ISO 9696:2007
(Main)Water quality — Measurement of gross alpha activity in non-saline water — Thick source method
Water quality — Measurement of gross alpha activity in non-saline water — Thick source method
ISO 9696:2007 specifies a method for the determination of gross alpha activity in non-saline waters for alpha‑emitting radionuclides which are not volatile at 350 °C. It is possible to determine supported volatile radionuclides measured to an extent determined by half-life, matrix retention (of the volatile species) and the duration of measurement (counting time). The method is applicable to raw and potable waters.
Qualité de l'eau — Mesurage de l'activité alpha globale des eaux non salines — Méthode par source concentrée
L'ISO 9696:2007 spécifie une méthode de détermination de l'activité alpha globale dans les eaux non salines, applicable aux radionucléides émetteurs alpha non volatils à 350 °C. Le dosage des radionucléides volatils fixés sur support est possible dans une certaine mesure, qui dépend de la demi-vie, de la rétention sur le support et de la durée du mesurage (temps de comptage). La méthode décrite est applicable à l'analyse des eaux brutes et des eaux potables.
Kakovost vode - Merjenje skupne alfa aktivnosti v neslanih vodah - Metoda robustnega vira
Ta mednarodni standard določa metodo določevanja skupne alfa aktivnosti v neslanih vodah za alfa oddajne radionuklide, ki niso hlapni pri 350 °C. Določevanje podprtih hlapnih radionuklidov, merjenih v obsegu, določeno z razpolovne dobe in zadrževanjem matrice (hlapnih vrst) in trajanjem merjenja (čas merjenja) je možno. Metoda se uporablja za neobdelane in pitne vode. Razpon uporabe je odvisen od količine zadržane snovi v vodi in od značilnosti delovanja (stopnje štetja iz ozadja in učinkovitost štetja) števca.
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МЕЖДУНАРОДНЫЙ ISO
СТАНДАРТ 9696
Второе издание
2007-11-15
Качество воды. Измерение суммарной
альфа-активности в
неминерализованной воде. Метод с
применением концентрированного
источника
Water quality — Measurement of gross alpha-activity in non-saline
water — Thick source method
Ссылочный номер
ISO 9696:2007(R)
©
ISO 2007
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ISO 9696:2007(R)
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ISO 9696:2007(R)
Содержание Страница
Предисловие .iv
1 Область применения .1
2 Нормативные ссылки .1
3 Обозначения, определения и единицы измерения .2
4 Принцип.3
5 Реактивы и оборудование.3
6 Процедура.5
7 Контроль загрязнения .8
8 Выражение результатов .9
9 Протокол испытания.11
Библиография.13
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ISO 9696:2007(R)
Предисловие
Международная организация по стандартизации ISO является всемирной федерацией национальных
организаций по стандартизации (комитетов-членов ISO). Разработка международных стандартов
обычно осуществляется техническими комитетами ISO. Каждый комитет-член, заинтересованный в
деятельности, для которой был создан технический комитет, имеет право быть представленным в этом
комитете. Международные правительственные и неправительственные организации, имеющие связи с
ISO, также принимают участие в работах. ISO осуществляет тесное сотрудничество с международной
электротехнической комиссией (IEC) по всем вопросам стандартизации в области электротехники.
Проекты международных стандартов разрабатываются по правилам, указанным в Директивах ISO/IEC,
Часть 2.
Главная задача технических комитетов состоит в разработке международных стандартов. Проекты
международных стандартов, принятые техническими комитетами, рассылаются комитетам-членам на
голосование. Их опубликование в качестве международных стандартов требует одобрения, по
меньшей мере, 75 % комитетов-членов, принимающих участие в голосовании.
Обращается внимание на возможность патентования некоторых элементов данного международного
стандарта. ISO не несет ответственности за идентификацию какого-либо или всех таких патентных
прав.
ISO 9696 был подготовлен Техническим комитетом ISO/TC 147, Качество воды.
Это второе издание отменяет и заменяет первое издание (ISO 9696:1992), которое технически
пересмотрено.
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МЕЖДУНАРОДНЫЙ СТАНДАРТ ISO 9696:2007(R)
Качество воды. Измерение суммарной альфа-
активности в неминерализованной воде. Метод с
применением концентрированного источника
ПРЕДУПРЕЖДЕНИЕ — Лица, использующие этот международный стандарт, должны быть
знакомы с обычной лабораторной практикой. Настоящий стандарт не касается всех проблем
безопасности, если таковые имеются, связанные с его использованием. Пользователь сам
должен устанавливать соответствующие меры по безопасности и защите здоровья и
обеспечивать соответствие национальным регламентам.
ВАЖНО — Важно, чтобы испытания, соответствующие этому международному стандарту,
проводились соответственно обученным персоналом.
1 Область применения
Настоящий международный стандарт устанавливает метод определения суммарной альфа-активности
для альфа-излучающих радионуклидов в неминерализованных водах, которые являются не летучими
при 350 °C. Можно определять летучие радионуклиды, измеряемые в пределах, определяемых
периодом полураспада, сохранением матрицы (летучих видов) и продолжительностью измерения
(время счета).
Метод применим для сырой и питьевой воды.
Область применения зависит от количества суспендированного вещества в воде и от рабочих
характеристик (фоновая скорость счета и эффективность счета) счетчика.
2 Нормативные ссылки
Следующие ссылочные нормативные документы являются обязательными при применении данного
документа. Для жестких ссылок применяется только цитированное издание документа. Для плавающих
ссылок необходимо использовать самое последнее издание нормативного ссылочного документа
(включая любые изменения).
ISO 31-9, Величины и единицы измерения. Часть 9. Атомная и ядерная физика
ISO 5667-1, Качество воды. Отбор проб. Часть. 1. Руководство по составлению программ и
методикам отбора проб
ISO 5667-3, Качество воды. Отбор проб. Часть. 3. Руководство по хранению и обращению с
пробами воды
ISO 5667-14, Качество воды. Отбор проб. Часть. 14. Руководство по обеспечению качества при
отборе проб природных вод и обращении с ними
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ISO 9696:2007(R)
ISO/IEC 17025, Общие требования к компетентности испытательных и калибровочных
лабораторий
Guide to the expression of uncertainty in measurement (GUM), BIPM, IEC, IFCC, ISO, IUPAC, IUPAP, OIML
3 Обозначения, определения и единицы измерения
Применительно к настоящему документу используются определения, обозначения и сокращения,
определенные в ISO 31-9, а также следующие обозначения.
V Объем пробы воды, в литрах
t
V Объем анализируемой пробы, в литрах, эквивалентный массе твердого вещества в
чашке
m Масса, в миллиграммах, прокаленного остатка из объема V
m Масса остатка, осажденного из пробы в чашке, в миллиграммах
r
A Альфа-активность калибровочного источника, в беккерелях
c Концентрация альфа-активности, в беккерелях на литр
A
t Время фонового счета, в секундах
0
t Время счета образца, в секундах
g
r Фоновая скорость счета, в секунду
0
r Суммарная скорость счета образца, в секунду
g
r Калибровочная скорость счета, в секунду
s
ε Счет эффективности установленного калибровочного источника
S Площадь дна емкости в квадратных миллиметрах
uc() Стандартная погрешность, связанная с результатом измерения, в беккерелях на литр
A
U Расширенная погрешность, вычисленная посредством Uk=⋅u(a) при k = 1, 2., в
беккерелях на литр
∗
c Порог принятия решения, в беккерелях на литр
A
#
c Предел детектирования, в беккерелях на литр
A
<>
cc, Нижний и верхний пределы доверительного интервала, в беккерелях на литр
A A
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ISO 9696:2007(R)
4 Принцип
Суммарную альфа-активность определяют посредством пропорционального счета или счета
сцинтилляций от твердого водного остатка в измерительной ёмкости. Из-за сильной абсорбции
осажденного остатка считается, что альфа-излучение от его поверхности пропорционально альфа-
активности осадка.
