Holdup Measurement System 4 (HMS4)

Holdup Measurement System 4 (HMS4) 1"Holdup" refers to the accumulation of special nuclear material (SNM) inside the processing equipment of nuclear facilities. Holdup must be minimized and quantified: for radiation and criticality safety, safeguarding against theft or diversion, and economic reasons.

Accurate holdup measurements, while simple in principle, are demanding on the operator. The measurements by their nature are made in situ at specified points in the plant — often in awkward locations where SNM may be deposited, such as valves and ducts. The operator often must wear protective clothing, resulting in additional discomfort during the performance of the measurement under already unpleasant conditions of high temperature and humidity — perhaps up a ladder while holding a detector against a pipe with an outstretched arm. Beside those physical demands, the operator must keep track of the nuclear counting data and associated parameters (e.g., wall thickness, measurement distance).

The HMS4 holdup measurement system makes it all as easy as possible for the operator, who need carry only a small, lightweight mobile unit which guides the operation and automatically logs the data with unique coding. This nearly eliminates the expense of having to repeat a measurement due to a data entry error.
The mobile unit is set up ready to go at the base station. When the operator completes the measurements, the unit is returned to the base to download the data. The host computer maintains all history and current data in an easy-to-use database. All needed reports and QA are available there.

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    ORTEC offers a complete HMS4 holdup system through our Integrated Systems Group which should be contacted for detailed system specifications and a price quote. The system which follows is an example configuration:

    Model Description
    HMS4-SYS-1 Complete HMS4 system consisting of:
    Detector EFC (1X.5/N), Special NaI Detector, description below.
    ORTEC digiDART-R or digiDART with serial communications, includes MAESTRO MCA emulator.
    ORTEC DIM-POSNAI NaI detector bias module.
    Intermec Controller, comprising:
    Intermec CN3 Wireless Mobile Computer (CN3A1A840G5E200)
    Single Dock (871-025-002)
    4 Pack Battery Charger (852-065-002)
    Extended Battery (318-016-012)
    115 V AC Power Supply (851-082-203)
    RS232 CN3 Adapter (850-558-004)
    AC Power Cord (CTG-03130 for US)
    Mini-SD Card 512 MB (856-069-003
    USB Cable, PC to Single Dock (CTG-13172)
    (Equivalents as necessary)
    Host Computer with following requirements:
    Windows XP Professional (or XP Virtual Mode under Windows 7). 
    Printer.
    HMS4-B32 Holdup Software.
    Factory Integration and Test.

    HMS4 Software ONLY
    HMS4-B32 Software for controller and host (supplied on CD-ROM).

    Holdup Detector ONLY
    1X.5/N 1 in.-diameter by 0.5 in.-thick NaI(Tl) integral detector with 1 in.-depth and diameter collimator, 0.320 in.-thick lead side shield, 0.375 in.-thick lead back shield, with Mu-metal shield surrounding front-end electronics. Cable included. Resolution <8% FWHM at 662 keV; weight ~3.8 lbs. 
    1X.5/U Same as 1X.5/N, but with side shield wall thickness of 0.170 in., for measuring low-energy gamma emitters such as HEU; weight ~2.6 lbs.
    1X2/P Same as 1X.5/N, except with 1 in.-diameter by 2 in.- thick NaI crystal, typically used for high-energy gamma emitters such as plutonium.

    Detector Options
    1X.5/HSG Extra housing and shielding to allow for added flexibility, converts 1X.5/U to 1X.5/N.
    1X.5/2/CBL Extra Cable for above detectors with PVC sleeving for easy cleaning.