Attached is a pdf of screening values for release of materials with surface contamination from the draft ANSI/HPS N13.12 Surface and Volume Radioactivity Standards for Clearance.
The radioactivity concentration (screening value) for Cs-137 and Sr-90 is 1 Bq-cm2, which equates to a dose of 1 mrem/yr TEDE.
Accordingly, a 4 Bq-cm2 contamination level on cargo would be about 4 mrem/yr TEDE.
If transuranics were detected on cargo surfaces, the screening value is decreased to 0.1 Bq-cm2, which equates to a dose of 40 mrem/yr TEDE for a 4 Bq-cm2 contamination level.
April 3rd, 2011- NRC PMT – Surface radioactivity screening levels – Pages from ML12094A286 by Enformable
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