AnalysisoflowloadtransientsfortheVandellòs-IINPP:ApplicationtooperationandcontrolsupportOriginalResearchArticle

TheTechnicalUniversityofCatalonia(UPC)hasbeenjointlyworkingwiththeAsociaciónNuclearAscó-Vandellòs(ANAV)foranumberofyearsinordertoestablish,qualifyandusebestestimate(BE)modelsforthereactorsunderthecontrolofANAV.ANAVistheconsortiumthatisresponsibleforoperationoftheAscóandVandellòs-IIreactors.ThereactorsareWestinghouse-designthree-loopPWRswithanapproximateelectricalpowerof1000MW.Theexistingintegralplantmodelsforeachplantarecurrentlyusedformanydifferentpurposesamongwhicharesupportofplantoperationandcontrol.Quiteanumberofstudieshavebeendoneinordertoimprovebothsafetyandplantcompetitiveness.Mostofthesedynamicanalyseswerecarriedoutinrelationtotransientsstartingatnominalfullpoweroratleast,veryclosetofullpower.ThispaperdevelopsaspecificuseoftheVandellòs-IIplantmodelforoperationandcontrolsupportatlowpowerinvolvingnewrangesofsystemactuationparameters.Italsoexaminesscenariosthataresomewhatdifferentfromthosetypicallyanalysed.Thestudystartsshowingtheresultsofanassessmentcase,whichisastart-uptestandprovidessomeadditionalqualification,andsubsequentlyattemptstoestablishcalculationstosupportbothanimprovementinfeedwatercontrolsandtosetupoperatingrecommendationsforlow-loadmanualoperationoffeedwaterturbo-pump.Bothresultshopefully,willproduceanoutcome,whichleadstoanimprovementinsafetyandreducesreactortripprobability.