ISO 20043-2:2023
(Main)Measurement of radioactivity in the environment — Guidelines for effective dose assessment using environmental monitoring data — Part 2: Emergency exposure situation
Measurement of radioactivity in the environment — Guidelines for effective dose assessment using environmental monitoring data — Part 2: Emergency exposure situation
These international guidelines are based on the assumption that monitoring of environmental components (atmosphere, water, soil and biota) as well as food quality is performed to ensure the protection of human health[5][7][8][9][10][11][12]. The guidelines constitute a basis for the setting of national regulations, standards, and inter alia, for monitoring air, water and food in support of public health, specifically to protect the public from ionizing radiation. This document provides: — guidance to collect data needed for the assessment of human exposure to radionuclides naturally present or discharged by anthropogenic activities in the different environmental compartments (atmosphere, waters, soils, biota) and food; — guidance on the environmental characterization needed for the prospective and/or retrospective dose assessment methods of public exposure; — guidance that addresses actions appropriate for an event involving uncontrolled releases of gamma-emitters (e.g. nuclear power reactor emergencies) and also events that would involve beta- or alpha-emitters would require additional consideration of the pathways, instrumentation, laboratory analysis, operational intervention levels, protective actions, etc., appropriate to their release; — guidance for staff in nuclear installations responsible for the preparation of radiological assessments in support of permit or authorization applications and National Authorities’ officers in charge of the assessment of doses to the public for the purposes of determining gaseous or liquid effluent radioactive discharge authorizations; — information to the public on the parameters used to conduct a dose assessment for any exposure situations to a representative person/population. It is important that the dose assessment process be transparent, and that assumptions are clearly understood by stakeholders who can participate in, for example, the selection of habits of the representative person to be considered. This document refers to various published ISO documents. When appropriate, this document also refers to national standards or other publicly available documents.
Mesurage de la radioactivité dans l'environnement — Lignes directrices pour l’évaluation de la dose efficace à l’aide de données de surveillance environnementale — Partie 2: Situations d'exposition d’urgence nucléaire
General Information
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 20043-2
First edition
2023-07
Measurement of radioactivity in
the environment — Guidelines for
effective dose assessment using
environmental monitoring data —
Part 2:
Emergency exposure situation
Mesurage de la radioactivité dans l'environnement — Lignes
directrices pour l’évaluation de la dose efficace à l’aide de données de
surveillance environnementale —
Partie 2: Situations d'exposition d’urgence nucléaire
Reference number
© ISO 2023
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols . 4
5 Principle . 6
6 Implementation system of monitoring and emergency response plan .9
6.1 General . 9
6.2 Plan and implementation system . 9
6.3 Urgent response phase monitoring . 10
6.4 Early response phase monitoring . 11
6.5 Transition phase monitoring . 12
7 Guidance on emergency measurement .12
7.1 General .12
7.2 Ambient dose equivalent . 13
7.3 Measurement by survey meter and monitoring vehicle . 13
7.4 Aerial monitoring . 13
7.5 Radiation monitoring on surface water . 13
7.6 Environmental media and food monitoring . 14
7.6.1 General . 14
7.6.2 Measurement of radioactive materials in environmental media. 14
7.6.3 Measurement of radioactive materials in food and drink . 14
8 Discussion of Default OILs .14
8.1 Radiation monitoring for OIL 1 . 14
8.2 Radiation monitoring for OIL 2 . 14
8.3 Radiation monitoring for OIL 6 . 15
9 Projected dose assessment based on monitoring results .15
9.1 General . 15
9.2 Projected dose assessment during a release . 16
9.3 Projected dose assessment after a plume passage . 18
10 Laboratory management .19
10.1 Laboratory staff management . 19
10.2 Sample management . 20
10.3 Quality management . 20
10.4 Publication of results . 20
Annex A (informative) OILs for assessing the results of field monitoring and screening of
foodstuff concentrations from laboratory analysis .21
Annex B (informative) Example of operational intervention levels determination related
to living area during plume passage .23
Annex C (informative) Example of operational intervention levels determination related
to living area after a plume passage .27
Bibliography .32
iii
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
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URL: www.iso.org/iso/foreword.html.
This document was prepared by Technical ISO/TC 85, Nuclear energy, nuclear technologies, and
radiological protection, Subcommittee SC 2, Radiological protection.
