SIST EN ISO 8690:2026

SLOVENSKI STANDARD
01-oktober-2026
Merjenje radioaktivnosti - Radionuklidi, ki oddajajo gama žarke in beta delce -
Preskusna metoda za oceno enostavnosti dekontaminacije površinskih materialov
(ISO 8690:2024)
Measurement of radioactivity - Gamma ray and beta emitting radionuclides - Test
method to assess the ease of decontamination of surface materials (ISO 8690:2024)
Messung der Radioaktivität - Gamma- und Beta-Strahlung emittierende Radionuklide -
Prüfverfahren zur Bewertung der Dekontaminierbarkeit von Werkstoffoberflächen (ISO
8690:2024)
Mesurage de la radioactivité - Radionucléides émetteurs gamma et bêta - Méthode
d'essai pour évaluer l'aptitude à la décontamination des matériaux de surface (ISO
8690:2024)
Ta slovenski standard je istoveten z: EN ISO 8690:2026
ICS:
13.280 Varstvo pred sevanjem Radiation protection
17.040.20 Lastnosti površin Properties of surfaces
27.120.20 Jedrske elektrarne. Varnost Nuclear power plants. Safety
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 8690
EUROPEAN STANDARD
NORME EUROPÉENNE
August 2026
EUROPÄISCHE NORM
ICS 13.280
English Version
Measurement of radioactivity - Gamma ray and beta
emitting radionuclides - Test method to assess the ease of
decontamination of surface materials (ISO 8690:2024)
Mesurage de la radioactivité - Radionucléides Messung der Radioaktivität - Gamma- und Beta-
émetteurs gamma et bêta - Méthode d'essai pour Strahlung emittierende Radionuklide - Prüfverfahren
évaluer l'aptitude à la décontamination des matériaux zur Bewertung der Dekontaminierbarkeit von
de surface (ISO 8690:2024) Werkstoffoberflächen (ISO 8690:2024)
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 8690:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO 8690:2024 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 8690:2026 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 8690:2024 has been approved by CEN as EN ISO 8690:2026 without any modification.

International
Standard
ISO 8690
Third edition
Measurement of radioactivity —
2024-09
Gamma ray and beta emitting
radionuclides — Test method to
assess the ease of decontamination
of surface materials
Mesurage de la radioactivité — Radionucléides émetteurs
gamma et bêta — Méthode d'essai pour évaluer l'aptitude à la
décontamination des matériaux de surface
Reference number
ISO 8690:2024(en) © ISO 2024
ISO 8690:2024(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: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 8690:2024(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols . 2
3.1 Terms and definitions .2
3.2 Symbols .3
4 Principle . 4
5 Apparatus . 4
5.1 Beakers .4
5.2 Radiation detector . . .4
5.3 Pipettes .5
5.4 Two polytetrafluoroethylene (PTFE) or quartz ampoules .5
5.5 Storage bottles .5
5.6 Mounting .5
5.7 Cage-stirrer apparatus .6
6 Contamination and decontamination agents . 6
6.1 Contaminant solutions .6
6.1.1 Composition of contaminant solutions .6
6.1.2 Preparation of the contaminant solutions.6
6.1.3 Preparation of contaminant solution using neutron activation .7
6.1.4 Storage of the contaminant solution .7
6.2 Decontaminant solution .8
7 Test specimens . 8
7.1 Preparation and preliminary testing .8
7.1.1 Resistance to cleaning solution .8
7.1.2 Test specimens of non-metallic materials .8
7.1.3 Test specimens of metallic materials .8
7.2 Number and dimensions .9
7.3 Conditioning and cleaning .9
8 Procedure . 9
8.1 Determining the specific pulse rate of each contaminant solution .9
8.2 Contamination .10
8.3 Decontamination . 12
8.4 Determining the residual pulse rate . 13
9 Calculation of results and assessment of ease of decontamination . 14
10 Test report . 14
Annex A (informative) Holder for contamination of test specimen .16
Annex B (normative) Cage-stirrer apparatus for decontamination .18
137 60
Annex C (informative) Formulae for preparation of the Cs and Co contaminant solutions .27
Annex D (informative) Calculations for the production of the contaminant solution using
neutron activation .30
Annex E (informative) Example of a test report .32
Bibliography .34

