Safe transport of radioactive materials - Leakage testing on packages (ISO 12807:2018)

This document specifies gas leakage test criteria and test methods for demonstrating that packages used to transport radioactive materials comply with the package containment requirements defined in the International Atomic Energy Agency (IAEA) Regulations for the Safe Transport of Radioactive Material for:
— design verification;
— fabrication verification;
— preshipment verification;
— periodic verification;
— maintenance verification.
This document describes a method for relating permissible activity release of the radioactive contents carried within a containment system to equivalent gas leakage rates under specified test conditions. This approach is called gas leakage test methodology. However, in this document it is recognized that other methodologies might be acceptable, provided that they demonstrate that any release of the radioactive contents will not exceed the regulatory requirements, and subject to agreement with the competent authority.
This document provides both overall and detailed guidance on the complex relationships between an equivalent gas leakage test and a permissible activity release rate. Whereas the overall guidance is universally agreed upon, the use of the detailed guidance shall be agreed upon with the competent authority during the Type B(U), Type B(M) or Type C packages certification process.
It should be noted that, for a given package, demonstration of compliance is not limited to a single methodology.
While this document does not require particular gas leakage test procedures, it does present minimum requirements for any test that is to be used. It is the responsibility of the package designer or consignor to estimate or determine the maximum permissible release rate of radioactivity to the environment and to select appropriate leakage test procedures that have adequate sensitivity.
This document pertains specifically to Type B(U), Type B(M) or Type C packages for which the regulatory containment requirements are specified explicitly.

Kernbrennstofftechnologie - Sicherer Transport von radioaktivem Material - Dichtheitsprüfung der Verpackung (ISO 12807:2018)

Dieses Dokument legt Prüfkriterien und Prüfverfahren für die Messung der Gasleckage fest, um nachzuweisen, dass Versandstücke für den Transport radioaktiven Materials die Anforderungen an sichere Verpackungen im Dokument Regulations for the Safe Transport of Radioactive Material der International Atomic Energy Agency (IAEA) erfüllen, für die
- Designverifizierung,
- Verifizierung bei der Fertigung,
- Verifizierung vor Versand,
- regelmäßige Verifizierung, und
- Verifizierung bei Wartung.
Dieses Dokument beschreibt ein Verfahren, mit der die zulässige Aktivitätsfreisetzung radioaktiven Inhalts in einem Umschließungssystem unter vorgegebenen Prüfbedingungen zu äquivalenten Gasleckageraten in Bezug gesetzt werden kann. Dieser Ansatz wird als die Gasleckage-Prüfmethodik bezeichnet. Jedoch wird in diesem Dokument anerkannt, dass auch andere Verfahren zulässig sein könnten, sofern mit ihnen nachgewiesen werden kann, dass eine Freisetzung des radioaktiven Inhalts die behördlichen Anforderungen nicht übersteigt und diese mit der zuständigen Behörde abgestimmt werden.
Dieses Dokument stellt sowohl eine allgemeine als auch eine detaillierte Anleitung zu den komplexen Beziehungen zwischen einer Prüfung der äquivalenten Gasleckage und einer zulässigen Aktivitäts-freisetzungsrate bereit. Während die allgemeine Anleitung allgemein anerkannt ist, muss die Anwendung der detaillierten Anleitung mit der zuständigen Behörde während der Zertifizierung von Versandstücken Typ B(U), Typ B(M) oder Typ C vereinbart werden.
Es wird darauf hingewiesen, dass der Nachweis der Erfüllung der Anforderung nicht auf eine einzelne Methodik beschränkt ist.
Dieses Dokument verlangt keine bestimmten Prüfverfahren für Gasleckagen, legt jedoch Mindestanforderungen für jede Prüfung fest, die angewandt wird. Der Konstrukteur oder Lieferant des Versandstücks ist für die Abschätzung oder Bestimmung der maximal zulässigen Freisetzungsrate von Radioaktivität in die Umgebung und für die Wahl der geeigneten Leckage-Prüfverfahren, die eine angemessene Empfindlichkeit aufweisen, verantwortlich.
Dieses Dokument bezieht sich gezielt auf Versandstücke Typ B(U), Typ B(M) oder Typ C, für die die behördlich festgesetzten Anforderungen an eine dichte Umschließung explizit festgelegt sind.

