Mesoscale dispersion of ⁸⁵Kr in the vicinity of the AREVA La Hague reprocessing plant

¹ IRSN/DEI/SECRE, Laboratoire de Radioécologie, Cherbourg-Octeville, France
² RPII, Radiological Protection Institute of Ireland, Clonskeagh, Dublin 14, Ireland

e-mail: olivier.connan@irsn.fr

Abstract

The Institut de Radioprotection et de Sureté Nucléaire (IRSN) performed a series of air sampling campaigns at mesoscale distances (10–80 km) from the AREVA La Hague reprocessing plant (north west of France) between 2007 and 2009. These samples were collected in order to test and optimise a technique to measure low krypton-85 (⁸⁵Kr) air concentrations, and to investigate the performance of three atmospheric dispersion models (RIMPUFF, HySplit, and ADMS). This paper presents ⁸⁵Kr air concentrations measured at both land and sea locations. In addition, this paper compares the measured ⁸⁵Kr air concentrations, which varied from 2 to 8000 Bq m⁻³, with the predictions from the atmospheric dispersion models. During stable wind conditions, the dispersion models make reasonable estimates of the ⁸⁵Kr field measurements. In contrast, the models fail to accurately predict temporal peaks in concentration during periods of rapid and large changes in wind speed and/or wind direction.