Monte Carlo Program Neutron Cross-section Online Doppler Broadening Study

In the simulation of nuclear reactor coupled multi-physics,the temperature effect of the fuel is one of the most important phenomena in reactor physics.During the nuclear reactor operation,the fuel temperature changes from 300K to 1000K.It would cause the thermal motion of the fuel nuclide with the change of fuel temperature.Also this phenomenon is called as the Doppler Effect.It is well known that the Doppler coefficient of UO2 fuel changes between-1.0?-5.0 pcm/K.The temperatures difference between the thermal zero power and full power in reactor operation causes totally 1000 pcm difference in reactor activity.In recent years,with the development of the computing speed and performance of supercomputer,it is possible to apply the Monte Carlo method into the simulation of nuclear reactor full core by pin-by-pin.As it is well known,nuclear cross section data libraries are essential for nuclear reactor calculation.In general,the nuclear cross section data libraries are generated by NJOY code before conducting particle transport calculation.During the nuclear reactor operation,the big difference of fuel temperature in different regions exists.If the cross section libraries are generated by NJOY code on time,it would take a long time.Facing of this challenge,many papers have been studied on the research of On-the-flying Doppler Broadening.JMCT is high-performance numerical simulation software developed by IAPCM.It is a three-dimensional neutron,photon,electronics and neutron/photon/electronics coupling transport Monte Carlo program,which is used for numerical reactor multi-physics coupling simulation.This paper will focus on some well-studied on-the-flying Doppler Broadening methods and choose the one method with the minimum error and maximum efficiency.This algorithm has been putted into the JMCT code.