Segment SCD 4.3 Module SCD 4: Safety Case Segment SCD 4.3 Documentation and use of the safety case.

Module SCD 4: Safety Case

Segment SCD 4.3 Segment SCD 4.3

Documentation and use of the safety case

Learning ObjectivesLearning Objectives

The objectives of this segment are to consider:

•How to compile and draw together all the different information comprising the safety case.

•How to use the safety case.

2

3

IntroductionIntroduction

In the previous presentations we studied the role of the safety case, the development of the safety case and components of the safety case and the Specific issues important for the development of the safety case.

The safety case is the basis for the safety considerations in respect of siting and locating facilities, construction, operation, decommissioning or closure of the facility, including the justification for changes

The basis for interaction and dialogue between the operating organization and the regulatory body

33


The objectives of this segment are to consider:

•How to compile and draw together the all of the different information comprising the safety case.


4

Documentation of the safety caseDocumentation of the safety case

• The safety case provides a basis for decision making and is presented to the relevant decision makers for their review and consideration.

• The confidence of the interested parties in the findings of the safety case should, however, be enhanced if the arguments and evidence are presented in a manner that is open and transparent, and all relevant results are fully disclosed and subject to quality control and independent review.

• The structure and the documentation process are influenced by the expectations of the intended audience.

• The documentation of the safety case should cover, at a minimum, the safety assessment and the operating limits and conditions.

5


The main elements should be clearly documented and presented, and should include:

•the executive summary;

•the introduction and context for the safety case (or safety assessment);

•the strategy for safety;

•the safety assessment;

•synthesis and conclusions;

•a plan for follow-up programmes and actions;

•traceability and transparency of the documentation;

6




•the introduction and context for the safety case;






7

Executive summaryExecutive summary

• At the highest level, the documentation of the safety case should contain an executive summary that briefly describes:

– the project,

– the main safety related issues associated with the project,

– the evidence, arguments and main assessment results,

– the proposed follow-up and options for mitigation that would address the safety issues identified, and

– any uncertainties and concerns of interested parties.

8

Executive summaryExecutive summary

• For most interested parties, the summary will provide the first and most lasting impression of the project. Consequently, this section should be clear, complete and concise.

• The use of summary tables, graphics and flow charts should be considered as these are effective ways to present information clearly and accurately.

• The use of complicated technical terminology should be avoided, to the extent possible.

• The executive summary can be presented under a separate cover and may be more widely distributed than the rest of the documentation. It may also be presented in different languages to meet the needs of local communities.

9










10

Introduction and context for the safety caseIntroduction and context for the safety case

In the introduction, the following main aspects should be outlined:

• A brief description of the project that provides its specific objectives, background, various stages involved and its current status;

• The policy and regulatory contexts under which the safety case has been prepared and presented;

• The roles and responsibilities of the various organizations involved in the decision making process, including the framework for public consultation and involvement;

11



•A clear guide to the decision making process;

•A comparison with other similar projects (national and international);

•A discussion of the status and maturity of development of the technologies that will be used;

•A statement on the need for and importance of the project, in order to support and justify the safety case;

•A discussion of alternatives that have been considered and reasons for the preferred alternative;

12



•The key decisions that have been and will have to be made during the course of the proposed project;

•A description of critical timing considerations associated with the project;

•An overview of how compliance with regulatory requirements will be ensured by the operator and how compliance will be verified by the regulatory body;

•An overview of the operator’s management system and its ability to address the challenges associated with the project adequately.

13










14

Strategy for safetyStrategy for safety

• Following the presentation of the purpose and context for the safety case, the documentation of the safety case should provide an overview of the high level approach that will be used to achieve safety.

• The objective of the section on strategy for safety is to demonstrate that the overall approach and methods adopted to design, assess, construct, operate, shut down and decommission the waste management facility or activity are adequate to ensure safety.

• The section should also include confidence building arguments that are relevant to the strategy for safety.

15

Safety Strategy


The main aspects to be considered include the following:•Strategy and approach to manage the different stages of development of the facility or activity (e.g. site evaluation, construction, operation, shutdown, decommissioning);

•How the adopted strategies apply good engineering principles and practices;

•Management and reduction of uncertainties;

•The basis for making decisions;

•Safety features embedded in the design of the facility and the levels of defence in depth used;

16


The main aspects to be considered include the following:

•The rationale for selecting the assessment methodology and the time frame and time windows for the assessment, including a discussion of the various assessment approaches and the tools used to verify, confirm and compare assessment findings;

•Peer reviews conducted and consistency with international guidance and practices;

•Other high level arguments as appropriate.

