1. Role and Development of the Safety Case Components of the Safety Case

2. Learning Objectives Role of the safety case. Development of the safety case. Components of the safety case. Interacting process. Summary 2

3. Learning Objectives Role of the safety case. Development of the safety case. Components of the safety case. Interacting process. Summary 3

4. 4 Introduction In the Module SCD 2 we studied the safety requirements for the safety assessment and safety case. In this module we will go through the components and specific issues of the safety case. The safety case is the basis for all safety considerations in respect of siting and locating facilities, construction, operation, decommissioning and/or closure of the facility, including the justification for changes The basis for interaction and dialogue between the operating organization and the regulatory body 44

5. Origin of the phrase “safety case”? OECD-NEA 1999 Has sections on “The Incremental Development of a Repository and its Safety Case” and “The Development of a Safety Case” 5

6. Definitions (OECD-NEA 1999) Safety assessment Safety assessment is the evaluation of long-term performance, of compliance with acceptance guidelines and of confidence in the safety indicated by the assessment results. Safety case A safety case is a collection of arguments, at a given stage of repository development, in support of the long-term safety of the repository. A safety case comprises the findings of a safety assessment and a statement of confidence in these findings. It should acknowledge the existence of any unresolved issues and provide guidance for work to resolve these issues in future development stages. 6

7. IAEA definition Safety Case “A collection of arguments and evidence to demonstrate the safety of a facility or activity. This will normally include the findings of a safety assessment and a statement of confidence in these findings. For a repository, the safety case may relate to a given stage of development. In such cases, the safety case should acknowledge the existence of any unresolved issues and should provide guidance for work to resolve these issues in future development stages”. 7

8. Overview of the Safety Case The operator shall prepare a safety case and a supporting safety assessment. In the event of a step by step development or in the event of the modification of the facility or activity, the SC and its supporting SA shall be reviewed and updated as necessary. Regulatory body is responsible to derive and document in a clear and unambiguous manner the criteria on which the regulatory decision making process is based. 8

9. Purpose of safety case Demonstrate that all planned activities can be carried out in a safe manner. Provide guidance for the design, engineering and planning of operations to ensure safety. Input to regulatory process, including evidence of compliance and arguments for confidence building. Some countries do not use the term SC in a formal way, but the approaches and processes to demonstrate safety are similar. 9

10. Scope of the safety case Relevant facilities / activities:  Processing of radioactive waste  Clearance and Discharges  Storage facilities  Transport  Disposal  Intervention situations (e.g. old storage facilities) All types of wastes  low level to high level waste  disused sealed sources  NORM 10

11. Components of the Safety Case The components of safety comprise the following elements: the context, the safety strategy; the facility description, safety assessment, limits, controls and conditions, iteration and design optimization, uncertainty management and integration of safety arguments. 11

12. Role of the safety case Demonstrating operational safety and providing reasonable assurance that the facilities will perform in a manner that protects human health and the environment, and fulfil relevant criteria. Aiding decision making on the licensing of the facilities. Identifying uncertainties in the performance of the facilities, describing the possible significance of the uncertainties, and identifying approaches for the management of significant uncertainties. Compatibility with a disposal option should be demonstrated, in the event that a disposal option has not been identified at that stage, assumptions should be made about the likely options and clearly set down. 12

13. Role of the safety case Integrating relevant scientific (and other) information in a structured, traceable and transparent way. Demonstrating that consideration has been given to the subsequent steps of management and their compatibility. Developing and demonstrating an understanding of the potential behavior and performance of the facilities. Both short medium and long term aspects should be considered and the possible need for future handling and treatment of the waste and the risks and doses that may be associated with these activities. Facilitating communication amongst stakeholders on issues relating to the facilities. 13

14. Learning Objectives Role of the safety case. Development of the safety case. Components of the safety case. Interacting process. Summary 14

