Research Reactor Decommissioning Demonstration Project (R2D2)
Release of Buildings and Sites/Final Survey
Humboldt Bay, Eureka, California
28 September - 2 October 2015
10. IAEA Recommendations on the Release
of Materials / Buildings and Sites
Vladan Ljubenov
Division of Radiation, Transport and Waste Safety
Waste and Environmental Safety Section
IAEA
International Atomic Energy Agency
Content
• Context
• Terminology
• The process for release of sites from regulatory
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control - general
Protection and safety aspects
Definition of release criteria
Responsibilities
Details of the process - site characterization,
cleanup actions, release of materials (clearance),
release of buildings, final survey
Unrestricted / restricted use after release
Summary
References
Context
• We are still in decommissioning !!!
• Dismantling and decontamination activities for the SSCs are completed
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and the associated waste is removed.
We are dealing with the site of the former facility, on which some
remaining building structures may exist.
The objective is to release the site from regulatory control (to complete
the decommissioning process).
Release of sites is an authorised activity !!!
The site and the remaining building structures may be contaminated, so
they may require a cleanup actions to be performed to meet the site
release criteria.
This presentation does not cover situations after an accident.
During cleanup and release of sites, release of materials from regulatory
control (clearance) may occur. Clearance is not addressed in details in
this presentation.
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Terminology
• At the end of the operational phase (prior to decommissioning) we deal
with a facility. It includes all the SSCs, the associated land, buildings and
equipment in which radioactive material is used, processed, handled or
stored.
• During decommissioning the SSCs of the facility are gradually dismantled
and removed.
• Towards the end of the decommissioning there is no facility anymore. We
now deal with a site – in the context of release of sites it is defined as
land together with any buildings or other remaining structures being
considered for release from regulatory control.
• In order to meet the criteria for site release, a cleanup may be needed any measures that may be carried out to reduce the radiation exposure
from existing contamination through actions applied to the contamination
itself (the source) or to the exposure pathways to humans and to the
environment.
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Terminology
• Cleanup plan – a document prepared by the operator which describes
cleanup actions and protective measures to be implemented. Usually is
part of the overall decommissioning plan.
• Release from regulatory control – general term, used for both
material/waste and sites
• Clearance – specific term used for release of material/waste from
regulatory control
• Waste – not needed, no intention for reuse/recycle, has to be disposed off,
could be non-radioactive or radioactive waste
• Material – intended for reuse/recycle
• Clearance is different than discharge - planned and controlled release of
(usually gaseous or liquid) radioactive material to the environment during
normal operation of a facility, within limits authorized by the regulatory
body, generally with the purpose of dilution and dispersion
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WS-G-5.1 published in 2006
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The Process for the Release of Sites from
Regulatory Control
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Identification of the site release criteria (generic or site specific)
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Review/approval by the regulatory body
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Preparation of the Final Radiological Survey Report and submission to the RB
Site characterization
Comparison of the site characterization results with the site release criteria
If the site does not meet the release criteria, cleanup actions will be needed
Evaluation of the cleanup options, selection of an optimal cleanup option and end-point
Development of a Cleanup Plan by the operator (preferably as part of the overall
decommissioning plan, should define restrictions, if any)
Implementation of the cleanup actions
Final radiological survey to demonstrate compliance with the site release criteria for
restricted or unrestricted release
Review of the Final Radiological Survey Report by the RB
Independent confirmatory survey by the RB (optional)
Decision by the regulator on release of site (with or without restrictions)
Implementation of restrictions, institutional control and monitoring (if any), record keeping
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This process should be part
of the decommissioning
process, and should be done
under the decommissioning
authorization (licence).
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Protection and Safety Aspects
• The release of sites from regulatory control is the final stage of the
decommissioning process – falls under the planned exposure situation.
• Requirements of the GSR Part 6 (decommissioning) and the GSR Part 3
(BSS) for planned exposure situations are applicable to cleanup and
release of sites.
• All the other requirements referenced in these publications are applicable
as well.
