Benchmark For The Results Of Reactor Core On-line Simulation Using NGFM

The development of reactor core physics on-line simulation system is very important to nuclear power plant design, operation and the training for operators. The key is located on the appropriate reactor core physics calculation model as well as a highly active and stable calculation method. NGFM (Nodal of Green's Function Method) was used for the calculation of power distribution. Furthermore the program code will be transplanted to the simulation system.According to the analysis of the construction and functions of NGFM/TNGFM program, the function of each subroutine and the physical significance of each variable are known. Then the steady state program NGFM is used for checking computations of the 2D-TWIGL benchmark, also the results of QINSHAN- II nuclear power station reactor physics simulation are checked out. Moreover the transient state program TNGFM is used for transient calculation of the 3D-LMW benchmark. The variations of reactor core power distribution depending on the movement of control rods are simulated.Based on the results of the calculation above, the conclusions can be drawn that the structure of Nodal Green's function Method program NGFM/TNGFM is distinct, which can be easily read and transplanted. The rate of convergence of NGFM code is very fast. It takes only 1/10 seconds of fine-structure mesh difference program to achieve the same accuracy standard. The intermediate variables of the calculation are the partial neutron currents of node surfaces, which are necessary to fine power reconfiguration. The time steps of transient calculation program can be chose flexibly, and the accuracy of which is high. The NGFM/TNGFM codes can be coupled with thermo-hydraulics analysis program. Therefore the NGFM applicable for the module of reactor core physics calculation in the simulation system.