SIST EN ISO 8299:2021
(Main)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 (ISO 8299:2019)
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 (ISO 8299:2019)
This document specifies a method for the determination of the isotopic and elemental uranium and plutonium concentrations of nuclear materials in nitric acid solutions by thermal-ionization mass spectrometry.
The method applies to uranium and plutonium isotope composition and concentration measurement of irradiated Magnox and light water reactor fuels (boiling water reactor or pressurized water reactor), in final products at spent-fuel reprocessing plants, and in feed and products of MOX and uranium fuel fabrication. The method is applicable to other fuels, but the chemical separation and spike solution are, if necessary, adapted to suit each type of fuel.
Kernbrennstofftechnologie - Bestimmung des Isotopengehaltes und der natürlichen Uran- und Plutoniumkonzentrationen kerntechnischer Werkstoffe in Salpetersäure-Lösungen durch Massenspektrometrie mit Wärmeionisation (ISO 8299:2019)
Technologie du combustible nucléaire - Détermination de la teneur isotopique et des concentrations en matériaux nucléaires de l'uranium et du plutonium dans une solution d'acide nitrique par spectrométrie de masse à thermoionisation (ISO 8299:2019)
Le présent document spécifie une méthode pour la détermination de la teneur isotopique et de la concentration d'uranium et du plutonium dans les matières nucléaires en solution d'acide nitrique par spectrométrie de masse à thermo-ionisation.
La méthode s'applique à la composition isotopique de l'uranium et du plutonium et au mesurage de la concentration des combustibles usés dans les réacteurs Magnox et à eau légère (réacteurs à eau bouillante ou à eau pressurisée), dans les produits sortants des usines de retraitement des combustibles usés, ainsi que dans les matières premières et les produits de fabrication de combustibles MOX et UOX. La méthode est applicable à d'autres combustibles, mais la séparation chimique et la solution de traçage sont adaptées à chaque type de combustible, le cas échéant.
Tehnologija jedrskih goriv - Ugotavljanje deleža izotopov ter koncentracije jedrskih snovi elementarnega urana in plutonija v raztopinah dušikove kisline s termoionizacijsko masno spektrometrijo (ISO 8299:2019)
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-april-2021
Tehnologija jedrskih goriv - Ugotavljanje deleža izotopov ter koncentracije jedrskih
snovi elementarnega urana in plutonija v raztopinah dušikove kisline s
termoionizacijsko masno spektrometrijo (ISO 8299:2019)
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 (ISO 8299:2019)
Technologie du combustible nucléaire - Détermination de la teneur isotopique et des
concentrations en matériaux nucléaires de l'uranium et du plutonium dans une solution
d'acide nitrique par spectrométrie de masse à thermoionisation (ISO 8299:2019)
Ta slovenski standard je istoveten z: EN ISO 8299:2021
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 8299
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2021
EUROPÄISCHE NORM
ICS 27.120.30
English Version
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 (ISO 8299:2019)
Technologie du combustible nucléaire - Détermination
de la teneur isotopique et des concentrations en
matériaux nucléaires de l'uranium et du plutonium
dans une solution d'acide nitrique par spectrométrie
de masse à thermoionisation (ISO 8299:2019)
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 8299:2021 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
The text of ISO 8299:2019 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 8299:2021 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 8299:2019 has been approved by CEN as EN ISO 8299:2021 without any modification.
INTERNATIONAL ISO
STANDARD 8299
Third edition
2019-01
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
Technologie du combustible nucléaire — Détermination de la
teneur isotopique et des concentrations en matériaux nucléaires de
l'uranium et du plutonium dans une solution d'acide nitrique par
spectrométrie de masse à thermoionisation
Reference number
ISO 8299:2019(E)
©
ISO 2019
ISO 8299:2019(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.