Суммарное определение альфа-активности является не абсолютным определением альфа-
радиоактивного содержания в пробе, а относительным определением специфического альфа-
излучателя, который составляет эталонный калибровочный источник. Этот тип определения известен
также как определение альфа-индекса.
Пробу окисляют для обеспечения устойчивости, выпаривают почти до сухости, преобразуют в
сульфатную форму и затем прокаливают при 350 °C. Часть остатка переносят в измерительную чашку
и измеряют альфа-активность, подсчитывая ее посредством детектора альфа-частиц или системы
счета, предварительно калиброванной по альфа-излучающему эталону, и вычисляют концентрацию
альфа-активности.
5 Реактивы и оборудование
5.1 Реактивы
Кроме аттестованного стандартного раствора, все реактивы должны быть признанной аналитической
чистоты и не иметь никакой измеримой альфа-активности.
ПРИМЕЧАНИЕ Метод приготовления холостых реактивов для контроля эндемической радиоактивности
приводится в Приложении 7.
5.1.1 Вода, дистиллированная или деионизированная, для всех применений.
5.1.2 Аттестованный стандартный раствор
Калибровочная лаборатория устанавливает прослеживаемую связь своих собственных измерительных
эталонов и измерительных приборов с Международной системой единиц (SI) посредством
неразрывной цепи калибровок или сличений, связывая их с соответствующими первичными эталонами
единиц измерения SI. Связь с единицами измерения SI может быть получена путем ссылки на
национальные измерительные эталоны. Национальные измерительные эталоны могут быть
первичными эталонами, которые являются первичными реализациями единиц SI или согласованными
представлениями единиц SI на основе фундаментальных физических постоянных, или они могут быть
вторичными эталонами, которые являются эталонами, калиброванными другим национальным
метрологическим институтом. При использовании внешних калибровочных услуг прослеживаемость
измерения должна быть обеспечена использованием калибровочных услуг от лабораторий, которые
могут продемонстрировать компетентность, способность к измерению и прослеживаемость.
Сертификаты калибровки, выпускаемые этими лабораториями, должны содержать результаты
измерения, включающие погрешность измерения и/или заявление о соответствии
идентифицированным метрологическим характеристикам.
Выбор альфа-эталона будет зависеть от знания того, какой тип радиоактивного загрязнения может
присутствовать в анализируемых водах. В общем, это означает выбор между природными и
искусственными альфа-излучателями.
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ISO 9696:2007(R)
Среди эталонных растворов искусственных альфа-излучающих радионуклидов обычно используются
241 239 239 241
Am и Pu. Когда используется Pu, следует учитывать примесь Pu, так как она приводит к росту
241 241
Am в приготовленных эталонных растворах источников. Когда используется Am, следует
учитывать потенциальные помехи гамма-излучения или перекрестные помехи альфа-бета излучения
(см. Ссылку [1]).
ПРИМЕЧАНИЕ 1 Урановое соединение аттестованного природного или известного изотопного состава имеет
одно спорное преимущество, состоящее в том, что удельную активность можно вычислить из установленных
физических постоянных и из данных относительного содержания изотопа, которые не зависят от калибровочных
процедур в конкретной организации.
ПРИМЕЧАНИЕ 2 Кроме того, поскольку энергии альфа-излучений из урановых изотопов меньше, чем из
искусственных трансурановых нуклидов, использование уранового эталона имеет тенденцию к высоким
результатам для трансурановых нуклидов. Некоторые организации предпочитают ошибиться в сторону
повышения в ситуациях, когда истинный состав не известен.
5.1.3 Азотная кислота, c(HNO ) = 8 моль/л.
3
5.1.4 Серная кислота, c(H SO ) = 18 моль/л, ρ = 1,84 г/мл, массовая доля w(H SO ) = 95 %.
2 4 2 4
5.1.5 Летучие органические растворители.
Метанол и ацетон.
5.1.6 Винилацетат.
5.1.7 Сульфат кальция, CaSO .
4
226 210
Так как соли кальция могут содержать незначительные количества Ra и/или Pb, должен
проводиться контроль на присутствие этих нуклидов.
5.2 Оборудование
5.2.1 Обычное лабораторное оборудование.
5.2.2 Счетчик альфа-частиц.
Альфа-активность подсчитывают, используя или сцинтилляционный экран из сульфида цинка,
активированного серебром, кремниевый детектор заряженных частиц [ионно-имплантированный
кремниевый детектор или детектор с поверхностным барьером (SSB)] или поточный газовый
−2
пропорциональный счетчик (без окошка и с окошком u 100 мкг · см ).
Если используется поточный газовый пропорциональный счетчик, рекомендуется выбирать окошко для
альфа-излучения таким образом, чтобы перекрестные помехи бета-альфа излучений приближались к
нулю.
Если используются поточные газовые пропорциональные счетчики без окошек, следует проводить
регулярный контроль на присутствие возможного загрязнения счетной системы посредством счета
холостых образцов.
ПРИМЕЧАНИЕ Природа твердого вещества источника, альфа-активность которого должна быть подсчитана,,
может привести к проблемам загрязнения при работе в вакууме (как в случае SSB) или поточных газовых
системах (используемых в пропорциональных счетчиках).
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ISO 9696:2007(R)
−2
5.2.3 Емкости (выпарительные и измерительные чашки), толщиной как минимум 2,5 мг · мм
−2
(250 мг · см ), из нержавеющей стали; счетный лоток.
ПРИМЕЧАНИЕ 1 Диаметр используемой чашки определяется требованиями счетчика, т.е. диаметром детектора
и размерами держателя источника.
ПРИМЕЧАНИЕ 2 Источник должен быть равномерно распределенным, поэтому некоторые операторы находят,
что легче это сделать на полированной металлической поверхности, тогда как другие предпочитают использовать
вытравленные или шероховатые емкости (для этой цели применяются пескоструйная обработка или химическое
травление).
5.2.4 Муфельная печь, способная поддерживать температуру (350 ± 10) °C.
6 Процедура
6.1 Отбор проб
Отбор проб, манипулирование и хранение выполняются по ISO 5667-1, ISO 5667-3 и ISO 5667-14.
Фильтрацию проводят непосредственно при сборе и перед окислением, если оно имеет место, в том
случае, когда требуется измерение активности фильтрованной пробы воды.
ПРИМЕЧАНИЕ Окисление пробы воды будет минимизировать потерю радиоактивного материала из раствора
посредством адсорбции. Если оно выполняется перед фильтрацией, раствор будет десорбировать радиоактивный
материал, уже адсорбированный на твердое вещество.
6.2 Предварительная обработка
Определение полного содержания твердого вещества в воде выполняется для определения
наименьшего объема воды, необходимого для измерения. Делая обязательное допущение на
изменение состава, обусловленное прокаливан
...