iii
ISO 8690:2024(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 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).
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 2, Radiological protection.
This third edition cancels and replaces the second edition (ISO 8690:2020), of which it constitutes a minor
revision.
The main changes are as follows:
— symbols were corrected and clarified;
— principles were rephrased and optimized;
— Table 1 was optimized;
— figures were completed and corrected;
— editorial corrections were made.
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
ISO 8690:2024(en)
Introduction
Wherever radioactivity is used, there is a risk that surfaces can become contaminated through contact
with radioactivity in solution or airborne radioactivity. It is normally necessary to remove this surface
contamination to reduce the risk to staff from accidental ingestion of the radioactivity on the surface. The
ease of decontaminating surface materials is therefore an important parameter to consider when selecting
materials to use, e.g. for facilities in the nuclear industry, in radionuclide laboratories or nuclear medicine
facilities.
This document defines a quantitative method under objective conditions for testing the ease of
decontamination of surface materials. The method enables the comparison of different surface materials to
support decisions on materials to use for different applications.
For the test, radioactive solutions are deposited onto a sample of the material being studied. The solutions
60 137 134
contain radionuclides commonly found in the nuclear industry ( Co, Cs or Cs) and are in aqueous
form. The surface is then cleaned and the residual activity on the surface is measured to give a quantitative
measure of the ease of decontamination.
The results of the tests on different materials therefore help the user select the best surface material for the
application being considered.
v
International Standard ISO 8690:2024(en)
Measurement of radioactivity — Gamma ray and beta
emitting radionuclides — Test method to assess the ease of
decontamination of surface materials
1 Scope
This document applies to the testing of surfaces that may become contaminated by radioactive materials.
The ease of decontamination is a property of a surface and an important criterion for selecting surface
materials used in the nuclear industry, interim storage or disposal facilities from which contamination can
be removed easily and rapidly without damaging the surface. The test described in this document is a rapid
laboratory-based method to compare the ease of decontamination of different surface materials.
The results from the test can be one parameter to take into account when selecting surface coatings such
as varnish or impervious layers such as ceramics and other surfaces. The radionuclides used in this test
137 134 60
are those commonly found in the nuclear industry ( Cs, Cs and Co) in aqueous form. The test can
also be adopted for use with other radionuclides and other chemical forms, depending on the customer
requirements, if the solutions are chemically stable and do not corrode the test specimen.
The test does not measure the ease of decontamination of the surface materials in practical use, as this
depends on the radionuclide(s) present, their chemical form, the duration of exposure to the contaminant
and the environmental conditions amongst other factors.
The test method is not intended to describe general decontamination procedures or to assess the efficiency
of decontamination procedures (see ISO 7503-1 to ISO 7503-3).
The test method is not suitable for use of radiochemicals if the radionuclide emits low energy gamma rays or
beta particles that are readily attenuated in the surface.
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 15, Rolling bearings — Radial bearings — Boundary dimensions, general plan
ISO 273, Fasteners — Clearance holes for bolts and screws
ISO 2009, Slotted countersunk flat head screws — Product grade A
ISO 2010, Slotted raised countersunk head screws — Product grade A
ISO 3819, Laboratory glassware — Beakers
ISO 4762, Hexagon socket head cap screws
ISO 11074, Soil quality — Vocabulary
ISO 80000-10, Quantities and units — Part 10: Atomic and nuclear physics
ISO/IEC Guide 98-3, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
measurement (GUM: 1995)
ISO/IEC Guide 99, International vocabulary of metrology — Basic and general concepts and associated terms (VIM)

ISO 8690:2024(en)
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11074, ISO 80000-10,
ISO/IEC Guide 98-3 and ISO/IEC Guide 99 and the following 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/
3.1.1
surface contamination
radioactive substances deposited on defined surfaces
[SOURCE: ISO 7503-1:2016, 3.1.2]
3.1.2
decontamination
complete or partial removal of radioactive contamination by a deliberate physical, chemical, or biological process
Note 1 to entry: It is preferred that decontamination does not significantly change the characteristics of the surface.
[8]
[SOURCE: IAEA. IAEA Safety glossary ]
3.1.3
specific pulse rate
I
s
pulse rate caused in the measuring apparatus under given geometrical conditions by 1 ml of a contaminant
solution
Note 1 to entry: It is expressed in pulses per minute standardized on 1 ml of the contaminant solution. Pulse rates are
derived from count rates applying dead time and background corrections.
3.1.4
residual pulse rate
I
r
pulse rate caused in the measuring apparatus under given geometrical conditions by the residual
radionuclide on the tested side of the specimen after decontamination (3.1.2)
Note 1 to entry: It is expressed in pulses per minute.
3.1.5
mean residual pulse rate
I
r
arithmetic mean of the residual pulse rate values obtained for the five test specimens contaminated by the
same radionuclide
Note 1 to entry: It is expressed in pulses per minute.
3.1.6
standardized mean residual pulse rate
I
rn,
corrected value of the mean residual pulse rate (3.1.5)
Note 1 to entry: The correction factor is obtained by dividing a reference value of the specific pulse rate by the pulse
rate of a contaminant solution used in the test.
Note 2 to entry: It is expressed in pulses per minute.

