Accident Severity Criteria

Next, we ask whether the LTI-rate is a valid indicator of the risk of losses dne to accidents. This criterion is more problematic, since the LTI-rate is insensitive to the severity of the injuries. An eye injury resulting in a few days of absence and a severe fall injury with many months of sick leave connt equally when calculating the LTI-rate. It is questionable whether the LTI-rate is a valid indicator of the risk of losses due to accidents. Other SHE performance indicators that we will look into in the next Section are better suited as to validity, since they account for the degree of harm (e.g. number of days of absence). 

Leachability of a waste form is perhaps the most important criterion in considering accident situations. In the absence of salts, some of our cement products may approach the low leachability of glass. After experimenting with several methods for measuring leach rates, we selected the... 

In June 1985, an Italian criterion was announced (Petrangeli and Zaffiro, 1985) for the limitation of the consequences of a severe accident by simple plant modifications and by a management system of the same accidents ... 

The question that this criterion intended to answer was the following What are the maximum realistically thinkable releases, in severe accident conditions, which are consistent with the best use of the capabilities of present design plants, if a structure of accident management (procedures, equipment, training) is created ... 

In chapter three, the theoretical background to all the potential macro-factors that could contribute to road accidents was presented. The relationship between each factor and the probability that road accidents may occur on the national level was conducted. One special criterion to select suitable indicators was used. This has enabled me to determine the key macro-performance indicators in road safety. It has become clear that the chosen indicators must be easy, available, measurable, and comparable worldwide. Moreover, these indicators must be able to indicate/monitor the country s progress over time in road safety and allow international comparisons. The obtained set of indicators was listed and summarised in Table 3.2. The next step was to understand and explain the main published macroscopic studies and models that are used in describing and comparing the road safety development internationally. I have divided the reviewed models into cross-sectional models (time-independent models) and (time-dependent models). A starting point in this direction was to investigate Smeed s equation, particularly in the relation between motorisation and fatality rates. Several models for... 

For severe accidents, the regulatory body may specify a risk criterion or a criterion associated with specified releases of radioactive substances. 

A percentage of accidents involving the most vulnerable users was calculated for each zone. The criterion representing uiban intensity was tested using several types of weights (Figure 2.3). 

The reporting criteria define what types of events are to be reported. Such criteria may be formalised but may also be informal and based on a shared understanding within the organisation. Reporting criteria for accidents are usually defined on a consequence scale of measurement such as whether the accident involves lost time after the day of the event or not (yes/no). This particular criterion is relatively simple to communicate and apply, since it also has implications as to the victim s right to compensation for sick leave. A problem is its limited coverage. Minor accidents with potentially severe consequences will pass undetected and we will miss an opportunity of learning from such experience. 

The short-term permeation rate of hydrogen from the ZrHi 7 layer at an accident is also calculated. The hypothetical scenario in which the temperature of the ZrHi 7 layer is suddenly increased to 1,260°C (the criterion of the cladding surface temperature at the LOCA is created, and the void reactivity is analyzed). The results are shown in Fig. 7.11. It can be seen that several hours are needed to lose one third of the hydrogen from the layer. That is much longer than the time required for the control rod insertion and borated water injection. Therefore, the hydrogen loss does not impose any severe problem for reactor safety. 

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