INTERNATIONAL ISO
STANDARD 9696
Second edition
2007-11-15
Water quality — Measurement of gross
alpha activity in non-saline water — Thick
source method
Qualité de l'eau — Mesurage de l'activité alpha globale des eaux non
salines — Méthode par source concentrée
Reference number
ISO 9696:2007(E)
©
ISO 2007
---------------------- Page: 1 ----------------------
ISO 9696:2007(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
COPYRIGHT PROTECTED DOCUMENT
© ISO 2007
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2007 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 9696:2007(E)
Contents Page
Foreword. iv
1 Scope . 1
2 Normative references . 1
3 Symbols, definitions and units. 2
4 Principle. 2
5 Reagents and equipment . 3
6 Procedure . 4
7 Contamination check. 7
8 Expression of results . 8
9 Test report . 10
Bibliography . 11
© ISO 2007 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 9696:2007(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 9696 was prepared by Technical Committee ISO/TC 147, Water quality.
This second edition cancels and replaces the first edition (ISO 9696:1992), which has been technically revised.
iv © ISO 2007 – All rights reserved
---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 9696:2007(E)
Water quality — Measurement of gross alpha activity
in non-saline water — Thick source method
WARNING — Persons using this International Standard should be familiar with normal laboratory
practice. This standard does not purport to address all of the safety problems, if any, associated with
its use. It is the responsibility of the user to establish appropriate safety and health practices and to
ensure compliance with any national regulatory conditions.
IMPORTANT — It is absolutely essential that tests conducted in accordance with this International
Standard be carried out by suitably trained staff.
1 Scope
This International Standard specifies a method for the determination of gross alpha activity in non-saline
waters for alpha-emitting radionuclides which are not volatile at 350 °C. It is possible to determine supported
volatile radionuclides measured to an extent determined by half-life, matrix retention (of the volatile species)
and the duration of measurement (counting time).
The method is applicable to raw and potable waters.
The range of application depends on the amount of suspended matter in the water and on the performance
characteristics (background count rate and counting efficiency) of the counter.
2 Normative references
The following referenced documents are indispensable for the application 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 31-9, Quantities and units — Part 9: Atomic and nuclear physics
ISO 5667-1, Water quality — Sampling — Part 1: Guidance on the design of sampling programmes and
sampling techniques
ISO 5667-3, Water quality — Sampling — Part 3: Guidance on the preservation and handling of water
samples
ISO 5667-14, Water quality — Sampling — Part 14: Guidance on quality assurance of environmental water
sampling and handling
ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories
Guide to the expression of uncertainty in measurement (GUM), BIPM, IEC, IFCC, ISO, IUPAC, IUPAP, OIML
© ISO 2007 – All rights reserved 1
---------------------- Page: 5 ----------------------
ISO 9696:2007(E)
3 Symbols, definitions and units
For the purposes of this document, the definitions, symbols and abbreviations defined in ISO 31-9, as well as
the following symbols, apply.
V Volume of the water sample, in litres
t
V Volume of test sample, in litres, equivalent to the mass of solid on the planchet
m Mass, in milligrams, of ignited residue from volume V
m Mass of the residue deposited on the planchet sample, in milligrams
r
A Alpha activity of the calibration source, in becquerels
c Alpha activity concentration, in becquerels per litre
A
t Background counting time, in seconds
0
t Sample counting time, in seconds
g
r Background count rate, per second
0
r Sample gross count rate, per second
g
r Calibration count rate, per second
s
ε Counting efficiency of the specified calibration source
S Area of the planchet, in square millimetres
uc() Standard uncertainty associated with the measurement result, in becquerels per litre
A
U Expanded uncertainty calculated by Uk=⋅u(a) with k = 1, 2., in becquerels per litre
∗
c Decision threshold, in becquerels per litre
A
#
c Detection limit, in becquerels per litre
A
cc, Lower and upper limits of the confidence interval, in becquerels per litre
AA
4 Principle
Gross alpha radioactivity is determined by using proportional counting or solid scintillation counting on water
residue deposited on a planchet. Due to the strong absorption of the residue deposit, it is considered that the
alpha emission from the surface is proportional to the alpha activity of the deposit.
Gross alpha determination is not an absolute determination of the sample alpha radioactive content, but a
relative determination referring to a specific alpha emitter which constitutes the standard calibration source.
This type of determination is also known as alpha index.
The sample is acidified to stabilize it, evaporated almost to dryness, converted to the sulfate form and then
ignited at 350 °C. A portion of the residue is transferred to a planchet and the alpha activity measured by
counting in an alpha-particle detector or counting system previously calibrated against an alpha-emitting
standard and the alpha activity concentration calculated.
2 © ISO 2007 – All rights reserved
---------------------- Page: 6 ----------------------
ISO 9696:2007(E)
5 Reagents and equipment
5.1 Reagents
Except for the certified reference solution, all reagents shall be of recognized analytical grade and shall not
contain any measurable alpha activity.
NOTE A method for preparing reagent blanks to check for endemic radioactivity or contamination is given in Clause 7.
5.1.1 Water, distilled or deionized, for all applications.
5.1.2 Certified reference solution.
A calibration laboratory establishes traceability of its own measurement standards and measuring instruments
to the International System of Units (SI) by means of an unbroken chain of calibrations or comparisons linking
them to relevant primary standards of the SI units of measurement. The link to SI units may be achieved by
reference to national measurement standards. National measurement standards may be primary standards,
which are primary realizations of the SI units or agreed representations of SI units based on fundamental
physical constants, or they may be secondary standards which are standards calibrated by another national
metrology institute. When using external calibration services, traceability of measurement shall be assured by
the use of calibration services from laboratories that can demonstrate competence, measurement capability
and traceability. The calibration certificates issued by these laboratories shall contain the measurement
results, including the measurement uncertainty and/or a statement of compliance with an identified
metrological specification.
The choice of alpha standard will depend on knowledge of the type of radioactive contaminant likely to be
present in the waters being tested. In general, this amounts to a choice between naturally occurring and
man-made alpha emitters.
241 239
Among standard solutions of artificial alpha-emitting radionuclides, Am and Pu are commonly used.
239 241 241
When Pu is used, the presence of Pu impurity shall be taken into account as it leads to growth of Am
241
in prepared standard solutions of sources. When Am is used, the potential interferences of its gamma
emission, or alpha-beta crosstalk shall be taken into account (see Reference [1]).
NOTE 1 A uranium compound of certified natural or known isotopic composition has one arguable advantage, in that
its specific activity can be calculated from established physical constants and isotopic abundance data which are
independent of the calibration procedures of a particular organization.
NOTE 2 Furthermore, since the energies of the alpha emissions from uranium isotopes are less than those from the
artificial transuranic nuclides, the use of a uranium standard tends to give a high result for transuranics. Some authorities
prefer to err on the high side in situations where the true composition is unknown.
5.1.3 Nitric acid, c(HNO ) = 8 mol/l.
3
5.1.4 Sulfuric acid, c(H SO ) = 18 mol/l, ρ = 1,84 g/ml, mass fraction w(H SO ) = 95 %.
2 4 2 4
5.1.5 Volatile organic solvents.
Methanol and acetone.
5.1.6 Vinyl acetate.
5.1.7 Calcium sulfate, CaSO .
4
226 210
As calcium salts may contain trace amounts of Ra and/or Pb, checks for the presence of these nuclides
shall be made.
