NFME equipment

Project goals:

  • designing, manufacturing, and implementation of neuton flux monitoring equipment (NFME) at power Unit No. 1 of Novovoronezh NPP-2 (Project of reactor plant V-392M, reactor WWER-1200) in composition of control and protection system of  power Unit;
  • 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 and industrial seismic protection system (ISPS) 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 four-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 (ссылки на соответствующие места раздела «продукция») (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-04 (detection device on the basis of helium corona counters of neutrons SNM18-1, monitoring range of thermal neutron flux in IC channel – from 3.010-3 to 5.0102 cm-2s-1 (neutr.(cm2s)-1);
  • detection device UDPN-05 (detection device on the basis of boron compensation ionization  chamber of hypersensitivity KNK17-1, range of monitoring the thermal neutron flux in IC channel –from 1.0104 to 2109 cm-2s-1 at the dose rate of background gamma-radiation absorbed in the air equal to 1.0104 Gyh-1 (1.0106 Rh-1);
  • detection device UDPN-06 (detection device on the basis of boron neutron counter CPNB44 (Photonis SAS, France), range of monitoring the thermal neutron flux in IC channel –from  5.010-2 to 1.0104 cm-2s-1 at the dose rate of  background gamma-radiation absorbed in the air of not more than 10.0 Gyh-1 (1.0103 Rh-1) ;
  • detection device UDPN-07 (detection device with the in-core location of IC on the basis of fission chamber KNK15, range of monitoring the thermal neutron flux – from 1.0 to 
  • 1.0106 cm-2s-1 (neutr(cm2s)-1) at the dose rate of  background gamma-radiation absorbed in the air  at the place of BDPN location of not more than 1.0104 Gyh-1 (1.0106 Rh-1);
  • auxiliary unit BH-01 (unit for communication of detection devices with the cabinets of NFME acquisition and processing);
  • data acquisition and processing device UNO-06. It executes the functions of NFME channel:
    • Calculation of the reactor power and period values on the basis of detection devices’ readings;
    • Automatic correction of calculated power value (function of automatic correction of power readings (ACPR));
    • Generation of setpoints for emergency protection (EP) and preventive protection (PP) 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;
    • Generation of setpoints and signals on setpoints exceeding by exceeding of permissible level of reactor power, and permissible decrease of reactor period  for automatic reactor power controller (ARPC);
    • Calculation of reactivity value (RMI function);
    • Monitoring of neutron flux density and speed of its change during refueling of nuclear fuel, generation of setpoints by permissible level of the flux density and speed of its change, generation of signals on exceeding of these setpoints by relevant values (RMS refueling monitoring function);
    • Monitoring of neutron flux density during the first loading of nuclear fuel (PSE physical start-up monitoring function);
    • Generation and output of discrete and analogue signals to adjacent systems;
    • Output of information to information presentation devices, located in main control room and in emergency control room, at the panels of refueling machine and of physicist on duty.
  • emergency protection setpoints setting unit (BKC). It is located in the main control room;
  • data acquisition and processing device UNO-09. It executes the functions of data acquisition and accumulation (achieving) device - DDLH. It ensures data acquisition and support of achieve on operation of intrinsic NFME set. It ensures output of information on operation of intrinsic set channels to monitoring, control and diagnostic system (MCDS) and to top level system of Unit (TLS-U) from independent gateways via fiber-optic communication lines;
  • information presentation devices of MCR and ECR, panels of refueling machine and physicist on duty (digital indication units BIC, optic-acoustic signaling units of refueling monitoring BSR, operative displays);
  • reactor internals state monitoring hardware (RISMH). It executes the functions of spectral analysis of readings of detection devices, and calculation of parameters of axial vibrations of the reactor vessel. 

Structural diagram of NFME set:

Структурная схема комплекта АКНП Список сокращений

NFME interconnection with the adjacent systems is performed by means of standard unified interfaces by discrete signals, analogue signals, data flows. NFME channels ensure the galvanic separation of input and output signals, as well as galvanic separation of signals between the units inside NFME itself. NFME TM have a reserve by input and output signals.

To ensure the reliability of functioning NFME is provided with automatic diagnostic of state of technical means, and with manual automated channel diagnostic.

To decrease the probability of failures by common cause NFME is provided with realization of algorithm for calculating the power and period by two different methods in each NFME set. Different libraries of mathematical functions, different drivers of data exchange components are used. NFME software, participating in execution of emergency protection functions, is realized without use of operational system, which rules out the possibility of software failure due to errors of exchange functions, functions of diagnostic and system loading.

The design and technical solutions taken ensure the safe for life and health of personnel technical maintenance of NFME at keeping of the requirements specified in design and accompanying documentation.