Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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 ...

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.

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.

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.

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.

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.

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.

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.

Das kritische J-Integral J_i 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 J_i 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.

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.

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.

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.

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.

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 (p_aO₂ = 32 ± 5 mm Hg) and hypercapnia ((p_aCO₂ = 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.

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.

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.

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.

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.

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.

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.

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 ...

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.

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.

Cobalt disilicide layers were produced by 70 keV Co2+ focused ion beam implantation into Si(111) at temperatures of about 400°C and subsequent annealing. The CoSi2 layer quality depends on pixel dwell-time and subtrate temperature. Only properly chosen parameters result in a continuous layer. The dwell-time (1-250 µs) and substrate temperature (355-400°C) dependence was investigated by scanning electron microscopy, reflectivity measurements and Rutherford backscattering spectroscopy/channeling. The results show that the irradiation damage increases with dwell-time and decreases with temperature, indicating an interplay between the damage creation rate and the dynamic annealing rate. Already after implantation of less than a tenth part of the dose required for continuous layer formation, the quality of the resulting CoSi2 layer is predertermined.

Die Entwicklung und der aktuelle Stand der Nutzung erneuerbarer Energien in Sachsen wird referiert. Als besonders ausbaufähig - da an der Schwelle zur Wirtschaftlichkeit stehend - erweist sich die Windenergienutzung. Begrenzt sind danach die Ressourcen an Wasserkraft und Biomasse, deren Beitrag an einer künftigen Stromversorgung jeweils unter 2% liegen kann.

Anhand ausgewählter Ergebnisse wird der aktuelle Stand der Nutzung der Photovoltaik vorgestellt. Trotz einer Reihe bemerkenswerter technischer Fortschritte bei den Hauptkomponenten und einer Vielzahl errichteter Demonstrationsanlagen liegen die Kosten von Solarstrom noch einen Faktor 10 zu hoch. Deshalb besteht nach wie vor ein erheblicher Forschungsbedarf, um diese Technologie zur Marktreife zu bringen.

The paper gives an overview on the use of renewable energies in Saxony. Small water power stations have been used here since the last century. After a downward movement in the last decades a revitalisation is visible in the last years. In 1997 water power stations with a total power of approximately 60 MW are in operation. The wind energy use has been developed dynamically since 1992. The installed power reaches 100 MW, supplying 1% of the electricity need in Saxony.

Voraussetzung zur Beurteilung der Leistungsfähigkeit von Photovoltaikanlagen ist die Kenntnis der Generatorleistung bei STC-Bedingungen PSTC . Da STC-Bedingungen im Betrieb der Anlage praktisch nicht auftreten, müssen die Generator-Kennlinien bei normalen Betriebsbedingungen gemessen werden und daraus mittels Näherungsverfahren die gesuchte Leistung ermittelt werden.
Im Beitrag werden die bei der Kennlinienmessung und den Umrechnungsverfahren auftretenden Fehler analysiert. Danach ist mit einem Gesamtfehler von 5,5 % zu rechnen.

As a complement of the EU-IPSS-BWR R&D Cluster project the "BWR-Physics and Thermohydraulics Complementary Actions" contributed to answer issues which are identified for the future BWR plants: The design of innovative components, an enlarged assesment of the performances and a better understanding of the underlying physical phenomena both thermohydraulics and neutronics and the interaction of the two.
Partners from 5 EU countries were involved in the project.
The report summarizes the main results (concerning thermal valves, isolation condensers, emergency condensor, building condenser and dynamical properties of BWR) of the project.

Im Bericht werden großflächige Untersuchungen zu windhöffigen Gebieten Sachsens vorgestellt. Für etwa 2/3 der Fläche Sachsens wurden die Windverhältnisse flächendeckend mit dem Programm WASP berechnet. Etwa 5% der Fläche Sachsens kann danach als windhöffig gelten. Als realistisches technisches Potential (Berücksichtigung von Bebauung, Naturschutzgebieten usw.) werden 5 TWh/a angesehen. Bis zum Jahr 2010 wird ein Erwartungspotential von 2 TWh/a geschätzt.

Ende 1996 waren in den neuen Bundesländern insgesamt Windenergieanlagen mit einer Leistung von 274 MW in Betrieb. Der Zuwachs zum Vorjahr betrug 120 MW. In Mecklenburg-Vorpommern erreichte die Windenergie einen Anteil von 2% am Nettostromverbrauch des Landes. In der Arbeit wird ferner auf die wirtschaftlichen Rahmenbedingungen der Windenergienutzung eingegangen.

An overview is given on the EU-IPSS-BWR R&D Cluster project "BWR-Physics and Thermohydraulics Complementary Actions". Six institutes/companies from 5 countries are working on three main topics:

• Design of innovative components (thermal valves, emergency condensers, isolation condensers and building condensers)
• Enlarged assesment of the performances of the innovative components
• Understanding of the physical phenomena which determine the dynamical behaviour of BWRs.

Within the framework of the German 1000-Roofs-PV-Programme, a total of 2011 grid connected PV systems with a total output of approximately 5.3 MWp were installed on the roofs of private houses. In addition to the recording and evaluation of the system data, another primary objective of the programme is the technical inspection of the PV systems and, in particular, the components used such as solar modules, cables, wires, diodes, fuses, terminals, overvoltage protection devices,DC isolating device and inverters. As some of the PV systems have now been in operation for as long as five years, it has been possible to gain valuable experience with regard to material time-to-failure, installation, environmental influences, maintenance, user behavior as well as on the stability and long term performance of the components used.

Die Erfahrungen der Vermessung und von durchgeführten Vorort-Inspektionen an mehr als 100 PV-Anlagen zeigen die derzeit noch bestehende Notwendigkeit der Durchführung solcher Inspektionen. Das Ziel besteht in der Gewährleistung der Funktion und der Qualität des Gesamtsystems. Auf einzelne häufiger anzutreffende Fehlerquellen wird detailliert eingegangen.

Im Bericht werden flächendeckende Berechnungen des Windpotentials in ausgewählten Gebieten Sachsens vorgestellt. Dazu wurden vorliegende Meßwerte aufbereitet und als Atlasdateien für das Windatlasprogramm WASP allgemein zugänglich gemacht. Dies schließt auch Untersuchungen zu den zugehörigen Repräsentanzgebieten ein. Es wird gezeigt, das mit modernen Windenergieanlagen in Sachsen Erträge bis 2000 Vollbenutzungsstunden und mehr erreicht werden können.

After the reunification of Germany, the energy situation in Germany has changed and particularly so in eastern Germany. There the demand for electric energy has suddenly decreased owing to industrial closures and accordingly, for this and for environmental reasons, the production of lignite has decreased as well. All nuclear capacity was shut down. Instead, a number of very modern high-performance coal-fired plants are being installed that also allow a sharp reduction of air pollution. Naturally, a modernisation and integration of the electrical grid is under way.

