Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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39129 Publications

Institute of Radiochemistry; Annual Report 1997

Nitsche, H.; Engelmann, H.-J.; Bernhard, G.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-218
    ISSN: 1436-3976


Publ.-Id: 1182

Structural Investigation of the System Ca2+/UO22+/CO32- by EXAFS

Reich, T.; Geipel, G.; Denecke, M. A.; Allen, P. G.; Bucher, J. J.; Edelstein, N. M.; Shuh, D. K.; Bernhard, G.; Nitsche, H.

  • Other report
    1997 SSRL Annual Activity Report

Publ.-Id: 1180

Gettering of Iron and Oxygen in Helium-Implanted Czochralski (CZ) and Float-Zone (FZ) Silicon

Yankov, R. A.; Kaschny, J. R.; Fichtner, P. F. P.; Mücklich, A.; Kreißig, U.; Danilin, A. B.; Skorupa, W.

  • Poster
    E-MRS 98, Strasbourg, June 16-19, 1998

Publ.-Id: 1179

Study of Ion Beam Assisted Deposition of Al/AlN Multilayers by Comparison of Computer Simulation and Experiment

Wang, X.; Charlamov, V.; Kolitsch, A.; Posselt, M.; Trushin, Y.; Möller, W.

  • Journal of Physics D: Applied Physics 31 (1998) 2241-2244

Publ.-Id: 1178

Thermal Dilepton Signal and Dileptons from Correlated Open Charm and Bottom Decays in Ultrarelativistic Heavy-Ion Collisions

Kämpfer, B.; Gallmeister, K.; Pavlenko, O. P.

  • Book (Authorship)
    Advances in Nuclear Dynamics 4, Edited by W. Bauer and H.-G. Ritter, Plenum Press, New York, 1998, p. 163

Publ.-Id: 1177

Experimentelle Untersuchung turbulenter Flüssigmetall- und Flüssigmetall-Gas-Strömungen in einem äußeren Magnetfeld

Eckert, S.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-219
    ISSN: 1436-3976


Publ.-Id: 1175

Investigation of Dwell-Time Effects on the Cobalt Disilicide Formation Using Focused Ion Beam Implantation

Hausmann, S.; Bischoff, L.; Teichert, J.; Grambole, D.; Herrmann, F.; Möller, W.

The influence of dwell-time effects on the formation of CoSi2 layers was investigated. The layers were produced on Si(111) and Si(100) by ion beam synthesis using a focused ion beam system. The experiments show that the dwell-time has a strong influence on the formation process of the cobalt disilicide films. In order to obtain high quality films suitable for applications short dwell-time (about 1µs) are necessary.

  • Microelectronic Engineering 41/42 (1998) 233-236
  • Lecture (Conference)
    Int. Conf. Micro- and Nano-Engineering, MNE ´97, Athens, Greece, Sept. 15 - 18, 1997

Publ.-Id: 1174

Computer Simulation of Channeling Profile Analysis of Implantation Damage

Posselt, M.

Channeling profile analysis is simulated using the dynamic binary collision code Crystal-TRIM. A good agreement between theoretical and experimental data is found for silicon targets which were predamaged by Si+ ions of different energies and analyzed by 140 keV B+ ions. For each example the depth profile of the defects relevant for the dechanneling of the analyzing ions is given. An estimation on the annealing of such defects is obtained by comparison of results for as-implanted and annealed samples.

  • Contribution to proceedings
    MRS Symposium Proceedings, Mat. Res. Soc. Symp. Proc. Vol. 532, pp. 133-140, 1998 Materials Research Society
  • Lecture (Conference)
    MRS Spring Meeting, San Francisco, CA, USA, April 13-17, 1998

Publ.-Id: 1172

Interactions of Bacteria from a Uranium Mining Waste Pile with U(VI)

Panak, P.; Miteva, V.; Boudakov, I.; Hard, B. C.; Pietzsch, K.; Kutschke, S.; Selenska-Pobell, S.; Bernhard, G.; Nitsche, H.

  • Lecture (Conference)
    Uranium Mining and Hydrogeology II, Freiberg, Germany, 15.-17.09.1998
  • Poster
    Uranium Mining and Hydrogeology II, Freiberg, Germany, 15.-17.09.1998

Publ.-Id: 1171

Wechselwirkung von Bakterien aus Uranhalden mit U(VI) und anderen Schwermetallen

Panak, P.; Miteva, V.; Boudakov, I.; Hard, B. C.; Pietzsch, K.; Kutschke, S.; Selenska-Pobell, S.; Bernhard, G.; Nitsche, H.

  • Lecture (Conference)
    GdCh- Tagung Dresden
  • Poster
    GdCh- Tagung Dresden

Publ.-Id: 1170

Investigation of Bacterial Diversity in Soil of a Depleted Saxonian Uranium Mine via 16S rRNA Gene and 16S/23S Intergenic Spacer Analyses

Puers, C.; Kampf, G.; Selenska-Pobell, S.

  • Lecture (Conference)
    International Symposium on Microbial Ecology ISME-8, Halifax, Kanada, 9.-14.8.1998
  • Poster
    International Symposium on Microbial Ecology ISME-8, Halifax, Kanada, 9.-14.8.1998

Publ.-Id: 1166

Bacterial Diversity in Soil of a Depleted Saxonian Uranium Mine as Revealed by 16S rRNA Gene and 16S/23S Intergenic Spacer Analyses

Puers, C.; Kampf, G.; Selenska-Pobell, S.

  • Lecture (Conference)
    Uran-Bergbau und Hydrologie II, Freiberg, 15.-17.9.1998
  • Poster
    Poster auf der ISME-8, Halifax, Kanada, 9.-14.8.1998

Publ.-Id: 1165

Molecular Studies of Bacterial Diversity in Uranium Wastes

Selenska-Pobell, S.; Boudakov, I.; Flemming, K.; Kampf, G.; Kutschke, S.; Miteva, V.; Otto, A.; Puers, C.; Wober, J.

  • Poster
    Uran-Bergbau und Hydrologie II, Freiberg, 15.-17.9.1998
  • Lecture (Conference)
    Uran-Bergbau und Hydrologie II, Freiberg, 15.-17.9.1998
  • Lecture (Conference)
    8. Internationales Symposium Mikrobielle Ökologie ISME 8, Halifax, Kanada, 9.-14.8.1998
  • Poster
    8. Internationales Symposium Mikrobielle Ökologie ISME 8, Halifax, Kanada, 9.-14.8.1998

Publ.-Id: 1164

Molecular Characterization of Thiobacillus Strains Recovered from Uranium Waste Piles

Kutschke, S.; Selenska-Pobell, S.; Otto, A.; Panak, P.; Geipel, G.; Bernhard, G.; Nitsche, H.

  • Poster
    Uranium Mining and Hydrology II, Freiberg, Germany, 15.-17.9.1998

Publ.-Id: 1163

Comparison of Desulfovibrio Isolates Recovered from a Uranium Waste Heap and Other Environments

Wober, J.; Flemming, K.; Hard, B. C.; Pietzsch, K.; Selenska-Pobell, S.

  • Poster
    Uranium Mining and Hydrogeology II, Freiberg, Germany, 15.-17.09.1998
  • Lecture (Conference)
    Uranium Mining and Hydrogeology II, Freiberg, Germany, 15.-17.09.1998
  • Poster
    Euroconference: Bacterial-Metal/Radionuclide Interaction, Rossendorf/Dresden, Germany, 02.-04.12.1998

Publ.-Id: 1162

Investigations of the Structural Changes Ahead of a Crack Tip in Ductile Aluminium Using Scanning Micro-Beam Small Angle X-Ray Scattering

Große, M.; Böhmert, J.; Riekel, C.

  • J. Material Science Letters 17 (1998) 1631

Publ.-Id: 1161

Anodic Oxidation of the Carbon-14-labelled Organic Waste

Förster, E.; Heise, K.-H.; Nitsche, H.

Barium carbonate is a widely accepted stable chemical form for the safe disposal of carbon-14. This requires, however, oxidation of carbon-14-containing organic waste to carbon dioxide. We habe developed a method for the mineralization of organic compounds by anodic oxidation in silver-sulfate-containing sulfuric-chromic acid. This process can also be used for complete oxidation of "difficult" organic wastes, such as hydrophobic substances like hydrocarbons, plastics, activated carbon, etc. The generation of additional chromium-containing hazardous wastes are avoided in this process by electrolytically regenerating chromium(III) to chromium(VI). The degradation of C-14 labeled organic compounds during the process is monitored by on-line measurement the β-radiation of the produced 14CO2

  • Poster
    13th Radiochemical Conference, Marianske Lazne, 19.-24.4.1998

Publ.-Id: 1160

Characterization of Aquatic Humic Substances from Bog Water and their Complexation Behavior Toward Uranyl Ions

Schmeide, K.; Zänker, H.; Heise, K.-H.; Nitsche, H.

The investigation of the effects of humic substances (humic and fulvic acids) on the migration of radionuclides is important to assess their impact on the long-term safety of both radioactive waste repository sites (e.g. Gorleben, Germany) and abandoned uranium mines (Saxony and Thuringia, Germany).
We extracted humic substances from bog water of the 'Hochmoor Kleiner Kranichsee' which is in the vicinity of the uranium mining sites at Johanngeorgenstadt (Saxony). The humic material was separated into humic and fulvic acid fractions and characterized for its elemental composition, functional properties including proton exchange capacity, charge/size distribution ratios and spectroscopic characteristics. The size and size distribution of humic colloids were studied by photon correlation spectroscopy. Furthermore, the complexation of site specific humic substances with uranyl ions was studied. The results were compared with data of a commercial humic acid from Aldrich.

