NFA-01.05: Criticality Alarm System

The NFA-01.05 Criticality Alarm System (CAS) is required for use in a radio-chemical and for prompt detection and audiovisual alarm annunciation of criticality accidents and to raise an alert for rapid and immediate evacuation of personnel from the affected areas.

  • Detectors:

    Three independent ionization chambers.

  • Criticality Monitor unit, NFA-01.05-11:

    Three independent Criticality Monitor (CM) units measure the dose rate and dose. These modules also include alarm indication and annunciation circuitry. It generates alarm when channel says that dose exceeds 30·10-6 Gy (3 mRad) within a period of 500 ms or the dose rate exceeds 40·10-3 Gy/h (4 R/Hr) in case of fast criticality accidents

  • System Criticality Alarm unit, NFA-01.05-21:

    System Criticality Alarm (SCA) unit generates alarm when two of the three channels indicate that dose exceeds 30·10-6 Gy (3 mRad) within a period of 500 ms or the dose rate exceeds 40·10-3 Gy/h (4 R/Hr) in case of fast criticality accidents. Visual and audio indicators show the operational status (Abnormal, Acknowledged Abnormal, and Normal) of the entire instrument.

  • Each Criticality monitor and SCA shall be provided with battery backup for 8 hours. All the batteries are kept in a separate rack and wired to individual units.

Details

The electronics are enclosed in a splash proof enclosure that is designed to take up a minimum amount of wall space. Installation is as simple as hanging it on the wall and connecting to AC power.