A promising approach for tracking tumours is to use radiolabelled derivatives of peptides such as Neurotensin (NT). This neuropeptide exhibits a high specific affinity to receptors located on various tumours like small cell lung carcinoma or human colon carcinoma. In order to develop a radiotracer to image the neurotensin receptor with PET the hexapeptide NT(8-13) and derivatives, such as pseudopeptides [Arg⁸psi(CH₂NH)Arg⁹]NT(8-13) and [NMe-Arg⁸]NT(8-13) may serve as valuable starting materials.
Our labelling experiments revealed that [¹⁸F]SFB reacts with N-terminal Arg-peptides like NT(8-13) or the metabolically stabilized pseudopeptide [Arg⁸psi(CH₂NH)Arg⁹]NT(8-13) with reasonable to good chemoselectivities in aqueous buffered solutions at pH values between 7.2 and 8.3. The radioactive product was identified by chromatographic comparison with a reference compound. The reactions carried out with nonradioactive SFB were shown to give the corresponding 4-FB peptides of which their structural identity was confirmed by proton NMR and MS studies. In summary the desired products of the reaction of [¹⁸F]SFB with NT(8-13) as well as [Arg⁸psi(CH₂NH)Arg⁹]NT(8-13) were obtained after HPLC purification with r.c.y. of up to 43 % (related to [¹⁸F]SFB; decay corrected) within 80 min.

Neurotensin (NT) ist ein regulatorisches Tridekapeptid (Pyr-Leu-Tyr-Glu-Asn-Lys-Pro-Arg-Arg-Pro-Tyr-Ile-Leu), das bei Säugetieren sowohl im Zentralen Nervensystem als auch im Intestinaltrakt gebildet wird. Membranrezeptoren für dieses Peptid finden sich in verschiedenen Geweben. Insbesondere in manchen Tumoren, u. a. dem kleinzelligen Lungenkarzinom und dem Karzinom der Bauchspeicheldrüse werden Neurotensinrezeptoren verstärkt exprimiert. Das Ziel unserer Untersuchungen bestand darin, das biologisch aktive Hexapeptid NT(8-13) mit dem Isotop ¹⁸F in möglichst hoher Chemo- und Regioselektivität für die Anwendung in der Positronen Emissions Tomographie zu markieren. Die Umsetzung von NT(8-13) mit [¹⁸F]SFB gelang in wässrigem Puffer bei pH 7.2 - 8.3. Das Reaktionsprodukt 4-[¹⁸F]FB-NT(8-13) wurde über eine semipräparative HPLC an RP-18 gereinigt und fällt mit einer radiochemischen Reinheit von >99.5% und einer radiochemischen Ausbeute von 43% (zerfallskorrigiert) an. Die Substanz entspricht in ihrer chromatographischen Charakteristik der Referenzsubstanz, die durch Umsetzung von NT(8-13) mit nichtradioaktivem SFB gewonnen wurde. Durch Einbeziehen von Pseudopeptiden wie [Arg⁸Psi(CH₂NH)Arg⁹]NT(8-13) möchten wir dem Problem der metabolischen Instabilität natürlicher Peptide in vivo begegnen.

The mean annual yield (700 kWh/a*kWp) and performance ratio (65%) of small grid connected PV systems which were installed within the 1000-Roofs-Programme in Germany are lower than expected. By investigating the parameters determining the performance ratio it could be shown that for well designed PV systems the PR should range within 70 to 80 %. The real power of the PV arrays as the most critical parameter of the performance ratio was measured with a newly developed PV system analyzer. In most investigated systems the measured power was 10 to 20 % lower than the nominal power. The revised performance data based on the measurements agree with the above given values. Based on a typical irradiation of 1100 kWh/m2 in module plane a mean annual yield of more than 800 kWh/a*kWp can be expected.

The increasing number of solar collector installations for larger appartment buildings proves that solar thermal energy is a favourable option for this type of water heaters. When operated in a preheat-mode such installations can reach a high collector loop efficiency which - besides the lower specific costs of material and installation - provides additional cost benefit. However, there may be a substantial decrease in collector loop efficiency which causes a reduction of solar yield when the actual hot water consumption stays far behind the design value. Therefore it is important to review the available data of hot water consumption in appartment buildings.
The present contribution presents and reviews recently measured hot water consumption data from various appartment buildings at different locations in Germany. The objects represent a broad choice of different design situations, varying e. g. in the number of appartments, the size of the appartments, the specific number of occupants per appartment and the social environment of the occupants. The locations comprise urban and rural dwellings. The data very recent (the earliest data taken in 1992) and therefore reflect today's lifestyle.

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 gravity-driven core flooding lines). In the framework of BWR Physics and Thermohydraulic Complementary Action (BWR-CA) to the EU BWR R&D Cluster emergency condenser tests were performed by Forschungszentrum Jülich at the NOKO test facility. In this paper post test calculations with ATHLET are presented, which aim at the determination of the removable power of the emergency condenser and its operation mode. The 1D thermal-hydraulic code ATHLET was extended by the module KONWAR for the calculation of the heat transfer coefficient during condensation in horizontal tubes. In addition, results of CFD-calculations using the code CFX-4 are presented, which investigate the natural convection during the heat up process at the secondary side of the NOKO test facility.

Diagnostically used ^99mTc kit radiopharmaceuticals were analyzed using capillary zone electrophoresis with radioactivity detection: ^99mTc-bis(bis(2-ethyloxyethyl)phosphino)ethane (^99mTc-Myoview, ^99mTc-Tetrofosmin), ^99mTc-trans(1,2-bis(dehydro-2,2,5,5,-tetramethyl-3-furanone-4-methylene-amino)ethane)-tris(3-methoxy-1-propyl)phosphine) (^99mTc-Technescan Q12, ^99mTc-Furifosmin), ^99mTc-methoxyisobutylisonitrile (^99mTc-MIBI), ^99mTc-_L,L-ethylenecysteine diethylester dimer (^99mTc-ECD), ^99mTc-d,l-hexamethylene propyleneamine oxime (^99mTc-HMPAO), ^99mTc-diethylenetriaminepentaacetic acid (^99mTc-DTPA), ^99mTc-ethylene hepatobiliary iminodiacetic acid (^99mTc-EHIDA), ^99mTc-_L,L-ethylenecysteine (^99mTc-EC), ^99mTc-mercaptoacetylglycylglycylglycine (^99mTc-MAG₃), ^99mTc-dimercaptosuccinic acid (^99mTc-DMSA), ^99mTc-methylene diphosphonate (^99mTc-MDP) and ^99mNaTcO₄. A pressure-driven capillary zone electrophoresis was employed to detect small anions of high electrophoretic mobility and cations within one run. Effective ^99mTc complex charges could be determined by a neutral internal standard. All complexes showed the expected electrophoretic behaviours in view of their charges. Pure products were obtained for the majority of the studied complexes. In the case of ^99mTc-Q12, ^99mTc-EHIDA and ^99mTc-MDP, complex mixtures were detected. The high potential of CE for the analysis of ^99mTc radiopharmaceuticals could be shown.

