title: Action levels for automatic gamma-measurements based on probabilistic radionuclide transport calculations.
abstract: In the event of a nuclear or radiological emergency resulting in an atmospheric release of radioactive materials, stationary gamma-measurements, for example obtained from distributed, automatic monitoring stations, may provide a first assessment of exposures resulting from airborne and deposited activity. Decisions on the introduction of countermeasures for the protection of the public can be based on such off-site gamma measurements. A methodology is presented for calculation of gamma-radiation action levels for the introduction of specific countermeasures, based on probabilistic modelling of the dispersion of radionuclides and the radiation exposure. The methodology is applied to a nuclear accident situation with long-range atmospheric dispersion of radionuclides, and action levels of dose rate measured by a network of monitoring stations are estimated for sheltering and foodstuff restrictions. It is concluded that the methodology is applicable to all emergency countermeasures following a nuclear accident but measurable quantities other than ambient dose equivalent rate are needed for decisions on the introduction of foodstuff countermeasures.
authors.affiliation: Risø National Laboratory, DK-4000 Roskilde, Denmark. bent.lauritzen@risoe.dk
authors.forename: Bent
authors.initials: B
authors.lastname: Lauritzen
authors.forename: Per
authors.initials: P
authors.lastname: Hedemann-Jensen
mesh_terms: D004189:Disaster Planning / Q000379:methods*; D005720:Gamma Rays; D006801:Humans; D008962:Models, Theoretical; D011834:Radiation Monitoring / Q000379:methods; D011835:Radiation Protection / Q000379:methods*; D018788:Radioactive Hazard Release; D011868:Radioisotopes; D018570:Risk Assessment
chemical_list: D011868:Radioisotopes