report

Belgian stress tests action plan ‐ 2012‐12‐14No Topic Source Recommendations, Requirements from other national reviews Action : Family ‐ subfamily ‐ sub‐subfamilyActions to beimplementedComment29Natural hazards(weather)National regulatoryinspectionHeavy rainfallsThe reassessment of the capacity of the sewer system (five separate networksat Doel, separate networks per unit at Tihange), using a detailed hydrodynamicmodel must cover both short‐duration heavy rains and long‐lasting rains (95thpercentile) for return periods up to 100 years. Moreover, to define such 100‐ External hazards ‐ Extreme weather conditions ‐yearly rains, observations of rain intensities over a sufficiently long period of Sewage capacity evaluationtime must be used, including the latest observations (e.g. the exceptional rainof 23rd August 2011). Depending on the results, potential improvements of thesewer system shall be envisaged and the licensee’s action plan shall be updatedaccordingly where appropriate.439, 443, 546, 584§ 7.2.3 of national stresstests report30Natural hazards(weather)National regulatoryinspectionTornadoesGiven the fact that tornadoes of high intensities were observed in the pastyears in the neighbouring countries (class EF4 on the enhanced Fujita scale),the robustness of the second level systems of Doel 1/2 and Tihange 1 should beconfirmed in case of a beyond‐design tornado with wind speed exceeding 70m/s (250 km/h).External hazards ‐ Extreme weather conditions ‐Confirmation of resistance to tornadoesExternal hazards ‐ Flooding ‐ Availability of theadditionnal means against extreme flooding441, 547§ 7.2.3 of national stresstests report31 Design issuesNational regulatoryinspectionNon conventional meansThe operability of the non conventional means should be justified on the basisof technical data (design, operation, alignment and connections, periodictesting, preventive maintenance, etc.).Emergency management ‐ Requirements ‐Specifications of mobile means400, 515, 541§ 7.2.4 of national stresstests report32Design issuesNational regulatoryinspectionNon conventional meansThe technical characteristics of the non‐conventional means (NCM) shouldaccount for the adverse (weather) conditions they may be subject to during thewhole period of operation.Emergency management ‐ Infrastructure ‐ On‐siteresistant storage for mobile meansEmergency management ‐ Requirements ‐Specifications of mobile means400, 509, 515, 572, 573§ 7.2.4 of national stresstests report33 Design issuesNational regulatoryinspectionExternal power sourcesThe licensee should, in collaboration with ELIA, manager of the high voltagenetwork, make a feasibility study to ensure a better geographical separation ofthe high voltage lines (380 and 150 kV) to further improve the reliability of theexternal power supply to the NPPs. In addition, the licensee should, inagreement with ELIA, ensure that in case of LOOP the NPPs have the highestpriority for reconstruction of the external power supply to the NPPs. Theregulatory body shall take the necessary steps, in collaboration with othercompetent authorities, to ensure the fulfilment of this recommandation.Power supply ‐ Varia ‐ Impact of the configurationand operation of High Voltage grid on the auxiliariesof NPP's503, 550§ 7.2.4 of national stresstests report34Design issuesNational regulatoryinspectionStation black‐outIn relation to the “total SBO” scenario, the potential overfilling or draining ofthe steam generators due to the loss of ultimate compressed air should beexamined.Water supply ‐ Total Station Black‐out ‐ Steamgenerator protectionsWater supply ‐ Total Station Black‐out ‐ Turbopomppower supply backup219, 220, 221, 495§ 7.2.4 of national stresstests reportAdditional topics5/9