CONCEPTS OF EXCLUSION, EXEMPTION AND CLEARANCE

1. EXCLUSION, EXEMPTION AND CLEARANCE Daniela E. Alvarez, Ph.D.ARAB ATOMIC ENERGY AGENCY/ARAB NETWORK OF NUCLEAR REGULATORS (ANNuR)FORUM OF NUCLEAR REGULATORY BODIES IN AFRICA (FNRBA)Regional Workshop on Management and Safe Disposal of Radioactive WasteTunis, 17-21, March 2014

2. CONCEPTS OF EXCLUSION, EXEMPTION AND CLEARANCE The International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (BSS) specify requirements for the protection of health against exposure to ionizing radiation and for the safety of radiation sources. The BSS, which are based on information on the detrimental effects attributed to radiation exposure provided by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) as well as on the recommendations of the International Commission on Radiological Protection (ICRP), are intended to provide the basis for the regulation of both “practices” and “interventions” Humans incur radiation doses from exposure to radionuclides. Some radionuclides are “natural” (primordial or created by the continuous interaction of cosmic rays with the atmosphere) and others are “artificial”, which are produced and used in practices

3. CONCEPTS OF EXCLUSION, EXEMPTION AND CLEARANCE • Radioactivematerials of natural origin are present at theatmosphere, water, solids and living organisms: • Primordials, like K-40; U-238 (and itsfamily Ra-226; Rn-222); Th-232 (and itsfamily Ra-228; Rn-224) • Cosmogenics, like C-14 y H-3 • There are alsoradioactive material traces distributedglobally and regionally, like C-14; H-3; Tc-99; Cs-137 or Sr-90, commingfromthefall-out of nuclear explosions, accidents and evendischarges of effluents • WHITOUT A QUANTITATIVE DEFINITION, • EVERY MATERIAL IS RADIOACTIVE

4. In every practice with nuclear material it exists a: • Control of contaminated material • High concentrations of radioactive material require safe management • As concentrations become lower - need for control becomesless • At a sufficiently low concentration, controls are no longer necessary – • for health and safety reasons

5. EXCLUSION The IAEA Safety Guide No RS-G-1.7 states that: “Any exposure whose magnitude or likelihood is essentially unamenable to control through the requirements of the Standards is deemed to be excluded from the Standards” Then, exclusion relates to the susceptibility of exposure to regulatory control rather than to the actual magnitudes of exposures. Susceptibility to control is a relative concept that implies recognition of the cost of exercising regulatory control and the net benefit to be gained by so doing Basically: I can do nothing to diminish the exposure (natural RN)

6. EXEMPTION • Exemption can be defined as relief from the obligation to comply with a condition imposed by law or authorities. Consequently, the word "exemption" should never stand alone and one should always specify from which requirements or provisions there is exemption • MAIN CRITERIA • Radiation risks arising from the practice or a source within a practice are sufficiently low as not to warrant regulatory control • Regulatory control of the practice or the source would yield no net benefit

7. EXEMPTION • QUANTITATIVE CRITERIA • The primary radiological basis for establishing values of activity concentration for the exemption of bulk amounts of material and for clearance is that the effective doses to individuals should be of the order of 10 μSv or less in a year(trivial doses) • Additionally, occurrence of low probability events leading to higher radiation exposures have been considered and the effective doses should not exceed 1mSv in a year as well as anequivalent dose criterion of 50 mSv in a year to the skin was used

8. Accordingtothesecriteria, IAEA derived “exemptiongenericvalues” in ordertofacilitatetheapplication (RadiationProtection 65) • RADIONUCLIDE SELECTION • About 300 radionuclides were considered in this study. Their possible uses and their related physical forms were reviewed in consultation with European experts involved in advising small-scale users of radioactivity materials. About 100 of the radionuclides considered in the study were identified as currently having actual or potential uses. Each of these radionuclides was identified as being used in one or more of the following physical forms: gas/vapour, liquid/solution, dispersible solid (eg, powder), non dispersible solid, thin film/foil and sealed source/capsule. E.g.: • 85Kr supplied in sealed glass or metal containers: beta sources (in surface density gauges) or the gas may be used in the unsealed form (testing the integrity of some semiconductor devices) • radionuclides used in the form of liquid solutions (99mTc in diagnostic nuclear medicine and 32P in biochemical research) • sealedradioactivesources

9. SCENARIOS SELECTION The scope of this study was to consider the doses arising from the use, misuse and disposal of radioactive materials and then to compare the resulting doses with the appropriate dose criteria Three scenarios (normal use: workplace, accidental: workplace and disposal to landfill: public) and 24 exposure pathways were identified as the most relevant following consultation with European experts and a review of existing calculations Each of these scenarios gives rise to doses via one or more pathways and therefore the doses from the relevant pathways are summed to give a total dose from the scenario before comparing with the dose criteria All these scenarios are very conservatives and cover many possible situations

10. SCENARIOS SELECTION (cont.) • The Normal Use (workplace) scenario represents the use of small amounts of radionuclides in industry and involves external exposure and inadvertent intakes of radioactive materials. Exposures to the pubic arising from normal releases of activity are adequately covered by this workplace scenario • The Accidental (workplace) scenario represents abnormal procedures or incidents that might occur during the routine use of small amounts of radionuclides (spillage and fire). These situations may lead to exposures via a range of external, inhalation and ingestion pathways • The Disposal (public) scenario represents a member of the public becoming exposed after subsequent disposal of the source. This situation may lead to external, inhalation and ingestion pathways. Both normal and accidental situations are considered

