1. 1 DECOMMISSIONING TECHNOLOGIES “SAFE DECOMMISSIONING OF NUCLEAR POWER PLANTS” Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” MODULE “WASTE AND SPENT NUCLEAR FUEL MANAGEMENT”

2. 2 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Contents 1. Waste management during decommissioning – purposes, time schedules, activities, techniques 2. Methods for RAW treatment and conditioning 3. RAW disposal 4. SNF management

3. 3 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Key terms and definitions Radioactive wastes (RAW) Radioactive material gas, liquid or solid form, which is not to be used any further, and which is controlled by the regulating authority in its quality of radioactive waste pursuant to the adopted national legislation. All activities, inclusive those activities associated with decommissioning connected with manipulation, preliminary processing, conditioning, storing or disposal of the radioactive wastes, except for transportation outside the site. This can also include all emissions. Management of radioactive wastes

4. 4 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Waste management during decommissioning Training objectives The trainees should be able to: –Explain the purposes of waste management during decommissioning of nuclear facility. –Define the RAW/non-radioactive waste management activities. –List the technical means and technological methods for treatment of RAW/non-radioactive waste.

5. 5 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Objectives of radioactive wastes management The objectives of the radioactive wastes management include all treatment of these using methods or technical tools ensuring:  both protection of personnel and people’s health, and of environment, now and in the future;  reduction of the burden that will be inherited by the generations to come within sensible limits.

6. 6 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Basic approaches with radioactive wastes management For the purposes of radioactive wastes management, 3 main approaches are applied either alone or combined:  delay and decay;  concentrate and contain;  dilute and disperse.

7. 7 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Basic approaches with radioactive wastes management The activities associated with radioactive wastes management are planned, implemented and controlled meeting 9 fundamental principles:  Human health protection  Environment protection  Ensuring safety beyond the limits of the national boundaries  Protection of the generations to come  Burden on the generations to come  National legal structure  Control over formation of radioactive wastes  Interrelation between formation of radioactive wastes and management thereof  Safety of installations for treatment of radioactive wastes

8. 8 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Time structure  Preparation and ensuring the following: –equipment for the entire radioactive wastes/non- radioactive wastes processing complex; –sites and premises for respective waste.  Initiation of processing: –radioactive wastes – with the initiation of works on preliminary decontamination, with formation of first liquid and solid radioactive wastes. –non- radioactive wastes – only after accumulation of needed amount of each of the types of waste.

9. 9 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Categorisation of radioactive wastes Solid radioactive wastes are classified into three categories:  category 1 - transitional radioactive wastes, which can be exempted of control after a certain period of time has passed;  category 2 – low and medium-active wastes;  category 3 – highly active wastes.

10. 10 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” General safety requirements with radioactive wastes management Applying radioactive wastes management, measures are taken to guarantee that at all stages of radioactive wastes management, each person, the society, and the environment are adequately protected against radiological or any other risks.

11. 11 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Planning radioactive wastes management Radioactive wastes management follows adopted and controlled:  Programme for radioactive wastes management  Programme for ensuring quality  Emergency plan

12. 12 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Radioactive waste management activities Radioactive wastes management includes the following main activities:  Preliminary treatment of radioactive wastes  Treatment of radioactive wastes  Conditioning of radioactive wastes  Disposal of radioactive wastes

13. 13 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Radioactive waste management activities Wastes and materials Preliminary processing Processing Conditioning Disposal Radioactive materials Control exempted materials

14. 14 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Preliminary treatment of radioactive wastes Objective  Reduction of amounts of the radioactive wastes due to be processed and conditioned  Correction of the characteristics of radioactive wastes aimed at facilitating processing, conditioning and disposal thereof Preliminary treatment of radioactive wastes may include main operations like: Preliminary treatment of radioactive wastes may include main operations like:  Identifying characteristics  Collection  Separation  Regulation of chemical composition  Decontamination

15. 15 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Treatment of radioactive wastes Objective Processing streamlines ensuring safety and/or reduction of expenses associated with wastes management applying modification of radioactive wastes characteristics. Treatment of radioactive wastes includes, when necessary, operations associated with: reducing the volume; removal of radionuclides from waste; modification of composition.

