PUFF-III: A Code for Processing ENDF Uncertainty Data Into Multigroup Covariance Matrices

Dunn, M.E.

Oak Ridge National Laboratory

关键词: 99 General And Miscellaneous//Mathematics, Computing, And Information Science;    Manuals;    Multiplicity;    Nuclear Data Collections;    Spontaneous Fission;   

DOI  :  10.2172/763143
RP-ID  :  ORNL/TM-1999/235
RP-ID  :  AC05-00OR22725
RP-ID  :  763143

美国|英语

来源: UNT Digital Library

【 摘 要 】

PUFF-III is an extension of the previous PUFF-II code that was developed in the 1970s and early 1980s. The PUFF codes process the Evaluated Nuclear Data File (ENDF) covariance data and generate multigroup covariance matrices on a user-specified energy grid structure. Unlike its predecessor, PUFF-III can process the new ENDF/B-VI data formats. In particular, PUFF-III has the capability to process the spontaneous fission covariances for fission neutron multiplicity. With regard to the covariance data in File 33 of the ENDF system, PUFF-III has the capability to process short-range variance formats, as well as the lumped reaction covariance data formats that were introduced in ENDF/B-V. In addition to the new ENDF formats, a new directory feature is now available that allows the user to obtain a detailed directory of the uncertainty information in the data files without visually inspecting the ENDF data. Following the correlation matrix calculation, PUFF-III also evaluates the eigenvalues of each correlation matrix and tests each matrix for positive definiteness. Additional new features are discussed in the manual. PUFF-III has been developed for implementation in the AMPX code system, and several modifications were incorporated to improve memory allocation tasks and input/output operations. Consequently, the resulting code has a structure that is similar to other modules in the AMPX code system. With the release of PUFF-III, a new and improved covariance processing code is available to process ENDF covariance formats through Version VI.