High temp. gas-cooled esp. pebble bed reactor - has gas mixing obstacles at inlet to hot gas outlet ducts

摘要

A high temp. reactor contd. in a cylindrical pressure vessel has downward gas flow and a bed of spherical fuel elements supported on a graphite block structure resting on circular vertical columns forming the hot gas collecting chamber beneath the graphite blocks. The chamber is surrounded by a side reflector and has radial hot gas outlet ducts. To produce thorough mixing of the gases before they leave through the duct thus ensuring that the average temp. of the gases is not greatly exceeded by local hot zones as it enters the subsequent plant, typically a helium-helium heat exchanger or a tube cracking furnace. The height of the displacement object is a specific fraction, pref. one-third, of the height of the columns in the hot gas collecting chamber.