16. 16 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Conditioning of radioactive wastes Objective The objective of conditioning is producing solid form packed wastes corresponding to the disposal option selected and satisfying the requirements relevant to safe manipulation, transportation, storage and/or disposal. Conditioning of radioactive wastes includes operations associated with: Immobilisation of radioactive wastes Packing of radioactive wastes

17. 17 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Immobilisation of radioactive wastes Definition Immobilisation means having wastes shaped into a certain fixed shape by means of hardening and immobilising thereof inserting them into an appropriate matrix or leak-tight jacket.Objective Fixing (immobilisation) aims at reducing the likeliness of migration or dispersion of radionuclides in conditions of handling, transportation, storage or disposal of radioactive wastes.

18. 18 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Immobilisation of radioactive wastes  Fixing by using organic matrices  including in polymers  bituminization  Fixing by using inorganic matrices  cementation  vitrification  Special methods

19. 19 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Disposal of radioactive wastes Objective Disposal is the last stage of radioactive wastes management and aims at their positioning into facilities for continued storage with no intention in terms of withdrawing, long-term monitoring or technical servicing thereof. Using a system of both natural and artificial barriers, reliable insulation is achieved, which guarantees that leaking of radionuclides into environment will occur at acceptably low levels in all possible climatic, geologic, external or technology related impacts through a long period of time.

20. 20 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Technical means and technological methods, used for RAW treatment and conditioning When liquid wastes are processed, the following methods are applied:  Precipitation  Filtering  Sorption  Ion-exchange  Evaporation

21. 21 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Technical means and technological methods, used for RAW treatment and conditioning Technical means and technological methods, used for RAW treatment and conditioning When liquid wastes are processed, some other methods methods are also applied like :  Reagent coagulation  Electric coagulation  Micro-filtering  Ultra-filtering  Reverse osmosis  Electrodialisis

22. 22 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Technical means and technological methods, used for RAW treatment and conditioning When solid wastes are processed, the following methods are applied:  Burning  Moulding  Smelting

23. 23 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Technical means and technological methods, used for RAW treatment and conditioning Technical means and technological methods, used for RAW treatment and conditioning When radioactive wastes are prepared (conditioned), the following methods are mainly used:  Bituminisation  Inclusion into polymers  Case-hardening  Vitrification

24. 24 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Technical means and technological methods for treatment of non-radioactive waste When non- radioactive wastes are processed, the following methods are most commonly used:  Burning (combustible both solid and liquid wastes)  Crushing (building wastes)  Grinding (building wastes)  Smelting (both ferrous and non-ferrous metals)  Storage in waste deposits

25. 25 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Selection of technological methods and tools with radioactive wastes management Selection of technological methods and tools with radioactive wastes management Aspects influencing selection of individual technologies  Universality of technology (i.e. possibility of using thereof for other types of waste as well)  Resulting secondary waste  Features of resulting (final) product  Achievable volume reduction factor  Relation with existing technologies (for newly set up system of work with radioactive wastes)  Possibility of using thereof within needed term  Personnel and environment safety  Overall expenses (operational here included) and their break-up in time.

26. 26 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Methods for RAW treatment and conditioning Training objectives The trainees should be able to:  Explain technical means and methods application to RAW treatment and conditioning.  Define the separate contaminated waste treatment and conditioning methods.  Explain the RAW treatment and conditioning methods.  Determine the separate waste treatment and conditioning methods application areas.

27. 27 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Evaporation Description Description Treatment of liquid radioactive wastes using evaporation in distillers. Application field Application field Evaporation is a widely used method for reduction of volume of liquid low-, medium-, and high activity radioactive wastes.

28. 28 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Evaporation Diagram of rotor evaporator 1-motor-reducer, 2-separator, 3-rotor, 5-скрeбка, 6-mixer, 7-screw, 8-bearing, 9-bioprotection, 10-reducer, 11-electric motor, 12-хидрозaтвор, 13-рaзпрeдeлитeл, 14- капкоотделител,15-хидрозaтвор, 16-bioprotection A-heating steam, B-liquid waste, C-bitumen, D-heating steam, E- secondary steam, F-heating steam condensate, G-compound, H-condensate

29. 29 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Bituminisation of liquid radioactive wastes Description Bituminisation is a process, which consists in mixing processed concentrates with bitumen heated up to 120- 200 0 С. It allows inclusion of up to 40-50% radioactive dry residue. Application field Bituminising may be used to fix both homogeneous (cube residues, hydroxide slams, etc.) and heterogeneous (pulp, ion-exchange resins, perlite, etc.) wastes of either medium or low activity.

