| Abstrakt: |
Two types of plants (lettuce and radish) were contaminated by dry deposition of radioactive aerosols (137Cs, 85Sr, 133Ba and 123mTe). Due to the rain efficiency in decreasing radiological contamination of crops, a rain scenario was applied on the two types of plants. These experiments aimed at improving the prediction of the consequences on agricultural products of a nuclear accident occurring on a PWR, and at improving the understanding of the different processes occurring between contamination and harvest. For a plant species at a given stage of its growth cycle, the interception of the four radionuclides was found to be identical and varied from 68% for radish to 75% (at the middle of ripeness stage) or 78% (at the mature plant stage). Using a conceptual model, the predominance between the two processes - washing-off the leaves and absorption through the leaves cuticles allowing translocation - was evidenced. For Cs, Sr and Ba, for both the lettuce and the radish, washing-off on the foliar cover was the most significant during the first rain. The absorption process inside the plant became dominant only from the third rain event. Tellurium had a particular behaviour: it was non-mobile and stayed put on the leaves. The values of the washing-off and absorption coefficients were estimated. The global transfer factor values were dependant on both the radionuclides and the plant species; nevertheless, a higher value was obtained for cesium, regardless of the plant and the rainfall (from 0.06 m2.kg$_{\scriptsize\textrm{fresh}}$-1 for radish to 0.1 m2.kg$_{\scriptsize\textrm{fresh}}$-1for a whole lettuce). |