15. Development of a Safety Case Development of the safety case should commence at the inception of the project and should be continued through all steps in the development and operation of the facility, through to its decommissioning or closure. Development of a SC should proceed within an iterative process that evolves with the development of the facilities. The formality and level of technical detail of the SC depend on the stage of development of the project, the required decisions and specific national requirements. SC arguments should be updated (e.g. national requirements, or other factors that are relevant to the decision making process). 15

16. Development of a Safety Case When developing the safety case, the needs of the key parties that will review, use and approve the safety case (e.g. government, the regulatory body and interested parties) should be identified and should be well understood; such needs will depend on the local and national situation. The early development and adoption of a strategy for safety is a key point in the development of the safety case. The safety case and supporting safety assessment are to be reviewed and updated periodically as necessary to reflect actual experience and increasing knowledge and understanding, with account taken of any relevant operational experience feedback or other aspects that are relevant for safety. 16

17. Development of safety case The safety case concept is of particular importance and benefit for large predisposal waste management facilities; For smaller scale facilities the elements of the safety case process are still relevant, however The level of complexity and detail should be commensurate with the potential hazard; Some aspects will be proportionally less demanding or less relevant (e.g. development in stages). 17

18. Development of a Safety Case During facility lifecycle, the safety case will evolve in the fallowing main stages: Concept development; Siting and site investigation; Design; Construction and commissioning; Operation and modifications; Shutdown and decommissioning; Closure and post closure (for disposal) 18

19. Safety case development CONCEPT & SITING SITE SPECIFIC DESIGN CONSTRUCTION OPERATION Decommissioning or Closure POST- CLOSURE SITE CHARACTERIZN CONCEPT DEVELOPMENT SAFETY CASE DEVELOPMENT FACILITY DEVELOPMENT 19

20. Concept and siting The first step in the pre-operational phase addresses concept and design development; At this stage it will not be possible to provide a detailed description and assessment of the facility or activity; However, key aspects related to the safety strategy and to the description of the design concept have to be addressed; 20 Waste body Groundwater Meteoric water Contaminated water

21. Concept and siting The safety case for this step should present the safety strategy and the way it will be met: In the absence of any quantitative demonstration, qualitative justifications have to be provided; Safety case should address the design concept and explain how the characteristics and properties of each component of the system are intended to provide for the allocated safety functions and how this will evolve with time; 21

22. Concept and siting This should be supported by: An overview of the technical feasibility of the proposed design options, identifying aspects that rely on already proven techniques and those that are new and need future confirmation through experimental tests An overview of the level of knowledge on the ability of each component of the system to fulfil its expected role under anticipated conditions and accounting for the possibility of key perturbations that have already been identified An assessment how the components of the system will function together in a complementary manner to ensure that there is adequate defense in depth and that safety is not unduly dependant on a single safety function 22

23. Concept and siting Radiological impact assessments can only be very preliminary at the conceptualization step; Nevertheless, it is desirable to carry out such preliminary assessment: to provide a broad order of magnitude estimate of possible impacts, based on generic considerations of site performances; to begin to identify the features of the facility and environment that are likely to be important to safety. 23

24. Concept and siting For disposal facilities at the stage of site investigation and site selection, the safety case should support the process leading to the identification of one or more potential disposal sites and should assist in the progression to the next step of development The safety case and its content will evolve as the project develops in terms of engineering and in terms of characterization of the different natural and engineered components of the disposal system At this stage, the safety assessment is initially generic in nature, but will evolve as the design develops and the level of detail of the site characterization increases 24

25. Concept and siting At the stage of site investigation and selection, the basic site characteristics should be described in such a way that they show how the safety function of each natural and engineered component within the proposed design options will be achieved for the site(s) under consideration The development of scenarios and assessment modelling capabilities should be sufficiently advanced so as to allow estimates with reasonable confidence of at least the order of magnitude of impacts Justification should be provided for the main assumptions used and simplifications adopted 25

