Postactivation annealing fission product release

Postactivation annealing fission product release data can be analyzed on the basis of a model that assumes the release to be a diffusion-con-trolled process from a spherical particle. The release is limited by diffusion either in the kernel or in the coating. This model is discussed by Norman and Winchell (9) in another chapter in this volume. 

Postactivation annealing fission product release measurements have shown that the excellent retention of iodine and noble fission gases by pyrolytic carbon-coated fuel particles is unaffected by irradiation up to 24% FIMA. These data are interpreted as indicating that the pyrolytic carbon coatings remain undamaged by these high levels of irradiation. 

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