Integral Scaling Analysis And Application For Sbloca In Large-scale Passive Plant

In the design process of IET,the scaling analysis is the core technology and key of the overall test,which is related to the reliability of the final result of the overall test.The purpose of the scaling analysis is to accurately simulate the various important thermo-hydraulic phenomena of the prototype system during the accident transient process on the scaled-down overall test bench,and to ensure that the test results have a reliable prototype system representativeness.Therefore,as the design basis of the overall experiment,the scaling analysis is a systematic analysis process,which includes the important thermo-hydraulic physical phenomena of the prototype system at each system level.The similarity criterion is obtained through the scaling analysis,and the design criterion of proportional test system is further obtained.The reliability of the test simulation could be ensured by ensuring these design criteria in the design process.The application of passive technology brings new challenges to the design,verification and safety review of nuclear power plants.In the design and safety review of large passive advanced pressurized water reactors,a proprietary test bench is required for the passive core cooling system and a number of overall performance tests should be carried out.This paper firstly regards the AP1000 power plant as the prototype,and uses the Relap5/MOD3 system program to calculate the SBLOCA process of it,to verify the correctness of the RELAP5 program model and the suitability for predicting the system response after the accident.Secondly,based on the H2TS method,the top-down and bottom-up analysis of the SBLOCA process is carried out,and the modeling conditions and scaling ratios that the IET needs to meet are identified.Then,the results of the scaling analysis are applied to determining the overall proportion of the IET and to verifying the suitability of the IET to simulate the actual SBLOCA process.By calculating the scaling ratio of the IET and the real power plant,it is proved from the perspective of proportional scaling that the IET can reasonably represent the response of the real reactor passive core cooling system under the accident,that is,the test data is credible.Further,this paper compares the scenarios of the 2.in SBLOCA process of real passive reactor predicted by RELAP5 program with the corresponding simulation test value of the IET,and confirms from the perspective of program calculation that the IET can well simulate the SBLOCA process of real passive reactor.Finally,the results of the proportional scaling analysis were applied to establishing the QPIRT for the SBLOCA of the AP1000 nuclear power plant.The traditional PIRT of AP1000 nuclear power plant is based on experts'knowledge and experiences,so it does not have the ability to make quantify judgments.Therefore,in order to support and test the traditional PIRT,this paper uses program simulation results of the AP1000 core part to perform a dimensionless analysis of program field equations,and then generate part of the dimensionless group(II group)to form a quantification PIRT(QPIRT)for the core region of the passive pressurized water reactor.Thereby verify the correctness of identifying important events and physical phenomena in the traditional PIRT and the accuracy of the best estimation program.