  • Poster
    13th Radiochemical Conference Marianske Lazne 19.-24.4.1998

Publ.-Id: 1159

Modified Synthetic Humic Acids for the Investigation of Humic Acid Complexation Behavior with Urany(IV) Ions

Pompe, S.; Bubner, M.; Heise, K.-H.; Nitsche, H.

The influence of humic substances on the speciation of actinide ions and their migration behavior in natural aquifer
systems is of great interest within environmental research. Specified knowledge about this is required, for instance, to
develop strategies of risk assessment for long-time safety in the regions of the former uranium mining in Saxony and
Thuringia. Due to the complex and heterogeneous nature of humic substances a thermodynamic founded description of their
complexation behavior with metal ions is difficult. Numerous uncertainties exist in the description of the complexation
process, e.g., the kind and number of complexing functional groups is uncertain. Therefore, it is necessary to
investigate the complexation process with well defined model substances.
We synthesize and characterize humic acid functionality models from reducing sugars and  -amino acids, with functional
properties comparable to those of natural humic acids with respect to type and number of functional groups. Former
measurements have shown that this synthetic humic acids mimic the interaction humic acid - metal ion very well.
This work deals with the possibilities to synthesize modified humic acids, e.g., humic acids with blocked phenolic OH
groups. With this model substances we investigate the influence of phenolic OH groups on the complexation behavior
of humic acids with uranyl ions by time-resolved laser-induced fluorescence spectroscopy. We expect to get a better
understanding of the humic acid - metal ion interaction process and to gather information regarding geochemical
modeling in the presence of humic acids.

  • Poster
    13th Radiochemical Conference Marianske Lazne- Jachymov, 20.-24.04.1998

Publ.-Id: 1158

Melanoidins as Model Humic Acids in Radioecological Research

Heise, K.-H.; Nicolai, R.; Pompe, S.; Bubner, M.; Nitsche, H.

Natural humic acids are instable and chemically not well defined chemical systems. It is difficult to accurately describe their physical-chemical properties. Therefor, studies of the interaction between humic acids and heavy metals, including uranium and other actinide elements, are often limited by this fact. For systematic studies of the interaction processes, stable and wellcharacterized humic acid model compounds have been suggested.
We have separated humic-acid-like fractions with good chemical stability from synthetic melanoidins. It is possible to design the functionality of these melanoidins by varying their precursor substances and the conditions of the synthesis.
Furthermore, we have compared different melanoidins and their interaction with UO2 2+ with the behavior of a commercial natural humic acid (Aldrich) jby infrared spectroscopy (FTIR). The investigation reveals many functional similarities between the melanoidins and the natural humic acid. Comparable symmetric deformation vibrations of uranium in the far infrared range (FIR) indicate similar uranium coordination. In the middle infrared range (MIR), the antisymmetric stretching vibrations of the bound uranium are nearly identical.
In connection with other investigations we have shown, that the melanoidins are excellent humic acid model substances for fundamental radioexological research.

  • Poster
    13th Radiochemical Conference, Marienbad, 19.-24.4.1998

Publ.-Id: 1157

Determination of Dissociation Constants of 99mTechnetium Radiopharmaceuticals by Capillary Electrophoresis

Jankowsky, R.; Friebe, M.; Noll, B.; Johannsen, B.

Capillary electrophoresis was applied to investigate pKa values of 99mTc radiotracers used in nuclear medicine. Therefore, the protonation equilibria of the carboxyl groups of 99mTc- mercaptoacetylglycylglycylglycine (99mTc-MAG3) and 99mTc-ethylenecysteine dimer (99mTc-EC) were studied by pH-dependent determination of electrophoretical velocities. 99methylenecysteine dimer diethyl ester (99mTc-ECD) was used as a non-protonable standard. The capillary electrophoresis system was equipped with a radioactivity detector. Measurements were performed using a pressure-driven capillary zone electrophoresis which allowed runs even in the low pH range. For the determination of pKa values, the electrophoretical velocities of the analytes were referred to the electrophoretical velocities of tetraphenyle arsonium chloride as a positively charged marker. Calculation of pKa values was accomplished by non-linear curve fitting of both structure-based equilibria equations and sigmoidal decay functions to the experimental data. 99mTc-MAG3 was shown to have a carboxyl group pKa value of 4.22. the value for the carboxyl groups of 99mTc-EC is 2.90 (determined by structure-based equilibria equations), which represents a common value for both carboxyl groups. By the use of sigmoidal functions, similar values were elucidated. As expected, 99mTc-ECD shows no protonation step.

Keywords: Dissociation constants; Pharmaceutical analysis; Technetium; Metal complexes

  • Journal Chromatography A, 833 (1999) 83-96

Publ.-Id: 1156

The existence of [ReNF4]- - an EPR study

Voigt, A.; Abram, U.; Kirmse, R.

  • Inorg. Chem. Communications 1 (1998) 141-142

Publ.-Id: 1155

Anwendung wissensbasierter Methoden auf der Grundlage von Insitu-Messung und qualitativer Modellierung zur Optimierung von Schüttguthandhabungstechniken am Beispiel des Dosierens

Lindau, B.

  • Other report
    Freiberger Forschungshefte A 841 Grundstoff-Verfahrenstewchnik 1998, Technische Universität Bergakademie Freiberg Partikeltechnologie: Vorträge und Poster zum 49.Berg-und Hüttenmännischen Tag 1998 in Freiberg, S. 325-333
  • Poster
    49.Berg- und Hüttenmännischer Tag 1998 in Freiberg, S. 325-333

Publ.-Id: 1154

Synthesis and Crystal Structures of [TeI3][GaI4] and [TeI3][InI4]

Schulz-Lang, E.; Vasquez-Lopez, E.; Strähle, J.; Abram, U.

  • Z. anorg. allg. Chem. 624 (1998) 999-102

Publ.-Id: 1153


Schulz-Lang, E.; Pradella-Ziani, J.; Abram, U.

  • Acta Crystallographica (1998) C55, 1010-1011

Publ.-Id: 1152

Reactions of Dichloro[2-(dimethylaminomethyl)phenyl-C1,N]gold(III), [Au(damp-C1,N)Cl2], with heterocyclic thiols. Evidence for Au-N bond cleavage and protonation of the dimethylamino group

Abram, U.; Mack, J.; Ortner, K.; Müller, M.

  • J. Chem. Soc. Dalton Trans. 1998, Pages 1011-1019

Publ.-Id: 1151

Synthesis, Characterization and Structure of bis{2-[1-(thiosemicarbazono)ethyl]pyridinium}hexanitratothorate(IV)

Abram, U.; Abram, S.

  • J. Chem. Cryst.

Publ.-Id: 1149

A New Electrode-Mesh Tomograph for Gas-Liquid Flows

Prasser, H.-M.; Böttger, A.; Zschau, J.

The paper presents an electrode-mesh tomograph for the high-speed visualisation of transient gas fraction distributions in two-phase flows in pipes. It is based on the measurement of the local instantaneous conductivity of the two-phase mixture. The time resolution of the device is 1024 frames per second. The sensor consists of two electrode grids with 16 electrodes each. This results in 16 x 16 sensitive points, which are equally distributed over the cross section. The sensor is available in two designs: (1) wire-mesh sensor for lab applications and (2) sensor with enforced electrode rods for high mechanical loads. The device was recently tested in a vertical and a horizontal air-water flow in a pipe of 51.2 mm diameter.

  • Flow Measurement and Instrumentation 9 (1998) 111-119

Publ.-Id: 1148

Annealing and Recrystallization of Amorphous Silicon Carbide Produced by Ion Implantation

Höfgen, A.; Heera, V.; Eichhorn, F.; Skorupa, W.

  • Journal of Applied Physics Vol. 84, Number 9, 1. Nov. 1998, pp. 4769-4774
  • Lecture (Conference)
    ECSCRM '98 (2nd European Conf. on Silicon Carbide and Related Materials), Montpellier, Sept. 2 - 4, 1998

Publ.-Id: 1147

Laserspektroskopie in der Nuklearchemie- Möglichkeiten und Grenzen

Geipel, G.; Bernhard, G.; Rutsch, M.; Nitsche, H.

  • Lecture (Conference)
    Vortrag bei der Vortragstagung der Fachgruppe Nuklearchemie der GDCh, Dresden, Germany, 07.-09.09. 1998

Publ.-Id: 1146

Institute of Ion Beam Physics and Materials Research; Annual Report 1997

von Borany, J.; Jäger, H.-U.; Möller, W.; Wieser, E.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-212
    ISSN: 1436-3976


Publ.-Id: 1144

Focused Ion Beam Sputtering of Silicon and Related Materials

Bischoff, L.; Teichert, J.

The impressive development of focused ion beam (FIB) systems from the laboratory level to high performance industrial machines during the last twenty years is briefly reported. The design and the functional principle of a liquid metal ion source as well as a FIB column are described. Main application fields of the FIB technology are stoichiometric writing implantation or ion milling which are dominated by the sputtering effect. The FIB is a very suitable tool for sputtering of well defined holes which can easily be analysed by surface profiling. By applying this volume loss method the sputtering yields and milling rates of crystalline, amorphous, and poly-silicon, as well as SiO2, CVD- and high pressure (HP) - diamond and 6H:SiC were investigated for 35 and 70 keV Co, Ga, Ge, Nd and Au ions. For crystalline silicon and 6H:SiC targets, the sputtering yield was determined as a function of the incident angle of the ions and the substrate temperature. In addition, the influence of the pixel dwell time on the erosion process in the case of high dose cobalt implantation was investigated. The experimental obtained yield data are compared with calculated values using different known models.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-217
    ISSN: 1436-3976


Publ.-Id: 1143

Qualifizierung des Kernmodells DYN3D im Komplex mit dem Störfallcode ATHLET als fortgeschrittenes Werkzeug für die Störfallanalyse von WWER-Reaktoren, Abschlußbericht Teil 1

Grundmann, U.; Kliem, S.; Krepper, E.; Mittag, S.; Rohde, U.; Schäfer, F.; Seidel, A.