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Protection and Safety Aspects
• Objective - to ensure proper protection of workers, the public and the
environment during the cleanup and after the release of the site.
• The principles of justification, dose limitation and optimization of
protection are applicable to cleanup and release of sites.
• Dose limit of 1 mSv in a year for a member of the public is an upper
bound for the sum of all exposures arising from authorized activities.
• Optimization of protection should include:
• evaluation of the exposure of workers during cleanup activities (i.e. including
material characterization and radioactive waste management);
• evaluation of long term exposure of the public arising from the residual site
contamination after site release.
• This evaluation need to ensure that the protection of workers and the
public is optimized below the dose constraints defined by the RB.
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Protection and Safety Aspects
• This dose constraint should take into account multiple pathways of
exposure and should not exceed 300 μSv in a year above background.
• Prospective effective doses to members of the public above the background
levels (before the commissioning of the facility) that would be received after
the site has been released;
• Summed effective doses arising from the site (considered as one source),
including land and buildings and other structures;
• The uncertainties associated with knowledge of the site and its potential uses
after its release should be taken into account in the estimation of prospective
doses.
• The applicable dose constraint for the public after the release of a site
should be expected to be no higher than that applied for the operational
phase of the facility lifetime.
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Protection and Safety Aspects
• The site dose release criteria should be based on an optimization of
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protection below that dose constraint, with account taken of the fact that
optimization below the order of 10 μSv in a year might not be warranted
on radiological protection grounds.
For the unrestricted use of a site, it should be ensured by means of the
optimization of protection that the effective dose to a member of a critical
group is kept below the dose constraint of 300 μSv in a year.
For the restricted use of a site it should be ensured that, with restrictions
in place, the effective dose should not exceed the dose constraint of 300
μSv in a year and that if the restrictions were to fail in the future the
effective dose should not exceed 1 mSv in a year.
Note the difference from the criteria for release of materials !!! (see
Workshop #9, Karlsruhe 2010)
It is reasonable and appropriate to have different dose constraints for the
release of sites than for the clearance of material from regulatory control.
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Protection and Safety Aspects
• Clearance of material may take place frequently during operation and
decommissioning of a facility, as well as at the termination stage.
• The cleared material may enter into trade with a broad range of potential
uses and therefore should comply with clearance criteria, which are of
the order of 10 μSv in a year.
• The dose criteria for the release of land from regulatory control should be
optimized and can be higher than those for the clearance of material.
• Land remains in place, higher degree of certainty about the potential uses of
the land after its release from regulatory control
• No possibility to simultaneous exposure to more than one site
• It is reasonable to allow a larger fraction of the individual dose limit for the
release of sites (i.e. less than 300 μSv in a year) than for the clearance of
material (of the order of 10 μSv or less in a year).
• Some countries apply a 10 µSv/y concept also for the release of sites.
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Radiological Approach to the Release of Sites
from Nuclear Regulatory Control (WS-G-5.1)
Region for release
of a site for
restricted use if
restrictions fail
Region of
optimization for
site release for
restricted use
provided that
restrictions are
in place
Dose limit (1mSv in a year)
Dose constraint (300 Sv in a year)
Optimised site dose release criteria
10  Sv in a year
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Region of optimization
for unrestricted site
use
Region where dose
reduction measures
are unlikely to be
warranted / release of
materials from
regulatory control
Protection and Safety Aspects
• As part of the decision making process for the release for unrestricted
use of land and associated buildings or structures, consideration should
be given to the potential circulation of material arising from any future
modification of the buildings, including demolition after release of the site.
• Material originating from a released site needs to comply with the
national requirements for radiation protection for material outside the
scope of regulatory control.
• The assessment of material originating from the site should be an integral
part of the optimization analysis for the cleanup process.
• Scenarios giving rise to exposure from sites released for unrestricted use
should be realistic and should consider the potential uses of the material
from the released site.
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Definition of Release Criteria
• The release criteria are defined on the basis of the evaluation of potential
radiological consequences associated with the site after its release.
• All relevant exposure pathways should be considered. The dose
assessment should include direct radiation, inhalation and ingestion
pathways to derive release criteria.
