PURPOSE: To reduce a time for injecting a neutron absorber in a reactor core and improve safety of a nuclear reactor.
CONSTITUTION: A reactor vessel 1, a reactor core housed in the reactor vessel 1, a guide tube 13 inserted from upward in arrangement in parallel with a control rod drive mechanism in the reactor core, a hopper 14 housing a neutron absorber 15 in the inside provided upward of the guide tube, an absorber drop opening 16 communicating with a neutron absorber-injection opening formed in the lower part of the hopper 14, a valve body 17 for opening and closing the neutron absorber drop opening 16, and a drive mechanism 19 for actuating the value body 17 through a connecting rod 18 are provided. At least the lower shape of the hopper 14 is formed in a plane polygon in which the arrangement direction of a plurality of control rod insertion holes is long.
SAITO YUJI
IKEDA TATSUMI
KATAGIRI SHIGEO
TOSHIBA CORP