Sûreté des transports de matières radioactives - Contrôle de l'étanchéité des colis (ISO 12807:2018)

Le présent document donne les critères applicables aux essais d'étanchéité au gaz et les méthodes de contrôle permettant de vérifier que les colis utilisés pour transporter les matières radioactives sont conformes aux exigences pour le confinement définies dans le Règlement de transport des matières radioactives de l'Agence internationale de l'énergie atomique (AIEA), du point de vue des:
— contrôles à la conception;
— contrôles en cours de fabrication;
— contrôles avant expédition;
— contrôles périodiques;
— contrôles de maintenance.
Le présent document décrit une méthodologie qui permet d'établir une relation entre le relâchement d'activité admissible du contenu radioactif transporté dans une enveloppe de confinement et les flux de fuite équivalents d'un gaz, dans des conditions d'essai données. II s'agit de la méthodologie de contrôle d'étanchéité au gaz. Cependant, le présent document admet que d'autres méthodologies puissent être suivies, avec l'accord de l'autorité compétente, à condition qu'elles démontrent que toute perte de contenu radioactif n'excédera pas les exigences réglementaires.
Le présent document fournit des lignes directrices à la fois générales et détaillées sur les relations complexes entre un essai de flux de fuite équivalent et le taux admissible de relâchement d'activité. Étant donné que les lignes directrices générales sont reconnues universellement, l'utilisation des lignes directrices détaillées doit faire l'objet d'un accord avec l'autorité compétente lors de la certification des colis de type B(U), B(M) ou C.
II convient de noter que la démonstration de la conformité d'un colis donné n'est pas limitée à la mise en œuvre d'une seule méthodologie.
Bien que le présent document n'impose pas de méthode spécifique d'essai d'étanchéité au gaz, il indique des exigences minimales pour toute méthode susceptible d'être utilisée. II incombe au concepteur, ou à l'expéditeur du colis, d'estimer ou de déterminer, le taux de relâchement maximal admissible de matière radioactive dans l'environnement et de choisir des procédures d'essai d'étanchéité appropriées qui présentent la sensibilité requise.
Le présent document s'applique tout particulièrement aux colis de type B(U), B(M) ou C pour lesquels les exigences réglementaires pour le confinement sont spécifiées explicitement.

Varen prevoz radioaktivnih snovi - Preskušanje tesnjenja embalaže (ISO 12807:2018)

General Information

Status
Published
Public Enquiry End Date
30-Nov-2020
Publication Date
21-Feb-2021
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
18-Feb-2021
Due Date
25-Apr-2021
Completion Date
22-Feb-2021

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SLOVENSKI STANDARD
SIST EN ISO 12807:2021
01-april-2021
Varen prevoz radioaktivnih snovi - Preskušanje tesnjenja embalaže (ISO
12807:2018)

Safe transport of radioactive materials - Leakage testing on packages (ISO 12807:2018)

Kernbrennstofftechnologie - Sicherer Transport von radioaktivem Material -
Dichtheitsprüfung der Verpackung (ISO 12807:2018)

Sûreté des transports de matières radioactives - Contrôle de l'étanchéité des colis (ISO

12807:2018)
Ta slovenski standard je istoveten z: EN ISO 12807:2021
ICS:
13.280 Varstvo pred sevanjem Radiation protection
27.120.30 Cepljivi materiali in jedrska Fissile materials and nuclear
gorivna tehnologija fuel technology
SIST EN ISO 12807:2021 en,fr,de

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

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SIST EN ISO 12807:2021
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SIST EN ISO 12807:2021
EN ISO 12807
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2021
EUROPÄISCHE NORM
ICS 13.280; 27.120.30
English Version
Safe transport of radioactive materials - Leakage testing on
packages (ISO 12807:2018)

Sûreté des transports de matières radioactives - Kernbrennstofftechnologie - Sicherer Transport von

Contrôle de l'étanchéité des colis (ISO 12807:2018) radioaktivem Material - Dichtheitsprüfung der

Verpackung (ISO 12807:2018)
This European Standard was approved by CEN on 18 January 2021.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this

European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by

translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management

Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

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

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

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

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 12807:2021 E

worldwide for CEN national Members.
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SIST EN ISO 12807:2021
EN ISO 12807:2021 (E)
Contents Page

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

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SIST EN ISO 12807:2021
EN ISO 12807:2021 (E)
European foreword

The text of ISO 12807:2018 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 12807:2021 by Technical Committee CEN/TC 430 “Nuclear

energy, nuclear technologies, and radiological protection” the secretariat of which is held by AFNOR.

This European Standard shall be given the status of a national standard, either by publication of an

identical text or by endorsement, at the latest by August 2021, and conflicting national standards shall

be withdrawn at the latest by August 2021.

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

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

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

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

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the

United Kingdom.
Endorsement notice

The text of ISO 12807:2018 has been approved by CEN as EN ISO 12807:2021 without any modification.

