecologic oncology. Although radical vaginal trachelectomy (RVT is suggested as a fertility preserving approach, there are some serious concerns like cervical stenosis, second trimester loss, preterm delivery in survivors, and lack of residual tumor in the majority of the surgical specimens. Therefore, less radical surgical operations have been proposed in early-stage cervical carcinomas. On the other hand, single-incision laparoscopic surgery (SILS is an evolving endoscopic approach for minimal access surgery. In this report, we present a case with early-stage cervical cancer who wishes to preserve fertility. We successfully performed single-port pelvic lymphadenectomy and large conization to preserve fertility potential of the patient. We think that combination of less radical approach like conization and single-port pelvic lymphadenectomy might be less minimally invasive and is still an effective surgical approach in well-selected cases with cervical carcinomas. Incorporation of single-port laparoscopy into the minimally invasive fertility sparing management of the cervical cancer will improve patients outcome with less complications and better cosmesis. Further studies are needed to reach a clear conclusion.

Compact-immersed-tube bath heating for anodizing aluminum sections; Le chauffage de bains par tubes immerges compacts pour l`anodisation de profiles aluminium

Energy Technology Data Exchange (ETDEWEB)

Bouillet, B. [Societe Alusuisse (France); Lhomme, P.J. [Gaz de France (GDF), 75 - Paris (France)

1996-12-31

The compact-immersed-tube system is composed of a burner, a combustor (where natural gas is burned) and a heat exchanger tube (where combustion heat is released to the surrounding bath); its compact configuration is designed for a direct implementation in an industrial process vessel. Natural gas is thus directly used at the utilization location, without any vapour stage and distribution heat losses. Temperature regulation, efficiency, corrosion issues and power requirements are discussed. An application example with the bath heating for aluminum anodization, is presented: energy savings and payback periods are discussed

Compactly supported frames for decomposition spaces

DEFF Research Database (Denmark)

Nielsen, Morten; Rasmussen, Kenneth Niemann

2012-01-01

In this article we study a construction of compactly supported frame expansions for decomposition spaces of Triebel-Lizorkin type and for the associated modulation spaces. This is done by showing that finite linear combinations of shifts and dilates of a single function with sufficient decay in b...

Porewater chemistry in compacted bentonite

Energy Technology Data Exchange (ETDEWEB)

Muurinen, A.; Lehikoinen, J. [VTT Chemical Technology, Espoo (Finland)

1999-03-01

In this study, the porewater chemistry in compacted bentonite, considered as an engineered barrier in the repository of spent fuel, has been studied in interaction experiments. Many parameters, like the composition and density of bentonite, composition of the solution, bentonite-to-water ratio (B/W), surrounding conditions and experimental time have been varied in the experiments. At the end of the interaction the equilibrating solution, the porewaters squeezed out of the bentonite samples, and bentonites themselves were analyzed to give information for the interpretation and modelling of the interaction. Equilibrium modelling was performed with the HYDRAQL/CE computer code 33 refs.

Fuel system for diesel engine with multi-stage heated

Science.gov (United States)

Ryzhov, Yu N.; Kuznetsov, Yu A.; Kolomeichenko, A. V.; Kuznetsov, I. S.; Solovyev, R. Yu; Sharifullin, S. N.

2017-09-01

The article describes a fuel system of a diesel engine with a construction tractor multistage heating, allowing the use of pure rapeseed oil as a diesel engine fuel. The paper identified the kinematic viscosity depending on the temperature and composition of the mixed fuel, supplemented by the existing recommendations on the use of mixed fuels based on vegetable oils and developed the device allowing use as fuel for diesel engines of biofuels based on vegetable oils.

Mixed Uranium/Refractory Metal Carbide Fuels for High Performance Nuclear Reactors

International Nuclear Information System (INIS)

Knight, Travis; Anghaie, Samim

2002-01-01

Single phase, solid-solution mixed uranium/refractory metal carbides have been proposed as an advanced nuclear fuel for advanced, high-performance reactors. Earlier studies of mixed carbides focused on uranium and either thorium or plutonium as a fuel for fast breeder reactors enabling shorter doubling owing to the greater fissile atom density. However, the mixed uranium/refractory carbides such as (U, Zr, Nb)C have a lower uranium densities but hold significant promise because of their ultra-high melting points (typically greater than 3700 K), improved material compatibility, and high thermal conductivity approaching that of the metal. Various compositions of (U, Zr, Nb)C were processed with 5% and 10% metal mole fraction of uranium. Stoichiometric samples were processed from the constituent carbide powders, while hypo-stoichiometric samples with carbon-to-metal (C/M) ratios of 0.92 were processed from uranium hydride, graphite, and constituent refractory carbide powders. Processing techniques of cold uniaxial pressing, dynamic magnetic compaction, sintering, and hot pressing were investigated to optimize the processing parameters necessary to produce high density (low porosity), single phase, solid-solution mixed carbide nuclear fuels for testing. This investigation was undertaken to evaluate and characterize the performance of these mixed uranium/refractory metal carbides for high performance, ultra-safe nuclear reactor applications. (authors)

Procedures and apparatus for measuring diffusion and distribution coefficients in compacted clays

Energy Technology Data Exchange (ETDEWEB)

Hume, H B

1993-12-01

Diffusion and distribution coefficients are needed to assess the migration of radionuclides through the compacted clay-based buffer and backfill materials proposed for use in a nuclear fuel waste disposal vault. This report describes the techniques used to measure these coefficients. Both steady-state and transient diffusion experiments are discussed. The procedures used to prepare the clay plug, assemble the cell, conduct the experiment and calculate the results are described. In addition, methods for obtaining distribution coefficients for radionuclides on both loose and compacted clays are discussed. (author). 18 refs., 3 tabs., 16 figs.

Procedures and apparatus for measuring diffusion and distribution coefficients in compacted clays

International Nuclear Information System (INIS)

Hume, H.B.

