Página 460 - irpa

460 ST 6.1 – Protección radiológica de Trabajadores I (orientada a la industria)
RADIATION DOSES INSIDE INDUSTRIAL IRRADIATION INSTALLATION
WITH LINEAR ELECTRON ACCELERATOR
Lima, Alexandre Roza de1*; Pelegine Queiroz, Samuel1 ;
Alo, Gabriel Fernando 1; Da silva, Francisco Cesar2
1Aceletron Irradiação Industrial. Brasil.
2Instituto de Radioproteção e Dosimetria CNEN, Brasil
* Autor responsable, email: alexandre.lima@aceletron.com.br
Acelétron Industrial Irradiation Company is the unique installation in South America to provide
industrial irradiation service using two linear electron accelerators of 18 kW and 10 MeV energy.
The electron beam technology allows to use electrons to irradiate many goods and materials,
such as hospital and medical equipment, cosmetics, herbal products, polymers, peat, gems
stones and food. Acelétron Company uses a concrete bunker with 3.66 m of thickness to
provide the necessary occupational and environmental radiation protection of X-rays produced.
The bunker is divided in main four areas: irradiation room, maze, tower and pit. Inside the
irradiation room the x-rays radiation rates are measured in two ways: direct beam and 90o. The
rates produced using 10 MeV energy are 500 Gy/min/mA and 15 Gy/min/mA, respectively. For
a 1.8 mA current, the rates produced are 900 Gy/min and 27 Gy/min, respectively. Outside the
bunker the radiation rate is at background level, but in the tower door and modulation room the
rates are 10 µSv/h. In 2014, during a routine operation, an effective dose of 30.90 mSv was
recorded in a monthly individual dosimeter. After the investigation, it was concluded that the
dose was only in the dosimeter because it felt inside the irradiation room. As Acelétron
Company follows the principles of safety culture, it was decided to perform the radiation
isodoses curves, inside the four areas of the installation, to know exactly the hotspots positions,
exposure times and doses. Some hotspots were chosen taking into account worker routes and
possible operational places. A package of three TLD and OSLD dosimeters was used for each
hotspot to get better statistical results. The first results showed that the radiation dose rates are
between 26 Sv/h and 31 Sv/h. This paper presents the methodology to obtain the radiation
isodoses curves and the experimental results.