• Two main approaches can be taken
• The RB may develop generic release criteria;
• The operator can derive site specific release criteria, on the basis of the
optimization process, which the RB should then approve.
• The first approach may result in conservative release criteria because of
the generic assumptions in the dose assessment. This could lead to
cleanup activities being more extensive and costly than necessary.
• The second approach places an additional burden on the operator and
the RB, but it is likely to result in a less stringent set of release criteria for
the site.
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Definition of Release Criteria
• An optimization process should be used to develop release criteria.
• In accordance with the guidance of the regulatory body, the operator
should determine which scenarios and which corresponding exposure
pathways are most applicable for the site.
• Involvement of interested parties is important in the selection of the
scenarios to be evaluated (e.g. in identifying the potential activities at the
site after release).
• The selected scenarios and pathways should be used as the basis for
dose assessments to develop release criteria for the site.
• The release criteria are derived from an iterative analysis of a set of all
reasonable scenarios, with account taken of the uncertainties in relation
to the characteristics of the site and its potential use.
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Definition of Release Criteria
• The following activities should be performed on the basis of optimization
of the overall decommissioning actions, the end state of the site as
defined in the decommissioning plan, the associated dose criteria, the
dose constraints and the site description:
• Definition of the scenarios and identification of the exposure pathways;
• Compilation of the specific data and information for the scenarios and
pathways;
• Definition of the conceptual models for the site;
• Conduct of dose assessments;
• Determination of the release criteria.
• The release criteria should be expressed in measurable and verifiable
units (Bq/g or Bq/cm2).
• The IAEA does not provide radionuclide specific site release levels (as it
does for the release of materials)
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Definition of Release Criteria
• The release criteria should take into account the background radiation
levels existing on the site prior to the operation of the facility, as well as
the baseline concentrations of natural radionuclides in the construction
materials (concrete, metals, or any other respective material).
• Before commissioning a new facility, the operator should ensure that a
baseline radiological survey of the site is performed to define the levels of
background radiation at the facility site.
• For existing facilities for which no such baseline survey was carried out in
the past to determine these background levels, data from analogous,
undisturbed areas with similar characteristics should be used.
• Uncertainties should be taken into account in determining the impact of
the release of the site, in optimizing the protection and in defining the
release criteria:
• Uncertainties related to the level of contamination, hidden buried structures
and waste, uncertainties associated with the future use of the remaining
buildings on the released site
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Responsibilities - Government
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Formulate a policy for the release of sites, including cleanup;
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Specify the responsibilities of the parties involved;
Ensure that an adequate legal and regulatory framework, supported where
necessary by appropriate guidance, is in place so that workers, the public and the
environment are protected during cleanup and after the release of sites from
regulatory control;
The legal and regulatory framework should ensure:
• provision for the termination of a practice and release of a site for (un)restricted use;
• basis for establishing any restrictions that may be placed upon the site use/access;
• time frames for institutional control;
• availability of adequate funding mechanisms and definition of responsibilities for
financing of cleanup, including maintaining restrictions;
• Information/record management in accordance with the records retention requirements
(particularly important where restrictions are imposed on the future use of sites);
• provision for the RB to review and approve the proposed cleanup actions (as part of a
decommissioning plan).
