Hydraulic Characteristics Of Carr Heap

China advanced research reactor (CARR) is a high performance and multipurpose reactor which provide important science research platform for our country's nuclear scientific research. Plate type fuel assemblies are adopted in the core. Many parameters related to reactor safety should be ensured in thermal-hydraulic design for a new type reactor. The reactor internals are so complicated that thermal-hydraulic behavior is also complicated, in which may occur destructiveness vibration with the impact of the coolant. The way to resolve these problems is test verification.It is necessary to conduct numerical simulation for flow field of core and analyze its hydraulic characteristic before test verification. It can both provide technological basis for the test case (e.g. disposal of measurement point and simplifying the structure reasonably) so as to save the cost and the time of test and provide compared theory data that can judge the rationality of test result after the test verification.In order to meet the requirements of CARR project, the detailed numerical simulation and research are performed using CFD software. The major researches are outlined as following two aspects.1. Flow distribution calculation of whole core. Its emphasis is to calculate the flow distribution of each assembly in the core. The whole model is adopted in order to improve the veracity of calculation. Those fuel assemblies are simulated by porous media method, whose validity is verified at the same time.2. Analyzing reactor internals which might occur flow induced vibration in the flow field. The complex is divided into several parts for building model, which can increase number of calculation grid and improve the calculative precision of flow velocity around reactor internals, therefore, it is more exact for the appraisal of flow induced vibration. At last, all these reactor internals are evaluation according to the vibration mechanism of flow induced vibration.Through the above calculation and analysis and compared with the results of test, the following results can be concluded:1. The porous media method is effective. It will improve the economics of numerical analysis of engineering issues;2. The flow distribution factors among the same type assemblies are almost same, that has satisfied the demand of thermal-hydraulic design;3. For the analysis of flow induced vibration, the results of both theory analysis and test verification are same , and it's that all the reactor internals will not occur flow induced vibration. It has satisfied the demand of CARR design.4. Numerical simulation using CFD software is believable for the better consistent between simulation and test result.