Iodine charcoal sorbents for nuclear facilities - Method for defining sorption capacity index (ISO 18417:2017)

The scope of ISO 18417:2017 covers
-      iodine sorbents for nuclear power plants, nuclear facilities, research and other nuclear reactors,
-      iodine sorbents for laboratories, including nuclear medicine, and
-      iodine sorbents for sampling equipment on sample lines.
ISO 18417:2017 applies to iodine sorbents manufacturers and operators in order to measure the actual performance of these sorbents and their sorption capacity for radioiodine.
ISO 18417:2017 applies to granulated and crushed iodine sorbents based on activated charcoal (hereinafter referred to as "sorbents") used for trapping gaseous radioiodine and its compounds. This document establishes the method and conditions for defining sorption capacity index in a laboratory.

Jodkohlenstoffsorptionsmittel für kerntechnische Anlagen - Verfahren zur Bestimmung des Sorptionsvermögensindexes (ISO 18417:2017)

Der Anwendungsbereich dieses Dokuments deckt Folgendes ab:
- Jodsorptionsmittel für Kernkraftwerke, Kernanlagen, Forschungseinrichtungen und andere Kernreaktoren,
- Jodsorptionsmittel für Labore, einschließlich Nuklearmedizin, und
- Jodsorptionsmittel für Probenahmegeräte auf Probenahmeanlagen.
Dieses Dokument gilt für Hersteller von Jodsorptionsmitteln sowie Betreiber, und hilft dabei, die tatsächliche Leistung der Sorptionsmittel und ihre Sorptionsfähigkeit für Radioiod zu messen.
Dieses Dokument gilt für granulierte und zerkleinerte Jodsorptionsmittel auf Basis von Aktivkohle (im Folgenden „Sorptionsmittel“" genannt), die zum Aufnehmen von gasförmigem Radiojod und seinen Verbindungen verwendet werden. Dieses Dokument legt das Verfahren und die Bedingungen für die Definition des Sorptionskapazitätsindex in einem Labor fest.

Pièges à iode pour installations nucléaires - Méthode pour définir la capacité de rétention (ISO 18417:2017)

Le domaine d'application de l'ISO 18417:2017 couvre
-      les dispositifs adsorbants d'iode pour centrales nucléaires, installations nucléaires, centres de recherche et autres réacteurs nucléaires;
-      les dispositifs adsorbants d'iode pour laboratoires, y compris pour les applications en médecine nucléaire; et
-      les dispositifs adsorbants d'iode pour matériel d'échantillonnage sur les lignes de prélèvement.
ISO 18417:2017 s'applique aux fabricants et exploitants d'installations nucléaires avec dispositifs adsorbants d'iode afin qu'ils puissent mesurer la performance réelle de ces adsorbants et leur capacité de rétention de l'iode radioactif.
ISO 18417:2017 s'applique aussi bien aux adsorbants d'iode en granulés que ceux en grains concassés basés sur le charbon actif (ci-après désignés, les «adsorbants») utilisés pour piéger l'iode radioactif gazeux et ses composés. Le présent document spécifie la méthode et les conditions permettant de définir, au laboratoire, l'indice de capacité de rétention.

Jodni ogleni sorbenti za jedrske objekte - Metoda za določanje indeksa sorpcijske zmogljivosti (ISO 18417:2017)

Standard ISO 18417:2017 zajema naslednje vidike:
– jodni sorbenti za jedrske elektrarne, jedrske objekte, raziskave in druge jedrske reaktorje,
– jodni sorbenti za laboratorije, vključno z nuklearno medicino, in
– jodni sorbenti za opremo za vzorčenje na vzorčnih linijah.
Standard ISO 18417:2017 se uporablja za izdelovalce in upravljavce jodnih sorbentov z namenom merjenja dejanske učinkovitosti sorbentov in njihove sorpcijske zmogljivosti za radioaktivni jod.
Standard ISO 18417:2017 se uporablja za zrnate ali drobljene jodne sorbente, ki so osnovani na aktivnem oglju (v nadaljevanju »sorbenti«) in se uporabljajo za zajetje plinskega radioaktivnega joda in njegovih spojin. Ta dokument določa metodo in pogoje za določanje indeksa sorpcijske zmogljivosti v laboratoriju.