26. Concept and siting Siting should consider the affect the facility or activity will have on: Other activities on the site; On any neighboring populations. Consideration needs to be given to: Effects of other activities or facilities on the proposed facility or activity; Management, predisposal, discharges or clearance of any wastes generated. 26

27. Concept and siting The safety case should also contain information about the management systems: Organizational structure; Required resources to undertake the project; Programme for the project planning; Information management system. It is also necessary to develop and implement plans for regulatory and stakeholder dialogue. The output of the safety case at this stage of development is justification that the facility or activity should, in principle, be undertaken and that it appears safe to do so. 27

28. Concept and siting The output of the safety case at this stage of development is justification that the facility or activity should, in principle, be undertaken and that it appears safe to do so. 28

29. Safety case development CONCEPT & SITING SITE SPECIFIC DESIGN CONSTRUCTION OPERATION Decommissioning or Closure POST- CLOSURE SITE CHARACTERIZN CONCEPT DEVELOPMENT SAFETY CASE DEVELOPMENT FACILITY DEVELOPMENT 29

30. Design During the design development and construction, the safety case will be further developed to provide a mature assessment of the engineering and of the impact of the facility or activity; The safety case should demonstrate that: Likelihood of a component of the system failing is low, In the event of degradation, the loss of a safety function of one component does not jeopardize the safety of the whole system. 30

31. Design For a disposal facility, both operational safety and long term safety should be assessed. An appropriate monitoring and surveillance programme should be developed and implemented before excavation and/or construction and commissioning of the facility is commenced. The impact of any modifications to the design that have been implemented during the excavation and/or construction period should be considered in the safety case and associated safety assessment. 31

32. Design The design of any radioactive waste facility should consider that the facility eventually will be shutdown and decommissioned or closure. From the very earliest stage of the safety case development decommissioning must be addressed to justify its safety. The justification should be based upon techniques that are currently available and commensurate with the level of resources likely to be available at the time of closure. 32

33. Design The output of design stage of the safety case development is justification that the facility or activity, as designed, can be safely constructed and operated. 33

34. Safety case development CONCEPT & SITING SITE SPECIFIC DESIGN CONSTRUCTION OPERATION Decommissioning or Closure POST- CLOSURE SITE CHARACTERIZN CONCEPT DEVELOPMENT SAFETY CASE DEVELOPMENT FACILITY DEVELOPMENT 34

35. Construction and commissioning During commissioning, specific attention should be paid to the performance of structures, systems and components important to safety A safety commissioning schedule should be prepared, detailing: Test to be undertaken, Results expected to ensure, that all aspects of the facility important to safety are adequately tested. 35

36. Construction and commissioning It is possible that separate safety cases and safety commissioning schedules will be required for in-active and active commissioning: The aim of the in-active commissioning safety case is to justify that the as built facility is safe to operate; The aim of the active commissioning safety case is to justify the safety of the facility to accept radioactive material. 36

37. Construction and commissioning The safety case should update information about the management system with emphasis on: Organization and procedures that are in place to assure the quality of the work performed, Linkage of designs to the outcome of research and development activities and safety assessment work, Keeping of records on the basis for design or operational decisions, Design basis information including information on design modifications, The expertise available to carry out tests and operate the facility or activity. 37

38. Construction and commissioning The safety case at this stage should demonstrate that the as constructed facility meets the safety requirements specified in the final design. This should include the impact of any modifications to the design, which have been implemented during the construction stage. 38

39. Safety case development CONCEPT & SITING SITE SPECIFIC DESIGN CONSTRUCTION OPERATION Decommissioning or Closure POST- CLOSURE SITE CHARACTERIZN CONCEPT DEVELOPMENT SAFETY CASE DEVELOPMENT FACILITY DEVELOPMENT 39

40. Operation Any significant differences between the actual and predicted performance of the facility or activity should be identified and the reasons investigated. All discrepancies should be justified. Information acquired during commissioning should be used to verify the validity of the safety assessment conducted for the previous stages If there are safety implications, then a re-examination of the related structures, systems and components important to safety should be carried out. 40