A list of all parts in the ISO 20043 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
Everyone is exposed to natural radiation. The natural sources of radiation are cosmic rays and
naturally occurring radioactive substances existing in the Earth itself and inside the human body.
Human activities involving the use of radiation and radioactive substances cause radiation exposure in
addition to the natural exposure. Some of those activities, such as the mining and use of ores containing
naturally-occurring radioactive material (NORM) and the production of energy by burning coal that
contains such substances, simply enhance the exposure from natural radiation sources. Nuclear
installations use radioactive materials and produce radioactive effluent and waste during operation
and on their decommissioning. The use of radioactive materials in industry, agriculture and research is
expanding around the globe.
All these human activities generally also give rise to radiation exposures that are only a small fraction
of the global average level of natural exposure. The medical use of radiation is the largest and a growing
man-made source of radiation exposure. It includes diagnostic radiology, radiotherapy, nuclear medicine
and interventional radiology.
Radiation exposure also occurs as a result of occupational activities. It is incurred by workers in
industry, medicine and research using radiation or radioactive substances, as well as by crew during
air travel and by astronauts. The average level of occupational exposures is generally similar to the
[4]
global average level of natural radiation exposure .
As the uses of radiation increase, so do the potential health risk and the public’s concerns increase.
Thus, all these exposures are regularly assessed in order to
a) improve the understanding of global levels and temporal trends of public and worker exposure,
b) evaluate the components of exposure so as to provide a measure of their relative importance, and
c) identify emerging issues that may warrant more attention and scrutiny. While doses to workers
are usually directly measured, doses to the public are usually assessed by indirect methods
using radioactivity measurements results performed on various sources: waste, effluent and/or
environmental samples.
To ensure that the data obtained from radioactivity monitoring programs support their intended use,
it is essential in the dose assessment process that stakeholders (the operators, the regulatory bodies,
the local information committee and associations, etc.) agree on appropriate data quality objectives,
methods and procedures for: the sampling, handling, transport, storage and preparation of test
samples; the test method; and for calculating measurement uncertainty. An assessment of the overall
measurement uncertainty also needs to be carried out systematically. As reliable, comparable and ‘fit
for purpose’ data are an essential requirement for any public health decision based on radioactivity
measurements, international standards of tested and validated radionuclide test methods are an
important tool for the production of such measurement results. The application of standards serves
also to guarantee comparability over time of the test results and between different testing laboratories.
Laboratories apply them to demonstrate their technical competences and to complete proficiency tests
successfully during interlaboratory comparisons, two prerequisites to obtain national accreditation.
Today, over a hundred International Standards, prepared by ISO Technical Committees, including
those produced by this Technical Committee, and the International Electrotechnical Commission, are
available for measuring radionuclides in different matrices by testing laboratories.
Generic standards help laboratories to manage the measurement process, and specific standards
describing test methods are used specifically by those in charge of radioactivity measurement. The
latter cover test methods for:
40 14
— natural radionuclides, including K, tritium, C and those originating from the thorium and
226 228 234 238 220 222 210
uranium decay series, in particular Ra, Ra, U, U, Rn, Rn, and Pb, which can
be found in every material from natural sources or can be released from technological processes
involving naturally occurring radioactive materials (e.g. the mining and processing of mineral sands
or phosphate fertilizer production and use), and
v
— man-made radionuclides, such as transuranium elements (americium, plutonium, neptunium, and
14 90
curium), tritium, C, Sr and gamma emitting radionuclides found in waste, liquid and gases
effluent and in environmental matrices (air, soil, water, biota) as a result of authorized releases into
the environment and of fallout resulting from the explosion in the atmosphere of nuclear devices
and accidents, such as those that occurred in Chernobyl and Fukushima. Radionuclides, such as
tritium and C, occur both naturally and as by-products of the operation of nuclear reactors.
The International Commission on Radiological Protection (ICRP) recognises three types of exposure
[2]
situations that are intended to cover the entire range of exposure situations: planned, emergency
and existing exposure situations. Planned exposure situations involve the planned introduction and
operation of sources (previously categorised as practices). Emergency exposure situations require
prompt action in order to avoid or to reduce adverse consequences. Existing exposure situations are
exposure situations that already exist when a decision on control is taken, such as those caused by
enhanced natural background radiation (e.g. on remediated land).