© ISO 2007 – All rights reserved 3
---------------------- Page: 7 ----------------------
ISO 9696:2007(E)
5.2 Equipment
5.2.1 Usual laboratory equipment.
5.2.2 Alpha counter.
Alpha activity shall be counted using either a silver-activated zinc sulfide scintillation screen, a silicon
charged-particle detector [ion-implanted silicon or surface barrier detector (SSB)] or a gas-flow proportional
−2
counter (windowless or with a window of u 100 µg · cm ).
If a gas-flow proportional counter is used, it is advisable to choose the alpha window so that the beta-alpha
cross-talk is close to zero.
If windowless gas-flow proportional counters are used, carry out regular checks for possible contamination of
the counting system by counting blank samples.
NOTE The particulate nature of the source to be counted can give rise to contamination problems if operated in a
vacuum (as in the case of an SSB) or gas flow systems (as used in a proportional counter).
−2 −2
5.2.3 Planchets, of thickness at least 2,5 mg · mm (250 mg · cm ), lipped and of stainless steel;
counting tray.
NOTE 1 The diameter of the planchet to be used is determined by the counter requirements, i.e. the detector diameter
and source holder dimensions.
NOTE 2 An evenly spread source is required and some workers find it easier to produce this on a polished metal
surface, whereas others prefer to use an etched or roughened planchet (sand blasting and chemical etching has been
applied for this purpose).
5.2.4 Muffle furnace, capable of maintaining a temperature of (350 ± 10) °C.
6 Procedure
6.1 Sampling
Sampling, handling and storage of the water samples shall be done as specified in ISO 5667-1, ISO 5667-3
and ISO 5667-14.
Carry out filtration immediately on collection and before acidification if any, if it is desired to measure the
activity of the filtered sample of water.
NOTE Acidification of the water sample will minimize the loss of radioactivity material from solution by adsorption. If
carried out before filtration, it will desorb radioactive material already adsorbed on the particulate material.
6.2 Pretreatment
The determination of the total solids content of the water may be performed to determine the smallest volume
of water needed for the measurement. Making due allowance for changes in composition due to ignition at
350 °C and sulfation of the residue, calculate the volume of sample required to produce a mass of solid
residue slightly in excess of R such as:
m
r
R = W 0,1 (1)
S
Use this as a guide to the volume of sample required for the concentration stage which follows.
The an
...
SLOVENSKI STANDARD
SIST ISO 9696:2010
01-september-2010
Kakovost vode - Merjenje skupne alfa aktivnosti v neslanih vodah - Metoda
robustnega vira
Water quality - Measurement of gross alpha activity in non-saline water - Thick source
method
Qualité de l'eau - Mesurage de l'activité alpha globale des eaux non salines - Méthode
par source concentrée
Ta slovenski standard je istoveten z: ISO 9696:2007
ICS:
13.060.60 Preiskava fizikalnih lastnosti Examination of physical
vode properties of water
17.240 Merjenje sevanja Radiation measurements
SIST ISO 9696:2010 en,fr
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST ISO 9696:2010
---------------------- Page: 2 ----------------------
SIST ISO 9696:2010
INTERNATIONAL ISO
STANDARD 9696
Second edition
2007-11-15
Water quality — Measurement of gross
alpha activity in non-saline water — Thick
source method
Qualité de l'eau — Mesurage de l'activité alpha globale des eaux non
salines — Méthode par source concentrée
Reference number
ISO 9696:2007(E)
©
ISO 2007
---------------------- Page: 3 ----------------------
SIST ISO 9696:2010
ISO 9696:2007(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
COPYRIGHT PROTECTED DOCUMENT
© ISO 2007
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2007 – All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 9696:2010
ISO 9696:2007(E)
Contents Page
Foreword. iv
1 Scope . 1
2 Normative references . 1
3 Symbols, definitions and units. 2
4 Principle. 2
5 Reagents and equipment . 3
6 Procedure . 4
7 Contamination check. 7
8 Expression of results . 8
9 Test report . 10
Bibliography . 11
© ISO 2007 – All rights reserved iii
---------------------- Page: 5 ----------------------
SIST ISO 9696:2010
ISO 9696:2007(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 9696 was prepared by Technical Committee ISO/TC 147, Water quality.
This second edition cancels and replaces the first edition (ISO 9696:1992), which has been technically revised.
iv © ISO 2007 – All rights reserved
---------------------- Page: 6 ----------------------
SIST ISO 9696:2010
INTERNATIONAL STANDARD ISO 9696:2007(E)
Water quality — Measurement of gross alpha activity
in non-saline water — Thick source method
WARNING — Persons using this International Standard should be familiar with normal laboratory
practice. This standard does not purport to address all of the safety problems, if any, associated with
its use. It is the responsibility of the user to establish appropriate safety and health practices and to
ensure compliance with any national regulatory conditions.
IMPORTANT — It is absolutely essential that tests conducted in accordance with this International
Standard be carried out by suitably trained staff.
1 Scope
This International Standard specifies a method for the determination of gross alpha activity in non-saline
waters for alpha-emitting radionuclides which are not volatile at 350 °C. It is possible to determine supported
volatile radionuclides measured to an extent determined by half-life, matrix retention (of the volatile species)
and the duration of measurement (counting time).
The method is applicable to raw and potable waters.
The range of application depends on the amount of suspended matter in the water and on the performance
characteristics (background count rate and counting efficiency) of the counter.
2 Normative references
The following referenced documents are indispensable for the application 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 31-9, Quantities and units — Part 9: Atomic and nuclear physics
ISO 5667-1, Water quality — Sampling — Part 1: Guidance on the design of sampling programmes and
sampling techniques
ISO 5667-3, Water quality — Sampling — Part 3: Guidance on the preservation and handling of water
samples
ISO 5667-14, Water quality — Sampling — Part 14: Guidance on quality assurance of environmental water
sampling and handling
ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories
Guide to the expression of uncertainty in measurement (GUM), BIPM, IEC, IFCC, ISO, IUPAC, IUPAP, OIML
© ISO 2007 – All rights reserved 1
---------------------- Page: 7 ----------------------
SIST ISO 9696:2010
ISO 9696:2007(E)
3 Symbols, definitions and units
For the purposes of this document, the definitions, symbols and abbreviations defined in ISO 31-9, as well as
the following symbols, apply.
V Volume of the water sample, in litres
t
V Volume of test sample, in litres, equivalent to the mass of solid on the planchet
m Mass, in milligrams, of ignited residue from volume V
m Mass of the residue deposited on the planchet sample, in milligrams
r
A Alpha activity of the calibration source, in becquerels
c Alpha activity concentration, in becquerels per litre
A
t Background counting time, in seconds
0
t Sample counting time, in seconds
g
r Background count rate, per second
0
r Sample gross count rate, per second
g
r Calibration count rate, per second
s
ε Counting efficiency of the specified calibration source
S Area of the planchet, in square millimetres
uc() Standard uncertainty associated with the measurement result, in becquerels per litre
A
U Expanded uncertainty calculated by Uk=⋅u(a) with k = 1, 2., in becquerels per litre
∗
c Decision threshold, in becquerels per litre
A
#
c Detection limit, in becquerels per litre
A
cc, Lower and upper limits of the confidence interval, in becquerels per litre
AA
4 Principle
Gross alpha radioactivity is determined by using proportional counting or solid scintillation counting on water
residue deposited on a planchet. Due to the strong absorption of the residue deposit, it is considered that the
alpha emission from the surface is proportional to the alpha activity of the deposit.