11. Methodology for calculating exempt activities and activity concentrations

12. EXPOSURE SCENARIOS AND PATHWAYS ACTIVITY CONCENTRATION - Normal use (workplace) scenario: External exposure from handling a source External exposure from a 1 m3 source External exposure from a gas bottle Inhalation of dusts Ingestion from contaminated hands Spillage: External exposure from contaminated surface Spillage: Ingestion from hands Spillage: Inhalation of resuspended activity Spillage: External dose from aerosol or dust cloud Fire: Contamination of skin Fire: Inhalation of dust or volatiles Fire: External from combustion products - Disposal (public) scenario: External exposure from a landfill site Inhalation of dust from a landfill site Ingestion of an object from a landfill site - Disposal (public) scenario: External exposure from a landfill site Inhalation from a landfill site External exposure to skin from handling an object from a landfill site Ingestion of an object from a landfill site ACTIVITIES/QUANTITIES - Normal use (workplace) scenario: External exposure from a point source External exposure from handling a source - Accidental (workplace) scenario: Spillage: External exposure from contaminated hands Spillage. External exposure from contaminated face

13. EXEMPTION VALUES Exemption values were calculated using the dose criteria mentioned and dividing these by the maximum doses obtained for each scenario and radionuclide Annual individual dose criteria Exempt level for each RN and each scenario = Dose per unit activity (Bq) or activity concentration (Bq/g) The most restrictive exempt level for each radionuclide and waste form was determined from the two workplace scenarios and the public scenario. It is usual to present these values (activity and activity concentration) as a table together with the corresponding dominant pathway These values were rounded and called “generic exempt values” or “exempt values”. They have been adopted for mostly of Member States

14. EXEMPTION VALUES

15. MIXTURE OF RADIONUCLIDES For material containing a mixture of radionuclides of artificial origin, the following formula should be used to be sure that the material is exempt: n ∑ Ci ≤ 1 i=1 (activity concentration)i Where Ci is the activity concentration (Bq/g) of the ith radionuclide of artificial origin in the material, (activity concentration)i is the exemption value expressed as activity concentration for the radionuclide i in the material and n is the number of radionuclides present (NOTE: the same formula should be used if the information is the activity instead of activity concentration)

16. CLEARANCE MAIN CRITERIA • Radiation risks arising from the cleared material are sufficiently low as not to warrant regulatory control • Continued regulatory control of the material would yield no net benefit, in that no reasonable control measures would achieve a worthwhile return in terms of reduction of individual doses or of healthrisks QUANTITATIVE CRITERIA The same radiological criteria used for exemption is applicable for clearance

17. SCENARIOS SELECTION The sequence of calculations for deriving the activity concentration values for all material containing radionuclides of artificial origin, except foodstuffs and drinking water, is the same that exemption case but the scenarios considered are differents Scenario WL A worker is exposed from contaminated material dumped on a landfill Scenario WF A worker is employed in a foundry where contaminated metal is smelted Scenario WO A worker (e.g. a truck driver) comes into contact with contaminated material on a regular basis Scenarios RL-C and RL-A Scenario RL considers individuals living near a landfill or other facility (C indicates a child, A an adult) who are exposed through contaminated dust released at the landfill or facility Scenario RF A child being exposed to contaminated dust released by a foundry

18. SCENARIOS SELECTION Scenario RH Contaminated material (building rubble, slag, fly ash) may be used in the construction of buildings as concrete aggregate or cement substitute Scenario RP If contaminated material is used for covering public places, residents will be subject to exposures Scenario RW The presence of contaminated material may lead to a release of radionuclides in to a groundwater aquifer The identified (and conservatived) scenarios encompass all plausible situations worldwide without specifying a particular situation Clearance values from IAEA Safety Reports Series 44

20. APPLICATION • Thelevels, to compare withtheclearancevalues, must be estimatefromtheaverage of thedetermination of activityconcentration in the material understudy Theactivityconcentration can be determine by: • Directmeasurements • Usingactivityrelationspreviouslydetermined • Identification of thehistory of the material fromtheorigin • Laboratoryanalysis (complement of directmeasurements) • Theaverage of theactivityconcentrationisfunction of: • Type of material (considering superficial activityconcentration) • Segregation of material sincethegeneration, in ordertowarrant thehomogenization

21. APPLICATION Nevertheless, it could be possible that a material with activity concentrations higher than clearance values be clearanced by the Regulatory Body. In such case, usually a conditional clearance is used, which means that the material will be used for (and only for) a specific use. For example, use demolition materials for road constructions

22. Importance of Clearance Levels • Reduce the amount of material disposed as waste, thereby reducing cost - consistent with fundamental principles. If criteria are not established - resources will be wasted • ImpactsonNationalPolicy • Impacts on the amount of material to be disposed of have national repercussions • Absence of clearance criteria can affect the ability to complete decommissioning & perform cleanups • Inappropriate criteria can result in previously cleared material becoming the focus for further remediation

23. Application of the Concepts • • Decisions needed on how the values will be incorporatedintonationalregulations • • Decisions needed on how the values will be used to control clearance of materials • Dependind on the legal framework and nationalregulatorypractices

24. SUMMARIZING

25. Thank you