EN ISO 18256-2:2021

SLOVENSKI STANDARD
01-april-2021
Tehnologija jedrskih goriv - Raztapljanje materialov, ki vsebujejo plutonijev dioksid
- 2. del: Raztapljanje peletov in praškov MOX (ISO 18256-2:2019)
Nuclear fuel technology - Dissolution of plutonium dioxide-containing materials - Part 2:
Dissolution of MOX pellets and powders (ISO 18256-2:2019)
Technologie du combustible nucléaire - Dissolution des matériaux contenant du dioxyde
de plutonium - Partie 2: Dissolution de pastilles et poudres de MOX (ou mélanges
d'oxydes) (ISO 18256-2:2019)
Ta slovenski standard je istoveten z: EN ISO 18256-2:2021
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 18256-2
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2021
EUROPÄISCHE NORM
ICS 27.120.30
English Version
Nuclear fuel technology - Dissolution of plutonium
dioxide-containing materials - Part 2: Dissolution of MOX
pellets and powders (ISO 18256-2:2019)
Technologie du combustible nucléaire - Dissolution des
matériaux contenant du dioxyde de plutonium - Partie
2: Dissolution de pastilles et poudres de MOX (ou
mélanges d'oxydes) (ISO 18256-2:2019)
This European Standard was approved by CEN on 18 January 2021.

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, Turkey 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
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 18256-2:2021 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO 18256-2:2019 has been prepared by Technical Committee ISO/TC 85 "Nuclear energy,
nuclear technologies, and radiological protection” of the International Organization for Standardization
(ISO) and has been taken over as EN ISO 18256-2:2021 by 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 August 2021, and conflicting national standards shall
be withdrawn at the latest by August 2021.
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.
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, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 18256-2:2019 has been approved by CEN as EN ISO 18256-2:2021 without any
modification.
INTERNATIONAL ISO
STANDARD 18256-2
First edition
2019-01
Nuclear fuel technology — Dissolution
of plutonium dioxide-containing
materials —
Part 2:
Dissolution of MOX pellets and
powders
Technologie du combustible nucléaire — Dissolution des matériaux
contenant du dioxyde de plutonium —
Partie 2: Dissolution de pastilles et poudres de MOX (ou mélanges
d'oxydes)
Reference number
ISO 18256-2:2019(E)
©
ISO 2019
ISO 18256-2:2019(E)
© ISO 2019
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
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Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

ISO 18256-2:2019(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Summary of the method . 1
5 Apparatus and reagents . 2
5.1 Apparatus . 2
5.2 Reagents. 2
6 Sample dissolution . 3
6.1 Procedure for common plutonium containing materials . 3
6.2 Solution adjustment (optional) . 5
7 Quality control . 6
Bibliography . 7
ISO 18256-2:2019(E)
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
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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 documents 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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
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expressions related to conformity assessment, as well as information about ISO's adherence to the
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.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.
A list of all the parts in the ISO 18256 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 © ISO 2019 – All rights reserved

ISO 18256-2:2019(E)
Introduction
This document describes a method to dissolve samples consisting of MOX pellets or powders to provide
suitable aliquots for subsequent analysis of elemental concentration and isotopic composition.
INTERNATIONAL STANDARD ISO 18256-2:2019(E)
Nuclear fuel technology — Dissolution of plutonium
dioxide-containing materials —
Part 2:
Dissolution of MOX pellets and powders
1 Scope
This document specifies the dissolution of samples consisting of MOX pellets or powders to provide
suitable aliquots for subsequent analysis of elemental concentration and isotopic composition.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
4 Summary of the method
Among the factors affecting the formation of solid solution and hence, the ease of dissolution are:
— the method of fuel fabrication (i.e. mechanically blended oxides, co-precipitated oxides, microwave
denitrated oxides or sol-gel oxides);
— the degree of sintering.
Therefore, different dissolution methods are applied depending on the type of MOX sample to be
dissolved.
The radiological hazard of plutonium and the need to minimize the waste shall be taken into account
when choosing the mass of the sample to be dissolved. A MOX mass of 0,1 g to 10 g should be sufficient
for most of the analyses. Some analysis may however require more material.
For the highest possible assay accuracy only gravimetric dissolution methods are recommended.
However for a less critical assay, volumetric dissolution may be appropriate.
ISO 18256-2:2019(E)
For grain-size powders, the sample is transferred in a pre-weighed flask or vial made of glass, high-
1)
TM
density polyethylene (HDPE), polytetrafluoroethylene (PTFE), Nalgene or other container types,
but the choice of the container has consequences.
— When using a glass dissolution vessel, the added fluoride will attack the glass (resulting in a
falsification of the pre-weighed tare) but with the benefit that the fluoride is ultimately removed
from the solution via release of volatile SiF . The resulting reduction in fluoride content of the final
solution guards against the formation of insoluble plutonium fluoride (especially below 8 M), which
would negatively bias the plutonium element content up to 0,1 % [or more when large quantities of
hydrofluoric acid
...