EN ISO 6863:2026

• Abstract:

  This document specifies a method which applies to the preparation and validation of the standard materials generally called “large size spikes” with an uncertainty suitable for international nuclear safeguards used for measuring the content of plutonium and/or uranium by isotope dilution mass spectrometry. ; This measurement methodology can be applied to input solutions of irradiated Magnox and light water reactor fuels (boiling water reactor or pressurized water reactor); in final products at spent-fuel reprocessing plants; in feed and products of mixed oxide of plutonium and uranium (MOX); and in uranium fuel fabrication

• Status: Published
• Publication Date: 18-Aug-2026
• 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: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 19-Aug-2026
• Due Date: 19-Jun-2028
• Completion Date: 19-Aug-2026
• Ref Project: SIST EN ISO 6863:2026 - Nuclear fuel technology - Preparation of spikes for isotope dilution mass spectrometry (IDMS) (ISO 6863:2024)

EN ISO 6863:2026 is a CEN European Standard that adopts ISO 6863:2024. It specifies how to prepare and validate spikes for isotope dilution mass spectrometry (IDMS) so plutonium and/or uranium content can be measured with uncertainty suitable for international nuclear safeguards. The document is intended for laboratories and organisations that prepare, check, store, and use these spikes in nuclear fuel technology.

What does EN ISO 6863:2026 specify?

EN ISO 6863:2026 specifies a method for preparing and validating standard materials generally called “large size spikes” for IDMS measurement of plutonium and/or uranium. It is written for use where measurement uncertainty matters in safeguards work and in nuclear fuel cycle analysis.

The scope names four main application areas:

• input solutions of irradiated Magnox and light water reactor fuels
• final products at spent-fuel reprocessing plants
• feed and products of mixed oxide of plutonium and uranium (MOX)
• uranium fuel fabrication

The document is organised into clauses on scope, normative references, terms and definitions, principle, spike design, reference materials and reagents, apparatus, preparation of spikes, validation, storage, and a bibliography. Clause 8 gives the practical preparation routes for different spike types, while Clause 9 and Clause 10 deal with validation and storage.

What are the key requirements of EN ISO 6863:2026?

EN ISO 6863:2026 sets out how to design, prepare, validate, and store spikes so their isotopic composition and content are suitable for IDMS. In practice, the standard is as much about control of uncertainty and traceability as it is about the chemistry of making the spike.

1) Use the IDMS principle correctly

Clause 4 explains that IDMS compares the isotopic composition of the sample with the sample after addition of a spike, then calculates element content from that difference. The spike must have an isotopic composition significantly different from the unspiked sample. In practice, this means the lab must choose spike isotopes that are absent or only minimally present in the sample, or the final result becomes less reliable.

2) Design the spike for the sample and the target uncertainty

Clause 5 requires spike design to be optimised for the sample to be analysed and for the International Target Values (ITVs) used in safeguards work. The document notes two basic spike forms: solution spikes and dry spikes. Clause 5.1 gives a calculation approach for choosing the spike-to-sample ratio and isotopic composition, so the user can tune the spike instead of using a one-size-fits-all mixture.

3) Treat uncertainty as part of the spike design

Clause 5.2 says spike uncertainty comes from the Certified Reference Material (CRM), the analytical balance, and the equipment and tracer used for characterisation or standardisation. These contributions are combined and expressed as expanded uncertainty with coverage factor k = 2. For the reader, that means the spike is not just prepared - its uncertainty budget must also be worked out and documented.

4) Use suitable reference materials, reagents, and apparatus

Clause 6 and Clause 7 define the materials and equipment needed. The reference materials include uranium and plutonium CRMs, plus secondary standard materials traceable to CRMs or verified by intercomparison. The reagents listed are ordinary analytical-grade acids, water meeting ISO 3696 grade 1, ethanol, acetone, and potassium carbonate solution. The apparatus includes mass spectrometry equipment in accordance with ISO 8299, glove boxes, an analytical balance, pipettes, hot plate, stock bottles, and common laboratory ware. In practice, this means the method assumes controlled handling, accurate weighing, and safe containment of radioactive materials.

