[en] In the German Federal States of Saxony, Saxony-Anhalt and Thuringia, centuries of mining and milling activities resulted in numerous residues with increased levels of natural radioactivity such as waste rock dumps and tailings ponds. These may have altered potential radiation exposures of the population significantly. Especially waste rock dumps from old mining activities as well as 20th century uranium mining may, due to their radon ("2"2"2Rn) exhalation capacity, lead to significant radiation exposures. They often lie close to or within residential areas. In order to study the impact on the natural radon level, the Federal Office for Radiation Protection (BfS) has run networks of radon measurement points in 16 former mining areas, together with 2 networks in regions not influenced by mining for comparison purposes. Representative overviews of the long-term outdoor radon concentrations could be established including estimates of regional background concentrations. Former mining and milling activities did not result in large-area impacts on the outdoor radon level. However, significantly increased radon concentrations were observed in close vicinity of shafts and large waste rock dumps. They are partly located in residential areas and need to be considered under radiation protection aspects. Examples are given that illustrate the consequences of the Wismut Ltd. Company's reclamation activities on the radon situation. - Highlights: • Long-term outdoor radon concentrations were measured in 16 former mining regions. • A method was developed to estimate outdoor radon background concentrations. • Detection thresholds and detection limits for mining influence were determined. • Implications of mining activities for natural outdoor radon level were studied. • Implications of reclamations for natural outdoor radon level were demonstrated

[en] To determine the natural radiation exposure due to outdoor radon ("2"2"2Rn) and its short-lived decay products in Germany, the Federal Office for Radiation Protection (BfS) conducted a measuring programme over three years. The annual mean radon concentration at 1.5 m above ground level was measured with solid-state track etch detectors at 173 measuring points in an even grid with a grid length of approx. 50 km. Furthermore, annual mean values of the equilibrium-equivalent radon concentration (EEC) and the equilibrium factor were estimated on the basis of the activity concentrations of "2"1"4Pb and "2"1"4Bi measured at 27 stations of the German Meteorological Service (DWD). Our study yielded a spatial mean outdoor radon concentration for Germany of 9 ± 1 Bq m"−"3 (median: 8 (−0.5/+1.0) Bq m"−"3), with regional means varying from 4.5 Bq m"−"3 in Hamburg to 14 Bq m"−"3 in Bavaria. The determined EEC are in a range from 1.4 to 11 Bq m"−"3. - Highlights: • Outdoor radon background concentrations ("2"2"2Rn) were measured in Germany. • Measurements were carried out at 173 locations over three years. • EEC and the equilibrium factor were estimated at 27 measuring points. • Effective dose due to outdoor radon was determined

No abstract available

[en] The speed of flow of the sodium is measured in two closely adjacent flow crossections using pairs of electrodes in the field of two disc-shaped permanent magnets made of AlNiCo 450, by means of measurements of running time of speed fluctuations. The result of the measurement is independent of the temperature of the sensor and the temperature of the sodium. The same arrangement makes it possible to determine the proportion by volume of the fission gas in sodium with a limiting freequency of several kHz. (DG)

[en] The magnetic probe immersed in the liquid metal flow (sodium) produces two voltages in two predetermined volumes on the Faraday induction principle, which are taken to two amplifiers. There is a correlator for determining the cross correlation function and the transport period. The outputs of the amplifiers are switched to a measuring instrument which responds quickly to determine the gas volume. The magnetic probe itself consists of a tube closed at one end, which is concentrically mounted in a jacket tube, and forms an annulus with this, through which the liquid metal flows. There are two disc-shaped permanent magnets made, for example, of AlNiCo 450 at a certain spacing from each other in the magnetic probe, and there are two pairs of electrodes associated with them. These give the voltage signals for the amplifiers. The material of the probes and the jacket tube is V2A. (HP)

[en] For the study of transverse electric dipole excitations in the nucleus ⁹⁰Zr with high-resolution inelastic electron scattering ten spectra in the excitation energy range Esub(x) = 9.4 MeV to 13.1 MeV at incident energies between E₀ = 30 MeV and 60 MeV were taken up under scattering anlges of theta = 93⁰, 129⁰, and 165⁰. The analysis of the cross sections was performed in DWBA under application of RPA amplitudes which were obtained in the framework of a separable residual interaction model. The existence of theoretically expected transverse E1 excitations could be detected with large probability, however an interpretation of the E1 transitions in terms of a fine structure of the giant electric dipole resonance cannot be excluded. For the studied excitation energy range a summarized transition strength of ΣB(E1,k)up = 0.81 (+0.74-0.38) e²fm² results. A remarkable E2 trength (2.4% EWSR) was observed in terms of a fine structure below Esub(x) < or approx. 11 MeV. For the magnetic quadrupole strength possible in the whole excitation energy range an upper limit of ΣB(M2,k)up <= 970 μsub(N)²fm² results. In the nucleus ²⁰⁸Pb the form factor of the Jsup(π) = 1⁺ state at Esub(x) = 5.846 MeV was studied. The strength of the transitions amounts to B(M1,k)up = 0.94 (+0.55-0.12) μsub(N)². (orig./HSI)

[en] In this paper details of the design and operation of an unique liquid metal flow meter probe are presented. Small permanent magnets are employed in the device. Flow rate measurements involve especially determination of the transit time for natural velocity fluctuations using a double-magnet configuration. Experiments have shown, that the used AlNiCo 450-permanentmagnets performed successfully for long times (10,000 h) at elevated temperatures (600⁰C). Flow meters have been employed in different test loops. They will be installed also in the BR2- and KNK II-reactors. The performance of a miniatur probe (2 mm diam.) and application of the device for the determination of the void fraction in a Na-inert gas stream are also presented. (orig.)

[en] An X-Ray-equipment is described which has been selected and assembled for the recording of fuel rod simulator-deformations during a loss of coolant accident using a movie technique. With this method it is possible to observe and record the ballooning of the simulator under conditions similar to those in a reactor. Some typical pictures are shown which show that the quality is high enough to allow a quantitative evaluation of the ballooning as a function of time. (orig.)

No abstract available

[en] A slice-selective saturation technique (FROGS), as well as a slice- and a volume-selective excitation technique (ISIS) were implemented on a whole-bod6y 1.5-T MR scanner. Electrocardiogram-triggered P-31 cardiac spectra of normal adult volunteers were acquired using the different localization techniques with a highly sensitive surface coil in the transmit/receive mode. Once a slice was chosen using slice-selective techniques, the geometric sensitivity of the surface coil was used to further restrict the region of interest. The results are discussed with regard to criteria for clinical applicability, efficacy of spatial localization; reproducibility; and tolerance for unavoidable errors in instrument settings