ISO 8690:2024(en)
Note 3 to entry: The purpose of the correction factor is to compensate for variations in specific pulse rates of
contaminant solutions used in different test laboratories.
3.1.7
final residual pulse rate
60 134 137
arithmetic mean of the standardized mean residual pulse rate I (3.1.6) obtained for Co and Cs or Cs
rn,
Note 1 to entry: It is expressed in pulses per minute.
3.2 Symbols
For the purposes of this document, the following symbols apply.
A Activity of the radionuclide (Bq)
−1
A Specific activity of the radionuclide (Bq·g )
S
A Activity of the radionuclide in the contaminant solution
E
D Distance between the centre point of the contaminated area and the edge of the sensitive detector
min
cross-section (mm)
h Distance of the contaminated test surface from the detector surface (mm)
I Total pulse rate (counts (pulses) per min or cpm)
E
I Residual pulse rate (counts (pulses) per min or cpm)
r
I Standardized residual pulse rate (counts (pulses) per min or cpm)
r,n
I Specific pulse rate (counts (pulses) per min or cpm)
s
r Final volume of contaminant (radionuclide stock) solution (ml)
−1
s Activity concentration of stock solution (from manufacturer's data) (MBq·ml )
−1
q Carrier concentration (mol·l )
V Volume (l)
m Mass (g)
−1
M Molar mass (kg·mol )
H Abundance
−2
σ Cross section (cm )
-2 −1
Φ Neutron flux (cm ·s )
N Avogadro constant
L
−1
τ Carrier concentration of the radionuclide-initial solution (mol·l )
t Time (s)
t Half-life (years)
1/2
T Added amount of carrier unit (mol)
E
T Required amount of carrier unit (mol)
S
ISO 8690:2024(en)
T Amount of the carrier in the case of decay rate characterization (mol)
Z
−1
u Carrier concentration of the applied carrier solution (mol·l )
−1
τ Initial radionuclide solution (mol·l )
V Required volume of the carrier solution (l)
T
4 Principle
60 137 134
A specimen of the material is contaminated using a solution containing Co and Cs or Cs (carrier
−5 −1
concentration: 10 mol·l ; pH value: 4). 100 μl samples of these solutions on the specimen surface are
counted using a large area radiation detector. The specific pulse rates of contaminant solutions are calculated
using the results from the count.
Contamination of test material specimens was achieved by treating a defined area with the contaminant
solutions. Subsequent decontamination was achieved with demineralized water. The residual pulse rate I is
r
determined by measuring the contaminated samples.
The standardized mean residual pulse rates I for each radionuclide are calculated. The arithmetic mean
rn,
60 137 134
of the respective values for Co and Cs or Cs (final residual pulse rate) is used to assess the ease of
decontamination by mean of a classification that has been empirically compiled.
5 Apparatus
In addition to ordinary laboratory apparatus, the following equipment is required for testing the ease of
decontamination of surfaces.
5.1 Beakers
Two beakers, of the low-form type, having a capacity of 2 000 ml and in accordance with requirements given
in ISO 3819.
5.2 Radiation detector
A detector and associated electronics are required for determining the pulse rate. Suitable detectors include
gas-filled proportional counter, scintillation and semi-conductor types.
The minimum size of the sensitive area of the detector shall be a circle having a 30 mm diameter, but in
practice, the geometrical requirement specified normally necessitates the use of a larger sensitive area.
D −12,m5 m
min
To comply with geometrical requirements, the ratio shall not be less than 3,
h
where
D is the smallest distance, in millimetres, from the centre point of the contaminated area, as projected
min
onto the detector cross-section, to the edge of the sensitive detection area;
h is the distance, in millimetres, of the contaminated test surface from the detector surface (see Figure 1).
D −12,m5 m
min
If the geometrical requirement ≥3 is not met, a detector having a circular sensitive area not
h
less than 30 mm in diameter may be used, provided that
a) for the determination of the specific pulse rate (see 8.1), the 100 µl of contaminant solution is evenly
distributed as a series of individual droplets over a circular area 25 mm in diameter, i.e. the area over
which the test specimens are contaminated;

