UDPN-01

Detection device UDPN-01 is intended is intended for monitoring of thermal neutron flux density in the channels of ionization chambers at reactor plant operation in start-up (pulse more of operation of detection unit BDPN-01) and in working (current more of operation of detection unit BDPN-01) ranges.

UDPN-01 ensures monitoring of density of thermal neutron flux in initial range from 1 to 1.0·106 cm-2·s-1 (neutr.·(cm2·s)-1), in working range from 2.4·106 to 3.6·109 cm-2·s-1 at the dose rate  of background gamma-radiation absorbed in the air  at the place of detection unit location of not more than 1.0·104 Gy·h-1 (1.0·106 R·h-1) at nominal power of reactor plant (100 %).

 UDPN-01 sensitivity for thermal neutrons in initial range is (0.5 ± 0.1) cm2 (amount of pulses during  1 s at the flux density of 1 neutron via 1 cm2 during 1 s), in working range –  (1.0 ± 0.1)·10-4 cm2.

UDPN-01 sensitivity for background gamma-radiation at exposition dose rate up to 
1.0·104 Gy·h-1 (1.0·106 R·h-1) does not exceed 1.0·10-1 s-1/(Gy·h-1) [1.0·10-3 (pulse·s)/(R·h-1)].

UDPN-01 (UDPN-01-01) consists of:

  • Detection unit BDPN-01, implemented in the form of casing (thin-wall cylinder made of stainless steel), inside of which the chamber КNК15 is located. BDPN-01 converts neutron radiation into current pulses (at great values of neutron flux density - into current).

The appearance of detection unit BDPN-01 is presented on the picture: 

The appearance of detection unit BDPN-01
  • Conversion unit BPH-01, implemented in the form of flat housing, inside of which the electromagnetic shield with electronic modules is located. BPH-01 performs the following: 
    • amplification of current pulses received from BDPN-01;
    • discrimination of noise pulses;
    • generation of output pulses with the frequency proportional to neutron flux density (at UDPN-01 operation in initial range);
    • conversion of current from BDPN-01 into succession of voltage pulses which frequency is proportional to neutron flux density (at UDPN-01 operation in working range).

The appearance of conversion unit BPH-01 is presented on the picture:

The appearance of conversion unit BPH-01

UDPN-01 is built-up on the basis of ionization fission chamber KNK15 with thermo-radiation stable cable with magnesia insulation (KNMMS). Length of BDPN-01 cable depends on design of detection unit.

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