Investigations of radiological impact of accidents under probabilistic aspects

A new concept of atmospheric dispersion modelling of UFOMOD has been developed. The new code consists of two parts: the near range model using MUSEMET or RIMPUFF to calculate emergency actions and early fatalities and the far range model using MESOS (ICST, UK) to assess late health effects and long term countermeasures. An important part of work has been focussed on updating the computer code UFOMOD with respect to the dose calculations for external exposure and for internal exposure from ingestion. To assess the stochastic somatic health effects, new age- and sex-dependent dose-risk conversion factors are now being implemented in UFOMOD. The data were provided by the GSF and are based on either a relative or an absolute risk model, dependent on the type of the effect. Linear and linear-quadratic dose-risk dependencies will be applied for leukemia and cancers of the bone surface, thyroid, lung, GI-tract and other organs. The revision of the foodchain part of UFOMOD has been almost completed in the reporting period. (orig./DG)