ISO 8690:2024(en)
b) the net pulse rate of 100 µl of contaminant solution measured under these geometrical conditions is not
less than 200 000 pulses per minute (see 8.1).
CAUTION — For the apparatus described in 5.3 to 5.6, separate equipment shall be used for the two
or three radionuclides to prevent cross-contamination.
Key
1 detector
2 test specimen
3 contamination
Figure 1 — Geometrical requirements (cross-section)
5.3 Pipettes
Two pipettes with disposable tips, having a capacity of 100 µl.
Two pipettes with disposable tips, having a capacity of 1 000 µl.
5.4 Two polytetrafluoroethylene (PTFE) or quartz ampoules
Two polytetrafluoroethylene (PTFE) ampoules for preparation of the contamination solution
or
two quartz ampoules for the activation of the inactive stock solution in the neutron reactor are required.
5.5 Storage bottles
Two polytetrafluoroethylene (PTFE) bottles for storage of the radioactive stock solution are required.
NOTE Other fluorinated materials of similar chemical resistance are possible alternatives to
polytetrafluoroethylene (PTFE), such as polytetrafluoroethylene/perfluoropropylene (PTFE/PFP), perfluoro alkoxyl
alkane (PFA) and poly(vinylidene fluoride) (PVDF).
5.6 Mounting
Ten holders for test specimens (5 for each radionuclide), made of poly(methyl methacrylate) (PMMA), serving
as positioning aids for the contamination step (see Annex A).
Each holder shall contain a flat silicone rubber ring (45 mm × 25 mm × 2 mm) made of unfilled material
having a Shore A hardness value of not more than 60.
NOTE 1 Unfilled, unpigmented, fluorinated silicone rubber has been found particularly suitable for this purpose.

ISO 8690:2024(en)
Before using for the first time, the rubber rings shall be cleaned using the organic solvent mixture (see 7.3)
used for cleaning the test specimens. The rings should only be reused after careful decontamination.
NOTE 2 10 holders, five for each radionuclide, reduce the time needed to carry out the test and help to prevent
cross-contamination.
5.7 Cage-stirrer apparatus
A cage-stirrer apparatus for six test specimens shall be used in accordance with Annex B. The apparatus
shall be equipped with a motor allowing the stirrer to be rotated at 100 r/min.
6 Contamination and decontamination agents
6.1 Contaminant solutions
6.1.1 Composition of contaminant solutions
60 137 134
The test specimens shall be contaminated by the radionuclides Co and Cs or Cs, contained in separate
solutions.
The use of other radionuclides in aqueous solutions, which may be more suitable in terms of type and
chemical behaviour for the envisaged purpose of the surface material, can be adopted, subject to consultation
with the testing laboratory.
However, the contaminant solutions shall be chemically stable and shall not corrode the test specimens. The
decontaminated samples shall be stable in order to allow the residual contamination to be measured. Special
measurement techniques may be required in the case of radionuclides where the emissions are subject to
absorption.
The activity concentration of the contaminant solution shall be such that an evaporated 100 µl sample
produces a pulse rate of not less than 200 000 pulses per minute in the detector, after correction for dead
time and background.
NOTE An activity concentration of 0,2 MBq/ml is usually sufficient to fulfil the requirement.
−5 −1
The radionuclides shall be used with a carrier concentration of (1 ± 0,1) · 10 mol·l in a solution of nitric
acid with a pH-value of (4,0 ± 0,2). To make sure that the activity concentration does not change, the pH-value
of the contaminant solution is checked monthly or before use. This shall be done using a sample of each
contaminant solution.
6.1.2 Preparation of the contaminant solutions
2+ +
6.1.2.1 Apart from Co and Cs ions and the corresponding nitrate ions, the radionuclide stock solutions
shall not contain constituents that remain in the residue when the solutions are evaporated as described in
6.1.2.6.
All reagents used shall be of analytical grade (pro analysis) or better.
134 137 60
6.1.2.2 With the help of the data available for the activity concentrations of the Cs or Cs and Co stock
solutions, the quantities of these solutions to be used for preparing the desired quantities of contaminant
solutions can be calculated. Formulae for the preparation of the contaminant solutions are given in Annex C.
6.1.2.3 The next step is to calculate from these input quantities the carrier quantities transferred with
the radionuclides, and from these in turn calculate the quantities of cobalt(II) nitrate [Co(NO ) ] or caesium
3 2
nitrate (CsNO ) solutions respectively, which need to be added to establish a carrier concentration of
−5 −1
(1 ± 0,1) · 10 mol·l in the individual solutions.

