Dispersion of positron emitting radioactive gases in a complex urban building array: a comparison of dose modelling approaches

摘要: A radiological assessment was carried out on the release of positron-emitting radioactive gases from a roof-level stack at central London site. Different modelling approaches were performed to investigate range radiation doses representative persons. Contributions plume inhalation, gamma shine and immersion effective dose taken into account. Dry wet surface deposition roof, exposure contamination skin roof-workers, added only mean 4.7% neglected. 1:200 scale model, consisting surrounding buildings, tested in wind tunnel simulate pollutant dispersion near-field region i.e. rooftop. Concentration field measurements converted dose, including for roof-workers installing glass cladding building. Changes building shape, addition layer, investigated terms flow pattern significant differences found between two cases. Pollutant concentrations also modelled using Air Dispersion Modelling System (ADMS) results used calculate same meteorological data set source terms. Sector averaged estimates greater than ADMS figure by approximately factor three. heights simulations order determine best height replacement flue Other techniques investigated: wake models, modified Gaussian methods uniform dilution hemispherical volume show wide variation predicted possible with different approaches. Large simpler analytic indicated that more robust assessments, based complex approaches, required achieve satisfactory groups adjacent buildings