prEN ISO 12800

Nuclear fuel technology - Guidelines on the measurement of the specific surface area of uranium dioxide and plutonium dioxide powders by the BET method (ISO/DIS 12800:2026)

ISO 12800:2017 gives guidelines on the determination of the specific surface area of as-fabricated uranium dioxide powder by volumetric or gravimetric determination of the amount of nitrogen adsorbed on the powder, and can be applied to other similar materials, e.g. U3O8, UO2-PuO2 powders, and other bodies with similar surface areas, e.g. powder granules or green pellets, provided that the conditions described are fulfilled. Modifications using other adsorbing gases are included.
The method is relevant as long as the expected value is in the range between 1 m2/g and 10 m2/g.

Kernbrennstofftechnologie - Leitlinien für die Messung der spezifischen Oberfläche von Uranoxid-Pulvern mittels des BET-Verfahrens (ISO/DIS 12800:2026)

Technologie du combustible nucléaire - Lignes directrices pour le mesurage de l'aire massique (surface spécifique) des poudres d'oxyde d'uranium et de plutonium par la méthode BET (ISO/DIS 12800:2026)

L'ISO 12800:2017 est applicable à la détermination de l'aire massique de poudres brutes d'oxyde d'uranium par une mesure volumétrique ou gravimétrique de la quantité d'azote adsorbée sur la poudre. La méthode est applicable à d'autres matières comparables, par exemple aux poudres de U3O8 et aux mélanges UO2-PuO2, ainsi qu'à d'autres corps ayant des aires similaires, par exemple des granules de poudre ou des pastilles vertes, sous condition du respect des conditions définies. Des variantes utilisant d'autres gaz d'adsorption sont proposées.
La méthode reste pertinente tant que la valeur attendue est comprise entre 1 m2/g et 10 m2/g.

Tehnologija jedrskih goriv - Smernice za merjenje specifične površine prahu uranovega dioksida in plutonijevega dioksida po metodi BET (ISO/DIS 12800:2026)

General Information

• Status: Not Published
• Publication Date: 08-Aug-2027
• ICS: 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: 4060 - Closure of enquiry - Enquiry
• Start Date: 02-Apr-2026
• Completion Date: 02-Apr-2026
• Ref Project: oSIST prEN ISO 12800:2026 - Nuclear fuel technology - Guidelines on the measurement of the specific surface area of uranium dioxide and plutonium dioxide powders by the BET method (ISO/DIS 12800:2026)

Relations

• Revises: EN ISO 12800:2019 - Nuclear fuel technology - Guidelines on the measurement of the specific surface area of uranium oxide powders by the BET method (ISO 12800:2017)
• Effective Date: 22-Jan-2025

Overview

prEN ISO 12800:2026 (ISO/DIS 12800:2026) offers internationally recognized guidelines for measuring the specific surface area of uranium dioxide (UO₂) and plutonium dioxide (PuO₂) powders in nuclear fuel technology. Published by CEN and based on the ISO framework, this standard specifies the use of the Brunauer-Emmett-Teller (BET) method, employing volumetric or gravimetric determination of nitrogen adsorption. While primarily designed for as-fabricated uranium dioxide powder, it is also applicable to other uranium oxide forms, mixed oxide (MOX) powders, and additional materials with similar surface properties, provided the standard’s conditions are met. Modifications for other adsorbing gases are included to extend its applicability.

Key Topics

• BET Method Principles:

  • Utilizes the measurement of gas (standard is nitrogen) adsorbed on powder surfaces.
  • Both volumetric and gravimetric procedures are covered.
  • Focuses on materials where nitrogen does not chemically react or get absorbed by the sample.
  • Applicable when materials display adsorption isotherms suitable to BET analysis (typically type 2 and type 4 curves).

• Sample Preparation:

  • Ensures removal of surface contamination and impurities, especially moisture.
  • Specifies optimal pre-treatment routines for uranium and plutonium dioxide powders to prevent sintering or structural changes.
  • Defines suitable heating temperatures and durations for various powder types.

• Measurement Range:

  • Designed for samples where specific surface area values fall between 1 m²/g and 10 m²/g for uranium dioxide.
  • Applicable to plutonium dioxide in the 0.1 m²/g to 45 m²/g range.

• Procedural Flexibility:

  • Accommodates modifications with other adsorbing gases under specified conditions.
  • Allows for adaptation in sample mass and pre-measurement treatment according to material characteristics.

Applications

prEN ISO 12800 is essential in the quality management and characterization of nuclear fuel components, supporting:

• Nuclear Fuel Fabrication:

  • Assures consistent production quality by standardizing surface area measurements, which can influence fuel sintering, reactivity, and overall performance.
  • Facilitates process optimization in powder metallurgy and pressing operations for UO₂, PuO₂, and MOX fuel pellets.

• Material Research & Development:

  • Provides comparative data for the development of new nuclear fuel formulations or modifications.
  • Supports investigation and control of surface-driven properties in uranium and plutonium oxide powders.

• Regulatory Compliance & Safety:

  • Offers a traceable and standardized approach appreciated by industry regulators.
  • Ensures measurement methodologies meet international expectations for transparency and repeatability.

• Alternative Materials Testing:

  • Useful for analogous oxide materials or pelletized forms as long as BET method conditions are applicable.

