Schnellbestimmung von Wasserstoff in Metallen

Theoretische Betrachtungen zur Diffusion des Wasserstoffs in Eisenlegierungen bei höheren Temperaturen bis in den Bereich des Schmelzpunktes. Beschreibung von apparativen Einrichtungen zur Ermittlung der Extraktionskinetik des Wasserstoffs beim Schmelzpunkt. Meßergebnisse. Apparative Anordnung zur Wasserstoffschnellbestimmung.     

Auflösungskinetik von technischen Graphiten in Eisenschmelzen

Aufkohlungsuntersuchungen mit verschiedenen körnigen Graphiten und mit Siliciumcarbid in Eisenschmelzen. Auswirkung der Badbewegung auf die Auflösungsgeschwindigkeit des Graphits im Induktions- und Tammannofen bei 1400 °C. Ermittlung der Aktivierungsenergie des Kohlenstoffübergangs in die Eisenschmelze. Aufstellung einer Hypothese über das Entstehen von neuen ?inneren Flächen? durch Spaltbarkeit der graphithaltigen Stoffe im Verlauf des Auflösungsvorganges.     

Meteorological parameters contributing to variability in 222Rn activity concentrations in soil gas at a site in Sapporo, Japan

Continuous ²²²Rn monitoring in soil gas since November 22, 2004 has revealed variability in activity concentration with time in the semi-natural woods on the campus of Hokkaido University in Sapporo, Japan. Among various factors affecting soil radon levels and variability, temperature was found to be dominant during three seasons when activity concentrations of ²²²Rn showed a diurnal high and nocturnal low with a boundary around 10 o'clock in the morning. This pattern was disturbed by low pressure fronts with occasional rain. The activity gradually decreased as soil temperatures decreased from late November to mid-December. After the ground surface was completely covered with snow, soil radon levels became low with a small fluctuation. There were several peaks of ²²²Rn on the time-series chart in winter. Those peaks appearing in early winter and early spring may be interpreted by considering meteorological parameters. In a few cases, the radon activity suddenly increased with increasing pressure in the soil at a depth of 10 cm, which may be associated with subsurface events such as seismic activity in the area.     

Prediction of light gas distribution in experimental containment facilities using the CFX4 code

Two- and three-dimensional simulations of experiments on atmosphere mixing and stratification in a nuclear power plant containment were performed with the computational fluid dynamics (CFD) code CFX4.4. Experimental data were obtained from the Institut de Radioprotection et de Sureté Nucléaire (France), where experiments on the TOSQAN facility were performed, and from Becker Technologies GmbH (Germany), where experiments on the ThAI facility were performed. The fluid inside the vessels was modeled as a single-phase gas atmosphere, and simple models for steam condensation on structures and in the atmosphere were introduced. The purpose was to assess the applicability of the CFD approach to simulate the behavior of light gases in containments at accident conditions. The comparisons of experimental and simulated results show that, despite a tendency to simulate more intensive mixing, the proposed approach may replicate the structure of the atmosphere reasonably well.     

Improved solidification influence modelling for Eulerian fuel-coolant interaction codes

Steam explosion experiments revealed important differences in the efficiency between simulant alumina and oxidic corium melts. The experimentally observed differences are importantly attributed to the differences in the melt droplets solidification and void production, which are limiting phenomena in the steam explosion process and have to be adequately modelled in fuel-coolant interaction codes. This article focuses on the modelling of the solidification effect. An improved solidification influence modelling approach for Eulerian fuel-coolant interaction codes was developed and is presented herein.The solidification influence modelling in fuel-coolant interaction codes is strongly related to the modelling of the temperature profile and the mechanical effect of the crust on the fragmentation process. Therefore the first objective was to introduce an improved temperature profile modelling and a fragmentation criterion for partly solidified droplets. The fragmentation criterion was based on the established modified Weber number, which considers the crust stiffness as a stabilizing force acting to retain the crust under presence of the hydrodynamic forces. The modified Weber number was validated on experimental data. The application of the developed improved solidification influence modelling enables an improved determination of the melt droplet mass, which can be efficiently involved in the fine fragmentation during the steam explosion process. Additionally, also the void production modelling is improved, because it is strongly related to the temperature profile modelling in the frame of the solidification influence modelling. Therefore the second objective was to enable an improved solidification influence modelling in codes with an Eulerian formulation of the droplet field. Two additional transported model parameters based on the most important droplets features regarding the fuel-coolant interaction behaviour, were derived. First, the crust stiffness was considered as an important property, because it enables the correct prediction of the amount of droplets participating in the fine fragmentation process during the explosion phase. Second, the heat flux from the droplet interior to the surface was considered as an important feature, because it enables to improve the surface temperature determination and reflects the history of the droplet's cooling. The last objective was to implement the improved solidification influence modelling into the Eulerian code MC3D. The first demonstrative simulations with the implemented modelling are promising and are showing improvements in the simulation capability.     

Application of code scaling, applicability and uncertainty methodology to large break LOCA analysis of two loop PWR

In NED 119, No. 1 (May 1990) a series of six papers published by a Technical Program Group presented a new methodology for the safety evaluation of emergency core cooling systems in nuclear power plants. This paper describes the application of that new methodology to the LB LOCA analysis of the two loop Westinghouse power plant. Results of the original work were used wherever possible, so that the analysis was finished in less than one man year of work. Steam generator plugging level and safety injection flow rate were used as additional uncertainty parameters, which had not been used in the original work. The computer code RELAP5/MOD2 was used. Response surface was generated by the regression analysis and by the artificial neural network like Optimal Statistical Estimator method. Results were compared also to the analytical calculation.     

Exposure to radon in dwellings in the Sharri community, Kosovo

Indoor air radon concentration was measured by exposing etchedtrack detectors in the sleeping and living rooms of 18 housesin 6 villages of the Sharri community in Kosovo. Values rangedfrom 24 to 209 Bq m^–3, with only one exceeding 200 Bqm^–3, with a geometric mean and geometric standard deviationof 95.4 Bq m^–3 and 1.6, respectively. On the basis ofthe assumption that the spring radon concentrations obtainedin this survey represent the yearly average, annual effectivedoses of residents were calculated; they range from 0.89 to4.7 mSv y^–1, with the geometric mean and geometric standarddeviation of 1.5 mSv y^–1 and 2.2, respectively. No mitigationmeasures are planned to be undertaken.     

A method for soil environmental quality evaluation for management and planning in urban areas

Soil represents a complex medium, which makes it difficult to evaluate its quality. In the past, soil quality evaluation was biased towards agricultural production rather than for purposes related to the broad range of functions and services that it performs. Soil function and soil quality in the urban environment differ due to the different needs and roles of soil within the diversity of urban land uses. The quality of urban soil should be evaluated to support public services for good environmental quality management. Planners should also adjust their decisions towards more sustainable urban design. Simple and applicable soil quality evaluation methods accompanied by an operations toolkit that could be used by laypeople are needed.This paper discusses soil functions, soil quality indicators, pedotransfer functions, and urban soil quality. It presents an urban soil quality evaluation method for different land uses within one particular evaluation system. The calculation of three one-value measures of soil quality are introduced: index of soil quality (expresses soil quality/suitability for a particular land use), soil environmental quality index (environmental value of soil) in terms of performing the crucial ecological functions of soil, and land use change index (land use planning impact assessment on soil resources). The use of the method is described in two procedures: urban soil quality control and soil evaluation for urban planning.