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Phone: +41 22 749 01 11
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Published in Switzerland
ii © ISO 2019 – All rights reserved
ISO 8299:2019(E)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reference materials and reagents . 2
5.1 Spikes and reference materials . 2
5.2 Other chemical reagents . 3
5.3 Resin, applicable for separation/purification of Pu and U . 4
5.3.1 General. 4
5.3.2 Preparation of resin . 4
6 Apparatus . 5
7 Apparatus for mass spectrometry . 6
8 Sample preparation . 6
8.1 Subsampling and spiking . 6
8.1.1 Pellet or powder samples . 7
8.1.2 Concentrated nuclear fuel solution samples (such as reprocessing solution) . 7
8.1.3 Plutonium nitrate solution samples (such as product solution from a
reprocessing plant) . 7
8.1.4 Dried nitrate samples . 8
8.2 Chemical valency adjustment . 8
8.2.1 Valence adjustment with ferrous solution . 8
8.2.2 Valence adjustment with hydrogen peroxide . 8
8.3 Sample separation/purification . 9
8.3.1 Ion exchange with anion-exchange resin . 9
8.3.2 Purification with extraction separation resins (see 5.3.1.2) .10
8.4 Replicate treatments .10
9 Filaments preparation .10
9.1 Degassing of filaments .10
9.2 Sample loading .10
9.2.1 Normal sample loading .10
9.2.2 Graphite loading technique .10
9.2.3 Resin-bead loading on single filaments for Pu samples .11
9.3 Filament mounting (filament assemblies preparation) .11
10 Instrument calibration .11
10.1 Mass calibration .11
10.2 Gain calibration for Faraday multi-detectors .11
10.3 Faraday detector calibration .11
10.4 Mass discrimination calibration .12
11 Isotopic mass spectrometric measurements .12
11.1 Total evaporation measurements using a single or double filament assembly and a
multi-Faraday collector system .12
11.2 Bias correction method using a double filament assembly and a multi-Faraday
collector system .13
12 Calculation of the results .13
12.1 Calculation of ion current intensities .13
12.2 Calculation of mean, weighted mean and standard deviation on a set of ratios x ,
i
(i = 1…N) .14
12.3 Mass discrimination correction .14
12.4 Calculation of the atomic percent abundance A .14
i
ISO 8299:2019(E)
12.5 Calculation of the isotopic mass percent W .15
j
12.6 Calculation of concentration .15
12.7 Isotope decay correction .16
13 Blanks .16
14 Quality control .16
15 Measurement uncertainty .17
15.1 Elemental assay .17
15.2 Isotopic analysis .17
16 Interferences .18
Annex A (normative) Preparation and standardization of spike solutions .19
Bibliography .25
iv © ISO 2019 – All rights reserved
ISO 8299:2019(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
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 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).
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 ISO/TC 85, Nuclear energy, nuclear technologies, and radiological
protection, Subcommittee SC 5, Nuclear installations, processes and technologies.
This third edition cancels and replaces the second edition (ISO 8299:2005), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— the procedure for the preparation of resin used for separation and purification of the samples has
been added in 5.3;
— sample preparation procedure from pellet, powder and other material forms to the solution has
been added in 8.1;
— uncertainty of the measurement is considered in Clause 15 instead of repeatability and accuracy.
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.
INTERNATIONAL STANDARD ISO 8299:2019(E)
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
1 Scope
This document specifies a method for the determination of the isotopic and elemental uranium and
plutonium concentrations of nuclear materials in nitric acid solutions by thermal-ionization mass
spectrometry.
The method applies to uranium and plutonium isotope composition and concentration measurement of
irradiated Magnox and light water reactor fuels (boiling water reactor or pressurized water reactor),
in final products at spent-fuel reprocessing plants, and in feed and products of MOX and uranium fuel
fabrication. The method is applicable to other fuels, but the chemical separation and spike solution are,
if necessary, adapted to suit each type of fuel.
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 10980, Validation of the strength of reference solutions used for measuring concentrations
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 Principle
The described method is based on isotope ratio measurements by thermal ionization mass spectrometry
(TIMS). TIMS analysis requires isotope separation of different elements that have the same or similar
238 241 238
masses as an isotope of the element being measured, such as U and Am influences Pu and
Pu. Separation method for Pu and U using columns purifications are described in Clause 8. Other
separation methods may be used provided that they lead to a separation of similar quality. Column
extraction chromatography described in ISO 15366 (all parts) is an example of a suitable alternative.
The described method consists of two separate TIMS measurements:
a) Isotopic measurement
One measurement is made to determine the isotopic composition of the element in the sample. The
Pu isotope abundance is determined by combining mass spectrometry following the present
method and alpha spectrometry as described in ISO 11483, if the interference of the isobar U is
not eliminated by chemical separation.