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SIST EN ISO 12807:2021
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SIST EN ISO 12807:2021
INTERNATIONAL ISO
STANDARD 12807
Second edition
2018-09
Safe transport of radioactive
materials — Leakage testing on
packages
Sûreté des transports de matières radioactives — Contrôle de
l'étanchéité des colis
Reference number
ISO 12807:2018(E)
ISO 2018
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SIST EN ISO 12807:2021
ISO 12807:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved
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SIST EN ISO 12807:2021
ISO 12807:2018(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

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

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

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

4 Symbols and units ............................................................................................................................................................................................... 4

5 Regulatory requirements ............................................................................................................................................................................ 7

5.1 Relevant regulations........................................................................................................................................................................... 7

5.2 Regulatory containment requirements ............................................................................................................................. 7

6 Procedure for meeting the requirements of this document ................................................................................... 7

6.1 General ........................................................................................................................................................................................................... 7

6.2 Quality management system ....................................................................................................................................................... 8

6.3 Procedure .................................................................................................................................................................................................... 8

6.3.1 General...................................................................................................................................................................................... 8

6.3.2 Determination of permissible activity release rates ......................................................................... 9

6.3.3 Determination of standardized leakage rates......................................................................................10

6.3.4 Determination of permissible test leakage rates for each verification stage ...........10

6.3.5 Selection of appropriate test methods .......................................................................................................10

6.3.6 Performance of test and record of results .................. .............................................................................10

7 Determination of permissible activity release rates ...................................................................................................10

7.1 Step 1: List the radioactive contents, A ............................................................................................................................

i 10

7.2 Step 2: Determine the total releasable activity, RI ...............................................................................................

T 10

7.3 Step 3: Determine the maximum permissible activity release rates, R ............................................... 11

8 Determination of standardized leakage rates ....................................................................................................................11

8.1 General ........................................................................................................................................................................................................11

8.2 Step 4: Determine the activity release rate due to permeation, RP ........................................................ 12

8.3 Step 5: Determine the maximum permissible activity release rate due to leakage, RG ........ 12

8.4 Step 6: Determine the activity per unit volume of the containment system medium, C ...... 12

8.5 Step 7: Determine the maximum permissible volumetric leakage rate of the medium, L .. 12

8.6 Step 8: Determine the maximum permissible equivalent capillary leak diameter, D ............. 12

8.7 Step 9: Determine the permissible standardized leakage rate, Q ......................................................

SLR 13

9 Containment-system verification requirements ..............................................................................................................13

9.1 Containment-system verification stages .......................................................................................................................13

9.1.1 General...................................................................................................................................................................................13

9.1.2 Design verification ......................................................................................................................................................14

9.1.3 Fabrication verification ...........................................................................................................................................14

9.1.4 Preshipment verification .......................................................................................................................................14

9.1.5 Periodic verification ...................................................................................................................................................15

9.1.6 Maintenance verification .......................................................................................................................................15

9.2 Verification requirements ..........................................................................................................................................................15

9.2.1 General...................................................................................................................................................................................15

9.2.2 Step 10: Determine permissible test leakage rate for each verification

stage, Q , Q , Q Q Q and Q ...................................................................................................

TDA TDN TF, TS, TP TM 15

9.2.3 Step 11: Select appropriate test methods ...............................................................................................15

10 Leakage test procedure requirements .......................................................................................................................................16

10.1 General ........................................................................................................................................................................................................16

10.2 Step 12: Perform tests and record results ....................................................................................................................16

10.3 Test sensitivity ......................................................................................................................................................................................16

10.4 Test procedure requirements ..................................................................................................................................................16

10.4.1 General...................................................................................................................................................................................16

© ISO 2018 – All rights reserved iii
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SIST EN ISO 12807:2021
ISO 12807:2018(E)

10.4.2 Testing ....................................................................................................................................................................................16

Annex A (informative) Preferred leakage test methods ...............................................................................................................17

Annex B (informative) Methods of calculation........................................................................................................................................31

Annex C (informative) Conversion tables .....................................................................................................................................................36

Annex D (informative) Worked examples ....................................................................................................................................................37

Annex E (informative) Rationale ...........................................................................................................................................................................72

Bibliography .............................................................................................................................................................................................................................85

iv © ISO 2018 – All rights reserved
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SIST EN ISO 12807:2021
ISO 12807:2018(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: www .iso .org/iso/foreword .html.

This document was prepared by Technical Committee ISO/TC 85, Nuclear energy, nuclear technologies,

and radiological protection, Subcommittee SC 5, Nuclear installations, processes and technologies.