General Information

Status
Published
Publication Date
11-Jun-2019
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
12-Jun-2019
Completion Date
12-Jun-2019

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SLOVENSKI STANDARD
SIST EN ISO 18417:2019
01-september-2019

Jodni ogleni sorbenti za jedrske objekte - Metoda za določanje indeksa sorpcijske

zmogljivosti (ISO 18417:2017)

Iodine charcoal sorbents for nuclear facilities - Method for defining sorption capacity

index (ISO 18417:2017)

Jodkohlenstoffsorptionsmittel für kerntechnische Anlagen - Verfahren zur Bestimmung

des Sorptionsvermögensindexes (ISO 18417:2017)

Pièges à iode pour installations nucléaires - Méthode pour définir la capacité de rétention

(ISO 18417:2017)
Ta slovenski standard je istoveten z: EN ISO 18417:2019
ICS:
13.280 Varstvo pred sevanjem Radiation protection
SIST EN ISO 18417:2019 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 18417:2019
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SIST EN ISO 18417:2019
EN ISO 18417
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2019
EUROPÄISCHE NORM
ICS 13.280
English Version
Iodine charcoal sorbents for nuclear facilities - Method for
defining sorption capacity index (ISO 18417:2017)

Pièges à iode pour installations nucléaires - Méthode Jodkohlenstoffsorptionsmittel für kerntechnische

pour définir la capacité de rétention (ISO 18417:2017) Anlagen - Verfahren zur Bestimmung des

Sorptionsvermögensindexes (ISO 18417:2017)
This European Standard was approved by CEN on 8 March 2019.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 18417:2019 E

worldwide for CEN national Members.
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SIST EN ISO 18417:2019
EN ISO 18417:2019 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 18417:2019
EN ISO 18417:2019 (E)
European foreword

The text of ISO 18417:2017 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 18417:2019 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 December 2019, and conflicting national standards

shall be withdrawn at the latest by December 2019.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

According to the CEN-CENELEC Internal Regulations, the national standards organizations of the

following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,

France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,

Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
Endorsement notice

The text of ISO 18417:2017 has been approved by CEN as EN ISO 18417:2019 without any modification.

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SIST EN ISO 18417:2019
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SIST EN ISO 18417:2019
INTERNATIONAL ISO
STANDARD 18417
First edition
2017-03
Iodine charcoal sorbents for nuclear
facilities — Method for defining
sorption capacity index
Pièges à iode pour installations nucléaires — Méthode pour définir la
capacité de rétention
Reference number
ISO 18417:2017(E)
ISO 2017
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SIST EN ISO 18417:2019
ISO 18417:2017(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, Published in Switzerland

All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved
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SIST EN ISO 18417:2019
ISO 18417:2017(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3  Terms and definitions ..................................................................................................................................................................................... 1

4 Principles of the method .............................................................................................................................................................................. 2

5 Preparation of the test .................................................................................................................................................................................... 4

5.1 General ........................................................................................................................................................................................................... 4

5.2 Removal of air impurity and humidity into the installation ............................................................................ 4

5.3 Radioactive methyl iodide used for sorbent testing ............................................................................................... 5

5.4 Preparation of sorbent samples ............................................................................................................................................... 5

5.5 Measuring devices................................................................................................................................................................................ 6

5.6 Conditions for achieving equilibrium during the test ........................................................................................... 6

5.7 Safe conditions for workers and members of the public .................................................................................... 6

6 Test conditions ....................................................................................................................................................................................................... 7

7  Sorbent testing ....................................................................................................................................................................................................... 7

8 Test performance ................................................................................................................................................................................................. 9

9 Determination of the sorption capacity index....................................................................................................................10

9.1 Sorption capacity index determination ..........................................................................................................................10

9.2 Calculating sorption capacity index ...................................................................................................................................11

9.3 Uncertainties of measurements ............................................................................................................................................12

10  Documenting test results ..........................................................................................................................................................................13

Annex A (normative) Format of test report (for the customer) ............................................................................................14

Annex B (normative) Format of internal test report ........................................................................................................................15

Annex C (normative) Measurements results.............................................................................................................................................16

Annex D (informative) Example of expected results for sorption capacity index ..............................................17

Bibliography .............................................................................................................................................................................................................................19

© ISO 2017 – All rights reserved iii
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SIST EN ISO 18417:2019
ISO 18417:2017(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on 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 the following

URL: w w w . i s o .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.
iv © ISO 2017 – All rights reserved
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SIST EN ISO 18417:2019
ISO 18417:2017(E)
Introduction

Iodine sorbents are extensively used in nuclear facilities to remove radioiodine from gases and air in

off-gas cleaning systems and ventilation installations. The sorbents are very important for protection

of the members of the public and environment from iodine radionuclides radiation.

