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The occupational radiation exposure of workers in NPPs during overall maintenance and refueling inspections and decommissioning is determined by numerous parameters. Radiation exposure caused by contamination of components may be minimised by the chemical operation mode and by applying systematic decontamination techniques. Data on occupational exposure in German NPPs as well as information about the radionuclide concentration in the coolant are available. The generic 3D model of the primary circuit presented is based on the analysis of technical documentation of German PWRs. Tasks are modeled as a combination of retention times at related local positions in the surroundings of work areas. The generic model allows the calculation of the resulting occupational doses generated by definable jobs and tasks. The KWU/Siemens-PWR generations are characterised by nuclide vectors, the thickness of shielding, and the material composition of components. It was possible to show that for a pre-Konvoi plant, the calculated occupational dose caused by a specific working task is close to measurements.

This paper deals with boundary value problems of elliptic systems in the plane using W. Wendland's quite general quasinormal form. The usual periodicity condition for boundary data with respect to circulations around the boundary is weakened preserving local continuity of the boundary data and the Lopatinski condition which is satisfied everywhere on the boundary. This yields a half-integer for the characteristic (index) of the boundary condition instead of an integer in the classical case. Beyond that no other values of the characteristic are possible. Using a statement contained in R. Bott's periodicity theorem one can show that, assuming the general validity of the Lopatinski condition, two boundary conditions (with the same system dimension n) are continuously deformable into each other (i.e. homotopically equivalent) if and only if they have the same characteristic. W. Wendland's proof that the boundary value problem is semi-Fredholm remains valid for all boundary data which are periodic in the above-mentioned generalized sense if the characteristic is half-integer. Hence, due to T. Kato's stability theorem, all boundary value problems of the same characteristic γ and fixed system dimension n have the same Fredholm index v. Thus considering an elementary solvable special case one gets the general Fredholm index formula v = n - 2γ, where in the classical case γ is an integer, while the above generalization leads to half-integer values for y. Therefore the additional cases fills the gaps between the classical cases with respect to the Fredholm index v. Finally it is shown that there is an adjoint boundary value problem of characteristic γ*=n-γ Thus its Fredholm index is v*=-v. With respect to both adjoint boundary value problems one has normal solvability.

Zusammenfassung In den vorliegenden tierexperimentellen Untersuchungen an Meerschweinchen wurden die Ergebnisse des Normal lymphocyte transfer-Testes nachBrent undMedawar sowie des Third party-Testes nachWilson, Henry undMerrill auf ihre Zuverlässigkeit bei der Bestimmung der Histokompatibilität von Spender und Empfänger überprüft. beide Teste sind nach den vorliegenden tierexperimentellen Ergebnissen eine Hilfe, aus einem Kollektiv möglicher Spender den für einen bestimmten Empfänger geeignetsten herauszufinden. Als Methode der Spenderwahlerwiessich der Normal lymphocyte transfer-Test dem Third man-Test als überlegen. Die immunologischen Grundlagen dieser beiden in vivo Methoden und die Einschränkungen, die für die Beurteilung ihrer Ergebnisse daraus resultieren, werden diskutiert.