NUCLEONIX SYSTEMS RC 705E Instruction Manual page 38

40Q) If you suspect radioactive contamination in your products, (final or raw materials) what is to be done by you?
A. After, ascertaining that there is a strong case of Radioactive Contamination by measuring with any of the
suggested products, you can approach, Atomic Energy Regulatory Board (AERB) in India or appropriate
regulatory authority in your country for further help & guidance, who will advice, actually after they inspect,
your premises, on what do & how to dispose contaminated material. Please contact Head, Radiological Safety
Division, AERB, (Address given below is for Indian customers)
Contact: Head
Radiological Safety Division,
Atomic Energy Regulatory Board,
Niyamak Bhavan, Anushaktinagar,
Mumbai 400 094.
Fax : 022-25990650
Mobile : 9820864880
41Q) You have mentioned that for clean sample BG reduces by 15% in your user manual. How did you get this
figure? How one should really make meaningful measurements to declare a sample a) Clean, b) Contaminated
& c) Suspected contamination case ?
A) Please understand, all our observations made are based on case studies go through website done by us, for
identification of Radioactive Contamination (RaC) for three situations a) Clean (b) Contaminated or c)
Suspected contamination case. We have clearly mentioned in our case studies, for a clean sample when you
touch the sample, background (BG) reduces from its initial value depending of the thickness/mass of the
material. If the sample is clean as it is preventing natural background entering the probe the reading will fall,
that is the theory.
These case studies were done in Hyderabad, India in Hyderabad BG is 30 µR/hr. we observed this phenomena
of BG reducing by more than 15% for all clean samples. In some other locations/cities, BG could be low and
reduction BG could be 10% to 15%, even in such cases also the material could be clean. For e.g., in case studies
table for sp4 which we have classified as low level contamination, we find that by Radioactive Contamination
Analyzer (Bq/gm System) method Bq/g was found to be 0.076 Bq/g which is a permissible level(<0.1 Bq/g).
Hence this is a relative comparison and a guide for you to make measurements and arrive at meaningful
conclusion. (These are the relative figures). You must understand the logic of making measurements.
Another situation, if it is contaminated to higher levels then reading will go higher than the BG. In which case
you can say that the sample is contaminated. In case of low level contamination, reading may remain same as
BG or it may fall by upto to 7% than BG, then it is a suspected contamination case. So in this kind of situation
it is difficult to identify by Rad check meter some times. May be you can send one kg sample from that heat to
our Radio-analytical lab for detailed analysis by our Radioactive Contamination Analyzer (Bq/gm System)
which will indicate nuclide type that has contaminated & also quantify in Bq/g (This is a fool proof method)
Please go through our case study reports closely as given in the website, from that you will observe in case of
suspected low level contamination the BG fall is relatively less (By 1% to 7.5%). All these case studies were
undertaken by Nucleonix Systems with the interest to help the Steel Industry in identifying & tackling the
radioactive contamination in their products. It is up to you to use this data for your benefit & advantage. We
are not aware whether anybody else has done this kind of case study. You please check up with AERB/BARC
on this subject if you wish to know further. Our studies are to help our customers in using our products to
identify a contaminated sample.
One can notice from the case studies that as % BG fall, reduces contamination levels in Bq/g increase.
Fair conclusions : We can say that if BG falls by more than 8 to 10% by meeting the mass / size criteria to cover
the detector face, then one can conclude that sample is having contamination levels < 0.1 Bq/g which are in
acceptable limits. If the BG falls more than 12 to 15% or above then the sample can be declared as clean.
If BG falls 1% to 8% or remains same as BG then it is a suspected contamination case & if the levels are above
0.1 Bq/g then it is a contamination case.
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