International Atomic Energy Agency IX.4.5. Control of effluents Approach to regulatory control, establishing authorized discharge levels

International Atomic Energy Agency

IX.4.5.IX.4.5.Control of effluentsControl of effluents

Approach to regulatory control,establishing authorized discharge levels


OverviewOverview

• Basis for regulatory control of discharges

• Responsibilities of the regulatory body and of registrants and licensees

• Derivation of discharge limits

• Impact assessment

• Optimization

• Monitoring

• Form of discharge authorization


References (1)References (1)

• Regulatory Control of Discharges to the Environment, WS-G-2.3

• Ethical Considerations in Protecting the Environment from the Effects of Ionizing Radiation, TECDOC 1270

• Generic Models for Use in Assessing the Impact of Discharges of Radioactive Substances to the Environment, Safety Report Series No. 19

• Principles of Radioactive Waste Management, Safety Series No. 111-F


References (2)References (2)

• Recommendations of the ICRP

• ICRP 60

• ICRP 77

• International Basic Safety Standards for Protection Against Ionizing Radiation and safety of Radiation Sources, IAEA Safety Standards Series 115

• Protection of the Environment from the Effects of Ionizing Radiation: A Report for Discussion, IAEA TECDOC 1091


DischargesDischarges

• Discharges to the environment of radioactive substances in the form of airborne (gases, aerosols) or liquid effluents

• Discharge: ongoing or anticipated releases of radionuclides arising from the normal operation of a practice or a source within a practice.

• Discharges not considered:• underground injection of liquid radioactive substances

• releases arising from accidents

• discharges from uranium mining and milling facilities

• discharges from the disposal of solid radioactive waste


Principles ofPrinciples ofradioactive waste managementradioactive waste management

• Principle 1: Protection of human health“Radioactive waste shall be managed in such a way as to secure an acceptable level of protection for human health.”

• Principle 2: Protection of the environment“Radioactive waste shall be managed in such a way as to provide an acceptable level of protection of the environment.”


Spatial dose commitmentSpatial dose commitment

• Principle 3 of the Waste Safety Fundamentals states:

“Radioactive waste shall be managed in such a way as to assure that possible effects on human health and the environment beyond national borders will be taken into account.”

• Trans-boundary effects may occur through airborne or liquid discharges into bodies of water such as rivers or seas


Temporal dose commitmentTemporal dose commitment

• Principle 4 of the Waste Safety Fundamentals states that:

“Radioactive waste shall be managed in such a way that predicted impacts on the health of future generations will not be greater than relevant levels of impact that are acceptable today.”

• Has to be taken into account by• setting an appropriate dose constraint

• ensuring that the buildup of long lived radionuclides in the environment is given due consideration


Environmental protection Environmental protection

• ICRP 60: “The Commission believes that the standard of environmental control needed to protect man to the degree desirable will ensure that other species are not put at risk…”

• Guidance on protecting the environment from ionizing radiation is being developed by international organizations, including the IAEA and ICRP


Principle of waste minimizationPrinciple of waste minimization

• Waste should not be created unnecessarily

• Waste minimization to be considered in any optimization assessment

• Addresses solid, liquid and gaseous wastes, both together and separately

• Reduction in both activity concentration and volume of waste


Responsibilities of Responsibilities of the Regulatory Body (1)the Regulatory Body (1)

• The BSS “are based…on the presumption that a national infrastructure is in place enabling the Government to discharge its responsibilities for radiation protection and safety”

• Well defined powers of the inspectors of the regulatory body required

• Consistency of enforcement has to be maintained, with provision for appeal by those responsible for the discharge of radioactive effluents


Responsibilities ofResponsibilities ofthe Regulatory Body (2)the Regulatory Body (2)

• Functions of the regulatory body include: • preparation of regulations

• review of applications to discharge radioactive materials to the environment

• approval or rejection of these applications and the granting of authorizations

• the conduct of periodic inspections to verify compliance

• enforcement against any violations of regulations, standards and license conditions

• Effectiveness of radiation protection measures for each authorized discharge has to be assessed


Responsibilities of Responsibilities of the Regulatory Body (3)the Regulatory Body (3)