Gross alpha determination is not an absolute determination of the sample alpha radioactive content, but a
relative determination referring to a specific alpha emitter which constitutes the standard calibration source.
This type of determination is also known as alpha index.
The sample is acidified to stabilize it, evaporated almost to dryness, converted to the sulfate form and then
ignited at 350 °C. A portion of the residue is transferred to a planchet and the alpha activity measured by
counting in an alpha-particle detector or counting system previously calibrated against an alpha-emitting
standard and the alpha activity concentration calculated.
2 © ISO 2007 – All rights reserved
---------------------- Page: 8 ----------------------
SIST ISO 9696:2010
ISO 9696:2007(E)
5 Reagents and equipment
5.1 Reagents
Except for the certified reference solution, all reagents shall be of recognized analytical grade and shall not
contain any measurable alpha activity.
NOTE A method for preparing reagent blanks to check for endemic radioactivity or contamination is given in Clause 7.
5.1.1 Water, distilled or deionized, for all applications.
5.1.2 Certified reference solution.
A calibration laboratory establishes traceability of its own measurement standards and measuring instruments
to the International System of Units (SI) by means of an unbroken chain of calibrations or comparisons linking
them to relevant primary standards of the SI units of measurement. The link to SI units may be achieved by
reference to national measurement standards. National measurement standards may be primary standards,
which are primary realizations of the SI units or agreed representations of SI units based on fundamental
physical constants, or they may be secondary standards which are standards calibrated by another national
metrology institute. When using external calibration services, traceability of measurement shall be assured by
the use of calibration services from laboratories that can demonstrate competence, measurement capability
and traceability. The calibration certificates issued by these laboratories shall contain the measurement
results, including the measurement uncertainty and/or a statement of compliance with an identified
metrological specification.
The choice of alpha standard will depend on knowledge of the type of radioactive contaminant likely to be
present in the waters being tested. In general, this amounts to a choice between naturally occurring and
man-made alpha emitters.
241 239
Among standard solutions of artificial alpha-emitting radionuclides, Am and Pu are commonly used.
239 241 241
When Pu is used, the presence of Pu impurity shall be taken into account as it leads to growth of Am
241
in prepared standard solutions of sources. When Am is used, the potential interferences of its gamma
emission, or alpha-beta crosstalk shall be taken into account (see Reference [1]).
NOTE 1 A uranium compound of certified natural or known isotopic composition has one arguable advantage, in that
its specific activity can be calculated from established physical constants and isotopic abundance data which are
independent of the calibration procedures of a particular organization.
NOTE 2 Furthermore, since the energies of the alpha emissions from uranium isotopes are less than those from the
artificial transuranic nuclides, the use of a uranium standard tends to give a high result for transuranics. Some authorities
prefer to err on the high side in situations where the true composition is unknown.
5.1.3 Nitric acid, c(HNO ) = 8 mol/l.
3
5.1.4 Sulfuric acid, c(H SO ) = 18 mol/l, ρ = 1,84 g/ml, mass fraction w(H SO ) = 95 %.
2 4 2 4
5.1.5 Volatile organic solvents.
Methanol and acetone.
5.1.6 Vinyl acetate.
5.1.7 Calcium sulfate, CaSO .
4
226 210
As calcium salts may contain trace amounts of Ra and/or Pb, checks for the presence of these nuclides
shall be made.
© ISO 2007 – All rights reserved 3
---------------------- Page: 9 ----------------------
SIST ISO 9696:2010
ISO 9696:2007(E)
5.2 Equipment
5.2.1 Usual laboratory equipment.
5.2.2 Alpha counter.
Alpha activity shall be counted using either a silver-activated zinc sulfide scintillation screen, a silicon
charged-particle detector [ion-implanted silicon or surface barrier detector (SSB)] or a gas-flow proportional
−2
counter (windowless or with a window of u 100 µg · cm ).
If a gas-flow proportional counter is used, it is advisable to choose the alpha window so that the beta-alpha
cross-talk is close to zero.
If windowless gas-flow proportional counters are used, carry out regular checks for possible contamination of
the counting system by counting blank samples.
NOTE The particulate nature of the source to be counted can give rise to contamination problems if operated in a
vacuum (as in the case of an SSB) or gas flow systems (as used in a proportional counter).
−2 −2
5.2.3 Planchets, of thickness at least 2,5 mg · mm (250 mg · cm ), lipped and of stainless steel;
counting tray.
NOTE 1 The diameter of the planchet to be used is determined by the counter requirements, i.e. the detector diameter
and source holder dimensions.
NOTE 2 An evenly spread source is required and some workers find it easier to produce this on a polished metal
surface, whereas others prefer to use an etched or roughened planchet (sand blasting and chemical etching has been
applied for this purpose).
5.2.4 Muffle furnace, capable of maintaining a temperature of (350 ± 10) °C.
6 Procedure
6.1 Sampling
Sampling, handling and storage of the water samples shall be done as specified in ISO 5667-1, ISO 5667-3
and ISO 5667-14.
Carry out filtration immediately on collection and before acidification if any, if it is desired to measure the
activity of the filtered sample of water.
NOTE Acidification of the water sample will minimize the loss of radioactivity material from solution by adsorption. If
carried out before filtration, it will desorb radioactive material already adsorbed on the particulate material.
6.2
...
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Kakovost vode - Merjenje celotne alfa aktivnosti v neslanih vodah - Metoda robustnega viraQualité de l'eau - Mesurage de l'activité alpha globale des eaux non salines - Méthode par source concentréeWater quality - Measurement of gross alpha activity in non-saline water - Thick source method17.240Merjenje sevanjaRadiation measurements13.060.60Preiskava fizikalnih lastnosti vodeExamination of physical properties of waterICS:Ta slovenski standard je istoveten z:ISO 9696:2007oSIST ISO 9696:2009en,fr01-junij-2009oSIST ISO 9696:2009SLOVENSKI
STANDARD
oSIST ISO 9696:2009
Reference numberISO 9696:2007(E)© ISO 2007
INTERNATIONAL STANDARD ISO9696Second edition2007-11-15Water quality — Measurement of gross alpha activity in non-saline water —Thick source method Qualité de l'eau — Mesurage de l'activité alpha globale des eaux non salines — Méthode par source concentrée
oSIST ISO 9696:2009
ISO 9696:2007(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
COPYRIGHT PROTECTED DOCUMENT
©
ISO 2007 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Case postale 56 • CH-1211 Geneva 20 Tel.
