Free-standing domes

The processes that are most suitable for rapid tooling, especially the sintering and melting process (see Section 4.7.3.2), only use as much material as necessary for the production of the component. Isolated geometries as free-standing domes and the like are therefore both produced faster and with less material consumption than with erosive or machining processes. 

Advances in deposition techniques have now made possible the fabrication of free-standing shapes such as the 7.6 cm (3 ) diameter hemispherical dome for IR-window applications shown in Fig. 13.10 which may eventually replace the present IR materials. 

Figure 13.10. Free-standing CVD diamond dome, 7.6 cm diameter, for IR window applications. (Photograph courtesy of Norton Diamond Film, Northboro, MA.)...

The Loviisa NPP, owned and operated by Imatran Voima Oy (IVO), is a unique combination of the nuclear technologies from east and west with the Soviet V -440 reactor and the ice condenser containment (ICC). The Loviisa ICC is a double containment in which the pressure boundary of the containment is the free standing cylindrical pressure vessel with a dome inside the secondary containment. The containment design pressure is 0.17 MPa, and estimated ultimate failure pressure 0.32S MPa. The ice condenser is divided in the Loviisa NPP into two separate sections in contrary to a single ice section in the US and Japanese ice condenser containments. The other significant differences in the Loviisa ICC, compared to the US and Japanese ICC s, are that the total volume of the containment is much bigger, i.e it is of the size of dry containment, there are no air return fans for mixing the atmosphere of the whole containment and the external spray system of the containment steel shell have been installed at Loviisa. 

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