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Responsibilities – Regulatory Body
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Establish safety requirements and guidelines for the planning, approval and
conduct of cleanup actions, for the management of contaminated material and
the waste that arises from this process, and for the release of land, buildings and
structures from regulatory control;
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Establish, promote and adopt criteria and guidance for the cleanup and release of
sites as a part of decommissioning;
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Review and approve submissions from operators for cleanup and release of the
site from regulatory control as part of the decommissioning plan (including the
proposed cleanup actions and release criteria for the site);
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Develop criteria and methods for assessing the adequacy of the implementation
of cleanup;
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Issue, amend, suspend or revoke authorization for decommissioning, including
provision for cleanup and release of sites from regulatory control;
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Perform regulatory inspections (e.g. independent measurements) to verify that
safety requirements and conditions for authorization have been met and that the
site meets the approved release criteria after cleanup;
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Responsibilities – Regulatory Body
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Review of final radiological survey documentation;
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Evaluate and approve revised cleanup actions and/or institutional control
measures if compliance with the release criteria is not achieved;
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Evaluate reports on unplanned occurrences and events;
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Cooperate with other relevant authorities and interact with interested parties,
providing them with the necessary information on safety matters associated with
the cleanup and release of the site;
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If the operator is unable to fulfil its responsibilities to ensure release of the site in
compliance with established regulatory criteria, the RB should exercise its
authority to select a competent organization to finalize the cleanup using the
financial arrangements provided by the operator or an authorized party;
Take appropriate actions whenever safety requirements and conditions for
authorization are not met;
Coordinate the regulatory process of cleanup and release of sites with other
regulatory bodies responsible for other issues such as nonradiological hazards
and transport;
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Responsibilities – Regulatory Body
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If no funds or insufficient funds are available for completion of the cleanup of the
site for unrestricted use, the RB should approve the measures for restricted use
and should define procedures and responsibilities for the cleanup of the site, the
maintenance of restrictions, the suspension of authorization and the release of
the site;
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Ensure that relevant documents and records are prepared by the operator, kept
for an agreed time and maintained to a specified quality by appropriate parties
before, during and after decommissioning;
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In the event that the operator ceases its activities or ceases to exist, the RB
should take or assign the responsibility for keeping records about the site;
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Ensure that an effective record management system for the released sites is in
place and is maintained for future users of the sites.
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Responsibilities – Operator (Licensee)
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Overall responsibility for safety (including the cleanup of the site);
• Although the performance of specific tasks may be delegated to a
subcontractor, the ultimate responsibility for safety remains with the operator.
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Preparing and submitting to the regulatory body details of the cleanup actions
and protective measures to be taken during and after the cleanup of the site.
These documents will normally be part of the decommissioning plan and the
supporting documentation;
• WS-G-5.1 provides an example of the content of a cleanup plan.
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Ensuring the availability of the resources (including financial resources),
expertise/knowledge necessary for the cleanup and release of the site;
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Performing the required cleanup actions, after their approval by the regulatory
body, and demonstrating that the release criteria for the site have been met;
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Management of all the cleanup actions, including management of the radioactive
waste generated during cleanup in a way compliant with the relevant safety
requirements and criteria.
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Site Characterization
• Objective – to assess radiological conditions on the site and the need for
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a cleanup prior to the site release and to provide an input for definition of
the site release criteria.
Media for characterization – soil (surface, subsurface), groundwater,
building structures
Do not forget to characterize other hazards that may be present on the
site after completion of the dismantling of the facility (conventional
hazards, chemicals, bio-hazards).
Site characterization should be included in the characterization plan
developed for decommissioning.
Take into account the history of the site and the operational history of the
former facility.
Search for existing data / information, retrieve information from (former)
staff.
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Site Characterization
• Perform sampling and measurements to identify radiological
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contaminants and concentrations.
Result of the characterization – 3D radionuclide distribution
• Type and concentration of radionuclides
• Homogeneity / heterogeneity
• Contamination from leaks in tanks and pipes
• Contamination below buildings
• Other hidden and buried contaminated structures
Use of the results – to determine the need for and the extent of cleanup
actions.
Do not mix the site characterization with the final survey.
Final survey has objective to demonstrate compliance with the release
criteria after the completion of the cleanup actions.
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Cleanup Actions
• Excavation of contaminated soil
• Equipment / technology
• Avoid any re-contamination !
• Measurement to a predetermined gamma
level (exclusion of natural radionuclides)
• Clearance decision on excavated soil
• Release of soil or management as
radioactive waste
• Identify a destination for the waste
• Backfill of excavations with
uncontaminated soil ?
• Take, maintain and store samples and
records of cleanup activities
• Have cleanup levels been achieved?