41. Operation The safety case should update information about the management system with particular emphasis on: Organization and procedures that are in place to assure the safety of operations, Record keeping and tracking system covering data, information and the records of decision, That there is sufficient expertise to operate the facility or activity, Interdependencies. 41

42. Operation During the operational life of a facility there may be a need to modify some aspects Where the modifications have a potential impact on safety, an appropriate safety assessment should be conducted or the current assessment updated before implementation of modification to assure continuing compliance with established safety requirements. 42

43. Operation There may be time dependent processes and events both internal and external, which will eventually modify certain assumptions, parameters and boundary conditions; Processes and events may be gradual or may occur at unpredictable times; Operational safety case should be reviewed periodically in order to detect significant changes to the underlying assumptions, parameters and boundary conditions. If necessary, the safety case should be revised accordingly. 43

44. Operation Periodic review should be mandatory at periods determined by the regulatory body; Periodic safety reviews may also be required to justify: Life extension of the facility beyond its original design life, Changes in the ownership or management of a facility, Changes in regulations. 44

45. Safety case development CONCEPT & SITING SITE SPECIFIC DESIGN CONSTRUCTION OPERATION Decommissioning or Closure POST- CLOSURE SITE CHARACTERIZN CONCEPT DEVELOPMENT SAFETY CASE DEVELOPMENT FACILITY DEVELOPMENT 45 SAFETY CASE PERIODIC REVIEW

46. Operation The updating of the safety assessment should take account of operating experience including data relating to anticipated operational occurrences, accident conditions and accident precursors both from: Facility or activity itself, Other similar facilities or activities. Where a treatment facility is developed for all decommissioning waste then it should be recognized that the treatment facility will also generate decommissioning waste that will need some sort of treatment facility. 46

47. Operation The aim of the operational safety case is to justify that the facility can be operated safely 47

48. Safety case development CONCEPT & SITING SITE SPECIFIC DESIGN CONSTRUCTION OPERATION Decommissioning or Closure POST- CLOSURE SITE CHARACTERIZN CONCEPT DEVELOPMENT SAFETY CASE DEVELOPMENT FACILITY DEVELOPMENT 48 SAFETY CASE PERIODIC REVIEW

49. Shutdown and decommissioning The waste management facility will eventually be closed and decommissioned. From the very earliest stage of the development of the safety case, this must be addressed to justify decisions on its safety. The justification should be based upon techniques that are currently available and should take into account the level of resources that are likely to be available at the time of closure. 49

50. Closure The post-closure period begins after the facility is closed. After closure, a period of institutional control may contribute to the safety of certain disposal facilities (in particular, near surface disposal facilities). Institutional controls may be of an active or passive nature. Examples of active measures are the monitoring of radionuclide concentrations in environmental media or the monitoring of the performance and integrity of barriers, in particular in the case of near surface disposal facilities. Post-closure maintenance measures (e.g. the repair of covers for near surface disposal) also fall into this category. Other institutional controls may be of a passive nature. These could, for example, be ensuring that records on the disposal facility are kept and restrictions on land use are in place. 50

51. Learning Objectives Role of the safety case. Development of the safety case. Components of the safety case. Interacting process. Summary. 51

52. Components of safety case Safety Case ContextSafety Case Strategy System Description Integration of Safety Arguments Limits, Controls and Conditions Safety Assessment Iteration and Design Optimization Management of Uncertainty Stakeholder and regulatory involvement Application of management system 52

53. Components of safety case Safety Case ContextSafety Case Strategy System Description Integration of Safety Arguments Limits, Controls and Conditions Safety Assessment Iteration and Design Optimization Management of Uncertainty Stakeholder and regulatory involvement Application of management system 53

54. Safety case context Purpose Depends on facility development stage (testing of initial ideas for safety concepts, site or location selection, demonstration of safety, periodic re-assessment, application to modify the facility or activity etc.) Scope Entire/single facility/activity, boundaries, interfaces. Approach Safety objectives, principles, criteria and regulatory requirements, application of graded approach. 54

