3. Out-of-core instrumentation chains

Out-of-core nuclear instrumentation encompasses all the resources required for instantaneous measurement of reactor power, based on the detection of neutrons leaving the core, and for extracting important parameters such as doubling time, reactivity and, in some cases, axial power distribution, using appropriate processing. The distribution of processing in the classified and unclassified parts of the system is the subject of a fundamental study at the reactor design stage.

The means consist of neutron detectors, cables and electronic modules that can perform analog or digital signal processing.

Generally speaking, the components associated with a neutron detector are referred to as the measurement chain.

The electronic part of an out-of-core measurement chain comprises two main assemblies, as shown in figure...