• Is unrestricted release possible? Iterative
approach – “remove-measure”
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Release of Materials from Nuclear Regulatory
Control during the Cleanup Process
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During cleanup of a site, radioactively contaminated material that is subject to
regulatory control, with no intended future use, should be managed as radioactive
waste at authorized RAW facilities in accordance with the characteristics of the
material and its associated hazards.
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Some contaminated material with a very low level of radioactivity may be suitable
for release from regulatory control (clearance), for reuse in the nuclear industry or
as a commodity in general industry (e.g. concrete, rubble), or for disposal in a
disposal facility for non-radioactive waste.
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Guidance exists on how to derive and apply clearance levels.
Criteria: the effective dose to any individual due to the cleared material is of the
order of 10 μSv or less in a year
• Unconditional clearance – values derived considering all pathways, multiple scenarios
(Schedule I of the GSR Part 6)
• Specific (conditional clearance) – higher values derived case by case for specific
destination or reuse of the waste/material – some pathways and scenarios excluded,
need approval by the RB
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This topic was covered in the Workshop #9, Karlsruhe 2010
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Release of Buildings
• In general, a building can be released from regulatory control
when all radioactive materials have been removed to the
required level.
• How to deal with inactive buildings (e.g. office building) on a
licensed nuclear site?
• A reasonable approach may target at giving evidence of
clean buildings:
• Provide evidence that radionuclides were never used
• Provide evidence that contaminations did never occur
• Provide factual evidence by random / designated measurement on
the structures and by sampling
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Release of Buildings
• For contaminated buildings, which are planned to be reused
or demolished, the following actions are typically carried out:
• Decontaminate walls, ceilings, floors, as necessary;
• Remove (deep) contaminated equipment and materials, also along
fissures, cracks, joints etc.
• Prevent re-contamination after decontamination! (Protect surfaces)
• Clearance measurements on the existing structure
• Clearance of the rubble of a demolished building is possible,
but not the typical approach.
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Final Survey
• Cleanup actions completed
• Final survey plan approved as part of the
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decommissioning plan
Sampling equipment, instrumentation for
measurements and laboratory equipment
available
Procedures and trained personnel available
Radionuclides of concern known
Applicable site release levels known
Categorization of areas based on
information on spills / contamination
Determination of boundaries of survey and
survey units
Selection of background areas, if needed
Reference coordinate system
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Final Survey
• Direct measurements and/or sampling
• Determination of sampling locations
• Sampling equipment
• Sampling technique / Sample size
• Analysis / Measurement
• In case of contamination: increase density of grid / additional samples
• Measurement Uncertainty
o The radionuclide vector will inevitably differ slightly from the initial
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radionuclide vector
Monitoring techniques (e.g. emission probabilities in complex spectra, selfabsorption, scan speed and detector size in case of field measurements)
Sampling variation
Analytical process imprecision
Background variability
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• Comparison to the derived site release criteria
• Prepare a final survey report (part of the final decommissioning report)
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Final Survey
• Extensive information on the
final survey will be provided in
the other presentations during
this workshop.
• Detailed information is also
available in the IAEA SRS 72
(2012).
• In that publication the terms
‘remediation’ and ‘remedial
cleanup’ are used for what is
called ‘cleanup’ in this
presentation and in the IAEA
WS-G-5.1.
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Unrestricted / Restricted Use after Release
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After completing the cleanup activities, the operator should submit a final survey
report to the RB, demonstrating that the site release criteria have been met.
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The regulatory body should review the operator’s demonstration, confirm
compliance with the criteria and release the site from regulatory control.
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If the site complies with the appropriate release criteria when a reasonable set of
potential future uses and associated uncertainties have been considered, the site
should be released by the RB for unrestricted use, which is the preferred option.
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The decommissioning phase should then be terminated and the RB does not
need further involvement beyond keeping records about the site.
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If after cleanup the site does not meet the release criteria, it can be considered
for additional cleanup actions or for restricted use.
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The release of sites for restricted use generally requires ongoing institutional
involvement and control to implement the restrictions.
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The type, extent and duration of the restrictions and controls needed should be
proposed by the operator and approved by the RB.
