Abstract: A pH sensitive microsensor which comprises a substrate on which a sensor membrane is formed by laser ablation of a target and depositing the target material on the substrate.

Abstract: A three-dimensional structure of porous silicon considerably improves the anchorage of sensor-active material such as, for example, enzymes, antibodies, etc., on or in the substrate surface of chemical sensors, in particular silicon-based biosensors. This structure is produced by means of suitable etching which forms pore apertures adapted to the penetrability of the sensor-active material. The pore walls advantageously receive a non-conductive boundary layer which consists of oxides of Si and/or Al or Ta or silicon nitride and are preferably 1-100 nm thick. The porous layer is advantageously between 10 nm and 100 .mu.m thick and the pores are preferably in the form of branched ducts whose average diameter is 1 nm-10 .mu.m and in particular 10-1000 nm. The sensor-active material can optionally be distributed in a glass, solid, plastics or polymer membrane.

Abstract: If an emergency arises in gas-cooled nuclear reactor plants having a heat exchanger for removing afterheat due to failure of a blower, the afterheat can be only inadequately removed because of the many deflections and restrictions in a primary circulation loop. In order to achieve adequate removal of afterheat solely on the basis of natural draught, a heat exchanger is located above a top reflector and reaches across a part of coolant gas bores in the top reflector. During normal operation of the nuclear reactor plant, there is a flow of cold gas through the heat exchanger in the direction toward the reactor core and in the event of an emergency, there is a flow of hot gas in a direction out of the center of the core of the reactor. A natural draught coolant circulation is established with the return of the cooled gas through the coolant gas bores in the top reflector.

Abstract: A heat insulation system may protect surfaces along which a hot gas stream is conducted. The insulation may be several plies of slightly compressed ceramic fiber mats, separated by intermediate plates. Cover plates are attached to the hot side. The cover plates are mounted by holding bolts on the support structure carrying the insulation. The support structure may be the liner of a nuclear reactor pressure vessel. Thickness and size of the cover plates are optimized with regard to the stresses occurring at the edges of the holes provided for the holding bolts to ensure dimensional stability of the fiber mats and the functional capability of the metallic mounting system during a long period of time. Several sealing sleeves may be arranged on each holding bolt. In a first solution, some intermediate plates exhibit lug-shaped points stamped out of the plates on both sides in vertical areas of the heat insulation system. The lug-shaped points which transfer the forces of the fiber mats to the intermediate plates.

Abstract: A gas cooled high temperature reactor with spherical fuel elements surrounded by a reflector utilizes at least one ceramic tube and at least one metal tube for removal of pebbles from the core of the reactor. Each cermaic tube is surrounded directly by a ring of graphite columns wherein a plurality of recesses house a number of rod-shaped boron bodies. Additional plate-shaped boron bodies may advantageously be located in the bottom layes of the reflector.

Abstract: It is desirable to being able to vary the temperature of a loop exposed to a flow of hot gases in gas cooled nuclear reactor installations without thereby affecting the gas temperature in the other loops. It should be possible in an extreme case to take the affected loop out of service. This is achieved by arranging under the heat absorbing components in the hot gas channel a means for mixing gas connected with a cold gas line.