Evolution of hazards over time

Sufficient margin in the design basis values can be included to accommodate evolution with time of the input data, or to take experience feedback into account. There is a balance between the extra cost linked to the overestimation of such parameters in the design phase and the hypothetical cost of future retrofitting of the research reactor to accommodate the evolution. 

Evolution of air traffic has to be anticipated, as well as the evolution of infrastructure such as the introduction of dam equipment on an undammed river or highway construction in valleys, which then leads to modification of the flooding parameter. An anticipation of the evolution of human activity should also be taken into account in the design parameters. 

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