The fraction of the background dose rate to man from environmental radiation, mainly gamma
radiation, varies considerably, and depends on factors such as the radioactivity of the local rock and
soil, the nature of building materials and the construction of buildings in which people live and work.
This document sets out principles and guidance for the radiological characterisation of the environment
needed for checking the results of
— prospective assessment of dose to the public arising from exposure to ionizing radiation which
may arise from planned discharges to the atmosphere and to the aquatic environment or following
remediation action, and
— retrospective assessment for dose that may be made for discharges or disposals that were not
initially covered by or authorized by a national regulatory body (e.g. contaminated land or dose
associated with accidental releases of radionuclides into the environment).
This document is one of a set of generic ISO Standards on measurement of radioactivity. Example of
dose assessment in different exposure situations are shown in the table below.
Example of dose assessment in different exposure situations, modified from Reference [6]
Type of assessment
Situation
Prospective Retrospective
Determining compliance with the relevant dose
constraint (dose limit or regulatory require-
Estimating dose to the public from past
Planned ments). A prospective assessment includes the
operations
exposures expected to occur in normal opera-
tion.
Future prolonged exposures (e.g. after remedi- Past exposures (e.g. occupancy of contami-
Existing
ation) nated lands)
Emergency planning (operational intervention
Emergency Actual impacts after emergency
level)
Generic mathematical models used for the assessment of radiological human exposure are presented
to identify the parameters that should be monitored in order to select, from the set of measurement
results, the "best estimates" of these parameter values. More complex models are often used that
require the knowledge of supplementary parameters.
Since the Fukushima Daichi nuclear power plant accident in March 2011, an effective emergency
response after a nuclear facility accident is re-emphasized and is summarized as follows. In the initial
stages of an accident, decision makers collect and report monitoring data promptly and determine
appropriate protective measures for the population, such as sheltering, evacuation, and the distribution
of iodine prophylaxis. Teams need to collect reliable information and make adequate decisions for
protective measure determinations. Appropriate prearranged procedures aid in the response to
vi
emergency exposure situations. Also, decision makers should consider the possibility of coincident
events, such as natural disasters and infectious diseases occurring at the same time.
For emergency exposure situations, operational intervention levels are derived from IAEA Safety
[19]
Standards [IAEA GSG-2] .
vii
INTERNATIONAL STANDARD ISO 20043-2:2023(E)
Measurement of radioactivity in the environment —
Guidelines for effective dose assessment using
environmental monitoring data —
Part 2:
Emergency exposure situation
1 Scope
These international guidelines are based on the assumption that monitoring of environmental
components (atmosphere, water, soil and biota) as well as food quality is performed to ensure the
[5][7][8][9][10][11][12]
protection of human health . The guidelines constitute a basis for the setting of
national regulations, standards, and inter alia, for monitoring air, water and food in support of public
health, specifically to protect the public from ionizing radiation.
This document provides:
— guidance to collect data needed for the assessment of human exposure to radionuclides naturally
present or discharged by anthropogenic activities in the different environmental compartments
(atmosphere, waters, soils, biota) and food;
— guidance on the environmental characterization needed for the prospective and/or retrospective
dose assessment methods of public exposure;
— guidance that addresses actions appropriate for an event involving uncontrolled releases of gamma-
emitters (e.g. nuclear power reactor emergencies) and also events that would involve beta- or alpha-
emitters would require additional consideration of the pathways, instrumentation, laboratory
analysis, operational intervention levels, protective actions, etc., appropriate to their release;
— guidance for staff in nuclear installations responsible for the preparation of radiological assessments
in support of permit or authorization applications and National Authorities’ officers in charge of
the assessment of doses to the public for the purposes of determining gaseous or liquid effluent
radioactive discharge authorizations;
— information to the public on the parameters used to conduct a dose assessment for any exposure
situations to a representative person/population. It is important that the dose assessment process
be transparent, and that assumptions are clearly understood by stakeholders who can participate
in, for example, the selection of habits of the representative person to be considered.
This document refers to various published ISO documents. When appropriate, this document also refers
to national standards or other publicly available documents.
