Page 211 - 00. Complete Version - Progress Report IPEN 2014-2016

Nuclear Science and Technology | Progress Report 211

tillation, gross alpha and beta counting, and Internal dosimetry: Routine
thermoluminescent dosimetry are employed.
The workers that carry out activities in areas
The Institutional PMRA has shown over the where unsealed sources are handled are rou-
years that the radiological environmental im- tinely monitored to demonstrate that they
pact of IPEN’s facilities is negligible, as the ef- are receiving adequate protection from in-
fective doses to members of the public are ternal contamination. Direct measurements
several orders of magnitude lower than the of whole-body and thyroid contents provide
recommended levels. an estimation of the radionuclide activity in-
corporated by the potentially exposed work-
ers. These measurements are carried out for
workers, trainees and visitors and are rou-
tinely performed by the In Vivo Monitoring
Laboratory, LMIV. The frequency of measure-
ments is defined by the Radioprotection Ser-
vice (SRP) and the Dose Calculation Group of
IPEN. For this purpose, LMIV are equipped with
two measurement systems: the whole body
counter, NaI(Tl) (8x4”), and the thyroid count-
er, NaI(Tl) (3x3”). The counting room internal
dimensions are 2.6 m x 1.7 m x 1.85 m and
the walls are made with 130 mm-thick steel
sheet lined with 5 mm of lead and 5 mm of
copper. The air is conditioned and the tem-
Figure 14. The renewed sample preparation laborato- perature maintained at 25ºC. The measure-
ry for the characterization of radioactive effluents pro- ment system is calibrated in energy and effi-
duced by IPEN’s facilities, for the execution of the Institu-
tional Environmental Radiological Monitoring Program. ciency, with 152 241 60 sources of Eu, Am and
Co with gamma emissions between 59.54 and
1,408.08 keV, positioned within Alderson Re-
Determination of radionuclides in search Labs anthropomorphic phantom. The
foodstuff and commodities background measurements spectrum is ob-
tained from workers that were not exposed
Several analytical techniques are available and occupationally. The concepts adopted in the
offered in the form of providing services to the HPS N13.30 Standard and proposed in ISO
private sector. Available analyses include: de- documents for standardization are used for
termination of gross alpha and beta activities; activity measurements. The dose calculation
determination of natural and artificial gam- follows the measurements of the activity in
ma emitters; determination of uranium, tho- excreta or in body tissues. The calculation of
rium and radium isotopes; determination of activity in body compartments and the com-
vvvvvvvvvPb and 222Rn; determination of mitted dose estimates are carried out with
radionuclides in foodstuffs and commodities the software “Activity and Internal Dose Es-
imported and exported by Brazil; and deter- timates”, AIDE. These calculations are based
mination of 90Sr in foodstuffs and food com- on the mathematical models recommended
modities; and determination of 3H in water. by the International Commission on Radio-