ANALYSIS OF OCCUPATIONAL DOSES FROM THE CDTN REACTOR TRIGA IPR-R1 FOR RADIATION PROTECTION OPTIMIZATION

ANALYSIS OF OCCUPATIONAL DOSES FROM THE CDTN REACTOR TRIGA IPR-R1 FOR RADIATION PROTECTION OPTIMIZATION

Paulo G.M. Maletta1, Adriana M. Guimarães2, Marcos A. Leal1; Tetsuaki Wakabayashi1 and Teógenes A. da Silva 1,2

1Centro de Desenvolvimento da Tecnologia Nuclear, CDTN-CNEN/MG
2Programa de Pós Graduação em Ciência e Tecnologia das Radiações, Minerais e Materiais -CDTN/CNEN
Av. Presidente Antônio Carlos, 6627
31270-901 Belo Horizonte, MG [e-mail] [e-mail] [e-mail] [e-mail] [e-mail] ABSTRACT

Worker and area monitoring have routinely been done around the CDTN TRIGA IPR-R1 research reactor aiming to optimize and assure radiation protection safety. As part of the implementation of the ALARA program, individual doses from planned practices were analyzed. Personnel dose equivalents, Hp(10), from up to 39 occupationally exposed workers were daily reported during their stay in the restricted area. Measurements were done with a RAD-60 Rados electronic personal dosimeter with a 1 µSv low detection limit. Results of about 5000 measurements in a year obtained during 2009 and 2010 showed that monthly doses did not exceed 60 µSv, except in very specific cases of non-routine practices. Results also suggested that values of 40, 100 and 800 µSv could be adopted as weekly, monthly and annual dose constraints. Considering that measured doses were very small when compared to the 20 mSv/year dose limit, it was concluded that the adoption of the dose constraints was enough to assume the compliance with the ALARA principle and that changes in the routine procedure or in the reactor facility design are not needed.

1. INTRODUCTION

Os efeitos danosos causados pelas radiações ionizantes exigiram a criação de um sistema de proteção radiológica adotado internacionalmente, o qual estabelece um padrão apropriado de proteção das pessoas que são expostas às radiações por motivo de trabalho (indivíduos ocupacionalmente expostos), por motivo