30. 30 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Bituminisation of liquid radioactive wastes Advantages  low solubility in water  high resistance to water diffusion  high chemical inertness  good biological inertness  high plasticity degree  good resistance to radiation impacts  high fixing speed  availability of the material itself and its affordable price

31. 31 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Bituminisation of liquid radioactive wastes Disadvantages  viscosity drops when temperature increases  combustibility (although it is hard to ignite)  ability of chemical interaction with some chemical compounds (nitrates)  low heat conductivity rate  tends to arch

32. 32 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Cementation Description Description Cementation of radioactive wastes is a method for fixing (achieving shape stability) of both solid and liquid radioactive wastes in a cement case. Application field Application field Widely applicable with hardening of both solid and liquid low-, medium-, and high activity radioactive wastes.

33. 33 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Cementation Advantages Advantages  low cost  relatively simple technology  high chemical inertness  high rigidness level  incombustibility  sufficient level of washability of a number of key radionuclides  the high thickness of the product is a prerequisite for good self-shielding  good resistance to radiation impact  availability of the material itself and its affordable price

34. 34 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Cementation Disadvantages  ability of chemical interaction with some chemical compounds (citric acid)  need of changing concentrate’s pH  changes both in volume and heat conductivity in the process of hardening of the mixture

35. 35 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Cementation Continuous cementing Installation A-additives B-pump C-water, D-concentrate E-resins F-proportioner G-mixer H-additives I-cement K- supplying device

36. 36 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Thermoplastic and reactive plastics Description Description Inclusion into polymers consists in mixing dry radioactive wastes that are being processed with polymers (e.g. polyethylene, polyester, vinyl ester) heated to above the plasticisation temperature with polymers in appropriate facilities (e.g. extruders) and their successive cooling in cases or packs. Application field Application field Used as an alternative to fixing using cementation.

37. 37 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Combustion (reducing to ashes) Description Description The method consists in burning combustible contaminated materials in appropriate premises, collecting the solid residue and filtering of exhausted gases. Application field Application field This method is applicable in treatment of solid combustible radioactive wastes such as polymers, organic ionites, textiles, paper, etc., and organic liquids (contaminated oils), contaminated to some extent (starting from low degree of contamination and through to highly contaminated).

38. 38 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Combustion (reducing to ashes) RAW combustion installation drawing A-fuel, B-solid waste, C-air, D-furnace, E-high temperature filter, F-heatexchanger, G-heater, H-scrubber, I-condenser, J-heater, K-adsorber, L-filter, M- stack

39. 39 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Press compacting of dry solid RAW Description Compacting is an operation of mechanical reduction of volume Application field Compacting is applied to wastes that are stable biologically, glass wadding, materials applied in electric engineering, etc.

40. 40 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” High-temperature technologies High-temperature technologies of processing and conditioning of radioactive wastes may refer to: High-temperature technologies of processing and conditioning of radioactive wastes may refer to:  Treatment of radioactive wastes by means of adding ceramic admixtures  РЕМ radioactive wastes processing technology

41. 41 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Treatment of radioactive wastes by means of adding ceramic admixtures Description Description Treatment of radioactive wastes by means of adding ceramic admixtures is a process of mixing, tableting, and successive baking of ceramic mass and radioactive wastes of an appropriate granulometric composition. Application field Application field Treatment of radioactive wastes by means of adding ceramic admixtures is used for treatment of powder-like materials of medium and low activity such as contaminated soils, etc.

42. 42 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” РЕМ technology Description Description This method is based on combining the process of burning of different materials to ashes on the surface of the melted glass mass and the introduction of solid non-organic products resulting from burning to ashes into glass alloy heated by plasma. Application field Application field Used in treatment of precipitates, saturated non-organic and organic sorbents, oils, organic compounds, contaminated soils, filters, glass, concrete, artificial material, rubber, wood, paper, etc.