1993-12-01

Diffusion and distribution coefficients are needed to assess the migration of radionuclides through the compacted clay-based buffer and backfill materials proposed for use in a nuclear fuel waste disposal vault. This report describes the techniques used to measure these coefficients. Both steady-state and transient diffusion experiments are discussed. The procedures used to prepare the clay plug, assemble the cell, conduct the experiment and calculate the results are described. In addition, methods for obtaining distribution coefficients for radionuclides on both loose and compacted clays are discussed. (author). 18 refs., 3 tabs., 16 figs

Practical consideration of nuclear fuel spiking for proliferation deterrence

International Nuclear Information System (INIS)

Selle, J.E.; Angelini, P.; Rainey, R.H.; Federer, J.I.; Olsen, A.R.

1978-10-01

The use of a gamma active radionuclide with nuclear fuel has been proposed as a way to inhibit unauthorized diversion of the fuel and thus provide proliferation deterrence. The purpose of this report is to examine some of the practical aspects of incorporating spikants into nuclear fuel in an attempt to identify any adverse consequences of their use. Selection of potential spikants was made by the application of some somewhat arbitrary radiation criteria to 64 candidate spikants followed by an analysis of the chemical and physical state of each potential spikant. As a result of this analysis the list of candidates was narrowed to 60 Co, 106 Ru, and 144 Ce. Following this, we investigated the practical aspects of the use of these three spikants in nuclear fuel. Among the subjects considered are: dose rates available from fuel elements, fission product buildup, chemical behavior of spikants during reproecssing, and possible effects of spikants on refabrication and on the fuel properties. No single radionuclide was found to be preferred in all stages of reprocessing and refabriaction. In order to provide deterrence in all stages of reprocessing and refabrication, a duplex spiking process appears necessary, in which two different spikants, 106 Ru and 60 Co, are used in different portions of reprocessing. The use of nominal amounts of ruthenium or cobalt as spikants is not expected to adversely affect fuel performance

HRB-22 capsule irradiation test for HTGR fuel. JAERI/USDOE collaborative irradiation test

Energy Technology Data Exchange (ETDEWEB)

Minato, Kazuo; Sawa, Kazuhiro; Fukuda, Kousaku [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; and others

1998-03-01

As a JAERI/USDOE collaborative irradiation test for high-temperature gas-cooled reactor fuel, JAERI fuel compacts were irradiated in the HRB-22 irradiation capsule in the High Flux Isotope Reactor at the Oak Ridge National Laboratory (ORNL). Postirradiation examinations also were performed at ORNL. This report describes 1) the preirradiation characterization of the irradiation samples of annular-shaped fuel compacts containing the Triso-coated fuel particles, 2) the irradiation conditions and fission gas releases during the irradiation to measure the performance of the coated particle fuel, 3) the postirradiation examinations of the disassembled capsule involving visual inspection, metrology, ceramography and gamma-ray spectrometry of the samples, and 4) the accident condition tests on the irradiated fuels at 1600 to 1800degC to obtain information about fuel performance and fission product release behavior under accident conditions. (author)

Studies on the sintering of copper powder compacts

International Nuclear Information System (INIS)

Elmasry, M.A.A.; Abadir, M.F.; Mahdy, A.N.; Elkinawy, W.S.

1995-01-01

Solid state sintering behavior of cylindrical compacts, (1 cm diameter and 1 cm height), made of copper powder was studied within a range of compacting pressure of 75 up to 300 MPa, sintering temperature of 600 up to to 900 degree C, and sintering time of 5 up to 60 min in a reducing atmosphere composed of H2 and N 2 gases with a volumetric ratio 3:1. The green and the sintered densities were found to to increase with the compacting pressure. Higher sintering temperature, and time favour increased sintered density. probable mechanisms during the initial stage of sintering were disclosed. It was found that low pressures cause dilation of closed pores, and vice versa. At low pressures and temperatures the surface diffusion mechanism is favoured, While high temperatures favour lattice diffusion mechanism. at high pressures, the lattice diffusion mechanism is suppressed while surface diffusion predominates. Density and hence shrinkage were also found to increase with the increase of sintering time, While its rate increases with the increase of sintering temperature. the influence of sintering conditions on the hardness of the compacts was studied. An increase in hardness, When higher compacting pressures and higher sintering temperatures were adopted, has bee obtained. 11 figs

Determining the axial power profile of partly flooded fuel in a compact core assembled in reactor LR-0

International Nuclear Information System (INIS)

Košťál, Michal; Švadlenková, Marie; Baroň, Petr; Rypar, Vojtěch; Milčák, Ján

2016-01-01

Highlights: • Fission density in partly flooded compact core. • Calculation of fission density axial profile. • Significant calculational under prediction of experimental axial profile. - Abstract: Measurement and calculation of the axial power profile near the boundary of a moderated and non-moderated core is used to analyze the suitability of the neutron-physical process description, mainly the angular cross-section of a water-moderated uranium system. This is also an important issue because it affects the radiation situation above the partly flooded core of a water-moderated reactor. Axial power profiles of various fuel pins irradiated on reactor LR-0 were measured and the results were compared with MCNP6 code calculations using the ENDF/B-VII.0 nuclear data library. The calculated power profile in positions above the moderator level significantly underestimates experimental results. This might be caused by an improper description of the angular distribution of scattered neutrons in a water-moderated uranium system.

