Safety-related system

Design equipment to accommodate maximum operating envelope. Appropriate use of Safety-Related Systems (SRS) such as Safety-Instrumented Systems (SIS). 

The NPRDS collects failure data on safety-related systems and components. At present, more than 60 plants are reporting data. The data are compiled and disseminated in periodic report,s to the participants of the program and other potential users. In addition, special searches of tl may be requested by the... 

Real-time access to the data base is possible through a data base management system. In addition to safety-related system data, data for interfacing (auxiliary) system components are also available. The data base management system provides in-depth flexibility for generation of specific output reports. Although access has been limited to members of the Swedish Utility Consortium and the Swedish Power Board Directorate, a Reliability Data Book is available with generic failure rates based primarily on this data base. 

The failure data for these rates is obtained from maintenance work requests supplemented by incidence reports and Licensee Event Reports from the 1975-1980 time period. The work requests provide a complete history of all repairs performed at Oconee. They are not restricted to safety-related systems, they are written during all modes of unit operation, and they are not produced in response to licensing-based criteria. 

IEC (1998), IEC 61508, Functional Safety of Electrical/Electronic/Programmable Electronic Safety-related Systems, Parts 1-7, Geneva International Electrotechnical Commission. 

IEC 61508, 2000. Functional Safety of electronical/electronic/programmable electronic safety-related systems, Bureau Central de la Commission Electrotechnique International, Geneve. 

A process or a facility satisfies the single fault tolerance principle when it has been designed or equipped in such a way that a single fault does not lead to the occurrence of the undesired event. This applies also to safety-related systems. 

Draft Standard IEC 61508, "Functional Safety of Electrical/ Electronic/ Programmable Electronic Safety-Related Systems", (Contact BSI/IEC for availability)... 

The generic standard of the safety community is IEC 61508, Functional Safety of E/E/PE safety-related Systems. The engineering community has built a set of standards based on IEC 61508 for specific sectors, taking into account the experiences, background knowledge and requirements the process control sector, medical sector, nuclear, railways, and is still continuing (e.g., automotive in progress). But this standard takes only the safety view, security is not even mentioned ... 

Unfortunately, the gap has not been spanned by these approaches. As far as I know, only JRC Ispra has once financed a project of EWICS TC7 (European Workshop on Industrial Computer Systems, TC7, Safety, Reliability and Security, an expert group in this area), on Study of the Applicability of ISO/IEC 17799 and the German Baseline Protection Manual to the needs of safety critical systems (March 2003)(www.ewics.org) (3), where the gaps between the security standards and the safety-related system evaluation requirements have been analyzed for several sectors (medical, railways, nuclear, electric power networks) and in general. 

The standard gives guidance on E/E/PE Systems. The goal may be achieved by more than one safety-related system and by a bundle of measures, but always based on hazard and risk analysis, on getting the overall safety requirements right, and by developing a concept for proper safety requirements allocation. 

The safety lifecycle is a model for identifying the activities appropriate to safety-related systems... 

The security life cycle of safety-related systems has to take into account the complete IT-security management life cycle as addressed in ISO 17799 and many national IT Security Handbooks, equivalent to the safety life cycle of IEC 61508. IT-Security Management is a continuous process of... 

It has been demonstrated, that mass deployment of networked, dependable embedded systems with critical control functions require a new, holistic system view on safety critical and security critical systems. Both communities have to interact, communicate and integrate at the end. A unified approach to address the safety AND security requirements of safety related systems is proposed, based on the functional safety standard IEC 61508 and IT-Security management standards, handbooks and guidelines. 

IEC 61508, Functional Safety of E/E/PE safety-related Systems, Maintenance Group MT12, JTT4, Remote Access and Security ... 

International Electrotechnical Commission. International Standard lEC 61508 functional safety of electrical/electronic/programmable electronic safety related systems. Geneva. 2000. 

International Electrotechnical Commission. International standard lEC 61508 functional safety of electrical/electronic/programmable electronic safety related systems. Geneva 2000. Health and Safety Executive. Controlling the risks in the workplace. [Online]. 2015 [cited 2015 July. Available from http //www.hse.gov.uk/risk/controlling-risks.htm. 

FBTR has 36 neutronic and process parameters initiating reactor trip and has encountered large number of trips since first criticality. The paper also highlights several modifications affected in safety related systems for improved performance and safety reviews to reduce the parameters initiating reactor trip. 

Like other safety-related system properties that are ignored until too late, operators and human-factors experts often are not brought into the early design process or they work in isolation from the designers until changes are extremely expensive to make. Sometimes, human factors design is not considered until after an accident, and occasionally not even then, almost guaranteeing that more accidents will occur. 

Methodology of the system design is in compliance with normal industrial standards meeting simultaneously requirements for the safety- related systems in NPP. 

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. 

Operating Experience of Digital Safety-Related System of Kashiwazaki-Kariwa Unit No.6 and 7... 

B) Safety related systems, participating in the implementation of safety-related functions ... 

Compliance with this regulation was focused upon in establishing the design basis and system requirements both for the innovated plant I C system as a whole as well as for the I C portions of the individual plant safety and safety-related systems. Design and implementation of the refurbished I C systems important to safety will have to meet, in the first place, all the applicable requirements of this... 

There are some considerations for selecting components and sub-systems to be used in a SIS. The first option is that the components be designed in accordance with lEC 61508-2 (requirements for electrical/electronic/programmable electronic safety-related systems) and lEC 61508-3 (software requirements). The second option is to use components and sub-systems that are known to be reliable through extensive use in similar service and in a similar environment. 

Systems containing radionuclides and "safety-related" systems are minimized and contained within a well defined Nuclear Island which is separated physically and functionally from the remainder of the facility. This allows the construction and operation of the other areas in accordance with conventional standards and practices. 

Safety-related" systems, structures, and components, which make up the set of equipment capable of performing all the functions required to limit releases under accident conditions to those allowed by lOCFRlOO. 

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