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IAEA International Atomic Energy Agency Radioactive Waste Arising, Waste Classification, and Safety Requirements for Waste Disposal Day 9 – Lecture 6.

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Presentation on theme: "IAEA International Atomic Energy Agency Radioactive Waste Arising, Waste Classification, and Safety Requirements for Waste Disposal Day 9 – Lecture 6."— Presentation transcript:

1 IAEA International Atomic Energy Agency Radioactive Waste Arising, Waste Classification, and Safety Requirements for Waste Disposal Day 9 – Lecture 6

2 IAEA To provide an overview of radioactive waste arising and classification, waste characteristics and management options. To introduce the IAEA waste classification system. To discuss about the requirements for the protection of public and environment and assurance of safety for the waste disposal facilities during the operational and post-closure period To give examples of final disposal choices Objectives 2

3 IAEA Sources of Radioactive Waste Waste Properties. Waste Management Approaches Waste classification IAEA Waste Classification System Waste Disposal Options Requirements for protection of public and environment and safety of waste disposal facilities Contents 3

4 IAEA Introduction Radioactive waste arises from many different activities, for example: Operation and decommissioning of nuclear facilities (e.g. nuclear power plants); Application of radionuclides in industry, medicine, and research; Cleanup of contaminated sites; and Processing of raw materials containing naturally occurring radionuclides. 4

5 IAEA Nuclear fuel cycle - Power generation Operational waste  Ion exchange resins, evaporation and filtering residues  Metal scrap, thermal insulation material, protective clothing  Very low to medium level concentrations of RN Spent nuclear fuel  Large inventory, large number of radionuclides Decommissioning waste  Large amounts  Very low to high concentrations - mainly activation products Sources of Radioactive Waste (1) 5

6 IAEA Nuclear fuel cycle - Various Mining and milling and U ore extraction – Large quantities – Enhanced levels naturally occurring radionuclides – Radium-226, radon-222 Chemical refining – small amounts of waste Enrichment – depleted uranium a waste? Reprocessing of spent fuel. Sources of Radioactive Waste (2) 6

7 IAEA Sources of Radioactive Waste (3) Industrial applications Production of radioactive sources Use of radioactive sources Sealed sources Thickness, level and density gauges Industrial radiography, sterilization facilities Large number of potentially hazardous sources Unsealed sources Tracers, monitoring Mostly short-lived radionuclides Co-60, Cs-137, Ir-192, Am-241,… 7

8 IAEA Sources of Radioactive Waste (4) Medical applications Diagnosis and treatment Large number of administrations and operations Short-lived liquid and solid waste Large activity administrations High-activity sealed sources Tc-99m, I-131, P-32, Y-90, Sr-89 Co-60, Ir-192, Cs-137 8

9 IAEA Sources of Radioactive Waste (5) Research and development Wide variety of uses Wide variety of techniques Other: historical sources - radium processing defense programs – legacy wastes 9

10 IAEA Sources of Radioactive Waste (6) Wastes containing naturally occurring radioactivity (NORM) Phosphate industry Production of metals Refractory materials Energy Production (Oil and Gas, Coal, Biomass, Geothermal) Usually large volumes, Ra-226, Rn-222 10

11 IAEA Pre-treatment Treatment Conditioning Disposal Recycling and re-use Effluent discharge Clearance Waste and materials Waste Management Approaches 11

12 IAEA Waste Management Approaches ‘ Delay and Decay’ – hold waste in storage until sufficient decay has occurred for desired management approach ‘Concentrate and Contain’ – reduce volume and condition and/or containerize waste to limit dispersion in the environment ‘Dilute and Disperse’ – discharge waste in a manner that environmental conditions reduce concentrations to acceptable levels 12

13 IAEA Waste classification - Purpose Purpose - for safety, engineering, operational and regulatory aspects: Devising radioactive waste management strategies, planning, designing and operating waste management facilities; Facilitating record keeping and giving a broad indication of the potential hazards involved in the various types of waste at the operational level; Communication between interested parties by providing well understood terminology (e.g., Joint Convention) 13

