Research On Characteristics Of Passive Residual Heat Removal System For Anvanced Reactor

This paper takes the Daya Bay Nuclear Power Station as research object, and designs anew secondary passive residual heat removal system (SPRHRS) by the use ofRELAP5/MOD3.2. The function of SPRHRS is verificated under different accidents.Based on the prototype of Daya Bay Nuclear Power Station and its primary designparameters, the related parameters of SPRHRS is tentativly designed, the model of thesimplified system for primary system and SPRHRS is established by the use ofRELAP5/MOD3.2code. First, the auxiliary feed water(AFW) is input under the stationblackout(SBO) accident in order to gain the change regulation of the primary and secondaryloop in the main system.Then, SPRHRS is input instead of AFW under SBO accident in orderto validate its mitigation capability，on this base，sensitivity analysis for the related parameterswhich affect the working characteristics of SPRHRS, such as volume of high-level tanks, areaof heat exchanger, height difference of cold and heat core and the input time of SPRHRS ismade in order to estimate the affections of these parameters on working characteristics ofSPRHRS. At last, the function of SPRHRS is further verificated in the more serious Ⅳcondition---the SBO superimposed on main feedwater line break(MFLB) accident, and theresponse characteristics of the system in unexpected input of SPRHRS under normaloperation is simulated.The calculation has the following conclusions: Natural circulation is quickly establishedafter accident, which removes the core residual heat effectively and keep the core safe underaccidents, so the rationality and effectiveness of SPRHRS is proved; Increasing volume ofhigh-level tanks and area of heat exchanger helps to remove residual heat of the core;Reducing height difference of cold and heat core has little influence on the capacity of naturalcirculation for SPRHRS; The earlier input of SPRHRS, the higher of the water level in thesecondary loop in steam generator, and the better for removing residual heat in the core.In thenormal operation condition,the unexpected input of SPRHRS has no influence on mainsystem due to the check valve.