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| ICRP PUBLICATION 101: ASSESSING DOSE OF THE REPRESENTATIVE PERSON FOR THE PURPOSE OF RADIATION PROTECTION OF THE PUBLIC AND THE OPTIMISATION OF RADIOLOGICAL PROTECTION
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By
. International Commission on Radiological Protection
Included in series
International Commission on Radiological Protection, 101
Description
Assessing dose of the representative person forthe purpose of radiation protection of the public
The Commission intended that its revised
recommendations should be based on a
simple, but widely applicable, system of protection that would clarify its objectives and provide
a basis for the more formal systems needed by operating managers and regulators. The
recommendations would establish quantified constraints,
or limits, on individual dose from
specified sources. These dose constraints apply to actual or representative people who
encounter occupational,
medical, and public exposures. This report updates the previous
guidance for estimating dose to the public. Dose to the public cannot
be measured directly
and, in some cases, it cannot be measured at all. Therefore, for the purpose of protection of the
public, it is
necessary to characterise an individual, either hypothetical or specific, whose dose
can be used for determining compliance with the
relevant dose constraint. This individual is
defined as the ?representative person?. The Commission?s goal of protection of the public
is
achieved if the relevant dose constraint for this individual for a single source is met and
radiological protection is optimised.
This report explains the process of estimating annual dose and recognises that a number of
different methods are available for this purpose.
These methods range from deterministic
calculations to more complex probabilistic techniques. In addition, a mixture of these techniques
may be applied. In selecting characteristics of the representative person, three important
concepts should be borne in mind: reasonableness,
sustainability, and homogeneity. Each
concept is explained and examples are provided to illustrate their roles. Doses to the public are
prospective (may occur in the future) or retrospective (occurred in the past). Prospective doses
are for hypothetical individuals who
may or may not exist in the future, while retrospective
doses are generally calculated for specific individuals.
The Commission recognises
that the level of detail afforded by its provision of dose coefficients
for six age categories is not necessary in making prospective
assessments of dose, given
the inherent uncertainties usually associated with estimating dose to the public and with
identification of
the representative person. It now recommends the use of three age categories
for estimating annual dose to the representative person
for prospective assessments. These
categories are 0?5 years (infant), 6?15 years (child), and 16?70 years (adult). For practical
implementation
of this recommendation, dose coefficients and habit data for a 1-year-old
infant, a 10-year-old child, and an adult should be used to
represent the three age categories.
In a probabilistic assessment of dose, whether from a planned facility or an existing situation,
the Commission recommends that the representative person should be defined such that
the probability is less than about 5% that a person
drawn at random from the population will
receive a greater dose. If such an assessment indicates that a few tens of people or more could
receive doses above the relevant constraint, the characteristics of these people need to be
explored. If, following further analysis,
it is shown that doses to a few tens of people are indeed
likely to exceed the relevant dose constraint, actions to modify the exposure
should be considered.
The Commission recognises the role that stakeholders can play in identifying characteristics
of the representative
person. Involvement of stakeholders can significantly improve the
quality, understanding, and acceptability of the characteristics of
the representative person
and the resulting estimated dose.
The optimisation of radiological protection: Broadening the process
The
principle of optimisation of radiation protection is defined by the Commission
as the source-related process to keep the magnitude of
individual doses, the number of people
exposed, and the likelihood of potential exposure as low as reasonably achievable below the
appropriate
dose constraints, with economic and social factors being taken into account.
According to the revised recommendations of ICRP, this process
of optimisation below
constraint should be applied whatever the exposure situation; i.e. planned, emergency, and
existing.
The previous
recommendations for the practical implementation of the optimisation process
are still valid. It must be implemented through an ongoing,
cyclical process that involves the
evaluation of the exposure situation to identify the need for action, the identification of the
possible
protective options to keep the exposure as low as reasonably achievable, the selection
of the best option under the prevailing circumstances,
the implementation of the selected option
through an effective optimisation programme, and regular review of the exposure situation to
evaluate if the prevailing circumstances call for the implementation of corrective protective
actions. However, the way in which the
optimisation process should be implemented is now
viewed more broadly to reflect the increasing role of individual equity, safety culture,
and
stakeholder involvement in our modern societies.
This report is a consolidation and an evolution of the Commission?s recommendations
concerning the optimisation principle. After some background information on the foundation
and evolution of the principle, this report
describes the main characteristics of the process,
addresses the issue of exposure distribution in that process, and provides the basic
requirements
for its application in operation and regulation. A description of decision-aiding techniques
commonly used for practical
implementation of the optimisation process is provided in
Annex A.
Contents
Assessing dose of the representative person forthe purpose of radiation protection of the public
1. INTRODUCTION
1.1.
Objective
1.2. Background
1.3. Fundamental principles and concepts
2. ASSESSMENT OF DOSE
2.1. Purpose of dose assessment
2.2. Types of dose assessment
2.3. Overview of the dose-assessment process
2.4. Treatment of uncertainties in dose assessment
2.5. Deterministic and probabilistic methods for dose assessment
3. THE REPRESENTATIVE PERSON
3.1. Definition of the representative
person
3.2. Pathways of exposure, time frames, and spatial distribution of radionuclides
3.3. Characteristics of the representative
person
3.4. Age-specific dose coefficients
3.5. Determining compliance
4. OTHER CONSIDERATIONS RELEVANT TO THE REPRESENTATIVE
PERSON
4.1. Relationship between environmental monitoring, modelling, and the representative person
4.2. Situations of potential
exposure
4.3. Value of stakeholder input to characterising the representative person
ANNEX A: ANALYSIS OF AGE CATEGORIES FOR
USE IN ASSESSMENT OF DOSE TO THE PUBLIC
ANNEX B: DETERMINING COMPLIANCE WHEN DOSE TO THE PUBLIC IS ESTIMATED PROBABILISTICALLY.
The optimisation of radiological protection: Broadening the process
1. INTRODUCTION
2. THE HISTORY OF THE OPTIMISATION
PRINCIPLE
2.1. Foundation of the principle
2.2. Evolution of the concept
2.3. Recent developments
3. THE OPTIMISATION
PROCESS
3.1. Framing the process
3.2. Characteristics of the process
3.3. Stakeholder involvement
3.4. Selection of the
best option
4. EXPOSURE DISTRIBUTION
4.1. Use of collective dose
4.2. Exposure distributions in time and space
4.3. Collective
dose matrix and decision-making process
5. THE APPLICATION OF OPTIMISATION IN OPERATION AND REGULATION
ANNEX A: OPTIMISATION
AND DECISION-AIDING TECHNIQUES
Bibliographic & ordering Information
Paperback, publication date: APR-2007
ISBN-13: 978-0-7020-2927-1
ISBN-10: 0-7020-2927-0
Imprint: ELSEVIER
063/663
Last update: 18 Jul 2008
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