SIST EN ISO 16647:2021

SLOVENSKI STANDARD
oSIST prEN ISO 16647:2021
01-junij-2021
Jedrski objekti - Merila za načrtovanje in delovanje zadrževalnih sistemov za
jedrska delovišča in jedrske naprave, ki so v razgradnji (ISO 16647:2018)
Nuclear facilities - Criteria for design and operation of confinement systems for nuclear
worksite and for nuclear installations under decommissioning (ISO 16647:2018)
Kerntechnische Anlagen - Kriterien für die Planung und den Betrieb von
Rückhaltesystemen und Lüftungssysteme für kurzzeitige Arbeitsplätze und für
kerntechnische Anlagen, die rückgebaut werden (ISO 16647:2018)
Installations nucléaires - Critères pour la conception et l'exploitation des systèmes de
confinement des chantiers nucléaires et des installations nucléaires en démantèlement
(ISO 16647:2018)
Ta slovenski standard je istoveten z: prEN ISO 16647
ICS:
27.120.20 Jedrske elektrarne. Varnost Nuclear power plants. Safety
oSIST prEN ISO 16647:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 16647:2021
INTERNATIONAL ISO
STANDARD 16647
First edition
2018-09
Nuclear facilities — Criteria for design
and operation of confinement systems
for nuclear worksite and for nuclear
installations under decommissioning
Installations nucléaires — Critères pour la conception et
l'exploitation des systèmes de confinement des chantiers nucléaires et
des installations nucléaires en démantèlement
Reference number
ISO 16647:2018(E)
©
ISO 2018

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oSIST prEN ISO 16647:2021
ISO 16647:2018(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
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Email: copyright@iso.org
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Published in Switzerland
ii © ISO 2018 – All rights reserved

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Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Functions ensured by the confinement . 4
5 Principles for radioactive substances confinement. 4
5.1 General principles . 4
5.2 Risk assessment procedure . 5
5.3 General requirements . 6
5.4 Confinement system . 6
5.4.1 General. 6
5.4.2 Case of a worksite containment located in an existing "confinement system" . 7
5.4.3 Case of a worksite containment located beyond any "confinement system" . 7
5.4.4 Summary of different natures and levels of confinement . 7
5.5 Static containment . 8
5.6 Dynamic confinement . 9
5.7 Air clean-up modalities before release . 9
6 Methodology and recommendation for confinement design . 9
6.1 Classification of the installation into working areas . 9
6.1.1 General. 9
6.1.2 Confinement area classification . 9
6.1.3 Other classifications for areas .10
6.2 Static containment design .10
6.3 Dynamic confinement design .11
6.4 Integrated confinement design (static-dynamic confinement) .12
6.5 Airtight bag and ventilated airtight bag .15
6.6 Protection against weather: sun, rain, wind, snow and extreme temperatures .16
6.7 Air-change rate .16
6.8 Air inlet filtration and air-transfer between confinement system .17
6.9 Air clean-up system design .18
6.9.1 Areas not classified under radiological dispersal.18
6.9.2 Areas classified under the radiological release .18
6.10 Connection to any existing ventilation networks .19
6.10.1 General.19
6.10.2 Worksite containment located in a building, room or enclosure equipped
with a nuclear ventilation .19
6.10.3 Worksite containment beyond any nuclear ventilation .20
6.10.4 Additional recommendations .21
6.11 Recommended ventilation configuration as function of confinement class .22
6.12 Worksite containment usually used .22
7 Recommendations concerning commissioning, monitoring and operation
of containment .23
7.1 General .23
7.2 Pre-commissioning inspection .23
7.3 Monitoring of the confinement .24
7.3.1 General.24
7.3.2 Monitoring of static containment .24
7.3.3 Monitoring of dynamic confinement .24
7.3.4 Monitoring of purification systems .25
7.3.5 Other monitoring .26
7.4 Containment operation .26
7.5 Containment disassembly .26
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8 Considerations about other risks than radiological risks related to confinement .27
Annex A (informative) Example of confinements classification and recommendations on
associated equipment .28
Annex B (informative) Examples for the selection of materials constituting worksite
containment .31
Annex C (informative) Practical guidance on worksite containment arrangements .32
Bibliography .35
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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
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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 ISO/TC 85, Nuclear energy, nuclear technologies, and radiological
protection, SC 2, Radiological protection.
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oSIST prEN ISO 16647:2021
INTERNATIONAL STANDARD ISO 16647:2018(E)
Nuclear facilities — Criteria for design and operation of
confinement systems for nuclear worksite and for nuclear
installations under decommissioning
1 Scope
This document specifies the requirements applicable to the design and use of airborne confinement
systems that ensure safety and radioprotection functions in nuclear worksites and in nuclear installations
under decommissioning to protect from radioactive contamination produced: aerosol or gas.
The purpose of confinement systems is to protect the workers, members of the public and environment
against the spread of radioactive contamination resulting from operations in nuclear worksites and
from nuclear installations under decommissioning.
The confinement of nuclear worksites and of nuclear installations under decommissioning is
characterized by the temporary and evolving (dynamic) nature of the operations to be performed.
