EN ISO 18557:2020

SLOVENSKI STANDARD
01-maj-2020
Načela za opisovanje lastnosti zemljin, zgradb in infrastruktur, kontaminiranih z
radionuklidi, za potrebe sanacije (ISO 18557:2017)
Characterisation principles for soils, buildings and infrastructures contaminated by
radionuclides for remediation purposes (ISO 18557:2017)
Charakterisierungsgrundsätze für mit Radionukliden kontaminierte Böden, Gebäude und
Infrastrukturen zu Sanierungszwecken (ISO 18557:2017)
Principes de caractérisation des sols, bâtiments et infrastructures contaminés par des
radionucléides, à des fins de réhabilitation (ISO 18557:2017)
Ta slovenski standard je istoveten z: EN ISO 18557:2020
ICS:
13.020.40 Onesnaževanje, nadzor nad Pollution, pollution control
onesnaževanjem in and conservation
ohranjanje
13.280 Varstvo pred sevanjem Radiation protection
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 18557
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2020
EUROPÄISCHE NORM
ICS 13.020.40; 27.120.30
English Version
Characterisation principles for soils, buildings and
infrastructures contaminated by radionuclides for
remediation purposes (ISO 18557:2017)
Principes de caractérisation des sols, bâtiments et Charakterisierungsgrundsätze für mit Radionukliden
infrastructures contaminés par des radionucléides, à kontaminierte Böden, Gebäude und Infrastrukturen zu
des fins de réhabilitation (ISO 18557:2017) Sanierungszwecken (ISO 18557:2017)
This European Standard was approved by CEN on 6 January 2020.

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
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 18557:2020 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO 18557:2017 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 18557:2020 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 2020, and conflicting national standards shall
be withdrawn at the latest by August 2020.
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 18557:2017 has been approved by CEN as EN ISO 18557:2020 without any modification.

INTERNATIONAL ISO
STANDARD 18557
First edition
2017-09
Characterisation principles for
soils, buildings and infrastructures
contaminated by radionuclides for
remediation purposes
Principes de caractérisation des sols, bâtiments et infrastructures
contaminés par des radionucléides, à des fins de réhabilitation
Reference number
ISO 18557:2017(E)
©
ISO 2017
ISO 18557:2017(E)
© 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

ISO 18557:2017(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Strategy applied to the remediation of contaminated sites . 6
4.1 Principle . 6
4.2 Characterization and remediation objectives . 8
4.3 Historical analysis . 9
4.4 Documents . 9
4.5 Interviews . 9
4.6 Functional analysis .10
4.7 Preliminary characterization .10
4.8 Definition of the zones of interest and contamination tracers .10
4.9 Surface and/or volumetric characterization program .11
4.10 Data processing and contamination assessment .12
4.11 Conf ormity of the results to the characterization objectives .13
4.12 Remediation programme .13
4.13 Final characterization .15
5 Surface characterization programme .16
5.1 Principle .16
5.2 Non-destructive analysis .18
5.2.1 Characterization programme: Determination of the sampling design and
the number of data points .18
5.2.2 Implementation .19
5.3 Destructive analysis .19
5.3.1 Characterization programme .19
5.3.2 Implementation and laboratory analyses .19
5.4 Preliminary consolidation .20
5.5 Data processing .20
5.5.1 Spatial structure of the phenomenon .20
5.5.2 Data processing in the case of spatially structured contaminations .20
5.5.3 Result mapping in the case of spatially structured contaminations .20
5.5.4 Statistical processing in the case of non-structured contaminations .20
5.6 Conf ormity of the results with the characterization objective .21
5.7 Surface characterization file .21
6 Volumetric characterization programme .21
6.1 Principle .21
6.2 Volumetric investigations .24
6.2.1 Characterization programme .24
6.2.2 Implementation and laboratory analyses .24
6.3 Preliminary consolidation .24
6.4 Volumetric Data processing .25
6.4.1 Case of structured contaminations .25
6.4.2 Case of non-structured contaminations .25
6.5 Compatibility of the results with the objectives .25
6.6 Volumetric characterization file .25
7 Final characterization programme .27
7.1 Principle .27
7.2 Final characterization programme .27
7.3 Processing the final characterization results .28
7.4 Final characterization file .29
ISO 18557:2017(E)
8 Final report .29
Annex A (informative) Geostatistical data processing and examples of good practices .31
Bibliography .35
iv © ISO 2017 – All rights reserved