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 oxygen deprivation. However, the respective enzyme activities have not been measured in the living neonatal brain yet.
In this study, we have used ¹⁸F-labelled 6-fluoro-L-3,4-dihydroxyphenylalanine (FDOPA) together with Positron-Emission-Tomography (PET) to estimate the activity of the DOPA decarboxylase (DDC), the ultimate enzyme in the synthesis of dopamine (DA), in the brain of newborn piglets under normoxic and moderate asphyxial conditions.
The study was performed on 8 newborn piglets (2-5 days old). In each piglet two PET studies were performed under control conditions and during 2-hour asphyxia. Simultaneously, brain tissue pO₂ (LICOX pO₂ Monitor, GMS mbH, Kiel-Mielkendorf, Germany) was recorded, brain venous blood samples were obtained from sagittal sinus, and cerebral blood flow (CBF) was measured with col-ored microspheres. Cerebral metabolic rate of oxygen (CMRO2) was determined as the product of CBF and cerebral AVDO2. Asphyxia was induced by lowering the inspired fraction of oxygen from 0.35 to 0.12 and adding about 6 % CO₂ to the inspired gas, which resulted in moderate hypoxemia (39±6 mm Hg), hypercapnia (73±2 mm Hg) and a progredient combined respiratory/metabolic aci-dosis (p<0.01).
Asphyxia elicited an more than 3-fold increase of the CBF (p<0.01) so that CMRO2 remained un-changed throughout the asphyxial period. Despite this, brain tissue pO₂ was reduced from 19±4 mm Hg to 6±3 mm Hg (p<0.01). Blood-brain transfer of FDOPA as well as permeability-surface area product (PS) from striatum were unchanged. However, striatal synthesis rate of FDA (fluoro-dopamine) from FDOPA (k3) was significantly increased (p<0.01).
This increase of the DDC activity due to moderately reduced brain tissue pO₂ at unchanged CMRO2 may contribute to the ...

Since several years various groups of the Institute of Nuclear und Hadron Physics at Forschungszentrurn Rossendorf (FZR) are involved in medium energy physics projects where electromagnetic signals play a role:

(i) pp bremsstrahlung experiments at COSY-ToF have been proposed by a group from Dresden with FZR participation, and a large part of the ToF detector system has been
built in Rossendorf.
(ii) The FZR is presently building one of the large wire chamber planes for the HADES detector at GSI and is also actively taking part in the HADES commissioning.
(iii) The theory group here at Rossendorf is working in the field of dilepton production and other electromagnetic processes.
To discuss the research in these fields with colleagues from other places and to coordinate the efforts this mini-workshop was organized. The idea was to discuss the results of the experiments at different accelerators, the status of the calculations and the plans for future investigations. Besides bremsstrahlung special emphasis will be on dielectron production; other processes with electromagnetic signals (like vector-meson production) have also been discussed.

Heutige thermohydraulische Rechenprogramme, wie sie für die Auslegung und Si-cher-heitsanalyse chemisch/verfahrenstechnischer und nuklearer Anlagen eingesetzt wer-den, weisen entscheidende Defizite auf. Die Übertragbarkeit der Rechenergebnisse ist nur auf geometrische und thermohydraulische Verhältnisse gegeben, für die die einzelnen Komponenten des Modells adaptiert bzw. validiert wurden. Um in Zukunft eine Verbesserung der Übertragbarkeit, eine größere Nutzerunabhängigkeit der Simulationsergebnisse und eine Erhöhung der Modellgenauigkeit zu erreichen, wird weltweit auf den Übergang zu einer dreidimensionalen Modellierung mit Hilfe von CFD-Codes gesetzt. Dieses Ziel setzt neue Maßstäbe für die meßtechnische Instrumentierung der Experimente, die für die Entwicklung und Validierung der hierfür erforderlichen Modelle und Computercodes erforderlich sind. Bisher lag der Schwerpunkt auf der Messung von Massen-, Energie- und Impulsbilanzen über ganze Strömungskanäle und Geschwindigkeits- bzw. Dampfgehaltsverteilungen wurden vorrangig zur Ermittlung dieser Bilanzen und für ein qualitatives Verständnis der ablaufenden Prozesse erfaßt. Nun kommt es darauf an, die Verteilungen der Meßgrößen in einer räumlichen und zeitlichen Auflösung zu messen, die lokal quantitative Aussagen über Zwischenphasen-Austauschterme und einen Vergleich mit den dreidimensionalen Simulationsrechnungen erlauben. In den nachfolgenden Kapiteln werden die neuen Anforderungen an die Zweiphasenmeßtechnik am Beispiel der Messung von Phasenverteilungen definiert und einzelne, besonders vielversprechende Entwicklungs-richtungen diskutiert. Als eigenen Beitrag werden die Rossendorfer Arbeiten zum Gittersensor vorgestellt.

The nodal expansion method (NEM) used in the hexagonal version of the code DYN3D is based on the node averaged values of fluxes in the node volume and averaged values of fluxes and currents at the interfaces of the nodes [1]. The 3-dimensional neutron diffusion equation for two energy groups is split into a 2-dimensional equation in the hexagonal plane solved with the help of Bessel functions and a 1-dimensional equation in axial direction solved by polynomial expansion. The two equation systems are coupled by the transversal bucklings. The accuracy of this method is sufficient for the VVER-440 where the assembly pitch is 14.7 cm. The assemblies of the VVER-1000 have a larger pitch of 24.1 cm. Comparing with mathematical benchmarks for the VVER-1000 the maximal deviation of powers is in the order of 5%. The new nodal expansion method HEXNEM presented here uses a different flux expansion in the nodes. In addition to the average values at the interfaces of the hexagon the values at the corner points are included, too. It is shown that the accuracy is improved for the VVER-1000 problems.

The Cartesian version of the 3D core model DYN3D coupled with the thermohydraulic plant
model ATHLET will be used for the analysis of the OECD Main Steam Line Break (MSLB)
Benchmark which is based on real plant design and operational data of the TMI-1 PWR. The
three exercises of the benchmark are a point kinetics plant simulation (exercise 1), a
coupled 3D neutronics/core thermal-hydraulics evaluation of the core response (exercise 2)
and a best estimate coupled core-plant transient analysis (exercise 3). The presented
calculations of the exercise 2 are performed with the DYN3D code alone. The core boundary
conditions provided by calculations of the Penn State University with the TRAC-PF1/NEM code
system are used as input for the two scenarios of this exercise. Considering the best
estimate case (scenario 1) the reactor does not become critical during the transient.
Defining a more serious test for the codes, the efficiency of the control rods was
decreased to obtain a return to power in the transient (scenar io 2). The influence of
different thermohydraulic modelling on the results is investigated with the help of the
DYN3D calculations for scenario 2. The core averaged values as the total nuclear power or
the reactivity show a low sensitivity against the variation of the thermohydraulic model.
Considering local values as the maximum nodal Doppler temperature an impact of the
thermohydraulic model is observed.