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Unrestricted / Restricted Use after Release
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The restrictions should be proposed by the operator on the basis of a graded
approach and in consideration of factors such as the type and level of residual
contamination after the completion of cleanup, the relevant dose constraints and
release criteria, and the human and financial resources needed to implement the
restrictions and controls.
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The restrictions should be designed and implemented to provide a reasonable
assurance of compliance with the dose constraints. They should exclude or
prevent exposure pathways leading to effective doses higher than the dose
constraint (prohibit reuse for agricultural purposes, restrict access to the site).
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The restrictions should be enforceable by the RB and it should be specified which
organization will ensure that the restrictions are maintained.
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There may be limits prescribed on the time frames for institutional control - these
should be taken into consideration in deciding whether it is appropriate and
reasonable to release a site for restricted use.
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In addition, the way in which the restrictions would be removed in the future,
when they are no longer necessary, should be specified.
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Unrestricted / Restricted Use after Release
• When the objectives of the site release have been accomplished to the
satisfaction of the RB, the RB should formally notify the operator, other
relevant competent authorities and interested parties of the decision to
release the site from regulatory control.
• In the event of a decision for restricted use, the notification should
specify:
• the restrictive measures to be applied;
• their associated time frames;
• the entities responsible for the implementation, monitoring and control
of these restrictions.
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Summary
• Release of a site is the final step in decommissioning
processes and aims at termination of the license for
decommissioning. It is an authorized activity.
• Release of sites typically involves the following steps:
• Site characterization by the operator
• Definition of the release criteria – prescribed by the RB or
proposed by the operator and approved by the RB
• Planning of the cleanup actions by the operator (review and
approval by the RB)
• Conduct of the cleanup actions by the operator (oversight by
the RB)
• Planning of the final survey by the operator (review and
approval by the RB)
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Summary
• Conduct of the final survey by the operator (oversight by the RB)
• Preparation of a final survey report by the operator to
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demonstrate compliance with the release criteria, submission to
the RB
Review by the RB, independent confirmatory survey by the RB
Formal decision by the RB on unrestricted or restricted release
In case of restricted release, this decision includes
• definition of restrictions
• their duration
• responsibilities for their implementation
An effective record management system for the released sites
needs to be in place and to be maintained for future users of the
sites.
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Relevant IAEA Publications
Safety Requirements
• Decommissioning of Facilities, IAEA Safety Standards Series No. GSR
Part 6, IAEA, Vienna (2014).
• Radiation Protection and Safety of Radiation Sources: International Basic
Safety Standards, IAEA Safety Standards Series No. GSR Part 3, IAEA,
Vienna (2014).
Safety Guides
• Decommissioning of Nuclear Power Plants, Research Reactors and
Other Nuclear Fuel Cycle Facilities, Draft Safety Guide DS452, under
preparation, revision of the WS-G-2.1 and WS-G-2.4
• Application of the Concepts of Exclusion, Exemption and Clearance,
IAEA Safety Standards Series No. RS-G-1.7, IAEA, Vienna (2004).
• Release of Site from Regulatory Control Upon Termination of Practices,
IAEA Safety Standards Series No. WS-G-5.1, IAEA, Vienna (2006).
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Relevant IAEA Publications
Safety Reports
• Standard Format and Content for Safety Related Decommissioning
Documents, IAEA Safety Reports Series No. 45, IAEA, Vienna (2005).
• Derivation of Activity Concentration Values for Exclusion, Exemption and
Clearance, IAEA Safety Reports Series No. 44, IAEA, Vienna (2005).
• Monitoring for Compliance with Exemption and Clearance Levels, IAEA
Safety Reports Series No. 67, IAEA, Vienna (2012).
• Monitoring for Compliance with Remediation Criteria for Sites, IAEA
Safety Reports Series No. 72, IAEA, Vienna (2012).
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Relevant IAEA Publications
Nuclear Energy Series and Technical Reports
• Managing Low Radioactivity Material from the Decommissioning of
Nuclear Facilities, IAEA Technical Reports Series No. 462, IAEA, Vienna
(2008).
