- 19 - exercises (every 4 years at Le Blayais) supplemented by partial exercises (deployment of pumping resources or "mini" cofferdams3 every year at Le Blayais). Maintenance and monitoring of the equipment is usually the responsibility of joint teams (in charge of the daily rounds). ASN finds that most of the sites offer a satisfactory response to this problem. 2.1.3 Special operating rule in the event of flooding The EDF head office departments issue operating memos called special operating rules (RPC), to deal with the risk of flooding on vulnerable sites. These rules are mandatory and must be applied by the sites (in other words the requirements must be incorporated into the operating instructions applicable to the site) no later than 6 months after they are received. These reports are regularly updated to take account experience feedback on the one hand and the results of the vulnerability studies on the other. National doctrine is implemented by most of the sites, albeit sometimes belatedly (Bugey, Blayais). However a number of discrepancies were detected by the inspectors: inconsistent alert criteria (Blayais), a waiver in place for several months with no means of mitigation implemented (Belleville), inconsistency with the requirements of the PUI (Bugey), absence of Météo France alert because no agreement in place (Cattenom), and RPC requirements not fully implemented (Saint-Alban). Some sites have not adopted the latest version of the RPC and plan to do so in the coming months (Tricastin in progress, Dampierre in May 2012). On the Gravelines site, the RPC has not been applied since 2008, and has since then been replaced by a new RPC, issued in 2010, which has not been implemented either. Finally, certain new applicable RPCs radically modify the scenarios; for example, in Tricastin, the site is now considered potentially susceptible to isolation and exposure to a loss of off-site power supply in the event of flooding, which was not the case in the procedures in effect on the day of the inspection. Certain analyses would benefit from being carried out systematically when the RPCs are implemented locally, but are not (no analysis of the discrepancies between the different versions carried out in Chooz, no analysis of the impact on socio-organisational and human factors in Gravelines). ASN therefore considers that the special operating rules in the event of flooding could be better implemented on the sites. The operating procedures when they do exist mention numerous actions to be taken depending on the alert levels. For example, at Belleville, there is provision for a variety of measures to isolate the site and guarantee its electrical power supply (connection of the step-down transformer to the Gauglin substation, blocking of the circuit-breakers, verification of the volumetric protection, closure of openings and valves, and positioning of cofferdams, etc.). The installation of the cofferdams, sandbags and mobile pumping resources and the closure of the watertight doors are totally dependent on human intervention. This type of organisation therefore fails to take account of a rapidly evolving event (for example such as a dam burst), a lack of accessibility to the platform as a whole or a lack of competent personnel at any given moment. ASN finds that EDF must study the possible development of passive resources, in other words that require no human intervention. 2.1.4 Monitoring of forecast criteria (meteorological, flood and tidal) The alert system (criteria and procedures to be followed in the various phases) is generally described in particular operating rules and instructions (CPC) associated with flooding. These alert systems generally consist of various phases (usually surveillance, vigilance, pre-alert and alert) during which specific actions are triggered. The criteria differ according to the sites (for example forecasting of wind speed and water levels at the Blayais intake, Rhone river discharge and discharge gradients at Bugey, Seine river discharge at Nogent). A national agreement was signed by Météo France and EDF DTG (General Technical Department) on 29th May 2009, providing the sites with the information necessary, particularly wind and precipitation, for anticipating a flood risk situation. There are other agreements, for instance with the SHOM (French naval hydrogaphic and oceanographic service) for tides, with the dam operator (for example at Bugey with the Compagnie Nationale du Rhône "CNR"). Some Government departments are also called on: for example, it is the Office of the Préfet of the Ain département which informs the Bugey NPP (nuclear power plant) of a 3 Provisional embankment or dam put in place to protect a zone.
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