In the normal operation of nuclear installations, the main hazard comes from radioactive isotopes of

131 133 129

iodine; as examples, for reactors I and a minor extent I, for fuel processing facilities I, etc.

Iodine is one of the main contributors of the radiation impact on the environment. Under abnormal and

132 134 135

accident conditions, some other isotopes I, I and I have also some significant effects on the

[3]
total iodine dose (thyroid dose) .

The volatile radioiodine forms can occur in the gaseous radioactive wastes as elemental iodine, the

simplest organic compound methyl iodide, and some others such as hydrogen iodide under reducing

conditions.

Radioactive iodine can create a serious danger to the members of the public and workers in abnormal

and accident conditions at nuclear facilities as far as the exposure in these conditions could be much

higher than the exposure due to the natural background radiation.

The need to prevent widespread dispersal of gaseous radioiodine from nuclear facilities is a major

purpose of iodine sorbents. It is universally recognized that radioactive methyl iodide is the less readily

removable radioiodine form. The removal of radioactive iodine from gaseous radioactive wastes at

nuclear facilities is almost always performed with the help of impregnated activated charcoals that

have become often accepted as the preferred iodine sorbents used in these facilities. Impregnated

charcoals require a high efficiency especially from humid gases containing iodine in order to trap all

the iodine gaseous compounds.
[2][4]
Two types of tests are considered : laboratory and in situ tests.

— Laboratory tests are done to establish the performance characteristics of the charcoal to be used in

retention systems under specified operating conditions.

— In situ tests are done to obtain a measure of the performance of retention systems under appropriate

operational conditions.

This document concerns only the laboratory tests. Laboratory tests of representative samples of

charcoal (e.g. new charcoal, aged charcoal from iodine absorbers, etc.) are performed to establish their

efficiency for a given test agent under specified conditions.

The quality of sorbents and its potential application at nuclear facilities can be estimated by means of

a criterion that defines specifically the sorption capacity of the sorbent. Such criterion is called in this

document the sorption capacity index.

The index is defined by the result of a laboratory test on the basis of radioiodine activity distribution

inside the sorbent. This index characterizes the total kinetic sorption process for established test

conditions and show whether the sorbent can be used as iodine filters for nuclear facilities. One example

of criteria is given in Annex D.

This document provides a method to determine the quantitative quality of a sorbent and also to

compare the performance of different iodine sorbents at the specified conditions. It is useful for users

of iodine sorbents (filter or sorbent manufacturers as well as operators).
© ISO 2017 – All rights reserved v
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SIST EN ISO 18417:2019
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SIST EN ISO 18417:2019
INTERNATIONAL STANDARD ISO 18417:2017(E)
Iodine charcoal sorbents for nuclear facilities — Method
for defining sorption capacity index
1 Scope
The scope of this document covers

— iodine sorbents for nuclear power plants, nuclear facilities, research and other nuclear reactors,

— iodine sorbents for laboratories, including nuclear medicine, and
— iodine sorbents for sampling equipment on sample lines.

This document applies to iodine sorbents manufacturers and operators in order to measure the actual

performance of these sorbents and their sorption capacity for radioiodine.

This document applies to granulated and crushed iodine sorbents based on activated charcoal

(hereinafter referred to as “sorbents”) used for trapping gaseous radioiodine and its compounds. This

document establishes the method and conditions for defining sorption capacity index in a laboratory.

2 Normative references
There are no normative references in this document.
3  Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
3.1
gaseous radioactive wastes

wastes that contain radioactive material in gas form for which no further use is foreseen and have

radionuclides at concentrations or activities greater than clearance levels as established by a

regulatory body
3.2
discharge

planned and controlled release of (gas or liquid) radioactive material to the environment

3.3
mass transfer zone

defined zone (range) of sorbent volume in which the phenomena of substance mass transfer from gas to

solid phases takes place
3.4
iodine sorbent
sorbent intended for trapping radioiodine in gaseous radioactive wastes
© ISO 2017 – All rights reserved 1
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SIST EN ISO 18417:2019
ISO 18417:2017(E)
3.5
free volume

void between grains or crushed grains of the sorbent inside the whole volume containing the sorbent

