IAEA CLASSIFICATION OF RADIOACTIVE WASTE

Transcription

1 IAEA CLASSIFICATION OF RADIOACTIVE WASTE GERARD BRUNO Workshop on Clearance of Decommissioning Waste 6 9 November 2012, Bangkok, Thailand

2 Outline Overview of radioactive waste arising Waste management approaches Radioactive waste classification Examples of disposal options 2

3 Waste Arisings 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; Processing of raw materials containing naturally occurring radionuclides. 3

4 Waste Arisings (cont) 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 4

5 Waste Arisings (cont) 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 Reprocessing of spent fuel 5

6 Waste Arisings (cont) Industrial applications Production and use of radioactive sources Medical applications Diagnosis and treatment Research and development Wide variety of use and techniques Wastes containing naturally occurring radioactivity (NORM) E.g. phosphate industry, production of metals, oil and gas 6

7 Waste Arisings (cont) - Properties Origin/Source Criticality Radiological Properties half-life heat generation intensity of radiation nuclide conc. surface contamination dose factors Biological properties: potential biological hazards Chemical Properties potential chemical hazard combustible, corrosive organic content reactivity gas generation sorption of radionuclides Physical Properties compactability, incinerability dispersability, volatility solubility, miscibility physical state (solid, liquid, gas) size and weight 7

8 Waste Management Approaches Waste and materials Pre-treatment Effluent discharge Clearance Treatment Conditioning Recycling and re-use Disposal 8

9 Requirement 9: Characterization and classification of radioactive waste At various steps in the predisposal management of radioactive waste, the radioactive waste shall be characterized and classified in accordance with requirements established or approved by the regulatory body. Characterized in terms of its physical, mechanical, chemical, radiological and biological properties The characterization serves to provide information relevant to process control and assurance that the waste or waste package will meet the acceptance criteria for processing, storage, transport and disposal of the waste Classification has to be made from the perspective of its future disposal 9

10 Possible Ways to Classify Waste Possible ways to classify waste: Classification by origin Nuclear fuel cycle, isotope production,.. Classification by physical state Solid, liquid, gaseous Classification by activity concentration Low Level Waste (LLW), Intermediate Level Waste (ILW), High level Waste (HLW) Classification by half-life Short-lived waste, long-lived waste Operational or disposal purposes 10

11 11

12 HLW LILW EW 12

13 New IAEA Waste Classification supersedes

14 Objective of the classification 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 The proposed classification identifies the conceptual boundaries between different classes of waste and provides guidance on their definition on the basis of long term safety considerations Waste is classified according to the degree of containment and isolation required to ensure its safety in the long term, with consideration given to the hazard potential of different types of waste 14

15 Purpose of Waste Classification Safety, engineering and regulatory aspects: Radioactive waste management strategies, planning and designing 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) 15

16 WASTE TYPES & RELEVANT DISPOSAL OPTIONS VSLW VLLW LLW ILW HLW Activity, half-life

17 The Waste Classification Scheme Exempt waste (EW) Very low level waste (VLLW) Very short lived waste (VSLW) Low level waste (LLW) Intermediate level waste (ILW) High level waste (HLW) 17

18 Exempt Waste (EW) 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) 18

19 Very Low Level Waste (VLLW) 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.

20 Very Short Lived Waste (VSLW) 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. 20

21 Low Level Waste (LLW) Waste that contains material with radionuclide content above clearance levels, but with limited amounts of long lived activity. It requires robust isolation and containment for periods of up to a few hundred years and is suitable for disposal in engineered near surface facilities.

22 Intermediate level waste (ILW) 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. This class of waste requires disposal at greater depth, of the order of tens of m to a few hundred m

23 High Level Waste (HLW) Waste with radioactivity levels high 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.

24 Activity content HLW high level waste (deep geologic disposal) Geological VSLW very short lived waste (decay storage) LLW low level waste (near surface disposal) VLLW very low level waste (landfill disposal) ILW intermediate level waste (intermediate depth disposal) Intermediate Near surface Landfill EW exempt waste (exemption / clearance) Half-life Clearance 24

25 Increasing Levels of Containment and Isolation Exemption or clearance Storage for decay Above surface engineered landfill Near surface disposal trenches, vaults or shallow boreholes Engineered facilities at intermediate depth 10s to 100s of metres Geological disposal > few hundred metres 25

26 Broad Disposal Options Surface and near-surface disposal (with and without engineered barriers) up to 30m Underground cavities (natural or engineered) at few m to few 100 m (intermediate depth disposal) Geological disposal (a mined facility) several hundreds of m Borehole disposal

27 SCHEMATIC - OPTIONS 30 m A A 100 m B A B C on or near surface < 30 M intermediate depth deep disposal 100 s M 100s m C 27 5

28 Principle of a Step Wise Disposal Programme A disposal facility should be developed in a series of steps that are iterative and overlapping as necessary. Steps should progressively evaluate site conditions in greater detail, refine disposal facility design and assess operational and post-closure safety. Key decision points should be established for approvals to construct, operate and close a facility Current best-practice includes stakeholder engagement, including involvement of local communities 28

29 Preoperational Operational Post-closure Construction License Operational License End of disposal operations Start of institutional control End of repository life-cycle Closure Licensing Siting Design Operation Termination of active institutional control Constructing off-site infrastructure Decommissioning Constructing on-site facilities Constructing disposal facility Active institutional control Passive institutional control Research & Development Environmental monitoring 29

30 Waste Disposal Options Surface Disposal Landfill Disposal Near-Surface Disposal 30

31 Waste Disposal Options (cont.) Geological Disposal 31

32 Classification Systems versus WAC Difference between waste acceptance criteria (WAC) and a waste classification system: Waste classification systems provide a national system of classification for managing all types of radioactive waste. Do not specify criteria for individual facilities. WAC are specific to a particular facility. WAC provide detailed specifications for waste to meet before it can be accepted at a particular facility. Waste classification is not a substitute for a facility specific safety case! 32

33 Summary Waste classification permits appropriate decisions to be made at each step of lifecycle management of wastes provides a systematic foundation for waste segregation programmes Allows to set up efficient management system for operators provides essential input for national waste management policy and strategy 33

34 Summary (cont.) 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. notwithstanding the generic linkage between waste classes and disposal options, the suitability of waste for disposal in a particular disposal facility is required to be demonstrated by the safety case and supporting safety assessment for the facility 34

35 Radioactivity in NORM 35

36 Thank you for your kind attention! This activity is conducted by the IAEA, with funding by the European Union. The views expressed in this presentation do not necessarily reflect the views of the European Commission