[en] Wetting behaviour plays an important role in the technology of liquid metals, but there is the problem that the conventional techniques for measuring wetting have an upper limiting temperature due to the evaporation of the metals and the aggressiveness of the vapours. After an introductory survey of the physical fundamentals of wetting and the conventional methods of measurement, the layout of a new measuring apparatus is described. The wetting angle theta of sodium in the temperature range from 520 to 720⁰C was measured on the metals Mo, Nb, Ta, W, Ni, TZM, high-grade steel, Inconel 600 and RTG 36 as well as on the ceramic materials Al₂O₃, ZrO₂ and Y₂O₃. (orig./TK)

[en] In March 2001, the Los Alamos National Laboratory (LANL) completed the replacement of 720 radioactively contaminated HEPA filters for $5.7M. This project was completed five months ahead of schedule and $6.0M under budget with no worker injuries or contaminations. Numerous health and safety, environmental, and waste disposal problems were overcome, including having to perform work in a radioactively contaminated work environment, that was also contaminated with perchlorates (potential explosive). High waste disposal costs were also an issue. A project risk analysis and government cost estimate determined that the cost of performing the work would be $11.8M. To reduce risk, a $1.2M comprehensive condition assessment was performed to determine the degree of toxic and radioactive contamination trapped on the HEPA filters; and to determine whether explosive concentrations of perchlorates were present. Workers from LANL and personnel from Waldheim International of Knoxville, TN collected hundreds of samples wearing personnel protective gear against radioactive, toxic, and explosive hazards. LANL also funded research at the New Mexico Institute of Mining and Technology to determine the explosivity of perchlorates. The data acquired from the condition assessment showed that toxic metals, toxic organic compounds, and explosive concentrations of perchlorates were absent. The data also showed that the extent of actinide metal contamination was less than expected, reducing the potential of transuranic waste generation by 50%. Consequently, $4.2M in cost savings and $1.8M in risk reduction were realized by increased worker productivity and waste segregation

[en] CRISPR/Cas9 has revolutionized site-directed mutagenesis in animal models. We have used this method in the rat for functional genomics and for the creation of novel disease models since this species is preferred for cardiovascular and behavioral studies. In a first novel disease model, we created a targeted mutation within a 15 bp region of the gene encoding phosphodiesterase 3A (PDE3A), which has been shown to be genetically linked to autosomal-dominant hypertension with brachydactyly (HTNB). This inherited disease clinically resembles salt-resistant essential hypertension and causes death by stroke before the age of 50 years. The CRISPR/Cas9-generated rat model carries a 9 bp deletion in the PDE3A gene analogous to a deletion also found in HTNB patients. Like in humans this deletion leads to a dominant disease characterized by hypertension and brachydactyly and thereby recapitulates HTNB. The mutated PDE3A gene drives mechanisms that increase peripheral vascular resistance causing hypertension. This new animal model will serve to elucidate the underlying mechanisms further and will facilitate the search for novel antihypertensive treatments.

[en] This paper discusses an experimental and analytical study on the shear behavior of thick-walled cylindrical support structures for pressure vessels. Since in the support structure the internal pressurization may be very low, the cylinder is assumed to be uncracked which distinguishes this study from many others which have been performed on precracked cylinders. The experimental phase of the study included the testing of three 1:30 scale models of thick-walled cylinders with different height to diameter ratios. Pertinent experimental results are presented in the paper and the contribution of shear deformations to the lateral deflection of the cylinder is evaluated. The shear failure surface was found to be a non-planar surface for which an analytical expression is developed. Based on this failure surface the she'r force transferred across the hoop reinforcement is evaluated and an analytical model for the ultimate shear capacity of uncracked thick-walled reinforced concrete cylinders is proposed. (orig.)

