Possible future accidents

They should be prevented so they never enter the 

A sequence like the one described might happen, for example after a small break LOCA, after a PRISE (primary to secondary leak) accident, after an ATWS or after a total Loss of Feed-Water. This possible phenomenon must be taken into account in the Emergency Operating Procedures, since fast operator action will prevent the accumulation of unborated water slugs. As in many 

In some plant (e.g. some VVERs), this phenomenon is prevented by design since the ECCS injection point is located in the loop seal of the cold legs, where the unborated water would accumulate upon actuation of ECCS, the boron concentration in the slug would be rapidly increased, thus preventing any recriticality danger. 

Uncontrolled leak in the vessel bottom A 5 cm diameter hole in the vessel bottom would be much more dangerous than a 10 cm hole in the vessel head. In fact, a hole in the vessel bottom 

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For many years the usual procedure in plant design was to identify the hazards, by one of the systematic techniques described later or by waiting until an accident occurred, and then add on protec tive equipment to control future accidents or protect people from their consequences. This protective equipment is often complex and expensive and requires regular testing and maintenance. It often interferes with the smooth operation of the plant and is sometimes bypassed. Gradually the industry came to resize that, whenever possible, one should design user-friendly plants which can withstand human error and equipment failure without serious effects on safety (and output and emciency). When we handle flammable, explosive, toxic, or corrosive materials we can tolerate only very low failure rates, of people and equipment—rates which it may be impossible or impracticable to achieve consistently for long periods of time. 

Where does all this leave us There are two possible reasons for conducting an accident investigation (1) to assign blame for the accident and (2) to understand why it happened so that future accidents can be prevented. When the goal is to assign blame, the backward chain of events considered often stops when someone or something appropriate to blame is found, such as the baggage handler in the... 

One consequence of the completeness of a STAMP analysis is that many possible recommendations may result—in some cases, too many to be practical to include in the final accident report. A determination of the relative importance of the potential recommendations may be required in terms of having the greatest impact on the largest number of potential future accidents. There is no algorithm for identifying these recommendations, nor can there be. Political and situational factors will always be involved in such decisions. Understanding the entire accident process and the overall safety control structure should help with this identification, however. 

The analysis of past accidents may provide lessons learned to avoid the recurrence of accidents and to improve emergency response in future accidents. In order to obtain data about the vulnerability of the equipment items and to get a possible correlation between the lightning severity and the possible damage states, the historical analysis of past accidents was used as a starting point. In fact, the review of records on industrial accidents triggered by lightning events may allow the identification of ... 

Management will make every effort to provide adequate safety training to employees prior to allowing an employee to begin work. Employees in doubt about how to do a job or task safely are required to ask a qualified person for assistance. Employees must report all injuries and unsafe conditions to management as soon as possible so that corrective measures can be taken to prevent future accidents. 

For his part, the employer must take reasonable steps to investigate the circumstances of every such accident notified to him and, if there is any discovered discrepancy between his findings and the information provided by the employee, must record that discrepancy for possible future reference. 

The methods and models [33,35] used to assess doses to members of the public from normal discharges are not appropriate for emergency situations, in which the maximum use needs to be made of the available information, from a limited number of measurements, to estimate off-site consequences promptly. These methods should include provisions to project off-site consequences that could arise as a result of the conditions at the facility (e.g. in the case of unmonitored or possible future releases). These projected off-site consequences could be precalculated doses for different accident conditions, as provided in Ref. [10], or computer models such as INTERRAS [10]. The dose projections should be as realistic as possible, and in any case doses for situations in which persons might be in danger of being harmed should not be underestimated. 

Factual information needs to be collected where there is the likelihood of some form of claim either against the organization or by the organization (e.g. damage to equipment). This aspect should be considered as a second objective in accident investigation, the first being to learn from the accident to reduce the possibility of accidents occurring in the future. 

Make immediate corrections where possible in order to avoid future accidents. 

Schofield, D., and J. Noond. 1999. Accident reconstruction possible futures. Paper presented at Senior Accident Investigators Conference. April 24-25, Essex Police Training School, Chelmsford, Essex. 

The Health and Safety File is maintained to record the possible future health and safety risks that will need to be avoided or contained during the subsequent use of a building and any further modifications and adaptation. The File provides structured information to support the effective management of health and safety risks throughout the remaining lifetime of a building. The use of Health and Safety Files over time should be monitored against accident frequency and safety records. This will be valuable in two ways. First, to understand the effects of the File... 

All of these measures presumably have the same objective, namely, to provide information that will enable the prevention of future accidents. Using the PDSA approach to safety improvement, measurement is critical, because without good measurement neither planning nor study is even possible. 

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