NFME equipment

Project goals:

  • designing, manufacturing, and implementation of neuton flux monitoring equipment (NFME) at power Unit No. 4 of Kola NPP (Project of reactor plant V-213, reactor WWER-440) in composition of initiating part of emergency protection - engineered safety feature actuation system (EP-ESFAS);
  • confirmation of correspondence of the equipment characteristics to the requirements of relevant Technical Assignments;
  • provision of failure-free operation of the equipment (technical and informational support of operation);
  • monitoring and analysis of NFME operation during operation of the power Unit in order to accumulate the experience of operation and to use it in subsequent developments.

NFME consists of two independent three-channel sets, information presentation devices, set of spare parts, mounting parts and documentation.

Composition of NFME includes the following devices and units:

  • detection device UDPN-01 (detection device on the basis of ionization fission chamber KNK15, range of monitoring the density of thermal neutron flux in the channel of ionization chamber (IC) – from 10 to 1.0106 cm-2s-1 and from 1.0108 to 1.51010 cm-2s-1 at the dose rate  of background gamma-radiation absorbed in the air of not more than 1.0104 Gyh-1 (1.0106 Rh-1) at nominal power of reactor plant);
  • detection device UDPN-02 (detection device on the basis of boron compensated ionization chamber KNK53M, range of monitoring the density of thermal neutron flux in the channel of ionization chamber (IC) – from 1.0·105 to 1.5·1010 cm-2·s-1 (neutr/(cm2·s)) 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;
  • detection device UDPN-03 (detection device on the basis of proportional neutron counters SNM11, range of monitoring the density of thermal neutron flux in the channel of ionization chamber (IC) – from 4.0·10-2 to 4.0·103 cm-2·s-1 (neutr.·(cm2·s)-1) at the dose rate of background gamma-radiation absorbed in the air equal to 1.0 Gy·h-1 (1.0·102 R·h-1);
  • auxiliary unit BH-01 (unit for communication of detection devices with the cabinets of NFME acquisition and processing);
  • auxiliary unit BH-02;
  • data acquisition and processing device UNO-11. It executes the functions of NFME channel:
  1. Calculation of the reactor power and period values on the basis of detection devices’ readings;
  2. Automatic correction of calculated power value (function of automatic correction of power readings (ACPR));
  3. Generation of setpoints for emergency protection (EP) and preventive protection (PP-1) by exceeding of permissible level of reactor power, and permissible decrease of reactor period, generation of signals on exceeding of these setpoints by relevant parameters;
  4. Output of power proportional analog signals to PP-EP ESFAS and automatic power controller (APC);
  5. Generation of setpoints and signals on setpoints exceeding by exceeding of permissible level of reactor power and period to PP-EP ESFAS and APC;
  6. Presentation information about reactivity value on digital indication units;
  7. Transmission of information about power level, period, reactivity, setpoints values, actuation of threshold circuits to representation and recordation equipment (RRE);
  8. Presentation of information of refueling monitoring function on optic-acoustic signaling units of refueling monitoring BSR;
  9. Transmission of power level, period, reactivity characterizing current signals to recorders on block control panel (BCP);
  10. Transmission of power level and period characterizing voltage signals to in-core control system (ICS);