SYSTEM TO MONITOR BORON-10 ISOTOPE (BORIC ACID) CONCENTRATION

The main function of the NAR-I boron concentration monitoring system based on neutron solution analyzers – automatic continuous measurement of boron-10 (boric acid) concentration in coolant at NPP units with WWER-type reactors.

Composition of NAR-I:

  • main equipment – detection devices (sensors) and data conversion and processing devices (UPO) arranged as follows:
  • NAR-I-N – completed with a UDt-1N mounted sensor (is installed on technological pipelines);
  • NAR-I2-N – completed with a UDt-1N mounted sensor with lower radiation level;
  • NAR-I2-NE – completed with a UDt-2N mounted sensor (includes a hydrogen-containing material shielding from neutron radiation);
  • NAR-I-P – completed with a submersible sensor (is installed in tanks and reservoirs);
  • NAR-I-Pr1 – completed with a UDt-2Pr1 one-channel flow-type sensor with one cuvette connected with a sampling line to a technological system;
  • NAR-I-Pr2 – completed with a UDt-2Pr2 two-channel flow-type sensor with two cuvettes connected with sampling lines to technological systems;
  • NAR-I-K – completed with a UDt-2K control-type sensor (is installed in a laboratory room);
  • NAR-I-N-IS – completed with a mounted sensor and a symbol indicator indicating boric acid concentration in control rooms;
  • NAR-I-P-IS – completed with a submersible sensor and a symbol indicator indicating boric acid concentration in control rooms;
  • additional equipment (forms a part of supply as an option):
  • Am-Be and Pu-Be fast neutron sources;
  • an InS symbol indicator;
  • a URO registration and display unit;
  • an ShT technological cabinet for UPO, URO installation;
  • a container to store and transport fast neutron sources.
 

UDt-1N mounted detection device

Assures measurement of boron-10 isotope (boric acid) concentration in pipelines with diameters equal to 89, 108, 133, 159, 325, 630 mm.

 

UDt-2N mounted detection device

Assures measurement of boron-10 isotope (boric acid) concentration in pipelines with diameters equal to 108, 159, 325 mm (separate versions of UDt for different diameters).

 

UDt-1P submersible detection device

Assures measurement of boron-10 isotope (boric acid) concentration in technological tanks and reservoirs with a protective sleeve with a diameter equal to 120 mm.

 

UDt-2Pr flow-type detection device

UDt-2Pr carries out measurement of boron-10 isotope (boric acid) concentration in sleeves connected with sampling lines to NPP technological systems.

Two versions have been developed: UDt-2Pr1 (one-channel version) and UDt-2Pr2 (two-channel version).

The technological part assures solution flow rate regulation, measurement of flowing solution parameters (pressure, flow rate).

 

UDt-2K control-type detection device

UDt-2K assures:

  • measurement of boron-10 isotope (boric acid) concentration in working standard solutions used for calibration of working mounted, submersible, and flow-type boron meters;
  • measurement of boron-10 isotope (boric acid) concentration in solutions with unknown concentration;
  • determination of a boron-10 isotope atomic fraction in boric acid.

 
  

UPO conversion and processing device

Functions:

  • calculating boron-10 isotope (boric acid) concentration;
  • indicating values in digital and graphical forms;
  • transmitting information via redundant communication links of RS-485 interface and as a current signal (0-5 mA or 4-20 mA) to external subsystems.

 

InS symbol indicator

Functions:

  • indicating current boron-10 isotope (boric acid) concentration in a digital form on panels of control rooms;
  • generating a warning alarm discrete signal.

 

Container to store and transport

A container certified by absorbed dose rate, which is designated to store and transport one fast neutron source (Am-Be or Pu-Be).

The container is manufactured as a cart with a frame (rigidly fixed on it), into which a removable container is installed.

 
Source
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Removable container
Container

URO registration and display unit

Functions:

  • generating NAR-I archive;
  • monitoring operability of all NAR-I devices of a unit;
  • displaying archive data, including boron-10 (boric acid) concentrations in any technological point on a panel computer’s touch screen;
  • checking (calibrating) flow-type NAR-I.

To supply power to a panel computer an MPt power supply module is used.

 
Panel computer
MPt power supply module

  

ShT technological cabinet

Assures possibility to install and connect external communications to UPO or URO. Power cables and signal cables of UPOs are connected to strips of connectors of a ShT cabinet (cables from strips of connectors to UPOs form a part of the system).

Power consumption of ShT with four installed UPO doesn’t exceed 160 W.

Protection degree of ShT – IP23.

System advantages:

  • high accuracy in continuous analysis of boron-10 (boric acid) concentration in process loops of NPP;
  • small equipment readiness time after power-on (not more than 20 min) and output signal setting time by a single abrupt change of concentration (not more than 20 s);
  • absence of additional errors of NAR-I because of influence of external factors (gamma-radiation with absorbed dose rate 0.22 Gy/h, temperature of external environment up to 90 ºС, temperature of measured solution up to 110 ºС);
  • possibility to complete boron meters with Am-Be fast neutron sources with the life of 20 years;
  • provision of possibility of NAR-I operation in accident conditions at temperature of external environment and solution up to 150 ºС (for mounted sensors at temperature of solution up to 265 ºС);
  • testing-confirmed compliance with severe requirements of industrial standards for electromagnetic compatibility, environmental resistance, seismic resistance, vibration and shock loads.

Safety class – 2.
Safety category – А.

Implementation facilities:

  • Rivne NPP, units 1-3
  • Armenian NPP, unit 2
  • Zaporizhzhya NPP, units 1-5
  • South-Ukraine NPP, units 1, 3
  • Khmelnitsky NPP, unit 1
  • Mochovce NPP, units 3, 4

 

SRPA “Impulse” is a leading Ukrainian designer, manufacturer, and supplier of highly-reliable instrumentation and control systems for nuclear power engineering and railways.