The present paper reports the determination of dynamic crack initiation (Jid) values using the instrumented Charpy test. Under the condition of the impact bending test the critical step for evaluating of Jid is detection of ductile crack initiation point on the impact load displacement curve. In this paper the crack initiation is determined by using emission of acoustic waves (AE). Different kind of AE events can be observed during loading of a precracked and side-grooved Charpy size specimen. It was shown that characteristic AE signals appear in the vicinity of crack initiation for the first time. These results have been verified by the results of COD measurements using the inverted impact pendulum developed and installed by VTT Espoo/Finland (VTT Tester). Additionally "Cleavage R-Curves" (Ju- a), have been evaluated and the physical crack initiation toughness (JidSZW) was deduced by measurement of the stretch zone width (SZW).

There are numerous experiments for the exploration of the corium spreading behaviour, but comparable data have not been available up to now in the field of the long term behaviour of a corium expanded in a core catcher. The difficulty consists in the experimental simulation of the decay heat that can be neglected for the short-run course of events like relocation and spreading, which must, however, be considered during investigation of the long time behaviour.
Therefore the German GRS, defined together with Battelle Ingenieurtechnik a benchmark problem in order to determine particular problems and differences of CFD codes simulating an expanded corium and from this, requirements for a reasonable measurement of experiments, that will be performed later.
First the finite-volume-codes Comet 1.023, CFX 4.2 and CFX-TASCflow were used. To be able to make comparisons to a finite-element-code, now calculations are performed at the Institute of Safety Research at the Forschungszentrum Rossendorf with the code ANSYS/FLOTRAN.For the benchmark calculations of stage 1 a pure and liquid melt with internal heat sources was assumed uniformly distributed over the area of the planned core catcher of a EPR plant.
Using the Standard-k-e-turbulence model and assuming an initial state of a motionless superheated melt several large convection rolls will establish within the melt pool. The temperatures at the surface do not sink to a solidification level due to the enhanced convection heat transfer. The temperature gradients at the surface are relatively flat
while there are steep gradients at the ground where the no slip condition is applied. But even at the ground no solidification temperatures are observed.
Although the problem in the ANSYS-calculations is handled two-dimensional and not three-dimensional like in the finite-volume-codes, there are no fundamental deviations to the results of the other codes.

The coolant mixing in the downcomer and lower plenum depends significantly on the construction of the reactor vessel and on the instantaneous flow conditions. Therefore the Institute for Safety Research of Forschungszentrum Rossendorf has constructed a 1:5 mixing test facility representing the geometry of the German Konvoi type pressurized water reactor. The mock-up of the test facility and the measuring systems are explained in the poster.

In einer ersten und noch immer währenden Phase bewirkten die Informationstechnologien, dass die klassischen Geschäftsgänge von Bibliotheken rechnergestützt durchgeführt werden können. Das betrifft die Erwerbung, die Katalogisierung, die Nutzerverwaltung, den Aufbau von Online-Katalogen, die Zeitschriftenverwaltung, die Budgetverwaltung, die Fernleiheprozeduren u. a. Bibliotheksroutinen. Mit den sich schnell entwickelnden Technologien des INTERNET und des INTRANET werden für wissenschaftliche Bibliotheken neue Aufgabenfelder geschaffen. Diese entwickeln und erweitern sich sehr dynamisch. Für wissenschaftliche Bibliotheken, die in der Regel ein modernes wisschenschaftlich-technisches Umfeld haben, stellt diese Entwicklung eine grosse Herausforderung dar. Wenn sie diese Herausforderung annehmen, dann haben sie ein gute Chance auch weiterhin ein anerkannter Partner im Forschungsprozeß ihrer Trägereinrichtungen zu bleiben. Die Zentralbibliothek des Forschungszentrums Rossendorf bietet unter Nutzung dieser modernen Technologien und ausgehend von den Bedürfnissen der Wissenschaftler neue und nützliche Dienste an. Diese Dienste basieren auf informations- und literaturbezogenen Inhouse-Datenbanken. Diese Datenbanken werden dezentral gepflegt (die Wissenschaftler geben über WEB-Klients selbst in diese Datenbanken Datensaetze ein). Sie stehen ueber das INTRANET allen autorisierten Nutzern zu Verfügung. Inzwischen sind mehrere solcher Datenbanken zum Rossendorfer Virtuellen Katalog (ROKAT) verknüpft. Mit der Pflege der Inhouse-Datenbanken kommt die Bibliothek einer von ihr erwarteten Aufgabe, der Dokumentation der wissenschaftlichen Leistungsfähigkeit der Forschungseinrichtung in eleganter und personell verkraftbaren Weise nach. Im Vortrag wird auf die Persönliche Literaturdatenbank, eine Datenbank, die für Wissenschaftler geschaffen wurde und die gleichermaßen der Bibliotheksarbeit dient, näher eingegangen.

Titanium surfaces containing CaO and P2O5 were prepared by ion implantation of Ca and P and subsequent oxidation. Their reactivity to form hydroxyapatite was examined by in situ microscopically recording the surface mineralization in a simulated body fluid. The ion implanted surfaces exhibit enhanced mineralization by inducing heterogeneous nucleation, growth, and proliferation of hydroxyapatite, relative to a control sample of pure Ti. The surface induced reactivity was shown to relate to the mineral precursors Ca2+ and (HPO4)2- directly supplied from the surface and the substrate-mediated nucleation by hydroxylated surface TiO2.

In research towards the development of new atypical antipsychotic agents, one strategy is that the dopaminergic system can be modulated through manipulation of the serotonergic system. The synthesis and preliminary pharmacological evaluation of a series of potential atypical antipsychotic agents based on the structure of 1-(1,2-dihydro-2-acenaphthylenyl) piperazine 7 is described. 7e from this series showed significant affinities at the 5-HT_1A and 5-HT_2A receptor and moderate affinity at the D₂ receptor. 7e exhibits a high reversal of catalepsy induced by haloperidol indicating its atypical antipsychotic nature.

Preferred orientation in powder samples influences extendet X-ray absorption fine structure (EXAFS) measurements due to the polarization of synchrotron radiation. The polarization effect at the uranium LIII edge EXAFS and the analysis of preferred orientation is demonstrated using the natural mineral metatorbernite. For simple textures an X-ray diffraction measurement in Bragg-Brentano geometry allows to determine the crystallite orientation basing on a full pattern refinement including a preferred orientation model according to March-Dollase.

Euroconference and NEA Workshop Actinide-XAS-98

During recent years the interest in applying synchrotron radiation techniques to the investigation of radionuclides and actinides in particular has grown rapidly. Important research topics where a molecular-level understanding is mandatory include the behavior of radionuclides in the environment, nuclear waste management, radiopharmaceutical chemistry, and general actinide chemistry and physics.