5) Follow the correct preparation route for each spike type

Clause 8 gives separate preparation routes for:

• large-sized dried (LSD) spikes
• uranium liquid spikes
• uranium dried spikes
• plutonium liquid spikes
• plutonium dried spikes
• uranium-plutonium mixed spikes

For LSD spikes, uranium and plutonium stock solutions are prepared from CRMs, mixed to the desired composition, aliquoted, and dried in vials. For uranium or plutonium spikes, the document gives liquid and dried forms. For mixed spikes, both elements are prepared together when both are routinely measured. The practical point is that the user selects the preparation route that matches the later IDMS measurement task.

6) Control mass, evaporation, and drying steps carefully

Clause 8 repeatedly requires weighing before and after transfers, and it uses an evaporation factor to correct for mass loss during storage or handling. Dried spikes are heated to dryness so they form a glassy deposit that adheres to the vial bottom. The standard also warns that crystals or flaking can affect measurement, so drying and reconditioning are part of the method, not a side issue.

7) Validate every spike against measured values

Clause 9 requires the prepared stock solutions and spikes to be validated by reliable measurement methods, with measured values compared against make-up values from the certified masses and dilution or evaporation factors. The clause points to ISO 8299 for isotopic analysis and IDMS, ISO 12183 for controlled-potential coulometry, and ISO 7097-1, ISO 7097-2, or ISO 8298 for titration. It also recommends QC samples and, for statistical evaluation of homogeneity and stability, ISO 17034 and ISO Guide 35. In practice, this means the prepared spike must be checked, not assumed to be correct.

8) Store and recondition spikes to protect stability

Clause 10 requires solution spikes to be kept in sealed ampoules or tightly capped containers, with mass checks used to track evaporation. Dried spikes should be stored in a stable place, and the document warns that long storage can lead to crystallisation and flaking. Clause 10.3 gives a reconditioning step for uncoated dried spikes, where the material is re-dissolved and dried again before transport. That matters because the physical form of the spike can affect the measurement result.

What terms does EN ISO 6863:2026 define?

EN ISO 6863:2026 defines the main spike types used in the method.

• Solution spike - a nitric acid solution with accurately quantified uranium and/or plutonium content and isotopic composition; it is one of the reference materials used in IDMS.
• Dried spike - a solution spike that has been aliquoted into a glass vessel and dried; it is used when a solid dose is more practical than a liquid.
• Large-sized dried spike (LSD spike) - a dried spike containing both uranium and plutonium in milligram size, originally developed for high-concentration input solutions.
• Isotope dilution mass spectrometry (IDMS) - the measurement approach that determines element content from the change in isotopic composition after adding a spike.
• Thermal ionization mass spectrometry (TIMS) - the mass spectrometric technique used in the IDMS principle described in Clause 4.
• Certified Reference Material (CRM) - a certified material used as the starting point for spike preparation and for uncertainty and traceability control.
• International Target Value (ITV) - the target uncertainty level used in safeguards-related IDMS work and referenced in spike design.

Who uses EN ISO 6863:2026?

EN ISO 6863:2026 is used by laboratories and technical teams that prepare and check uranium and plutonium spikes for IDMS. Typical users include nuclear fuel analysts, safeguards laboratories, reference material producers, and quality or metrology staff in fuel cycle organisations.

It is relevant to work on irradiated fuel solutions, spent-fuel reprocessing streams, MOX feed and product materials, and uranium fuel fabrication. Users apply it when they need a spike with known isotopic composition, a controlled uncertainty budget, and a storage approach that keeps the material fit for measurement.

What changed in EN ISO 6863:2026 from the previous edition?

EN ISO 6863:2026 takes over ISO 6863:2024 as EN ISO 6863:2026 without modification. The European foreword states that the ISO text has been approved by CEN as the European Standard unchanged.

Which standards are used with EN ISO 6863:2026?

EN ISO 6863:2026 refers to several standards that support the method:

• ISO 3696 - specifies grade 1 water for analytical work, used for solution preparation and rinsing.
• ISO 8299 - gives the mass spectrometry method for isotopic and elemental uranium and plutonium analysis, and supports the IDMS measurements.
• ISO/IEC Guide 98-3 - provides the Guide to the Expression of Uncertainty in Measurement, used for combining spike uncertainties.
• ISO 12183 - gives controlled-potential coulometric measurement of plutonium, used as a validation method.
• ISO 7097-1 and ISO 7097-2 - give titrimetric methods for uranium, used for validating uranium stock solutions.
• ISO 8298 - gives potentiometric titration for milligram amounts of plutonium in nitric acid solutions, used for plutonium validation.
• ISO 17034 and ISO Guide 35 - support reference material production, homogeneity, stability, and statistical evaluation.
• ASTM C1128 - gives guidance for preparing working reference materials for nuclear fuel cycle materials, cited as background for secondary materials.

