Accumulated accident experience

In this chapter, we will look into the establishment and use of accident and near-accident databases. Experience stored in such databases will help us in answering questions like  

The database contains accumulated experiences on accidents and near accidents. Answering questions is one of the different uses of this type of database. In this application, the user queries the database in order to retrieve information about accident and near-accident cases. Experience shows that the users are mainly concerned with finding individual accident cases (Kjellen, 1987). There are other means as well  

The second and third uses illustrate the support and rationalisation that computerisation offers the SHE administrator. We will present examples of these applications in Part VI. A more basic administrative function is to keep track of the accident and near-accident records and to help distribute these records within the company and to the insurer and the authorities. 

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There is another possible way to ensure a systematic use of the accumulated accident experiences within a company. Figure 15.10 shows the application of experience carriers as an intermediate link between the accident database and the end use. This involves improvements of safety in production systems in operation or in the design of new production systems. An experience carrier here expresses a company s collective experiences in a format that... 

A traditional means of implementing accident experiences in production systems in operation is to update the work instructions. These documents will successively accumulate accident experiences and become experience carriers for use in the training of new employees and in the follow-up of safe behaviour. Modifications of design are also a means of storing the accident experiences in the company s collective memory as long as the changes represent the company s best practice and are used in subsequent design work. 

Part III leads the reader through a number of different methods for the collection, analysis and use of data on accident risks. The focus is on how to prevent accidents through learning from individual events and conditions and from accumulated accident experience from many incidents. The advantages and disadvantages of the different methods are discussed. 

Construction engineering is an activity throughout the development process of human society. We human moved into skyscraper from the cave by accumulating successful experience and we can also prevent the accidents from recurring via the analysis of previous failures to master relevant laws. 

The final authority on the durability of catalysts is performance in road vehicles. Such data have been rapidly accumulated by the various automobile manufacturers in recent months. This data takes into consideration all the accidents of everyday usage, serving to test how much abuse the catalyst can withstand and still perform its duty. Experience has shown that fresh oxidation and reduction catalysts by a large variety of formulations from many manufacturers would indeed perform their duty. Many oxidation catalysts perform well enough at 25,000 accumulated miles to satisfy the requirement of 0.41 g hydrocarbon/mile and 3.4 g CO/mile, but few would perform well enough at 50,000 miles without maintenance and adjustment of the engine. Many such vehicle endurance tests have to be terminated because of malfunction of the engine or the auxiliary equipment. 

For example, a traditional checklist is, by definition, based on the process experience the author accumulates from various sources. The checklist is likely to provide incomplete insights into the design, procedural, and operating features necessary for a safe process. The what-if part of the analysis uses a team s creativity and experience to brainstorm potential accident scenarios. However, because the what-if analysis method is usually not as detailed, systematic, or thorough as some of the more regimented approaches (e.g., HAZOP study, FMEA), use of a checklist permits the PrHA team to fill in any gaps in their thought process. 

Experience accumulated in the process of the advanced codes application for various simulated accidents and transients allows us to believe that these codes can be used, with a great degree of confidence, not only for the Safety Reports purposes, but also to support simulators which will be in operation at both Czech power plants and also for new type of reactors. 

Reference is made several times in this book to an organization s safety culture and how it impacts on the injury experience attained, favorable or unfavorable. Since causal factors for incidents resulting in serious injury are largely systemic and their accumulation is a reflection of the organization s safety culture, that subject must be explored. Comments made on organizational culture in the August 2003 Report of the Columbia Accident Investigation Board on the Columbia space ship disaster are pertinent here. They follow. 

Willard Libby discussed with the Joint Committee what could happen in the "worst possible case" reactor accident that would totally release its fission products. But he differentiated between maxumun possible damage and the more likely probable damage in the event of a reactor failure. He also testified that estimates of consequences were necessarily theoretical because, fortunately, "practical experience with reactor failure has been minimal." The danger arose from the fission products accumulated during the operating period, and not just from the additional fission products generated instantaneously in a runaway accident. ... 

By applying computer support, our immediate aim is to make the feedback to decision-makers of information about accident risks quicker and more efficient. A further aim is to reduce man-hours needed for the administration of reports. Computer support also makes information retrieval much easier, and the accumulated experience from SHE practice will be available through a few keystrokes. Long-term effects include a reduced risk of accidents, improved production regularity, more efficient safety work, improved knowledge and motivation, improved goodwill, etc. 

The first experiment series included five SBLOCA tests with break in one hot leg of PACTEL. Three break sizes were used. Three tests included secondary system depressurization as an accident management measure. In all tests, only PSIS provided ECC water to the core. The primary pressure used in the tests was lower than the nominal operation pressure of PACTEL. Maximum operation pressure of the passive accumulators determined the upper limit of the experiment pressure (3.8 MPa). 

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