ISO 8299:2019(E)
b) Element concentration measurement
A second measurement is made on a sample and a spike mixture consisting of an artificially
enriched isotope of the element to be analysed. The sample element concentration is determined
by calculating the difference of isotopic composition before and after the sample spike mixture.
This method of measuring an element’s concentration is called isotope dilution mass spectrometry
(IDMS). The spiking can be made using a spike isotope that either is present, only minimally
233 244
present, or absent in the non-spiked sample. The use of U or Pu spikes can eliminate the
need for an isotope measurement in the non-spiked sample to determine uranium and plutonium
concentration. Although it is normally of interest to measure both the isotopic composition and
the element concentration. It is also more common to use a less expensive spike made from Pu,
240 242 235
Pu, Pu or U. Accurate measurements made on the masses of the sample and spike in the
mixture are required for the IDMS method. It is necessary that the isotopic composition and the
concentration of the spike be known or measured accurately and has small uncertainties. The IDMS
calculations are described in 12.6.
The IDMS method includes the following steps:
— sample dilution by mass if necessary;
— aliquoting and spike addition by mass;
— valency adjustment and isotope-exchange chemistry resulting in an isotopically equilibrated
mixture;
— chemical purification/separation;
— sample loading and oxidation on filaments;
— isotope ratio measurements by TIMS on spiked and non-spiked fractions.
This procedure describes two methods of TIMS measurements:
— Total evaporation (TE), multi-Faraday collector measurements. This method consumes the
whole sample. The ion beam of the element is totally collected. There are several advantages
with this method. It allows precise measurements of small sample amounts, can easily
calculate the mass discrimination factor and is easily adopted for automatic measurements.
The TE method relies almost entirely on separate measurements of standards to calculate
measurement uncertainty and precision.
— Bias correction method (conventional multi-Faraday collector measurements). In the bias
correction method, the different isotopes are collected in a limited period of the sample
evaporation. The data are collected in blocks, typically containing 10 to 20 sets (scans) of
measurements. With the bias correction method, it is possible to calculate the precision
of the ratio measurements within each block and between blocks and to use the internal
precision data to assess measurement quality on a filament-by-filament basis.
5 Reference materials and reagents
The solutions listed below are prepared from analytical grade reagents unless it is specified otherwise.
5.1 Spikes and reference materials
Reference materials and reference solutions to confirm instrument performance and spikes for the
isotope-dilution are shown below.
5.1.1 Uranium standard reference solution, prepared by one of the following methods:
— from natural uranium metal with an elemental concentration certified to 0,05 % (k = 2) or better,
such as NBL-CRM-112A (ex NBS-960D), EC-101, CETAMA-MU-2;
2 © ISO 2019 – All rights reserved
ISO 8299:2019(E)
— from other uranium metal, powder or pellet with an elemental concentration certified to 0,05 %
(k = 2) or better, such as NBL-CRM-116-A (HEU metal), CRM-125-A(UO pellet) and CRM-129 (U O
2 3 8
powder).
5.1.2 Plutonium standard reference solution, prepared by one of the following methods:
— plutonium metal with an elemental concentration certified to 0,05 % (k = 2) or better, such as NBL-
CRM-126 or 126-A, EC-201, CETAMA-MP2 or NBS-949, with a Pu isotopic abundance of 90 % or
more, certified to 0,05 % (k = 2) or better; the same isotopic abundance requirements apply if Pu,
242 244
Pu or Pu is used as the spike isotope;
240 242 244
— certified plutonium standard solution enriched in Pu, Pu or Pu isotope in case where 97 %
enriched Pu is used as a spike.
For both U and Pu standard reference solutions, other standard solutions traceable to these CRMs or
verified by means of a laboratory intercomparison can also be used. See Annex A and ISO 10980 for the
preparation and validation of these solutions.
5.1.3 Uranium spike, of certified isotopic and chemical composition, such as IRMM-040, IRMM-
041, IRMM-042, NBL-CRM-111A (ex NBS-995), NBL-CRM-135 or NBL-CRM-U930D.