On October 4-6, 1998 the first Euroconference and NEA Workshop on Speciation, Techniques, and Facilities for Radioactive Materials at Synchrotron Light Sources, Actinide-XAS-98, took place at the ESRF/ILL site. Over 90 scientists came from 13 European countries, USA, and Japan. Among them were 22 young scientists with an average age of 26 who benefited from travel awards provided by the European Commission. The main objectives of Actinide-XAS-98 were:

• to introduce the type of information that can be obtained from synchrotron-based techniques to environmental and radionuclide scientists,
• to report the latest results on radionuclide/actinide work, and
• to inform on protocols which are in place for actinide research at several synchrotron storage rings throughout the world.

The first day had tutorial character and introduced several synchrotron radiation techniques. H. Nitsche described the sources of environmental contamination by radionuclides, the importance of understanding the chemical behavior of radionuclides under environmental conditions, and the role x-ray absorption fine-structure (XAFS) spectroscopy plays in these investigations. D.C. Koningsberger, J. Goulon, and A. Filipponi presented the physical principle of XAFS and related experimental and theoretical aspects. V.I. Nefedov gave an introduction to x-ray photoelectron spectroscopy (XPS). D.K. Shuh described the complimentary application of XPS, near-edge x-ray absorption fine structure, and x-ray emission spectroscopy on actinide materials at e ...

Excited states in the N=Z nucleus 70Br have been investigated using the reaction 58Ni(16O,1p3n). Gamma rays were detected with one EUROBALL CLUSTER detector and three single HPGe detectors. Charged particles and neutrons were registered with the Rossendorf silicon ball and six modules of the EUROBALL neutron wall, respectively. The identification of gamma transitions in 70Br is based on the analysis of gamma-gamma-proton-neutron coincidences. A level scheme of 70Br has been established for the first time. It shows a multiplet-like structure of probably isospin T = 0 while T = 1 isobaric analogue states are not observed.

The paper describes the Rossendorf Beamline (ROBL) built by the Forschungszentrum Rossendorf at the ESRF. ROBL comprises two different and independently operating experimental stations: a radiochemistry laboratory for X-ray absorption spectroscopy of non-sealed radioactive samples and a general purpose materials research station for X-ray diffraction and reflectometry mainly of thin films and interfaces modified by ion beam techniques. The radiochemistry set-up is worldwide an unique installation at a modern synchrotron radiation source.

Small-angle correlations of pairs of nonidentical light charged particles
produced in central collisions of heavy ions
in the A=100 mass region at a beam energy of 400 AMeV are investigated with the FOPI detector system at GSI Darmstadt. The difference of longitudinal correlation functions with the
relative velocity parallel and anti-parallel to the center-of-mass velocity of the pair in the central source frame is studied. This method allows extracting the apparent
space-time differences of the emission of the charged particles. Comparing the correlations with results of a final-state interaction model delivers quantitative estimates of these asymmetries. Time delays as short as 1 fm/c or - alternatively - source radius differences of a few tenth fm are resolved.
The strong collective expansion of the participant zone introduces not only an apparent reduction of the source radius
but also a modification of the emission times. After correcting for both effects a complete sequence of space-time emission points of p, d, t, 3He, alpha particles is presented for the first time.

The flow of an electrically conducting fluid like sea-water can be
controlled by electromagnetic forces, i.e.~Lorentz-forces. These forces
may be generated by an appropriate chosen arrangement of permanent
magnets and electrodes. A strip like geometry as shown in fig. 1
produces a Lorentz-force with a streamwise component only. In a first
approximation this force is independent of the spanwise coordinate z and
decays exponentially with increasing wall distance y [1]. The successful
application of a surface parallel Lorentz force in streamwise direction
to control the flow around a cylinder has been demonstrated in
[2]. We consider here the action of such a force on a flat plate
boundary layer up to Re=9*10^5 and the flow around a NACA-0017-like
hydrofoil with Re<8*10^4. The experiments were carried out in a
saltwater facility and accompanied by flow visualizations in an open
channel with sodium hydroxide as the working fluid.

>From the boundary layer equations with the Lorentz-force term one gains
a characteristic parameter Z (Tsinober--Shtern parameter [1]) describing
the ratio of electromagnetic to viscous forces. If this parameter equals
one, the boundary layer equations have a solution with an exponential
flow profile similar to the asymptotic suction profile. A considerable
transition delay and therefore drastic drag reduction should be expected
from such a boundary layer [3], because the exponential profile has
proven to be much more stable than the Blasius one. Force balance
measurements on a flat plate show indeed the reduction of total drag by
more than 80\% (see fig. 2). However, this drag reduction is due to the
momentum added to the flow by the body force. The skin friction on the
contrary is even slightly increased, as can be concluded from the
velocity profiles in fig. 2. The reason for this behavior
lies in the real force distribution and probably the high turbulence level
of the environment. It is ...

The title compound is formed during the reaction of [ReN(Me2PhP)(Et2dtc)2] (Me2PhP = dimethylphenylphosphine, Et2dtc- = diethyldithiocarbamate) with excess BH3 in tetrahydrofurane. Two ReV atoms are linked by two (NBH2SBH3)4- units which act as three-dentate ligand via N, S and H forming an 8-membered metallacycle with additional co-ordination of a hydrido H atom trans to the nitrogen atom. The ReN multiple bond length is 1.70(1) Å which is only slightly longer than in the starting compound [ReN(Me2PhP)(Et2dtc)2] (1.666(6) Å).

In membrane electrolysis cells a layer of spherical foam was found grow-ing with increasing performance. At the top a transition to cell foam oc-curs. Near the cell bottom the boundary layer of gas fraction and velocity at the electrode was measured. The velocity boundary layer changes from laminar to turbulent.

Introduction:
The aim of this study was to identify the main sources of radiation doses to technologists during PET studies to minimize the radiation exposure in routine F-18-FDG scanning.

Materials and methods:
The radiation exposure, personal dose and hand dose to technologists were measured during preparation and performance of F-18-FDG-PET scans.
The PET studies included dynamic brain scans with manual blood sampling, as well as heart and whole body scans without blood sampling. The injected activities varied between 260 and 370 MBq.
Transport of radiopharmaceutical (max. 7 GBq) in a lead container, 3 cm wall thickness. Preparation of the syringes in a lead box with window of 3 cm lead-equivalent. During injection the syringes were handled with a special pair of tongs. The syringe was shielded with an 8 mm tungsten wall. To protect the technologist from radiation emitted by the patient during manual blood sampling a movable radiation shield (2 cm lead) was placed between patient and technologist.

Results and conclusions:

Personal dose [µSv] at: syringe preparation - <=1; injection - 3; blood sampling - 28; patient handling - 15. Hand dose (rings) [µSv]: 27 left, 13 right. Hand dose (tapes) [µSv]: 710 left and right.
Assuming 13 PET studies/week and 52 working weeks/year the personal dose may lead to about 10 mSv/a.
Our measurements indicate that the maximal allowed hand dose per year will be reached after preparations of 500 syringes. Therefore, in PET facilities with a high patient throughput an automatic filling device has to be used.

