Nuclear reactors, applications classification

Hafiiium and zirconium are in the same column of the classification in the periodic table and have hence similar properties except in the nuclear field. Both are associated in the same ore, called zircon, containing only 2-3 % Hf compared to Zr. The production of zircon is abundant 800,000 t/year in Australia (57 %), South Africa (25 %), and other countries. The treatment of zircon leads to the oxide Zr02, zirconia (with 2-3 % of Hf02), which has its own and well-known applications as refi actory ceramics. Electrowinning of pure Zr and pure Hf needs the dissolution of the oxides and their exhaustive separation in advance, Zr being neutron transparent and used as fuel sheath, while Hf is impervious to neutrons and involved in the control systems of nuclear reactors. Carbochloiination in molten chlorides of the oxides leads to ZrCL with 2-3 % of HfCLj. 

The first of these applications, power production, may be further classified according to three specific functions central-station power, package power, and mobile power. Central-station-power applications of nuclear reactors refers to the production of power for large municipal or industrial areas. Package-power applications, however, refer to power production for limited facilities. In this classification, one might include power plants for areas in unusual climatic conditions, advanced bases, or small, isolated establishments. The application of nuclear reactors to power mobile units can conceivably include any device which is designed for terrestrial operation or, for that matter, space craft as well. The possibilities in this area of application are as yet hardly known. 

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