- 20 - dam failure, the Office of the Préfet of the Ardennes département which informs the Chooz NPP concerning Meuse river high water alerts. The inspections revealed a number of isolated anomalies which could compromise detection of these thresholds being reached and thus the appropriate action being taken in good time: absence of monitoring: Bugey (no monitoring of water levels for several days because the fax machine was out of paper), Nogent (range of instrumentation sensor values incompatible with the pre-alert phase threshold); absence of monitoring: Bugey (lack of stringency in filling out the Rhone river discharge monitoring procedures), Cruas (Rhone discharge values not updated frequently enough, certain values ignored); multiple criteria: Cruas, Blayais and Flamanville (different criteria depending on the documents); risk of erroneous values: Blayais (procedure fails to take account of the measurement uncertainties), Bugey (Rhone discharge value calculations essentially guesswork), Gravelines (no checks on meteorological forecast readings); no agreement with an organisation providing Rhone river discharge monitoring data: Saint-Alban. ASN finds that the monitoring of meteorological, high-water and tidal criteria needs to be improved. 2.1.5 Decision-making in an alert situation Responsibility for dissemination of information varies according to the organisation of the sites. On most sites, the site protection department receives the forecasts and transmits them to the control room. The information is sometimes sent directly to the control room (Nogent, Blayais). On most sites, the operations shift manager validates the phase changes triggering the specific measures of the planned procedures for dealing with a flooding risk. Meteorological, high-water or tidal data are generally correctly transmitted and interpreted. However, the inspectors noted: a lack of ergonomics in the alert procedures on certain sites (particularly Belleville, Cruas, Paluel, Saint-Laurent) liable to lead to confusion and thus erroneous or belated decision-making; a lack of communication between departments: Penly (tides monitoring file not shared by the departments), Fessenheim (the parties concerned are insufficiently familiar with the organisation put into place for transmission of the meteorological data to the operations department), Cruas (shift operations manager not informed of changing discharge rates frequently enough, no reactor designated as pilot). ASN finds that implementation of the flood alert system on the sites needs to be improved. 2.1.6 Implementation of procedures Some sites were concerned by situations requiring the transition to the vigilance phase or activating of the site flood safety PUI (for example Fessenheim in 2007, Belleville in 2008, Blayais in 2009 and 2010, Bugey, Saint-Alban and Tricastin in 2010). The experience feedback is on the whole positive. However, the sites of Tricastin and Saint-Alban were unable to present the inspectors with the completed operations procedure corresponding to the last transition to vigilance phase, in particular the part corresponding to volumetric protection control. ASN therefore finds that during the course of actual crises, the instructions were on the whole followed, but that improvement is needed on certain sites. 2.1.7 Actions and modifications performed following the event at Le Blayais For each site, a report defines the work to be performed as a result of the operating experience feedback from the partial flooding of the Le Blayais site in December 1999. This work can consist in installation of cofferdams, closures, seals between buildings, raising or building embankments, etc. The inspectors checked that the deadlines were met and that upkeep and monitoring were performed in compliance with the recommendations. Some sites apply the modifications in full (Cattenom, Fessenheim, Belleville). Others are in the process of doing so, in accordance with the planned deadlines (Saint-Laurent, Tricastin, Dampierre).
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