Das Reaktorkernmodell DYN3D mit 3D Neutronenkinetik wurde an den Thermohydraulik-Systemcode ATHLET angekoppelt. Im vorliegenden Bericht werden Arbeiten zur Qualifizierung des gekoppelten Codekomplexes zu einem validierten Hilfsmittel für Störfallablaufanalysen zu Reaktoren des russischen Typs WWER dargestellt. Diese umfaßten im einzelnen:
  • Beiträge zur Validierung der Einzelcodes ATHLET und DYN3D anhand der Nachrechnung von Experimenten zum Naturumlaufverhalten an thermohydraulischen Versuchsanlagen und der Lösung von Benchmarkaufgaben zu reaktivitätsinduzierten Transienten,
  • Akquisition und Aufbereitung von Meßdaten zu Transienten aus Kernkraftwerken, Validierung von ATHLET-DYN3D anhand der Nachrechnung eines Störfalls mit verzögerter Schnellabschaltung und einer Pumpentransiente in WWER-Reaktoren,
  • eine ergänzende Weiterentwicklung von DYN3D durch Erweiterung der neutronenphysikalischen Datenbasis, Einbau eines verbesserten Modells für die Kühlmittelvermischung, Berücksichtigung der Nachzerfallswärme, Berechnung von Xenon- Oszillationen,
  • Analyse von Frischdampfleckszenarien für eine WWER-440-Anlage mit Annahme des Versagens verschiedener Sicherheitseinrichtungen, Untersuchung verschiedener Modelloptionen. Die Analyse ergab eine mögliche Rekritikalität des abgeschalteten Reaktors bei realistischer Modellierung der Kühlmittelvermischung im Ringspalt und unteren Plenum.
Mit der Anwendung des Programmpakets ATHLET-DYN3D in Tschechien, Bulgarien und der Ukraine wurde bereits begonnen. Weiterführende Arbeiten beinhalten die Verifikation von ATHLET-DYN3D mit einer DYN3D-Version für die quadratische Brennelementgeometrie westlicher Druckwasserreaktoren.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-216
    ISSN: 1436-3976


Publ.-Id: 1142

Praktische Anwendungen der Ionenimplantation

Möller, W.; Richter, E.

  • Galvanotechnik Heft Nr. 3, Band 89 (1998) 858

Publ.-Id: 1140

Modification of Titanium by Ion Implantation of Calcium and/or Phosphorus

Wieser, E.; Tsyganov, I.; Matz, W.; Reuther, H.; Oswald, S.; Pham, M. T.; Richter, E.

  • Surface & Coatings Technology 111 (1999) 103-109

Publ.-Id: 1138

Analyses of the NOKO Emergency Condenser Experiments

Dumaz, P.; Schaffrath, A.

In the frame of the so-called BWR-CA concerted action of the European Union, one has to analyse some experiments performed on the NOKO facility using the CATHARE2 (CEA) and the ATHLET (FZR) thermalhydraulic codes. These calculations have shown that both CATHARE and ATHLET are able to predict the global performance of the NOKO emergency condenser. In reference calculations, the unrelevance of the Shah correlation used in CATHARE was not seen apart from the BLIND case. Taking into account the sensitivity calculations, it is thought that this problem is due to an overestimation of the liquid film velocity. This latter can be considered as a consequence of a wrong estimation of the film entrainment onset or as a limitation of the two-phase six-equation model (only one average liquid velocity). Further verification and qualification of computer codes require the analysis of tests with a better instrumentation. Measurements of local parameters like the inside tube temperature or the distribution of pressure losses, are really necessary to undertake this work. It is why it has been proposed, in the frame of a new concerted action, to use the NOKO single tube experiments already performed by FZJ and which are much better instrumented in comparison of the just considered bundle tests.

Keywords: ATHLET; CATHARE; condensation inside horizontal tubes

  • Lecture (Conference)
    Seminaire Systemes REP No. 2, Cadarache 19. März 1998

Publ.-Id: 1137

Uran LIII EXAFS Messungen zur Untersuchung der Uranyl-Adsorption an Ferrihydrit

Hennig, C.; Arnold, T.; Roßberg, A.; Reich, T.; Nitsche, H.

  • Poster
    GDCh-Fachgruppentagung Nuklearchemie, Dresden, Germany, 07.-09.09.1998

Publ.-Id: 1136

Post-Test Calculations of NOKO Emergency Condenser Experiments

Schaffrath, A.; Dumaz, P.

The SWR1000 is a new innovative boiling water reactor concept,
which is developed by Siemens AG. This concept is characterized
in particular by passive safety systems (e.g., four emergency
condensers, four building condensers, eight passive pressure
pulse transmitters, six gravitydriven core flooding lines).
Passive safety systems need no external energy sources. The
function is directly based on the physical phenomena:
gravity, natural convection and/or evaporation. Therefore the
effectiveness is independent of operator actions and smaller
failure rates are assigned to passive safety systems.
For the experimental investigation of the operation mode and
the effectiveness of these passive safety systems the multipurpose
thermohydraulic test facility NOKO (NOKO is an abbreviation for
the German translation of emergency condenser) was constructed
at the Forschungszentrum Jülich (FZJ). The facility has a maximum
power of 4 MW for steam production and a maximum operating pressure
of 10 MPa.

In the frame of an European Union programme (EU BWR R&D Cluster),
six test series with an emergency condenser test bundle were
performed in 1996. Within the Physics and Thermalhydraulics
Complementary Actions (BWR/CA) to the EU BWR R&D Cluster the
German Forschungszentrum Rossendorf (FZR) e.V. and the French
Commisariat a'l Energie Atomique (CEA/DRN) have calculated 9 tests
and an additional blind test of the NOKO bundle experiments. These
posttest calculations were carried out using ATHLET (FZR) and
CATHARE2 (CEA/DRN). The results of these calculations are presented
in this paper.

Detailed comparisons of ATHLET and CATHARE results show that despite
the good prediction of global parameters for both codes, the variations
of local parameters calculated (e.g., film velocity and temperature)
are not in such a good agreement. This can be explained by some
compensating errors in computer codes (e.g., an overestimation of
the condensing film velocity can hide an error in the condensation
correlation) and the significant effect of the tube wall conduction
in controlling the heat transfer. The emergency condenser test bundle
of the available and considered experiments were not instrumented.
Therefore a deeper analysis (including a detailed comparison of local
parameters) is not possible. New test series released in the frame of
a new European union action will be analyzed in 1998.

  • Lecture (Conference)
    ICONE 6 - 6th International Conference on Nuclear Engineering , 10.-14. Juni 1998, San Diego, Californien, Beitrag 6382
  • Contribution to proceedings
    ICONE 6 - 6th International Conference on Nuclear Engineering , 10.-14. Juni 1998, San Diego, Californien, Beitrag 6382

Publ.-Id: 1135

Thioether Ligands as Anchor Group for Coupling the "Tc(CO)3" and "Re(CO)3" Moieties with Biologically Active Molecules

Pietzsch, H.-J.; Reisgys, M.; Alberto, R.; Abram, U.; Hoepping, A.; Scheunemann, M.; Seifert, S.; Wüst, F.; Spies, H.; Schubiger, P.; Johannsen, B.

  • Lecture (Conference)
    33. ICCC Florenz, September 1998

Publ.-Id: 1134

Pre- and Posttest Calculations to Natural Circulation Experiments at the Integral Test Facility ISB-VVER Using the Thermalhydraulic Code ATHLET

Krepper, E.

In 1995 at the integral test facility ISB-VVER in Elektrogorsk near Moscow natural circulation experiments were performed, which were scientifically accompanied by the Forschungszentrum Rossendorf. These experiments were the first of this kind at a test facility, which models VVER-1000 thermalhydraulics. Using the code ATHLET which is being developed by "Gesellschaft für Anlagen- und Reaktorsicherheit", pre- and posttest calculations were done to determine the thermalhydraulic events to be expected and to define and tune the boundary conditions of the test. The conditions found for natural circulation instabilities and cold leg loop seal clearing could be confirmed by the tests. Besides the thermalhydraulic standard measuring system, the facility was equipped with needle shaped conductivity probes for measuring the local void fractions.

  • Nuclear Engineering and Design 190(1999)341-346

Publ.-Id: 1132

Reactions of Dichloro[2-(dimethylaminomethyl)phenyl-C1,N]gold(III), [Au(damp-C1,N)Cl2], with aromatic thiosemicarbazones. Structures and Spectroscopical Data of the First Gold(III) Thiosemicarbazone Complexes

Ortner, K.; Abram, U.

  • Inorganic Chemistry Communications 1 (1998) 251-253

Publ.-Id: 1131

The Application of Decision Analysis in the Remediation Sector

Kruber, S.; Schöne, H.

Abstract Contaminated sites represent a serious environmental problem in Germany. The decision that remediation technology is optimal for a given site is complicated by the existence of multiple objectives to be optimized simultaneously, significant uncertainties about the remediation results, and the involvement of several decision-makers with conflicting interests. Decision analysis is a methodology to deal with problems of this kind. The application of decision analysis at a test site demonstrated that remediation decisions can greatly benefit from the structural guide, sound methodological approaches, and manifold results that can be deduced from decision analytic models. The careful preparation of the decision helps to prevent momentous wrong decisions, especially due to the sophisticated support, that decision analysis offers for risky decisions. Because remediation decisions can be regarded as prototypical for many decisions in the public sector, the results of this study may also impact other fields like waste management, water resource administration, traffic planning, or siting of hazardous industrial facilities.

