IONIZATION-CHAMBER ARRAYS FOR NEUTRON-FLUX MEASUREMENTS IN NUCLEAR-REACTORS

The main design principles of channels, intended for continuous neutro n flux measurements in modern defence and protection systems of nuclea r reactors, are considered. Shielded electric cabling arrangement is d escribed for the operation with ionization chamber arrays of the KNI a nd KNU type. The ionization chamber arrays represent combinations of t wo gas-filled fission chambers with different sensitivities to neutron s, and three ionization chambers, of which one is a boron-coated gamma -compensated chamber. The arrays have characteristics matched with the electronic equipment, and are capable of monitoring the thermal neutr on flux within the intervals 1.0-2 x 10(9) and 1.51 x 10(11) cm(-2) s( -1) against a gamma-radiation background, with a relative deviation of the neutron flux load characteristic from linearity not exceeding 2%. The design of a new unit is proposed for measuring the flux density o f thermal and fast neutrons in the intervals 1.0-1 x 10(17) and 1 x 10 (2) - 3 x 10(19) cm(-2) s(-1) in a pulsed reactor.