Radiological impact on the UK population of industries which use or produce materials containing enhanced levels of naturally occurring radionuclides. Part II: the steel production industry

This report contains an assessment of the radiological impact on the UK population of the steel production industry within the UK. The radiological impact of the primary industry, the waste streams produced and the use of by-product slag have been considered. Individual doses from atmospheric releases from ail currently operating integrated steel plants in the UK are less than 10 μSv y-1 for all age groups. The per caput dose rate in the UK population from 500 years of continuous steel production at the current levels is estimated to be 0.1 μSv y-1. Estimated maximum doses to workers at the steel production plant, landfill workers, and workers manufacturing and using building materials containing slag were generally less than 20 μSv y-1. The estimated radon concentrations in buildings constructed from concrete containing slag depend upon the radon emanation fraction assumed for the material. Experimental data in this area is sparse, and thus a range was considered. The estimated radon concentrations in buildings constructed from concrete containing slag ranged between 7.0 and 10.8 Bq m-3, compared with 9.9 Bq m-3 when slag-free concrete is assumed. The estimated dose from radon exposure ranges between 363 μSv y-1 and 559 μSv y-1, compared with 510 μSv y-1 when slag-free concrete is used. The estimated external dose to an individual in a house constructed using concrete containing slag is 790 μSv y-1 compared with 758 μSv y-1 for slag-free concrete. The overall effect of the use of the slag in building materials therefore ranges between a reduction in dose of 115 μSv y-1 and an increase of 81 μSv y-1. Other scenarios involving exposure of members of the public to slag resulted in doses of less than 5 μSv y-1. The estimated peak individual risk from landfill disposal of steel industry waste is less than approximately 1 10-8 y-1. Currently, radiological controls on the operation of steel production sites are confined to the authorisation by the Environment Agency of atmospheric releases from the sinter plant stacks, under the terms of the Radioactive Substances Act 1993. There are no restrictions on the disposal of solid wastes or the use of slag which relate to their radionuclide content. This position is consistent with the low radiological impact of the industry as presented here. The lack of regulation is also consistent with developing EC guidance in this area. (author)