Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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33406 Publications

Drop tower experiments on the thermocapillary drop migration

Galindo, V.; Teuner, M.; Gerbeth, G.; Langbein, D.
  • Contribution to external collection
    Proceedings Drop Tower Days, Bremen, July 8 - 11, 1996, pp. 2 - 10

Permalink: https://www.hzdr.de/publications/Publ-1723
Publ.-Id: 1723


A Risk Evaluation System for Contamined Sites

Ferse, W.; Reitz, T.
  • Contribution to proceedings
    Proc. of the FOURTH INTERNATIONAL WORKSHOP on real-time computing of the environmental consequence of an accident release from a nuclear installation, Aronsborg, Sweden, Oct. 7 - 11, 1996, Paper N ...

Permalink: https://www.hzdr.de/publications/Publ-1722
Publ.-Id: 1722


A Computer System for Evaluation of Contamined Sites

Ferse, W.
  • Other report
    NATO ASI Series: Environment - Vol. 8, Kluver Academie Publishers, 1996

Permalink: https://www.hzdr.de/publications/Publ-1721
Publ.-Id: 1721


MHD turbulence measurements in a sodium channel flow

Eckert, S.; Gerbeth, G.; Langenbrunner, H.; Witke, W.
The knowledge about properties of the anisotropic turbulence in liquid metal flows exposed to an external magnetic field is essential for several technological applications such as the concept of a selfcooled liquid metal blanket for thermonuclear fusion reactors, but also of basic interest for turbulence research. Flow parameters like pressure drop and heat transfer rate are essentially determined by the interaction between the external magnetic field and the liquid metal flow. Several experimental studies revealed that the application of a magnetic field leads not exclusively to a suppression of the turbulent perturbations. Velocity fluctuations remain and demonstrate a distinct anisotropy of the MHD turbulence showing a tendency to become two-dimensional. The properties of the local transport of heat or mass are strongly governed by the anisotropic character of the flow. In this context a number of questions arises regarding the origin, the decay time or the size of the turbulent elements. A typical feature of the two-dimensional turbulence is that the energy becomes concentrated in organised large scale fluctuations. This fact ensures an intensive heat transfer on longer distances. Because of the anisotropy of the electromagnetic dissipation term vortices will be scarcely damped over long distances if their axes are aligned with the magnetic field lines. For practical applications it is important to identify possibilities to promote the formation of such quasi-two-dimensional vortices in order to control the heat or mass transfer rate of the flow. It is well-known that the mentioned perturbations can be generated by rather specific means, for example, mechanical inserts or electrical currents between definitely arranged electrodes, etc.. In this paper we force the turbulence intensity by mechanical means employing a grid of cylindrical bars or flat stripes. Due to the favourable material properties of the used liquid sodium we are able to extend the measurements into the region of high interaction parameters. In this way the obtained results complement the already existing knowledge about the two-dimensional MHD turbulence.
  • Contribution to proceedings
    8th Beer-Sheva Int. Seminar on MHD flows and turbulence, Jerusalem, February 1996, to appear in: Progress in Astronautics and Aeronautics, Ed.: Branover, H; Unger, Y.; Washington

Permalink: https://www.hzdr.de/publications/Publ-1720
Publ.-Id: 1720


Procedure and method of MHD phenomena investigation on juvenile surfaces of liquid metal

Bojarevics, A.; Gelfgat, Y.; Gerbeth, G.; Simanowskis, S.; Mankis, J.
  • Contribution to proceedings
    8th Beer-Sheva Int. Seminar on MHD flows and turbulence, Jerusalem, February 1996, to appear in: Progress in Astronautics and Aeronautics, Ed.: Branover, H.; Unger, Y.; Washington

Permalink: https://www.hzdr.de/publications/Publ-1717
Publ.-Id: 1717


A technical system to improve the operational monitoring of the ukrainian nuclear power plant Zaporosh'ye (Unit 5)

Beyer, M.; Carl, H.; Nowak, K.; Schumann, P.; Seidel, A.; Weiß, F.-P.; Zschau, J.
In order to improve the operational surveillance of a VVER-1000 unit of the Ukrainian nuclear power plant Zaporosh'ye a technical monitoring system has been specified and installed during the last three years.
The technical system enables the operator and supervisory body to monitor the core and the unit continuously during normal and off-normal conditions, to assess the safety status of core and unit, and to impose appropriate measures. The system provides an early indication of any operational incident and of emissions of radioactive materials. Based on the system an immediate warning in emergency situations is possible as well as an effective emergency management. For this purpose 49 different safety related operational parameters of the core and unit - e.g.: neutron flux, pressure - primary and secondary circuit, fuel rod outlet water temperature, boron concentration - primary circuit and so on -, 18 radiological parameters of the unit and the plant side and 6 meteorological parameters are automatically monitored and evaluated.
The system was put into operation at the end of 1995. It is now working under test conditions.
The paper presents the technical solution of the system and the evaluation principles. Additionally the paper gives a short overview about the results obtained during the test operation of the system.
  • Contribution to proceedings
    Proc. of the OECD/NEANSC Specialists' meeting on in-core instrumentation and reactor core assessment, Mito-shi, Japan, Oct. 14 - 17, 1996, Paper-No. 88

Permalink: https://www.hzdr.de/publications/Publ-1716
Publ.-Id: 1716


A technical system to improve the operational monitoring of the Zaporosh'ye nuclear power plant (remote monitoring system in Ukraine - first level of realization)

Beyer, M.; Carl, H.; Schumann, P.; Seidel, A.; Weiß, F.-P.; Zschau, J.; Nowak, K.
A technical system to improve the operational monitoring of the Zaporozh'ye NPP as a tool for the supervisory authority is presented. The system is mainly directed to monitoring the operational data for early detection of, and information about, anomalous events and gives input data for source term estimation. Additionally, radiological data from the site and the environment as well as meteorological data are integrated in the system for pollution transport calculations. Thus the system's information is well suited to becoming a data source for RODOS system.
  • Contribution to external collection
    Proc. of the FOURTH INTERNATIONAL WOKRSHOP on real-time computing of the environmental consequence of an accident release from a nuclear installation, Aronsborg, Sweden, Oct. 7 - 11, 1996, Paper-N ...

Permalink: https://www.hzdr.de/publications/Publ-1715
Publ.-Id: 1715


Mathematisch-numerische Modellierung der Ultraschallstreuung an oberflächenverbundenen Rissen mit dem EFIT-Code

Bergmann, U.
Ein im Forschungszentrum Rossendorf entwickeltes Ultraschall-Laufzeit-Beugungsverfahren zur experimentellen Beobachtung von stabilem Rißwachstum wurde durch Simulationsrechnungen analysiert. Das Meßverfahren umfaßt die quasistatische Belastung einer einseitig angerissenen stabförmigen Probe in Dreipunktbiegung sowie die wiederholte Messung der Laufzeit eines an der Rißfront gebeugten Ultraschallimpulses. In den 2D-Simulationen wurden Probengeometrie, Rißlänge sowie Ultraschallsende- und Empfangswandler berücksichtigt. Gegenstand der Simulationen waren die Erzeugung des Ultraschallimpulses, die Schallfeldausbreitung und die Signalbildung im Empfangswandler mit Hilfe der Elastodynamischen Finiten Integrationstechnik. Den aufeinanderfolgenden Phasen des Dreipunkt-Biegeversuches wurde durch Einbeziehung von zunehmender Rißlänge und Probendurchbiegung, Rißabstumpfung und Materialschädigung Rechnung getragen. Die Simulationsergebnisse ermöglichen folgende Schlußfolgerungen:
  • Die Natur der empfangenen Meßsignale und die Entstehung jedes einzelnen angeregten Echos wurden vollständig aufgeklärt. Es konnte zweifelsfrei nachgewiesen werden, daß es sich bei dem zur Laufzeitmessung herangezogenen Meßsignal tatsächlich um das an der Rißspitze gebeugte Transversalwellen-echo handelt.
  • Durch Variation der Versuchsparameter (Wellenmode, Aperturfläche, Wandlerposition und Meßfrequenz) in den Simulationsrechnungen konnten Informationen über eine mögliche Optimierung der Meßanordnung zur Erhöhung ihrer Meßgenauigkeit und ihres Aussagegehaltes gewonnen werden.
  • Insgesamt bestätigen die Simulationen die gute Eignung des entwickelten Rißfortschrittsmeßverfahrens zu Rißfortschrittsmessungen an Kleinproben aus duktilem Material.
  • Other report
    Nova Acta Leopoldina Supplementum Nr. 14, S. 361-376 (1996)

Permalink: https://www.hzdr.de/publications/Publ-1714
Publ.-Id: 1714


Das Konzept des Ultraschall-Laufzeit-Prozeßablauf-Bildes

Bergner, F.; Bergmann, U.; Fleischer, U.
  • Lecture (Conference)
    Seminar für zerstörungsfreie Materialcharakterisierung, Jena, Oktober 1996, Berichtsband 54, DGZfP, S. 253 - 258
  • Contribution to proceedings
    Seminar für zerstörungsfreie Materialcharakterisierung, Jena, Oktober 1996, Berichtsband 54, DGZfP, S. 253 - 258

Permalink: https://www.hzdr.de/publications/Publ-1713
Publ.-Id: 1713


Simulation der transienten Naturkonvektion in einem seitlich beheizten Behälter

Aszodi, A.
  • Contribution to proceedings
    Jahrestagung Kerntechnik '96, Mannheim, 21. - 23. Mai 1996, Tagungsbericht S. 106 - 109

Permalink: https://www.hzdr.de/publications/Publ-1712
Publ.-Id: 1712


Plasma confinement and stability studies in the gas-dynamic trap experiment

Anikeev, A.; Noack, K.; Kumpf, H.; Krahl, S.; Otto, G.; Bagryansky, P. A.; Deichuli, P. P.; Ivanov, A. A.; Karpushov, A. N.; Maximov, V. V.; Shichovtsev, I. V.; Stupishin, N. V.; Tsidulko, Y. A.; Voropaev, S. G.; Murakhtin, S. V.
  • Poster
    16th IAEA fusion energy conferency, Montreal, Canada, October 7 - 11, 1996, Proceedings Vol. II, pp. 283-291, IAEA-CN-64/CP-22
  • Contribution to external collection
    16th IAEA fusion energy conferency, Montreal, Canada, October 7 - 11, 1996, Proceedings Vol. II, pp. 283-291, IAEA-CN-64/CP-22

Permalink: https://www.hzdr.de/publications/Publ-1711
Publ.-Id: 1711


High Resolution Void Fraction Measurements for the Validation of Flow Maps and CFD Codes

Krepper, E.; Krüssenberg, A.-K.; Prasser, H.-M.; Schaffrath, A.
The present work is aimed at the investigation of two-phase flow in vertical pipes. Even under these very simple boundary conditions, strong 3D effects are observed. The distribution of the gas phase over the cross section varies significantly between the different flow patterns, which are known for the vertical two-phase flow. The paper presents a new device for measuring the void distribution with a high resolution (242 mea-suring points in a cross section area, measuring frequency approx. 1 kHz). This high resolution allows the calculation of local and averaged void fractions, a flow pattern visualization and the determination of bubble size distributions. Bubble flow appears with void center and boundary maximum distribution. The bubble size distribution allows the classification of the transition from homogeneous to inhomogeneous bubble flow and bubble to slug flow. These criteria are compared with selected empirical or theoretical flow pattern maps. The measurements are also used to assess the capability and the accuracy of the code CFX-4.2. The 3D calculations were still only successful for bubble flow, while the experiments were carried out in a wide range of superficial velocities, including other flow patterns like plug or churn turbulent flow.


Keywords: high resolution void fraction measurement, CFD-code validation, flow maps
  • Lecture (Conference)
    2nd International Symposium on Two phase Flow Modelling and Experimentation, Pisa May 1999, Proc. Vol. III, pp. 1371-1378, ISBN: 88-467-0177-1
  • Contribution to proceedings
    2nd International Symposium on Two phase Flow Modelling and Experimentation, Pisa May 1999, Proc. Vol. III, pp. 1371-1378, ISBN: 88-467-0177-1

Permalink: https://www.hzdr.de/publications/Publ-1710
Publ.-Id: 1710


Experimental and Analytical Investigation of the Operation Mode of the Emergency Condenser of the SWR1000

Schaffrath, A.; Hicken, E. F.; Jaegers, H.; Prasser, H.-M.
The Siemens AG is developing the new innovative boiling water reactor concept SWR1000. New features are the passive safety systems (e.g. emergency condensers, building condensers, passive pressure pulse transmitters, gravity-driven core flooding lines).

For the experimental investigation of the emergency condenser effectiveness, the NOKO test facility has been constructed at the Forschungszentrum Jülich in cooperation with Siemens. This test facility has an operating pressure of 10 MPa and a maximum power of 4 MW for steam production. The emergency condenser bundle consists of eight tubes and is fabricated with planned geometry and material of the SWR1000. In more than 200 experiments, the emergency condenser power was determined as a function of pressure, water level and concentration of noncondensables in the pressure vessel as well of pressure, water level and temperature in the condenser.