What does the EN ISO 6863:2026 document contain?

EN ISO 6863:2026 contains the principle of IDMS, design guidance for spikes, lists of reference materials and reagents, apparatus requirements, and step-by-step preparation routes for uranium, plutonium, LSD, and mixed spikes. It also contains validation methods, storage guidance, and a reconditioning procedure for dried spikes.

The document includes calculation steps for spike optimisation, mass-balance checks such as evaporation factors, and procedures for homogenising, drying, sealing, and reweighing prepared spikes. It also points users to specific analytical methods for checking uranium and plutonium content and isotopic composition before the spike is used for routine IDMS work.

SLOVENSKI STANDARD
01-oktober-2026
Tehnologija jedrskega goriva - Priprava konic za masno spektrometrijo z
izotopskim redčenjem (IDMS) (ISO 6863:2024)
Nuclear fuel technology - Preparation of spikes for isotope dilution mass spectrometry
(IDMS) (ISO 6863:2024)
Kernbrennstofftechnologie - Vorbereitung von Spikes für die
Isotopenverdünnungsmassenspektrometrie (IDMS) (ISO 6863:2024)
Technologie du combustible nucléaire - Préparation de traceurs pour les analyses par
spectrométrie de masse avec dilution isotopique (IDMS) (ISO 6863:2024)
Ta slovenski standard je istoveten z: EN ISO 6863:2026
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 6863
EUROPEAN STANDARD
NORME EUROPÉENNE
August 2026
EUROPÄISCHE NORM
ICS 27.120.30
English Version
Nuclear fuel technology - Preparation of spikes for isotope
dilution mass spectrometry (IDMS) (ISO 6863:2024)
Technologie du combustible nucléaire - Préparation de Kernbrennstofftechnologie - Vorbereitung von Spikes
traceurs pour les analyses par spectrométrie de masse für die Isotopenverdünnungsmassenspektrometrie
avec dilution isotopique (IDMS) (ISO 6863:2024) (IDMS) (ISO 6863:2024)
This European Standard was approved by CEN on 10 August 2026.

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
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 6863:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO 6863:2024 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 6863:2026 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 February 2027, and conflicting national standards
shall be withdrawn at the latest by February 2027.
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.
Any feedback and questions on this document should be directed to the users’ national standards body.
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 6863:2024 has been approved by CEN as EN ISO 6863:2026 without any modification.

International
Standard
ISO 6863
First edition
Nuclear fuel technology —
2024-11
Preparation of spikes for isotope
dilution mass spectrometry (IDMS)
Technologie du combustible nucléaire — Préparation de traceurs
pour les analyses par spectrométrie de masse avec dilution
isotopique (IDMS)
Reference number
ISO 6863:2024(en) © ISO 2024
ISO 6863:2024(en)
© ISO 2024
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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO 6863:2024(en)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Design of spikes . 2
5.1 Optimization of spikes .2
5.2 Uncertainty of spikes .3
6 Reference materials and reagents . 3
6.1 Reference materials .3
6.1.1 Uranium reference materials .3
6.1.2 Plutonium reference materials .3
6.1.3 Secondary standard materials.4
6.2 Other chemical reagents .4
7 Apparatus . 4
8 Preparation of spikes . 5
8.1 Large-sized dried (LSD) spikes .5
8.1.1 Preparation of uranium stock solution .5
8.1.2 Preparation of plutonium stock solution .6
8.1.3 Preparation of mixed stock solution . .7
8.1.4 Taking mixed solution aliquots .8
8.1.5 Drying .9
8.1.6 Stabilization of LSD spike .9
8.2 Uranium spikes .9
8.2.1 Uranium liquid spikes .9
8.2.2 Uranium dried spikes .10
8.3 Plutonium spikes .10
8.3.1 Plutonium liquid spikes .10
8.3.2 Plutonium dried spikes .10
8.4 Uranium – plutonium mixed spikes .10
9 Validation of spikes .11
9.1 General .11
9.2 LSD spikes .11
9.3 Uranium spikes .11
9.4 Plutonium spikes . 12
9.5 Uranium-plutonium mixed spikes. 12
10 Storage of spikes .12
10.1 Storing solution spikes . 12
10.2 Storing dried spikes . 12
10.3 Reconditioning of dried spikes . 12
Bibliography .13

