NEUTRON FLUX MONITORING SYSTEM
The AKNP-IF neutron flux monitoring system is a part of a control and protection system (SUZ) of NPP units.
Functions of AKNP-IF:
- monitoring, continuously registering, and archiving current values of reactor relative physical power, velocity (period) of its change, and reactivity;
- generating discrete signals on exceeding emergency and preliminary protection setpoints, setpoints of control and regulation by relative physical power and period for SUZ and unit’s I&C subsystems;
- presenting analog and discrete signals in the optical and acoustic form to operators of main, backup control rooms and a fuel reload machine, to operating personnel;
- automatically correcting neutron power measurements taking into account thermal physic and other parameters characterizing state of a reactor facility;
- monitoring fixation of in-core devices by results of neutron detector signal fluctuation analysis;
- monitoring subcriticality of a reactor facility.
Composition of AKNP-IF:
- two sets of AKNP-IF APZ-SKP for SUZ and a main control room;
- one set of AKNP-IF BCR for a backup control room.
Each set includes three independent channels of neutron flux monitoring. Each neutron flux monitoring channel consists of:
- detection devices containing:
- detection units based on ionization chambers (for startup and operating ranges), on boron or helium corona radiation-resistant highly sensitive neutron counters (for an SKP fuel reload monitoring system);
- amplification and digital conversion units;
- an accumulation and processing device;
- a device for input of power setpoints;
- registration and display units for a main control room and a fuel reload machine panel to display and archive current parameters, as well as to transfer information to unit’s adjacent systems – common for three neutron flux monitoring channels.
and working rangesв
Detection unit for SKP
- automation of calibration of neutron flux density monitoring channels during operation of AKNP-IF using a metrologically certified reactor kinetics simulator developed by SRPA “Impulse” (signals are simulated in a whole range of neutron flux monitoring without necessity of access to sensors in a restricted zone);
- high accuracy due to use of highly sensitive boron and helium neutron sensors;
- integration of a fuel reload monitoring system into AKNP;
- absence of influence of residual readings of detection devices after power operation due to use of fluctuation mode of an ionization chamber;
- possibility of operational calibration of power readings in MCR with automatic recalculation of calibration coefficients;
- high fail-safety of the system due to use of redundant hardware and diverse software.
Safety class – 2.
Safety category – А.
- Zaporizhzhya NPP, units 1-6
- Khmelnitsky NPP, units 1, 2
- Rivne NPP, units 1-4
- South-Ukraine NPP, units 1-3
- Armenian NPP, unit 2