Abstract Control rod assembly for nuclear reactors includes a plurality of finger control rods carried in common by a spiderlike holder, mechanical drive mechanism for displacing the holder vertically to insert the finger control rods into a plurality of fuel elements, the finger control rods containing neutron-absorbing substance along at least part of the length thereof, means for mounting a plurality of neutron-absorbing shutoff rods outside the reactor core, the mounting means being releasable during abnormal operation of the reactor for inserting the shutoff rods into the fuel elements and entrainment means operatively connected to and displaceable with the finger control rod holder and entrainable by the entrainment means in released condition of the mounting means.
Control rod assembly, according to claim 1, wherein said drive mechanism is actuable for upwardly displacing said finger rod holder and said shutoff rod-mounting means through said entrainment means, and wherein said entrainment means are spring mounted on said finger rod holder, and form a force-locking connection with said shutoff rod-mounting means only when the latter is being upwardly displaced.
Claim 2
Dependent Claim
33 words
Control rod assembly according to claim 2, wherein said shutoff rods are connected by a bridge member, respectively, in groups of four shutoff rods defining spaces therebetween wherein said entrainment means are received.
Claim 3
Dependent Claim
42 words
Control rod assembly according to claim 1, wherein said shutoff rods are releasable remotely from said mounting means thereof for dropping by force of gravity together with other control rods of the reactor into the reactor core for shutting down the reactor.
Claim 4
Dependent Claim
28 words
Control rod assembly according to claim 4, including spring means operatively connected to said shutoff rods for accelerating the dropping of said shutoff rods into the reactor core.
Claim 5
Dependent Claim
53 words
Control rod assembly according to claim 3, wherein a plurality of said groups of shutoff rods are assembled in separate units, each of said groups being insertable in a separate fuel element, said spiderlike holder having separate entrainment means for entraining a separate mounting means for a corresponding unit of assembled shutoff rods.