Software-based Neutron Flux Measurement Channel (NFMC)

Abstract

For research nuclear reactors such as the TRIGA type, the design of Neutron Flux Measurement Channels (NFMC) has been based, mainly, on discrete digital electronic technology. The work presented here consists of the development of a new version of an NFMC whose aim is to measure the reactor power through six decades using the correlated signal of a wide range fission chamber. The correlation between the Root Mean Square (RMS) value of the detector current fluctuations and the reactor power is known as the Campbell technique, thus leading to the name of Campbell channel. In this new version of the channel, the signal from the amplifier is captured by a fast data acquisition card that sends the data to a computer. Signal processing and visualisation algorithms are implemented by software, thus reducing considerably the number of discrete analogue and/or digital electronic components. This system offers a greater versatility to carry out modifications or replacements of signal processing algorithms and power monitoring sequences. The experimental tests carried out to measure the reactor's power show a very good agreement with the actual power, measured with current measuring channels through six decades of power, obtaining a correlation factor of 99.61%.