Author/Authors :
J.L.Mu?oz-Cobo، نويسنده , , S.Chiva، نويسنده , , A.Escriv?، نويسنده ,
Abstract :
Inthispaper,wedevelopareducedordermodelwithmodalkineticsforthestudyofthedynamicbehaviorofboilingwaterreactors.Thismodelincludesthesubcooledboilinginthelowerpartofthereactorchannels.Newadditionalequationshavebeenobtainedforthefollowingdynamicsmagnitudes:theeffectiveinceptionlengthforsubcooledboiling,theaveragevoidfractioninthesubcooledboilingregion,theaveragevoidfractioninthebulk-boilingregion,themassfluxesattheboilingboundaryandthechannelexit,respectively,andsoon.Eachchannelhasthreenodes,oneofliquid,onewithsubcooledboiling,andonewithbulkboiling.Thereducedordermodelincludesalsoamodalkineticswiththefundamentalmodeandthefirstsubcriticalone,andtwochannelsrepresentingbothhalvesofthereactorcore.Also,inthispaper,weperformadetailedstudyofthewaytocalculatethefeedbackreactivityparameters.Themodeldisplaysout-of-phaseoscillationswhenenoughfeedbackgainisprovided.Thefeedbackgainthatisnecessarytoself-sustaintheseoscillationsisapproximatelyone-halfthegainthatisneededwhenthesubcooledboilingnodeisnotincluded.
