PREDISPOSAL MANAGEMENT OPTIONS Daniela E. Alvarez, Ph. D PREDISPOSAL MANAGEMENT OPTIONS 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 Waste Tunis, 17-21, March 2014

PREDISPOSAL MANAGEMENT OF RW This Safety Requirements publication applies to the predisposal management of radioactive waste of all types and covers all the steps in its management from its generation up to its disposal, including its processing (pretreatment, treatment and conditioning), storage and transport. Such waste may arise from the commissioning, operation and decommissioning of nuclear facilities; the use of radionuclides in medicine, industry, agriculture, research and education; the processing of materials that contain naturally occurring radionuclides; and the remediation of contaminated areas

RADIOATIVE WASTE SOURCES Predisposal management of radioactive waste on all types

NUCLEAR FUEL CYCLE

PREDISPOSAL MANAGEMENT OF RW Basic steps: Processing Storage

STEPS IN THE PREDISPOSAL MANAGEMENT OF RADIOACTIVE WASTE The principal approaches to the predisposal management of radioactive waste are “delay and decay”, “concentrate and contain” and “dilute and disperse”

GENERATION OF RADIOACTIVE WASTE All radioactive waste shall be identified and controlled. Radioactive waste arising shall be kept to the minimum practicable Measures to control the generation of radioactive waste, in terms of both volume and radioactivity content, have to be considered before the construction of a facility, beginning with the design phase, and throughout the lifetime of the facility, in the selection of the materials used for its construction, and in the control of the materials and the selection of the processes, equipment and procedures used throughout its operation and decommissioning. The control measures are generally applied in the following order: reduce waste generation, reuse items as originally intended, recycle materials and, finally, consider disposal as waste

CHARACERIZATION AND CLASSIFCATION 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

CHARACERIZATION OF RW Radioactive waste has to be characterized in terms of its physical, mechanical, chemical, radiological and biological properties Radiological characterization: alpha, beta and gamma emitters It allows: Basic requirement to know the RW inventory Segregation of radioactive materials Decisions of proper treatment

PROCESSING OF RW The main purpose of processing radioactive waste is to enhance safety by producing a waste form, packaged or unpackaged, that fulfils the acceptance criteria for safe processing, transport, storage and disposal of the waste. Waste has to be rendered into a safe and passive form for storage or disposal as soon as possible. The processing of radioactive waste can yield effluent that is suitable for authorized discharge or material that is suitable for authorized use or clearance from regulatory control

PRE-TREATMENT The main objectives of pretreatment are to: • segregate waste into active and non-active streams in order to reduce the volume of radioactive waste to be processed; • separate an active stream into components or to convert the waste into a form so that it may be easily treated, conditioned, and packaged for storage and/or disposal Most used pretreatment processes are: Chemical adjustment of liquid waste: neutralize and prepare liquid waste for treatment and encapsulation in a matrix • destruct organics and corrosives that shorten package or equipment life Physical adjustment: decantation, filtration (remove organics and fine particulates) Decontamination Collection and segregation

acidic, basic, saline solutions PRE-TREATMENT SEGREGATION I SOLIDS DRY WET BIOLOGICAL COMPACTABLES NON COMPACTABLES BURNABLES NON Crud, spent ion resins INFECTIOUS PUTRESCIBLES Papers, gloves, plastic, rags Sharp materials, Tools, Debris Papers, gloves, plastic debris Animal Carcasses LIQUIDS AQUEOUS ORGANICS acidic, basic, saline solutions Solvents GASEOUS Filter systems

PRE-TREATMENT SEGREGATION II According to half life of radionuclides: Cleared waste < 100 days ; 32P (decay) > 100 days and < 30 years ; 90Sr - 60Co (interim storage) > 30 years , 63Ni (long term storage) According to activity: low, intermediate and high level

PRE-TREATMENT SEGREGATION III Collection at source in compatible containers : bottels, cans, bags, baskets, leaded cars, cabinets with shilding

TREATMENT Treatment includes operations intended to benefit safety and/or economy by changing the characteristics of the waste. Three basic treatment objectives are: • Volume reduction • Concentration of radionuclides into a small volume of the waste • Change of composition Most used treatment processes are: Chemical precipitation Ion exchange Evaporation Incineration Emulsification Size reduction (cutting) Transport of RW could be necessary to consider during treatment

TREATMENT The goal of waste treatment is to enhance safety At short-term, by making immediate improvements in the characteristics of the waste, At long-term, as one of a series of steps contributing to the safe predisposal management of RW DECAY PURIFICATION INTERIM STORAGE SEPARATION (evaporation, precipitation, filters, resins beds) Discharges or clearance Effluent discharged to environment Concentrated RW: (later: compaction / inmovilization) RW with radionuclides with short half-life (min-days) long half-life Treatment can be divided in two basic systems. DECAY: applies to RN with short half-lives (I131, etc..) and the remaining activity conforms to the authorized discharge limits or levels of exemption or clearance. Usually waste is stored until decay. PURIFICATION system: it is based on the reduction of the activity present in liquid streams or by removing gaseous pollutants. They are used when it is not possible to apply the systems decay due to the magnitude of the activity is too high or the volume too big. For removing RN it is used filters, evaporation of liquids, resins, etc. After treatment of RW, conditioning stage is coming.