55. Safety case context It is important that the context for a particular stage (revision) of the safety case is clearly presented and is modified as necessary for subsequent stages (revisions); It should be clearly defined: the lifecycle stage of the facility being considered; how the safety case has changed from previous safety cases; how this safety case will support future revisions of the safety case. 55

56. Components of safety case Safety Case ContextSafety Case Strategy System Description Integration of Safety Arguments Limits, Controls and Conditions Safety Assessment Iteration and Design Optimization Management of Uncertainty Stakeholder and regulatory involvement Application of management system 56

57. Safety case strategy Defines the approach that is taken in site selection, facility location, facility design and operation: to comply with the safety objectives, principles and criteria; to comply with regulatory requirements; to ensure that good engineering practice has been adopted and that safety and protection are optimized. Should be established at the early stage of facility conceptualization. 57

58. Safety case strategy The safety strategy should address a number of elements: Concept for defense in depth; Concept for shielding and containment; Waste processing approaches.; Waste minimization; Waste management optimization with regard to reuse, recycling and clearing of materials; Interdependencies with other predisposal management steps and with disposal of the waste; Uncertainty management. 58

59. Safety case strategy As the project develops, the safety strategy should be continually validated and any changes should be justified in the safety case; It is also important that any evolution of the safety strategy be carefully recorded and the records preserved for use in the future when staff may have changed. 59

60. Components of safety case Safety Case ContextSafety Case Strategy System Description Integration of Safety Arguments Limits, Controls and Conditions Safety Assessment Iteration and Design Optimization Management of Uncertainty Stakeholder and regulatory involvement Application of management system 60

61. Description of facility and waste The description of the waste management facility or activity should provide the basis on which the safety assessment is carried out. The description should contain, depending on the type of facility, information on the: Site conditions; Facilities and activities; Waste. 61

62. Description of facility and waste Site conditions To be identified and described: Site conditions and the associated events, of both natural and man made origin, that could: influence safety and impose demands on the facility or activities and its equipment and components; The objective is to establish: the normal or average situation and to identify any more extreme but credible events to be considered. 62

63. Description of facility and waste Facilities and activities The facility design and the fundamental assumptions upon which the design is based should be addressed in depth in the safety case. Facility structures; Systems and components and their importance for safety; Range of conditions under which the facility may operate; Hazards to which the facility may be exposed; Interfaces; Operational aspects such as operating and maintenance procedures, controls and monitoring. Personnel competencies, safety measures, and the quality of training. 63

64. Description of facility and waste Waste For each type of radioactive waste to be processed or stored, as well as material that is cleared/ discharged at the facility or within the activity: Volume and form; Radionuclides of concern and the radioactive content; Presence of fissile materials; Other physical, chemical and pathogenic properties; Secondary waste streams that may arise from waste processing should be included. 64

65. Components of safety case Safety Case ContextSafety Case Strategy System Description Integration of Safety Arguments Limits, Controls and Conditions Safety Assessment Iteration and Design Optimization Management of Uncertainty Stakeholder and regulatory involvement Application of management system 65

66. Safety assessment Safety assessment needs to address and assess a number of features of facility or activity, such as: Radiological impacts Safety functions Site characteristics Radiation protection Engineering aspects Operational safety Long-term safety …another presentation to come 66

67. Components of safety case Safety Case ContextSafety Case Strategy System Description Integration of Safety Arguments Limits, Controls and Conditions Safety Assessment Iteration and Design Optimization Management of Uncertainty Stakeholder and regulatory involvement Application of management system 67

68. Limits, controls and conditions The safety case assists in the establishment of license conditions and other controls and requirements The safe operating specifications are used as an input to designing of operational programmes and procedures, including maintenance, inspection and testing requirements Limits and conditions of particular importance for a facility or activity are the acceptable waste inventory and/or the concentration levels for specific radionuclides in the waste Waste acceptance criteria for the facility may be established both for individual waste packages and for the facility as a whole 68

