Radiation monitoring of raw material and waste at steel plants in Mariupol

The Azovstal integrated steel works and Positron, a firm established in Germany and Ukraine, have jointly introduced the 'Kordon' system for checking the radiation quality of raw material on delivery to Azovstal. Sensors installed on rail weigh bridges measure in real time the gamma background of raw material adjacent to the walls of passing rail wagons. As for finished products and production waste, continuous radiation monitoring for the purpose of detecting abnormal concentrations of natural radionuclides is carried out by Azovstal's own radiation safety service, air and water pollution control laboratory and radioactive isotopes laboratory and by STAKS, the Mariupol radiology centre. Gamma-spectroscopy analysis of more than 60 types of raw or semi-finished material, final products and waste has identified the materials representing the greatest radiation hazard. These include: potash, potassium nitrate, zirconium ladle nozzles, 'bakor' and other types of refractory. The shops where these materials are employed, as well as shops where radioisotope sensing devices are used, have been classified as facilities with an increased radiation hazard. Research showed that the zirconium nozzles potentially present the greatest danger. Consequently, all the types of waste arising during their life-cycle were examined for radionuclide content. This revealed that dumping of zirconium-containing waste can create local radiation hot spots. To prevent this, spent nozzles are now melted down in the oxygen converters. This has not caused any exceeding of the critical value for converter slag radionuclide content: slag radionuclide content has remained at no more than 340 Bq/kg, and the slag therefore continues to be suitable for use in any type of construction work. Air sampling and analysis for total alpha and gamma activity has shown that the dumping of waste from Azovstal has no adverse effect on the radiation situation within the plant or in the adjoining areas. The STAKS centre is developing, with municipal funding, a system for radiation monitoring of the city of Mariupol using modern gamma tracer devices from Positron (Germany). The above example of interaction between works and municipal radiation safety services is illustrative of a common problem at the present stage of development of radiation monitoring in Ukraine. Up-to-date equipment enabling data to be collected, stored and processed at minimal cost is available, but it is employed in uncoordinated, piecemeal fashion. As a result, the accumulated data, which is of great scientific and practical interest, is used inefficiently. Furthermore, the development of environmental management systems requires the inclusion in the databases of information on questions such as the concentration of pollutants in the air and water, the local climate, etc. These requirements cannot be met for large regions without the development of coordinated standard metering techniques and data exchange protocols; the use for information transfer of existing global computer networks, and the fitting of measurement devices with network interfaces enabling them to be linked directly to network servers. These matters can be resolved only in coordination with all the interested environmental organizations. (author)