Article

An experimental study of detection limits and corresponding doses of IRSN in vivo monitoring vehicles in the case of post-accident scenarios

¹ IRSN/PRP-HOM/SDI/LEDI, BP 17, 92262 Fontenay-aux-Roses, France.
² IRSN/PRP-CRI/SESUC/BSPA, BP 17, 92262 Fontenay-aux-Roses, France.

^* david.broggio@irsn.fr

Received: 18 March 2014
Accepted: 11 June 2014

Abstract

The measurement performances of in vivo monitoring vehicles were studied considering an increase in the radiological background in areas where the population is not evacuated after a nuclear accident. The study focused on ¹³⁷Cs and ¹³¹I Detection Limits (DLs) and corresponding doses, for adults and one-year-old children. These DLs for ground contamination were obtained experimentally using a grid of point sources. Then, the DLs and doses were calculated using the experimental data and a safety factor for two accident scenarios. For these scenarios the ¹³⁷Cs DL corresponds to a committed effective dose of 0.02 mSv. The ¹³¹I DL corresponds to committed equivalent thyroid doses of 3 mSv (adult) and 30 mSv (one-year-old child). To guarantee a 45 mSv thyroid equivalent dose assessment for the child the surface activity of ¹³¹I + ¹³²I + ¹³³I should be below 1.6 MBq/m². This study shows that the vehicles can operate in a contaminated area where the population is not evacuated. However, in such a case, the contamination level outside and inside the vehicle should be kept stable to guarantee efficient body counting.