The compaction and sintering of UO_2-Zr cermet pellets

International Nuclear Information System (INIS)

Tri Yulianto; Meniek Rachmawati; Etty Mutiara

2013-01-01

An innovative fuel pellet of UO_2-Zr cermet has been developed to improve thermal conductivity of UO_2 pellet by adding small amount Zr metal in to UO_2 matrix below 10 % weight. Zirconium powder will serve for the creation of bridges or web structure during compaction and will effectively reduce contact between of UO_2 particles. Based on the theory of phase equilibrium of metals-metal oxides-ceramic, this fabrication technique may produce UO_2 pellets containing continuous metal channel on the grain boundary of UO_2 through sintering in a reduction atmosphere. The fabrication was done by varying process parameters of mixing and compaction. Characterisation of UO_2-Zr cermet pellet involved visual test, dimensional and density measurement, and ceramography test. This advanced cermet fabrication technology may address common issue with cermet fuels such as microstructure with continuous metal channel structure in the UO_2 matrix, which is more effectively than the commonly accepted microstructure involving fraction of UO_2 pellet by standard fabrication route. (author)

Analysis of laboratory compaction methods of roller compacted concrete

Science.gov (United States)

Trtík, Tomáš; Chylík, Roman; Bílý, Petr; Fládr, Josef

2017-09-01

Roller-Compacted Concrete (RCC) is an ordinary concrete poured and compacted with machines typically used for laying of asphalt road layers. One of the problems connected with this technology is preparation of representative samples in the laboratory. The aim of this work was to analyse two methods of preparation of RCC laboratory samples with bulk density as the comparative parameter. The first method used dynamic compaction by pneumatic hammer. The second method of compaction had a static character. The specimens were loaded by precisely defined force in laboratory loading machine to create the same conditions as during static rolling (in the Czech Republic, only static rolling is commonly used). Bulk densities obtained by the two compaction methods were compared with core drills extracted from real RCC structure. The results have shown that the samples produced by pneumatic hammer tend to overestimate the bulk density of the material. For both compaction methods, immediate bearing index test was performed to verify the quality of compaction. A fundamental difference between static and dynamic compaction was identified. In static compaction, initial resistance to penetration of the mandrel was higher, after exceeding certain limit the resistance was constant. This means that the samples were well compacted just on the surface. Specimens made by pneumatic hammer actively resisted throughout the test, the whole volume was uniformly compacted.

Compact source of narrow-band counterpropagating polarization-entangled photon pairs using a single dual-periodically-poled crystal

International Nuclear Information System (INIS)

Gong, Yan-Xiao; Xie, Zhen-Da; Xu, Ping; Zhu, Shi-Ning; Yu, Xiao-Qiang; Xue, Peng

2011-01-01

We propose a scheme for the generation of counterpropagating polarization-entangled photon pairs from a dual-periodically-poled crystal. Compared with the usual forward-wave-type source, this source, in the backward-wave way, has a much narrower bandwidth. With a 2-cm-long bulk crystal, the bandwidths of the example sources are estimated to be 3.6 GHz, and the spectral brightnesses are more than 100 pairs/(s GHz mW). Two concurrent quasi-phase-matched spontaneous parametric down-conversion processes in a single crystal enable our source to be compact and stable. This scheme does not rely on any state projection and applies to both degenerate and nondegenerate cases, facilitating applications of the entangled photons.

Grid Integration of Single Stage Solar PV System using Three-level Voltage Source Converter

Science.gov (United States)

Hussain, Ikhlaq; Kandpal, Maulik; Singh, Bhim

2016-08-01

This paper presents a single stage solar PV (photovoltaic) grid integrated power generating system using a three level voltage source converter (VSC) operating at low switching frequency of 900 Hz with robust synchronizing phase locked loop (RS-PLL) based control algorithm. To track the maximum power from solar PV array, an incremental conductance algorithm is used and this maximum power is fed to the grid via three-level VSC. The use of single stage system with three level VSC offers the advantage of low switching losses and the operation at high voltages and high power which results in enhancement of power quality in the proposed system. Simulated results validate the design and control algorithm under steady state and dynamic conditions.

Hot-stage microscopy for determination of API fragmentation: comparison with other methods.

Science.gov (United States)

Šimek, Michal; Grünwaldová, Veronika; Kratochvíl, Bohumil

2016-08-01

Although the fragmentation of the active pharmaceutical ingredient (API) is a phenomenon that is mentioned in many literature sources, no well-suited analytical tools for its investigation are currently known. We used the hot-stage microscopy method, already presented in our previous work, and studied the real fragmentation of the tadalafil particles in model tablets which were prepared under different compaction pressures. The morphology, spectral imaging and evaluation of plastic and elastic energies were also analyzed to support the hot-stage method. The prepared blend of tadalafil and excipients was compacted under a several forces from 5 to 35 kN to reveal the trend of fragmentation. The exact fragmentation of tadalafil with increased compaction pressure was revealed by the hot-stage microscopic method and it was in good agreement with plastic and elastic energies. Conversely, spectral imaging, which is being used for this analysis, was considered to be inaccurate methodology as mainly agglomerates, not individual particles, were measured. The availability of the hot-stage microscopic method equips pharmaceutical scientists with an in vitro assessment technique that will more reliably determine the fragmentation of the API in finished tablets and the behavior of the particles when compacted.

Materials needs for compact fusion reactors

International Nuclear Information System (INIS)

Krakowski, R.A.

1983-01-01

The economic prospects for magnetic fusion energy can be dramatically improved if for the same total power output the fusion neutron first-wall (FW) loading and the system power density can be increased by factors of 3 to 5 and 10 to 30, respectively. A number of compact fusion reactor embodiments have been proposed, all of which would operate with increased FW loadings, would use thin (0.5 to 0.6 m) blankets, and would confine quasi-steady-state plasma with resistive, water-cooled copper or aluminum coils. Increased system power density (5 to 15 MWt/m 3 versus 0.3 to 0.5 MW/m 3 ), considerably reduced physical size of the fusion power core (FPC), and appreciably reduced economic leverage exerted by the FPC and associated physics result. The unique materials requirements anticipated for these compact reactors are outlined against the well documented backdrop provided by similar needs for the mainline approaches. Surprisingly, no single materials need that is unique to the compact systems is identified; crucial uncertainties for the compact approaches must also be addressed by the mainline approaches, particularly for in-vacuum components (FWs, limiters, divertors, etc.)

