Evaluation Of Neutron-induced Fission Yield Data Of ²³⁵U

Fission yield is an important nuclear data base for the study of nuclear energy and nu-clear devices.It is used to determine the burnup depth of reactors and calculate the power of nuclear devices.In addition,it has important applications in verification and nuclear power plant safety.In addition,it also plays an important role in the study of nuclear fission mechanism,the formation mechanism of heavy elements in celestial bodies,neutrino anomaly and other basic scientific research.Fission is the main nuclear reaction process in the combustion process of nuclear de-vices,and ²³⁵U is an important fuel for reactors and nuclear devices,so the nuclear data of²³⁵U has special significance in the field of nuclear energy and nuclear devices,inclu ding fission yield.Among them,⁹⁵Zr,⁹⁹Mo,¹⁴⁴Ce and ¹⁴⁷Nd produced by fission are important indicator nuclei,which are of great significance for the study of power.At present,these evaluation data are inconsistent in the international community,which brings great uncer-tainty to the corresponding scientific research.The users put forward the urgent demand,request to carry on the reevaluation to these production amount,recommend to give the reasonable production amount value.The nuclear cumulative yield of these important products was evaluated in this pa-per.The experimental data are mainly from the EXFOR experimental database.According to the measurement date and experimental technical method,the output data and errors are preliminarily screened and processed,and then the standard output and branch ratio are updated and corrected.For yield ratio Q and bi-ratio R measured by relative method,the latest data of reference kernel are converted into yield value.The yield data were obtained by the above method,and the yield value and error were further obtained by weighted a v-erage,which were used as the recommended evaluation value of yield,and compared with data from other international libraries,such as ENDF/B-VII.1,JEFF-3.1,and JENDL-4.⁹⁹Mo is often used as a standard yield in fission yield studies,but there are great dif-ferences in the fission spectral energy region.Through the analysis of yield ratio data,a new yield value is given,which is about 5%higher than the data given by ENDF/B-VII.1.The yield ratio method adopted in this work can eliminate part of the system error,so it has higher reliability.Using this method,we made a similar analysis of the nuclear yield data of other important products with ratios.In addition,other product nuclei of n+²³⁵U were collected and evaluated in this work,and the evaluation results were compared with the international ENDF/B-VII.1and JEFF-3.1 databases,and the resulting differences were also compared and analyzed,and a more credible recommended value was finally given.The evaluation results are basically consistent with the international database,and most of the fission product yield energy re-lations are consistent with the experimental data.The recommended value for the output data is highly reliable.The above work provides an effective reference for the construction of China evalua-tion nuclear database?CENDL?.