Post test calculations of NOKO experiments were performed with an improved version of ATHLET. To calculate the heat transfer coefficients during condensation in horizontal tubes it was necessary to develop the module KONWAR and to implement it in ATHLET. KONWAR is based on the flow regime map of Tandon and includes several semiempirical correlations for the determination of the heat transfer coefficients. The comparison bet-ween calculations and experiments shows good agreement.

Keywords: SWR1000, emergency condenser, ATHLET, KONWAR, condensation inside horizontal and slightly inclinde tubes
  • Nuclear Technology 126 (1999), May 1999, p. 123-142

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Permalink: https://www.hzdr.de/publications/Publ-1709
Publ.-Id: 1709


Experimentelle Untersuchungen zur Wirksamkeit passiver Komponenten für den SWR1000

Schaffrath, A.; Fethke, M.; Ringel, H.
Am 29. Oktober 1998 veranstaltete die Ortssektion Sachsen der Kerntechnischen Gesellschaft e.V. an der TU Dresden ein Seminar zum Thema "Experimentelle Untersuchungen zur Wirksamkeit passiver Komponenten für den SWR1000". Diese Thematik erhielt u.a. durch das von Siemens beantragte standortunabhänige Prüfverfahren (vgl. atw 43 (1998), Nr. 10, S. 650) sowie der am 5. November in Königswinter durchgeführten KTG-Tagung "SWR1000 - ein zukunftsweisendes Reaktorkonzept" eine besondere Aktualität. In dem derzeit von der Siemens AG entwickelten innovativen Siedewasserreaktor SWR1000 werden zur Erhöhung der Sicherheit und der Wirtschaftlichkeit aktive Sicherheitssysteme weitestgehend durch passive ersetzt oder mit diesen kombiniert. Hierzu zählen die nachfolgend im Detail beschriebenen Systeme Notkondensator, Gebäudekondensator sowie Passiver Impulsgeber.


Keywords: SWR1000, passive Sicherheitssysteme, Notkondensator, Gebäudekondensator, passiver Impulsgeber, Kerntechnische Gesellschaft
  • atomwirtschaft - atomtechnik 44 (1999)1, S. 35-36
  • Lecture (others)
    Seminar "Experimentelle Untersuchungen zur Wirksamkeit passiver Komponenten für den SWR1000", TU Dresden, 29. Oktober 1998

Permalink: https://www.hzdr.de/publications/Publ-1708
Publ.-Id: 1708


Comparative assessment of condensation models for horizontal tubes

Schaffrath, A.; Krüssenberg, A.-K.; Lischke, W.; Gocht, U.; Fjodorow, A.
The condensation in horizontal tubes plays an important role e.g. for the determination of the operation mode of horizontal steam generators of VVER reactors or passive safety systems for the next generation of nuclear power plants. Two different approaches (HOTKON and KONWAR) for modeling this process have been undertaken by For-schungszentrum Jülich (FZJ) and University for Applied Sciences Zittau/Görlitz (HTWS) and implemented into the 1D-thermohydraulic code ATHLET, which is developed by the Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) mbH for the analysis of anticipated and abnormal transients in light water reactors. Although the improvements of the condensation models are developed for different applications (VVER steam generators - emergency condenser of the SWR1000) with strongly different operation conditions (e.g. the temperature difference over the tube wall in HORUS is up to 30 K and in NOKO up to 250 K, the heat flux density in HORUS is up to 40 kW/m² and in NOKO up to 1 GW/m²) both models are now compared and assessed by Forschungszentrum Rossendorf e.V. Therefore post test calculations of selected HORUS experiments were performed with ATHLET/KONWAR. It can be seen that the calculations with the extension KONWAR as well as HOTKON improve significantly the agreement between computational and experimental data.

Keywords: VVER Steam Generators, Condensation inside Horizontal Tubes, ATHLET
  • Kerntechnik 64 (1999) 4, p. 204-208

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Permalink: https://www.hzdr.de/publications/Publ-1707
Publ.-Id: 1707


Verifizierungsuntersuchungen zur Detektion von Rißinitiierung bei duktilem Materialverhalten unter schlagartiger Belastung

Richter, H.
  • Other report
    Abschlußbericht zum Forschungsaufenthalt am VTT Espoo (Finland) an die Deutsche Akademie der Naturforscher Leopoldina, Juli 1997

Permalink: https://www.hzdr.de/publications/Publ-1706
Publ.-Id: 1706


Dodewaard core - Reactor physical modelling and neutron kinetic computer simulations. Progress report on the application of the coupled code DYN3D-ATHLET.

Mittag, S.
  • Other report
    BWRCA report 4.1.6-2, August 1997

Permalink: https://www.hzdr.de/publications/Publ-1704
Publ.-Id: 1704


Quasi-elastic ligth scattering from capillary waves at the liquid metal surface

Kolevzon, V.
Free surfaces of liquid gallium and mercury were studied by light scattering from thermally exited capillary waves. Great precautions were taken to prepare an oxide-free liquid metal surface inside a small evacuated container. Experimental results are shown in the form of q dependencies of the wave peak frequency wo and the damping constant ?. The observed damping constants of capillary waves differ greatly from those predicted by the classical theoretical treatment of Hg and Ga surfaces as those of simple liquids. This effect is explained in terms of the presence of a surface layer of highly correlated atoms accompanying the liquid-vapor transition. Viscoelastic properties of surface layer are extracted from the fit of experimental spectra with a theoretical form utilizing a well known phenomenological model. Results of the fit demonstrate that the surface viscosity appears to be negative. This implies that the widely used phenomenological model should be replaced by another one incorporating the Maxwell viscoelastic model. Special point has been made on studying the temperature dependence of the wave peak frequency at the free and oxidized Hg surface. This dependence emphasizes negative derivative of the surface tension d?/d? linked with the spatial distribution of free electrons being much
stronger temperature dependent than local surface ordering recently revealed at the mercury-vapor interface. In contrast, ?o(?) dependence collected at the Hg-HgO interface displayed two principally different tendencies: it increased steadily on the Hg surface covered with an oxide monolayer but was nearly constant at the surface covered with a polymolecular film of HgO. This behavior is discussed in the framework
of various theoretical models.
  • Other report
    Dissertation, TU Berlin, Juli 1997

Permalink: https://www.hzdr.de/publications/Publ-1703
Publ.-Id: 1703


Summary Technical Report of PMK-2 Test No. 2:Pressuriser Surge Line Break Verifikation Report

Horche, W.; Krepper, E.; Schäfer, F.; Trostel, I.
The report deals with the results of ATHLET post-test calculations for an experiment at the Hungarian integral test facility PMK-2. The experiment „pressurizer surge line break" was carried out within the PHARE 4.2.6b project. The primary objective of this test was to provid data for the phenomena associated with a pressurizer surge line break transient. The post-test analyses were performed with ATHLET mod1.1 Cycle C by the Forschungszentrum Rossendorf (FZR) and with ATHLET mod1.1 Cycle D by the Atomic Research Institute Budapest (KFKI) and the Gesellschaft für Anlagen- und Reaktorsicherheit (GRS).
  • Other report
    Gesellschaft für Anlagen- und Reaktorsicherheit mbH, Garching, Nov. 1997

Permalink: https://www.hzdr.de/publications/Publ-1702
Publ.-Id: 1702


Upregulation of the Aromatic Amino Acid Decarboxylase under Neonatal Asphyxia

Brust, P.; Bauer, R.; Vorieger, G.; Walter, B.; Bergmann, R.; Füchtner, F.; Steinbach, J.; Zwiener, U.; Johannsen, B.
Perinatal hypoxic-ischemic cerebral injury is a major determinant of neurologic morbidity and mortality in the neonatal period and later in childhood. There is evidence that the dopaminergic system is sensitive to asphyxia. However, the respective enzyme activities have not yet been measured in the living neonatal brain. In this study, we hav used F18-labeled 6-fluoro-L-3,4-dihydroxyphenylalanine (FDOPA) together with positron-emission tomography l(PET) to estimate the activity of the aromatic amino acid decarboxylase (AADC), the ultimate enzyme in the synthesis of dopamine (DA), in the brain of newborn piglets. Simultaneously, the cerebral blood flow (CBF) was measured with colored microspheres. Asphyxia elicited an up to threefold increase of the CBF. Despite this, the blood-brdain transfer of FDOPA as well as the clearance rate constants from brain were unchanged. However, the synthesis rate of FDA from FDOPA was significantly increased in frontal cortex, striatum, and midbrain. The increase of the AADC activity and the decrease of monoamine oxidase activity may contribute to the increase of extracellular DA during asphyxia which is expected to be involved in severe disturbances of neuronal metabolism, e.g., by generating free radicals.
Keywords: asphyxia; aromatic amino acid decarboxylase; DOPA; dopamine metabolism; neonatal pigs; positron-emission tomography
  • Neurobiology of Disease 6, (1999) 131-139

Permalink: https://www.hzdr.de/publications/Publ-1700
Publ.-Id: 1700


Darstellung, Strukturen und EPR-Spektroskopie der Rhenium(II)-Thionitrosylkomplexe trans-[Re(NS)Cl3(MePh2P)2] und trans-[Re(NS)Br3(Me2PhP)2]

Voigt, A.; Kirmse, R.; Abram, U.
Abstract. The paramagnetic rhenium (II) thionitrosyl compounds trans-[Re(NS)Cl3(MePh2P)2] and trans-[Re(NS)Br3(Me2PhP)2] are characterized by crystal structure diffraction and EPR spectroscopy. Trans-[Re(NS)Cl3(MePh2P)2] is formed during the reduction of (a) [ReNCl2(MePh2P)3] with disulphur dichloride (S2Cl2) or (b) of mer-[ReCl3(MePh2P)3] with trithiazyl chloride ((NSCl)3). Trans-[Re(NS)Br3(Me2PhP)2-] is the final product of the ligand exchange reaction of mer-[Re(NS)Cl2(Me2PhP)3-] with bromine whereby the metal occurred to be simultaneusly oxidized.
The crystal structure analyses show for trans-[Re(NS)Cl3(MePh2P)2] (monoclinic, C2/c, a = 13.831 (3) C, b = 13.970 (1) C, c = 14.682 (2) C, b = 95.33 (1), Z = 4) and trans-[Re(NS)Br3(Me2PhP)2-] (monoclinic, C2/c, a = 33.292 (5) C, b = 8.697 (1) C, c = 17.495 (3) C, b = 115.65 (1), Z = 8) linear co-ordinated NS ligands (Re - N - S - angles 180° and 174.8°). The metal atom is octahedrally co-ordinated with the phosphine ligands in trans position to each other.
X-band and Q-band EPR spectra of the rhenium (II) thionitrosyl complexes (5d5 "low-spin" configuration, S = 1/2) are detected in the temperature range 295 ³ T ³ 130 K. They are characterized by well resolved 185,187Re hyperfine patterns.
The hyperfine parameters are used to get information about the spin-density distribution of the unpaired electron in the complexes under study.



Keywords: Thionitrosyl compounds, Rhenium complexes, EPR spectroscopy, X-ray structure

  • Zeitschrift für anorganische und allgemeine Chemie

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Permalink: https://www.hzdr.de/publications/Publ-1698
Publ.-Id: 1698


CEMS study of iron disilicide fomation by 57Fe ion implantation into silicon

Dobler, M.; Reuther, H.
Doses from 2 x 1015cm-2 to 2 x 1017cm-2 of 57Fe ions were implanted with 40 keV into n-type Si(111) at 350°C. The iron concentration profiles reach peak maximum concentrations from 0.3 at.% for the lowest dose up to about 34 at.%. For the highest dose a plateau-like profile is formed due to the effect of sputtering. The phase formation of the iron disilicides was studied by 57Fe conversion electron Mössbauer spectroscopy. Depending on the implanted dose two different regions of phase formation are found. For doses £ 1 x 1016cm-2 only the metastable g-FeSi2 is present whereas at values ³ 2 x 1016cm-2 a mixture of a- and b-FeSi2 is formed. The phase composition in this second region is dose dependent and with increasing iron content an enlarged fraction of the b-phase is found. At the highest dose of 2 x 1017cm-2 mostly b-FeSi2 and no a-FeSi2 is present. But additionally to the b-FeSi2 a second component occurs in the Mössbauer spectrum which is observed for the first time. With respect to the iron concentration this subspectrum could be attributed to a new metastable state of the mono silicide. Different annealings of the as-implanted samples at 900°C and 1150°C lead to the formation of the pure b- and a-FeSi2, respectively. Additionally to the measurements of the concentration profiles investigations of the lateral element distributions in the layers were performed with scanning Auger electron microscopy. It can be concluded that during the annealing at 1150°C precipitates of the a-FeSi2 grow in the Si matrix.
  • Nuclear Instruments and Methods in Physics Research B 155 (1999) 468-478

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Permalink: https://www.hzdr.de/publications/Publ-1696
Publ.-Id: 1696