A design study of high breeding ratio sodium cooled metal fuel core without blanket fuels

International Nuclear Information System (INIS)

Kobayashi, Noboru; Ogawa, Takashi; Ohki, Shigeo; Mizuno, Tomoyasu; Ogata, Takanari

2009-01-01

The metal fuel core is superior to the mixed oxide fuel core because of its high breeding ratio and compact core size resulting from hard neutron spectrum and high heavy metal densities. Utilizing these characteristics, a conceptual design for a high breeding ratio was performed without blanket fuels. The design conditions were set so a sodium void worth of less than 8 $, a core height of less than 150 cm, the maximum cladding temperature of 650degC, and the maximum fuel pin bundle pressure drop of 0.4 MPa. The breeding ratio of the resultant core was 1.34 with 6wt% zirconium content fuel. Applying 3wt% zirconium content fuel enhanced the breeding ratio up to 1.40. (author)

Two stage bioethanol refining with multi litre stacked microbial fuel cell and microbial electrolysis cell.

Science.gov (United States)

Sugnaux, Marc; Happe, Manuel; Cachelin, Christian Pierre; Gloriod, Olivier; Huguenin, Gérald; Blatter, Maxime; Fischer, Fabian

2016-12-01

Ethanol, electricity, hydrogen and methane were produced in a two stage bioethanol refinery setup based on a 10L microbial fuel cell (MFC) and a 33L microbial electrolysis cell (MEC). The MFC was a triple stack for ethanol and electricity co-generation. The stack configuration produced more ethanol with faster glucose consumption the higher the stack potential. Under electrolytic conditions ethanol productivity outperformed standard conditions and reached 96.3% of the theoretically best case. At lower external loads currents and working potentials oscillated in a self-synchronized manner over all three MFC units in the stack. In the second refining stage, fermentation waste was converted into methane, using the scale up MEC stack. The bioelectric methanisation reached 91% efficiency at room temperature with an applied voltage of 1.5V using nickel cathodes. The two stage bioethanol refining process employing bioelectrochemical reactors produces more energy vectors than is possible with today's ethanol distilleries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Status of the variable momentum compaction storage ring experiment in SPEAR

International Nuclear Information System (INIS)

Tran, P.; Amiry, A.; Pellegrini, C.

1993-01-01

Variable momentum compaction lattices have been proposed for electron-positron colliders and synchrotron radiation sources to control synchrotron tune and bunch length. To address questions of single particle stability limits, a study has been initiated to change the SPEAR lattice into a variable momentum compaction configuration for experimental investigation of the beam dynamics. In this paper, we describe a model-based method used to transform SPEAR from the injection lattice to the low momentum compaction configuration. Experimental observations of the process are reviewed

Attainability and minimum energy of single-stage membrane and membrane/distillation hybrid processes

KAUST Repository

Alshehri, Ali

2014-12-01

As an energy-efficient separation method, membrane technology has attracted more and more attentions in many challenging separation processes. The attainability and the energy consumption of a membrane process are the two basic fundamental questions that need to be answered. This report aims to use process simulations to find: (1) at what conditions a single-stage membrane process can meet the separation task that is defined by product purity and recovery ratio and (2) what are the most important parameters that determine the energy consumption. To perform a certain separation task, it was found that both membrane selectivity and pressure ratio exhibit a minimum value that is defined only by product purity and recovery ratio. The membrane/distillation hybrid system was used to study the energy consumption. A shortcut method was developed to calculate the minimum practical separation energy (MPSE) of the membrane process and the distillation process. It was found that the MPSE of the hybrid system is only determined by the membrane selectivity and the applied transmembrane pressure ratio in three stages. At the first stage when selectivity is low, the membrane process is not competitive to the distillation process. Adding a membrane unit to a distillation tower will not help in reducing energy. At the second medium selectivity stage, the membrane/distillation hybrid system can help reduce the energy consumption, and the higher the membrane selectivity, the lower is the energy. The energy conservation is further improved as pressure ratio increases. At the third stage when both selectivity and pressure ratio are high, the hybrid system will change to a single-stage membrane unit and this change will cause significant reduction in energy consumption. The energy at this stage keeps decreasing with selectivity at slow rate, but slightly increases with pressure ratio. Overall, the higher the membrane selectivity, the more the energy is saved. Therefore, the two

Development of a hybrid mode linear transformer driver stage

Science.gov (United States)

Zhang, Le; Wang, Meng; Zhou, Liangji; Tian, Qing; Guo, Fan; Wang, Lingyun; Qing, Yanling; Zhao, Yue; Dai, Yingmin; Han, Wenhui; Chen, Lin; Xie, Weiping

2018-02-01

At present, the mainstream technologies of primary power sources of large pulse power devices adopt Marx or linear transformer driver (LTD) designs. Based on the analysis of the characteristics of these two types of circuit topologies, the concept of a hybrid mode LTD stage based on Marx branches is proposed. The analysis shows that the hybrid mode LTD stage can realize the following goals: (a) to reduce the energy and power handled by the basic components (switch and capacitor) to lengthen their lifetime; (b) to reduce the requirements of the multipath synchronous trigger system; and (c) to improve the maintainability of the LTD stage by using independent Marx generators instead of "traditional LTD bricks." To verify the technique, a hybrid mode LTD stage consisting of 50 branches (four-stage compact Marx generators) was designed, manufactured and tested. The stage has a radius of about 3.3 m and a height of 0.6 m. The single Marx circuit's load current is about 21 kA, with a rise time of ˜90 ns (10%-90%), under the conditions of capacitors charged to ±40 kV and a 6.9 Ω matched load. The whole stage's load current is ˜1 MA , with a rise time of ˜112 ns (10%-90%), when the capacitors are charged to ±45 kV and the matched load is 0.14 Ω .

Spent nuclear fuel project product specification

International Nuclear Information System (INIS)

Pajunen, A.L.