5.1.4 Plutonium spike, of certified isotopic and chemical composition, such as IRMM-041, IRMM-
242 244
043, IRMM-044, IRMM-049, NBL-CRM-130 ( Pu nitrate), NBL-CRM-131 ( Pu nitrate, ex NBS-996),
240 242 244 239
NBL-CRM-144 (mixture of Pu, Pu, and Pu nitrates), NBL-CRM-126 (97 % enriched Pu metal),
239 239
NBL-CRM-126A (93 % enriched Pu metal) or CETAMA-MP2 (97 % enriched Pu metal).
5.1.5 Mixed uranium/plutonium spike solution, of certified isotopic and chemical composition,
233 242 235
such as IRMM-046 (mixed U/ Pu spike). Also, nitrate solution containing 0,2 - 0,3 mg/g U and
1 - 2 μg/g Pu, prepared from reference materials such as NBL-CRM-135 or NBL-CRM-U930D and
IRMM-049 or NBL-CRM-130.
5.1.6 Large-size dried (LSD) spike, of certified isotopic and chemical composition and dried,
such as IRMM-1027 series, containing about 50 mg of 20 % enriched U and 1 mg or 2 mg of 90 % or
higher enriched Pu.
235 242
5.1.7 Mixed uranium/plutonium spike, containing 0,2 - 0,3 mg/g of U and 1 - 2 µg/g of Pu in
nitric acid, 7 mol/l, prepared from certified materials such as NBL-CRM-135 or NBL-CRM-U930-D, and
IRMM-049 or NBL-CRM-130.
NOTE If certified spikes 5.1.3, 5.1.4, 5.1.5, 5.1.6 or 5.1.7 are not available, an in-house LSD spike, prepared by
mixing uranium CRMs (such as NBL-CRM-112A (natural uranium) and/or NBL-CRM-116 or 116A) and plutonium
CRM (NBL-CRM-126 or 126A or CETAMA-MP2) or by reference solutions (see 5.1.1 and 5.1.2) can also be applied.
The desired spikes can be prepared and standardized in accordance with ISO 10980. Suitable
procedures are described in Annex A.
Hereafter, dried spike, solution spike and LSD spike are called spike.
5.1.8 Certified isotopic reference materials, covering the isotopic range of interest and certified
to 0,1 % or better for the major isotope ratios, such as IRMM-290, NBL-CRM-128, NBL-CRM-136, NBL-
CRM-137 (ex NBS-947), NBL-CRM-144, NBL-CRM-122, CEA-MIRF-01, AEAT-UK-Pu3 for plutonium, and
IRMM-072, EC-NRM-199, NBL-CRM-010, NBL-CRM-030, NBL-CRM-117, NBL-CRM-U005A to NBL-CRM-
U930-D, IRMM-183 to IRMM-187, CEA-MIRF-02, AEAT-UK-U2 for uranium.
5.2 Other chemical reagents
In principle, oxidation-reduction reagents should be prepared just prior to use.
ISO 8299:2019(E)
5.2.1 Nitric acid solutions, c(HNO ) = 0,3 mol/l, 1 mol/l, 3 mol/l, 4 mol/l, 7 mol/l and other.
5.2.2 Ferrous sulfate, c(FeSO ) = 0,2 mol/l, in amidosulfuric acid, c(NH SO H) = 0,2 mol/l, and sulfuric
4 2 3
acid, c(H SO ) = 1 mol/l, freshly prepared.
2 4
5.2.3 Sodium nitrite, c(NaNO ) = 0,7 mol/l, freshly prepared.
5.2.4 Hydrogen peroxide solution, c(H O ) = 10 mol /l.
2 2
5.2.5 Silver nitrate, c(AgNO ) = 0,01 mol/l or, suitable for precipitation method.
5.2.6 Ascorbic acid, c(C H O ) = 0,1 mol/l in nitric acid 0,1 mol/l.
6 8 6
5.2.7 Hydrofluoric acid, c(HF) = 0,001 mol/l, 0,05 mol/l or 27 mol/l. HF can mix with nitric acid
solution before use.
5.2.8 Sodium hydroxide, c (NaOH) = 1 mol/l.
5.2.9 Ammonium sulfate, c((NH ) SO ) = 0,5 mol/l.
4 2 4
5.3 Resin, applicable for separation/purification of Pu and U
5.3.1 General
Complete recovery (100 % separation) of plutonium or uranium is not required to perform IDMS. For
mixed oxide samples, alpha spectrometry correction for Pu isotopic composition is recommended.
