Occupational Intakes of Radionuclides Part 1 - ICRP

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DRAFT REPORT FOR CONSULTATION
1 INTRODUCTION
1.1 Purpose of this report series
(1) Occupational intakes of radionuclides may occur during routine operations in
a range of industrial, medical, educational and research facilities. They may also occur
as a result of a nuclear accident, after an incident involving radioactive material,
during post-accident remediation work at a nuclear installation, or during
environmental remediation activities.
(2) An adequate assessment of occupational internal exposure resulting from
intakes of radionuclides is essential for the design, planning and authorisation of a
facility or activity, for the optimisation of radiation protection of workers, for
operational radiation protection and for the retrospective demonstration of compliance
with regulatory requirements.
(3) After intake of radionuclides, doses received by organs and tissues are
protracted over time and so equivalent and effective doses are accumulated over time.
The resulting quantities are referred to as committed doses.
(4) Internal exposure of workers should be assessed in terms of the protection
quantity committed effective dose The individual exposure of a worker should be
assessed and recorded in terms of dose of record, which takes into account both
internal and external exposures.
(5) This report series provides a comprehensive set of dose coefficients (i.e.
committed effective dose and committed equivalent dose per unit intake (DPUI)) and
also provides values for committed effective dose and committed equivalent dose per
unit content (DPUC).
(6) These data may be used for both prospective assessments and retrospective
assessments. Prospective assessments provide estimates of intakes and resulting doses
for workers engaged in specific activities using information on potential exposures to
radionuclides obtained at the design and planning stage of a facility or practice.
Retrospective assessments use the results of individual monitoring and workplace
monitoring to assess doses in order to maintain individual dose records and
demonstrate compliance with regulatory requirements. Prospective assessments
generally make use of default assumptions about exposure conditions and default
values for parameters describing material-specific properties such as the particle size
distribution of an inhaled aerosol or the absorption characteristics of a material after
inhalation or ingestion. Retrospective assessments may in some circumstances make
use of specific information relating to the exposure, as discussed in Chapter 6.
(7) The report series contains detailed information on the ICRP reference models
used for the derivation of dose coefficients. The information provided in this first
report of the series includes a description of revisions made to the ICRP reference
Human Respiratory Tract Model (ICRP, 1994a) and an overview of the ICRP
reference Human Alimentary Tract Model (ICRP, 2006). Subsequent reports in the
series present descriptions of the structures and parameter values of the reference
systemic biokinetic models,
(8) This report also presents an overview of monitoring methods and
programmes, and generic guidance on the interpretation of the bioassay data.
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