[ RadSafe ] Instruments to certify exporting equipment clean

Robert J Gunter rjgunter at chpconsultants.com
Thu Apr 21 11:38:40 CDT 2011

Greetings Peter et al,

My company has supplied instruments and am working on a procedure for
exactly this purpose.  Basically we have recommended a Ludlum Model 2221
paired with a Ludlum Model 44-10 NaI probe.  This meter and probe
combination is very capable of assessing natural background radiation.  Of
course the background can change based on what you may be assessing.  For
example, if you are shipping KCl, the Postassium (K) has a relatively high
background due to naturally occurring K-40 isotope.  So you would want to
have an unimpacted (pre-release) sample to use as your background if you are
assessing something that has a relatively high concentration of naturally
occurring radioactive material.

We are nearly out of 44-10 probes but can get new ones.  We have a large
number of the Ludlum Model 2221 meters for $1250 each (these are used but
fully functional, Ludlum Instruments sells them new for double that price).
We sell 44-10's for $560 and have two left.  Ludlum charges $1036 each for
them.  We also sell the cable to connect the two for $30 each.  The
advantage of the Ludlum Model 2221 is it has both a scaler and a ratemeter
function.   This lets you document your daily background with a timed count.
You can use this as a reference for counting your samples.  We tell our
clients to assess further if the reading is 2X background.  This is
basically a quick screening method that does not quantify anything.  We
suppose that you will not likely find much and if you do, you would perform
a more detailed analysis to determine if it is safe to ship the product.
The NaI detector is far more sensitive when applied directly to the drum or
container than any Ports radiation monitor is likely to be.

The NaI probe is very sensitive and appropriate for what you are looking to
assess (Mixed fission products).




Robert J. Gunter, MSc, CHP

CHP Consultants/CHP Dosimetry



Toll Free: (888) 766-4833

Fax:  (866) 491-9913 

Cel:  (865) 387-0028

rjgunter at chpconsultants.com


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