43. 43 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” High level radioactive waste treatment methods Methods for treatment of high-activity radioactive wastes may include the following:  Vitrification  Plasma melting  Cold crucible technology

44. 44 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Vitrification Description Vitrification of radioactive wastes is a method for fixing (achieving shape stability) of solid radioactive wastes in a glass case. Application field Vitrification is mainly used for fixing of dry high activity radioactive wastes such as concentrates and saturated ionites.

45. 45 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Vitrification Vitrification of RAW through electroheating 1-ceramic body 2-gas lead 3-waste supply 4-melt lead 5-ceramic body 6-heat insulation 7-melt 8-separator 9-electrodes

46. 46 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Plasma melting Description Description Melting of radioactive wastes in a shaft-type furnace with a fuel-plasma accelerator of the burning process. Application field Application field Used for treatment of high activity radioactive wastes.

47. 47 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Cold crucible technology Description Description This technology consists in obtaining melt of processed radioactive wastes in a cooled induction-heated crucible. Application field Application field Cold crucible is mainly used for treatment of high activity radioactive wastes or in specific wastes such as radioactive precipitates with high contents of alfa-nuclides, saturated sorbents, dichromate, etc.

48. 48 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Metal RAW treatment and reprocessing Metal radioactive wastes are treated as follows:  Smelting of metal radioactive wastes  Compacting under high pressure  Disposal into environment after a preceding decontamination has been completed

49. 49 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Smelting of metal radioactive wastes Description Smelting of metal radioactive wastes in metallurgy facilities, most commonly in induction furnaces. Application field Smelting of metal radioactive wastes is used for the following objectives:  Treatment of low activity metal materials aiming their disposal into environment;  Reducing the volume of radioactive metal wastes and their processing into a form appropriate for permanent storage.

50. 50 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Contaminated soil activities Treatment of contaminated soils may include the following: Treatment of contaminated soils may include the following:  Treatment of radioactive wastes by means of adding ceramic admixtures  Vitrification of contaminated soils in situ  Vitrification of contaminated soils ex situ  Storage at sites for contaminated soils

51. 51 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Contaminated soil activities Vitrification in situ

52. 52 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Contaminated soil activities Disposal of sites for contaminated soil

53. 53 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Juxtaposition of methods for fixing of radioactive wastes FeatureCementPolymerBitumen Technology application range highmediumhigh Volume reduction factor negativepositive Cost lowhigh Productivity mediumhigh Compressive strength highmediumlow Fire resistance highmediumlow Degradation resistance high medium Radiation stability highmedium Ability to retain short-life radionuclides lowhigh Ability to retain actinoides highlow

54. 54 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” RAW disposal Training objectives The trainees should be able to: - Explain the final waste reprocessing. - Describe the requirements and the safety measures during RAW transport. - Describe the final disposal facilities and methods applied.

55. 55 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Final waste reprocessing Final processing of radioactive wastes includes:  Packing of conditioned radioactive wastes in individual packs  Packing of conditioned radioactive wastes in containers

56. 56 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Final waste reprocessing Stiffing of reprocessed and reconditioned RAW

57. 57 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Packing for final neutralisation of wastes using disposal Definition Definition Packing is deemed to be a packing set inclusive its radioactive contents presented by the consignment forwarder for shipment. The type of packing is determined in accordance with individual restrictions concerning the radioactive compounds shipped therein and with satisfying certain requirements to its construction.

58. 58 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Packing for final neutralisation of wastes using disposal Transportation and disposal of radioactive substances is performed using the following types of packing: 1. Industrial packing type 1; 2. Industrial packing type 2; 3. Industrial packing type 3; 4. Packing type А; 5. Packing type B(U); 6. Packing type B(M); 7. Packing type C

59. 59 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Transport to disposal location Definition Transportation means shifting the location of a certain consignment from its place of origin to its place of destination. The “transportation” activity includes all activities involved in preparation of the consignment for shipping, the activities associated with loading, transportation, unloading and reception thereof, inclusive transit outage and temporary storage of consignment if indispensable.