• There are circumstances in which notification (and therefore also authorization) is not required: • exposures may be excluded, and

• practices or sources may be exempted from the regulatory requirements

• Exemption of a practice or source covers all discharges of radionuclides from that practice or source


Notification vs. AuthorizationNotification vs. Authorization

• Notification is sufficient:• normal exposures are unlikely to exceed a small

fraction, specified by the regulatory body, of the relevant limitations,

• likelihood and expected amount of potential exposure and any other detrimental consequences are negligible

• For practices or sources involving a more significant risk, a formal authorization by the regulatory body is required


Application for authorizationApplication for authorization

• The application should contain an assessment of:• the nature of the discharge

• magnitude and likelihood of the exposures attributed to the discharges and

• when required, an appropriate safety assessment, including an explanation of how radiological protection has been optimized

• Information should be submitted prior to the commencement of the practice and its discharges


Responsibilities Responsibilities of Registrants and Licenseesof Registrants and Licensees

• Keep all radioactive discharges as far below authorized levels as is reasonably achievable

• Report promptly to the regulatory body any releases exceeding any reporting levels or authorized discharge

• Review discharges and their associated control measures at regular intervals in the light of operating experience

• Review implications of any changes in exposure pathways and of any changes in the composition of critical groups that would affect calculated doses


Monitoring programmesMonitoring programmes

• Registrants and licensees should, where appropriate, carry out monitoring programmes for effluents and environmental radiation

• Monitoring programmes should:• ensure that the requirements established by the

regulatory body are satisfied

• ensure that the assumptions about conditions in deriving the authorized discharge limitations remain valid

• enable exposures to critical groups to be assessed with an appropriate degree of confidence


Discharge limitations Discharge limitations

• Limitations are determined such that the requirements for optimization of protection and compliance with the dose constraints are satisfied

• Limitations are usually applied at the points of release

• Limitations on non-radioactive contaminants also relevant

• The assessment methodology could be:• generic or

• realistic (site specific)


Development of discharge Development of discharge limitationslimitations

• Scenario analysis followed by impact assessment to yield postulated doses

• Comparison of postulated dose with dose constraint

• No authorization if doses exceed the applicable dose constraint (possible exceptions for existing facilities)

• Optimization of the discharge levels taking due account of ALARA, BAT etc.

• Consideration of the need for operational flexibility

• Formalization of the discharge limitations and associated conditions of authorization, including the needs for compliance assurance


Impact assessment (1)Impact assessment (1)

Dose estimates:• Scenario analyses in which the release and

transport of radioactive pollutants are assessed quantitatively

• Dose assessment in which the radiological impacts of releases are calculated using mathematical models

• Important: the facility and its environment must be assessed as a system

• Comparison to regulatory criteria

• Iterative process


Impact assessment (2)Impact assessment (2)

Define radionuclide source term of the environmental discharge, including:

• Radionuclide composition

• Chemical and physical form

• Mode of release (liquid or gaseous)

• Release characteristics (e.g stack height, exit velocity, exit temperature, maximum and average release rates)

• Uncertainty can be reduced through further assessment and comparison with existing good practice and previous experience.


Characterization Characterization of source term and scenariosof source term and scenarios

• Characterization of source term:• For installations using unsealed sources (e.g.hospitals,

research laboratories) discharges can be assessed on the basis of the estimated throughput

• For nuclear installations (e.g. power reactors, nuclear fuel cycle facilities) estimates are based on considerations of design and operating characteristics

• Definition of release scenarios and pathways and the probability of occurrence of each scenario

• Scenarios limited to normal operation and do not extend to cover accident scenarios


Generic safety assessments (1)Generic safety assessments (1)

• Generic safety assessments used to establish numerical criteria that can be used at all sites

• Conservative assumptions used to give some assurance that the regulatory criteria will be met

• Advantages:• Provides clear requirements to both the regulator and

the licensee

• Similar technical solutions can be applied to all facilities

• Easier and less costly than site-specific assessments


Generic safety assessments (2)Generic safety assessments (2)

• Disadvantages of generic safety assessments • requirements may be more stringent than those

needed for a site having characteristics that are more favorable than those of the generic model