17










18

Safety assessmentSafety assessment

• The section on safety assessment should document the details of the safety assessment, which forms the scientific and technical basis for the safety case procedure.

• This is the section that will be scrutinized by technical reviewers and the regulatory body.

• Documenting the safety assessment involves a detailed description of the context for the safety assessment, each step of the assessment, the assessment findings and the conclusions.

• Confidence building arguments should be documented at each step of the safety assessment as well as for the overall safety assessment.

19

Safety assessmentSafety assessment

• All relevant data, assumptions, models and the results of the assessment should be fully documented.

• The level of confidence in the evaluation results or safety margin and future actions should be identified.

• The quantitative and qualitative outcomes of the safety assessment form the basis for the safety case.

• These should be supplemented by supporting evidence for and reasoning about the robustness and reliability of the safety assessment and its assumptions, including information on the performance of individual system components as appropriate.

20










21

Synthesis and conclusionsSynthesis and conclusions

This section on synthesis and conclusions should:• Draw together the key findings from the safety assessment;

• Highlight the main evidence, analysis and arguments that quantify and support the claim that the facility or activity is safe;

• Present an evaluation of uncertainties and unresolved issues and discuss planned steps to resolve them;

• Describe complementary evidence for safety, e.g. evidence for safety beyond the time frame for which quantitative assessment has been performed;

• Present statements of confidence that take account of additional evidence and arguments that complement the findings of the safety assessment.

22










23

Follow-up programmes and actionsFollow-up programmes and actions

• In particular when the safety case is developed in a step by step approach, it is important to put each revision of the safety case into the context of the overall development process.

• Necessary activities for the subsequent stage of development of the safety case should be described, such as acquisition of additional data or planned improvement in modelling.

• If certain activities can only proceed after decision points or milestones have been reached (e.g. decisions on the site of the facility or activity), these should be identified.

24










25

Traceability and transparency of the documentation Traceability and transparency of the documentation

• All documents produced in the context of the safety case, should convey a consistent message about safety issues. In other words, the message should remain the same and not be changed to suit the expectations of a particular audience.

• The main documentation of the safety case should provide sufficient information for the key safety arguments and the evidence supporting them to be clearly understandable.

• The documentation should show that the safety case is based on sound scientific evidence and arguments using established technical experience and analyses.

26


• The documentation should be clearly written and uncertainties and limitations as well as their implications for safety should be acknowledged.

• The documentation should be well structured, transparent and traceable.

• The documentation should be transparent such that the information is readily available to interested parties, by being clear and understandable and by clearly presenting the justification and rationale behind key assumptions.

27


• The documentation should be such that the procedures followed and the key decisions taken in the development of the facility or activity and of the safety case are traceable.

• This should include showing how follow-up actions and programmes are put forward at early stages to confirm assumptions made or how unresolved uncertainties have been addressed and/or will continue to be addressed.

• It should also be shown how key decisions have been documented and recorded by including a clear referencing system.

28


• The safety assessment methodology should be well structured, transparent and traceable.

• It should enable the regulatory body and other technical reviewers to follow the logic and understand the assumptions used in the assessment easily and, where desired, to reproduce the assessment results.

• The safety case should provide a full description of the practical methods used to identify and reduce uncertainties

• The documentation should identify the assumptions and uncertainties that impact the most on safety.

29


• The documentation of the safety case should be updated periodically in accordance with a systematic plan.

• The operator should implement proper controls over the process for approval of the documentation of the safety case and over updates to the set of data and parameter values, models, scenarios and computer codes on which the safety case is based and that are used in safety assessment.

• Documents should be subject to formal review processes.

30


• Traceability necessitates a clear and complete record of the decisions and assumptions made, and of the models, parameters and data used in arriving at the results.

• The record should include information on when and by whom various decisions and assumptions were made, how these decisions and assumptions were implemented, what versions of modelling tools were used, and what the ultimate sources of the data are, etc.

31


• Traceability necessitates the highest standards of quality assurance.

• Traceability necessitates a clear and complete record of the decisions and assumptions made, and of the models, parameters and data used in arriving at the results.

• Traceability further implies that the regulatory body or other technical reviewers should be able to reproduce part or all of the assessment results from the documentation of the safety assessment.

• Traceability will be greatly increased by presenting the safety case in a hierarchically structured set of documents.

32


At the end of this segment the learner will be able to know:

•How to compile and draw together the all of the different information comprising the safety case.


