The THTR-300 - an opportunity missed?

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Approximately thirty years ago, construction of the thorium high-temperature reactor (THTR-300) was started in HammUentrop. A new epoch in generating nuclear power was to begin, as this reactor line cooled by helium gas, was to be used not only for electricity generation, but also to supply high-temperature heat for a variety of uses. Accordingly, the federal and state governments together with the group of operators supported the development of this line. High-temperature reactors of the THTR-300 concept are characterized by these features: integrated design of the reactor pressure vessel; high safety and technological advantages of the reactor concept employing graphite fuel spheres and helium as a chemically inert primary coolant; high inherent safety as a result of the overall concept; optimum thermodynamic parameters of the high-efficiency water-steam cycle. The construction and operation of the THTR-300 suffered from a number of obstacles in the forms of licensing technicalities and licensing policy, which caused major delays in completion. In the absence of any perspectives of continued operation, the shareholders decided to decommission the plant in 1988. After the first partial construction permit in 1971, a total of 16 partial construction permits with 21 supplements and 1 350 new conditions had been considered necessary by the licensing authority up to the date of full commissioning. The planned delivery period of approx. 60 months thus grew to almost 200 months. As a consequence, the original costs of construction of approx. EUR 350 million rose to approx. EUR 2 050 million. Valuable experience was accumulated in the 16,410 hours of operation of the THTR-300. On the whole, the concept turned out to be excellent, also thanks to the commitment of all participating scientists, engineers, and economists.

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Gasification and partial gasification of coal in connection with combined processes for the generation of electricity and heat in combination with nuclear energy would result in conversion processes especially favorable from the energetic point of view. The author describes the steps on the way to this objective.
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