Particular risk analysis objectives

Item characteristics (e.g. hazardous materials or working practices) if the aim in Step 2 required these to be addressed as well. These hazards could be identified via hazard identification tools/techniques such as the particular risk analysis, HAZOP, etc. (see Appendix A). Each hazard must then be allocated with either a numerical or a qualitative safety objective, which is agreed with the applicable airworthiness authority. 

An important and difficult task is concisely translating your requirements into study objectives. For example, if you need to decide between two methods of storing a hazardous chemical in a plant, the analysis objective should precisely define that what is needed is the relative difference between the methods, not the more general I want to know the risk of these two storage methods. And asking your QRA team for more than is necessary to satisfy your particular need is counterproductive and may create unnecessary liabilities. For any QRA to efficiently produce the necessary types of results, you must clearly communicate your requirements... 

Integration of or into other tools, particularly systems modeling and risk analysis tools, as the tool is an object-oriented environments, where a requirement is defined as an object with its own attribute table. The attributes can be model attachments developed within other tools and exported into TRACE. They can also be a set of original requirements de fined in a document that is used as a support for the definition of the requirements modeled in TRACE. 

Real-world safety cases are sometimes based on deterministic arguments that particular failures cannot happen. But there are deep philosophical objections to such arguments, since no-one could realistically claim perfection for any stage in a development chain, let alone the whole of it. Increasingly - especially since [WASH-1400] - safety cases use probabilistic arguments - or Probabilistic Risk Analysis (PRA). This is paralleled by moves to educate the public in the concept of risk - e.g. [HSE 88]. 

Bayesian methods are very amenable to applying diverse types of information. An example provided during the workshop involved Monte Carlo predictions of pesticide disappearance from a water body based on laboratory-derived rate constants. Field data for a particular time after application was used to adjust or update the priors of the Monte Carlo simulation results for that day. The field data and laboratory data were included in the analysis to produce a posterior estimate of predicted concentrations through time. Bayesian methods also allow subjective weight of evidence and objective evidence to be combined in producing an informed statement of risk. 

The technical staff of the Department became concerned that the proposed CERCLA lai uage would not only impose a greater burden on the Department s environmental restoration efforts, substantially raising the costs without commensurate benefit, but also that there may be no way to accurately verify that the cleanup standard had been reached. Two key factors, background radiation (including fallout) and laboratory or instrument capability were of particular concern. A study, entitled "Preliminary Analysis of the Technical Feasibility of Achieving Various Residual Risk Standards for Cleanup of Radionuclides in Soil" [6], was canied out to determine the scope of the problem. It had two principle objectives ... 

A6. As stated in para. A3, the attaiiunent of the safety objectives for a particular nuclear installation is demonstrated by means of a safety analysis. Ideally, diis safety analysis should include all events, sequences and processes where failures or combi-rratiorts of feiluies could potentially have radiological cortsequences. In practical aj licatiorrs, it is not possible or necessary to achieve this degree of completeness. Whedier the safety analysis is carried out by probabilistic methods or by the conventional methods of detailed engineering analyses (deterministic methods) it will, of necessity, be based on a selected set of scenarios (combinations of events, sequences and processes). The selection must be made in such a way that the major contributors to risk are covered as far as is reasonably achievable. Safety analysis, i.e. the demonstration that the types of risks to be considered have been reduced to tolerable levels, as discussed in para. A3, should be performed using proven methods and with appropriate peer review. 

A related topic is also that the risk analysts themselves might be biased . For instance, could the risk analysts have personal interests for a decision to enter In Amenas, or a particular security technology This issue is often seen in political decisions. Administrative staff performs the analysis, prepares the case and advises the elected officials on a decision. Of course the administrators try to be objective in their assessment, but they too have political or financial interests of their own which may influence the analysis and advice. The manager must also take similar concerns into account when presented with a risk description, as such biases could lead to unpleasant surprises. 

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