Fission Chambers for In-Core Use

Fission Chambers for In-Core Use PHOTONIS fission chambers for in-core use can be made to operate at temperatures up to 600°C and up to 20 bar external pressure depending on the reactor types and the detection requirements.  They are critical components for reactor monitoring, and can be used to detect thermal neutrons in high flux, to monitor the reactor fuel burn-up, to control start-up, intermediate and power ranges.

Gas filled neutron detectors are designed to operate in three modes.  Pulse mode analyzes and counts individual detector pulses.  Fluctuation, or Campbell mode, is used to analyze the fluctuation of the direct current from the detector.  Current mode is used to measure the mean of the direct current from the detector.

Fission chambers are filled with the gas appropriate for either high-temperature or fast response, and are  extremely radiation resistant. Depending on the type of fission chamber required, a BNC or HN connector can be mounted on the integrated mineral insulated cable designed specifically for the detector. Fission chambers for in-core use are designed to be movable inside the reactor core during operation. 1.5 mm external diameter, subminiature chambers are available for measurements close to the physical phenomenon.


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