Wiederaufarbeitung von Kernbrennstoffen

Reprocessing of spent nuclear fuels . The present waste disposal concept for nuclear power plant requires the rapid construction of a reprocessing plant in the Federal Republic of Germany, with the location still being uncertain (Bavaria or Lower Saxony). The task of such a plant will consist in recovering usable nuclear fuels and processing them to new fuel elements. Waste materials are prepared for final disposal. The components of the plant are presented with their design data, associated development plans are discussed, and changes with respect to former plans, in particular the maintenance concept, are outlined. The article also reports the present status of the licensing procedure and current planning.     

Modultechnik — Zielsetzung,Aufbau, Konsequenzen und Erprobung

Modular technique: objectives, layout, test facility . In spent fuel reprocessing plants the hot process cells cannot be entered by the personnel without intensive decontamination of the cells and the equipment. In the German reprocessing plant the FEMO technique (i. e. remote handling modular design) is used to achieve high plant availability and to reduce the radiation burden of the personal. The characteristics of the FEMO technique are two canyon cells in which the process equipment is installed in standardized racks arranged on both sides of each cell. The unit of process equipment and rack is designated as the module. This article reports the objectives of the modular technique, the resulting layout, and the test facility program to confirm this maintenance concept.     

Technical aspects of extraction of platelet concentrates from dogs with an automated cell separator

The results of this work point out that the cell separator AS 104 (Fresenius AG, Bad Homburg), which is developed to obtain platelet concentrates from human beings, can be used for dogs. The base adjustment of the cell separator for human beings (adjustment I) is useful, because of the high yield [platelet count (median): 1.75 x 10(11)] and quality [low leucocyte- (40/microliter) and erythro count (10 x 10(3)/microliter)]. In addition, there was no clear difference between the base adjustment (adjustment I) and an empirical modification (adjustment II). The platelet count of the donor dog decreased during the separation by approximately 140,000/microliter and reached the initial value after four days. Supplementary, the time course of the haematocrit and the concentrations of albumin, total protein and total calcium of the donor dog were measured. It should be mentioned that the concentrations of ionized calcium distinctly decreased during the separation. Synchronously, the concentrations of ionized calcium and of citrat reached the starting-counts 3-4 hours after the ending of the separation.     

Disseminated intravascular coagulation and hyperfibrinolysis in dogs with metastasizing mammary carcinoma

The alterations of the haemostatic system (platelet count, activated partial thromboplastin time [APTT], thromboplastin time [standard test, modified test], thrombin time, fibrinogen concentration, activity of the coagulation factors II, V, VII, X, VIII:C, IX, XI, XII, of prekallikrein, high molecular weight kininogen, antithrombin III, protein C, plasminogen and alpha 2-plasmin inhibitor, concentration of soluble fibrin and fibrin(ogen) degradation products [FDP], resonance thrombogram) were described in seven dogs with haemorrhagic diathesis in consequence of an infiltrative, growing mammary carcinoma with multifocal invasion of lymphatic and blood vessels. In most of the cases metastases in different organs could be demonstrated. In every case a serious stage of disseminated intravascular coagulation and hyperfibrinolysis was existent. This was indicated by the distinctly increased concentration (p < 0.0001) of soluble fibrin (27.7 [16.0-79.2] micrograms/ml, median [minimum-maximum], reference range [RR.]: < 9.4 micrograms/ml) and FDP (340 [50-860] micrograms/ml, RR.: < 18 micrograms/ml) as well as a diminished plasma level of nearly all components of the coagulation and fibrinolytic system concerning especially the concentration of fibrinogen (0.16 [0.01-0.46] g/l, RR.: 1.17-3.09 g/l), the activity of factors V (30 [21-40]%, RR.: 75-158%) and VIII:C (9 [4-16]%, RR.: 72-136%) as well as the activity of protein C (8 [3-13]%, RR.: 68-139%) (each: p < 0.0001).     

Sensitivity of resonance thrombograms in thrombocytopenia of dogs

Based on results of 84 blood samples, taken from 28 dogs suffering from thrombocytopenia, the resonance thrombography turned out as a method with low sensitivity (S) to detect thrombocytopenia in dogs. It was insignificant which one of the two tested resonance thrombographs was taken for measurement and which parameter of the resonance thrombogram (RTG) was used for the thrombocytic potential of haemostasis, the amplitude (RTG-P) or descending time of the platelet side. Only samples containing < or = 25,000 platelets/microliter were reliably measured (S > or = 0.90), whereas thrombocytopenias with > 50,000 platelets/microliter usually resulted in false negative results. The correlation between the platelet count and RTG-P could be almost expressed by a geometrical regression (rs = -0.709). The low sensitivity of RTG mirrors the multifactorial influences and contrasts to the exclusive use of RTG in the screening of thrombocytopenia.     

Investigation of the structural behaviour of nuclear spent fuel reprocessing plant components subjected to dynamic loads

In the planned reprocessing plant for spent nuclear fuel elements in Germany components and systems, which form a process-technical unit are integrated in a steel structure called a “module”. In the present paper, the stability and strength of two representative modules under dynamic loading due to earthquake are investigated. Since full scale models of the modules exist, both analytical and experimental investigations are possible. The results of the two investigation methods are in good agreement. Both modules withstand the earthquake loadings with only minor modifications.     

Vibration isolation of a building against earthquake, airplane crash and blast

The influence of three different support concepts on the vibration responses of a building to the load cases earthquake, airplane crash and blast is numerically investigated. Compared are the three concepts: the standard version of a double shell structure with a combined base for inner and outer building without isolation system; the same building with isolation system between foundation slab and soil, as vibration isolation known so far; and as a third concept a double shell structure with completely separated inner and outer building, where the isolation system is placed between the two parts of the building. The results show that, compared to the standard concept, the third concept leads to a nearly complete isolation of shock-induced vibrations, and to a reduction of the vibrations caused by an earthquake, comparable to the reduction in the isolation concept known so far.     

Control strategy for an icebreaker propulsion system

The latest series of Canadian Coast Guard ice-breakers features a diesel electric propulsion system using synchronous motors and synchronous generators. The synchronous generators supply power to a constant-voltage 60 Hz bus that feeds the ship's hotel load and the propulsion system's cycloconverters. The cycloconverters convert 60 Hz AC power to variable frequency 0-18 Hz AC power for the synchronous propulsion motors. The propulsion motors are directly connected to the ship's propellers by means of shafting. This AC-AC propulsion system realizes the `power plant' concept, which optimizes the number of generators that are online in order to match the generated electrical power to the total electrical demand of the ship. The propulsion control system has two control loops that limit the power delivered by the propulsion motors to prevent the diesel engines, which drive the generators, from stalling during instantaneous or sustained overloads