The following resins, or other materials and preparation procedures that obtain equivalent performance
can also be applied.
5.3.2 Preparation of resin
1)
5.3.2.1 Anion exchange resin
Resin in HCl condition should be reconditioned to nitric acid condition by one of the following
procedures, or another which can lead to a separation of similar quality, and stored in distilled water.
a) Twice with the equivalent resin bed volumes of distilled water;
twice with the equivalent resin bed volumes of 0,3 mol/l nitric acid (5.2.1);
twice with the equivalent resin bed volumes of 4 mol/l nitric acid (5.2.1);
with the equivalent resin bed volumes of 7 mol/l to 8 mol/l nitric acid (5.2.1) until a sample of the
supernatant solution no longer yields a chloride precipitate after addition of silver nitrate (5.2.5) or
confirm by Cl test paper.
b) With 20 times the resin bed volumes of 1 mol/l sodium hydroxide (5.2.8) and then wash by
distilled water;
2 times the resin bed volumes of 0,5 mol/l ammonium sulfate (5.2.9) and then wash by distilled water;
10 times the resin bed volumes of 1,3 mol/l nitric acid (5.2.1) and then wash by distilled water;
1) Anion exchange resins AG1 or AG2 are examples of suitable products supplied by Bio-rad. This information is
given for the convenience of users of this document and does not constitute an endorsement by ISO of the products
named. Equivalent products may be used if they can be shown to lead to the same results.
4 © ISO 2019 – All rights reserved
ISO 8299:2019(E)
3 times the resin bed volumes of 1 mol/l sodium hydroxide (5.2.8) and then wash by distilled water;
3 times the resin bed volumes of 1,3 mol/l nitric acid (5.2.1) and then wash by distilled water;
3 times the resin bed volumes of 1 mol/l sodium hydroxide (5.2.8) and then wash by distilled water;
3 times the resin bed volumes of 1,3 mol/l nitric acid (5.2.1) and then wash by distilled water.
c) Twice with the equivalent resin bed volumes of distilled water;
twice with the equivalent resin bed volumes of 1 mol/l sodium hydroxide (5.2.8);
with the equivalent resin bed volumes of distilled water;
with the equivalent resin bed volumes of 3 mol/l nitric acid (5.2.1) until a sample of the supernatant
solution no longer yields a chloride precipitate after addition of silver nitrate (5.2.5) or confirm by
Cl test paper.
2)
5.3.2.2 Extraction separation resins
a) Conditioning: just before use, add approximate 3 mol/l nitric acid (5.2.1) for 3 to 4 times the resin
volume to condition the resin into nitrate form. Other nitric acid concentration can be applied when
enough efficiency is confirmed.
b) Storage: resins should be stored in a capped conical beaker and used within few days after
conditioning. If rinsed with water after the above conditioning, it can be stored for a month.
WARNING — Resin should be rinsed with water after use for the separation, or after adjustment
to nitric condition but unused. Storage of the resin for more than a few days in nitric acid can
lead to explosive decomposition.
6 Apparatus
6.1 Shielded cells equipped with manipulators or tongs, for carrying out remotely the chemical
preparations on highly radioactive solutions.
6.2 Glove boxes, for handling diluted spent fuel solutions or small plutonium samples free from fission
products.
6.3 Analytical balance, with ± 0,1 mg uncertainty, installed in a shielded cell or a glove box.
6.4 Pipet and stand, with disposable pipette tips, installed in a shielded cell or a glove box.
6.5 Hot plate, in a glove box to fume diluted solutions or dissolving the spikes. Parallel use with vapour
condensing system is recommended.
6.6 Disposable chromatographic columns, with approximate dimensions of 4 mm inner diameter,
45 mm height and a 10 ml capacity upper funnel. Columns of different dimensions may be used provided
that the volumes of eluents are properly adapted.
6.7 Common laboratory ware, consisting of disposable plastic pipettes and containers, flasks,
beakers and vials.
2) TEVA from Eichrom or Tristen are examples of suitable products available commercially. This information is
given for the convenience of users of this document and does not constitute an endorsement by ISO of the products
named. Equivalent products may be used if they can be shown to lead to the same results.
ISO 8299:2019(E)
7 Apparatus for mass spectrometry
7.1 Mass spectrometers, designed for precise measurements of isotopic compositions having at least
the following features.
