Processing Neutron Cross Section Covariances using NJOY-99 and PUFF-IV.

Arcilla, R. ; Kahler, A. C. ; Oblozinsky, P. ; Herman, M.

Technical Information Center Oak Ridge Tennessee

关键词: Cross sections;    Neutrons;    Nuclear Data Collections;    Data processing;    Algorithms;   

RP-ID  :  DE2008939953

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

With the growing demand for multigroup covariances, the National Nuclear Data Center (NNDC) has been experiencing an upsurge in its covariance data processing activities using the two US codes NJOY-99 (LANL) and PUFF-IV (ORNL). The code NJOY-99 was upgraded by incorporating the new module ERRORJ-2.3, while the NNDC served as the active user and provided feedback. The NNDC has been primarily processing neutron cross section covariances on its 64-bit Linux cluster in support of two DOE programs, the Global Nuclear Energy Partnership (GNEP) and the Nuclear Criticality Safety Program (NCSP). For GNEP, the NNDC used NJOY-99.259 to generate multigroup covariance matrices of (sup 56)Fe, (sup 23)Na, (sup 239)Pu, (sup 235)U and (sup 238)U from the JENDL-3.3 library using the 15-, 33-, and 230-energy group structures. These covariance matrices will be used to test a new collapsing algorithm which will subsequently be employed to calculate uncertainties on integral parameters in different fast neutron-based systems. For NCSP, we used PUFF-IV 1.0.4 to verify the processability of new evaluated covariance data of (sup 55)Mn, (sup 239)Pu, (sup 233)U, (sup 235)U and (sup 238)U generated by a collaboration of ORNL and LANL. For the data end-users at large, the NNDC has made available a Web site which provides a static visualization interface for all materials with covariance data in the four major data libraries: ENDF/B-VI.8 (47 materials), ENDF/B-VII.0 (26 materials), JEFF-3.1 (37 materials) and JENDL-3.3 (20 materials).