  • Environmental Engineering and Policy Vol.1 Nr.1 (7/1998) 25-35 Springer-Verlag Heidelberg, ISSN: 1433-6618

Publ.-Id: 1129

Estimates of Production Rates of SUSY Particles in Ultra-Relativistic Heavy-Ion Collisions

Beinker, M. W.; Kämpfer, B.; Soff, G.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-213
    ISSN: 1436-3976
  • Journal of Physics G 24 (1998) 1235-1248


Publ.-Id: 1128

Untersuchung der Bildung der Eisensilizide während der Ionenstrahlsynthese und der ionenstrahlinduzierten Phasenbildung

Dobler, M.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-214; TU Dresden, 23. 01. 1998
    ISSN: 1436-3976


Publ.-Id: 1127

Solitonische Feldkonfigurationen des Nambu & Jona-Lasinio-Modells im Medium

Schleif, M.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-211
    ISSN: 1436-3976


Publ.-Id: 1126

Kühlmittelvermischung in Druckwasserreaktoren; Vergleich von Kühlmittelströmung und -vermischung in einem skalierten Modell des DWR Konvoi mit den Vorgängen im Originalreaktor; Rechnungen mit dem CFD-Code CFX 4.1

Höhne, T.

Es ergab sich die Notwendigkeit, die Vermischungseffekte mit einem 1:5 skalierten Modell nachzuvollziehen. In dieser Arbeit wurden Skalierungseffekte hervorgehoben und ein Vergleich der Strömungen im Originalreaktor und 1:5 Plexiglasmodell mit Hilfe eines numerischen Strömungsberechnungsprogrammes vollzogen. Dabei wurde das Modell und der Originalreaktor möglichtst originalgetreu abgebildet und mit den kalten Strängen zusammen modelliert.Die Vergleichsrechnungen belegen, daß es ausreichend ist, die Vermischungsvorgänge in einem mindestens 1:6.6 skalierten Modell eines DWR zu untersuchen. Die Parameter (Druck, Temperatur, Geschwindigkeit) erlauben den Aufbau als Plexiglasmodell, das eine optische Beobachtung der Vermischung ermöglicht. Das Forschungszentrum Rossendorf hat mit dem Aufbau eines 1:5 Modells 1997 begonnen.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-210 September 1997
    ISSN: 1436-3976


Publ.-Id: 1125

Utilization of Plasma Source Ion Implantation for Tribological Applications

Günzel, R.; Brutscher, J.; Mändl, S.; Möller, W.

  • Surface & Coatings Technology 96 (1997) pp. 16-21

Publ.-Id: 1124

Synthesis and Crystal Structure of Novel Tetrameric Nitrido Complexes

Griffith, D. V.; Parrott, J.; Togrou, M.; Dilworth, J. R.; Zheng, Y.; Ritter, S.; Abram, U.

  • Zeitschrift für anorganische und allgemeine Chemie 624 (1998) 1409-1414

Publ.-Id: 1123

Particle emission from UV-irradiated silica surfaces

Rettig, D.; Merker, P.; Nitsche, H.

  • Journal of Aerosol Science Vol.29, Suppl.1, pp. S921-S922 (1998)
  • Lecture (Conference)
    5th International Aerosol Conference, Edinburgh, 12-18.Sept.,1998

Publ.-Id: 1122

Determination of Molecular-Level Structural Information of Uranium in Environmentally Relevant Samples by EXAFS

Roßberg, A.; Denecke, M. A.; Reich, T.; Hennig, C.; Nitsche, H.

  • Poster
    Konferenz Uran-Bergbau und Hydrogeologie II, Freiberg, Germany, 15.-17.09.1998
  • Poster
    Euroconference and NEA Workshop: Actinide-XAS-98, Grenoble, France, 04.-06.10.1998

Publ.-Id: 1120

Operation Conditions of the Emergency Condenser of the SWR1000

Schaffrath, A.; Hicken, E. F.; Jaegers, H.; Prasser, H.-M.

The Siemens AG is developing the innovative boiling water reactor concept SWR1000. New features are the passive safety systems (e.g. emergency condensers, building condensers, passive pressure pulse transmitters).

For the experimental investigation of the emergency condenser effectiveness, the NOKO test facility has been constructed at the Forschungszentrum Jülich. The facility has an operating pressure of 10 MPa and a maxi-mum power of 4 MW. 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 capacity 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.

For the evaluation of the NOKO experiments, the program system CASH-Graphics (Computergestützte Auswertung und Unsicherheitsanalyse) was developed. This evaluation is the basis for the determination of the operation conditions of the emergency condenser.

Post test calculations of NOKO experiments were per-formed with an improved version of ATHLET. To calculate the heat transfer coefficients during condensation in horizontal tubes the module KONWAR has been developed and implemented in ATHLET. KONWAR is based on the flow regime map of Tandon and includes several semi-empirical correlations for the determination of the heat transfer coefficients. The comparison between calculations and experiments shows a good agreement.

Keywords: SWR1000; ATHLET; emergency condenser; KONWAR; operation conditions

  • Nuclear Engineering and Design 188 (1999), p. 303-318

Publ.-Id: 1119

Ein modernes technisches System zur verbesserten betrieblichen Überwachung des ukrainischen Kernkraftwerks Saporoshje

Beyer, M.; Carl, H.; Schumann, P.; Seidel, A.; Weiß, F.-P.; Zschau, J.; Nowak, K.

Die zu Beginn der neunziger Jahre in der Ukraine praktizierte KKW-Überwachung ermöglichte der Aufsichtsbehörde nur einen unzureichenden Zugang zu Informationen über den jeweils aktuellen betrieblichen Sicherheitszustand. Im Zusammenhang mit den Ergebnissen von Sicherheitsanalysen für Kernkraftwerke war es daher erforderlich, die Möglichkeiten der betrieblichen Überwachung dieser KKW durch die ukrainische Behörde zu verbessern. Für das KKW Saporoshje wurde vom Forschungszentrum Rossendorf im Verbund mit dem TÜV Rheinland ein modernes Überwachungssystem als Pilotprojekt konzipiert, eingerichtet und Ende 1995 in den Probebetrieb überführt. Es ergänzt die vorhandenen betrieblichen Kontroll- und Überwachungseinrichtungen durch Einbeziehung moderner Informations- und Rechentechnik. Das System ermöglicht eine kontinuierliche Beobachtung des Zustandes der Anlage im Normalbetrieb und bei Betriebsstörungen bzw. Störfällen, so daß bei erkennbaren Abweichungen vom bestimmungsgemäßen Betrieb frühzeitig durch Anfrage und Anordnung darauf reagiert werden kann.

  • Atomwirtschaft Atomtechnik 4 April 1998, S. 230-234

Publ.-Id: 1118

Einfluß von Grubenholzabbauprodukten auf die Redoxsituation in Flutungswässern und auf das Sorptionsverhältnis von Eisen und Uran an Erzgebirgsmetamorphiten und Elbtalsedimenten

Abraham, A.; Mack, B.; Antje, B.; Nitsche, H.

Die Untersuchungen zur Sorption von Eisen und Uran unter Wahrung von Grubenbedingungen bezüglich Wasserbeschaffenheit und pH-Wert wurden an typischen Gesteinen und Mineralien des Westerzgebirges wie Phyllit, Granit, Gneis, Diabas und Calcit sowie an den Königsteiner Elbtalsedimenten Sandstein, Tonstein, Pläner und Pläneräquivalent durchgeführt. Dabei wurde die Sorption unter aeroben und anaeroben Bedingungen verglichen.

Neben hydrogeochemischen Prozessen, wie z.B. der Pyritoxidation, trägt auch das Holzinventar in den Gruben und die in der Wechselwirkung mit dem Grubenwasser entstehenden Holzabbauprodukte zur Sauerstoffzehrung und damit zur Veränderung der Redoxsituation bei. Es werden reduzierende Bedingungen bezüglich Eisen(III) und Uran(VI) ausgelöst. Mittels elektrochemischer und spektrophotometrischer Methoden wurden Prozesse der Eisen(III)- und Uran(VI)-Reduktion in Langzeituntersuchungen charakterisiert.

In die Untersuchungen wurden hydrothermale Grubenholzauszüge und Fichtenholzlignine, die im Institut für Pflanzen- und Holzchemie, Tharandt präpariert wurden, einbezogen [1]. Die Sorptionsuntersuchungen an den Erzgebirgsmetamorphiten wurden aus den typischen neutralen, calcitgesättigten und sulfatreichen Gruben- und Flutungswässern, wie sie im Schlemaer Revier auftreten, vorgenommen. Im Falle der Königsteinsedimente wurde eine Wasserzusammensetzung gewählt, wie sie im Flutungsendstadium der Grube zu erwarten wäre, d.h. nach Auffüllung der in den gelaugten Sedimenten verbliebenen Lösungsrückstände mit Grundwasser [2].

Die Verteilungsverhältnisse wurden in grubenrelevanten Konzentrationsbereichen mittels batch-Technik unter Einsatz von Radiotracern (44,6 d 59Fe; 2,45∙105 a 234U) und der Flüssigszintillationsmessung bestimmt.

  • Poster
    International Conference and Workshop on Uranium Mining and Hydrogeology II, Freiberg, Germany, September 15-17, 1998

Publ.-Id: 1117

Hydrothermal Wood Decomposition and Influence of the Degradation Products on the Uranium Adsorption on Metamorphic Rocks and Sediments

Baraniak, L.; Jelen, K.; Schiene, R.; Fischer, K.; Bernhard, G.; Nitsche, H.

The influence of mine-wood leachates on the uranium(VI) adsorption (1) on typical rocks and minerals of the ore mountains mining sites and (2) on sediments of the Königstein mine (Saxony) and its near field was studied under aerobic condition.