+ 41 22 749 01 11 Fax
+ 41 22 749 09 47 E-mail
copyright@iso.org Web
www.iso.org Published in Switzerland
ii © ISO 2007 – All rights reserved
oSIST ISO 9696:2009
ISO 9696:2007(E) © ISO 2007 – All rights reserved iiiContents Page Foreword.iv 1 Scope.1 2 Normative references.1 3 Symbols, definitions and units.2 4 Principle.2 5 Reagents and equipment.3 6 Procedure.4 7 Contamination check.7 8 Expression of results.8 9 Test report.10 Bibliography.11
oSIST ISO 9696:2009
ISO 9696:2007(E) iv © ISO 2007 – All rights reserved 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. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. 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. ISO 9696 was prepared by Technical Committee ISO/TC 147, Water quality. This second edition cancels and replaces the first edition (ISO 9696:1992), which has been technically revised.
oSIST ISO 9696:2009
INTERNATIONAL STANDARD ISO 9696:2007(E) © ISO 2007 – All rights reserved 1Water quality — Measurement of gross alpha activity in non-saline water — Thick source method WARNING — Persons using this International Standard should be familiar with normal laboratory practice. This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditions. IMPORTANT — It is absolutely essential that tests conducted in accordance with this International Standard be carried out by suitably trained staff. 1 Scope This International Standard specifies a method for the determination of gross alpha activity in non-saline waters for alpha-emitting radionuclides which are not volatile at 350 °C. It is possible to determine supported volatile radionuclides measured to an extent determined by half-life, matrix retention (of the volatile species) and the duration of measurement (counting time). The method is applicable to raw and potable waters. The range of application depends on the amount of suspended matter in the water and on the performance characteristics (background count rate and counting efficiency) of the counter. 2 Normative references The following referenced documents are indispensable for the application 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 31-9, Quantities and units — Part 9: Atomic and nuclear physics ISO 5667-1, Water quality — Sampling — Part 1: Guidance on the design of sampling programmes and sampling techniques ISO 5667-3, Water quality — Sampling — Part 3: Guidance on the preservation and handling of water samples ISO 5667-14, Water quality — Sampling — Part 14: Guidance on quality assurance of environmental water sampling and handling ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories Guide to the expression of uncertainty in measurement (GUM), BIPM, IEC, IFCC, ISO, IUPAC, IUPAP, OIML oSIST ISO 9696:2009
ISO 9696:2007(E) 2 © ISO 2007 – All rights reserved 3 Symbols, definitions and units For the purposes of this document, the definitions, symbols and abbreviations defined in ISO 31-9, as well as the following symbols, apply. Vt Volume of the water sample, in litres V Volume of test sample, in litres, equivalent to the mass of solid on the planchet m Mass, in milligrams, of ignited residue from volume V
mr
Mass of the residue deposited on the planchet sample, in milligrams A Alpha activity of the calibration source, in becquerels
cA Alpha activity concentration, in becquerels per litre t0 Background counting time, in seconds tg Sample counting time, in seconds r0 Background count rate, per second rg Sample gross count rate, per second rs Calibration count rate, per second ε Counting efficiency of the specified calibration source S Area of the planchet, in square millimetres ()Auc Standard uncertainty associated with the measurement result, in becquerels per litre
U Expanded uncertainty calculated by ()Ukua=⋅ with k = 1, 2., in becquerels per litre
Ac∗ Decision threshold, in becquerels per litre #Ac Detection limit, in becquerels per litre ,AAcc Lower and upper limits of the confidence interval, in becquerels per litre
4 Principle Gross alpha radioactivity is determined by using proportional counting or solid scintillation counting on water residue deposited on a planchet. Due to the strong absorption of the residue deposit, it is considered that the alpha emission from the surface is proportional to the alpha activity of the deposit. Gross alpha determination is not an absolute determination of the sample alpha radioactive content, but a relative determination referring to a specific alpha emitter which constitutes the standard calibration source. This type of determination is also known as alpha index. The sample is acidified to stabilize it, evaporated almost to dryness, converted to the sulfate form and then ignited at 350 °C. A portion of the residue is transferred to a planchet and the alpha activity measured by counting in an alpha-particle detector or counting system previously calibrated against an alpha-emitting standard and the alpha activity concentration calculated. oSIST ISO 9696:2009
ISO 9696:2007(E) © ISO 2007 – All rights reserved 35 Reagents and equipment 5.1 Reagents Except for the certified reference solution, all reagents shall be of recognized analytical grade and shall not contain any measurable alpha activity. NOTE A method for preparing reagent blanks to check for endemic radioactivity or contamination is given in Clause 7. 5.1.1 Water, distilled or deionized, for all applications. 5.1.2 Certified reference solution. A calibration laboratory establishes traceability of its own measurement standards and measuring instruments to the International System of Units (SI) by means of an unbroken chain of calibrations or comparisons linking them to relevant primary standards of the SI units of measurement. The link to SI units may be achieved by reference to national measurement standards. National measurement standards may be primary standards, which are primary realizations of the SI units or agreed representations of SI units based on fundamental physical constants, or they may be secondary standards which are standards calibrated by another national metrology institute. When using external calibration services, traceability of measurement shall be assured by the use of calibration services from laboratories that can demonstrate competence, measurement capability and traceability. The calibration certificates issued by these laboratories shall contain the measurement results, including the measurement uncertainty and/or a statement of compliance with an identified metrological specification. The choice of alpha standard will depend on knowledge of the type of radioactive contaminant likely to be present in the waters being tested. In general, this amounts to a choice between naturally occurring and man-made alpha emitters. Among standard solutions of artificial alpha-emitting radionuclides, 241Am and 239Pu are commonly used. When 239Pu is used, the presence of 241Pu impurity shall be taken into account as it leads to growth of 241Am in prepared standard solutions of sources. When 241Am is used, the potential interferences of its gamma emission, or alpha-beta crosstalk shall be taken into account (see Reference [1]). NOTE 1 A uranium compound of certified natural or known isotopic composition has one arguable advantage, in that its specific activity can be calculated from established physical constants and isotopic abundance data which are independent of the calibration procedures of a particular organization. NOTE 2 Furthermore, since the energies of the alpha emissions from uranium isotopes are less than those from the artificial transuranic nuclides, the use of a uranium standard tends to give a high result for transuranics. Some authorities prefer to err on the high side in situations where the true composition is unknown. 5.1.3 Nitric acid, c(HNO3) = 8 mol/l. 5.1.4 Sulfuric acid, c(H2SO4) = 18 mol/l, ρ
= 1,84 g/ml, mass fraction w(H2SO4) = 95 %. 5.1.5 Volatile organic solvents. Methanol and acetone. 5.1.6 Vinyl acetate. 5.1.7 Calcium sulfate, CaSO4. As calcium salts may contain trace amounts of 226Ra and/or 210Pb, checks for the presence of these nuclides shall be made. oSIST ISO 9696:2009
ISO 9696:2007(E) 4 © ISO 2007 – All rights reserved 5.2 Equipment 5.2.1 Usual laboratory equipment. 5.2.2 Alpha counter. Alpha activity shall be counted using either a silver-activated zinc sulfide scintillation screen, a silicon charged-particle detector [ion-implanted silicon or surface barrier detector (SSB)] or a gas-flow proportional counter (windowless or with a window of u 100 µg · cm−2). If a gas-flow proportional counter is used, it is advisable to choose the alpha window so that the beta-alpha cross-talk is close to zero. If windowless gas-flow proportional counters are used, carry out regular checks for possible contamination of the counting system by counting blank samples. NOTE The particulate nature of the source to be counted can give rise to contamination problems if operated in a vacuum (as in the case of an SSB) or gas flow systems (as used in a proportional counter). 5.2.3 Planchets, of thickness at least 2,5 mg · mm−2 (250 mg · cm−2), lipped and of stainless steel; counting tray. NOTE 1 The diameter of the planchet to be used is determined by the counter requirements, i.e. the detector diameter and source holder dimensions. NOTE 2 An evenly spread source is required and some workers find it easier to produce this on a polished metal surface, whereas others prefer to use an etched or roughened planchet (sand blasting and chemical etching has been applied for this purpose). 5.2.4 Muffle furnace, capable of maintaining a temperature of (350 ± 10) °C. 6 Procedure 6.1 Sampling Sampling, handling and storage of the water samples shall be done as specified in ISO 5667-1, ISO 5667-3 and ISO 5667-14. Carry out filtration immediately on collection and before acidification if any, if it is desired to measure the activity of the filtered sample of water. NOTE Acidification of the water sample will minimize the loss of radioactivity material from solution by adsorption. If carried out b
...