ISO 18557:2017(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: www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 85, Nuclear energy, nuclear technologies,
and radiological protection, Sub-committee SC 5, Nuclear fuel cycle.
ISO 18557:2017(E)
Introduction
The remit of WG 13 covers all aspects of the decommissioning phase, and thus it interfaces with other
Sub-Committees and Working Groups whose work intersects with this phase.
Figure 1 below indicates some of the topics that could be included in SC 5 and/or WG 13. It provides a
view of how the scope of this ISO Standard links with both generic and more detailed topics.
This document contains both guidance and references to documents which may be useful in relation
to this work area. Read in conjunction with the supporting references, it gives a generic approach
to the topic. It also may have connections with many other blocks across the whole diagram (e.g.
Decommissioning strategy, Waste Management, Site remediation, Dismantling/Demolition, Cost issues,
Safety).
Moreover, it was not intended to establish this document as a stand-alone document. When a member
country already has national tools in this field (e.g. regulatory requirements, national standards), these
requirements and national standards are applicable in conjunction with this document.
Figure 1 — Indicative chart of the topics included in WG 13, showing how this document is
linked to other topics
This work stream structure can be used to clarify the scope of WG publications and to ensure that areas
of joint interest between ISO teams and working groups are coordinated. The ISO shadow committee for
a member body identifies proposals for further work and, if appropriate, submits them to the Working
Group for international consideration as potential new work items. Figure 1 can be a useful prompt
in this process. This document is part of an overall decommissioning and environmental remediation
strategy including, for example, the monitoring and/or remediation of groundwater which might be
addressed in a new work item.
vi © ISO 2017 – All rights reserved