1998-01-01

Product specifications are limits and controls established for each significant parameter that potentially affects safety and/or quality of the Spent Nuclear Fuel (SNF) packaged for transport to dry storage. The product specifications in this document cover the spent fuel packaged in MultiCanister Overpacks (MCOs) to be transported throughout the SNF Project. The SNF includes N Reactor fuel and single-pass reactor fuel. The FRS removes the SNF from the storage canisters, cleans it, and places it into baskets. The MCO loading system places the baskets into MCO/Cask assembly packages. These packages are then transferred to the Cold Vacuum Drying (CVD) Facility. After drying at the CVD Facility, the MCO cask packages are transferred to the Canister Storage Building (CSB), where the MCOs are removed from the casks, staged, inspected, sealed (by welding), and stored until a suitable permanent disposal option is implemented. The key criteria necessary to achieve these goals are documented in this specification

Fabrication of Fast Reactor Fuel Pins for Test Irradiations

Energy Technology Data Exchange (ETDEWEB)

Karsten, G. [Institute for Applied Reactor Physics, Kernforschungszentrum Karlsruhe, Karlsruhe, Federal Republic of Germany (Germany); Dippel, T. [Institute for Radiochemistry, Kernforschungszentrum Karlsruhe, Karlsruhe, Federal Republic of Germany (Germany); Laue, H. J. [Institute for Applied Reactor Physics, Kernforschungszentrum Karlsruhe, Karlsruhe, Federal Republic of Germany (Germany)

1967-09-15

An extended irradiation programme is being carried out for the fuel element development of the Karlsruhe fast breeder project. A very important task within the programme is the testing of plutonium-containing fuel pins in a fast-reactor environment. This paper deals with fabrication of such pins by our laboratories at Karlsruhe. For the fast reactor test positions at present envisaged a fuel with 15% plutonium and the uranium fully enriched is appropriate. Hie mixed oxide is both pelletized and vibro-compacted with smeared densities between 80 and 88% theoretical. The pin design is, for example, such that there are two gas plena at the top and bottom, and one blanket above the fuel with the fuel zone fitting to the test reactor core length. The specifications both for fuel and cladding have been adapted to the special purpose of a fast-breeder reactor - the outer dimensions, the choice of cladding and fuel types, the data used and the kind of tests outline the targets of the development. The fuel fabrication is described in detail, and also the powder line used for vibro-compaction. The source materials for the fuel are oxalate PuO{sub 2} and UO{sub 2} from the UF{sub 6} process. The special problems of mechanical mixing and of plutonium homogeneity have been studied. The development of the sintering technique and grain characteristics for vibratory compactive fuel had to overcome serious problems in order to reach 82-83% theoretical. The performance of the pin fabrication needed a major effort in welding, manufacturing of fits and decontamination of the pin surfaces. This was a stimulation for the development of some very subtle control techniques, for example taking clear X-ray photographs and the tube testing. In general the selection of tests was a special task of the production routine. In conclusion the fabrication of the pins resulted in valuable experiences for the further development of fast reactor fuel elements. (author)

Fuel-Cell Structure Prevents Membrane Drying

Science.gov (United States)

Mcelroy, J.

1986-01-01

Embossed plates direct flows of reactants and coolant. Membrane-type fuel-cell battery has improved reactant flow and heat removal. Compact, lightweight battery produces high current and power without drying of membranes.

A survivability model for ejection of green compacts in powder metallurgy technology

Directory of Open Access Journals (Sweden)

Payman Ahi

2012-01-01

Full Text Available Reliability and quality assurance have become major considerations in the design and manufacture of today’s parts and products. Survivability of green compact using powder metallurgy technology is considered as one of the major quality attributes in manufacturing systems today. During powder metallurgy (PM production, the compaction conditions and behavior of the metal powder dictate the stress and density distribution in the green compact prior to sintering. These parameters greatly influence the mechanical properties and overall strength of the final component. In order to improve these properties, higher compaction pressures are usually employed, which make unloading and ejection of green compacts more challenging, especially for the powder-compacted parts with relatively complicated shapes. This study looked at a mathematical survivability model concerning green compact characteristics in PM technology and the stress-strength failure model in reliability engineering. This model depicts the relationship between mechanical loads (stress during ejection, experimentally determined green strength and survivability of green compact. The resulting survivability is the probability that a green compact survives during and after ejection. This survivability model can be used as an efficient tool for selecting the appropriate parameters for the process planning stage in PM technology. A case study is presented here in order to demonstrate the application of the proposed survivability model.

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-09-01

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

Fission product monitoring of TRISO coated fuel for the advanced gas reactor-1 experiment

International Nuclear Information System (INIS)

Scates, Dawn M.; Hartwell, John K.; Walter, John B.; Drigert, Mark W.; Harp, Jason M.

2010-01-01

The US Department of Energy has embarked on a series of tests of TRISO coated particle reactor fuel intended for use in the Very High Temperature Reactor (VHTR) as part of the Advanced Gas Reactor (AGR) program. The AGR-1 TRISO fuel experiment, currently underway, is the first in a series of eight fuel tests planned for irradiation in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The AGR-1 experiment reached a peak compact averaged burnup of 9% FIMA with no known TRISO fuel particle failures in March 2008. The burnup goal for the majority of the fuel compacts is to have a compact averaged burnup greater than 18% FIMA and a minimum compact averaged burnup of 14% FIMA. At the INL the TRISO fuel in the AGR-1 experiment is closely monitored while it is being irradiated in the ATR. The effluent monitoring system used for the AGR-1 fuel is the Fission Product Monitoring System (FPMS). The FPMS is a valuable tool that provides near real-time data indicative of the AGR-1 test fuel performance and incorporates both high-purity germanium (HPGe) gamma-ray spectrometers and sodium iodide [NaI(Tl)] scintillation detector-based gross radiation monitors. To quantify the fuel performance, release-to-birth ratios (R/B's) of radioactive fission gases are computed. The gamma-ray spectra acquired by the AGR-1 FPMS are analyzed and used to determine the released activities of specific fission gases, while a dedicated detector provides near-real time count rate information. Isotopic build up and depletion calculations provide the associated isotopic birth rates. This paper highlights the features of the FPMS, encompassing the equipment, methods and measures that enable the calculation of the release-to-birth ratios. Some preliminary results from the AGR-1 experiment are also presented.