Wood decomposition was carried out by boiling of shavings with water under reflux. The leachate were analysed regarding DOC, phenolic and saccharic compounds, molecular weight distribution and content of carboxylic and phenolic hydroxyl groups.

The adsorption experiments were carried out by a 4-6 weeks equilibration of the geomaterial with the aqueous phase in the presence of U(VI) and DOC. The uranium concentration ranged from 3.2∙10-6 to 3.2∙10-5 mol/L (0.76-7.62 mg/L) and the DOC content was 8.3-166 mg/L. The distribution ratio (Rs [mL/g]) was determined from liquid scintillation counting of the added 234U tracer (10-40 Bq/sample) after distribution and a careful phase separation.

Uranium adsorption behaviour at the ore mountains rocks and minerals: The adsorption from a DOC-free synthetic mine water takes mainly place at diabase (Rs=4.8 mL/g) and calcite (Rs=4.5); about 80% of the uranium is bound on this minerals. The adsorption under the influence of the wood degradation products and pine wood lignin (PWL) is increased to 90-95 % (calcite: Rs=13.0/108 mL/g; diabase: Rs= 9.9/59). Granite and basalt adsorb from DOC-free mine water 50-60% of the uranium (Rs=0.97/1.6). In the presence of the wood leachate and lignin the adsorption increases to about 80% (granite: Rs=6.5/15.5; basalt: Rs=5.9/18.5). In the case of gneiss the effect of the wood leachate and lignin is not so significant (Rs: 1.1-1.5). The uranium adsorption on phyllite takes place to a much lower level. From all solutions practically no uranium is bound (Rs≤ 0.1), i.e., uranium adsorption is smaller than 2%.

Uranium adsorption behavior at the Königstein sediments: It is evident that uranium is prefferently bound to sandstone (91-97%); especially with a high distribution ratio to the limonithe-rich turonian sandstone (142 mL/g). Even under the influence of the organic compounds the sorption ranges from 68 to 93% (Rs: 10-70). A sorption degrease is caused by the wood leachate and lignin (2-4%). The level of adsorption on lime marl is much lower (22-68%, Rs: 1.4-11). The wood leachate and the lignin enhance the adsorption by 10-20%. The studied claystone, in general, was not able to bind uranium. Only in the presence of the wood leachate about one third of the uranium is adsorbed (Rs= 2.9). The reason may be that this sediment acidifies the aqueous phase (from pH 7.3 to 3.5) and some of the DOC with part of the uranium is precipitated on the sediment.

As a general tendency it can be seen that the strongly polymer wood breakdown substances strengthen the uranium(VI) adsorption at the geomaterials from the typical mine waters.

  • Poster
    International Conference and Workshop on Uranium Mining and Hydrogeology II, Freiberg, Germany, September 15-17, 1998

Publ.-Id: 1116

Speziation des Urans- Bestimmung und Berechnung unter natürlichen Bedingungen

Geipel, G.; Rutsch, M.; Bernhard, G.; Brendler, V.; Nitsche, H.

  • Lecture (Conference)
    Uran Konferenz Freiberg 1998

Publ.-Id: 1115

Coupling Geochemical Speciation to Risk Assessment Codes

Brendler, V.; Bernhard, G.; Nitsche, H.; Stiglund, Y.; Nordliner, S.

  • Poster
    Konferenz "Uran-Bergbau und Hydrogeologie II", Freiberg, 15.-17. September 1998

Publ.-Id: 1114

Spatial Distribution of Defects in Ion-Implanted and Annealed Si: the RP/2 Effect

Kögler, R.; Yankov, R. A.; Kaschny, J. R.; Posselt, M.; Danilin, A. B.; Skorupa, W.

  • Nuclear Instruments and Methods in Physics Research B 142 (1998) 493-502

Publ.-Id: 1113

Post Test Calculations to 11% Break LOCA Experiments at the Integral Test Facility ISB-VVER Using the Thermohydraulic Code ATHLET

Krepper, E.

The considered test was a break on the upper plenum with different modes of emergency core cooling. The reference case was the non-availability of emergency cooling. Injecting the emergency coolant into the cold leg, no increasing of rod cladding temperatures was observed, but natural circulation instabilities occurred. Injecting the cooling into the hot leg, the cooling situation was getting worse. Due to the injected cold emergency coolant, the fluid density in the discharge volume was enhanced and the break mass flow increased. The observed events in the test were reproduced by the code with good agreement

  • Nuclear Engineering and Design 170 (1997) pp. 3-7

Publ.-Id: 1112

Post Test Calculations for a Small Break LOCA Experiment at the Integral Test Facility ISB-VVER Using the Thermalhydraulic Code ATHLET

Krepper, E.

The ISB-VVER facility of the Elektrogorsk Research and Engineering Center is currently the only operating integral test facility for the thermal hydraulic behaviour of the Russian pressurized water reactor VVER-1000. In 1993 it was decided, to perform a test for a small break at the upper plenum with locked rotor of all circulating pumps as the 1st Russian Standard Problem. The experimental results were made available to the Research Center Rossendorf, where post test calculations were carried out using the GRS-code ATHLET. The main results of these calculations are presented in this paper.

  • Lecture (Conference)
    Jahrestagung Kerntechnik Mannheim 1996, Proceedings pp. 122-125
  • Contribution to proceedings
    Jahrestagung Kerntechnik Mannheim 1996, Proceedings pp. 122-125

Publ.-Id: 1111

Thermal Dilepton Signal Versus Dileptons from Open Charm and Bottom Decays in Heavy-Ion Collisions

Gallmeister, K.; Kämpfer, B.; Pavlenko, O. P.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-209
    ISSN: 1436-3976
  • Physical Review C, Vol. 57 (1998) pp. 3276-3283


Publ.-Id: 1110

A Mixed-Ligand P,S,N-cis-Dioxorhenium(V) Complex by Ligand Exchange Reaction on trans-monooxo-trichloro-bis(triphenylphosphine)rhenium(V): Formation and Structural Studies

Friebe, M.; Jankowsky, R.; Spies, H.; Seichter, W.; Papadopoulos, M.; Chiotillis, E.; Johannsen, B.

  • Polyhedron Vol. 17, No. 21, pp. 3711-3720, 1998

Publ.-Id: 1109

Damage in silicon carbide induced by Rutherford backscattering analysis

Fukarek, W.; Yankov, R. A.; Anwand, W.; Heera, V.

  • Nuclear Instruments and Methods in Physics Research B135-138 (1998) 460

Publ.-Id: 1108

Dependence of the Silicon Detector Response to Heavy Ions on the Direction of Incidence: Computer Simulations Versus Experimental Data

Pilz, W.; von Borany, J.; Grötzschel, R.; Jiang, W.; Posselt, M.; Schmidt, B.

  • Nuclear Instruments and Methods in Physics Research A 419 (1998) 137-145

Publ.-Id: 1107

A Parallel Code for Kinetic 3D Lattice MC Simulations of Nucleation, Growth and Ostwald Ripening of Nanocrystals

Schmeißer, N.; Kunicke, M.; Heinig, K.-H.

The continuing exponential increase in computer power together with the recent developments of very efficient numerical procedures allow nowadays to perform predictive atomic-scale computer simulations for material science. This holds especially for advanced microelectronic devices where functional units consists more and more often of 10^6 atoms or even less. In this situation the design of new materials and devices is more and more frequently supported by atomic-scale computer simulations.

A kinetic 3D Monte-Carlo code based on stochastic probabilistic two-center cellular automaton using a double bookkeeping technique, one in the particle vector and the other in the lattice space was originally coded in PASCAL and tested on an INTEL PC, later in C and on HP workstations. This implementation should be speeded up considerably in order to undertake real scientific simulations. The only way to get the needed speedup is parallelisation.

We started with a look at the given sequential code, translated it into C and run it on our S-Class Server. While translating we had to understand a lot of things, e.g. the double booking technique, so that we could do first steps of scalar optimisation during this process.

The most simple idea of a parallel approach is distributing the lattice across the processors. But because of the physical problem modelling the growth of clusters of implanted particles in the lattice such an approach will lead to load imbalances and destroy the effect of parallelisation.

With an another approach we tried to distribute the work done in the particle space instead of the lattice space. We developed a graph-theoretical approach based on skeletons to find out a work distribution across 2^n processors that assure s a good load-balance. The disadvantage of this approach is the work needed to compute the distribution which is of order O(n^3) compared to the simulation which is of order O(n).

At this point it turned out the given model was not suitable for parallelising the algorithm. So we had feed-back with the physicist and together we developed a model of the physical process where the algorithm which solves the problem could be formulated in parallel. The new model allowed us to divide the solution into three main steps, where two of them can be done parallel and will therefor improve the speed of the algorithm.

We implemented this algorithm in a mixed language modularised program using FORTRAN for the computational part and C for the I/O part. The program runs on our S-Class server using maximum 8 processors.

In our presentation the methodology of creating an optimised parallel code for the Monte-Carlo simulation of Ostwald Ripening, the schema of the parallel code and first real physical simulation results will be shown.

  • Lecture (Conference)
    The 13th Annual HPC User Group Conference 1998

Publ.-Id: 1106

No Carrier Added Preparations of '3+1' Mixed-Ligand 99mTc Complexes

Seifert, S.; Pietzsch, H.-J.; Scheunemann, M.; Spies, H.; Syhre, R.; Johannsen, B.

  • Appl. Radiat. Isot. Vol. 49, Nos 1-2, pp. 5-11, 1998

Publ.-Id: 1105

Differentiation Between Specific and Nonspecific Effects Related to P-Glycoprotein Inhibition in Immortalized Rat Brain Endothelial Cells

Bergmann, R.; Brust, P.; Johannsen, B.

