Covariance data for ENDF/B-VI (Evaluated Nuclear Data File)

Conference · Wed Nov 01 04:00:00 EST 1989 · Transactions of the American Nuclear Society; (United States)

OSTI ID:5490270

Peelle, R W ^[1]

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1. Oak Ridge National Laboratory, TN (USA)

For ENDF/B-V (Evaluated Nuclear Data File), the Cross Section Evaluation Working Group recognized the need to quantify the uncertainty of the cross sections most important to applications. Covariance (here includes variance) formats and procedures were developed for the uncertainties in smooth cross sections and in isolated Breit-Wigner resonances. The goal was to allow propagation of the differential data uncertainties to yield uncertainty estimates for parameters calculated from the data base for applications having a broad neutron spectrum. One cannot rely on the variances (diagonal elements) alone, in part because the propagated uncertainty would then be strongly dependent on the fineness of the input data energy mesh. For ENDF/B-VI, developments and new covariance formats have made it possible to include covariance data to meet uncertainty propagation needs for pressure vessel dosimetry, fusion reactor activation, fast reactor core physics. The ENDF/B-VI evaluated covariance files can meet the requirements for uncertainty propagation and data adjustment because of broadened format capabilities and because of the increased experience with covariance data that is now possessed by measurers, evaluators, and users. Since covariance evaluation is demanding work, however, the first release of ENDF/B-VI will not contain all the needed information.

• OSTI ID: 5490270
• Report Number(s): CONF-891103--
• Conference Information: Journal Name: Transactions of the American Nuclear Society; (United States) Journal Volume: 60
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
220100* -- Nuclear Reactor Technology-- Theory & Calculation
ADJUSTMENTS
ADMINISTRATIVE PROCEDURES
BREIT-WIGNER FORMULA
CONTAINERS
COPPER
CROSS SECTIONS
DATA
DATA COVARIANCES
DOSIMETRY
ELEMENTS
EPITHERMAL REACTORS
EVALUATED DATA
FAST REACTORS
INFORMATION
METALS
NEUTRON DOSIMETRY
NUCLEAR DATA COLLECTIONS
NUMERICAL DATA
PHYSICS
PRESSURE VESSELS
REACTOR COMPONENTS
REACTOR CORES
REACTOR PHYSICS
REACTORS
SEMIMETALS
SILICON
TITANIUM
TRANSITION ELEMENTS