Nuclear Energy - Fuel technology - Determination of the O/M ratio in MOX pellets by the gravimetric method (ISO 21484:2017)

ISO 21484:2017 describes a method for determining the Oxygen-to-Metal (O/M) ratio in mixed uranium-plutonium oxide (U,Pu)O2 ± X pellets. The parameters given in the following paragraphs are relevant for pellets within a range of O/M ratio corresponding to 1,98 to 2,01. The method described in the document is adapted, with regard to the parameters, if the expected values of O/M ratio are outside the range.

Kernenergie - Brennstofftechnologie - Bestimmung des O/M-Verhältnisses in MOX-Pellets mit dem gravimetrischen Verfahren (ISO 21484:2017)

Dieses Dokument beschreibt ein Verfahren zur Bestimmung des Verhältnisses von Sauerstoff zu Metall (O/M) (en: Oxygen-to-Metal) in Pellets aus Uran-Plutonium-Mischoxiden (U,Pu)O2 ± X. Die in den folgenden Abschnitten angegebenen Parameter sind für Pellets mit einem O/M Verhältnis in einem Bereich von 1,98 bis 2,01 relevant. Das in diesem Dokument beschriebene Verfahren wird hinsichtlich der Parameter angepasst, wenn die erwarteten Werte des O/M Verhältnisses außerhalb dieses Bereichs liegen.

Énergie nucléaire - Technologie du combustible - Détermination du rapport O/M dans les pastilles MOX par la méthode gravimétrique (ISO 21484:2017)

L'ISO 21484:2017 décrit une méthode de détermination du rapport oxygène/métal (O/M) dans les pastilles de mélange d'oxydes d'uranium et de plutonium (U,Pu)O2 ± X. Les paramètres indiqués dans les paragraphes suivants sont applicables aux pastilles dont le rapport O/M est compris entre 1,98 et 2,01. La méthode décrite dans le présent document doit être adaptée, en ce qui concerne les paramètres, si les valeurs attendues du rapport O/M ne sont pas situées dans cette plage.

Jedrska energija - Tehnologija goriv - Ugotavljanje razmerja O/M v peletih MOX z gravimetrično metodo (ISO 21484:2017)

Metoda za ugotavljanje razmerja med kisikom in kovino O/M v peletih z mešanico uranovega in plutonijevega oksida (MOX) (U,Pu)O2 ± X. Parametri, ki so podani v spodnjih odstavkih, se navezujejo na pelete znotraj območja razmerja O/M 1,98 : 2,01. Metoda, ki je opisana v dokumentu, je prikrojena v skladu s parametri, če so pričakovane vrednosti razmerja O/M zunaj tega območja.

General Information

Status
Published
Publication Date
11-Jun-2019
Withdrawal Date
30-Dec-2019
ICS
17.240 - Radiation measurements
 
27.120.30 - Fissile materials and nuclear fuel technology
Technical Committee
CEN/TC 430 - Nuclear energy, nuclear technologies, and radiological protection
Drafting Committee
CEN/TC 430 - Nuclear energy, nuclear technologies, and radiological protection
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Start Date
12-Jun-2019
Due Date
28-Nov-2020
Completion Date
12-Jun-2019
Ref Project
SIST EN ISO 21484:2019 - Nuclear Energy - Fuel technology - Determination of the O/M ratio in MOX pellets by the gravimetric method (ISO 21484:2017)

Overview

EN ISO 21484:2019 - "Nuclear energy - Fuel technology - Determination of the O/M ratio in MOX pellets by the gravimetric method" (ISO 21484:2017) specifies a laboratory gravimetric procedure to determine the oxygen-to-metal (O/M) ratio in mixed uranium‑plutonium oxide (MOX) (U,Pu)O2±x pellets. The published parameters apply primarily to pellets with O/M values in the range 1.98 to 2.01. The method uses controlled oxidation–reduction heat treatment and mass measurement to establish the stoichiometric deviation X by converting the sample to an O/M of exactly 2.000.

Key topics and technical requirements

  • Principle: Adjust sample O/M to 2.000 by controlled oxidation–reduction and calculate initial O/M from the mass change.
  • Scope limits: Parameter recommendations target O/M 1.98–2.01; parameters are adaptable for values outside this range.
  • Reagents and gases:
    • Nitric acid (50 % v/v) for crucible cleaning.
    • Purge gases: high‑purity air, inert gas (argon or nitrogen) or hydrogen/mixtures; purity recommendations and limits for O2/H2O/N2 impurities are specified.
  • Apparatus and consumables:
    • Furnace capable up to ~950 °C (muffle or equivalent, e.g., IR lamp heating) with gas sweeping control.
    • Platinum or quartz crucibles.
    • Analytical balance with at least ±0.1 mg accuracy for typical samples (±0.01 mg for very small samples).
  • Sampling & sample preparation: Representative sampling from pellet batches; precautions to avoid oxidation during handling (e.g., argon atmosphere, argon‑filled containers).
  • Procedure highlights:
    • Crucible cleaning and pre‑weighing.
    • Weigh sample + crucible, perform heat‑treatment cycles (example cycles provided: argon → air → argon → argon+H2 at ~900 °C with specified hold times).
    • Final weighing and calculation of mean atomic mass and O/M ratio.
  • Quality characteristics: The standard includes sections on calculation, precision, accuracy, sensitivity and required content for the test report.