Note 1 to entry: The free volume can be expressed as in Formula (1):
VV=⋅χ (1)
fr sorb
where
V free volume;
χ fraction free volume in sorbent volume;
V sorbent volume.
sorb
3.6
contact time
gas flow transit time through sorbent layer
Note 1 to entry: Contact time τ is expressed using Formula (2):
τ= (2)
col
where
Q the volumetric gas flow rate in the inlet sectional column.
col

Note 2 to entry: The contact time defined here does not consider the geometric volume of the sample, but only its

free volume.
3.7
bulk density
sorb

ratio between granulated or crushed grains sorbent mass (definite granulation) and the total volume

containing the sorbent
3.8
sorption capacity index

criterion indicating the degree of reduction of gaseous radioiodine in the gas flowing through the

sorbent under specified test conditions

Note 1 to entry: The index is valid only for a specific chemical form of the radioactive gas. In this document, the

index has been calculated for radioactive methyl iodide. The index can also be calculated with other gaseous

species, such as radioactive iodine, but the results cannot be compared with the ones obtained with radioactive

methyl iodide.
4 Principles of the method
The main rationale for the method defined in this document are the following:
131

— radioactive methyl iodide (CH I) is the most difficult form of radioiodine to trap in nuclear

facilities discharges;

— the distribution of radioactive methyl iodide along sorbent layer is exponential;

— there is an active mass transfer zone in the sorbent layer;
2 © ISO 2017 – All rights reserved
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SIST EN ISO 18417:2019
ISO 18417:2017(E)

— the amount of sorbed radioactive methyl iodide depends on the contact time between the gas and

sorbent.

The sorption capacity index indicates the degree by which radioactive methyl iodide concentration in

gas phase is reduced during the contact of the gas flow with the sorbent.
The principle of the method is the following:
— indoor laboratory air is used as carrier gas;

— air is transferred in the test plant by means of extraction device (fan, vacuum pump, etc.);

— in order to remove indoor laboratory air pollutants, aerosols and humidity, air flow passes through

an aerosol filter, an air conditioning system used for humidity (e.g. zeolite or dehumidifier) and

volatile compounds removal (e.g. activated charcoal);

— the humidity level shall be maintained to a specified value and be controlled. One example for this

humidity control is to split the total air flow and pass one of the flows through a second air condition

system (e.g. humidifier);

— the air temperature and air flow are regulated and measured before introduction in the sample to

test (e.g. the air temperature is control by heat insulation of the sectional column or to place it in a

vessel with controlled temperature);

— radioactive methyl iodide is injected into the carrier gas from a generator and then it is trapped in

the sectional columns containing the sorbent to be tested;

— before discharging the test gas, the air is passed through a protection column for radiation

protection issues and for control of the penetration radioiodine and to ensure a low level of iodine

active species in discharged air;

— each section test column is monitored for radioiodine content via gamma monitors (0,364 MeV

131
for I);
— the sorption capacity index is calculated using the formula given in Clause 9.

Figure 1 presents the principle of an example scheme of the test plant used for the method presented in

this document.
© ISO 2017 – All rights reserved 3
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SIST EN ISO 18417:2019
ISO 18417:2017(E)
Key
1 flowmeter
2 aerosol filter
3 dehumidifier
4 charcoal
5 injection of radioactive methyl iodide
6 generator of radioactive methyl iodide
7 humidifier
8 temperature controlled chamber
9 sectional column
10 protection column
11 vacuum pump
12 room air
13 controller humidity, temperature, absolute pressure and pressure drop

Figure 1 — Schematic of principle equipment and a process diagram of the test plant

5 Preparation of the test
5.1 General

Based on the typical arrangement proposed in Clause 4, the test involves the following stages.

5.2 Removal of air impurity and humidity into the installation

Removing air pollutant and controlling humidity and temperature are important for the tests because

these parameters can have a significant impact on the results. In order to clean the installation before

a new test, the indoor air is passed through an aerosol filter, dehumidifier and charcoal filter to remove

particulates, humidity and some volatile compounds. As an example, dehumidifier with zeolite warms

at the temperature 350 °C to 400 °C in vacuum during 6 h and activated carbon to warm at temperature

300 °C to 350 °C in vacuum during 6 h in order to avoid degradation of the charcoal properties.

