Consistent Data Assimilation of Isotopes: 242Pu and 105Pd

G. Palmiotti ; H. Hiruta ; M. Salvatores

关键词: 105 Pd;    242 Pu;    COSMO;    PROFIL-1;    PROFIL-2;    TRAPU-1;    TRAPU-2;    TRAPU-3;   

DOI  :  10.2172/1060977
RP-ID  :  INL/EXT-12-27127
PID  :  OSTI ID: 1060977

学科分类：核能源与工程

美国|英语

来源: SciTech Connect

【 摘 要 】

In this annual report we illustrate the methodology of the consistent data assimilation that allows to use the information coming from integral experiments for improving the basic nuclear parameters used in cross section evaluation. A series of integral experiments are analyzed using the EMPIRE evaluated files for 242Pu and 105Pd. In particular irradiation experiments (PROFIL-1 and -2, TRAPU-1, -2 and -3) provide information about capture cross sections, and a critical configuration, COSMO, where fission spectral indexes were measured, provides information about fission cross section. The observed discrepancies between calculated and experimental results are used in conjunction with the computed sensitivity coefficients and covariance matrix for nuclear parameters in a consistent data assimilation. The results obtained by the consistent data assimilation indicate that not so large modifications on some key identified nuclear parameters allow to obtain reasonable C/E. However, for some parameters such variations are outside the range of 1 s of their initial standard deviation. This can indicate a possible conflict between differential measurements (used to calculate the initial standard deviations) and the integral measurements used in the statistical data adjustment. Moreover, an inconsistency between the C/E of two sets of irradiation experiments (PROFIL and TRAPU) is observed for 242Pu. This is the end of this project funded by the Nuclear Physics Program of the DOE Office of Science. We can indicate that a proof of principle has been demonstrated for a few isotopes for this innovative methodology. However, we are still far from having explored all the possibilities and made this methodology to be considered proved and robust. In particular many issues are worth further investigation: ??? Non-linear effects ??? Flexibility of nuclear parameters in describing cross sections ??? Multi-isotope consistent assimilation ??? Consistency between differential and integral experiments