Applications and users

  • Quality control and acceptance testing in MOX fuel fabrication.
  • Analytical and research laboratories in nuclear fuel technology, including fuel manufactories and regulatory/inspection bodies.
  • R&D groups assessing stoichiometry, fuel performance, and process control for mixed‑oxide pellets.
  • Useful for safety and compliance checks where precise oxygen content affects thermal, mechanical and irradiation behavior of MOX fuels.

Related standards

  • EN ISO 21484:2019 is the CEN adoption of ISO 21484:2017; it was prepared under ISO/TC 85 (Nuclear energy). Users often apply this method alongside standards for MOX fabrication, fuel characterization and radiochemical analysis (consult national and CEN references for complementary standards).

Keywords: EN ISO 21484:2019, O/M ratio, MOX pellets, gravimetric method, (U,Pu)O2, oxygen‑to‑metal ratio, nuclear fuel analysis, muffle furnace, analytical balance.

Frequently Asked Questions

EN ISO 21484:2019 is a standard published by the European Committee for Standardization (CEN). Its full title is "Nuclear Energy - Fuel technology - Determination of the O/M ratio in MOX pellets by the gravimetric method (ISO 21484:2017)". This standard covers: ISO 21484:2017 describes a method for determining the Oxygen-to-Metal (O/M) ratio in mixed uranium-plutonium oxide (U,Pu)O2 ± X pellets. The parameters given in the following paragraphs are relevant for pellets within a range of O/M ratio corresponding to 1,98 to 2,01. The method described in the document is adapted, with regard to the parameters, if the expected values of O/M ratio are outside the range.

ISO 21484:2017 describes a method for determining the Oxygen-to-Metal (O/M) ratio in mixed uranium-plutonium oxide (U,Pu)O2 ± X pellets. The parameters given in the following paragraphs are relevant for pellets within a range of O/M ratio corresponding to 1,98 to 2,01. The method described in the document is adapted, with regard to the parameters, if the expected values of O/M ratio are outside the range.

EN ISO 21484:2019 is classified under the following ICS (International Classification for Standards) categories: 17.240 - Radiation measurements; 27.120.30 - Fissile materials and nuclear fuel technology. The ICS classification helps identify the subject area and facilitates finding related standards.

You can purchase EN ISO 21484:2019 directly from iTeh Standards. The document is available in PDF format and is delivered instantly after payment. Add the standard to your cart and complete the secure checkout process. iTeh Standards is an authorized distributor of CEN standards.

Standards Content (Sample)


SLOVENSKI STANDARD
01-september-2019
Jedrska energija - Tehnologija goriv - Ugotavljanje razmerja O/M v peletih MOX z
gravimetrično metodo (ISO 21484:2017)
Nuclear Energy - Fuel technology - Determination of the O/M ratio in MOX pellets by the
gravimetric method (ISO 21484:2017)
Kernenergie - Brennstofftechnologie - Bestimmung des O/M-Verhältnisses in MOX-
Pellets mit dem gravimetrischen Verfahren (ISO 21484:2017)
Énergie nucléaire - Technologie du combustible - Détermination du rapport O/M dans les
pastilles MOX par la méthode gravimétrique (ISO 21484:2017)
Ta slovenski standard je istoveten z: EN ISO 21484:2019
ICS:
17.240 Merjenje sevanja Radiation measurements
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 21484
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2019
EUROPÄISCHE NORM
ICS 17.240; 27.120.30
English Version
Nuclear Energy - Fuel technology - Determination of the
O/M ratio in MOX pellets by the gravimetric method (ISO
21484:2017)
Énergie nucléaire - Technologie du combustible - Kernenergie - Brennstofftechnologie - Bestimmung des
Détermination du rapport O/M dans les pastilles MOX O/M-Verhältnisses in MOX-Pellets mit dem
par la méthode gravimétrique (ISO 21484:2017) gravimetrischen Verfahren (ISO 21484:2017)
This European Standard was approved by CEN on 8 March 2019.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, 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
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21484:2019 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO 21484:2017 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 21484:2019 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 December 2019, and conflicting national standards
shall be withdrawn at the latest by December 2019.
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, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 21484:2017 has been approved by CEN as EN ISO 21484:2019 without any modification.

INTERNATIONAL ISO
STANDARD 21484
Second edition
2017-01
Nuclear Energy — Fuel technology —
Determination of the O/M ratio in MOX
pellets by the gravimetric method
Énergie nucléaire — Technologie du combustible — Détermination
du rapport O/M dans les pastilles MOX par la méthode gravimétrique
Reference number
ISO 21484:2017(E)
©
ISO 2017
ISO 21484:2017(E)
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, 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.
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Tel. +41 22 749 01 11
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copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved

ISO 21484:2017(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reactions . 1
6 Reagents and materials . 1
7 Apparatus . 2
8 Sampling . 2
9 Procedure. 2
9.1 Preliminary test . 2
9.2 Preparing the crucibles . . 2
9.3 Weighing the sample . 2
9.4 Heat treatment cycles . 3
9.4.1 General. 3
9.4.2 Example 1 . 3
9.4.3 Example 2 . 3
9.5 Final weighing . 3
10 Calculation . 4
10.1 Mean atomic mass of oxide after heat treatment . 4
10.2 Calculation of O/M ratio. 4
11 Precision . 4
11.1 Accuracy . 4
11.2 Precision . 5
11.3 Sensitivity .
...

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