7.1.1 General specifications
— Mass range: 10 amu to 280 amu.
— Resolution: > 380 % at 5 % of the peak height; this resolution should be meas-
235 238
ured at the U and U masses.
−4
— Peak top flatness: Less than 10 relative change (300 ppm by mass) in the signal for
a change of ± 0,025 mass units with a Faraday cup detector; less
−3
than 10 relative change with an electron multiplier detector.
−6
— Abundance sensitivity: < 5 × 10 at mass 237 relative to mass 238.
— Sensitivity and transmission: > 1 ion collected for 5 000 uranium atoms on the sample filament.
7.1.2 Thermal ionization source, consisting of a magazine (also called a turret) loaded with single,
double or triple filament assemblies and covering shields. A stack of extraction lenses used to accelerate
and focus the ion beam into the mass analyser.
−5
7.1.3 Vacuum, with a capability of preferably less than 5 × 10 Pa in the ion source chamber and less
−6
than 5 × 10 Pa in the analyser. Specifications depend on the instrument.
7.1.4 Detector system, consisting of a Faraday multi-detector assembly with a minimum of six
233 234 235 236 238 238 239 240 241 242 244
detectors that can analyse the U, U, U, U, U and the Pu, Pu, Pu, Pu, Pu, Pu.
It is also recommended that the instrument be equipped with either a secondary electron multiplier or
Daly detector. This detector can be used during automatic measurements with the TE method to focus the
ion beams, and also for special cases where the sample is too small for normal analysis using the Faraday
detectors. The detector is also important for making background measurements on filament blanks.
7.2 Filament preheating and degassing device, is recommended for cleaning filaments prior to
loading sample if specifics are needed.
7.3 Filament preparation device, for loading the samples onto filaments and the reproducible drying
and oxidation of the samples without cross-contamination.
8 Sample preparation
8.1 Subsampling and spiking
Spikes isotope composition should differ significantly from the samples in order to obtain enough
isotope dilution effect for accurate IDMS measurement. The spike should be selected based on previous
[7]
evaluation of suitable mixing ratio . Other conditioning steps, acid concentrations and heating
temperatures should also be optimized depending on the sample types. Examples of subsampling and
spiking procedures are listed below.
Take the precautions needed to avoid evaporation of the sample solution during weighing and storage.
NOTE A longer dissolution time can be necessary if the spike contains some binding material(s) other than
nitric acid.
6 © ISO 2019 – All rights reserved
ISO 8299:2019(E)
8.1.1 Pellet or powder samples
a) If the sample is a pellet, crush before subsampling. Weigh to ± 0,1 mg in a tared flask or vial. Record
the mass, m , of the sample.
b) Dissolve with 3 mol/l to 8 mol/l nitric acid (5.2.1). Add few drops of hydrofluoric acid (5.2.7) or
dissolve with previously mixed nitric acid and hydrofluoric acid solution for Pu rich samples. Heat
at approximately 100 °C on a hotplate.
c) Cool to room temperature and visually inspect if dissolution is complete. If undissolved sample
remains, add 1 or 2 more drops of hydrofluoric acid (5.2.7) and heat. Dilute if necessary based on
previous evaluation. Weigh and record the mass, m , to ± 0,1 mg.
d) Aliquot the sample solution to another tared bottle or vial, weighed to ± 0,1 mg, and record the
mass, m′ .
e) Add nitric acid to dilute if necessary. Measure and record the mass m′ of the solution and mix well.
Calculate the dilution factor, F, in accordance with Formula (1):
′
mm⋅
F = (1)
′
mm⋅
f) Pipette the diluted sample, containing 0,1 mg to 0,3 mg of uranium and/or plutonium solution into
a beaker or vial and use this aliquot to determine the isotopic composition of the uranium and/or
plutonium.
g) Aliquot and weigh the spike and the above diluted sample solution to ± 0,1 mg in a tared beaker or
flask. Record the masses, m and m , of the aliquots of the spike and the diluted sample solutions,
S C
respectively. Other spiking procedures are also applicable depending on spike type. One example is
as follows.
