Search

In the context of severe accidents, large R&D efforts throughout the world are currently directed towards ex-vessel corium behaviour. Among the mitigation means which can be envisaged, the European industries and utilities are considering the implementation of a core-catcher outside the reactor pressure vessel in order to prevent basemat erosion and to stabilize and control the corium within the containment. The CSC project focused on two key phenomena for external core-catcher efficiency, reliability and safety: spreading and coolability. An experimental programme, covering different scenarios and including both simulant and real materials provided a lot of results which now constitute a large database and which enabled the qualification of computer codes.

For future reactors, the control and cooling of ex-vessel corium melts is under consideration to increase the passive safety features even for very unlikely severe accidents. In this context, different research activities are studying ex-vessel corium behaviour and control, including the implementation of a core cooling device outside the reactor pressure vessel in order to prevent basement erosion and to maintain the integrity of the containment. This paper describes current research on key phenomena which must be understood and quantified to be finally controlled by the cooling device. These are the release of corium melt from the pressure vessel, the temporary retention of the melt in the reactor cavity until melt through of the gate, spreading of the melt on a large surface, and finally the cooling and solidification of the melt by direct water contact. The experiments use high temperature melts which are similar to corium melts. Where necessary, models are developed to transfer the results to reactor scale.

new rem counter with a response tailored to match the shape of H*(10)/Φ as defined by ICRU and ICRP has been developed recently in the frame of a Technology Transfer Project of the Research Centre Karlsruhe with the industrial partner EG&G Berthold, Wildbad. In this paper, a carefully established, consistent fluence and ambient dose equivalent response function is provided for this detector as well as the effective response calculated for more than 500 neutron spectra from a catalogue.

The completely detached high confinement (CDH) regime established recently in high power ASDEX-Upgrade single null divertor discharges is described. The standard CDH mode scenario with feedback controlled external deuterium and neon puffing is analysed in detail with respect to its divertor detachment and confinement properties. Impurity transport and pumping effects and the density operation windows of the CDH mode are outlined. First results with other impurity radiators (N,Ar) are given. Finally the CDH mode operation space is discussed in terms of main chamber and scrape-off layer plus divertor radiation and possible consequences for future fusion experiments are outlined.

In response to their industrial needs six major German chemical companies have defined a common interface for the use of thermodynamics in different CAPE-applications. To prove the concept a prototype has been developed and applied to several industrial projects. This paper presents a plea for the introduction of an open CAPE environment. Such open standards have already been established in many other computer and information related areas.

Es werden Ergebnisse experimenteller Untersuchungen der Hydrodynamik einer pulsierten Siebbden-Extraktionskolonne im Technikumsmasstab mitgeteilt. Die Kolonne dient zur Trennung eines Gemisches aus Fettalkohol und Propandiol-1.2 mittels Wasser. Die Untersuchungen umfassen die Bestimmung der Flutgrenzen. Holdup-Werte sowie des Tropfenspektrums wobei im Vordergrund der Betrachtungen ein System mit sehr starkem Stofftransport steht. Die experimentellen Befunde sind bekannten Literaturkorrelationen gegenubergestellt. Fur die betrachtete Trennaufgabe konnten der Betriebsbereich der pulsierter Siebbodenextraktionskolonne sowie die erzielten Produktreinheiten ermittelt werden. Sie stellen eine Grundlage fur ein gesichertes Scale-up des Apparats. Experimental Studies of the Hydrodynamics of a Pulsed Sieve-Plate Extraction Column for Separation of Fatty Alcohol and Propandiol-1.2 Using Water Experimental results of the hydrodynamics of a pulsed sieve-plate extraction column in the pilot-scale will be presented. The column is used to separate the fatty alcohol/propandiol-1,2 using water. The studies concern the estimation of flooding conditions, hold-up and droplet size distribution. The emphasis is placed on a system with very high mass transfer. The experimental results were compared with published empirical correlations. It was possible to estimate the operating region of the pulsed sieve-plate extraction column and the obtainable product concentrations. The results form the basis for a safe scale up of the extractor.

ASDEX Upgrade is a poloidal divertor experiment very similar to ITER with respect to magnetic field properties and especially to the plasma boundary geometry. A large part of the programme on ASDEX Upgrade is therefore dedicated to investigating and optimizing reactor-relevant plasma boundary issues. This contribution is concerned with H-mode studies and edge physics in general. The L/H-power threshold, H-mode confinement, details of ELM dynamic and 'dithering' L/H-transitions will be discussed. The edge physics investigations are concerned with model calculations and validations, the characteristic 'approach' to the density limit (DL), target plate sputtering and the influence of hydrocarbons, asymmetries and drifts depending on the direction of the toroidal magnetic field, and finally first results of high-Z material experiments.

The delayed fission neutron spectra of 235 U, 333U and 239 Pu were measured for different time intervals after fission with proton recoil proportional counters. For these measurements, the spectra of the various time groups were determined. 14 MeV neutrons and, for 235 U, also thermal neutrons were used to induce fission. Where published experimental group spectra were available, comparisons with these results were made.

The variation of ionization, created in hydrogen filled proton-recoil proportional counters by protons with energies between 1 and 20 keV was measured, using quasi-monoenergetic neutrons from a slowing-down time spectrometer. The measured variation can be described by E = I−0.15+ exp (− I 1.76 ) , where E means the neutron energy (in keV) and I the ionization (in keV). The results are in satisfactory agreement with results of work described in literature and should contribute to improve the accuracy and reliability of proton-recoil neutron spectrometry in the low energy range.