33

Uses of the safety caseUses of the safety case

• The safety case may be used for several purposes depending on the stage of the design, construction, operation, shutdown and decommissioning of the facility or activity.

• At an early stage, safety assessments should be used to compare and assess the feasibility of different options.

• Later, the safety case should be used to inform the licensing process and to provide for the establishment of suitable limits and conditions on operation.

• The safety case should, at all times, be consistent with the current stage in the lifetime of the facility.

34


The uses of the Safety Case compromises among others:•Comparison of options

•Prioritization of data acquisition and research and development

•Facility design and operation

•Licensing

•Construction and commissioning

•Operation

•Monitoring

•Management controls

35

Comparison of optionsComparison of options

The safety case may be used to provide a basis for the comparison of disposal options, for example:

•Comparison between different sites for new facilities and prioritization of site characterization, and related research and development;

•Comparison of different types, designs for the facility;

•Comparison of different risk management and remediation options for existing facilities;

•Comparison of different pretreatment options.

36





•Licensing


•Operation

•Monitoring


37

Prioritization of data acquisition and research Prioritization of data acquisition and research and developmentand development

• The safety case should integrate existing knowledge on a wide range of topics and should provide a means of judging their relative importance.

• Initially, the safety case may be based largely on generic data but, as the programme to develop the facility progresses, the safety case will include more site specific information.

• The safety case should be used to guide and prioritize the acquisition of data and research and development programmes so that they address important areas of uncertainty as identified in the safety case.

38





•Licensing


•Operation

•Monitoring


39

Facility design and operationFacility design and operation

• The safety case should be used to assist in the design and operation of the facility throughout its development.

• The construction and operation of the facility should, at all times, be consistent with the safety case, so that operational decisions do not cause unintentional effects on performance of the system.

• Operational decisions relevant to safety should be investigated and may require an update of the safety case prior to their implementation.

40





•Licensing


•Operation

•Monitoring


41

License

LicensingLicensing

• A principal function of the safety case is in the licence application and approval process.

• The regulatory body may require that the safety case be revised at various stages in the licensing process, including for approval to construct, operate and shut down the facility, and whenever there are significant changes in the facility or activity.

• The safety case should anyway be updated periodically to reflect new information acquired.

42

LicensingLicensing

• The licence for predisposal waste management facilities and activities located at other facilities, such as nuclear power plants, may be granted within the framework of the licensing procedure for the main facility.

43

License





•Licensing


•Operation

•Monitoring


44

Construction and commissioningConstruction and commissioning

• In conducting the safety assessment, a number of assumptions will be made in relation to the design, construction, commissioning, operation and decommissioning of the facility.

• It is important that these assumptions are realized in practice.

• The plant should be built according to the assessed design, and the structures, systems and components that are important to safety should undergo commissioning tests to demonstrate that they perform as expected.

45





•Licensing


•Operation

•Monitoring


46

OperationOperation

• The operating procedures for the facility should be drawn up to ensure that the facility will be operated in accordance with design specifications.

• Such procedures should be assessed for adequacy as part of the overall safety assessment and safety case process.

• A formal procedure for control of modifications should be established and maintained that will ensure that any proposed changes to the facility or its proposed operations remain within the assessed envelope.

• Additional assessment should be carried out to demonstrate the acceptability of a modification.

47





•Licensing


•Operation

•Monitoring


48

MonitoringMonitoring

• The safety case should be used when evaluating potential exposure pathways and in establishing and reviewing the environmental monitoring programme for the site and the surrounding area.

• Surveillance environmental monitoring programmes should be established to verify that the facility or activity is performing as expected and that each component is achieving its safety function.

49





•Licensing


•Operation

•Monitoring


50

Management controlsManagement controls

The safety case should demonstrate the necessary combination of management controls, covering, for example:

• quality assurance,

• maintenance,

• surveillance testing,

• staff education and training,

• emergency preparedness,

• radiation protection,

• record keeping and industrial safety

51

Overall Summary Overall Summary

This segment covered:

•How to compile and draw together all of the different information comprising the safety case. Which are the main components of the safety case

•How to use the safety case in different applications such as:

• Comparison of options

• Prioritization of data acquisition and research and development

• Facility design and operation

• Licensing

• Construction and commissioning

• Operation

• Monitoring

• Management controls

52

Segment SCD 4.3 Module SCD 4: Safety Case Segment SCD 4.3 Documentation and use of the safety case.

Documents

Transcript of Segment SCD 4.3 Module SCD 4: Safety Case Segment SCD 4.3 Documentation and use of the safety case.