ISO 8690:2024(en)
6.1.2.4 Place these quantities of carrier solutions in polytetrafluoroethylene vessels of sufficient size to
allow dilution of the solutions to their final volumes. In order to enhance the displacement of chloride ions
which may be present in the radionuclide stock solutions, add 5 ml of nitric acid solution (high purity grade)
−1
[HNO = 1 mol·l ] per 90 ml of final volume of contaminant solution.
60 134 137
6.1.2.5 Finally, add the calculated quantities of Co, Cs or Cs stock solutions to the carrier solution.
6.1.2.6 Evaporate the mixtures to dryness using infrared lamps until fume evolution stops.
6.1.2.7 Then heat the vessels for another 2 h with the infrared lamps being moved to double the initial
distance.
6.1.2.8 After cooling, top the vessels up to the respective final volume by adding nitric acid with a
pH-value of 4.
−1
NOTE Nitric acid with a pH value 4 is produced by diluting 7 µl of nitric acid (ρ = 1,4 g∙ml ) to 1 l water using
double distilled water.
6.1.2.9 Check the specific pulse rates of the thoroughly homogenized solutions in accordance with 8.1 and
the pH value.
6.1.3 Preparation of contaminant solution using neutron activation
Stable Co(NO ) or CsNO solutions are used as stock solutions.
3 2 3
Chloride solutions are inappropriate, because the activation of chlorine produces unwanted radionuclides
35 36 38
such as S, Cl and Cl.
60 134
The specific activity of the Co- and Cs-solution produced by neutron activation can be
calculated from concentration of the Co- and Cs-stock solutions. The ideal carrier concentration should be
−5 −1
1,0 · 10 mol·l .
By means of concentration of the inactive Co- and Cs-stock solutions the amount of these solutions can
be calculated, which are required for the desired volumes of the contaminant solutions with the carrier
-5 −1
concentration of 1,0 · 10 mol·l .
Co- and Cs-stock solutions are loaded in a polytetrafluoroethylene (PTFE) or quartz ampoule and dried by
maximum 40 °C. Subsequently the ampules are sealed and activated in the reactor.
The irradiation time can be calculated using the formulae in Annex D. The irradiation time depends on the
radionuclide, the neutron flux, and the starting stock solution concentration.
After activation the ampoules are unsealed and the activated material are transferred to sealable bottles
for storage using nitric acid (pH = 4) solution. Continue rinsing until the desired volume of stock solution is
achieved.
For opening ampoules following operation, it is recommended that the ampoule is positioned in the centre of a
closable polyethylene tube (PE) and broken carefully in a vice. To be sure that all the activated contents were
transferred, the complete content of the tube is washed over with nitric acid (pH = 4) into the storage bottle.
6.1.4 Storage of the contaminant solution
In order to avoid wall effects which may alter the concentration, the individual solutions shall be kept in well-
sealed polytetrafluoroethylene containers, which, in turn, are enclosed in glass containers of the smallest
possible size to reduce the risk of evaporation.
A solution prepared in accordance with this procedure can be used as long as its pH-value lies within the
specified range and the activity concentration has not changed by more than 5 % compared to its initial
value (decay corrections being applied).