Gekoppelte Berechnungen von Thermohydraulik und Neutronenkinetik

Rohde, U.; Langenbuch, S.
Es wird ein Überblick über den Entwicklungsstand und die Anwendung von Computercodes mit Kopplung von thermohydraulischen Anlagenmodellen von Kernkraftwerken und 3D Neutronenkinetik gegeben. Insbesondere wird auf die Ankopplung von Neutronenkinetikmoduln an den Thermohydraulikcode ATHLET eingegangen. Es werden Arbeiten zur Validierung der Codekomplexe durch Nachrechnung von transienten Prozessen in Kernkraftwerken und internationale Programmvergleiche beschrieben. Die Anwendung von ATHLET mit gekoppelter 3D Neutronenkinetik für Störfallanalysen wird an 2 Beispielen demonstriert. Mit den gekoppelten Programmsystemen sind erstmals konsistente Störfallanalysen ohne zusätzliche konservative Annahmen möglich. Entwicklungsbedarf besteht noch bei der Berücksichtigung von 3D Temperatur- und Borkonzentrationsverteilungen innerhalb des Reaktors,
die den hypothetischen Störfallablauf wesentlich beeinflussen können.
  • Lecture (Conference)
    Jahrestagung Kerntechnik, 18. - 20. Mai 1999, Karlsruhe, Sammelband "Neue Ergebnisse aus F+E zur Fluiddynamik und Reaktorphysik", Inforum Verlagsgesellschaft, Bonn, Juni 1999
  • Contribution to proceedings
    Jahrestagung Kerntechnik, 18. - 20. Mai 1999, Karlsruhe, Sammelband "Neue Ergebnisse aus F+E zur Fluiddynamik und Reaktorphysik", Inforum Verlagsgesellschaft, Bonn, Juni 1999

Permalink: https://www.hzdr.de/publications/Publ-1694
Publ.-Id: 1694


Velocity reconstruction in conducting Fluids from magnetic field and electric potential measurements

Stefani, F.; Gerbeth, G.
A possibility for the determination of velocity fields in conducting fluids is presented. Applying a magnetic field from outside, electric and magnetic fields are induced by the fluid motion. These fields can be measured at the walls and outside the fluid volume respectively. The inverse problem of reconstructing the velocity from the measured electric and magnetic fields is solved using Tikhonov regularization.
  • Inverse Problems, 15 (1999), pp. 771-786

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Permalink: https://www.hzdr.de/publications/Publ-1693
Publ.-Id: 1693


Crystal and solution structure of oxo rhenium(V) complexes with cysteine and cysteine methyl ester

Kirsch, S.; Jankowsky, R.; Leibnitz, P.; Spies, H.; Johanssen, B.
The mono oxo rhenium(V) complexes of cysteine and cysteine methyl ester were synthesised via ligand exchange reaction starting from rhenium gluconate. Unexpectedly, the obtained oxo Re(V) complex with cysteine methyl ester was partially saponified. Both complexes were fully characterised by common analytical techniques in their solid state. Thus, an octahedral complex structure with 2(NH2,S) coordination in the equatorial plane and one carboxyl group bound trans to the oxo group is proven for both compounds by X-ray diffraction. Furthermore, the existence of a dioxo species at higher pH was proven for the first time with this type of ligands by determing the nearest coordination sphere of the rhenium centre in solution at a pH of 12 using extended x-ray absorption fine structure spectroscopy (EXAFS).
  • Book (Authorship)
    Technetium, Rhenium and Other Metals in Chemistry and Nuclear Medicine (Edited by Nicoloni M., Mazzi U.) SGE Editoriali Padova (1999) pp.225-228
  • Journal of Biological Inorg. Chemistry JBIC (1999) 4: 48-55

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Permalink: https://www.hzdr.de/publications/Publ-1692
Publ.-Id: 1692


Strain and SiC particle formation in silicon implanted with carbon ions of medium fluence studied by synchrotron X-ray diffraction

Eichhorn, F.; Schell, N.; Matz, W.; Kögler, R.
  • J. Appl. Phys.Vol. 86 No. 8 (1999) 4184 - 4187

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Permalink: https://www.hzdr.de/publications/Publ-1690
Publ.-Id: 1690


Ring Transformations of Heterocyclic Compounds. XVIII [1]. Spiro[cyclohexadiene-indolines] with Three Stereocenters from Pyrylium Salts and Chiral Methyleneindolines - An Example of a High Diastereoselektive Ring Transformation

Zimmermann, T.; Abram, U.
The diastereoselective synthesis of 6-aroyl-3,5-diarylspiro[cyclohexa-2,4-diene-1,2´-indolines] 4 possessing three stereocenters from 2,4,6-triaryl-pyrylium perchlorates 1 and chiral methyleneindolines 3, generated in situ by deprotonation of the corresponding 3H-indolium perchlorates 2, in the presence of triethylamine/acetic acid in ethanol by a 2,5-[C4+C2] pyrylium ring transformation is reported. Structure elucidation is performed by X-ray structure determinations of the spiro[cyclohexadiene-indolines] 4a, 4p and 4t. The influence of various substituents at C-3 of the methyleneindolines 3 on the stereochemistry of the transformation, mechanistic details as well as spectroscopic data of the products 4 are discussed.
  • Communication in "Anorganische allgemeine Chemie", "J. Heterocylic Chemie"

Permalink: https://www.hzdr.de/publications/Publ-1689
Publ.-Id: 1689


Synthesis and characterization of two P,S,N-coordinated cis-dioxorhenium (V) complexes

Bouziotis, P.; Papadopoulos, M.; Pirmettis, I.; Pelecanou, M.; Raptopoulou, C. P.; Terzis, A.; Stassinopoulou, C.; Friebe, M.; Spies, H.; Johannsen, B.
In the course of our investigations into mixed ligand systems containing thiol residues, we have examined, among others, the reactions of bidentate aminethiols with monodentate thiols, as well as tridentate/monodentate mixed ligand systems in the presence of ReOCl3(PPh3)2. Mixed ligand complexes of the general type "2+1+1" and "3+1" have been isolated. Surprisingly, in our synthetic attempts to clarify the mechanism of such reactions, we revceived two unexpected cis-dioxorhenium(V) P,S,N-coordinated complexes, where the aminethiol acts as a bidentate ligand over the Re(V) precursor. The two novel complexes of the general formula ReO2[R2NCH2CH2S][PPh3] where NR2=NEt2 (Complex 1) and NR2=N(CH2CH2)2C(OCH2)2 (Complex 2) are presented below. Both complexes have been characterized by elemental analysis and spectroscopic methods. Crystallographic studies show that the coordination geometry around rhenium is trigonal bipyramidal with the two cis-oxo groups and the sulfur atom of the ligand occupying the basal plane, while the nitrogen of the ligand and the phosphorus occupy the apical positions.
  • Book (Authorship)
    Technetium, Rhenium and Other Metals in Chemistry and Nuclear Medicine (Edited by Nicolini M., Mazzi U.) SGE Editoriali Padova (1999) pp. 203-208

Permalink: https://www.hzdr.de/publications/Publ-1687
Publ.-Id: 1687


Temperaturtransiente Kriechberstversuche an Zirconium-Niob1-Hüllrohren Vergleich zu Zircaloy-4 Hüllrohren

Erbacher, F. J.; Schmidt, H.; Saey, P.; Häusler, R.; Wetzel, L.; Böhmert, J.; Lübke, L.
In the REBEKA-test facility of the Karlsruhe Research Centre (FZK) temperature-transient single-rod creep burst tests on Zirconium-Niobium 1 (ZrNb1) cladding tubes of Russian VVER reactors have been performed under conditions simulating a loss-of-coolant accident (LOCA). For the time being the test results obtained allow a comparison of the burst behaviour of ZrNb1- and Zircaloy-4 (Zry4) cladding tubes. The burst temperature and burst strains, respectively as influenced by the burst pressure, burst temperature and heating rate exhibit in the phase transformation temperatures which are up to 100 K lower for ZrNb1 compared to Zry4. For a reliable description of the ZrNb1 cladding behaviour in a LOCA further experimental and theoretical research work is needed.
  • Other report
    Wissenschaftliche Berichte Forschungszentrum Karlsruhe, FZKA 5726, Aug. 1997

Permalink: https://www.hzdr.de/publications/Publ-1685
Publ.-Id: 1685


Cylinder wake control by means of electromagnetic forces

Weier, T.; Gerbeth, G.; Mutschke, G.; Lielausis, O.; Platacis, E.
  • Lecture (Conference)
    Int. Workshop on Electromagnetic Boundary Layer Control for Saltwater Flows , Dresden, July 7 - 8, 1997

Permalink: https://www.hzdr.de/publications/Publ-1684
Publ.-Id: 1684


Consideration of Neutron Flux Gradients for Sophisticated Evaluation of Irradiation Experiments

Viehrig, H.-W.; Barz, H.-U.; Böhmert, J.; Böhmer, B.
A joint Russian/German irradiation experiment was performed at the pressurized water reactor VVER 2 of the Rheinsberg NPP (Germany). The experiment comprises about 800 Charpy V-notch, SENB and CT specimens made from 24 different heats of Russian type RPV base and weld metals.
Comprehensive calculations of the neutron fluence were carried out. A multigroup Monte Carlo method allows the calculation of the neutron fluence of each specimen or of different points within a large specimen under consideration of the details of the geometric arrangement. As the calculations shown the neutron fluence considerably varies over the cross section of an irradiation rig. Therefore, influence of the flux gradients on testing of Charpy V-notch and CT-specimens is evaluated.
Methods taking into account a fluence correction of the measured absorbed energies are presented and discussed
  • Lecture (Conference)
    IAEA Specialist's Meeting on Irradiation Effects and Mitigation, Vladimir, Russia, 15 - 19 September, 199, IWG-LMNPP-97/2, Vienna 1997, p. 230
  • Contribution to proceedings
    IAEA Specialist's Meeting on Irradiation Effects and Mitigation, Vladimir, Russia, 15 - 19 September, 199, IWG-LMNPP-97/2, Vienna 1997, p. 230

Permalink: https://www.hzdr.de/publications/Publ-1683
Publ.-Id: 1683


Report on Contribution of the Forschungszentrum Rossendorf e. V. to IAEA Coordinated Research Programme "Assuring Structural Integrity of Reactor Pressure Vessel - CPR Phase IV"

Viehrig, H.-W.; Böhmert, J.
  • Lecture (Conference)
    IAEA Coordinated Research Programme Meeting, Vienna, Austria, October 8 - 10, 1997

Permalink: https://www.hzdr.de/publications/Publ-1682
Publ.-Id: 1682


Anwendung des Master-Curve-Konzeptes

Viehrig, H.-W.
  • Lecture (Conference)
    Vortrag auf der Sitzung der DVM Arbeitsgruppe "Instrumentierter Kerbschlagbiegeversuch", Staatliche Materialprüfanstalt MPA der Universität Stuttgart, 26. September 1997

Permalink: https://www.hzdr.de/publications/Publ-1681
Publ.-Id: 1681


Report on Contribution of the Forschungszentrum Rossendorf e. V. to the Project Reconstitution Techniques Qualification & Evaluation to Study Aging Phenomena of Nuclear Pressure Vessel Materials (RESQUE)

Viehrig, H.-W.; Böhmert, J.
  • Lecture (Conference)
    European Atomic Energy Community, Nuclear Fission Safety, 1st Progress Meeting, Erlangen, Germany, October 14-15, 1997

Permalink: https://www.hzdr.de/publications/Publ-1680
Publ.-Id: 1680


Rossendorf Activation Measurements for the Balakovo-3 Experiment

Stephan, I.
  • Lecture (Conference)
    International Workshop on the Balakovo-3 Interlaboratory Pressure Vessel Dosimetry Experiment, Rossendorf, 2 - 5 September, 1997

Permalink: https://www.hzdr.de/publications/Publ-1679
Publ.-Id: 1679


ATHLET Calculations of Selected Experiments at PMK-2

Schäfer, F.
The report deals with results of ATHLET calculations for the Hungarian test facility PMK-2. The test facilty is a 1:2070 scaled
down model of a VVER-440 reactor. The calculated experiments includes a „inadvertent opening of the pressurizer safety valve"
and a „pressurizer surge line break". Both experiments were carried out within the PHARE 4.2.6b project. For the calculations
the code ATHLET mod1.1 Cycle C was used. The results of the calculations were compared with the experimental data.
  • Lecture (Conference)
    GRS-Project Metting PHARE 4.2.6b, Berlin, 15. 06. 1997