A new synthesis is described for three n.c.a. nitro-[1-¹¹C]benzenes 3a-c by condensation of nitro-[¹¹C]methane (1) with the appropriate pyrylium salts 2a-c in the presence of a base such as t-BuOK in t-BuOH. For synthesizing 4-nitro-[4-¹¹C]anisole (3a), tetrabutylammonium fluoride was successfully used as an auxiliary base. The best results were obtained in the synthesis of 3a. The conversion of 1 with 4-methoxypyrylium perchlorate (2a) yielded 3a of a radiochemical purity of up to 82 % and a mean specific radioactivity of 30 GBq/µmol (0.8 Ci/µmol) within 20 min. Related to 1, the reproducible radiochemical yields of 3a are in the range of 77 ± 5 % (decay-corrected). 2,6-Dimethyl-4-methoxy-nitro-[1-¹¹C]benzene (3b) was prepared by reaction of 1 with 2,6-dimethyl-4-methoxypyrylium perchlorate (2b) in radiochemical yields of about 37 % (decay-corrected) within 10 min. 2-Nitro-[2-¹¹C]mesitylene (3c) was obtained by condensation of 1 with 2,4,6-trimethylpyrylium tetrafluoroborate (2c) in radiochemical yields of about 29 % (decay-corrected) within 20 min. ¹³C/¹¹C Co-labelling experiments were carried out in order to confirm the identity of 3a-c and the position of the label.

High-purity niobium has successfully been used as neutron detector material in advanced neutron dosimetry. Reliable and accurate neutron dosimetry measurements are needed to control the neutron load of the reactor pressure vessel (RPV) during its operation. Neutrons-irradiation of the RPV material causes an embrittlement of the ferritic steel. The effect is highly safety-relevant and must, thus, be monitored. It is standard to use a set of several materials with different neutron activation or spallation reactions. An cases of the niobium detectors the nuclear reaction one makes use of 93Nb(n,n`)93mNb reaction. It is specially favourable because the energy dependence of this reaction is similar to the energy dependence of the damage function of the RPV material. Furthermore, the half-life is long (16.1 years) and results in a nearly constant weighting over the reactor cycle. Therefore, the decay correction is only small in comparison with other detectors.
Niobium of low purity is not appropriate for this purpose. Impurities can affect additional activation reactions. Especially detrimental is tantalum. The neutron capture of 181Ta leads to 182Ta resulting in high energy gamma lines (1121,1122 keV) and added excitation of the detected 16 and 18 keV niobium lines. The correction of these effects is difficult and yields additional errors.
The requirements of the purity are strict: a good niobium detector must not have a Ta concentration of more than 1 ppm.
The niobium was produced by a technology which consists of an electrolytic refining, melting processes and mechanical treatment. In the cathodic niobium (electrolysis conditions: T = 750°C, j=0.4 mA/mm²) the so-called "problematic element" Ta could not be detected by instrumental neutron-activation analysis (cTa <<1 at.ppm).
With the niobium produced in this way, the neutron fluence at the VVER-type RPVs of the nuclear power plants in Greifswald (Germany), Rovno, and Balakovo (Russia) were determined. Int ...

Euroconference and NEA Workshop Actinide-XAS-98

Structures of Iodophenyltellurium(II) and Diiododi-(b-naphtyl-tellurium(IV)

Abstract. The reactions between diphenyl ditelluride, (PhTe)2, or di(b-naphtyl)-ditelluride, (b-naphtylTe)2, with equivalent amounts of iodine have been reinvestigated and the crystal and molecular structures of iodophenyltellurium(II), (PhTeI)4, and diiododi-(b-naphtyl)-tellurium(IV), (b-naphtyl)2TeI2, have been determined.
The structure of iodophenyltellurium(II) (space group Cc, a = 13.850(5) Å, b = 13.852(3) Å, c = 16.494(6) Å and b = 101.69(2)°, Z = 4) is built up by four PhTeI units which are linked by weak Te-Te interactions with Te-Te distances between 3.152(5) Å and 3.182(4) Å. The angles between the tellurium atoms are approximately 90° giving an almost perfect square. Long range secondary bonds (Te ---- I: about 4.2 Å) link the tetrameric units to give an infinite two-dimensional network.
Iodo(b-naphtyl)tellurium(II) is less stable than the phenyl derivative. Solutions of this compound decompose under formation of elemental tellurium and (b-naphtyl)2TeI2. (b-Naphtyl)2TeI2 crystallises in the monoclinic space group C 2/c (a = 21.198(6) Å, b = 5.8921(8) Å, c = 16.651(5) Å, b = 114.77(2)°). The tellurium atom is situated on a two-fold crystallographic axis and Te-I and Te-C bond lengths of 2.899(1) and 2.108(7) Å have been determined.

Noncovalent binding of pertechnetate may be of considerable interest as a new approach to labelling organic compounds with technetium without any reduction step, and for removal of pertechnetate as an environmental contaminant. Effective and selective complexation of pertechnetate should be realisable on the basis of molecular assembled supramolecular receptors that can provide multi-point fixation of tetrahedral anion pertechnetate as shown in the figure.

This paper reports on complexation experiments of pertechnetate and its nonradioactive congener perrhenate using different guanidinium compounds. The characterisation of these Tc(VII) and Re(VII) complexes are supported by X-ray crystal structures, TLC, infrared and NMR spectra. Liquid-liquid extraction studies are performed in order to monitor the influence of competition anions on phase transfer and to evaluate the stoichiometry of the complexes extracted. Lipophilicity and ionisation properties of guanidinium hosts and their Tc(VII)/Re(VII) complexes are determined by RP-HPLC. Molecular modeling calculations are used for the interpretation of the experimental results.

A new computer program has been developed for the control of the GSI Rotating Wheel Multi Detector Apparatus (ROMA) running under the Windows 95 and Windows NT 4.0 operating systems. It can be fitted to a lot of detection tasks in a highly flexible way.

The ROMA apparatus [1] has been used successfully for a lot of chemical investiga-tions of transactinide elements. In preparation of our seaborgium experiment at GSI in sum-mer 1998 [2] we developed a new control program. This was necessary because the old control code was running on an ATARI computer. In case of a damage of this computer, there would not have been the possibility of a replacement, which could possibly cancel the experiment.
The new program was designed to fulfill our special experimental requirements. A second feature is its support of the usual working conditions in a long running beam time. That means, persons without a deep understanding of a computer should be able to use this program without any difficulties, even if the programmer is not available. Thirdly, it should be highly flexible in order to adapt it to new experimental demands. Finally, the program should be to a great extent independent of the experiment hardware in order to be usable for similar apparatuses.
The program is written entire-ly in the C++ language using the Borland C++ Builder 1.0 programming environment based on the object oriented Virtual Component Library.

The program has to carry out the following tasks:

· control of the ROMA wheel movements according to the actual experiment;
· enabling and disabling the nuclear spectros-copy data acquisition;
· sending information about the actual ROMA status to the data acquisition hardware;
· processing requests of the acquisition hardware (e. g. switching in "daughter mode" [3]);
· processing user input (e. g. experiment and wheel setup dialog boxes).

The program is a Microsoft Windows applicatio ...

