ISO 16795:2024

International
Standard
ISO 16795
Second edition
Nuclear energy — Determination
2024-04
of Gd O content in pellets
2 3
containing uranium oxide by X-ray
fluorescence spectrometry
Énergie nucléaire — Détermination de la teneur de Gd O par
2 3
spectrométrie à fluorescence X dans des pastilles combustibles
contenant de l'oxyde d'uranium
Reference number
© ISO 2024
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ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 1
6 Reagents . 2
7 Preparation of standards . 2
8 Polishing . 3
9 Equipment calibration . 3
9.1 Angle calibration.3
9.2 Pulse-height distribution .3
9.3 Background correction .3
9.4 Stability (sensitivity) check .3
10 Calibration curve . 4
11 Measurements . 4
12 Precision and accuracy . 4
13 Test report . 4
Annex A (informative) Angle calibration and background correction. 6
Annex B (informative) Precision and accuracy . 7
Bibliography . 8

iii
Foreword
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The procedures used to develop this document and those intended for its further maintenance are described
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This document was prepared by Technical Committee ISO/TC 85, Nuclear energy, nuclear technologies, and
radiological protection, Subcommittee SC 5, Nuclear installations, processes and technologies
This second edition cancels and replaces the first edition (ISO 16795:2004), which has been technically
revised.
The main changes are as follows:
— the title of this document has been modified;
— requirements for the standard pellet has been added in Clause 7;
— range of Gd O content covered by calibration curve has been added in Clause 10;
2 3
A list of all parts in the ISO 16795 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
International Standard ISO 16795:2024(en)
Nuclear energy — Determination of Gd O content in pellets
2 3
containing uranium oxide by X-ray fluorescence spectrometry
1 Scope
This document specifies a method which covers the determination of Gd O content in UO fuel pellets, by
2 3 2
X-ray fluorescence spectrometry.
Either wave dispersion X-ray fluorescence (WD-XRF) or energy dispersion X-ray fluorescence (ED-XRF) is
applicable, however, this document states a method by using WD-XRF using Gd Lα-line.
This method has been tested for mass fractions of from 2 % to 10 % Gd O .
2 3
2 Normative references
ISO 17034, General requirements for the competence of reference material producers
ASTM C1128, Standard Guide for Preparation of Working Reference Materials for Use in Analysis of Nuclear Fuel
Cycle Materials
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at th
...