[en] The report provides an improved data base with respect to indoor inhalation eposure after severe accidents in nuclear facilities. The improvement was achieved by an extensive exploration of the related literature, both in the nuclear and in the field of chemical toxicants. The results in terms of dose reduction factors due to inhalation of indoor instead of outdoor air is presented for two cases: without any emergency-related counter measures and for a case with protection measures, such as closing of all doors and windows and switching air conditioning equipments to recirculation during cloud passage, and intensive airing afterwards. Depending on the physico-chemical form of the radionuclides and specific room categories, reduction factors show a range between 0.004 and 1. (orig./HP)

[en] For the purposes of this study, the ecological area affected in connection with the radiation exposure of man has been subdivided into a number of major sub-areas (dispersion in air, migration in soil and in vegetation as well as transfer into the food chain, activity distribution in the human organism), enabling an independent analysis, and a relatively synoptic description of the individual sub-areas by means of specific transfer functions. This method permits a largely independent approach to the great variety of individual problems, and a successive adaption to the respective state of scientific knowledge. (orig./HP)

[en] A reevaluation of the current wet deposition models for radioactive plumes of the Gaussian type is presented. The application of the methodology to routine and accidental activity releases from nuclear facilities is discussed. A set of washout parameters for a simplified model has been included

No abstract available

[en] An evaluation of the environmental impact of nuclear plants according to paragraph 45 of the Radiation Protection Directive of the Federal Republic of Germany requires the calculation of dose conversion factors indicating the correlation between the contaminated medium and individual radiation exposure. The present study is to be conceived as a contribution to discussion on this subject. For the determination of radiation exposure caused by the waste air of nuclear plants, models are being specified for computing the dose conversion factors for the external exposure pathways of β-submersion, γ-submersion and γ-radiation from contaminated ground as well as the internal exposure pathways of inhalation and ingestion, which further elaborate and improve the models previously applied, especially as far as the ingestion pathway is concerned, which distinguishes between 6 major food categories. The computer models are applied to those radionuclides which are significan for nuclear emitters, in particular nuclear light-water power stations. The results obtained for the individual exposure pathways and affected organs are specified in the form of tables. For this purpose, calculations were first of all carried out for the so-called 'reference man'. The results can be transferred to population groups with different consumption habits (e.g. vegetarians) by the application of correction factors. The models are capable of being extended with a view to covering other age groups. (orig.)

[en] In connection with a realistic calculation of soil contamination caused by the washout of radioactive nuclides from the waste air of nuclear installations, there arises the question of how to proceed, if, in view of the very time-consuming efforts required for the preparation of sufficiently secured statistics, dispersion-climatological data are available to a limited extent only, such as are required e.g. for safety reports for nuclear power stations. To clarify this question a practicable procedure is presented in this report, which, despite its simplified nature, permits a site-specific calculation of the washout, because it is based on the annual precipitation volumes for the individual sectors of the windrose available for about 80 stations of the German meteorological service. The site-independent data additionally required for calculating the washout are being specified. Following this, the simplified method of calculation is being compared with procedures requiring a larger amount of data. The divergencies resulting therefrom are being discussed. (orig.)

[en] This study discusses the removal of radionuclides from urban construction materials by weathering and forced decontamination. With respect to intermediate and long-term exposure external irradiation due to deposited radio cesium causes the major contribution after nuclear accidents. Therefore, an experimental program was designed and conducted to study the removal of Cs 137 from selected impervious urban surfaces in more detail. The objective of the experiments was to reveal important factors which influence the decontamination process. Particular effort was spent on the investigation of the utilization of ion exchange processes as a forced decontamination technique. The interpretation of the results is presented on the basis of a model which was set up in order to discriminate between the influence of the important physical and chemical processes. The purpose of this description is not only the understanding of the decontamination procedure but mainly the development of better decontamination techniques by a specific manipulation of the relevant processes. (orig.)

No abstract available

[en] CAIRE (Computer Aided Response to Emergencies) - an emergency guidance system - combines actual radiological measurements with mathematical model calculations to obtain a diagnosis of actual radiation exposure within an endangered area. The accuracy of the assessment is nearly always better than one order of magnitude. (author)

[en] The studies have shown that in the case of large transfer coefficients there will result a considerable overestimation of the ingestion dose if nonradioactive depletion effects are neglected. This overestimation may, depending on nuclide, vegetation and transfer coefficient, amount to two orders of magnitude. There will result e.g. for the bone exposure of a grown-up person, caused by ⁹⁰Sr taken up by the consumption of root vegetables, a dose overestimation up to a factor of 50. For the dose to the kidneys of adults by ¹³⁷Cs through consumption of beef there will result an overestimation by a factor of up to 60. And for ¹²⁹I there will be obtained an infant thyroid dose from the pasture-cow-milk pathway being too large by a factor of up to 100. In order to be able to cover these cases by a sufficiently generalized formalism, too, it appears necessary therefore to modify or extend the 'Allgemeine Berechnungsgrundlagen' (German reg. guide for evaluating the exposure from environmental contamination) in the manner proposed in the paper. (orig./HP) 891 HP/orig.- 892 MB