This second edition cancels and replaces the first edition (ISO 12807:1996), which has been technically

revised.

In this document, the word “shall” denotes a requirement; the word “should” denotes a recommendation;

and the word “may” denotes permission, neither a requirement nor a recommendation. Imperative

statements also denote requirements. To conform with this document, all operations shall be performed

in accordance with its requirements, but not necessarily with its recommendations.

The words “can”, “could” and “might” denote possibility rather than permission.

The word “will” denotes that an event is certain to occur rather than a requirement.

© ISO 2018 – All rights reserved v
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SIST EN ISO 12807:2021
ISO 12807:2018(E)
Introduction

The International Atomic Energy Agency (IAEA) Regulations for the Safe Transport of Radioactive

Material specify permitted release of radioactivity under normal and accident conditions of transport,

in terms of activity per unit of time, for Type B(U), Type B(M) and Type C packages used to transport

radioactive materials. Generally, it is not practical to measure activity release directly. The usual

method used is to relate activity release to non-radioactive fluid leakage, for which several leakages test

procedures are available. The appropriate procedure will depend on its sensitivity and its application

to a specific package.

The regulations specify permissible activity release for normal and accident conditions of transport.

These activity release limits can be expressed in maximum permissible activity release rates for the

radioactive material carried within a containment system.

In general, it is not feasible to demonstrate that the activity release limits are not exceeded by direct

measurement of activity release. In practice, the most common method to prove that a containment

system provides adequate containment is to carry out an equivalent gas leakage rate test.

vi © ISO 2018 – All rights reserved
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SIST EN ISO 12807:2021
INTERNATIONAL STANDARD ISO 12807:2018(E)
Safe transport of radioactive materials — Leakage testing
on packages
1 Scope

This document specifies gas leakage test criteria and test methods for demonstrating that packages

used to transport radioactive materials comply with the package containment requirements defined

in the International Atomic Energy Agency (IAEA) Regulations for the Safe Transport of Radioactive

Material for:
— design verification;
— fabrication verification;
— preshipment verification;
— periodic verification;
— maintenance verification.

This document describes a method for relating permissible activity release of the radioactive contents

carried within a containment system to equivalent gas leakage rates under specified test conditions.

This approach is called gas leakage test methodology. However, in this document it is recognized that

other methodologies might be acceptable, provided that they demonstrate that any release of the

radioactive contents will not exceed the regulatory requirements, and subject to agreement with the

competent authority.

This document provides both overall and detailed guidance on the complex relationships between an

equivalent gas leakage test and a permissible activity release rate. Whereas the overall guidance is

universally agreed upon, the use of the detailed guidance shall be agreed upon with the competent

authority during the Type B(U), Type B(M) or Type C packages certification process.

It should be noted that, for a given package, demonstration of compliance is not limited to a single

methodology.

While this document does not require particular gas leakage test procedures, it does present minimum

requirements for any test that is to be used. It is the responsibility of the package designer or consignor

to estimate or determine the maximum permissible release rate of radioactivity to the environment

and to select appropriate leakage test procedures that have adequate sensitivity.

This document pertains specifically to Type B(U), Type B(M) or Type C packages for which the

regulatory containment requirements are specified explicitly.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

International Atomic Energy Agency (IAEA). Regulations for the Safe Transport of Radioactive Material

3 Terms and definitions

For the purposes of this document, the terms and definitions given in the International Atomic Energy

Agency (IAEA), Regulations for the Safe Transport of Radioactive Material and the following apply.

© ISO 2018 – All rights reserved 1
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SIST EN ISO 12807:2021
ISO 12807:2018(E)

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

— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at https: //www .electropedia .org/
3.1
activity release rate

loss of radioactive contents per unit time through leaks or permeable walls of a containment system

3.2
blockage mechanism

mechanism by which radioactive material might be retained within a containment system due to

blockage of potential leakage paths by solid or liquid material
3.3
competent authority

any national or international authority designated or recognized as such for any purpose in connection

with the International Atomic Energy Agency (IAEA) Regulations for the Safe Transport of Radioactive

Material and other applicable regulations
3.4
containment system

assembly of components of the packaging intended to retain the radioactive material during transport

3.5
gas leakage test methodology

method of specifying a gas leakage test which relates permissible activity release rates of the radioactive

contents carried within a containment system to equivalent gas leakage rates under specified test

conditions
3.6
leak

any unwanted opening or openings through a containment system that could permit the escape of the

contents
3.7
leakage

transfer of a material from the containment system to the environment through a leak or leaks

Note 1 to entry: See also permeation (3.14).
3.8
leakage rate

quantity of solid particles, liquids or gases passing through leaks per unit time

Note 1 to entry: The term leakage rate can refer to the radioactive material (gas, liquid, solid or any mixture of

these) or to the test fluid.

