BS IEC 61501: 1998 Nuclear reactor instrumentation - Wide range neutron fluence rate meter - Mean square voltage method

This International Standard applies to instrument and measurement channels which generate a
calculation of the mean square voltage (MSV) of a signal arising from a neutron detector, in
order to extract from it information relating to the neutron fluence rate of a nuclear reactor.
After calibration, this information can be used to derive the relative power and the time
constant, for example expressed in terms of period, doubling time, decades per minute or
percent per second.
The method used to calculate the mean square voltage of the signal is also known as
"fluctuation treatment" or "the Campbell method".
Associated with other techniques of measurement, such as pulse rate counting or current
measurement, the calculation of the mean square voltage allows the assembly of a series of
wide range neutron fluence rate measurements for the simplification of nuclear instrumentation
systems in the control of nuclear reactors.
This standard describes the principles, the terminology, the characteristics, the requirements
and the testing methods related to instrumentation and measurement of the neutron fluence
rate using MSV techniques for nuclear reactor control.
Typical examples of the application of the MSV techniques are given.