  • International Journal of Clinical Pharmacology and Therapeutics, Vol. 36, No. 1, 1998 (46-49)

Publ.-Id: 1104

Computer Simulation of Ion-Assisted Thin Film Deposition

Möller, W.

  • Radiation Effects and Defects in Solids, Vol. 141, pp. 73-81

Publ.-Id: 1103

Computer Simulation of Precipitate Coarsening: A Unified Treatment of Diffusion and Reaction Controlled Ostwald Ripening

Strobel, M.; Reiss, S.; Heinig, K.-H.; Möller, W.

In Ion Beam Synthesis (IBS) of nanoclusters the postimplantation
annealing step causes major redistribution of the implanted impurity atoms
by Ostwald ripening (OR). The diffusion-reaction equations describing OR
are highly nonlinear. Therefore, analytical studies are restricted to special
cases like the asymptotic behaviour, the diffusion or reaction controlled
limit, low cluster concentration, etc. An alternative to analytical studies
of OR is the numerical integration of the diffusion-reaction equations.
Using this method we take into account the diffusion and reaction control
of OR, i.e. we present for the first time an unified treatment for the
whole range of and in between the diffusion and reaction controlled limits.
Based on a local mean field theory, our model starts with a multipole expansion
of the concentration field, which satisfies the stationary diffusion equation.
Using appropriate boundary conditions on the precipitates we derive self-consistently
the governing equations for the evolution of the clusters. Alternatively
to Ewald's summation method we apply a Yukawa-like screening of precipitates.
The dependence of the particle radius distribution (PRD) the critical radius
and the density of nanoclusters on process parameters will be discussed.

  • Rad. Eff. Def. Sol. 142 (1997) 99

Publ.-Id: 1102

Comparison of YAP and BGO for high resolution PET detectors.

Kapusta, M.; Pawelke, J.; Moszynski, M.

The goal of this work was to evaluate the potential of small YAP:Ce crystals, especially designed for a high-resolution PET system. We directly compared the scintillator properties of 3x3x20 mm3 crystals YAP with those of BGO. The light output, energy resolution, detection efficiency and timing properties for the irradiation using 137Cs and 22Na sources were investigated. Special consideration was given to the influence of the reflector coating on the light output as well as on the overall performance of the quality of the studied crystals.

  • Nuclear Instruments and Methods in Physics Research A 404 (1998) 413-417

Publ.-Id: 1101

Thermodynamics of the PHI4 Theory in Tadpole Approximation

Peshier, A.; Kämpfer, B.; Pavlenko, O. P.; Soff, G.

Relying on the Luttinger-Ward theorem we derive a thermodynamically selfconsistent and scale independent approximation of the thermodynamic potential for the scalar Φ4 theory in the tadpole approximation. The resulting thermodynamic potential as a function of the temperature is similar to the one of the recently proposed screened perturbation theory.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-208
    ISSN: 1436-3976
  • Europhysics Letters 43 (4), pp. 381-385 (1998)


Publ.-Id: 1099

Modifizierung der tribologischen, mechanischen und korrosiven Eigenschaften von Siliziumnitrid-Keramik mittels Ionenimplantation

Brenscheidt, F.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-207, Dissertation; TU Dresden, Dez. 1997
    ISSN: 1436-3976


Publ.-Id: 1098

States of Seniority 3 and 5 in the N=48 Nucleus 87Y

Schwengner, R.; Reif, J.; Schnare, H.; Winter, G.; Servene, T.; Käubler, L.; Prade, H.; Wilhelm, M.; Fitzler, A.; Kasemann, S.; Radermacher, E.; von Brentano, P.

  • Physical Review C Volume 57, Number 6, pp. 2892-2902

Publ.-Id: 1096

Stability versus Reactivity of "3+1" Mixed-Ligand Technetium-99m Complexes in Vitro and in Vivo

Syhre, R.; Seifert, S.; Spies, H.; Gupta, A.; Johannsen, B.

  • Europ. Journal of Nuclear Medicine,Vol. 25, No. 7, July 1998, 793-796

Publ.-Id: 1095

Gasgehaltsmessung mit nadelförmigen Leitfähigkeitssonden in schäumenden Medien

Kern, T.

  • Poster
    DECHEMA Jahrestagung 1998
  • Contribution to proceedings
    DECHEMA Jahrestagung 1998, Fachtreffen Sicherheitstechnik, Tagungsband II, S. 163-164, Wiesbaden, 26.-28. Mai 1998

Publ.-Id: 1094

Workshop "Meßtechnik für stationäre und transiente Mehrphasenströmungen" , 6.-7. November 1997 in Rossendorf

Prasser, H.-M.; (Editor)

  • Open Access Logo Forschungszentrum Rossendorf; FZR-204, Dezember 1997 (Tagungsband)
    ISSN: 1436-3976


Publ.-Id: 1093

Institute of Bioinorganic and Radiopharmaceutical Chemistry; Annual Report 1997

Johannsen, B.; Seifert, S.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-200
    ISSN: 1436-3976


Publ.-Id: 1092

Measurement and Simulation of the Turbulent Dispersion of a Radioactive Tracer in a Two-Phase Flow System

Hensel, F.; Rohde, U.

Studies on the measurement of turbulent dispersion of a radiotracer in an experimental setup with natural convection liquid-gaseous flow were carried out at the Forschungszentrum Rossendorf. Liquid-gaseous bubbly flow was generated in a narrow tank by injection of pressurized air into water or by catalytic disintegration of H2O2. A small amount of a positron emitting radiotracer liquid ( 18F in an aqueous NaF solution) was injected instantaneously at a certain point of the tank. The Positron Emission Tomography (PET) technique was used to observe the spreading of the tracer liquid in the bubbly flow. A double head gamma detector array was used for measuring the positron annihilation rate which is proportional to the tracer concentration. The dispersion coefficient D for the tracer liquid was calculated from the experimental data assuming an isotropic spreading of the concentration profile after separation of the linear displacement of the maximum concentration point. Calculations of the two-phase flow with spreading tracer were carried out for selected experiments using the computational fluid dynamics code CFX-4. The Euler-Euler continuum approach including a homogeneous low Reynolds number K,? -model was applied for the two-phase flow. Turbulent Prandtl numbers for gas and tracer dispersion were varied. In case of higher gas injection rates into water (superficial gas velocities jgas of 5 - 15 mm/s), a reasonable agreement was achieved between calculated and measured values of the tracer transport velocity and the dispersion coefficient. A nearly linear correlation between jgas and D was found in agreement with other authors. However, it was necessary to take into account the significant deviation of the tracer distribution from the ideal diffusion equation solution in some cases, in particular if the tracer has been spread over upwards and downwards regions of the natural circulation velocity field. Further investigations are necessary to improve the agreement between measured and calculated values of the dispersion coefficient and tracer transport velocity in the case of H2O2 disintegration and low gas superficial velocities.

  • Contribution to external collection
    M. Rahman, C. A. Brebbia, G. Comini (Hrsg.) Advances in Fluid Mechanics II, Southampton 1998, ISBN 1-853-12589-X, p. 283
  • Lecture (Conference)
    Advances in Fluid Mechanics II (AFM98). Udine (Italy) May 13-15, 1998

Publ.-Id: 1091

Einfluß von Zusätzen niedermolekularer oberflächenaktiver Stoffe auf den Massenaustrag bei der Druckentlastung eines verdampfenden Stoffsystems

Lucas, D.; Prasser, H.-M.; Kern, T.

Das Schaumverhalten eines Stoffsystems bei Druckentlastungsvorgängen hat einen wesentlichen Einfluß auf die Druckabfallgeschwindigkeit und die ausgetragene Masse. Es wurden kleinmaßstäbliche Druckentlastungsversuche mit einem 1,9 l Gefäß durchgeführt. Das Abblasen erfolgte über eine kopfseitige Abblaseleitung mit einer Blende. Unter sonst gleichen Bedingungen wurde reines Wasser und Wasser mit Zusatz von Isobutanol abgeblasen. Gemessen wurden der Behälterdruck, die ausgetragene Masse, sowie Temperaturen und Dampfgehalte an jeweils 2 verschiedenen Höhenpositionen. Es wurden Experimente mit einem Blendendurchmesser von 2 mm und 3 mm sowie Isobutanolzusätzen von 2, 4 und 6 Gew.% durchgeführt. Für beide Abblasequerschnitte zeigte sich eine deutliche Zunahme der ausgetragenen Masse mit der Isobutanolkonzentration. Auf Grund der Schaumbildung und des dadurch vergrößerten Flüssigkeitsaustrags wird der Druckabbau zu Beginn des Druckentlastungsvorgangs behindert. Löst sich schließlich die Oberkante der Schaumschicht vom Deckel, erfolgt der Druckabbau auf Grund der dann geringeren Masse im Behälter schneller.

  • Lecture (Conference)
    GVC-Fachausschuß-Sitzung "Mehrphasenströmungen", 2.-6. März 1998, Aachen

Publ.-Id: 1090

Einfluß der Abblaseleitung auf die Notentspannung von Reaktoren

Lucas, D.; Prasser, H.-M.