Note 2 to entry: The dimensions of the rate of solid leakage are mass divided by time. The dimensions of the

rate of liquid leakage can be mass divided by time or volume divided by time. The dimensions of the rate of gas

leakage are the product of pressure and volume (this is a mass-like unit) divided by time at a known temperature.

3.9
leaktight

general term indicating that a containment system meets the required level of containment for

particular contents
Note 1 to entry: See Clause 8 in Annex E.
2 © ISO 2018 – All rights reserved
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SIST EN ISO 12807:2021
ISO 12807:2018(E)
3.10
medium

any fluid, which might or might not be radioactive itself, which could carry radioactive material through

a leak or leaks
3.11
molecular flow

flow of gas through a leak under conditions such that the mean free path is greater that the largest

dimension of a transverse section of the leak

Note 1 to entry: The rate of molecular flow depends on the partial pressure gradient.

3.12
package
packaging together with its radioactive contents as presented for transport
3.13
packaging
assembly of components necessary to enclose the radioactive contents completely
3.14
permeation

passage of a fluid through a solid permeable barrier (even if there are no leaks) by adsorption-diffusion-

desorption mechanisms

Note 1 to entry: Permeation should not be considered as a release of activity unless the fluid itself is radioactive.

In this document, permeation is applied only to gases.
3.15
permeation rate
quantity of gases passing through permeable walls per unit time
Note 1 to entry: The permeation rate depends on the partial pressure gradient.
3.16
qualitative

refers to leakage test procedures which detect the presence of a leak but do not measure leakage rate or

total leakage
3.17
quantitative

leakage test procedures which measure total leakage rate(s) from a containment system or from

parts of it
3.18 Sensitivity
3.18.1
sensitivity of a leakage detector

minimum usable response of the detector to tracer fluid leakage, that is, the leakage rate that will

produce a repeatable change in the detector reading
3.18.2
sensitivity of a leakage test procedure
minimum detectable leakage rate that the test procedure is capable of detecting
© ISO 2018 – All rights reserved 3
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SIST EN ISO 12807:2021
ISO 12807:2018(E)
3.19
standardized leakage rate
SLR

leakage rate, evaluated under known conditions, normalized to the flow of dry air at reference conditions

of upstream pressure 1,013 × 10 Pa, downstream pressure 0,0 Pa and temperature of 298 K (25 °C)

3 −1

Note 1 to entry: The units for standardized leakage rate are written as Pa·m ·s SLR.

3.20
standardized helium leakage rate
SHeLR

helium leakage rate, evaluated under known conditions, normalized to the flow of dry helium at

reference conditions of upstream pressure 1,013 × 10 Pa, downstream pressure 0,0 Pa and temperature

of 298 K (25 °C)
3 −1

Note 1 to entry: The units for standardized helium leakage rate are written as Pa·m ·s (SHeLR).

3.21
test gas or tracer gas
gas that is used to detect leakage or measure leakage rates
3.22
viscous flow

continuous flow of gas through a leak under conditions such that the mean free path is very small in

comparison with the smallest dimension of a transverse section of the leak

Note 1 to entry: This flow may be either laminar or turbulent. Viscous flow depends upon total pressure gradient.

4 Symbols and units
The following symbols and units are used in this document.
Symbol Definition Unit
A Activity of radionuclide i Bq

A Quantity (activity) of radioactive material, other than special-form radioac- Bq

tive material, as defined in the applicable documents listed in the Interna-
tional Atomic Energy Agency (IAEA) Regulations for the Safe Transport of
Radioactive Material
A A value of radionuclide i Bq
2i 2
a Capillary length/leakage hole length m

C Average activity per unit volume; the symbol is used to simplify Figure 1 and Bq·m

represents the use of either C or C
A N
C Average activity per unit volume of the medium that could escape from the Bq·m
containment system under accident conditions of transport
C Average activity per unit volume of the medium that could escape from the Bq·m
containment system under normal conditions of transport
D Capillary diameter/leakage hole diameter m
D Maximum permissible diameter; the symbol is used to simplify Figure 1 and m
represents the use of either D or D
A N
D Maximum permissible equivalent capillary leak diameter under accident m
conditions of transport
D Bubble diameter m
D Maximum permissible equivalent capillary leak diameter under normal m
conditions of transport
FC Release fraction of radionuclide i from th
...

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