GB1064382A - Device for regulating the power of a nuclear reactor - Google Patents

Abstract

1,064,382. Reactor control rods. COMMISSARIAT A L'ENERGIE ATOMIQUE. June 15, 1964 [June 25, 1963; Oct. 30, 1963], No. 24697/64. Heading G6C. A neutron absorbing device in the form of a metal chain disposed in a vertical reactor channel has means for displacing it from a withdrawn position, in which it is entirely outside the core, to a deployed position in which it occupies substantially the entire height of the core, and is characterized in that in the withdrawn position it is housed in a detachable container aligned with the channel. The container may be above or below the core; and the chain or chains may be of stainless, boron or cadmium steel. The reactor is graphite moderated, and cooled by CO 2 . The control channel through the top reactor shield 4 has a tubular lining which contains three concrete filled metal plugs 10, 12, 14. Plug 10 houses a winch 24 for handling a cable 26 on which is suspended the absorbing device 90, in this case a plurality of chains 92. The plugs are removable, and are provided with handling grooves 44, 46, 48. Moderator column 58 is lined (62) to provide a control channel 64. The column 58 rests on a core support floor 74 to which is attached a housing 78 for the detachable chain container 84. Orifices 104, 106 are provided in the housing and container to allow coolant flow through both the container and the control channel. A gripping head 96 is fixed to the lower end of the hoist cable and is releasably attached to a chain head 94 by means of cam surfaces on the two heads arranged so that they automatically couple and uncouple (Fig. 4, not shown). To remove the neutron absorber, the chain head 94 is lowered until it rests in seating 98; the loss of tension in the cable releases the coupling and the gripping head 96 is withdrawn into a housing 38. The entire contents of the control channel may now be removed piece by piece (members 10, 12, 14, 66, 62, 86 and 84), and a new neutron absorber inserted. In a second embodiment (Figs. 5, 6, 7, not shown) the container is mounted above the core, and the neutron absorber comprises a single chain controlled by a meshing sprocket arranged above its container. The sprocket and associated driving means may be mounted in either a separate channel plug to that containing the chain container, or in the same plug. In this arrangement, the drive and neutron absorber may be replaced without removing shielding plugs situated below them, thus retaining partial shielding.