TREATMENT (cont.) To select a treatment option, some considerations should be taken: During incineration of RW, releases of radionuclides to the environment can be produced During compaction, it is possible to produce release of volatile radionuclides and other airborne radioactive contaminants; or release of contaminated liquid; or chemical reactions of the material and even potencial fire and explosion hazards due to pyrophoric or explosive materials or pressurized components For non-combustible and non-compressible solid waste, for which delay and decay or decontamination is not a viable option, direct conditioning without prior treatment should be considered For treatment of aqueous waste, limitations due to corrosion, scaling, foaming and the risk of fire or explosion in the presence of organic material should be carefully considered

CONDITIONING Conditioning of radioactive waste includes: Immobilization Packaging The purpose of conditioning is to produce a packaged solid waste form compatible with storage, transport and disposal option Safety should benefit from the use of a matrix material, and the matrix material should be compatible with the packaging, handling and disposal Waste packages perform such that radionuclides are confined under both normal and accident conditions in handling, storage, transport and disposal

STORAGE Storage is by definition an interim measure, but it can last for several decades. The intention in storing waste is that the waste can be retrieved for clearance, processing and/or disposal at a later time Storage can occur in many forms and any stage of predisposal (e.g., raw, treated, conditioned)

STORAGE According to the quantities, physical, chemical and radiological properties of the RW as well as period of storage defined and degradability of the containers, the storage should ensure: Containment Shielding Retrievability Security Aplication of procedures Mechanical filters storage Container sheilding with lead

STORAGE Sufficient storage capacity should be provided for waste generated in normal operations with a reserve capacity for waste generated in any incidents or abnormal events. Extension of this capacity may be necessary in the event that the waste cannot be transferred off the site because, for example, a disposal facility is not available Radiation monitoring and visual inspection should be performed whenever the waste is handled or moved (placed into storage, retrieved or transported off the site). This serves to protect workers handling the waste, helps to prevent the accidental spread of contamination and provides an additional check of the record keeping system Emergency preparedness and response arrangements commensurate with the threat category of the facility A decommissioning plan should be prepared at the design stage of the facility

SMALL STORAGE FACILITIES FOR RADIOACTIVE WASTE Small inventories of radioactive waste comprising radionuclides with relatively short half-lives are typically handled at small waste storage facilities. Simple waste treatment activities such as low force compaction may also be carried out at them. In addition, sealed sources of various types may be handled at small waste storage facilities. Some types of radioactive waste may be stored for periods specifically to allow the radioactivity of the waste to decay to levels that permit its authorized discharge or removal from regulatory control (i.e. clearance). The stored radioactive waste should be characterized (e.g. by radionuclide type, inventory, activity concentration, half-life and the physical, chemical and pathogenic properties of the waste) and the results should be documented in an inventory log. If pathogenic radioactive waste is to be stored, it should be deactivated before its placement in storage Centralized facility can be a good option

STORAGE GENERAL OPERATIONAL CONSIDERATIONS The operational activities may include: receipt, storage and retrieval of waste; labelling of waste packages; inventory control; package inspection; radiation protection; monitoring and surveillance; record keeping; and preparation of waste packages for dispatch to another facility The procedures should be such as to ensure compliance with the operational limits and conditions approved by the regulatory body

WASTE ACCEPTANCE CRITERIA (WAC) Waste packages and unpackaged waste accepted for processing, storage and/or disposal shall conform to criteria consistent with the approved safety case Waste acceptance criteria should be developed for the storage facility, taking account all relevant operational limits and future requirements for disposal, if the latter are known The characterization data should include all necessary information concerning the radionuclide inventory and the physical, chemical and pathogenic properties of the waste. Relevant documentation should accompany the waste each time it is shipped Packages containing radioactive waste intended for transport shall comply with limits established in the IAEA Transport Regulations

RECORD KEEPING AND REPORTING TRANSPORT RW adequately packaged and contained can be transported by road, rail, air or sea in accordance with the national and international legal requirements RECORD KEEPING AND REPORTING The operator of a storage facility should establish a procedure for maintaining adequate documentation and records in accordance with the quality assurance programme The operator of the facility should periodically submit reports on compliance with the conditions of authorization to the regulatory body, in accordance with the required schedule Safety case and supporting safety assessment (prepared for operator) …………………

Thank you