14 IAEA Possible ways to classify Some of the possible ways to classify waste: Classification by origin Nuclear fuel cycle, isotope production,.. Classification by physical state Solid, liquid, gaseous Classification by activity concentration Very Low Level waste (VLLW), Low Level Waste (LLW), Intermediate Level Waste (ILW), High level Waste (HLW) Classification by half-life Short-lived waste, long-lived waste 14

15 IAEA Need for a classification system? Permits appropriate decisions to be made at each step of lifecycle management of wastes. Provides a systematic foundation for waste segregation programmes. Efficient management system for operators (otherwise decisions are ad hoc or made on case by case basis). Provides essential input for national WM policy & strategy. 15

16 IAEA Summary of IAEA Waste Classification System (GSG-1) Objectives To set out a general scheme for classifying radioactive waste that is based primarily on considerations of long term safety, and thus, by implication, disposal of the waste. To identify the conceptual boundaries between different classes of waste and provides guidance on their definition on the basis of long term safety considerations. 16

17 IAEA Summary of IAEA System GSG - 1 The IAEA system (1)Exempt waste (2) Very short lived waste (VSLW) (3) Very low level waste (VLLW) (4) Low level waste (LLW) (5) Intermediate level waste (ILW) (6) High level waste (HLW) 17

18 IAEA Summary of IAEA System GSG - 1 In the classification scheme, the following options for management of radioactive waste are considered, with an increasing degree of containment and isolation in the long term: —Exemption or clearance; —Storage for decay; —Disposal in engineered surface landfill type facilities; —Disposal in engineered facilities such as trenches, vaults or shallow boreholes, at the surface or at depths down to a few tens of metres; —Disposal in engineered facilities at intermediate depths between a few tens of metres and several hundred metres (including existing caverns) and disposal in boreholes of small diameter; —Disposal in engineered facilities located in deep stable geological formations at depths of a few hundred metres or more. 18

19 IAEA Waste that has been cleared, exempted or excluded from regulation as described in Safety Guide RS-G-1.7 “Application of the Concepts of Exclusion, Exemption and Clearance” (2004) Exempt Waste (EW) 19

20 IAEA Waste containing material that can be slightly above the exempt region. Disposal facilities for such waste do not need a high level of containment and isolation and near surface landfill is generally suitable. Typical waste would include soil and rubble with activity low enough not to require shielding. Very Low Level Waste (VLLW) 20

21 IAEA Waste that can be stored for decay over a limited period of up to a few years and subsequently cleared for uncontrolled disposal or discharge after a suitable period of storage. This would include radioactive waste containing short half life radionuclides typically used for research and medical purposes. Very Short Lived Waste (VSLW) 21

22 IAEA Waste that contains material with radionuclide content above clearance levels, but with limited amounts of long lived activity. It requires robust isolation and containing for periods of up to a few hundred years typically 300. It includes a very broad band of materials that includes very high activity waste with short half life that requires shielding and some long lived material at relatively low activity levels. Such waste would require up to around 300 years of control but would not be hazardous beyond that period of time. The radionuclides within the waste will decay to activity levels that are acceptably low from a radiological safety viewpoint, within a time period during which institutional controls can be relied upon. Low Level Waste (LLW) 22

23 IAEA Waste which, because of its high radionuclide content and the potential mobility of the materials involved requires a higher level of containment and isolation than is provided by near surface disposal. However, needs little or no provision for heat dissipation during its handling, transportation and disposal. It may include long lived waste that will not decay to an acceptable activity level during the time which institutional controls can be relied upon. Intermediate level waste (ILW) 23