Fuels from agriculture. Report stage 4 1981-1983

Energy Technology Data Exchange (ETDEWEB)

Renborg, U.

1984-01-01

The aim of the project is to identify possible fuel crops in agriculture and which energy carriers can be produced from these raw products. Surveys are made of the yields of various energy crops under different production conditions. Studies are also made of systems for cultivation, harvesting, handling and processing of the raw products. The chemical properties of the fuel crops with regard to different ranges of use are also analysed. Studies have also been made of the economic conditions concerning energy crops from the perspectives of the user, the grower and society. Different environmental consequences of growing and using energy crops are studied. The studies are mainly concentrated on the following crops: grain and sugar-rich root crops for production of ethanol; oilseed crops for production of vegetable oil; straw, energy grass and energy forestry (wood from shortrotation forests) to be used as solid fuels; and possibilities of producing biogas from crops such as lucerne, jerusalem artichoke, etc., with high yields of biomass are being tested. The economic analyses show that solid fuel from agriculture is capable of competing with fuel oil in heating plants with an effect of 0.2-1.0 MW. As regards cost, straw is also capable of competing with other kinds of fuel oils, forest fuels and peat. If we consider prevailing taxation conditions, a competetive alternative might be a restricted admixture of ethanol as a means of increasing the octane rating in petrol. However, this is under the condition that the by-products are fully utilized and can be marketed at the current market prices of protein feeds. Under conditions prevailing today, vegetable oil cannot compete with diesel oil.

Temperature-phased anaerobic digestion of food waste: A comparison with single-stage digestions based on performance and energy balance.

Science.gov (United States)

Xiao, Benyi; Qin, Yu; Zhang, Wenzhe; Wu, Jing; Qiang, Hong; Liu, Junxin; Li, Yu-You

2018-02-01

The temperature-phased anaerobic digestion (TPAD) of food waste was studied for the purpose of comparing with single-stage mesophilic and thermophilic anaerobic digestion. The biogas and methane yields in the TPAD during the steady period were 0.759 ± 0.115 L/g added VS and 0.454 ± 0.201 L/g added VS, which were lower than those in the two single-stage anaerobic digestion. The improper sludge retention time may be the reason for the lower biogas and methane production in TPAD. The removal of volatile solids in the TPAD was 78.55 ± 4.59% and the lowest among the three anaerobic digestion processes. The reaction ratios of the four anaerobic digestion steps in the TPAD were all lower than those in the two single-stage anaerobic digestion. The energy conversion efficiency of the degraded substrate in the TPAD was similar with those in single-stage mesophilic and thermophilic anaerobic digestion systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydrodeoxygenation of oils from cellulose in single and two-stage hydropyrolysis

Energy Technology Data Exchange (ETDEWEB)

Rocha, J.D.; Snape, C.E. [Strathclyde Univ., Glasgow (United Kingdom); Luengo, C.A. [Universidade Estadual de Campinas, SP (Brazil). Dept. de Fisica Aplicada

1996-09-01

To investigate the removal of oxygen (hydrodeoxygenation) during the hydropyrolysis of cellulose, single and two-stage experiments on pure cellulose have been carried out using hydrogen pressures up to 10 MPa and temperatures over the range 300-520{sup o}C. Carbon, oxygen and aromaticity balances have been determined from the product yields and compositions. For the two-stage tests, the primary oils were passed through a bed of commercial Ni/Mo {gamma}-alumina-supported catalyst (Criterion 424, presulphided) at 400{sup o}C. Raising the hydrogen pressure from atmospheric to 10 MPa increased the carbon conversion by 10 mole % which was roughly equally divided between the oil and hydrocarbon gases. The oxygen content of the primary oil was reduced by over 10% to below 20% w/w. The addition of a dispersed iron sulphide catalyst further increased the oil yield at 10 MPa and reduces the oxygen content of the oil by a further 10%. The effect of hydrogen pressure on oil yields was most pronounced at low flow rates where it is beneficial in helping to overcome diffusional resistances. Unlike the dispersed iron sulphide in the first stage, the use of the Ni-Mo catalyst in the second stage reduced both the oxygen content and aromaticity of the oils. (Author)

Evaluation of parameters effect on the maximum fuel temperature in the core thermal and hydraulic design of HTTR

International Nuclear Information System (INIS)

Fujimoto, Nozomu; Maruyama, Soh; Sudo, Yukio; Fujii, Sadao; Niguma, Yoshinori.

1988-10-01

This report presents the results of quantitative evaluation on the effects of the dominant parameters on the maximum fuel temperature in the core thermal hydraulic design of the High Temperature Engineering Test Reactor(HTTR) of 30 MW in thermal power, 950 deg C in reactor outlet coolant temperature and 40 kg/cm 2 G in coolant pressure. The dominant parameters investigated are 1) Gap conductance. 2) Effect of eccertricity of fuel compacts in graphite sleeve. 3) Effect of spacer ribs on heat transfer coefficients. 4) Contact probability of fuel compact and graphite sleeve. 5) Validity of uniform radial power density in the fuel compacts. 6) Effect of impurity gas on gap conductance. 7) Effect of FP gas on gap conductance. The effects of these items on the maximum fuel temperature were quantitalively identified as hot spot factors. A probability of the appearance of the maximum fuel temperature was also evaluated in this report. (author)

Mechanical behaviors of the dispersion nuclear fuel plates induced by fuel particle swelling and thermal effect II: Effects of variations of the fuel particle diameters

International Nuclear Information System (INIS)

Ding Shurong; Wang Qiming; Huo Yongzhong

2010-01-01

In order to predict the irradiation mechanical behaviors of plate-type dispersion nuclear fuel elements, the total burnup is divided into two stages: the initial stage and the increasing stage. At the initial stage, the thermal effects induced by the high temperature differences between the operation temperatures and the room temperature are mainly considered; and at the increasing stage, the intense mechanical interactions between the fuel particles and the matrix due to the irradiation swelling of fuel particles are focused on. The large-deformation thermo-elasto-plasticity finite element analysis is performed to evaluate the effects of particle diameters on the in-pile mechanical behaviors of fuel elements. The research results indicate that: (1) the maximum Mises stresses and equivalent plastic strains at the matrix increase with the fuel particle diameters; the effects of particle diameters on the maximum first principal stresses vary with burnup, and the considered case with the largest particle diameter holds the maximum values all along; (2) at the cladding near the interface between the fuel meat and the cladding, the Mises stresses and the first principal stresses undergo major changes with increasing burnup, and different variations exist for different particle diameter cases; (3) the maximum Mises stresses at the fuel particles rise with the particle diameters.

