Management of particles detected on the Dounreay site

Much effort is involved in finding and retrieving historic particles from the environs surrounding the Dounreay nuclear site. Historic particles are also present on the site itself, and these are dealt with as part of the ongoing contaminated land management regime. UKAEA operates systems of routine monitoring on outside surface areas in order to limit exposure to the workforce under the Ionising Radiation Regulations 1999. Contaminated material is removed when found, and this material undergoes separation and analysis routinely and where suspected to contain a particle. Information regarding on-site particles has been built up as a result of this. The distribution of on-site particles provides details of the likely dispersion pathways, and it is apparent that some interaction occurs between the on-site and off-site particle transport mechanisms. The strategy for dealing with contaminated land at Dounreay is to manage contamination in situ during the decommissioning phase, where the risk of doing so is acceptable. Particles present a very low risk to Dounreay site workers but it is considered ALARP (as low as reasonably practicable) to detect and remove these particles. The particles are a legacy issue arising from historic practices, which would not meet today's safety standards. A continuing programme to detect, remove and record their presence will be required during the site closure process. This will be necessary to meet current regulations and the likely criteria for releasing the site for future re-use. The final solution for the particles will not be known until the Best Practicable Environmental Options study is completed and further development of the site end-point work has been reported. It is unlikely that there will be a full removal of particles from the total environment, so some form of long term monitoring programme may be required plus a high standard of record keeping.