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/IEC Guide 98-3, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
me a s ur ement (GUM: 1995)
ISO/IEC Guide 99, International vocabulary of metrology — Basic and general concepts and associated
terms (VIM)
ISO 80000-10, Quantities and units — Part 10: Atomic and nuclear physics
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 80000-10, ISO/IEC Guide 98-3,
ISO/IEC Guide 99 and the following 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 https:// www .electropedia .org/
3.1
atmospheric transfer coefficient
coefficient which characterizes the radioactivity dispersion in the atmosphere at a given location
Note 1 to entry: In the case of a continuous release, it is the ratio between the activity concentration in the air (C )
a
at a given location and the released activity rate ( A ). In the case of a puff release of a duration T it is the ratio
f
T T
f f
between Ctd at a given location and the total released activity Atd .
a
∫ ∫
0 0
Note 2 to entry: The atmospheric transfer coefficient at a given location depends on the distance between the
released position and the given location, the release height, the wind speed and the atmospheric stability, which
is characterized by either normal or weak diffusion according to the temperature difference between 100 m
altitude and the ground level. A diffusion is weak when this temperature difference is positive.
Note 3 to entry: The atmospheric transfer coefficient is usually calculated by valid computer code on the basis of
a mathematical model of atmospheric dispersion.
3.2
background (dose)
dose or dose rate (or an observed measure related to the dose or dose rate) attributable to all sources
other than the one(s) specified
Note 1 to entry: Strictly, this applies to measurements of dose rate or count rate from a sample, where the
background dose rate or count rate must be subtracted from all measurements. However, background is used
more generally, in any situation in which a particular source (or group of sources) is under consideration, to
refer to the effects of other sources. It is also applied to quantities other than doses or dose rates, such as activity
concentrations in environmental media
[SOURCE: IAEA. Vienna: IAEA, 2022. 246 p.]
3.3
detection alarm level
real time measurement value corresponding to an acceptable false alarm rate
Note 1 to entry: When the detection alarm level increases false alarm rate decreases.
Note 2 to entry: The detection alarm level usually far more exceeds the decision threshold.
3.4
emergency action level
EAL
specific, predetermined, observable criterion used to detect, recognize and determine the emergency
class
Note 1 to entry: An emergency action level could represent an instrument reading, the status of a piece of
equipment or any observable event, such as a fire.
[SOURCE: IAEA. Vienna: IAEA, 2022. 246 p.]
3.5
emergency exposure situation
exposure situation that arises as a result of an accident, a malicious act or other unexpected event, and
requires prompt action in order to avoid or to reduce adverse consequences
Note 1 to entry: This may include unplanned exposures resulting directly from the emergency and planned
exposures to persons undertaking actions to mitigate the consequences of the emergency. Emergency exposure
may be occupational exposure or public exposure.
[SOURCE: IAEA. Vienna: IAEA, 2022. 246 p.]
3.6
monitoring
radiation monitoring
measurement of dose, dose rate or activity for reasons relating to the assessment or control of exposure
to radiation or exposure due to radioactive substances, and the interpretation of the results
[SOURCE: IAEA. Vienna: IAEA, 2022. 246 p.]
3.7
environmental monitoring
measurement of external dose rates due to sources in the environment or of radionuclide concentrations
in environmental media
[SOURCE: IAEA. Vienna: IAEA, 2022. 246 p.]
3.8
existing exposure situation
exposure situation which already exists when a decision on the need for control needs to be taken
Note 1 to entry: Existing exposure situation includes exposure to background radiation and exposure to residual
radioactive material from a nuclear or radiological emergency after the emergency exposure situation has been
declared ended.
[SOURCE: IAEA. Vienna: IAEA, 2022. 246 p.]
3.9
operational intervention level
OIL
set level of a measurable quantity that corresponds to a generic criterion
[SOURCE: IAEA. Vienna: IAEA, 2022. 246 p.]
Note 1 to entry: Operational intervention levels are typically expressed in terms of dose rates or of activity of
radioactive material released, time integrated air activity concentrations, ground or surface concentrations, or
activity concentrations of radionuclides in environmental, food or water samples.
Note 2 to entry: An operational intervention level is used immediately and directly (without further assessment)
to determine the appropriate protective actions on the basis of an environmental measurement.
3.10
precautionary action zone
PAZ
area around a facility for which arrangements have been made to take urgent protective actions in the
event of a nuclear or radiological emergency to avoid or to minimize severe deterministic effects off the
site
Note 1 to entry: Protective actions within this area are to be taken before or shortly after a release of radioactive
material or an exposure, on the basis of the prevailing conditions at the facility.
