Evaluation of site characteristics

The extent of a site survey can be defined in relation to the hazard category of the facility. The following criteria can be used  

The extent of the survey is based on regional studies, with the requirements for data quality and quantity set forth in Refe [1,6]. The investigation is site-specific and covers an area within an approximately 50 km radius of the site. This area may be extended to compensate for lack of data in the time record (see Section 6.2). It may be smaller if the area is not populated and possible causes of events do not exist. The record length to be considered for site-specific evaluation is chosen with reference to the return period selected for the design basis. Appropriate extrapolation techniques have to be applied and validated. The projected growth of population around the site during the lifetime of the facility is evaluated. 

The survey s extent will be based on expert judgement to be used as confirmation of the hazard proposed in the national building codes. The following sections deal with general considerations on site evaluation for hazard category 1 and 2 facilities. For hazard category 3 facilities, site evaluation may correspond to the national practice for a conventional risk facility. 

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