[en] Radio-frequency heating of dense plasmas is a central feature of numerous experiments currently being carried out in fusion research facilities the world over. To heat the plasma to a thermonuclear state, microwave transmitters with power outputs of 1 MW at frequencies from a few GHz to more than 100 GHz are required. The only commercially available r.f. tube capable of generating continuous-wave powers of more than 100 kW at frequencies above 10 GHz is the gyrotron. Work is being carried out on the development of a quasi-optical gyroklystron (120-150 GHz/>200 kW) for electron cyclotron resonant heating (ECRH) of fusion plasmas. A prototype of a cylindrical gyromonotron for lower hybrid heating (LHH) at 8 GHz has already been built and successfully tested. The operating principles and design of the two types of gyrotron are described. (Auth.)

[en] In 1985, two identical high-voltage power supply systems were installed in the Juelich Nuclear Research Facility in the Federal Republic of Germany. The systems, which began operation in the following year, supply the energy required by both neutral beam injectors used in the TEXTOR fusion experiment. A new, major feature of the power supply systems is their 68 unregulated, series-connected d.c. sources, connected and disconnected by high-speed electronic switches. With this configuration it is possible to obtain a current of 100 A with a resistive load of 550 Ω (corresponding to a load voltage of 55 kV) in 20 μs, and to disconnect the same current in less than 10 μs. A description of the design and operation of the power supplies is followed by a look at the tests performed by the manufacturer during commissioning of the individual modules. (Auth.)

[en] In fusion research, new applications have arisen for high-power amplifiers in the megawatt range at frequencies up to 100 MHz and above. The power limits of the amplifiers are defined by their final-stage tube, which is subjected to inhomogeneous thermal loading at these frequencies. Theoretical and practical solutions to the associated problems have been found, enabling amplifier design to advance to a new power class. The tube concept is described in detail, as is the experience gained in recent years with a tube installed in a 1.5 MW amplifier. (Auth.)

[en] The Leibstadt nuclear power station was handed over to the customer for commercial operation in December 1984. Due to its exceptional performance the plant's net rating was raised from 942 MW to 990 MW. The authors describe the experience gained during the final construction period, during commissioning and in the first 18 months of operation. The main reasons for the projected cost and schedule being exceeded are discussed, together with lessons learned and conclusions to be drawn for future projects. (Auth.)

[en] Installation of a mirror fusion test facility (MFTF-B) was recently concluded at the Lawrence Livermore National Laboratory in California. In the experiments carried out with this facility, a cylindrical deuterium plasma, confined by a magnetic field, is heated using different methods. One of the methods involves applying r.f. energy to the plasma ions. The r.f. power required is generated by amplifiers based on short-wave broadcasting transmitters. Two such amplifiers have to deliver 1000 kW each for a standing wave ratio up to 1:1.5. Power control, functionality in a magnetic field and an earthquake-proof design are features of these amplifiers to which special conditions applied. The design of these amplifiers is described. (Auth.)

[en] With the start-up of electric power generation by the prototype nuclear power station THTR 300 in November 1985, the pebble bed high-temperature reactor (HTR) has been taken to the threshold of commercial operation. The 300 MWe station was built as a reference plant for the complete HTR line with power ratings from 100 to 600 MW. Cornerstones of the future HTR line are the HTR 500 (electrical rating 550 MW) and the HTR 100 (electrical rating 100 MW) for the generation of electricity and process steam, with the possibility of heat extraction for district heating. (Auth.)

[en] The HTR 100 high-temperature reactor can be used to supply major industrial plants with electrical power and process steam, and local utilities with electricity and heat for district heating. The reactor's standard electrical rating of 100 MW, corresponding to a thermal rating of 258 MW, is available from single-unit power stations or twin plants. Combining the excellent safety characteristics of the high-temperature reactor with those of small nuclear power stations, the HTR 100 is particularly well suited for countries turning to nuclear energy for the first time. (Auth.)

[en] The authors describe superconducting toroidal field coils for a nuclear fusion facility which are part of the Large Coil Task (LCT) project. The coils are wound from cabled, soldered superconductor, mounted in a stainless steel casing and impregnated with an epoxy resin. Multiple sensors are used to test the coil's behaviour during operation. (Auth.)

[en] The Muelheim-Kaerlich nuclear power station in the Federal Republic of Germany is the first of its type and size to be built. Commissioning of the plant, which includes many innovatory systems, was therefore looked forward to with great interest. The pre-operational and hot functional tests were completed in an extremely short time and the reactor became critical for the first time on March 1, 1986. The 100% power tests ended successfully only six months later, on September 9. And on October 7, 1986 the 28-day trial run was concluded without interruption. (Auth.)

[en] Early in 1973 Rheinisch-Westfaelische Elektrizitaetswerk AG awarded the contract for a 1300 MW nuclear power station with pressurized-water reactor, to be known as Muelheim-Kaerlich. Construction of this plant, which began in 1975, was influenced at different stages by many new technical requirements. Only in 1982 could a reliable estimate be made of the completion schedules for the design, manufacturing and assembly work. Non-nuclear commissioning of the plant as a whole began in April, 1985. The article reports on the nuclear power station and its construction. (Auth.)