CAPTURING ROD OF NUCLEAR REACTOR Russian patent published in 1997 - IPC

FIELD: nuclear reactors, preferably on fast neutrons with sodium heat carrier for additional system of device emergency shutdown. SUBSTANCE: device has housing with neutron capturing material which is connected to head by means of hollow pin. Rod is located in directing case which has additional surface in its upper part for hydraulic holding of rod housing in upper position in ascending flow of heat carrier. Additional surface of case is designed as channel over reactor core. Cross section of channel conforms to condition of hydraulic suspension of absorbing rod in upper position for standard use of heat carrier running through case. Cross section of case in region where housing is located in lower position of absorbing rod is greater than cross section of channel over reactor core. Wall of lower part of pin has transmission holes which connect space between housing in lower position of rod and case to inner chamber of pin. Rod head in upper position is not connected to final-control unit. When lesser amount of heat carrier runs through reactor core, absorbing rod is inserted in active core automatically under its weight. This results in reactor shutdown. After firing, absorbing rod is kept in lower position even if amount of heat carrier which runs through case reaches nominal level. EFFECT: increased reliability. 3 dwg