EN ISO 22765:2025

SLOVENSKI STANDARD
01-marec-2025
Tehnologija jedrskih goriv - Sintrani peleti (U, Pu)O2 - Navodilo za pripravo
keramografske preiskave mikrostrukture (ISO 22765:2025)
Nuclear fuel technology - Sintered (U,Pu)O2 pellets - Guidance for ceramographic
preparation for microstructure examination (ISO 22765:2025)
Kernbrennstofftechnologie - Gesinterte (U,Pu)O¿-Pellets - Leitfaden für die
keramographische Herstellung der Proben zur Untersuchung des Feingefüges (ISO
22765:2025)
Technologie du combustible nucléaire - Pastilles (U,Pu)O2 frittées - Préconisations
relatives à la préparation céramographique pour examen de la microstructure (ISO
22765:2025)
Ta slovenski standard je istoveten z: EN ISO 22765:2025
ICS:
27.120.30 Cepljivi materiali in jedrska Fissile materials and nuclear
gorivna tehnologija fuel technology
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 22765
EUROPEAN STANDARD
NORME EUROPÉENNE
January 2025
EUROPÄISCHE NORM
ICS 27.120.30 Supersedes EN ISO 22765:2019
English Version
Nuclear fuel technology - Sintered (U,Pu)O2 pellets -
Guidance for ceramographic preparation for
microstructure examination (ISO 22765:2025)
Technologie du combustible nucléaire - Pastilles Kernbrennstofftechnologie - Gesinterte (U,Pu)O2-
(U,Pu)O2 frittées - Recommandations relatives à la Pellets - Leitfaden für die keramographische
préparation céramographique pour examen de la Herstellung der Proben zur Untersuchung des
microstructure (ISO 22765:2025) Feingefüges (ISO 22765:2025)
This European Standard was approved by CEN on 10 January 2025.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 22765:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 22765:2025) has been prepared by Technical Committee ISO/TC 85 "Nuclear
energy, nuclear technologies, and radiological protection" in collaboration with Technical Committee
CEN/TC 430 “Nuclear energy, nuclear technologies, and radiological protection” the secretariat of
which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by July 2025, and conflicting national standards shall be
withdrawn at the latest by July 2025.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 22765:2019.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 22765:2025 has been approved by CEN as EN ISO 22765:2025 without any modification.

International
Standard
ISO 22765
Second edition
Nuclear fuel technology — Sintered
2025-01
(U,Pu)O pellets — Guidance for
ceramographic preparation for
microstructure examination
Technologie du combustible nucléaire — Pastilles (U,Pu)
O frittées — Recommandations relatives à la préparation
céramographique pour examen de la microstructure
Reference number
ISO 22765:2025(en) © ISO 2025
ISO 22765:2025(en)
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 22765:2025(en)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 2
6 Reagents and resin . 3
7 Operating procedure . 3
7.1 Specimen cutting .3
7.2 Resin embedding .3
7.3 Rough polishing .3
7.4 Fine polishing .4
8 Structure development . 4
8.1 General .4
8.2 Development by thermal treatment .4
8.3 Development by chemical etching .5
8.4 Development by ion etching . . .5
Bibliography . 7

iii
ISO 22765:2025(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
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, in collaboration
with the European Committee for Standardization (CEN) Technical Committee CEN/TC 430, Nuclear energy,
nuclear technologies, and radiological protection, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
This second edition cancels and replaces the first edition (ISO 22765:2016), which has been technically
revised.
The main changes are as follows:
— in Clause 1, additional comments about equipment and preparation;
— in Clause 4, addition of required steps according to analyses to be carried out;
— in Clauses 7 and 8, update of the parameters used for polishing.
A list of all parts in the ISO 22765 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 22765:2025(en)
Nuclear fuel technology — Sintered (U,Pu)O pellets —
Guidance for ceramographic preparation for microstructure
examination
1 Scope
This document is applied to fuel fabrication. It describes the ceramographic procedure used to prepare
sintered (U,Pu)O pellets for qualitative and quantitative examination of the (U,Pu)O pellet microstructure.
2 2
The examinations are performed
a) before any treatment or any etching, and
b) after thermal treatment or after chemical or ion etching.
They allow
— observation of any cracks, intra- and intergranular pores or inclusions, and
— measurement of the grain size, porosity and plutonium homogeneity distribution.
The mean grain diamete
...