Permalink: https://www.hzdr.de/publications/Publ-1678
Publ.-Id: 1678


Untersuchungen zur Fluiddynamik von Schaum

Schneider, C.
Membranzellen für elektrochemische Reaktionen unter Bildung gasförmiger Produkte (z.B. Chlor, Sauerstoff, Wasserstoff) unterscheiden sich von herkömmlichen Blasensäulenreaktoren durch die Bildung feiner Gasbläschen an der festen Oberfläche der Elektroden und durch eine Begasung der Flüssigkeit über die gesamte Zellenhöhe. Gegenüber reinem Wasser bewirken Zusätze von anorganischen Elektrolyten mit kleinen Anionen eine Behinderung der Koaleszenz der Gasblasen. Zur Untersuchung der Zweiphasenströmung in einer solchen Anordnung wurde eine Nachbildung der Elektrodenreaktion mit Gasentwicklung durch die katalytische Zersetzung von Wasserstoffperoxid an Platin realisiert. Als Blasensäule dient ein Plexiglasrohr mit einem Innendurchmesser von 52 mm. Zentrisch im Rohr ist der Katalysator, ein mit Platin beschichtetes Titanrohr, angeordnet. Der volumetrische Gasgehalt der Dispersion wird mittels über die Säulenhöhe angeordneten Differenzdruckaufnehmer gemessen. Die Volumenstromdichte an Gas steigt linear mit der Säulenhöhe an. Bei kleinen Gasbelastungen (Gasvolumentrom pro aktive Katalysatorfläche) und geringen Eintrittskonzentrationen des Wasserstoffperoxids bildet sich erwartungsgemäß eine homogene Blasenströmung heraus. Ab einem Gasgehalt von ca. 20% gewinnt die Schwarmbehinderung an Einfluß auf die Blasenströmung. Der Gasgehalt der Dispersion wächst überproportional an. Nehmen Gasbelastung und Anfangskonzentration des Wasserstoffperoxids größere Werte an, geht die Blasenströmung in eine Schaumzone über. Im untersuchten Lastbereich erstreckt sich der Schaum bis zu ca. 68% des Reaktionsvolumens. Unabhängig von der örtlichen Volumenstromdichte an Gas werden hier über mehrere hintereinander geschaltete Meßvolumina gleiche Gasgehaltswerte gemessen, d.h. der Zuwachs an eingetragenem Gas wird durch das Anwachsen der mittleren Aufstiegsgeschwindigkeit des Blasenschwarms infolge von Koaleszenz kompensiert. Hinsichtlich seiner Stabilität kann der Schaum als kurzlebig charakterisiert werden. Es wurden Schaumzerfallszeiten im Bereich von 40 Sekunden gemessen.
  • Lecture (Conference)
    GVC-Fachausschuß Mehrphasenströmungen, Würzburg, 25. - 28. Februar 1997

Permalink: https://www.hzdr.de/publications/Publ-1677
Publ.-Id: 1677


Investigations of Natural Circulation Instabilities in VVER-type Reactors at LOCA Conditions

Schäfer, F.
LOCA experiments are characterized by a more or less rapid primary pressure decrease in the early phase of the transient. After
pump coast down natural circulation becomes the dominant decay heat removal mechanism. After leak initiation boiling in the
reactor core leads to formation of two-phase flow conditions in the primary circuit. At these conditions different types of
two-phase flow instabilities can appear. The instabilities play an important role in the behaviour of the primary circuit, because the
instabilities can disturb the decay heat removal from the reactor core.

At the PMK-2 test facility natural circulation instabilities could be detected in 3 different experiments: a 1% cold leg break, a 1%
cold leg break with primary bleed and a surge line break.

With the help of the presented calculations it could be shown, that ATHLET is able to calculate the accident behaviour in a good
agreement with the experimental data. All significant phenomena, such as hot and cold leg loop seal clearing, stagnation of the
natural circulation, phase and mass separation along the facility and especially the natural circulation instabilities are calculated
very well. In some cases the ATHLET calculation provide the more detailed information required to clarify the complex
processes connected with the different kinds of instabilities.
  • Lecture (Conference)
    27th Informal Meeting on Reactor Noise (IMORN-27), Valencia, November 18 - 20, 1997

Permalink: https://www.hzdr.de/publications/Publ-1676
Publ.-Id: 1676


Leistungsmessung an netzgekoppelten PV-Anlagen und Bestimmung des Performance Ratio

Rindelhardt, U.; Teichmann, G.
Verschiedene Methoden zur Ermittlung der STC-Leistung von Photovoltaik-Generatoren aus gemessenen Kennlinien werden vorgestellt und diskutiert. Dabei handelt es sich um Varianten einer ursprünglich auf Blässer zurückgehenden Methode. In nahezu allen untersuchten Fällen wurden Generatorminderleistungen bis zu 25%, in Einzelfällen sogar mehr, festgestellt. Die erzielten Ergebnisse haben Konsequenzen auf die Bewertung von Erträgen von PV-Anlagen.
  • Lecture (Conference)
    1000-Dächer-Workshop TÜV Rheinland, Köln, 16./17. 9. 1997

Permalink: https://www.hzdr.de/publications/Publ-1675
Publ.-Id: 1675


Magnetic stabilization of thermocapillary driven convection

Priede, J.; Gerbeth, G.
  • Lecture (Conference)
    Int. Workshop on Hydrodynamic Aspects of Electron Beam Technologies, Dresden, March 16 -18, 1997

Permalink: https://www.hzdr.de/publications/Publ-1674
Publ.-Id: 1674


Zustandserkennung in Chemieanlagen mit neuronalen Netzen

Neumann, J.; Schlüter, S.; Schmitt, W.; von der Vorst, K.
  • Lecture (Conference)
    DECHEMA-Fachausschuß "Sicherheitsgerechtes Auslegen von Chemieapparaten", Oberhausen, 26./27. November, 1997

Permalink: https://www.hzdr.de/publications/Publ-1673
Publ.-Id: 1673


Covariance Matrices for the Calculated Spectra at the VVER-1000 Cavity

Manturov, G.; Böhmer, B.
  • Lecture (Conference)
    International Workshop on the Balakovo-3 Interlaboratory Pressure Vessel Dosimetry Experiment, Rossendorf, 2 - 5 September 1997

Permalink: https://www.hzdr.de/publications/Publ-1672
Publ.-Id: 1672


Guidelines for the Collection of NPP Measurement Data to be Used in Transient Code Validation

Kyrki-Rajamäki, R.; Mittag, S.
Collecting measurement data of NPP transients will be of key importance for the validation of coupled thermohydraulics / neutron kinetics codes. The transient data should cover relevant effects caused by the interaction between 3D neutron kinetics and thermohydraulics. Data will be collected for both VVER types (VVER­440 and VVER­1000).
  • Lecture (Conference)
    1st Meeting on the CEC PHARE project SRR1-95, Rossendorf, September 1997

Permalink: https://www.hzdr.de/publications/Publ-1671
Publ.-Id: 1671


Simulation von Erwärmungsprozessen in großen Behältern mit dem Code CFX

Krepper, E.
  • Lecture (Conference)
    CFX-Anwendertreffen, Bad Dürkheim, 16./17. September 1997

Permalink: https://www.hzdr.de/publications/Publ-1670
Publ.-Id: 1670


Eine Frischdampfleitungsleckanalyse für den WWER-440 mit dem gekoppelten Programmkomplex DYN3D/ATHLET

Kliem, S.
  • Lecture (Conference)
    4th ATHLET-User Group Meeting, Garching, 11/12 June, 1997

Permalink: https://www.hzdr.de/publications/Publ-1669
Publ.-Id: 1669


Development of an ATHLET Input Data Check for the Dodewaard Reactor

Kliem, S.
  • Lecture (Conference)
    Status Report BWRCA-Meeting, Rossendorf, 27 - 28 October, 1997

Permalink: https://www.hzdr.de/publications/Publ-1668
Publ.-Id: 1668


Proposal on Dynamic Benchmark Problem for Coupled Thermohydraulic/3D Hexagonal Neutron Kinetic Codes

Kliem, S.
  • Lecture (Conference)
    AER Working Group D Meeting, Budapest, 5 - 7 May, 1997

Permalink: https://www.hzdr.de/publications/Publ-1667
Publ.-Id: 1667


CFD-Anwendungen zur Kühlmittelvermischung in Druckwasserreaktoren

Höhne, T.
Um sich ein besseres Bild über die Strömungsvorgänge im Downcomer und im unteren Plenum eines Druckwasserreaktors machen zu können, wurde mit einem CFD-Code (CFX 4.1) die Strömung unter möglichst realen Randbedingungen nachgerechnet. Hierfür wurden uns freundlicherweise Meßdaten des Anfahrvorganges der Hauptkühlmittelpumpe des DWR Konvoi zur Verfügung gestellt. Die Nachrechnung realer Anfahrvorgänge des DWR Konvoi mit Hilfe von IBS-Meßdaten zeigten eine relativ gute Durchmischung des Kühlmittels im unteren Plenum. Interessant war es festzustellen, daß das Geschwindigkeitsmaximum im unteren Downcomerbereich wie ein Halbkreis um den angefahrenen Stutzen liegt. Unterhalb dieses Stutzens ist die Geschwindigkeit vermindert.

  • Lecture (Conference)
    CFX-Anwendertreffen, Bad Dürkheim, 16./17. September 1997

Permalink: https://www.hzdr.de/publications/Publ-1665
Publ.-Id: 1665


Einfluß der Zusammensetzung auf die Strahlenversprödung von Eisenlegierungen

Böhmert, J.; Krynkov, A.; Nikolaev, Y. A.; Korolev, Y.; Erak, D. Y.; Gerashenke, S.
The radiation embrittlement of the reactor pressure vessel is highly safety-relevant for VVER-type pressure vessels. The sensitivity against radiation embrittlement depends on the chemical composition of the pressure vessel steel. Using an irradiation experiment at surveillance positions in two Russian VVER 440-type reactors the effects of copper, phosphorus and nickel on the radiation embrittlement should be investigated. For that, eight mock-up alloys were selected. Their chemical composition varied between 0.015 and 0.42 % Cu, 0.002 and 0.039 % P, 0.01 and 1.98 % Ni, 0.09 and 0.37 % Si, and 0.35 and 0.49 % Mn. Charpy-V impact tests and tensile tests were performed with specimens machined from these alloys. The specimens were tested in the as-received state, in the irradiated state (fluence: 1x1019 and 8x1019 /cm2 [E>0.5 MeV]) an in the post-irradiation annealed state. In the as-received state, the alloys have a ferritic microstructure. Apart from Cu, the alloyed elements are solved in the matrix.
Irradiation produces strong hardening and embrittlement. The effect increases with the Cu and P content. Ni causes an additional embrittlement. It is independent on the Ni concentration within the range of 1.1 to 2 % Ni and results in a shift of the ductile-brittle transition temperature of about 120 °C after a fluence of 1x1019 /cm2 by a flux of 4x1011 /cm2s. The shift does not depend on the Cu or P content. Furthermore the upper shelf energy is especially reduced by the Ni-rich alloys. For very low content of Cu and P these relations are not valid. The irradiation effect can be eliminated by annealing at 475 °C /100 h. For high content of Cu or P the recovery is incomplete, it remains a residue of 20 to 25 % of the irradiation effect. Ni has no influence on the recovery.
Comparing the results of this study with the ones of the surveillance programmes of the VVER 440-type reactors, the alloys with low Ni content show the same irradiation behaviour as the weld metal. For the Ni rich alloys such well-walidated references are missing.
The experiment is part of an extended research programme. It supposed to continue in order to gain information about the synergistic effects of these elements.
  • Open Access Logo Wissenschaftlich-Technische Berichte / Forschungszentrum Rossendorf; FZR-255 Februar 1999

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Permalink: https://www.hzdr.de/publications/Publ-1664
Publ.-Id: 1664


Kleinwinkelstreuexperimente mit Neutronen- und Synchrotronstrahlung zur Untersuchung der strukturellen Mechanismen der Neutronenversprödung

Große, M.
  • Lecture (Conference)
    Paul Scherrer Institut Villingen, 21. 10. 1997

Permalink: https://www.hzdr.de/publications/Publ-1663
Publ.-Id: 1663


SANS Investigations of the Irradiation-induced Microstructural Changes in Surveillance Specimes of VVER-440-Type Reactor Pressure Vessel Steel 15Kh2MFA and Weld Metal Sv-10MFT

Große, M.; Denner, V.; Böhmert, J.; Mathon, M.-H.
Two mechanisms are proposed for the theoretical description of the dilational viscoelasticity on a liquid surface. Possible relaxations of the temperature and electric charges induced due to the passage of the transverse-longitudinal surface waves are discussed. The dilational viscosity of the liquid metal surface can be realistically estimated from the charge oscillations model.
Keywords: Liquid surface; Surface tension; Viscoelaticity
  • Poster
    Table Ronde LLB Saclay, November 1997, Posterbeitrag

Permalink: https://www.hzdr.de/publications/Publ-1662
Publ.-Id: 1662


Destabilizing actions of staedy magnetic fields

Gerbeth, G.
Usually the action of steady magnetic fields on electrically conducting flows is a damping one. But several examples exist where additional instabilities are due to the magnetic field influence. Such examples will be listed up based on a classification of the various MHD actions. The physical reason for these phenomena and possible applications will be discussed.
  • Lecture (Conference)
    3rd Int. Conference on Transfer Phenomena in Magnetohydrodynamic & Eletroconducting Flows, Aussois, France, Sept. 22 - 26, 1997

Permalink: https://www.hzdr.de/publications/Publ-1661
Publ.-Id: 1661


The Dresden Innovationskolleg on Magnetofluiddynamics

Gerbeth, G.
  • Lecture (Conference)
    Int. Workshop "The use fo magnetic fields in metallurgy and metals processing", Frankfurt/Main, Oct. 1 - 2, 1997