Post-irradiation examination of HTR-fuel at the Austrian Research Centre Seibersdorf Ltd

International Nuclear Information System (INIS)

Reitsamer, G.; Proksch, E.; Stolba, G.; Strigl, A.; Falta, G.; Zeger, J.

1985-01-01

Austrian R and D activities in the HTR-field reach back almost to the beginning of this advanced reactor line. For more than 20 years post-irradiation examination (PIE) of HTR-fuel has been performed at the laboratories of the Austrian Research Centre Seibersdorf Ltd. (OEFZS) (formerly OESGAE) and a high degree of qualification has been achieved in the course of that time. Most of the PIE-work has been carried out by international cooperation on contract basis with the OECD-DRAGON-project and with KFA-Juelich (FRG). There has also been some collaboration with GA (USA), Belgonucleaire and others in the past. HTR-fuel elements contain the fissile and fertile materials in form of coated particles (CPs) which are embedded in a graphite matrix. Because of this special design it has been necessary from the very beginning of the PIE work up to now to develop new methods (i.e. fuel element disintegration methods, chlorine gas leach, single particle examination techniques...) as well as to adapt and improve already existing methods (i.e. gamma spectrometry, mass-spectrometry, optical methods...). The main interests on PIE-work at Seibersdorf are concentrated on particle performance, fission product distribution and the 'free' Uranium content (contamination and broken particles) of the fuel elements (fuel spheres or cylindrical compacts). A short compilation of the applied methods and of available instrumental facilities is given as follows: deconsolidation of fuel elements; equipment for electrochemical deconsolidation; examinations and measurements of graphite and electrolyte samples; examination of coated particles; single particle examinations

Post-irradiation examination of HTR-fuel at the Austrian Research Centre Seibersdorf Ltd

Energy Technology Data Exchange (ETDEWEB)

Reitsamer, G; Proksch, E; Stolba, G; Strigl, A; Falta, G; Zeger, J [Department of Chemistry, Austrian Research Centre Seibersdorf Ltd., Seibersdorf (Austria)

1985-07-01

Austrian R and D activities in the HTR-field reach back almost to the beginning of this advanced reactor line. For more than 20 years post-irradiation examination (PIE) of HTR-fuel has been performed at the laboratories of the Austrian Research Centre Seibersdorf Ltd. (OEFZS) (formerly OESGAE) and a high degree of qualification has been achieved in the course of that time. Most of the PIE-work has been carried out by international cooperation on contract basis with the OECD-DRAGON-project and with KFA-Juelich (FRG). There has also been some collaboration with GA (USA), Belgonucleaire and others in the past. HTR-fuel elements contain the fissile and fertile materials in form of coated particles (CPs) which are embedded in a graphite matrix. Because of this special design it has been necessary from the very beginning of the PIE work up to now to develop new methods (i.e., fuel element disintegration methods, chlorine gas leach, single particle examination techniques...) as well as to adapt and improve already existing methods (i.e. gamma spectrometry, mass-spectrometry, optical methods...). The main interests on PIE-work at Seibersdorf are concentrated on particle performance, fission product distribution and the 'free' Uranium content (contamination and broken particles) of the fuel elements (fuel spheres or cylindrical compacts). A short compilation of the applied methods and of available instrumental facilities is given as follows: deconsolidation of fuel elements; equipment for electrochemical deconsolidation; examinations and measurements of graphite and electrolyte samples; examination of coated particles; single particle examinations.

Comparison of Material Behavior of Matrix Graphite for HTGR Fuel Elements upon Irradiation: A literature Survey

Energy Technology Data Exchange (ETDEWEB)

Lee, Young-Woo; Yeo, Seunghwan; Cho, Moon Sung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-05-15

The fuel elements for the HTGRs (i.e., spherical fuel element in pebble-bed type core design and fuel compact in prismatic core design) consists of coated fuel particles dispersed and bonded in a closely packed array within a carbonaceous matrix. This matrix is generally made by mixing fully graphitized natural and needle- or pitchcoke originated powders admixed with a binder material (pitch or phenolic resin), The resulting resinated graphite powder mixture, when compacted, may influence a number of material properties as well as its behavior under neutron irradiation during reactor operation. In the fabrication routes of these two different fuel element forms, different consolidation methods are employed; a quasi-isostatic pressing method is generally adopted to make pebbles while fuel compacts are fabricated by uni-axial pressing mode. The result showed that the hardness values obtained from the two directions showed an anisotropic behavior: The values obtained from the perpendicular section showed much higher micro hardness (176.6±10.5MPa in average) than from the parallel section ((125.6±MPa in average). This anisotropic behavior was concluded to be related to the microstructure of the matrix graphite. This may imply that the uni-axial pressing method to make compacts influence the microstructure of the matrix and hence the material properties of the matrix graphite.