The paper presents high speed measurements of the transient void fraction distribution in the cavitating flow behind fast acting butterfly valves. A new electrode mesh sensor with a time resolution of 1024 frames per second was used. As a result, a new method to avoid cavitational water hammers was found.

A new wire-mesh sensor for gas-liquid flows is presented. Air-water mixtures in a vertical pipe were studied in a wide range of superficial ve-locities. Gas fraction and gas velocity profiles as well as a high resolution imaging of the flow structure are obtained. A volume flow rate measure-ment is feasible.

Needle Shaped Conductivity Probes have been applied to measure the properties of aqueous alcohol foams. Simultaneous usage of gamma densitometry and video imaging should allow a calibration and prove the values of the probe. The results show that the conductivity probes are able to measure in the foam zone as well as in the bubbly flow whereas the geometry of the foam causes some problems to detect reliably the foam bubbles.

The synthesis of n.c.a. [1-¹¹C]phenol (3) which is a further important aromatic ¹¹C unit for potential PET radiotracers is decribed for the first time. [1-¹¹C]aniline (1) was diazotized and the [1-¹¹C]benzenediazonium bromide (2) formed was concentrated in situ to give 3. Before diazotization, 1 had to be purified twice by means of an adsorber resin and a cation exchange resin. Starting from the purified 1, 3 was obtained in a radiochemical purity of about 79 % within 10 min. Related to crude 1 from the one-pot process, thereproducible radiochemical yield of 3 was about 16 % (decay-corrected). ¹³C/¹¹C Co-labelling experiments were carried out in order to confirm the identity of 3 and the position of the label.

The flow of electrically conducting fluids like sea water around bodies can be controlled by electromagnetic forces. These forces may be generated by a suitably chosen arrangement of permanent magnets and electrodes on the surface of the body.

We consider surface parallel Lorentz-forces acting in streamwise direction.This configuration allows to prevent the boundary layer from separation, resulting in higher lift and/or lower form drag of the body.Experimental results on the flow around a circular cylinder, an inclined plate and a hydrofoil are presented for Reynolds numbers up to 10**5. In the caseof the cylinder both steady and time-periodic forcing are applied.

The experiments were carried out in an open channel with sodium hydroxide as the working fluid and in a sea water facility. Flow visualizations showing serious separation delays will be presented together with values for drag and lift in different configurations.

Direct numerical simulations at low Reynolds numbers confirm the physical tendencies of the experiments.

Recently 3D neutron kinetics core models have been coupled to advanced thermohydraulics system codes. These coupled codes can be used for the analysis of the whole reactor system. In the framework of the international "Atomic Energy Research" (AER) association on VVER Reactor Physics and Reactor Safety, a benchmark for these code systems was defined. The reference reactor is the Russian VVER-440. The response of the reactor core to a main steam header break should be investigated. Solutions were received from the following five organizations: Kurchatov Institute Moscow (Russia), VTT Energy Espoo (Finland), Nuclear Research Institute Rez (Czech Republic), KFKI AEKI Budapest (Hungary) and Forschungszentrum Rossendorf (Germany). The paper presents an overview of the results of the benchmark. A good agreement in the thermohydraulic behaviour can be observed, the main differences between the solutions arise from the use of different nuclear data.

Extraction of pertechnetate with bicyclic guanidinium compounds has been studied in the system KTcO₄-buffer-H₂O/ligand-trichloromethane. Extraction data of guanidinium ligands have been compared with trialkylmethylammonium (Aliquat 336), tetraphenylphosphonium and tetraphenylarsonium chloride. The lipophilicity of extractants investigated was determined by RP-HPLC. The efficiency of pertechnetate extraction correlates with the lipophilicity of the guanidinium compounds. 1:1 complex formation in the organic phase was observed. The influence of hydroxide, chloride and bicarbonate on the pertechnetate extraction has been investigated. Pertechnetate is extracted with great preference over OH^-, Cl^- and HCO₃ ^-.

The tetraphenylphosphonium salt of tetra(1-methyl-1,2,3,4-tetrazole-5-thiolato)aurate(III) crystallizes as H2O solvate in the monoclinic space group C2/c with the gold atom situated on an inversion centre. The tetrazole rings are arranged almost orthogonally to the square coordination sphere. Au-S-C angles of 106.16(11) and 107.14(12)° have been found.

Für die Untersuchung von transienten Zweiphasenströmungen in Rohrleitungen, bzw. Rohrleitungssegmenten wurden im Fraunhofer-Institut für Umwelt, Sicherheits- und Energietechnik e.V. Oberhausen (UMSICHT) eine Druckstoßanlage als Freiluftanlage errichtet. Diese Anlage besteht aus zwei ca. 200 m langen Rohrleitungen mit den Nennweiten DN50 und DN100. Aufgabe des FZR war die Instrumentierung der Anlage mit Zweiphasenmeßtechnik sowie die Mitwirkung bei den experimentellen Untersuchungen und deren Interpretation. Die Anlage wurde vom FZR mit 16 nadelförmigen Leitfähigkeitssonden, einem neuartigen Gittersensor-Meßsystem und Ultraschall-Aufnehmern ausgerüstet. Mit den Gittersensoren, die 1024 Messungen pro Sekunde ermöglichten, wurde die bisher zugängliche Zeitauflösung hinsichtlich der Erfassung des gesamten Strömungsquerschnitts um etwa eine Größenordnung überboten. Die hinter einer schnellschließenden Klappe auftretenden großräumige Kavitationsblasen wurden visualisiert, deren maximale Ausdehnung in Strömungsrichtung mit zunehmender Strömungsgeschwindigkeit und Rohrleitungslänge anwächst. Innerhalb der Kavitationsblase liegt kurze Zeit nach dem Schließen der Armatur eine geschichtete Strömung vor. Die durch den Gegendruck abgebremste und erneut in Richtung auf die Armatur beschleunigte Flüssigkeitssäule prallt als Schwall auf die geschlossene Armatur, wodurch der Kavitationsschlag entsteht. Nachfolgend werden durch Reflexionen der Druckwelle weitere Kavitationsblasen erzeugt. In der Klappe tritt während des Schließvorgangs Kavitation auf. Die charakteristischen Dampfgehaltsverteilungen sind stark transient und weisen ausgeprägte räumliche Verteilungen auf. Auch vor der schnellschließenden Armatur treten unter bestimmten Bedingungen Kavitationsblasen auf, wenn die anfängliche Druckwelle vom Anfang der Rohrleitung als Entspannungswelle reflektiert wird und zurückkehrt.

The physico-chemical characterization of seaborgium as oxide hydroxide, performed in 1998 at the GSI accelerator UNILAC, continues earlier gas chromatographic studies of seabor-gium oxychlorides [1, 2]. In our former studies seaborgium behaved like a typical group 6 element despite the relativistic effects, which are increasing with the nuclear charge and cause unexpected chemical properties of the lighter transactinide elements rutherfordium and dubnium [3, 4]. To characterize seaborgium its properties have to be compared with those of other elements, first of all its homologues molybdenum and tungsten. The clear gra-dation of their chemical properties favors the oxides of the group 6 elements for studies of the influence of relativistic effects on the chemical properties of seaborgium. All the more as gas chromatographic studies of oxides or oxide hydroxides, respectively, provide high selec-tivity with regard to the lighter transactinides and interfering actinides. But on the other hand, the surface reactions dissociative adsorption and associative desorption governing the reac-tion ...

