The Co-ordinated Research Project (CRP) on Radiotracer Technology for Engineering 
Unit Operation Studies and Unit Process Optimization was carried out by the International 
Atomic Energy Agency (IAEA) from December 1997 until December 2000. The project 
developed and validated procedures and protocols for investigation of major industrial 
processes, including fluidized beds, sugar crystallizers, trickle bed reactors, cement rotary 
kilns, flotation cells, grinding mills, incinerators, wastewater treatment units and interwell 
communications in oil fields. 
Over the years, the IAEA has contributed substantial funding and effort to industrial 
applications of radiotracer technology. Significant progress has been made, enabling IAEA 
Member States to introduce the technology in well defined industrial processing fields and 
establish national and private radiotracer groups with the indigenous capacity to sustain and 
further develop the technology. There are currently more than 50 radiotracer groups in the 
developing Member States of the IAEA applying radiotracers in routine service to end users. 
This publication is the output of the above mentioned CRP. It provides the principles and 
state of the art of radiotracer methodology and technology as applied to industry and 
environment. It is expected to provide wider interest for further development of skills and 
confidence prior to carrying out field work. It facilitates transfer of technology from 
developed to developing countries and from nuclear research institutions to industrial end 
users. The publication could be a suitable guide for radiotracer applications in almost all types 
of process investigations. The case studies described in this publication deal with typical 
problems in industry and environment common to all countries. It is intended for radiotracer 
groups as well as for end engineers and managers from chemical and petrochemical industries, 
mineral ore and raw material processing, wastewater treatment plants, and other industrial 
sectors.