iii
ISO 6863:2024(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.
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 6863:2024(en)
Nuclear fuel technology — Preparation of spikes for isotope
dilution mass spectrometry (IDMS)
1 Scope
This document specifies a method which applies to the preparation and validation of the standard materials
generally called “large size spikes” with an uncertainty suitable for international nuclear safeguards used
for measuring the content of plutonium and/or uranium by isotope dilution mass spectrometry.
This measurement methodology can be applied to input solutions of irradiated Magnox and light
water reactor fuels (boiling water reactor or pressurized water reactor); in final products at spent-fuel
reprocessing plants; in feed and products of mixed oxide of plutonium and uranium (MOX); and in uranium
fuel fabrication.
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 3696, Water for analytical laboratory use — Specification and test methods
ISO 8299, Nuclear fuel technology — Determination of the isotopic and elemental uranium and plutonium
concentrations of nuclear materials in nitric acid solutions by thermal-ionization mass spectrometry
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
solution spike
nitric acid solutions with accurately quantified uranium and/or plutonium content and isotopic composition
Note 1 to entry: One of the reference materials for IDMS.
3.2
dried spike
prepared by aliquoting solution spikes (3.1) into glass vessels and then drying
Note 1 to entry: One of the reference materials for IDMS.
3.3
large-sized dried spike
LSD spike
dried spike containing both uranium and plutonium in milligram size, were originally developed to analyse
high concentrated input solution
Note 1 to entry: One of the reference materials for IDMS.

ISO 6863:2024(en)
Note 2 to entry: The LSD spikes can simplify the sample preparation process with only one spiking step to the sample,
which also contains uranium and plutonium, and reduce measurement uncertainty by less dilution factor than smaller
sized spikes.
4 Principle
Element content measurement using thermal ionization mass spectrometry (TIMS) is made on a sample
and mixture of the sample and a spike, consisting of an enriched isotope of the element to be analysed and
determine element content by calculating the difference of isotopic composition before and after spike
mixture. This method of measuring an element’s content is called isotope dilution mass spectrometry (IDMS).
The isotopic compositions of the sample and spike is required to be significantly different. Therefore, it
is desirable that spikes are composed of isotopes that are not present, or only minimally present, in the
unspiked sample. It is necessary that the isotopic composition and the content of spikes be known or
measured accurately and has small uncertainties because it reflects to the uncertainty of the final results,
element content.
Chemically-pure compounds of separated plutonium or uranium isotopes are dissolved to prepare stock
solutions of spikes, in general terms, in 3 mol/l to 7 mol/l nitric acid to obtain an optimized content based
on its design to obtain reliable results. Aliquots of the plutonium and uranium spike stock solutions can be
mixed to prepare mixed spikes. Aliquoted spikes are used for IDMS in solution state or after dried.
5 Design of spikes
As the uncertainty to be considered in determining the reliability of nuclear fuel material analysis techniques
[1]
for safeguards, International Target value (ITV) is decided for IDMS. It is desirable that spikes are used for
IDMS after being optimized for the sample to be analysed. Different target values are set depending on the
environment to be measured and spikes used. Spikes shall be designed so that measurement by IDMS can
achieve the appropriate ITVs.
There are two types of spikes: solution spikes and dry spikes. Basically, either spike is fine. In general, choose
which spike to prepare according to user needs.
5.1 Optimization of spikes
In IDMS, when the isotopic composition in the unknown sample and in the spike are significantly different,
the measurement accuracy become higher. On the other hand, the isotopic composition of available certified
reference materials for preparing spikes are limited. Therefore, it is important to design the plutonium and/
or uranium composition of spikes by evaluating, in advance, the isotopic composition and the amounts of
elements of spikes that can be obtained sufficient accuracy. The following sentences describe an example of
calculations for optimizing spikes.
The following Formula (1) can be obtained by partially differentiating the theoretical equation of IDMS with
[2]
sample to spike mass ratio, p .
2 22 2 2
1+ppK1+γ R
σγ()p 1 ()11+pK()+ R () ()
 
