Research On Continuous Point Section Processing Method Based On Evaluated Nuclear Data Library

Evaluation of nuclear data library is an important basis for nuclear engineering design and nuclear technology research,but the evaluated nuclear data library cannot be directly applied to nuclear engineering design,but needs to undergo complex processing and then generate a nuclear data library for nuclear engineering design and nuclear technology application.The continuous energy point section library in ACE format required by the Monte Carlo programs MCNP and RMC is one of them.At present,programs with the function of generating ACE format libraries include NJOY,FRENDY,RXSP,NECP-Atlas,etc.Among these procedures,the NJOY program is the most widely used,but relevant studies have also found that NJOY is not processed correctly when dealing with neutron heat release,and it cannot be processed in processing high-energy evaluated nuclear data libraries.To this end,the IRPS laboratory of North China Electric Power University independently developed the advanced evaluated library processing program AXSP,the main functions of AXSP include formant reconstruction,doppler broadening,processing of indistinguishable formants,generation of continuous energy point cross-section,generation of multigroup cross-section,generation of multi-group covariance library and other modules.In this paper,the program ACEXS is developed based on the theory of continuous point section processing.ACEXS is a continuous energy point section processing module in AXSP program,the main function is to use the inverted stack method to convert the PENDF data after the reconstruction,doppler broadening,and indistinguishable formant processing into continuous energy point section data for Monte Carlo program.ACEXS solves the problem that the NJOY program cannot process high-energy evaluated nuclear data library.This paper first delves into the ACE format library processing theory,and then compares it with the probability distribution generated by the ACER module of NJOY to verify the correctness of program processing.Then,the critical reference questions,BN-600 reference questions and ZPR-6/7 reference questions in the ICSBEP reference manual are used to verify the accuracy of the continuous energy point section library generated by the program.After comparison,the relative error of the angular distribution probability density calculated by ACEXS and NJOY ACER did not exceed 0.3%,the relative error of cumulative density did not exceed 1.5%.the maximum error of probability density of various energy distributions did not exceed 2%.and the maximum error of cumulative density did not exceed 2%,and then 44 critical reference questions in ICSBEP were calculated,and the maximum absolute error of the calculated critical value ACEX and NJOY ACER did not exceed 50pcm.which was in good agreement.After that,the ZPR-6/7 and BN-600 reference questions were calculated.the absolute error of ZPR-6/7 critical value was 6pcm,the absolute error of BN-600 critical value was 15pcm,the corresponding flux distribution and power distribution also matched well,the relative error of the power of each fuel zone of BN-600 was within 0.1%,the relative error of the neutron flux in each ZPR-6/7 region was within 1%,and the relative error of only the low energy region was 4%.The reason is that the neutron flux in this energy region is very small,resulting in a large statistical error,and the other things are well matched.Finally,ACEXS tested the problem that NJOY could not calculate JENDL-HE/2007 high-energy evaluated nuclear data library normally,and the results showed that ACEXS could correctly handle the JENDL-HE/2007 highenergy evaluated nuclear data library,and the generated ACE format high-energy section library was complete and reasonable.