• Determination and Use of Scaling Factors for Waste Characterisation in
Nuclear Power Plants, IAEA Nuclear Energy Series No. NW-T-1.8, IAEA,
Vienna (2009).
• Long Term Preservation of Information for Decommissioning Projects,
IAEA Technical Reports Series No. 467, IAEA, Vienna (2008).
• An Overview of Stakeholder Involvement in Decommissioning, IAEA
Nuclear Energy Series NW-T-2.5, IAEA, Vienna (2009).
• E-versions available free of charge on the IAEA publications web pages:
http://www-pub.iaea.org/books/IAEABooks/Serial_Publications
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SUPPLEMENTARY SLIDES
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Exposure Situations (GSR Part 3)
• Planned exposure situation - exposure that arises from the planned
operation of a source or from a planned activity that results in an
exposure due to a source.
• Exposure at some level can be expected to occur. If exposure is not expected
to occur with certainty, but could result from an accident / event / sequence of
events that may occur, this is referred to as ‘potential exposure’.
• Emergency exposure situation - exposure that arises as a result of an
accident, a malicious act or any other unexpected event, and requires
prompt action in order to avoid or to reduce adverse consequences.
• Existing exposure situation - exposure that already exists when a
decision on the need for control needs to be taken.
• Includes situations of exposure to natural background radiation, exposure due
to residual radioactive material from past practices that were not subject to
regulatory control or exposure that remains after an emergency exposure
situation.
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Exposure Situations (GSR Part 3)
• Decommissioning is considered a planned exposure situation.
• All the activities prior to termination of the authorization (licence)
for decommissioning fall under the planned exposure situations.
• Example of an existing exposure situation is a remediation of a
contaminated land outside of a licensed site.
• Dose constraints and reference levels are used for optimization
of protection and safety.
• Dose constraints are applied to occupational exposure and to
public exposure in planned exposure situations.
• Reference levels are used for optimization of protection and safety
in emergency exposure situations and in existing exposure
situations.
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Concept of Exclusion
• Exclusion - any exposure whose magnitude or likelihood is
essentially not amenable to regulatory control and is
deemed to be excluded from standards / legal framework
• K40 in the human body
• Cosmic radiation at the surface of the Earth and terrestrial
radiation
• Fallout from atmospheric weapons testing
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Concept of Exemption
• Exemption - Practices and sources within a practice may
be, a priori, exempted from the requirements of standards
(not from legal framework) if exposures or risks will be
sufficiently small (trivial) or regulatory control of the practice
or the source would yield no net benefit.
• Based on the 10 Sv/y criteria (1 mSv/y for low probability
scenarios)
• Need to specify quantitative criteria – nuclide specific total
activity or activity concentration, amounts of material
• Tables I.1 (moderate amounts) and I.2 (bulk amounts) of the IAEA
GSR Part 3
• Justify practice (more overall benefit than detriment)
IAEA
Concept of Clearance
• Clearance - Removal of radioactive materials or objects
from within authorised practices without any further control
by the regulatory authority
• Radiation risks arising from the cleared material are
•
•
•
•
sufficiently low (order of 10 Sv/y criteria)
Continued regulatory control of the material would yield no
net benefit
Trivial amounts of radionuclide / trivial exposures
Clearance levels shall not be higher than exemption levels
Clearance of bulk amounts of material may require
particular regulatory consideration
IAEA
Concepts - Summary
• Excluded and exempt materials do not enter the nuclear
regulatory regime. They remain outside of regulated
practices.
• Cleared materials are released from within the nuclear
regulatory regime to outside of regulated practices.
• The government or the regulatory body shall determine
which practices or sources within practices are to be
exempted from some or all of the requirements of these
Standards.
• The regulatory body shall approve which sources, including
materials and objects, within notified practices or authorized
practices may be cleared from regulatory control.
IAEA
Regulatory Control of Radioactive Material
Authorized
Discharge
Exclusion
Authorized
Disposal
Radioactive
Material
Regulatory
Control
Clearance
Release of sites
Exemption
IAEA