69. Components of safety case Safety Case ContextSafety Case Strategy System Description Integration of Safety Arguments Limits, Controls and Conditions Safety Assessment Iteration and Design Optimization Management of Uncertainty Stakeholder and regulatory involvement Application of management system 69

70. Integration of safety arguments The safety case should provide a synthesis of the available evidence, arguments and analyses: How relevant data and information have been considered, how models have been tested How a rational and systematic assessment procedure has been followed What are limitations of currently available evidence, arguments and analyses What are principal grounds on which a judgments respect to the planning and development of facility or activity have been made 70

71. Integration of safety arguments Safety case includes all the different lines of evidence, arguments and analyses that assess the quality and performance of facility at a given stage of planning and development A clear distinction needs to be made between objectives and criteria for safety and the indicators used to demonstrate that these criteria are met and the objectives are fulfilled Confidence in safety case at any stage will be enhanced if each safety case version will include a plan for further work as necessary to address remaining and unresolved issues 71

72. Components of safety case Safety Case ContextSafety Case Strategy System Description Integration of Safety Arguments Limits, Controls and Conditions Safety Assessment Iteration and Design Optimization Management of Uncertainty Stakeholder and regulatory involvement Application of management system 72

73. Iteration and design optimization The actual decision making process is multi-faceted in that several varied and sometimes competing factors have to be brought together and reconciled to reach a decision This process will be iterative in most practical cases Iterations will depend on the status of facility development, the required decisions as well as the availability of data their quality 73

74. Components of safety case Safety Case ContextSafety Case Strategy System Description Integration of Safety Arguments Limits, Controls and Conditions Safety Assessment Iteration and Design Optimization Management of Uncertainty Stakeholder and regulatory involvement Application of management system 74

75. Management of uncertainties Uncertainties may have implications on the outcome of the safety analysis and the decisions made. Treatment of uncertainties: Identify uncertainties in the performance of facility; Identify the possible significance of the uncertainties; Identify approaches for the management of significant uncertainties. 75

76. Components of safety case Safety Case ContextSafety Case Strategy System Description Integration of Safety Arguments Limits, Controls and Conditions Safety Assessment Iteration and Design Optimization Management of Uncertainty Stakeholder and regulatory involvement Application of management system 76

77. Involvement of interested parties Early involvement of interested parties should be part of the process of building confidence in the safety of the facility A range of different models for involvement of interested parties has been applied in different States A key consideration is that interested party involvement should take place within an open and transparent framework for consultation, with clearly defined rules of procedure 77

78. Independent review Independent peer review should play an important role in building confidence in the safety case Independent peer review should be an active and ongoing part of the work leading to development of the safety case, and should begin at an early stage in the project Peer reviews should be fully documented In certain circumstances, international peer review teams should be established to focus on one or more specific topics or to evaluate an entire safety case and/or supporting safety assessment. 78

79. Components of safety case Safety Case ContextSafety Case Strategy System Description Integration of Safety Arguments Limits, Controls and Conditions Safety Assessment Iteration and Design Optimization Management of Uncertainty Stakeholder and regulatory involvement Application of management system 79

80. Management system The regulatory body and the operator are required to put in place appropriate management systems to ensure the quality of all safety related work Development of the safety case and supporting safety assessment should be conducted within a management system that can ensure an adequate level of quality Traceability requires a clear and complete record of the decisions and assumptions made, and of the models, parameters and data used in arriving at a given set of results Transparency requires openness, communication and accountability 80

81. Learning Objectives Role of the safety case. Development of the safety case. Components of the safety case. Interacting process. Summary. 81

82. Summary This presentation covered the role and development of the Safety Case It aimed to help you understand: The role of the safety case. The stages in the development of the safety case. The main components of the safety case. The Interacting process. 82