oSIST prEN ISO 12800:2026

• Abstract:

  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.

• Status: Not Published
• Public Enquiry End Date: 24-Mar-2026
• ICS: 27.120.30 - Fissile materials and nuclear fuel technology
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 16-Jan-2026
• Due Date: 05-Jun-2026
• Completion Date: 27-Mar-2026
• Ref Project: FprEN 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/FDIS 12800:2026)

• Revises: SIST 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

oSIST prEN ISO 12800:2026 is an international standard developed by CEN, aligning with ISO/DIS 12800:2026, which provides comprehensive guidelines for measuring the specific surface area of uranium dioxide (UO₂) and plutonium dioxide (PuO₂) powders using the BET method. This standard addresses both volumetric and gravimetric techniques based on nitrogen gas adsorption and offers procedures that may be adapted for similar materials, such as U₃O₈, mixed oxide (MOX) powders, and other relevant forms like green pellets. The outlined methods are applicable particularly within a specific surface area range suitable for nuclear fuel materials, ensuring consistent quality and reliable data for fuel fabrication processes.

Key Topics

• BET Method Fundamentals: The standard summarizes how the BET (Brunauer-Emmett-Teller) method is applied to determine the specific surface area by adsorbing a monomolecular layer of nitrogen gas on the powder surface under controlled conditions.
• Sample Preparation: Detailed guidance is provided for pre-treating uranium dioxide and plutonium dioxide powders, including removing surface contaminants and optimizing heating conditions to avoid sintering or chemical changes.
• Measurement Techniques: Both volumetric and gravimetric measurements are described, detailing the sample requirements and the principle behind each method.
• Calculation and Expression of Results: The document explains how to derive surface area from adsorption data using multi-point and single-point BET calculations, emphasizing the importance of accuracy and repeatability.
• Procedure Variations: Adaptations for alternative gases and other materials with comparable surface properties are included, broadening the scope for research and industrial application.

Applications

oSIST prEN ISO 12800:2026 is primarily applicable in the following areas of nuclear fuel technology:

• Nuclear Fuel Fabrication: Ensuring the homogeneity and reactivity of uranium dioxide and plutonium dioxide powders, which is essential for safe and efficient nuclear fuel production.
• Quality Control: Providing standardized testing for surface area measurement, critical for characterizing raw materials and verifying batch consistency.
• Research and Development: Facilitating the comparison of alternative fuel and mixed oxide (MOX) powders by applying uniform methods for surface area assessment.
• Regulatory Compliance: Supporting adherence to international and national regulations by harmonizing the measurement techniques and reporting requirements.
• Advanced Powder Characterization: Enabling manufacturers and laboratories to assess not only UO₂ and PuO₂ but also other powders and pellets with similar surface characteristics, provided they meet the stipulated adsorption and material criteria.

Related Standards

• ISO 9277:2022: Determination of the specific surface area of solids by gas adsorption - BET method. This is referenced for foundational BET procedures and calculation methods.
• ISO/IEC Guide 98-3:2008: Guidance on the expression of measurement uncertainty, ensuring the reliability and comparability of reported results.
• National and International Nuclear Fuel Standards: oSIST prEN ISO 12800:2026 integrates with wider frameworks of fissile material and nuclear fuel technology standards (ICS 27.120.30).

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Keywords: nuclear fuel technology, specific surface area, uranium dioxide powder, plutonium dioxide powder, BET method, nitrogen adsorption, CEN standard, ISO 12800, powder characterization, MOX, fuel fabrication, surface area measurement, quality control, nuclear standards.

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.
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BEING ACCEPTABLE FOR INDUSTRIAL,
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USER PURPOSES, DRAFT INTERNATIONAL
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POTENTIAL TO BECOME STANDARDS TO
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NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED
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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
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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
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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
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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 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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