Severe accident research activities at Helmholtz-Zentrum Dresden-Rossendorf (HZDR)

In the frame of the nuclear safety research program of the Helmholtz Association HZDR performs fundamental and applied research to assess and to reduce the risks related to the nuclear fuel cycle and the production of electricity in nuclear power plants. One of the research topics focuses on the safety aspects of current and future reactor designs. This includes the development and application of methods for analyses of transients and postulated accidents, covering the whole spectrum from normal operation till severe accident sequences including core degradation. This paper gives an overview of the severe accident research activities at the Reactor Safety Division at the Institute of Resource Ecology.

[Diagnosis of appendicitis in early childhood]

89 preschool children, 2-4 years old, treated under the diagnosis of appendicitis were analyzed, 46 of them were operated. In 40% of those children the diagnosis of an acute nonperforated appendicitis could have been ensured, in 40% the diagnosis of a perforated appendicitis was found, in 20% the laparotomy was negative. In cases of an acute nonperforated appendicitis typical symptoms were vomiting (100%), general stomach-ache (89%) and fever (61%). In most cases of an perforated appendicitis the state of patients was reduced drastically (80%), in 50% an ileus could be observed. Duration of anamnesis was less than 24 hours with all the children who suffered from acute nonperforated appendicitis and with one fourth of the children suffering from perforated appendicitis.

The permeability of large arteries to labeled protein

Using labeled albumin, the permeability index was determined for the aorta and other arteries of the rabbit after different circulation times. The results were reproducible. Different indices of permeability were obtained for different arteries. When the circulation time of the tracer was extended, the increase in the permeability index was greater for the coronary and femoral arteries than for the aorta. 5-hydroxytryptamine, bradykinin and prostaglandin E2 tended to increase the permeability index. There was no relation to the level of blood pressure. The different indices of permeability obtained for the different arteries were not leveled by the mediators. The permeability index is seen to become greater postmortally.

[Permeability of the arterial vessel wall for labeled plasma proteins]

The permeability of the large arteries may be analysed by different methods. It is of different size in the individual arteries and is increased by hypoxia, by hypertension and by mediators. Thus increasedly atherogenic substances may enter the wall of the vessel.