ČSN EN ISO 16424 (404053)

Annotation of standard text ČSN EN ISO 16424 (404053):

This International Standard is applicable to the evaluation of the homogeneity of Gd distribution within gadolinium fuel blends, and the determination of the Gd2O3 content in sintered fuel pellets of Gd2O3+UO2 from 1 % to 10 %, by measurements of gadolinium (Gd) and uranium (U) elements using ICP-AES. After performing measurements of Gd and U elements using ICP-AES, if statistical methodology is additionally applied, homogeneity of Gd distribution within a Gd fuel pellet lot can also be evaluated. However, this International Standard covers the statistical methodology only on a limited basis. NOTE 1 - ISO 16796 also provides a method for Gd2O3 content determination by atomic emission spectrometry using an inductively coupled plasma source (ICP-AES). The methodology of ISO 16796 is different from the one of this International Standard. NOTE 2 - In this International Standard, gadolinium fuel blend represents a mixture of uranium dioxide (UO2) powder and gadolinium oxide (Gd2O3) powder. The physically blended and homogenized powder may additionally contain in it rather large quantities of uranium oxide (U3O8) powder particles and/or the M3O8 powder particles obtained by oxidation of Gd pellets. In this International Standard, the symbol "M" in the chemical formula "M3O8" and in the terminology "O/M ratio" represents metallic elements U and Gd