Related Standards

For organizations working with uranium and plutonium oxide powders or other nuclear fuel materials, the following standards are closely connected to prEN ISO 12800:

• ISO 9277:2022
  Determination of the specific surface area of solids by gas adsorption - BET method. Provides foundational methodology referenced throughout prEN ISO 12800.
• Other Nuclear Fuel Technology Standards
  • Refer to ISO/TC 85/SC 5 technical documents for wider coverage of nuclear fuel fabrication, handling, and characterization.
  • ICS 27.120.30 series for standards dealing specifically with fissile materials and nuclear fuel processing.

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By following the guidelines in prEN ISO 12800:2026, laboratories and fuel manufacturers can achieve precise and comparable results in measuring the specific surface area of uranium dioxide and plutonium dioxide powders, reinforcing quality, safety, and innovation in the nuclear fuel sector.

Standards Content (Sample)

SLOVENSKI STANDARD
01-marec-2026
Tehnologija jedrskih goriv - Smernice za merjenje specifične površine prahu
uranovega dioksida in plutonijevega dioksida po metodi BET (ISO/DIS 12800:2026)
Nuclear fuel technology - Guidelines on the measurement of the specific surface area of
uranium dioxide and plutonium dioxide powders by the BET method (ISO/DIS
12800:2026)
Kernbrennstofftechnologie - Leitlinien für die Messung der spezifischen Oberfläche von
Uranoxid-Pulvern mittels des BET-Verfahrens (ISO/DIS 12800:2026)
Technologie du combustible nucléaire - Lignes directrices pour le mesurage de l'aire
massique (surface spécifique) des poudres d'oxyde d'uranium et de plutonium par la
méthode BET (ISO/DIS 12800:2026)
Ta slovenski standard je istoveten z: prEN ISO 12800
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.

DRAFT
International
Standard
ISO/DIS 12800
ISO/TC 85/SC 5
Nuclear fuel technology —
Secretariat: BSI
Guidelines on the measurement of
Voting begins on:
the specific surface area of uranium
2026-01-08
dioxide and plutonium dioxide
Voting terminates on:
powders by the BET method
2026-04-02
ICS: 27.120.30
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Reference number
ISO/DIS 12800:2026(en)
DRAFT
ISO/DIS 12800:2026(en)
International
Standard
ISO/DIS 12800
ISO/TC 85/SC 5
Nuclear fuel technology —
Secretariat: BSI
Guidelines on the measurement of
Voting begins on:
the specific surface area of uranium
dioxide and plutonium dioxide
Voting terminates on:
powders by the BET method
ICS: 27.120.30
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2026
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
BE CONSIDERED IN THE LIGHT OF THEIR
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
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WHICH REFERENCE MAY BE MADE IN
or ISO’s member body in the country of the requester.
NATIONAL REGULATIONS.
ISO copyright office
RECIPIENTS OF THIS DRAFT ARE INVITED
CP 401 • Ch. de Blandonnet 8
TO SUBMIT, WITH THEIR COMMENTS,
CH-1214 Vernier, Geneva
NOTIFICATION OF ANY RELEVANT PATENT
Phone: [phone]
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ISO/DIS 12800:2026(en)
ii
ISO/DIS 12800:2026(en)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
4.1 Summary of the BET method .1
4.2 Isothermal adsorption curves .2
4.3 Conditions and assumptions .3
5 Procedure . 3
5.1 Sample preparation .3
5.1.1 Uranium dioxide powders .3
5.1.2 Plutonium dioxide powders .3
5.1.3 Mass of sample .3
5.2 Volumetric measurement .4
5.3 Gravimetric measurement .4
5.4 Multipoint and single-point methods .4
5.5 Dynamic method (carrier gas method) .4
5.6 Alternative methods .4
6 Expression of results . 5
6.1 Methods of calculation .5
6.1.1 Multipoint determination .5
6.1.2 Single-point determination .7
6.2 Precision and accuracy .7
7 Test report . 7
Bibliography . 8

iii
ISO/DIS 12800:2026(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
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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
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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.
This second edition cancels and replaces the first edition (ISO 12800:2003), which has been technically
revised.
iv
DRAFT International Standard ISO/DIS 12800:2026(en)
Nuclear fuel technology — Guidelines on the measurement of
the specific surface area of uranium dioxide and plutonium
dioxide powders by the BET method
1 Scope
This document is applicable to fuel fabrication. It gives guidelines on the determination of the specific
surface area of as-fabricated uranium dioxide and plutonium dioxide powders by volumetric or gravimetric
determination of the amount of nitrogen adsorbed on the powder. The measurement of other uranium oxide
powders refers to uranium dioxide, such as UO and U O . The measurement of MOX(UO -PuO ) powders
3 3 8 2 2
refers to plutonium dioxide. When conditions described are fulfilled, modifications using other adsorbing
gases are included.
2 2
The method is relevant as long as the expected value is in the range from 1 m /g to 10 m /g for uranium
2 2
dioxide powders, in the range from 0.1 m /g to 45 m /g for plutonium dioxide powders.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 9277:2022, Determination of the specific surface area of solids by gas adsorption — BET method
3 Terms and definitions
No terms and definitions are listed in this document.
ISO
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