60. 60 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Transport to disposal location Transport to disposal location Ensuring safety is achievable if the following are met: 1. Adherence and control on requirements to: activity of radionuclides activity of packs transport index and criticality safety index labelling, marking and signs in transportation of radioactive compounds construction of packing sets and packs means of transport 2. Working out, endorsement, implementation and control of the following: radiation security programme programme for ensuring quality emergency plan

61. 61 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Transport to disposal location Type А packages

62. 62 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Marking of Packages Package marking is put on two opposite sides and lists following data:  RAW type  activity of package  Transport index or safety index per package criticality  Number per UN classification

63. 63 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Methods for final neutralisation of radioactive wastes using disposal Definition Definition  Disposal means depositing spent fuel or radioactive wastes in an appropriate facility with no intention of its successive extraction. Final neutralisation of radioactive wastes using disposal is carried out in:  underground depositories;  surface depositories.

64. 64 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Artificial and natural barriers Reliable isolation of depositories from environment is carried out by means of: 1. Artificial (engineering) barriers including – form of waste (fixed in stable shape case) – container – reinforced concrete construction of depository – multi-layer covering – clay bath around constructive assemblies – drainage system 2. Natural barriers (geologic formations)

65. 65 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” SNF management Training objectives The trainees should be able to: - Determine and describe the structure of the nuclear fuel cycles. - Define and describe the SNF storage technologies (“Dry” and “Wet” SNF storage).

66. 66 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Nuclear fuel cycle Definition All operations associated with nuclear power production, inclusive mining ore processing, uranium or thorium processing and dressing, production of nuclear fuel, operation of nuclear reactors, processing of nuclear fuel, decommissioning, and any activity referring management and disposal of radioactive wastes.

67. 67 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Types of nuclear fuel cycles The three basic types of nuclear-fuel cycles are identified depending on whether the spent fuel undergoes processing: The three basic types of nuclear-fuel cycles are identified depending on whether the spent fuel undergoes processing:  closed nuclear-fuel cycle – processing (regeneration of spent nuclear fuel);  open nuclear-fuel cycle – spent nuclear fuel does not undergo processing and fissionable materials are not returned into the nuclear-fuel cycle;  combination of both an open and a closed nuclear-fuel cycle.

68. 68 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Nuclear power plant Interim/temporary storage of spent nuclear fuel (30 – 40 years?) Interim storage of spent nuclear fuel in nuclear power plants (up to 10 years) Depository – disposal of radioactive wastes Controlled storing of solid and hardened radioactive wastes Processing of radioactive wastes Production of fuel Extraction and treatment of uranium Closed nuclear fuel cycle A basic pattern of a closed nuclear-fuel cycle

69. 69 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Open nuclear fuel cycle A basic pattern of an open nuclear-fuel cycle Nuclear power plant Interim storage of spent nuclear fuel Additional site for temporary storage of spent nuclear fuel Depository – disposal of spent nuclear fuel Production of fuel Extraction and treatment of uranium Up to 100 years

70. 70 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Basic structure of a nuclear fuel cycle A nuclear fuel cycle includes the following stages and relevant activities: Initial stage of a nuclear-fuel cycle Includes operations and activities associated with obtaining nuclear fuel. Intermediate stage of a nuclear-fuel cycle Includes operations and activities associated with using nuclear fuel. Final stage of a nuclear-fuel cycle Includes operations and activities associated with processing, storing and disposal of spent nuclear fuel.

71. 71 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Interim storing of spent nuclear fuel Definition Interim storing is an operation associated with depositing of spent nuclear fuel in extra-reactor nuclear operations for storing prior to its successive treatment (delayed treatment) and/or disposal. The following are used for the purposes of interim storing: - depositories for spent nuclear fuel with wet storing; - depositories for spent nuclear fuel with dry storing.

72. 72 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Wet storing of spent nuclear fuel Description Wet storing consists in depositing of spent nuclear fuel in depositories where the spent fuel is stored in a poll filled with a liquid (most commonly water). The water along with the construction of the pools ensures: - reliable heat abstraction from the residual heat release of the spent nuclear fuel; - protection against radiation; - guaranteeing subcriticality with normal operation and likely external effects.

73. 73 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Dry storing of spent nuclear fuel Description Description Dry storing consists in depositing of spent nuclear fuel in depositories where the spent fuel is stored in gas environment, for example air or inert gases. Dry depositories include facilities for storing spent fuel in containers, bunkers or chambers.

74. 74 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Diagram of a container for dry storage of spent nuclear fuel

75. 75 Project BG/04/B/F/PP-166005, Program “Leonardo da Vinci” Cycle of operation typical of dry storage of spent nuclear fuel