Permalink: https://www.hzdr.de/publications/Publ-1660
Publ.-Id: 1660


Destabilizing actions of steady magnetic fields on electrically conduction flows

Gerbeth, G.; Eckert, S.
The application of an external magnetic field to the flow of any electrically conducting fluid can drastically change the flow characteristics, particularly for highly conducting fluids like liquid metals or semiconductor melts. If the magnetic field is steady there is the general expection that the magnetic field influence is a damping one: suppression of instabilities, turbulence damping up to relaminarization, suppression of vortex shedding, etc. Indeed, several metallurgical applications of magnetic fields are based on the assumption that this action always consists of a strong damping. The primary action of a steady magnetic field is an anisotropic redistribution of vorticity. If this results in flow damping depends strongly on the question how the induced electric currents can close in the liquid volume. In the present lecture we give some examples from our research projects in the field where a destabi-lizing action of a steady magnetic field was found, even resulting in a serious increase of turbulence intensity for increasing magnetic field. First example is a simple liquid metal duct flow. Experimental results will be presented showing that by a suitable promotion of vorticity parallel to the magnetic field lines the turbulence intensity (and correspondingly the heat & mass transfer) is increased by factors 4 to 10 compared to both the non-magnetic case and the case without turbulence promoters. The turbulence intensity can even increase with growing distance from the turbulence promoter. A physical interpretation will be given. Second example is the standard hydrodynamic problem of a flow around a circular cylinder. 2-D and 3-D numerical simulations will be presented showing clearly the suppression of the Karman vortex street due to the magnetic field influence, but also the destabilizing magnetic field action: 3-D instability is found for Re=180, a Reynolds-number where the pure hydrodynamic flow is known to be 3-D stable. Due to the magnetic field action the Squire Theorem is no more valid and, indeed, 3-D instability is found at parameters where the flow is 2-D stable. Physical interpretation and comparison with experimental results will be given. Further examples for a destabilizing magnetic field action will be briefly mentioned: flows driven by thermoelectricity, steady magnetic field influence on an inductively stirred melt. These experimental results will mainly be shown by video sequences.
  • Lecture (Conference)
    3rd European Fluid Mechanics Conference EUROMECH, Göttingen, Sept. 15 - 18, 1997

Permalink: https://www.hzdr.de/publications/Publ-1659
Publ.-Id: 1659


Prediction of the morphology of the As-implanted damage in silicon using a novel combination of BCA and MD simulations

Posselt, M.
In order to predict type and amount of defects created by keV ions under realistic implantation conditions a combination of computer simulations based on the binary collision approximation (BCA) with classical molecular dynamics (MD) calculations is proposed. Time-ordered BCA simulations are applied to ballistic processes with characteristic energies above several 10 eV. Athermal, rapid thermal, and thermally activated processes with lower characteristic energies are treated by MD simulations. They yield the as-implanted defect state formed several 10 ps after ion impact. The MD calculations are performed in cells which are much smaller than the entire volume of the collision cascade of an incident ion but much larger than the distance between nearest neighbour atoms in the lattice. The as-implanted damage produced by a single ion in a certain cell is found to be completely determined by the nuclear energy deposition of the ion into the cell. Therefore, the MD calculations need to be performed
only in one cell for different values of nuclear energy deposition, and statistical considerations based on BCA simulations can be employed to obtain the depth profile and the total number of different defect species (vacancies, interstitials, disordered atoms, etc.) created on average per incident ion.
The novel simulation method is applied to investigate the damage morphology produced by 15 keV B, 30 keV P, and 15 keV As implants.
  • Contribution to proceedings
    Proceedings 1st ENDEASD Workshop Santorini, Greece, April 21-22, 1999, S. 308-318
  • Lecture (Conference)
    Proceedings 1st ENDEASD Workshop Santorini, Greece, April 21-22, 1999, S. 308-318
  • Materials Science in Semiconductor Processing 3 (2000) 317-323

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Permalink: https://www.hzdr.de/publications/Publ-1658
Publ.-Id: 1658


Möglichkeiten und Grenzen der Entscheidungsanalyse bei der Unterstützung von öffentlichen Entscheidungen

Ferse, W.
  • Lecture (Conference)
    Workshop "Nachhaltigkeit - Leitbild für die Wirtschaft", Zentrum für Interdisziplinäre Technikforschung der Technischen Universität Dresden, Dresden, 24. - 26. September 1997

Permalink: https://www.hzdr.de/publications/Publ-1657
Publ.-Id: 1657


Das wissensbasierte System XUMA-GEFA für Altlasten: Vom Prototyp zum Produktionssystem

Ferse, W.; Geiger, W.; Reißfelder, M.; Reitz, T.; Schneider, U.; Weidemann, R.
  • Lecture (Conference)
    11. Internationales Symposium der Gesellschaft für Informatik, Straßburg, 10. - 12. September 1997

Permalink: https://www.hzdr.de/publications/Publ-1656
Publ.-Id: 1656


Die Anwendung wissensbasierter Methoden bei der Bewertung von Altlasten XPS'97

Ferse, W.; Reitz, T.
  • Lecture (Conference)
    4. Deutsche Jahrestagung Wissensbasierter Systeme, Bad Honnef, März 1997

Permalink: https://www.hzdr.de/publications/Publ-1655
Publ.-Id: 1655


Erweiterung des GEFA-Wissenserwerbes für Rüstungsaltlasten

Ferse, W.
  • Lecture (Conference)
    Seminar der Rüstungsaltlastenvertreter der neuen Bundesländer, Umweltbundesamt Berlin, Januar 1997

Permalink: https://www.hzdr.de/publications/Publ-1654
Publ.-Id: 1654


Experimental results on Marangoni flows at a gallium surface

Cramer, A.; Bojarevics, J.; Gelfgat, Y.; Gerbeth, G.
Main objective of this experimental development was to provide a cavity filled with a free-surface liquid metal in order to perform model experiments with low Prandtl-number fluids. The main technical problem was to avoid or, at least, to control oxidation of the liquid metal surface. This was solved by a novel finite volume technique which will be described in the lecture. Liquid Gallium was chosen as model fluid. A controlled amount of oxides was used as tracer at the other-wise free Ga surface. The following phenomena were up to now studied with the help of this container:
  • Marangoni flows and their instabilities due to an imposed thermal gradient
  • thermoelectrically driven flows,
  • oscillating melting and solidification fronts.
Most of the results will be presented in video form. Surprisingly, the Marangoni flow direction is for small temperature differences from hot to cold corresponding to a positive derivative and a maximum in the surface tension temperature dependence. Main conclusion is that this technique providing a controlled free liquid metal surface represents a novel experimental approach to study low Prandtl-number thermocapillary flows, solidification, instabilities or thermoelectricity on the level of model experiments.
  • Lecture (Conference)
    Int. Workshop on Hydrodynamic Aspects of Electron Beam Technilogies, Dresden, March 16 - 18, 1997

Permalink: https://www.hzdr.de/publications/Publ-1652
Publ.-Id: 1652


Magnetic field stabilization of melt extraction processes

Cramer, A.
  • Lecture (Conference)
    Int. Workshop "The use of magnetic fields in metallurgy and metals processing", Frankfurt/Main, Oct. 1 - 2, 1997

Permalink: https://www.hzdr.de/publications/Publ-1651
Publ.-Id: 1651


An experimental technique to investigate themocapillary convection and solid-liquid phase transition in thin metal layer with free surface

Bojarevics, J.; Gelfgat, Y.; Gerbeth, G.
  • Lecture (Conference)
    Symposium on Physical Sciences in Microgravity, St. Petersburg, June 1997

Permalink: https://www.hzdr.de/publications/Publ-1650
Publ.-Id: 1650


Consideration of Environmental Degradation of Reactor Pressure Vessel Steels for the Safety Assessment

Böhmert, J.; Uhlemann, M.
Maintaining the integrity of the reactor pressure vessel (RPV) is of highest safety priority. The task is not trivial because the material is exposed to operation conditions that change the material properties and consequently reduce the safety margins. In the common view, this concerns above all the effects of neutron irradiation, which causes a reduction of the toughness. It is state-of-the-art to monitor the effect by an in-service surveillance programme. Recently, there are results that further environmental degradation effects could be of significance. Primarily the influence of gamma radiation and the irradiation-induced hydrogen embrittlement could also affect the material behaviour. Gamma rays produce a high rate of surviving point defects, which can accelerate ageing embrittlement. Hydrogen reduces the fracture toughness of RPV steels. Enhanced uptake of hydrogen can locally occur due to the radiolysis of water in water-starved condition existing in gaps or cracks. Irradiation defects can trap hydrogen and, thus, the hydrogen concentration can increase additionally. Several results are shown and the consequences for the RPV safety assessment and the embrittlement monitoring are discussed.

Keywords: environmental degradation, hydrogen embrittlement, neutron embrittlement, reactor pressure vessel, safety assessment
  • Lecture (Conference)
    International Conference on Environmental Degradation of Engineering Materials, EDEM 99, 19.-23.09.1999, Gdansk-Jurata, Poland, 167-174
  • Contribution to proceedings
    International Conference on Environmental Degradation of Engineering Materials, EDEM 99, 19.-23.09.1999, Gdansk-Jurata, Poland, 167-174

Permalink: https://www.hzdr.de/publications/Publ-1649
Publ.-Id: 1649


Eignung von [1-11-C]-Acetat als quantitativer Perfusionstracer in der Myokard-PET

van den Hoff, J.; Burchert, W.; Fricke, H.; Meyer, G. J.; Knapp, W. H.
Es wurde die Eignung von [1-11-C]-Acetat zur quantitativen Perfusionsbestimmung in der myokardialen PET untersucht. Bestimmt wurde zum einen die Flußabhängigkeit der Acetatextraktion anhand eines Vergleichs mit dem derzeitigen Standardtracer 13-NH3, zum anderen wurde die statische Güte der mit beiden Tracern abgeleiteten Perfusionswerte untersucht.
  • Lecture (Conference)
    37. Internationale Jahrestagung der Deutschen Gesellschaft für Nuklearmedizin e.V. 14.-17.4.1999 in Ulm
  • Abstract in refereed journal
    Nuklearmedizin 38 (1999) A27

Permalink: https://www.hzdr.de/publications/Publ-1648
Publ.-Id: 1648


Charakterisierung der Stahlenschäden in Reaktordruckbehälterstählen

Böhmert, J.; Große, M.
  • Lecture (Conference)
    Materialwissenschaftliche Tagung WBL, Berlin, Oktober 1997

Permalink: https://www.hzdr.de/publications/Publ-1647
Publ.-Id: 1647


Zerstörungsfreier Nachweis der Strahlenversprödung von Reaktordruckbehälterstählen

Böhmert, J.; Reimche, W.
  • Lecture (Conference)
    3. Sitzung des VGB-Fachausschusses "Werkstoffe und Beanspruchungen", Mannheim, 02.09.1997

Permalink: https://www.hzdr.de/publications/Publ-1646
Publ.-Id: 1646


Summary of the International Workshop on the Balakovo-3 Interlaboratory Experiment

Böhmer, B.
  • Lecture (Conference)
    WGRD VVER - EWGRD Workshop on RPV Neutron Dosimetry, Sandanski, Bulgaria, 29 September - 5 October 1997

Permalink: https://www.hzdr.de/publications/Publ-1645
Publ.-Id: 1645


The "n+1" mixed ligand approach in the design of specific technetium radiopharmaceuticals: Potentials and problems.

Spies, H.; Pietzsch, H.-J.; Johannsen, B.
Investigations concerning the "n+1" concept for the preparation of mixed-ligand technetium and rhenium complexes are briefly summarized. Chemical extensions were made with the aim to get less lipophilic and more stable chelates and involve the search of new precursor molecules, alternative types of tridentate ligands and new synthetic routes. N.c.a. preparation of "3+1" complexes can be done either by ligand exchange at Tc gluconate or in one step starting from pertechnetate. Aspects of reactivity are briefly discussed, particularly the reaction with glutathione in vivo. "n+1" complexes were preferably used for the design of receptor-binding tracers showing that the "3+1" unit seems to be well-suited to be adapted to receptor-affine anchor groups.
  • Book (Authorship)
    Technetium, Rhenium and Other Metals in Chemistry and Nuclear Medicine (Editied by Nicolini M., Mazzi U.) SGE Editoriali Padova (1999) pp. 101-108

Permalink: https://www.hzdr.de/publications/Publ-1644
Publ.-Id: 1644


Rossendorf Spectrum Adjustment for the Balakovo-3 Experiment

Böhmer, B.
  • Lecture (Conference)
    International Workshop on the Balakovo-3 Interlaboratory Pressure Vessel Dosimetry Experiment, Rossendorf, 2 - 5 September 1997

Permalink: https://www.hzdr.de/publications/Publ-1643
Publ.-Id: 1643


Spectrum Adjustment for the Balakovo-3 Experiment

Böhmer, B.
  • Lecture (Conference)
    WGRD VVER - EWGRD Workshop on RPV Neutron Dosimetry, Sandanski, Bulgaria, 29 September - 5 October 1997

Permalink: https://www.hzdr.de/publications/Publ-1642
Publ.-Id: 1642


Anwendung eines Ultraschallverfahrens zur Rißfortschrittmessung in Bruchmechanikversuchen

Bergner, F.; Bergmann, U.
  • Lecture (Conference)
    Institutsseminar, Otto-von-Guericke-Universität Magdeburg, Institut für Werkstofftechnik und Werkstoffprüfung, 27. Mai 1997

