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The analysis of thorium 232 in worplace materials Thorium 232 analysis



1. To develop a network of European scientists involved in the analysis of radioactive metals in bulk materials.
2. To develop a proposal for the implementation phase (step 2) of a network in order to evaluate the proficiency of the analysis of Thorium 232, investigate sources of error and provide advice to industry and the European Commission concerning the analytical technique and methodology for this analysis.


Thorium is found as a contaminant in some mineral ores used in industrial processes Thorium itself is also used in a large number of industrial applications. It is harmful as it is radioactive and decays to an isotope of lead emitting alpha and gamma particles. The European directive Euratom 80/836 in 1980 requires that Member States oblige employers to report work activities involving materials that have a specific activity of more than 100 Becquels. Many different techniques can be used to measure Thorium 232 but it is not known how proficient these techniques are although a large number of scientific papers have been writen concerning this analysis. The Health and Safety Executive (HSE) in the United Kingdom (UK) has collaborated with the National Physical Laboratory (NPL)(UK) to develop a standard material in order to ascertain how accurately this analysis is performed. Initial evidence from a small intercomparison in the United Kingdom indicates that large errors may be associated with some techniques. Poor measurement quality in public and workplace monitoring may endanger life. The HSE and NPL proposes that a network of European experts is established in order to evaluate the most suitable technique for this analysis and to refine this technique further in order to reduce the errors and develop a standard method for the measurement of Thorium 232 in bulk materials in the Workplace.

Work Content

1. To identify suitable experts in this field of analysis within Member and affiliated European States of the European Community.
2. To gain agreement of these experts to participate in the network and intercompasion analysis of the standard developed at NPL.
3. To create an inventory of current research activities in all member states about Thorium analysis in the workplace and environment.
4. To develop a step II implementation phase proposal for a network to investigate this analysis.


Health and Safety Executive (HSE)
Broad Lane
S3 7HQ Sheffield
United Kingdom

Participants (2)

National Physical Laboratory (NPL)
United Kingdom
Queen's Road
TW11 0LW Teddington
Universiteit Gent
86,Proeftuinstraat 86
9000 Gent