부산대학교 도서관

A secondary shutdown device, which must operate if the normal emergency shutdown becomes inoperable, is patented. The device consists of a magazine containing a plurality of neutron-absorbing balls, which are retained in the magazine by a magnetic field. When the magnetic field is de-energized, the balls fall into tubes in the core of the reactor, thereby shutting down the reactor. After the emergency, the tubes containing the balls can be removed from the reactor core, and the balls can be returned to the magazine. Details of the design of the apparatus are described. (M.P.G.)