• precludes detailed optimization

• Particularly useful for assessing the impacts from small-scale facilities

• For larger scale nuclear facilities usually more detailed site-specific assessment are needed


Site-specific assessments Site-specific assessments

• The site-specific methodology assesses the actual impact associated with releases from a site

• More complex than a generic assessment

• Allows for the development of specific controls to demonstrate compliance with regulatory criteria

• Specific risks are quantified and an optimum option can be selected taking account of the actual releases on a nuclide specific basis

• In cases where there is large variation in site-specific parameters this may be the only option


Optimization (1)Optimization (1)

• Optimization considerations:• evaluation of the costs and efficacies of available

control options and of the possibility of changing the process to minimized discharges

• not all options will require a formal optimization assessment, avoiding spending resources to assess options for reducing discharges in disproportion to the likely improvement in radiological protection



• Formal optimization involves consideration of various management options and their features, such as• capital, operating and maintenance costs

• implications for waste management including discharges

• effect on individual and collective doses for public and workers

• Several management options are likely to be considered when assessing optimization



• New facilities: optimization through design, construction, operation, and decommissioning stages of the facility

• Existing facility: fewer options available to optimize

• Control measures will most likely be either storage (for decay) or treatment (radionuclide removal)

• Optimal control method will be dependent on the waste stream and the radionuclides involved

• To be considered: effect of control measures on occupational doses


CostsCosts

• Capital, operational and maintenance costs to be taken into account in decision about management option

• Costs incurred should be commensurate to hazard, no unnecessary arrangements for practices posing low risk

• Regulation should be focused on the major problem, and therefore targeting costs where they will have most effect


Stakeholder involvementStakeholder involvement

• Public consultation is required in several Member States, usually involves local and regional groups (particularly for nuclear installations)

• Benefits and risks to be discussed

• Aiming at openness and transparency

• Decision will only be widely accepted if a good balance is seen between costs of reduction and residual radiological impact


Discharge authorizationDischarge authorization

• Authorized discharge limitations are “not to be exceeded” values (otherwise, enforcement action and penalties)

• Setting authorized discharges at optimized levels: frequent occurrence of violations of regulatory requirements

• To avoid this, leave ‘head room’; definition requires judgement - as a minimum it must allow for anticipated operating events


Forms of discharge authorization (1)Forms of discharge authorization (1)

• Basic interval over which compliance is expected to be shown is usually one year

• Additional limitations for shorter periods (allowing for a closer performance monitoring and to take action if performance fails to meet the short term limitations)

• Short term limitations generally higher than the applicable fraction of the annual limitation to allow for operational flexibility (e.g. half of the annual limit within a calendar quarter, 30-50 times the average rate for instantaneous releases)



• Quantity to be limited and controlled could be• dose incurred by releases

• activity released from the site (specified usually at the point of release, such as the stack or the discharge pipe)

• Both quantities are proportional for a given site

• Dose is more fundamental and easier understood by the public (but still has to be assessed from activity released)

• Limitations in terms of quantities discharged reflect more closely• the quantity that is to be controlled and measured

• the actions to control the discharges.



• Discharge limitations have to be specified for the whole site, possible additional limitations for individual units

• Sole use of site discharge limitations is simpler, but may cause single units to operate at a higher discharge level than optimal

• Site limitation may require adaptation if additional units are built

• Simple operations: discharge limitations may be set indirectly by using an operating parameter that directly determines the levels of discharge


Period of validity Period of validity

• Discharge authorization: limited period of validity

• At the end of this period the authorization must be • reviewed

• updated if necessary

• re-issued

• No standard period of validity (varies from two to five or more years)

• Basis: Judgment by the regulatory authority of the likelihood of changes at the site or in its environment


SummarySummary

• Discharges have to be addressed within an adequate regulatory process (regulations, notification or authorization requirements, monitoring, enforcement)

• Basis for discharge limitations (impact assessment, either generic or site-specific)

• Discharges have to be in compliance with dose constraints

• Optimization of discharges based on available control options, costs and other relevant factors

Documents

International Atomic Energy Agency IX.4.5. Control of effluents Approach to regulatory control, establishing authorized discharge levels