If using dried spike, element amount, in the spike vial, m is known. Tare the spike vial, then add the
S
above diluted sample solution based on previous evaluation and weigh m to ± 0,1 mg. Heat if necessary
C
to dissolve dried spike. Complete transfer into cleaned and tared vial is recommended to recover all
spike material. Use this mixture for the determination of the uranium and/or plutonium concentrations.
8.1.2 Concentrated nuclear fuel solution samples (such as reprocessing solution)
a) Weigh 1 ml to 2 ml of the concentrated nuclear fuel solution to ± 0,1 mg in a vial containing a LSD
spike (5.1.6). Add 7 ml of 3 mol/l nitric acid (5.2.1). Record the mass of the sample aliquot and the
mass of the spike solution introduced into the vial and dried to prepare the LSD spike.
b) Heat at 95 °C ± 5 °C to re-dissolve the dried spike quantitatively.
c) Let the solution of spiked sample cool to room temperature, mix well, pipette an aliquot of 0,2 ml to
0,5 ml and transfer it into another vial. Use this aliquot to determine the uranium and/or plutonium
concentrations.
d) Pipette another sample, containing 0,2 to 0,3 mgPu of concentrated nuclear fuel solution into an
empty vial, Use this aliquot for the determination of the isotopic compositions of uranium and/or
plutonium.
8.1.3 Plutonium nitrate solution samples (such as product solution from a reprocessing plant)
a) Weigh at least 1 ml of the sample solution into a tared flask or vial. Record the mass of the sample
to ± 0,1 mg.
b) Dilute if necessary and weigh and record its mass to ± 0,1 mg.
c) Aliquot sample solution into a vial containing a LSD spike (5.1.6) based on previous evaluation and
weigh to ± 0,1 mg.
ISO 8299:2019(E)
d) Dissolve the dried spike completely with 7 ml of 3 mol/l nitric acid (5.2.1) and heat at 95 °C ± 5 °C
on a hotplate.
e) Cool to room temperature and visually inspect that dissolution is complete. Pipette an aliquot of
0,1 mg to 0,3 mg of plutonium into a beaker or vial. Use this aliquot to determine the plutonium
concentration.
f) Pipette the diluted sample [8.1.3 b)], containing 0,1 mg to 0,3 mg of plutonium solution, into a
beaker or vial and use this aliquot to determine the isotopic composition of the plutonium.
8.1.4 Dried nitrate samples
a) Dissolve the dried nitrate sample with 7 mol/l to 8 mol/l nitric acid (5.2.1), and heat at approximately
100 °C on a hotplate. Cool to room temperature and visually inspect to ensure that dissolution is
complete.
b) Dilute if necessary, transfer completely into a cleaned and tared vial and weigh. Record the mass
to ± 0,1 mg.
c) Follow same procedure from [8.1.1 d)] to [8.1.1 g)].
8.2 Chemical valency adjustment
If there is a risk of a Pu(IV) polymer being present in the sample or in the spike, it is advisable to add
3+
hydrofluoric acid (5.2.7) and reflux the sample aliquot, and to complex the excess fluoride with Al
before proceeding. If hydrofluoric acid (5.2.7) is used for dissolving the sample, it can be removed by
drying the sample.
For samples that contain both plutonium and uranium, or plutonium containing Am from ingrowth,
separation/purification is required using one of the column purification options in 8.3. Valence
adjustment should be performed before column purification to ensure that all plutonium isotopes are
in the tetravalent state. One of the following procedures can be applied.
8.2.1 Valence adjustment with ferrous solution
a) Add 0,1 ml of ferrous solution (5.2.2) to each sample aliquot.
b) Mix and wait 15 min for complete reduction of plutonium to Pu(III) or Pu(IV).
c) Add 0,1 ml of sodium nitrite solution (5.2.3) and mix for 10 min to re-oxidize all plutonium to the
tetravalent state.
Other condition is also applicable if same result can be obtained.
8.2.2 Valence adjustment with hydrogen peroxide
a) Add approximately 0,5 ml of 7 mol/l to 8 mol/l nitric acid (5.2.1) if the samples are dried and heat
at 100 °C to dissolve.
b) Add 0,2 ml to 0,4 ml of hydrogen peroxide (5.2.4), cover with watch glass, mix and wait 15 min for a
complete reduction of all plutonium to Pu(III) or Pu(IV).
c) Heat at 80 °C ± 5 °C for 90 min or
...
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