[SOURCE: IAEA. Vienna: IAEA, 2022. 246 p.]
3.11
planned exposure situation
situation of exposure that arises from the planned operation of a source or from a planned activity that
results in an exposure due to a source
[SOURCE: IAEA. Vienna: IAEA, 2022. 246 p.]
3.12
risk
combination of the probability of occurrence of harm and the severity of that harm
Note 1 to entry: The probability of occurrence includes the exposure to a hazardous situation, the occurrence of a
hazardous event and avoid or limit the harm.
[SOURCE: ISO/IEC Guide 51:2014, 3.9]
3.13
screening
type of analysis aimed at eliminating the further consideration of factors that are less significant for
protection or safety, in order to concentrate on the more significant factors
[SOURCE: ISO 20043-1:2021, 3.19]
3.14
source
anything that may cause radiation exposure, such as by emitting ionizing radiation or by releasing
radioactive substances or radioactive materials and can be treated as a single entity for purposes of
protection and safety
[SOURCE: IAEA. Vienna: IAEA, 2022. 246 p.]
3.15
source term
amount and isotopic composition of radioactive material released (or postulated to be released) from a
facility
Note 1 to entry: Used in modelling releases of radionuclides to the environment, in particular in the context of
accidents at nuclear installations or releases from radioactive waste in repositories.
[SOURCE: IAEA. Vienna: IAEA, 2022. 246 p.]
3.16
urgent protective action planning zone
UPZ
area around a facility for which arrangements have been made to take urgent protective actions in the
event of a nuclear or radiological emergency to avert doses off the site in accordance with international
safety standards
Note 1 to entry: Protective actions within this area are to be taken on the basis of environmental monitoring or,
as appropriate, prevailing conditions at the facility.
[SOURCE: IAEA. Vienna: IAEA, 2022. 246 p.]
4 Symbols
Table 1 — Symbols
Symbol Definition Unit
-1
Released activity rate Bq·s
A
-1
Released activity rate of radionuclide i Bq·s
A
i
TTabablele 1 1 ((ccoonnttiinnueuedd))
Activity concentration in the air due to
-3
CX Bq·m
()
a
the plume at location X
Activity concentration of beta gamma
-3
CX()
emitters in the air due to the plume at Bq·m
a,βγ
location X
Activity concentration of alpha emitters in
-3
CX()
Bq·m
a,α
the air due to the plume at location X
Atmospheric transfer coefficient of radio-
-3
CTA (X) s·m
i
nuclide i at location X
Committed effective dose per unit inhala-
-1
E (i) Sv·Bq
inh
tion of radionuclide i
Committed effective dose per unit inges-
-1
E (i) Sv·Bq
ing
tion of radionuclide i
Effective dose rate due to external expo-
-1
EX() Sv·s
pe, xt
sure from the plume at location X
Effective dose rate due to external
-1
EX() exposure from the ground deposition at Sv·s
de, xt
location X
Effective dose rate due to external expo-
-1
E Sv·s
de, xt
sure from the ground deposition
Effective dose due to inhalation at loca-
EX()
Sv
pi, nh
tion X
Effective dose due to resuspension from
EX
() Sv
di, nh
the ground deposition at location X
Effective dose due to ingestion at location
EX()
Sv
ing
X
Effective dose due to the ground deposi-
EX Sv
()
d
tion at location X
Effective dose due to the plume at location
EX
() Sv
p
X
Effective dose due to external exposure
EX()
Sv
pe, xt
from the plume at location X
Effective dose due to external exposure
EX
() Sv
de, xt
from the ground deposition at location X
Ambient dose equivalent rate conversion
-1 -1 2
f (Sv·s ·Bq )·m
CDdi
factor due to deposition of radionuclide i
Ambient dose equivalent rate conversion
-1 -1 3
f (Sv·s ·Bq )·m
CDpi
factor due to the plume of radionuclide i
-1
L Generic action level for foodstuffs Bq·kg
GA
*
Ambient dose equivalent at 10 mm depth Sv
H ()10
Ambient dose equivalent rate at 10 mm
* -1
Sv·s
H 10
()
depth
Detector beta gamma emitter conversion
-1 -2
I γ (counts·s )·Bq·m
Cβ i
factor of radionuclide i
Detector alpha emitter conversion factor
-1 -2
I (counts·s )·Bq·m
Cαi
of radionuclide i
Committed equivalent dose to the thyroid
H (X) Sv
thy
at location X
Operational intervention level at location
YY
()
X corresponding to an effective or equiv- unit of the measure-
OILX ,,E type of measurement
alent dose limitation at location Y for a ment type
HY
()
given type of measurement
TTabablele 1 1 ((ccoonnttiinnueuedd))
Net count rate resulting from a meas-
urement in contact of the ground by a
-1
r (X) s
net
portable surface contamination detector
at location X
Net count rate resulting from a measure-
ment on the ground contact by a portable
-1
r (X) s
βγ/net
surface contamination beta gamma emit-
ters detector at location X
Net count rate resulting from a measure-
ment on the ground contact by a portable
-1
r (X) s
α/net
