Abstract :
The physical principles of nuclear reactors which affect the design of their control and instrumentation are described. Data are presented for the kinetic behaviour of the neutron flux for reactivity changes in a variety of reactor types. The nuclear reactions inherently produce various nuclides, and the effects of these on reactor control and operation are discussed. These nuclides include the delayed-neutron emitters, which cause a slowing down of the reactor kinetic response; ß- and ¿-emitters, which continue to produce heat for a long time after the neutron-reactions producing them have been shut down; and the fission-product poisons. Reasons are given for the system of neutron-flux instruments normally used, and details are given of the principles of design of the various types of instrument.
