System safety requirements, establishing

The safety/risk criteria. The safety/risk criteria establish the top-level system safety requirements, or objectives. Regulatory authorities may have different definitions for the various categories of hazards/accidents. To be able objectively to distinguish and evaluate the various hazards present, it is important to define the exact terminology and to allocate a measure of performance. This is an important (and arguably most neglected) topic as it is the safety acceptance criteria the system is expected to achieve, and hence the measure (or standard) the assessment will compare the system against. For more detail on safety criteria, see Appendix B. The system level. Define the systems level at which safety is to be assessed. The importance of this step is explained in Section 8.3 above. A safety assessment by a supplier of a component (e.g. a flare dispenser) will vastly differ in scope and approach to a safety assessment for a product (e.g. an aircraft) or user system (e.g. a facility). 

Establish by a consensus of the national codes and standards development organizations such as the CDO or SDO that will have the lead in the development of codes and standards for establishing safety requirements for specific components, subsystems, and systems (as shown in the templates) and the organizations that will work collaboratively with (or in support of) the lead organization. 

System engineering starts with first determining the goals of the system. Potential hazards to be avoided are then identified. From the goals and system hazards, a set of system functional and safety requirements and constraints are identified that set the foundation for design, operations, and management. Chapter 7 describes how to establish these fundamentals. 

The purpose of the Decree and the four regulations is threefold (Sect, i of the Decree) To further a high standard for safety, achieve a systematic implementation of measures to fulfil safety requirements and objectives, and further develop and improve safety standards. While the first and last of these objectives aim directly at the fundamental objective of any safety legislation, the second objective points in a slightly different direction in order to be able to systematically implement relevant measures to comply with safety requirements, the responsible party has to establish an administrative and organisational structure for this purpose. This objective thus constitutes the inception of the internal control system (Subsection 5.1.2 (b)). 

The most general indirect safety requirement is the provision that obliges the party responsible to establish, follow up and further develop a management system designed to ensure eompliance with requirements in the health, safely and environment legislation . This is the very basis for the internal control system. 

The system of regulatory documents on nuclear power plant safety is complemented by the system of state standards developed and established by the State Committee on Standards (Gosstandart of the USSR). The system of standards extends the system of regulatory documents by ensuring nuclear plant safety through establishing requirements for many components, materials, processes, etc. 

For maintaining safety during shutdown, daily work co-ordination of an outage is essential. It is recommended that each plant establish an outage co-ordination team with adequate knowledge of operations, safety systems and safety functions success requirements. This team should co-ordinate daily activities, with a focus on safety requirements and safety systems availability. The team should be headed by an expert with shift supervisor experience and/or license. 

The aircraft-level FHA identifies and classifies faiiure conditions associated with aircraft functions (i.e. Level 4 functions in the example Fig. 1.1) and is used to support identification of possible multiple system failure conditions. The ciarifications of these failure conditions subsequently establish the safety requirements (or derived safety targets) that the aircraft must meet. 

The system/subsystem-level FHA (i.e. Levei 3 in the exampie Fig. 1.1) considers failure or combinations of system failures that affect that system s function. The clarifications of these failure conditions establish the safety requirements that the system must meet... 

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