NORME ISO
INTERNATIONALE 9696
Deuxième édition
2007-11-15
Qualité de l'eau — Mesurage de l'activité
alpha globale des eaux non salines —
Méthode par source concentrée
Water quality — Measurement of gross alpha activity in non-saline
water — Thick source method
Numéro de référence
ISO 9696:2007(F)
©
ISO 2007
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ISO 9696:2007(F)
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ii © ISO 2007 – Tous droits réservés
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ISO 9696:2007(F)
Sommaire Page
Avant-propos. iv
1 Domaine d'application. 1
2 Références normatives. 1
3 Termes, définitions et symboles . 2
4 Principe . 2
5 Réactifs et appareillage. 3
6 Mode opératoire . 4
7 Contrôle de contamination. 8
8 Expression des résultats. 8
9 Rapport d’essai . 10
Bibliographie . 12
© ISO 2007 – Tous droits réservés iii
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ISO 9696:2007(F)
Avant-propos
L'ISO (Organisation internationale de normalisation) est une fédération mondiale d'organismes nationaux de
normalisation (comités membres de l'ISO). L'élaboration des Normes internationales est en général confiée
aux comités techniques de l'ISO. Chaque comité membre intéressé par une étude a le droit de faire partie du
comité technique créé à cet effet. Les organisations internationales, gouvernementales et non
gouvernementales, en liaison avec l'ISO participent également aux travaux. L'ISO collabore étroitement avec
la Commission électrotechnique internationale (CEI) en ce qui concerne la normalisation électrotechnique.
Les Normes internationales sont rédigées conformément aux règles données dans les Directives ISO/CEI,
Partie 2.
La tâche principale des comités techniques est d'élaborer les Normes internationales. Les projets de Normes
internationales adoptés par les comités techniques sont soumis aux comités membres pour vote. Leur
publication comme Normes internationales requiert l'approbation de 75 % au moins des comités membres
votants.
L'attention est appelée sur le fait que certains des éléments du présent document peuvent faire l'objet de
droits de propriété intellectuelle ou de droits analogues. L'ISO ne saurait être tenue pour responsable de ne
pas avoir identifié de tels droits de propriété et averti de leur existence.
L'ISO 9696 a été élaborée par le comité technique ISO/TC 147, Qualité de l'eau.
Cette deuxième édition annule et remplace la première édition (ISO 9696:1992), qui a fait l'objet d'une
révision technique.
iv © ISO 2007 – Tous droits réservés
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NORME INTERNATIONALE ISO 9696:2007(F)
Qualité de l'eau — Mesurage de l'activité alpha globale
des eaux non salines — Méthode par source concentrée
AVERTISSEMENT — Il convient que les personnes utilisant la présente Norme internationale
connaissent les bonnes pratiques de laboratoire usuelles. La présente Norme internationale n’a pas
pour objectif d’aborder toutes les questions relatives à la sécurité associées à sa mise en œuvre. Il est
de la responsabilité de l’utilisateur de mettre en place les consignes de sécurité et de protection
individuelle appropriées et de s’assurer de leur conformité avec la législation nationale en vigueur.
IMPORTANT — Il est absolument essentiel que les essais réalisés conformément à la présente Norme
internationale soient menés par un personnel qualifié.
1 Domaine d'application
La présente Norme internationale spécifie une méthode de détermination de l’activité alpha globale dans les
eaux non salines, applicable aux radionucléides émetteurs alpha non volatils à 350 °C. Le dosage des
radionucléides volatils fixés sur support est possible dans une certaine mesure, qui dépend de la demi-vie, de
la rétention sur le support et de la durée du mesurage (temps de comptage).
La méthode décrite est applicable à l’analyse des eaux brutes et des eaux potables.
La gamme de validité de la méthode dépend de la quantité de matière en suspension contenue dans l’eau et
des caractéristiques du compteur (taux de comptage du fond de rayonnement et rendement de comptage).
2 Références normatives
Les documents de référence suivants sont indispensables pour l'application du présent document. Pour les
références datées, seule l'édition citée s'applique. Pour les références non datées, la dernière édition du
document de référence s'applique (y compris les éventuels amendements).
ISO 31-9, Grandeurs et unités — Partie 9: Physique atomique et nucléaire
ISO 5667-1, Qualité de l'eau — Échantillonnage — Partie 1: Lignes directrices pour la conception des
programmes et des techniques d'échantillonnage
ISO 5667-3, Qualité de l'eau — Échantillonnage — Partie 3: Lignes directrices pour la conservation et la
manipulation des échantillons d'eau
ISO 5667-14, Qualité de l'eau — Échantillonnage — Partie 14: Lignes directrices pour le contrôle de la qualité
dans l'échantillonnage et la manutention des eaux environnementales
ISO/CEI 17025, Exigences générales concernant la compétence des laboratoires d'étalonnages et d'essais
Guide pour l’expression de l’incertitude de mesure (GUM), BIPM, CEI, FICC, ISO, OIML, UICPA, UIPPA
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ISO 9696:2007(F)
3 Termes, définitions et symboles
Pour les besoins du présent document, les termes, définitions et symboles donnés dans l‘ISO 31-9 ainsi que
les symboles suivants, s’appliquent.
V Volume de l’échantillon d’eau, en litres
t
V Volume de l’aliquote, en litres, équivalent à la masse de résidu sur la coupelle
m Masse, en milligrammes, du résidu calciné du volume V
m Masse de résidu déposé sur la coupelle, en milligrammes
r
A Activité alpha de la source d’étalonnage, en becquerels
c Activité volumique, en becquerels par litre
A
t Temps de comptage du mouvement propre, en secondes
0
t Temps de comptage de l’échantillon, en secondes
g
r Taux de comptage du mouvement propre, par seconde
0
r Taux de comptage brut de l’échantillon, par seconde
g
r Taux de comptage de la source d’étalonnage, par seconde
s
ε Rendement de comptage de l’étalon radioactif
S Surface de la coupelle, en millimètres carrés
uc() Incertitude-type de l’activité volumique, en becquerels par litre
A
U Incertitude élargie, calculée par Uk=⋅u(a) avec k = 1, 2., en becquerels par litre
∗
c Seuil de décision, en becquerels par litre
A
#
c Limite de détection, en becquerels par litre
A
cc, Limites inférieure et supérieure de l’intervalle de confiance, en becquerels par litre
AA
4 Principe
La radioactivité alpha globale est déterminée en mesurant l’activité du résidu d’évaporation d’un échantillon
d’eau déposé sur une coupelle, en utilisant un compteur proportionnel ou un compteur à scintillation solide.
Compte tenu de l’importance du phénomène d’absorption dans le résidu, on considère que l’émission alpha
émise par la surface est proportionnelle à l’activité alpha du dépôt.