24 IAEA Waste with radioactivity levels intense enough to generate significant quantities of heat by the radioactive decay process or with large amounts of long lived activity which need to be considered in the design of a disposal facility for the waste. Disposal in deep, stable geological formations is the preferred option for its disposal. It includes spent reactor fuel which has been declared as waste, vitrified waste from the processing of reactor fuel and any other waste requiring the degree of containment and isolation provided by geological disposal. High Level Waste (HLW) 24

25 IAEA Half-life Activity content VSLW very short lived waste (decay storage) HLW high level waste (deep geologic disposal) ILW intermediate level waste (intermediate depth disposal ) LLW low level waste (near surface disposal) VLLW very low level waste (landfill disposal) EW exempt waste (exemption / clearance ) Geological Intermediate Near surface Landfill Clearance IAEA Waste Classification System (2009) 25

26 IAEA Classification as Practiced Many member states still use their own system, customized to fit local needs. Disposal endpoint is what is most commonly used to define waste classes. As part of Joint Convention, each country reports on national system of waste classification and reports a national inventory of radioactive waste. 26

27 IAEA Waste Disposal Options Surface Disposal Surface Discharge Geological Disposal Well injection Near-Surface Disposal 27

28 IAEA Selection of Management Options Selected options must be consistent with National policies for waste management; Need to consider interdependencies with other predisposal and final disposal options; Adequate characterization of waste is critical. 28

29 IAEA Safe Disposal of Radioactive Waste The fundamental safety objective is to protect people and the environment from harmful effects of ionizing radiation To achieve this objective this publication sets out requirements on the site selection and evaluation and design of a disposal facility, and on its construction, operation and closure, including organizational and regulatory requirements To achieve this objective this publication sets out requirements on the site selection and evaluation and design of a disposal facility, and on its construction, operation and closure, including organizational and regulatory requirements Objective/Scope of IAEA Publication SSR-5 29

30 IAEA Disposal The term ‘disposal’ refers to the emplacement of radioactive waste into a facility or a location with no intention of retrieving the waste. (The term disposal implies that retrieval is not intended; it does not mean that retrieval is not possible.) Disposal options are designed to contain the waste by means of passive engineered and natural features and isolate it from the accessible biosphere to the extent necessitated by the associated hazard. 30

31 IAEA W A S T E W A S T E BIOSPHREBIOSPHRE BIOSPHREBIOSPHRE CONTAIN ISOLATE INHIBIT, REDUCE, DELAY SOURCE SAFETY FUNCTIONS RECEIPIENT OBJECTIVE ACCEPTABLY LOW IMPACT The specific aims of disposal: to contain the waste; to isolate the waste from the accessible biosphere and to substantially reduce the likelihood of and all possible consequences of inadvertent human intrusion into the waste; to inhibit, reduce and delay the migration of radionuclides at any time from the waste to the accessible biosphere. to ensure that the amounts of radionuclides reaching the accessible biosphere due to any migration from the disposal facility are such that possible radiological consequences are acceptably low at all times. 31

32 IAEA Specific landfill disposal Near surface disposal Disposal of intermediate level waste Geological disposal Borehole disposal Disposal of mining and minerals processing waste Safety Guides provide comprehensive guidance on and international best practices for meeting the requirements in respect of different types of disposal facility. Safety Requirements applies to all of the types of disposal and disposal facilities 32

33 IAEA Protection of people and the environment (1) The IAEA Safety Fundamentals publication Fundamentall Safety Principles sets out the fundamental safety objective and safety principles that apply for all facilities and activities in radioactive waste management, including the disposal of radioactive waste. The ICRP developed a System of Radiological Protection that applies to all facilities and activities, and this system was adopted in the International Basic Safety Standards. The ICRP has elaborated the application of the System of Radiological Protection to the disposal of solid radioactive waste in its Publications 77 and 81 which it reconfirmed in Publication 103. This provides a starting point for the safety considerations relation to disposal facilities. 33

