Improvements in individual dose measurement techniques following nuclear emergencies

Abstract

The aim of CONFIDENCE WP2 is to improve the situation awareness in the early phase of a nuclear accident by trying to reduce the uncertainty in individual dose assessment when dealing with external and internal exposures. Main WP2 research actions to improve external dosimetry in this emergency frame were the development of destruction-free protocols using electronic components in smartphones for external dose measurements, Monte Carlo (MCNP) calculations for organ dose assessment with associated uncertainties and the organization of a workshop for integration of biodosimetry into emergency response. On the other hand, one of the main concerns after the release of radioactive material in case of a nuclear reactor accident is the intake of radioiodines in workers and population. A smartphone/tablet application for direct calculation of thyroid doses from monitoring data of the content of 131I (and 132I) in the thyroid was developed during the project (Prototype of processing unit for thyroid dose monitor [IDOSE]). Up to date age-dependent ICRP dose per content values are used by this tool, allowing a rapid screening of exposed persons. A sensitivity analysis on thyroid doses was carried out, considering 16 exposure scenarios leading to 16 different dose estimates, using ICRP56/119 (ICRP60) vs. ICRP130/137 iodine models for adults, varying the time of intake, the time pattern (acute vs. chronic) and considering not well defined relative abundance of short-lived radioiodines and 132Te. Real cases of Europeans contaminated in Japan shortly after the Fukushima NPP accident (low doses), and artificial cases of high doses generated to see the impact of the different parameters in this study, were used for applying this multi-intake scenario approach. Main conclusions of the study are presented here.