- 34 - generally, complete integration of experience feedback concerning the loss of heat sinks following the large-scale arrival of clogging material is an ongoing process that needs to be continued by EDF. 2.3.5 Anticipation: monitoring, prevention and detection resources In order to anticipate any problems related to the heat sink, EDF has set up technical and organisational arrangements for monitoring, prevention and detection of potential heat sink "hazards". Prevention of the clogging risk was looked at earlier ("integration of experience feedback"); this part looks at the steps aimed at preventing and detecting the other risks. ASN observed that certain sites had implemented agreements with other organisations so that they could receive warning and anticipate any problems related to the heat sink: river or dam operator organisations, weather forecasts, information network between various sites, independent port authority for estuary sites, etc. The inspectors found considerable organisational differences between the sites: for example, the Rhone river sites have not all concluded an agreement with the Compagnie Nationale du Rhône (CNR), the Nogent site has an agreement with the Voies Navigables de France (VNF), but the Chooz site has no agreement with the operators on the Meuse river or the manager of the Revin STEP (energy transfer pumping station), with the only possible "off-site" alert coming from the office of the préfet. Some sites analyse water quality, with trend monitoring to detect any changes, while others do not. This water quality monitoring, sometimes no more than just a visual inspection, is not systematically performed under quality assurance conditions (Saint-Alban, Chooz, Tricastin especially). The Le Blayais site has initiated research to improve its understanding of the river parameters to be monitored. The visual checks on the heat sink performed by the auxiliary operators are not always conducted under quality assurance conditions (for example at Golfech, Nogent among others). With regard to the risk of clogging by ice crystals (frazil), the inspectors saw that this risk was dealt with diversely and the measures sometimes need to be completed, for example by means of an arrangement making provision for a supply of hot water (at Flamanville, Golfech, Gravelines especially). The sites are required to take bathymetry (water depth) measurements of any silting or sanding at the water intake. Above a certain threshold, EDF begins dredging operations. The inspectors observed that this operation is correctly carried out on most of the sites. One of them, the Bugey NPP, which is potentially less exposed to the risk, has not taken any measurements for several years (2007 in fact). With regard to the detection resources, ASN observed that all the sites have instrumentation (sensors, etc.) capable of at least detecting a drop in the water intake. The inspectors noted that this equipment, which is not all classified important for safety (IPS), is often inadequately monitored. On several sites (Saint-Alban, Bugey, Chooz among others) the licensee was unable to prove that the equipment was serviceable because there were no checks logged under quality assurance. At Chooz and Bugey especially, the inspectors found a discrepancy between the local measurement and the instrumented flow measurement, which could lead to an overestimation of the actual flow. On the other hand, some sites such as Golfech have extended the scope of the checks beyond what is required by the frame of reference requirements. On this topic, the inspectors thus observe a disparity in the way the various risks are considered from one site to another, leading to differences in the measures taken. The precision with which the arrangements are implemented and monitored could on the whole be improved. 2.3.6 Management of cooling in a degraded situation The inspectors observed that all the sites have operating and control instructions for the facilities in the event of a degraded situation or climatic hazard. The special operating rules for extreme heat, extreme cold, frazil ice are known, available and implemented. Certain coastal sites, in particular Paluel, have also opted to apply "oil slick" risk management owing to a special operating rule known as "i-polmar". The inspectors did however observe that this procedure was not included in the personnel training curriculum. On coastal sites with oil slick booms, their deployment could be slowed down in certain cases owing to the absence of ad hoc anchorage or means of access. Moreover, the inspectors found that there were facility operating procedures to deal temporarily with an occasional loss of the heat sink. These are known to the sites. The inspectors found no major nonconformity on this point. Some sites are designed with a relative degree of independence: for example the Civaux NPP is self-sufficient for 10 days, while the Cattenom site could be independent for more than 15 days.
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