Mit dem bildgebenden Verfahren der Positronen-Emissions Tomographie (PET) können Transportprozesse, Enzymreaktionen und Rezeptoren in vivo, räumlich, zeitlich und quantitativ mit großer Sensitivität erfaßt werden. Entsprechend werden auch diagnostische Fragestellungen in der Medizin gelöst, die Veränderungen der genannten biochemischen Prozesse beinhalten. Eine Voraussetzung sind mit Positronenstrahlern z. B. mit ¹⁸F (T_1/2=110 min) oder ¹¹C (T_1/2=20 min) markierte Radiotracer, die hochspezifisch mit biologischen Bin-dungspartnern reagieren und eine geeignete Biokinetik besitzen. Zu solchen Radiotracern gehören auch ra-dioaktiv markierte Peptide und deren Derivate. In klinischen Untersuchungen werden bereits radioaktiv mar-kierte Somatostatinanaloga zur Tumordetektion eingesetzt (1). Ein ähnliches Potential besitzt auch Neuro-tensin (NT). Die G-Protein abhängigen Membranrezeptoren für NT werden auch in verschiedenen Tumoren, z. B. kleinzelligen Lungenkarzinomen, Pankreaskarzinomen u. a., überexprimiert (2). Ziel der Arbeiten ist es, einen Radiotracer zu entwickeln, der die in vivo Darstellung solcher Tumore mit PET ermöglicht. Dazu sind NT-Agonisten erforderlich, die durch Bindung und durch Internalisierung in der Targetregion angereichert werden, gleichzeitig aber auch schnell aus dem Blut eliminiert werden.
Die erstmalig mit 4-[¹⁸F]Fluorsuccinimidylbenzoat an der alpha-Aminogruppe des N-Terminus ¹⁸F-markierten lysinfreien Peptide 4-[¹⁸F]FB-NT(8-13) und 4-[¹⁸F]FB-[Arg⁸Y(CH₂NH)Arg⁹]NT(8-13) (4) wurden in vitro auf Rezeptoraffinität, Bindung an NT-Rezeptoren in Hirnschnitten und in vivo mit PET und durch Messung der Verteilung in Ratten charakterisiert.
Zur Affinitätsbestimmung in vitro wurden die radioaktiv markierten Peptide eine Stunde bei 37°C mit den stabil NTR1-Rezeptor exprimierenden HT-29 Zellen inkubiert. Beide Peptide binden an diesen Rezeptor. Für 4-[¹⁸F]FB-NT(8-13) wurde ein K_D von 5,1 nM ermittelt. In Simultanuntersuchungen mit [³H]NT korreliert deren Rez ...

The Rossendorf PET Center has a special feature: its PET cyclotron and the radiochemical laboratories are 500 metres away from each other. The distance is bridged by our radionuclide transport system (RATS).
Details of RATS such as layout, technical parameters, control system, radiation protection and our experience in long-distance transport of radionuclides, are indicated below.

Abstract. The title compound is formed from the five-coordinate [ReN(Et2dtc)2] upon reaction with B(C6F5)3. As a consequence of the formation of a nitrido bridge between Re and B the structural trans influence of the nitrido ligand decreases and its trans position which is not occupied in the edduct becomes available for co-ordination. The dimer is built up by two [Re{NB(C6F5)3}(Et2dtc)2] units which are linked by weak bonds between the metal and each one sulphur atom of the neighbouring unit (Re-S: 2.856(6) and 2.835(6) Å, respectively).
Keywords: Rhenium complexes, Nitrido bridges, Crystal structure, Dimerization

Abstract
A review on the synthesis and properties of the organometallic aqua-ion [M(OH2)3(CO)3]+ (M = Re, 99Tc, 99mTc), as relevant for radiopharmaceutical application, is presented. These important starting compounds can be prepared quantitatively a) on the no carrier added level (99mTc) in water or b) in organic solvents (Re, 99Tc) at atmospheric pressure in a short time and from [MO4]-. The main characteristics of these carbonyl complexes are the high substitution stability of the three CO ligands and the substitution lability of the coordinated water molecules. [M(OH2)3(CO)3]+ can be considered as a "semi aquo-ion". On the macroscopic level, upon titration with OH-, hydroxo-bridged oligomers have been isolated and characterized. The formation of hydroxo-bridged complexes is a consequence of the considerable Broenstedt acidity of [M(OH2)3(CO)3]+, whereas on the no carrier added level (n.c.a.) no such behavior was observed. Conditions and products of the water exchange by imidazole (im) and derivatives thereof (histamine, histidine) will be presented. The different mononuclear complexes with these ligands are of extraordinary inertness, which is the base for a potential application in biology and nuclear medicine. Finally, as a base for bioorganometallic chemistry, the adoption of the results from basic coordination chemistry to the labeling of biomolecules with an organometallic moiety will be exemplified with a selected penta-peptide and a recombinant single chain fragment.
Keywords: Tc-carbonyls, Tc-peptide complexes, scFv, cancer diagnosis, radiopharmacy

Synthesis, Characterization and Structure of Carbonyl and Hydrido Isocyanato Complexes of Ruthenium

Abstract. [Ru(CO)H(NCO)(PPh2Me)3] is formed during the reaction between [RuCl3(PPh2Me)3] and NaOCN in EtOH. The compound crystallizes in the monoclinic space group P21/n (a=1256.4(4), b=1487.2(2), c=1993.5(5) pm, b=97.28(1)°, Z=4). The distorted octahedral coordination sphere of RuII contains the phosphine ligands in meridional arrangement, their P atoms forming a plane together with the hydride ligand.
The reaction of [RuCl3(PPh3)2] with NaOCN in EtOH yields [Ru(NCO)-(CO)(CH3COO)-(PPh3)2] with trans coordinated Ph3P ligands.
The formation of hydrido, carbonyl and acetato ligands are due to the reaction of the transition metal with the solvent ethanol.

CoSi2 layers were produced by 70 keV Co focused ion implantation into (111)Si. Within a comparative study the CoSi2 layer quality and implantation damage were investigated as a function of pixel dwell-time and substrate temperature. Irradiation damage measurements were done by micro-Raman analysis. The results suggest that the dwell-time dependence of the CoSi2 layer formation - continuous layers for short and disrupted for long dwell-time - is caused by an adequate change from crystalline to amorphous silicon.

Using the spectral function F'(z)/F(z) the RPA correlation energy and other properties of a finite system can be written as a contour integral in a compact way. This yields a transparent expression and reduces drastically the numerical efforts for obtaining reliable values. The method applied to pairing vibrations in rotating nuclei as an illustrative example.