Design system safety assessment report

At this point the author of the PRA must ensure visibility of these recommendations to all relevant stakeholders. Consideration needs to be given to issuing the first draft of the PRA as early as possible, especially if the output influences the requirements management process (see Fig. 1.3). This may take the form of a stand-alone report or may be contained within any interim updates of the System Safety Assessment (i.e. PSSA is the first issue, SSA is the final issue, with as many ISSAs as required to keep track with the evolving design and maturing System Safety Assessment). 

System safety should be involved in the PDR, typically making a presentation summarizing the safety effort to date, the DSFs in the system design, and the current level of mishap risk which the design presents. System safety provides, as a minimum, a subsystem hazard analysis (SSHA), SHA, safety assessment report (SAR), and final safety requirements for this review. 

The System Safety Assessment (SSA) shall answer the question Does the implemented system achieve tolerable risk The system must inqilement all safety requirements and must provide the intended functionality such that the remaining risk is kept at an acceptable level. In order to assure this, test methods such as those proposed by lEC 61508 are applied. Thereby it is verified that the safety goals are achieved and that the safety requirements are considered accordingly in the design. SSAs are consequently performed in an iterative way over the remainder of the system life cycle. In this context the safety case report has to be regarded as a living document that must be kept up-to-date especially with regard to modifications of the system or the system environment. 

Hazard Analysis—The determination of material, system, process, and plant characteristics that can produce undesirable consequences, followed by the assessment of hazardous situations associated with a process or activity. Largely qualitative techniques are used to pinpoint weaknesses in design or operation of the facility that could lead to accidents. The Safety Analysis Report (SAR) hazard analysis examines the complete spectrum of potential accidents that could expose members of the public, on-site woikers, facility workers, and the environment to hazardous materials. 

Early reactor safety assessments [S-1] hypothesised that severe accidents would entail the prompt release of a significant fraction of a bounding radionuclide (t5q)ically iodine) to the reactor containment. Safety systems were designed, then, for massive, immediate response to this release. Now, it is understood that radionuclide releases will take place by multiple processes over protracted periods and will involve many different radionuclides in different chemical and physical forms. Mitigation methods will have to operate for long periods and may have to change as the sources of radionuclides vary. The inventories of radionuclides available for release from reactor fuel under accident conditions and the processes that lead to releases of these radionuclides are discussed in the next subsections of this report. 

All documents created for a project should be reviewed by an independent person from the creator of the document. At certain stages of the lifecycle, the standard recommends that a functional safety assessment be performed by an assessment team that contains at least one senior, independent, competent person. This independent person can be an employee of the company or a contracted third-party, as long as the reviewer understands the process hazards, the company s management system, the full SIS lifecycle, and the fundamentals of appropriate design, installation, operation, maintenance, testing, and reliability. This person should not be part of the project team, report to project team management or plant operations, and should have the authority to prevent the project from proceeding if deviations are not addressed. 

Melvin, J.W, King, A.I., and Alem, N.M., AATD System Technical Characteristics, Design Concepts, and Trauma Assessment Criteria, AATD task E-F Final Report, DOT-HS-807-224, US Department of Transportation, National Highway Traffic Safety Administration, Washington DC, 1988. 

In short, the accident risk assessment provides a comprehensive, detailed evaluation of the overall accident risk associated with the operation and maintenance of a specific facility, including its systems, equipment, and hardware. It incorporates the results of integrated hazard analyses, recommended design changes, hazard reports, and procedural or administrative tools that will eliminate or reduce the risk of these hazards, operational flowcharts, safety-critical procedure lists, and other such information pertinent to overall assessment of accident risk. 

GLP is a quality system of management controls for laboratories and research organisations involved in nonclinical studies conducted for the assessment of the safety of chemicals to humans, animals and the environment it is designed to ensure the consistency and reliability of results, and specifies the manner in which studies are to be planned, performed, monitored, recorded, reported and archived. 

Despite the obvious importance of ISD, there has only been limited work for developing tools that support the assessment of IS. INSET was developed to promote IS principles, and contains a set of tools which support the adoption of IS principles into process development and design (Malm n et al., 1995 van Steen, 1996, Turney et al. 1997). Recently, an expert system that supports ISD by identifying safety issues and proposing inherently safer alternatives was reported (Palaniappan et al., 2002a 2002b). 

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