Spectrometer facility for gamma-emitting radionuclide volumetric activity measurement in liquid SGM-101

Purpose:
gamma-emitting radionuclide volumetric activity monitoring in NPP power-generating unit coolant both in stand-alone mode and as a part of computer-aided radiation monitoring system

Spectrometer facility for gamma-emitting radionuclide volumetric activity measurement in liquid SGM-101 (.pdf)

Functions and Features:

  • medium sampling according to specified algorithm using sampling unit valves by LaBr3 crystal-based scintillation gamma-detectors
  • principal identified radionuclide: I-131
  • additionally identified radionuclides: I-132, I-133, I-134, I-135, Cs-137, Na-24, Co-60
  • medium gamma-spectrum measurement
  • measurement unit background radiation measurement
  • measuring chamber rinsing with chemically demineralized water (CDW) and purging with compressed air by means of sampling unit valves
  • medium consumption control by means of sampling unit flowmeters
  • spectrum processing for I-131 specific activity calculation
  • calculated values output to the built-in display or to the upper level, if the unit is connected to computer-aided system
    measured values archiving
  • continuous equipment state control, facility state as a whole and state of individual parts output to the built-in display
  • operator's interface for facility parts operability control, including operability of spectrometric circuit
  • signaling of emergency or warning preset value actuating

 Performance specification

Safety class according to NP-001-97 (OPB-88/97): complies with 3N class requirements

Volumetric activity measurement range, Bq/m3 

3,7x105÷3,7x109

Registered energy range, keV

100÷3000

Permissible relative measurement error limits of radionuclide volumetric activity (confidence coefficient 0,95), %, not more

50

Facility readings irregularity during 8 hours, %, not more

10

Additional error caused by supply variation (-15 to +10), %, of nominal value, or temperature variation (+5 to +50) °C, not more, %

5

Energy resolution
- gamma-radiation energy 122 keV, not more, %
- gamma-radiation energy 1408 keV, not more, %

11,5
3,5

Registration efficiency at total absorption peak for Cs-137 nuclide along 662 keV energy line in specific geometry – the source is in geometric center between detectors, relative units, not less  

0,02

Maximum input detector circuit load, not less, kHz

200

Operating mode setting time for cold detector, h, not more

0,5

AC power supply
- voltage, V    
- frequency, Hz

220
50

Power consumption, V-A, not more

200

Operating controlled medium parameters

 

Controlled medium: water

input pressure: 70 kg/cm2
temperature: (+15 to +50) °C
nonaggressive, chemically low-active

Chemically demineralized water

pressure: up to 10 kg/cm2
Temperature: (+15 to +40) °C

Compressed air

pressure: up to 6 kg/cm2
Temperature: (+15 to +35) °C

Operating environment

temperature: (+20 to +35) °C
Dose rate: up to 10 mR/h

Operating temperature range, C

(+5 to +50) °C  (up to +70 °C during 2 h)

Operating humidity range 

up to 80 % at +35 °C and lower temperature, noncondensing

Operating pressure range   

84,0÷106,7 kPA

Overall dimensions (LxWxH), weight:

Sampling unit:

Sampling rack, not more, mm

1354x704,5x1962; not more than 301,0 kg

Pressure compensator, not more, mm

211x231x3200; not more than 3,5 kg

Lead shielding, not more, mm

542x300x447; not more than 161,0 kg

Protection rack, not more, mm

600x310x660; not more than 53,0 kg

Supply nozzle, not more, mm   

87x99x257; not more than 11,0 kg

Control cabinet units:

Control cabinet, not more, mm  

660x914x229; not more than 31,0 kg

Optical alarm sounder SO-13, not more, mm

70x275; not more than 0,3 kg