[en] This report sums up the various conferences and symposia which were prompted by the tenth anniversary of the accident in the nuclear power plant of Chernobyl. It was shown that by the accident up to now 31 casualties among the emergency and rescue personal at the site. Offsite no increased number of casualties caused by the accident was observed up to now. In the countries with the highest impact Ukraine, Belarus and Russia, however, an increased number of infant thyroid cancer is observed which is substantially higher than after the nuclear detonations over Japanese cities. Contrary to often published media reports, however, up to now no increases in leukemia or other malignant deceases were observed, neither in the population of the concerned regions nor among the liquidators. The high ¹³⁷Cs activity concentration in the environment close to the power plant result in exclusion zone even today. The deposition values in Kiev, however, amount to only 30 kBq/m², in large areas of Ukraine they are below the average values in Austria of 22 kBq/m². For these areas as well as those outside the former Soviet Union the average doses were less than 1 mSv in the first year, a value which is less than one third of natural annual radiation exposure. Since the reactor accident the activity concentration has significally decreased resulting in an exposure as consequence of the reactor accident of less than 0,8 % of the exposure in the first year. In Austria the exposure in 1996 amounts to less than 0,3 % of natural radiation exposure. (author)

[en] At the fifth anniversary of the Chernobyl accident the initial situation at that time, the control of the consequences to Austria in the present light, as well as the knowledge gained from the accident and its consequences are described. A final estimate and appraisal of the total population dose by the accident alloted according to the individual exposure pathways and the dose reductions due to countermeasures by the authorities are given. The dose reduction in the following years is described. Five years later the external exposure was reduced to about 6 % of the values of the first year, the ingestion dose to about 5 % of the first-year-values. Finally, the current radiation situation is described and the dose contribution by foodstuff with elevated activity concentration is estimated. Also the consequences from the experience and knowledge obtained by the accident are described. (author)

[en] Data on cumulative Cs-137 and Sr-90 depositions both from nuclear weapons tests and the Chernobyl accident in Austria, Germany, UK and USA are given as well as the time dependence of Cs-137 concentrations from 1986 to 1992 in nutrients and drinking water in Austria and Germany. Finally the dose-to-population from the Chernobyl accident is compared to the natural radiation and even to that resulting from energy-saving sealing measures in living rooms. (Quittner)

[en] The nuclear power plants in operation or under construction in the CSFR which basically represent the pressure water type reactor of soviet design VVER-440 and VVER-1000, are briefly described. In particular, their safety aspects and possible safety defficiencies are discussed. The first generation VVER-440/230 possesses, apart from some positive safety features, severe safety defficiencies which may be only improved by substantial reconstructions, whereas with the second generation VVER-440/213 substantial improvements in these safety defficiences may be noticed. The third generation VVER-1000 largely corresponds to Western safety standards. With the second generation VVER-440/213 further safety research is required to better estimate the behaviour of the reactor under severe accident conditions, in particular, with regard to potential activity releases. (author)

[en] The radionuclides released from the destroyed reactor bloc 4 in Chernobyl and the worldwide distribution as well as the regionally varying deposition are described. The deposition in various countries is contrasted and compared to the average population dose in these countries as evaluated by the UNSCEAR-Report 1988. As expected, much higher dose values per unit deposition result for more southerly countries than for northerly ones. The fallout from the Chernobyl accident is compared to the fallout from nuclear weapons testing, both with regard to the global fallout and the fallout in some selected countries. The radiation exposure in the first year is contrasted to natural background level and the trend of the radiation exposure in the following years is described. (Author)

[en] The programme of P. Haas calculating protection values if building in the case of radioactive fallout has been tested in the Austrian Research Centre Seibersdorf. The stability of the programme has been investigated variating systematically input parameters. The usability in the context of different nuclear scenaria has been discussed. It turned out that the results are not correct if the calculated protection values are greater than 1000. The programme can also be used in the case of severe nuclear reactor accidents. (Suda)

[en] In order to perform the measurement of iodine isotopes with low gamma energies (¹²³J, ¹²⁵J, ¹²⁹J) in the exhaust surveillance of plants without sample preparation by direct gammaspectroscopic measurement, a series of deposition and retention experiments with commercially available active charcoal paper of 0.4 mm thickness were performed. In the case of no methyliodide being present in the exhaust air which may be considered typical for radiopharmaceutical production facilities, for hospitals (utilizers of radiopharmaceuticals) and low level radioactive waste incinerating plants, according to the ventilation rate in the bypass duct a deposition factor of from 95.6% (5.4 m³/h) to 99.8% (0.08 m³/h) is observed. With a one week application of the filter in the bypass duct 0.95 % of the originally deposited activity, with a two week application 1.4 % are resuspended. Thin active charcoal paper filters with comparatively low residence times of the bypass air in the filter, therefore, may be utilized in an optimum way for the determination of the activity concentrations in the exhaust ducts of these facilities

[en] The contribution tries to describe, according to the personal opinion of the author, the most important problems of communication between the population and the experts of the authorities, respectively. Based on the experiences after the Chernobyl accident and its consequences to the attitude and the reaction of the public, the basic errors and problems in the communication between radiation protection experts and the general public are reviewed and attempts to better manage them are outlined. (orig.)

[en] The radiation protection control report for the Research Centre Seibersdorf comprises the results of all measurements which have been performed during the year 1989 by the radiation protection control department to protect the employees and the environment of the Research Centre Seibersdorf. Personnel monitoring was carried out by TL-dosimetry to control the external dose, by body counting and excretion analysis for the surveillance of internal exposure according to the Austrian Radiation Protection Law. Monitoring of working places and laboratories was performed by external dose rate measurements, by smear tests and by measurements of the activity concentration in air. The radioactivity emissions from the ASTRA-reactor, the SAL, the waste-incineration plant and other institutes as well as the radioactive effluents from the water treatment plant were monitored. The environmental surveillance was supplemented by measurements of the activity content of surface air, tap- and surface water, soil and vegetation samples. The net dose amounted to less than 1% of the annual limit of 50 mSv for occupationally exposed workers. For a collective of 345 employees actually occupied in radiation areas the average annual dose including natural background radiation amounted 1,31 mSv/a (131 mrem/a) which is also less than 1% of the maximum value. 24 tabs., 14 figs. (Authors)

[en] Radionuclide contaminated soil adhered to plant surfaces can contribute to human ingestion dose. To determine this contribution, a method of ⁴⁶Sc neutron activation analysis was established and tested, by which a detection limit of 0.05 mg soil per g dry plant biomass can be obtained. In the field and greenhouse experiment the mass loading of soil on ryegrass (Lolium perenne L.) and broad bean (Vicia faba L.) was investigated and the contribution from rainsplash and wind erosion were evaluated separately. Soil retained on plant surfaces in field conditions in Seibersdorf/Austria was 5.77 ± 1.44 mg soil per g dry plant for ryegrass and 9.51 ± 0.73 mg soil per g dry plant for broad bean. Estimates of contribution from rainsplash and wind erosion to soil contamination of plant during the experimental period are 68 % and 32 % for broadbean, 47 % and 53 % for ryegrass, respectively. Mass loading results from field studies indicate that soil adhesion on plant surfaces can contribute up to 23 % of plant ¹³⁷Cs contamination, the transfer factors modified by mass loading decline differently, depending on ¹³⁷Cs concentration of the soil and the soil mass adhered to plant surfaces. (authors)