Safety-related control systems mechanical

The integrity of pipelines depends upon conect design, including materials selection, support and protection from mechanical damage. Depending upon tlie gas, routine inspection and maintenance may be supplemented by the provision of gas detection and alarm systems. Other considerations are exemplified by the safety-related controls on the transportation of domestic gas via pipeline systems summarized in Table 15.17. 

It has been required to take into account the feedback of experience related to the mechanical problem of isolated safety injection lines when small leaks through the isolation valves may occur ( Farley-Tihange problem responsible for several small breaks on the safety injection piping). Implementation of on-line temperature and pressure measurements will allow to identify any small leak through the isolation valve to the primary circuit and the dedicated corrective actions can be taken to evacuate the leak to the Chemical and Volume Control System. ... 

Fast forward a decade and a half to 1998 and echoes of the Markham report resonate in the standard EN 61508. This standard, called Functional safety ofelectrical/electronic/program-mable electronic safety-related systems, was developed in response to an increasing number of industrial accidents whose cause was attributed to Programmable Electronic Systems (PES). The increasing trend was to use the PES to perform the safety and plant control functions, and move away from mechanical or hardwired electrical controls. While the estabhshed method... 

Since the release of EN 61508, there have been rafts of other standards developed that address specific industries and other disciplines. Two standards that are commonly asked to comply with in designing hoisting are EN 62061 Safety of machinery Functional safety of electrical, electronic and programmable electronic control systems, and EN ISO 13849-1 Safety of machinery Safety-related parts of control systems. The latter standard caters for design of safety systems irrespective of the technology used, whether it is electrical, mechanical, hydraulic, pneumatic etc. 

The performance of reactor systems, sodium systems, control rod drive mechanisms and other safety related systems and auxiliary system were generally satisfactory. The primary and secondary sodium purity was maintained below the plugging temperature of 105 C. The four sodium pumps and Aeir drives are operating well and have logged 83,293 h, 70,615 h, 88,878 h 69,201 h. 

Generic Safety Issue (GSI) 064 in NUREG-0933 (Reference 1), addresses the establishment of guidance for the identification of the mechanical sensing lines which interface with safety-related instrumentation and controls systems. 

In the field of science and research. Dr Sinay has been working with mechanical dynamics as a source of technical risks, optimization of risk management systems for technical systems and occupational health and safety, problems of control integrated systems, issues of safety and security, and with processes of quality assessment mainly in the field of university education. He has tutored thirteen doctorate students, two of them inaugurated as professors in fields related to safety and one promoted as a senior lecturer in the field of safety of technical systems. He is... 

Ill-103. Reactivity control system, reactor shutdown system The function of the mechanical and electrical design shall be described. The description shall include the materials and dimensions and shall be supported by drawings. The reactivity control mechanisms and their instrumentation, such as their position or status (coupled/decoupled), should be presented, together with their insertion time and interlocks. The effects of corrosion, fatigue, neutron doses, etc., on the lifetime of the mechanical and electrical components shall also be discussed. The safety related design parameters should be presented, such as ... 

Interlocks provide logical constraints within control systems and often provide a safety related function. These functions may be embedded within the basic control system in the form of software or they may be relay or mechanical interlocks directly linked to the equipment. They can therefore be considered as providing a layer of protection and their degree of independence must be evaluated in each particular application - in each application decide if the interlock is part of the control system, an independent safety device or part of the SIS. 

Parallel Track Mechanism A U.S. Public Health Service policy that makes promising investigational drugs for AIDS and other HIV-related diseases more widely available under parallel track protocols while the controlled clinical trials essential to establish the safety and effectiveness of new drugs are carried out. The system established by this policy is designed to make drugs more widely available to patients with these illnesses who have no therapeutic alternatives and who cannot participate in the controlled clinical trials. 

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