Etudes et optimisation des travaux de dragage au moyen de la radioactivité

Study and optimization of dredging works by the means of radioactivity

¹ Port autonome de Nantes - Saint-Nazaire
² Harbour and Engineering Consultant - Haecon
³ Ports Maritimes et Voies Navigables
⁴ Commissariat à l'Energie Atomique

Abstract

Today, the nuclear techniques are tested processes used by the, great modern harbours. • The gamma probes for turbidity monitoring are daily used to determine the navigability depth limit: DAT method (gamma Densimetry Assisted Hydrography. • The radioactive tracers by in situ real scale Lagrangian measurements allow to study the behaviour of the sediments rehandled by the dredging works and to study the recirculation problem, to calibrate models and to define the strategy of the dredging operations. • During the last years, the use of these methods has allowed important economical and ecological improvements by the suppression of unnecessary dredging works, by the optimization of the indispensable ones and by the limitation of the released quantities.