TO DEVELOP MORE COMPREHENSIVE MODEL OF ATMOSPHERIC TRANSFER AND DEPOSITION ON A LONG DISTANCE RANGE, TAKING INTO ACCOUNT THE INFLUENCE OF LOCAL PRECIPITATIONS AND THE IMPACT OF COMPLEX TOPOLOGY.
Past experiences have shown that it is difficult to specify closely the source term either during or immediately after an accidental release of radioactive material.
Here, the source term comprises:
the chemical nature of the radonuclides released;
the amount and time distribution for each radionuclide released;
the physical state of the various radionuclides released (whether gaseous, aerosol or organic or inorganic vapour).
The purpose of this study, however, is to put forward a method for using the results of air concentration and deposition measurements made in a given zone to obtain the best estimate of the source term, and of the overall air concentration and deposit fields, while at the same time optimising the parameters required in the atmospheric transport model.