Built-In Safety Margins

To be on the safe side, the stability tests are normally conducted at more stressful 

By running stability tests at these artificial conditions, a safety margin is built in by default. This fact has to be kept in mind when stability-testing conditions are being established and additional safety margins are regarded as necessary. 

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If route-to-route extrapolation implies a lower rate of dosing, this can be considered to provide a built-in safety margin and in such cases no assessment factor is needed, i.e., an assessment factor of 1 is appropriate. It is not appropriate to define a default assessment factor (ECETOC 2003). 

Any part of the chemical process plant is designed to contain hazardous chemicals under operational process conditions with a built-in safety margin. These margins are typically subject to rigid design standards. In this work deviations of the process parameters beyond these margins are called parameter excursions. Parameter excursions are quantifiable entities that have probability of occurrence [year ]. 

It is important to imderstand that much of this equipment is not specifically designed to operate under the conditions it is likely to meet in a coastal/maritime project. This misuse means that the safety margins built into the plant by the manufacturers, applicable to the normal field of operation, will to some degree be eroded. Some equipment has been specially modified to help it meet these exceptional conditions, but often still remains at greater risk than in its original design environment. 

In conclusion, storage arrays for new PWR hiel assemblies may be built with assurance of safety with respect to low-density interspersed moderation. Centier-to-center spacing in the arrays and array size may be considered as parameters which may be varied to contribute to the available safety margin but are not requirements. The degrees of low-density moderation which might lead to compromising safety in arrays are not achievable by accident. 

A graphic user interface (GUI) was built to make the C-V device software user friendly. The GUI shows the measured temperature, electrical conductivity, acoustic velocity, and the determined salt and inhibitor concentrations. By clicking on HSZ on the menu bar, a HSZ window will appear and the determined salt and inhibitor concentrations will be automatically fed to the integrated thermodynamic model. The hydrate phase boundary is determined by the model after the hydrocarbon composition is loaded. The determined hydrate phase boundary can be shown in a plot or saved in a Microsoft Excel data file. The hydrate safety margin can be calculated if the operating temperature and pressure are known. 

The MTR control rods are of two main classes, the shim-safety rods and the regulating rods. All of them are designed to lower the reactivity of the reactor when they are inserted, and when fully in, i.e., resting in their shock absorbers, they will Overcome ah excess reactivity of greater than 40X. It will be shown in Chap. 6 that it is necessary to have approximately 19% excess reactivity built into the reactor hence the control rods provide an adequate margin of safety. 

The size of this hidden area that does not conform to the prescribed model, is proportional to the appearance on paper of the margin that was built into create safety buffers the violation or deviation are in fact only defined in relation to a regulatory requirement (whether this is inside or outside the enterprise itself). If the regulatory requiranent contradicts an increasing demand for performance, the number of violations will automatically increase and the system will begin to migrate. 

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