High temp. pebble bed reactor vessel - having rapid shut=down rod insertion tubes

摘要

A reactor vessel, for a high temp. pebble bed reactor, has vertical casing tubes (11), for receiving rapid shutdown rods (12), provided between its cover (3) and its base (4). The casing tubes (11) pref. consist of heat resistant material and have a circular or polygonal cross-section. Pref. the tubes are perforated with openings (13) of smaller cross-section than that of the fuel pebbles. Flaps (14), for protecting the rapid shutdown rods (12) against rising hot material, may be fitted at the upper ends of the casing tubes (11). ADVANTAGE - On rapid shutdown, insertion of the rods is not hindered and destruction of the fuel pebbles is avoided.