surface contamination alpha emitters
detector at location X
Ingestion transfer rate factor from the
2 -1
R m ·s
ing
contaminated ground
Resuspension factor from the contaminat-
-1
R m
s
ed ground to the air
T Exposure duration h
E
Activity release duration which is also the
T h
R
exposure duration due the plume
deposit speed to the ground of radionu-
-1
V m·s
di
clide i
5 Principle
The purpose of monitoring in emergency exposure situation is to understand the radiation dose level
in the environment and to provide information for judgment on implementation of protective measures
such as evacuation and sheltering and iodine prophylaxis.
Therefore, in case of emergency, it is also possible to evaluate radiation dose levels using a planned
and existing monitoring system, as well as temporary monitoring systems including aircraft-mounted
systems that enable the monitoring of a wide area.
[13]
In a nuclear or radiological emergency, the practical goals of emergency response are :
— to regain control of the situation and to mitigate consequences;
— to save lives;
— to avoid or to minimize severe deterministic effects;
— to render first aid, to provide critical medical treatment and to manage the treatment of radiation
injuries;
— to reduce the risk of stochastic effects;
— to keep the public informed and to maintain public trust;
— to mitigate, to the extent practicable, non-radiological consequences;
— to protect, to the extent practicable, property and the environment;
— to prepare, to the extent practicable, for the resumption of normal social and economic activity.
Until recently, international guidance on emergency preparedness and response were based on
a technical/analytical approach. To summarize, this approach modelled the emergency scenario,
analysed the dose reduction options, and used intervention principles to select the best solution
for implementation. In recent years, guidance has expanded to include a management approach
(see Figure 1) that considers more than just the immediate event response. This expanded approach
involves focusing not only on intervention principles, but also on goal setting for the outcome of
emergency response. This expanded approach would be most critical for nuclear emergencies expected
to impact the post-event radiological background conditions. Goals may be based on experience gained
from past emergencies. In other words, the conception is to set a target value for keeping the dose of the
public below a certain value and to make a plan. This shift in approach has been reflected recently in
the international community's agreement on standards.
Figure 1 — Management approach for emergency exposure situation modified from
Reference [14]
[13]
The system of generic and optional criteria is described in Table 2 . Facilities with a stringency of
requirements for preparedness and response arrangements of hazard are classified as category I, II
and III.
Emergency preparedness category IV applies to activities with a minimum level of hazard, which is
assumed to apply for all states and areas. Emergency preparedness category V applies to the off-site
areas where arrangements for preparedness and response are warranted to deal with contamination
resulting from a release of radioactive material from a facility in emergency preparedness category I or
II.
Table 2 — Five categories of nuclear and radiation related hazards for the purposes of the
[13]
requirements
Category Description
Facilities, such as nuclear power plants, for which on-site events (including not considered
in the design) are postulated that could give rise to severe deterministic effects off the site
that would warrant precautionary urgent protective actions, urgent protective actions or
I
early protective actions, and other response actions to achieve the goals of emergency re-
sponse in accordance with international standards, or for which such events have occurred
in similar facilities.
Facilities, such as some types of research reactors and nuclear reactors used to provide
power for the propulsion of vessels (e.g. ships and submarines), for which on-site events
are postulated that could give rise to doses to people off the site that would warrant urgent
protective action or early protective actions and other response actions to achieve the
II goals of emergency response in accordance with international standards, or for which such
events have occurred in similar facilities. Emergency preparedness category II (as opposed
to emergency preparedness category I) does not include facilities for which on-site events
(including those not considered in the design) are postulated that could give rise to severe
deterministic effects off the site, or for which such events have occurred in similar facilities.