ISO 18557:2017(E)
Since the discovery of radioactivity at the end of the 19th century, numerous laboratories and facilities
have dealt with radioactive substances (notably radium). In addition, the development and considerable
expansion of the nuclear industry, both civilian and defence, has generated many nuclear facilities built
since the 1940s, resulting today in legacy sites.
More recently, nuclear operators and state organisations have intensively undertaken the dismantling
and remediation of shutdown nuclear facilities. Remediation projects also concern former mining
sites, other legacy sites and industrial sites having produced NORM (Naturally Occurring Radioactive
Material) and TENORM (Technologically Enhanced NORM) waste, where the main issue is the large
volume of waste involved. The aim is primarily to demonstrate that the entire nuclear cycle is well
managed. A large number of issues need to be considered:
— The nuclear regulatory framework did not exist at the beginning and it has evolved over time
(release procedures, health and safety, environmental considerations…). In addition, there is more
and more stakeholder involvement today, and this needs to be considered at the early stages of any
project.
— The availability of waste management facilities and disposal sites varies between countries and
through time. The classification based on activity levels: e.g. very low level waste (VLLW), low level
waste (LLW), intermediate level waste (ILW), high level waste (HLW) and nuclide half-lives (short-
lived or long-lived radionuclides) impacts remediation projects. These factors sometimes result in
the partial clean-up of sites, due to the absence of a final solution for waste disposal. Waste may also
have had to be temporarily stored on site for economic reasons.
— Remediation costs and schedules are optimized and rationalized using a graded approach, as these
projects are generally expensive and time consuming. They also need to be securely funded and
planned.
— In order to optimize waste categories, volumes and costs, characterization is a crucial issue enabling
the best knowledge of the radiological state of the site (soils, buildings and infrastructures) to be
obtained before making project decisions.
Lessons learned from the first sites to be remediated have demonstrated that poor characterization
(based on incomplete historical information and too limited a number of data points or samples)
strongly impacts the success of a remediation project, with inappropriate choices having been made
(over-estimation of volumes and over-categorization of waste, unexpected contamination).
As a consequence, it is now recognized that accurate characterization is the key to successful
dismantling and remediation projects. There are many characterization steps necessary throughout a
project, each with specific objectives.
The main potential improvement concerns the sampling effort, sample representativeness and
assessment of activity levels assessments. Combined with data analysis and processing, all the
uncertainties involved are combined to deliver a result with a corresponding confidence interval.
Therefore the characterization strategy and programme should be set well before the actual
measurements, to ensure efficiency.
The preparation of any nuclear facility’s remediation programme requires knowledge of its operational
history. This covers the entire period from design, licensing and through to final shutdown, in order
to establish the nature and location of potential or known radioactive contamination, together with
possible associated chemical products, with the appropriate accuracy. The overall remediation strategy
requires an estimation of the quantity and the volume of waste to be produced, and an assessment of its
level of contamination. This enables appropriate optimized waste management.
In addition, a final characterization is compulsory for sites to be released and/or re-used in order to
demonstrate compliance with remediation objectives (clearance levels, if any, or a release threshold set
by, or agreed with, the regulatory body).
This document outlines the principles of characterization for remediation purposes of soils, buildings
and infrastructures contaminated by radionuclides and possible associated chemical pollutants.
ISO 18557:2017(E)
As the preparation of a sampling plan is an iterative process, decision-taking steps will be defined
throughout this document taking into account constraints imposed by operations, budgets and
regulations, while respecting the ALARA and ALARP principles.
The application of this methodology will aid the user to obtain the information necessary for compiling
the files associated with remediation operations, as required by the regulatory authorities. It is
applicable to each of the steps necessary for the remediation of sites, depending on the objectives
(release into the public domain, re-use). It can enable an assessment to be established for contaminated
soils, or in preparing to carry out post-remediation checks (even including the facility’s civil engineering
structures), in order to confirm that the remediation objectives have been met.
With regards to the recommendations of the International Atomic Energy Agency (IAEA), a graded
approach should be considered for the characterization of soils, buildings and infrastructures
for remediation purposes. The characterization strategy, programme and planning should be
commensurate with the complexity of the remediation problem and with the established end state. A
graded approach can limit occupational exposure for workers, as well as saving time and money [ref.
IAEA = DeSa project (Evaluation and Demonstration of Safety for Decommissioning of Facilities Using
Radioactive Material)].
viii © ISO 2017 – All rights reserved

