Design of Source Range Signal Amplifier Module for HPR1000 Ex-Core Instrumentation System

The source range channel of the Ex-core Nuclear Instrumentation System ensures the measurement of neutron fluence rate when the nuclear power plant is shut down and at the initial stage of nuclear power plant startup. Because the signal measured by the source range channel is small and the field environment is very complex, the signal collected by the detector needs to be amplified before processing in the source range channel. Therefore, the design of the source range amplifier module is very important. In this paper, a source range signal amplifier module of HPR1000 Ex-core Instrumentation System was designed. The module provides high-voltage power supply for the detector, receives weak signals from the detector, and filters, shapes and amplifies the signals. The anti-interference ability of the module was improved by shielding measures, design of filter circuit and reasonable selection of power supply. The amplitude of the pulse signal from the detector was amplified to the level of the general instrument voltage signal by three-stage amplification. Rapid impulse response was realized through the optimization of component selection. Signal input and output test, accuracy of discrimination threshold test, response time of emergency shutdown test and on-reactor test were carried out on the module. The results show that all indicators of the module meet the requirements of technical specifications.