Facilities, such as industrial irradiation facilities or some hospitals, for which on-site events
are postulated that could warrant protective actions and other response actions on the site
to achieve the goals of emergency response in accordance with international standards,
III or for which such events have occurred in similar facilities. Category III (as opposed to
category II) does not include facilities for which events are postulated that could warrant
urgent protective action or early protective actions off the site, or for which such events
have occurred in similar facilities.
Activities and acts that could give rise to a nuclear or radiological emergency that could
warrant urgent protective actions to achieve the goals of emergency response in accordance
with international standards in an unforeseeable location. These activities and acts include:
(a) transport of nuclear or radioactive material and other authorized activities involving
mobile dangerous sources such as industrial radiography sources, nuclear powered satellites
or radioisotope thermoelectric generators; and (b) theft of a dangerous source and use of a
IV
radiological dispersal device or radiological exposure device. This category also includes:
(i) detection of elevated radiation levels of unknown origin or of commodities with con-
tamination; (ii) identification of clinical symptoms due to exposure to radiation; and (iii)
a transnational emergency that is not in category V arising from a nuclear or radiological
emergency in another State. Category IV represents a level of hazard that applies for all
States and jurisdictions.
Areas within emergency planning zones and emergency planning distances in a State for
V
facility in category I or II located in another State.
In particular, plans are required in advance for the following items in order to effectively implement
off- site emergency protection measures for facilities in emergency preparedness categories I and II.
Operational intervention levels (OIL) and emergency action levels (EAL) are criteria (e.g. specific
observables or other indicators) to be used in decision-making. Meeting the criteria would trigger the
need to implement appropriate protective actions and other responses. Annex A provides an example
of OILs used for assessing the results of field monitoring and screening of foodstuff concentrations
from laboratory analysis. In the emergency, it is necessary for the government to manage radiation
monitoring and ensure that wide area monitoring can be implemented.
When an event is severe enough that impacts are quite widespread or may require an extended clean-
up time, two types of zones may be established. A precautionary action zone (PAZ) may be established
for preventive emergency protection to keep doses below the expected dose of intervention to
prevent severe deterministic effects. An urgent protective action planning zone (UPZ) would also be
established to urgently implement protective action measures to prevent to doses off-site in accordance
with international standards. Protective actions within the UPZ area are to be taken on the basis of
environmental monitoring or, as appropriate, prevailing conditions at the facility.
In emergency exposure situations, the operating organization (registrant or licensee) is in charge of
source monitoring and near field environmental monitoring. The regulatory body is in charge of large
scale and also near field environmental monitoring.
6 Implementation system of monitoring and emergency response plan
6.1 General
Monitoring and emergency response are implemented when a nuclear or radiological emergency
occurs. Monitoring is carried out appropriately taking into account the circumstances and progress of
the accident. Consideration of the event phase, i.e. early, pre-release and release, and post-release, will
guide the type of monitoring and actions to implement. When monitoring occurs, the health and safety
of the staff performing the monitoring should be considered in procedures.
6.2 Plan and implementation system
In general, the government prepares an emergency response planning in advance, which includes an
emergency monitoring plan, on behalf of their population to prepare for nuclear emergencies. These
plans are coordinated with radiological facility staff and response organisations (e.g. police, fire,
emergency medical services, radiological response teams and health care facilities). Plans should aim
to compile and distribute information and collect, process, and interpret monitoring and event data in
a format compatible with efficient event response. Appropriate staffing, expertise, and training should
be part of planning. The emergency monitoring plan includes the specific implementation system and
responsible staff, according to the accident type.
Instruments, supplies, equipment, communication systems, facilities and manuals should be provided
for performing the specified function or task required in response to a nuclear or radiological
emergency. Arrangements should be established with the laboratories analysing the environmental
and biological samples during the emergency response. Emergency planning should consider whether
these facilities would remain operational for normal business, close, or focus on emergency response
under postulated emergency conditions.
Appropriate staging of adequate emergency response supplies is important. Radiation measurement
devices, distribution, quantity an
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