Permalink: https://www.hzdr.de/publications/Publ-1641
Publ.-Id: 1641


Rossendorf Monte Carlo Calculations for the Balakovo-3 Experiment and Comparison to Experimental Results

Barz, H.-U.; Konheiser, J.
In this report is described the theoretical and experimental determination of all needed parameters for the neutron exposure of the different specimens that were irradiated in the Rheinsberg reactor within the period from 1984 until 1988 to obtain data for neutron embrittlement studies.
The methodical approach is represented, possible sources of errors are discussed and all the needed results are collected. The work can be divided into a pure calculation part, into the description of the extraction of the monitors and their gamma spectrometric analysis and into the discussion of the spectrum adjustment procedure which combines experimental and theoretical results. Therefore, this representation deals not only with this special task but gives also a survey about the methodical approach and the state of art in Rossendorf for the general problem of determination of neutron fluences, because the developed methods are generally applicable and not limited to the special problem of neutron embrittlement. Different problems with respect of neutron fluences exist also in Germany.
The calculation of fluences is based on an accurate description of the history of the reactor for all irradiation periods, i.e. the time and space dependence of burn up, power and fisson sources. This information was given for a time and space grid of all fuel elements.
For the calculation of the fluences were not used time dependent fluxes, but at first integral sources of fission neutrons are calculated for different fissionable isotopes. Using these given integral source distributions the fluences were calculated and the results from the different fissionable source were composed. For the improvement of the comparison between experimental and theoretical results a special method was used calculating special integral sources for the given detector, because each detector according to its decay notes another integral source resp. flux distribution, which has to be theoretically corrected.
The basis of all transport calculations was the Monte Carlo method in a special problem adjusted kind. Special procedures were developed and successfully applicated for the reduction of statistical errors. Therefore, also for single specimens results with small statistical errors were obtained. It is remarkable that this accurate method which allows a realistic 3-dimensional description of the system reactor-surroundings could be applied with reasonable calculation times for the great number of needed calculations.
To reduce the uncertainties connected by using of group cross sections some calculations with different group sets are performed. It could be shown, that for the Russian ABBN-78 group data (10 groups within the relevant energy range) and the group data on the base of JEF-1 (123 energy groups) a very good agreement could be realized. Also the application of the known code MCNP with a further independent data base gave the same results within the statistical errors. Furthermore we have used for tests the newest Russian group data MULTIK-90, which we have obtained from the Phys. Energetic Institute Obninsk.
Besides the standard CT1-, Charpy- and tension-specimens were irradiated CTX-, CT05- and CT5-specimens, too. The usual positions of these irradiations were the so-called Target channels. For some cases the Irradiation or Surveillance channels have been used, too.
The experimental determination of the neutron fluences was performed by the gamma spectrometric analysis of the used activation detectors. For the Russian detectors the elements Fe, Cu and Nb were used. For some measurements detectors from Rossendorf were applied. The contents of these detectors are Ti, Fe, Ni, Co, Cu, and Ag. Additionally 103Rh was used, too.
All the methods for the analysis of experiments have been enlarged and improved, because many difficulties beginning with the extraction of detectors and their bad consistency had to be overcome. An essential problem was the est ...
  • Lecture (Conference)
    International Workshop on the Balakovo-3 Interlaboratory Pressure Vessel Dosimetry Experiment, Rossendorf, 2. - 5. September 1997

Permalink: https://www.hzdr.de/publications/Publ-1640
Publ.-Id: 1640


High Power Neutral Beam Heating Experiments in the Gas Dynamic Trap

Anikeev, A.; Noack, K.; Otto, G.
The Gas Dynamic Trap (GDT) of the Budker Institute Novosibirsk is an axisymmetrical plasma mirror device with a mirror ration in the range of 12.5-100. It confines a cold and dense target plasma in a collisional regime and a minority of fast ions in a kinetic regime. The target plasma flows out of the central chamber into external MHD-stabilizers where the curvature of the magnetic field lines is favourable with respect to stability against curvature driven MHD flute modes. The research programme of the GDT facility is focused on the generation of the plasma physical data base that is necessary for the GDT based neutron source project proposed by the Budker Institute. The paper reports on the recent upgrade of the neutral beam injection system and on the new plasma parameters achieved by that.
Keywords: mirror plasma device, gas dynamic trap, neutral beam injection, plasma parameters, neutron source.
  • Poster
    24th EPS Conference on Controlled Fusion and Plasma Physics, Berchtesgarden, Germany, june 9 - 13, 1997, Proceedings Vol. 21A, Part I, pp. 385-388
  • Contribution to proceedings
    24th EPS Conference on Controlled Fusion and Plasma Physics, Berchtesgarden, Germany, june 9 - 13, 1997, Proceedings Vol. 21A, Part I, pp. 385-388

Permalink: https://www.hzdr.de/publications/Publ-1639
Publ.-Id: 1639


13N-NH3 PET zur Diagnostik der Transplantatvaskulopathie. Vergleich mit Koronarangiographie und intrakoronarem Ultraschall

Burchert, W.; Wolpers, H. G.; van den Hoff, J.; Hakimi, M.; Meyer, G. J.; Hausmann, T.; Pethig, K.; Knapp, W. H.
ZIEL DER STUDIE: Die Transplantatvaskulopathie (TVP) stellt eine häufige Komplikation im Verlauf nach Herztransplantation dar. Mit der konventionellen Perfusions-Szintigraphie kann diese diffuse Veränderung des koronaren Gefäßbettes nicht zuverlässig erkannt werden. Daher wurde in dieser Untersuchung die regionale myokardiale Perfusion und die koronare Flußreserve mit der 13N-NH3 PET gemessen und mit den Ergebnissen der Koronarangiographie sowie dem intrakoronaren Ultraschall (IVUS) verglichen.
ZUSAMMENFASSUNG UND ERGEBNISSE: Bei Patienten ohne signifikante TVP (angiographisch/IVUS) betrug die Koronarreserve im Mittel 3,0±0,8. Weiterhin fand sich im Vergleich hierzu keine signifikante Verminderung der Flußreserve (2,7±0,8), wenn bei unauffälligem koronarangiographischen Befund nur mit dem IVUS eine <40%ige Stenose nachweisbar war. Bei Patienten mit einer >50%igen koronarangiographischen Stenose kam es zu einer deutlichen Einschränkung der induzierbaren Konarreserve (1,3±0,4;p<0,05). Der minimale koronare Widerstand korrelierte mit dem Stenosegrad, aber nicht mit der Zeit nach der Transplantation. Bei Patienten mit stark erhöhtem koronaren Widerstand fanden sich in der Nachbeobachtungszeit signifikant vermehrte ernste kardiale Ergebnisse.
  • Lecture (Conference)
    37. Internationale Jahrestagung der Deutschen Gesellschaft für Nuklearmedizin e.V. 14.-17.4.1999 in Ulm
  • Abstract in refereed journal
    Nuklearmedizin 38 (1999) A27

Permalink: https://www.hzdr.de/publications/Publ-1638
Publ.-Id: 1638


The German 1000-Roofs-Programme - a Resume of the 5 Years Pioneer Project for Small Grid-Connected PV Systems

Erge, T.; Hoffmann, V. U.; Kiefer, K.; Rössler, E.; Rindelhardt, U.; Teichmann, G.; Decker, B.; Grochowski, J.; Heilscher, G.; Schneider, M.; Blaesser, G.; Ossenbrink, H.; Becker, H.; Vaaßen, W.; Genenning, B.; Rieß, H.; Sprau, P.
Within the framework of the German 1000-Roofs-PV Programme a total of 2056 grid-connected PV systems with a total output of 5,3 MWp were installed on the roofs of private houses. All systems were subjected to a five years measurement programme, 100 systems selected on a statistical basis were equipped with a special measuring system. Besides these long term activities specific work has been carried out on the analysis for low energy yields, the inspection of PV-plants, sociological questions and architectural aspects. All work has been carried out in joint co-operation between Franhofer ISE Freiburg, FZ Rossendorf, ISFH Emmerthal, IST Energietechnik Augsburg, JRC Ispra (Italy), TÜV Rheinland Köln, Umweltinstitut Leipzig and WIP München.
  • Lecture (Conference)
    Proc. of the 2nd World Conference and Exhibition on Photovoltaik Solar Energy Conversion, Vienna (Austria), 6 - 10 July 1998, Vol. III, p. 2648
  • Contribution to proceedings
    Proc. of the 2nd World Conference and Exhibition on Photovoltaik Solar Energy Conversion, Vienna (Austria), 6 - 10 July 1998, Vol. III, p. 2648

Permalink: https://www.hzdr.de/publications/Publ-1637
Publ.-Id: 1637


Untersuchungen von Störungen in einem Semibatch-Versuchsreaktor

Weiß, F.-P.; Hessel, G.; Schmitt, W.; Tefera, N.; von der Vorst, K.; Neumann, J.; Schlüter, S.
Für die sicherheitstechnische Bewertung und ökonomische Betriebsführung von exothermen Semibatch- und Batch-Reaktoren hat die Simulation von Störungen eine entscheidende Bedeutung erlangt. In einem Laborreaktor mit zusätzlich ausgerüsteter Meßlanze werden Störungen bei der säurekatalysierten Essigsäureanhydrid-Methanol-Veresterung untersucht und die gemessenen Temperatur- und Druckverläufe mit den Ergebnissen von Simulationsrechnungen verglichen. Am Beispiel von Rührerfehlern wird gezeigt, daß gegenwärtig auf experimentelle Störungssimulationen zumindest in Laborreaktoren noch nicht verzichtet werden kann.
  • Lecture (Conference)
    Preprints der 3. Merseburger Fachtagung: Automatisierung, Meßmethoden und Experimente in der chemischen Reaktionstechnik, Merseburg, 6./7. November 1997, S. 109 - 116
  • Contribution to proceedings
    Preprints der 3. Merseburger Fachtagung: Automatisierung, Meßmethoden und Experimente in der chemischen Reaktionstechnik, Merseburg, 6./7. November 1997, S. 109 - 116

Permalink: https://www.hzdr.de/publications/Publ-1636
Publ.-Id: 1636


Nondestructive Characterization of Rector Pressure Vessel Materials Using Neural Networks

Schurig, C.; Fiedler, U.; Böhmert, J.
  • Lecture (Conference)
    Proc. of EUROMAT '97, Maastricht, April 1997, p. 347
  • Contribution to external collection
    Proc. of EUROMAT '97, Maastricht, April 1997, p. 347

Permalink: https://www.hzdr.de/publications/Publ-1634
Publ.-Id: 1634


In-situ real-time depth profiling by elastic recoil detection and ist applications to ion nitriding of stainless steel

Kruse, O.; Parascandola, S.; Grötzschel, R.; Möller, W.
A dual beam experiment has been set up combining real-time depth profiling and low-energy ion implantation in order to study the kinetics of ion nitriding. The choice of low energy ion implantation allows precise and independent control of the important ion nitriding parameters ion energy, ion current density, temperature and residual gas composition. Real-time depth profiling is achieved by Elastic Recoil Detection (ERD) using an angle resolving ionization chamber telescope detector. A large solid angle (5.4 msr) allows a fast data acquisition and hence real-time depth profiling with a time resolution of about 30 s combined with a depth resolution of about 10 nm. The capabilities of the setup and its limitations will be discussed. Measurements revealing the role of mechanisms relevant for the nitriding transport during ion nitriding of stainless steel i.e. diffusion, sputtering, absorption of oxygen from the residual gas will be presented.
  • Contribution to proceedings
    Proceedings MRS Spring Meeting San Franciso, USA, 5.-9.4.1999

Permalink: https://www.hzdr.de/publications/Publ-1633
Publ.-Id: 1633


Analysis of a boron dilution accident for WWER-440 combining the use of the codes DYN3D and SiTAP

Rohde, U.; Elkin, I.; Kalinenko, V.
A boron dilution scenario caused by the connection of a previously disconnected primary circuit loop in a Russian WWER­440 type reactor is considered. The scenario is specific for this reactor type because of the existence of Main Isolating Valves in the loops. The additional failure of safety systems during the connection procedure was assumed. The analysis was carried out by the combined use of SiTAP and DYN3D. By the help of the fast running plant simulator code SiTAP several modifications of the scenario were considered. The scenario with the most dangerous consequences was identified and has been analysed using the three­dimensional core model DYN3D including a coolant mixing model for the lower plenum. The boundary conditions for the DYN3D analysis were obtained from SiTAP calculation. Comparing the results of both codes, a similar behaviour of the mean reactor parameters can be observed, but in the 3D analysis local exceeding of safety relevant parameters was obtained. Thus, the point kinetics model is not conservative, but by using SiTAP more realistic time­dependent boundary conditions for the 3D model could be provided than in previous analyses. The strong consequences of the considered scenario suggest the nessecity of additional measures for preventing this type of accidents.