La détermination de l’activité alpha globale n’est pas une détermination absolue de la radioactivité alpha de
l’échantillon, mais une détermination relative par rapport à un radioélément spécifique émetteur alpha qui
constitue la source d’étalonnage. Ce type de détermination est également connu sous le nom d’indice alpha.
2 © ISO 2007 – Tous droits réservés
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ISO 9696:2007(F)
L’échantillon est stabilisé par acidification, évaporé jusqu’à dessiccation presque totale, transformé en sulfate
puis calciné à 350 °C. Une partie du résidu est transférée sur une coupelle et l’activité alpha mesurée par
comptage dans un système de comptage préalablement étalonné avec une source alpha de référence et
l’activité volumique alpha est ensuite calculée.
5 Réactifs et appareillage
5.1 Réactifs
Excepté pour la solution certifiée de référence, tous les réactifs doivent être de qualité analytique reconnue et
ne pas avoir d’activité alpha mesurable.
NOTE Une méthode de préparation des blancs pour contrôle de la radioactivité endémique ou de la contamination
est indiquée dans l’Article 7.
5.1.1 Eau, distillée ou déminéralisée, pour toutes les applications.
5.1.2 Solution certifiée de référence.
Un laboratoire d’étalonnage assure la traçabilité de ses propres étalons et instruments de mesure au Système
International (SI) au moyen de chaînes ininterrompues d’étalonnages ou d’intercomparaisons les raccordant
aux étalons primaires du SI d'unités. Le lien au SI d'unités peut être effectué en se référant à des étalons
nationaux. Les étalons nationaux peuvent être des étalons primaires qui sont des matérialisations des unités
SI ou des représentations reconnues des unités SI basées sur des constantes physiques fondamentales, il
peut aussi s’agir d’étalons secondaires raccordés à un autre institut national de métrologie. Lorsqu'il est fait
appel à des services d’étalonnage extérieurs, la traçabilité des mesures doit être assurée en faisant appel à
des laboratoires capables de démontrer leur compétence, leur capacité de mesure et leur raccordement. Les
certificats d’étalonnage émis par ces laboratoires doivent obligatoirement comporter les résultats de mesure, y
compris l’incertitude de mesure et/ou un certificat de conformité avec une spécification métrologique
identifiée.
Le choix de l’étalon alpha sera fonction du type de contaminants radioactifs susceptibles d’être présents dans
l’eau à analyser. En général, cela revient à choisir entre des émetteurs alpha artificiels ou présents à l’état
naturel.
241
Parmi les solutions d’étalonnage des radionucléides artificiels émetteurs alpha, les plus utilisées sont Am
239 239 241
et Pu. En cas d’utilisation de Pu, la présence de l’impureté Pu doit être prise en compte puisqu’elle
241
peut induire une augmentation de la présence de Am dans les solutions d’étalonnage préparées. En cas
241
d’utilisation de Am, les interférences possibles avec ses émissions gamma, ou les réjections alpha-bêta,
doivent être prises en compte (voir Référence [1]).
NOTE 1 L’emploi d’un composé de l’uranium de composition isotopique certifiée naturelle, ou connue, présente un
avantage non négligeable puisqu’il est possible de calculer son activité massique à partir de constantes physiques
connues et de données relatives aux teneurs isotopiques, indépendamment de la méthode d’étalonnage employée par un
organisme donné.
NOTE 2 Par ailleurs, les particules alpha émises par les isotopes de l’uranium ont des énergies inférieures à celles des
particules émises par les transuraniens. L’emploi d’un étalon d’uranium tend donc à donner un résultat élevé pour les
transuraniens. Certains organismes officiels préfèrent commettre une erreur par excès lorsque la composition isotopique
réelle est inconnue.
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ISO 9696:2007(F)
5.1.3 Acide nitrique, c(HNO ) = 8 mol/l.
3
5.1.4 Acide sulfurique, c(H SO ) = 18 mol/l, ρ = 1,84 g/ml, fraction massique w(H SO ) = 95 %
2 4 2 4
5.1.5 Solvants organiques volatils.
Méthanol et acétone.
5.1.6 Acétate de vinyle.
5.1.7 Sulfate de calcium (CaSO ).
4
226 210
Les sels de calcium pouvant contenir des traces de Ra et/ou de Pb, il y aura lieu d’effectuer des
contrôles de détection de ces nucléides.
5.2 Appareillage
5.2.1 Matériel courant de laboratoire.
5.2.2 Compteur alpha.
Le comptage de l’activité alpha doit être effectué en utilisant un des systèmes suivants: un détecteur à
scintillation solide de sulfure de zinc activé à l’argent ou un détecteur à semi-conducteur [jonction en silicium
implantée ou détecteur à barrière de surface en silicium (SSB)], ou encore un compteur proportionnel à gaz
–2
(avec ou sans fenêtre d’épaisseur u 100 µg·cm ).
Si l’on utilise un compteur proportionnel à gaz, il est conseillé de choisir un système avec fenêtre alpha, ainsi
la réjection bêta-alpha sera proche de zéro.
Si l’on utilise des systèmes sans fenêtre, contrôler régulièrement la contamination éventuelle du système, en
effectuant un comptage sur un échantillon à blanc entre chaque analyse de source.
NOTE L’analyse de certaines sources de type particulier peut poser des problèmes de contamination des systèmes
de comptage sous vide (comme dans le cas de détecteurs à barrière de surface en silicium) ou à courant gazeux (tels
qu’utilisés dans des compteurs proportionnels).
–2 –2
5.2.3 Coupelles, d’une épaisseur au moins égale à 2,5 mg⋅mm (250 mg⋅cm ), en acier inoxydable, avec
un rebord; plateaux de comptage.
NOTE 1 Le diamètre de la coupelle est choisi en fonction des caractéristiques du compteur, c’est-à-dire du diamètre du
détecteur et des dimensions de l’élément porte-source.
NOTE 2 II est nécessaire de répartir uniformément la source. Certains opérateurs trouvent cela plus facile à réaliser
sur une surface de métal poli, d’autres préfèrent utiliser une surface décapée ou rugueuse (on procède par décapage au
sable ou par corrosion chimique).
5.2.4 Four à moufle, permettant de maintenir la température à (350 ± 10) °C.
6 Mode opératoire
6.1 Échantillonnage
L’échantillonnage, le prélèvement et la conservation des échantillons d’eau doivent être conformes à
l’ISO 5667-1, à l’ISO 5667-3 et à l’ISO 5667-14.
Si l’on désire mesurer l’activité de l’échantillon d’eau filtrée, procéder à la filtration immédiatement après le
prélèvement et avant I’acidification.
4 © ISO 2007 – Tous droits réservés
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ISO 9696:2007(F)
NOTE L’acidification réduit la perte par adsorption des éléments radioactifs en solution. Si elle est effectuée avant la
filtration, elle entraîne la désorption des éléments radioactifs déjà adsorbés sur les particules en suspension.
6.2 Étape préliminaire
La détermination de la teneur totale de l’eau en matières solides doit être réalisée pour déterminer le plus petit
volume d’eau nécessaire pour la mesure. En tenant compte des modifications de composition qui résultent de
la calcination à 350 °C et de la sulfatation du résidu, calculer le volume d’échantillon nécessaire pour obtenir
un résidu solide de masse légèrement supérieure à R tel que:
m
r
R= W 0,1 (1)
S
En fonction du résultat obtenu, prélever un échantillon de volume suffisant pou
...
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