Advanced design high sensitivity boron 10 lined proportional counter capable of operating in high temperatures

For flux monitoring during fuel loading and reactor start- up at fast breeder reactors, high sensitivity boron lined proportional counters are required which can work in 250℃ temperature ambient. High temperature fission counters are available and some of them even operate at a temperature as high as 600℃. Their neutron sensitivities are, however, lower than 1 cps/nv. Boron lined proportional counters can be developed with high sensitivity but such conventional detectors cannot function at high temperatures; their maximum operation temperature is lower than ∼ 120℃. Reference describes the development of boron lined proportional counters capable of operating up to 200℃. However, the authors also describe the observation of break down pulse noise of 0.2 cps value at 200℃. The challenge of operation of detector in high temperatures can be overcome by advanced mechanical design and proper selection of construction material. The present paper describes design and development of a boron 10 lined proportional counter of 15 cps/nv thermal neutron sensitivity capable of operating upto 250℃