Genomic Prediction of Single Crosses in the Early Stages of a Maize Hybrid Breeding Pipeline

Directory of Open Access Journals (Sweden)

Dnyaneshwar C. Kadam

2016-11-01

Full Text Available Prediction of single-cross performance has been a major goal of plant breeders since the beginning of hybrid breeding. Recently, genomic prediction has shown to be a promising approach, but only limited studies have examined the accuracy of predicting single-cross performance. Moreover, no studies have examined the potential of predicting single crosses among random inbreds derived from a series of biparental families, which resembles the structure of germplasm comprising the initial stages of a hybrid maize breeding pipeline. The main objectives of this study were to evaluate the potential of genomic prediction for identifying superior single crosses early in the hybrid breeding pipeline and optimize its application. To accomplish these objectives, we designed and analyzed a novel population of single crosses representing the Iowa Stiff Stalk synthetic/non-Stiff Stalk heterotic pattern commonly used in the development of North American commercial maize hybrids. The performance of single crosses was predicted using parental combining ability and covariance among single crosses. Prediction accuracies were estimated using cross-validation and ranged from 0.28 to 0.77 for grain yield, 0.53 to 0.91 for plant height, and 0.49 to 0.94 for staygreen, depending on the number of tested parents of the single cross and genomic prediction method used. The genomic estimated general and specific combining abilities showed an advantage over genomic covariances among single crosses when one or both parents of the single cross were untested. Overall, our results suggest that genomic prediction of single crosses in the early stages of a hybrid breeding pipeline holds great potential to redesign hybrid breeding and increase its efficiency.

Performance of the rebuilt SUERC single-stage accelerator mass spectrometer

Science.gov (United States)

Shanks, Richard P.; Ascough, Philippa L.; Dougans, Andrew; Gallacher, Paul; Gulliver, Pauline; Rood, Dylan H.; Xu, Sheng; Freeman, Stewart P. H. T.

2015-10-01

The SUERC bipolar single-stage accelerator mass spectrometer (SSAMS) has been dismantled and rebuilt to accommodate an additional rotatable pre-accelerator electrostatic spherical analyser (ESA) and a second ion source injector. This is for the attachment of an experimental positive-ion electron cyclotron resonance (ECR) ion source in addition to a Cs-sputter source. The ESA significantly suppresses oxygen interference to radiocarbon detection, and remaining measurement interference is now thought to be from 13C injected as 13CH molecule scattering off the plates of a second original pre-detector ESA.

High-pressure gas-breakthrough apparatus and a procedure for determining the gas-breakthrough pressure of compacted clay

International Nuclear Information System (INIS)

Hume, H.B.

1997-08-01

Gas may be produced in a nuclear fuel waste disposal vault. Given that the vault will be sealed with clay-based materials, the fate of the gas is uncertain. Therefore, an instrument was previously built to measure the pressure required to pass gas through compacted clay materials (a gas-breakthrough apparatus). However, the 10 MPa pressure limit of the apparatus was insufficient to test compacted buffer material at the density proposed in the Canadian concept for nuclear fuel waste disposal. Therefore, a high-pressure (50 Wa) gas-breakthrough apparatus was designed, constructed and installed. This report describes the components of the apparatus and the materials and procedures that are used for the gas-breakthrough tests. (author)

Finite Element Simulation of the Compaction and Springback of Alumix 321 PM Alloy

Directory of Open Access Journals (Sweden)

Stanley G. Selig

2015-01-01

Full Text Available A finite element simulation of the compaction and springback of an aluminum-based powder metallurgy alloy (Alumix 321 was developed and validated using the LS-DYNA hydrocode. The present work aims to directly address the current scarcity of modeling works on this popular alloy system. The Alumix 321 constitutive material parameters are presented. The model can predict the results of single-action compaction as well as the amount of springback experienced by a compact upon ejection from the die. The model has been validated using a series of experiments including powder compaction, optical densitometry, and the creation of a compaction curve.

Hypervelocity Launching and Frozen Fuels as a Major Contribution to Spaceflight

Science.gov (United States)

Cocks, F. H.; Harman, C. M.; Klenk, P. A.; Simmons, W. N.

Acting as a virtual first stage, a hypervelocity launch together with the use of frozen hydrogen/frozen oxygen propellant, offers a Single-Stage-To-Orbit (SSTO) system that promises an enormous increase in SSTO mass-ratio. Ram acceleration provides hypervelocity (2 km/sec) to the orbital vehicle with a gas gun supplying the initial velocity required for ram operation. The vehicle itself acts as the center body of a ramjet inside a launch tube, filled with gaseous fuel and oxidizer, acting as an engine cowling. The high acceleration needed to achieve hypervelocity precludes a crew, and it would require greatly increased liquid fuel tank structural mass if a liquid propellant is used for post-launch vehicle propulsion. Solid propellants do not require as much fuel- chamber strengthening to withstand a hypervelocity launch as do liquid propellants, but traditional solid fuels have lower exhaust velocities than liquid hydrogen/liquid oxygen. The shock-stability of frozen hydrogen/frozen oxygen propellant has been experimentally demonstrated. A hypervelocity launch system using frozen hydrogen/frozen oxygen propellant would be a revolutionary new development in spaceflight.

Compact Q-balls

Energy Technology Data Exchange (ETDEWEB)

Bazeia, D., E-mail: bazeia@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, 58051-970 João Pessoa, PB (Brazil); Losano, L.; Marques, M.A. [Departamento de Física, Universidade Federal da Paraíba, 58051-970 João Pessoa, PB (Brazil); Menezes, R. [Departamento de Ciências Exatas, Universidade Federal da Paraíba, 58297-000 Rio Tinto, PB (Brazil); Departamento de Física, Universidade Federal de Campina Grande, 58109-970 Campina Grande, PB (Brazil); Rocha, R. da [Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, 09210-580 Santo André (Brazil)

2016-07-10

In this work we deal with non-topological solutions of the Q-ball type in two space–time dimensions, in models described by a single complex scalar field that engenders global symmetry. The main novelty is the presence of stable Q-balls solutions that live in a compact interval of the real line and appear from a family of models controlled by two distinct parameters. We find analytical solutions and study their charge and energy, and show how to control the parameters to make the Q-balls classically and quantum mechanically stable.

Characterization by X-ray tomography of granulated alumina powder during in situ die compaction

Energy Technology Data Exchange (ETDEWEB)