22 S 22
T
=⋅ ⋅+ε R ⋅ε R
S T
 
2 22 2 2
p
 
p
()RR− ()1+γKR ()RR− ()1+γKR
ST S ST T
[]pR ()11+γγKR ++RK()Rp[]()11+γγKR ++()KR
TS ST ST 2
+⋅ ⋅ε
2 22 2 2
p RR− 11+γγKR + KR
() () ()
ST TS
γ RR−
()
TS
+ ⋅σ (1)
K
2 2
()11+γγKR ()+ KR
TS
ISO 6863:2024(en)
where
σ ()p
is the standard deviation of p;
R is the isotopic ratio of sample;
S
R is the isotopic ratio of spike;
T
γ is absolute mass ratio of second to first major isotope;
K is mass discrimination factor;
ε
is standard deviation of for isotopic ratio measurement.
By replace p to sample to spike number of atoms ratio, q and putting γ equal to unity. If K equal to 1,
Formula (1) is described as following Formula (2):
2 22 2 2
σ ()q ()11+qR()+ ()1+q ()11+R
  1
T 22 S 22
=⋅ ⋅+ε R ⋅ε R
S T
 
2 22 2 2
q
  q
()RR− ()1+R ()RR− ()1+R
ST S ST T
qR 11+RR++Rq 11+RR++
1 []() () []() ()
TS ST ST 2
+⋅ ⋅ε (2)
2 2 2 2
q
()RR− ()1+R ()11+R
ST T S
2 2
Where, the value “[σ(q)/q] /ε ” means the size of the error depending on the mixing ratio of spike and sample,
and from this, the amount of spike to sample and/or isotopic ratio is calculated and able to be optimized.
5.2 Uncertainty of spikes
The uncertainty of spikes can be combined from the Certified Reference Material (CRM), analytical balance,
and also from the equipment and tracer used for instrumental analysis for the purpose of characterization
or standardization. These individual uncertainties should be combined and should be given as expanded
uncertainty when the coverage factor k = 2. The uncertainty can be calculated in accordance to the
[3]
ISO/IEC Guide 98-3 .
6 Reference materials and reagents
The reagents listed below are prepared from analytical grade reagents unless it is specified otherwise.
6.1 Reference materials
Examples of reference material for preparing spike are shown below.
6.1.1 Uranium reference materials
a) natural uranium metal CRM of purity with an elemental content certified to ±0,05 % (k = 2) or better,
such as NBL-CRM-112A (e.g. NBS-960D), EC-101, CETAMA-MU2.
b) other uranium metal, powder or pellet CRM of purity with an elemental content certified to ±0,05 %
(k = 2) or better, such as NBL-CRM-116A (HEU metal), CRM-125A (UO pellet) and CRM-129 (U O
2 3 8
powder). CRM solution can also be available as a source. Abundance of the major isotope of uranium
shall be greater than or equal to 80 %.
6.1.2 Plutonium reference materials
Plutonium metal CRM with an elemental content certified to ±0,05 % (k = 2) or better, such as NBL-CRM-126
or 126A, EC-201 or CETAMA-MP2. Abundance of the major isotope of plutonium shall be greater than or
equal to 80 %.
ISO 6863:2024(en)
6.1.3 Secondary standard materials
For both plutonium and uranium, secondary standard materials in solution or in solid and traceable to CRMs
or verified by means of a laboratory intercomparison can also be used. The values should be certified to
±0,05 % (k = 2) or better.
6.2 Other chemical reagents
The reagents listed below are in analytical grade and other reagents could also be used if results are
confirmed to be equivalent.
6.2.1 Nitric acid solutions, c(HNO ) = 1 mol/l, 3 mol/l, 4 mol/l, 7 mol/l to 8 mol/l and other.
6.2.2 Hydrochloric acid solutions, c(HCl) = 0,1 mol/l, 3 mol/l, 4 mol/l, 12 mol/l and other are applicable
for dissolution and etching for uranium metal and/or plutonium metal.
6.2.3 Hydrofluoric acid, c(HF) = 27 mol/l. HF can mix with nitric acid solution before use.
WARNING — Hydrofluoric acid is strongly corrosiv
...