Die Einrichtung zur Druckentlastung (Sicherheitsventil, Berstscheibe) ist in der Praxis über eine mehr oder weniger lange Abblaseleitung mit dem Reaktor verbunden. Bei der Auslegung der Sicherheitseinrichtung wird jedoch lediglich der notwendige Ausströmquerschnitt ermittelt. Berücksichtigt wird dabei gegebenenfalls der Druckverlust in der Leitung. Die Auswirkungen auf die Dynamik des Druckentlastungsvorgangs während des zweiphasigen Ausströmens bleiben bisher weitgehend unbeachtet. Aus diesem Grund wurden verschiedene Modelle für die Simulation des gekoppelten Systems bestehend aus Druckbehälter, Abblaseleitung und Entlastungsarmatur aufgestellt. Dabei wurden mehrere Varianten von vereinfachten Leitungsmodellen untersucht. Zur Überprüfung der Modellgüte wurden dabei Ergebnisse von Experimenten genutzt, die an der Druckhalterversuchsanlage DHVA der Hochschule für Technik, Wirtschaft und Sozialwesen Zittau/Görlitz durchgeführt wurden und bei denen Massenstrompulsationen bei Abblasen auftraten. Die Schwingungen hängen sehr empfindlich von einzelnen Parametern des Schaummodells, des Modells für die Kopplung zwischen Behälter und Abblaseleitung und des Modells für die Abblaseleitung ab. Experimentelle Daten zu diesen Schwingungen stellen daher eine ausgezeichnete Grundlage für die Validierung von Codes zur dynamischen Simulation eines Blow-Down Systems dar.

  • Poster
    DECHEMA-Jahrestagung '98, 26.-28. Mai 1998, Wiesbaden
  • Contribution to proceedings
    DECHEMA Jahrestagung '98, Tagungsband S. 158-159, Wiesbaden, 26. - 28.05.1998

Publ.-Id: 1089

BRICK - ein Simulationstool für Mehrphasenströmungen in Behältern auf der Basis einer Partikelmethode

Lucas, D.

Im Rahmen der Entwicklung eines Gesamtmodells für die dynamische Simulation komplexer Druckentlastungssysteme bestehend aus Reaktor, Abblaseleitung,
Entlastungsarmatur und Auffangeinrichtungen wurde ein 1-D-Behältermodell
aufgestellt. Die Transportvorgänge im Behälter werden auf der Grundlage einer
neu entwickelten Partikelmethode gelöst. Dadurch wird numerische Diffusion
vermieden, was insbesondere bei der Berücksichtigung von Diskontinuitäten, wie
z. B. dem Gemischspiegel, von Vorteil ist. Die implizite Wiedergabe der aktuellen Position des Gemischspiegels sowie ein spezielles Interface ermöglichen die
Beachtung der Entwicklung einer Schaumkrone am Übergang zwischen dem
Zweiphasengemisch und dem Gasraum. Die weitgehende Entkopplung der einzelnen
Phänomene erlaubt eine modulare Codestruktur, bei der Modelle für
Einzelphänomene leicht ausgetauscht werden können.

  • Lecture (Conference)
    GVC-Jahrestagung '98, 30.9.-2.10.1998, Freiburg
  • Chemie-Ingenieur-Technik (70) 9198 pp. 1139

Publ.-Id: 1088

The Nuclear Structure of 126Te Studied with (d,p), (d,3He) and (d,d') Reactions*

Ott, J.; Doll, C.; von Egidy, T.; Georgii, R.; Grinberg, M.; Schauer, W.; Schwengner, R.; Wirth, H.-F.

  • Nuclear Physics A 625 (1997) 598-620

Publ.-Id: 1087

Development of Segmented Ge Detectors for Future GAMMA-Ray Arrays

Eberth, J.; Thomas, H. G.; Weisshaar, D.; Becker, F.; Fiedler, B.; Skoda, S.; von Brentano, P.; Gund, C.; Palafox, L.; Reiter, P.; Schwalm, D.; Habs, D.; Servene, T.; Schwengner, R.; Schnare, H.; Schulze, W.; Prade, H.; Winter, G.; Jungclaus, A.; Lingk, C.; Teich, C.; Lieb, K. P.

The EUROBALL Cluster detector is composed of seven encapsulated Ge detectors
in a common cryostat with a total volume of 2000 ccm of HP Germanium. The
development and the performance of the Cluster detector is summarized.
Up to six Cluster detectors were used in pre-EUROBALL experiments at the
S-DALINAC Darmstadt, at the tandem-postaccelerator facility of the MPI-K
Heidelberg and the UNILAC at GSI. Examples of these experiments - the excitation
of dipole modes with (gamma, gamma')-reactions and the first coincidence
spectroscopy of the N=Z nucleus 68Se with a CLUSTER Cube - are
discussed. The development of segmented encapsulated Ge detectors for a
MINIBALL at the radioactive beam facility REX-ISOLDE has been launched.
The status of the project is presented.

  • Progr. Part. Nucl. Phys., Vol. 38, pp. 29-37, 1997

Publ.-Id: 1084

Structure of Laser-Deposited Fe/Al-Multilayers

Noetzel, J.; Geisler, H.; Gorbunov, A.; Dietsch, R.; Mai, H.; Mensch, A.; Möller, W.; Pompe, W.; Reuther, H.; Tselev, A.; Wieser, E.; Worch, H.

Fe/Al nm-period multilayers deposited by pulsed laser deposition were investigated by conversion electron Mößbauer spectroscopy and transmission electron microscopy. No Fe-Al intermetallic phases were found in the
intermixed transition range with an Al-concentration of 20-60 at.%. A qualitative depth distribution of the impurity concentration in the transition layers between subsequent Fe and Al layers is suggested.

  • Contribution to proceedings
    Proceedings of TATF 98 18.3.-20.3.1998 in Regensburg (6th International Conference on Trends and new Applications of thin Films)
  • Materials Science Forum, Vols. 287-288 (1998), pp. 455-458

Publ.-Id: 1083

Complex Formation between Uranyl and Arsenate Studied by Time-Resolved Laser-Induced Fluorescence Spectroscopy (TRLFS)

Rutsch, M.; Geipel, G.; Bernhard, G.; Nitsche, H.

  • Lecture (Conference)
    Vortrag am 18.11.1997 im National Laborstory Livermore

Publ.-Id: 1081

Laser Induced Photoacoustic Spectroscopy with OPO/FDO Systems of the Complex Formation in the System UO22+ and CO32-

Geipel, G.; Brendler, V.; Bernhard, G.; Nitsche, H.

  • Lecture (Conference)
    Vortrag am 17.11.1997 in LLNL

Publ.-Id: 1080

Laser Induced Spectroscopy at the Institute of Radiochemistry Rossendorf

Geipel, G.; Brendler, V.; Bernhard, G.; Nitsche, H.

  • Lecture (Conference)
    LANL, Actinide and Environmental Structural Chemistry, Los Alamos, New Mexico, USA, 25.11.1997

Publ.-Id: 1079

Post Test Calculations of NOKO Bundle Experiments

Schaffrath, A.

The safety concept of the new innovative boiling water reactor
SWR1000, which is developed by Siemens AG, is aiming at the
increase of safety margins and of the grace period for operator
actions during accidents by increasing the water inventory
inside the pressure vessel, by the arranging large water pools
in- (core flooding pool) and outside of the containment (dryer-
separator storage pool), simplifying the (emergency) cooling
systems and further decreasing the failure probabilities of
safety systems. Therefore, active safety systems are substituted
by passive ones or combined with passive safety systems in cases
where a replacement is not possible. The function of passive
systems is directly based on the physical phenomena: gravity,
natural convection and/or evaporation. Their effectiveness is in
dependent of operator actions. Therefore, smaller failure rates
are assigned to passive safety systems. The probability of
severe accidents of the new SWR is reduced significantly.

For the experimental investigation of the operation mode and the
effectiveness of these passive safety systems the multipurpose
thermohydraulic test facility NOKO was constructed at the
Forschungszentrum Jülich (FZJ) within a German collaboration
sponsored by the German Federal Ministry of Education, Sciences,
Research and Technology (BMBF) and German Utilities (EVU). The
facility has a maximum power of 4 MW for steam production and a
maximum operating pressure of 10 MPa.

In the EU BWR R&D Cluster six test series with an emergency
condenser test bundle and four test series with a single tube
were performed in 1996. Within the Physics and Thermalhydraulics
Complementary Actions to the BWR Cluster (BWR/CA) the Forschungs
zentrum Rossendorf (FZR) e.V. has performed 10 post test calcula
tions and an additional blind test calculation of NOKO bundle
experiments. The tests were selected by FZJ. The results of
these calculations are presented in this paper.

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 the module
KONWAR has been developed and implemented in ATHLET. KONWAR is
based on the flow regime map of Tandon and includes several semi-
empirical correlations for the determination of the heat trans
fer coefficients. The post test calculations presented here
prove qualitatively and quantitatively the expected operation
mode and the capacity of the emergency condenser. Additionally
the blind calculation proves, that the improved version of
ATHLET (ATHLET with the extension KONWAR) is able to perform
proper calculations.

  • Lecture (Conference)
    TOPSAFE 98, Valencia 15.-17. April, Spanien, Beitrag TSC4-b
  • Contribution to external collection
    TOPSAFE 98, Valencia 15.-17. April, Spanien, Beitrag TSC4-b

Publ.-Id: 1078

Analytisches Modell zur Berechnung der Übertragungsfunkionen für das Neutronenflußrauschen in WWR-440 Reaktoren bei stochastischen Schwingungen der Regelelementunterteile

Meyer, K.; Hollstein, F.

Control elements of VVER-440 type reactors consist of absorber and fuel parts. They can approximately be considered as spatial double pendulums. The length of both parts is equal to the height of the core. In the present paper the main interest is directed to the neutron noise due to random vibrations of the fuel parts (lower parts of the pendulums). It is assumed, that the fuel parts of all control elements are completely inserted into the core. A homogeneous cylindrical reactor model is used to describe the neutron flux. It is also assumed, that the control elements can be excited to flow induced random 3D transverse oscillations and pendulum motions. The transfer functions for the considered two kinds of control element motions were calculated by means of the Prompt-Response-Approximation for the Modified-One-Group-Diffusion-Equation. Using numerical results, studies have been made to clear up the contribution of the random pendulum motions to the neutron noise.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-205
    ISSN: 1436-3976


Publ.-Id: 1077

Die Randschichtausbreitung bei der Plasma-Immersions-Ionenimplantation

Mändl, S.

