Effect of oxygen on gas emitted from polymer irradiated using Swift Heavy Ion beams

Abstract : At the end of their life, polymers used in the nuclear industry are placed in Intermediate Level – Long Lived Waste packages. For safety purposes, the amount of gas emitted by these organic materials has to be estimated. γ ir-radiations are commonly used to simulate β and γ-emitters; α-emitters simulation are more problematic because of experimental difficulties. It is proposed in France to use particle accelerators with ions providing stopping power values in polymers equivalent to the one of α-emitters. This approach has been validated under inert atmosphere; the question now arises of the effect of the presence of oxygen. We showed that the hydrogen release is slightly affected by atmosphere of irradiation and increases with LET. The evolution with LET of CO2 release is dependent on the polymer: it increases for polymers with low G(CO2) at low LET and decreases for polymers presenting relatively high G(CO2) at low LET.