System Safety Assessment process verification

The proposed methodology also covers the developing of conceptual scheme, criterions, requirements and elements of A SW verification and validation assessment process technology for safety-related systems, as well as recommendations for its utilizations in practical applications. The presented results are obtained during the generalization of practical experience of expert analyzing of real NPP I C A SW, in particular ASUT-IOOOM system for Zaporozhey NPP. 

Finally, the Safety Case is compiled to argue that the system is safe. The safety case is derived from the safety concept and extended by results of the verification validation process to prove that the safety requirements have been fulfilled. A safety case is a concept applicable across all domains. However, in aerospace and railway a so-called Safety Assessment is required additionally to show the conformity to the standard [5]. The evidence for system safety provided by the safety case forms the basis for safety certification. 

Surprisingly the standard does not require the product itself as an input for the activity, which does not mean that the Functional Safety Assessment could be simply reduced to a document check. A couple of further requirements, which result from the verification and validation activities and their requirements, disagree. Also the required assessment plan in Chap. 5.5.5, which results from the single requirement that the Assessment of Function Safety needs to be planned at the beginning of system development, indicates that the entire product development process needs to be assessed so that proven evidence for the Functional Safety Assessment could be provided. 

The process of NPP I C systems V V and expert analysis of V V includes the stages of verification and validation and expert analysis of V V both algorithms and software (A SW). The quality of A SW V V execution is very important for the computer-based critical I C systems reliability and safety ensuring. The requirements for verification have actually become more strict and methodology of V V is the subject of regulatory bodies assessment. The problems of regulation of V V are inseparable components of both national and international standards in critical engineering [1-3],... 

General scheme of the process of A SW verification and validation assessment for safety-related l S systems is based on the following principles ... 

Data used by a safety-related system should be classified based upon the uses made of the data and the way in which the data influences the behaviour of the system. The nature and influences of data faults will also vaiy with the form and use of the data within a system. Data integrity requirements are essential if the suitability of data models is to be assessed. This paper has presented a process by which these data integrity requirements may be established. Additional design analysis may identify that the structure and composition of the data set or that data from the real world cannot be obtained in either the quantity, nor of the requisite quality. These data integrity requirements may also be used to identify verification and validation requirements for the system. 

Aerospace has continued to provide many engineering, design, and safety services to the Air Force for more than 40 years. One of its chief functions is to perform launch verification and readiness assessments for all Air Force space launches. Aerospace s launch verification procedure is veiy broad, beginning with analysis of launch system design. Aerospace independently tests physical components and software, checks manufacturing processes, and verifies correct assembly of the launch vehicle. Finally, Aerospace delivers a formal launch verification letter to the Air Force s Space and Missile Systems Center, monitors the launch, and analyzes launch and post-launch data (Tomei, 2003). All of the functions are redundant in the sense that Air Force and contractor personnel also perform most of the same functions. Aerospace s launch verification serves as an independent, objective assessment of launch safety that the Air Force uses in conjunction with its own analyses in making launch decisions. 

Establish an effective safety management system/process. Nominate key roles/ responsibilities. Define approval signatories - especially for safety reports. Establish independent verification/audit to reduce chance of undetected error. Establish a workforce-wide commitment to product integrity. Learn from previous mistakes. Initiate a documentary audit trail (identify, log and track all hazards). Airworthiness and safety must be foremost in the minds of the entire organisation. Furthermore, as many legal cases turn on documentation, it is essential that risk assessment activities and choices are documented and that records are kept. ... 

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