34 IAEA Protection of people and the environment (2) Radiation protection in the operational period The radiation safety requirements and the related safety criteria for the operational period of a disposal facility are the same as for any nuclear facility or activity involving radioactive material, and are established in the GSR part 3. In radiological protection terms, the disposal facility is considered to be a source of radiation that is under regulatory control in a planned exposure situation. Expect no significant releases of radioactivity during the operational period; no doses to public The primary goal is to ensure that radiation doses are as low as reasonably achievable (ALARA) and within the applicable system of dose limitation. 34

35 IAEA Protection of people and the environment (3) Post Closure Safety Criteria Safety objective: A reasonable assurance has to be provided that doses and risks to members of the public in the long term will not exceed the dose constraints or risk constraints that were used as design criteria. The dose limit for members of the public from all planned exposure situations is an effective dose of 1 mSv in a year, and this or its risk equivalent are considered criteria not to be exceeded in the future. To comply with this dose limit, a disposal facility is designed so that the estimated dose or risk to the representative person who may be exposed in the future as a result of natural processes affecting the disposal facility does not exceed a dose constraint of 0.3 mSv in a year or a risk constraint of the order of 10 -5 per year. (Risk due to the disposal facility in this context is to be understood as the probability of fatal cancer or serious hereditary effects.) 35

36 IAEA If such intrusion is expected to lead to an annual dose of less than 1 mSv per year to those living around the site, efforts to reduce the probability of human intrusion or to limit its consequences are not warranted. If HI is expected to lead to an annual dose of more than 20 mSv per year to those living around the site, alternative disposal options are to be considered, for example disposal of the waste below the surface, or separation of the radionuclide content giving rise to the higher dose. If annual doses in the range 1 – 20 mSv are indicated, reasonable efforts are justified at the facility development stage to reduce the probability of intrusion or to limit its consequences by optimization of the facility design. < 1 mSv Measures not warranted > 20 mSv Alternative disposal 1 – 20 mSv Measures considered Inadvertent human intrusion in the post- closure period 36

37 IAEA Protection of people and the environment (4) Environmental and non-radiological concerns The scope of safety requirements for disposal of radioactive waste is the protection of the environment against radiological hazards associated with the radioactive material in the disposal facility. The assessment of conventional environmental impacts such as may occur in the construction and operational period for a disposal facility, e.g. impacts relating to traffic, noise, visual amenity, disturbance of natural habitats, restrictions on land use and social and economic factors, as well as non-radiological toxic hazard also has to be assessed where this is significant. If non-radioactive materials may affect the release and migration of radioactive contaminants from the radioactive waste, then such interactions have to be considered in the SA. 37

38 IAEA In order to meet the basic objective, i.e., to ensure safety of waste disposal facilities, 26 requirements have been established in the IAEA publication SSR-5 Safety Requirements for safe disposal of Radioactive Waste 38

39 IAEA List of 26 requirements (1/2) 1. government responsibilities 2. regulatory body responsibilities 3. operator responsibilities 4. importance of safety in the development process 5. passive safety of the disposal facility 6. understanding of facility and for confidence in safety 7. multiple safety functions 8. Containment of radioactive waste 9. Isolation of radioactive waste 10. Surveillance and control of passive safety features 11. step by step development and evaluation of facilities 12. Preparation and use of the safety case and safety assessment 13. scope of the safety case and safety assessment 14. documentation of the safety case and safety assessment Safety Requirements for safe disposal of Radioactive Waste 39

40 IAEA List of 26 requirements (2/2) 15. site characterization of disposal facility 16. design of a disposal facility design 17. construction of a disposal facility 18. Operation of a disposal facility 19. closure of a disposal facility 20. waste acceptance in a disposal facility 21. monitoring programmes in a disposal facility 22. the period after closure and institutional controls 23. state system of accounting for, and control of, nuclear material 24. requirements in respect of nuclear security 25. management systems 26. existing disposal facilities Safety Requirements for safe disposal of Radioactive Waste 40

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