GB1070572A - Nuclear reactor control mechanism - Google Patents

Abstract

1,070,572. Controlling reactors. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. May 25, 1964 [May 29, 1963], No. 21569/63. Heading G6C. A control element of a water-cooled nuclear reactor which is formed of a boron steel cylinder, is hydraulically retracted from the core or extended into it by a spring. The element may be given a continuous axial movement for rapid insertion into the core of a stepped movement from a latch and rack escapement. Three separate and adjustable fluid supplies provide the control; one to effect the element axial movement, one to operate the escapement and one to adjust a slide valve which determines whether the element movement is continuous or stepped. To give the element the stepping motion i.e. fine operational movement, the escapement is reciprocated by the intermittent interruption of the escapement fluid supply. For emergency rapid insertion of the element, the fluid supply pressures are adjusted so as to separate the escapement from the element and so place the element under spring control. The control mechanism is immersed in the reactor coolant, the rack is mounted on the control element itself and the latch members are mounted on a tube surrounding the element and are movable with respect to the reactor and element. In a second embodiment the rack is mounted on a separate extension fixed to the control element and the latch members mounted on a tube fixed to the reactor.