  • Open Access Logo Wissenschaftlich-Technische Berichte / Forschungszentrum Rossendorf; FZR-206
    ISSN: 1436-3976


Publ.-Id: 1076

Microstructural Investigation of Ion Beam Synthesized Germanium Nanoclusters Embedded in SiO2 Layers

Markwitz, A.; Schmidt, B.; Matz, W.; Grötzschel, R.; Mücklich, A.

  • Nuclear Instruments and Methods in Physics Research B 142 (1998) 338-348

Publ.-Id: 1075

Determination of U(VI) Reduction after Bacterial Metabolization by Uranium LIII-Edge Xanes Spectroscopy

Reich, T.; Panak, P.; Mack, B.; Baraniak, L.; Denecke, M. A.; Hennig, C.; Roßberg, A.; Selenska-Pobell, S.; Bernhard, G.; Nitsche, H.

  • Other report
    HASYLAB Jahresbericht 1997

Publ.-Id: 1072

Uranium LIII XANES and EXAFS on the Uranyl Unit in a Single Crystal with Linear Polarized Synchrotron Radiation

Hennig, C.; Denecke, M. A.; Roßberg, A.; Zahn, G.; Reich, T.; Bernhard, G.; Nitsche, H.

  • Other report
    HASYLAB Jahresbericht 1997, 823 (1998)

Publ.-Id: 1071

N.C.A.11C-Labelling of Benzenoid Compounds in Ring Positions: Synthesis of 3-Nitro-/ 3-11C/ Toluene and 4-Nitro-/ 4-11C/ Toluene and Their Corresponding Toluidines

Mäding, P.; Steinbach, J.

  • Journal of Labelled Compounds and Radiopharmaceuticals XLI, 647-656 (1998)

Publ.-Id: 1070

Bestimmung der Neutronenflußdichten in den Bestrahlungseinrichtungen des BER II bei der HEU-LEU Umstellung

Stephan, I.; Gawlik, D.; Gatschke, W.

  • Lecture (Conference)
    Jahrestagung Kerntechnik 1998, Tagungsbericht, Mannheim 1998, S. 631 ff.
  • Contribution to proceedings
    Jahrestagung Kerntechnik 1998, Tagungsbericht, Mannheim 1998, S. 631 ff.

Publ.-Id: 1069

Finite Element Based Vibration Analysis of WWER-440 Reactors

Altstadt, E.; Weiß, F.-P.

A finite-element-model describing the mechanical vibrations of the whole
WWER-440 primary circuit was established to support the early detection of mechanical component faults. A special fluid-structure module was developed to consider the reaction forces of the fluid in the downcomer upon the moving core barrel and the rector pressure vessel. This fluid-structure interaction module is based on an approximated analytical 2D-solution of the coupled system of 3D fluid equations and the structural equations of motions. By means of the vibration model all eigenfrequencies up to 30 Hz and the corresponding mode shapes were calculated. It is shown that the fluid-structure interaction strongly influences those modes that lead to a relative displacement between reactor pressure vessel and core barrel. Moreover, by means of the model the shift of eigenfrequencies due to the degradation or to the failure of internal clamping and spring elements was investigated.Comparing the frequency spectra of the normal and the faulty structure, it could be proved that a
recognition of such degradations and failures even inside the reactor pressure vessel is possible by pure excore vibration measurements.

  • Lecture (Conference)
    ICONE‘98, International Conference on Nuclear Engineering, San Diego, May 10-15, 1998
  • Contribution to proceedings
    Proceedings of the 6th International Conference on Nuclear Engineering (ICONE-6) San Diego, May 10-15, 1998

Publ.-Id: 1066

Finite Element Based Stress Analysis of BWR Internals Exposed to Accident Loads

Altstadt, E.; Weiß, F.-P.; Werner, M.; Willschütz, H.-G.

During a hypothetical accident the reactor pressure vessel internals of boiling water reactors can be exposed to considerable loads resulting from temperature gradients and pressure waves. The finite element (FE) analysis is an efficient tool to evaluate the consequences of those loads by computing the maximum mechanical stresses in the components. 3 dimensional FE models were developed for the core shroud, the upper and the lower core supporting structure, the steam separator pipes and the feed water distributor. The models of core shroud, upper core support structure and lower core support structure were coupled by means of the substructure technique. All FE models can be used for thermal and for structural mechanical analyses. As an example the FE analysis for the case of a station black-out scenario (loss of power supply for the main circulating pumps) with subsequent emergency core cooling is demonstrated. The transient temperature distributions within the core shroud and within the steam dryer pipes as well were calculated based on the fluid temperatures and the heat transfer coefficients provided by thermo-hydraulic codes. At the maximum temperature gradients in the core shroud, the mechanical stress distribution was computed in a static analysis with the actual temperature field being the load. It could be shown that the maximum resulting material stresses do not exceed the permissible thresholds fixed in the appropriate regulations. Another scenario which was investigated is the break of a feed water line leading to a non-symmetric subpressure wave within the reactor pressure vessel. The dynamic structural response of the core shroud was assessed in a tranisient analysis. Even for this load case the maximum resulting stresses remain within the allowed limits at any time.

  • Lecture (Conference)
    Jahrestagung Kerntechnik‘98, München, 26.-28. Mai 1998, Tagungsbericht S. 721-724
  • Contribution to proceedings
    Jahrestagung Kerntechnik‘98, München, 26.-28. Mai 1998, Tagungsbericht S. 721-724

Publ.-Id: 1065

Dynamic in situ Diagnostics Using High-Energy Ion Beam Analysis

Möller, W.

  • Nuclear Instruments and Methods in Physics Research B136-138 (1998) 1203

Publ.-Id: 1064

Main Steam Line Break Analysis of a NPP with VVER by Means of the Coupled Code DYN3D/ATHLET

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.

Both versions of DYN3D for hexagonal and Cartesian fuel element geometry were 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 coupled code DYN3D/ATHLET was used to investigate the possibility of recriticality during an asymmetrical overcooling of the reactor core of a NPP with VVER-440 after a main steam line break (MSLB). This MSLB analysis was performed for hot zero power and end of fuel cycle conditions. Different coolant mixing conditions in the lower plenum of the reactor were simulated. The results show the importance of these conditions. In case of a realistic mixing model and without consideration of mixing, i.e. where each loop is connected to a particular 1/6 sector of the core, a recriticality after reactor scram was predicted. For ideal mixing only, recriticality can be avoided.

  • Contribution to proceedings
    Tagungsband Jahrestagung Kerntechnik '98, S. 15-19
  • Lecture (Conference)
    Jahrestagung Kerntechnik '98
  • Contribution to proceedings
    Proc. TOPSAFE `98, Session TSC-1a, ENS, Valencia (Spain), 1998
  • Lecture (Conference)
    TOPSAFE `98, Session TSC-1a, ENS, Valencia (Spain), 1998

Publ.-Id: 1063

Mechanical Response of a BWR to Loads Imposed by External Events

Altstadt, E.; Weiß, F.-P.; Werner, M.

In the case of external events (e.g. earthquake or explosion pressure wave) the reactor pressure vessel (RPV) and its internal components are excited to mechanical vibrations. In such cases it is important to know the dynamic component stress for the assessment of the mechanical integrity of the system.
For this reason a theoretical global vibration model based on the finite element method (FEM) was developed for a German BWR. The model comprises the RPV including the main coolant pumps (MCP), the control element drives, the core flux measuring pipes and the RPV internals.

  • Lecture (Conference)
    Proceedings of IMORN-27, Valencia, Nov. 18-20, 1997
  • Contribution to external collection
    Proceedings of IMORN-27, Valencia, Nov. 18-20, 1997

Publ.-Id: 1062

Calculation of the NOKO Test B6-4

Schaffrath, A.; Dumaz, P.

In 1997 a "BWR Physics and Thermohydraulic Complementary Action (BWR-CA)" was established to further assist and broaden the objectives of the "European BWR R&D Cluster for Innovative Passive Safety Systems". The activities are divided into 4 work packages (WP). The work presented in this paper is performed in WP2: Passive decay heat removal from the core region, where two different decay heat removal systems were investigated. These are isolation condensers (e.g. as operated in Gundremmingen A, Dodewaard or in the PANDA facility) or emergency condensers (e.g. as foreseen on the SWR1000 and tested in the NOKO facility).

Within the BWR Cluster the Forschungszentrum Jülich had performed 10 NO-KO tests. Six of these tests were carried out with a four tube bundle, four tests with a single tube. Several post test calculations of NOKO tests were performed in the BWR-CA by CEA with CATHARE V1.3U and FZR with an improved version of ATHLET Mod. 1.1 Cycle C. Additionally FZJ had specified data for a blind calculation. The blind NOKO calculation - as well as the other NOKO post test calculations - proves, that the modified version of CATHARE as well as the improved version of ATHLET (ATHLET coupled with KONWAR) are able to predict the global parameters in the range of the fluctuations of the measured values. In the next complementary action it is planned to perform additional post test calculations of the single tube experiments, experiments with gas/non-condensable mixtures and pretest calculations of a second optimized emergency condenser test bundle. The optimization suggest is to increase the heat transfer, which allows to decrease the number of heat exchanger tubes and the emergency condenser dimensions. This is desirable because it reduces the surface of the pressurized BWR circuit and the possibilities for leakages, which is a safety relevant task.

  • Contribution to proceedings
    Jahrestagung Kerntechnik '98 (1998), INFORUM GmbH, ISSN 0720-9207, S. 87-90
  • Lecture (Conference)
    Jahrestagung Kerntechnik '98 in München

Publ.-Id: 1061

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