These operations often take place in area not specifically designed for this purpose.
This document applies to maintenance or upgrades at worksites which fit the above definition.
NOTE The requirements for the design and use of ventilation and confinement systems and for liquid
confinement in nuclear reactors or in nuclear installations other than nuclear worksites and nuclear installations
under decommissioning are developed in other ISO standards.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 16170, In situ test methods for high efficiency filter systems in industrial facilities
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:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
climatic shelter
shelter whose function is to provide suitable protection against the weather (sun, rain, wind, snow and
extreme temperatures), usually structurally separated from radiological containment
3.2
aerosol
solid particles and liquid droplets of all dimensions in suspension in a gaseous fluid
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3.3
barrier
structural element, which defines the physical limits of a volume with a particular radiological
environment and which prevents or limits releases of radioactive substances from this volume
EXAMPLE Containment enclosure, shielded cell, filters.
3.4
discharge stack
duct (usually vertical) at the termination of a system, from which the air is discharged to the atmosphere
3.5
air conditioning
arrangement allowing the sustainment of a controlled atmosphere (temperature, humidity, pressure,
dust levels, gas content, etc.) in a closed volume
3.6
confinement
arrangement allowing users to maintain separate environments inside and outside an enclosure,
blocking the movement between them, of process materials and substances resulting from physical
and chemical reactions which are potentially harmful to workers, the external environment, or to the
handled products
Note 1 to entry: The word “confinement” is used in several IAEA documents to mean the function of confining
radioactive or toxic products whereas “containment” is used to mean the physical barrier that achieves the
objective of confinement, i.e. a confined area.
3.7
worksite containment
specific containment implemented to cover the temporary and evolving nature of worksite activities
3.8
dynamic confinement
action allowing, by maintaining a preferential air flow circulation, to limit back-flow between two areas
or between the inside and outside of an enclosure, in order to prevent radioactive substances being
released from a given physical volume
3.9
contamination
presence of radioactive substances on or in a material or a human body or any place where they are
undesirable or could be harmful
3.10
containment enclosure
enclosure designed to prevent either the leakage of products contained in the pertinent internal
environment into the external environment, or the penetration of substances from the external
environment into the internal environment, or both simultaneously
3.11
gas cleaning
action of decreasing the content of undesirable constituents in a fluid
Note 1 to entry: Gas cleaning is sometimes called "scrubbing".
Note 2 to entry: Aerosol filtration and iodine trapping are examples of gas cleaning.
3.12
filter
device intended to trap particles suspended in gases and fluids or to trap gases themselves
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3.13
high efficiency particle air filter
HEPA filter
aeorosol filter that corresponds to the classes H35, H40 or H45 according to ISO 29463-1
3.14
last filtration stage
LFS
last filtering stage implemented on the dynamic confinement release network protecting the
environment
EXAMPLE HEPA filters for aerosols, iodine filters, etc.
3.15
Derived air concentration
DAC
3
amount of contamination in air, which, if 2 200 m is inhaled, would result in the annual limit of
intake (ALI)
3
Note 1 to entry: DAC is defined in ICRP 103 and expressed in Bq/m .
Note 2 to entry: The ALI is calculated using reference conversion factors given by ICRP (International Commission
for Radiological Protection) for each radionuclide (ICRP 119).
3.16
airtight bag
ventilated airtight bag
flexible containment used to establish an enclosure around a contaminated item, allowing personnel to
accomplish works or manipulations potentially via gloved sleeves without contacting the contaminated
environment
Note 1 to entry: The airtight bag may include inlet and extract ventilation in order to achieve an air velocity in
leakage points or negative pressure within the containment.
3.17
spark arrestor
device fitted upstream of the main filters to minimize transport of particles and the deterioration of
main filters, by capture of incandescent large particles
3.18
prefilter
filter fitted upstream of the main air filters to minimize the dust burden on the latter, by removal of
large particles
3.19
negative pressure
depression
pressure difference between the pressure of a given volume, which is maintained lower than the
pressure in a reference volume or the external ambient pressure
3.20
confinement system
system constituted by a coherent set of physical barriers and/or dynamic systems intended to confine
radioactive substances
3.21
ventilation system
totality of network components such as ducts, fans, filter units and other equipment, that ensures
ventilation and gas cleaning functions
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3.22
air-change rate
ratio between the ventilation air flow rate of a containment enclosure or a compartment and the volume
of this containment enclosure or compartment, during normal operating conditions
3.23
ventilation
organization of air flow patterns within an installation
4 Functions ensured by the confinement
The confinement of nuclear worksite and nuclear installations under decommissioning (sometimes
in complement with the existing confinement of the installation) enables the improved safety of the
workers, members of the public and provides protection of the environment. It plays the role of:
— Safety and radioprotection, by contributing to limit the contamination impact on the workers,
members of the public and the environment.
— Protection of equipment and rooms, maintaining the level of cleanliness to avoid any radiological
releases of contamination.