INTERNATIONAL STANDARD ISO 18557:2017(E)
Characterisation principles for soils, buildings and
infrastructures contaminated by radionuclides for
remediation purposes
1 Scope
This document presents guidelines for sampling strategies and characterization processes to assess
the contamination of soils, buildings and infrastructures, prior to remediation and/or to check that
the remediation objectives have been met (final release surveys). The principles presented need to be
appropriately graded as regards the specific situations concerned (size, level of contamination…). It can
be used in conjunction with each country’s key documentation.
This document deals with characterization in relation to site remediation. It applies to sites
contaminated after normal operation of older nuclear facilities. It could also apply to site remediation
after a major accident, and in this case the input data will be linked to the accident involved.
The document complements existing standards, notably concerning sampling, sample preservation and
their transport, treatment and laboratory measurements, but also those related to in situ chemical and
radiological measurements. References in the Bibliography contain links to appropriate documentation
and techniques as required by individual member countries.
The document does not apply to the following issues: execution of clean-up works, sampling and
characterization of waste (conditioned or unconditioned) or to waste packages.
It does not apply to groundwater characterization (saturated zone).
Given the case-by-case nature of site remediation and decommissioning, the principles and guidance
communicated in this document are intended as general guidance only, not prescriptive requirements.
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
characterization
determination of the nature, concentration and spatial extent of radiological and chemical contents
present in a specified place
Note 1 to entry: See also radiological and chemical survey.
ISO 18557:2017(E)
3.2
clean-up work
actions taken to reduce the exposure to radiological and chemical substances from existing
contamination through actions applied to the contamination itself (the source) or to the exposure
pathways to humans and the environment
Note 1 to entry: See also remediation (3.22).
3.3
clearance level
release threshold
value, or a set of values, established by a regulatory body and expressed in terms of activity concentration
and/or total activity, at or below which a source of radiation may be released from regulatory control
3.4
contaminant
radioactive or chemical substance or agent present in a medium which due to its properties, amount or
concentration may have impacts on the environment and human health
3.5
contamination
presence of radioactive or chemical substance or agent in any medium where it is not desired, and which
due to its properties, amount or concentration may have impacts on the environment and human health
3.6
cost-benefit analysis
decision aiding tool using a systematic evaluation of the positive effects (benefits) and negative effects
(disbenefits) of undertaking an action, integrating technical, time-schedule, management, financial,
societal, environmental issues.
3.7
data quality assessment
DQA
process performed once the collected data have been properly verified and validated
Note 1 to entry: In DQA, assessment means evaluation of quality of data that is meaningful only when it relates to
the intended use of the data.
3.8
data quality objective
DQO
process used to establish performance or acceptance criteria, which serve as the basis for designing a
plan for collecting data of sufficient quality and quantity to support the goals of a study
3.9
destructive analysis
DA
analysis of radioactive and chemical materials using methods which involve the destruction of a sample,
e.g. chemical and radiochemical analysis, ICP-MS, alpha spectrometry
3.10
difficult to measure radionuclides DTM
nuclides that cannot be easily measured through their gamma radiation or beta emissions; usually
comprise alpha-emitting nuclides without strong gamma lines or pure beta emitters
3 14 36 90 99 129 238
Note 1 to entry: Examples include H, C, Cl, Sr, Tc, I, Pu.
2 © ISO 2017 – All rights reserved

ISO 18557:2017(E)
3.11
easy to measure radionuclides
ETM
gamma emitting nuclides whose radioactivity can be readily measured directly by non-destructive
analysis means
3.12
fingerprint
nuclide vector
used to infer and quantify the presence of other key nuclides
Note 1 to entry: Applying correlation factors enables estimations of difficult to measure nuclides (3.10).
Note 2 to entry: It is a method which involves measurements of easy to measure radionuclides (3.11) (usually
137 60
gamma emitters, e.g. Cs, Co) to quantify difficult to measure nuclides (3.10).
3.13
geostatistics
statistical methodology based on the use of spatial correlations between couples of measured values,
which produces interpolation maps by the kriging technique
Note 1 to entry: The added value of geostatistics lies in the quantification of the result uncertainty and its more
advanced techniques (non linear, non stationary, multivariate…).
3.14
graded approach
application of safety requirements that is commensurate with the characteristics of the practice or
source and with the magnitude and likelihood of the exposures
Note 1 to entry: The use of a graded approach is intended to ensure that the necessary levels of analysis,
documentation and actions are commensurate with, for example, the magnitudes of any radiological hazards
and non-radiological hazards, the nature and the particular characteristics of a facility or site, and the stage in its
lifetime.
3.15
health impact assessment
combination of procedures, methods and tools by which a policy, programme or project may be judged
as to its potential effects on the health of a population, and the distribution of those effects within the
population
3.16
infrastructures
all ancillary equipment and facilities providing necessary support to the operation of a nuclear facility
or site: e.g. sewage network, roads. but also heavy equipment which might be disposed of as waste or
re-used after clean-up, such as bridge and portal cranes
3.17
in situ measurement
field measurement
measurement where the detection instrument is taken to the material: it is a non-destructive
measurement
3.18
judgement assessment
measurements performed at locations selected using expert judgment based for instance on unusual
appearance, location relative to known contaminated areas, high potential for residual radioactivity,
general supplemental information.
ISO 18557:2017(E)
3.19
mapping
representation of 2D or 3D objects
Note 1 to entry: Background layers consist of aerial or satellite images as well as vectorial maps. Measured data
are represented in the form of a map (points, colourscale, size, symbol…). It also integrates 2D and 3D grid results
(e.g. isocontours, slices, selection).
3.20
non-destructive analysis
NDA
number of analytical techniques that allow measurement of specific properties without physical
destruction of the media/item
Note 1 to entry: Generally used for in situ measurements.
3.21
radionuclide
RN
nucleus (of an atom) that possesses properties of spontaneous disintegration (radioactivity)
Note 1 to entry: Nuclei are distinguished by their mass number and atomic number.
3.22
remediation
measures taken for contaminant removal, containment or monitored non-intervention at a
contaminated site to reduce exposure to radiation, and for improvement in the environmental and/or
economic value of the contaminated site
Note 1 to entry: to entry: Remediation of a site does not necessarily imply a restoration of the site to pristine
condition.
3.23
remediation objectives
generic term for any objective, including those related to technical (for example residual contamination
concentrations, engineering performance), administrative and legal requirements
Note 1 to entry: to entry: The future site end-use assumption forms the basis of remediation objectives and is
used in developing the strategy for the decommissioning and remediation activities.
3.24
sample
set of individual physical portions or measurements drawn from a population whose properties are
studied to gain information about the entire population
Note 1 to entry: to entry: The manner the sample is selected should be described in the sampling plan (3.27).
3.25
laboratory sample
sample intended for laboratory inspection or analysis
Note 1 to entry: When the laboratory sample is further prepared (reduced) by subdividing, mixing, grinding, or
by combinations of these operations, the result is the test sample. When no preparation of the laboratory sample
is required, the laboratory sample is the test sample. A test portion is removed from the test sample for the
performance of the test or for analysis.
Note 2 to entry: The laboratory sample is the final sample from the point of view of sample collection but it is the
Initial sample from the point of view of the laboratory.
Note 3 to entry: Several laboratory samples may be prepared and sent to different laboratories or to the same
laboratory for different purposes.
4 © ISO 2017 – All rights reserved

