Experimente zur selbsttätigen Abfuhr der Nachwärme bei Hochtemperatur-Reaktoren : Planung, Vorbereitung und Ergebnisse

With appropriate design and dimensions the High Temperature Reactor can remove selfactingly safe the in case of an accident released decay-heat from the core without any technical devices. These important safety features shall be demonstrated in an experiment. The major geometrical and thermal bounderies of such an experiment are derived from the behavior of the HTR-Module in case of a loss of pressure accident. Models for describing the transport of heat through a pebble-bed are evaluated in respect of the experiment giving the heat transfer from the core and the maximum temperatures therin. A preliminary experiment is designed and built. This serves to test components and to study a graphite pebble-bed under accidental conditions. The results of the test runs are compared with numerical simulations and thus allow to validate the computer codes that are used for describing the normal and accidental behavior ofthe reactor. For the demonstrating experiment an appropriate size is derived and a proposal of the design is given. The procedure to simulate the accident is explained