Confinement system ensures the following main functions:
— Confinement, by acting in a static and/or dynamic manner. The role of this function is to control
the release and spread of radioactive products, in aerosol or gas form, in environment, and to
protect workers, in particular those that do not have respiratory protection from existing volume
radioactivity or volume radioactivity generated by activities.
— Cleaning the atmosphere of the enclosure or room, by renewing the volumes of air within it, in order
to minimise the risks associated with the corresponding atmosphere (for example, the elimination
of any gas that can lead to an explosion hazard, fume gas evacuation, etc.).
— Purification (or gas cleaning) by conveying the collected gases including any dust, aerosols and
volatile components, to defined and controlled points for collection, processing and elimination if
possible (by using filters, traps, etc.).
— Radiological cleanliness maintaining the level of the atmospheric and surface contamination of
equipment and rooms, as low as possible
The dynamic confinement system may also contribute to the following functions:
— Surveillance of the releases, in particular when the static containment faces the environment by
orientating the airflows to the contamination sensors to the exhaust points.
— Conditioning of the atmosphere of considered volumes to ensure ambient conditions continually
compatible with the proper functioning of the equipment.
5 Principles for radioactive substances confinement
5.1 General principles
Confinement systems shall ensure the safety and radioprotection functions defined in Clause 4, in all
normal operating conditions of nuclear worksites and nuclear installations under decommissioning.
They shall also ensure that these functions continue during abnormal operating conditions, or accident
situations that are to be defined case by case depending on the safety analysis.
Before beginning any confinement design, a risk assessment shall be made so that actual targets are
adequately defined. 5.2 provides an outline of the risk assessment process.
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5.2 Risk assessment procedure
The design of an appropriate confinement system requires preliminary analysis, taking into account:
— radiological hazards generated by materials and operations leading to the need to confine the rooms
or work areas where hazardous substances are handled, including:
— permissible levels of surface or airborne contamination inside the room or rooms where are
contained confined enclosures;
— requirements for airborne contamination monitoring;
— verification of discharge authorization limits in respect of actual discharges through existing
ventilation systems or ventilation systems to be set up;
— risks associated with the facility to which the confined enclosures and ventilation systems can be
exposed and that can be considered plausible on the installation (e.g. load drop, fire, flood, external
explosion, earthquakes, wind and extreme temperatures, etc.);
— human activities deployed nearby facilities (collocated operations);
— possible temporary unavailability of fluids or energy necessary for the proper functioning of the
confinement system (electricity, compressed air, neutral gases, cooling water, etc.);
— non-radiological hazards associated with equipment and operations implemented in confined
enclosures (e.g. sudden break of containment due to mechanical failure, sudden change in pressure,
over pressure risks, explosion, fire, corrosion, condensation, load drop), which consequences may
be resuspension of radioactivity. As an example, when the worksite confinement is used in the fire
safety demonstration, special analyses are needed for cases where fire extinguishers are likely to
create a breach in the confinement, e.g. by pressurizing the static confinement because of their
potential impact on dynamic confinement or for glove boxes for which water cannot be used when
they are criticality risks.
For each consideration, a risk assessment is to be carried out using the safety analysis methodology
where the risk is defined as the combination of the consequences of the event and its estimated
frequency. This may consist of a deterministic approach, based on incidental or accidental conservative
situations.
Other factors to consider in the design of confinement systems are:
— to reduce the amount of waste produced and radioactive release (liquid and gaseous) to a level as
low as reasonably achievable, for the protection of the environment;
— to minimize the level of contamination in the rooms or work areas as far as reasonably achievable,
in particular by implementing dynamic confinement as close as possible to the source;
— the impact on the existing installation of modifications of ventilation network, enclosure,
containment enclosure layout, etc.;
— physical and radiological state of the existing installation (e.g. for static confinement, cable, drains);
— incidental or accidental situations;
— appropriate work conditions that should be provided to workers;
— robustness of confinement system (e.g. fan redundancy), if considering worksite containment with
high permanent volumic activity.
The risk assessment procedure is needed to define the requirements for the worksite confinement
provisions and to give appropriate health physics coverage to the workers prior to the start of the
activities: e.g. process provisions/rinsing/cleaning of systems to be removed or decommissioned,
additional local shielding, access control.
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Performing such adequate analysis optimizes confinement provisions.
There are several safety topics to be considered in the analysis, and in particular ALARA (as low as
reasonably achievable) principle for worker radiations exposure, waste, etc.
5.3 General requirements
The basic principle with regard to the prevention of the spread of the radioactive material is:
— in normal situations, to limit the release of radioactive material outside the facility to levels that are
as low as reasonably achievable, through dedicated monitored pathways, but also to reduce the level
of contamination inside the nuclear worksite or the nuclear installation under decommissioning;
— in accidental situations, to limit the radiological consequences for the environment and the workers
to acceptable levels.
The application of this principle leads to the provision of different confinement systems between the
environment and the radioactive substances. Each confinement system and the associated devices
are designed to suit the risks they are intended to control. The goal is to maintain, in any case, the
functionality of at least one stage of effective containment and filtration between the contaminated
areas
...