  • Nuclear Engineering and Design 170 (1997), pp. 95 - 99

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Permalink: https://www.hzdr.de/publications/Publ-1632
Publ.-Id: 1632


Zur Physik und Sicherheit von WWER-Reaktoren

Rohde, U.
A brief information about the 7th Symposium of Atomic Energy Research held in
Hoernitz near Zittau (Germany) in September 23-26, 1997, is given. Atomic
Energy Research (AER) is an internatiol association of 23 nuclear power plants,
organisations for scientific-technical support of nuclear authorities and
research institutions from 8 countries on the physics and nuclear safety of
Russian VVER type reactors. At the symposium, about 70 papers were contributed
in sessions on neutron transport methods, core design and reactor operation,
core monitoring, reactor dynamics and reactor safety, waste management and
criticality safety, thermo- and fluid-dynamics.
  • Atomwirtschaft-Atomtechnik 42 (1997) 792

Permalink: https://www.hzdr.de/publications/Publ-1631
Publ.-Id: 1631


Untersuchungen zum Rißeinleitungsverhalten von Stahl unter schlagartiger Belastung mittels Schallemission

Richter, H.
Das kritische J-Integral Ji ist als Zähigkeitsparameter zur Beschreibung der Einleitung des stabilen Rißwachstums (Initiierung) geeignet. Bei erhöhter Belastungsgeschwindigkeit erweist es sich jedoch als schwierig, die Initiierung zu detektieren und einem Punkt auf der Kraft-Durchbiegungs-Kurve zuzuordnen. In dieser Arbeit wird dieser Punkt mittels Schallemission (SE) bestimmt. Die Versuchstechnik zur Ermittlung von Ji umfaßt ein Pendelschlagwerk mit hammerfinnenintegrierter Sonde zur schlagartigen und eine servohydraulische Prüfmaschine mit zusätzlicher Probeninstrumentierung zur dynamischen Belastung von ermüdungsangerissenen Kleinproben in ISO-V-Geometrie.
Es können verschiedene Arten von SE-Signalen beobachtet werden. Ein Signal korrespondiert mit der Rißinitiierung. Der Nachweis für die Initiierung bei Auftreten dieses Signals wird mit unterschiedlichen Mehrprobentechniken geführt.
  • Lecture (Conference)
    Deutsche Gesellschaft für Zerstötungsfreie Prüfung e. V., Statusberichte zur Entwicklung und Anwendung der Schallemissionsanalyse, 11. Kolloquium Schallemission, Jena, 6. - 7. 3. 1997, Berichtsband 58, S. 77
  • Contribution to external collection
    Deutsche Gesellschaft für Zerstötungsfreie Prüfung e. V., Statusberichte zur Entwicklung und Anwendung der Schallemissionsanalyse, 11. Kolloquium Schallemission, Jena, 6. - 7. 3. 1997, Berichtsband 58, S. 77

Permalink: https://www.hzdr.de/publications/Publ-1628
Publ.-Id: 1628


Hydrothermal wave instability of the thermocapillary driven convection in a coplanar magnetic field

Priede, J.; Gerbeth, G.
  • Journal of Fluid Mechanics, Vol. 347, 1997, pp.141 - 169

Permalink: https://www.hzdr.de/publications/Publ-1627
Publ.-Id: 1627


Leitfähigkeitssensoren für die Bestimmung von Parametern einer Zweiphasenströmung

Prasser, H.-M.
Im Institut für Sicherheitsforschung des FZR werden verschiedene Meßverfahren für Zweiphasenströmungen entwickelt. Die Arbeiten sind in der Abteilung Störfallanalyse angesiedelt. Der Ausgangspunkt war die Notwendigkeit von lokalen Dampfgehaltsmessungen bei thermohydraulischen Experimenten zur Kernreaktorsicherheit. Deshalb sind alle Aktivitäten bisher auf die Untersuchung von Flüssigkeits-Gas- bzw. Flüssigkeits-Dampfgemische gerichtet gewesen. Das erste, speziell für den Einsatz bei Störfallsimulationen an sog. integralen Primärkreismodellen von Kernreaktoren mit Druckwasserreaktor entwickelte Meßverfahren waren nadelförmige Leitfähigkeitssonden. Mittlerweile hat sich das Profil hinsichtlich der Zweiphasenmeßtechnik deutlich erweitert. Zu den seit einigen Jahren erfolgreich bei verschiedensten sicherheitstechnischen Experimenten eingesetzten Leitfähigkeitssonden kamen Verfahren, die auf Ultraschall, Positronenemittern und Video-Bildverarbeitungsmethoden beruhen. Was die Leitfähigkeitsmessung betrifft, so wurde in der letzten Zeit ein Gittersensor entwickelt, der eine zeitlich hochauflösende Visualisierung der Strömung in Rohrleitungen ermöglicht. Mit dem Sensors wurde die Kavitation hinter einer Schnellschlußklappe visualisiert, die sich am Anfang einer ca. 200 m langen Rohrleitung befindet. Die Tests fanden an einer Versuchsanlage des Instituts für Umwelt-, Sicherheits- und Energietechnik (UMSICHT) in Oberhausen statt. Über die Methoden hinaus, zu denen eigene Entwicklungsarbeit betrieben wird, werden auch die Kapazitätstomographie (Process Tomography Ltd. Manchester), die Laser-Doppler-Anemometrie, gekoppelt mit einem Laser-Doppler-Partikel-Analysator (LDA/LDPA, Polytech, Aero-metrics) und natürlich die hydrostatische Dichtemessung für Zweiphasenmessungen angewendet.
  • Contribution to HZDR-Annual report
    Workshop "Meßtechnik für stationäre und transiente Mehrphasenströmungen", Rossendorf, 06.-07. November 1997, Forschungszentrum Rossendorf; FZR-204, S. 64 - 71
  • Lecture (Conference)
    Workshop "Meßtechnik für stationäre und transiente Mehrphasenströmungen", Rossendorf, 06. - 07. November 1997

Permalink: https://www.hzdr.de/publications/Publ-1626
Publ.-Id: 1626


A New Wire-Mesh Tomograph for Gas-Liquid Flows

Prasser, H.-M.; Böttger, A.; Zschau, J.
A wire-mesh tomograph for gas-liquid two-phase flows is presented. It is based on the measurement of the conductivity distribution over the cross section of the flow. Two planes of wire grids are placed into the flow in a short distance from each other. The angle between the wires of both grids is 90 °. The conductivity is measured at all cross points of the wires of the two planes. An imaging rate of 1000 frames per second was achieved, the measured data is directly transformed into local volumetric gas fractions without image reconstruction efforts. The minimal conductivity of the liquid necessary for applying the sensor is very low. Pure water (s » 0.5 µS/cm) can be measured without any problems. Up to now, the 2 x 16 wire mesh sensor was tested in a vertical air-water flow.
  • Contribution to proceedings
    Proceedings of the Conference Frontiers in Industrial Process Tomography II, Delft, The Nederlands, April 9 - 12, 1997, pp. 109 -112
  • Poster
    Conference Frontiers in Industrial Process Tomography II, Delft, The Nederlands, April 9 - 12, 1997
  • Lecture (Conference)
    Conference Frontiers in Industrial Process Tomography II, Delft, The Nederlands, April 9 - 12, 1997

Permalink: https://www.hzdr.de/publications/Publ-1625
Publ.-Id: 1625


Two and three-dimensional Instabilities of the Cylinder Wake in an Aligned Magnetic Field

Mutschke, G.; Gerbeth, G.; Shatrov, V.; Tomboulides, A.
2-D and 3-D instabilities in the wake of a circular cylinder placed in an electrically
conducting fluid and subjected to a constant magnetic field aligned with the freestream are investigated numerically. Increasing magnetic fields suppress 2-D instability
(vortex shedding), whereas 3-D instabilities are influenced in a more complex way. In the presence of a magnetic field, 3-D instability has been detected below the 2-D stability threshold. This can lead to a reversal of the order of instabilities, i.e. 3-D instability appears at lower Re than 2-D instability.
  • Physics of Fluids, Vol. 9, 1997, pp. 3114 - 3116

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Permalink: https://www.hzdr.de/publications/Publ-1624
Publ.-Id: 1624


Relaxations of temperature and charges at a liquid metal surface

Kolevzon, V.
  • Physics Letters A 230, 1997, pp. 358 - 362

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Permalink: https://www.hzdr.de/publications/Publ-1622
Publ.-Id: 1622


Temperature.dependent behaviour of capillary waves at Hg-vapour and Hg-HgO interfaces

Kolevzon, V.; Pozniakov, G.
  • Journal of Physics: Condensed Matter, Vol. 9, 1997, pp. 6815 - 6826

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Permalink: https://www.hzdr.de/publications/Publ-1621
Publ.-Id: 1621


The Coupled Code Complex DYN3D/ATHLET - Application to Main Steam Line Break Analysis

Kliem, S.; Grundmann, U.; Rohde, U.
The coupling of advanced thermohydraulic codes with 3-dimensional neutron kinetic codes corresponds to the effort to replace conservative estimations by best estimate calculations. ATHLET is an advanced thermohydraulic code, developed by the German "Gesellschaft für Anlagen- und Reaktorsicherheit" (GRS). The DYN3D code, developed at Forschungszentrum Rossendorf (FZR) for the simulation of reactivity initiated accidents in nuclear reactors with hexagonal and Cartesian fuel element cross section geometry comprises 3-dimensional neutron kinetics, models for the thermohydraulics of the core and the thermomechanical fuel rod behaviour.
The reactor core model DYN3D was coupled with ATHLET according to two basically different strategies. The first way of coupling uses only the neutron kinetics part of DYN3D (internal coupling). In the second way, the whole core is cut out from the ATHLET plant model and is completely described by DYN3D (external coupling). In this case the values of pressure, mass flow rate, enthalpy and boron acid concentration at the bottom and at the top of the core have to be transferred between the codes. This way of coupling is efficiently supported by the General Control and Simulation Module (GCSM) of ATHLET.
The results of the analysis of a main steam line break scenario for a VVER-440 type reactor by the help of DYN3D-ATHLET are presented. The effect of different assumptions for the coolant mixing in downcomer and lower plenum of the reactor has been investigated.
  • Contribution to proceedings
    Proc. Joint International Conference on Mathematical Methods and Supercomputing for Nuclear Applications, pp.1358-1366, ANS, La Grange Park, IL (1997)
  • Lecture (Conference)
    Joint International Conference on Mathematical Methods and Supercomputing for Nuclear Applications, ANS, La Grange Park, IL (1997)

Permalink: https://www.hzdr.de/publications/Publ-1620
Publ.-Id: 1620


Regional distribution of cerebral blood volume and cerebral blood flow in newborn piglets - effect of hypoxia / hypercapnia

Bauer, R.; Bergmann, R.; Walter, B.; Brust, P.; Zwiener, U.; Johannsen, B.
The relationship between regional parenchymal cerebral blood volume (CBV), regional cerebral blood flow (CBF) and the calculated mean transit time (MTT) was investigated in 14 newborn piglets. The effects of combined hypoxic hypoxia (paO2 = 32 ± 5 mm Hg) and hypercapnia ((paCO2 = 68 ± 5 mm Hg) were measured in seven animals. Remaining animals served as the control group. During baseline conditions the highest CBF and CVB values were found in the lower brainstem and cerebellum, whereas white matter exhibited the lowest values (p<0.05). MTT was prolonged within the cerebral cortex (2.34 ± 0.42 s-1) compared with the thalamic MTT (1.53 ± 0,38 s-1) (p<0.05). Under moderate hypoxia/hypercapnia, a CBF increase to the forebrain (p<0.05) resulted in an elevated brain oxygen delivery (p<0.05) and so CMRO2 remained unchanged. Moreover, a moderate increase of CBV and a marked shortening of MTT occurred (p<0.05). The CBV increase was higher in structures with lowest baseline values, i.e., thalamus (66% increase) and white matter (62% increase) (p<0.05). MTT was between 22% of baseline in the lower brainstem and 49% in white matter (p<0.05). We conclude that under normoxic and normocapnic conditions the newborn piglets exhibit a comparatively enlarged intraparenchymal CBV. Moderate hypoxia and hypercapnia induced a marked increase in cerebral blood flow which appears to be caused by an increased perfusion velocity, expressed by a strongly reduced mean transit time and by a concomitant CBV increase.
Keywords: Cerebral blood flow, Cerebral blood volume, Colored microspheres, 99mTechnetium pertechnetate, Newborn piglet
  • Developmental Brain Research 112 (1999) 89-98

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Permalink: https://www.hzdr.de/publications/Publ-1619
Publ.-Id: 1619


Fault Diagnostics in Chemical Semibatch Reactors Using Neural Networks

Hessel, G.; Schmitt, W.; van der Vorst, K.; Weiß, F.-P.; Neumann, J.; Schlüter, S.
This paper presents a neural-network approach to early identifying dangerous states in chemical semibatch reactors. Data sets which were supplied both from a process simulator and from measurements in a laboratory reactor were used to train and test neural networks and a fuzzy pattern classifier for different normal and faulty states. Three-layer perceptron networks were found to be best suited for classifying different normal and abnormal process states. Even multiple fault states can be recognized by the perceptron network correctly.
  • Lecture (Conference)
    Proc. of the 5th European Congress on Intelligent Techniques and Soft Computing EUFIT 97, Aachen, Germany, September 8 - 11, 1997, pp. 1704 - 1708
  • Contribution to proceedings
    Proc. of the 5th European Congress on Intelligent Techniques and Soft Computing EUFIT 97, Aachen, Germany, September 8 - 11, 1997, pp. 1704 - 1708

