Automatic Reactor Control Systems

Two types of servo-system for the automatic control of nuclear reactors are considered. In the first, the detector follows the displacement of some point, e.g. a point of fixed neutron flux. This arrangement is suitable for measuring the period, power and degree of sub-criticality, and for triggering emergency shutdowns. In the second type the reactor power is made to follow in a certain way the displacement of the detector. The latter system can be used to control the approach to criticality and to adjust the period and power. By combining servo-systems of both the foregoing types into a single scheme, control equipment of a more complex type can be built up. It is found that two types of automatic control system emerge. One of these is introduced comparatively easily into existing installations; the other is more advanced and probably is more suitable for future designs. The advantages of the systems put forward are that they employ simple standard units, are self checking and ensure that the operating conditions of the detector and its ancillary apparatus are kept constant.