ISO 18557:2017(E)
3.26
sampling
act of taking or constituting (and preparing) a sample, in the aim of investigating a whole population
Note 1 to entry: For the purpose of soil investigation, “sampling” also relates to the selection of locations for in
situ testing carried out in the field without removal of material.
3.27
sampling plan
detailed outline of which measurements will be taken, typically detailing at what times, on which
material, in what manner, and by whom
Note 1 to entry: Sampling plans are designed in such a way that the resulting data will contain a representative
sample of the parameters of interest and enable all questions, as stated in the goals, to be answered.
Note 2 to entry: The steps involved in developing a sampling plan are typically:
a) Identify the parameters to be measured, the range of possible values, and the required resolution.
b) Design a sampling scheme that details how and when samples will be taken.
c) Select sample sizes.
d) Design data storage formats.
e) Assign roles and responsibilities.
Note 3 to entry: This includes which surveys will be done, which samples will be taken, and how they will be
collected, prepared and measured (e.g. sampling point, time of collection, depth of sampling, and other variables
necessary to carry out a measurement of a specific sampling location in time and space).
Note 4 to entry: The plan may specify, for example, that the sampling is systematic and in two stages. In
combination with the specification of the type of sampling, the sampling plan in this example also may specify
the number of increments to be taken from a lot, the number of composite samples (or gross samples) per lot, the
number of test samples per composite sample, and the number of measurements/tests per test sample.
3.28
probabilistic sampling
sampling conducted according to the statistical principles of sampling, to ensure that each particle or
element in the population submitted to sampling has an equal chance of being part of the sample
Note 1 to entry: Probabilistic sampling results in boundary conditions for the type of sampling equipment used,
the method of sampling (where, when, how) and the minimum size of increments and (composite) samples.
3.29
site
any installation, facility, or discrete physically separate parcel of land, or any building or infrastructure
or portion thereof, that is being considered for survey and investigation and if necessary, remediation
Note 1 to entry: It includes soils, buildings and infrastructures (excluding surface and groundwater).
3.30
radiological survey
chemical survey
type of survey that includes facility or site sampling, monitoring, and analysis activities to determine
the extent and nature of contamination (3.5)
Note 1 to entry: Characterization surveys provide the basis for acquiring necessary technical information to
develop, analyse, and select appropriate cleanup techniques.
Note 2 to entry: See also characterization (3.1).
ISO 18557:2017(E)
3.31
variogram
semi-variogram
measure of spatial variation of a variable
3.32
zone of interest
area of interest
area where contamination (3.5) is suspected after historical analysis, functional analysis or preliminary
characterization (3.1)
4 Strategy applied to the remediation of contaminated sites
4.1 Principle
This clause focuses on the needs of project managers dealing with the remediation of contaminated
sites. Its objective is to give a global overview of the different characterization steps. The main goal
remains sound assessment of activity levels from the selection step for a remediation strategy and
through to the final release of the site.
For the different characterization steps, data quality objectives (DQO) and data quality assessment
(DQA) or similar should be defined and used to ensure efficient characterization.
Figure 2 shows the characterization strategy logic diagram for soils, buildings and infrastructures
contaminated by radioactive substances and associated chemicals.
6 © ISO 2017 – All rights reserved

