Probability screens

System event trees connect to the containment event tree with a large number ot sequences fonned by different combinations of events. The number of sequences is made tractable by grouping sequences in release categories - a process called binning. Two approaches to binning are 1) probability screening and 2) plant-damage bins. 

Fig. 4. Probability screens (a) hi-prob sizer (b) Ropro screen.

National Coal Board. Their Rotating Probability Screen... 

This program uses TrueType fonts to display information in each window. When you print these windows, you need to make sure that the Print TrueType fonts as Graphics option is enabled under the Printer Setup options. Options vary for various printers and their corresponding printer drivers, but most printer drivers either have this option or (less commonly) print TrueType fonts as graphics all the time. If this option is not selected, the printer will probably pick one of its built-in fonts, causing the printout to look different from what is displayed on the screen. 

In April 1982, a data workshop was held to evaluate, discuss, and critique data in order to establish a consensus generic data set for the USNRC-RES National Reliability Evaluation Program (NREP). The data set contains component failure rates and probability estimates for loss of coolant accidents, transients, loss of offsite power events, and human errors that could be applied consistently across the nuclear power industry as screening values for initial identification of dominant accident sequences in PRAs. This data set was used in the development of guidance documents for the performance of PRAs. 

If the positive potential changes are very small and confined to a few points on a small unprotected structure, it may be practicable to reduce the potential at these points by installing reactive anodes. The anodes will probably be most effective if they can be buried between the two structures. In some circumstances a similar screen of zinc, aluminium or steel may be installed between the structures. The screen must be electrically connected to the unprotected structure since it is installed with the object of providing an electrolytic path to earth for the interaction current. 

Figure 1,8, for example, plots the probability that a cell has value 1 at time t4-l - labeled Pt+i - versus the probability that a cell had value 1 at time t -labeled Pt - for a particular four dimensional cellular automaton rule. The rule itself is unimportant, as there are many rules that display essentially the same kind of behavior. The point is that while the behavior of this rule is locally featureless - its space-time diagram would look like noise on a television screen - the global density of cells with value 1 jumps around in quasi-periodic fashion. We emphasize that this quasi-periodicity is a global property of the system, and that no evidence for this kind of behavior is apparent in the local dynamics. 

Once hits have been identified, they must be confirmed. The test data obtained from a screen form a normal distribution. One criterion for determining possible active molecules is to retest all initial values > 3 ct units away from the mean. This will capture values for which there is >99.3% probability of being significantly greater than the... 

The Kel-F polychlorotrifluoroethylene view ports let us see what is happening on the hydrogen side of the screen (see later discussion). If it were really necessary to view the fluorine side, sapphire or diamond windows could probably be used. It is difficult to see below the electrolyte level of an operating cell because of gas bubbles. 

Figure 124 shows some details of the cell interior. The skirt is a solid Monel alloy sleeve extending about 2 cm below the electrolyte. (Teflon and Kel-F fluoropolymers could not be used as skirts for extended periods because they react with fluorine at the temperatures used they could probably be used as screens, however.) The screen (not shown) is an extension of the skirt. It consists of a Monel alloy sleeve with numerous 1-mm holes. The skirt and screen float electrically. They are bipolar and... 

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