Permalink: https://www.hzdr.de/publications/Publ-1618
Publ.-Id: 1618


Identification of dangerous states in chemical batch reactors using neutral networks

Hessel, G.; Schmitt, W.; van der Vorst, K.; Weiß, F.-P.; Neumann, J.; Schlüter, S.
This paper presents a neural network approach to the identification and diagnosis of dangerous states in chemical batch reactors. The efficiency of this approach has been proven when monitoring an exothermic chemical process, i.e. the esterification between acetic anhydride and methanol. For training and for testing the state classifiers, data sets delivered both from a process simulator and measurements in a laboratory reactor were used. The classification behaviour of neural networks is compared with fuzzy pattern classification. Results show that perceptron networks might be successfully applied as an additional supervision method to support the operator in making decisions under critical situations.
  • Lecture (Conference)
    Proc. of the IFAC Symposium on Fault detection, supervision and safety for technical processes SAFERPROCESS 97 (Ed.: R. J. Patton), Hull, UK, August 26 - 28, 1997, pp. 926 -931
  • Contribution to proceedings
    Proc. of the IFAC Symposium on Fault detection, supervision and safety for technical processes SAFERPROCESS 97 (Ed.: R. J. Patton), Hull, UK, August 26 - 28, 1997, pp. 926 -931

Permalink: https://www.hzdr.de/publications/Publ-1617
Publ.-Id: 1617


Reconstruction of Pointwise Neutron Flux Distribution in a Hexagonal Cassete - Theoretical Background and Implementation into the Code DYN3D/H1.1

Hadek, J.; Grundmann, U.
The reconstruction of neutron flux density and thermal power density inside the hexagonal cassette of VVER type is described in this paper. The method of succesive smooting combined with folloing analytical solution was used for the detailed pointwise evaluation of neutron fluxes and thermal power densities diestributions in the cassette interior. The program module RECON based on the above mentioned method is presented in the next part of this paper. The results generated by the 3-dimensional reactor dynamic code DYN3D are used as input data for this subprogram. RECON can be used for methodical off-line investigation or to be implemented into the code DYN3D. This implementation is demonstrated at the end of paper.
  • Contribution to proceedings
    Proc. oft the 7th Symposium of Atomic Energy Research, Hörnitz, 23. - 26. 09. 1997, p. 469
  • Lecture (Conference)
    7th Symposium of Atomic Energy Research, Hörnitz, 23. - 26. 09. 1997

Permalink: https://www.hzdr.de/publications/Publ-1616
Publ.-Id: 1616


Neutron Flux Reconstruction ina Hexagonal Cassete - Theory and Implementation into the Code DYN3D/H1.1

Hadek, J.; Grundmann, U.
The reconstruction of neutron flux density and thermal power density inside the hexagonal cassette of VVER type is described. The method of successive smooting combined with following analytical solution was used for the detailed pointwise evaluation of neutron fluxes and thermal power densities distributions in the cassette interior. The program module RECON based on the above mentioned method is presented. Results generated by the 3-dimensional reactor dynamic code DYN3D are used as input data for this subprogram. RECON can be used for methodical off-line investigation or to be implemented into the code DYN3D. This implementation is demonstrated.
  • Nucleon No. 3, (1997), pp. 8 - 14

Permalink: https://www.hzdr.de/publications/Publ-1615
Publ.-Id: 1615


ASAXS-Investigations of the Influence of the Irradiation Temperature on the Formation of Defects in Nuclear Pressure Vessel Steel A-533-B1

Große, M.; Böhmert, J.; Gehrke, R.
  • Other report
    Hamburger Synchrotronstrahlunslabor HASYLAB, Jahresbericht 1996, Hamburg, 1997, S. 255

Permalink: https://www.hzdr.de/publications/Publ-1614
Publ.-Id: 1614


Transiente Strömungsvorgänge in Rohrleitungen, Visualisierung und Berechnung von Kavitationen in Rohrleitungssystemen hinter schnellschließenden Regelklappen

Dudlik, A.; Schlüter, S.; Prasser, H.-M.
  • Contribution to HZDR-Annual report
    Workshop "Meßtechnik für stationäre und transiente Mehrphasenströmungen", Rossendorf, 06.-07. November 1997, Forschungszentrum Rossendorf; FZR-204, S. 39 - 50
  • Lecture (Conference)
    Workshop "Meßtechnik für stationäre und transiente Mehrphasenströmungen", Rossendorf 6.-7. November 1997

Permalink: https://www.hzdr.de/publications/Publ-1613
Publ.-Id: 1613


Transiente Stömungsvorgänge in Rohrleitungen, Messung und Berechnung von Druckstößen und Kavitationsvorschlägen

Dudlik, A.; Schlüter, S.; Prasser, H.-M.
Hervorgerufen durch plötzliche Änderungen der Strömungsgeschwindigkeit treten in Rohrleitungssystemen Druckwellen ("Druckstöße") auf, die wesentlich höher sein können als die im stationären Betrieb vorliegenden Fluiddrücke. Diese sich mit hoher Geschwindigkeit von etwa 900-1500 m/s längs der Rohrleitung ausbreitenden Druckwellen entstehen hauptsächlich durch schnell ausgeführte Regelungs- und Stelleingriffe oder durch Störungen des bestimmungsgemäßen Betriebs. Im Rahmen eines BMBF-geförderten Vorhabens werden experimentelle Untersuchungen an zwei ca. 225 m langen, mit Hoch- und Tiefpunkten ausgestatteten Rohrleitungsschleifen der Nennweiten DN50 und DN100 durchgeführt. Die untersuchten Strömungsgeschwindigkeiten betragen 0,5 bis 5,0 m/s, wobei unterschiedliche Versuchsfluide zum Einsatz kommen. Während der Versuche werden Druckspitzen bis 80 bar, Dampfanteile und lokale Kraftspitzen bis zu 80 kN in hoher zeitlicher Auflösung vermessen. Das Versuchsprogramm umfaßt: Vermessung von Kavitationserscheinungen ("Kavitationsschläge") beim Öffnen und Schließen von Stell-, Regel- und Sicherheitsarmaturen, Einströmen kompressibler und inkompressibler Medien in leere und teilgefüllte Rohrleitungen bei unterschiedlichen Antriebsdrücken bis 40 bar, Ermittlung dynamischer Lagerlasten beim Auftreten von Druckstößen, Kavitationsschlägen und oszillierenden Strömungen (Gas/Flüssigkeitspfopfen). Die Ergebnisse der experimentellen Untersuchungen werden mit Programmen zur Simulation transienter Strömungsvorgänge in Rohrleitungssystemen verglichen (FLOWMASTER, SIR-3S, FLUSTRIN, WANDA, PIPENET, INROS, MONA). Es werden Aussagen zur Genauigkeit der einzelnen Programme und der hierfür erforderlichen Modelltiefe getroffen. Insbesondere werden die Aussagegenauigkeit der implementierten Kavitationsmodelle und die Notwendigkeit einer Berücksichtigung von Fluid-Struktur-Wechselwirkungen für die Planung und den Betrieb verahrenstechnischer Anlagen geprüft.
  • Contribution to proceedings
    Tagung Monitoring und Diagnostik in energietechnischen Anlagen, Braunschweig, 8. - 9. 10. 1997, VDI-Bericht Nr. 1359, S. 353 - 367
  • Lecture (Conference)
    Tagung Monitoring und Diagnostik in energietechnischen Anlagen, Braunschweig, 8. - 9. 10. 1997

Permalink: https://www.hzdr.de/publications/Publ-1612
Publ.-Id: 1612


SANS investigations of the irradiation-caused structural damages in VVER 440-type reactor pressure vessel steels

Böhmert, J.; Große, M.; Nitzsche, P.
Small-angle neutron scattering (SANS) experiments were performed at KWS2 facility of the KFA Jülich for investigating the defect structures, which are produced by neutron irradiation in Russian Cr-Mo-V alloyed reactor pressure vessel steel. Irradiation and post-irradiation annealing considerably change both SANS intensity and its course in the Guinier plot, which was analysed by the Glatter method. As a rule, bimodal size distribution functions were found with a first maximum at a radius of 1-2 nm and a second maximum at 6-8 nm. Irradiation increases the first maximum, annealing reduced it.
  • Physica B 234 - 236 (1997), 997 - 998

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Permalink: https://www.hzdr.de/publications/Publ-1610
Publ.-Id: 1610


A Technical System to improve the Operational and Radiological Monitoring of the Zaporozh'ye Nuclear Power Plant

Beyer, M.; Carl, H.; Nowak, K.; Schumann, P.; Seidel, A.; Weiß, F.-P.; Zschau, J.
As part of the programme implemented by the German Ministry of Environment, Nature Conservation and Reactor Safety to cooperate with the Central and Eastern European States and Commonwealth of Independent States in the area of nuclear safety, a technical system to improve operational monitoring has been designed, specified and established since 1992 as a pilot project by the Research Centre Rossendorf and the Technischer Überwachungsverein Rheinland with a significant contribution from the state scientific and technical centre of the Ukrainian supervisory authority in the Zaporozh'ye/Ukraine nuclear power plant.
The technical system complements existing operational checking and monitoring facilities by including modern means of information technology. It enables concentration on a continuous monitoring of the state of unit 5 in normal operation and in cases of anomalies or incidents so that when recognisable deviations from the regular plant operation occur, the Ukrainian supervisory authority can immediately inquire and if necessary impose conditions on the operator. The radiological and meteorological parameters at the nuclear power plant location are monitored to the extent necessary to assess the current radiation situation and to implement effective emergency management measures.
For this purpose
49 different safety related operational parameters of the core and unit
18 radiological parameters of the unit and the plant site and
6 meteorological parameters
are permanently and automatically recorded, monitored and evaluated.
Test operation of the technical system was commenced at the end of 1995.
Following the completion of the user software by the scientific and technical centre of the Ukrainian supervisory authority and the operator and the establishment of evidence of reliability under nuclear power plant conditions, the industrial testing phase of the system was started in the middle of 1996.
The poster gives an overview about the general cond ...
  • Radiation Protection Dosimetry, Vol 73, pp. 151 - 154 (1997)
  • Contribution to proceedings
    Proc. of the International Topical Meeting on VVER Instrumentation and Control, Prague, Czech Republic, April 21 - 24, 1997, p. 105

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Permalink: https://www.hzdr.de/publications/Publ-1609
Publ.-Id: 1609


Monte Carlo Fluence Calculations and Spectrum Adjustment for the Pressure Vessel of the VVER-1000 Balakovo-3 (Invited Paper)

Barz, H.-U.; Böhmer, B.; Konheiser, J.; Noack, K.; Stephan, I.
The neutron embrittlement problem of current pressure vessel reactors is of great safety and economic concern. It culminates in Russian VVER-type reactors. Compared with Western pressurized water reactors, the shorter distance to the core results in substantially higher neutron fluences for the pressure vessels. In the case of the VVER-1000, the increased content of nickel and the position of a weld at a height near to the maximum flux are additional, unfavorable pecularities. These circumstances caused the embrittlement problem of VVER pressure vessels to become the objective of many international research collaborations. The reactor dosimetry group of Forschungszentrum Rossendorf participated in the Interlaboratory Reactor Dosimetry Experiment Balakovo-3 with Monte Carlo fluence calculations, activation measurements and with spectrum adjustments. The paper describes the specific features of the methods applied, presents and discusses the results and draws conclusions with respect to further investigations.
Keywords: neutron embrittlement, pressurized water reactors, pressure vessel, Monte Carlo fluence calculations, activation measurements, spectrum adjustment, Balakovo-3
  • Lecture (Conference)
    1997 ANS Winter Meeting, Albuquerque, New Mexico, November 16 - 20, Trans. Am. Nucl. Soc., Vol. 77, 1997, pp. 343 - 344
  • Contribution to proceedings
    1997 ANS Winter Meeting, Albuquerque, New Mexico, November 16 - 20, Trans. Am. Nucl. Soc., Vol. 77, 1997, pp. 343 - 344

Permalink: https://www.hzdr.de/publications/Publ-1608
Publ.-Id: 1608


Effect of Wall Conditioning on Neutral Gas Transport in the Gas-Dynamic Confinement System

Bagryansky, P. A.; Noack, K.; Krahl, S.; Collatz, S.
A system of electric arc evaporators for fast Ti-coating has been installed inside the gas dynamic trap (GDT) of the Budker Institute Novosibirsk. In this way the vacuum conditions could be substantially improved and consequently the plasma parameters especially those of the fast ions remarkably increased. The fast ion lifetime raised up by more than one order of magnitude. Under the new conditions special experiments were carried out to study the neutral gas dynamics inside the GDT and to compare with numerical results which were obtained by means of the Monte Carlo code TUBE.
Keywords: electric arc evaporation, Ti-coating, gas dynamic trap, fast ions, neutral gas, Monte Carlo code TUBE
  • Plasma Physics Report, Vol. 23, No. 11, 1997, pp. 903 - 910, Translated from: Fizika Plasmy, Vol. 23, No. 11, 1997, pp. 979 - 987

Permalink: https://www.hzdr.de/publications/Publ-1607
Publ.-Id: 1607


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