ISO 8690:2024(en)
6.2 Decontaminant solution
Decontaminant solutions used for examinations should be demineralized water with a maximum electrolytic
−1
conductivity of 3 µS∙cm .
7 Test specimens
7.1 Preparation and preliminary testing
7.1.1 Resistance to cleaning solution
For the purposes of the preliminary testing, a test specimen having at least one flat surface of adequate size
(see 7.3) and which can consist of any suitable material — such as non-metallic or metallic materials, coating
systems, floor coverings — shall be used. The test specimens shall have sufficient resistance to the cleaning
solution (e.g. alkaline detergents). This shall be checked using the following procedure:
a) soak a small piece of cotton wool in the cleaning liquid, place it on the surface of a specimen and cover
with a Petri dish;
b) after 10 min contact, remove the cotton wool and rinse the specimen using demineralized water;
c) then dry the specimen for 1 h at (40 ± 5) °C;
d) examine the specimen visually.
Specimens which show more than a slight change in colour and lustre are unsuitable for testing.
7.1.2 Test specimens of non-metallic materials
The non-metallic test materials— such as high polymers, glass, ceramic materials — shall have the same
surfaces and the same quality as like in actual usage.
If the backing of the test specimen is porous or is an uncoated metal, the back and edges shall be coated in a
readily decontaminable material (e.g. by using an epoxy, polyurethane or chlorinated rubber coating).
For preparing test specimens with coatings, a representative sample shall be taken from the coating material
to be investigated and prepared for testing in accordance with the relevant standard methods.
The coating materials shall be applied to the carriers or the backings in the manner customary in actual
usage and shall be suitably post-treated; any additional treatment, such as additional thermal ageing, is not
permissible.
NOTE It is recommended to avoid electrostatic interaction between the solution and the material, e.g. by
discharging the material.
The date of preparation of the test specimens shall be recorded.
7.1.3 Test specimens of metallic materials
Test specimens of metal or with metallic surfaces shall be pretreated in a manner typical of actual usage.
For coating of the reverse and edges, the back and edges of the specimen shall be treated as for non-metallic
material (7.1.2).
The surface roughness (average roughness value) shall be stated by the manufacturer and shall be mentioned
in the description of the sample material.

ISO 8690:2024(en)
7.2 Number and dimensions
For the purposes of the test, 25 nominally identical test specimens shall be prepared and of these at least
two groups of five shall be tested in two parallel tests.
NOTE 1 Remaining test specimens are used for the preliminary tests in accordance with 7.1 and as reference
specimens following the test.
The test specimens should measure 50 mm × 50 mm (with a tolerance of −2 mm and +10 mm for each side).
The thickness of the test specimen should be between 1 mm and 10 mm. One corner shall be marked as the
reference corner by means of a cross of fine scratches on the back of each test specimen.
Other test specimen dimensions and other conditions for preparation are subject to arrangement and shall
be stated in the test report.
NOTE 2 Test specimens of dimensions not greater than 51 mm × 51 mm × 3,5 mm can be stored and transported
conveniently using slide storage containers; this helps to avoid contact between the surfaces to be tested.
7.3 Conditioning and cleaning
The test specimens shall be kept in open containers at the testing laboratory in a clean and non-corrosive
atmosphere at (23 ± 2) °C (see ISO 291) for not less than 14 days. This requirement does not apply to test
specimens with ceramic or glass surfaces.
To clean the surface, wipe the test specimens using a soft cellulose tissue. First wipe the surface to be tested
using a tissue heavily soaked in the cleaning mixture, which should be composed of benzine (boiling range
from 60 °C to 80 °C) and isopropanol (minimum content 99 %) in a mixing ratio of 1:1 by volume. Repeat the
wiping using an "almost dry" tissue. Repeat the wiping operation a third time using a tissue heavily soaked
in pure water.
In each case, carry out the wiping operation five times in a single direction over the sample using a different
portion of the tissue for each stroke. The tissue shall only be used for one wiping operation (i.e. five strokes).
Finally, rinse the test specimens with pure water using a squeeze bottle to remove all fibres and particles
from the surface to be tested. Dry the test specimens in a vertical position (in an environment free of
airborne contaminants) for 1 h at (40 ± 5) °C.
Test specimens coated with organic surface materials can, in addition, be tested without any prior cleaning
when subject to special requirements. In such cases, the preparation of the test specimens shall be carried
out in accordance with the manufacturer's instructions. If the cleaning stage is omitted, this shall be noted
in the test report.
8 Procedure
8.1 Determining the specific pulse rate of each contaminant solution
Dispense a 100 µl aliquot of the contaminant solution on the centre of each of three sheets of window
glass, measuring 50 mm × 50 mm, in accordance with the procedure laid down in 8.2. The positioning
aid (see 5.6) or a similar device may be used. Evaporate the drops to dryness under infrared lamps at a
maximum temperature of 45 °C. Place the detector (as specified in 5.2) in the same measurement geometry
(particularly with the regard to the distance of the contaminated glass surface from the detector) that is to
be used for the test specimens (see 8.3). Measure the pulse rate on the three glass sheets.
It is to be ensured that the measurement geometry (particularly with regard to the distance of the
contaminated glass surface from the detector) is the same as it was planned for the measurement on the test
specimens (see 8.3).
The measuring period shall be 1 min for each sheet. Apply corrections for background and dead time losses.

ISO 8690:2024(en)
Multiply the arithmetic mean of the three results by a factor of 10 so that the result is expressed in terms of
pul
...