The Development Of An Advanced Multigroup Library For PWRs

In the physics calculation of PWRs,multigroup calculation is usually performed first to get multigroup constants of cells or assemblies before diffusion calculation.Multigroup library provides constants for the first step calculation,which is usually developed bound to lattice codes.To a certain extent multigroup library determines the accuracy of codes.Therefore,it plays an important role in reactor physics calculation.At present,there are not many overt multigroup libraries.In order to realize independence of reactor physics calculation codes,many research institutes have developed their own reactor core design codes.But the libraries they generally use are the open WIMS formatted library or modified WIMS formatted library.Evaluate nuclear data libraries are always overt,and NJOY2016 nuclear data processing code opened recently,which makes a condition for developing a domestic multigroup library.The library is based on ENDF-6 formatted files,using NJOY2016 to calculate multigroup microscopic cross sections,and saved in a HDF5 formatted file.Moreover,a program called ACACIA for automatically generating libraries is developed.At first,derivation of multigroup equations and method of multigroup constants calculation,theory of NJOY2016,and properties of ENDF-6 formats and HDF5 formats are briefly introduced.Then the design and development process of ACACIA are expounded.Also,some testings are carried out to investigate the applicability on ENDF-6 formats.ACACIA can generate NJOY2016 input files and call the terminal to run NJOY2016,then collects nuclear data from output files of GROUPR module to a file in HDF5 formats.In addition,the program can generate continual energy nuclear data library in ACE formats.Then the composition and structure of multigroup library for PWRs are described in detail.Finally,comparison validation and codes validation are carried out on this library.Below is a list of conclusions: ACACIA program can automatically generate multigroup libraries.ENDF/B-VII.1,JEFF3.2 and JENDL4.0 have passed the testing on ACACIA with no fatal errors or warnings,accordingly the program fits well on ENDF-6 formats.The program improves efficiency of developing multigroup libraries and makes a condition for library updating.The library generated from ACACIA covers all nuclear data of depletion codes and lattice codes.It can be converted to assembly library used by lattice codes by compressing burnup chain,and to burnup library used by depletion codes by combining multigroup cross sections to one group cross sections.Comparison validation on the multigroup library developed for PWRs,based on JEFF3.2 and in SHEM-361 group structure came well.When used in depletion codes,results errors of all benchmarks were under limitation,indicating a well accuracy of the library.