The Weerie program for assessing the radiological consequences of airborne effluents from nuclear installations

Abstract

A mathematical model has been devised for guidance in the safety and siting aspects of nuclear installations under operational or accident conditions. The model begins with the full fission product inventory applicable to the fuel at the time of interest generated for any reactor type and irradiation history. The amount of fuel involved in the incident may vary as a function of time and either a time decaying or constant fission product inventory may be used to specify the release. The activity leaks from the circuit with allowances for time-dependent plateout, resuspension and filtration of each elemental species. By preserving the full nuclide decay schemes, nuclides leaking into the atmosphere depend not only upon their own release behaviour but also on that of their precursors. The effluent in the atmosphere is dispersed from an effective stack height and allowance is made for building entrainment. Standard meteorological dispersion models are used and the effects of radioactive buildup and decay, ground and inversion reflections and ground deposition are taken into account. WEERIE then evaluates the inhalation and the cloud β doses, while integration over the volume of the plume leads to estimates of the cloud γ exposure. WEERIE is written in FORTRAN IV (H) and executes on the IBM 370/165 computer requiring 250 kbytes of fast core storage. Execution times vary with the degree of precision requested in the cloud-γ routine, but typically doses and exposures may be evaluated at the rate of 200 observation points per minute. © 1973 Health Physics Society.