[en] The wetting angle of sodium on different pure metals (Ni,Ta,Nb,Mo,W), alloys (stainless steel 304L, Inconel 600, RTG 36, TZM) and oxides (Feldmuehle E37, Degussa AL23, sapphire, ZrO₂, ZrO₂, Y₂O₃) was measured in the temperature range from 520 to 720⁰C. A new measurement method was applied consisting of a combination of the classical sessile drop with a gas controlled heat pipe. The method is especially suited for high temperatures where the previous methods are impracticable because of excessive sodium evaporation. It has furthermore the advantage that the measurements are made under pure sodium vapour. In the temperature range mentioned all investigated materials are well wetted. The maximum measured wetting angle is 7.5⁰. The wetting angles are nearly independent from temperature, but they are show a time-dependency consisting in general of a rapid initial decrease and a reaching of the equilibrium value after about 1 hour. (Auth.)

[en] In conventional nuclear technology a lot of experience has been accumulated meanwhile for ferritic alloys, austenitic steels and Ni-based alloys as main component materials during R and D, design, construction and operation. Future Nuclear Power Plants such as Liquid Metal Reactors (LMRs), High Temperature Reactors (HTRs) or Fusion Reactors (FRs) are complex in the design and experiences with coolants/components are limited. Generally materials and their joining are key issues and their performance in components has not yet been demonstrated. Grades commonly used in fission reactors or conventional power systems have been proposed for the Gen IVs due to the extensive amount of work for the qualification and for code application. For high temperature operating conditions in heat exchangers of HTRs conventional alloys such as Alloy 800H or Alloy 617 have been specified in previous European projects (AVR, THTR, PNP,..). Both alloys have been tested already during the extensive German R and D activities for HTR/PNP projects between 1980-90. For the reactors of GEN IV, information gained from these activities and also from the European FBR -development (EFR) can be used and the available data may limit the extend of necessary R and D work. Design relevant properties especially of Alloy 617 from the previous R and D activities are summarized and compared with some recent results. The creep data from investigations for conventional power plants in the range of 700-800 deg. C fit well the data from the previous HTR programme. Problems such as reheat cracking are discussed. Critical issues of materials response to the helium environments are reviewed and the effect of ageing on mechanical properties. (author)

No abstract available

[en] The Pulse Step Modulator technology is widely used for several high voltage power supply applications, including the supply for gyrotrons, klystrons and neutral beam injectors. Thomson Broadcast and Multimedia is working on a new tube power supply system designed to operate several different klystron and gyrotron tubes for tube production testing. The system consists of the main power supply and the anode / body modulator. The main power supply is rated 160 kV / 20 A cw / 400 A pulse. The anode / body modulator is rated 100 kV / 250 mA. Both subsystems will be realised in PSM technology. The main power supply is a PSM system with some novel features. The target is to achieve very short rise times of 5 μs with low overshoot and also very low short circuit energies. The anode modulator requires 5 kHz modulation capability on high capacitive loads. This is achieved with a push-pull technology. The anode / body modulator is currently under testing in the Thomson factory. The mains power supply will be installed in the tube factory in autumn 2006. The paper gives an overview on the complete system. It will show the basic features and shows the status of the system testing. (author)

[en] Aim: Changes within the brain detected by MRI after chronic manganese poisoning raised the question whether morphological changes of the basal ganglia, particularly of the globus pallidus, could be detected after chronic occupational exposure to manganese dioxide. Results: No cases of parkinsonism were detected in clinical examinations or by other means. The mean manganese concentration in blood was 12 μg/l (range: 3.9-23.3 μg/l). In comparison to the upper reference value of 10 μg/l, 42 workers (56%) had a higher body burden. A significant positive correlation between manganese levels in blood and the PI (indicated by T₁-shortening) was observed as well as between the CBI and workplace-specific exposure. Brain atrophy was not detected in any of the observed cases. Conclusions: Long-term exposure to manganese dioxide dust correlates with the Pallidum-Index in MRI scans. Although the MRI findings have no current clinical relevance for individuals, further studies are necessary to evaluate specificity and potential prognostic value. (orig./AJ)

[en] We are studying the possibility to localize discharge phenomena in the Vivitron. This could give us informations about importance, repetition or cause of the discharges and so help us to plan and speed up maintenance. Simulations were made on a test bench and in the MP accelerator. Tests with specially designed piezoelectric sensors are scheduled in the CN accelerator with actual discharges, to establish the feasibility. Next year we will study data control problems and define an algorithm for the Vivitron