Title: Comparison between field measurements of 85Kr around the BNFL Sellafield reprocessing plant and the predictions of the NRPB R-91 and UK-ADMS atmospheric dispersion models

Authors: R. Hill, I. Lowles, I. Teasdale, N. Chambers, C. Puxley, T. Parker

Addresses: Westlakes Research Institute, The Princess Royal Building, Westlakes Science and Technology Park, Moor Row, Cumbria, CA24 3LN, UK. Westlakes Research Institute, The Princess Royal Building, Westlakes Science and Technology Park, Moor Row, Cumbria, CA24 3LN, UK. Westlakes Research Institute, The Princess Royal Building, Westlakes Science and Technology Park, Moor Row, Cumbria, CA24 3LN, UK. Westlakes Research Institute, The Princess Royal Building, Westlakes Science and Technology Park, Moor Row, Cumbria, CA24 3LN, UK. Westlakes Research Institute, The Princess Royal Building, Westlakes Science and Technology Park, Moor Row, Cumbria, CA24 3LN, UK. British Nuclear Fuels Limited, Sellafield Works, Seascale, Cumbria, CA20 1PG, UK

Abstract: Air concentrations of the radioisotope krypton-85 (85Kr), released from the BNFL Sellafield reprocessing site, were compared with the predictions of two atmospheric dispersion models NRPB R-91 and the next generation UK-ADMS model (version 3). Data on stack emissions and local meteorology were used as model input, whilst building effects were included using a simple ||effective stack height|| approach. Both models tended to make conservative estimates of air concentrations, with slightly higher overestimations being predicted by the UK-ADMS model. Both models had similar fractions of predictions within a factor of two (35% for UK-ADMS and 34% for R-91) and five (56% for UK-ADMS and 62% for R-91) of the measurements. It was concluded that, when using the simple ||effective stack height|| approach, there was little discernible advantage of applying the UKADMS model in preference to the R-91 model at the BNFL Sellafield site. Further research will investigate the influence of the UK-ADMS ||complex effects|| modules on the dispersion predictions.

Keywords: complex site; Gaussian plume modelling; krypton-85; model validation; nuclear fuel reprocessing; radioactivity.

DOI: 10.1504/IJEP.2001.000627

International Journal of Environment and Pollution, 2001 Vol.16 No.1/2/3/4/5/6, pp.315-327

Published online: 07 Jul 2003 *

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