4 © ISO 2017 – All rights reserved
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SIST EN ISO 18417:2019
ISO 18417:2017(E)
5.3  Radioactive methyl iodide used for sorbent testing
131

If radioiodide is supplied in ready-to-use form of radioactive methyl iodide (CH I) received from

producer, a certificate date and activity shall be required. It shall be stored in a dark place at conditions

that slows down the process of its decomposition into the molecular form (I ).
131 131

Otherwise, methyl iodide labelled with I isotope is produced by its isotopic exchange (e.g. with Na I

131 3

or K I without carrier). Its activity shall be defined and specified with a date. For this purpose, 2 cm

131 131

of methyl iodide are injected into the container with Na I or K I and kept at a room temperature

of 20 °C for 48 h. To define the mass activity concentration (Bq/g), three portions of 5 g of activated

carbon impregnated with triethylenediaminne (TEDA) are weighed and placed in weighing bottles, the

diameter of which is close to that of the test column. Three samples of 4 µl of radio-labelled methyl

iodide are taken and placed into weighing bottles with activated carbon. Activities of resulting samples

are measured and correlated with methyl iodide mass that is defined as the volume of samples taken

and methyl iodide density at the temperature of its storage.

Mean value of mass activity concentration is calculated. The mass activity concentration (expressed

in Bq/g) is used for calculation of the mass concentration of methyl iodide in the gas flow (see

Formula 8).
5.4 Preparation of sorbent samples

Range of granulated/crushed grains sizes and bulk density ρ of the sorbent sample are determined

sorb

if these data are absent. The methods used to determine grains size and the bulk density are defined

according to a national or international standard.

When filing each section of the column, the filling shall be made uniformly in each section such that

similar mass in each section is obtained, without specific compression or vibration.

The sectional column is used to conduct the sorbent test. Examples of such column and of a small section

inside the column are shown in Figure 2 and Figure 3.
Key
1 removable cover with inlet nozzle
2 sorbent-containing section
3 guide rod
4 bottom with outlet nozzle
Figure 2 — Column for sorbent testing
© ISO 2017 – All rights reserved 5
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SIST EN ISO 18417:2019
ISO 18417:2017(E)
Key
1 vessel
2 sealing ring
3 perforated diaphragm
4 sorbent
Figure 3 — Section of sorbent-containing column

The number of sections has to be adapted with regard to the uncertainties of the measurement.

5.5  Measuring devices
The uncertainties of the following measurement devices shall be known:
— temperature sensors;
— pressure sensors,
— relative humidity sensors;
— gamma activity detectors;
— flow rate sensors.
Typical uncertainties are given in 9.3.
5.6  Conditions for achieving equilibrium during the test

Prior to testing the sorbent in the sectional column, test conditions shall be maintained such that the

conditions for the equilibrium of water vapours inside the samples are achieved (humidifier conditions

at gas flow velocity, Q ). This is generally done in 16 h for around 15 cm thickness of sorbent.

col
5.7 Safe conditions for workers and members of the public

The tests use a radioactive form of iodine. Thus, the tests shall be performed following national

radiation protection regulations (for workers and members of the public) in force in the country. All

the handling with radioactive iodine solutions and iodine vapours shall be performed under protective

glove boxes. The glove box should be in a negative pressure enough to avoid to spread contaminated

flows to the rooms.

The test installations shall be equipped with specific protection devices allowing to efficiently reduce

the iodine releases towards the environment (e.g. protection columns represented in the equipment 10

of the Figure 1), connected to the air ventilation system of the building. Examples of protection columns

are made with silver impregnated zeolites, silver impregnated aluminium oxide and qualified activated

charcoal.
6 © ISO 2017 – All rights reserved
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SIST EN ISO 18417:2019
ISO 18417:2017(E)
6 Test conditions

In order to ensure accurate and comparable measurement of sorbent performance, the following

conditions shall be met.
The following parameters shall be specified with their accuracy:
— specified temperature;
— specified gas relative humidity;
— gas flow transit time through the sorbent layer (contact duration);
131
— concentration of CH I in gas;
— specified CH I mass concentration in gas.

The absolute pressure shall be measured for the test, and the accuracy of the measurement shall be

known.

The relative humidity and the gas flow of the test bench are set to achieve nominally each relative

humidity (RH) conditions for the sorbent on the scale 30 % RH to 90 % RH.

The following parameters are fixed, within range intervals, for the purpose of estimating the potential

to use sorbents under high relative humidity (abnormal) conditions and comparing the charcoal

performance index:

— specified gas relative humidity: (90,0 ± 3) % in order to cover accidental conditions;

— specified temperature: (30,0 ± 0,5) °C;

— gas flow transit time through the sorbent layer (contact duration) — contact time in the range from

0,20 s to 0,40 s;
131 3 3
...

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