ISO 18557:2017(E)
Key
Figure 2 — Characterization strategy workflow applied to the remediation of sites
contaminated by radioactive substances (and possible associated chemical substances)
ISO 18557:2017(E)
4.2 Characterization and remediation objectives
Knowledge of the physical and radiological condition of sites and facilities is the most challenging
characterization objective for operators, contributing to plans for appropriate graded actions to be
carried out when the time comes for remediation and dismantling. This objective may concern a whole
site or only part of it.
Remediation or decontamination objectives should be defined or determined in accordance with the
different national regulations. These objectives can be the final criteria for site release or building
decommissioning. They are generally derived from dose risk assessment, taking expected reuse into
account. They may be set by regulations (clearance levels) or negotiated case by case.
As well as contributing to meeting remediation objectives, characterization may also be necessary for
other specific objectives, for example Health and Safety requirements and their impact on clean-up and
dismantling work areas, the estimation of contaminated volumes in order to determine the amount
of radioactive waste to be sent to a storage or a disposal facility, obtaining input data to carry out a
radiation protection or environmental impact study, or, to help estimate remediation costs. At the end
of the remediation process, the goal of the characterization carried out during a final release survey is
to demonstrate that the remediation objectives of the clean-up of all or part of a site have been reached.
Thus, characterization may need to address some or all of the following objectives:
— determination of the radiological fingerprint and chemical composition,
— identification of areas as regards their radiological/chemical characteristics and impacted media,
— determination of the spatial extent of contamination in all the facility structures, systems and
components, as well as the soils around the facility itself and possibly outside the nuclear site,
— determination of the radiological and chemical background around the site,
— verifying results of the numerical model calculations (e.g. activation, migration or diffusion),
— identification and quantification of radionuclides which are difficult to measure,
— helping in modelling the dose calculations, in order to determine the remediation criteria for
buildings and soils,
— helping in selecting decontamination or remediation techniques,
— determination of doses likely to be received by personnel during clean-up and dismantling,
— quantifying the radiation protection actions needed for the dismantling and clean-up work,
— waste categorization in order to decide on its treatment/conditioning, packaging, shipment options
and management route (clearance, recycling, reuse, storage, disposal),
— estimation of the dismantling and remediation costs,
— determination of the dismantling and remediation actions to be undertaken,
— determination of any possible easements needed depending on the final facility or site condition,
— demonstration that the remediation objectives have been met,
— giving formal input to the documentation to be used for final approval/decisions
A characterization should always meet well-defined objectives. This ensures that a robust decision can
be taken as regards the final facility or site condition. Unclear objectives may result in useless data or
over-characterization.
8 © ISO 2017 – All rights reserved

ISO 18557:2017(E)
4.3 Historical analysis
The historical analysis should consider:
— the site context (e.g. geology, hydrogeology, occupations in the
...